Cracking of canisters or a crack that grows through the wall are not plausible scenarios. As part of the NRC’s license renewal, the inspection and aging management program requires surface inspections of canisters. If an issue were identified, there would be sufficient time to act, since corrosion is a very slow process. If any crack were to form, it would be detected as part of the inspection program before it could ever go through the wall of the canister. Chloride Induced Stress Corrosion Cracking (CISCC) has been identified as a potential mechanism of a long-term degradation, particularly in a marine environment, and the nuclear industry takes several precautions to prevent any degradation issues. Manufacturing techniques such as the reduced amount of welding needed on the canister and less heat from the welding process, and a robust inspection program are among the actions in place to mitigate CISC.
