Adaptation of Linear Polarization Techniques for In-Situ Corrosion Measurements in Water Cooled Nuclear Reactor Environments

Abstract

Abstract Application of electrochemical polarization techniques to study corrosion of steels in aqueous environments at 289 C (554 F) and 1000 psi is described. A galvanostatic polarization circuit is discussed which permits determination of polarization parameters in-situ which are free of error due to resistance polarization in high purity water. Extended corrosion tests on plain carbon steel and Type 304 steel over 500 hours have shown that 99.6 percent correspondence can be achieved between electrochemical corrosion data and conventional weight-change techniques. In de-oxygenated conditions, the steady-state corrosion rates of plain carbon steel and Type 304 stainless steel are 0.0015 and 0.0011 mg/cm2hr, respectively in water at 289 C. Cathodic and anodic Tafel constants for these steels under the above conditions have been determined and are shown to be independent of exposure time and corrosion rate.