Speaker
Description
Closing the fuel cycle to promote a safe and sustainable nuclear energy requires capabilities to reprocess and multi-recycle U but also major (Pu) and minor actinides (MA: Am, Cm, Np) into new fuels for advanced reactors. Nowadays, the hydrometallurgical processes are the most mature technology able to address actinides recycling within this context, although they are not exempt of important challenges. For example, one of the keys for the development of new and advanced processes requires designing highly selective extraction systems but also to deal with their degradation and regeneration due to the effect of the strongly radiative field and nitric acid concentration where nuclear fuel must be dissolved [1]. In that sense, the objective is not perfect resistance to the aggressive medium, but sufficient for a safe and efficient industrial implementation of the processes. Within this framework, diglycolamides (DGA) are considered as one of the most promising extractants for lanthanides and actinides, and currently engaged in many advanced separation strategies. During the past decades, it has been acquired a lot of knowledge and experience about the stability of DGA based-solvent, and particularly about TODGA (N,N,N´,N´-tetraoctyldiglycolamide), being very revealing the studies exploring the individual properties of degradation compounds and their correlation with the behavior of the system after irradiation [2-5].
In an effort to increase the ability to predict the evolution and performance of these new extracting systems against radiation, the trend in our stability studies is moving toward deepest evaluation of the composition in the long term and a more integrated exploration of robustness, designing more realistic experiments that mimic the solvent degradation. This work summarizes our latest studies conducted for a better understanding of the effects and implications of TODGA radiolytic degradation compounds on actinides partitioning processes.
[1] P. Baron, S. Cornet, E. Collins, G. DeAngelis, G. Del Cul, Y. Fedorov, J. Glatz, V. Ignatiev, T. Inoue, and A. Khaperskaya, "A review of separation processes proposed for advanced fuel cycles based on technology readiness level assessments," Progress in Nuclear Energy, vol. 117, p. 103091, 2019.
[2] H. Galán, A. Núñez, A. G. Espartero, R. Sedano, A. Durana, and J. de Mendoza, "Radiolytic stability of TODGA: characterization of degraded samples under different experimental conditions," Procedia Chemistry, vol. 7, pp. 195-201, 2012.
[3] I. Sánchez-García, H. Galán, J. M. Perlado, and J. Cobos, "Stability studies of GANEX system under different irradiation conditions," EPJ Nuclear Sciences & Technologies, vol. 5, p. 19, 2019.
[4] Y. Sugo, Y. Sasaki, and S. Tachimori, "Studies on hydrolysis and radiolysis of N, N, N′, N′-tetraoctyl-3-oxapentane-1, 5-diamide," Radiochimica Acta, vol. 90, pp. 161-165, 2002.
[5] C. A. Zarzana, G. S. Groenewold, B. J. Mincher, S. P. Mezyk, A. Wilden, H. Schmidt, G. Modolo, J. F. Wishart, and A. R. Cook, "A comparison of the γ-radiolysis of TODGA and T (EH) DGA using UHPLC-ESI-MS analysis," Solvent Extraction and Ion Exchange, vol. 33, pp. 431-447, 2015.