Technical Note: Corrosion Behavior of 316 Stainless Steel With and Without an Ni Coating in Solid-State Fluoride Salt

With the rapid development of molten salt reactors, the problem of post-treatment of spent fuel salt discharged from the core becomes increasingly prominent. Like molten fluoride salts, solid fluoride salts are also highly corrosive, which poses a serious challenge to container materials. This paper describes the corrosion behavior of 316 stainless steel (316 SS) with and without Ni coating in low-temperature solid fluoride salt. Results show that 316 SS without Ni coating experiences pitting corrosion with the prolongation of corrosion time. 316 SS with Ni coating experiences intergranular corrosion. In addition, a loose hollow interlayer is formed between Ni coating and matrix. Corrosion of both samples increases with the extension of exposure time with solid fluoride salts.