The electrical resistivity of the oxide film formed on 304 stainless steel (SS) in 288°C water was evaluated by an in-situ AC impedance measurement. The higher electrochemical corrosion potential (ECP) was measured in the presence of hydrogen peroxide (H2O2) than oxygen (O2), and the polarization resistance decreased with increases in ECP and H2O2 concentration. The impedance data suggested that a less resistive oxide was produced when H2O2 was present in water.
Key words: impedance, polarization resistance, high temperature water, BWR, stainless steel.