Corrosion lifetime assessment for candidate materials of high-level radioactive waste overpack for geologic disposal

Present and future Ishikawajima-Harima Heavy Industries (IHI) research on the integrity assessment of the overpack to be used for the geologic disposal of high-level radioactive waste are discussed. For mild steel, a prediction model for the maximum penetration depth based on data for average penetration depth in the general corrosion domain has been developed, for the passivity/localized corrosion domain, the possibility of initiating crevice corrosion is now recognized. For titanium alloys, assessment of critical conditions and collection of lifetime distribution data on initiation of crevice corrosion are progressing well. (author)