Publication Details

Category Text Publication
Reference Category Journals
DOI 10.1016/j.jhazmat.2021.127733
Title (Primary) Radionuclide geochemistry evolution in the Long-term In-situ Test (LIT) at Grimsel Test Site (Switzerland)
Author Montoya, V.; Noseck, U.; Mattick, F.; Britz, S.; Blechschmidt, I.; Schäfer, T.
Journal Journal of Hazardous Materials
Year 2022
Department ENVINF
Volume 424, Part D
Page From art. 127733
Language englisch
Topic T5 Future Landscapes
Keywords Grimsel Test Site; Radionuclide speciation; Solubility; Thermodynamic databases; Benchmark; FEBEX bentonite
Abstract The Long-term In-situ Test (LIT) of the Colloid Formation and Migration project (CFM) at the Grimsel Test Site, investigates the generation of bentonite colloids and, hence, radionuclide mobilization within a well-defined and controlled shear zone in a crystalline rock. In this context, the determination of radionuclide aqueous speciation is essential to understand whether radionuclides are easily transported or immobilized by precipitation or uptake processes in the bentonite barrier included in a repository concept for nuclear waste, and mimic in the LIT experiment. The objective of this work is to determine the aqueous speciation of seven radionuclides (i.e. 75Se(VI), 99Tc(VII),233U(VI), 237Np(V), 241Am(III), Th(IV) and 242Pu(IV)) by thermodynamic calculations in different water compositions representing the geochemical evolution through the LIT. A comparison of the results obtained from two different modelling groups allows the identification of the geochemical key parameters affecting radionuclide mobility in this context and the corresponding numerical and conceptual uncertainties. Particularly, silicate complexes of trivalent actinides and uranium(VI) carbonato complexes (i.e. CanUO2(CO3)3(4−2n) n = 1 or 2) seem to be crucial in these environments, even at reducing conditions. Conceptual uncertainties like inclusion/exclusion of tetravalent actinide-bearing colloids formation and polyselenides have clearly been identified.
Persistent UFZ Identifier
Montoya, V., Noseck, U., Mattick, F., Britz, S., Blechschmidt, I., Schäfer, T. (2022):
Radionuclide geochemistry evolution in the Long-term In-situ Test (LIT) at Grimsel Test Site (Switzerland)
J. Hazard. Mater. 424, Part D , art. 127733