Update of JAEA-TDB; Update of thermodynamic data for palladium and tin, refinement of thermodynamic data for protactinium, and preparation of PHREEQC database for use of the Brnsted-Guggenheim-Scatchard model

Kitamura, Akira  ; Doi, Reisuke  ; Yoshida, Yasushi*

The latest available thermodynamic data for palladium and tin were critically reviewed and the selected values were included into the JAEA-TDB for performance assessment calculations for geological disposal of radioactive high-level and TRU wastes. We made sure that the selected data are internally consistent with other data included in the compilation. This critical review specifically addressed thermodynamic data for (1) the palladium-hydroxide-chloride system, and (2) the solid oxides and hydroxido complexes of Sn(IV). We also selected thermodynamic data for other tin reactions from critical review of tin by the Nuclear Energy Agency of the Organisation for Economic Co-operation and Development (OECD/NEA). Furthermore, we refined some thermodynamic data for protactinium to estimate more reliable solubility values. We prepared text files of the updated thermodynamic database (JAEA-TDB) for geochemical calculation programs of PHREEQC, EQ3/6 and Geochemist's Workbench. Use of the Brnsted-Guggenheim-Scatchard Model (SIT) for ionic strength corrections was applied to the PHREEQC database.