Establishment of data base files of thermodynamic data developed by OECD/NEA. Part 4. Addition of thermodynamic data for iron, tin and thorium

Thermodynamic data for compounds and complexes of elements with auxiliary species specialized in modeling requirements for safety assessments of radioactive waste disposal systems have been developed by the Thermochemical Data Base (TDB) project of the Nuclear Energy Agency in the Organization for Economic Co-operation and Development (OECD/NEA). Recently, thermodynamic data for aqueous complexes, solids and gases of thorium, tin and iron (Part 1) have been published in 2008, 2012 and 2013, respectively. These thermodynamic data have been selected on the basis of NEA's guidelines which describe peer review and data selection, extrapolation to zero ionic strength, assignment of uncertainty, and temperature correction; therefore the selected data are considered to be reliable. The reliability of selected thermodynamic data of TDB developed by Japan Atomic Energy Agency (JAEA-TDB) has been confirmed by comparing with selected data by the NEA. For this comparison, text files of the selected data on some geochemical calculation programs are required. In the present report, the database files for the NEA's TDB with addition of selected data for iron, tin and thorium to the previous files have been established for use of PHREEQC, Geochemist's Workbench and EQ3/6. In addition, as an example of confirmation of quality, dominant species in iron TDB were compared in Eh-pH diagram and differences between JAEA-TDB and NEA-TDB were shown. Data base files established in the present study will be at the Website of thermodynamic, sorption and diffusion database in JAEA (http://migrationdb.jaea.go.jp/). A CD-ROM is attached as an appendix. (J.P.N.)