PSI/Nagra Chemical Thermodynamic Database/TDB 2020
The PSI/Nagra Thermodynamic database project supports the ongoing safety assessments for the planned repositories for low- and intermediate-level (L/ILW) and high-level (HLW) radioactive waste in Switzerland. Based on thorough critical review of experimental data, following the Nuclear Energy Agency (NEA) guidelines, several updates to the database have been released. The data evaluation procedures and the selection of values are documented in all steps to maximize traceability. The latest version, TBD 2020, is an update from the Paul Scherrer Institute PSI/Nagra TBD 12/07 PDF, published in 2014, and its predecessor Nagra/PSI TDB 01/01, published in 2002. Older documentation on core data for aqueous species, minerals, and gases of elements commonly found in natural waters can be found in Nagra/PSI TDB 1992 with supplementary material.
The database has a wide range of applications beyond radionuclides, as it can be utilized to model various systems of interest in environmental geochemistry.
The TDB 2020 includes thermodynamic data for 53 elements, 1'034 aqueous species (and SIT ion interaction coefficients for all species), 358 solids and 8 gases. For the application of SIT to environmental systems where salinity is governed by NaCl, an estimation method has been developed to fill the numerous gaps in the set of experimentally determined SIT coefficients in NaCl background media.
The PSI/Nagra Chemical Thermodynamic Database 12/07 is the default database for GEMS-PSI. A preliminary variant of the PSI/Nagra TDB2020 database valid for 1 bar 25 C is available in GEMS format and is used for the preparation of the solubility and sorption databases for the RBG. Work is under way to extend the GEMS PSI/Nagra TDB2020 database with temperature (pressure) dependence and molar volumes for solids.
The TDB 2020 (with a complete SIT interaction parameters set) is available for download to be used in different geochemical modeling codes:
Download Geochemist's Workbench version (to avoid possible issues, change the file ending from .txt to .tdat)
Where a complete set of enthalpy values (and sometimes also heat capacities) is available for compounds and complexes involving OH-, F-, HCO3-, CO3-2, SO4-2 and Li, Na, K, Mg, Ca, Sr, Ba, Ra, Mn, Al, the database can also be used for calculations at elevated temperatures (based on the 2- and 3-term extrapolation method).
The TDB 2020 includes new reviews for the elements Ac, Ag, Cd, Cf, Cu, Hg, Ho, Pa, Pb, Po, Sm, Ti and Zn, and updates of previous data for Al, alkali (Li, Na, K) and alkaline earth elements (Mg, Ca, Sr, Ba, Ra), Am, Eu, Fe, Mn, Mo, Nb, Np, organic ligands, Pd, Pu, S, Se, silicates, Sn, Tc and U. Data for Ni, Th and Zr, included in PSI/Nagra TBD 12/07 PDF based on NEA TDB reviews remain essentially unchanged.
A PHREEQC-version (only log K values, Davies equation) of PSI/Nagra TBD 12/07 PDF is also available for download:
Right-click to download version with mac or unix line feeds
Right-click to download version with windows line feeds