Technical Basis for Code Case N-809 on Reference Fatigue Crack Growth Curves for Austenitic Stainless Steels in Pressurized Water Reactor Environments

Reference fatigue crack growth curves for austenitic stainless steels in pressurized water reactor environments have been proposed for Section XI flaw evaluation applications. The reference curves are dependent on temperature, loading rate, mean stress, and cyclic stress range, which are all contained in the model. This paper presents the technical basis for the curves, which is based on various research and industry sources. The reference curves for unirradiated material are implemented through Code Case N-809. Applications for N-809 include analytical evaluations for flaw growth to Appendix C and Appendix L of ASME Section XI where environmental effects are important in establishing the service life and inspection interval for austenitic stainless steel piping and components.