Performance of the new ferritic/martensitic steel SIMP against liquid lead‐bismuth eutectic corrosion: Comparison with T91 and 316L steels

Abstract The degradation of structural materials caused by the corrosion of liquid lead‐bismuth eutectic (LBE), the coolant of lead‐cooled fast reactors (LFRs), has become one of the limiting factors for the development of LFRs. In this study, LFR structural candidates SIMP and T91 ferritic/martensitic steels and 316L austenitic stainless steel were selected to conduct corrosion experiments at different durations (120–1218 h) in oxygen‐saturated liquid LBE at 550°C. It was found that the austenitic stainless steel 316L has the best resistance to LBE corrosion due to its high Cr content, which allows dense Fe–Cr spinel with high Cr content to be generated in oxygen‐containing LBE, slowing down the oxidation rate. However, a certain degree of dissolution corrosion occurred in the early stages of corrosion in 316L steel, which disappeared with the increase of time. The ferritic/martensitic steel SIMP has better oxidation resistance than T91 due to its higher Si content, which results in a more compact inner oxide layer of SIMP steel, thus impeding the diffusion of Fe and O ions more effectively.