Cold Spray Process to Combat Potential Stress Corrosion Cracking in Used Nuclear Fuel Storage Canisters

The cold spray materials deposition process is being investigated for mitigation of chloride-induced stress corrosion cracking (CISCC) in Dry Cask Storage Systems (DCSS) for used nuclear fuel. The welded austenitic stainless-steel canisters in DCSS are under tensile stress and susceptible to environmental chloride corrosion which can potentially lead to the formation of CISCC after long term exposure. The low thermal input and high throughput nature of the cold spray have led to its active consideration as a repair and mitigation approach to combat CISCC. The coatings are under compressive stresses and act as an environmental barrier against a Cl-rich environment. The coatings are demonstrated as a repair process when CISCC is hypothetically present, providing material overlay and deformation of crack tip opening. Thickness, microstructure, adhesion, hardness, and residual stress in the cold spray stainless steel coatings on stainless steel samples with prototypical CISCC will be presented. Gas permeability testing of the cold spray coatings will be also discussed.