Investigation on the Effects of Denting Occurring in Alloy 600 SG tubing on Environmental Parameters in Operating Nuclear Power Plants

Steam generator in operating nuclear power plants(NPPs) is one of main facilities, which is a pressure boundary between the primary and secondary systems in NPPs and generating steam to operate a turbine of electric generator to make electricity. Therefore, if the steam generator is failed to operate, the operating nuclear power plants should be tripped unexpectedly. This results in a tremendous loss economically and a safety issue which is very important to public opinions. One of main issues for its safe operation is steam generator tube failure by denting corrosion which causes primary and secondary stress corrosion cracking inducing the leakage of the primary cooling water into the secondary system during operation. This leakage can contaminate the secondary system with radioactive materials causing safety problems in operating nuclear power plants (NNPs). In order to mitigate and/or prevent denting corrosion occurring in operating NNPs, the effects of the environmental parameters on denting corrosion should be evaluated in their operating conditions. In this study, in order to examine the effects of parameters on denting corrosion, denting corrosion experiments were performed in various test conditions