Integrated Corrosion Assessment of Copper Canisters for Deep Geological Disposal in Crystalline Rock: A Case Study in Taiwan

This study evaluates the long‐term corrosion of copper canisters in a deep geological disposal repository, focusing on the environmental transition from oxic to anoxic conditions. Utilizing the Features, Events, and Processes (FEPs) framework, we quantitatively analyze physicochemical reactions through mass‐balance and mass‐transport modeling. Initially, corrosion is oxygen‐driven, causing uniform and localized corrosion with an estimated maximum depth of 0.36 mm. As the environment becomes anoxic, sulfide‐induced corrosion dominates, driven by pyrite, sulfate‐reducing bacteria, and groundwater sulfides. Models simulating buffer material erosion and sea‐level fluctuations predict a maximum anoxic corrosion depth of 0.68 mm. After 1 million years, the copper shell retains approximately 48 mm of thickness. We conclude that the canister maintains its integrity as an effective long‐term corrosion barrier.