Studying the relevance of mechanical process to the geochemical evolution in bentonite buffer of repositories for high-level radioactive waste

Abstract

In deep geological repositories for high-level radioactive waste, the bentonite buffer undergoes thermal, hydrological, mechanical, and chemical (THMC) processes. This study aims to clarify the significance of the mechanical process in the THC evolution of bentonite by comparing a THC model with a coupled THMC model for a generic repository. The comparison shows that the impact of the mechanical process on hydrological and geochemical changes is significant during the early unsaturated stage but diminishes in the later stages once the bentonite is fully saturated. This suggests that considering mechanical processes may not be essential for long-term radionuclide migration models.