Corrosion effect of Fe- and Ni-based alloys for molten salt reactors according to additional trivalent salt

Abstract

The objective of this study is to find an alloy with excellent corrosion resistance that can be used as a structural material for molten salt reactors (MSRs). For this purpose, a corrosion test is conducted using Fe- and Ni-based alloys with different Mo and Cr contents in a chlorine-based molten salt. The corrosion behaviors of 316L stainless steel (SUS316L), Hastelloy C-276, and Hastelloy N are compared by conducting an accelerated experiment at a temperature higher than the operating temperature of the MSR in the presence of oxygen, moisture, and Cl- ions. SUS316L, which has a low Mo content, exhibits corrosion along the grain boundaries, whereas Hastelloy N, which has a low Cr content, exhibits corrosion on the surface. Hastelloy C-276, which has high Cr and Mo contents, exhibits a lower corrosion depth and weight loss rate compared with the other samples. The results reveal that corrosion in a chloride environment depends on the Cr and Mo contents.