Extending the Service Life of Nuclear Waste Storage Units via High-Pressure Cold Spray Coatings

The storage of spent nuclear fuel (SNF) is one major concern in the expanding utilization of nuclear energy. SNF is often stored in dry canister storage systems (DCSS), 90% of which use welded canisters made of 304 or 316 stainless steels. These systems were initially meant for temporary storage before final disposal, however; DCSS are currently being used for extended periods with many plants seeking extensions of multiple decades for licenses on these systems. The stainless steels used in current storage methods are susceptible to chloride induced stress corrosion cracking (CISCC). This increases the potential of a crack developing, compromising the integrity of the canister. VRC Metal Systems, LLC (VRC) proposes utilizing High-Pressure Cold Spray (HPCS) for reinforcement of spent nuclear fuel (SNF) cannisters for the mitigation of CISCC in cannister weld regions. The study will evaluate CISCC in current storage systems in comparison to HPCS reinforcement, with a focus on the comparing compressive residual stresses of the coatings to the tensile residual stresses in the welds. Evaluate open literature and select candidate materials for cold spray processing based on their corrosion/oxidation resistance at elevated temperatures. Produce several powder blend materials for cold spray processing: evaluating the thermal history of the substrate during spray. Optimize cold spray materials and processing parameters for reinforcement and protection of 304/316 stainless steel cannister welds. Evaluate the mechanical properties of the cold spray coatings and weld regions. Evaluate and compare the corrosion resistance of the cold spray coatings and the weld regions Cold spray is a unique metal deposition and spray technology that is changing the way we think about coatings and repair across a very wide range of industries. The primary groups benefiting from the proposed work are the US Department of Energy (DoE) and facilities which store SNF. However, the market for the proposed work extends far beyond this, providing benefits across the manufacturing spectrum. A deposition method that can viably mitigate or repair damage from CISCC will be viable in many other industries including other renewable energy fields, conventional energy fields, automotive, aerospace, and many other industries. There is a great need to disseminate the knowledge base currently available through education and training, as well as to continue to conduct research and development on this important technology.