Recent developments in ThermoChimie – A thermodynamic database used in radioactive waste management

• Published in: Applied geochemistry Vol. 180; p. 106273
• Main Authors: Madé, B., Bower, W., Brassinnes, S., Colàs, E., Duro, L., Blanc, P., Lassin, A., Harvey, L., Begg, J.D.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.02.2025; Elsevier
• Subjects: Belgium; Earth Sciences; France; geochemistry; radioactive waste; research and development; Sciences of the Universe; thermodynamics; waste management; Belgium; France
• ISSN: 0883-2927
• DOI: 10.1016/j.apgeochem.2024.106273

ThermoChimie is a thermodynamic database project intended for use across the radioactive waste management community to support repository performance assessment, research and development activities, and potentially inform decisions about waste conditioning, reprocessing, and disposability. Established in 1995 by Andra (France), and now managed by a consortium that also includes NWS (UK) and ONDRAF/NIRAS (Belgium), it is currently moving towards the end of Phase 3 (December 2025) of the project with the recent release of ThermoChimie version 12a and a further version update anticipated in the next 18 months. This paper provides an overview of the ThermoChimie database with emphasis on the activities undertaken during Phase 3, including major updates of the Pd, Fe, Se, Ni, U, Np, Pu, Am, Cm, and Tc systems, inclusion of data for Cu, Be, and Hg, the further development of the XCheck© tool that facilitates database management, increased database compatibility with a range of geochemical codes (PHREEQC, TOUGHREACT, CrunchFlow, CHESS, GWB, Spana, PFLOTRAN), and expert consultation on the subjects of cement and zeolite phases and redox reactions to inform future development of the database. This considerable body of work ensures that the ThermoChimie database continues to provide accurate, consistent and complete (as far as practicable) thermodynamic data to the radioactive waste community and beyond. •ThermoChimie (TC) is a thermodynamic database for use across the radioactive waste management community.•TC Phase 3 (2018–2023) has seen addition of Be, Cu, and Hg and comprehensive update of Fe, U, Pu, Np, Am, Cm, and Tc systems.•Version 12a of the database was made available in 2023.•Version 12a has compatibility with PHREEQC, TOUGHREACT, CrunchFlow, CHESS, GWB, Spana, and PFLOTRAN.•Phase 3 now extended to end of 2025.