Factors Affecting the Crack Growth Rates of Reactor Pressure Vessel Steels under Simulated Boiling Water Reactor Conditions

Crack growth rate (CGR) measurement is an important tool to understand the behaviors of environmentally assisted cracking (EAC) of various materials used in light water reactor (LWR) environments and to produce quantitative data for structural integrity analyses, as well as for dispositioning existing or postulated defects. In this paper, the results of corrosion fatigue (CF) and stress corrosion cracking (SCC) experiments with two different reactor pressure vessel (RPV) steels at 288°C (˜561 K) under simulated boiling water reactor (BWR) conditions are presented. CGR was found to be dependent upon various mechanical factors such as the stress intensity factor range (ΔK), loading frequency, and hold time (ΔtH) at maximum load. In CF tests, it was observed that whether the loading frequency was high or low, the fatigue crack growth rate (FCGR) increased as ΔK increased under the same water quality and loading conditions. In SCC tests, the longer the ΔtH, the slower the CGR. On the other hand, it w...