Development of a stress corrosion cracking test methodology using tube-shaped specimens

Stress corrosion cracking (SCC) is one of the greatest concerns in nuclear aging and degradation, and studies on the measurement of stress corrosion crack growth rates (CGR) and the effects of environmental, material, and mechanical parameters on the CGR have been performed using mainly fracture mechanics specimens. However, the stress states for the fracture mechanics specimens are different from that of real field components and there is concern about the applicability of the data obtained from fracture mechanics specimens to the evaluation of SCC behaviors in real field components. In this study, in order to obtain SCC for specimens that have a similar shape of real field components under complicated stress states, an SCC test methodology using specimens in the shape of tubes was developed. Its effectiveness was verified by performing an SCC test using a mock-up of a bottom mount instrumentation tube of a pressurized water reactor (PWR) under a simulated PWR primary water environment. Intergranular SCC was created in the mock-up specimen using the developed SCC test methodology and SCC crack growth rate for the mock-up specimen was measured.