Insight into the long-term corrosion evolution of borated stainless steels in the wet storage environment for spent nuclear fuel.

Long-term corrosion evolution of boron-containing stainless-steel (BSS) in simulated environment of spent nuclear fuel wet storage is investigated. Corrosion evolution goes through three phases of rising, stabilization and declining, which corresponds to five electrochemical processes. As B content increases, the initiation and stable growth of pits are promoted by decreased Cr ox 3+ and increased inhomogeneity of passive film and enhanced micro-galvanic effect, resulting in reduced |Z| 10mHz value and the duration of the second stage. Due to reduced grain sizes, the corrosion resistance of hot-rolled BSS is substantially improved with homogeneous passive film, higher Cr ox 3+ in it and weaker micro-galvanic effect. • Long-term corrosion of BSSs in SNF wet storage environment was investigated. • Corrosion evolution for BSS exhibited three distinct stages based on in-situ EIS. • Long-term corrosion resistance of the BSSs was significantly improved by hot-rolling treatment. [ABSTRACT FROM AUTHOR]