Evaluation of gamma radiation-induced corrosion depth of Cu canister in high-efficiency deep geological repository system for CANDU spent nuclear fuel

This study presents a model for predicting the gamma radiation-induced corrosion depth of copper (Cu) canisters intended for deep geological repositories. Three predictive methods were implemented and validated against data from the existing literature. The methods were then used to evaluate copper canisters designed for CANDU spent nuclear fuel of varying thicknesses (3, 10, 20, 30, 40, and 50 mm) at pH levels of 7, 8, 9, and 10. The results indicate that while all tested thicknesses demonstrate sufficient resistance to radiation-induced corrosion, the 3 mm canister warrants caution due to a projected corrosion depth of approximately 8% of its total thickness. Furthermore, the study finds that the influence of the hydroxyl radical (OH·) on long-term corrosion may be negligible over a one-million-year period under the studied conditions. This suggests that future gamma radiation-induced corrosion models may be simplified. • Low-burnup fuel causes greater long-term radiation-induced corrosion • OH radical does not show significant contribution to radiation-induced corrosion • 10-50 mm Cu thickness show quite robust resistance to radiation-induced corrosion