Protection of the Steel Used for Dry Cask Storage System from Atmospheric Corrosion by Tio2 Coating

Austenitic 304 stainless steels (SS) and carbon steels (CS) are widely used as structural materials for components and pipe assemblies in nuclear power plants. Steels also act as the important canister materials in the dry storage of spent nuclear fuels. However, it is well known that stainless steels and carbon steels are susceptible to stress corrosion cracking (SCC) in certain environments induced by sea salt particles and chlorides. It is known that the TiO2 coating acts as a non-sacrificial anode and protects the steel cathodically under UV illumination. In this study, the photoelectrochemical behavior of the steel with TiO2 coating by sol-gel method was investigated to mitigate atmospheric SCC. In addition, the slow decline of photovoltage of the samples coated with TiO2 after UV illumination have been studied. These results indicate that the TiO2 treatment with or after UV illumination would effectively reduce the steel corrosion rate in atmospheric environments.