Investigation of Cold Spray Performance for Cleaning and Repair of Dry Cask Storage System (DCSS) Canisters within a Characteristic Confinement

Extended storage of spent nuclear fuel (SNF) in intermediate dry cask storage systems (DCSS) due to lack of permanent repositories is one of the key issues for sustainability of the current domestic Light Water Reactor (LWR) fleet. The stainless-steel canisters used for storage in DCSS may be susceptible to chloride-induced stress corrosion cracking (CISCC) due to a combination of tensile stresses and susceptible microstructure from the welds, and a corrosive chloride salt environment. This research assesses the viability of the cold spray process as a solution to CISCC in DCSS when sprayed within a characteristic overpack in two different capacities: cleaning and coating. In general, the cold spray process uses pressurized and preheated inert gas to propel powders at supersonic velocities, while remaining solid-state. Further, cold spray cleaning is an economical, non-deposition process that leverages the mechanical force of the propelled powders to remove dust and/or corrosion buildup on the canister. The cold spray coating process uses augmented parameters to deposit a coating that looks to repair CISCC on the canister surface. Moreover, both processes have the potential to induce a surface compressive residual stress that is known to mitigate the initiation of CISCC. Surface morphology, deposition analysis, and microstructural developments in the near-surface region were examined. Additionally residual stress measurements and cyclic corrosion testing (CCT) were conducted to elucidate the influence of cold spray cleaning and coating on corrosion performance.