Abstract. Part of the process to ensure the safety of radioactive waste disposal is the
predictive modeling of the solubility of all relevant toxic components in a
complex aqueous solution. To ensure the reliability of thermodynamic
equilibrium modeling as well as to facilitate the comparison of such
calculations done by different institutions, it is necessary to create a
mutually accepted thermodynamic reference database. To meet this demand
several institutions in Germany joined efforts and created THEREDA (Moog et
al., 2015). THEREDA is a suite of programs at the base of which resides a relational
databank. Special emphasis is put on thermodynamic data along with suitable
Pitzer coefficients, which enable the calculation of solubilities in
high-saline solutions. Registered users may either download single
thermodynamic data or ready-to-use parameter files for the geochemical
speciation codes PHREEQC, Geochemist's Workbench, CHEMAPP, or TOUGHREACT. Data
can also be downloaded in a generic JSON format to enable the import into
other codes. The database can be accessed via the world wide web:
http://www.thereda.de (last access: 1 November 2021). Prior to release, the released part of the database is subjected to many
tests. Results are compared to results from earlier releases and among the
different codes. This is to ensure that by additions of new and modification
of existing data no adverse side effects on calculations are
caused. Furthermore, our website offers an increasing number of examples for
applications, including graphical representation, which can be filtered by
components of the calculated system.