Analysis of Empirical Probability of Detection Data for Dissimilar Metal Welds
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
The U.S. Nuclear Regulatory Commission’s (NRC) Standard Review Plan (SRP) 3.6.3 describes leak-before- break (LBB) assessment procedures that can be used to assess compliance with the 10 CFR 50 Appendix A, General Design Criteria (GDC)-4 requirement that primary system pressure piping exhibit an extremely low probability of rupture. SRP 3.6.3 does not allow for assessment of piping systems with active degradation mechanisms, such as primary water stress corrosion cracking (PWSCC), which is currently occurring in systems that have been granted LBB approvals. To address those piping systems approved for LBB that are experiencing PWSCC, the NRC Office of Nuclear Regulatory Research (RES) working cooperatively with the Electric Power Research Institute (EPRI) conducted a multi-year project to develop a probabilistic fracture mechanics code called eXtremely Low Probability of Rupture (xLPR) that can be used to assess compliance with the regulations. xLPR is a probabilistic computational tool capable of evaluating degradation in reactor coolant piping welds leading to rupture with extremely low probabilities of occurrence. This tool models the effects of active degradation mechanisms and the inspection and mitigation activities that are being undertaken to manage PWSCC degradation. Crack initiation and growth due to fatigue and primary water stress corrosion, along with mitigation methods (mechanical mitigation as well as chemical mitigation) and the effects of in-service inspection (ISI) and leak detection can be analyzed using this tool.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE; US Nuclear Regulatory Commission (NRC)
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1648404
- Report Number(s):
- PNNL--28090
- Country of Publication:
- United States
- Language:
- English
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