For the Swiss repository performance assessment concept, a state-of-the-art sorption database (SDB) is needed for different siting regions under investigation. The GEM-Selektor geochemical code is used to interpret the data and compile the SDB for the safety analysis. The Kd values are calculated directly by GEMS, including aqueous speciation, solubility, and concentration-dependent adsorption of each radionuclide for each argillaceous rock/porewater system defined for the different siting regions. The PSI TBD2020 for Nagra, extended with an internally consistent thermodynamic dataset for surface complexation and ion exchange (the updated "ClaySor" version), is also used in the ClaySorDif model extension for the diffusion coefficients of relevant elements
