Ongoing Research of Water Chemistry Effect on SCC Properties of Candidate Materials for SCWR

One key issue during development of Super Critical Water Cooled Reactor (SCWR) is selection of water chemistry operating and control methods for core coolant. Under strong corrosive effect of supercritical water (SCW), the stress corrosion cracking (SCC) sensitivity of materials increases. Most of materials reliably used in PWR or BWR may not be competent for SCWR. Modified austenitic steel and nickel base alloy are hopeful due to low general corrosion rate but failures happen caused by SCC when meet incompatible chemistry environment. The possible options of water chemistry specifications for SCWR should be qualified carefully on SCC effect. This paper introduces research status of SCW chemistry by Nuclear Power Institute of China (NPIC). The SCC behaviors in oxidation and reduction SCW are under study and the testing data will be collected to screen out water chemistry operating strategy for million kilowatts SCWR (CSR1000) under development in China.