Simultaneous irradiation and oxidation/corrosion is known to affect the grain boundary properties of 316L stainless steel materials. Defects formed during irradiation can affect the diffusion of oxygen and thereby potentially enhance preferential GB oxidation. The stress concentration at the weakened GBs may furthermore significantly enhance grain boundary cracking.
In this project the effect of proton irradiation, cold work, and different heat treatments on the oxidation of 316L stainless steel was studied in long term exposure tests under simulated PWR primary cooling wa-ter conditions using unloaded coupon specimens as well as specimens passively loaded to different load levels by four point bending. After long term exposure tests extensive investigations on grain boundary oxidation and cracking were performed on a constantly loaded specimen and on a specimen after repeated loading/unloading.
The time dependent evolution of the grain boundary oxidation data is further correlated to internal oxi-dation models and their application to austenitic stainless steels.