Corrosion of Structural Materials and Electrochemistry in High-Temperature Water - Relationships among Water Chemistry, Corrosion, Oxide Film and Electrochemical Corrosion Potential

摘要

In order to establish reliable nuclear power plant operation, each plant requires its own unique optimal water chemistry control based on careful consideration of its system, materials and operational history. Electrochemistry is one of the key issues that determine corrosion-related problems, e.g., flow-accelerated corrosion (FAC), intergranular stress corrosion cracking and primary water stress corrosion cracking. Most phenomena of corrosion can be understood based on an electrochemical index, e.g., electrochemical corrosion potential (ECP), conductivities and pH. Based on the relationships among ECP, metal surface conditions, exposure time and other environmental conditions, a model to evaluate the ECP and corrosion rate of steel was developed by coupling an electrochemical model and an oxide layer growth model.