Testing coatings to conserve canisters against corrosion

As anyone who has lived near the ocean can attest, metal and sea mist are a recipe for corrosion. A nuisance of coastal life, the consequences of these common chemical reactions become far more serious when it is taking aim at the stainless-steel canisters that contain spent nuclear fuel.

To shield steel from the corrosive threats posed by sea air, Sandia National Laboratories researchers tested a variety of nickel mixtures as protective coatings on stainless steel. The researchers found that the specific material applied, and the specific application process used, impacted the properties of the coating, including how protective it was against corrosion. Their results were published recently in the scientific journal Frontiers in Metals and Alloys.

Spent nuclear fuel is stored in quite a few coastal areas, where sea breezes can buffet canisters and deposit corrosive chloride salts such as sodium chloride, or more commonly known as table salt. Given enough time, the brine formed by these salts can corrode and pit stainless-steel canisters.

“Through our research, it became clear that it would not be easy to completely eliminate the possibility of a type of corrosion known as stress corrosion cracking,” said Charles Bryan, an expert on the storage of spent nuclear fuel and co-lead on the project. “Stress corrosion cracking is likely to eventually occur at some interim storage sites. It might take hundreds of years, but it could happen, so people started thinking about mitigation and repair technologies. We started looking at cold spray, which is a technique industry is very interested in, and at corrosion-resistant polymer coatings.”

Read the complete news release.

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