Effect of irradiation on the corrosion of 304 stainless steel in pressurized water reactor (PWR) simulated water chemistry.

In this study, the corrosion behavior of pre-ion-irradiated 304 SS is compared to that of un-irradiated 304 SS in simulated Pressurized Water Reactor (PWR) conditions for both early stages of corrosion and longer exposure times. Transmission electron microscopy is used to characterize the oxide scale. The study shows that although the pre-irradiated microstructure does not change the nature of the oxide and its dual-layer structure (i.e. inner/outer oxide layers) formed on 304 SS, the path of growth of the inner oxide layer is affected by the irradiated microstructure resulting in oxide protrusions into the matrix; a mechanism is proposed. • A dual oxide structure forms on 304 SS after corrosion in PWR conditions. • The dual layer shows a continuous Cr-rich inner oxide and Fe-rich oxide islands on the surface. • Pre-irradiation to 10 dpa does not alter the dual-layer oxide structure but affects the inner oxide thickness and shape. • Inner oxide protrusions into the matrix are observed below the bigger oxide particles. • Irradiation loops aligning under local stress and dislocation channels may aid oxygen diffusion. [ABSTRACT FROM AUTHOR]