Effects of gamma-ray irradiation on crevice corrosion repassivation potential of stainless steel in high temperature diluted simulated seawater

The crevice corrosion repassivation potentials (ER,CREV) of type 304 stainless steel (304 SS) were measured in high temperature (373–553 K), diluted simulated seawater under gamma-ray irradiation, in order to confirm the effects of gamma-ray irradiation on the crevice corrosion behavior of a representative stainless steel in seawater. Overall, for high temperatures, the ER,CREV values decreased with increasing chloride ion concentration, which was the same as the behavior observed under the non-irradiated condition. The ER,CREV values measured under gamma-ray irradiation were the same or slightly higher than ER,CREV values measured under the non-irradiated condition when the [Cl−] was the same. Consequently, it was confirmed that the threshold potential of crevice corrosion of 304 SS for the gamma-ray irradiation of 1.8 kGy at least did not deteriorate compared with the non-irradiated condition. Under the conditions of this work (seawater composition, [Cl−] range, dose rate, absorbed dose, flow rate, etc.), the crevice corrosion of 304 SS could be suppressed by maintaining the potential below the threshold potential which was determined approximately as −0.3 V vs. SHE even for the irradiated condition at temperatures up to 553 K.