Geochemistry

Geochemical processes are very important for the storage of radioactive waste in deep geological repositories. The chemical composition of host rock and groundwater is the subject of many investigations. Influences of the construction and operation of a repository on geochemistry are clarified in rock laboratory experiments. As part of its long-term cooperation with Nagra and Andra (Agence national pour la gestion des déchets radioactifs, France), Solexperts developed new instrumentation and experimental techniques for in-situ geochemical experiments.

ANDRA Rock Laboratory CMHM Bure: Corrosion Experiments (MCO 2008 - 2017)

Radioactive waste containers interact with the groundwater of the host rock. One of these interactions is the corrosion of the steel containers and the associated gas production. Solexperts, together with the CEA (Commissariat à l'énergie atomique, France), has developed the following new in-situ testing techniques:

Sampling under in-situ conditions
Measurement of the corrosion rate of different metal samples on-site in the borehole
Measurement of dissolved gases in groundwater and gas production due to corrosion

ANDRA, NAGRA, SCK/CEN Mont Terri Rock Laboratory: Diffusion experiments (1997 - 2025)

Diffusion coupled with sorption on clay minerals dominates the transport of radionuclides in the very low pemeable Opalinus Clay. Solexperts first developed an experimental setup for in-situ diffusion experiments in 1997 and successfully implemented it in the Mont Terri DI-experiment. Afterwards, the same experimental concept was used for many follow-up experiments. In the current in-situ diffusion experiment (DR-C experiment) in the Mont Terri rock laboratory, the influence of increased temperature on the transport of radionuclides is investigated.