Corrosion of 316L stainless steel in high temperature water and steam: effects of simultaneous proton irradiation

316L stainless steel was exposed to 320 degrees C hydrogenated water and 480 degrees C hydrogenated steam for 24 h and 72 h while simultaneously irradiated with 5.4 MeV protons to yield a damage rate of 7 x 10-7 dpa/s. Oxide films characterized in cross-section STEM revealed chemical and morphological differences. High levels of radiolysis in water resulted in significantly reduced corrosion rates while inducing dissolution of the inner oxide layer, whereas in steam the effects of radiolysis are insignificant. Conversely, displacement damage effects are negligible in water but significantly increase the corrosion rate in the steam condition through the growth of inner oxide porosity.