High temperature electrochemical reaction parameters affecting elecrochemical corrosion potential of type 316L stainless steel

High temperature electrochemical reaction parameters for type 316 L stainless steel (316 L SS) have been determined based on data measured in pure water at high temperatures to realize an analytical model that can predict electrochemical corrosion potential (ECP) of 316 L SS without using any adjustment parameters based on ECP data. Behaviors of measured polarization curves for 316 L SS could be explained well with the determined parameters. Calculated ECPs of 316 L SS agreed with measured values in the case that it was acceptable for the model to have an error range of ±0.1 V in a wide oxygen concentration range. However, the error was relatively larger in the range from 10 to 100 ppb oxygen concentration because of the shape of the anodic polarization curve of 316 L SS; in other words, ECP could not be uniquely determined in such an oxygen concentration range. It is expected that the ECP model with the determined electrochemical parameters will have greater validity for, and better interpretability of, the ECPs of SS determined in a boiling water reactor environment.