THEREDA: Thermodynamic reference database

The Thermodynamic Reference Database (THEREDA) is designed for geochemical models in the context of a repository for radioactive waste. The focus is on the correct calculation of the solubilities of radionuclides, fission products and matrix elements (construction materials and mineral phases of the surrounding host rock). However, the ongoing development of THEREDA also takes into account the solubilities of other elements of chemotoxic relevance.

THEREDA especially addresses high-salinity aqueous solutions (brines). For the oceanic salt system, THEREDA is applicable over a temperature range from 0 to 110 °C, and for some subsystems even beyond. This makes THEREDA the only database worldwide that polythermally covers the entire system of oceanic salts, including both acids and bases.

Objectives of the project

In order to generate results that are more easily comparable, the joint THEREDA – Thermodynamic Reference Database – project was initiated in 2006. The thermodynamic data allow estimates regarding the solubility of contaminants and thus conclusions with regard to their mobilisation potential.

THEREDA group

GRS is conducting this project together with the most important research institutions active in the field of radioactive and hazardous chemical waste disposal. The parties involved next to GRS are:

• KIT Institute for Nuclear Waste Disposal (KIT-INE) at the Karlsruhe Research Centre
• Helmholtz-Zentrum Dresden-Rossendorf Institute of Resource Ecology (HZDR-IRE)
• Technische Universität Bergakademie Freiberg Faculty Institute of Inorganic Chemistry (TU-BAF)
• Laboratory for Waste Management of the Nuclear Energy and Safety Research Division of Paul-Scherrer-Institut (PSI-LES)
• CSD INGENIEURE AG (Switzerland)

The project is sponsored by BGE, the German federal company for radioactive waste disposal. It is now already in its fifth phase, which ends in 2029.