Predicting Corrosion and Enhancing Lifetime of Nuclear Dry Storage Canisters

Abstract

Nuclear technology for power generation provides a cleaner, environmentally friendly source of energy, and is more reliable than solar or wind energy. However, the used nuclear fuel rods require periodic replacement which, unlike wind and solar energy, also requires safe storage because they are still hot and radioactive. In the USA, safe storage of used nuclear fuel relies mainly on interim dry cask storage systems. The absence of a permanent safe storage strategy, such as a geologic repository puts an unexpected strain on the dry storage canister (DSC) encasing the used nuclear fuel, which must last for 50 years or longer - a particularly difficult problem for power stations located in coastal areas. As these containers cool after long exposure time corrosion such as galvanic, pitting, and stress corrosion cracking might set in and cause weld and other failures, leading to leakage. The challenge therefore, is how to protect the DSC welds from corrosion and be sure that the protection will last their required lifespan. We have investigated electrochemically and computationally the likelihood of corrosion in a DSC system, have evaluated a technology that may be used to extend their protection, and briefly discussed the findings.