13-18 May 2018
Casino Conference Centre
Europe/Prague timezone

Profile analysis of Aare granite samples after radionuclide migration

17 May 2018, 09:15
15m
Marble Hall (Casino Conference Centre)

Marble Hall

Casino Conference Centre

Reitenbergerova 4/95, Mariánské Lázně, Czech Republic
Verbal Chemistry of Nuclear Fuel Cycle, Radiochemical Problems in Nuclear Waste Management NFC 4

Speaker

Ms Eva Hofmanová (Fuel Cycle Chemistry Department, ÚJV Řež, Czech Republic)

Description

Several laboratory through-diffusion experiments with HTO, 36Cl, selenate, 22Na, 85Sr, 134Cs, and 133Ba were performed on samples from experimental and monitoring borehole of the Long Term Diffusion Phase III experiment in Grimsel Test Site. Salinity dependent cation excess and anion exclusion effects were observed. Anion effective diffusivities were almost half of water effective diffusivity. Na and Sr effective diffusivities were 1.5 and 5.5 times higher than water effective diffusivity, respectively. Heterogeneous character of granite diffusion path was observed experimenting with Cs and Ba.
Using numerical modeling, unknown parameters of porosity, geometrical factor, and distribution coefficient can be evaluated from the break-through and depletion curves. The associated uncertainty of diffusion parameters might be thus significant. It might be reduced by obtaining tracer concentration profile in the rock sample. We applied two experimental procedures for profile analysis. The first consisted in sawing the sample on thin slices using Struers Secotom Hot Cell saw and diamond cut-off wheel. The second procedure was an abrasive technique commonly used for cementitious materials and argillaceous rocks. Instead of grinding paper, artificial corundum (Al2O3:B80 and Al2O3:B150) mixed with cooling water was used. Benefits and drawbacks of both methodologies will be discussed. The profit of having the concentration profile, as the third dataset from the through-diffusion experiments, will be demonstrated, presenting Na, Sr, and Cs experiments.

Acknowledgment:
The research in LTD Phase III was funded by SURAO.

Primary authors

Ms Eva Hofmanová (Fuel Cycle Chemistry Department, ÚJV Řež, Czech Republic) Mr Tomáš Rosendorf (CTU in Prague / ÚJV Řež, a. s.) Dr Milan Zuna (Fuel Cycle Chemistry Department, ÚJV Řež, Czech Republic) Mrs Vaclava Havlova (UJV Rez, a.s.) Dr Ondrej Srba (Material and Mechanical Properties, Research Centre Řež, Czech Republic)

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