Effect of pre-oxidation on radiation-induced corrosion of Cu canister for deep geological repository

Abstract

Some amount of initial Cu oxide always presented on the Cu canister and significantly affect to the radiation-induced corrosion of Cu in a deep geological repository. Therefore, this study aimed to figure out the effect of initial amount of Cu oxide to radiation-induced corrosion of Cu for de-aerated ultrapure water which is a generic deep geological repository condition. Two different amounts of initial Cu oxide on Cu samples were irradiated in de-aerated ultrapure water by gamma cell (137Cs, ~0.2 Gy/s). The oxidized Cu on Cu samples and in water were measured by cathodic reduction method and ICP-OES. Numerical modeling was developed base on COMSOL and simulated the most corroded Cu sample case in the experiment. The measured amount of oxidized Cu and result of numerical modeling showed O2 was major oxidant species and a penetration depth of Cu was 37.44 nm which is 105-106 smaller than realist Cu thickness of Cu canister.