Effects of irradiation on the corrosion of structuralmaterials are poorly understood, especially radiolysisfrom high LET particles such as ions. Effects of radiolysison corrosion of 316L stainless steel were studied using aproton beam passing through 320˚C high purity watercontaining 3 wppm H2 in a direction parallel to the samplesurface. The 316L was pre-treated by solution annealing at1050˚°C for 30 min, 5% cold work, and heat treating at1100°C for 10 min; this resulted in 23 μm grains. Protonirradiation was conducted for 24 hours and generated adose rate range in water from 700 kGy/s at the cellentrance to 1500 kGy/s at the dose peak. Oxide thicknessand composition were measured from cross-sectional TEMlamella prepared by FIB using HAADF STEM and STEMEDS.In all areas the oxide exhibited a standard duplexstructure with individual outer oxide particles and an inneroxide with non-uniform thickness. The thickness decreaseddramatically under proton radiolysis but was uniform overthe dose rate range examined. Beyond the proton range,the thickness increased gradually with distance to typicalvalues for non-irradiated oxide. A thin layer of the inneroxide adjacent to the metal was observed to be morechromium enriched than non-irradiated oxides resulting indecreased oxide thickness.
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