| Abstract Scope |
Nanoengineered powder-metallurgy austenitic stainless steels are emerging as promising replacements for conventional alloys used in reactor core internals to mitigate irradiation-assisted stress corrosion cracking (IASCC). In this study, Type 304 SS, including oxide-dispersion-strengthened steel (ODS) fabricated by spark plasma sintering and ultra-fine-grained (UFG) steel produced by equal channel angular pressing, along with conventional 304 SS, were proton-irradiated to 5 dpa and subsequently strained in a pressurized water reactor (PWR) environment at 320°C. Crack initiation behavior was evaluated using four-point bend testing. Both nanoengineered alloys exhibited superior IASCC resistance, as no dislocation channels or oxidized grain boundaries were observed below the yield strength, and no cracks were detected up to the yield strength, typically not approached under normal reactor core service. These results indicate suppression of irradiation-induced deformation and grain-boundary oxidation, demonstrating the potential of ODS and UFG 304 SS for enhanced IASCC resistance in PWR core components |