JAEA thermodynamic database for performance assessment of geological disposal of high-level radioactive and TRU wastes; Fundamental plan and status of selection of thermodynamic data

Kitamura, Akira  ; Fujiwara, Kenso ; Shibata, Masahiro ; Tachi, Yukio  ; Doi, Reisuke  ; Yoshida, Yasushi*; Yamaguchi, Tetsuji ; Yui, Mikazu

A fundamental plan has been established to develop a thermodynamic database for performance assessment of geological disposal of high-level and TRU radioactive wastes. Number of selected elements is 24 (actinides, fission products and their daughters), which are of importance for the performance assessment of geological disposal. The fundamental plan is in principle based on the guidelines established by the Nuclear Energy Agency in the Organization for Economic Co-operation and Development (OECD/NEA). Additional unique guidelines have been established due to a requirement from the performance assessment to select tentative thermodynamic values obtained from chemical analogues and/or models for some elements of which thermodynamic values are insufficient. Status on selection of thermodynamic data of cobalt, nickel and palladium has been introduced as well as the fundamental plan.