Application of Common Basis Stress Evaluation Methodology for Environmentally Assisted Fatigue for a Pressurized Water Reactor

United States (US) Nuclear Regulatory Commission (NRC) report NUREG-1801, the Generic Aging Lessons Learned (GALL) Report [1], identifies acceptable aging management programs, including programs for fatigue and cyclic operation, and is used by the NRC to evaluate license renewal applications. This includes fatigue usage analyses that account for reduced fatigue life for components in a reactor water environment. Originally, it was considered acceptable for the purpose of license renewal to evaluate only the sample locations identified in NUREG/CR-6260. Recently, however, the NRC staff has been requesting license renewal applicants to demonstrate that the locations identified in NUREG/CR-6260 are the limiting locations for environmentally assisted fatigue (EAF), such that EAF evaluations are limited to the NUREG/CR-6260 locations. Any locations not bounded by the NUREG/CR-6260 locations would then be specifically addressed. A methodology has been developed for EPRI, called common basis stress evaluation (CBSE), to perform simplified stress and fatigue usage analyses in a consistent manner such that many locations can be compared for fatigue usage with and without the use of EAF, even if prior analyses of these locations were not consistent in level of detail, and even if some locations have never been evaluated for fatigue usage. This paper presents the first application of this methodology.Copyright © 2013 by ASME