Use of an experimental sorption database for predicting the sorption of Cs, Np, Th, and Se under projected URL-conditions

Ochs, M.*; Kunze, S.*; Yui, Mikazu; Sasamoto, Hiroshi   

JAEA has been developing generic methodologies using the generic type of underground research laboratory (URL). In order to develop a practical method for mass transport analysis, it is important to evaluate the application of method to an actual geological environment. Kd is the one of important parameter for mass transport analysis, thus the present study discusses the practical method to derive the Kd for some important radionuclides at the environment of Horonobe URL using the sorption database. As a first step, the present study has been conducted (1) to design the experimental program to be conducted in the Horonobe URL, and to (2) test the usefulness of and identify important gaps in the existing database. The sorption database was applied to an initial prediction of the sorption of Cs, Np, Th, and Se under expected URL-conditions. Kd-derivation was done using the estimation methods discussed in Ochs et al, (2006). This preliminary exercise in Kd-setting allowed to estimate the magnitude of sorption under the expected in-situ conditions. More importantly, it also allowed to identify critical gaps in the existing database and process understanding.