Disposal of nuclear waste in host rock formations featuring high-saline solutions – Implementation of a thermodynamic reference database (THEREDA)

Research on the solubility of hazardous substances in saturated salt solutions is an ongoing task in Germany, involving multiple institutions contributing based on their respective expertise. The main objective of this paper is to detail the design of a common thermodynamic reference database (THEREDA), which facilitates the management of thermodynamic equilibrium calculations through the creation of ready-to-use parameter files for widely employed geochemical codes. The methodology includes a comprehensive overview of data tables and interdependencies necessary for the administration of various states, such as aqueous solutions and solids. Key topics addressed in the database structure encompass quality assurance, consistency, traceability, and effective long-term maintenance. Additionally, user-friendly interfaces for both editors and end-users have been implemented, emphasizing robustness and flexibility. Although this paper does not discuss the specific scientific data or model definitions contained within THEREDA, it provides a valuable methodological guide that aids in utilizing thermodynamic data effectively. This implementation can serve as a beneficial template for analogous projects in the realm of waste disposal, transcending beyond the current scope of application.