PWSCC in Alloy 600 and IG Crack Growth Rates in PWR environments

Austenitic nickel-based Alloy 600 has been used as structural materials in nuclear power plants due to its good mechanical properties and high corrosion resistance. However, PWSCC(Primary Water Stress Corrosion Cracking) occurs in the primary-circuit structural materials fabricated from Alloy 600, such as reactor vessel head nozzles including CRDM(Control Rod Drive Mechanism) and in-core instrument nozzles. Depending on test conditions, microstructure of components and so on, crack growth rate in stress corrosion cracking is significantly different. Many researches on stress corrosion cracking in primary water reactor environments have been carried out to demonstrate effects of various factors on crack growth rate. It is the purpose of this study to investigate effects of stress intensity factor (K) value on crack growth rate of a wrought alloy 600 in primary water reactor environments