Development of fully-coupled thermo-hydro-chemical(THC) model for predicting copper canister corrosion behavior

Abstract

Although the nuclear energy has given lots of conveniences, they cause used nuclear fuel inevitably. Since the used nuclear fuels are high-level radioactive waste, they must be isolated from an ecosystem. To dispose the used nuclear fuel at the deep geological repository, in Korea, the multi-barrier concept developed by Sweden and Finland has been considered. The multi-barrier concept consists of iron insert, copper canister, and buffer material. Among them, the objective of copper canister withstands corrosion load induced by dissolved chemical species(O2, HS-, Cl-, etc.). Since the integrity of deep geological disposal is affected by copper canister corrosion, the investigation of copper in deep geological environment must be conducted. Therefore, in this study, the thermo-hydro-chemical model was developed by using finite element method. As a result, the result of temperature and water saturation, and corrosion depths showed reasonable results compared with existing models