2Effects of composition and microstructure on oxidation and stress corrosion cracking susceptibility of stainless steel claddings in hydrogenated PWR primary water

Oxidation resistance and stress corrosion cracking (SCC) susceptibility of A508III-309 L/308 L stainless steel (SS) claddings were investigated in simulated pressurized water reactor (PWR) primary water following a microstructure characterization. Preferential oxidation of slip bands was observed in 309 L SS. The oxidation resistance of 309 L SS was found to be lower than that of 308 L SS due to the higher Crand ferrite-content in 308 L SS than in 309 L SS after cladding. There was no indication of SCC for low alloy steel (LAS) after slow strain rate tensile (SSRT) tests. The presence of type-I and type-II boundaries, composition dilution and less delta-ferrite content synergistically contributed to increasing the SCC susceptibility of 309 L SS cladding. The effect of chemical composition and microstructure on SCC performance of the SS claddings was discussed. (C) 2021 Published by Elsevier B.V.

Automated summary

The oxidation resistance of 309L stainless steel was found to be lower than that of 308L stainless steel, leading to increased susceptibility to stress corrosion cracking. The higher Cr and ferrite content in 308L stainless steel contributed to its superior oxidation resistance compared to 309L stainless steel.