High temperature electrochemical reaction parameters affecting electrochemical corrosion potential of Ni-base Alloy 182

High-temperature electrochemical reaction parameters for nickel-base Alloy 182 weld metal (Alloy 182) 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 Alloy 182 without using any adjustment parameters based on ECP data. Behaviors of measured polarization curves for Alloy 182 could be explained well with the determined parameters. Calculated ECPs of Alloy 182 agreed with the measured values in the cases that it was acceptable for the model to have an error range of ±0.1 V in a range from the deaerated condition to 10,000 ppb (=μg kg^-1) oxygen concentration. It is expected that the ECP model with the determined electrochemical reaction parameters will have greater validity for, and better interpretability of, the ECPs of Alloy 182 determined in a boiling water reactor environment than previous models. (author)