Distribution coefficient of radionuclides on rocks for performance assessment of high-level radioactive waste repository

Shibutani, Tomoki; Suyama, Tadahiro*; Shibata, Masahiro 

Distribution coefficients of radionuclides on rocks are selected for safety assessment in the "Second Progress Report on Research and Development for the geological disposal of HLW in Japan (H12 Report)". The categonized types of rock are granitic rocks (crystalline and acidic rocks), basaltic rocks (crystalline and basic rocks), psammitic rocks (neogene sedimentary(soft)), and tuffaceous-pelitic rocks (pre-neogene sedimentary rocks (hard)). The types of groundwater are FRHP (fresh reducing high-pH), FRLP (fresh reducing low-pH), SRHP (saline reducing high-pH), SRLP (saline reducing low-pH), MRNP (mixing reducing neutral-pH) and FOHP (fresh oxidizing high-pH) groundwater. The elements to be surveyed are Ni, Se, Zr, Nb, Tc, Pd, Sn, Cs, Sm, Pb, Ra, Ac, Th, Pa, U, Np, Pu, Am and Cm. Distribution coefficients are collected from literatures describing batch sorption experimental results, and are selected under consideration of conservativity.