Probing Corrosion Activity in High Subcritical and Supercritical Water Through Electrochemical Noise Analysis

A chemistry and corrosion monitoring system was devised to monitor chemistry parameters and corrosion activity in the heat transport circuits of thermal power plants. The system included an electrochemical noise analyzer (ENA) to probe the corrosion activities of metals and alloys in contact with the heat transport fluid. Electrochemical noise was measured as a function of oxygen concentration ([O2]), flow rate, temperature, and pressure in simulated heat transport circuit fluids at temperatures up to 550°C and at pressures as high as 276 bar (4,000 psi, 27.6 MPa). Electrochemical noise from corroding carbon steel could be measured in high subcritical and supercritical water, and the magnitude of the noise responded in a sensible manner to changes in the chemical and physical properties of the fluid.