Electrochemical analysis of CANDU feeder piping characterized by high temperature rotating cylinder electrode

High-temperature Rotating Cylinder Electrode (HTRCE) and water chemistry control system was developed for velocity-sensitive testing at high temperature - high pressure water condition. Potentiodynamic test was performed to Electrochemical analysis on FAC behavior of feeder pipe using the high temperature rotating cylinder electrode and surface analysis of oxide film and ex-situ impedance test was performed to evaluation of oxide property change by FAC phenomenon. ECP has changed with DO concentration, rotating velocity, and temperature and ECP curve with DO concentration shows the sigmoidal shape by variation of the diffusion limiting current for oxygen. Effect of rotating velocity on ECP is diminished over certain DO concentration at certain condition. Subtle increase of flow velocity has no effect on corrosion reaction. However the loss of oxide film is caused by increase of solubility of oxide. Thereby, the electrical resistance of oxide film is reduced by flow of fluid, which results in the reduction of protective role of the oxide film