Chemical Thermodynamics Consideration on Corrosion Products in Supercritical-Water-Cooled Reactor Coolant

In order to elucidate the dissolution/deposition behavior of corrosion products in supercritical-water-cooled reactor (SCWR) coolant, chemical thermodynamics calculation was carried out, taking into account the electrochemical properties of supercritical water. The review of thermodynamics models revealed the applicability of the modified HKF model for ionic species in the supercritical region. Using the calculation results, potential-pH diagrams were drawn for metal/water systems, which exhibited the effect of temperature and pressure on the stability of oxide in the SCWR core region.