Europe/Prague
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#### Casino Conference Centre

Reitenbergerova 4/95, Mari&#225;nsk&#233; L&#225;zn&#283;, Czech Republic <font color=white>
Description
Participants
• Agata Oszczak
• AGNIESZKA FULARA
• Ainon Hamzah
• Aleksander Bilewicz
• Aleksey Troshin
• Alena Tokarova
• Alexander Kostylev
• Alexander Mansel
• Alexander Popkov
• Alexander Yakushev
• Alexey Rodin
• Alexey Safonov
• Aleš Vetešník
• Alicia Negron-Mendoza
• Amares Chatt
• Andreas Geist
• Andreas Tuerler
• Andrei Androsov
• Andrew Hodgson
• Andy King
• Anna Bajzíková
• Anna Rubailo
• Anton Fiskov
• Antonia Denkova
• Atsushi Toyoshima
• Barbara Jutta Maria Karches
• Barbora Drtinova
• Barbora Maresova
• Bayirta Egorova
• Benjamin Cvetkovic
• Bernhard Scholten
• Bert Wolterbeek
• Bogdan Wąs
• Boris Andris
• Borja Gonzalez Prieto
• Canh Hai Nguyen
• Catarina Galinha
• Celine GAUTIER
• Chris Maher
• Christian Bustillos
• Christian Ekberg
• Christian Schreinemachers
• Christian Stieghorst
• Christophe Bruggeman
• CHUAN-PIN LEE
• Claudia Landstetter
• Cory Hawkins
• Daniel Seifert
• David Chvatil
• David Teze
• Denis Glavič-Cindro
• Dmitriy Grozdov
• Dmitry Marinin
• Dusan Galanda
• Dusan Vopalka
• Edyta Łokas
• Eiliv Steinnes
• Ekaterina Kukleva
• Ekaterina Potanina
• Elena Belova
• Elena Laura Ebert
• Elena Zakharchenko
• Emilie BOSSE
• Emma Aneheim
• Ernesto Martínez Baez
• Eros Mossini
• Euo Chang Jung
• Eva Hofmanova
• Eva Juranova
• Eva Málková
• Ewa Starościak
• Ferenc Fabian
• Fernando P. Carvalho
• Frans De Corte
• Gabriela Teodorov
• Gabriela Wallova
• Gabriele Wallner
• Galina Lujaniene
• Gospodin Bozhikov
• Grazyna Przybytniak
• Grzegorz Olszewski
• Grzegorz Romanczyk
• Guozhong Wu
• Hanna Tuovinen
• Hans Vigeland Lerum
• Heino Nitsche
• Hiromitsu Haba
• Hisaaki Kudo
• Igor Izosimov
• Ilya Usoltsev
• Inga Zinicovscaia
• Ioannis Pashalidis
• Irena Spendlikova
• Irina Vlasova
• Iva Vosahlikova
• Ivan Hupka
• Ivan Kajan
• Ivana Krausova
• Ivana Milanovic
• Ivo Světlík
• Iwona Bartosiewicz
• Jakub Kuba
• Jakub Raindl
• Jakub Visnak
• James Holt
• Jan Barta
• Jan John
• Jan Kamenik
• Jan Kozempel
• Jan Krmela
• Jan Kucera
• Jan Tits
• Jana Socuvkova
• Jana Sulakova
• Janelle Droessler
• Janja Smrke
• Jaroslav Červenák
• Jenny Halleröd
• Jerzy Narbutt
• Jerzy-Wojciech Mietelski
• Jiri KOTRBA
• Jiri Landa
• Jiri Vacik
• Jitka Prajsova
• Jixin Qiao
• Jiří Janda
• Jiří Mizera
• Jon Petter Omtvedt
• Jong Myoung Lim
• JongHwa MOON
• Josef Anton
• Josef Chudoba
• Joung Hae Lee
• Juan F. Facetti-Masulli
• Judit Krajkó
• Jukka Lehto
• Julie Champion
• Jussi Ikonen
• Kamil Vavrinec Mares
• Kamila Kołacińska
• Kamila Šťastná
• Karolina Szymanska
• Katerina Videnska
• Kateřina Čubová
• Katharina Fritsch
• Katja Schmeide
• Kattesh Katti
• Kenneth Czerwinski
• Keri Campbell
• Kevin Galliez
• Kil Yong Lee
• Kirill Romachevsky
• Konstantin Dvoeglazov
• Krzysztof Borowik
• Krzysztof Kleszcz
• Kun Ho Chung
• Kwang-Rag Kim
• Leila Safavi-Tehrani
• Lenka Hrušková
• Lenka Procházková
• Leon Fuks
• Lidia Rosiak
• Lijuan Qian
• Lixin Sun
• Ljudmila Benedik
• LORANT SZATMARY
• Lucie Kománková
• Lyubomir POPOV
• Lyudmila Golovkina
• M Alkhorayef
• Magdalena Dlugosz-Lisiecka
• Magdalena Gumiela
• Magdalena Rejnis
• Marek Bystran
• Maria do Carmo Freitas
• Maria Efstathiou
• Maria Lübke
• Marina Frontasyeva
• Marja Siitari-Kauppi
• Marta Pyszynska
• Martin Cabalka
• Martin Precek
• Martin Vlk
• Martina Benesova
• Masanobu Nogami
• Masashi Murakami
• Maxim Samsonov
• Mayya Kalenova
• Melanie Müller
• Michael Krachler
• Michal Pokorný
• Michiko Fukushima
• Michio Aoyama
• Miia Lampén
• Mikhail Alyapyshev
• Milan Bunata
• Min Hoon Baik
• Ming-Chee Wu
• Mingli Zhang
• Miroslava Stilijanova
• Mojmír Němec
• Myroslav Zoriy
• Najat Kassim Mohammed
• Natalia Gomzina
• Natallia Torapava
• Nicholas Evans
• Nikolay Aksenov
• Nora Vajda
• Oldrich Navratil
• Oleksiy Itsenko
• Olga Gorbunova
• Olga Mokhodoeva
• Olga Shudegova
• Ondřej Lebeda
• Otilia Ana Culicov
• Pavel Bartl
• Pavel Bláha
• Pavel Bobrov
• Pavel Krist
• Pavel Povinec
• Pavol Rajec
• Peter Burns
• Peter Ivanov
• Peter Medley
• Petr Distler
• Petr Večerník
• Petr Vokac
• Petra J. Panak
• Petra Količová
• Petra Kudejova
• Petra Mičolová
• Piotr Szajerski
• Przemyslaw Kozminski
• Qiuxiang Cao
• Rajamani Natarajan
• Remi Poirot
• Rick Paul
• Robin de Kruijff
• Rolf Zeisler
• Ruveyda Kubra ILERI
• Sami Alwaer
• Sandor Takacs
• Sascha Wisser
• Semen Zavarzin
• Sergey Vinokurov
• Sergio Ramos-Bernal
• Seung Soo KIM
• Seweryn Krajewski
• Shan Xing
• Silvia Dulanská
• Sinikka Virtanen
• Sobeslav Neufuss
• Sofia Jonsson
• Stanislav ERMOLAEV
• Stefan Neumeier
• Steffen Happel
• Sukiman Sarmani
• Sung-Hee Jung
• Svetlana Tretyakova
• Svyatoslav Nikitin
• Tatiana Boytsova
• Tatiana Khaustova
• Tatiana Kuzmina
• Tatiana Livshits
• Tatiana Semenova
• Teija Koivula
• Tereza Pavelková
• Terezia Nemcova
• Thierry MENNECART
• Tibor G. Kocsor
• Timothy Payne
• Tobias Wels
• Tomas Koubsky
• Tomas Prajs
• Tomas Rosendorf
• Valeriy Luchnikov
• Valiantsina Torapava
• Vallín García Cruz
• Vanessa Sanders
• Vasiliy Babain
• Vera Mazgunova
• Veronika Kocurova
• Veronika Mocko
• Viktor Golias
• Viktoria Damberger
• Viktória Sántáné Gerse
• Vojtech Brynych
• Václav Čuba
• Václava Havlová
• Věra Bečková
• Weiqun Shi
• Wilhelm Hans EUGEN SCHWARZ
• Xiaolin Hou
• Yuichiro Nagame
• Yulia Buchatskaya
• Yulia Konevnik
• Yulia Voskresenskaya
• Yuriy Demidov
• Yutaka Miyamoto
• Zana Bikbajeva
• Zeljko Grahek
• Zsolt Révay
• Zsolt Varga
• Łukasz STECZEK
• Štěpánka Maliňáková
Support
• Sunday, May 11
• Registration Foyer

### Foyer

#### Casino Conference Centre

Reitenbergerova 4/95, Mari&#225;nsk&#233; L&#225;zn&#283;, Czech Republic <font color=white>
• Welcome drink / Opening ceremony Marble Hall

### Marble Hall

#### Casino Conference Centre

Reitenbergerova 4/95, Mari&#225;nsk&#233; L&#225;zn&#283;, Czech Republic <font color=white>
• Hevesy Medal Award Ceremony Mirror Hall

### Mirror Hall

#### Casino Conference Centre

Reitenbergerova 4/95, Mari&#225;nsk&#233; L&#225;zn&#283;, Czech Republic <font color=white>
Conveners: Prof. Amares Chatt (Dalhousie University), Prof. Jan John (CTU in Prague, FNSPE, Department of Nuclear Chemistry)
• 1
In the spirit of the Hevesy Award, this talk will cover selected examples of my research during the last four decades. My work has been focused on the chemistry of the actinides and the superheavy elements. I will discuss research within actinide chemistry related to solution thermodynamics of uranium, neptunium, plutonium, and americium, as well as their sorption and biological interactions with geologic matrices, for the performance assessment of potential high-level nuclear waste repositories and environmental remediation. Additionally, I will present my work on the physics and chemistry of the heaviest elements, including the confirmation of new elements, discovery of new isotopes, and one-atom-at-a-time chemistry.
Speaker: Prof. Heino Nitsche (UC Berkeley and Lawrence Berkeley National Laboratory)
• Welcome reception Marble Hall

### Marble Hall

#### Casino Conference Centre

Reitenbergerova 4/95, Mari&#225;nsk&#233; L&#225;zn&#283;, Czech Republic <font color=white>
• Monday, May 12
• Registration Foyer

### Foyer

#### Casino Conference Centre

Reitenbergerova 4/95, Mari&#225;nsk&#233; L&#225;zn&#283;, Czech Republic <font color=white>
• Plenary session 1 Mirror Hall

### Mirror Hall

#### Casino Conference Centre

Reitenbergerova 4/95, Mari&#225;nsk&#233; L&#225;zn&#283;, Czech Republic <font color=white>
Conveners: Prof. Heino Nitsche (UC Berkeley and Lawrence Berkeley National Laboratory), Prof. Jan John (CTU in Prague, FNSPE, Department of Nuclear Chemistry)
• 2
Fukushima Accident: Radioactivity Impact on environment, land and ocean
Radioactive materials were released to the environment from the Tokyo Electric Power Company Fukushima Dai-ichi Nuclear Power Plant (FNPP1) as a result of reactor accidents caused by a total loss of electric power (black out) after the Tohoku earthquake and tsunami on 11 March 2011. Radioactive materials were emitted into the atmosphere and transferred to the land and ocean through wet and dry deposition. In addition, highly contaminated water was directly released to the ocean. Therefore radioactive materials were released to the ocean by two major pathways, atmospheric deposition and direct release from the site. Regarding with 137Cs, ca. 2% of 137Cs (15 PBq) of total inventory of the three melt down cores of which total inventory was 700 PBq, were released into the atmosphere then 80 % of atmospheric release were deposited in the ocean. Twenty percent of 137Cs (141 PBq) were dissolved in the stagnant water in turbine buildings and surrounding areas by the accident. 0.5 % of 137Cs (3.5 +- 0.7 PBq) were directly released in the ocean. Since the 134Cs to 137Cs activity ratio was almost 1 at the time of the accident, same amount of 134Cs were injected in the environment as well as that of 137Cs stated above. The total amount of deposited 137Cs in Japan was estimated to be 2.9 PBq based on aerial monitoring in Fukushima prefecture and daily deposition monitoring at 50 stations in each prefecture. The oceans are important sinks of anthropogenic pollutants, such as radionuclides, heavy metals and organic compounds, that are mainly atmospherically derived and/or directly discharged, but there is little information on their overall transport process during several decades after their injection. The bulk of the anthropogenic radionuclide 137Cs present in the oceans today was injected about five decades ago from atmospheric nuclear weapons tests and total inventory of 137Cs in the North Pacific Ocean was 69 PBq just before the FNPP1 accident. Until the end of 2011, a main body of Fukushima derived radiocaesium were existed at surface layer, however, after winter cooling 2011/2012 we found subsurface maximums of Fukushima derived 134Cs and 137Cs due to subduction in the subtropical gyre in the North Pacific Ocean. The subsurface maximums corresponded wiith SubTropical Mode Water (STMW) and Central Mode Water (CMW). The water column inventory shallower than 200 meters depth in November 2011 at 40 deg. N, 165 deg. E was 80 % of total, while it decreased 20 % in June 2012. In winter 2013/2014, 137Cs activity in surface water close to the FNPP1 site is still around 1000 Bq m-3 while a maximum of Fukushima derived 137Cs in surface water were observed at the eastern part of the North Pacific Ocean and the 137Cs activity was a few Bq m-3 which is already close to pre-Fukushima level and 134Cs activity in surface water was less than 1 Bq m-3.
Speaker: Prof. Michio Aoyama (Institute of Environmental Radioactivity, Fukushima University)
• 3
Speaker: Prof. Xiaolin Hou (Technical University of Denmark, Center for Nuclear Technologies)
• 4
Positioning the New Elements in the Periodic Table
With the discovery of six new elements in the past decade an extraordinary expansion of the Periodic Table took place, so that now all elements of the 7th period have been synthesized. This success was possible by exploiting the concept of “warm” fusion using the available, neutron-rich actinide target materials and the tightly bound, doubly magic projectile 48-Ca [1]. Most of these discovery experiments were conducted by the Dubna-Livermore collaboration at the Flerov Laboratory in Dubna, Russia and a number of independent experiments have been able to confirm these findings [2-4], most recently for element 117 [5]. Due to the discovery of relatively long-lived isotopes of copernicium (element 112) and flerovium (element 114) first chemical experiments have successfully been conducted, revealing the special chemical properties of these elements, which can be attributed to the influence of strong relativistic effects [6,7]. Substantial progress has also been achieved in investigating the lighter heavy actinide and transactinide elements, where new properties of heavy actinide elements and new classes of tansactinide containing compounds have been synthesized. In my lecture I will review these recent developments and give an outlook on upcoming opportunities for chemical investigations of heavy and superheavy elements. [1] Yu.Ts Oganessian, J. Phys. G: Nucl. Part. Phys. 34, R165 (2007) [2] L. Stavsetra et al., PRL 103, 132502 (2009) [3] Ch.E. Düllmann et al., PRL 104, 252701 (2010) [4] S. Hofmann et al., EPJA 48, 1 (2012) [5] J. Khuyagbaatar et al., PRL in press (2014) [6] A. Türler, V.G. Pershina, Chem. Rev. 113, 1237 (2013) [7] A. Yakushev et al., Inorg. Chem. 53, 1624 (2014)
Speaker: Prof. Andreas Türler (Paul Scherrer Institute and Bern University)
• 10:00 AM
Coffe Break Marble Hall

### Marble Hall

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Reitenbergerova 4/95, Mari&#225;nsk&#233; L&#225;zn&#283;, Czech Republic <font color=white>
• Plenary session 2
Conveners: Prof. Andreas Türler (Paul Scherrer Institute and Bern University), Prof. Michio Aoyama (Institute of Environmental Radioactivity, Fukushima University)
• 5
Comparison of eight possible 99-molybdenum production routes
The present paper addresses eight possible routes of producing 99Mo, and discusses both yield and 99Mo specific activities (SA) in the context of future anticipated worldwide demand. The dimensions of the targets are modelled by considering both the limits set by cooling and those by inside-target radiation attenuation characteristics. Energy deposition profiles are modelled by MCNP6, the reaction probabilities are taken from TALYS/TENDL and JANIS codes, and both are used in calculating produced 99Mo. The results suggest that U neutron-fission may remain one of the most relevant and efficient means of producing 99Mo, but that new developments may surface, such as ADSR or AHR production modes. Accelerator- based 99Mo production is discussed as asking for developments in both the cooling of targets and new concepts in post-EOB upgrading of 99Mo SA, and/or new concepts for 99Mo/99mTc-generators, the latter possibly in both volumes (mass) and 99Mo capacities.
Speaker: Prof. Bert Wolterbeek (Delft University of Technology)
• 6
Chemistry for the Future Nuclear Fuel Cycles
Actinide chemistry is at the centre of key issues to be faced by nuclear energy. Indeed, in addition to an increased safety of the reactors themselves, the acceptance of the nuclear energy is still closely associated to our capability to reduce the lifetime of the nuclear waste, to manage them safely in a long term disposal and to propose options for a better use of the natural resources. Before implementing a process at the industrial level, it is of primary importance to increase our fundamental knowledge in actinide sciences in terms of safety, fabrication and performance of fuels, reprocessing and long term waste management. Among FP7-EURATOM Framework Program, a few projects work closely to address the challenges of future fuel cycles. Among them, SACSESS (Safety of ACtinide SEparation proceSSes) and TALISMAN work to improve our knowledge in actinides chemistry in order to develop advanced separation processes. SACSESS is focused on the development of safe advanced separation processes, both aqueous and pyrochemical. Head-end steps, fuel refabrication, solvent treatment, waste management are also taken into account. TALISMAN (Transnational Access to Large Infrastructures for a Safe Management of ActiNides) gives European researchers the opportunity to come and work in unique facilities. By offering transnational access to the main European nuclear research facilities, TALISMAN aims at increasing the knowledge in actinide sciences by gathering all the expertise available in nuclear research institutes or university in Europe and giving them the opportunity to come and work in hot-labs or beamlines. Exchanges and complementarities are also established with other Euratom initiative (ASGARD, CINCH-II…) to cover broadly the nuclear fuel cycle challenges. In all projects, efforts have been made to increase collaborations, mutualize and homogenize procedures and share good practices. Training and education initiatives including seminars, workshops, brainstorming meeting but also student exchanges and support to post-doctorate fellowships is a key point for maintaining and increasing a high expertise level in actinide separation sciences in Europe.
Speaker: Dr Stéphane Bourg (CEA, Nuclear Energy Division, RadioChemistry & Processes Department)
• 7
Targeted Alpha Therapy Research - a Radiochemistry Perspective
One of the greatest challenges in the treatment of different types of cancers is an efficient therapy of occult metastasis. Today chemotherapy is generally employed as an adjuvant treatment to eradicate the minimal residual disease. However, despite that chemotherapy often is a very aggressive method the cancer cells can transform and become resistant towards the chemicals used. This means that the quality of life of the patient is affected in a negative way without resulting in a therapeutic effect. Therefore, new types of treatment for disseminated cancer are of vital importance. One such method is targeted alpha therapy. Targeted alpha therapy utilizes the high energy and short tissue range (50-100 µm) of the alpha particles. This range is orders of magnitude shorter than the beta particle range from other radionuclides widely used within nuclear medicine, such as iodine-131 or yttrium-90, resulting in a significantly higher LET for the alpha particles. This means that if administered to the cancer cells by a tumor specific carrier agent, e.g. an antibody, the alpha emitting nuclide efficiently kills the tumor cell by causing irreparable double strand breaks of the DNA, while sparing the surrounding healthy tissue. This makes the method suitable for treatment of disseminated occult cancers in the form of micro tumors and even single cancer cells. A radioactive nuclide with suitable properties is, however, needed to conduct this type of treatment. The half-life should be relatively short to be able to achieve a high dose and avoid prolonged irradiation in the body but still long enough to be able to perform the radio synthesis and allow for distribution to the target cells. In the same way the daughter nuclides must have a suitable decay pattern. The production route should also be fairly straight forward to ensure availability of the nuclide. One nuclide that fulfils these demands is astatine-211. Astatine-211 is produced using a cyclotron by circa 30MeV alpha particle activation of bismuth-209 through the reaction 209Bi(α, 2n)211At. The half-life is 7.2 hours and the mode of decay is 100% alpha emission along two different routes. Astatine-211 is therefore a promising nuclide for targeted alpha therapy. At Sahlgrenska Academy in Gothenburg, Sweden, radiolabelling research of monoclonal antibodies and polypeptides using astatine-211 has been on-going for almost 20 years. The research is performed within the targeted alpha therapy (TAT)-group that are moving towards phase II/III clinical trials using astatine labelled monoclonal antibodies for patients with disseminated ovarian cancer. This after a successful phase I trial conducted in 2009. The TAT-group is an interdisciplinary group consisting of chemists, physicists, biologists and clinicians from different research centers. Today efforts concerning radiochemistry within the group are directed towards increasing the specific activity of the immunoconjugates, investigating the shelf-life of the prefabricated conjugates before labelling and designing new linker-molecules. There is also a focus on simplifying the chemical production route by automating the radio synthesis.
Speaker: Dr Emma Aneheim (Sahlgrenska Academy at Gothenburg University)
• 12:15 PM
Lunch Marble Hall

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Reitenbergerova 4/95, Mari&#225;nsk&#233; L&#225;zn&#283;, Czech Republic <font color=white>
• Chemistry of Actinide and Trans-actinide Elements 1 Red Hall

### Red Hall

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Reitenbergerova 4/95, Mari&#225;nsk&#233; L&#225;zn&#283;, Czech Republic <font color=white>
Conveners: Prof. Andreas Türler (Paul Scherrer Institute and Bern University), Dr Ladislav Havela (Charles University)
• 8
Gas Phase Chemistry of Superheavy Elements
Gas Phase Chemistry of Superheavy Elements A. Yakushev1 1GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstr. 1, 64291 Darmstadt, Germany a.yakushev@gsi.de Long-lived isotopes of superheavy elements (SHE) beyond Rf, i.e., with atomic number Z ≥ 104 can be produced via fusion reactions between heavy actinide targets and neutron-rich projectiles at a rate of only single atoms per minute (Z=104) or per week (Z=114). Investigating these neutron-rich SHE nuclei using rapid gas-chemical separation and subsequent on-line detection provides an independent chemical characterization and an alternative separation technique to electromagnetic recoil separators. Approaching the heaviest elements, the coupling of chemistry setups to a recoil separator promises extremely high sensitivity due to strong suppression of background from unwanted species. The use of a combination of two separation techniques, physical pre-separation and gas phase chemistry opens the possibility for investigating new compound classes of superheavy elements [1,2]. Electron shells of SHE are influenced by strong relativistic effects caused by the high value of Z. The lighter transactinides with Z = 104-108 were experimentally shown to be members of groups 4 through 8 of the Periodic Table of the elements [3]. Early atomic calculations predicted copernicium (Cn, element 112) and flerovium (Fl, element 114) to be noble gas-like due to the strong relativistic stabilization of the closed-shell configuration 6d107s2 in Cn, and the very large spin-orbit splitting in 7p AOs resulting in the quasi-closed-shell configuration 7s27p1/22 in Fl [4]. Recent fully relativistic calculations studying Cn and Fl in different environments suggest those to be less reactive compared to their lighter homologues in the group, but still exhibiting metallic character [5]. The dilemma whether Cn and Fl are noble gases or rather noble metals calls for experiments. Experimental gas-chromatography studies on Cn have, indeed, revealed a metal-metal bond formation with gold [6]. In contrast to this, for Fl, the unexpected formation of a weak physisorption bond upon adsorption on gold was inferred from first experiments [7]. The recent gas chromatography study on Fl upon the adsorption on gold was performed exploiting clean Fl samples, provided after the pre-separation with the gas-filled separator TASCA [8]. Two Fl decay chains were detected under background-free conditions. The observed behavior of Fl in the chromatography column is indicative of Fl being less reactive than the nearest homolog Pb. The evaluated lower limit of the adsorption enthalpy −ΔHads(Fl) > 48 kJ/mol (95% confidence level) reveals the formation of a metal-metal bond with Au, which is at least as strong as that of Cn, and thus demonstrates the metallic character of Fl [9]. In other experiments, a first molecule of a compound class, which was previously inaccessible for superheavy elements, was recently investigated. The adsorption behavior of Sg(CO)6 was studied by gas-solid chromatography in comparison with that of its nearest homologs in the group, Mo and W [10-12]. References /1/ Ch E. Düllmann et al., Nucl. Instr. Meth. A 2005, 551, 528–539. /2/ Ch.E. Düllmann et al., Radiochim. Acta 2009, 97, 403-418. /3/ A. Türler and V. Pershina, Chem. Rev. 2013, 113, 1237−1312. /4/ K.S. Pitzer. J. Chem. Phys. 63, 1032 (1975). /5/ V. Pershina et al. J. Chem. Phys. 131, 084713 (2009). /6/ R. Eichler et al. Angew. Chem, Int. Ed. 47, 3262-3266 (2008). /7/ R. Eichler et al. Radiochim. Acta 98, 133-139 (2010). /8/ A. Semchenkov et al. NIM B 266, 4153-4161 (2008). /9/ A. Yakushev et al. Submitted to Inorg. Chem., 2013. /10/ J. Even, et al., Inorg.Chem. 2012, 51, 6431-6422. /11/ J. Even, et al. Submitted to Radiochim. Acta, 2013. . /12/ J. Even et al., to be submitted to Science.
Speaker: Dr Alexander Yakushev (GSI Helmholtzzentrum für Schwerionenforschung GmbH)
• 9
Decomposition studies of W and Mo carbonyl complexes and their implications for future experiments with Sg(CO)6
Recent experiments at RIKEN (Japan) showed that Sg carbonyl (Sg(CO)6) can be produced with yields high enough for experimental investigation of its chemical properties [1]. According to theoretical calculations [2], which include so-called relativistic effects, Sg(CO)6 is expected to be slightly more stable than W(CO)6. In this work we aimed at designing an experimental setup for testing this theoretical prediction. Carbonyl complexes of W and Mo, as lighter homologues of Sg, were chosen for testing the setup. Gas-jet systems as well as the detection system used in our work are described in [1]. Two alpha-active tungsten isotopes were produced in fusion-evaporation reactions 144Sm(24Mg,xn)163-164W, while natZn(24Mg,xn)87-88W allowed for formation of β+-decaying molybdenum. The Gas-filled Recoil Ion Separator (GARIS) provided an effective separation of evaporation residues from the beam and from multinucleon transfer reaction products. Evaporation residues were thermalized in a recoil transfer chamber [3], flushed by a He/CO gas mixture. Formed carbonyl products [4] were transported to a decomposition column, held at different temperatures, and bypassed by a column of the same size made of PFA Teflon. Complexes transported through this bypass or the decomposition column were deposited at the low-temperature end of the COMPACT detector [1] according to their adsorption enthalpy and thus provided quantitative information about the production and the decomposition rates, respectively. Obtained results are discussed in the light of future experiments with Sg(CO)6. [1] J. Even et al., in preparation , and A. Yakushev, presentation at this conference. [2] C. S. Nash and B. E. Bursten, J. Am. Chem. Soc. 121, 10830-10831 (1999). [3] J. Even et al., Nucl. Instrum. Meth. A 638, 157-164 (2011). [4] J. Even et al., Inorg.Chem. 2012, 51, 6431-6422.
Speaker: Ilya Usoltsev (Paul Scherrer Institut)
• 10
Towards selenides of the superheavy elements copernicium and flerovium
Transactinide’s chemical behavior is similar to their lighter homologues in the corresponding group of the periodic table. However, with increasing nuclear charges, superheavy elements (SHE) show deviations from the periodicity of chemical properties [1]. An experimentally exceptionally favourable case for comparative studies is the possibility of a simultaneous production of Cn (Z=112) and Fl (Z=114) in Ca-48 induced nuclear fusion reactions with Pu-242 / Pu-244 [2]. Since these superheavy elements are characterized by short half-lives and low production rates, their chemical behavior has to be explored on a single atomic scale. For this purpose gas chromatography is used, allowing for efficient studies of the interaction of volatile gas-phase species with stationary surfaces [1]. Sulphur was chosen as stationary chromatography material for such a comparative studies. In fact, extrapolative predictions, in which thermochemical state functions are correlated mutually, showed that both Cn and Fl may form stable sulfides, and since the stability trends of sulfides formation in group 12 and 14 were predicted to be opposite, FlS was expected to be more stable than CnS. In preparation of the chemical investigations of these superheavy elements, isothermal model experiments with Hg (copernicium homologue) and sulfur surfaces were conducted. Although the formation of HgS(s) is thermodynamically favored (ΔHadsHg(S) < -75 kJ/mol), it was difficult to obtain reproducible results due to the slow interaction kinetics between the sulfur S8 rings (dominant sulfur allotrope at room temperature), and Hg. Recent studies reported amorphous nano-selenium as an efficient mercury sorbent, due to the high affinity of Se towards Hg and the high surface-to-mass ratios of the nanoparticles [3]. Hence, extrapolative predictions for the group 12 and 14 selenide formation were done. Again, stability trends in group 12 and 14 are predicted to be opposite: the formation of FlSe is expected to be favored or at least similar to the homologue selenides, while the interaction between Cn and selenium is expected to be a weak physisorption. The chemical system Hg / Se is an ideal model system to investigate the kinetics and thermodynamics of the adsorption and reaction of a volatile noble metal with selenium surfaces. Hence, first model experiments on the interaction of elemental Hg with red amorphous selenium surfaces, obtained through supercooling of high temperature Se vapors on quartz tubes, were performed. Here, first results from these investigations will be presented. Some conclusions will be drawn, which are important for the preparation of further chemical investigations of Cn and Fl. [1] M. Schädel in “The chemistry of Superheavy Elements” 2-d ed., Springer (2014). [2] Yu.Ts. Oganessian, J. Phys. G: Nucl. Part. Phys. 34, R165 (2007). [3] N. Ralston, Nature Nanotech. 9, 527 (2008).
Speaker: Mrs Nadine Mariel Chiera (Paul Scherrer Institute, University of Bern)
• 11
Production of 261Rf, 262Db, and 265Sg for chemical studies using GARIS at RIKEN
Recently, chemical characterization of superheavy elements (SHEs) with atomic numbers Z ≥ 104 is an extremely interesting and challenging research subject in modern nuclear and radiochemistry [1,2]. At RIKEN, we have been developing a gas-jet transport system coupled to the RIKEN gas-filled recoil ion separator GARIS as a novel technique for SHE chemistry [3–5]. This system is a promising approach for exploring new frontiers in SHE chemistry; (i) background radioactivities originating from unwanted by-products are strongly suppressed, (ii) an intense primary heavy-ion beam is absent in the gas-jet chamber and hence a high gas-jet yield is achieved, and (iii) the beam-free conditions also make it possible to investigate new chemical reactions. In this work, we investigated production and decay properties of long-lived radioisotopes of Rf (Z = 104), Db (Z = 105), and Sg (Z = 106) available for chemical studies [6–9]. Oxygen-18, 19F, and 22Ne beams were extracted from the RIKEN linear accelerator. The isotopes of 261Rfa,b, 262Db, and 265Sga,b were produced in the reactions of 248Cm(18O,5n)261Rfa,b, 248Cm(19F,5n)262Db, and 248Cm(22Ne,5n)265Sga,b, respectively. The evaporation residues of interest were separated in flight from the beam particles and the majority of the nuclear transfer products by GARIS and were guided to a gas-jet chamber at the focal plane of GARIS. The evaporation residues were then thermalized in He gas, attached to KCl aerosol particles, and were extracted through a Teflon capillary to the chemistry laboratory. Alpha and spontaneous fission (SF) decays of 261Rfa,b, 262Db, and 265Sga,b were measured with the rotating wheel apparatus MANON under low background conditions. In the conference, perspectives of the next-generation SHE chemistry opened by GARIS will be also presented. References [1] M. Schädel, Angew. Chem. Int. Ed. 45, 368 (2006). [2] A. Türler and V. Pershina, Chem. Rev. 113, 1237 (2013). [3] H. Haba et al., J. Nucl. Radiochem. Sci. 8, 55 (2007). [4] H. Haba et al., Eur. Phys. J. D 45, 81 (2007). [5] H. Haba et al., J. Nucl. Radiochem. Sci. 9, 27 (2008). [6] H. Haba et al., Chem. Lett. 38, 426 (2009). [7] H. Haba et al., Phys. Rev. C 83, 034602 (2011). [8] H. Haba et al., Phys. Rev. C 85, 024611 (2012). [9] H. Haba et al., Phys. Rev. C (in press).
Speaker: Dr Hiromitsu Haba (RIKEN)
• 12
Excitation functions for production of rutherfordium isotopes in the 248Cm + 18O reaction
Rutherfordium-261 (261aRf; T1/2 = 68s) has been used in chemical studies of element 104, Rf [1]. In recent years, it was reported that there exists a spontaneously-fissioning (SF) isomer (261bRf; T1/2 = 2.6 s) in 261Rf [2-6]. On the other hand, a SF isomer with the similar half-life of 2.1 s also had been reported as 262Rf (T1/2 = 47 ms) [7,8]. It is possible that these two SF isomers are the same and one of these is misassigned. In this work, the excitation functions of Rf isotopes in the 248Cm + 18O reaction were measured to clarify the ambiguity on the assignment of the fissioning isomers in 261,262Rf [9]. Rutherfordium isotopes were produced by bombarding the 248Cm target with an 18O beam supplied from the RIKEN linear accelerator. The beam energies were 88.2, 90.2, 94.8, and 101.3 MeV at the center of the target. A gas-filled recoil ion separator (GARIS) was used to separate the evaporation residues (ERs) in-flight from the incident particles and majority of by-products. ERs were then implanted into a position-sensitive Si strip detector mounted at the focal plane of GARIS. The beam on-off method was applied to measure the decay events of Rf isotopes under low background conditions. At each beam energy, beam on-off periods were set to 6 s-6 s and 0.1 s-0.1 s. The shape of the measured excitation function of 261aRf agreed with the previously reported one [10]. The excitation function of a-few-second SF nuclide exhibited the maximum cross section at 94.8MeV, and the shape of the excitation function was almost the same as that of 261aRf. On the other hand, short-lived SF decays were observed at 88.2 MeV and 101.3 MeV, and they were assigned to 262Rf and 260Rf, respectively. Such the short-lived SF decay was not observed at 94.8MeV. Therefore, we concluded that a-few-second SF nuclide previously assigned to both 261bRf and 262Rf is not 262Rf but 261bRf. References [1] M. Schädel, Angew. Chem. Int. Ed. 45, 368 (2006). [2] S. Hofmann et al., Eur. Phys. J. A 14, 147 (2002). [3] J. Dvorak et al., Phys. Rev. Lett. 97, 242501 (2006). [4] J. Dvorak et al., Phys. Rev. Lett. 100, 132503 (2008). [5] H. Haba et al., Phys. Rev. C 83, 034602 (2011). [6] H. Haba et al., Phys. Rev. C 85, 024611 (2012). [7] L. P. Somerville et al., Phys. Rev. C 31, 1801 (1985). [8] M. R. Lane et al., Phys. Rev. C 53, 2893 (1996). [9] M. Murakami et al., Phys. Rev. C 88, 024618 (2013). [10] Y. Nagame et al., J. Nucl. Radiochem. Sci. 3, 85 (2002).
Speaker: Mr Masashi Murakami (Nishina Center, RIKEN)
• Chemistry of Nuclear Fuel Cycle 1 Mirror Hall

### Mirror Hall

#### Casino Conference Centre

Reitenbergerova 4/95, Mari&#225;nsk&#233; L&#225;zn&#283;, Czech Republic <font color=white>

(1st ASGARD International Workshop)

Conveners: Prof. Christian Ekberg (Nuclear Chemistry, Chalmers), Mrs Václava Havlová (ÚJV Řež, a.s.)
• 13
Experiences of reprocessing plutonium rich mixed carbide fuels
The mixed carbide (70% Pu, 30% U) spent fuel from the Fast Breeder Test Reactor (FBTR) at Kalpakkam, India is being reprocessed at the CORAL facility since 2003. Several campaigns with progressively increasing burnups and reducing cooling periods have been carried out in this facility. Presently spent fuels with a burn up of 155 GWd/Te with cooling periods as around two years are being reprocessed. The satisfactory operation of this facility has provided valuable inputs for the design of process, equipment and other systems. Sustained operation of critical process equipment such as chopper, dissolver and solvent extraction equipment enabled in the fine tuning of design for reliable operation and easier maintenance. Design optimization for the future plants DFRP and FRP which are under construction for closing the fuel cycle of FBTR and Prototype Fast Breeder Reactor (PFBR) respectively could be carried based on the operating experience with single pin chopper. The apprehension that mixed carbide fuel would be difficult to dissolve and not give a satisfactory solvent extraction performance, is alleviated by the experience of quantitative dissolution and recovery of plutonium. Typical hull losses have been experimentally found to be less than 0.08% for plutonium. Though some carbide carbon was found to be there in the dissolver solution, it does not affect the solvent extraction performance. The highly oxidative dissolution conditions required for the dissolution of the spent fuel, call for material of construction other than the conventional stainless steel, as its corrosion rate of under such condition is unacceptably high. Alternate material of construction has been identified and deployed for the CORAL dissolver. Inspection of the dissolver after around three years of operation has revealed satisfactory performance. Though three solvent extraction cycles have been provided in the plant, it has been found that the required decontamination could be achieved with a single cycle. Typical decontamination factors of greater than 10**3 for Ru-106 and 10**4 for Cs-137 have been achieved. The recovery of plutonium and uranium are greater than 99.9% and 99.8% respectively. The centrifugal extractors have provided extremely satisfactory performance with progressive improvement in the performance in terms of reduced maintenance requirements with incorporation of design changes during the campaigns. R&D work has been concurrently taken up based on the performance evaluation of the facility for improving the recovery, decontamination factors, economy and reducing the waste volumes. With the computer code PUSEP(Ver-II) developed by the reprocessing group, IGCAR, an innovative extraction flowsheet is formulated to meet the decontamination requirements of both 95Zr and 106Ru while reprocessing fuels with less than two years cooling period. With this code it has been possible to establish the flow rate controls required for avoiding the third phase formation due to excessive plutonium loading in the solvent phase. Also, it has been found that closer to the stoichiometric requirement of uranous for separation of plutonium from uranium is possible. These findings will substantially reduce the number of solvent extraction cycles and hence the waste volumes. Reduction of solvent waste using vacuum distillation and the removal of dissolved organic by diluent wash using efficient contactors to address the red-oil formation during waste evaporation, are a few R&D activities in progress to improve the plant performance. Another important offshoot of the operation of the CORAL facility is the development of a variety of hot cell equipment and systems for remote operation and maintenance with least plutonium contamination in the operating area. Based on the satisfactory experience, it is expected that the reprocessing of PFBR spent MOX fuel would not pose a challenging problem as the plutonium content in PFBR is much less (around 25%).
Speaker: Dr Natarajan Rajamani (Indira Gandhi Centre for Atomic Energy)
• 14
Dissolution of carbide fuel materials
As part of the strategic research agenda for sustainable nuclear energy in Europe [1], carbide fuel is proposed as a potential candidate fuel for sodium cooled fast reactors and is the fuel of choice for gas cooled fast reactors. Carbide fuels have also been demonstrated to achieve high burn-up (> 155 GWd/t) in the sodium cooled Fast Reactor Fuel Reprocessing technology being pursued at the Indira Gandhi Center for Atomic Research (IGCAR), Kalpakkam. There are a number of issues that need to be addressed in the reprocessing of carbide fuel in order to demonstrate a sustainable closed nuclear fuel cycle. Carbide fuel can be problematic when applying the traditional PUREX reprocessing technology of solvent extraction from a nitric acid solution. The dissolution of uranium carbide (UC) in hot nitric acid can lead to the formation of soluble organic molecules that can interfere with the extraction of uranium and plutonium reducing their extraction and recovery efficiencies. The organics can also lead to emulsions causing difficulties within industrial processes. Even when the U and Pu have been removed from the soluble organics the remaining liquor contains highly radioactive fission products in the presence of organic material that requires volume reducing before immobilising in a glass matrix. The presence of organics can present a safety issue and needs to be effectively managed. In this paper we present the dissolution results from first titanium carbide (a potential barrier material in GCFRs) and then from unirradiated uranium carbide fast reactor blanket fuel pellets. The kinetics of dissolution will be discussed together with comments on the organic materials produced and carbon mass balance. [1] SNETP Strategic Research Agenda May 2009; Strategic Research and Innovation Agenda, Feb 2013.
Speaker: Mr Chris Maher (National Nuclear Laboratory)
• 15
Dissolution of Mo-based CERMET fuel: ESI-TOF MS Speciation in nitric acid medium
The main long term contributors to spent fuel radiotoxicity are plutonium followed by the minor actinides (MA = Np, Am, and Cm). A possibility to reduce the radiotoxic inventory and the footprint of the repository is to separate the most radiotoxic and long-lived elements from spent fuel and to transmute them into nonradioactive elements or elements with a much shorter lifetime. For the transmutation in accelerator-driven systems (ADS) fuels with a high content of Pu and MA are preferred. To increase the burn-up of transuranium elements (TRU) and to reduce the formation of new TRU inert matrix fuels (IMF) [1-3] are favored. These are ceramic substrates or metallic matrices with high thermal conductivity, which are free of uranium and also have small cross sections for reactions with neutrons. The reprocessability of (Pu,MA)-oxide within a metallic 92Mo matrix (CERMET) is under investigation within the EU project ASGARD [4]. Dissolution in nitric acid is the first step in reprocessing. Therefore, detailed knowledge of the speciation of molybdenum in nitric acid medium is crucial on the one hand to understand this dissolution process and on the other hand as a basis for the design of a tailored extraction process. The speciation of molybdenum has been studied intensively in hydrochloric and perchloric acid medium[5,6], but little is known about the speciation in nitric acid medium, especially at high acidities, which are relevant for the dissolution of IMF. The solution species of molybdenum in strongly acidic nitric acid medium need to be extensively characterized and quantified. Therefore, electrospray ionization mass spectrometry, which can probe the stoichiometry and relative abundances of solution species, was applied. Here, we present new experimental data on the speciation of molybdenum as a function of nitric acid concentration. Isotopically pure 98Mo powder was dissolved in nitric acid and measured with the ALBATROS ESI-TOF [7]. Monomeric, dimeric, trimeric, tetrameric, and pentameric cationic molybdenum species have been detected. Besides the presence of hexavalent Mo species the spectra show that pentavalent Mo species are present in solution in spite of the oxidizing condition in strong nitric acid. 1. Haas, D., et al., Energ Convers Manage, 2006. 47: p. 2724-2731. 2. Ouvrier, N. and H. Boussier, Procedia Chemistry, 2012. 7: p. 322-327. 3. Degueldre, C., J Alloy Comp, 2007. 444: p. 36-41. 4. http://asgardproject.eu/. 5. J. J. Cruywagen, J. B. B. Heyns, Polyhedron 2000, 19, 907-911. 6. P. Tkac and A. Paulenova, Separ Sci Technol, 2008, 43, 2641. 7. T.Bergmann et al., Rev. Sci. Instrum., 1989. 60: p. 347.
Speaker: Ms Elena Laura Ebert (Forschungszentrum Jülich GmbH IEK-6)
• 16
Radionuclide distribution in corrosion layers of historic radioactive waste of NPP A1
The radioactive waste management in Slovak Republic complies with the waste acceptance criteria for repository of Slovak Republic. The essential criterion is a declaration of radionuclides disposed in waste packages. The group of 19 limited radionuclides comprises various gamma, beta and alpha radionuclides. The activity of alpha radionuclides is monitored as a total alpha radioactivity, the limit for the total alpha activity per one waste package is 400 Bq.g-1 in average, or a local activity and then the local limit is 4000 Bq.g-1, which is usually applied for the smallest produced unit of a RAW (200L drum, 60L drum, or compacted product after high-pressure compacting). Legacy radioactive wastes treated during D&D of NPP A1 represent greater amount of conditioned RAW disposed in the repository. Nuclear power plant A1 was shutdown after an INES 4 accident in 1977, when one of fuel assemblies had melted down in a reactor channel. Any kind of deactivation process had not been applied since shutdown of NPP and basically all deactivation and pre-decommissioning works have started in 90’, and therefore there were lot of possibilities for corrosion of contaminated materials. This corrosion impacts also more than 300 pieces of casks used for spent fuel assemblies storing. Cladding defections and also deformations caused by incorrect storage conditions caused other cladding defects, which led to massive contamination of spent fuel casks. Outer and inner surface of casks is contaminated mainly by 137Cs, 90Sr and alpha RN (241Am and Pu isotopes). According to the pre-disposal measurements by alpha scanner fragmented casks cannot be disposed without treatment because of exceeding limit for total activity of alpha RN. The paper describes analyses performed with samples taken from inner surfaces of fragments of spent fuel casks to prove that contamination is only in a corrosion layer and not in core material of casks (carbon steel). This proof would help to enhance waste management of spent fuel casks. Determination of alpha isotopes by alpha PIPS spectrometry and determination of gamma emitting radionuclides by gamma spectrometry is described. Separation of 241Am and Pu isotopes 238,239,240Pu was carried out by means of extraction chromatography with TRU-resin sorbent. The depth distribution of contamination was performed on the assumption that during electrochemical sampling with identical conditions same amount of iron will be taken. After determination of iron concentrations by AAS it was possible to calculate thickness of corrosion and subsequently calculate depth distribution of radionuclides in several layers of corrosion. These data should help to enhance process of managing legacy metallic RAW from NPP A1.
Speaker: Mr Boris Andris (VUJE a.s.)
• 17
Study on sorption and diffusion of Sr in crushed and intact basalt and granite investigated in column method
This study investigates sorption and diffusion of Strontium (Sr) in two potential host rocks (granite from Kinmen Island and basalt from Penghu Island) by using batch and through-diffusion methods in order to establish a reliable safety assessment methodology. These methods were applied to crushed and intact rock samples to investigate the actual geological environment. According to solid-phase analysis, including X-ray diffraction, elemental analysis, auto radiography, and polar microscopy, the sorption component primarily contained iron–magnesium (Fe–Mg) minerals in basalt and granite. Moreover, the distribution coefficient (Kd) of Sr in various concentrations (~10−2–10−7 M) obtained from batch tests indicated a higher sorption capacity in basalt than that in granite because of the 10% Fe–Mg mineral content. The diffusion of Sr both in granite and basalt reach steady state after 100 days and apparent diffusion coefficient (Da) were 3.29×10-11 m2/s (for Sr in crushed granite), 4.17×10-12 m2/s (for Sr in crushed basalt), respectively. However, diffusive result (Da) of Sr in intact rocks was estimated a lower value than those obtained using crushed rocks. According to the diffusive results in crushed and intact rocks, it showed that major retardation of Sr depended on the microporous structure of tested media, such as decreases of constrictivity (δ) and increases of tortuosity(τ). In fact, the solid/liquid (S/L) ratio decreased as is the case when switching from batch to column experiments and the sorption effect on minerals became even more negligible in retardation of radionuclide migration.
Speaker: Prof. Ming-Chee Wu (Department of Earth Sciences, National Cheng Kung University, Tainan, Taiwan)
• 3:00 PM
Coffe Break Marble Hall

### Marble Hall

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Reitenbergerova 4/95, Mari&#225;nsk&#233; L&#225;zn&#283;, Czech Republic <font color=white>
• Nuclear Analytical Methods 1 Mirror Hall

### Mirror Hall

#### Casino Conference Centre

Reitenbergerova 4/95, Mari&#225;nsk&#233; L&#225;zn&#283;, Czech Republic <font color=white>
Conveners: Dr Jan Kučera (Nuclear Physics Institute), Prof. Xiaolin Hou (Technical University of Denmark, Center for Nuclear Technologies)
• 18
Biochemical neutron activation analysis (BNAA) in pre- and post-genomic era of proteomics and metabolomics
Neutron activation analysis (NAA) is a well-established analytical technique for the simultaneous measurement of multielement concentrations. The most common forms of NAA are instrumental (INAA), radiochemical (RNAA) and preconcentration (PNAA). We have previously reported the development of speciation NAA (SNAA). We are also interested in the development of biochemical NAA (BNAA) methods for the separation, purification, characterization, and measurement of metalloproteins and organic compounds containing trace elements which are of biological/biochemical importance. We take advantage of the unique features of both techniques. For example, we need an analytical technique capable of analyzing a few milligrams of solid as well as liquid samples non-destructively and independent of chemical species, and of determining trace levels of several elements simultaneously within a short time in a matrix largely composed of carbon, hydrogen, nitrogen, oxygen and sulfur. Of course, the technique should provide excellent precision, accuracy, sensitivity, and detection limits. NAA meets all of these requirements. The biochemical techniques of interest are dialysis, ammonium sulphate precipitation, gel filtration, ion exchange and hydroxyapatite chromatography, high-performance liquid chromatography, chromatofocusing, isoelectrofocusing, isotachophoresis, sedimentation equilibrium and enzymatic assay. We called this combination of two techniques BNAA which is ideally suited for studying metalloproteins, protein-bound trace elements, and organometallic compounds. We observed that most of the trace elements in bovine kidneys, for example, were largely concentrated in the cytosol fraction. More than 70% of As, Br, Cl, Co, K, Na and Rb, about 65% of Cd, and 30-35% of other elements except Se (14.4%), Cr (15.6%) and Mo (24.6%) were detected in this fraction. Elements such as Ca, Cr, and Se were more abundant in the nuclei fraction with concentrations of 34%, 75% and 73%, respectively. The dialysis experiments showed that more than 90% of Ca, Cd, Cu, Fe, Mg, Mn, Mo, Se, V and Zn, and possibly As, and I, and about 20% of Br were bound to macromolecules, mainly proteins. Most of these proteins were stable in the pH range of 3.5 to 10.5. We separated and purified several metalloprotein species. Examples of these species with particular emphasis on Se will be presented.
Speaker: Prof. Amares Chatt (Dalhousie University)
• 20
Measurement of selenium levels in cultivated Japanese and Korean oysters and Japanese rock oysters using the 17.4-s neutron activation product 77mSe
Oysters in Japan are mainly cultivated in Miyagi, Hiroshima, and Hokkaido Prefectures. Sometimes baby cultivated oysters are exchanged between Japan and Korea; so both cultivated oysters are said to be genetically similar. Since Japanese consume a fair amount of raw oysters, it is of interest to compare the elemental levels of oysters from different areas. Soft tissues of cultivated Japanese oysters (Miyagi Prefecture, 2004 Nov, at 1, 6 and 11 m depths), Korean oysters (Koje-do and Kosong in Busan, 2002 Oct, 2004 Jan, and 2005 Dec), and Japanese rock oysters (Honshu Island) were analyzed for selenium levels. The soft tissues, namely hepatopancreas, gill, muscle, and mantle were separated, freeze-dried, pulverized, and analyzed by an instrumental neutron activation analysis (INAA) method in conjunction with Compton suppression spectrometry (INAA-CSS). The method consisted of irradiation of samples for 12 s in a neutron flux of 5x1011 cm-2s-1 using the rapid cyclic pneumatic sample transfer system at the Dalhousie University SLOWPOKE-2 reactor (DUSR) facility, decay for 15-20 s, and counting for 60 s. The 161.9-keV gamma-ray of the 17.4-s nuclide 77mSe was used for assaying selenium. The method was validated using NIST, NRC and NIES certified reference materials. An absolute detection limit of 0.15 µg selenium using NIST SRM 1566b Oyster Tissue was achieved. Selenium levels between Japanese and Korean oysters did not show much difference. The selenium concentrations in Japanese rock oysters showed the following trend: gill > hepatopancreas > mantle > muscle.
Speaker: Dr Michiko Fukushima (Ishinomaki Senshu University)
• 21
Comparison of INAA and LC-ICP-MS for the determination of As species in marine tissues
The aim of this work was to acquire traceable quantitative results for total As in whole samples as well as in extracts containing As species. Instrumental neutron activation analysis (INAA) is well suited for such measurements and is used in this work to validate the As mass fraction determined by liquid chromatography combined with inductively coupled plasma mass spectrometry (LC-ICP-MS) in tuna fish and kelp candidate RMs and other marine samples, including certified RMs. INAA was used to determine total As and trace elements in original solids, extracted solids, and in extracts as well as LC fractions; LC-ICP-MS was limited to the determination of As species in extracts. Extraction yields were determined by INAA for a number of common solvents and extraction techniques; the best results were acquired after methanol/acetone/water extraction with sonication. This procedure was used for quantitative As species evaluation with LC-ICP-MS incorporating internal standards and single point standard addition, while the sum of all As fractions was monitored by INAA. In the case of tuna tissue, AB was the predominant species determined by LC-ICP-MS and its As mass fraction was 4.41 ± 0.09 mg/kg. The total extracted As by INAA was 4.88 ± 0.27 mg/kg. In case of the BCR 627 certified RM the sum of AB + DMA was 4.15 ± 0.10 mg/kg, measured as AB = 3.99 ± 0.08 mg/kg and DMA = 0.148 ± 0.010 mg/kg in good agreement with the certified values, and the total As extracted was 4.28 ± 0.18 mg/kg by INAA summing up with As in the residue to 4.75 ± 0.17 mg/kg in excel-lent agreement with 4.81 ± 0.11 mg/kg determined by INAA in the original material. These differences between the techniques may be explained by relatively too high dissolution required by LC-ICP-MS not detecting very low mass fractions of other species in the extracts, and/or retention of As on the column. To completely evaluate the LC-ICP-MS process INAA detection limits were lowered utilizing the Compton suppression technique in the gamma spectrometry to reach below 0.2 ng sensitivity, which is sufficient to determine As in LC effluent fractions. LC effluent fractions were collected according to the time intervals recorded by the ICP-MS, reduced in volume, and transferred and dried on Whatman 542 filter substrate. These were subsequently submitted to INAA. The initial results showed As in the background (blank) fractions of the chromatogram, however most of it due to solvent blank. Arsenic in these fractions is not captured by ICP-MS and thus would explain the difference. Further, the quantitative determination of As by INAA in the chromatogram peaks provided a direct measurement of each separated species and allowed for calibrated determination of each species. Species, including those not available as standards, e.g., the arsenosugars found in kelp, can be accurately determined by INAA and used as calibrants. INAA and LC-ICP-MS thus were successfully used as complementary techniques for characterization and traceability studies related to the development of RMs for As species.
Speaker: Dr Rolf Zeisler (National Institute of Standards and Technology)
• Separation Methods, Speciation 1 Red Hall

### Red Hall

#### Casino Conference Centre

Reitenbergerova 4/95, Mari&#225;nsk&#233; L&#225;zn&#283;, Czech Republic <font color=white>

(session dedicated to the memory of prof. Věra Jedináková-Křížová)

Conveners: Andreas Geist (Karlsruhe Institute of Technology (KIT)), Dr Mojmír Němec (CTU FNSPE, Department of Nuclear Chemistry)
• 22
Complexation and Extraction of An(III) and Ln(III) with water-soluble SO3-Ph-BTBP
The recycling of minor actinides as nuclear fuel is complicated by the presence of curium due to its short term thermal power and neutron dose rate. Thus the development of processes for separating americium from curium are of particular interest. A new system was developed to separate only americium, addressing some of the challenges with the EXAm process such as a narrow pH window. The so called AmSel process uses water soluble SO3-Ph-BTBP and TODGA’s for Am(III), Cm(III), and Ln(III) separation. Am(III) + Cm(III) + Ln(III) distribution ratios as a function of HNO3 and SO3-Ph-BTBP concentrations were determined in extraction experiments. At low nitric acid concentrations the separation factor of Am(III) over Eu(III) exceeded 1000 and decreased with increasing acid concentration. The formation of 1:2 An(III)- and Ln(III)-aq-BTBP complexes was proven by time-resolved laser fluorescence spectroscopy (TRLFS) investigations of the aqueous phase after extraction. Furthermore, separation factors of Am(III) and Cm(III) for the aq-BTBP/TODGA system were determined at various experimental condition, varying between 1.5 and 3.2. The extraction studies revealed that stripping Am(III) from a loaded TODGA solvent is not impeded by slow kinetics. Buffers or salting out agents are not required. For a better understanding of the selectivity of SO3-Ph-BTBP towards An(III) over Ln(III) the complexation of Cm(III) and Eu(III) with SO3-Ph-BTBP was studied by time-resolved laser fluorescence spectroscopy (TRLFS). Conditional complex formation constants of the 1:2 An(III) and Ln(III) complexes were determined at pH 3 and in 0.5 mol/L HNO3. Though the stability constants of the 1:2 An(III) and Ln(III) complexes at 0.5 mol/L HNO3 were lower than at pH 3 by several orders of magnitude, the difference in the stability constants of two orders of magnitude between Cm(III) and Eu(III) remained constant. These results are in excellent agreement with the selectivity determined in the extraction studies and proves that the selectivity of SO3-Ph-BTBP towards An(III) over Ln(III) is preserved even at highly acidic conditions. Furthermore, to explain the significant decrease of the stability constants of the 1:2 An(III) and Ln(III)-SO3-Ph-BTBP complexes at 0.5 M HNO3, fundamental studies on the impact of different parameters such as ionic strength, nitrate complexation and protonation of the ligand were performed. These studies revealed valuable mechanistic information on complexation reactions including the impact of competing reactions and/or ionic strength effects at various experimental conditions.
Speaker: Prof. Petra Panak (University of Heidelberg)
• 23
Separation of Minor Actinoids(III) over Lanthanoids(III) by BTBP or BTPhen Extracting Compounds
Different extraction systems for the separation of trivalent minor actinoids over lanthanoids were studied during last years. The CyMe4-BTBP and its derivatives have been demonstrated to be prospective extractants for the solvent extraction of minor actinoids over lanthanoids from high-level liquid waste issuing the reprocessing of irradiated nuclear fuel (the r-SANEX process). The presentation will be focused on different effects of 1,2,4-triazine extracting compounds and diluents on extraction systems properties. The results of testing the CyMe4-BTBP ligand and its new derivatives (such as Cy5-S-Me4-BBP, Cy5-O-Me4-BTBP, MeCyMe4-BTBP or t-BuCyMe4-BTBP) for the separation of Americium(III) over Europium(III) from HNO3 solutions and influence of the used diluents (both polar and non-polar) will be discussed. Moreover, complexing properties of several novel hydrophilic ligands, such as (PhSO3Na)2-BTBP, (CH2NMe3)2-BTBP or (PhSO3Na)2-BTPhen will be described as prospective agents for i-SANEX process. In addition to the dependences of Americium(III) and Europium(III) distribution ratio values and their mutual separation factor values on HNO3 concentrations, the results of the thermodynamic and kinetic studies will be presented.
Speaker: Mr Petr Distler (CTU in Prague)
• 24
Actinide stripping by a hydrophilic BTP ligand in aqueous HNO3 from TODGA-containing organic phase
N,N,N′,N′-tetraoctyl-diglycolamide (TODGA) is broadly studied as a non-specific extractant for actinides and lanthanides from HNO3 solutions of nuclear waste, in particular for group actinide extraction (GANEX process). Geist and his coworkers proposed a novel hydrophilic ligand, 2,6-bis(5,6-di-(sulfophenyl)-1,2,4-triazin-3-yl)pyridine (SO3-Ph-BTP) for selective stripping of actinides(III) from the loaded organic phase [A. Geist et al., Solvent Extr. Ion Exch., 30, 433 (2012)], and determined (by TRLFS) the stability constants of its consecutive (from 1:1 to 1:3) complexes with Cm(III) and Eu(III) in aqueous solutions [C.M. Ruff et al., Dalton Trans., 41, 14594 (2012)]. In the present work, we studied the distribution of some actinides(III-VI) in the two-phase systems: TODGA (in kerosene) / SO3-Ph-BTP (0–100 mM in aqueous HNO3); and determined the apparent stability constants of their complexes in the aqueous phase, based on the distribution ratios of the metal ions. The effect of protonation of the SO3-Ph-BTP ligand in the acidic solutions was discussed. This work was financed from the National Centre for Research and Development through the Strategic Program Technologies Supporting Development of Safe Nuclear Power Engineering, task 4: Development of spent nuclear fuel and radioactive waste management techniques and technologies.
Speaker: Mr Łukasz Steczek (Institute of Nuclear Chemistry and Technology)
• 25
Various Flowsheets of Actinides Recovery with Diamides of Heterocyclic Carboxylic Acids
Various neutral ligands are studied as potential ligands for separation of actinides from lanthanides. The most effective extractants for selective recovery of actinides from high level wastes are poly nitrogen compounds. The presence of several “soft” donor atoms in ligand structure allows to reach very high Am/Eu separation factor values. Recently a new class of neutral polydentate compounds – diamides of heterocyclic dicarboxylic acids – was proposed for recovery of f-elements from nitric acid. Ligands belonged to this class possess in their structure both “hard” oxygen and “soft” nitrogen atoms. Such combination of coordination centers provides high extraction ability of ligand toward f-elements and better affinity to actinides than lanthanides. Diamides of 2,6-pyridine-dicarboxylic acid, diamides 2,2'-dipyridil-6,6'-dicarboxylic acid, diamides of 6,6’’-(2,2’:6’,2’’-terpyridine)dicarboxylic acid, amides of 1,10-phenanthroline-2-carboxylic acid and diamides of 1,10-phenanthroline-2,9-dicarboxylic acid were synthesized and tested for extraction of actinides (III, IV, V, VI) and lanthanides (III) from nitric acid solutions. In our work we studied extraction properties of diamides of 2,6-pyridine-dicarboxylic acid (DPA) and diamides 2,2'-dipyridil-6,6'-dicarboxylic acid (Dyp). DPA effectively extract actinides (III, IV, VI) and lanthanides (III) from nitric acid solutions. Actinides are extracted better than lanthanides. The Am/Eu separation factor up to 6 for extraction from 1-2 M HNO3 can be reached. Solutions of DPA in polar fluorinated diluents have very high loading capacity on extracted metals and can be used for recovery of actinides from wasted with high lanthanides content (more than 17 g/L) Dyp have in their structure two pyridine rings and are more selective extractants than DPA. Americium can be selectively extracted from lanthanides with separation factors more than 10. In the present work two flowsheets for actinides recovery and separation them from lanthanides on the base of DPA and Dyp were developed. Both schemes were tested in laboratory scale using simulate solutions of raffinates with high content of fission products.
Speaker: Dr Mikhail Alyapyshev (Khlopin Radium Institute)
• Poster Session - Nuclear Analytical Methods
• 26
90Y Cherenkov radiation measurement for 90Sr determination
Isotope of strontium 90Sr (one of the nuclear fission products with half-life 28.9 years) is well known for its biochemical similarity with calcium and possible consequent incorporation into human body. Main risk presents its daughter product 90Y (half-life 64.1 hours), which is a high energy β-emitter (Eβ,max=2.28 MeV). That is why the development of fast and effective method of 90Sr determination or monitoring is ongoing last 50 years and it is still one of the important topics. Hence, current demands call for advanced and less time-consuming methods for 90Sr determination. Main aim of this research was focused on the 90Sr determination in simulant solutions of environmental samples without the necessity to wait for the equilibrium with 90Y. This approach is crucial for the development of rapid method of 90Sr determination in environmental samples. Activity of 90Sr was measured through its daughter product 90Y using Cherenkov counting on HIDEX 300 SL and TRIATHLER (both Hidex Oy, Finland) liquid scintillation counters. Two type of samples were used for measurement. The Cherenkov radiation was measured from samples containing equilibrium amount of 90Y or from samples where 90Y growth is observed. A set of solutions with different diffraction indexes and set with different wavelength shifters for increasing Cherenkov radiation yield/detection was studied. It was find out that composition of the solution strongly affects measured background and hence further optimization of the sample content and parameters measurement is necessary. The activity obtained via Cherenkov counting were compared and verified using liquid scintillation counting of 90Sr, similar comparison was done between Triathler (1-photomultiplier) and HIDEX 300 SL (3-photomultipliers, TDCR) measurements.
Speaker: Mr Soběslav Neufuss (CTU in Prague)
• 27
A Comparison of expanded uncertainties for measuring iodine levels in nutritional materials by pseudo-cyclic epithermal INAA-AC using single comparator and k0 methods
A combination of different types of instrumental neutron activation analysis (INAA) technique was developed for the determination of iodine in various food items from Ghana [1]. The methods involved conventional INAA, epithermal INAA (EINAA), pseudo-cyclic INAA (PC-INAA) and pseudo-cyclic EINAA (PC-EINAA) in conjunction with conventional and anti-coincidence (AC) gamma-ray spectrometry using both single comparator and k0 standardization methods. The uncertainties associated with these methods were evaluated following ISO GUM procedures. The trueness of the methods were checked by analyzing several reference materials (RM) and standard reference materials (SRM) provided by the U.S. National Institute of Standards and Technology (NIST). Our results were in good agreement with the certified values. The expanded uncertainties associated with the measurement of iodine levels in NIST RM 8415 Whole Egg Powder by a PC-EINAA-AC method using the single comparator and k0 standardization procedures will be presented. The expanded uncertainty (κ = 2, ~95% CL) of 1.81 ±0.48 was obtained for the k0 procedure compared to that of 1.85 ±0.22 for the single comparator procedure. The value for the k0 procedure appears to be slightly influenced by the uncertainties in the nuclear constants and detector full photopeak efficiency determination. Reference 1. B.J.B. Nyarko, Ph.D Thesis, University of Cape Coast, Cape Coast, Ghana (2007)
Speaker: Prof. Amares Chatt (Dalhousie University)
• 28
A new formulation of effective states of “atoms in compounds”. application to study hyperfine structures and chemical shifts of x-ray emission lines.
Concepts of oxidation number state of an atom in a molecule and related theories are extremely useful in chemistry. At the same time, a good (clear and unambiguous) definition of the state of an atom in a molecule does not exist. Various methods of determining it from calculations lead to different results [1]. Each of known definitions has its drawbacks. The methods based on the use of one-electron density matrices (Mulliken or Löwdin populations analyses, etc.) are basis set dependent. The methods that use the electron densities (Bader or Hirschfield charges, Voronoi cells), suggest introduction of some complementary (artificial) notions or partitioning a molecule (solid) on regions in a manner that is not arising from any of physical principles. There is a number of experimentally observed properties of compounds, depending on a distribution of the valence electron densities or their changes in the atomic core regions. They include chemical shifts of X-ray emission spectra [2], hyperfine structure constants, isotope (volume) shifts, etc. Earlier our group has developed a two-step method to calculate these properties through first-principle based electronic structure calculations within the generalized relativistic pseudopotential approximation followed by a posteriori restoration of the information on the wave functions in the atomic core regions that is missed in the results of pseudopotential calculations [3]. On the basis of this two-step method one can formulate an approach for determining the state of an atom in a molecule (compound). A radius Rc of the core region is determined by the smallness of interaction of valence electrons located within a sphere (r < Rc) with the external (chemical) environment (r > Rc) compared to their interaction with the nucleus and core electrons of a considered atom. Using the properties of proportionality of valence spinors in the atomic core region with the radius Rc [4], one introduce some new terms: "charges of partial waves" for valence electrons in the core region, "reduced population numbers" and one-center density matrices "reduced on the radial quantum number nr". It is shown that the above-discussed properties characterized by the state of an atom in a compound rather than by chemical bonds are well described by only these terms. Results of calculations of the properties of atoms and molecules are presented. The work is supported by the SPbU Fundamental Science Research grant from Federal budget #0.38.652.2013 and RFBR grant #13-03-01307-a. 1. C.J.Cramer, Essentials of Computational Chemistry: Theories and Methods, (2002,Wiley). 2. Y. V. Lomachuk and A. V. Titov, Phys. Rev. A 88, 062511 (2013). 3. Titov A.V. et al., Int. J. Quant. Chem., 104(2), 223 (2005). 4. Titov A.V., Mosyagin N.S., Int. J. Quant. Chem., 71(5), 359 (1999).
Speaker: Yuriy Lomachuk (Petersburg Nuclear Physics Institute, Gatchina, Russia; Dept. of Physics, St. Petersburg State University, Petrodvoretz, Russia)
• 29
A simple determination of 41Ca by ICPMS in concrete samples as a tool for the decommissioning of nuclear facilities
In October 2011 the European Joint research Project MetroRWM – Metrology for Radioactive Waste Management of the European Metrology Research and Program (EMRP) began, with a total duration of three years. One of the objectives of this project is to develop new measurement methodologies for the assessment of radioactive waste, focusing its attention on waste packages containing solid low and intermediate level radioactive waste consigned to near-surface or geological repository. In the decommissioning of shielding concrete from nuclear facilities, the radionuclides of interest include 41Ca, 55Fe, 60Co, 63Ni, 133Ba and transuranics. Calcium-41 is of particular interest, due to its ubiquity in reactor bioshields, its bone-seeking chemistry and its radiotoxicity if ingested. Among these radionuclides gamma emitters can be easily determined using gamma-spectrometry. However for the determination of beta and alpha emitters, such as 41Ca, the radionuclides need to be separated individually from matrix and other radionuclides before being measured. Calcium-41 is a long-lived radionuclide produced by neutron activation in the concrete shield around the reactor, 40Ca (n,γ) 41Ca and displays high mobility in the environment and as well bone-seeking bioavailability. Calcium-41 decays to the ground state of 41K by pure electron capture, emitting X-rays and Auger electrons of very low energy (0.3-3.6 keV). Measurement by X-ray spectrometry is challenging due to the relatively low detection efficiencies encountered in this technique, the low abundance of X-rays from 41Ca (11.4 % for 3.31 keV X-ray) and the possibility of severe interferences produced by other beta-gamma radionuclides with similar energy. It can be measured by liquid scintillation but the procedure is time-consuming because all other radionuclides have to be removed due to the poor energy resolution of beta spectra and the low energy of its X-rays and Auger electrons. Mass spectrometry techniques such as accelerator spectrometry (AMS) and resonance ionization mass spectrometry (RIMS) have also been used for the 41Ca determination but both of these techniques are expensive and not easily available for the routine analysis. The aim of this paper is to describe a rapid and reliable method for the determination of 41Ca in concrete samples by ICPMS, overcoming the complex and time consuming chemical separation of 41Ca from the matrix. Samples are firstly ground and fused with LiBO2 and Li2B4O7 (in the presence of ~0.5% LiBr) and then dissolved in dilute acid. Then silicates are removed by means of PEG-precipitation. The acid solution can be analyzed directly, using the reaction cell mode, in order to avoid the polyatomic and isobaric interferences. Preliminary recovery tests using solutions of known concentrations of K and Ca were performed. The average recovery is 101.3% with a relative standard deviation of 3.2 % showing the method has good reproducibility
Speaker: Dr MAURO CAPONE (ENEA)
• 30
Accelerator mass spectrometry of uranium: comparison of U<sub>3</sub>O<sub>8</sub> and UF<sub>4</sub> target matrices
For determination of 236U/238U ratios in environmental samples by accelerator mass spectrometry, the U3O8 targets are usually used for the UO- beam production. Uranium fluoride targets containing no oxygen and hydrogen may offer higher molecular isobar suppression together with a higher accuracy and sensitivity of uranium isotope analysis1. However, the preparation of anhydrous UF4 targets is more complicated than the preparation of U3O8 targets. When introducing inert atmosphere into the dehydration step of the preparation the only partial reduction of oxygen and hydrogen content in the final product of the preparation method was assured. In this work, several U3O8 and UF4 targets were tested in the CENTA laboratory using the MC-SNICS ion source and double focusing injection magnet and the targets were prepared using the Vienna KKU standard with 236U/238U isotopic ratio of 10-11. The detailed study of anhydrous UF4 preparation method will be performed in CTU laboratories. The ion current from only one UF2- sample was in average higher by about 50 % than the UO- current from the U3O8 samples. The targets were completely sputtered away, and the estimated ionization yields of UO- and UF2- were of the order of 10-3. However, with the improved procedure of the UF4 targets production, we expect that even higher ionization yields could be obtained. REFERENCES 1. Wang X.: Nucl. Technol., 2013(182), 235.
Speaker: Irena Špendlíková (Department of Nuclear Chemistry, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University, 115 19 Prague, Czech Republic)
• 31
Americium winning for its determination in boric-acid containing NPP evaporator concentrate
The aim of this research was to develop a method for pre-concentration of americium from operational radioactive waste for its determination. In these experiments, the attention was paid to separation of americium from boric acid containing evaporator concentrate coming from the Dukovany Nuclear Power Plant by an extraction chromatographic system, where extraction agent used was N,N,N’,N’-Tetraoctyl Diglycolamide (TODGA) incorporated in polyacrylonitrile (PAN) matrix. For the elution of retained americium, the oxalic acid solution was chosen. Eluted americium has been, subsequently, determined by alpha spectrometry. Alpha samples were prepared using constant current electrodeposition technique from oxalate-sulfate electrolyte. The system characterization consisted of several experiments. At first, the dependence of americium weight distribution ratios on pH (ranging between 1.5 and 5.5; adjusted with nitric acid solutions) for four different dilutions of evaporator concentrate was studied, as well as blank experiments where americium weight distribution ratios dependences on pH for every dilution curve were determined for sorption on polyacrylonitrile matrix itself. Next, kinetics of this process, capacity of the used solid phase extractant, and elution profile of americium stripped by oxalic acid and loaded from various solutions were determined. Also the extraction behavior of americium in presence of various anions (namely nitrates, sulfates, oxalates, citrates and chlorides) in scale which can occur in real samples was investigated. The parameters of the electrodeposition process were optimized in an independent series of experiments; the most effective parameters were applied for the alpha samples preparation. Effectiveness of the electrodeposition method was monitored by comparing with simultaneously used liquid scintillation counting (LSC) method. As a result of a kinetics study, it was found out that about 97 % of americium uptake has been reached after half an hour of phase contact. The study of americium elution from TODGA-PAN resin filled column of bed volume equal to 0.24 mL, after its loading from the boric acid containing evaporator concentrate, revealed that almost all of the approximately 6 kBq of Am-241 loaded (97.43 ± 0.97 % or 98.26 ± 1.77 %, depending on the detection method used) could be eluted by about 1.7 mL of 0.25M oxalic acid solution.
Speaker: Mr Pavel Bartl (CTU in Prague)
• 32
An elemental portrait of the Portuguese wheat collection (in 2013) by instrumental neutron activation analysis
More than just being one of the "big three" cereal crops (with maize and rice), wheat is the staple food of humankind, with a history that is closely intertwined with humanity's own. Even if up to 100,000 plant species have been used -- on a regular or occasional basis -- since prehistoric times to meet the various needs (food, clothing, shelter, health) of an ever growing human population, wheat and its wild ancestors most likely were at the locus of an amazing evolutionary step that turned hunting and foraging/gathering individuals into settlers and, eventually, farmers. Domestication of diploid wild einkorn and tetraploid wild emmer is arguably thought to have begun some 10,000 years ago, although incipient cultivation of autochthonous landraces may have started well before that, in the early Holocene. The origins of such an agricultural beginning can be traced back to the vast and geographically diverse expanses of the Fertile Crescent in southwest Asia and the Middle East, while agriculture itself is, of course, the prominent feature of the so-called Neolithic Revolution, especially in what concerns cereal domestication (the above-mentioned einkorn and emmer wheats, and also wild barley). The status of wheat as the universal cereal of ancient agriculture has been kept through this day. Tonnage (though not acreage) of wheat grown worldwide may have been overtaken by both maize's and rice's shortly before the turn of last century, yet wheat remains unrivalled as to its latitudinal range of cultivation, crop area proper, caloric and nutritional relevance, and, last but not least, cultural significance at large. Current production is unevenly split between an overwhelming majority of hexaploid bread wheat (about 95 %), and a remaining share of (mostly) tetraploid durum wheat plus small amounts of hulled-grain wheat species (einkorn, emmer, spelt). Given such a background, no wonder that wheat germplasm was among the first to be stored in archival collections and seed banks, despite early general (technical) difficulties in preserving genetic resources as germplasm holdings. Besides, it is only fitting that wheat was the founding subject of one of the longest-running experiments in the history of science, the Broadbalk experiment at Rothamsted, UK (1843-present) -- 170 years and counting! Following the first morphological and taxonomic inventory of Portuguese wheats (1933), a collection of wheat cultivars has been maintained, replanted and documented by the National Institute of Agricultural and Veterinary Research, specifically by its former division known as the National Station for Plant Improvement (ENMP, Elvas). The ENMP collection has always been an invaluable asset in studies of agronomic and/or genetic development of wheat lines, as well as providing a reference frame for the nutritional evolution of Portuguese wheat crops. This work addresses the current status of major elemental nutrients and contaminants in a pool of 97 accessions of bread (52) and durum (45) wheat. All grain samples were irradiated at the Portuguese Research Reactor (RPI; CTN-IST, Sacavém) for 5 h, at a thermal-neutron flux density of 2.25E12 neutron per square cm and s, together with comparator disks of Al-0.1%Au. Gamma spectra were acquired with a liquid nitrogen-cooled, high-purity Ge detector. Elemental concentrations were determined through k0-standardized, instrumental neutron activation analysis (k0-INAA), and quality control was carried out by concurrent analysis of NIST-SRM 1567a, NIST-SRM 1568a and INCT-OBTL-5. In the discussion, focus will be given to essential nutrients like Fe, Mg, Se and Zn, and also to historical trace contaminants like As, as compared to current ionomic traits in modern European wheats. Special attention is paid to the (low) levels of Se, for which wheat acts as an important source in human diets, with a view to curbing its deficiency in Portuguese cultivars through agronomic biofortification.
Speaker: Ms Catarina Galinha (CERENA-IST, University of Lisbon)
• 33
Analysis of Hg and Pb by ICP-MS for the study of phytoremediation of Pb and Hg by Scirpus mucronatus
Phytoremediation is a procedure that uses plants to remove contaminants from the environment and it is a better option of recovery technique because of its cost-effectiveness and environmentally friendly especially for hyperaccumulator plants. Since heavy metals such as lead (Pb) and mercury (Hg) have limited bioavailability in the soil, methods to facilitate their transport to the shoots and roots of plant are required for efficient phytoremediation. The objective of this study was to investigate the effects of adding different heavy metal-tolerant bacterial inoculums (Brevundimonas diminuta SF-S1-5 and Alcaligenes faecalis SF-S1-60) on Pb and Hg accumulation in the shoots and roots of Scirpus mucronatus. The experiment was done in a greenhouse by planting acclimatized S. mucronatus in crates (52 cm length x 30 cm width x 25 cm height) with 30 kg sand and spiked with 100 ppm Pb and 1 ppm Hg, separately. The bacterial inoculums were added into the soil and the plants were watered using tap water to ensure the growth. The plants and sand samples were collected on day 1, 7, 14, 28 and 42, and the heavy metals in plant samples were extracted by using wet digestion method. The total concentration of Pb and Hg in samples was analyzed using Inductively Coupled Plasma-Mass Spectrometry(ICP-MS) and Atomic Absorption Spectrometer (AAS), respectively, and the phytoextraction ability was assessed in terms of its metal transfer factors; bioaccumulation factor (BAC), bioconcentration factor (BCF) and translocation factor (TF). Experimental results showed that after 42 days of treatment, the highest accumulation of Pb in shoot (265.8 ± 47.3 mg/kg-1 dryweight) was found in control plant (no addition of bacteria), while in root (697.2 ± 8.5 mg/kg-1dryweight) was found in plant inoculated with A. faecalis SF-S1-60. On the other hand, the highest accumulation of Hg (2.21 ± 0.08 and 5.71 ± 0.31 mg/kg-1 dryweight in plant shoot and root, respectively) were obtained in plant inoculated with A. faecalis SF-S1-60. In addition, plant inoculated with A. faecalis SF-60 showed the highest BAC and BCF values, and the lowest TF value compared to plant inoculated with B. diminuta SF-S1-5 and the control plant. This suggests that A. faecalis SF-60 can be utilized as an enhancer for accumulation of Pb and Hg in soil by S. mucronatus.
Speaker: Prof. Ainon Hamzah (Universiti Kebangsaan Malaysia)
• 34
Analysis of Lithium and Boron of Production and Real Samples using Cold Neutron Depth Profiling Method
Neutron Depth Profiling (NDP) is a nondestructive near surface method that can analyze the component nuclide concentration versus depth distribution in a sample by detecting the charged particles emitted after the neutrons are absorbed. NDP technique has became an important method to measure depth profiles of light elements such as lithium and boron in lithium battery and semiconductor materials. The Korea Atomic Energy Research Institute NDP (KAERI-NDP) facility has been installed at the HANARO research reactor. For the first application of the KAERI-NDP system, boron implanted and lithium deposition samples were prepared for depth profiling of 6Li and 10B. Additionally, electrode film samples were prepared by disassembling the lithium ion battery used in the mobile phone. The production and real samples were installed at the target chamber of the KAERI-NDP system and irradiated for different times with cold neutrons at the CG1 guide of the HANARO. The charged particle spectra were measured by using ion implanted Si detector. Measured spectra were analyzed and depth profiles of 6Li and 10B were determined. For the production samples where 10B implanted into the Si wafer, peak depth, peak concentration and aerial density was matched with those of SIMS method within 2, 6, 9%, respectively. In the case of lithium deposition samples, there was a difference of 6Li concentration profile in the deep region for the thick sample. 6Li concentration of the cathode of lithium battery was 5 times higher than that of the anode sample.
Speaker: Dr Byung Gun PARK (KAERI)
• 35
Application of ICP-MS for the determination of 99Tc and 90Sr in primary coolant water. Optimalization of measurements and analysis of potential interferences.
Sr-90 and Tc-99 are produced by the fission of U-235. Information on Sr, Tc and other fission and activation product content in the primary coolant and at various locations in the purification system can be of considerable value in assessing fuel integrity and performance of purification system component. Using inductively coupled plasma mass spectrometry (ICP-MS) for long-lived radionuclides improves detection limit and accuracy. However, in accurate measurements by ICP-MS method, the contribution of isobaric interferences from atomic- and molecular ions created by plasma gas and/or solvent used should be defined and appropriate ways of their elimination should be introduced. Also, to obtain accurate results in trace and ultra-trace analysis of Tc-99 and Sr-90, optimatization of measurements is necessary. In this work, the influence of different parameters (eg. sample flow rate, nebulizer type) on the strontium and technetium measurements have been taken into account. Acknowledgments: Research task No. 8 „Study of processes occurring under regular operation of water circulation systems in nuclear power plants with suggested actions aimed at upgrade of nuclear safety" partly financed by the National Research and Development Centre in the framework of the strategic research project entitled „Technologies Supporting Development of Safe Nuclear Power Engineering”.
Speaker: Ms Iwona Bartosiewicz (Institute of Nuclear Chemistry and Technology)
• 36
Application of the two-step approach to investigaion of chemical shifts and other electronic properties determined by core region of heavy atoms
Modeling of electronic structure and properties of actinide compounds is of considerable importance for modern radiochemistry. However, reliable and accurate estimates are a great challenge for quantum chemistry of actinides due to strong relativistic and correlation effects in such compounds. A development of theoretical approaches to this problem will stimulate application of a number of experimental techniques of analytic chemistry such as the method of chemical shifts in X-ray emission spectroscopy (XES). We report application of the theoretical method of generalized relativistic effective core potential [1] followed by the method of one-center nonvariational restoration [2] of valence electron wave function in the vicinity of heavy atoms to calculation of different properties of compounds containing heavy elements including actinides. Basing on the developed atom-in-compound (AiC) concept we demonstrate a possibility to use XES to control a number of properties that are determined by the core region of valence wavefunction. We show its applicability to provide a unified tool for indirect and independent accuracy check of the evaluated AiC characteristics. This is of great importance to the cases where an experimental check is difficult or even impossible [3]. The work is supported by the SPbU Fundamental Science Research grant from Federal budget #0.38.652.2013 and RFBR grant 13-03-01234-a. L.S. is also grateful to the President of RF grant no 5877.2014.2 and to the Dmitry Zimin Dynasty'' Foundation. 1. N.S. Mosyagin, A.V. Zaitsevskii, and A.V. Titov, Rev. At. Mol. Phys. 1, 63 (2010). 2. A.V. Titov et al., Int. J. Quant. Chem., 104, 223 (2005). 3. L.V. Skripnikov, A.N. Petrov, A.V. Titov, J. Chem. Phys. 139, 221103 (2013).
Speaker: Mr Leonid Skripnikov (St. Petersburg State University, Petrodvoretz, Russia; Petersburg Nuclear Physics Institute, Gatchina, Russia)
• 37
Characterization of multicrystalline silicon for photovoltaics by methods of neutron activation analysis
The improvement of solar cells by achieving higher efficiencies and lower production costs is getting more important because of the worldwide increase of photovoltaics as a renewable energy source. In this framework, the aim of DFG-Project HA 5471/4-1 (Department of Nuclear Chemistry, Johannes Gutenberg-University, Mainz, “Fraunhofer Institute for Solar Energy Systems” (ISE), Freiburg) is to optimize the methods of manufacturing and analysis of solar silicon. One manufacturing method is the directional solidification of raw and partly purified silicon (called “feedstock”). Based on their lower segregation coefficients, the impurities accumulate in the liquid stage during the solidification. The so produced silicon has acceptable concentrations of impurities and is called “solar grade silicon” (SoG-Si). For the analyses by means of Instrumental Neutron Activation (INAA) and Prompt Gamma Activation (PGAA) samples from SoG silicon as well as from highly purified silicon after the final solidification step are irradiated at three different research reactors: TRIGA Mainz, BR 2 Mol and FRM II Munich. Of special interest are the dopants boron and phosphorus and the 3d transition metals, which decrease the efficiency of solar cells by recombination of charge carriers. Profiles of these element concentrations in the produced silicon ingot as well as analyses of the impurity concentration in feedstock material and melting pot samples can help to improve the manufacturing method [1]. First results of measurements have shown a specific element distribution in produced silicon, caused by processes of diffusion and segregation [2]. Most of the elements, especially cobalt and boron, follow the Scheil-Equation [3] for distribution during directional solidification. With INAA the elements cobalt, iron, copper, chromium, antimony and scandium could be detected in silicon with a very low detection limit; with PGAA it was possible to measure boron at the ppb-level. [1] J. Hampel, F.M. Boldt, H. Gerstenberg, G. Hampel, J. V. Kratz, S. Reber, N. Wieh, Fast determination of impurities in metallurgical grade silicon for photovoltaics by INAA, Applied Radiation and Isotopes, 2011 [2] D. Macdonald, A. Cuevas, Transition-metal profiles in a multicrystalline silicon ingot, Journal of Applied Physics, 2005 [3] E. Scheil, Zeitschrift für Metallkunde, 1942
Speaker: Ms Barbara Karches (Department of Nuclear Chemistry of Johannes Gutenberg-University of Mainz, TRIGA)
• 38
Determination of 3H, 36Cl, 22Na, 85Sr and 133Ba by means of precipitation method
Spent nuclear fuel from the nuclear power plants owned by TVO (Teollisuuden Voima Oy) and Fortum, is planned to be disposed at a repository at a depth of more than 400 meters in the bedrock of Olkiluoto (Eurajoki, Finland). The repository system includes multiple release barriers: the nuclear fuel, copper canister with a cast iron insert, bentonite buffer around the canister and backfilling of the tunnels. Furthermore, the surrounding rock is the last barrier if the man-made barriers fail during the passage of time. Safe disposal of spent nuclear fuel requires information about the radionuclide transport and retention properties within the porous and water-containing rock matrix along the water conducting flow paths. The second in-situ experiment within ONKALO, the underground rock characterization facility in Olkiluoto, as part of the project “rock matrix REtention PROperties” (REPRO) was performed during 2013 using 3H, 36Cl, 22Na, 85Sr and 133Ba as tracer nuclides. The aim is to study the diffusion and sorption properties of nuclear compounds in the rock matrix under real in-situ conditions. A straightforward way to investigate properties of rock matrix under in-situ conditions is to carry out a water phase matrix diffusion experiment (WPDE2) in a two-meter artificial flow channel along the perimeter of the drillhole. The volume and aperture of the flow channel are minimized by an impermeable cylindrical flow guide inside the packer system. The inlet and outlet positions of water are located at the opposite ends of the packed-off section. WPDE2 tracer test is performed using a slow flow rate that is generated using a piston pump. The experiment is executed using synthetic groundwater to carry the tracer solution. This work presents the determination of radionuclides activities from the WPDE2 experiment giving the breakthrough curves of the radionuclides as a result. Rapid and precise determination of 3H, 36Cl, 22Na, 85Sr and 133Ba is of vital importance in the project. The activity of 22Na, 85Sr and 133Ba can be measured using gamma detector. Due to their electron emissions 22Na, 85Sr and 133Ba disturb the LSC measurement of 36Cl and 3H. So it is essential to seek a simple, convenient way to separate these radionuclides before spectrometric analyses. From the initial water sample 22Na, 85Sr and 133Ba are measured by gamma spectrometry first. Then NaCl carrier is added in solution. AgCl precipitation is produced and Ag(NH3)2Cl solution is measured with liquid scintillation analyzer to obtain the 36Cl activity. Sr(NO3)2 and Ba(NO3)2 carriers are added to the supernate and 85Sr and 133Ba are precipitated as carbonates; SrCO3 and BaCO3. This supernate contains 3H and 22Na and remains of 85Sr and 133Ba. Gamma emitting nuclides are measured first and then 3H with liquid scintillation analyzer. 22Na, 85Sr and 133Ba disturb the counting of LSC measurement. Thus using the quench curves determined for each of gamma emitting nuclides in 3H window of LSC, the amount of counts from the disturbing nuclides in 3H window can be calculated and reduced from the actual 3H counts. Then the “clean” 3H activities are determined by using the 3H quench curve. The separation procedure is optimized. The recovery of 36Cl is about 100% as well as the recovery of 85Sr while the recovery of 133Ba is slightly less, being about 85%. The detection limit for 3H in this solution is 1Bq/g. The precipitation procedure is easy and fast to separate 36Cl from the solution. 85Sr and 133Ba can be removed from the solution by carbonate precipitation in a way that 3H is measurable.
Speaker: Dr Lijuan Qian (Lanzhou University)
• 39
Determination of distribution coefficients of 134-Cs from Baltic Sea water using Cs-selective sorbents.
Radiocaesium is one of the most important radionuclides introduced into natural environment by human activity. In spite of its small concentration 137Cs and 134Cs may cause serious hazard in case of spread of fission products in the air or contamination water reservoirs. This risk is a result of high radioactivity and long decay time of mentioned radioisotopes. Decontamination of fresh or salty water needs special handling as a result of specific properties of caesium ions. Unlike to transition metals, caesium does not create insoluble precipitates and is weakly sorbed onto conventional cationic ion exchangers. Highly selective sorbents are used for that purposes. The most frequently used sorbents are titanates and silicotitanes, transition metal(II) hexacyanoferrates(II) and heteropolyacid salts. The minor role plays zeolites and natural organic sorbents. According to the Polish energy policy for the next two decades commissioning of two nuclear power plants is expected. In this poster a results of the determination of distribution coefficients of 134Cs from Baltic Sea water using commercially available and synthesised in a laboratory scale Cs-selective sorbents are presented. Comparison of these values may be important not only as an analytical purposes of radionuclide preconcentration, but also simulates decontamination of large volume salty water as a potential result of radioactive leakage. The research has been executed as a part of research task No. 8 „Study of processes occurring under regular operation of water circulation systems in nuclear power plants with suggested actions aimed at upgrade of nuclear safety" financed by the National Research and Development Centre in the framework of the strategic research project entitled „Technologies Supporting Development of Safe Nuclear Power Engineering”.
Speaker: Dr Krzysztof Borowik (Institute of Nuclear Chemistry and Technology)
• 40
Determination of Strontium Radionuclide Using Flow-Injection Analysis with ICP-MS Detection
Flow analysis is considered an efficient and universal technique of analytical science. Its wide range of advantages as compared to other known techniques is the argument for its increasing use. Thus, there may be distinguished a simple apparatus construction, which provides low sample use, together with an opportunity to implement many measurement concepts which are not always possible to achieve with common laboratory methods. Generally, this is understood as a variety of system constructions which are adapted to the analysts’ ideas and can assure that a sample in the flow is processed chemically i.e. by derivatization, even by multistage reactions, and also physically, for example by sample preconcentration. Another facility of the flow analysis is its automation ability, which means a full control over the fluid flow, its volumes, flow rates and timing. The main objective of the study is to develop and apply flow systems based on MSFIA - LOV (Multi-syringe flow injection analysis—Lab-on-Valve) to radioanalysis of strontium-90 in reactor coolant samples. The initial stage of research is to optimize the method of mechanized processing of samples. What is worth to remark, is that the construction of the system has been miniaturized enough to allow all the processes of sample preparation to take place in a several centimeters big reaction valve (LOV). The analytical procedure included a couple of stages—firstly, the column in the LOV was loaded with Sr-resinTM and conditioned. In the further stages, a sample was injected and its proceeding—the separation and concentration—took place in the LOV. The proposed analytical procedure included also the elimination of interferences from the elements disturbing detection (with similar affinity to Sr-resin i.e. Ba and isobaric interferences of 90Sr) as well as from the elements present in the coolant (boric acid). The optimization of the process included: selection of the solution and its volume to elute the retained strontium on a column with Sr-resin, the selection and optimization of the solution volume for the elution of interfering elements. The results of optimization were checked by using inductively coupled plasma mass spectrometry (ICP MS). The wide scale of implementation of this technique to monitoring and determination of radionuclides is a promising idea esspecialy for continuous monitoring of radionuclides in the reactor coolant.
Speaker: Ms Kamila Kołacińska (Institute of nuclear chemistry and technology)
• 41
Determination of U,Pu, Am /Cm Isotopes in Ash Resulted from the Incineration of NPP Cernavoda Low Level Waste
For the waste management characterization of radionuclides inventory is required. This work presents the method and the results for determination of U, Pu and Am/Cm isotopes in the ash resulted from the incineration of NPP Cernavoda, (Romania) low level activity waste, in order to have accurate information regarding the alpha emitting radionuclide content and a proper classification (LLW, ILW)of the waste. The sample is traced with U-232, Pu-242 and Am-243, then is decomposed in an open microwave digestion system by a mixture of a strong acids and peroxide. Hydrofluoric acid is used for destruction of silicates. Hydrofluoric acid is eliminated by addition of nitric acid several times. The residue is dissolved in nitric acid and aluminum nitrate solution. Uranium, Plutonium and Americium/Cm isotopes are separated from each other and from other radionuclides and matrix constituents by extraction chromatography . Two columns with UTEVA and TRUE Eichrome resine were used for separation .The sample solution is passed first through UTEVA resin that retains U isotopes, then loading and rinsing effluents are passed through TRU resin that retains Pu and Am/Cm isotopes. A redox adjustment of Pu was done before passing through UTEVA column using Fe(II) and NH2OH . HCl , and also into the TRU column using NaNO2. Ascorbic acid was used to reduce Fe(III) to Fe (II) in order to prevent the uptake of Fe (III). Uranium was eluted from UTEVA with diluted hydrocloric acid, americium is eluted from TRU with hydrocloric acid and plutonium is eluted from TRU with amonium bioxalat. The sample preparation for alpha spectrometry was done by cerium carrier co-precipitation. Alpha spectrometry of measurements were performed by Ortec Alpha Spectrometer System. average tracer recovery was about 50,6% for Uranium, 43,7% for Plutonium and 54,1% for Americium
Speaker: Mrs Adina Sandru (MATE-FIN srl)
• 42
Determination of Uranium Isotopes Composition Using LSC
Fast, simple and effective method for determination of enrichment/depletion of uranium samples that can be used not only in the laboratory but also for unknown samples at inspections outdoors, it is for longer time in insistent demand of specialists. The technique of liquid scintillation counting (LSC) in the mobile mode represented by Triathler LSC Counter (Hidex Oy) could be a valuable tool for this type of measurement. Application (usage) of this equipment allows several advantages: determination of enrichment/depletion under off-road conditions, combination of alpha, beta and Cherenkov counting (gives a complete picture required), milligram or even sub-milligram amounts of the sample (comparing e.g. to gamma-ray spectrometry), and easy preparation of the sample by mixing of U-salt with scintillation cocktail (comparing to e.g. alfa-spectrometry). The method can be used as the final step of suitable separation/concentration method. The method was also adjusted as a task for students in “Practical exercises in radiochemistry techniques” in the educational programme “BSc in Nuclear Chemical Engineering”.
Speaker: Dr Kateřina Čubová (CTU FNSPE, katedra jaderné chemie)
• 43
Development and application of method for determination of 89,90Sr in environmental samples by the use of NaOH for separation of strontium from calcium
The method allows cheap, safe and reliable determination of 89Sr and 90Sr in major environmental materials in sizeable quantities – water (500 L), soil (1000 g), milk (20 L), grass (1000 g), bone (1000 g), etc., routinely or in emergency situations (nuclear power plant accidents, “dirty” bombs, nuclear weapons detonation, etc.). Radiostrontium is leached by aqua regia from the ashes of the solid samples (burned at 5500C) or it is preconcentrated from the liquid samples by carbonate precipitation. The separation of strontium from the large quantities of calcium is atained by the use of NaOH – under heating or at room temperatures. Due to difference of solubility of strontium and calcium hydroxides in diluted alkaline solution (0.2-0.3M NaOH) calcium hydroxide can be precipitated while strontium hydroxide remains in the solution. When both 89Sr and 90Sr should be reported radiostrontium is separated from the isotopes of barium/radium/lead by precipitation of the latter as chlorides in hydrochloric acid. Otherwise when only 90Sr is expected to be present in the samples then separation (after ingrowth) of its daughter nuclide 90Y (from 90Sr and isotopes of barium/radium/lead) is carried out in sulfate and ammonium hydroxide media. Measurements are performed by liquid-scintillation spectrometer in Cherenkov mode (without scintillation cocktail) of purified 89,90Sr or purified 90Y. Chemical yields of strontium and yttrium is measured respectively by gamma-spectrometry (of 85Sr-tracer) and by titration (of stable yttrium carrier). The critical steps in the method were examined which resulted in reproducible chemical yields in the range 75 – 95%. The method has been used routinely at 2 laboratories in Bulgaria for analyses of more than 1000 samples in the last 7 years. The analytical quality was checked by analyzing reference materials with different matrices and regular participations in international intercomparisons. References: 1. Popov L, Hou X, Nielsen SP, Yu Y, Djingova R, Kuleff I (2006) J Radioanal Nucl Chem 269:161-173. 2. Popov L, Mihailova G, Hristova I, Dimitrova P, Tzibranski R, Avramov V, Naidenov I, Stoenelova B (2009) J Radioanal Nucl Chem 279:49-64. 3. Chen Q, Hou X, Yu Y, Dahlgaard H, Nielsen SP (2002), Anal Chim Acta 466:109-116. 4. Patti F, Hernandez A (1971), Anal Chim Acta 55:325-. 5. Chang TM, Chen SC, King JY, Wang SJ (1996) J Radioanal Nucl Chem 204:339-347.
Speaker: Dr Lyubomir POPOV (KOZLODUY NPP, Bulgaria)
• 44
Development and validation of robust analytical method for determination of Cr-51 in blood samples by LSC
Cr-51 is a radioactive isotope of chromium having a half-life of 27.7. The decay scheme indicates that 91% of the time, Cr-51 decays by electron capture directly to the ground state of the V-51 and emitting no gamma rays at all. Only 9% of the time the Cr-51 decays directly to the excited state of the daughter (V-51m), which then further decays by isomeric transition to the ground state, emitting a 320 keV gamma ray during the process. At the present, Cr-51 is used in many application fields, in particular, in medicine, where, thanks to its chemical properties, Cr-51 has found to be an excellent tool for the labeling of red blood cells in order to measure of mass or volume, survival time, and sequestration studies, for the diagnosis of gastrointestinal bleeding, and to label platelets to study their survival [1]. Nowadays, for the determination of C-51 activity in blood samples, usually, the conventional -spectrometry is applied [2]. In spite the fact that the method utilise almost no (or minimum) sample preparation steps, the careful attention for the calibration geometry should be paid. For instance, the calibration should be performed with the homogenised calibration standard (that is by blood samples is not always easy). On the other hand, the limit of detection, achieved by -spectrometry (depending on the type of detectors) are normally in the range of 10 Bq/g and relatively long counting times are required. However for some clinical studies, where the incorporated doses are sometimes restricted, a method with better detection capability would be absolutely preferable. Because of the electron capture decays the Cr-51 could be also detected using the Liquid Scintillation Counting [3]. Due to its simplicity, sensitivity and relatively simple sample preparation, this method was proved to be a suitable alternative for -spectrometry in order to determine the Cr-51 in blood samples. To prove this in the present study we developed a robust analytical method for measurement of Cr-51 in blood samples in routine mode by means of LSC. The method was validated with the synthetically prepared blood samples from different subjects. Prior to the measurements the samples were microwave digested in order to eliminate the matrix influence. The figures of merits, such as sensitivity, limits of detection and quantifications, precision and accuracy were studied and confirmed the capability of the method to determine the Cr-51 in blood samples in the range of 0,5 Bq per g of sample. All the results will be presented and discussed in details in the frame of current poster presentation. 1. Vandermeulen, E, et al. (2010). "Determination of optimal sampling times for a two blood sample clearance method using Cr-51-EDTA in cats ". Journal of Feline Medicina and Surgery 12: 577 2. Moreira D, et al. (2009). Determination of Cr-51 and Am-241 X-ray and gamma-ray emission probabilities per decay. Applied Radiation and Isotopes 68: 596. 3. Sheppard, G (1971), The Simultaneous measurements of Cr-51 and C-14 by Liquid Scintillation Counting International Journal of Applied Radiation and Isotopes, 22: 125
Speaker: Dr Myroslav Zoriy (Reserch Center Jülich)
• 45
Development of an in-situ radiotracer method to measure the adsorption phenomena of different alpha-emitters
The so called in-situ radiotracer methods are widely used for the determination of charge- and mass transport on the liquid-solid interfaces. With these methods different phenomena can be investigated, such as adsorption, corrosion, contamination or decontamination. Each technique is based on the thin layer principle of Aniansson, which claims, that the adsorbed amount of a radioactive isotope with soft radiation can be measured with low background noise in case of proper cell arrangement. In the past decades several methods were developed to measure the adsorption phenomena of different beta and soft gamma emitting isotopes in-situ (36Cl, 35S, 32P, 51Cr, 110mAg, etc.), but none for the alpha emitters. The alpha radiation measurement technique is extensive, several measurement methods have been developed to measure both intensity and spectroscopic parameters. However, the existing methods are not capable to measure under in-situ conditions, most of them are presume vacuum technique, in which case a continuous contact with the solution is not possible. To determine the adsorption of alpha emitters under in-situ conditions on compact surfaces development of a new technique is necessary, which is the aim of this work. The main steps of the research and development project are: • Selection of the proper detection technique • Design a cell construction, which fits the Aniansson principle • Preparation of a high activity pure alpha source • Calibration of the cell • Determine the main equations • Measure the adsorption phenomena of different alpha emitting isotopes This research was supported by the European Union and the State of Hungary, co-financed by the European Social Fund in the framework of TÁMOP 4.2.4. A/2-11-1-2012-0001 ‘National Excellence Program’.
Speaker: Mr Dávid Horváth (University of Pannonia, Institute of Radiochemistry and Radioecology)
• 46
Elemental determinations in biological and environmental sample using PGNAA facility at Dalat Nuclear Research Institute
In this paper we present the results of determination of element concentrations in biological, environmental samples by using PGNAA facility which was installed at channel No. 4 of Dalat research reactor. The biological standard samples, Bovine Liver NBS 1577a and Rye Grass BCR 281 and environmental standard samples, Coal Fly Ash NBS 1633a were analyzed to verify the analytical ability of the facility. After that, the concentrations of C, N, S, K, Cl in biological samples and concentration of Al, K, Ti, Mn, Fe, Ca, Gd, Sm, Cd and Si in environmental samples were determined. The detection limits of the above elements were also investigated.
Speakers: Mr Canh Hai Nguyen (Nuclear research institute), Prof. Huu Tan Vuong (Viet Nam Agency for Radiation and Nuclear Safety), Prof. Nhi Dien Nguyen (Nuclear Research Institute)
• 47
Fast procedure for self-absorption correction for low γ energy radionuclide Pb-210 determination in solid environmental samples
Low-energy X and γ radiations (for example of 210Pb: E γ = 46.5 keV) are effectively self-absorbed even in thin environmental samples, including air filters with captured dust or contaminated soil, as well as in bottom sediment matrixes with limited quantities of the samples. In this paper, a simple method for the direct analysis of 210Pb (T 1/2 = 22.3 years) by gamma-ray spectrometry in environmental samples with self-absorption correction is described. The method is based on the comparison of two γ peak activities coming from other natural radionuclides, usually present in environmental samples. The analysis the dependence of the self-absorption correction factor for the 210Pb activity on the activity ratios of 911 and 209 keV peaks and 609 and 295 keV peaks coming from nuclides of 238U or 232Th rows, present in typical environmental samples was done. Instrumental gamma spectrometry with HPGe detectors is usually applied for environmental radioactivity monitoring. The preferred method for the correcting of this effect is to use spiked or natural matrix reference materials. Commercially available radioactive standards allow us to establish the dependence of the detection efficiency versus the energy of c-photons in the wide energy range from 40 to 2,000 keV, for the fixed geometry (for example: cylindrical or Marinelli beaker and known chemical composition of the sample. However, several very important primordial and anthropogenic radionuclides occurring in the environmental samples emit low-energy photons in the range up to 200 keV, particularly: 210Pb—46.5 keV, 241Am—59 keV, 234Th (238U)—63.3 and 92.6 keV, 228Th—84.8 keV,235U—140, 163 and 186 keV and 226Ra—186 keV. For these radionuclides one should take into account the occurrence of the self-absorption of soft c radiation in the measured samples, which strongly depends on the density, resultant atomic number—Z and geometry of the samples. Therefore, instrumental gamma ray spectrometry may require additional corrections for self-absorption of gamma rays, as environmental samples often differ in densities and composition from each other, and the offered calibration standard reference materials may have slightly different chemical compositions. Generally, two basic approaches have been applied for solving the problem of self-attenuation in volume samples: experimental and mathematical— using Monte Carlo simulations. Finally, a few computer programs have been developed for calculating the corrected detection efficiency for samples with a normalized shape with a known chemical composition (e.g. LabSOCS). In all solid environmental samples together with the very important 210Pb radionuclide there are other natural radionuclides. Some of them emmit at least one of the pair of photons with different energies. Simultaneous determination of the ratios of their c-line activities can be a valuable method for searching for small chemical changes in the examined matrixes. We have proved this for at least following radionuclides: 228Ac emitting with sufficient efficiency photons with energies 209 and 911 keV, or a pair of 214Pb–214Bi with gamma-ray energies of 252 and 609 keV can be used for simultaneous self-absorption correction in the determination of the another soft-gamma emitter—210Pb.
Speaker: Dr Magdalena Długosz-Lisiecka (Technical University of Lodz, Faculty of Chemistry)
• 48
Implementation of calculation codes for corrections of systematic effects in measurement laboratories
A vast number of papers are reporting on the development of calculation codes for corrections of systematic effects in gamma spectrometry. Many comparison studies have also been performed where differences and similarities between many of those calculation codes are presented. However, most studies performed in this area are performed for the experienced user or program developers. Despite the high quality of those papers and the important information about the calculations codes, when selecting, implementing and using these codes at different laboratories regular users are often struggling with other issues. This study aimed at considering a user perspective for correction of common systematic effects within gamma spectrometry that measuring laboratories are facing in their daily work. A coincidence free calibration was established for a volume source at an endcap position by characterising the detector geometry using the calculation code VGSL (Virtual Gamma Spectrometry Laboratory). Furthermore, four different calculation codes (ANGLE, EFFTRAN, GESPECOR and VGSL) were compared by calculating corrections factors for true coincidence summing (TCS), fill degree in the sources and new source-detector geometries. Two of the calculation codes are simulation codes and two are semi-empirical codes. The detector model was optimized with VGSL and thereafter the same model was used in the other softwares. There are differences in how the correction factors are calculated in the calculation codes, by Monte Carlo simulation or efficiency transfer. Also the degree of details of the detector and source parameters that can be entered varies between the codes. Within the scope of the investigations in this study this has not shown any effects on the results. Furthermore, despite the fact that the detector model only was optimized with one of the calculation codes no clear differences could be observed as a result from this. The uncertainty of the TCS corrected activities were found to be in the same magnitude as the certified activities in the reference solution itself. When activities were corrected for different filling degrees in the sample sources the deviations from the certified reference solution were generally lower than 5%. Larger deviations were observed, around 10% or less, when activities were corrected for new source-detector geometries. Discrepancies between 5 and 10% are often considered to be acceptable for some applications, i.e. environmental or survey monitoring. This is an important knowledge for cases when it can be motivated to calculate corrections for other source-detector geometries. However, measurements should preferably be performed in source-detector geometries closely resembling the calibration geometry since those corrected activities are associated with lower uncertainties. The user should carefully select the proper calculation code that will cover the need of the measurements that will be performed, i.e. if TCS corrections are needed and what detectors and sources will be used. When implementing the calculation code at the measuring laboratory it is of greatest importance to validate the calculations and thereby identify within what boundaries the corrections are valid. It can be concluded that all the investigated calculation codes in this study are robust and will give reliable measurement results.
Speaker: Dr Sofia Jonsson (1) Swedish Defence Research Agency, FOI, division of CBRN Defence and Security, SE-901 82 Umeå, Sweden)
• 49
In-beam neutron activation analysis at FRM II, Garching
The thermal equivalent neutron flux at the prompt gamma activation analysis (PGAA) facility at the Forschungsneutronenquelle (FRM II) at Garching, Germany is 6x1010 cm–2 s–1 which is the highest beam flux reported. This beam intensity is already strong enough to activate samples for the purpose of neutron activation analysis (NAA), too. This option has been used together with PGAA simply performing decay counting after switching off the beam using the same spectrometer used for the in-beam measurement, and proved to be useful in the case of a handful of elements, like Na, Mn etc. The main advantage of in-beam activation is that the beam contains no epithermal or fast neutrons, thus realizing activation in its purest form. Many elements, like Al, Sb, or Ge could not be analyzed in this way, because they appear in the spectral background. Recently, a low-background counting chamber has been installed a few meters away from the PGAA instrument using a 30-% HPGe detector equipped with a mechanical cooler and covered with 10 cm of lead, boron and lithium-containing sheets against neutrons and tin to attenuate lead x-rays. The background conditions are much better for this spectrometer, at the same time the counting efficiency is also higher. This enables us to analyze a larger number of elements off-line. The first results will be presented at the conference.
Speaker: Dr Krzysztof Kleszcz (Technische Universität München, Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II))
• 50
Innovations at the MT-25 microtron aimed at applications in photon activation analysis
Microtron is a high frequency cyclic accelerator of electrons with fixed frequency and constant magnetic field. Electrons are accelerated in a cavity resonator by high frequency energy supplied by high pulse power of a magnetron, orbit within an accelerating chamber in circular trajectories with gradually increasing diameters, gaining gradually higher energy, and can be extracted from individual orbits to achieve required beam energy. The accelerated electron beam can be converted into high energy photon radiation - bremsstrahlung - on a target made usually of tungsten. Microtron can thus be used as an effective source of high energy photon radiation for use in photon activation analysis (PAA). With a suitable secondary converter, microtron can be used also as a neutron source suitable for neutron activation analysis. In 1981, microtron MT-22 built at the Czech Technical University in Prague in collaboration with JINR Dubna started operation. After ten years of operation, MT-22 was replaced by a new, chamberless microtron MT-25. In 2003, MT-25 was made over to the Nuclear Physics Institute, ASCR (NPI) and its modernization started aimed at upgrading microtron parameters such as the mean accelerated electron current, quality of the beam and irradiation fields, and attaining better long-run operation stability and reliability. MT-25 delivers highly monoenergetic electrons within the energy range 6 - 25 MeV with the maximum mean beam current 25 microA. Stable operation of MT-25 at a 20 microA mean electron current (at >20 MeV energy) started in 2006, and its utilization for PAA on a larger scale has been re-established. Several, mainly geochemical and cosmochemical studies have been carried out or are underway. Until recently, PAA analyses could be carried out only in the offline regime, i.e., in assay of elements providing by photoactivation radionuclides with sufficiently long half-lives. Currently, installation of an automated system for rapid sample transport between the beam position and detector in the short time, online irradiation regime is being completed which will provide substantial extension of the analytical range of IPAA. The system has been designed as a pneumatic tube system driven by three vacs and controlled by a commercially available modular programmable controller. The irradiation chamber has been designed as a rotation device with the axis of rotation perpendicular to the axis of the beam. The system enables special operations, such as multiple irradiation-counting cycles, counting sample either in a transport/irradiation vial or its manual removal from the vial before counting, etc. An important part of the system is a four-way switch (router) placed above a detector shielding. Operation of the microtron MT-25 has so far been controlled manually. For a routine operation, especially for repeated short-time irradiations, it is desirable to run microtron in a continuous stable regime with minimum fluctuations of the electron beam energy and current between irradiations of individual samples. Also for this purposes, a new fuzzy control system for the microtron MT 25 has been designed and optimized. The control system is based on a Mamdani-type fuzzy regulator using an operator description and a mathematical model of the microtron. The system allows controlling the energy and the current of accelerated electrons at required values. The fuzzy controller was tested with the aid of the mathematical model with satisfactory results and its optimization was performed with the help of a genetic algorithm. The optimization was performed in two phases, the first one aimed at maximizing speed of the control process and minimizing the control error, and the second one at minimizing the control overshoot. A real control system has currently being tested with encouraging results. The work has been supported by the projects 13-27885S and P108/12/G108 of the Czech Science Foundation.
Speaker: Jiří Mizera (Nuclear Physics Institute, Academy of Sciences of the Czech Republic)
• 51
Innovative technique for rapid measurement of post-accidental 89Sr in water: use of the Cerenkov Effect combined with color quenching
Many techniques have been developed in the interest of measuring radionuclides activity concentration in environment in case of a nuclear accident. Some so called “crisis” techniques are currently under development at the Institut de Radioprotection et de Sûreté Nucléaire in France in order to rapidly measure radioactive isotopes of interest and provide information to the authorities. Especially, strontium 89 and 90 can be radioactive isotopes of interest. They are both pure beta emitters. Because of their toxicity and the similarity of their physical and chemical behavior with calcium, these elements may be found through the food chain. Strontium 89 has a half-life of 50.5 days and can reach an activity concentration 10 to 170 times higher than strontium 90 in case of accidental reject. After the Fukushima accident, the necessity of quantifying rapidly strontium 89 and 90 appeared. It is therefore essential to measure their activity concentration in the environment [1]. The technique we are going to present concerns the determination of the activity concentration of strontium 89 and 90 in water, according to the 89Sr/90Sr ratio. It consists of two stages: the chemical separation by ionic chromatography and the measurement of the activity concentration of strontium 89 and 90 with a liquid scintillation counter. The automated separation is performed from the adaptation of an existing ionic chromatography, whose features are not to measure cations but to separate and isolate strontium. It is important to understand that right after the isolation of strontium, the decay product of 90 strontium (yttrium 90) will grow instantly. The measurement step is also singular because of the use of Cerenkov Effect on a quenched sample. The quenching is realized by applying a thin colored film on the sample vial. As beta particles energy of strontium 90 is low for Cerenkov Effect (540 keV), its counting efficiency is very low. The colored quench is therefore used to make disappear the number of counts on the spectrum caused by strontium 90. This way, yttrium 90 ingrowth and strontium 89 decay are exclusively measured (E90Sr < E89Sr < E90Y). Successive countings and modeling of the ingrowth/decay kinetics allow us to evaluate the activity concentration of strontium 89, and 90 depending on the 89Sr/90Sr ratio. The results we are going to present at Radchem 2014 concern the development of the chemical separation by ionic chromatography and measurement of strontium by Cerenkov Effect. Studied parameters such as the quenching parameter to use, the sample geometry and the influence of 89Sr/90Sr ratio will be discussed. Results on proficiency test samples and standard solutions will also be shown. At last, an estimation of the total analyzing time comprising the separation and measurement steps will be given. [1] Tovedal A, Nygren U, Ramebäck H. Methodology for determination of 89sr and 90sr in radiological emergency: i. scenario dependent evaluation of potentially interfering radionuclides. J Radioanal Nucl Chem 2009, 282(2), 455–459.
Speaker: Dr Kevin Galliez (IRSN)
• 52
Instrumental Neutron Activation Analysis for the Determination of Gold Nanoparticles in Mice Tissues
Gold nanoparticles (GNPs) have been utilized in high technology applications such as organic photovoltaics, sensory probes, therapeutic agents, drug delivery in biological and medical applications, electronic conductors and catalysis. GNPs for use as molecular imaging probes and their biodistribution in safety reason have been studied, widely and intensively. The objective of this study was to evaluate the capability of neutron activation analysis (NAA) method to determine GNPs in mice tissues and biological samples. 10 nm GNPs were instilled into a mouse and eleven tissue and biological samples such as blood, bone, brain, gonad, heart, intestine, kidney, liver, lung, spleen and stomach were prepared for NAA. The prepared sample was irradiated for 10 minutes with thermal neutrons using the Pneumatic Transfer System (PTS) at the HANARO research reactor in the Korea Atomic Energy Research Institute (KAERI). Acquisition of the gamma-ray spectrum was carried out using a high purity Ge detector coupled to DSPECPLUS. Intravenously administered GNPs were detected only in the liver and spleen samples. On the contrary, orally administered GNPs were detected in the stomach and intestine samples. High amount of Na in the samples hampered the detection of GNPs and minimum detection limit for GNPs in these samples was approximately 0.01 mg/kg.
Speaker: Mr JongHwa MOON (Korea Atomic Energy Research Institute)
• 53
Instrumental photon activation analysis with the MT-25 microtron
Instrumental photon activation analysis (IPAA) is a useful and complementary method to instrumental neutron activation analysis (INAA). IPAA allows determination of number of elements not determinable by INAA, and determination of many elements with a better sensitivity than INAA. Unlike INAA based mainly on the neutron capture reactions (n,gamma), PAA is based on photonuclear reactions, particularly photodisintegration reactions (gamma, n) and (gamma,p), and photoexcitation reactions (gamma,gamma’). These reactions take place only at photon energies exceeding a threshold. This can be utilized in optimizing beam energy at irradiation of a specific sample, when partial suppression of interfering nuclear reactions can be achieved by keeping the maximum photon energy below or only slightly above their threshold. Particularly in analysis of geological samples (minerals and rocks), this reduces substantially, compared to INAA, matrix effects hindering determination of trace elements. Higher penetration of high energy photons and lower activities produced allow also analysis of larger samples. An effective source of the high energy photon radiation for use in IPAA is the secondary radiation - bremsstrahlung - produced at deceleration of electrons accelerated in a high frequency cyclic accelerator - microtron. The MT-25 microtron built at the Czech Technical University in Prague in the late 1980s, after its takeover and modernization by the Nuclear Physics Institute ASCR in the years 2003-2005, has been utilized regularly for purposes of IPAA. Until recently, IPAA analyses could be carried out only in an offline regime, i.e., in assay of elements providing by photoactivation radionuclides with half-lives long enough for counting with a sufficient count yield even after decay time elapsed between switching off the microtron and manual delivery of sample to a detector. Currently, installation of an automated pneumatic system for rapid sample transport between the beam position and detector in an online regime is being completed which will, regarding numerous short-lived products of photonuclear reactions, provide substantial extension of the analytical range of IPAA. The contribution presents possibilities and recently realized examples of utilization of IPAA with the MT-25 microtron, namely a recently developed and optimized procedures for fast fluorine and nitrogen assay, and their application in analysis of various materials. The work has been supported by the projects 13-27885S and P108/12/G108 of the Czech Science Foundation.
Speaker: Mrs I. Krausová (Nuclear Physics Institute ASCR)
• 54
Investigation of hydrophilic materials as hypoxic phantoms
Cross-linked hydrophilic co-polymers are candidates for use as phantom materials because they can be modified to have similar elemental compositions to that of body soft tissues. Co-polymers contain both hydrophobic and hydrophilic monomers; the molar ratio of which allows the water-uptake ability to be controlled. By controlling the hydration level, it may be possible to imitate various types and different disease stages of tissues, as well as the extent of tissue hypoxia. A series of experiments was carried out for different types of cross-linked hydrophilic co-polymers; hydroxyethyl methacrylate/Vinyl pyrrolidone (HEMA-VP) and methyl methacrylate/Vinyl pyrrolidone (MMA-VP) were hydrated by biological fluids with or without the reducing agent AnaeroGen to obtain hypoxic condition or normoxic condition; respectively. The relative yield of 3γ-to-2γ annihilation photons was determined using the positron emitter, Na-22, with a lanthanum bromide:Cerium (LaBr3:Ce[5%]), scintillation detector. The peak-to-peak method was used to calculate the ratio of the full-energy photopeak area of the 511keV annihilation obtained in the sample and the aluminium reference material. The Na-22 source used has a positron yield of 90.4% and a gamma-ray energy at 1274keV of relative intensity 99.9%, emitted almost simultaneously. The energy resolution and the intrinsic photopeak efficiency figures for LaBr3:Ce were (3.37±0.08)% and (29.1±0.8)%, respectively for the 511keV annihilation energy. The relative yield of 3γ-to-2γ annihilation photons was calculated and discussed in different hydrophilic co-polymers.
Speaker: Dr M Alkhorayef (Centre for Nuclear and Radiation Physics, Department of Physics, University of Surrey, Guildford, Surrey, GU2 7XH, UK)
• 55
Natural radionuclide extraction from aqueous solutions by ionic liquids
Natural radionuclide extraction from aqueous solutions by ionic liquids Gabriele Wallner, Orhan Sap, and Regina Krachler Institut für Anorganische Chemie, Universität Wien, Währingerstr. 42, A-1090 Wien, Austria e-mail: gabriele.wallner@univie.ac.at Abstract Ionic liquids (ILs) are salts with a low melting point (below 100 °C) and they are composed of completely dissociated ions. ILs have many advantages and they are of growing interest in the field of green chemistry. Most of the commonly used ILs are composed of large organic cations and the basic compounds consist of e.g. imidazolium, pyridinium, pyrrolidinium, ammonium and phosphonium(1). Some of the unique properties of the most widely studied ILs include the large liquid temperature range, high thermal stability, electrical conductivity, and tunable physical properties. Especially the extraction of uranium by using ILs is of enduring interest in the literature as it may also be relevant to spent fuel reprocessing.(4,5) The presented work is part of a project dealing with purification processes for drinking water. The aim of our work was the extraction of Uranium, Radium and Polonium from aqueous solutions with an IL as well as its back extraction (Pb-210 has not been taken into account here as it is removed together with stable lead). Especially the conventional anion exchange step for uranium separation from water (or other sample matrices) is very time consuming (pre-concentration and column chromatography), while the liquid-liquid extraction into an IL also takes its time, but can be done by automated systems. Investigations in our laboratory a few years ago demonstrated that extraction of uranium from water is possible with [A336][TS]2,3, tricaprylmethylammonium thiosalicylate. The ILs under investigation now are [A336][MTBA], tricaprylmethylammonium 2-(methylthio)benzoate, as well as [Mal][A336], [Thiom.][A336], [Mal][Cyphos], [Thiom.][Cyphos], [A336][Ant], [PR4][Ant], [A336][DBA], [PR4][DBA]. Investigations were performed with an artificial uranyl nitrate solution of a known amount of uranium (e.g. a few µg U in 10 ml diluted nitric acid) and mixed with the respective ILs. After centrifugation the phases were separated and the aqueous phase was analysed by liquid scintillation counting (LSC) to ensure that the uranium was removed. Afterwards acids of different molarity or EDTA solutions were used for back extraction of uranium from the organic phase. For the investigation of the other nuclides, water samples with known amounts of Ra and Po were used (reference samples or mineral waters). For application in the field of drinking water purification we searched also for immobilisation of the ILs on a suitable backing material. Our goal is to find a new method to shorten and simplify the chemical procedure for the determination of radionuclides (especially uranium) in natural (water) samples as well as to look for a new purification method for drinking water supplies. [1] Violina A. Cocalia, Keith E. Gutowski, Robin D. Rogers, Coordination Chemistry Reviews, 250, 2006, 755- 764. [2] Daniel Kogelnig, Anja Stojanovic, Markus Galanski, Michael Groessl, Franz Jirsa, Regina Krachler, Bernhard K. Keppler, Tetrahedron Letters 49, 2008, 2782-2785. [3] Michaela Srncik, D. Kogelnig, A. Stojanovic, W. Körner, R. Krachler, G. Wallner, Applied Radiation and Isotopes 67, 2009, 2146-2149. [4] James E. Quinn, M.D. Ogden, K. Soldenhoff, Solvent Extraction and Ion Exchange 31, 2013, 538-549. [5] Dimitrios Tsaoulidis, V. Dore, P. Angeli, N.V. Plechkova, K.R. Seddon, Chemical Engineering Journal 227, 2013, 151-157.
Speaker: Prof. Gabriele Wallner (Institut für Anorganische Chemie, Universität Wien)
• 56
Neutron Activation Analysis of Children’s Hair from Altai Republic
The study focuses on the chemical composition of human hair as an indicator of the level of income of the chemical elements in the human body and its impact on growth and development of children and teenages in the local geochemical conditions. Neutron activation analysis (NAA) was used to analyze 186 samples of hair of children from four villages of Altai Republic. Data for 54 boys and 132 girls in the age of 7 to 17 were analyzed. Significantly higher content of sodium, aluminum and chlorine was observed in the hair of boys over girls. The following short-lived isotopes were determined: Na, Mg, Al, S, Cl, K, Ca, V, Mn, Cu and I. Concentrations of magnesium and calcium were significantly higher in the hair of girls. Iodine, copper, manganese and sulfur concentrations in the hair of boys and girls are close to each other, the differences between the sexes are not significant. Median concentrations of the studied elements in the hair of boys and girls were, respectively: Na – 75 и50; Mg – 49 и62; Al – 21 и13; S – 41150 и39850; Cl – 1020 и390; Ca – 608 и973; Mn –1,1 и0,82; Cu – 9; I – 0,2 mg/g. It was shown that the high content of calcium and magnesium is observed in the hair of children living in rural areas with high hardness and salinity of drinking water. Iodine concentrations in the hair of studied cohort of children is low, especially in puberty.
Speaker: Ms Zoya Goryainova (Joint Institute for Nuclear Research)
• 57
Nuclear analytical merthods for studying elemental composition of calciofied tissuers
Various nuclear activation techniques have been developed and applied to determine the elemental composition of calcified tissues (teeth and bones). Fluorine was determined by prompt gamma activation analysis through the 19F(p,a)16O reaction. Carbon was measured by activation analysis with He-3 ions, and the technique of Proton-Induced X-¬ray Emission (PIXE) was applied to simultaneously determine Ca, P, and trace elements in well-documented teeth. Dental hard tissues: enamel, dentine, cementum, and their junctions, as well as different parts of the same tissue, were examined separately. Furthermore, using a Proton Micro-probe, we measured the surface distribution of F and other elements on and around carious lesions on the enamel. The depth profiles of F, and other elements, were also measured right up to the amelo-dentin junction. A new technique has been developed for studying the depth profiles of F in teeth, non-destructively, to larger depths than hitherto known. It is further shown that using this technique depth profile of any element/isotope can be determined non-destructively as long as the reaction cross sections of the particular nuclear reaction are available. Some results on the microscopic spatial distributions of various elements in kidney stones, using the powerful technique of Laser-Ablation Inductively-Coupled Plasma Mass Spectrometry (La-ICP-MS) are also presented.
Speaker: Prof. Mohammad Anwar Chaudhri (Institute of Biopphysics, Center for Medical Physics and Technology, University of Erlangen-Nuernberg, Erlangen, Germanyrnberg, Germany)
• 58
On the development of a rapid method for the determination of Pb-210 in water samples based on TK100 Resin
The crown-ether based SR Resin is frequently used for the separation and determination of Pb-210 in aqueous samples via liquid scintillation (LSC) or gas proportional counting (GPC). The resin only shows significant Pb (and Sr) retention at moderate to high acid concentrations; it does thus not allow for direct loading of Pb from acidified or raw water samples, making the additional use of pre-concentration steps such as ion exchange or co-precipitation necessary. In order to simplify and quicken the Pb-210 determination an extraction chromatographic resin (TK100 Resin) allowing the direct load of Pb from water samples and its subsequent purification on the same resin has been developed and characterized. The TK100 Resin is based on the crown-ether also used in the SR Resin; accordingly its selectivity and robustness against interferences from common matrix elements, such as e.g. Ca and Mg, are similar to that of the SR Resin. However, by including HDEHP into its composition Pb can now be extracted at a much wider range of pH conditions, i.e. pH £8. Conditions allowing the removal of other beta emitters (e.g. Sr-90, Bi-210, Y-90) from the resin, and for the final elution of Pb from the resin, have been identified. Elution studies have been performed with the resin in column form as well as in disc form, the latter having the advantage of allowing higher flow rates. It could be shown that Pb uptake was very high even at elevated flow rates (e.g. 10 mL/min for columns and 30 mL/min for discs). The new rapid method was tested on spiked tap water samples. Samples of up to 5 L were directly loaded onto the resin in column or filter geometry at elevated flow rates; Pb was retained on the resin, purified and finally eluted with high chemical yield and purity. The direct measurement of Pb-210 loaded discs by liquid scintillation counting is being evaluated in order to further speed up the method.
Speaker: Dr Steffen Happel (TrisKem International)
• 59
Performance Evaluation (PE) Samples as Part of Laboratory Quality Control.
Role of PE samples in the Laboratory Quality control is briefly discussed. Eckert & Ziegler Analytics (EZA) capabilities are outlined. New Fission products Mixture (FM) is introduced. This mixture of radionuclides represents real fission products resulted from the irradiation of natural or enriched Uranium with thermal neutrons. Analysis of this mixture is real challenge and it can be very valuable tool for training and proficiency testing. Fission mixture has several advantages over existing EZA activation/fission mixture: - FM contains same array of radionuclides as post-accident samples, - Over 20 isotopes with reasonable half-lives can be certified, - Liquid FM samples can test laboratory ability to handle samples properly prior to analysis. Improper sample container, preservation, storage conditions etc. can significantly alter analytical results. - Gamma spectrometry of this mixture requires extensive knowledge of the methodology and particularly the correct application of software used for gamma analysis. Analytical laboratory will need to: - analyze complex isotope mixture, properly identify isotopes using key gamma lines and correctly apply interferences, - properly apply coincidence summing corrections, - decay results for the reference date, - properly recognize and calculate parent/progeny pairs like Zr-95/Nb-95, I-132/Te-132, Mo-99/Tc-99 etc., - identify additional radionuclides. - FM can be used to identify non gamma emitting radionuclides like Sr-89, Sr-90, Pu-239 etc. based on fission yields, nuclear reactions and irradiation conditions. Fission mixture samples can be delivered as liquid samples and other configurations like filters and cartridges.
Speaker: Dr Evgeny Taskaev (Eckert &amp; Ziegler Analytics, Inc.)
• 60
Quality control for routine k0-NAA applications at Nuclear Physics Institute, Řež
Implementation of the k0-NAA in Řež aimed at the development of routine panoramic trace-element analysis method for samples with various matrices and of different origin. To meet the customers’ expectations, procedures and practices have been established to ensure the high quality of the results produced, such as, calibration of the equipment used (scales, pipettes, detectors), in-situ determination of neutron flux parameters in irradiation channels of the multipurpose research LVR-15 reactor, use of replicates (if possible), blank analyses, use of certified reference materials, namely NIST SRMs 1547, 1633B, 2711, and/or others in case of availability, preferably with a good matrix-match to the samples to be analyzed. Using results of the SRMSs, control charts are maintained to monitor the long-term stability and quality of the assays. For most elements, agreement is obtained with the certified values within uncertainty margins. A procedure has also been designed to use noncertified values for quality control in the same way as the certified values. In a few cases, however, results deviating from the certified or noncertified values are consistently being found, although the differences are not of a systematic nature. Such cases are topics of our future studies. To test and improve the quality control measures, our lab also successfully participated in several inter-laboratory comparison rounds organized and sponsored by the IAEA using test samples of plant and soil origin provided by the Wageningen Evaluating Programs for Analytical Laboratories (WEPAL).
Speaker: Dr Marie Kubešová (Nuclear Physics Institute, ASCR)
• 61
Rapid Analysis of Uranium Concentrations in Powder Rock Samples by a Delayed Neutron Counting
A delayed neutron counting system installed at the HANARO research reactor in the Korea Atomic Energy Research Institute was applied to the analysis of elemental uranium concentrations in the rock samples collected at the Samcheok area, northeastern Yeongnam massif, South Korea. For the accurate determination of uranium, the correction of thorium interference was carried out. The resultant values are consistent with the values determined by the ICP-MS. The DNC method was proven to be a very rapid and excellent method for the quantification of the uranium concentration in the geological samples. Keywords: Delayed neutron counting, uranium concentration, thorium concentration, rock samples
Speaker: Dr Gwang-Min SUN (KAERI)
• 62
Rapid separation and determination of 107Pd and 79Se from intermediate level radioactive waste from NPP A1
Palladium 107Pd and Selenium 79Se are amongst nineteen limited radionuclides monitored in wastes disposed at national repositories in Slovak Republic. Both of these radionuclides are pure beta emitters with energies Ebeta,max 150.7 keV; 33 keV respectively. Such low energies of beta spectra make them very difficult to measure. The best possible method of determination is liquid scintillation counting. Even LSC methods are to be much more sophisticated than simple photomultiplier tube measurements; triple-to-double coincidence ratio liquid scintillation counting is one of the best methods to determine these difficult to measure radionuclides. Radiochemical separations of these radionuclides are not even in these days exactly described. Procedures are either very complex or other parts of procedures are dealing only with selenium and palladium as a toxic element and heavy metal therefore the emphasis is on determining with instrumental methods: ICP MS, ICP AES and ICP OES. These methods cannot be used in case of intermediate level RAW. Intermediate level, historic RAW from NPP A1 are presently disposed. Since at A1 NPP occurred INES 4 accident in year 1977, cladding of many fuel assemblies was violated, even one fuel assembly was melted down, whole spent fuel storage, reactor vessel and other storages for fuel assemblies were severely contaminated with fission, activated and transuranic elements with specific activities up to 1011 Bq/kg. This paper is describing development of selenium 79 separation in steps consisting precipitation of selenium into its metallic form and achievement of desired radionuclide purity with ion chromatography. Determination of palladium is studied in few simple precipitation steps with DMG and co-precipitation of other pollutants. Both limited radionuclides are determined with liquid scintillation counting with TDCR.
Speaker: Mr Boris Andris (VUJE a.s.)
• 63
Selenium in bread and durum wheats grown under a soil-supplementation regime in actual field conditions, determined by cyclic and radiochemical neutron activation analysis
Selenium (Se) is an essential trace nutrient whose importance in human health is simply not up to par with its relative abundance in the Earth's upper continental crust: it is one of the least-common elements, with an average concentration that makes it rarer than, for instance, gold. Though ubiquitous, Se also features an uneven distribution in agricultural soils, that act as its port of entry into the nutritional path through uptake and accumulation by edible plants, even if such an element is not required for their own growth. Since the Se transfer up the soil-plant-(animal)-human food chain is generally efficient, that soil-Se imbalance easily translates into substantial variation in food-Se content and, ultimately, into significant divergence in human-Se intake. The ever-increasing attention paid to the role of selenium and selenoproteins in human health stems primarily from an ever-growing body of evidence about not only their actual (general) importance for defending against oxidative stress/damage and thyroid malfunction -- that is against immune failure at large -- but also about their potential (beneficial) effect in a plethora of life-threatening issues (cardiovascular disease, critical illness and, especially, cancer) or, at least, life-deteriorating (cognitive, metabolic and reproductive) conditions. Some evidence may be inconclusive or even inconsistent, yet the relevance of selenoproteins to health seems unquestionable. Such an importance has since been recognised by both global organizations and national authorities, leading to a range of dietary recommendations for Se intake that currently averages 60 and 53 microg per day for adult men and women, respectively. An extensive investigation of Se levels in cereals and their cultivation soils has been carried out across the main production areas of mainland Portugal, with a view to an eventual Se supplementation of major cultivars. Breads and cereal derivatives (breakfast blends, pastas, etc) make up a considerable share of Portuguese diets, so an increase in the bioavailability of Se through supplementation of crops may contribute to an upgrade in the Se status of the whole population. Cereals are far from being the main sources of Se on a content basis, but they are likely the major contributors to intake on a daily basis. The present paper focuses on the ability of bread and durum wheat -- Triticum aestivum L. and Triticum durum Desf., respectively -- to accumulate Se after supplementation via a soil-addition procedure. Four of the most representative wheat cultivars in the country -- Jordão and Roxo (bread); Marialva and Celta (durum) -- have been selected for supplementation trials, following the same agronomic practices and field schedules as the regular (non-supplemented) crops of the same varieties (seed planting: November 2010; crop harvesting: July 2011). Soil additions were performed at sowing time, using sodium selenate and sodium selenite solutions equivalent to field supplementation rates of 4, 20 and 100 g of Se per ha. Total Se in field samples was determined by cyclic instrumental neutron activation analysis, via the short-lived nuclide 77mSe (half-life time: 17.5 s) at the Technological and Nuclear Campus (Portugal), and by radiochemical neutron activation analysis, via the long-lived nuclide 75Se (half-life time: 120.4 d) at the Nuclear Physics Institute (Czech Republic). Quality control of the procedures was regularly asserted through analyses of NIST-SRM 1515, NIST-SRM 1567a and NIST-SRM 8433. Results show that soil supplementation at top rate can increase Se contents in mature grains up to 2, 16, 18 and 20 times for Jordão, Roxo, Marialva and Celta, respectively, when compared to grains from non-supplemented crops. These findings are also discussed with respect to Se-biofortification data from another field experiment, in which wheat crops were grown under an alternative Se-supplementation method (foliar application).
Speaker: Ms Catarina Galinha (CERENA-IST, University of Lisbon)
• 64
Sequential determination of 90Sr, 239Pu and 241Am in urine
Urine analyses can be used to assess the performance of the radiation protection control practices. The separation methods used for estimation of radionuclides in urine are often time consuming and of lower sensitivity. The determination of low levels of actinides and strontium in biological samples require lengthy and tedious chemical processes, which include pre-concentration of samples, radiochemical separation, and source preparation. The determination of radionuclides in samples of urine thus requires fast approach due to radiotoxicological nature of Am, Pu and Sr to human body. In recent years, many studies have applied extraction chromatography to radionuclide isolation from urine samples. In our work, molecular recognition sorbents AnaLig®Sr-01 and AnaLig®Pu-02 from IBC Advanced Technologies, and Eichrom´s DGA® resin were used to effectively and selectively pre-concentrate, separate and determine strontium, plutonium and americium in urine samples. Method employs four-columns separation consisting of four different commercial products. First is Eichrom’s Pre-filter Material, that removes organic compounds present in urine, which interfere with separation and decrease specific radionuclide sorbtion efficiency. This step improves reduction of carry over between columns in tandem and simplyfies whole separation method that is absent of difficult sample pretreatment steps for coloured material elimination used in other works. After passing through the Pre-filter Material column, urine samples are sequentialy loaded onto second and third column, containing one of the AnaLig® series sorbent, that contain specific crown-ethers, and on fourth, stacked with DGA® resin (branched) in which the extractant system is N,N,N’,N’-tetrakis-2-ethylhexyldiglycolamide. Before analysis, samples of urine are acidified with concentrated nitric acid to acquire final concentration of 2 M. Volumes of urine samples varied from 50 ml to 200 ml. Depending on volume, various amounts of NaNO2 were added to secure oxidation of Pu3+ to Pu4+ form, obtaining three different oxidation states for each used radionuclide, in our case Sr2+, Am3+ and Pu4+. These are selectively captured on specific column, providing easy way for separative determination of harmful radionuclides in one sample at once. Radionuclides in columns were eluted with certain volumes of 0.05 M Na4EDTA for AnaLig®Sr-01, 9M HCl with TiCl3 for AnaLig®Pu-02 and with 0,1M HCl for DGA® resin. Strontium samples were counted repeatedly by Cerenkov counting over a 2 week period to monitor the ingrowth of 90Y on TRI CARB 2900 TR (PerkinElmer), while americium and plutonium samples were measured with ORTEC α-spectrometer 576A. Required time of procedure for 100 ml of urine is approximately 2 hours from collection of urine to beginning of measurement. This sequential method does not use phosphate co-precipitation of strontium or plutonium and ashing steps to remove organic compouds, which rapidly quickens and simplifies analysis process. Method separates Sr, Am and Pu from urine with high chemical recoveries and is suitable for use after accidents or emergency situations. Key words: urine analysis, AnaLig Sr01, extraction chromatography, strontium, plutonium, americium
Speaker: Mr Ján Bilohuščin (Department of Nuclear Chemistry,Faculty of Natural Sciences, Comenius University in Bratislava, Slovakia 842 15)
• Poster Session - Separation Methods, Speciation Gallery

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• 65
A rapid separation method for Pu and Sr-90 in seawater samples for emergency preparedness
Artificial radionuclides are released into the environment as a result of nuclear facility accidents and nuclear weapon testing. Among them, strontium, plutonium and cesium are the most frequently monitored in environmental studies. After Fukushima accident, changes of Cs-134/137 concentrations in seawater adjacent to Fukushima are well documented. However, radiostrontium or plutonium concentrations are poorly reported. It is reason that the chemical separation is necessary to determine strontium and plutonium, being beta/alpha emitters, while preconcentration of seawater for gamma emitters is relatively easy. Sequential separation method of Sr and Pu in seawater is studied to prepare for emergency. In general, 50~100L of seawater was needed to determine environmental level of strontium or plutonium in seawater. Casauberta (2013) reported that Sr-90 concentrations were increased by 80 times rather than background levels in Pacific oceans (1.2 Bq/m3) after the accident. At the emergency, 10L of seawater is enough to estimate the impact of the accident. We developed the rapid separation method of Sr and Pu in 1L of seawater and applied it for 10L of seawater. Co-precipitation and extraction chromatography (TEVA, Sr-resin) were used for preconcentration and chemical purification of target radionuclides. And precipitates were dissolved in 8M HNO3, and passed through TEVA resin and Sr-resin, in order. TEVA resin does not hold Sr in the 8M HNO3 medium, while Pu shows maximum uptake. A modular automated radionuclide separator (MARS) developed by our laboratory was applied for purification of Pu and Sr-90. Automated approaches show high potential applicability in emergency preparedness in terms of reducing labor, costs, worker exposure and high throughput. For 1L of seawater, yield of Sr and Pu is 90% and 82%, respectively and finished within 3hrs. The separation of Pu and Sr-90 in 10L of seawater was finished within 10 hrs and yield of Sr and Pu was 60% and 55.2%, respectively. References: Casacuberta et al. 90Sr and 89Sr in seawater off Japan as a consequence of the Fukushima Dai-ichi nuclear accident, Biogeoscinece, 2013, 10, 3649-3659.
Speakers: Dr Geun Ho Chung (Korea Atomic Enegery Research Institute), Dr Hyuncheol Kim (Korea Atomic Enegery Research Institute)
• 66
A Study on Arsenic Speciation in Korean marine samples using Ion Chromatography-Inductively Coupled Plasma Mass Spectrometry
As the toxicity of certain element depends very heavily on their physico-chemical form, it is important to be able to monitor levels of the individual species. Arsenic occurs everywhere in the environment in various forms, including trivalent and pentavalent states, inorganic and organic compounds. In general, pentavalent arsenic is considerably less toxic than trivalent arsenic; inorganic arsenic is more toxic than methylated and other organo-arsenicals. Arsenic speciation in food and dietary supplements is essential in order to provide a meaningful assessment of exposure due to differences in toxicities of the chemical forms. In this study, ion chromatography has been coupled with mass spectrometry to quantitatively determine arsenic species in Korean marine samples We made use of Inductively Coupled Plasma-Mass spectrometry as a sensitive elemental detector in combination with a selective separation technique such as ion chromatography provides information on the chemical form of arsenic compound in some samples. The standard seven arsenic species of Arsenite (As3+), Arsenate(As5+), AsC (arsenocholine), DMA (dimethylarsinic acid), MMA (methylarsonic acid), AsB (arsenobetaine) and TMAO (trimethylarsine oxide) were separated with chromatographic methods, then the arsenic species were selectively detected by ICP-MS. Various extraction procedures were also investigated using reference materials to evaluate the extraction efficiency of the different arsenic species in Korean marine samples
Speaker: Dr Lee Joung Hae (Korea Research Institute of Standards and Science)
• 67
A use of iron(III) hydroxo complexes for removal of radionuclides from solution in the presence of complexing anions
Operation of nuclear power plants and other nuclear industry require solution of the following issues: decontamination of the main equipment and working area, treatment of low radioactive waste (LRW). These problems are closely related to each other, i.e. ineffective treatment of LRW generates large amounts of radioactive waste with complex chemical composition. Behaviour of radionuclides in such processes as sorption, ion-exchange, ultrafiltration, etc., which are used for removal of radionuclides from solution, is largely determined by their speciation in solution. Speciation of iron (III), cobalt (II) and manganese (II) in aqueous solution was studied. A pH range of existence for mononuclear and soluble polynuclear hydroxo complexes, as well as colloidal particles in the media of weak and strong complex anions was found. It was shown that the presence of complex anions (oxalate, phosphate, iodate, EDTA etc.) affects the hydrolysis and precipitation of metal ions in aqueous solution. The presence of complex anions in aqueous solution shifts the beginning of the radionuclides (60Co, 54Mn, 109Cd, 65Zn) coprecipitation with iron (III) to higher pH values. The higher the concentration of the complex anion in solution, the higher pH is needed for coprecipitation of the radionuclides. A treatment technology of aqueous solutions with complex chemical composition, containing different radionuclides (60Co, 54Mn, 109Cd, 137Cs, 110mAg, etc.) as well as used deactivation solutions and acidic filtrates from separation columns, was developed. It was shown that by coprecipitation with iron (III) and ultrafiltration at certain conditions total decontamination of the solutions from 60Co, 54Mn, 109Cd, 137Cs, 110mAg radionuclides is reached. Therewith, decontamination factor of 1.103 using one stage and of 5.106 using three stages purification for 109Cd were obtained. The results of speciation studies show that iron (III) can be precipitated in the presence of organic complex agents, in a form of iron (III) hydroxide, and the radionuclides can be coprecipitated with it. Therefore, coprecipitation can be used as a possible way for decontamination of the radioactive solutions for removal of radionuclides.
Speaker: Ms Valiantsina Torapava (Joint Institute for Power and Nuclear Research - Sosny, National Academy of Science of Belarus)
• 68
Addition of aluminum salts to water for reducing Co-60 in activated corrosion product deposits on primary system surfaces of nuclear reactor plants.
Radiation situation in occupied areas of nuclear reactor plants is much determined by the activity of loose corrosion product deposits (crud) in the primary system. Co-60 present in crud is the major contributor to personnel exposure because it has a long half-life period and emits hard γ-radiation. Experimental studies have been performed to analyze the possibility of reducing Co-60 in crud on the primary system surfaces. Mechanisms of hydrolysis polymer product formation in mixed nitrate solutions of Fe(III) + Al(III) + Co(II) have been investigated. This hydrolysis process models hydrolysis of corrosion products in the primary coolant water where aluminum salts are added. Analyses have been carried out with gel permeation chromatography and radioisotope and elemental analysis methods. The analysis results show that almost all Co(II) ions which entered hydrolysis polymer products during their initial formation are substituted by aluminum ions as the polymer products age. Since these polymers are precursors to occurrence of loose corrosion product deposits on the primary system surfaces and these deposits include Co-60 as the most important source of radiation exposure, the analysis data attributes improved radiation situation in the occupied areas to addition of aluminum salts to the primary coolant water and demonstrates the usefulness of this addition.
Speaker: Mr Timofey Epimakhov (Vitalevich)
• 69
Adsorption of selected fission products on titanate nanotubes
Inorganic ion exchangers are widely used in the treatment of reactor coolant and aqueous nuclear wastes due to their high selectivity, radiation resistance, thermal and chemical stability. Among other inorganic sorbents, hydrous titanium dioxide was proposed as the prospective sorbent for the efficient separation of fission products such as 137Cs and 90Sr. Recently, new forms of nanometer-sized titanate with unique ion exchange properties were obtained. The physicochemical properties of nanostructured titanates are enhanced and the relation between properties and applications is extended. The aim of our work was studies of ion exchange properties of titanate nanotubes in relation to 137Cs and 85Sr. In the present work we synthesized titanate in nanotube form using hydrothermal procedure. Anatase was heated at the temperature of 140 °C in the 10 M NaOH solution for 24 h. The size and shape were characterized by SEM and TEM methods. The specific surface area was measured by BET technique and the pore size distribution by BJH method. The sorption kinetics studies on titanate nanotubes of 137Cs and 85Sr in form of chlorides were measured in 0.1 M NaNO3 solution. Additionally, the effect of sodium and potassium nitrate concentration and pH on 137Cs and 85Sr sorption were examined. The structure of nanotubes was confirmed by XRD, SEM and TEM methods. The particles diameter was greater than 5 nm and length greater than 100 nm. The measured specific surface area was ca. 300 m2∙g-1 and pore size distribution was equal 0.50 m3∙g-1. Due to high porous structure ion exchange kinetics were relatively slow for Cs+ and Sr2+, but 60% of equilibrium was reached within 1 h. The increasing concentration of Na+ favoured 137Cs sorption than 85Sr. As expected, K+ cations influence on sorption was greater. An increase in Kd value with increasing pH was observed for 85Sr, while in the case of 137Cs the highest sorption was reached at pH 7-9, and at pH higher than 9 the Kd decreased. The results suggest possible applications of titanate nanostructures as inorganic sorbents for the efficient separation of fission products from different liquid wastes, however further studies are necessary. The work has been carried out within the strategic research project entitled "Technologies for the development of safe nuclear energy", phase 7, research task nr 4 (SP/J/4/143 321/11).
Speaker: Dr Seweryn Krajewski (Institute of Nuclear Chemistry and Technology, Warsaw, Poland)
• 70
Analysis of the factors that may lead to misinterpretation of U(VI) complexes time-resolved laser-induced fluorescence spectroscopy data
The aqueous chemistry of Uranium(VI) determines its migration in geosphere under oxic conditions and the efficiency of some technological processes like in situ leach uranium mining, thus being extensively studied in geochemistry. Time-resolved laser-induced fluorescence spectroscopy (TRLIFS) is a powerful method that allows one to determine U(VI) speciation both in aqueous solutions and at mineral-water interfaces. TRLIFS makes use of the sensitivity of U(VI) complexes photophysical parameters (excited state lifetimes and positions of maxima in fluorescence emission spectra) sensitivity to its coordination. Because of high sensitivity and selectivity, this method is extensively used in investigation of various systems containing U(VI), including equilibrium constants determination and monitoring U(VI) speciation in drainage waters. At the same time, the values of excited state lifetimes of, e.g. uranyl fluoride and sulfate complexes, obtained by different groups differ significantly. Moreover, even the question about the number of components required for fluorescence decay curves fitting is not clear: some researchers consider discreet lifetimes for different complexes, while others postulate a continuous dependency of lifetime on ligand concentration and interpret their data under the assumption of fast ligand exchange. Here, we’ll present the extensive study of the reasons that may lead to the discrepancy of photophysical parameters obtained for the same complexes. First, recently, we have demonstrated that the effect of excited states annihilation may influence the shape of fluorescence decay curves at high excitation intensities, thus leading misinterpretation of fluorescence decay rates. Second, different algorithms of fluorescence decay curves processing (the use of fixed lifetimes, global analysis etc.) may provide different values of complexes amplitudes and, consequently, equilibrium constants. Third, we’ll demonstrate the influence of ionic strength of the solution on U(VI) complexes photophysical parameters and stoichiometry by the example of uranyl sulfate complexes.
Speakers: Dr Evgeny Shirshin (M.V. Lomonosov Moscow State University), Dr Vladimir Petrov (M.V. Lomonosov Moscow State University)
• 71
A variety of aqueous radioactive wastes are generated during the operation of reactors and other nuclear fuel cycle facilities. The evaporation of low level effluents is a common operation that gives rise to such wastes in a form of evaporator's concentrates. Concentrated aqueous wastes from a number of sources have variety of chemical/radiochemical composition. Such solutions contain high concentration (10 ÷ 500) g∙L-1 of dissolved salts. The radionuclides present in these wastes, also known as wet solid wastes, included fission products, activation products and actinides. Due to their composition and activity, they are adjusted to the form suitable for long-term storage in appropriate repositories. The extraction chromatography is a good alternative for separation of radionuclides from these radioactive wastes. The purpose of this study was to develop suitable and advanced analytical separation procedure of 237Np, 239,240Pu, 238Pu and 241Am for their determination in evaporator's concentrate which results from waste management operations at commercial Nuclear Power Plant. The extraction chromatography with commercial available resin AnaLig®Pu02 was a method used for the separation of 237Np, 239,240Pu, 238Pu and 241Am from simulated evaporator's concentrate samples and actual evaporator's concentrate from Mochovce NPP, Slovakia. Currently, there are two units in operation at Mochovce NPP. The other two units are under construction. The reactors are of the Russian WWER-440 design. The predicted overall production of concentrates from four reactors at Mochovce NPP is 600 m3 per year. The evaporator's concentrate which is represented by fluids of dark brown colour belongs to the most difficult sample of analysis. Samples of WWER-type units contain a high content of boric acid with concentration of borates up to 100 g•L-1. Borates tend to precipitate from solution when there are changes of pH. Solubility of boric acid and borates generally increase with increasing temperature. At pH > 10, boric acid is in the meta borate form [B(OH)4]- with solubility of (14 ÷ 34) wt % from 0 to 50°C. The specific activity lies in the range between (3.7 ÷ 7.4) x 107 Bq∙L-1. For this reason, treatment of the sample is very important. The pH of samples of model and actual solution of evaporator's concentrate was adjusted to ~ 13 by adding of NaOH because of higher solubility of borate solution. There was a method developed on the model samples of 5 mL volume and hence applied on actual solution of evaporator's concentrate of the same volume as well as conditions of separation were optimised. Samples were spiked with 237Np, 241Am and 239Pu to determine the radiochemical yields of separation procedure. After evaporation, sample was dissolved in 4 M HNO3. AnaLig®Pu02 resin can only extract tetravalent actinides, oxidation states of monitored radionuclides were adjusted by adding of 0.5 g NaNO2 and sample was transferred to a column. The success of the separation process depends on choice of suitable elution agent. Americium was eluted with 8 M HNO3, plutonium with 0.5 M NH4I in 7 M HCl and neptunium with 9 M HCl with addition of TiCl3. ORTEC 576A α-spectrometer equipped with ULTRATM ion implanted silicon detectors (600 mm2 active area) was used for counting the alpha radioactivity. The spectra were processed by using the Alpha-vision TM 32-bit emulation software from the EG&G ORTEC company. This method reduces analysis time, cost, labour, organic solvent consumption and disposal and provides high radiochemical yields. Key words: radioactive wastes, extraction chromatography, americium, plutonium, neptunium, tracer techniques, alpha spectroscopy
Speaker: Mrs Veronika Drábová (Department of Nuclear Chemistry,Faculty of Natural Sciences, Comenius University in Bratislava, Slovakia 842 15)
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Automated plant for removing radionuclides from liquid radioactive waste by reverse osmosis
Liquid radioactive waste (LRW) can contain large amounts of emulsified petroleum products and suspended corrosion particles on which radionuclides concentrate. The optimal approach to removal of radionuclides in different physicochemical forms is using adsorption methods together with baromembrane methods such as microfiltration, ultrafiltration, and reverse osmosis. Alexandrov NITI has developed an automated reverse osmosis plant system with remote monitoring and control features including cleaning of reverse osmosis elements. The plant comprises a microfilter, reverse osmosis filter (ROF), unit for cleaning the reverse osmosis elements, low-pressure pump, high-pressure pump, chemical analysis unit, control unit and power control unit. The plant has a filtration capacity of 500 l/h, operating power of 5 kW max, operating pressure of 5 MPa max (at ROF) and removes at least 95% of dissolved salts from LRW with a salt concentration of 10 g/l max and activity up to 10 kBq/l and produces concentrated solutions of up to 50 g/l salt content. The cleaning unit is designed to prepare maximum 150 liters of washing solutions heated to 35оС and clean the reverse osmosis filter. The reverse osmosis elements are cleaned every day using the final water of the plant system and every month using chemical solutions prepared from the final water. The most efficient washing solution is 1.5% solution of citric acid with рН = 4-5. The plant performance is monitored by measuring the solution conductance with the chemical analysis unit and the treatment process is automatically controlled by the control unit equipment. The control and monitoring process does not require presence of the operator in the plant equipment location area. The plant operation is controlled remotely from the operator workstation in another room where the dose rate is below 0.6 μSv/h. Experiments demonstrated that the general demineralization efficiency of the plant was about 75. The system removed almost all petroleum, surfactants, and corrosion products. Alkali metals were removed by ion exchange (pH is reduced). At the same time, the efficiency of radionuclide removal was higher than the general demineralization efficiency. The reverse osmosis efficiency for removal of radionuclides was almost 1000 and even reached the value of 10000 for Sr-90. The chemical cleaning removed fouling consisting of 85% calcium, about 5% magnesium, about 5% iron, and about 1.5 % aluminum species. The specific activity of the washing solutions was 1∙106 Bq/l max with Sr-90 being the main source.
Speaker: Prof. Vitaly Epimakhov (Nikolaevich)
• 73
Characterization of a TBP Resin and development of methods for the separation of actinides and the purification of Sn
TBP is a widely used extractant in liquid–liquid extraction, especially in the extraction of actinides, one of its most prominent examples being the Purex process. A TBP based extraction chromatographic resin has been characterized with respect to its U capacity and the weight distribution ratios (DW) of U, Th, Pu, Np and numerous other cations in different concentrations of HNO3 and HCl. Based on obtained data methods for the separation of Pu from Th and U, and for the purification of Sn, with special focus on decommissioning and radionuclide production, have been developed.
Speaker: Dr Steffen Happel (TrisKem International)
• 74
Combined, sequential procedure for radiochemical analyses of 63Ni, 99Tc, Pu, Th, Am, U and 90Sr in environmental samples
Environmental samples are sometimes quite unique – the mass of sample collected frequently on remote locations is limited due to need of transportation by hands. The advantage of analyses of as much as possible radionuclides is obvious. The information obtained from ratios between different nuclides are enlarging our knowledge a lot. Moreover, the efforts devoted for dissolution of sample sometimes are large. All this supports concept of developing a single, sequential radiochemical procedure, which applied to a single environmental sample, after single mineralization can give information on many radionuclides. In our laboratory from many years a sequential procedure for radiochemical analyses was developed. Recently sub-procedures for 63Ni and 99Tc were included into existing large sequential procedure for Pu, Th, U, 90Sr radiochemical analyses in environmental (soil, sediment, peat etc.) samples [1]. Soaked with ammonia sample (~10g) is ashed in 400 °C sample (about 10 g). Then tracers are added and wet complete digestion is applied using HF, HNO3, HCl and H3BO3. Sample is converted to 1 M HNO3 and then it is neutralized up to pH=6 using ammonia. Precipitation contains all actinides and 90Sr whereas Tc and Ni stay in solution. Actinides are then separated using Dowex-1 and TEVA resins and 90Sr using Sr-Resin. 63Ni is separated using DMG and 99Tc using TEVA. Procedure was positively tested using reference materials spiked with 95mTc (obtained with AIC-144 cyclotron by us) and NiCl2 as tracers only for radiochemical yield tracing due to lack of RM with certified values for 99Tc and 63Ni) . Works were carried out under the strategic research project “Technologies supporting the development of safe nuclear power” financed by the National Centre for Research and Development (NCBiR). Research Task “Development of methods to assure nuclear safety and radiation protection for current and future needs of nuclear power plants”, contract No. SP/J/6/143339/11. References 1. E. Łokas, J.W. Mietelski, K.Kleszcz, E. Tomankiewicz (2010), Nukleonika 55 (2) 195-199.
Speaker: Prof. Jerzy-Wojciech Mietelski (The Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences (IFJ PAN))
• 75
Effect of environmental conditions on the sorption behavior of radiocobalt(II) onto permutite studied by batch experiments
Speaker: Mr Xianghai Zhao (School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049, P.R.China)
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Effect of mobile phase salinity on the Ac-227/Ra-223 generator.
Radium-223 is the first approved alpha emitting radionuclide for use in radionuclide therapy [1]. Radium follows the Calcium metabolism and thus is self targeted to bones. Several generator systems were described in the past [2]. In this study we have focused on a generator system described by Guseva et al. [3], based on a Dowex-1 resin and a mixed methanol/ nitric acid mobile phase. The effect of NaCl addition into a mobile phase on Ac-227/Th-227/Ra-223 generator was studied. The aim of this study was to increase the efficiency of Ra-223 elution and improvement of the Ra-223 elution peak shape. Possible Th-227 breakthrough was also evaluated. Acknowledgement This work was supported by the Ministry of Education Youth and Sports of the Czech republic, grant No.: LK21310. References 1. Xofigo®, European pharmacopoeia Reg. No.: EU/1/13/873/001 2. McAlister, D. R., Horwitz, E.P.: Chromatographic generator systems for the actinides and natural decay series elements. Radiochimica Acta 99, 151–159 (2011). 3. Guseva, L. I., Tikhomirova, G. S. and Dogadkin N. N.: Anion-Exchange Separation of Radium from Alkaline-Earth Metals and Actinides in Aqueous-Methanol Solutions of HNO3. 227Ac - 223Ra Generator. Radiochemistry 46, 1, 58-62 (2004).
Speakers: Dr Jan Kozempel (FJFI CVUT), Ms Lucie Kománková (FJFI CVUT)
• 77
Effect of Thermal Treatment on Chemical Stability of Resorcinol-Formaldehyde Resins and Their Cs-137 Uptake Properties
Here we present the results of study of interrelations between thermal solidification and selective sorption properties of resorcinol-formaldehyde resins of resol type in highly mineralized alkaline media. Using thermal analysis we have observed a series of exo- and endothermal effects, determined the maximum temperature of thermal treatment, and revealed features of resin solidification in Na- and K-forms. Investigations of Cs-137 sorption under static conditions have shown that resorcinol-formaldehyde resins heated at 100-130°C have low chemical stability in 0.1M NaOH solutions, which has a negative impact on Cs uptake. The increase of temperature during thermal treatment stage results in the increased chemical stability and the selectivity of cesium sorption in highly mineralized alkaline media. We believe that this process is related to the decomposition of methylol groups of resitols under elevated temperature and to the formation of new reaction centers, which finally leads to formation of resitols with highly cross-linked polymer network. Such structure determines high selectivity of the resin to cesium and its stability in alkalines.
Speaker: Dr Dmitry Marinin (Institute of Chemistry FEBRAS, Vladivostok, Russia)
• 78
Extraction and separation of cesium and strontium by crown ethers in organic solvents
Extraction and separation of cesium and strontium is an important issue in radiochemistry, how to solve problems relative to the treatment of liquid radioactive waste (LRW), and for analytical purposes. The best extractants suggested for solving this problem are solutions of crown ethers in organic solvents. This paper presents the results of researches on the extraction of cesium and strontium by various substituted crown ethers from nitric acid solutions, and also from neutral solutions in the presence of activating additives. The following macrocycles: dibenzo-18-crown-6 (DB18C6), dibenzo-21-crown-7 (DB21C7), dibenzo-24-crown-8 (DB24C8), 4,4'(5')-di-tert-butyldibenzo-18-crown-6 (DTBDB18K6), dicyclohexyl-18-crown-6 (DCH18C6) and 4,4 '(5')-di-tert-butyldicyclohexyl-18-crown-6 (DTBDCH18K6) were examined. Polar solvents: 1,2-dichloroethane (DCE), nitrobenzene (NB), chloroform (CL), 1,1,7-trihydrododecafluorheptanol (FH) were selected for researches. The effect of the crown ether structure, the solvent nature and the acid concentration was determined in the extraction of cesium and strontium from nitric acid solution containing 100 mg/L Cs and Sr and 0.1 - 5 mol/L of HNO3 into 0.1 mol/L crown ethers in organic solvents. It has been established that all investigated dibenzocrown ethers considerably extract cesium and don’t extract strontium. At the same time dicyclohexylderivatives are the effective extractants for strontium and don’t extract cesium. The dependence of the distribution coefficients of metals (DCs and DSr) on the concentration of nitric acid has an extreme character with the maximum at 1 - 3 mol/L HNO3 depending on the solvent nature. The difference in the extraction ability of dibenzo- and dicyclohexylderivatives of crown ethers may be used for the separation of radionuclides of cesium and strontium from nitrate media. Also, the processes of extraction of cesium and strontium by 0.01 M solutions of macrocyclic polyethers in organic solvents from neutral nitrate, chloride and sulfate aqueous solutions in the presence of activating additives were studied in this work. Under these conditions, DCs and DSr in the absence of activating additives are close to zero for all examined crown ethers. The introduction of various metal salts as activators into the extraction system doesn’t change this situation. Only in the presence of lithium bis(trifluoromethylsulfonyl)imide (CF3SO2)2NLi both dibenzo and dicyclohexylcrowns extract cesium from the aqueous in to the organic phase with noticeable DCs. Under these conditions strontium is extracted insignificantly only by dicyclohexylderivatives. Our studies have shown that the application of the proposed (CF3SO2)2NLi activator allows to solve the task of the efficient separation of cesium and strontium by extraction with dibenzocrown ethers from neutral solutions. These systems can be used for developing analytical techniques and solving problems in radiochemistry.
Speaker: Ms Nadezhda Tsarenko (JSC «Scientific-research institute of chemical technology»)
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Innovation in metrology: fast automated radiochemical separation for strontium 89 and 90
Measuring radioactivity in food and for radiological monitoring of the environment around Nuclear Facilities or mining sites purposes requires a quantification of the radioactive isotopes (especially beta emitters) present in the different compartments (liquids or solids). Strontium 89 and 90 [1], both pure beta emitters are radioactive isotopes of interest. Because of their toxicity and the similarity of their chemical and physical behavior with calcium, these elements may be found through the food chain. After the Fukushima accident, the necessity of a rapid quantification of radioactive isotopes such as strontium 89 and 90 appeared. The new technique developed deals with the determination of the activity concentration of strontium 89 and 90 in water. It includes two steps: the chemical separation by ionic chromatography and the measurement of the activity concentration of strontium 89 and 90 by Cerenkov Effect. In this poster, this chemical separation by ionic chromatography is explained. An automated separation has been developed and allows isolating strontium isotopes, including the radioactive ones: strontium 89 and 90. The separation can be done within one hour. It was achieved through the adaptation of existing analytical chemistry equipments with on-line couplings [2]. The protocol of separation is based on the use of ions exchange columns of Ionic chromatography, not as a separation and measurement technique of the cation but only as a separation technique. At the release time of the ion to be quantified, a fraction collector allows its recovery. The test portion collected is then analyzed with appropriate measurement techniques (radioactive measurement with a liquid scintillation counter (LSC) or mass spectrometry) to determine the activity concentrations of strontium 89 and 90. The results presented at the 17th Radiochemical Conference are linked to the development of the chemical separation of strontium by ionic chromatography. Studied parameters such as the collection time, the test sample volume, the resin capacity will be discussed. This optimized protocol was then tested with standard solutions and proficiency test samples. [1] Tovedal A, Nygren U, Ramebäck H. Methodology for determination of 89Sr and 90Sr in radiological emergency: i. scenario dependent evaluation of potentially interfering radionuclides. Journal of Radioanalytical and Nuclear Chemistry 2009; 282(2): 455–459. [2] L.Lazare, C.Crestey, C.Bleistein: Measurement of 90Sr in primary coolant of pressurized water reactor. Journal of Radioanalytical and Nuclear Chemistry 2009, 279(2): 633-638.
Speaker: Céline AUGERAY (IRSN)
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Investigation of uranium sorption on materials prepared from tetra-n-butylorthotitanate using LSC and TRLFS
Separation of uranium from natural and waste water is a problem, which has been studied for a long time. For such purpose, many organic and inorganic sorption materials have been proposed and titanium dioxide have shown quite promising results. The first aim of this study was to test and characterize sorption materials based on TiO2 prepared from tetra-n-butylorthotitanate (TBOT) in order to optimize their preparation. The second aim was to implement direct hydrolysis of TBOT in the solutions containing uranium as a method for uranium separation. Sorption capacities of six prepared materials were deduced from their sorption isotherms with fixed uranium concentrations (10 mmol L-1) and variable values of V/m (50 – 400 mL g-1). In the direct hydrolysis experiments, the uranium solutions of 20 and 0.05 mmol L-1 were used. After proper multistage separation, uranium in the samples was measured using liquid scintillation counting and time-resolved laser-induced fluorescence spectrometry which together covered the concentration range of uranium in the samples from tens nmol L-1 to hundredths of mol L-1. For three of the six studied materials, the uranium sorption was studied in more details. In the following experiments, the option of direct hydrolysis of TBOT in the sample was tested. This fast way of uranium separation, which could be suitable for in situ separations, was investigated at various conditions. The results were then compared with the classic sorption method of contacting uranium solutions with pre-prepared, solid absorbers based on TiO2 at similar conditions. It was found that the method of direct hydrolysis in the sample is more efficient separation step than the classic sorption, but it fairly depends on the conditions of the procedure itself.
Speaker: Mr Jakub Raindl (KJCH - FJFI - ČVUT)
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Iodine Adsorption on Modified Nickel Oxide
One the most inportant fission products, considered in radiaoctive waste disposal, is is radioiodine (131I). The most notable iodine radioisotopes are 131I and 129I, with half-life 8 days and 15.7 million years respectively. They have potential radiological effect on the human body and the environment due to of their large nuclear yield, volatility and especially accumulation in thyroid tissues. Therefore it is necessary to control their release from nuclear power plants and potentially from disposed radioactive waste. The efficient adsorption unit for the atmosphere cleanup system is needed to capture the iodine isotopes. Activated carbon as adsorbent is widely utilised for this purpose. However, activated carbon has poor iodine retention at higher temperatures which are necessary during waste treatment. Another disadvantage of activated carbon is ignition change in presence of nitrogen oxides. Therefore, the development of new thermally stable adsorbents is envisaged. In presented work, nanomaterials, based on pure nickel oxide, mixed nickel zinc oxide, or nickel oxide doped with silver were developed and tested as potential adsorbents for efficient iodine removal. Simple metal oxides exhibit sufficient radiation and thermal stability. Further improvement of sorption properties may be gained by the functionalisation of nanofiber materials with nickel oxide. Tested powders were produced by photoinduced precipitation of solid precursors from aqueous solutions containing soluble nickel salts, followed by low temperature calcination. The sorption properties of nanomaterials were tested by the method based on Standard Test Method for Nuclear-Grade Activated Carbon (ASTM D3803). In comparison with commercially available nickel oxide, newly developed materials show significantly higher sorption capacity. Acknowledgements: We thank for the support from Ministry of the Interior of the Czech Republic (Project No. VG20132015132).
Speaker: Dr Lórant Szatmáry (ÚJV Řež, a.s.)
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Kinetic and Thermodynamic Modeling Approaches of Selenium by Man-Made and Natural Geological Barriers for Nuclear Waste Management
Some components of nuclear wastes like 79Se should be taken into consideration due to extremely long half-lives and potential migration ability through the environment. Clay minerals are suggested as a barrier material in radioactive waste management; however they have some deficiencies to retard anionic radioisotopes like selenium due to structural properties. Modification of these minerals may help to improve their retardation ability toward these anionic radioisotopes. There are two predominant reasons for limiting selenium in water: a major limiting factor is the possible damage to plants and crops and selenium can represent reproductive dangers for human. The study of sorption kinetics is significant as it provides valuable insights into the reaction pathways and into the mechanism of sorption reactions. The reaction can be defined by a sequence of processes that control the rate, diffusion of ions through particle film, diffusion through the particle and chemical reaction with the functional groups. This paper is dedicated to kinetic performance for selenium removal by selenium selective adsorbent. Batch kinetic experiments were performed using a solution containing 250 mg Se/L (pH 4.0) and 40 mg of inorganic pillared bentonite (OPBent) at three different temperatures and at a certain shaking rate. The selenium concentrations of the samples were monitored by taking the samples from the solution at defined times. The samples were analyzed by high resolution gamma spectroscopy system. The kinetic data obtained were evaluated using classical kinetic models and diffusion/reaction models. The transport mechanism of selenium which comprises a diffusion process from aqueous phase to organo-inorgano-bentonite was described by two kinetic models consisting of derived equations: the homogenous particle diffusion model (HPDM) and the shell progressive model (SPM). The effective particle diffusion coefficient Deff values derived from both the HPMD and SPM equations were compared. The mechanism of selenate sorption by OPBent has been postulated from the experimental results.
Speaker: Ms Ruveyda Kubra Ileri (Istanbul Technical University, Energy Institute)
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Liquid Radioactive Wastes Treatment With Further Immobilization of Radionuclides into Mineral-Similar Sorbents
Sorption method of liquid radioactive wastes (LRW) treatment with further immobilization of radionuclides into mineral-similar sorbents is suggested in this work. Described method can be used for decontamination of LRW from long-lived radionuclides 137Cs and 90Sr; it differs from other methods in higher efficiency of separation of radionuclides as well as in combination of stages of radionuclides concentration and immobilization with the aim of their long-term storage or final disposal. The mixed nickel-potassium ferrocyanide based on hydrated titanium dioxide was used as a sorbent. The method of production of this sorbent is developed by Radiochemistry and Applied Ecology chair of Ural federal university. Spent sorbent meets the demands for matrix materials, therefore, it can be disposed/storaged immediately in hermetically sealed container without additional immobilization into cement matrix, that will allow to reduce volume of RW and decrease storage expense. The possibility of decontamination of wide spectrum of LRW from caesium and strontium radionuclides was experimentally confirmed.The sorbent efficiently extracts radionuclides from neutral aqueous media: the value of distribution coefficient of Cs from tap water is 10(5,6±1,0) mL/g, static exchange capasity of Cs is 270 mg/g; distribution coefficient of Sr is 10(2,9±0,2) mL/g, capasity is not less than 34 mg/g. The sorbent can be efficiently used for extraction of caesium radionuclides from high level acidic (up to 7 M HNO3), saltiness (up to 10 g/L NaNO3) and alkalescent (up to 0,002 M NaOH) solutions. With solution acidity increasing, distribution coefficient of caesium decreases to 3.7•103 mL/g at 3 mol/L of HNO3 and remains almost constant at more acidic solutions. Increasing of NaNO3 concentration up to 10 g/L also leads to decreasing of distribution coefficient of caesium; at NaNO3 concentration up to 300 g/L Kd value remains almost constant on the order of 102,75 mL/g. It is not recommended to use the sorbent alkalescent solutions with NaOH concentration more than 0.01 mol/L in view of partitional destruction of the sorbent. It was shown that the sorbent can be efficiently used for decontamination of Cs-contaminated waters containing surfactants and EDTA. There is no any influence of surfactants on sorption of caesium at concentrations up to 10 g/L. The affect of EDTA on caesium sorption is determined. It is shown, that at initial concentrations of caesium up to 1 mg/L there is no influence of EDTA concentration (up to 0.01 mol/L of EDTA) on sorption of caesium. Distribution coefficient of caesium at 10-3 mg/L of Cs is slightly lower than at 1 mg/L of Cs; the Kd values are respectively 10(4.1±0.2) и 10(4.7±0.2) mL/g. Distribution coefficient of caesium decreases at EDTA concentrations higher than 0.01 mol/L. When initial concentration of caesium is 10-3 mg/L, distribution coefficient of caesium doesn’t depend on EDTA concentration at whole studied concentration range and its value is 102 mL/g. Leaching rates of caesium and strontium from saturated samples of the sorbent were determined. When distilled water was used as a leachant, leaching rates were 3.7∙10-10 to 8.2∙10-12 g/(cm2∙day) for caesium and от 1,8∙10-10 to 1,2∙10-12 g/(cm2∙day) for strontium; for tap water as a leachant leaching rates were 1,4∙10-11 to1,5∙10-12 g/(cm2∙day) for strontium. Thus, it was experimentally confirmed that the sorbent can be successfully used as a matrix material for immobilization of radionuclides.
Speaker: Dr Anna Voronina (Ural Federal University)
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Liquid-liquid extraction of technetium(VII) with TODGA
N,N,N′,N′-tetraoctyl-diglycolamide (TODGA) is broadly studied as a non-specific extractant for actinides and lanthanides from HNO3 solutions of nuclear waste, in particular for group actinide extraction (GANEX process). Unfortunately, some fission products including technetium (in the form of pertechnetate anion, 99TcO4–) are also efficiently extracted from HNO3 solutions to the TODGA-containing organic phase, accompanying the actinides and lanthanides. The present work was focused on modelling the process of technetium extraction to organic solutions of TODGA. The TcO4– anion is evidently extracted to the organic phase as the ion pair, together with a lipophilic cation – the protonated TODGA molecule. We investigated the effects of acidity, of anions that compete with TcO4– for the lipophilic cation, and of diluent on the efficiency of extraction of technetium(VII). The effect of other metals present in the extraction system was also studied. This work was financed from the National Centre for Research and Development through the Strategic Program Technologies Supporting Development of Safe Nuclear Power Engineering, task 4: Development of spent nuclear fuel and radioactive waste management techniques and technologies.
Speaker: Ms Magdalena Rejnis (Institute of Nuclear Chemistry and Technology)
• 85
Long term immobilization of Cs-137 by transformation of titanium ferrocyanide to lithium titanate
Radioactive waste contains a variety of radionuclides and arises in a variety of physical and chemical forms. In Poland, the amount of activity and waste volume of liquid wastes are relatively small, mostly from operation of research reactor. Despite of the low level radioactivity involved, there are many significant hazards that could arise as a result of inadequate management. Treatment of liquid wastes is needed to produce a waste product suitable for long term storage and disposal. Our idea of immobilization of the 137Cs radionuclide in the matrix of TiO2 is based on the initial sorption of 137Cs on titanium ferrocyanide (TCF) and then converting TCF to the TiO2aq by hydroxide solution and calcination of the product to ceramic. We showed that the TCF is a very effective sorbent for 137Cs. In the column experiments we did not observed any breakthrough of the column after passing 10000 bed volumes of the saline solution spiked with 137Cs . After adsorption of the 137Cs on TCF hydroxide solutions were passed through a column and degree of transformation of TCF to TiO2 and leakage from the column was examined. Hydroxides used were as follows : LiOH , NaOH , KOH , and (CH3)4NOH. The obtained results indicate that all hydroxides studied convert, in 100 percent, the black TCF to the white TiO2aq. However, when using NaOH and KOH competing influence of the cations K+ and Na+ causes leakage of 137Cs from formed TiO2 aq. Much better results have been obtained using tetraalkylammonium hydroxide and particularly lithium hydroxide. Competitions from bigger tetraalkylammonium cations and hydrated Li+ on sorption of small hydrated Cs+ cation is negligible. Collected samples of the titanium oxide with adsorbed 137Cs were next calcined at 900oC and the leaching of radionuclides has been studied. Acknowledgments: This work was carried out as part of the Strategic Project ‘‘Safe Nuclear Power Engineering Development Technologies’’ supported by The National Centre for Research and Development, Poland.
Speaker: Prof. Aleksander Bilewicz (Institute of Nuclear Chemistry and Technology)
• 86
Methods for dissolution of [226Ra]BaSO4
Groving interest in the research of radium chemistry, its use as target material in nuclear reaction studies and preparation of calibration sources leads to a higher demand for 226Ra in readily available soluble form. Aged radium needle sources containing very insoluble radiobarite may serve as source material of 226Ra and its decay products (e.g. 210Pb). We descibe here several methods for [226Ra]BaSO4 dissolution including microwave assisted reaction and compare their efficiency in model experiments.
Speaker: Dr Jan Kozempel (FJFI CVUT)
• 87
Nanodiamonds as a prospective sorbent for radionuclides
Detonation nanodiamonds (DND) are potentially promising candidate for sorption applications due to their unique properties: high surface area, highly developed surface, low weight, chemical and radiation resistance. The oxygen-containing groups on the DND surface are responsible for the cation-exchange properties. The sorption capacity of DND is found to be comparable with other carbon nanomaterials as carbon nanotubes and graphene oxide and higher than that of carbon black. The sorption of radionuclides showed to be effected by surface chemistry of DND. It was shown before, that DND can effectively remove U(VI), Am(III), Th(IV), Pu(IV) cations from solutions [1]. In this work the sorption regularities of Th(IV), Ra(II), Ba(II), Ac(III) were studied for different samples of DND: commercially available nanodiamond powder (Sigma-Aldrich) and concentrated suspension, produced at the Special Construction-Technological Bureau "Technolog" of Saint-Petersburg State Institute of Technology (Technical University) (Russia). The radionuclides of interest were chosen with the aim to test nanodiamonds as a prospective sorption material for preparation of 227Ac/223Ra generator. [1] Yu. P. Buchatskaya et al. Proc. of 42èmes Journées des Actinides and 9th School on the Physics and Chemistry of the Actinides, Bristol, England, 2012
Speaker: Ms Yulia Buchatskaya (Czech Technical University in Prague)
• 88
Polyacrylonitrile based composite materials with extraction agents containing chemically bonded CMPO groups for separation of actinoids
Several extraction agents with functional group of diphenyl-carbamoylmethylphosphine oxide were synthetized and tested in the frame of EUROPART project for actinoids partitioning from nitric acid solutions. Functional groups were chemically bonded with a platform of tert-butylcalix[4]arene, O-pentylcalix[4]arene, and cobalt bis(dicarbollide) cluster ion to enhance extraction properties. The extraction agents were used for preparation of composite materials with polyacrylonitrile (PAN) as a binding polymer to study behavior of these composites in column chromatography. They were compared with CMPO-PAN composite material prepared with neat octyl(phenyl)-N,N'-diisobutylcarbamoylmethylphosphine oxide compound (CMPO). Uptake kinetics was studied with europium as an analog of americium. Weight distribution coefficients (Dg) of europium, americium, plutonium, uranium, and neptunium were determined in nitric acid solutions (0.01 - 5 mol/L) in the presence of sodium nitrate (0.1 mol/L). Europium extraction isotherms from 3M HNO3 solution were used for capacity determination.
Speaker: Dr Jan Kameník (Department of Nuclear Chemistry, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, 115 19 Prague 1, Czech Republic)
• 89
Activated carbon can potentially be used as an adsorbent for removing Tc from aqueous solutions. We have prepared and tested five carbon materials for their capabilities for sorption of pertechnetate (TcO4−). A carbon materials were prepared by soaking of fibrous cellulose with different solutions containing inorganic materials suitable for creation of micropores and after drying, material was carbonized at 500-800 oC. Prepared carbon materials were characterized by BET, acid-base titration, XRD and TEM methods. Sorption of TcO4− on carbon sorbents is fast. For some sorbents even 1 minute is enough to reach more than 99% sorption. Sorption of TcO4− is pH dependant. Maximum Kd was in acidic pH (pH 2-3) and reach about 7x104. Kd were decreasing with increasing pH. In sample B sorption of TcO4− was high even at pH 8 (Kd 5x103).
Speaker: Prof. Pavol Rajec (Faculty of Natural Science, Comeniues University, Bratislava)
• 90
Rapid determination of radiostrontium in milk using automated radionuclides separator and liquid scintillation counter
Milk is one of the special important matrices to be rapidly assessed its radioactive contamination in emergency situations such as a nuclear plant accident. Because of its chemical and biological similarities to calcium in milk, radiostrontium can be incorporated into human organism, preferentially in bone tissue, by milk ingestion. Development of rapid analytical methods for radiostrontium in milk is essential for emergency situations. Both 89Sr and 90Sr, produced by the fission reaction of nuclear fuel in a nuclear reactor, are beta emitters which require radiochemical separation for radiometric analysis. The conventional methods for the determination of radiostrontium in milk using time consuming sample preparations and manual chemical separations are usually too slow to take measures for emergency situations. A modular automated radionuclide separator for 89/90Sr (MARS Sr-90) has been developed for the rapid and reproducible isolation of radiostrontium. MARS Sr-90, designed and built in our laboratory, was successfully applied to the isolation of radiostrontium in milk samples. MARS Sr-90 consists of four parts; a control module, a pump module, a valve module and a column module. Control software developed on the LabView platform is a virtual instrument to control MARS Sr-90 by means of manipulating the most important input parameters through the graphical user interface on the computer screen. The automated radiochemical procedures for separation and purification of 89/90Sr in milk are developed. MARS Sr-90 uses cation exchange resin for pre-concentration of 89/90Sr from a milk matrix and Sr-Spec resin for purification of 89/90Sr from interfering radioactive nuclides. By using MARS Sr-90 with rapid flow rates, sample preparation time is minimized. The activities of purified 89/90Sr are simultaneously determined by the measurement of the Cherenkov radiation of 89Sr and liquid scintillation radiation of 90Sr using 1220 Quantulus liquid scintillation counter. The developed automated radiochemical procedures provide a rapid, safe and reproducible separation of 89/90Sr from milk samples. Compared to conventional 89/90Sr separation methods carried out manually, MARS Sr-90 is faster, less labor intensive and expected to be widely used as a powerful and convenient tool for the chemical separation and purification of 89/90Sr found in various foodstuffs for an emergency situation.
Speakers: Dr Hyuncheol Kim (Korea Atomic Energy Research Institute, Environmental Radioactivity Assessment Team), Dr Jong Myoung Lim (Korea Atomic Energy Research Institute, Environmental Radioactivity Assessment Team), Dr Kun Ho Chung (Korea Atomic Energy Research Institute, Environmental Radioactivity Assessment Team)
• 91
Speaker: Prof. Vitaly Epimakhov (Nikolaevich)
• 92
Separation and preconcentration of trace amounts of Sr-90 and Tc-99 from primary coolant water using commercially available sorbents and ion-exchangers.
Among the fission products of U-235 are: Sr-90 and Tc-99. Information on their content in primary coolant water is very important because it indicates the state of the fuel rods in NPP. Different analytical methods could be used for the determination of Tc-99 and Sr-90, however each method requires separation and/or preconcentration of determined radionulide. The problems are also related to large volume of samples, what is the case of coolant water. This study outlines some batch and column studies for selective separation of strontium and rhenium (as an analogue of technetium) using commercially available sorbents and ion-exchangers. Preliminary results suggest, that it is possible to separate strontium and technetium from boric acid (main components of primary coolant water and from other beta-emitters. Acknowledgments: Research task No. 8 „Study of processes occurring under regular operation of water circulation systems in nuclear power plants with suggested actions aimed at upgrade of nuclear safety" partly financed by the National Research and Development Centre in the framework of the strategic research project entitled „Technologies Supporting Development of Safe Nuclear Power Engineering”.
Speaker: Mrs Marta Pyszynska (Institute Of Nuclear Chemistry And Technology)
• 93
Separation of Curium from Americium Using Composite Sorbents and Complexing Agent Solutions
Two liquid liquid extraction processes intended as a part of the Partitioning and Transmutation strategy have been used as a basis for development of chromatographic systems for separation of curium from americium. The liquid organic phase of the EXAm process was replaced by DMDOHEMA-PAN composite sorbent and TEDGA in nitric acid solution was employed as an aqueous-phase complexing agent. The liquid organic phase of the AmSel process was replaced by TODGA-PAN composite sorbent and sulfonated BTBP derivative in nitric acid solution was employed as an aqueous-phase complexing agent. The influence of aqueous phase complexing agent and nitric acid concentrations on weight distribution coefficients and separation factor as well as the kinetics of the actinide uptake were determined in batch experiments with trace amounts of Am-241 and Cm-244 radionuclides. The efficiency of Cm separation from Am was evaluated in column experiments.
Speaker: Kamila Šťastná (Department of Nuclear Chemistry, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague)
• 94
Solvent extraction of plutonium from environmental samples
The solvent extraction was described for determination of the plutonium presented in the environmental samples. Tri-n-octylphosphine oxide (TOPO) and di-2-ethylhexyl phosphoric acid (HDEHP) were used as the significant reagent of extractants of the plutonium. The extraction properties of TOPO and HDEHP for tetravalent plutonium in 5 mol.L-1 HNO3 into toluene were investigated. The optimal concentration of TOPO for extraction of plutonium was determined (1.10-2 mol.l-1 and higher). These solutions are easily measurable by liquid scintillation method without any further adjustment procedures. The dependences of equilibrium ratios of the plutonium on analytical concentration of chelating agents and pH were studied. The structure of the complex in the organic phase was determined as Pu(NO3)4.2TOPO and the value of extraction constant was calculated. Trivalent lanthanides and actinides, important fission products as cesium, zirconium, strontium and also thorium, uranium with concentration up to 1.10-4 mol l-1 and iron with concentration up to 5.10-3 mol l-1 do not interfere. The goal of this work was to develop selective solvent extraction method for the separation of plutonium.
Speaker: Dr Alena Tokárová (University of defense)
• 95
Sorption of U(VI) by Submicron ZnS Particles from Aqueous Solution.
Uranium is one of the most dangerous radionuclides which makes a major contribution to the total alpha-activity of liquid nuclear wastes. The most promising method for the extraction of radionuclides, including uranium from aqueous media is solid phase extraction. In the last time, different inorganic sorbents (including natural zeolites) having certain advantages over synthetic organic ion exchangers are widely used for the liquid nuclear wastes treatment. Inorganic sorption materials have a high chemical and radiation stability and exhibit high selectivity for certain radionuclides which strongly depends on the pH of aqueous media. Among the inorganic sorbents considerable attention paid to the development of fine sorption materials, which open new possibilities for creating highly efficient process units. A feature of such materials is a large ratio between surface area and volume, which can significantly increase their adsorption capacity. Promising compounds that can be used to produce such materials are fine powders of divalent metal sulfides. It is well known that functional properties of sorbents are largely determined by the size and shape of the particles as well as surface morphology. The goal of this work was to obtain fine powders of ZnS and to study their sorption properties towards U(VI) at different pH of aqueous medium. One of the possible ways of using zinc sulfide particles for analytical purposes is the creation on their basis of sorption-scintillator materials for the determination of low concentrations of alpha radionuclides in natural waters. Sphalerite ZnS with the size of particles of 100-200 nm was obtained using the method of chemical deposition from thiourea solutions. Obtained powders were characterized by XRF, SEM and IR techniques. Sorptive properties of ZnS towards U(VI) at pH 2-9 were studied in batch experiments at 25 ºC using the method of limited volume.The time required to establish sorption equilibrium between the solution and the sorbent was determined from the kinetic curves.It was found that sorption equilibrium in the studied system at pH 7 is established during 60-90 min. The concentration of U(VI) in solutions after sorption was determined by a luminescent method.Luminescence spectra and excitation of uranyl ions were recorded using spectrofluorimeters Avantes(Netherlands). Recovery rate of U(VI) in the range of pH 2-9 was 95-99%. Relative measurement error at a confidence level 0.95 didn't exceed 1%. The observed sorption's features of uranyl ions by fine zinc sulfide enable to assume that for this kind of the sorbent may be different types of sorption processes. Structure sulfide sorbents based primarily on close packing of atoms, which are almost always eliminates the formation of voids in the structure of the appropriate sorbents,than for them are less characteristic sorption acts related to the exchange and non-exchange absorption of ions in the structural voids. High recovery rate of uranyl-ions obtained for ZnS fine powders makes possible their use for water decontamination purposes as well as for analytical concentration followed by determination of uranium radioactivity by alpha spectrometry.
Speaker: Ms Anna Rubailo (Yurievna)
• 96
Study of europium and americium uptake on solid extractant with CMPO and polyacrylonitrile from diluted nitric acid solutions
Octyl(phenyl)-N,N'-diisobutylcarbamoylmethylphosphine oxide (CMPO) extraction agent and polyacrylonitrile (PAN) as binding polymer were used for production of CMPO-PAN solid extractant. The material was previously studied for application in column chromatography for actinoids separation [1]. High uptake of americium and europium on CMPO-PAN solid extractant was observed in diluted nitric acid solutions (0.001-0.1 mol/L) contrary to minimal uptake by CMPO itself. A set of experiments was performed for explanation of this effect that cannot be solely explained by adsorption on PAN support. Materials prepared by modification of the original procedure were tested and compared. Influence of CMPO content in the composite and total nitrate ion concentration in the solution on the uptake were determined for several acidities. Selected materials were subjected to FT-IR analysis to study interaction of the support polymer and CMPO agent. Europium extraction isotherms were measured in the solution of 0.01M HNO3 for capacity determination. It was found that addition of sodium nitrate (0.1 mol/L) increases maximum europium capacity by more than an order of magnitude to the value that was determined in 3M HNO3. The observations indicated that europium and americium uptake mechanism on CMPO-PAN is different in solutions with diluted and more concentrated nitric acid and is influenced by total nitrate concentration. [1] Kameník J., Šebesta F. (2006), Czechoslovak Journal of Physics 56, D493-D500. * Present address: Nuclear Physics Institute, Academy of Sciences of the Czech Republic, 250 68 Řež, Czech Republic
Speaker: Dr Jan Kameník (Department of Nuclear Chemistry, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, 115 19 Prague 1, Czech Republic)
• 97
Study of the DTPA and Malonic Acid solution for the selective Am stripping in the CEA EXAm process
Distler P.*, Spendlikova I.*, Burdet F.+, Miguirditchian M.+ *CTU in Prague, Brehova 7, 115 19 Prague 1, Czech Republic +CEA Marcoule, Nuclear Energy Division, Radiochemistry & Processes Department, SMCS/LEPS, Bagnols-sur-Cèze, F-30207, France In the frame of the development of the French CEA EXAm process (Am selective separation from a PUREX raffinate by solvent extraction), the selective stripping of americium from lanthanides was studied using a solution of DTPA and malonic acid. This step is similar to a reverse-TALSPEAK system developed for Am/Ln separation. Organic phase containing 0.3 M HDEHP and 0.6 M DMDOHEMA in TPH was first loaded with the aqueous phase containing Am/lanthanides/fission and/or corrosive products. The loaded organic phase was then contacted with the aqueous solution of DTPA and malonic acid at pH around 2.5. The impact of DTPA and malonic acid concentrations, pH dependence, kinetic and thermodynamic studies were studied on americium and lanthanides extraction. In addition, the impact of the nature of the base used to pH adjustment and the stability constants of DTPA with Am(III), Eu(III) and Ce(III) were determined in process conditions. These results showed that DTPA and malonic acid extraction system can selectively strip Am(III) over lanthanides (Ce(III) and Eu(III)) and other fission products potentially present in organic phase (Fe(III), Y(III)). The results are important for a better understanding of the process chemistry and are used for the modelling and the simulation of this step of the EXAm process.
Speakers: Mrs Irena Spendlikova (CTU in Prague), Mr Petr Distler (CTU in Prague)
• 98
Technetium and Rhenium sulfide nanodispersion size speciation by SAXS, nanosizer and ultramicrocentrifugation.
K.E. German1,2, A.A. Shiryaev1, A.V. Safonov1,2, Ya. A. Obruchnikova1,2,3, V.A. Ilin1,2, M.N. Glazkova2, V.E. Tregubova1,2, S.N. Kalmykov4, E.V Abkhalimov1 1 – Frumkin Institute of Physical Chemistry and Electrochemistry RAS, Moscow, Russia 2 – Moscow Medical InstituteREAVIZ, Moscow Russia 3 – Mendeleev Russian Chemical Technology University, Moscow, Russia 4 – Lomonosov Moscow State University, Moscow, Russia Technetium and rhenium heptasulfides were among the first synthesized compounds of these elements as considered the convenient route for Tc and Re separation from aqueous solutions. Although in the first works its composition was established as M2S7 (M = Tc, Re) it was rather surprising in view of Tc and Re redox potentials being in contradiction with those of S2-. No reasonable thermodynamic data is available on the solubility of these compounds mostly due to the variety of chemical nature ascribed to these compounds and difficulties in its nano- and micoro- size speciation/attribution. Only the formation kinetics and colloidal particle size speciation studies [1-3] provided with some reliable information on Tc concentration dependences. Structure unit fragment Tc3S13 for technetium sulfide acc. to EXAFS studies [4] contained trinuclear Tc(IV) cluster with 3-S atom inside it and the planar vacancies filled with multiple disulfide ligands, thus explaining the excesses of S in this compound. In the growing process of Tc-S colloid system, the size of colloid particles was shown to increases by deposition of Tc sulfide on the particle surface, not by coagulation of the particles [3]. Recently mixed oxo-sulfide species of Tc were characterized [5]. Here we continue microcentrifuge size speciation in course of the reaction of Tc(VII) and Re(VII) with sulfide and follow it with size speciation of generated particles in the solution by SAXS at specialized small angle diffractometer SAXSess (Anton Paar (Austia), CuK (1.54 А), transmission analises after collimation correction mode, sealed glass capillaries, registration with ImagingPlate). Based on Log(I) = f(s2) plots, s = 4πsin(Θ)/λ) for the aged samples two types of species were observed in Re sulfide colloidal solution by SAXS. Small particles were monodisperse and quite isotropic with Rg = 0.31 – 0.45 nm. Large particles were disc shaped with 40 nm in diameter and 5 nm height. Both methods supported induction period and kinetic dependent on the [Na2S] in the solution and the order of mixing the reagents. Based on the similarity of chemical behavior we suggest similarity in composition of technetium and rhenium species obtaind in the identical conditions. The stability of M3S10 (M = Tc, Re) in the resulting solution was dependent of the S2- concentration in it. When higher than 0.06M Na2S, further grouth of Tc and Re sulfide particles occurred for  ≥ 150 h similar to observations made in [3]. For [Na2S] ≤ 0.04 M, the M3S10 was reoxidized by present air to Tc(VII) within 175-200 hours thus being resolubilized. The determination of the free Tc and Re species concentration with separation of ionic or nanocolloidal particles with 5 kD “Sartorius” ultramicrocentrifuge tubes gave evidence on the M3S10 nanosulfide formation similar to that observed in [4]. The equation for the Tc sulfide solubility based on these figures was evaluated. References 1. El-Waer, S., German, K. E., Peretrukhin, V. F. J. Radioanal. Nucl. Chem., 157 (1992) 3–14. 2. K.E. German, V.F. Peretrukhin, D.N. Tumanova, A.Yu. Tsivadze. Technetium sulfides – role in chemistry and ecology. In: 7th International Symposium on Technetium and Rhenium – Science and Utilization – Book of Proceedings - July 4 -8, 2011, Moscow, Russia (Eds.: K.E. German, B.F. Myasoedov, G.E. Kodina, A.Ya. Maruk, I. D. Troshkina). Publishing House GRANITZA, Moscow 2011, p. 181-186. 3. Y. Saiki, M. Fukuzaki, T. Sekine et all. J. Radioanal. Nucl. Chem. 255 (2003) 101–104. 4. W. W. Lukens, J. J. Bucher, D. K. Shuh, N. M. Edelstein
Speakers: Mr Alexey Safonov (Frumkin"s Institute of Physical Chemistry Russian Academy of Science), Dr Konstantin German (Frumkin"s Institute of Physical Chemistry Russian Academy of Science)
• 99
The Formation of Structure in the Extraction at Vibration in an Interfacial Layer
Formation of cruds at the extraction of metals is the negative phenomenon as reduces the rate of extraction, worsens disintegration of the emulsions, and leads to loss extragent and an extractive element. In practice to prevent the formation of structure in an interfacial layer in system aliphatic alcohols add to aliphatic alcohols, for example, octanol - 1. However there are additional losses extragent, threat of environment increases. The results of researches on influence of the mechanical vibrations on an interface on process of the formation of structure in an organic phase at extraction rare-earth elements by solutions di-(2-ethylhexyl)phosphoric acid are considered. Vibration influence on interfacial layers was carried out by means of the vibrator which represented a high-frequency electrodynamic head with rigidly fixed core, by a coming to an end vibrating element in the form of the triangular prism turned to an interface by top. The vibrator connected to the generator of low-frequency signals. The effective viscosity and limiting pressure of shift of organic phase exposed to vibration is constant during first ~15 min. At short time (~5 min), the main contribution in system behavior is provided by spontaneous surface convection. At longer time intervals (50–60 min) when spontaneous surface convection is absent, it is the vibrations that disintegrate the resulting structure. The supply of additional energy into interfacial layers of extraction system changes the hydrodynamic situation not only in interface region but also in the adjacent domains of contacting phases. The relative motion of particles increases when exposed to mechanical action. Since resulting particles have different weight and move with different velocity, their shift leads to is integration of aggregates in temporary structure. Thus, mechanical vibrations disintegrate the structure at the weakest coagulation contacts. However, the viscosity and a limiting pressure of shift of organic phase sharply increases with time. The nascent temporary structure is heterogeneous, therefore the supply of additional energy leads to its disintegration and particles of smaller size prevail in the system. The interaction of reproduced particles results in the formation of a stronger structure. Thus, the local supply of mechanical energy in an interface layer possible to suppress process of the formation of structure during the initial moments of time.
Speaker: Prof. Nikolay Kizim (Fedorovitch)
• 100
The System СА® (analytical Kit “Анфеж®”) for determination of low levels of radiocesium contamination in liquid media.
The recently developed apparatus named System СА® (Kit “Анфеж®”) and the procedure of its effective application for the concentration and determinination of low levels of radiocesium contamination in liquid media is discussed. The liquid media which can be analyzed by the System СА® include sea water, fresh water, drinking water, wine, milk, juice, human urine etc. The apparatus is designated to rapidly estimate radiocesium contamination of individuals by immediate determination of radionuclides in urine samples. Unlike the known analogs, this analytical Kit is cheap and simple in application. The main element of the system is a plastic chromatographic column which contains 10 to 100 g of granulated ferric cyanoferrate. This chemical is absolutely safe and harmless to human health and is widely recommended as an antidote in the case of radiocesium or thallium poisoning. It is shown experimentally that for quantitative determination of background levels of radiocesium in humans, the volume of the sample should be 900 to 1000 ml of urine and the chromatographic pretreatment may take 3 - 5 min. Our research showed that this analytical Kit can be also used for high-speed concentration of radiocesium from large volumes of water solutions (to 1000 l of sea water) during a short period of time (to 30 min). According to the experimental testing, the analytical Kit allows quick transfer of the saturated sorbent from the chromatographic column to a well-type scintillation detector. The shelf life of the Kit is 5 years.
Speaker: Dr Remez Victor (Ecsorb, the Compamy)
• 101
Thermodynamics and separation factor of uranium from lanthanum on gallium-indium eutectic alloy
Actinides recycling by separation and transmutation are considered worldwide as one of the most promising strategies for more efficient use of the nuclear fuel as well as for nuclear waste minimization, thus contributing to make nuclear energy sustainable. With this purpose, two major fuel reprocessing technologies have been explored so far to separate the actinides from the fission products arising from nuclear energy production: hydrometallurgical and pyrometallurgical processes. Fast neutron reactors allow more efficient use of uranium resources. In addition this type of reactors is capable of burning long lived actinides (including those accumulated in thermal reactors spent fuel) thus reducing radioactivity of nuclear wastes. Application of fast reactors results in considerable increase of fuel burn up and, if the reactor is operated as breeder, reproduces fissile materials. At present non-aqueous pyrochemical methods employing molten salts and liquid metals are developed for reprocessing spent nuclear fuels (SNF) of fast reactors. Inorganic melts have very high radiation stability and can be employed for organizing a short closed fuel cycle. Fissile elements and fission products dissolved in a salt melt can be separated employing selective extraction by liquid metals. Detailed information on the properties and behavior of all elements present in SNF in fused salts and liquid metals is required to design a feasible separation process and these include rare earth elements representing an important group of fission products. Behaviour of lanthanum has so far been studied only in binary systems, Nd-Ga and Nd-In and the behaviour of uranium – only in binary systems, U-Ga [4] and U-In. There is no information on thermodynamic properties of lanthanum and on separation factor of uranium from lanthanum on metallic Ga-In alloys. In the present study the base thermodynamic properties of lanthanum and the separation factor of uranium from lanthanum was determined in Ga-In eutectic alloy. For calculation of thermodynamic properties of lanthanum and the separation factor of uranium from lanthanum the galvanic cells (1) and (2) were used: Mo(s) (La}| 3LiCl-2KCl, La(III)|| 3LiCl-2KCl | С(s), Cl2(g) (1) La (alloy) | 3LiCl-2KCl, La(III)|| 3LiCl-2KCl | С(s), Cl2(g) (2) Variation of the apparent standard redox potential of the couple La(III)/La as a function of the temperature is: E*La(III)/La = - (3.731 ± 0.004) + (8.3 ± 0.6)∙10-4T ± 0.003 V (3) Variation of the apparent standard redox potential of the alloy Me(Ga-In) as a function of the temperature were fitted to the following equation using Software Origin Pro version 7.5. E**La(III)/La(Ga-In) = - (2.906 ± 0.003) + (5.72 ± 0.06)∙10-4T ± 0.002 V (4) E**U(III)/U(Ga-In) = - (2.508 ± 0.006) + (3.82 ± 0.11)∙10-4T ± 0.003 V (5) The activity coefficient of the lanthanum in liquid gallium – indium alloy was determined by equation (6): logγLa(Ga-In) = 3F/2.303RT∙(E*La(III)/La – E**La(III)/La(Ga-In)) (6) logγLa(Ga-In) = 3.91 – 12496/T ± 0.08 (7) The expression for calculation of the separation factor (θ) of the metals M1 (uranium) and M2 (lanthanum) on gallium-indium eutectic alloy can be written as: lnƟ = [(n-m)FE + mFE**2 – nFE**1]/RT (8) Using the temperature dependences of the apparent standard potentials of lanthanum (4) and uranium (5) in alloys, the following expression for separation factor of uranium and neodymium was obtained: lnƟ = -6.61 + 13859/T ± 0.02 (9)
Speakers: Prof. Alena Novoselova (Institute of High-Temperature Electrochemistry UD RAS), Prof. Valeri Smolenski (Institute of High-Temperature Electrochemistry UD RAS), Ms Yana Luk’yanova (State Scientific Centre -Research Institute of Atomic Reactors)
• 102
“Separation of Tc radioisotopes from proton irradiated Ru targets by thermochromatography –preliminary results”
Among neutron deficient Tc isotopes, 95mTc is a useful radiotracer due to a relatively long half-life (t1/2=61 d), and high abundance of its gamma-rays. It can be used for studying of a behavior of 99Tc in the environment and waste disposal, as well as in the development of new radiopharmaceuticals of 94m, 99mTc. Radioisotope 95mTc can be obtained by a bombardment of Mo-enriched and Nb targets with protons or alpha particles[1]. In the present work 95mTc was obtained by proton irradiation of natRu targets. Ru or RuCl3 powder with a natural isotopic composition was irradiated. The irradiation condition was 20 nA as proton of energy 60 MeV for 2-3 h at the Cracow AIC-144 cyclotron. At first stage an investigation of volatilization of Tc, Rh and Ru as oxides by heating the target material – RuCl3 powder in an O2 stream was carried out. At second stage, the investigation with Ru powder as target material was done in the same experimental conditions as for studies of RuCl3 as target. The similar thermochromatograms were obtained for carrier-free Rh and macroscopic amount of Ru. One oxide of Rh was detected. Thermochromatogram of macroscopic amounts of Ru oxides showed wide peak in temperature range from 1340K to 300K. This peak corresponds to the oxides: RuO2 and RuO3[2-4]. Two peaks of carrier-free Tc have been observed at 620 K and 320 K for RuCl3 target and one peak at 850 K with right-sided tail for Ru target. Thermochromatograms characteristics of Tc i Ru indicate a continuous migration of Ru and Tc oxides into lower temperature[2-4]. In the case of RuCl3 target, the additional formation of volatile Tc and Ru oxychlorides can not be excluded. Taking into account obtained results for isolation Tc from RuCl3 target, high-temperature part of temperature gradient was extended. Tc carrier-free radionuclides were trapped in scrubber with 6 Mol/l HCl. In these experimental conditions about 1% of total amount of Ru was catched in scrubber, too. The performed studies made it possible to obtain the following conditions for the separation Tc process: mass of RuCl3 target about 35 mg, starting temperature 1373 K, exposure time 100 minutes, O2 flow rate 60 cm3/min. In all experiments one peak of Rh was detected, probably as RhO2, at this same adsorption temperature independently of gradient temperature, exposure time and irradiated target material Ru or RuCl3 powder. The stable position of Rh peak during experiment indicates the possibility of separation Rh from target material. Further investigation is planned. Acknowledgement: The work was done within framework of Polish Governmental Strategic Project: Supporting technologies for the development of safe nuclear power, Action 4: Development of techniques and technologies supporting management of spent nuclear fuel and radioactive waste (No SP/J/4/143321/11). 1. M. Izumo, H. Matsuoka, T. Sowita, Y. Nagame, T. Sekine, K. Hata, S. Baba „ Production of 95mTc with Proton Bombardment of 95Mo” Applied Radiation and Isotopes 42 (1991) 297 2. A. Steffen, K. Bachmann, "Gas chromatographic study of volatile oxides and hydroxides of Re, Tc, Os, Ru and Ir - I Investigation by isothermal gas chromatography", Talanta, 25, 1978, 551 3. A. Steffen, K. Bachmann, "Gas chromatographic study of volatile oxides and hydroxides of Re, Tc, Os, Ru and Ir - II Thermochromatographic investigations", Talanta, 25, 1978, 677 4. B. Eichler, F. Zude, W. Fan, N. Trautman, G. Herrmann, "Volatilization and deposition of ruthenium oxides in a temperature gradient tube", Radiochimica Acta, 56, 1992, 133
Speakers: Mr Bogdan WĄs (The Henryk Niewodniczański Institute of Nuclear Physics Polish Academy of Sciences, Cracow, Poland), Dr Ryszard Misiak (The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences, Cracow, Poland)
• Concert Marble Hall

### Marble Hall

#### Casino Conference Centre

Reitenbergerova 4/95, Mari&#225;nsk&#233; L&#225;zn&#283;, Czech Republic <font color=white>
• Tuesday, May 13
• Chemistry of Actinide and Trans-actinide Elements 2 Red Hall

### Red Hall

#### Casino Conference Centre

Reitenbergerova 4/95, Mari&#225;nsk&#233; L&#225;zn&#283;, Czech Republic <font color=white>
Conveners: Prof. Andreas Türler (Paul Scherrer Institute and Bern University), Prof. Igor Izosimov (JINR)
• 103
Gas chromatography of element 113
The discovery of new superheavy elements with Z = 113-118 in 48Ca induced nuclear reactions was one of the most outstanding scientific achievement of the last decade. The long halflives of radionuclides of these elements extend the application of radiochemical techniques to their chemical characterization and to test the hypothesis about the impact of so-called "relativistic effects" on the chemical properties of superheavy elements [1]. According to Periodic Table element 113 belongs to group 13and its ground state electronic structure is [Rn]5f146d107s27p1 (i.e. homolog of Tl). Modern relativistic calculations predict weak adsorption on inert surfaces due to strong contraction and stabilization of surface 7 p1/2 orbital(adsorption enthalpy on Teflon is 14 kJ/mol, and on polyethylene 16 kJ/mol) [2]. At the same time due to relativistic stabilization 7p1/2 and high spin-orbital splitting of 7p element 113 has to easily be adsorbed (in H2/He) on Au surface (adsorption enthalpy is - 158.6 kJ/mol) [1]. Taking this into consideration we studied a gas chromatography of the given upwards theoretical predictions of element 113 properties, its adsorption of element 113 on a Au surface was studied compared to Hg and At (similar as in the case of Cn and Fl [3, 4]). The reaction 48Ca + 243Am was used to produce nuclides 288115 and its daughter 284113 [5]. Nuclear reaction products were stopped in a He / Ar gas mixture and atoms of volatile elements were transported by the gas jet through a Teflon capillary to chromatography column. Gas chromatographic column is a two-detector system consisting of Si detectors covered with gold. First detector operated at room temperature (20°C) and the second one with a temperature gradient from +20° C to -60 ° C. A total of five chains of 284113 was detected in the first isothermal detector. Adsorption enthalpy of element 113 on gold surfaces is comparable with that of mercury, which indicates that element 113 is a volatile metal and weakly interacts with inert surfaces. The probabilities for a random origin are 7.6x10e-3, 6.6x10e-5, 2x10e-4, 6.7x10e-10, 5.7x10e-6 calculated using Poisson distribution [6].Direct formation of nuclide 284113 in irradiation of 243Am with 48Ca in multi-nucleon transfer reactions (18 protons and 23 neutrons) is virtually impossible. From this we can deduce that isotopes of 113-111-109-107-105 elements detected in the experiment are daughters of mother nuclide 288115 synthesized in a reaction 243Am(48Ca,3n). The work was supported by Russian Foundation for Fundamental Research (project code 13-03-12205 ofi-m). REFERENCES 1.A. A. Rusakov, Yu. A. Demidov, A. Zaitsevskii, C.E.J Phys, 2013, 11, 1537 2.V. Pershina, A. Borschevsky, E. Eliav, U. Kaldor, J.Phys.Chem.A, 2008, 13712 3.R. Eichler N.V. Aksenov, Yu.V.Albinet al, Radiochim.Acta.,2010,98,133 4.R. Eichler, N.V. Aksenov et al, Nature, 2007, 447, 72 5.Yu.Ts.Oganessian, V.K.Utyonkov, Yu.V.Lobanov et al, PHYS. REV. C, 2004, 69, 021601 6.V. Zlokazov, Eur. Phys. J. A, , Eur. Phys. J. A, 2000, 8, 81–86
Speaker: Dr Gospodin Bozhikov (Jlint Institute for Nuclear Research)
• 104
Adsorption behavior of super-heavy elements (Z ≥ 112) on metal and inert surfaces
Investigation of chemical and physical properties of the heaviest elements (those beyond Lr) is a hot topic since several decades. In this time period, many new elements were discovered and after a proper characterization were added to the Periodic Table of the elements. The main problem of such investigations, however, is the rather short half-life of these elements, which requires the development of innovative experimental techniques. Nowadays the research focusses on the chemical properties of the element 114. So far, two gas chromatography experiments to study the interaction strength of element 114 with a gold surface have been performed with conflicting results. One experiment [1] reported a weak interaction of element 114 with a gold surface, leading to adsorption only at very low temperatures of approximately -90°C, while in the second experiment [2] adsorption on gold has been observed at the room temperature, indicating a much stronger bond between element 114 and gold. To resolve this conflict, further experiments on chemical properties of the element 114 will be performed at GSI and PSI/JINR in the next two years. For theoretical studies, standard quantum-mechanical packages that treat a system mostly non- or only scalar-relativistically are not satisfactory: Due to rather significant relativistic effects on the electron shells of the heaviest elements a fully-relativistic four-component description is required. Recently, we have studied the adsorption behavior of elements 112, Cn, and 114 and their lighter homologues Hg and Pb, respectively, on gold surfaces [3] by using a cluster-approach [4]. We found that Hg/Cn and Pb/114 prefer different adsorption sites. Also, the adsorption energies of elements 112 and 114 are related to those of their lighter homologues in a different way. Thus, Eb(Cn) is only slightly (0.1-0.2 eV) lower than Eb(Hg), while Eb(114) is much lower (1.4 eV) than Eb(Pb). This is due to the fact, that in element 112 both the relativistically stabilized 7s and destabilized 6d AOs take part in the binding, while for element 114 binding is mostly determined by the relativistically stabilized 7p1/2 orbital. In contrast to Pb, where 6p3/2 strongly contributes to the surface bond, the 7p3/2 participate much less due to its large relativistic destabilization (the spin-orbit splitting between 7p1/2 and 7p372 is about 3.5 eV). Furthermore, binding of element 114 to gold is similar to that of Cn, however, about 0.2 eV stronger. Our predicted sequence in the Eb values is Cn < Hg < E114 << Pb. Thus, we predicted that in the thermochromatography experiments, element 114 will adsorb right at the beginning of the chromatography column with the hot end of 35°C, at the position of Hg. This prediction was recently confirmed experimentally [2]. In this talk we will present theoretical results on adsorption energies and distances of the elements from 112 to 114 and their homologues on metal (gold) and inert (SiO2) surfaces. Acknowledgment: J.A. gratefully acknowledges the support by the Deutsche Forschungsgemeinschaft (DFG) and BMBF. References [1] R. Eichler et al. Radiochim. Acta, 98, 133 (2010). [2] A. Yakushev, NUSTAR-SHE-11, GSI Scientic Report 2009. [3] V. Pershina, J. Anton, and T. Jacob, J.Chem. Phys., 131, 084713 (2009). [4] J. Anton, B. Fricke, E. Engel, Phys. Rev. A69, 012505 (2004).
Speaker: Dr Josef Anton (University of Ulm)
• 105
Higher oxides, peroxides, and superoxides of early transuranium elements: a relativistic density functional study
The results of relativistic electronic structure calculations on simple molecules of higher oxides (actinide oxidation state VI through VIII), peroxides, and superoxides of Pu, Am, and Cm are reported. The calculations employed accurate “small-core” two-component pseudopotentials derived from the outer (valence) shell solutions of the atomic Dirac–Fock–Breit equations with the Fermi nuclear model; the optimal description of the valence (rather than semicore) shells appears essential for reproducing the chemical properties. The molecular semicore/valence many-electron problem was solved by the two-component non-collinear relativistic DFT technique with the fully unrestricted optimization of Kohn–Sham one-electron spinors expanded in weakly contracted Gaussian basis sets; the bases were optimized for spin-orbit-coupled calculations. Ground-state equilibrium structures, vibrational frequencies and charge and spin magnetization density distributions were analyzed in order to characterize the different isomers in chemical terms. The stability of higher oxidation states in oxygen compounds rapidly decreases from Pu to Am and further to Cm. All “true” An tetroxides (An = Pu, Am, Cm), were predicted to be thermodynamically unstable in realistic gas-phase conditions with respect to the decay into lower oxides (An2O6 or An2O7) and molecular oxygen as well as to the conversion into dioxosuperoxides [AnO2](O2) which appear to be the most stable An·4O species in all cases. Structural and magnetization-density features of the tetroxides indicate that Pu and Am are octavalent while Cm is only hexavalent. No structural similarities between higher oxides of Pu-Am and Os-Ir was found. A variety of bis-dioxygen species of different nature (An(O2)2, [AnO2](O2)2) is discussed. The stability of some heterooxide molecules (PuAmO6 and especially PuAmO7) with respect to the transformation to the mixture of the corresponding pure oxides is noticed. Implications for the chemistry of the transuranium element – oxygen systems and the identification of volatile An-oxygen compounds are discussed. The work is partially supported by the RFBR (grant # 13-03-01234). Thanks are due to Prof. C. van Wüllen for providing us with his relativistic DFT code. The calculations were performed at MCC NRC “Kurchatov Institute” (http://computing.kiae.ru/).
Speaker: W. H. Eugen Schwarz (Department of Chemistry, Tsinghua University, Beijing / Theoretical Chemistry, University Siegen)
• 106
Complexation And Extraction Studies Of High Valency Actinides By Salicylideneimine-based Ligands
Increased knowledge of actinide coordination chemistry and the development of advanced actinide separation processes are essential to reducing the radiotoxicity of used nuclear fuel. Commercial separation techniques for nuclear fuel (i.e. PUREX) selectively remove U(VI) and Pu(IV) from the other components, while the minor actinides, e.g. Np and Am, are not extracted. However, these four mid-actinides (U, Np, Pu, Am) all have highly accessible oxidation states (+V, +VI) at which they exist as linear dioxo actinyl ions [AnO2]n+. The An=O bonds are incredibly stable, permitting ligand coordination in the equatorial plane of the metal ion center and affording a geometry for unique bonding characteristics. Tetradentate Schiff bases can be prepared with synthetic ease and have been used extensively in the area of metal ion coordination chemistry. These ligands have rather planar structures that chelate around the equatorial plane of actinyl ions through their N(2)O(2) binding site, presenting the possibility that this distinct coordination environment may facilitate the selective solvent extraction or aqueous retention of pentavalent and hexavalent actinides. We have synthesized multiple organic and water soluble Schiff base ligands, of the salen and salophen type, and have conducted complexation and solvent extraction experiments with UO22+ and NpO2+, as representative actinyl ions. Preliminary results indicate that salen-based ligands show promise for extracting uranium from nitrate media, while a water soluble salen and a lipophilic di-t-butyl-salophen are the most promising in providing crystallized structures with UO22+ and NpO2+. Ongoing studies of these ligands in our laboratories will help to further define possible methods for used nuclear fuel separations.
Speaker: Mr Christian Bustillos (University of California Irvine Department of Chemical Engineering)
• 107
On the origin of selectivity of bis-triazinyl bipyridine ligands for complexation of americium(III) over lanthanides. Quantum mechanical analysis of M–N bonds
Selective separation of actinide elements from highly radioactive nuclear waste is the key issue for modern technologies of nuclear waste reprocessing. Partitioning of long-lived minor actinides, in particular americium, followed by their transmutation into short-lived and stable nuclides would lead to a significant reduction of long-term environmental hazard from this radiotoxic waste, and contribute to the development of safe nuclear power. Derivatives of 6,6’-bis([1,2,4]-triazin-3-yl)-2,2’-bipyridine (BTBP), the tetra-N-dentate lipophilic ligands which selectively extract trivalent actinides (An) over lanthanide fission products (Ln) from nitric acid solutions (modeling PUREX raffinate) to organic solvents (SANEX process), have been considered the most promising species for partitioning the minor actinides from high-level nuclear waste. Recent theoretical studies, carried out on two pairs of americium and europium complexes formed by the BTBP ligands, neutral [ML(NO3)3] and cationic [ML2]3+ where M = AmIII or EuIII, and L = 6,6’-bis-(5,6-diethyl-1,2,4-triazin-3-yl)-2,2’-bipyridine (C2-BTBP) [J. Narbutt, W.P. Oziminski, Dalton Trans. 41, 14416 (2012)], have shown that greater thermodynamic stability (in water) of the Am-L complexes than that of the analogous Eu species, caused by greater covalencies of the Am–N than Eu–N bonds, is the main reason of BTBP selectivity in the separation of these metal ions. Theoretical analysis of Am–N and Eu–N bonds in the BTBP complexes was carried out in this work, with the use of one-component Zeroth Order Regular Approximation (ZORA) Hamiltonian and Kohn-Sham density functional theory. Kohn-Sham orbitals were analyzed with Natural Population Analysis (NPA), Mulliken Population Analysis, Second Order Perturbation Theory (SOPT) implemented for Natural Bond Orbitals (NBO) and Symetrized Fragments Orbitals (SFO) with overlap populations density-of-states (OPDOS). Electron density was analyzed with The Quantum Theory of Atoms in Molecules (QTAIM). The QTAIM analysis for the bond critical points (BCP) confirms mostly ionic character of M-N bonds with slightly bigger covalent contribution for the Am-N than Eu-N bonds. This is due to a bigger charge transfer from the ligand to the Am than Eu ion, in particular to the 6d(Am) and 5d(Eu) orbitals. The results of the SOPT method show that the greater shift of electron density on the 6d(Am) orbitals is due to the large overlap integrals of 6d(Am) with the ligand donor orbitals, not to the smaller energy gap. This is in line with the calculated greater radial expansion of the 6d(Am) than 5d(Eu). The OPDOS coupled with the SFOs has shown that outermost occupied MOs as well as inner MOs are involved in the M-N interactions. This work was financed from the National Centre for Research and Development through the Strategic Program Technologies Supporting Development of Safe Nuclear Power Engineering, task 4: Development of spent nuclear fuel and radioactive waste management techniques and technologies.
Speaker: Prof. Jerzy Narbutt (Institute of Nuclear Chemistry and Technology)
• Chemistry of Nuclear Fuel Cycle 2 Mirror Hall

### Mirror Hall

#### Casino Conference Centre

Reitenbergerova 4/95, Mari&#225;nsk&#233; L&#225;zn&#283;, Czech Republic <font color=white>

(1st ASGARD International Workshop)

Conveners: Dr Katja Schmeide (Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology), Nicholas Evans (Loughborough University)
• 108
Humic colloid-associated migration of trivalent radionuclides in an argillaceous formation
Humic colloid-associated migration of trivalent radionuclides in an argillaceous formation C.BRUGGEMAN1*, N.MAES1, J.GOVAERTS1, S.SALAH1, L.WANG1, M.VAN GOMPEL1, S.BRASSINNES2 1Environment, Health and Safety Institute (EHS), SCK•CEN, Boeretang 200, B-2400 Mol, Belgium (*correspondence: cbruggem@sckcen.be) 2ONDRAF/NIRAS, Kunstlaan 14, 1210 Brussel, Belgium (s.brassinnes@nirond.be) It is generally accepted that natural humic colloids in the argillaceous Boom Clay formation (Belgium) modify the speciation and transport characteristics of several long-lived radionuclides [1]. However, universal formalisms to describe the complex suite of processes and mechanisms in such environment were lacking, resulting in "operationally defined migration parameters" [2] that did not allow significant confidence building with regard to safety assessments. In this paper we present a comprehensive overview of the latest achievements that have been obtained in the understanding, interpretation and description of trivalent radionuclide retention and migration in the Boom Clay. Using a classical bottom-up approach, a geochemical modelling concept relying on thermodynamic sorption models (TSMs) is presented. With this approach, we have succeeded in describing adsorption of Eu(III) and Am(III) in batch suspensions of increasing complexity, from relatively straightforward mixtures of illite and dissolved organic matter (DOM) [3], to Boom Clay suspensions. The results of these adsorption experiments demonstrate that trivalent radionuclides are strongly bound to the solid phases present in Boom Clay, but that their solid-liquid distribution is heavily influenced by DOM. Hereafter we discuss results from short-term and long-running (>10 years) column migration experiments with Am(III) on Boom Clay cores. These experiments clearly indicate the existence of a kinetically-controlled colloidal transport pathway that determines the flux of Am(III) through the clay core. A modified kinetic colloid transport model has been developed [4], based partly on the aforementioned adsorption models, that allows for the quantitative description of all experimental data obtained thus far. In this model, it is considered that the radionuclide is predominantly transported as an organic matter complex/colloid that slowly dissociates, and both the colloid as well as the dissolved radionuclide ions are capable of sorbing to the solid phase. The role of humic colloids as a transport vector is thoroughly discussed and evaluated within the larger framework of geological disposal of radioactive wastes. [1] Henrion et al. (1985) Eng. Geol. 21, 311-319 [2] SAFIR 2 – Safety Assessment and Feasibility Interim Report 2 (2001) NIROND 2001-06 E, Brussels, Belgium [3] Bruggeman et al. (2010) Radiochim. Act. 98, 597-605 [4] Maes et al. (2011) Phys. Chem. Earth 36, 1590-1599
Speaker: Dr Christophe Bruggeman (Belgian Nuclear Research Centre SCK•CEN)
• 109
Cesium uptake by Ca/Mg bentonite: evaluation of sorpion experiments by a multicomponent two-site ion-exchange model
Understanding the migration processes in the near-field of the geological disposal of nuclear wastes at the basic level can help to develop models, which may be used in transport codes that can predict the migration of radioactive contaminants in the field scale. Cesium is well adsorbed by clay minerals and many studies concerning adsorption of cesium on different types of clay minerals have been published so far. As in the Czech project of deep underground repository the application of local bentonite is proposed, in this work, cesium adsorption on Czech Ca/Mg bentonite (Rokle deposit, NW Bohemia) has been studied. In our previous study two main differences between Rokle bentonite and worldwide studied Na-bentonites were observed: (1) the great influence of phase ratio m/V on the shape of Cs sorption isotherm in the range of higher Cs concentration, and (2) a substantial content of micas and mica-type clay minerals (about 19 wt. %) that are believed to cause the specific Cs sorption in the lower concentration range due to the presence of the Frayed Edge Sites (FES). In this work, cesium sorption on Ca/Mg-bentonite of the Czech origin was studied using batch technique for wide ranges of both bentonite-to-water ratio (m/V) and initial concentration of CsCl (10(-7) – 0.1 mol/l), isotope Cs-137 was used as a tracer. The total cation-exchange capacity of the bentonite was 0.50 equiv/kg. The experiments revealed non-linear character of cesium sorption, substantially influenced by the m/V. The numerical evaluation of batch experiments performed with the use of PHREEQC, in which exchange reactions between added Cs+ and Mg2+, Ca2+, Na+ and K+ ions sorbed initially on the bentonite were taken into account, enabled to determine selectivity coefficients of all mentioned cations, according to the Gaines-Thomas convention. The model describing exchange reactions mentioned was successfully verified on a broader set of experimental data that was previously interpreted by a simple ion-exchange model taking into account the exchange of cesium with an unspecified divalent cation. The shape of equilibrium isotherms indicated for initial concentrations of cesium smaller than 0.001 mol/l the possibility to describe the cesium uptake on Ca/Mg-bentonite by a two site model. Using this assumption, capacity of the second type of sites with higher selectivity to cesium, was calculated as about 0.01 equiv/kg. This specific cesium sorption capacity, which is generally believed to be associated with the frayed edge sites (FES) of illitic materials, was also measured using AgTU method. The values resulting from both the methods were of the same order, differences were discussed. The first results of 1D transport modelling in the PHREEQC environment respecting the developed multicomponent ion-exchange model could help by the interpretation of results of diffusion transport of some cations in the layer of compacted bentonite.
Speaker: Dr Dušan Vopálka (Department of Nuclear Chemistry, Czech Technical University in Prague, Czech Republic)
• 110
Speciation of technetium after sorption and diffusion in Opalinus Clay
The long-lived radioactive isotope technetium-99 (99Tc, t1/2= 2.14•105 a) is a fission product of 235U and 239Pu and can be released to the environment from nuclear facilities, high-level radioactive waste repositories or as a result from nuclear weapon testing. Its geochemistry is dominated by the very mobile and soluble pertechnetate anion (TcO4-) under oxic, and a less mobile and less soluble TcO2•nH2O phase under anoxic conditions [1]. For the storage of high-level nuclear waste, argillaceous rocks are under investigation as potential host rocks for repositories in several European countries. Thus, detailed information about the interaction of Tc with these host rock formations is mandatory for the assessment of the long-term safety of high-level nuclear waste repositories. For our studies we selected Opalinus Clay (OPA) from Mont Terri, Switzerland, and its corresponding pore water. OPA is mainly composed of clay minerals (66 wt.%), quartz (14 wt.%), calcite (13 wt.%), siderite (3.0 wt.%), pyrite (1.1 wt.%), and organic carbon (0.8 wt.%) [2]. The sorption of 4-13 µM Tc(VII) on OPA powder was studied in batch experiments under aerobic and anaerobic conditions as a function of pH, clay concentration, and amount of dissolved Fe(II). Diffusion experiments were performed with intact OPA bore cores (20x10 mm and 25x11 mm) with diffusion parallel and perpendicular to the bedding. The experiments were performed under aerobic conditions with 7 µM TcO4- at neutral pH. Furthermore, different sorption samples on OPA thin sections (contact area 16 mm²) with 3-35 µM Tc(VII) were prepared under anaerobic conditions for spatially resolved, molecular-level investigations to determine the speciation of Tc on the mineral surface. The batch experiments showed that in the neutral pH range the sorption of Tc on OPA is very low, i.e. ≤ 1% under aerobic and 8% under anaerobic conditions. We also found that the sorption is independent of the clay concentration. Addition of dissolved Fe2+ increased the uptake of Tc by OPA up to 99%. The low sorption of Tc on OPA under aerobic conditions agrees well with our results from diffusion experiments, where Tc(VII) migrates quickly through an intact OPA bore core within about one week in case of diffusion parallel to the bedding. For diffusion perpendicular to the bedding, TcO4- migrates through the bore core within one month. µ-XRF mappings of the sorption samples showed a homogeneous distribution of Tc on the OPA surface with some local enrichments. In these spots the dominant oxidation state of Tc was found to be tetravalent as determined by Tc K-edge µ-XANES measurements. Our results indicate that OPA is able to reduce at least part of TcO4- to a less mobile and less soluble Tc(IV) species and thus may retard the migration of Tc from the repository to the environment. This work was financed by BMWi under contract no. 02E10981. The authors thank Diamond Light Source for access to beamline I18 (Proposal 8725) that contributed to the results presented here and Prof. Mosselmans for his support during the experiment. The research leading to these results has received funding from the European Community’s Seventh Framework Programme (FP7/2007-2013) under grant agreement nº 226716. References: [1] K. Lieser; Ch. Bauscher, Radiochim. Acta, 42, 1987,205 [2] NAGRA, Techn. Bericht NTB 02-03, NAGRA Wettingen/Schweiz, 2002
Speaker: Ms Maria Lübke (Institute of Nuclear Chemistry; Johannes Gutenberg University Mainz (Germany))
• 111
Ruprechtov natural analogue site: summary of the real system behaviour
Deep geological repositories (DGR) for the final disposal of spent nuclear fuel and high-level radioactive waste are primarily based on a multi-barrier concepts, consisting of a host rock as a natural geological barrier and an engineered barrier-system. Detailed investigations of suitable geological analogues may lead to a better understanding of the complex interrelations between transport and sorption of radionuclides in multi-barrier systems under natural conditions and especially on very long-term scales relevant for performance assessment. The Ruprechtov site (W Bohemia) was chosen as a natural analogue because the geological and geochemical conditions are similar to sedimentary sequences which in many cases cover the potential host rocks for DGR. The site selection supported also natural accumulations of U, which enabled to identify the main mobilisation/immobilisation processes. During the international research, which took place at Ruprechtov site since 1995, multidisciplinary investigations were performed, including detailed hydrogeological, geological, mineralogical and geochemical characterisation. Furthermore, the core part of the investigations were focused on natural U occurrences as analogue for U migration and immobilisation in the DGR post-operational phase. The Ruprechtov site represents a Tertiary basin with argillized volcano-detritic sediments, underlain by kaolin and granite. U-enrichments mainly occur in distinct layers of limited thickness on top of the kaolin close to the clay-lignite seams (Noseck et al., 2004). The combination of different analytical methods was applied to gain an insight into the behaviour of U in a complex natural system such as wet chemistry (distribution of U(IV) and U(VI), sequential extraction, 234U/238U-activity ratios determination) and various spectroscopic methods (SEM–EDX spectroscopy, synchrotron-based l-EXAFS, EMPA and confocal l-XRF). Noseck et al. (2008) presented the scenario for U enrichment: Microbial activity in the clay/lignite horizon led to the reduction of dissolved sulphate by sulphate-reducing bacteria, thereby leading to the formation of pyrite nodules. Noseck et al. (2008) also identified using determination of 234U/238U activity ratios that the accumulation process has to be at least older than 1 Ma year. In this period, CO2-rich water likely initiated U release from accessory minerals in the granite by formation of soluble uranyl-carbonate complexes. Uranium was transported into the clay/lignite horizon and accumulated there by reduction of U(VI) to U(IV) by thin As-pyrite layers on pyrite nodules formed by microbial sulphate reduction. Moreover, microbial degradation of organic matter in the clay/lignite horizon probably caused also phosphate release into the groundwater. The increased phosphate concentrations caused the precipitation of U as secondary phosphate minerals (e.g. ningyoite). The key processes involved in U immobilisation in the argillaceous layers have been identified and can be used to reconstruct the geological history at the site. The gained results were summarized in several publications (e.g. Noseck et al., 2008, 2009, 2012). Acknowledgment: This research was financially supported by Ministry of Trade and Industry of the Czech Republic (TIP FR-TI1/362 and Pokrok 1H-PK25), by SÚRAO, by the German Federal Ministry of Economics (BMWi) and by the Euratom FP7, Integrated Project FUNMIG. References: Noseck, U., Brasser, Th., Rajlich, P., Laciok, A., Hercík, M.: Radiochim. Acta. 2004; 92, 797–803. Noseck, U., Brasser, Th., Suksi, J., Havlová, V., Hercík, M., Denecke, M. A., Förster, H. J.: J. Phys. Chem. Earth. 2008; 33, 14-16, 969-977. Noseck, U., Rozanski, K., Dulinski, M., Havlová, V., Šráček, O., Brasser, Th., Hercík, M., Buckau, G.: Appl. Geochem. 2009; 24, 9, 1765-1776. Noseck, U., Tullborg, E-L., Suksi, J., Laaksohardu, M., Havlová, V., Denecke, M. A., Buckau, G.: Appl. Geochem. 2012; 27, 490-500.
Speaker: Radek Červinka (ÚJV Řež, a. s., Czech Republic)
• 10:00 AM
Coffee Break Marble Hall

### Marble Hall

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Reitenbergerova 4/95, Mari&#225;nsk&#233; L&#225;zn&#283;, Czech Republic <font color=white>

### Mirror Hall

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Reitenbergerova 4/95, Mari&#225;nsk&#233; L&#225;zn&#283;, Czech Republic <font color=white>

(session dedicated to the memory of prof. Petr Beneš)

Conveners: Prof. Pavel Povinec (Comenius University), Mrs Věra Bečková (National Radiation Protection Institute)
• 112
Memorial of Prof. Petr Beneš
Speakers: Prof. Amares Chatt (Dalhousie University), Prof. Christian Ekberg (Nuclear Chemistry, Chalmers), Prof. Jan John (CTU in Prague, FNSPE, Department of Nuclear Chemistry), Jan Kučera (CTU FNSPE, centrum pro radiochemii a radia?ní chemii)
• 113
Mobility of radiocaesium in boreal forest ecosystems: Influence of precipitation chemistry
Mobility of radiocaesium in boreal forest ecosystems: Influence of precipitation chemistry Steinnes E1, Gjelsvik R2, Skuterud L2, Thørring H2 1. Department of Chemistry, Norwegian University of Science and Technology, No-7491 Trondheim, Norway 2. Norwegian Radiation Protection Authority, NO-1332 Østerås, Norway Mobility and plant uptake of Cs in soils is generally limited by the presence of clay minerals in the soil. However, cations supplied by precipitation may substantially influence the mobility of radiocaesium in natural surface soil and subsequent transfer to food chains. The chemical composition of precipitation shows substantial variation among different areas in Norway for two main reasons. At sites close to the coast the atmospheric supply of marine cations and anions is many-fold greater than in regions shielded from marine influence by mountains. The southernmost part of the country has been, and still is, substantially affected by soil acidification due to long-range atmospheric transport of acidifying substances from areas elsewhere in Europe. This may explain a much higher greater uptake of 137Cs from the Chernobyl accident in moose in this region than elsewhere (Steinnes et al., 2009), in spite of the fact that some areas farther north received substantially greater fallout. Similarly a much greater transfer of 137Cs to natural birch forest vegetation is evident from the more acidified soils in the south than in comparable ecosystems elsewhere in the country (Thørring et al., 2012). Repeated recordings of activity levels in natural surface soils showed faster leaching of Chernobyl 137Cs relative to inland areas not only in the south but also in coastal areas farther north (Gjelsvik and Steinnes, 2013), indicating that the amounts of marine cations in precipitation also has an appreciable effect on the Cs leaching. The geographical leaching differences still became less prominent with time. Recent lysimeter experiments with undisturbed soil columns obtained from an area receiving high radiocaesium deposition from the Chernobyl accident, applying precipitation with ionic composition characteristic of the different regions mentioned above, did not change the current depth distribution of 137Cs. However, acidic precipitation increased the mobility of Cs added during the experiment. All in all the mobility in boreal soils of freshly added radiocaesium may be considerably affected by the chemical composition of precipitation. References Steinnes E, Gaare E, Engen S, 2009. Influence of soil acidification in southern Norway on the 137Cs exposure of moose? Sci. Total Environ. 407 (2009) 3905-3908. Thørring H, Skuterud L, Steinnes E, 2012. Distribution and turnover of 137Cs in birch forest ecosystems: influence of precipitation chemistry. J. Environ. Radioact. 110 (2012) 69-77.. Gjelsvik R, Steinnes E, 2013. Geographical trends in 137Cs fallout from the Chernobyl accident and leaching from natural surface soil in Norway. J. Environ. Radioact. 126 (2013) 99-108. Thørring H, Skuterud L, Steinnes E, 2014. Influence of chemical composition of precipitation on migration of radioactive caesium in natural soils. J. Environ. Radioact., submitted. Keywords: Radiocaesium, precipitation chemistry, soil, plants, moose
Speaker: Prof. Eiliv Steinnes (Norwegian University of Science and Technology)
• 114
Study of 137Cs, 241Am and Pu isotopes sorption behavior in the environment: Prague – Vilnius collaboration*
Results of long-term collaboration with the Czech Technical University in Prague are reported. Sorption behavior of 137Cs, 241Am and Pu isotopes was studied with the aim of better understanding their migration mechanisms in the Triassic clay selected for engineered barrier of the near surface low and intermediate level radioactive waste repository, as well in soil and bottom sediments from the natural environment. The Baltic Sea bottom sediments and well characterized clay samples with different amounts and compositions of iron oxides as well as synthetic magnetite, goethite and hematite were used in equilibrium and kinetic sorption experiments. Sorption was studied as a function of pH, a composition of solutions, and a contact time. The character of Cs, Pu and Am bonding was analyzed by sequential extraction (SE). Solvent extraction techniques, ultrafiltration and alpha spectrometry as well as ICP-MS were employed to characterize the oxidation states of the formed plutonium species. Two Chernobyl soil cores were also analyzed on the vertical distribution of radionuclides, their bonding to soil components, as well as on Pu oxidation state distribution. Experimental data obtained from the laboratory and field observations were used in modeling. Despite their similar sorption kinetics, Pu(IV), Pu(V) and Am(III) showed different bonding to soil, clay and bottom sediment coatings. Pu was predominantly associated with amorphous Fe-oxides and natural organic matter sites, whereas in the case of Am(III), the exchangeable and carbonate sites played the principal role. It has been shown that Pu(V) sorption mechanism includes a very fast Pu (V) reduction (reaction rate ≤ 2.33•10-3s-1) to Pu (IV) and partly to Pu(III). Following reduction Pu isotopes were bound to various components of bottom sediments via ion exchange and surface complexation reactions and a slow incorporation into the crystalline structure of Fe minerals. Kinetics experiments showed that the sorption of Cs(I), Pu(V), Pu(IV) and Am(III) to bottom sediments from natural seawater was controlled by the inert layer diffusion process. The analyses of data obtained from sorption experiments, field observations and speciation of radionuclides have indicated a slightly higher migration potential for Am both in the Chernobyl soil and the natural clay minerals. The exchangeable and carbonate bound Am(III) should display faster migration rate and greater bioavailability in the environment. *) Dedicated to the memory of Prof. Petr Beneš
Speaker: Dr Galina Lujaniene (SRI CENTER FOR PHYSICAL SCIENCES AND TECHNOLOGY)
• 115
Joint Bratislava-Prague AMS/IBA studies using tandem accelerator
P.P. Povinec1, I. Světlík2, J. John3, M. Ješkovský1, M. Němec3, J. Kučera2 1 Faculty of Mathematics, Physics and Informatics, Comenius University, Bratislava, Slovakia 2 Institute of Nuclear Physics, Czech Academy of Sciences, Řež near Prague, Czech Republic 3 Faculty of Nuclear and Physical Engineering, Czech Technical University, Prague, Czech Republic A joint research programme has been established to study anthropogenic radionuclides in the environment using Accelerator Mass Spectrometry (AMS), namely 14C variations in the atmosphere and biosphere, and content of plutonium isotopes in the atmosphere and hydrosphere. Specifically, observations of 14C variations in the atmosphere and biosphere around the Czech and Slovak nuclear power plants wil be presented and discussed in detail. Ion Beam Analysis (IBA) techniques have ben applied for radiation damage studies of construction materials of nuclear reactors, and of electronics components working in high radiation fields, e.g. at nuclear reactors and in space instruments. ___________________________ *) Dedicated to the memory of Prof. Petr Beneš
Speaker: Prof. Pavel Povinec (Comenius University)
• Separation Methods, Speciation 2 Red Hall

### Red Hall

#### Casino Conference Centre

Reitenbergerova 4/95, Mari&#225;nsk&#233; L&#225;zn&#283;, Czech Republic <font color=white>

(session dedicated to the memory of prof. Věra Jedináková-Křížová)

Conveners: Prof. Guozhong Wu (Shanghai Institute of Applied Physics, Chinese Academy of Sciences), Dr Ljudmila Benedik (Jožef Stefan Institute)
• 116
Actinide and Lanthanide Interactions with Engineered Mesoporous Materials
Ordered mesoporous materials are attractive sorbents due to their extremely high surface areas, large pore volumes, open frameworks, and highly-ordered, tunable structures. Ultimately, they could be used for separating actinide and lanthanide ions from assorted solution matrices, as well as from each other. Furthermore, functionalized mesoporous materials may be useful for a variety of nuclear and non-nuclear applications including the sequestration of radionuclides for proper long-term storage, environmental sequestration of heavy metals, and nuclear waste reprocessing. Processing of nuclear waste via liquid-liquid solvent extraction produces large amount of high-level liquid wastes that in turn hamper their permanent disposal. Replacing the organic radionuclide extractant solutions with functionalized mesoporous materials, that have the extraction ligands chemically bound to the mesoporous surface, will result in a significant volume reduction and reusability of the material. We are synthesizing non-functionalized and functionalized mesoporous silica and carbon materials to study their interaction with aqueous solutions of europium, neptunium, and plutonium over a wide pH range. This presentation will give an overview of the current status of this research field. I will discuss the characterization and effectiveness of the functionalization of mesoporous silica and carbon by a variety of analytical techniques (FTIR-ATR; PZC; SEM; 13C ssNMR and 29Si ssNMR; TEM; XRD; XAS), the uptake of radionuclides as a function of pH, and the kinetics and reversibility of these processes. Acknowledgement This research was sponsored in part by the National Nuclear Security Administration under the Stewardship Science Academic Alliances program under Award Number DE-NA0001978.
Speaker: Prof. Heino Nitsche (UC Berkeley and Lawrence Berkeley National Laboratory)
• 117
Investigations of water-soluble salicylaldimine-based ligands for the separation of actinyl and non-actinyl cations
Current systems for the separation of actinide and lanthanide cations often employ organophosphorus reagents in combination or in sequence with anionic extractants under acidic conditions. Organophosphorous reagents do not often display large selectivity between trivalent actinides and lanthanides, as a consequence of the similar chemical properties of these elements and may require addition of soft donor ligands. Several of the actinides have higher oxidations states (e.g., V and VI) available under conditions in which they exist as linear dioxo cations. Under this configuration the actinides behave significantly different from trivalent lanthanides. The stability of these oxidation states can be a challenge for some transuranic actinides under acidic conditions. Studies suggest, however, that these oxidation states may be stabilized by coordination of ligands to the equatorial plane of the actinyl ion. For example, recent studies indicate that Schiff bases have been able to stabilize U(V). In light of these reports we are investigating ligands for the selective complexation of An(V/VI)-cations. Possible improvements in Ln/An separation factors may afford the design of separation systems under conditions not commonly considered for nuclear fuel and waste effluent processing. In this paper we present results for the extraction of lanthanide(III) and actinyl(VI) cations from aqueous buffered solutions containing the water-soluble Schiff base N,N'-bis(5-sulfo-salicylidene)ethylenediamine (H2SalenSO3) by bis(2-ethylhexyl)phosphoric acid (HDEHP) in a suitable solvent. The effects of pH, buffer composition, and aqueous complex formation on the partitioning of metal ions are examined in terms of the ability of the aqueous ligand to retain actinyl ions while extracting non-actinyl ions. Spectroscopic and potentiometric titrations of H2SalenSO3 with UO22+ and NaOH have yielded valuable data, including conditional formation constants and ligand pKa values. Both spectroscopic data and the crystal structure of the complex with UO22+ confirm that it has a 1:1 stoichiometry. Notably, visible spectroscopic measurements of solutions of the ligand with Nd(III) indicate that interactions between H2SalenSO3 and Ln(III) are quite weak. Combined with investigations of the effect of ligand hydrolysis on the formation of metal ion complex(es), the results indicate that optimum conditions for complexation occur at acidities lower than those typically maintained in f-element extraction by HDEHP. Therefore, competitive extraction studies have been carried-out at p[H] values between 5 and 6. Continuous contact experiments for U(VI) extraction by HDEHP in toluene in the presence and absence of H2SalenSO3 demonstrate that the uranyl ion distribution ratios (D) are less than 2 and holdback factors are substantial (D0/D ≈ 100 to 800). Because both distribution ratios and holdback factors for Ln(III) extraction under similar conditions remain in the single digits, it is thought that the extent of aqueous ligand hydrolysis and the low acidity present challenges to maintaining extractable species. Investigations of the factors that lead to poor extraction of Ln(III) ions and the evaluation of similar, but more hydrolytically stable ligands, are ongoing.
Speaker: Dr Cory Hawkins (University of California, Irvine)
• 118
Simultaneous extraction of radionuclides with crown ethers and N,N,N’,N’-tetraalkyl diglycolamides mixtures in fluorinated diluents
Simultaneous recovery of long living radionuclides (cesium, strontium and actinides) from high level liquid waste (HLLW) allows to reduce the total volume of the waste and the costs of waste storage. The UNEX process using solvent based on chlorinated cobalt dicarbollide (CCD), polyethylene glycol and phenyloctyl-N,N-diisobutylcarbamoylmethylene phosphine oxide (CMPO) has been proposed for simultaneous recovery of the radionuclides. The main drawback of UNEX process is complicated synthesis of CCD. So development of new solvents and processes on the base of commercially available extractants is an important task. N,N,N’,N’-tetraalkyl diglycolamides (DGA), well-known ligands for actinides extraction, can also be used for strontium recovery from nitric acid solutions. At the same time the solutions of crown ethers in fluorinated diluents extract cesium from acidic solutions. Thus the mixture of DGA and crown ether is a promising solvent for simultaneous recovery of long living radionuclides from HLLW. In radiochemical technology saturated hydrocarbons are traditionally used as diluents for neutral ligands. For instance n-dodecane is traditionally used as a diluent for DGA. The main drawback of such diluent is low loading capacity on extracted metals and as a result tendency of third phase formation at high metal concentrations. The usage of fluorinated diluents such as meta-nitrobenzotrifluoride (F-3) allow to increase the loading capacity of the extractant and prevent third phase formation. It is also known that the most effective diluents for crown ethers are fluorinated alcohols. The goal of this work was to develop a new solvent on the base of crown ether and DGA for simultaneous extraction of actinides, lanthanides and fission products. The extraction of cesium, strontium, americium and lanthanides with different DGA (N,N,N’,N’-tetrabutyl diglycolamide, N,N,N’,N’-tetrahexil diglycolamide, N,N,N’,N’-tetraoctyl diglycolamide), crown ethers and their mixtures was studied. The solution of di-benzo-21-crown-7 and N,N,N’,N’-tetraoctyl diglycolamide in fluorinated diluent was chosen as a new solvent. The extraction flowsheet was developed and tested in laboratory scale using simulated solutions with high concentration of lanthanides. Optimum conditions for simultaneous recovery of cesium, strontium and actinides from nitric acid solutions, scrubbing and stripping were found.
Speaker: Ms Lyudmila Tkachenko (Khlopin Radium Institute)
• 119
Recovery of actinides and lanthanides on solid-phase extractants from nitric acid solution
Recovery of trivalent actinide and rare earth elements from complicated nitric acid solutions is important and difficult task of radiochemistry. Sorption materials for radionuclide recovery must possess the high sorption efficiency, selectivity of recovery, chemical stability and good kinetic properties. Solid-phase extractants (SPEs) prepared by impregnation of solid supports with ligands are the most appropriate for this purpose. Compounds for impregnation provide formation of complexes with actinides and lanthanides in nitric acid solution and ensure the possibility of their recovery. New types of solid supports for impregnation – high-porous and fine-dispersive polymers and carbon nanomaterials – are very promising for the SPE preparation. These materials ensure strong retention of impregnated ligands, efficiency and stability of SPEs in solutions with high content of nitric acid as well as good kinetic and other properties. This report is focused on sorption ability and efficiency of application of novel SPEs developed by us for recovery of actinide and lanthanide from nitric acid solution. As solid supports we have used Taunit carbon nanomaterial (NanoTech-Center, Russia) and polystyrene polymers – high crosslinked (Isolute, Sweden) or hyper cross-linked (Macronet, UK). For impregnation the phosphorus and nitrogen containing ligands have been used: diphenyldibutylcarbamoylmethylphosphine oxide, tetraoctyldiglycolamide, tri-n-octylphosphine oxide, di-2-ethylhexylmethylphosphonate; these ligands possess of the high efficiency in nitric acid solution also applied in liquid-liquid extraction processes. Impregnation was carried out by solutions of ligands in organic solvents (dichloroethane) or by ligands in nitric acid solution. Impregnation in nitric acid is more advanced technique because it provides high stability of SPEs and efficiency of their application in solution with high content of nitric acid. Novel SPEs have demonstrated high sorption ability toward actinides and lanthanides (distribution coefficients in 3 mol/L HNO3 are 10^3-10^4 mL/g, good kinetic properties and high efficiency of recovery in batch or column mode. On the base of experimental data we have developed the regimes of sorption preconcentration of actinide and lanthanide elements from 1-3 mL 3 mol/L HNO3 and determined conditions of their elution. The selectivity of actinide and lanthanide recovery is conditioned by properties of impregnated ligand and conditions of experiment. In this report we demonstrate examples of selective recovery of trivalent lanthanides with their separation from uranium and thorium. For this purpose we have used solid-phase extractants obtained by impregnation of various types of ligands. By use of multicomponent model solution, the effect of several elements that can be present in solutions of spent fuel reprocessing in nitric acid was examined. Reference: E.A. Zakharchenko, D.A. Malikov, N.P. Molochnikova, G.V. Myasoedova, and Yu.M. Kulyako. Sorption Recovery of U(VI), Pu(IV), and Am(III) from Nitric Acid Solutions with Solid-Phase Extractants Based on Taunit Carbon Nanotubes and Polystyrene Supports. Radiochemistry, 2014, Vol. 56, No. 1, pp. 27–31 Ascnowlegement: The work was supported by Program no.9 of the Presidium of the Russian Academy of Sciences: Development and Improvement of Methods for Chemical Analysis and Structural Study of Substances and Materials
Speaker: Ms Elena Zakharchenko (V.I.Vernadsky Institute of Geochemistry and Analytical Chemistry, Moscow, Russia)
• 120
Pyrochemical Extraction Analysis of an Immiscible Molten LiCl-KCl/Cd System
Immiscible liquid contacting is one the most common and important phenomena in the high temperature pyrochemical systems. Among these processes, an extraction system employing molten LiCl-KCl and liquid Cd metal has been proposed for the pyrochemical recovery of actinides in a waste salt treatment step. Understanding the complex interaction of immiscible fluid dynamics with mass transfer is a fundamental importance in a liquid-liquid extraction process. The use of a liquid cadmium electrode, which is the unique features of the process, provides hydro-dynamically a free surface contacting with an immiscible molten-salt electrolyte. This free interface of immiscible liquids gives an interface for mass transfer and is inconstant depending on agitated conditions. A computational method to expect an effective area for the mass transfer in the molten-salt and liquid metal system is particularly interesting and challenging for an agitated operation frequently encountered in the pyrochemical system. Details of the calculation of the velocity fields and free surface profiles which evolve in time are given. Representative simulation results are presented to illustrate the capabilities of this method for the molten LiCl-KCl/Cd system. In addition, this study also presents a new modeling approach for studying an analysis of a counter current multistage extraction in the immiscible molten streams. An operational analysis of a counter current multistage extraction was carried out by the model equations, composed of species material balance and distribution relationships between molten salt and cadmium phase. The solutions were determined by using the matrix-based numerical method and the parametric investigations were simulated for the effect of the operating variables on the decontamination factor. The decontamination performance and species concentration profiles could be obtained by considering the flow ratio of immiscible liquids and oxidant feed throughout the multistage extraction step in a given actinides concentration condition of the waste stream.
Speaker: Dr K.R. Kim (Korea Atomic Energy Research Institute)
• 121
Direct Dissolution and Electrochemical Studies of f-elements in Ionic Liquid
The unique and tunable properties of the second generation moisture-stable ionic liquids (ILs) have generated interest in their applications to the nuclear fuel cycle. Generally, ILs have low vapor pressure, chemical and radiation stability, good conductivity, and importantly, wide electrochemical windows. This beneficial electrochemical property allows for the ability to reach the negative potentials that are required for the reduction of lanthanides and actinides to metal species. Reduction of actinides and lanthanides to the metal has been largely unavailable in aqueous systems without the aid of mercury electrodes. Ionic liquids could therefore be envisioned as a system into which the used fuel once dissolved could be used to recover the uranium and separate other fission products by applying different potentials. However, the solubility of f-elements in ILs has not been extensively explored. Therefore, a more fundamental understanding of f-element chemistry and electrochemistry in ionic liquids is necessary to evaluate the system. Exploring methods to enhance and control f-element solubility in ILs is presented. In addition, investigation of the conditions for electrodeposition of uranium from the IL and analysis of the deposited species were conducted. A direct dissolution method which uses the protic form of the anion common to an ionic liquid can provide a pathway for increased solubility of f-elements in ILs. The inclusion of water also enhances the direct dissolution process within the IL. The direct dissolution of lanthanide carbonates and uranium carbonate has been achieved in the IL trimethyl-n-butylammonium bis(trifluoromethanesulfonyl)imide ([Me3NnBu][TFSI]) using the acid bis(trifluoromethanesulfonyl)amide (HTFSI). In addition to the carbonates, direct dissolution of U3O8 was performed. Analysis included UV-Visible and IR spectroscopy to characterize the soluble species and investigate possible complexation with the TFSI ligand. Cyclic voltammetry has been performed at common working electrodes such as Pt, Au, and glassy carbon (GC) to investigate the pathway from the soluble species to reduction. Potential mediated deposition of species from the [Me3NnBu][TFSI] has been achieved and analysis of the deposits was conducted using scanning electron microscopy (SEM) and energy dispersive x-ray emission spectroscopy (EDX). The results indicate that while deposition from the IL is possible despite residual water, the resulting deposited species tend to be oxides. Further studies on electrochemical parameters and utilizing simple methods to remove water are being investigated in an attempt to promote deposition to the metal from IL solutions.
Speaker: Janelle Droessler (University of Nevada, Las Vegas)
• 12:15 PM
Lunch Marble Hall

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Reitenbergerova 4/95, Mari&#225;nsk&#233; L&#225;zn&#283;, Czech Republic <font color=white>
• Chemistry of Actinide and Trans-actinide Elements 3 Mirror Hall

### Mirror Hall

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Reitenbergerova 4/95, Mari&#225;nsk&#233; L&#225;zn&#283;, Czech Republic <font color=white>
Conveners: Prof. Jerzy Narbutt (Institute of Nuclear Chemistry and Technology), Dr Ladislav Havela (Charles University)
• 122
Utilization of Technetium and Actinide Compound Synthesis and Coordination Chemistry for the Nuclear Fuel Cycle: Exploring Separations, Fuels, and Waste Forms
Compared to other elements on the periodic table, technetium and the actinides are less explored, especially in areas of compound synthesis and coordination chemistry. The nuclear fuel cycle offers opportunities to investigate fundamental and applied technetium and actinide chemistry in more detail, with fundamental complexation chemistry providing insight into waste forms, fuels, and separations. Examples are given for technetium and actinide solution and solid phases, with the coordination chemistry explored by spectroscopy and diffraction. An overview on technetium waste forms is provided, highlighting the need for fundamental information on this element to improved synthetic routes and understand resulting behavior. The thermal and hydrothemal based synthesis of technetium compounds is described. Spectroscopic and diffraction results are provided. Trends in the products from computation [1] and experiment are discussed, emphasizing the role of technetium-technetium interaction with oxidation state change. For waste forms, low valent or metallic phase formation demonstrates enhanced inter-technetium interactions which grants the resulting compounds resistance to corrosion or limits solubility. Development of advanced fuels can leverage innovative synthetic techniques that are utilized in the laboratory and non-nuclear industry. In particular methods that use novel reactions with common starting materials can be applied to produce fuels with suitable attributes for advanced fuel cycles. An example is provided based on the formation of uranium mononitride from dinitride starting material [2]. Uranium dinitride is air stable and can be produced from oxide starting material. Uranium dinitride pellets can be formed in air and then sintered under inert atmosphere to produce uranium mononitride. The unique method for the nitride synthesis can be coupled with established sintering techniques to produce fuel. These waste form and fuel illustrations exemplify the utility synthesis reactions can play in the future fuel cycles. Solution based separation of trivalent lanthanides from Am and Cm is also provided as an example of the utility of speciation and coordination chemistry in the nuclear fuel cycle. Soft donor ligands such as dithiophosphinic acids and bis-1,2,4-triazinylpyridine/bipyridine (BTP/BTBP) derivatives show significant separation selectivity. Many of these ligands are limited by poor stability, constrained working pH range, solubility in suitable solvents, and competition from counter anions. Various triazinyl and bis-triazinylpridine (H, Methyl, Ethyl, Pyridyl and Phenyl) derivatives have been synthesized and their complexation with Eu3+, Tb3+ and Cm3+ by time resolved laser fluorescence spectroscopy presented. The solvent is found to play a significant role in the complexation behavior and resulting speciation and coordination. In the acetonitrile medium, the complexes contain one ligand molecule per metal ion. Spectroscopic signatures change to ML3 species in methanol medium. For hard acceptors acetonitrile is known to be less solvating as compared to methanol. The Eu3+ ion, being a hard cation, is less solvated by acetonitrile and the nitrate counter anion strongly binds with it and the BTP molecules. When the Eu(III) complex of Py-BTP was prepared in acetonitrile medium, the single crystal XRD result shows that it acts as a tetra-dentate ligand with the stoichiometry Eu(Py-BTP)(NO3)3 resulting in 10 coordinated Eu(III) ion. The overall results show the utility of radioelement speciation, compound synthesis, and coordination chemistry in expanding general chemistry knowledge and the development of applications exploiting radionuclide synthesis, speciation, and coordination chemistry. 1. Weck, P.F., et. al Inorg. Chem. 48(14), 6555-6558 (2009). 2. Yeamans, C.B.,et.al J. Nucl. Mat. 347, 75-78 (2008).
Speaker: Prof. Kenneth Czerwinski (University of Nevada, Las Vegas)
• 123
Solid state diffusion interactions of metallic uranium with technetium
In metallic nuclear fuels, uranium will interact with fission products formed at higher burn-ups. Understanding the binary interactions between components is helpful in building a description of the overall system consisting of fuel and fission products. Many of the fission product metals are easy to obtain and study in reactions with metallic depleted uranium to simulate conditions in an active metallic nuclear fuel. Technetium is a major fission product (~ 6% from 235-U) and very little is known about its interaction with uranium: only one phase has been identified (i.e., U2Tc) and no Tc-U binary phase diagram is reported. In this study, the interaction between metallic uranium and technetium at elevated temperature has been investigated. Discs of uranium and technetium were prepared into a couple and heat treated at 1023 K for 120 h. After treatment, the couple was analyzed by Electron Microscopy and the U2Tc phase was identified. In order to better understand the physico-chemistry of binary alloys of uranium with transition metals, discs consisting of uranium with molybdenum, rhenium and ruthenium were prepared, heat treated at 1023 K and analyzed by Electron Microscopy.
Speaker: Prof. Ken Czerwinski (University of Nevada, Las Vegas, United States)
• 124
Application of Multi-Step Excitation Schemes for Detection of Actinides and Lanthanides in Solutions by Laser Specroscopy
Development of laser spectroscopy with tunable lasers gives rise to new procedures for detection of trace amounts of various substances in various media. A possibility to tune a wavelength of laser radiation allows selective action on certain atoms and molecules and, hence, selective detection of these species [1]. The practical application of laser spectroscopy to analysis of different samples is confronted with one essential difficulty, namely the element to be detected must be permanently located in the area of interaction with laser radiation. Therefore the use of solutions of the substances to be analyzed is the most attractive from the practical standpoint. When the pulse (1ns) UV radiation produced by nitrogen laser is used for lanthanide and actinide excitation in solutions the UV radiation is absorbed with different impurity molecules and as a consequence the background radiation is increased. Using short laser pulses for excitation of molecules and ions in liquids and time resolution for registration of luminescence or chemiluminescence produced by actinide and lanthanide ions we can separate target signals from short-lived background luminescence [1]. Selective excitation of detectable molecules can additionally decrease the intensity of background radiation. In addition, UV radiation is absorbed with chemiluminogen (luminol in our experiments) molecules, which makes difficult interpretation of the results. Therefore a key problem of chemiluminescence application to detection of lanthanides and actinides in solutions is an increase in the selectivity of detection. Appropriate selectivity of lanthanide or actinide excitation can be reached by initiation of transitions within 4f- or 5f-electron shell, which correspond to visible spectral range of absorbed laser radiation. Since the energy of one-quantum excitation in visible range may be insufficient for initiation of chemiluminescence it was proposed to excite lanthanide and actinide ion by multi-quantum absorption of visible light [1-3]. The use of laser radiation with tunable wavelength allows selective excitation of actinide or lanthanide species with subsequent registration of luminescence or chemiluminescence. The details of multi-step luminescence/chemiluminescence excitation in solutions are considered. It is shown that a multi-step scheme of luminescence/chemiluminescence excitation increase both the sensitivity and selectivity of lanthanide and actinide detection. References [1] Izosimov I.N., Phys. Part. Nucl. 38, 177 (2007). [2] Gorshkov N.G., Izosimov I.N., Mikhalev V.A. et al., Radiochemistry. 6, 525 (2012). [3] Izosimov I.N., Firsin N.G., Gorshkov N.G. et al., Joint Institute for Nuclear Research, Preprint E6-2013-37. Dubna (2013).
Speaker: Prof. Igor Izosimov (JINR)
• 125
Inverse quenching effect of excited U(VI) ions by Eu(III) ions in aqueous solutions
This talk will focus on energy transfer phenomena between hexavalent uranium (U) ions (U(VI)) and trivalent europium ions (Eu(III)). In the literature on this subject [1-3], the interaction between U(VI) and Eu(III) was explained as intramolecular energy transfer from excited U(VI) to Eu(III), and thus, the strong quenching of the luminescence of excited U(VI) by Eu(III) was observed. Because these earlier works were performed at relatively high U(VI) concentrations on the order of a few tens mM using conventional spectrofluorimetry, the precipitation of U(VI) at high pH values and the inner filter effect may interrupt the measurement of luminescence of U(VI). In this work, the time-resolved laser luminescence spectroscopy was adopted to verify the quenching effect of excited U(VI) by Eu(III) at relatively low U concentrations on the order of a few microM. Two types of uranium materials, dissolved U species in aqueous solutions and adsorbed U species onto a silica surface, were prepared with a solution pH range of 4-7. For both U materials, it is apparent that energy transfer between U(VI) and Eu(III) involves the formation of a hetero-polynuclear complex between the hydrolytic U(VI) and Eu(III) species. The new results observed in this work are as follows: (1) the (UO2)3(OH)5+ hydrolytic compound is the major species taking part in the energy transfer process, (2) the first rising part appeared in the luminescence signal waveform of Eu(III) implies direct evidence of energy transfer process from U(VI) to Eu(III), and (3) the negative quenching effect of U(VI) by Eu(III) ions, which represents the enhancement of luminescence of U(VI) with increasing Eu(III) concentration, was observed in aqueous solutions and the reason can be understood in terms of enhanced absorbance of U(VI) for a hetero-polynuclear complex. A similar negative quenching effect of U(VI) by trivalent terbium ions was observed in acidic solutions [4]. Characteristic features on the luminescence and absorption spectra for this complex will be discussed. [1] J.L. Kropp, J. Chem, Phys. 46 (1967) 843-847. [2] B.D. Joshi, A.G.I. Dalvi, T.R. Bangia, J. Luminescen. 10 (1975) 261-266. [3] S.P. Tanner, A.R. Vargenas, Inorg. Chem. 20 (1981) 4384-4386. [4] T. Yamamura, Z. Fazekas, M. Harada, H. Tomiyasu, Phys. Chem. Chem. Phys. 1 (1999) 3491-3496.
Speaker: Dr Euo Chang Jung (Korea Atomic Energy Reserach Institute)
• 126
Spectrophotometric and TRLFS speciation study of UO2(2+) - ChO4(2-) – H2O (Ch = S, Se) system
This experimental study seeks for stability constants $\beta_m°$, absorption $Z_m(\lambda)$ and fluorescence $Z_m(\lambda)$ spectra (including fluorescence lifetimes $\tau_m$) for the individual species of the general formula $[UO_2(ChO_4)_n]^{2-2n}$ (n $\in$ {0; 1; 2; 3}), specific ion interaction theory parameters $\epsilon(i,j)$ between uran-containing species and the most dominantly present ions ($Na^+, ClO_4^-, ChO_4^{2-}, HChO_4^-$) and their temperature dependence (for which the $\Delta H°$ for all present complex species is derived). Our study was done by preparing of several series of solutions (solutions differing by total sulfate/selenate concentration within the series and by total uranium concentration, pH and ionic strength between different series), measurement of the spectra (UV-VIS abs., TRLFS) and subsequent multilinear analysis (based on Singular Value Decomposition, Parallel Factor Analysis, …). The obtained results are compared with the previously measured data (our TRLFS spectra for uranyl-selenate complex species were, however, in the time of the abstract submission novel) and quantum chemical (ab initio and DFT) study, which part is presented on RadChem 2014 as well.
Speaker: Mr Jakub Visnak (Department of Nuclear Chemistry, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague)
• Radiation Chemistry 1 Red Hall

### Red Hall

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Conveners: Dr Sergey Stepanov (Institute of Theoretical and Experimental Physics), Václav Čuba (CTU in Prague - FNSPE)
• 127
Chemical and heavy ion irradiation induction of HPRT mutations in V79 cells
Induction of mutations has been observed in the HPRT locus of the Chinese hamster cells (line V79) after irradiation with accelerated heavy ions and also after the action of chemical agent. The mutant fractions were measured after exposure to two types of accelerated ions: 18O and 20Ne, under three different irradiation conditions. The linear energy transfer (LET) values ranged from 115 to 153 keV/µm. As a chemical agent, the ethanol was used. The dependence of the mutant fraction on expression time (the incubation period of the cells from termination of the irradiation until reseeding on a selective medium containing 6-thioguanine for the isolation of HPRT mutants) was measured for the doses of 0.5, 1, and 2 Gy; and for 1.65 M (10 vol. %) ethanol. The dependence was non-linear for all irradiation conditions. The mutant fraction increased with expression time, reached a maximum, and fell back to the starting level. It was found that after approximately 40 – 45 days (80 – 90 cell generations), mutant fraction returned to the levels typical for spontaneous mutants. The maximum of the mutant fraction on expression time relation was reached in different expression times under various irradiation conditions. The position of this peak was moving with the LET value of the used radiation. The observations were compared to the mutagenic actions of ethanol, which is a potent scavenger of hydroxyl radicals and it will be used in the upcoming research simultaneously with irradiation to observe its protective (or synergistic) effects.
Speaker: Mr Pavel Bláha (CTU in Prague, JINR)
• 128
Photo- and radiation-induced synthesis of (Ni,Zn)O or mixed NiO-ZnO oxides
Set of mixed oxide samples containing crystalline NiO-ZnO with variable composition was prepared by simple irradiation of aqueous solutions containing nickel and/or zinc nitrate hexahydrate, with subsequent annealing. Effects of various types of radiation were studied - solutions were irradiated either by accelerated electrons or UV light. Due to irradiation, weakly crystalline solid precursor was formed. After annealing at 200-300 °C, nanocrystalline (Ni,Zn)O or a mixture of NiO-ZnO oxides were formed, with different amounts of nickel or zinc, depending on the composition of initial solution. Due to high level of interaction between nickel and zinc compounds achieved, formation of solid solution was frequently observed even in the NiO-ZnO mixture. The size of the crystallites was calculated from XRPD spectra to be in order of tens of nm. Photo- or radiation- induced synthesis yields material with quality nanocrystals and very high specific surface area. This work has been supported by the Ministry of the Interior of the Czech Republic, project No. VG20132015132 and by the Grant Agency of the Czech Technical University in Prague, grant No. SGS14/207/OHK4/3T/14.
Speaker: Ms Lenka Procházková (CTU in Prague, Czech Republic)
• 129
Thermal condition monitoring methods applied to degraded cable insulations and jackets
Selection of condition monitoring (CM) method is an important aspect of cable ageing management for Nuclear Power Plants (NPP). The current status of cables might be inter alia assess by various thermal methods based either on Differential Scanning Calorimetry (DSC) or on Thermogravimetric (TG) analysis. The techniques might be used to determine the extent of cable damage caused either by degrading stressors occurring in a hot spot of NPP or by accelerated thermal and/or radiation aging performed in the laboratory. Using DSC apparatus Oxidation Induction Time (OIT) and Oxidation Induction Temperature (OITp) measurements might be carried out and the data obtained dependents on the remaining upon degradation content of antioxidants and the extent of oxidation. On the other hand, TG dynamic tests which theoretically might follow the changes in chemical structure of polymeric matrix are usually insufficiently sensitive to monitor progress of cable aging. Thus, finding other opportunities for such applications is currently a challenge. Our TG studies confirmed that for the cable insulations/jackets made of some polymers (EPR, EVA) tests conducted via an isothermal mode seem to be promising manner allowing for the diagnosis of gradual radiation aging. Variations in the TG thermograms for polymers degraded to different extents are substantial only if the experiments are performed in the aerobic atmosphere, whereas under nitrogen the changes are insignificant and can not be used for the evaluation of cable aging. During the first stage of tests the specimens were fast heated to 400 oC, i.e. to the temperature throughout which the thermal decay of hydrocarbon macromolecules starts. In the second step the samples were kept at 400 oC until the thermal decomposition of polymer. Functions of mass loss versus time for specimens irradiated to various doses were analyzed and compared. Surprisingly, the data confirmed that the more degraded insulations the higher thermal stability of the polymeric matrix measured as the time required to achieve assumed mass loss. The thermo-oxidation effects detected by the isothermal TG analysis are the consequences of chemical and physical changes occurring during radiation aging in the aerobic environment, such as oxidative degradation, formation of double bonds in the main chains improving thermal resistance, saturation of oxygen sensitive sites, barrier effects caused by flame retardant transformations, etc. It was also found that initial crosslinking of the polymers influences their thermo-oxidative stability. The effect was attributed to the raise of the rate of oxidation due to chain branching and increasing population of the labile bonds between third order carbon and hydrogen atoms. The method may not be considered as a condition indicator or an acceptance criterion but can provide information about the state of cable. Contrary to OIT and OITp measurements, the isothermal characteristic is not associated with the antioxidant content but rather with the extent of polymeric matrix degradation. The time necessary for achieving the selected ratio of mass loss might be confronted with other data characterizing progress of insulation/jacket aging, e.g. elongation at break, degree of swelling or density.
Speaker: Dr Grazyna Przybytniak (Institute of Nuclear Chemistry and Technology)
• 130
Influence of dose rate irradiation on polymers properties
Influence of dose rate irradiation on elongation at break, strength at break and density was evaluated on insulation of cables NSKFA, NSKA and CXFE-V. It was applied gamma irradiation and reactor ïrradiation. It was performed a experimental comparison among three dosimetry systems (alanine, oxalic acid, PFMCH) for reactor irradiation to evaluate the total dose and parts of neutrons and gamma.
Speaker: Dr Martin Cabalka (ÚJV Řež, a. s.)
• 3:00 PM
Coffee Break Marble Hall

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• Nuclear Analytical Methods 2 Mirror Hall

### Mirror Hall

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Reitenbergerova 4/95, Mari&#225;nsk&#233; L&#225;zn&#283;, Czech Republic <font color=white>
Conveners: Prof. Amares Chatt (Dalhousie University), Dr Zsolt Révay (Technische Universität München - FRM II)
• 131
Unraveling the reaction rate conventions for use in the k0 standardization of NAA
The majority of developers and users of the NAA k0 standardization do not realize that this method was launched [1] in terms of the accurate and generally applicable Stoughton-Halperin convention [2] for the description of the (n,γ) reaction rate. Later on, in the article reporting on the first k0-measurements [3], the more practical Høgdahl convention [4] was introduced instead (as had been done in earlier work on k-factors [5]), which was modified to account for a non-ideal (assumed 1/E1+α) epithermal neutron flux distribution thereby introducing Ryves’ concept of the effective resonance energy [6]. This resulted in a user-friendly protocol, which however ruled out some five (n,γ) reactions with a significant deviation from the ideal 1/v cross section dependence in the thermal neutron energy region. Although in the course of the years it was argued [7] that only a few excluded cases did not justify the changeover from a simple convention like Høgdahl’s to a more sophisticated one, finally the rigorously accurate Westcott convention [8] – with introduction of the α epithermal shape factor - was put forward to incorporate the non-1/v cases in the k0 standardization methodology [9]. Obviously, this turned out to be too complex and impractical for a good deal of the k0-NAA community, notably in the context of the Kayzero software [10] where use is made of an intermediate comparator factor defined in terms of the Høgdahl convention. Therefore, recently the “extended Høgdahl convention” [11] was launched, which takes into account the non-1/v cross section behavior by rather randomly inserting Westcott’s g(Tn) factor in the Høgdahl expression, where Tn is the maxwellian neutron temperature. Although the proof of validity of this extension was based on empirical and hardly on scientific arguments, it can nevertheless be regarded as a valid approach – as shown in the present paper where it is derived from the Stoughton-Halperin convention by introducing a few justifiable approximations. Hence, it can be smoothly implemented in the Kayzero software and in other concentration calculation programs while yielding for the 1/v and non-1/v (n,γ) reactions concentration results which are accurate to acceptable, respectively. This is a promising development in the context of the general applicability of the NAA k0 standardization. [1] A. Simonits et al., JRC 24 (1975) 31. [2] R.W. Stoughton and J. Halperin, Nucl. Sci. Eng. 15 (1963) 314. [3] A. Simonits et al., JRC 60 (1980) 461. [4] O. T. Høgdahl, Rept MMPP-226-1, Dec. 1962. [5] F. De Corte et al., JRC. 3 (1969) 205. [6] T. B. Ryves, Metrologia 5 (1969) 119. [7] F. De Corte et al., JRNC 113 (1987) 145. [8] C.H. Westcott, Rept CRRP-960/AECL, reprint 1962. [9] F. De Corte et al., JRNC 179 (1994) 93. [10] R. Van Sluijs, http://www.kayzero.com/ [11] R. Van Sluijs et al., 6th k0 Users Workshop, Budapest 2013, JRNC in press.
Speaker: Dr Frans De Corte ((ex) Ghent University, Belgium and Research Foundation, Flanders)
• 132
Re-determination of the half-life of 229Th
229Th is an alpha-decay nuclide of the neptunium decay series. Though already extinct in nature, 229Th occurs in high amount in spent fuel as the progeny of the long-lived 237Np. 229Th is one of the most widely used tracers in geology, environmental sciences or nuclear chemistry to determine 230Th and 232Th concentrations by mass spectrometry due to the relatively long half-life and to the fact that it does not occur in nature. 229Th as an isotopic tracer plays a special role in nuclear forensics, where its uncertainty associated with its concentration is one of the most dominant components in the uncertainty budget of radiochronometry of illicit nuclear materials1. As the 229Th standards are certified by activity concentration (e.g. Bq g-1), the accurate knowledge of 229Th half-life value is of utmost importance to convert it to amount content (e.g. mol g-1) needed for mass spectrometry. The first precise half-life measurement of 229Th was accomplished by Hagemann et al.2 and gave a value of 7340 ± 160 years. However, a later measurement by Goldstein et al.3 by isotope dilution mass spectrometry reported an approximately 7% higher half-life of 7880 ± 120 years. Recently, Kikunaga et al.4 measured the 229Th half-life by alpha spectrometry. Their half-life value of 7932 ± 55 years is consistent with the result obtained by Goldstein et al., and the authors suggest that the inaccuracy of the early half-life value is attributed to incomplete separation of 233U from its impurities. The aim of the present study is to re-measure the 229Th half-life using inductively coupled plasma mass spectrometry (ICP-MS) at lowest possible uncertainty. By the measurement of the 229Th amount content in the certified 229Th radioactivity standard (SRM 4328C), the half-life of 229Th can be calculated. The amount content of 229Th was determined by two independent methods, both traceable to SI. In the first method, the 229Th amount content was measured by isotope dilution ICP-MS technique, using a natural thorium certified reference material as a tracer. In the second method, the 229Th amount content was measured against a completely separated highly-enriched uranium solution. In this case, the applied uranium sample was completely purified from its thorium decay products beforehand at a well-known time. Thus the 230Th daughter product of the 234U, which serves actually as the tracer for the 229Th determination, can be very precisely calculated knowing the 234U content and the elapsed time between the uranium separation and 229Th determination1. Our measured 229Th half-life of 7921 years with an expanded uncertainty of 56 years (k =2) is in agreement with the latest values. Uncertainty was calculated according to the GUM (Guide for the Expression of Uncertainty in Measurement). The obtained value can help resolve the problem with 229Th half-life discrepancy, and can result in more precise age dating measurements both for geological and nuclear samples. References 1. Z. Varga, A. Nicholl, M. Wallenius and K. Mayer, Analytica Chimica Acta, 2012, 718, 25-31. 2. F. Hagemann, L. I. Katzin, M. H. Studier, G. T. Seaborg and A. Ghiorso, Physical Review, 1950, 79, 435-443. 3. S. J. Goldstein, M. T. Murrell and R. W. Williams, Physical Review C, 1989, 40, 2793-2795. 4. H. Kikunaga, T. Suzuki, M. Nomura, T. Mitsugashira and A. Shinohara, Physical Review C, 2011, 84.
Speaker: Dr Zsolt Varga (EC JRC Institute for Transuranium Elements)
• 133
Activation analysis in studies of tektites and impact glasses
Impact glasses and tektites are formed during fall of large meteorites on the Earth surface (impact) by melting and ejection of surface materials, mainly unconsolidated sediments and sedimentary rocks. In the Nuclear Physics Institute ASCR, methods of neutron and photon activation analyses have been utilized for detailed geochemical characterization of a collection of various tektites and impact glasses: Central European tektites - moldavites, Australasian tektites, impact glasses from the Zhamanshin crater in Kazakhstan - irghizites, and the Libyan Desert Glass. Geochemical analysis of a large representative set of moldavites indicates that a substantial part of their parent materials must have been, besides the surface molasse sediments, also soil layer and plant biomass which are indicated in modavite composition by enrichment in the plant nutrient/essential elements (K, Ca, Mg) and depletion of nonessential elements (Na, Rb, Sr, Ba), similarly to their redistribution during the transfer from soil to plants. The hypothesis has been supported also by analysis of carbon isotope composition of moldavites which is similar to that characteristic of land vegetation. In irghizites, determined contents of Ni, Cr, Mn, Fe and Co, after subtraction of their background contents from terrestrial source materials, allowed to assign the most probable impactor type as an ordinary L5 or L6 chondrite, and assess a range of the meteoritic fraction in the irghizite parent materials to 4 - 21 wt.%. An explanation has been suggested for lower Ir content in irghizites than matching a chondritic component which is based on significantly lower volatility of Ir compared to other meteoritic constituents as Ni, Cr, Mn, Fe and Co. Unambiguous assigning parent materials and finding a parent crater for the Australasian tektites (AAT) still remains an open issue. After critical evaluation and comparison with literature data, the geochemical data acquired in a representative set of AAT point to a "fingerprint" similarity between AAT and Chinese loess which was discussed in literature as a probable AAT precursor much earlier but later was doubted and abandoned due to generally accepted hypothetical location of the impact to Indochina. The data have been coupled with data available in literature for both AAT and their potential precursors on their isotopic composition (Sr, Nd, Li, B, cosmogenic Be-10). The results, together with considering geographical, ballistic and paleoclimatic aspects, put in serious doubt the location of the AAT parent crater in Indochina and bring extensive evidence for possible location of the crater in the deserts in north-central China which are the source area of the Chinese loess. Elemental composition of he Libyan Desert Glass (LDG) points to quartz sand as a main component of the parent materials, with admixture of elements implying an aluminosilicate component (clay minerals cementing quartz grains). A depletion of volatile elements (alkalis, Zn, As, Br, Sb, etc.) may reflect their evaporation loss during the impact. Higher Zr contents coupled with elevated contents of heavy rare earth elements may reflect melting of refractory zircon. LDG has recently been associated with the Kebira Crater on the Libya-Egypt border. The impact area was flooded with seawater during Cenomanian/Turonian stage and the assumed origin of LDG parent materials - compact sandstone with accessory minerals - in marine environment has been supported also by previous Li isotope investigation. No contamination of LDG by meteoritic material has been evidenced. The studies have been supported by the projects 205/09/0991 and 13-22351S of the Czech Science Foundation.
Speaker: Jiří Mizera (Nuclear Physics Institute, Academy of Sciences of the Czech Republic)
• 134
Neutron Depth Profiling with Multipixel Detectors
Neutron Depth Profiling (NDP) is a specific non-destructive nuclear analytical technique used for determination of depth distributions of some technologically important light elements (e.g., Li and B) in the near surface of solids. The NDP for thick samples (with a thickness > several micrometers) is utilized as a 1D profiling technique that enables to obtain a 1D depth distribution (assuming the uniform lateral distribution). In this case, the measurement is performed with a standard semiconductor detector (or a combination of several detectors arranged in a telescope, etc.) with high energy resolution that, consequently, also allows to obtain high depth resolution (~ 10 nm nominal resolution can be achieved). NDP for thin samples can (advantageously) adapt sophisticated detector systems that enable to detect both reaction products (emitted into opposite directions) simultaneously. Consequently, the sandwich arrangement of the NDP spectrometer (i.e., detector-sample-detector) can dramatically reduce (or even eliminate) the unwanted background and improve the detection sensitivity. Interestingly, as detector systems, placed on both sides of the inspected samples, multipixle detectors (e.g., Timepix, Medipix) can be utilized. Here, the first results of the 3D NDP with multipixle detectors are presented. As samples, thin polymeric foils with B or Li atoms, distributed in the microstructured arrays, were utilized. The obtained data showed that the 3D NDP version proved to be an interesting tool for analysis of the 3D micro-distributions of the NDP-relevant elements in thin samples. This capability might be attractive for electronic industry (where B or Li play an important role) or neutron micro-radiography. Acknowledgment: This study was supported by the Technological Agency of the Czech Republic (TACR) under the project No. TA01010237.
Speaker: Dr Jiří Vacík (Nuclear Physics Institute ASCR)
• 135
Determination of impurities in phosphoric acid by INAA
The increasing demand for phosphate fertilizers accounts for approximately 90 % of global phosphoric acid use. In the manufacture of phosphoric acid, thermal and wet processes are used. The thermal process has been abandoned for the production of phosphate fertilizers, because of the amount of energy which is needed. Decomposition of phosphate minerals with an acid, mostly sulphuric acid, is the only economic way to produce phosphoric acid. Phosphate ores, mostly in the form of apatite, are of two major geological types. The principal deposits are sedimentary rocks found, e.g., in Morocco, China, Algeria, Jordan, USA. Significant igneous deposits are found, e.g., in Russia, South Africa, Brazil. Whatever their origin apatites can be highly substituted and have variable compositions. More than 25 elements are known or proposed to substitute in the apatite structure [1]. The potentially hazardous elements found in phosphate rocks include As, Cd, Cr, Hg, Pb, Se, U, and V. Some cause difficulties in the reaction system, whereas others, soluble in phosphoric acid, may end up in the product acid. Therefore, there is a need for analytical method capable of accurate determination of the above and other elemental impurities in phosphoric acid. Instrumental neutron activation analysis (INAA) is a method of choice due to its multielemental capability and favourably low detection limits for most of the above elements. The problem is, however, that irradiation of liquid acids is prohibited in most nuclear reactors for safety reasons. Therefore, a sample preparation procedure is required that leads to “solidified” phosphoric acid. For this purpose, Silva et al. [2] employed precipitation with calcium hydroxide and evaporation for determination of uranium in phosphoric acid. In this work three other procedures were tested, namely (i) deposition of 100‑μL amounts of phosphoric acid onto disks of chromatographic paper Whatman 1 and sealing in polyethylene (PE) irradiation capsule without drying, (ii) precipitation of Ca3(PO4)2 with CaCO3 in a beaker, (iii) precipitation of (NH4)3PO4 by reaction with ammonia vapours in a dessicator (isothermal distillation of NH4OH [3]) directly in the PE irradiation capsules. The first procedure failed, because of breaking the PE capsules and consequent losses of their content on irradiation. In the second procedure, the activities of 47Ca‑47Sc and 49Ca increased background in the gamma‑ray spectra that impaired detection limits of trace elements, as well as blank values of Sr and several other elements due to impurities added with CaCO3. Thus, the third procedure appeared superior due to its simplicity and contamination-free nature. INAA results obtained with the third procedure are presented for four brands of phosphoric acid differing in purity (pro analysis and technical grades) and concentrations (75 %‑85 %). Acknowledgements This work was carried out within the IAEA Technical Cooperation project MOR 13014- MOR/1/007 and supported by the Czech Science Foundation, grant P108/12/G108. References [1] McClellan, GH (1980) J Geol Soc 137: 675‑681. [2] Silva, NC et al. (2009) J Radioanal Nucl Chem 281: 211‑213. [3] Veillon, C and Reamer, DC (1981) Anal Chem 53: 549‑550.
Speaker: Dr Jan Kameník (Nuclear Physics Institute, Academy of Sciences of the Czech Republic)
• 136
Development of 151Sm analytical method for the purpose of nuclear waste characterization
In France, nuclear wastes are managed by the French National Radioactive Waste Management Agency (ANDRA). Several repository sites have been built in order to accommodate nuclear waste packages. One is dedicated to the Low and Intermediate Level short-lived Waste. Criteria for 143 radionuclides have been defined by ANDRA which guarantee the safety of the facility. From this long list, 151Sm has to be declared as soon as its activity is over 0.1 Bq/g. The declaration threshold for this radionuclide is very low and the maximum acceptance level in waste packages has been fixed to 4.5 105 Bq/g. 151Sm is a fission product with a radioactive period of 90 year. As a pure beta emitter, it must be isolated from the matrices and the interfering radionuclides through chemical separations prior to any measurement. Consequently, a selective radiochemical procedure is needed to measure 151Sm in nuclear wastes. The LASE (Operator Support Analyses Laboratory) and Nuclab-Prod have shared their radio-analytical skills to develop an analytical method to measure 151Sm in radioactive waste. The analytical process includes 5 steps. First, digestion is performed for organic material, aqueous suspension or solid sample in nitric acid media. Neodynium as carrier and stable samarium as yield tracer are added. In order to reduce the salt concentration, a hydroxide precipitate is completed. Lanthanides are isolated from the other elements still present, by extraction chromatography using the Re-Spec column from Eichrom. A high performance liquid chromatography is implemented in order to separate samarium from the other rare earth element such as europium, neptunium, promethium…. Alpha-Hydroxybutyric acid as ligand agent is introduced in the mobile phase. Injected volume, eluent composition, fraction collection procedure have been optimized in order to assure recovery of Sm over 90%, no cross-contamination and effectiveness of the separation. This step has been completely automatized. The solution containing samarium is conditioned for liquid scintillation counting The presentation will first focus on the optimization of the radiochemical procedures and the way the various elements are discarded. The choice will be argued. The second part of the work will be addressed to the application of the method to nuclear waste, results will be discussed. Reference [1] ANDRA, NT ASCO.SP.ASRE.99.002 « Spécifications d’acceptations des colis de déchets radioactifs au centre de l’Aube (INB N°149) – spécifications générales – Spécification d’évaluation et de déclaration des caractéristiques radioactives»
Speaker: Dr Celine GAUTIER (CEA)
• Radiopharmaceutical Chemistry, Labelled Compounds 1 Red Hall

### Red Hall

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Conveners: Dr Alexander Popkov (Samo University), Dr Ondřej Lebeda (Nuclear Physics Institute, Academy of Sciences of the Czech Republic)
• 137
Pre-clinical evaluation of DOTA-conjugated PSMA-inhibitors and their comparison with standard reference Glu-urea-Lys-(Ahx)-HBED-CC
New theranostic radiopharmaceuticals for rapid visualisation of prostate cancer and the highly effective radioendotherapy are of utmost clinical interest. Since the Prostate-specific membrane antigen (PSMA) is upregulated in nearly all prostate cancers compared with the rather low expression levels in normal tissue, PSMA can be considered as an attractive target for the diagnosis and therapy of prostate cancer. This project is focused on the development and evaluation of a series of linker variations of DOTA conjugated 68Ga-PSMA-PET imaging agents. These ligands consist of three principle components: the PSMA binding motif (Glu-urea-Lys pharmacophore), a variable linker and the DOTA chelator. The combination of DOTA with the PSMA targeting inhibitors might open the possibility of using the same vector molecule for imaging and therapeutic purposes due to the similarity of the coordination chemistry of 68Ga and that of therapeutic radionuclides such as 90Y or 177Lu. All studied compounds were compared with the clinically used reference Glu-NH-CO-NH-Lys-(Ahx)-HBED-CC. It was reported that the chelator HBED-CC seems to interact advantageously with the binding pocket. The here aimed linker region is designed in order to elucidate the structure-activity relationships (SAR) and to compensate binding potential of HBED-CC. After the formation of the resin immobilized Glu-urea-Lys, the further synthesis of the PSMA binding motif and linker region was performed by solid-phase peptide chemistry. The resulting product was coupled by using the active ester of DOTA. All compounds were analysed using RP-HPLC, MALDI-MS, and NMR. Subsequent 68Ga-labeling resulted in a radiochemical yield (RCY) of >97% after 15 minutes at 95 °C for DOTA-conjugated compounds and in a RCY of more than 99% in less than 2 min for the HBED-CC-based compound. In order to select the most promising precursors, in vitro cell binding properties (competitive binding affinity and specific internalization) were studied using the PSMA expressing cell line LNCaP. The tumor-targeting and pharmacokinetic properties were further investigated through in vivo biodistribution studies and dynamic small animal microPET imaging. PET scans and biodistribution data were obtained 1 or 2 hours after injection in BALB/c nu/nu mice bearing LNCaP tumor xenografts. All prepared compounds revealed a high affinity for PSMA on the human prostate cancer cell line LNCaP. Of the library of 25 targeted probes synthesised two were found to bind the cells with low subnanomolar affinity (Ki = 0.07 ± 0.02 nM, and 0.49 ± 0.09 nM, respectively) which was significantly improved in comparison with the HBED-CC-based standard compound (Ki = 12.1 ± 2.1 nM). The inhibition potency investigated by the enzyme-based NAALADase assay confirmed these results. Both mentioned DOTA-conjugated imaging agents showed a higher specific internalisation of up to 48 % ID/106 cells which is crucial in respect to the tumor targeting properties. Taken together, these two substances showed improved cellular uptake compared to the reference Glu-urea-Lys-(Ahx)-HBED-CC. In addition, differences between the HBED-CC and the DOTA derivatives were observed also in the in vivo organ distribution studies. The lower kidney, liver and spleen values together with the higher tumor uptake were in favor of the DOTA compounds. Time-activity curves obtained from dynamic PET measurements showed prolonged tumor uptake and a faster clearance from the kidneys. Finally, the interaction with the binding pocket and the in vivo tumor-targeting and the pharmacokinetic properties of the DOTA-conjugated compounds were significantly optimized by modification of the linker region. This approach could lead to an improved management of recurrent prostate cancer with one and the same precursor for diagnostic and therapeutic purpose.
Speaker: Ms Martina Benešová (DKFZ Heidelberg)
• 138
Modified Inorganic Nanoparticles as a Vehicles for Alpha Emitters in Radionuclide therapy
Alpha particle emitting isotopes are in considerable interest for radionuclide therapy because of their high cytotoxicity and short path length [1]. Unfortunately, all available emitters have serious disadvantages: 211At forms weak bond with carbon atoms in the biomolecule and in the case of 212Bi, 213Bi and 226Th short half-life often limits the application of these nuclides. However, the short half-life of 212Bi and 213Bi could be effectively lengthened by binding the parent radionuclide 212Pb (t1/2 = 10.6 h) or 225Ac (t1/2 = 10 d) to a biomolecule, thereby effectively extending the use of short half-life 212Bi and 213Bi. In addition, in vivo generator delivers much greater dose per unit of administered activity compared to 212Bi and 213Bi alone. Also three radium radionuclides 223Ra, 224Ra and 225Ra exhibit very attractive nuclear properties for radiotherapy, but the lack of appropriate bifunctional ligand for radium was the reason why these radionuclides did not find application in receptor targeted therapy. In our studies we investigated the use of TiO2 nanoparticles as potential carriers for 225Ac/213Bi in vivo generator and nanozeolite particles as vehicles for 223,225Ra radionuclides. The TiO2 nanoparticles have unique properties like: high specific surface, high affinity for multivalent cations and simple way of synthesis, which are useful in the process of labelling. Commercially available (e.g. P-25 Degussa) and synthesised in our laboratory nanoparticles were used in experiments. The nanoparticles were characterized by TEM, SEM, DLS and NanoSight techniques. In our experiments we tested two different methods of labeling. The first one was based on the possibility of formation strong bonds with certain cations on the surface of the nanopraticles. In the second one, TiO2 nanoparticles were doped with 225Ac during the process of synthesis. In both cases we obtained high yields of labelling (>99%). Afterwards, the stability of labelled nanoparticles was examined in 0.9 % NaCl, 10-3 M EDTA, solutions of biologically active substances (cysteine, glutathione) and human serum. In case of TiO2 nanoparticles labelled with Ac-225, which was built in the crystalline structure, the leakage of 225Ac and its daughter radionuclides was not significant in any of solutions, even when the incubation time was extended to 10 days. In the case of nanoparticles with adsorbed 225Ac on surface the leakage in serum was slightly higher, but still insignificant. Also the NaA nanozeolite as a carrier for radium radionuclides has been studied. 223Ra, and 225Ra, the α-particle emitting radionuclides, have been absorbed in the nanometer-sized NaA zeolite through simple ion-exchange. 223,225Ra-nanozeolites have shown very good stability in solutions containing: physiological salt, EDTA, amino acid and human serum. To make NaA nanozeolite particles dispersed in water their surface has been modified with silane coupling agent containing poly(ethylene glycol) (PEG) molecules. To obtain conjugates specific for receptors on glioma cancer cells short peptide substance P were covalently attached to the PEG-TiO2 and PEG-nanozeolite surface. The obtained bioconjugate were labeled with 225Ac and 223Ra respectively. The serum stability of labelled biconjugates was similar or little better than unmodified nanoparticles. The cell affinity, cytotoxicity and biodistribution studies of the obtained radiobioconjugate are in progress. References D.Cordier, F.Forrer, F.Bruchertseifer, A.Morgenstern, C.Apostolidis, S.Good, J. Müller-Brand, H.Mäcke, J.C.Reubi, A.Merlo, Eur. J. Nucl. Med. Mol. Imaging 37 (2010) 1335–1344. Acknowledgments This work was supported by National Science Center of Poland (Grant 2011/01/M/ST406756)
Speaker: Prof. Aleksander Bilewicz (Institute of Nuclear Chemistry and Technology)
• 139
Determining the retention of recoiling daughter nuclides of 225Ac in polymeric nano-carriers
Alpha radionuclide therapy has a great potential in the fight against cancer as proven by a large number of pre-clinical and clinical studies. In vivo generators capable of delivering a highly efficient cascade of alpha particles are also steadily gaining importance. At the moment 225Ac is the most relevant radionuclide that can serve as an in vivo generator, providing four alpha particles with a total energy of 28 MeV. However, due to the recoil effects the daughter recoil atoms, most of which are alpha emitters as well, receive energies that are much higher (> 100 keV) than the energies of chemical bonds (typically around 2- 8 eV) resulting in decoupling of the radionuclide from common targeting agents such as antibodies. The escaped daughter atoms are free to spread in the body and can cause severe harm to healthy tissue, which is considered to be the major challenge in alpha radionuclide therapy. Here, we demonstrate that polymer vesicles (i.e. polymersomes) can retain recoiling daughter nuclei based on an experimental study examining the retention of 221Fr and 213Bi when encapsulating 225Ac. Furthermore, we examined the retention of 209Pb, the daughter nuclide of 213Po, when enclosing 213Bi in the vesicles. Polymersomes composed of poly(butadiene-b-ethylene oxide) were successfully loaded with 225Ac and 213Bi reaching an efficiency of more than 60 % in both cases with negligible loss. The recoil retention of 221Fr and 213Bi were found to increase with the size of the polymersomes, reaching respectively 69 ± 1.5 % and 53 ± 4 for polymersomes having a diameter of 800 nm. The retention of 209Pb subsequent to a single recoil step (i.e. 213Po decaying to 209Pb) was found to be 59 % ± 17 in the case of polymersomes having the same diameter as reported above. Finally, the polymersomes were found to accumulate around the nucleus in tumor cells (HeLa cell line) which is expected to further reduce the harm caused by recoiling alpha emitters, provided that the nano-carriers have favorable pharmacokinetics.
Speaker: Dr Antonia Denkova (TU Delft)
• 140
In vivo study of 111In-loaded polymersomes
In the fight against cancer, it is of utmost importance to damage diseased cells whilst leaving healthy tissue unaffected. Vesicles composed of amphiphilic block copolymers have been proven to be promising nano-carriers, which are capable of transporting a variety of pharmaceuticals to tumour sites [1]. Their application can be extended to the field of nuclear medicine by designing ultra stable polymersomes, although such studies are scarce. Here, we present a study demonstrating the radiolabeling of polymer vesicles with the molecular imaging agent 111In, and their in vivo pharmacokinetics in mice. This has been examined using microSPECT, the most powerful pre- clinical imaging technique in terms of spatial resolution. The vesicles are composed of poly(butadiene-b-ethylene oxide) block copolymers, and the labelling has been achieved by transportation of the radionuclide, complexed to a lipophilic ligand, through the hydrophobic bilayer into the aqueous cavity containing a strong hydrophilic chelate [2]. A sufficient amount of the radionuclides was successfully encapsulated in the polymersomes (>90 % loading efficiency) with a negligible loss of radiolabel upon incubation in serum (<5 % in 24 hours at 37 ˚C), allowing their safe application in in vivo studies. The 111In containing 80 nm polymersomes have been subsequently used in pharmacokinetic and bio-distribution studies using microSPECT. Both healthy and tumour bearing female Ncr nude mice were injected intravenously or subcutaneously with 80 nm polymersomes loaded with 20 MBq 111In. Periodic microSPECT images were taken, and a biodistribution was performed 24 and 48 h p.i. The polymersomes have been observed to circulate a considerable time in vivo (longer than 6 h) in healthy mice, and are primarily cleared by the spleen, which complies with the circulation time obtained in other in vivo polymersome studies [3]. This in contrast to a much shorter circulation time observed for polymersomes intravenously injected in tumour bearing mice, where the liver and spleen removed the polymersomes from circulation within 1.5 h. Saturation of the RES by saturation with a higher polymersome concentration is expected to prolong the blood circulation time of the vesicles. Very promising results were obtained for subcutaneously injected mice, where a high retention rate of polymersomes in the interstitial tissue surrounding the tumour site was observed, whereas unencapsulated 111In-DTPA was cleared immediately. This makes subcutaneously injected polymersomes a valuable option for loco-regionally targeted tumour therapy. References: [1] B.M. Discher, Y.Y. Won, D.S. Ege, J.M.C. Lee, F.S. Bates, D.E. Discher and D.A. Hammer, Polymersomes: tough vesicles made from diblock copolymers, Science 1999, 284, 1143  [2] G. Wang, R.M. de Kruijff, M.C.A. Stuart, E. Mendes, H.T. Wolterbeek and A.G. Denkova Polymersomes as radionuclide carriers loaded via active ion transport through the hydrophobic bilayer, Soft Matter 2013, 9, 727-734. [3] P.J. Photos, L. Bacakova, B. Discher, F.S. Bates, and D.E. Discher, Polymer vesicles in vivo: correlations with PEG molecular weight, J. Controlled Release 2003, 90, 323-334
Speaker: Ms Robin de Kruijff (Delft University of Technology)
• 141
Investigation of astatine chemistry in solution
Astatine 211 is considered to be one of the most promising candidates for targeted alpha therapy (TAT)[1,2] and it is the subject of a wide research program in Nantes (France). A carrier molecule should transport At-211 to the cancer cells where alpha-particles emitted by the radionuclide would destroy the target. However binding astatine to cancer selective carrier molecules remains a difficult task. It is recognized that many of the basic chemical studies with astatine (At) have unfortunately been set aside, which currently hinders the development of radiotherapeutic agents [3] At-211 is produced in cyclotrons and all investigations were consequently derived from radiochemical studies at ultra-trace concentrations (typically smaller than 10-10mol.L-1). Therefore no spectroscopic tools can be used to assess At chemistry at the molecular level. These two points clearly limit the investigations of its chemistry, and consequently the development of efficient labelling protocols. Based on these considerations, a research program has started to explore the fundamental properties of At using a multi-disciplinary approach combining radiochemistry, analytical chemistry and molecular modelling competences. The object of this contribution is to present the main advances obtained during the past 10 years as regards especially to the particular metallic character of astatine. Our methodology enabled to define a Pourbaix diagram (Eh/pH diagram) for At in non-complexing acidic aqueous medium. In addition to At- species, the experiments and quantum calculations highlighted the existence of two stable At+ and AtO+ cationic forms of astatine [4, 5]. This truly contrasts with others halogens. Recent results on the chemical reactivity of AtO+ demonstrate the potentiality to form both coordination and covalent bonds with organic and inorganic ligands [6-8]. The peculiarity of the AtO+ behaviour in water solvent will be also discussed [9,10]. REFERENCES [1] D. S. Wilbur, Current Radiopharmaceuticals, 2008, 3, 144-176. [2] G. Vaidyanathan et al., Current Radiopharmaceuticals, 2008, 1, 177-196. [3] D. S. Wilbur, Nature chemistry, 2013, 5, 246. [4] J. Champion et al., The Journal of Physical Chemistry A, 2010, 114, 576-582. [5] A. Sabatié-Gogova et al. Analytical Chimica acta, 2012, 721, 182. [6] J. Champion et al. Inorganica Chimica Acta, 2009, 362, 2654-2661. [7] J. Champion et al. Physical Chemistry Chemical Physics, 2011, 13, 14984-14992. [8] J. Champion et al. The Journal of Physical Chemistry A, 2013, 117, 1983-1990. [9] T. Ayed et al. The Journal of Physical Chemistry B 2013, 117, 5206−5211 [10] T. Ayed et al. The Journal of Physical Chemistry B, 117, 10589−10595
Speaker: Dr David Teze (CNRS)
• Poster Session - Chemistry of Actinide and Trans-actinide Elements
• 142
A Quantum Chemical Study on the Actinides Triflates An(OTf)n where (An= Th, U, Np, Pu, Am, Cm, Bk and No ); n= (3, 4)
The actinides triflates are formed from a central metal that relates to the ligands (CF3SO3-). The transition metal triflates (trifluoromethanesulfonates) are much considered as Lewis acid catalysts in a variety of organic reactions, as well as precursors in inorganic and organometallic synthesis. In coordination chemistry, the selective complexation of actinides (ш) over lanthanides (ш) with efficient extractant molecules is an important problem for both its fundamental aspects and its applications, in particular in the partitioning of spent nuclear fuels. We carry out a quantum calculation based on the density functional theory (DFT) of the actinide triflates complexes. Our aim is to study the structural proprieties changes of these complexes geometries. Furthermore we report the computational study on An(OTf)n where (An= Th, U, Np, Pu, Am, Cm, Bk and No ); n = (3, 4). The quantum calculation DFT proved that the trigonal prismatic geometry is favored for all the studied actinide complexes of the general formula An(OTf)3 where ( An= Th, U, Np, Pu, Am, Cm, Bk and No ) so as by the lanthanide triflate complexes; where the trigonal prismatic geometry is most distorted in the case of triflate thorium Th(OTf)3 and almost perfect in the case of U(OTf)3. The OTf group is bonded to the central metal An as a bidentate ligand with a number of coordination equal to six. For the An(OTF)4 where ( An= Th, U and Pu), the optimized geometry results showed a dodecahedron geometry. Differences in the structural parameters (bond, lengths and angles) can be attributed partly to the nature of the metal atoms and the structural arrangement of the studied compounds. Keywords: actinide- triflate- catalyst- DFT- trigonal prismatic.
• 143
Calculation of boiling temperature of seaborgium hexafluoride
The formulation of the Mendeleyev's Periodic law says: "Properties of chemical elements and their connections are in periodic dependence..." Therefore, it is possible to define evaluate unknown or by practical consideration inaccessible constants of some connections operating with various constants of similar substances in chemical behavior [1]. Chemical similar substances are connections with a close factor of intermolecular interaction (ψ-factor). They possess the actual identical chemical properties. For calculation and an assessment of unknown physical and chemical constants, in particular, boiling temperatures widely use methods of comparative calculation if temperatures of boiling of similar connections are known, for example. A boiling temperature is one of the main characteristic constants of any substance. For molecular connections there is the following dependence: (Tb•M) 0, 5 = f (M) (1) them Tb – a boiling temperature, К; M – molecular mass of substance, g-mol. Dependence (1) is a straight line for similar in the chemical relation of hexafluorides of the chrome, the molybdenum and the tungsten, and also uranium. According to works [2-4] character of a chemical bond in CrF6 molecules (ψ = < 0, 05), UF6 (ψ = 0,028), MoF6 (ψ = 0,038) and WF6 (ψ = 0,028) is mainly covalent, i.e. these connections define as molecular. Chemical element No 106 which has the name "seaborgium", is chemical analog of elements of a chrome subgroup. It is possible to tell surely that seaborgium forms molecular hexafluoride, though possessing considerably smaller oxidizing ability in comparison with MoF6 and even with WF6 [4]. Function (1) was applied to calculation of boiling temperature of seaborgium hexafluoride, it was equal 355 K. Literature 1. L. Pauling General Chemistry. Freeman, San Francisco, 1970. 2. K. Ohwada On the ionic and covalent characters of uranium-fluorine bonds in complex fluorides of uranium. // J. Inorg. nucl. Chem., 1976, vol. 38, No 4, pp. 741-745. 3. A.G. Morachevsky, I.B. Sladkov Physical and chemical properties of molecular inorganic connections. – L.: Chemistry. 1987 . p. 59. 4. T.A. O´Donnell, A.B. Waugh and C.H. Randall Reactivity of transition metal fluorides. Part IX. // J. Inorg. nucl. Chem., 1977, vol. 39, No 9, pp. 1597-1600.
Speaker: Dr Oleg Gromov (Borisovich)
• 144
Electrolytic reduction studies of Mo and W towards the reduction of seaborgium
Seaborgium (Sg), element 106, is the third transactinide element placed at the 7th row of the Periodic Table. Similar to its lighter group-6 homologs, Mo and W, Sg is expected to be redox-active in aqueous solutions. Pershina et al. [1] theoretically calculated the redox potentials of various couples of Sg on the basis of its multiple ionization-potentials [2]. They predicted that the redox couples of Sg such as Sg(VI)/Sg(V) and Sg(VI)/Sg(IV) have a more negative redox potentials than those of the corresponding Cr, Mo, and W ones in acidic solutions [1]. This is because the reduction processes of Sg are associated with its lower ionization potentials due to the large destabilization of 6d atomic orbitals [1]. Experimental determinations of redox potentials of Sg, therefore, provide tests of these theoretical predictions and yield information on the stability of the valence 6d orbital. The best Sg isotope for chemical investigation is 265a,bSg (a and b denote the ground and isomeric state) produced in the 248Cm(22Ne, 5n)265a,bSg reaction. Because of low production rates of 265a,bSg and their short half-live of 8.5 s and 14.4 s [3], respectively, only single atoms of Sg are present during an experiment. Standard electrochemical techniques are, thus, not applicable to reduction studies of Sg. Furthermore, continuously rapid experiments are required to efficiently separate reduced and non-reduced species and to measure the alpha decay of 265a,bSg within its lifetimes. We are, therefore, developing a novel chemistry assembly consisting of a membrane degasser, a flow electrolytic column (FEC) [4], and the continuous liquid-liquid extraction apparatus SISAK coupled with a liquid scintillation counting system [5] to carry out a continuous reduction experiment of Sg. The development of suitable liquid-liquid extraction schemes are described in a separate contribution [6]. In this contribution, electrolytic reduction of Mo and W using a FEC to prepare the reduction experiment of Sg is presented. We carried out batch-wise electrolytic reduction of carrier-free 93mMo and 176,181W radiotracers using a FEC. The electrolyzed samples from a FEC were chemically analyzed by solvent extraction with TOA and HDEHP to separate and identify reduced species from the stable Mo(VI) and W(VI) ones based on their different extraction behavior. 93mMo and 176, 181W were applied as radiotracers. We also performed cyclic voltammetry and UV/Vis absorption spectrometry of macro amounts of Mo and W in acidic solutions to obtain information on redox reactions of these elements under given conditions. In this conference, the present status of the preparatory reduction experiments with Mo and W will be presented. [1] V. Pershina et al., J. Phys. Chem. A 103, 8463-8470 (1999). [2] E. Johnson et al., J. Phys. Chem. A 103, 8458-8462 (1999). [3] H. Haba et al., Phys. Rev. C 85, 024611-1-11 (2012). [4] A. Toyoshima et al., Radiochim. Acta 96, 323-326 (2008). [5] J. P. Omtvedt et al., Eur. Phys. J. D 45, 91-97 (2007). [6] M. Attallah et al., contribution to this conference
Speaker: Dr Atsushi Toyoshima (Japan Atomic Energy Agency)
• 145
Gas phase chemistry of the volatile chloride compound of Hf isotopes
Gas-phase chemistry is one of the most utilized techniques to study chemical properties of superheavy elements. An adsorption enthalpy of volatile compounds of these elements can be determined with their adsorption-desorption processes on a gas chromatographic column surface. The gas phase chemistry for group 4 elements, Zr, Hf, and Rf has been performed by several groups, and it is reported that the order of the volatility of their tetrachlorides is Zr≧Rf>Hf [1, 2] and Zr~Hf~Rf [3]. However, in macro-scale, tetrachloride of Hf is known to be more volatile than that of Hf. Until now, we have investigated gas chromatographic behavior of volatile chloride compounds of Zr and Hf, and the transfer process in the column using Hf radioisotopes of various half-lives. The results show a similar behavior with nonvolatile compound, oxychloride which is formed by oxygen in a system [1]. Therefore, we investigated in detail oxygen effects on a gas chromatographic behavior. Hf isotopes were produced in the natEu(19F,xn) and 152Gd(18O,xn) reactions using 20 MV tandem accelerator at Japan Atomic Energy Agency (JAEA). The beam energy of 19F and 18O were 122 and 108 MeV, respectively. Produced Hf isotopes were 165Hf (76 s), 166Hf (6.8 min), 167Hf (2.05 min). To compare volatility with a Zr compound, 85Zr (7.9 min) was also produced in the natGa(19F,xn) and natGe(18O,xn) reaction. Nuclear reaction products were transported to the gas chromatographic apparatus with a carbon cluster in a helium gas flow. The transported products were collected on quartz wool plugged in a quartz tube where HCl gas added to form volatile chloride compounds. Oxygen gas was also introduced in order to examine an oxygen effect on a gas chromatographic behavior. The volatile compounds through the isothermal column were re-transported using a He/KCl gas-jet system, and collected in a cold trap where gamma-rays were measured to obtain the yield of each Hf isotope which passed through the column. The relative yields for 165,166,167Hf and 85Zr are regarded as 100% at the column temperature of 450 C. In the condition of oxygen free, the yields of all nuclides increased with the temperature of the column from 200 C up to 300 C. When oxygen was added into the system, the yields at 300 C were very low and the temperature to which the yield reaches to 100 % was 400 C. Since this result agrees with our previous results, it is found that oxygen had actually influenced the chromatographic behavior reported until now. In the model generally used for analysis of the gas-phase chemistry, it is explained that the yield of the volatile compound changes according to the half-life of the nuclide used. But our experimental results show that nuclides of different half-lives exhibit almost the same breakthrough curves in an isothermal chromatography. The detailed reason is under investigation. [1] A. Tuerler et al., J.Radioanal. Nucl. Chem. 1992, 160, 327-339 [2] B. Kadkhodayan et al., Radiochim. Acta 1996, 72, 169-178. [3] T. K. Sato et al., J. Nucl. and Radiochem. Sci. 2005, 6, N1-N3.
Speaker: Prof. Hisaaki Kudo (Niigata University)
• 146
Measurement of the First Ionization Potentials of Short-lived Lanthanides Using a Surface Ionization Method
The first ionization potential (IP) directly reflects a valence electronic configuration influenced by relativistic effects which are significantly noticeable for heavy elements. Information on IP of heavy elements, therefore, gives us a better understanding of relativistic effects. IPs of heavy actinides with atomic number Z > 100, however, have not been measured by conventional techniques, such as resonance ionization mass spectrometry (RIMS), because these elements are only available in non-weighable quantities down to the one-atom-at-a-time scale. This condition forces us to call for a different experimental approach. Here, we have focused on a surface ionization process. Since the surface ionization process takes place between an atom and a metal surface, this method is applicable to one-atom-at-a-time scale experiments. In fact, we ionized and mass-separated short-lived isotopes using the surface ionization method installed in the JAEA-ISOL system [1]. Further improvement of the surface ionization type ion-source has been recently applied to measure the IP of lawrencium (Lr, Z = 103). 27-s 256Lr produced in the 249Cf + 11B reaction was successfully ionized [2]. The IP measurement of Lr is now under way. In this work, we measured ionization efficiencies of various short-lived lanthanides and evaluated their IPs, as a test experiment for measurement of IPs of heavy actinides. Short-lived lanthanides, 143mSm, 143Eu, 148mTb, 154Ho, 157Er, and 165Yb, were produced by the irradiation of a 67.9- MeV 11B4+ beam delivered from the JAEA tandem accelerator on 136Ce / 141Pr / 159Tb and 142Nd / 147Sm / natEu targets. Short-lived 168Lu was also produced in the reaction of 162Dy with a 11B4+ beam. Nuclear reaction products recoiling from the targets were transported to the ion-source of the JAEA-ISOL set up by a He/CdI2 gas-jet transport system. The products were ionized in the ion-source, accelerated with 30 kV, mass-separated, and collected on an aluminized Mylar tape. The amounts of the collected ions were determined by gamma-ray measurement with a HP-Ge detector. To calculate ionization efficiencies, the amounts of the transported products were also determined by direct collection using a separate catcher system. IPs of various short-lived lanthanides are evaluated based on the following Saha-Langmuir equation: α= n_i/n_0 =exp((φ-IP)/kT) , where n_i and n_0 indicate the number of ions and that of atoms on a metal surface, respectively. T, k, and φ are the absolute temperature of the metal surface, the Boltzmann constant, and the work function of the specific metal surface, respectively. The experimental ionization efficiency β is expressed by using the α as follows: β= n_i/(n_0+n_i )= α/(α+1) . Obtained IP values of short-lived lanthanides with tracer scale atoms were compared with literature values measured with macro-scale amounts of these elements. [1] S. Ichikawa, et al., Nucl. Instr. and Meth. A 374, 330 (1996). [2] T. K. Sato, et al., Rev. Sci. Instrum. 84, 023304 (2013).
Speaker: Mr Yusuke Kaneya (Graduate School of Science and Engineering, Ibaraki University / Japan Atomic Energy Agency)
• 147
Mechanism of addition-fragmentation reaction of thiocarbonyls compounds in free radical polymerization. A DFT study
In the present study we analyze the reaction mechanisms involved by Xanthates (SA(C@S)AO) and Thiocarbonates (OA(C@S)AO) compounds in a reversible addition fragmentation chain transfer (RAFT) polymerization. For the purpose, theoretical calculations have been performed by means of density functional theory (DFT), using the B3LYP, M06, CAM-B3LYP, LC-xPBE exchange correlation functionals and 6-31G⁄ basis sets. Thanks to the transition state theory, the rates of addition and fragmentation reactions were obtained. It is shown that, for these systems, the fragmentation step is more selective than the addition step, and that the range-separated functionals give results close to the experimental trends.
• 148
Preliminary investigations towards the separation of hexavalent and tetravalent seaborgium - extraction of homologs
Element 106, seaborgium (Sg) is a group-6 element with the lighter homologs tungsten (W) and molybdenum (Mo). The homologs have several stable oxidation states in aqueous solutions. Therefore, one can empirically expect that Sg should exhibit similar properties. In addition, theoretical estimates of redox potentials of group-6 elements show that Sg can be reduced from the most stable hexavalent state to a lower oxidation state [1]. The aim of the present study is to find a suitable chemical extraction and separation system to be applied in future reduction studies of Sg [2] to distinguish and isolate reduced species from Sg(VI) by its different extraction behavior in a subsequent liquid-liquid extraction stage. Our strategy to achieve this is to identify a chemical system where the reduced and non-reduced species in solution have opposite charge. It should then be possible to distinguish between them by simply using a cation or anion extraction agent. Details of the strategy and overall system for performing liquid-phase redox studies on seaborgium will be presented in a separate contribution to this RadChem conference [3]. The extraction behavior of Mo(VI) and W(VI) from HCl with Hinokitol in toluene has been investigated in our previous work [4]. In the present work, we have focused our investigation towards systems where reduced species are anionic and hexavalent ions are cationic. Radiotracers of 89Zr and 93mMo was used to represent reduced species of Sg(IV) and non-oxidized Sg(VI), respectively. 0.1 M solutions of H2SO4, HCl, and HClO4 with and without 0.01 M HF were investigated. Di-(2-ethylhexyl)phosphoric acid (HDEHP) and Tri-n-octylamine (TOA) dissolved in toluene were used as extraction agents. The Oslo Cyclotron Laboratory's (OCL) MC35 Scanditronix Cyclotron was used for producing the 89Zr and 93mMo radiotracer. While all these experiments were performed as discontinuous "batch" extractions, in the future, on-line studies will have to be performed using the full on-line and automated system (SISAK with a redox cell, see [3] for details) to test realistic conditions for a Sg experiment. 30 MeV 4He2+ ions, delivered with an intensity of ~350 nA (electrical), were used for the nuclear reactions natZr(α,x)93mMo and natSr(α,x)89Zr. The activity was then transported in a KCl gas-jet and was deposited on a filter paper. This was gently washed off using the desired aqueous solution. The solution was mixed with an organic extractant dissolved in toluene and was violently shaken for 5 min using a Vortex shaker. Using H2SO4 + 0.01 M HF with either 0.1 M HDEHP or 0.1 M TOA gave the best separation between Mo and Zr. The obtained results indicate that a solution of 0.1 M H2SO4 + 0.01 M HF with 0.1M HDEHP provided the best separation: 88% Mo(VI) and 12% Zr(IV) were extracted. This is a promising start to develop suitable conditions for a future element 106 (Sg) experiment. These experiments will be presented in more detail. Preliminary data of the reduction of Mo(VI) to Mo(IV) using a Flow Electrolytic Column (FEC) [5] in combination with a promising extraction system will be presented by Toyoshima et al. in a parallel contribution to this conference [2]. References [1] V. Pershina, E. Johnson, and B. Fricke. “Theoretical Estimates of Redox Potentials for Group 6 Elements, Including Element 106, Seaborgium, in Acid Solutions”. In: The Journal of Physical Chemistry A 103 (1999), pp. 8463–8470. [2] A. Toyoshima et al., contribution to this conference [3] J.P. Omtvedt et al., contribution to this conference [4] S. Miyashita et al. ‘’Solvent extraction of hexavalent Mo and W using 4-isopropyltropolone (Hinokitol) for seaborgium (Sg) reduction experiment’’ APSORC 13, Kanazawa – Japan. [5] A. Toyoshima et al. “Development of an Electrochemistry Apparatus for the Heaviest Elements”. In: Radiochemica acta 96 (2008), pp. 323–326.
Speakers: Mr H. V. Lerum (Chemistry Department - University of Oslo), Dr Mohamed F. Attallah (Chemistry Department, University of Oslo, Norway)
• 149
Study of Np(V) complexation with propionate and lactate at room temperature
A.N. Vasiliev1,2, N. L. Banik1, R. Marsac1, C. M. Marquardt1, S. N. Kalmykov2 1Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal, 76021 Karlsruhe, Germany 2 Lomonosov Moscow State University, Department of Chemistry, 119991 Moscow, Russia Np-237 is one of the important contributors to the radiation inventory of nuclear waste repositories over a very long time period, because of its long half-life (2.14•106 y). Natural clay rocks are considered as potential host rocks for deep geological disposal of nuclear waste, because of their low permeability and high retention properties for radionuclides via sorption processes. However, small organic molecules, such as lactate and propionate exist in clay rock pore water and they might enhance Np mobility. The understanding of the complexation of Np with these ligands and reliable complex formation data are required in the frame of safety assessment of a nuclear waste repository. Two methods were applied and compared for the determination of Np(V) (NpO2+) complexation with propionate ([Prop] = 0-0.30 mol/L) and lactate ([Lact] = 0-0.33 mol/L), namely UV-Vis/NIR spectroscopy and liquid-liquid extraction (LLE) technique with isoamyl alcohol solution containing 10-3 M TTA and 5•10-4 M 1,10-phenanthroline [1]. All measurements were performed at 0.5 M ionic strength of NaCl solution at room temperature (22±1 °C). The concentration of 237Np(V) in LLE experiments was 1∙10-6 - 3∙10-6 M at pH 7. Liquid scintillation counting was used for the determination of the neptunium concentration in aqueous and organic phases after the extraction. UV-Vis/NIR spectroscopy measurements in the wavelength range of 950-1030 nm were carried out at pH 4, 5 and 7 with 237Np(V) concentrations of 2∙10-5 - 6∙10-5 M. The maximum of the absorption band of the neptunyl aqua ion (NpO2+) at 980 nm shifts with increasing ligand concentration to 983 nm (NpO2Prop) and 986 nm (NpO2Lact) while its absorption intensity decreases. Slope analysis of the results yields a 1:1 Np(V) complex formation for propionate and lactate at the given pH values. In the extraction experiment, the distribution ratio of [Np-org]/[Np-aq] decreases with increasing ligand concentration. Both methods provided similar conditional complexation constants at ionic strength of 0.5 M NaCl: log Kc (spec) = 1.09±0.1 and log Kc (LLE) = 1.04±0.02 for NpO2Prop; log Kc (spec) = 1.75±0.1 and log Kc (LLE) = 1.85±0.01 for NpO2Lact. The value for the lactate complex is comparable with a value from literature: log Kc (spec) = 1.78±0.03 for NpO2Lact I = 0.3 M [2]. The complexation strength of propionate is similar to the acetate complexation expressed in a similar complex formation constant of log Kc (spec) = 1.05±0.04 for NpO2Acet at I = 0.3 M [2]. The work will be extended to different ionic strengths and elevated temperatures in the near future. References: [1] Y. Inoue, O. T. (1982). "Solvent extraction of neptunium (V) by thenoyltrifluoroacetone and 1,10-phenanthroline or tri-n-octylphosphosphine oxide." Radiochimica Acta 31: 193-196. [2] R. C. Moore, M. G. Bronikowski (1999). "Thermodynamic modeling of actinide complexation with acetate and lactate at high ionic strength." Journal of Solution Chemistry 28(5).
Speaker: Mr Aleksandr Vasiliev (Moscow State University)
• 150
Superheavy Element Chemistry Through Highly Accurate Small-Core Pseudopotential Model
Recent advances in first-principle based studies of superheavy element (SHE) chemistry using the new accurate small-core pseudopotential model are summarized. This model accounts for the finite nuclear size and effectively incorporates most relativistic effects described by the all-electron Dirac—Coulomb—Breit model (including the bulk of Breit interactions) and enables explicit correlation of both valence and subvalence electrons. It provides thus a good basis for attaining optimal accuracy/cost ratio in the cases of large and strongly interfering relativistic and correlation effects characteristic for the SHE compounds. Depending on the size of systems under study and required accuracy, high-level relativistic wavefunction theory (mainly coupled-cluster) and density functional theory methods or their combinations were used to solve the electron correlation problem. Synthesis and chemical identification of new superheavy elements is of top interest during the last decade. Since the thermochromatography on gold has been proved to be a unique method of chemical detection of heaviest elements, main attention was paid to the description of the SHEs – gold interactions. Adsorption energies of SHEs on gold surface were estimated using the cluster model. Its reliability was improved by monitoring charge distributions in the vicinity of the adsorption site and taking into account the effects of relaxation of the cluster compatible with its embedding into the crystal. In some cases the results differ significantly from those of previous theoretical studies. For instance, the new estimates of element 113 and element 120 on gold adsorption energies (1.0-1.2 eV and 2.5-2.7 eV respectively [1, 2]) are recommended. Further development of the SHE “chemical” identification techniques may benefit from having a broader view of their chemical properties. We performed systematical relativistic calculations of molecular structures and energetics of presumably stable binary compounds of SHEs with the most common light elements. We focus on the properties of element 120, copernicium (E112) and flerovium (E114) which are expected to display particularly strong relativistic contraction and stabilization of the filled s or p1/2 subshells. The obtained results along with the similar data for the homologues of SHEs were visualized through the “chemical graphs” which reflect the main trends in changing basic gas-phase chemical properties of the elements in the given group of the Periodic table and demonstrate the specificity of SHEs [3]. The work is partially supported by the RFBR (grants # 13-03-01234, # 13-03-01307 аnd # 13-03-12252-ofi_m-2013). Thanks are due to Prof. C. van Wüllen for supplying us with his relativistic DFT code. The calculations were performed at MCC NRC “Kurchatov Institute” (http://computing.kiae.ru/). 1. A.A. Rusakov, Yu.A. Demidov, A.V. Zaitsevskii // CEJP (Rapid Comm.), 11, 1537-1540 (2013) 2. Yu. Demidov, A. Zaitsevskii and R. Eichler // PCCP (Rapid Comm.) 16, 2268-2270 (2014) 3. Yu. A. Demidov, A. V. Zaitsevskii // Radiochemistry 55, 461-465 (2013)
Speaker: Mr Yuriy Demidov (PNPI)
• 151
Synthesis and Research of the Hydrated Oxide U(VI) with General Formula UO3•2.25H2O
A new method of synthesis of schoepite [(UO2)8O2(OH)12](H2O)12(UO3•2.25H2O) has been proposed in this work. Dehydration process of the synthesized compound has been studied, the state and role of H2O in the structure has been established by mean of high-temperature X-ray diffraction, IR spectroscopy and thermography. The transformation processes of schoepite in other forms of the hydrated oxide U(VI) have been investigated. The individual crystalline phases of schoepite were synthesized by the two stages process. Earlier UO4•2H2O was prepared and decomposed into UO3 at 200°С. Thereafter this freshly obtained uranium (VI) oxide was hydrated by water vapor at 100°С. An IR spectroscopic study was carried out in order to evaluate the functional group composition, the state of H2O molecules and the state hydroxide groups in the structure of schoepite. The IR spectrum of UO3•2.25H2O contains three groups of absorption bands. Among these bands there are vibrations of H2O molecules, UO-H group and uranyl bonds. In schoepite all H2O molecules forms two types of H-bonds. First type of bonds is formed by the interaction of H2O molecules with each other. Interlayer H2O molecules and hydroxide groups, which are included in the structure of layer, interact and form other type of H-bond. The average intensity pick of ν (UO-H) appears in the spectrums at 3356 см-1. Corresponding bands of δ (U-O-H) vibrations are intensive ones at 997 см-1. For detailed determination of the schoepite structure and its resistance to high temperatures, a thermographic investigation has been carried out. Two Н2О molecules is removed [(UO2)8O2(OH)12](H2O)12 in one stage according to the first endotherm effect at 80–116°С. A new crystalline phase of meta-schoepite [(UO2)8O2(OH)12]•(H2O)10 is formed as a result of these processes. This compound is stable at room temperature. The process of the meta-schoepite thermal decomposition occurs in one stage according to the second endotherm effect in the temperature range of 118–156°С. The dehydration product ([(UO2)8O2•(OH)12](H2O)2) could not be obtained as the individual phase, because two Н2О molecules per formula unit of the compound are insufficiently for binding of the layers in the stable formation. At intermediate values of from 2 to 10 compound [(UO2)8•O2(OH)12](H2O)n should be regarded as a crystalline phase of variable composition, related to the class of solid solutions with different content of molecular water. The dehydration product with formula [(UO2)8O2(OH)12](H2O)2 (UO3•H2O) isomerizes in to α-modification of uranyl hydroxide α-UO2(OH)2. The condensation of hydroxide groups in α-UO2(OH)2 and formation UO3 occurs at the third endotherm effect at 289–361°С. This oxide decomposes to U3O8 at 500°С. Thus schoepite, meta-schoepite and uranyl hydroxide contain the similar structure units such as Н2О molecules, uranyl and hydroxide groups. Different combination of these structural units is a reason of existence of a variety of chemical forms of UO3•nH2O.
Speaker: Ms Kseniya Chaplieva (Aleksandrovna)
• 152
Synthesis and study of Lithium Triuranate Li2U3O10⋅6H2O
In this work, a method of synthesis of lithium triuranate hexahydrate Li2U3O10⋅6H2O is described. The chemical and functional composition of this compound has been investigated; its crystallographic characteristics have been determined; the state of Н2О and its role in the formation of the structure have been studied. Synthesis of the investigated compound is а reaction of shoepita UO3•2.25H2O with aqueous solution of lithium nitrate under hydrothermal conditions at 200OC. The synthesized lithium triuranate hexahydrate is an easily reproducible individual crystalline compound. The X-ray diffraction picture contains a series of reflections from planes with indices which, in combination with an intense reflection peak at 2θ= 12.04°, indicate a typical layered structure of the triuranate. For evaluation of its functional composition of Li2U3O10⋅6H2O, we have performed the IR spectroscopic research. The spectrum contains two groups of vibrations associated with Н2О and uranyl group. The vibrations of Н2О are very characteristic. The band of δ(Н2О) vibrations at 1620 cm–1 is not split. Due to the participation of Н2О molecules in the formation of the branched system of H-bonds, the bands of vibrations νs and νas represented in the spectra by a broad and intense band with faint maxima at 3511 and 3414 cm–1 . On the whole, all Н2О molecules in the IR spectrum of Li2U3O10⋅6H2O retain their vibrational identity. The vibrations of the uranyl group are represented in the spectrum by the only band νas at 917 cm–1, which is typical for the seven-fold coordination of uranium(VI) in its uranium–oxygen polyhedron. The absence of the band allows us to consider the uranyl group as having a linear and the equal-shoulder configuration. To specify the state of Н2О in Li2U3O10⋅6H2O and to estimate its position in the structure, we have performed thermographic study. According to the first effect in the DTA curve at 162°С, the elimination of four Н2О molecules per Li2U3O10•6H2O formula unit proceeds in a single stage. The elimination of the two additional Н2О molecules also proceeds in a single stage, but at a higher temperature 393°С. The dehydration process is completed at 393°С by the total destruction of the crystal structure and the transition into the amorphous state. The crystallization of Li2U3O10 over wide time and temperature ranges occurs above 393°C.
Speaker: Ms Elena Kostrova (Leonidovna)
• 153
The investigation of uranyl vanadates state in the saturated aqueous solutions
The state of uranyl vanadates with formula Ak(VUO6)k*nH2O (Ak –elements of the I-III groups of Periodic system) was investigated in aqueous solutions. The study of these compounds are interested because of their low soluble in aqueous solutions and the compounds are likely to form at the contact with the nuclear waste in the environment, therefore Ak(VUO6)k*nH2O can be used to bind uranium. Thereby it is necessary to investigate the state, stability, solubility, conversion of uranyl vanadates in aqueous solutions. It is shown that pH has the most significant impact on the state of uranyl vanadates in heterogeneous water-salt systems. The pH of the aqueous solution defines the range pH of uranium existence, the type and solubility of the secondary phases. On the whole, it was established that uranyl vanadates are inconvertible at the contact with the aqueous solutions in the wide acid-base range. Their structure and composition preserve in heterogeneous water-salt systems at pH from 1-2 to 11-12. Out of the pointed interval the structure of uranyl vanadates destructs and compounds with another composition and structure form and are in the equilibrium to the aqueous solution. A type of formed compounds depends on pH. In acidic media at pH ≤ 1-2 initial compounds convert into the amorphous V2O5. At pH > 11-12 the equilibrium solid do not contain Ak(VUO6)k*nH2O and consist of the Ak(OH)2 and Na2U2O7 mixture. The solubility products were calculated using the solubility data of the system for the pH intervals, where uranyl vanadates saved their composition and structure. The type of interlayer atom do not significant influence on the solubility of compounds. The solubility of Ak(VUO6)k*nH2O has been determined, it changes on the several orders from 10-6 – 10-8М in the subalkali solutions to 10-2 - 10-3M in the acid and the strongly alkaline media. It was established that the solubility products values for all investigated compounds decrease according to the interlayer atoms radius increasing. The solubility products allow to calculate the thermodynamic functions of the heterogeneous system components, to plot speciation diagrams of uranium (VI) and vanadium (V) in the aqueous solution and solid phases. The solid phase and aqueous solutions diagrams and solubility curves of uranyl vanadates at the range pH 0-14 were plotted. This research makes it possible to use experimental data to solve practical problems, and allows to obtain the important information about the state of the saturated aqueous solutions and the secondary phases of studied heterogeneous systems in the isobaric-isothermal conditions.
Speaker: Ms Anna Eremina (Alekseevna)
• 154
Theoretical Chemistry Study of Uranyl (VI)-Sulphate complex species
This theoretical study of several possible complex species of the general formula ([UO$_2$(H$_2$O)$_a$($\eta^1$-SO$_4$)$_b$($\eta^2$-SO$_4$)$_c$]$^{2-2(b+c)}, 0 ≤ b + c ≤ 4, 5 ≤ a + b + 2c ≤ 6, [UO$_2$(H$_2$O)$_2$($\eta^1$-SO$_4$)($\eta^2$-SO$_4$)]$^{2-}$depicted at the Fig. 1.) aspires to the theoretical prediction of stability constants$\beta$°, thermodynamical properties (i.e.$\Delta$G° and$\Delta$H°) and their dependance on the temperature. Equilibrium geometries in the ground state and several excited electronic states, vibrational modes and frequencies, moments of inertia, vertical transition energies important to the UV-VIS absorption, excitation and emission/fluorescence spectra were calculated as well. Our study is also the first step towards the molecular-dynamical study searching seeking for another approach to predict$\Delta$G°,$\Delta$H° and log$\beta\$° and, more importantly, to predict the fluorescence lifetimes (or more generaly - the TRLFS spectra) and their dependance on the temperature and ionic strength (or, more generaly - the solution composition). The comparison of all of the ab initio predicted and experimentally obtained quantities is included. Both, the purely ab initio methods based on the Dirac(-Breit) equation (DHF, MCDHF, KRCI, CCSD) and the density functional methods (DFT (b3-lyp/def-SVP), TDDFT (bh-lyp/def-SVP)) were used. This work tries to reproduce and further develop the study of uranyl-sulfates done by Jakub Šebera [1].
Speaker: Mr Jakub Visnak (Department of Nuclear Chemistry, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague)
• 155
UO2, NpO2 and PuO2 preparation in aqueous nitrate solutions in the presence of hydrazine hydrate
Modern nuclear power engineering is focused on the use of fast neutron reactors (FNR). These reactors run on the mixed uranium-plutonium oxide fuel (MOX) and allow one both to use weapon-grade plutonium as a fuel and to transmute formed long-lived actinide isotopes. In this connection there arises the problem of a creation of economically effective and environmentally acceptable technology of the MOX fuel production. The separation technologies of U and Pu from spent nuclear fuel (SNF) complete nitrates forms of these elements. As a rule, uranium and plutonium are isolated from the solutions by ammonia and oxalate precipitation, respectively. Isolated compounds are used for the production of powders of uranium and plutonium dioxides or nitrides for MOX fuel synthesis. For example powders of the mixed oxides are produced by precipitation from the solutions of mixtures of ammonium diuranate and plutonium hydroxide or by combined co-precipitation ammonium uranylplutonyl carbonates followed by filtration, drying and ignition of the compounds obtained at 800 °C under reducing conditions of argon-hydrogen atmosphere. The disadvantages are obvious - the complexity of the implementation and the multi-stage processes. The development of new technologies for MOX fuel involves fixing the problem of denitration of actinides aqueous solutions. There exist the methods of direct denitration and by using reagents. Gaseous hydrogen, formaldehyde, formic acid, urea, sugar, ethyl alcohol et al. are used in the methods of reagent denitration. This work presents data on thermal denitration of U, Np, Pu solutions by hydrazine hydrate to produce individual and mixed oxides of these elements. Simple and effective method of preparation of homogeneously mixed U, Np and Pu dioxides from aqueous nitrate solutions containing a mixture of the actinides was developed. The method is to use a thermal denitration of solutions of U, Np and Pu nitrates in the presence of hydrazine hydrate to obtain hydrated dioxides of these elements. It was established that the UO2xnH2O calcination results: • crystalline UO2 under inert or reducing conditions in the range of 280-800 °C; • UO3 in air atmosphere at 440 °C; • U3O8 at 570-800 °С. It was shown that thermolysis of the solution containing a mixture of uranium, neptunium and plutonium nitrates at 90 °C in the presence of hydrazine hydrate allows one to prepare hydrated dioxides (U, Np, Pu)O2xnH2O which on heating to ~300 °C transmogrify into crystalline (U, Np, Pu)O2 solid solution.
Speaker: Dr Sergey Vinokurov (Vernadsky Institute RAS)
• Poster Session - Radiation Chemistry
• 156
Approach of evaluation of influence of gamma and UV radiation on microorganisms in presence of some scavengers of OH radicals.
During irradiation of microorganisms in liquid media by gamma radiation, hydroxyl radicals are considered as one of the most dangerous agents. Elimination of these radicals by their scavengers (ethanol, methanol and potassium formate) should protect the cells. Comparison of two ways of interpretation of acquired data was performed. Dependencies of σ ( =(ln⁡(s0))/(ln⁡(s)), where s0 is fraction of cells surviving in suspension with no scavenger added and s is fraction of cells surviving in suspension with one of OH scavengers) and α (increase of survival) on scavenging efficiency (Q) were evaluated and compared. Besides, a method that allows to compare effects of gamma and UV radiation was developed. This procedure, permitting to determine the dose of UV light, is based on constant absorbance and continuous stirring of the sample during irradiation.
Speaker: Mr Jaroslav Červenák (CTU)
• 157
Chemical evolution studies: The radiation chemistry and thermal decomposition of malonic acid
A cornerstone of modern biology is Darwinian evolution. By accepting the Darwinian evolution, we must postulate another form of evolution before this, and it is called chemical evolution. Thus, chemical evolution encompasses the study of physical and chemical events leading the formation of biological relevant molecules for the probiotic milieu. This process is considered a necessity for the emergence of recognizable living forms. Early Earth was extremely dynamic and chemically complex because the existence of different environments (atmosphere, lithosphere and hydrosphere, and the interfaces among them) where chemical evolution proceeded complicating the scenario. For the chemical processes a source of energy was also necessary. Several sources of energy have been proposed to contribute for the chemical evolution; among them are high-energy radiation and thermal energy. Several environments on Earth have temperature gradients. These gradients chemical reactions, for example, in volcanic hot springs, and especially in hydrothermal vents on the bottom of the ocean (some at moderately high temperatures). In these environments, the presence of radionuclides was also important for the synthesis or degradation of the present chemical compounds. Thus, radioactivity must be important because it has been present since the formation of the planet. During the supernova explosion, many of the chemical elements were synthesized, many of them with radioactive nature, allowing the synthesis /decomposition of organic molecules. In this context, the radiolysis and thermolysis of malonic acid in aqueous solution has been studied. The importance of this compound is because it might play a dual role as intermediate in the synthesis of other polycarboxylic acids and inhibiting important metabolic processes such as the Kreb's cycle. In our experiments, malonic acid was irradiated with gamma rays in oxygen-free aqueous solutions. The thermal decomposition was studied in a static system at temperatures from room temperature up to 90 °C simulating a hydrothermal vent. The main products obtained by the thermal treatment were acetic acid and CO2. The radiolysis of malonic acid yields carbon dioxide, acetic acid and di and tricarboxylic acids such as succinic, carboxy- succinic tricarballylic and citric acids. A numerical simulation of the chemical process taking place under irradiation was developed and it was being able to reproduce the time evolution of the products of irradiation and the consumption of the malonic acid. Finding these compounds are very important in chemical evolution studies as they are the source of the important building blocks of metabolic pathways. We experimentally identified the products by gas chromatography, and gas chromatography coupled to mass spectroscopy. This work was supported by PAPIIT Grant No. IN110712 and the CONACyT Grant No. 168579/11. One of us (JC) was supported by CONACYT grant. The support of Programa de Doctorado en Ciencias Quimicas is acknowledged.
Speaker: Dr Alicia Negron-Mendoza (Instituto de Ciencias Nucleares, UNAM)
• 158
COMPUTER SIMULATION OF DIFFUSION, ADSORPTION, DESORPTION, AND β - DECAY OF 89Br ON THE TUNGSTEN SURFACE
In course of construction of thermionic converter it is necessary to solve the problem of electrodes metal surface [1]. This paper presents the method and results of computer simulation of surface diffusion, adsorption, desorption, and β-decay of 89Br on the surface of single-crystal tungsten, in both case at the presence, and at the absence of 133Cs on it. The simulation of all the mentioned processes was carried out by solving the system of partial differential equation with the appropriate boundary and initial conditions. As a result of this simulation it was shown that: - principal amount of 89Sr hits the surface of the tungsten collector by direct adsorption from the gas phase and not at the expense of β-decay of 88Kr, 89Kr, 89Rb, 89mY and 89Y in the adsorption layer. - joint diffusion and desorption of 89Sr with the presence on the surface of 133Cs is faster than a single 89Sr. Literature 1 D.Yu. Lyubimov, I.I. Fedik, A.A. Shumilov, “Effet of fission products on the output power of thermionic EGC with communicating and separated fuel-element cavities and in interelectrode gap”, Atomic Energy, 2011, Vol. 110, № 6, p. 395-404. 2 Ya.E. Geguzin,“Diffusion by real crystal surface” in Surface diffusion and…, Nauka, Moscow, 1969, p. 11-77. 3 R.Ya. Kucherov, D.Yu. Lyubimov, L.G. Smirnov, et al., “Modeling physicochemical processes on the surface of niobium-oxygen collector in a thermionic”, Materialovedenie, 2002, № 7, p. 11-17.
Speaker: Mr Andrei Androsov (russian)
• 159
Containment surface interactions of gaseous elemental iodine and ruthenium tetroxide during severe nuclear accidents in LWRs
During severe nuclear accidents in LWRs several hazardous and radiotoxic gaseous fission products will be released from damaged UO2 fuel. Volatile iodine species (CsI, IOx, I2, org. iodides such as MeI) will be released and formed already in an early stage of a severe accident, while the release of volatile oxides of ruthenium (RuO3, RuO4) will require a rupture of the containment with a significant air ingress. Considerable amounts of released CsI and elemental iodine will dissolve in the water pools and steam. Remaining gaseous elemental iodine can be partly immobilized by sorption on the containment surface and structural materials (paint, Al, Cu, Zn). A fraction of the iodine will be physisorbed and thus can be rather quickly revaporised or washed off from the surfaces. Some of the iodine will be chemisorbed, like on copper and epoxy paint surfaces (Teknopox Aqua VA). Ruthenium tetroxide has a high affinity to deposit on all the available surface materials. It is a strong oxidizing agent and thus possibly affects the volatile iodine source term. Differences of the sorption behavior of RuO4 on plane and iodine covered surfaces have been investigated qualitatively and quantitatively, as well as the effects on the iodine revaporisation behavior.
Speaker: Mr Ivan Kajan (Chalmers University of Technology)
• 160
Natural metamict minerals as analogues of aged nuclear ceramic waste forms
Natural metamict U-Th-containing minerals are well known analogues of aged nuclear ceramic waste forms, which were affected by self-irradiation and chemical alteration under the conditions of geological environment. Main concern related to the behavior of radioactive ceramics during their long-term storage is the stability of radionuclide solid solution in the crystalline structure of durable host-phases. Self-irradiation may cause not only damage of crystalline structure of host-phase (its amorphization or metamictization) but also destruction of solid-solution and release of radionuclides in separate chemically mobile forms. We have studied two large (1-3 cm in size) and relatively homogeneous samples of natural fully metamict minerals: Y-Fe-niobate, (Y,Fe,U,Th)x(Nb,Ti,Ta)yOz (containing 1.0 wt.% ThO2 and 4.2 wt.% UO2) and lovchorrite, Na(Ca,Na)2(Ca,Ce)4TiO2F2(Si2О7)2 (containing 1.1 wt.% ThO2). No evidences of solid solution destruction as a result of metamictization were observed in these samples. Both samples: untreated and annealed at different temperatures in order to initiate recrystallization were analyzed in comparison by precise X-ray powder diffraction, electron microprobe (EMPA) and scanning electron spectroscopy (SEM). It was observed that annealing caused not only recrystallization of both samples but also destruction of initially homogeneous solid solutions with partial release of U or Th in the forms of separate phases. It was proposed that recrystallization of aged nuclear ceramic waste forms as a result of any possible natural process is not positive phenomenon as it was assumed before. Recovery of crystalline structure can be accompanied by essential release of radionuclides.
Speaker: Mrs Qiuxiang Cao (East China Institute of Technology, Guanglan Road, 418, 330013, Nanchang, Jiangxi, China;Saint-Petersburg State University, Universitetskaya emb. 7/9, 199034, St.-Petersburg, Russia)
• 161
Radiation Stability of CyMe<sub>4</sub>-BTBP and CyMe<sub>4</sub>-BTPhen in their Solutions in Cyclohexanone-based Diluents
Speaker: Jana Sočuvková (CTU in Prague, FNSPE, Department of Nuclear Chemistry, Prague)
• 162
Radiation Stability of Hydrocarbon Diluents of TBP in Two Phase System Used in SNF Reprocessing
The modern technology of reprocessing of irradiated fuel nuclear power plants (NPP SNF) is based on the Purex process, which uses a solution of tributylphosphate (TBP) in an inert dilu-ent as extractant. There are most commonly used aliphatic hydrocarbons with straight chain and mixtures thereof (a mixture of n-paraffins) or mixtures of iso-paraffins (tetrapropylene) or a mixture of n-paraffins with iso-paraffins and naphthenes (dearomatised kerosene). High ra-diation and chemical exposure faced by the extractant lead to the formation and accumulation of impurities, which affect its hydrodynamic and selective properties. Therefore the extractant is constantly regenerated in the extraction cycle by soda washing but a part of the degradation products is not removed by this treatment and gradually accumulates. The basic role in dete-rioration of hydrodynamical characteristics of the extractant is played by the products of ra-diation-chemical decomposition of hydrocarbon diluents among which the main contribution is from the products of nitration, oxidations and the mixed products of interaction with TBF. The purpose of the given work is comparison of radiation stability of branched diluent Isopar-M, mixtures of i-paraffins С13 (C11- 7,11 %, С12 - 17,25%, С13 - 72,15%, С14 and above - less 2.9 %) and comparison to data on destructions of RED-1, and also substantiation of choice of both high boiling diluent, and the recycling solution allowing to wash away organic ligands and admixed elements from the extractant thus not creating difficultly separable emul-sions and deposits, formed, first of all, by sodium salts VKK. After each cycle of irradiation a reextraction was performed, an organic phase was halved: one half was recycled with Na2CO3, and another half was recycled with NaHCO3 for com-parison. After each contact the speed of aliquation and after each cycle in both variants the size of an interphase tension were determined. The latter was determined by modified Re-binder's device by method of detection of the maximal pressure in a bubble of an organic phase. Comparing data on an irradiation of studied diluents with investigated earlier RED-1 and RJ-13, it could be noted, that a superficial tension on soda regeneration at irradiated С13 and Isopar-M is a little bit higher, than at irradiated RED-1 and RJ-13. Thus speeds of aliquation of emulsions at soda processing at С13 and Isopar-M have close values and since a doze of an irradiation of 200 kGy practically does not change up to a doze 500 kGy, keeping value within the limits of 0,2-0,3 of mm/s while for RJ-13 speed of aliquation monotonously de-creases and at a doze 550 kGy is 0,1 mm/s, and RED-1 at dozes more 200 kGy does not un-dergo aliquation. Thus, newly examined diluents are characterized by more stable properties at an irradiation in comparison with studied earlier. Thus, Isopar-M has appreciable advantage over С13 at the stage of regeneration, especially at use of 1 M solution of NaHCO3 increasing in the irradiation process. For a choice of a spe-cific diluent for radiochemical plant it is necessary to consider both individual dissolving abil-ity, including propensity of formation of the 2nd organic phase, and specificity of production.
Speaker: Dr Elena Belova (Russian academy of sciences A.N. Frumkin Institute of Physical chemistry and Electrochemistry RAS)
• 163
Radiolysis of Frozen Aqueous Solution of Methanol
Comets contain a silicate core, an organic refractory inner mantle and an outer mantle, predominantly of water ices in which are embedded small particles. The spectroscopic analyses suggest the presence of molecules, such as ammonia (NH3), methane (CH4), formaldehyde (H2CO), methanol (CH3OH) and hydrogen cyanide (HCN). The possibility that comets collide with planets delivering such compounds made those bodies very attractive, connecting them with chemical evolution and the origin of life on Earth. Comets, since their formation, have been exposed, besides ultraviolet radiation, to high levels of ionizing radiation due to cosmic rays and decays of imbedded radionuclei. The bombardment by energetic particles profoundly affects the nuclei composition, and new chemical species are produced by radiolysis. Therefore, the radiation-induced reactions are very important when consider the evolution of the cometary material. The estimate of the total absorbed dose accumulated -from the internal radionuclides and external radiation- over a comet life-time is nearly 3000 MGy at the surface. For that reason, radiation chemistry can be a very precise and useful tool to simulate the evolution of organic molecules exposed to high-energy radiation during the life-time of a comet. In this work, we analyzed the results on irradiated frozen dilute solutions of methanol, as one of the components of a nucleus comet. As a result of the radiolysis at 77 K, the active radical species form the dimeric product, glycol. The irradiation was carried out in a 60-cobalt gamma source and the irradiation doses were from 2.5 kGy to 3000 kGy. This work was supported by PAPIIT Grant No. IN110513 and the CONACyT Grant No. 168579/11. The technical assistance from C. Camargo, B. Leal, and F. García-Flores is acknowledged.
Speaker: Prof. Sergio Ramos-Bernal (Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico)
• 164
Redox Behavior of Neptunium in Irradiated Aqueous Solutions of Nitric Acid in Presence of an Extracting Organic Phase
A reliable solvent extraction process for separation of neptunium from irradiated nuclear fuels depends upon the maintenance of a valence state amenable to complexation by tributylphosphate (TBP). However, radiolytic generation of nitrous acid in irradiated nitric acid solution may reduce extractable Np(VI) into non-extractable Np(V). One complicating factor that has so far not been well investigated is the influence of the presence of an extracting organic phase on the redox speciation and extraction of neptunium during radiolysis; hence, the rates and total yields of radiolytic reduction of neptunium were measured in varying concentrations of nitric acid, both in the presence and absence of a 30% TBP/dodecane organic phase. In the aqueous solution, greater concentrations of nitrous acid were produced at higher nitric acid, although this did not necessarily result in faster reduction rates for Np(VI). This is likely because of oxidation of Np(V) directly by nitric acid and by oxidizing radicals produced by radiolysis of aqueous nitric acid. The presence of the organic phase appeared to protect Np(VI) from reduction, perhaps due to complexation by TBP.
Speaker: Dr Martin Precek (Institute of Physics AS CR)
• 165
Stability Under Irradiation of Some Aminoacids
Homochirality of certain organic molecules essential for all living organisms, such as the L-amino acids and the D-sugars, has made the search for its origin an important issue in studies of the origin of life and evolution. Comets and asteroids are thought to include organic compounds imbibed in ices, rocks, and have been proposed as carrier of those compounds to the early Earth. Among the products detected in meteorites (carbonaceus condrites)are amino acids, which are key compounds for chemical evolution studies. The meteoritic amino acids are of the D and L optical isomers types with a lightly enantiomeric excess. The mechanism involved for this excess is still a debate. One theory involves the irradiation with high energy on racemic mixtures. The purpose of this work is to study the stability under irradiation of some amino acids (in solid state and in aqueous solutions). For this purpose, individual amino acids (L, D and D,L alanine, L, D and D,L serine and L, D and D,L phenylalanine) were exposed to different irradiation doses up to 90 MGy that is a dose higher than the calculated total dose that received a comet since it formation. The analysis of the samples was made by high performance liquid chromatography with a quiral column. The results show that the molecules under study presented great stability under gamma irradiation and the recovery is more than 60%. The support from CONACYT grant No.16857911 , PAPIIT grant IN110513 and Posgrado en Ciencias Quimicas is acknowledged. One of us (EA) was supported by a CONACYT fellowship.
Speaker: Dr Alicia Negron-Mendoza (Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico (UNAM))
• 166
Thiacalix[4]arenes: radiation stability and Eu/Am extraction in synergistic systems with COSANs
This study deals with the effects of irradiation on the stability and extraction properties of thiacalixarenes1, the prospective liquid-liquid extractants for the extraction of actinides and lanthanides from aqueous solutions. Thiacalixarenes (T1, T2) dissolved in cyclohexanone and 1,2-dichloroethane were irradiated with 60Co gamma rays or accelerated electrons with energy of 4.5 MeV. The absorbed doses ranged from 0 to 100 kGy. The extraction properties towards europium and americium, as lanthanide and actinide representatives, were studied in synergistic systems. The combinations of two thiacalixarene extracting agents, three COSAN molecules and three diluents (chlorobenzene, nitrobenzene and 1,2-dichloroethane) were evaluated. For the determination of residual concentration, the HPLC method was used and compared with the assessment of the change of the D(Am) and D(Eu) values in solvent extraction experiments. The aqueous phase consisted of a solution of COSAN (chloro-protected bis(1,2-dicarbollide) cobaltic acid) in 0.1mol/l nitric acid; solutions of thiacalixarene T2 in 1,2-dichlorethane were used as the organic phase. Distribution ratios D for 152Eu and 241Am and their mutual separation factors were evaluated. The activity of aqueous and organic phase was measured via gamma spectrometer with HPGe detector. The results obtained from both methods correspond to each other and the decline in the extraction behaviour can be derived from the residual concentration determination and otherwise. Both thiacalixarenes seem to be more stable in the irradiated cyclohexanone samples than in the 1,2-dichloroethane samples which is in good agreement with the state that during cyclohexanone radiolysis less aggressive intermediates are produced comparing with the latter case. This work was performed under the auspices of Czech Science Foundation grant GACR 104-07-1242 and Ministry of the Interior of the Czech Republic grant VG20132015132. REFERENCES 1. Lhoták P.: Eur. J. Org. Chem., 2004(8), 1675.
Speaker: Irena Špendlíková (KJCH FJFI CVUT)
• 167
Time programming of mechanical and electronic properties of materials via self-irradiation phenomena : a theoretical study.
Structure transformations owing to self-irradiation of materials by fission products of unstable isotopes constitute a special case of ageing phenomena. For instance, radio-decay of uranium and thorium atoms substituting zirconium atoms in the crystal lattice of zircon causes radiation damage and gradual amorphization of the mineral’s structure. This process called metamictization leads to negating of birefringence, lowering of the mineral’s refractive index, hardness and specific gravity. In our work, we consider theoretically intentional induction of ageing processes in materials via the introduction of small quantities of unstable nuclei in materials structure. It is argued that both mechanical and electronic properties of materials can be programmed over relatively large time intervals by the use of radioisotopes. The approach can open the route to novel materials with time-dependent functionalities. For example, radio-decay of unstable nuclei embedded in conductive polymers and dielectrics will enable the design of electrical resistors and capacitors with well-defined time-dependent characteristics. Such electronic elements can be explored for creation of electronic circuits which self-activate or self-desactivate after a certain time interval. Incorporation of minuscule amounts of radio-active species (e.g. carbon-14, tritium) in the structure of polymers, such as polytetrafluoroethylene, can be investigated for presetting self-decomposition of plastic products to a certain term. Relaxation of internal mechanical stresses, amorphization and swelling driven by self-irradiation can be used for programming the configurations of mechanical systems (e.g. bending/unbending of bimetal films) over large terms. Possible implementations of the time-programmed materials and their perspective applications are discussed, as well as the radiation safety concerns and the choice of suitable radio-isotopes. V. Luchnikov, J Mater Sci (2009) 44:6294–6301
Speaker: Dr Valeriy Luchnikov (Institut de Science des Matériaux de Mulhouse CNRS)

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• 168
129I in the Antarctic seawater measured by carrier free iodine separation and AMS
Due to low concentration of iodine in seawater, iodine carrier is normally added as carrier for separation of 129I from matrix using solvent extraction, this is not suitable for the determination of low level 129I in the seawater received less anthropogenic 129I such as those collected in south hemisphere including the Antarctic and deep seas, because of contribution of 129I in the iodine carrier to the sample during sample preparation. A simple co-precipitation method for separation of carrier free iodine from seawater for measurement of 129I/127I using accelerator mass spectrometry (AMS) has been reported by our group. In this work, some improvement of this method was completed to able to obtain better measurement uncertainty in AMS measurement. The results reveal that addition of small amount of carrier (0.1-0.2 mg) can significantly improve the measurement accuracy and precision. A certified seawater reference material, IAEA-418 (Mediterranean Sea water) has been successfully analyzed by utilizing the presented method and the concentration of 129I was measured to be 2.36×108 atoms L-1 in this sample, which agreed well with the certified value (2.28×108 atoms L-1), as well as the results measured by traditional solvent extraction by addition of 2 mg iodine carrier, indicating reliability of the developed method. Six seawater samples collected from the Antarctic in 2011 were analyzed utilizing the developed method. The results indicate that 129I/127I atomic ratios in the investigated area range from 0.7×10-12~9.9×10-12 with a mean of 6.1×10-12, which is close or slightly higher than the reported pre-anthropogenic ratio of 1.5×10-12. The main source of 129I in the investigated area might be attributed to the global fallout of both atmospheric nuclear weapons testing and long distance dispersion of fuel reprocessing releases. This is the first report of 129I in the seawater from the Antarctic, the results shed a light of feasible application of 129I as an oceanographic tracer application of 129I the Antarctic.
Speakers: Prof. Aldahan Ala (1) Uppsala University; 2) United Arab Emirates University), Prof. Hou Xiaolin (1) Institute of Earth Environment, CAS; 2)Technical University of Denmark), Mr Xing Shan (Institute of Earth Environment, CAS)
• 169
210Po and 210Pb in fur of domestic animals
The aim of the study was to determine 210Po and 210Pb in fur samples collected from 15 breeds of dogs Canis familiaris living in the northern Poland. The average values of analyzed radionuclides in analyzed dog fur ranged from 0.46±0.02 mBq∙g-1 to 15.05±1.13 mBq∙g-1 for 210Po and from 0.31±0.03 mBq∙g-1 to 9.82±0.53 mBq∙g-1 for 210Pb. The highest activities of 210Po and 210Pb were measured for small long-haired dog Maltese while the lowest in small long-haired Yorkshire terrier and Poodle toy. The values of the 210Po/210Pb activity ratio were calculated from 0.82±0.09 for Yorkshire terrier to 5.16±0.45 for Bolognese. Generally, both 210Po and 210Pb radioisotopes accumulation did not depend on dog sex. Higher values of 210Po and 210Pb were found in long and rough-haired dogs. Further, our experiments showed the hair from dogs living in villages contained more 210Pb than dogs living in the cities and dogs eating dry food accumulate more 210Po in their hair in comparison to fresh or mixed food eating dogs. The authors would like to thank the Ministry of Sciences and Higher Education for the financial support of this work under grant DS/530-8120-D384-14.
Speaker: Ms Karolina Szymanska (Faculty of Chemistry, University of Gdansk)
• 170
210Ро in Different Types of Teas
As to their biological effect, 210Pb and 210Ро - radionuclides are in a group of the most toxic ones. 210Pb and its daughter products are mainly formed in the atmosphere following alpha-decay of 222Rn. Then, together with dry and wet depositions, these products are precipitated on the soil surface and plant leaves, the latter being known as a plant part with an enhanced content of 210Ро [1]. As teas are globally the second only to drinking water as regards the volume consumed, the determination of 210Ро in teas is an actual problem. The aim of the present work is to determine specific activity of 210Ро in different types of teas (black and green ones) and to estimate the effective annual radiation dose due to alpha-particles of 210Ро that enters the human organism when drinking tea. The content of 210Ро in samples and aqueous extracts thereof was determined by alpha-spectrometry. The aqueous extracts were obtained by brewing 10 g of tea in 200 mL of boiling water for 10 minutes. The effective annual radiation dose was calculated assuming that the daily consumption was 10 g of dry tea. Experimental results and calculations are presented below. Sample and country of origin; Specific radioactivity of 210Po,Bk/ kg; Fraction of extracted 210Po,%; Effective annual radiation dose due to 210Po, µSv/yr Black Teas 1.Princess Nuri (India); 7.3±1.4; 17%; 5 2.Krasnodar (Russia); 12.7±3.5; 1.5%; 1 3.Lisma (Ceylon); 16.7±4.6; 4%; 2 4.Talk (India); 24.5±4.8; 4%; 3 Mean 15.3±5.0; 6.6%; 3 Green Teas 5.Bird Ceylon Tea; 1.0±0.3; 11%; 1 6.Jaf Tea (Ceylon); 3.2±0.8; 55%; 9 7.Bird of Paradise; 3.5±1.0; 18%; 3 8.Princess Java (China); 24.4±4.2; 13%; 9 Mean 8.0±3.0; 24.3%; 6 Variations of 210Ро specific radioactivities in the samples under study may be attributed to varying 222Rn concentrations in the surface air and different soil properties of the tea gardens. The mean 210Ро concentration in the samples of black tea is approximately two times that of in the samples of green tea, a possible reason for this being specific processing technologies for different types of tea. The raw material used for making green tea is treated with steam at temperatures from 95 to 100 C [2], the weakly bounded Polonium species (e.g., those of in dust particles) being taken off the tea-leaf surface. When making black teas, there is no stage of steam treatment and 210Ро is not removed from the tea leaves. When making green tea in China, instead of steam treatment it is another procedure that is used, that of roasting the raw material at temperatures from 65 – 75 С [2]. It cannot result in the removal of 210Ро from the leaf surface, and in the “Princess Java” green tea produced in China there are more radionuclide than there is in teas from Ceylon. Green tea aqueous extracts are known to contain more organic substances than those ones from black teas [2]. The higher 210Ро content in extracts from green teas might be an indirect indication of a change of the physico-chemical state of the radionuclide during the stage of processing the tea raw material. It is possible that a certain part of the radionuclide transforms from the initial inorganic species into an organic one. On drinking green teas, the maximum effective annual dose due to 210Ро, which is equal to 9 µSv/yr, is comparable to the total annual dose due to 210Pb, 210Po, 228Rа, and 226Rа nuclides acquired from drinking water and is estimated to be 10 µSv/yr [3]. 1.Parfenov Y. D. Po-210 in the Environment and in the Human Organism. Atomic Energy Reviews, v. 12, 1974, p. 75 – 143. 2.Semenov V. М. The Newest Encyclopedia of Teas. Moscow, Nauka, 2006 (in Russian). 3.Commentaries to Radiation Security Norms (NRB-99-2009).Мoscow, 2009 (in Russian).
Speaker: Dr Natalia Gomzina (N.P.Bekhtereva Institute of the Human Brain, Russian Academy of Sciences (IHB RAS), St. Petersburg, Russia)
• 171
241Pu in seabirds
The paper presents unique data of plutonium 241Pu study in seabirds from northern Eurasia, permanently or temporally living at the southern Baltic Sea coast. Together 10 marine birds species were examined: 3 species of permanently residing at the southern Baltic, 4 species of wintering birds and 3 species of migrating birds; about 150 samples were analyzed. The obtained results indicated plutonium is non-uniformly distributed in organs and tissues of analyzed seabirds. Generally the highest plutonium concentrations were found in the digestion organs and feathers, next in skeleton, and the lowest in muscles. Among analyzed birds the highest 241Pu concentration was found in viscera, its activities in the digestive organs ranged from 9.7±2.5 µBqg-1 ww (13.0% of total 241Pu) in great cormorant (P. carbo) to 228±39 µBqg-1 ww (79.6% of total 241Pu) in velvet scoter (M. fusca). High 241Pu concentrations were also found in liver where ranged from 21±4 µBqg-1 ww in velvet scoter (M. fusca) (2.2% of total 241Pu) to 159±31 µBqg-1 ww in tufted duck (A. fuligula) and feathers where ranged from 15±4 µBqg-1 ww in great cormorant (P. carbo) (11.6% of total 241Pu) to 132±59 µBqg-1 ww (34.2% of total 241Pu) in common eider (S. mollissima). The main source of plutonium in analyzed marine birds was global atmospheric fallout as well as the Chernobyl accident, which was confirmed by plutonium activity ratios of 241Pu/239+240Pu as well as 238Pu/239+240Pu. On the basis of the average 241Pu concentrations in the southern Baltic Sea biocenosis components the plutonium content in marine organisms increases as: seabirds < fish < phytobenthos < phytoplankton < zooplankton < zoobenthos. The authors would like to thank the Ministry of Sciences and Higher Education for the financial support of this work under grant DS/530-8120-D384-14.
Speaker: Ms Karolina Szymanska (Faculty of Chemistry, University of Gdansk)
• 172
241Pu in the southern Baltic Sea ecosystem
Most contamination studies have focused on alpha emitting plutonium isotopes so far. 241Pu is less important in terms of its radiotoxicity than the α-emitting plutonium radionuclides 238,239,240Pu but is quite significant because of its huge contribution to the whole plutonium fallout. Our previous experiments on air samples indicated extreme increase of 241Pu amount in atmospheric dust in April 1986. The available information about the bioaccumulation and distribution of 241Pu in the Baltic Sea ecosystem and Poland territory is still very limited. The main purpose of the present work was to complete the present knowledge and estimate the further levels of the Baltic Sea environment contamination. The highest total 241Pu concentration in seawater was found in the Słupsk Bank (3.35±0.17 mBq∙dm-3) and this area had the highest concentration of 241Pu connected to suspended matter as well (1.94±0.12 mBq∙dm-3). High concentrations of 241Pu in the central part of the southern Baltic Sea can be a result of Baltic water circulation. The 241Pu activity in phytoplankton sample from the Pomeranian Bay was 1.06±0.09 mBq∙g-1 dw. Within zooplankton samples the highest 241Pu activity was found in samples from the central part of the southern Baltic (2.66±0.16 mBq∙g-1 dw) and from the Gdańsk Deep (2.64±0.70 mBq∙g-1 dw). In zooplankton samples, similar situation to seawater samples was noticed – the highest concentrations of 241Pu were found in the central part of the southern Baltic Sea, and similarly to seawater it could be a result of Baltic water circulation. Generally the data show significant differences in 241Pu concentrations among all the species examined. The highest values of 241Pu activities for whole organism were found in fish from Perciformes: benthic round goby (0.863±0.066 mBq∙g-1 ww) and pelagic perch (0.666±0.001 mBq∙g-1 ww). The lowest 241Pu activity was found in flounder (0.104±0.009 mBq∙g-1 ww). The plutonium was also non-uniformly distributed between the organs and tissues of the analyzed fish, especially pelagic herring and cod as well as benthic flounder. In sediments, the highest amount of plutonium was found in the middle parts of all analyzed sediments and came from the global atmospheric fallout from nuclear tests in 1958-61. The distribution of 241Pu in analyzed sediments samples was not uniform and depended on the sediment geomorphology and depth as well as on its location. The authors would like to thank the Ministry of Sciences and Higher Education for the financial support of this work under grant DS/530-8120-D384-14.
Speaker: Ms Karolina Szymanska (Faculty of Chemistry, University of Gdansk)
• 173
Activity of 210Po in the blood and urine of the residents of the Tricity agglomeration
The natural radionuclide polonium is daughter of 238U decay series. 210Po is radionuclide with half-lives of 138.38 days. Polonium is one of the most radiotoxic natural radioactive isotopes to man due to its high speciﬁc activity and its emission of high-LET alpha radiation. Less than 0.05 g of the radionuclide is considered a lethal dose (LD50/30). Man is exposed to radioactive 210Po by natural processes, mainly from the oral intake of foodstuff and drinking water. Especially large amounts of polonium are taken in during cigarette smoking as well as food of marine products. The large amounts of polonium are observed in protein-rich food, such as shellﬁsh and crustaceans, and also observed among populations consuming large amount of reindeer and caribou meat, e. g. in Subarctic area. The aim of this study was to establish the polonium 210Po concentrations in blood samples and urine. Healthy urine and blood are not toxic. However, there contains compounds eliminated by the body as undesirable. The tested group constituted patients from Medical University of Gdansk and volunteers from Tricity aglomeration. Eating ﬁsh and cigarette smoking are factors that according to many researchers affects the amount of this radionuclide in the human body. The questions about smoking and frequency of ﬁsh eating were included in questionnaire for the patients and volunteers. This is very important because human biomonitoring of 210Po has been conducted for a long time, but it is still not fully known and understood. The human blood samples about volume 10 ml were collected from 43 patients ischaemic heart disease (IHD) from Medical University of Gdansk. The reason for choosing this particular group was purely accidental. The urine samples were collected from 37 volunteers from Tricity agglomeration (Gdansk, Sopot, Gdynia). Urine samples were collected throughout the day. The daily amount of urine excreted by volunteers ranged from 600 to 3500 ml. The research was approved by the Independent Bioethics Committee for Scientiﬁc Research of the Medical University of Gdansk. The results of this work indicate that the activity of 210Po in human blood and urine was in the wide range between 140±14 mBq and 888±36 mBq in total blood without two patients (3072±270 mBq and 2901±245 mBq in total blood) and from 1.48±0.09 mBq to 19.41±0.81 mBq in urine samples respectively. The higher activity of this radionuclide was observed for smoker and ex-smoker groups. The patients and volunteers were subdivided in groups: males and females, cigarette smokers, non-smokers and ex-smokers were taken into account. The results indicated that the 210Po activity was widely distributed in the each group of analyzed patients and volunteers. The difference between 210Po activities in human blood and urine of ex-smokers/smokers and eating habits is statistically signiﬁcant. The obtained results of 210Po activity in the human blood and urine are probably related to the consumption of ﬁsh and smoking. Human sex and age had no effect on excretion of polonium from the urine during the day.
Speaker: Mr Grzegorz Romanczyk (University of Gdansk)
• 174
Adsorption of Trivalent Lanthanides and Actinides by Marine Sediments
Knowledge of the chemical behaviour of (radio)toxic elements in natural/environmental systems is of fundamental importance for the performance of environmental impact assessments and the application of protection measures after possible contamination. The interaction of actinides with marine sediments is of particular interest because marine sediments constitute the final receptors for the majority of actinides (Th, Am, Pu). In order to study the chemistry of trivalent actinides (e.g. Am(III), Cm(III)) often trivalent lanthanides are used as analogues, because lanthanides in aqueous solutions are generally stable in the trivalent oxidation state, present similar chemical behaviour as trivalent actinides, are non-radioactive and posses useful spectroscopic/fluorescent properties. In this study we have investigated the interaction of Nd(III) and Eu(III) with two different types of marine sediments as a function of various parameters (e.g. pH, [M(III)]o, I, tcontact) to evaluate their effect and get more information on the adsorption of Nd(III) and Eu(III) by marine sediments. Sorption of Eu(III) by marine sediments from aqueous solutions of varying pH 4 – 6.5, fixed ionic strength of 0.1 M (NaClO4) and at room temperature has been studied by fluorescence spectroscopy (LFS). In this context, the effect of the particle coating with natural organic matter (NOM, e.g humic acid) on the adsorption properties of the sediment samples has also been studied. According to the experimental results the adsorption of Nd(III) and Eu(III) ions by marine sediments is (a) a relatively fast process (b) the adsorption data are well described by the Langmuir isotherm and (c) the adsorption properties (e.g. adsorption capacity, pH and ionic strength effects) of the different sediment types differ significantly from one another, depending on the (surface) composition.
Speakers: Mrs Ioanna Liatsou (Chemistry Department, University of Cyprus), Mr Ioannis Pashalidis (Chemistry Department, University of Cyprus), Mrs Maria Efstathiou (Chemistry Department, University of Cyprus)
• 175
Chernobyl and other nuclear accidents have demonstrated that high levels of radiation can result in impacts on plants and animals, however little is known about the long-term effects of chronic exposure on biodiversity or other population and ecosystem level effects. The overall aim of this study is to assess the impacts of chronic exposure to radioactivity and chemical pollutants. The study area on the Eastern Black Sea Region, Turkey has metal mining (Fe, Au, Ag, Mn, Mo, Cu, Pb and Zn) and industrial facilities, having elevated levels of both heavy metals, and affected the fallout of radionuclides after Chernobyl. Results for radiation and chemical pollution were obtained from the analysis of soil samples taken from 6 sites. All soil samples were measured for gamma, beta and alpha activities. Also, elemental concentrations of soil samples were determined by instrumental neutron activation analysis and X-ray fluorescence analysis. In summary, to assess radiation and chemical pollution risk, the possible impact of long-term behaviour of the radionuclides and elements in soil should be taken into consideration. This type of study does however need to provide regional background levels for these important radioactive and chemical pollutants. Additional studies will be performed to estimate the exposure for the diversity and plants from radioactive and chemical pollutants.
Speaker: Ms Ruveyda Kubra ILERI (Istanbul Technical UniversiIstanbul Technical University, Energy Institutety, Energy Instıtute)
• 176
Biological Barrier for Nitrate Ions in Environments
A. Safonov, V. Ilin, V. Tregubova, T. Babich, E. Zakharova, T. Nazina Disposing of the nuclear industry wastes in Russia and the U.S.A. in the 20th century have led to significant amount of storages not equipped with appropriate effective/protective barrier systems. This pose risks of environmental pollution through dissipating harmful macrocomponents and radioactive nuclides. The basic RW macrocomponent are nitrate ions present at concentration levels from 10 to 350 g/dm3. These are rather toxic for ecosystem for the and are characterized by high migration level. The factor that can significantly impact to the migration profiles of nitrate and metals in the environment is the influence of biochemical processes. The purpose of this work is to create a barrier for the immobilization of nitrate ions in subterranian freshwater through the intensification of biochemical processes by organic matter around the artificial pond – surface repository B-2 with LRW at the Siberian Chemical Combine. It will be the part of the existing barrier system of the conserved repository B-2 at Siberian Chemical Combine. Nowadays there is new geochemical barrier based on silicate polymers in groundwater around the conserved repository. It can block main radionuclides with very high efficiency, but can’t slow-down the nitrate ion migration risk. The concentration of nitrates in groundwater around the conserved repository can crease up to 5000 mg per liter. The essence of the biobarrier method is to stimulate the vital processes of autochthonous (indigenous) microorganisms leading to the destruction of nitrate ions to ecologically safe molecular nitrogen by injecting to contaminated zone as organic substrates into groundwater around the repository. In laboratory conditions, indigenous bacteria of groundwater samples were proved to be able to decrease nitrate concentration from 3-5 g/l to 10-15 mg/l when were amended with acetate, sucrose, lactate, or glucose in concentration 1-5 g/l as electron donor and carbon source. These results are the scientific basis for the development of biobarrier technology. This biotechnology could improve the existing barrier system of repository B-2. The project was supported by grants: Russian Foundation for Basic Research (№ 13-04-92105 and 14-03-00067)
Speaker: Mr Alexey Safonov (Frumkin"s Institute of Physical Chemistry Russian Academy of Science)
• 177
Catalytic wet oxidation of metal ion complexing agents by H2O2 using homogeneous and heterogeneous Fe (III) species
A large amount of liquid radioactive wastes are formed during nuclear power plants operating. Radionuclides contained in the wastes are predominantly in the form of stable complexes with organic ligands, such as EDTA, citric and oxalic acids, which complicates the heavy metal separation. Concentrating and processing of liquid radioactive wastes can be greatly simplified after the removal of these organic compounds. Сatalytic wet oxidation of complexing agents by H2O2 using Fe (III) species is a promising way for radioactive waste purification. The presenting work considers a method of catalytic wet hydrogen peroxide oxidation (CWHPO) of EDTA using homogeneous and heterogeneous Fe(III) species. The solutions of mono- and polynuclear hydroxo complexes of Fe (III) have been obtained and studied as homogeneous catalytic systems. Several types of Fe (III) containing zeolites ZSM-5 with different particle morphology and texture, including nanozeolites and hierarchical zeolite, have been synthesized and tested as heterogeneous catalysts. The activity in CWHPO of different Fe (III) species was measured by barometric cell method and total organic content determination. In homogeneous 1 mM Fe (III) catalytic system the highest hydrogen peroxide decomposition rate was observed at pH = 2.5 when mononuclear Fe(III) hydroxo complexes were predominant. The reaction rate was found to be decreased at pH = 1.5 and 3.0 when hydrated and polynuclear hydroxo complexes were formed, respectively. At pH > 3 Fe (III) hydroxide precipitated and the reaction rate was negligibly low. Unlike homogeneous system zeolitic one allows proceeding the reaction at a significantly wider pH range. Heterogeneity of the Fe (III) catalytic sites in the zeolite appeared to result in effective use of the hydrogen peroxide and a deep oxidation of a substrate. A comparative study of stability and activity of Fe (III) species supported onto the zeolite and amorphous SiO2 has been made in oxidation of low and high molecular weight organic subtances by H2O2. Catalytic site protection by zeolitic matrix plays a key role in the reactions and could be potentially explored for development of technology for purification of waste water from nuclear power plants.
Speaker: Ms Vera Labko (Joint Institute for Power and Nuclear Research - SOSNY, National Academy of Sciences of Belarus)
• 178
Cesium-containing complex oxides of the pollucite structure. Synthesis, properties, preparation of ceramics with high relative density and its radiation tests
Complex oxides with the structure of the mineral pollucite (CsAlSi2O6) represent a large group of compounds and they are basic for the development of materials for different purposes, including immobilization of cesium from waste of radiochemical industries and preparation of medical sources radiation. The number of such oxides has increased significantly basing on isomorphism of atoms in the crystal lattice and calculations modeling compounds of phosphorus-containing phases [1]. Isomorphic substitution of aluminum by boron leads to the increase of cesium mass fraction and growth of the specific activity of the compound in the case of a radioactive isotope. Inclusion of boron in the phosphorus-containing pollucite-like phases provides new possibilities for the development of materials for nuclear medicine (boron neutron capture therapy, BNCT) and ceramics - neutron absorbers. Oxides with pollucite structure containing boron and aluminum Cs[MgR0.5P1.5O6], where R = B and Al, were synthesized using a sol-gel process, and they were characterized by X-Ray diffraction. Structural studies for obtained compounds were performed (Rietveld refinement). The thermal expansion was studied by using of the methods of high- and low-temperature X-Ray analysis at temperatures range from -100 to 800 °C (α = (7.3 - 8.6)·10-6 deg-1), thermal (tested up to 1200 °C) and hydrolytic stability (T = 90 °C, 1.46·10-5 g/(cm2•d)) were studied also. The obtained compounds were used for synthesis of the ceramics by spark plasma sintering. The relative densities of ceramics were up to 98 % [2]. We found that the complex oxides – analogues of pollucite - have high chemical and radiation stability. The obtained ceramic materials were irradiated with 132Xe26+ ions (E = 167 MeV) in the fluence interval from 6•1010 to 1•1013 cm-2. The amorphization took place at a fluence of 1.2•1012 cm-2. The conditions of the metamict form transition into the crystalline form on heating were found. The crystal-chemical modeling of isostructural compounds was carried out with a deficit of cesium in the cavities of the structure of the general formula Cs1-x[Mg1+x-yR0.5-2x +0.5yLi0.5yP1.5+xO6], where R = B, Al; 0 ≤ x ≤ 0.2; 0 ≤ y ≤ 0.8. References: 1. Loginova E.E., Orlova A.I., Mikhailov D.A. et al. // Radiochemistry, 2011. V. 53. № 6. P. 593-603. 2. Orlova A.I., Troshin A.N., Mikhailov D.A. et al. // Radiochemistry, 2014. V. 56. № 1. P. 98-104.
Speaker: Mr Aleksey Troshin (Lobachevsky State University of Nizhni Novgorod)
• 179
Colliders and their Possible Georadiochemical Effects on the Environment
A dangerous factor is considered, which may precede the formation of black microholes, strangelets, magnetic monopoles and other objects in colliders, – the probability of turning the Earth into the "iron planet" or the flow of iron asteroids and meteorites. Proceeding only from real experimental evidence and theory-based provisions: 1) the quark-gluon plasma is already an experimental fact, 2) the dependence of the binding energy per nucleon from the number of nucleons in the nucleus is both experimentally and theoretically accurate, so we can assert that at the present moment the technical conditions for an uncontrolled conversion of all the chemical elements in the elements of Fe-Ni-Co group are already established, with the probability of catastrophic consequences for the Earth still extremely low, but 3) the possibilities of colliders are growing at a high speed and the dangerous threshold can be overcome in a very short time. A special group, established by CERN to evaluate the safety of experiments, presented a report which states that the Large Hadron Collider is not dangerous. The other dangerous process, which may occur from the uncontrolled formation of quark-gluon plasma of large volume and density in the conditions of the CERN experiment, is not considered at all. During this process, any substance turns into a cloud of elementary particles, which will condense in the process of cooling into the most energetically favorable state – the elements of the iron subgroup, which have the greatest values of the binding energy of the nucleons in the nucleus. The released energy will support this process till the complete conversion of all the chemical elements of the substance into the elements of the iron subgroup. It is believed that the first experimental results on the quark-gluon plasma were obtained in 1990 at CERN Super proton synchrontrone (SPS) (the concept of a fireball has deeper historical roots [1] and appeared for the first time in the physics of cosmic rays). Then, in 2000, also at CERN, the discovery of this "new state" of matter was announced. In the colliders, the energy of particles and the density of their torrent are continuously increasing, which naturally leads to a more "hot" chromoplasma, and to the increase of its volume and density. According to the prevailing ideas of today, the unlimited expansion of the fireball is very unlikely, but there are other opinions. For example, Academician E. Feinberg believed that the lifetime of fireballs is greatly underestimated [1]; Heisenberg’s calculations were already giving the abnormally high cross-section of their formation [2]; and Fermi has long ago presented the scheme which allows a fireball to expand unlimitedly in the flow of the accelerator [3]. The works of B.L. Ioffe were also published [4], which presented the abnormal parameters of the fireball, significantly different from L.D. Landau’s calculations [4]. The probability of formation of an abnormally large fireball could be significant. The reaction of "ferruginization" may obtain a global or nearly global nature. The possible protective measures to prevent the probable future catastrophe are being considered, as well as the hazardous geotectonic conditions of the experiments at CERN. 1. ФейнбергЕ.Л.- Усп.Физ.Наук,Т.139,вып.1,1983,с.3-49; 2. Heisenberg W. - Zs. Phys., 1952, Bd. 133, S. 65; 3. F e r m i E.-Phys. Rev., 1951, v. 81, p. 683 ; 4. Иоффе Б.Л. - ЖЭТФ,1974,т.20,вып.6, с.360-362
Speaker: Mr George Ryazantsev (B.)
• 180
Comparative study of radioactivity in NORM samples using ICP-MS and Instrumental Neutron Activation Analysis
As an attempt to reduce the social costs and apprehension arising from radioactivity in the environment, an accurate and rapid assessment of radioactivity is highly desirable. Naturally occurring radioactive materials (NORM) are widely spread throughout the environment. Concern regarding the radioactivity from these materials has therefore been growing over the last decade. To determine the proper handling options, a rapid and accurate analytical method that can be used to evaluate the radioactivity of radionuclides (e.g., 238U, 235U, 232Th, 226Ra, and 40K) should be developed and validated. Typically, α-spectrometry has a major disadvantage of a long counting time, while it has a prominent measurement capability at a very low activity level of 238U, 235U, 232Th, and 226Ra. Contrary to the α-spectrometry method, a measurement technique using ICP-MS allows radioactivity in many samples to be measured in a short time period with a high degree of accuracy and precision. For both techniques, however, the pretreatment process consequently plays an important role in the measurement uncertainty. Thus, a method development and validation should be performed. A method was developed for a rapid analysis of natural radioactive nuclides using ICP-MS. A sample digestion process was established using LiBO2 fusion and Fe co-precipitation. A magnetic sector field ICP-MS (SPECTRO MS) was used for a rapid determination of the radionuclide concentration. For an evaluation of the accuracy and precision of the method, certified reference materials (CRMs) were analyzed using an established process. The analytical results of CRM samples were in agreement with the certified concentration values. In this study, the radioactivity concentration in raw materials (e.g., bauxite, bentonite, ceramic, clay, monazite, and zirconium sand) and by-products (e.g., coal fly and bottom ash) was determined using ICP-MS and LiBO2 fusion method. To validate the analytical results using the method evaluated in this study, duplicate samples were also analyzed using an instrumental neutron activation analysis.
Speaker: Dr Jong Myoung Lim (Korea Atomic Energy Research Institute)
• 181
Comparative study of the thermal, hydrolytic, radiation stability and mechanical properties of Cs, Ba, Sr, and Ln-containing ceramic materials for radiochemical problems and applications.
Knowledge of the behavior of materials in radiation fields need if ones are elaborated for radwaste immobilization. Also it is important to prepare a ceramic with high density for aims: medical, research and material science problems, consolidation and transformation of radwaste. Among these materials deserve special attention mineral-like. Natural "experience" shows the ability to save (stability) of mineral-like materials under the influence of heat, pressure, hydrolytic solubility, radiation fields in a long time. Used for a long time methods for the synthesis of ceramics (cold pressing with following hightemp firing; multistage hot pressing) have several disadvantages: prolonged exposure to high temperature, low relative density of the resulting product, multi-stage processes, high energy and time costs. This work focuses on the development and multitasks application of new methods for the synthesis of high-density ceramics (Spark Plasma Sintering), reducing temperature, duration of the process and the number of steps on the example of monophase polycrystalline compounds. The objects of research were following compounds: Ca0.25Sr0.25[Zr2(PO4)3] (NZP-type); CsBa(Sr)[Fe2(PO4)3], Cs2[Mg2(WO4)3] (langbeinite type); NdPO4 (monazite type); Y(1-x)GdxPO4 (x=0, 0.05, 0.25; xenotime type); Cs0.875Ba0.125Li0.125Zn0.875Al0.5P1.5O6 (pollucite type). This chemical compositions were choose as stable mineral-like matrixes, containing Cs, Ba, Sr, Ln jointly or separately. At the first stage we obtained the samples of composition as powders by using the sol-gel process. Step by step the gel formed and then powders were heated, dispersed and examined by X-Ray analysis. Then ceramics on the base of compounds named were sintered by Spark Plasma Sintering (SPS) method. Obtained powders and ceramic pellets were tested for thermal stability up to 1350 °C, hydrolytic stability in distillated water (20 and 90-100 °С (Soxhlet extractor, 7-28 days). Prepared cylindrical tablets (d=10, 20 mm) were irradiated with accelerated Xe-ions (E=167 MeV) stream at 6•1010 - 1•1013 fluences (1/sm2). The experiments were carried out at room temperature on the IC-100 FLNR JINR (Joined Institute of Nuclear Research) cyclotron. All compositions were stable after heating up to 1100 °C. High relative density was reached for all compounds by using SPS method for 0-5 min: 99,6-99,9 % (NZP); 96,2-99,9 % (langbeinite); 98,3 % (monazite); 98,8-99,9 % (xenotime); 99,9 % (pollucite). Ceramic materials with NZP and pollucite-like structure were stable after radiation till 1•1013 fluences (1/sm2) [1, 2]. 1. A.I. Orlova, V.Yu. Volgutov, D.A. Mikhailov et al. // J. Nuc. Mat., 2014, vol. 446. P. 232 – 239. 2. A.I. Orlova, A.N. Troshin, D.A. Mikhailov et al. // Radiochemistry, 2014, Vol. 56, No. 1, pp. 98–104.
Speaker: Mr Dmitriy Mikhailov (Nizhny Novgorod State University)
• 182
Composite Dust-Suppressing Coatings Containing Nanosized Sorbents Selective to Cesium, Cobalt, and Nickel Radionuclides
Here we report on development, characterization and performance evaluation of new materials based on selective to radionuclides nanosized sorbents stabilized in water dispersible nanoparticles (latexes). These new materials can be applicable as fixatives (dust suppressors), when latexes are film-forming, and as colloid stable sorbents for decontamination of solid bulk materials, when any type of latex, preferably containing carboxylic groups on the surface, is used. Two different series of polymeric nanoparticles were synthesized and tested as a polymer matrix for inorganic sorbents immobilization. The first type of particles was based on polystyrene and composed of polystyrene either pure (homopolymer) or copolymerized with different amounts of acrylic acid in order to obtain carboxyl-functionalized latex particles. The second type was poly(silane acrylate)-based copolymer nanoparticles, consisting from butyl acrylate, methyl methacrylate, polymerizable silane and functional comonomer (either methacrylic acid or aminoethyl methacrylate hydrochloride). All particles were synthesized in direct (oil-in-water) miniemulsion system by free-radical (co)polymerization. As selective inorganic materials colloidal SnO2 and MnO2 with mean particle size 10 nm and 200 nm, respectively, have been synthesized. Co(II) ferrocyanides were synthesized directly in the presence of carboxylic latex particles. Composites containing SnO2 nanoparticles selective to radionuclides of nickel and cobalt have been prepared using carboxylic and aminolatexes as a martrix, the maximum loading degree was about 60 mg of SnO2 per 1 g of latex. Sorption properties of composite latex/inorganic sorbent materials have been investigated toward 63Ni, 57Co (SnO2), 137Cs (Co (II) ferrocyanides), 90Sr (manganese oxides) in the presence of competing ions. Distribution coefficients up to 105 ml/g were reached for cesium radionuclides and for nickel and cobalt radionuclides on SnO2 in NaNO3 solutions The highest distribution coefficients of 90Sr (~3500 ml/g) in the presence of competing Ca2+ ions (0.1 g/L) were reached for manganese oxides. Dust suppressing formulations based on film-forming poly(silane acrylate) latexes containing Co(II)ferrocyanide and poly(silane aminoethyl) latexes containing SnO2 have been prepared and drop casted on model contaminated sand. The leaching of 137Cs and 57Co radionuclides from coated sand surface was efficiently suppressed (leaching degree below 1%), when the content of Co(II) ferrocyanide and SnO2 in composite coatings was as low as 1.3•10-6 mol/cm3 and 8.3•10-4 mol/cm3, respectively. Acknowledgements: Financial support for ERANET-Russia project (STProject-144) of the 7th EU Research Framework Programme is gratefully acknowledged.
Speaker: Dr Dmitry Marinin (Institute of Chemistry FEBRAS, Vladivostok, Russia)
• 183
Decreasing of Transfer of Caesium and Strontium Radionuclides from Soil to Vegetation
Decreasing of transfer of radionuclides from soil to vegetation is the main purpose of remediation of radioactively contaminated lands with the aim of their returning to farming industry. The method of addition of sorbents to soils is seemed to be the most afficient in these cases. Using sorbents should possess affinity to natural systems, high specificity and selectivity and also irreversibility of sorption of radionuclides for effective retention of radionuclides as wel as to prevent their migration into vegetation and further movement through food chains. A number of publications suggest to use natural and modified aluminosilicates for remediation of territories but there were no comparative studies of use of various materials, questions of selectivity and reversibility of sorption of radionuclides have not taken into an account. Comparative study of specificity, selectivity and reversibility of sorption of caesium and strontium radionuclides by natural aluminosilicates (glauconite from Karinskoe deposit (Russia) and clinoptilolite from Shivyrtooinsky deposit (Russia)) and modified ferrocyanide sorbents based on them is presented in this work. The natural glauconite sorbs caesium from tap water with distribution coefficient Кd = 10(3.5±0.1) mL/g, static exchange capasity of Cs is 11.0 mg/g; it shows lower specificity to strontium: Кd = 10(2.5±0.1) mL/g, static exchange capasity = 9 mg/g. For clinoptilolite these parameters are for caesium Кd = 10(4.4±0.5) mL/g, static exchange capasity 210 mg/g; for strontium Кd = 10(3.5±0.1) mL/g, capasity = 12 mg/g. Ferrocyanide sorbents concentrate caesium radionuclides more effectively: distribution coefficient of Cs from tap water by mixed nickel-potassium ferrocyanide based on glauconite is 10(5.9±1.6) mL/g, static exchange capasity of Cs is (63.0±2.0) mg/g; for mixed nickel-potassium ferrocyanide based on clinoptilolite these characteristics are respectively 10(7.4±1.3) mL/g, 500 mg/g. In case of modified sorbents specificity to strontium remains the same as for natural aluminosilicates. Reversibility of sorption of caesium by natural glauconite and ferrocyanide sorbent was determined as caesium leaching degree from saturated samples. High caesium leaching rates and degrees are typical for natural glauconite irrespective of leachant salinity: total degree of leaching after 35 days of leaching was: mineral water = 63.4%, tap water = 41.6% and rain water = 28.8%. For flauconite modified by ferrocyanides total degrees of leaching under the same conditions were: mineral water = 1.5%, tap water = 14.6% and rain water = 6.6%. Thus, it could be expected, that there will not be reliable retention of caesium by solid phase after addition of natural aluminosilicates into soil. Surface-modified glauconite and clinoptilolite provide rather lower caesium leaching degrees, so it can be successfully used for remediation of lands contaminated by radiocaesium. Also the assessment of efficiency of extraction of caesium from soil solutions (solutions after leaching from various types of soils). It is shown that using of modified sorbent is more economically feasible, because it is needed 500 mg of ferrocyanide sorbent vs. 25000 mg of natural glauconite per 1 L of oil solution to achieve the same decontamination degree. The quantity of sorbent to introduce as well as its efficiency will depend on type of soil at contaminated lands. Results of experiments have shown that decreasing of transfer of caesium radionuclides from tested soils to vegetation after addition of mixed nickel-potassium ferrocyanide based on glauconite was 20 times. Thus, it is shown that modification of natural aluminosilicates by ferrocyanides allows to increase their sorption and mechanical features and to make sorption of caesium more selective and almost irreversible. These features allow to recommend modified aluminosilicates for remediation of radioactively contaminated lands
Speakers: Dr Anna Voronina (Ural Federal University), Mrs Marina Blinova (Ural Federal University)
• 184
Developing of a method of determination of concentration and isotopic composition of thorium in natural waters in radiation monitoring
Determination of the isotopic composition of natural radionuclides in natural waters is an integral part of radioecological monitoring. A full analysis of thorium radionuclides should solve two problems: determination of analytical concentration and isotopic composition. The main problem in the analysis of fresh water with low thorium content is preconcentration step; for samples with a high salt content and the complex composition it is removal of the most non-radioactive contaminants and alpha-emitters, e.g. uranium, preventing the preparation of high-quality source for alpha spectrometry. The aim of this work is to develop a thorium preconcentration step for large volumes of natural water. Th-234 was used as tracer in all experiments. Coprecipitation with iron hydroxide (III) followed by precipitation on cellulose in frontal chromatography condition was choosed for preconcentration of thorium. Theoretical and experimental modeling of thorium coprecipitation with iron hydroxide was performed. Calculations of solubility of thorium hydroxide have shown that its own hydroxide phase is not formed in range of concentrations typical for natural waters. Therefore, coprecipitation with carrier (iron hydroxide) is the only possible way for thorium preconcentration. Processes of iron hydroxide precipitation and thorium coprecipitation with iron hydroxide from freshwater were studied by ultrafiltration method in dependence on pH, concentration of the thorium and iron (III). To isolate the precipitate of iron hydroxide, which contains thorium, we proposed filtration through a nozzle in frontal chromatography condition. Cellulose was used as a nozzle. The study allowed to determine conditions thorium preconcentration that provide thorium yield (98 ± 8) %: the concentration of the iron (III) is 100 mg / l; pH 6.5-7.5; sediment formation time - 1 hour , the flow rate through column with filtration nozzle ~ 130 ml/min*cm2 . Weight of nozzle depends on volume of the sample. The ratio of height to diameter of the column is not less than 1:10. Extraction of thorium from filter nozzle by ammonium oxalate solution was performed under dynamic conditions. The method of coprecipitation with cerium fluoride was used for preparation of samples for alpha-spectrometric determination of thorium isotopes. Coprecipitation method with further separation of the precipitate by ultrafiltration was selected due to the fact that uranium(VI) remains in solution under these conditions. By fluoride precipitation the quality of the sample depends on presence of calcium in the sample, forming a crystalline precipitate. Therefore, solubility of cerium, thorium and calcium fluorides with taking into account hydroxycomplexes was calculated to optimize the conditions for sample preparation for α-spectrometric determination of thorium isotopes. The results have shown that precipitation of calcium fluoride does not occur, while thorium and cerium fluoride will be precipitated when concentration of fluoride ions was 1,8∙10^-5 mol/l ≤ CF- ≤ 5,0∙10^-3 mol/l. Optimal concentrations of cerium nitrate and hydrofluoric acid, providing a quantitative release of thorium and good quality of sample for α-spectrometry were determined. Thorium yield in fluoride precipitation step was (98 ± 9)%. Total yield of thorium in the whole method, defined by thorium-234 was (98 ± 11)%. Decontamination factor of uranium for samples containing up to 500 g/l of uranium according to the methods was ~ 10^2 ÷ 10^3. Thus, the proposed method make it possible to perform a thorium preconcentration from large volumes of natural waters, providing its quantitative extraction and good separation from uranium. This methom can be recommended for determination of total analytical concentration of thorium and its isotopic composition by alpha-spectrometry.
Speaker: Anna Paliga (ФГАОУ ВПО «УрФУ имени первого Президента России Б.Н.Ельцина»)
• 185
Development of automated system for continuous remote control of radioactivity emitted by nuclear power plants
Automated system for radiation control of air space near the nuclear power plant based on using of non-stop remote gamma-spectroscopic control of nuclear power plant radioactive emission (mainly from ventilation pipe) is developed. The task of the system consists in estimation the potential risk of terrain contamination outside the nuclear power area. The system should provide authorities of different level with information concerning radionuclide composition and dose rate, both in the case of normal emission and the emergency one up to level 7 (according to the INES international scale of nuclear events). It is extremely important to detect early stage of any event. The system hardware consists of spectrometric stations (manufactured in Russia) connected with computer’s net. The station includes the collimated scintillation NaJ (Cs) detector of 63×63 mm size, connected with intellectual MCA. It has been found that for reliable detection of radioactive emission of the nuclear power plant eight stations evenly located at the 500-800 meters distance from the ventilation pipe are sufficiently. The input information and results of data processing are stores in SQL-data base. The data processing software is based on the original algorithms coded by C# language. It includes processing of scintillation gamma-ray spectra, including evaluation of multiplets. A method for computation of full energy peak efficiency for voluminous atmospheric sources (radioactive gas stream escaping from ventilation pipe) has been developed. The computation uses the dependence of full energy peak efficiency value for arbitrary point as function of distance and angle. The atmospheric stream geometry is set by normal distribution, with parameters dependable on meteorological state of atmosphere. The computations of full energy peak efficiency for voluminous radioactive atmospheric sources a modeling by the Monte-Carlo method has been used [1] The original method for radionuclides identification is developed. Both mathematical methods and elements of expert system are used. To increase the identification reliability it is suggested to use different radionuclides libraries optimal to various types of emergency events using fuzzy logic. It is assumed that the developing system will be integrated with system of radiation control of nuclear power station. It will allow assisting decision support center to accept adequate solutions in the case of problems. The successful tests of different parts of the system were carried out at the Kalinin and Kursk nuclear power plants, Russia. [1] D.S. Grozdov, V.P. Kolotov, Y.E. Lavruhin, N.N. Dogadkin. Computation of full energy peak efficiency for voluminous radioactive atmospheric sources using remote scintillation gamma-ray spectrometry. Abstract presented at RadChem14.
• 186
Distribution of 137Cs, 238,239+240Pu and 241Am in soils and lakes from the Central Spitsbergen
Soils play an important role in accumulation of airborne radionuclides. Plutonium isotopes released by nuclear weapons testing are still present in the environment, especially in soils. There are several sources of radioactive contamination in the European sector of the Arctic. The most substantial include global weapons fallout, fallout from nuclear weapons testing near Novaya Zemlya and from Chernobyl accident, and discharges from the nuclear reprocessing plants Sellafield (UK) and La Hague (France). The aim of this study was to investigate activity concentrations, activity ratios and inventories of 137Cs, 238Pu, 239+240Pu and 241Am in 8 soil profiles and 3 bottom sediment profiles from tundra lakes of Petuniabucta coast (Central Spitsbergen). The loose and poorly developed soils were collected from raised marine terraces covered with sandy-gravel sediments (PET1, PET2, PET3) and from coarse-grained screes (PET4, PET6, PET8). The Ebbadalen tundra lakes (PEL1, 2, 3) occupy shallow depressions underlain by mineral soil or thin peat in permafrost terrain. Results obtained in this study show differences in activities of artificial radionuclides among the investigated profiles. The highest activities of 137Cs, 238Pu, 239+240Pu and 241Am observed in profile PET4, reached 123±11 Bq/kg, 0.13±0.04 Bq/kg, 3.82±0.31 Bq/kg and 1.2±0.1 Bq/kg, respectively. Artificial radionuclides in most of the tundra soils were concentrated in the upper 4 cm but in one profile (PET5) maximum activity concentrations each radionuclide was observed at 10 cm depth. The deeper occurence of radionuclides in profile PET5 can be explained by occasional accumulation of aluvial deposits in that site. Location of activity maxima points to accumulation of 10 cm thick deposits during last 50 years. The activity ratios provide important information on the origin of radioactivity in soils, as they can be used to distinguish between global (stratospheric) and regional (tropospheric) sources of these radionuclides. Isotopic analysis of plutonium reveals provenance of this radionuclide, for example whether the plutonium burdens are associated with bomb fallout or are derived from other sources. The 238Pu/239+240Pu activity ratios varied from 0.02 ± 0.01 to 0.07 ± 0.02, suggesting global fallout as the dominant source of Pu (0.03-0.05). The 239+240Pu/137Cs activity ratios varied from 0.02 ± 0.01 to 0.09 ± 0.02 and exceeded published global fallout ratio for Svalbard of 0.05. The 241Am/239+240Pu activity ratios ranged between 0.32 ± 0.04 and 1.24 ± 0.13 and exceeded the global fallout ratio for Svalbard of 0.37 due to the relatively higher geochemical mobility of Pu vs. Am and/or ingrowth of Am from the decay of 241Pu. The 137Cs inventories in each profile were lower than the deposition fluxes (2.2 kBq/m2) reported for Svalbard. The 239+240Pu inventories varied between 20.1 ± 1.6 to 50.3 ± 5.0 Bq/m2 and exceeded values of 239+240Pu 14 - 26 Bq/m2 from atmospheric weapon testing. This study was supported by the Foundation for Polish Science PARENT-BRIDGE Programme co-financed by the EU European Regional Development Fund.
Speaker: Dr Edyta Łokas (H.Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences)
• 187
Effect of high ionic strengths on U(VI) retention in montmorillonite
Argillaceous rock and clay minerals have properties that make them very suitable for nuclear waste storage. They are practically impermeable and have high sorption capacities. North German clay deposits feature pore waters of particularly high ionic strengths, ranging from 1.8 mol/l to 3.3 mol/l. in the depths relevant for nuclear waste repositories.[1] To enable an informed decision about the long term safety of nuclear waste disposal, the effect of high ionic strengths on radionuclide retention needs to be taken into account. This work focuses on the uranium retention on montmorillonite (as model clay) in sodium and calcium chloride brines. These conditions are based on the Konrad mine that serves as reference site. There, montmorillonite is a major component. The ground water at a depth of about 480 m has sodium and calcium chloride as main components with an ionic strength of around 2.9 mol/l, and a pH between 5.75 and 6.85.[1] The effect of ionic strength on uranium sorption on montmorillonite is very small. A true ionic strength effect, which is a decrease of sorption with ionic strength, can solely be observed below pH 6 and only up to an ionic strength of 2 mol/l sodium chloride. In calcium chloride, there are effects that show a positive correlation between sorption and ionic strength in the alkaline pH range but these can be explained with secondary phase formation rather than true ionic strength effects. In the presence of carbon dioxide, U(VI) sorption decreases in the alkaline pH range regardless of electrolyte due to the formation of uranyl carbonate species. In the absence of carbon dioxide, U(VI) sorption at alkaline pH remains almost as high as the value at the sorption maximum. In general, the sorption maxima in both sodium and calcium chloride lie in the pH range of natural groundwaters in North German clay formations. Relative uranium uptake at the sorption maxima exceeds 99% for both electrolytes. Desorption experiments show that uranium sorption on montmorillonite in sodium chloride is largely reversible except for very high ionic strengths. In calcium chloride, on the other hand, reversibility depends less on ionic strength and more on pH.[2] Further results that will be presented concern uranium sorption in a mixed electrolyte that is modelled on the naturally occurring ground waters of the Konrad site. [1] Brewitz, W. (1982) Eignungsprüfung der Schachtanlage Konrad für die Endlagerung radioaktiver Abfälle. Gesellschaft für Strahlen- und Umweltforschung. [2] Zehlike, L. (2013) Durchführung von Sorptions- und Desorptionsversuchen von Uran(VI) an Montmorillonit, Bachelor thesis, TU Dresden.
Speaker: Ms Katharina Fritsch (Helmholtz-Zentrum Dresden-Rossendorf)
• 188
Examination of 238Pu, 239,240Pu and 137Cs radionuclide diffusion in soils and lake bottom sediments
Application of an appropriate model and transfer parameters for radionuclide migration in soils and fresh water ecosystems (e.g. lakes) to predict the long-term radionuclide behaviour is of great concern. Transfer of radionuclides in lake ecosystem is mostly governed by the processes of diffusion, perturbation of soil or lake bottom sediments and transport of long- lived radionuclides with the water flows. In order to evaluate values of diffusion coefficients 3 core samples were taken in the vicinity of Vilnius city (Lithuania): in upland and flooded soils (to the depth of 30 cm) as well as in lake bottom sediments (to the depth of 40 cm). 238Pu, 239,240Pu and 137Cs activity concentrations in profile layers were measured. Two radionuclide activity concentration peaks were characteristic in flooded and upland soil cores. In sediments, single radiocesium and plutonium activity concentration peaks were observed at the same depth, which depends on the sedimentation rate in the lake (~4.7 mm•y-1). The activity concentration 238Pu/239,240Pu and isotopic 240Pu/239Pu ratios have shown the global fallout from nuclear weapons testing to be the main Pu contamination source in the studied environmental systems. 137Cs/239,240Pu activity concentration ratio values were sufficient for the evaluation of the contribution of Chernobyl-derived radiocesium. Fitting the deepest slopes of the vertical profiles in the lake bottom sediments of the respective radionuclide activity concentration peaks with Gauss functions, it was found that effective diffusion coefficients (for the period from 1963) of plutonium and radiocesium were ~0.21 and ~0.16 cm2∙y-1, respectively. According to deeper slopes of radiocesium activity peaks the determined diffusion coefficients in cores of the flooded and upland soil samples were also about the same (~ 0.06 and ~0.07 cm2•y-1, respectively). Deepening rates of the activity concentration peaks related to the supposed mobile fraction of both radionuclides were larger in the flooded soil core from the old channel (~0.27 cm•y-1). In the upland soil core they were equal to ~0.16 and to ~ 0.12 cm•y-1 for plutonium and radiocesium, respectively. Acknowledgements. This research was funded by a grant (No. MIP-041/2012) from the Research Council of Lithuania.
Speaker: Mr Sarunas Buivydas (State Research Institute Center for Physical Sciences and Technology)
• 189
Exploration of radon-rich waters in crystalline terrains by gamma method in spite of radioactive disequilibrium
Goliáš V.1, Hrušková L.1, Lipanský T.1, Przylibski T.A.2, Procházka R.3 1Charles University in Prague, Faculty of Science, wiki@natur.cuni.cz, lehruskova@centrum.cz, tomas@watersystem.cz 2Wrocław University of Technology, Faculty of Geoengineering, Mining and Geology, tadeusz.przylibski@pwr.wroc.pl 3Lesní 1079, Dobřichovice, Czech Republic, choda@seznam.cz Keywords: groundwater, mineral water, springs, gamma dose rate, radon progeny Radioactive mineral waters (rich in dissolved 222Rn) are highly valued for their medical use. Therefore they have been intensively explored in last years (2005–2014) in Orlica-Sněžník dome and Krkonoše-Jizera crystalline areas. Springs of radioactive medicinal water are bound up with the Cambrian/Ordovician orthogneisses (the Krkonoše, Kowary and Jizera orthogneiss). For these purposes an exploration method has been developed as a combination of GIS (ArcMap 9.1–10.1) for the area preparation followed by field radiohydrogeochemical mapping. As basic GIS layers a geological map 1:50000, topography, airborne gamma spectrometry, linear structures from Remote Sensing were used. The field radiohydrogeochemical mapping was realized in scale 1:10000 in perspective areas selected by GIS preparation. All water manifestations (wetlands, springs, man-made objects) were measured by gamma as an indicative method. In case of positive results (increased gamma in water) the water was sampled and a passportized field record was written. The exploratory groups were equipped with sensitive field scintillometers RP-11 with RFS-05 gamma probes. The 222Rn activity in water samples was determined by the emanometric method (RP-25) at the field base. Control analysis in the laboratory by LSC (QUANTULUS) was made. Standardization of all methods is commonplace. More than 50 water sources with activity above 1500 Bq/L (i.e. "radioactive mineral waters") were found in the whole territory. The highest radon activity reaches 6215 Bq/L in case of the Michael spring near Nové Město p. Smrkem. Waters are cold (5–9.5 °C) and low-mineralized (TDS < 100 mg/L), 222Rn is the only important component. Gamma activity of fresh flow water is close to zero; it is free of the short-lived 222Rn gamma active progeny (214Pb and 214Bi). Field measuring of fresh water gamma activity growth indicates its effective age about 7 minutes only. But the gamma activity is really detectable in frequent cases where there is a slowdown in the flow and mud or sediment of organic material is created. In fact, we have a lot of evidence from the field Gamma dose rate in water reaches 4624 nGy/h. Relationship of gamma (gamma dose rate in water) and radon-in-water activity is complicated; both quantities correlate freely. It depends on the specific situation of every single spring. Generally we can say that the gamma dose rate is a function of radon-in-water activity, water velocity and flowing water volume: Dw = f(Av, v, V). Gamma method, in spite of radioactive disequilibrium, is useful for exploration of radon-rich waters in crystalline terrains on the basis of our empirical findings in the field, much better than the "blind" method.
Speakers: Ms Lenka Hrušková (Charles University in Prague), Dr Viktor Goliáš (Charles University in Prague)
• 190
Extraction of rare earth elements from the natural and man-made raw by using supercritical carbon dioxide
In connection with the development of modern high-tech industries and changing market conditions in the last few years have seen a growing interest in rare-earth elements (REE). This necessitates the creation of new technologies for processing of mineral raw materials, as well as various industrial wastes and secondary resources. Virtually all fields of REE are part of complex ores, incorporating a wide range of components. In this context a crucial role in the development of deposits, processing of ores and other sources play an extraction and sorption methods are widely used for the extraction, separation and purification of individual REE. In this paper proposed the use of supercritical fluid extraction method for the isolation and separation of REE, uranium and thorium in the processing of mineral raw materials and industrial waste such as monazite concentrate and phosphogypsum. On the example of organophosphorus reagents such as TBP, CMPO, TOPO, and nitrogen-containing ligands DMDOGEMA and TODGA, as well as TBP-HNO3 adduct we studied the possibility of sorption of REE by the previously synthesized solid phase extractants, based on carbon nanotubes and polystyrene Taunit media. There was a fundamental possibility of separation of REE, uranium and thorium, the above extractants and their allocation to individual phases using supercritical carbon dioxide. A scheme for the processing of monazite concentrate and phosphogypsum.
Speaker: Dr Maxim Samsonov (Vernadsky Institute of Geochemistry and Analytical Chemistry of Russian Academy of Sciences)
• 191
First Shrinkage Parameters of Slovak Bentonites Considered for Engineered Barriers in the Geological Repository for Radioactive Waste and Spent Nuclear Fuel
In a previous research for the deep geological repository of radioactive waste and spent nuclear fuel, the swelling potential of bentonites from Slovak deposits was evaluated by indicative parameters (Atterberg liquid limit) and by swelling pressure tests (Adamcova et al., 2009). The noticed absence of data on shrinkage behaviour initiated a pilot research of bentonite shrinkage parameters in Slovakia (within the project VEGA 1/0828/13 granted by the Slovak Ministry of Education). Comparison of Slovak, Austrian, German and British Standards for shrinkage test methods showed that Slovak Technical Standards (STN) pertain to undisturbed soil samples, where shrinkage depends not only on the current moisture, but also on the grain size distribution and porosity. Shrinkage limit ws (%) and relative linear shrinkage Ls (%) determined according to the foreign technical standards are independent from those properties, because sample preparation brings all soils to equal starting conditions: sieved to grain size below 0.5 mm, water added to reach moisture w near the liquid limit wL, suspension smeared without bubbles into standard moulds. Applied Austrian ONORM B 4411: 2009 offers three test procedures for ws. First, ws was determined by manifold measuring of the sample weight and volume during drying. Calculation followed from the moisture vs. relative volume plot with a linear trend line. Results were compared to data from the other two methods. Highest Ls (up to 32.5% of the initial length) was observed in bentonite J250 from the Jelsovy Potok deposit, the best Slovak bentonite because of its swelling potential and excellent sorption properties for radionuclides (Galambos et al., 2009; Galambos et al, 2010a; Galambos et al, 2010b; Galambos et al., 2011). Reaching of the shrinkage limit (ws = 11%) was indicated also by a color change from light brownish grey (2,5Y 6/2) to light grey (2,5Y 7/1 - Munsell Soil-Color Charts, 2009). Because ws is lower than the equilibrium moisture of the bentonite J250 under room conditions, which is 14%, bentonite blocks might shrink and gaps between them open due to high temperature around the containers with radioactive waste and spent nuclear fuel in the geological repository, until water from the host rock mass intrudes and bentonite swells. Results indicated the necessity of further shrinkage tests, this time on bentonite powder compacted to high-density segments. Methods described in STN 72 1019 were recommended as relevant for the assessment of their total shrinkage. REFERENCES: Adamcova R., Frankovska J., Durmekova T. 2009. Engineering geological clay research for a radioactive waste repository in Slovakia. AGEOS, 1, 2, 2009, 71-82. Galambos M., Kufcakova J., Rajec P. 2009. Sorption of strontium on Slovak bentonites. Journal of Radioanalytical and Nuclear Chemistry, 281, 3, 347-357. Galambos M., Kufcakova J., Rosskopfova O., Rajec P. 2010a. Adsorption of cesium and strontium on natrified bentonites. Journal of Radioanalytical and Nuclear Chemistry, 283, 3, 803-813. Galambos M., Paucova V., Kufcakova J., Rosskopfova O., Rajec P., Adamcova R. 2010b. Cesium sorption on bentonites and montmorillonite K10. Journal of Radioanalytical and Nuclear Chemistry, 284, 1, 55-64. Galambos M., Rosskopfova O., Kufcakova J., Rajec P. 2011. Utilization of Slovak bentonites in deposition of high-level radioactive waste and spent nuclear fuel. Journal of Radioanalytical and Nuclear Chemistry, 288, 3, 765-777.
Speaker: Mr Adrian Krajnak (Comenius University in Bratislava, Faculty of Natural Sciences)
• 192
Humic acid as a sorbent modifier: humic acid induced synergetic sorption behavior of Prussian blue
Recent investigations show that sorption properties of solids in natural or synthetic humic acid (HA) solutions strongly depend on the ability of HA to form complexes with ions of sorbate and to interact with the surface of solids. In general, both factors are negative for the sorption technologies due to the known dramatic diminution of sorption processes in HA solutions. We found that industrially produced samples of Fe(II) cyanoferrate(II) (Prussian blue, PB) drastically change their sorption behavior in HA aqueous solutions in comparison with inorganic electrolyte solutions. Numerous experimental data showed that the revealed synergetic sorption of the couple “PB – HA” may be connected with two groups of factors: firstly, an effect of partial HA complex formation by cations in HA-solution which suppresses the known stereoselective sorption properties of d-metals cyanoferrates(II), and secondly, the growth of sorption affinity of some HA complexes of p-, d- and f-metal cations toward PB in the conditions when HA macromolecules don not interact with PB surface due to the same sign of electrostatic charge of interacting particles. In this presentation we show the results of investigation of the system “PB – HA” and discuss the reasons of the revealed enhancement of the sorption affinity of PB toward HA-complexes of ions of I-VI groups of D.I. Mendeleev Periodic System in the framework of the problem of chemical and radiochemical protection of the environment.
Speaker: Prof. Victor Remez (Ecsorb, the Compamy)
• 193
Immobilization of radionuclides into thermal insulation waste
Large amounts of low-density thermal insulation mineral wool waste contaminated by radionuclides arise from NPP operation. Melting of this waste reduces its volume by more than 10 times. Mineral fibers begin to lose their elastic properties at 440 оС and to soften at 700 оС. The minimum process temperature for molten fiber formation is ~ 1500 оС. Experiments were performed on mineral wool mats with specific activity of Cs-137(4.0-8.8)×108 Bq/kg. The experiments employed an industrial induction furnace as a waste melter. The melter was a graphite crucible with an opening provided at the bottom, through which the formed melt flowed down by drops into a receiving container. During the experiment, the melt discharge rate was from 1.8 to 2.2 kg/h, the melt temperature was 1350-1370 оС, and the rate of power consumption was 8.3 kW×h/kg. The solid-aerosol carry-over was not larger than 0.5 % and volatile loss of Cs-137 was only 2.8 % from the melting process. To reduce the mineral wool melting temperature from 1350-1370 оС to 1170-1190 0С, a low-melting fluxing agent, namely FeO (at least 10 wt. %), was used. The true density of the “frozen” mineral wool melt without addition of fluxing material was 2.7 g/cm3 and with addition of 10 % CaF2 the density increased to 2.8-2.9 g/cm3. Additional experiments were performed with crushed mineral wool incorporated into Portland cement modified by Cambrian clay as a sorption agent. The crushed wool was admixed to cement slurry with water-to-cement ratio of 0.7 and claycement ratio of 0.1. The density of produced cement compounds was about 1.8 g/cm3. Measurement of Cs-137 leaching from the thermal insulation waste forms has shown that addition of a fluxing agent to melt increases (almost by an order of magnitude) the radiocesium leach rate from the conditioned waste. But in any case this leach rate is of 10-7 g/cm2×day order after 150 days of the experiment. For comparison, Russia’s regulatory maximum value for Cs-137 leach rate from vitrified high-level waste is 1×10-7 g/cm2×day. For low- and intermediate-level wastes stored in standard concrete facilities, the acceptable rate of radiocesium leaching after 150 storage days is not higher than 1×10-3 g/cm2×day. Cemented thermal insulation waste forms with addition of clay comply with this requirement (the leach rate is ~1.0×10-4 g/cm2×day after 150 days).
Speaker: Prof. Vitaly Epimakhov (Nikolaevich)
• 194
Interlaboratory comparison on the determination of radionuclides in water, food and soil conducted by the National Atomic Energy Agency (NAEA), Poland
Proficiency tests (PT) on the determination of radionuclides in food and environmental samples have been organized by the National Atomic Energy Agency (NAEA), Poland, since 2004. The activity of the following radionuclides: 241Am, 137Cs, 3H, 239Pu, 226Ra and 90Sr were determined in water, food and soil. The PTs have been conducted by the Institute of Nuclear Chemistry and Technology (INCT), Warsaw, Poland and procedure adopted by the INCT is presented in the paper. The test materials: water, milk powder, wheat flour and soil, were prepared by spiking blank materials with standard solution of the radionuclide of interest. The activity concentrations were calculated and associated uncertainties were evaluated before sending the test materials to the laboratories. The results provided by the participants were statistically evaluated by means of z and zeta scores as well as using the International Atomic Energy Agency (IAEA) criteria for trueness and precision. Observed trends and some benefits for the participants have been presented.
Speakers: Ms Agata Oszczak (Institute of Nuclear Chemistry and Technology), Dr Leon Fuks (Institute of Nuclear Chemistry and Technology)
• 195
Isotopic Analysis As an Indicator of the Groundwater Stability
Natural radionuclides can be very good indicators of all hydrological and biogeochemical phenomena occurring in the water environment. Typical uses of environmental isotopes include the identification of source of water and solutes, determination of water flow paths, assessment of nutrients within the ecosystem, water budget. A few elements exhibit variations in their isotopic composition, resulting from radioactive decay its precursors present in the geological formations. These isotopic ratio variations can be used as natural fingerprint of rock – water interaction and applied in weathering and hydrology studies. In this work activity ratio of uranium and radium isotopes (234U/238U, 228Ra/226Ra), as well as of the stable strontium isotopic ratio (87Sr/86Sr) were determined in selected thermal groundwater, ground and surface water samples from central Poland. Uranium isotopes after co-precipitation with hydrated manganese dioxide were separated from other natural radionuclides by extraction chromatography resin (Dowex 1x8). The activity concentrations were determined by using α spectrometry with PIPS detector (Canberra). 228Ra was determined by gamma spectrometry after co-precipitation with MnO2, whereas 226Ra was determined by liquid scintillation counting. Strontium isotopic ratio after separation from other element by extraction chromatography resin (Dowex 50Wx8) was determined by thermal ionization mass spectrometry (TIMS). The average isotopic ratio for different type of water sample from Poddebice and Uniejow was shown in the Table 1. Table 1 Activity and isotopic ratio in different type water. location water type 234U/238U 228Ra/226Ra 87Sr/86Sr Poddebice thermal groundwater 0,923±0,020 1,64±0,35 0,708492±0,000014 deep well water 1,115±0,063 1,23±0,71 0,709454±0,000130 river water 1,027±0,116 2,67±1,14 0,709718±0,000466 Uniejow thermal groundwater 0,744±0,094 0,641±0,043 0,708441±0,000002 river water 1,232±0,161 1,95±0,49 0,709256±0,000059 The observed differences in these ratios confirms that the uranium, radium and strontium isotopic ratio can be useful indicator for determination of stability of the underground water reservoirs.
Speaker: Dr Magdalena Długosz-Lisiecka (Technical University of Lodz, Faculty of Chemistry)
• 196
Mitigating the environmental impact of high salt liquid radwaste concentrates incorporated into cement packages
The use of sulfuric acid instead of nitric acid for regeneration of cation-exchange resins arising from NPP operations produces sulfates which can form crystalline hydrates. Based on this capability, cement instead of bitumen can be used as a matrix for binding liquid radwaste (LRW), and high salt concentrates can be incorporated into Portland cement. Experiments simulating inundation of waste storage containers were performed. The experiments used a model salt solution representing an average composition of LRW from the VVER plants and containing 45% Na2SO4 of the total mineral content. Test solutions with a salt concentration from 200 g/l to 800 g/l and temperature of 80 оC were immobilized into cement matrix with water-to-cement ratio of 0.60 and addition of Cambrian clay as a sorbing agent. The percentage of added clay was about 10% of the total cement weight. The produced cement packages included from 6.7 to 25.1 wt. % of salts. Radionuclides were released from the cement surfaces into water with a rate of 10-1 g/cm2×day for the first 24 hours of the experiment and after 90 days the rate of radiocesium leaching by diffusion was below 0.5×10-3 g/cm2×day meeting Russia’s regulatory requirements (1×10-3 g/cm2×day) for standard concrete storage facilities. An increase in the test solution salt concentration from 200 g/l to 800 g/l resulted in an increase of the diffusion coefficient (De) from 0.5×10-5 to 2.8×10-5 cm2/day. However, this value is much below the regulatory requirements (≤ 8.6×10-4 cm2/day) on concrete disposal containers for radioactive waste. Since calcium sulfates are higher soluble than calcium aluminosilicate cement matrix, the maximum release of Cs-137 (2.2-3.0 % of the original activity), the most mobile radionuclide, from 200 L cement packages is mainly determined by surface leaching and occurs during the first three months of storage. This period is considered as the time of inundation scenario. The maximum diffusion leaching of Cs-137 taking its half-life into account will be observed during the first storage 20 years and the estimated release will be 10 times lower (below 0.2% of the original value) than that by surface leaching even for cemented concentrates with a salt concentration of 800 g/l. After 300 storage years the predicted radioactivity release will be maximum 0.004% of the original activity. Therefore, waste concentrates produced from LRW with a significant percentage of sulfate salts can be immobilized into Portland cement forms modified with sorbent clay which securely fix radionuclides even in case of high salt concentrates (up to 800 g/l).
Speaker: Dr Vitaly Epimakhov (Nikolaevich)
• 197
Mobility of radioactive cesium in soils originated from the Fukushima Daiichi nuclear disaster; Application of extraction experiments
The mobility of radioactive cesium (Cs) in contaminated soils affected by the Fukushima Dai-ichi nuclear disaster in 2011 was studied by single-step and sequential extraction experiments. The Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident in March 2011 resulted in serious radioactivity contamination in areas adjacent to the FDNPP. Meanwhile, radioactive cesium originated from the accident was detected over a wide range of the northeastern half of Honshu, the main island of Japan. The chemical forms of the released radioactive materials are still not clear. However, it is highly probable that the behavior and mobility of Cs newly deposited on soils due to the accident are different from those of stable Cs that has existed in soils before the accident, because of the difference in chemical forms between them. In this study, we have conducted extraction experiments using several extractants on radioactivity contaminated soils collected in Japan after the accident, then discussed extraction behaviors of radioactive and stable Cs connected to their chemical forms. The preliminary extraction experiments on non-contaminated soils revealed that stable Cs in soil was little extracted (less than 1 %) with Milli-Q water and 0.11M acetic acid (HOAc, pH 2.8), and that the extractants containing ammonium salts could partially extract Cs from the soils. The extracted portions of Cs with extractants containing ammonium salts are obviously higher than those with extractants containing cations other than ammonium like sodium, magnesium and calcium. This means that aqueous solutions containing ammonium salts are effective to extract Cs from soils. Based on the findings from the preliminary experiments, we performed the three-step sequential extraction using Milli-Q water, 1 M NH4OAc solution (pH 7) and 0.11 M HOAc in this order as extractants on some contaminated soils. The results of the sequential extraction experiments indicate that only a few percent of radioactive Cs was extracted with the 1 M NH4OAc solution, and additionally radioactive Cs was partially extracted at the HOAc step after the NH4OAc step, whereas extracted portions of stable Cs in each step were less than those of radioactive Cs. The result reveals that radioactive Cs newly deposited on soils due to the FDNPP accident has apparently a higher mobility than stable Cs commonly existing in the soils, although most of the radioactive Cs is kept fixed in soils, surviving extraction processes. We also performed single-step extraction experiments using several extractants on contaminated soils. The results of extractions with strongly basic solution suggest that humic acid plays an important role in the extraction of Cs from soils at least in the high pH range where it can dissolve, since the amount ratio of humic acid to fulvic acid and the content of total organic carbon (TOC) in the leachates seem to be correlated with the extracted portion of Cs from the soils. Thus the characteristics of the soils such as amounts of organic matters and their properties probably control the mobility of Cs in soils.
Speaker: Dr Yoshikazu Kikawada (Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University)
• 198
Mobilization of radionuclides and heavy metals from mill tailings in a northern boreal environment
There is increasing awareness of the radiological impact of non-nuclear industries that extract and/or process ores containing naturally occurring radioactive material (NORM). These industrial activities may result in significant environmental problems if the waste generated during processing is not adequately managed. In 2010, a new project was launched in Finland, the object of which is to study the mobility of radionuclides and heavy metals from diverse mill tailings in a northern boreal environment. The project is funded by the Academy of Finland and involves the Universities of Helsinki and Loughborough, the Geological Survey of Finland and the Finnish Radiation and Nuclear Safety Authority. Three sites are being investigated: Talvivaara nickel mine, a former phosphate mine in Sokli, Lapland and a former pilot scale uranium mine in Paukkajanvaara. The Talvivaara deposits in Sotkamo comprise one of the largest known sulphide nickel resources in Europe. It is an operational, open cast mine where Talvivaara Mining Company applies bioheap leaching to extract the metals from the ore. The leaching process has been shown to be heat generating and therefore suitable for the sub-arctic climatic conditions of Eastern Finland. In heap leaching, uranium dissolves in the pregnant leach solution (PLS) along with main base metals. Currently, the uranium is diverted into a gypsum pond. The radioactive progeny from the 238U series are also mobilized and fractionate depending on chemical properties and the ambient conditions. The Sokli complex is the westernmost deposit in the Devonian Kola alkaline rock province (ca. 365 Ma) and was discovered by Rautaruukki Oy in 1967. At the end of the 1970s, pilot scale mining and mineral processing took place at the site. The latter did not include chemical treatment of the apatite ore; processing was limited to removal of gangue minerals by physical methods. The mill tailings were deposited adjacent to the enrichment facility. The deposit is presently being developed by Yara International for beneficiation of the regolithic phosphate ore which overlies the magmatic carbonatite. In addition to the phophorus ores themselves, the carbonatite massif contains other minerals, such as niobium, iron and vermiculite. Apatite, which is known to exhibit elevated concentrations of uranium and thorium, is especially rich in the niobium ore. The Paukkajanvaara mining site started operation in 1959. The mine was basically a test site for assessing the feasibility of larger scale uranium mining. The ore was milled and enriched at the mining site. Mining proved to be uneconomic, and the operations ceased in 1961. In the late 1970’s the entrance of the mining shaft was covered with a concrete slab and the rest of the area including tailings, waste-water ponds etc., were abandoned. They were left untouched for nearly 30 years until Finnish Radiation and Nuclear Safety Authority initiated a review. Their results indicated that ambient radiation levels at the site had increased by 0.5 µSv/h as a direct result of the earlier mining operations. Rehabilitation was completed by 1994 after which the area was released for outdoor use without restrictions. The aim of the project is to generate new data from these three mines leading to a better understanding of the mobilization of radionuclides especially 226Ra, 210Pb and 210Po and heavy metals in a northern boreal environment. The results will also play an important role in estimating radiation doses to the local population resulting from past and anticipated disposal of mill tailings. A short summary of the results gained to date from each site is given in the poster presentation.
Speaker: Ms Hanna Tuovinen (University of Helsinki, Laboratory of Radiochemistry)
• 199
Monitoring of Radioactive Contamination of Polish Surface Waters in 2012-2013*
Radioactive isotopes of anthropogenic origin have appeared in the environment as a result of human activities. The main sources of these radionuclides were 1) atmospheric testing of nuclear weapons done in the years 1945-1980 with particular intensity in 1951-1958 and later in 1961-1962 and 2) the Chernobyl nuclear reactor accident in April 1986. The greatest contribution to the radioactivity level in the environment caused by artificial radionuclides was done by radioisotopes of cesium (137Cs) and strontium (90Sr). Monitoring of radioactive contamination in the terrestrial and marine environment in Poland was performed by Central Laboratory for Radiological Protection (CLOR) from early seventies. An extended monitoring program of radioactive contamination of Polish surface waters was carried out by CLOR since 1992, as a work done on request of the National Fund for Environmental Protection. In the frame of this monitoring the samples of water were collected twice of year (spring and autumn) from the sampling points located along two main Polish rivers: Vistula River and Odra River and in selected polish lakes situated in different part of the country. In 2012-2013 the water samples were taken from 7 sampling points on river Vistula and her tributaries, 5 sampling points on river Odra and her tributaries and 6 lakes situated in lake districts Drawskie and Lubuskie, region of Warmia and Mazury, Suwalki region and Lublin Province. Determinations of 137Cs and 90Sr in twenty liters water samples were performed by radiochemical method and activity concentration of these radionuclides were measured using low level beta counter. In 2012-2013 the average activity concentrations of 137Cs in the drainage basin of the Vistula ranged from 2.99 mBq/l to 6.58 mBq/l, of Odra River from 2.44 mBq/l to 6.11 mBq/l and in lake waters varied from 1.92 mBq/l to 7,96 mBq/l. The average activity concentrations of 90Sr in river waters ranged from 1.89 mBq/l to 8.00 mBq/l, and from 1.98 mBq/l to 22.84 mBq/l respectively and in water of lake from 1.69 mBq/l to 6.19 mBq/l Both, the annual average concentrations of analysed radionuclides and the data obtained for single determinations for water do not differ from data obtained in previous years. Monitoring of radioactive substances in Polish surface waters leads to the conclusion that 137Cs and 90Sr contamination of rivers and lakes on the Polish area is still low. Our determinations confirm that new releases of radioactive isotopes into the environment, with a significant impact on water contaminations, were not observed in Poland. *) This work was sponsored by National Fund for Environmental Protection, Poland
Speaker: Ms AGNIESZKA FULARA (CENTRAL LABORATORY FOR RADIOLOGICAL PROTECTION)
• 200
Natural radionuclide as a tracer in groundwater-surface water interactions at the artificial recharge system
Determining the relationship between surface water and groundwater systems is critical to understanding hydrogeological systems, protecting riverine ecosystems, and managing water resources. Due to its high activities in groundwater, the radionuclide 222Rn is a sensitive natural tracer to detect and quantify groundwater. In this study 222Rn and stable isotope were used as a tracer in groundwater and river water interaction. The short half-life(3.8 days) and chemically inert properties of radon make it a powerful and potentially useful tracer of hydrological processes at the fast interface interaction between surface and sub-surface water bodies. Study area is pilot artificial groundwater recharge system near Nakdong river in Korea. Rn-222 and stable isotope were used natural tracer to understand surface water recharge effect. Artificial recharge system was consist of four input and one pumping well. Rn-222 and stable isotope samples were collected during recharge operation time. For one day recharge operation period, Rn-222 concentration was decreased at the observation well groundwater. OBS-1 and 5 were decrease about 35 % due to surface water dilution effect but OBS-6 was 4 time increased due to surround groundwater input effect. The stable isotopes were similar trend with radon concentration but OBS-4 sample was different with other samples. This means different groundwater was introduced during recharge operation time. To understand surface water-groundwater interaction, 14 days artificial recharge experiment was performed and groundwater samples were collected during the operation time. This long-term experiment result showed radon concentration was not varied at the OBS-1 and 2. However, OBS-3 was increased and OBS-4 was decreased with time and about 200 hours passed radon concentration was not varied severely.
Speaker: Dr Yoon Yeol Yoon (Korea Institute of Geoscience and Mineral Resources)
• 201
Table wines are part of the Mediterranean diet and a common component of the adults’ diet in many countries. Wines are produced from vineyards grown in soils of different types from loam soils to granitic soils and in regions with different natural radioactivity levels. Twenty table wines, red and white, from large producers in several regions of Portugal, encompassing uranium provinces, were analyzed for naturally occurring radionuclides including uranium isotopes, 226Ra, 210Po and 232Th. Four other bottled table wines imported from Spain, France, USA, and Chile were analyzed for comparison. Uranium activity concentrations (238U) in Portuguese wines ranged from 1.1 to 12.9 mBq/L, 226Ra ranged from 2.0 to 22.0 mBq/L and 210Po from 14.8 to 74.4 mq/L. These ranges are nearly comparable to the activity concentration ranges determined in imported wines. Concentration of radionuclides in Portuguese wines were assessed by regions and it was observed that 238U concentrations were in average slighter higher only in wines from granitic regions of the Centre-North than from sedimentary regions of the south of the country. Radium (226Ra) concentrations in the wines were generally higher (by a factor of 2) than those of uranium, reflecting enhanced root uptake of radium from soils into grapes, such as commonly observed in many agriculture products. Polonium (210Po) concentrations in wines were in the average higher (by a factor of 4) than 226Ra concentrations, indicating that most 210Po in wine was probably from atmospheric depositions on vines and grapes rather than from root uptake. Radionuclide concentrations in table wines are comparable to concentrations of the same radionuclides in drinking water, and the radioactivity exposure through this ingestion pathway is minor. Results suggest that natural radionuclide levels in wine from several continents and latitudes may be very similar.
Speaker: Dr João M. Oliveira (Instituto Superior Técnico/LPSR)
• 202
Neutrino Emission and the Safety of Nuclear Objects
In 1979, there was a serious accident in the U.S. at the Three Mile Island nuclear power plant which involved two power-generating units. In 1986, the world witnessed a large-scale disaster in the USSR at the Chernobyl nuclear power plant that operated four power reactors. The last major accident occurred in March of 2011 in Japan. That accident involved six reactors. It is known that during the nuclear reactions in the reactors the torrents of anti-neutrino are released. At first, the neutrino emission was postulated as extremely high-penetrating, practically non-reactive to the matter. However, the capture cross sections of neutrinos, although really having very low values, are being measured at the extremely rough criteria. The situation here is somewhat similar to what happened to the neutron. Neutron, too, has high penetrating capacity, and often low capture cross sections, but, nevertheless, its cases of resonant interaction processes, that have sections many orders larger than normal, are well studied. From the very beginning of the discoveries of the neutrino, the "pervasive bias" has been adopted in the description of its properties, and little is known about its possible resonant interactions with matter and the research on these interactions. Resonant interactions are widespread in the microcosm and the physics of elementary particles, and it is not prudent to deny their presence for neutrinos, even with a very small probability. It must be said that for the relic neutrinos, the high level of interaction with matter is already widely discussed, but with the caveat that it is not typical for nuclear neutrinos. It is obvious for the greater part of the neutrino energy spectrum, but not for resonance. This is the first point. But there is another point: the interaction of neutrinos with matter is among the weak interactions, but, as pointed out by Academician B.M.Pontecorvo in 1970 [1,2], and discussed even earlier –¬¬ in 1964 – in the works of E.Bialynicka – Birula [3], the interaction between the particles them selves can proceed according to the mechanism of the strong interaction. This radically changes the situation; the presence of two or more neutrino fields close to each other can lead to a strong interaction between them, precisely: 1) to a sharp acceleration of the inverse beta process, which will lead to a large release of additional energy, and 2) to an increase in the fraction of excited nuclei in fissile material, which will lead to a decrease in its critical mass, and to an uncontrolled change of regimein the reactor to a supercritical state. Therefore, the work of two or more reactors located near each other is extremely worrying. The tendency to a greater increase in the number of cooperating power units (up to 7-8) is clearly showing. The conception of independence of the adjacent units, which is the prevailing conception at present, may appear misleading. At present, the most dangerous situations exist in Japan, Canada and India (NPPs with 7-8 power units); Ukraine has a nuclear power plant with 6 units (Zaporozhye); in Russia there are stations with 4-5 units. In addition to the mutual influence of nuclear power units, the question of the effect of natural neutrino torrents on their work also requires a systematic study. The methods of detecting the interactions of nuclear power units according to the neutrino mechanism are being discussed. 1. Б.М. Понтекорво, Успехи физ. Наук,104,№1,10(1971); 2. D. B a r d i n, S. B i l e n k y, B P o n t e c o r v o, Phys. Lett. 32B, 121 (1970); 3. Ζ.Bialynicka - Birula, NuovoCim. 33, 1484 (1964)
Speaker: Mr George Ryazantsev (B.)
• 203
New insights into uranyl interaction with proteins
Given uranium toxicity, comprehension of uranyl interaction with biological material of human relevance is of utmost importance, from the whole body scale to the molecular level. At the molecular level, uranium interaction with proteins has attracted a lot of attention, in particular the blood serum proteins Human Serum Albumin (HSA) and Transferrin, which are likely to transport uranyl in the body and therefore to play a key role in its toxicity (1-5). It is well known that uranyl undergoes complex speciation at physiological pH, and can form complexes with serum small molecules such as carbonates, making the study of such systems rather intricate. The interaction of uranyl with a protein was studied, while taking into account all known uranyl species that could exist at physiological pH. Bovine Serum Albumin (BSA) is well known to bind several metals, and shares similarities with Human Serum Albumin, which makes it a good candidate for a uranyl-binding protein model. The interaction was followed by means of UV-Visible spectroscopy, circular dichroism and fluorescence measurements (static and time-resolved). Strong fluorescence quenching of the protein was observed upon uranyl addition. Addition of BSA to a uranyl solution also resulted in uranyl fluorescence quenching. The data obtained were treated using speciation software CHEAQS and a fitting program developed in the laboratory. On this experimental basis, the model proposed, involving two successive complexations of several uranyl moieties is in very good agreement with the experimental data. Our results allowed determination of the number of uranyl moieties complexed by the protein, as well as the corresponding equilibrium constants. Further experiments are in progress to determine the functional groups of the proteins involved in the complexation. The experimental protocol and data analysis could be applied to virtually any protein containing enough fluorescent residues to measure the quenching induced by uranyl addition. Further studies with HSA are in progress, and first results will be also presented and compared to the literature (2,6). References 1 Michon J. et al., J. Fluoresc., 2010, 20, 581-590 2 Montavon G. et al., J. Inorg Biochem, 2009, 103, 1609-1616 3 Vidaud C. et al., Biochemistry, 2007, 46, 2215-2226 4 Benavides-Garcia M.G., Balasubramanian K., Chem. Res. Toxicol. 2009, 22, 1613-1621 5 Hémadi et al., J. Phys. Chem. B, 2011, 115, 4206-4215 6 Duff M.R.et al., Angewandte Int. Ed., 2006, 45, 137-139
Speaker: Dr Quentin Raffy (IPHC - Strasbourg University)
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Pb-210 and Po-210 in Some Medicinal Plants
In recent decades, a global trend has been observed in an increased consumption of medicinal plants and herbal formulations, which makes monitoring of herbal medicines to be an actual problem as regards their pollution with heavy metals, pesticides and radionuclides [1]. The highly-toxic are long-lived decay products of U-238 Series, 210Pb and 210Po. In plants, which are used for making medicinal formulations,the 210Po content can be as high as several tens of Bk/kg [2]. The aim of the present work was to determine specific radioactivity of 210Pb and 210Ро in medicinal plants, which are commercially available via the network of pharmacies, and to estimate the effective radiation dose due to 210Ро in humans for a 30-day course of treatment with phyto-teas prepared by infusion from these herbs. Ро-210 in samples and in aqueous extracts were determined by alpha-spectrometry. The samples were digested with a mixture of Н2О2+HNO3(conc.). The aqueous extracts were obtained according to the recommended procedure. 210Ро was quantitatively self-deposited on nickel discs,the remaining solution having been kept for 6 to 8 months for 210Ро to accumulate from 210Pb. After that period 210Ро was deposited again. As a tracer to check chemical yields,a mixture of 208Ро and 209Ро was used. All data are recalculated for the time the samples were made. Six samples were studied. They are: 1. Quercus dalechampii Ten.; 2. Alpinia officinalis L.; 3. Ledum palustre L.; 4. Betula pendula Roth; 5. Plantago major L.; 6. Artemisia absinthium L. Specific radioactivity of 210Pb was from 1.3 (Alpinia officinalis L.) to 18.1 (Ledum palustre L.) Bq/kg d.w. and that of 210Po was from 94 (Betula pendula Roth) to 2257 (Ledum palustre L.) Bq/kg d.w. The 210Ро/210Pb ratio in the samples under study substantially exceeds unity, which means that the origin of 210Ро in there is not related only to radioactive decay of 210Pb. A fraction of the “unsupported” 210Ро is mere 0.2–5.0% of the total amount of the radionuclide, whereas the “unsupported” 210Ро fraction is close to 100%. Analogous results are given in [3]. The obtained data can be explained by a predominant absorption of 210Ро over 210Pb by plants from the environment. For example, it is known that the mean value of the 210Ро/210Pb ratio in air is 0.17, in atmospheric deposits, from 0.1 to 0.54, whereas in soil it is close to 1.0 [4]. The mean annual dose of radiation for the population of the Russian Federation due to 210Pb, 210Po, 228Rа, and 226Rа radionuclides in food and drinking water is estimated to be at a level of 164 µSv/yr [5].The radiation exposure due to 210Ро, which enter the human organism with a daily consumption of 100-300 mL of medicinal plant infusions for 30 days, is from 2 to 21 µSv. It amounts from 1 to 13% of mean annual dose. Based on the above, a conclusion is drawn on that the relative contribution of phyto-teas into the effective annual radiation dose due to Polonium-210 in humans is substantial and should be taken into account. 1.Chan К. Some aspects of toxic contaminants in herbal medicines. Chemosphere,52,2003,1361 – 1371. 2.Desideri D. et al. Natural and artificial radioactivity of some medicinal plants. J. Environ. Radioact.,101,2010,751 – 756. 3.Vaaramaa K. et al. Distribution of 210Pb and 210Po concentrations in wild berries and mushrooms in boreal forest ecosystems. Sci. Total Environ.,408,2009,84 – 91. 4.Parfenov Y. D. Po-210 in the environment and in the human organism. Atomic Energy Rev.,12,1974,75 – 143. 5.Commentaries to Radiation Security Norms (NRB-99-2009). Мoscow, 2009 (in Russian).
Speaker: Dr Natalia Gomzina (N.P.Bekhtereva Institute of the Human Brain, Russian Academy of Sciences (IHB RAS), St. Petersburg, Russia)