Risk-informed snubber inservice testing guidelines: Pilot project studies. Final report
Most plant snubber examination and test program requirements are based on the NRC Standard Technical Specifications, or the ASME OM Code Subsection ISTD. Recently the NRC has allowed these snubber requirements to be removed from the plant Technical Specifications to a licensee controlled document, which can be modified via the 10CFR50.59 process. This EPRI research project is providing the technical basis for a risk-informed change to the snubber requirements. This project builds on previous EPRI and ASME work to develop this risk-informed (RI) methodology for inservice testing IST of safety-related snubbers. The NRC has already embarked on RI-IST, as well as other risk-informed initiatives. This methodology consists of applying the new standard risk-informed IST process which consists of: risk ranking the IST components utilizing plant specific PRA; blending the probabilistic and deterministic information; making a safety categorization decision for each IST component as either HSSC or LSSC; and identifying different testing strategies for HSSC versus LSSC components. Since snubbers are not modeled in the PRA, system functional risk was deemed to be an adequate surrogate measure of snubber risk. The methodology developed in this research study was applied to seven pilot plants (eleven units) to determine the impact on plant safety, outage costs, and snubber failures. Three of those plants applied the methodology to all safety-related snubbers.
- Research Organization:
- Electric Power Research Inst. (EPRI), Palo Alto, CA (United States); Wesley Corp., Tulsa, OK (United States); Palmer Group International, Hixson, TN (United States)
- Sponsoring Organization:
- Electric Power Research Inst., Palo Alto, CA (United States)
- OSTI ID:
- 354922
- Report Number(s):
- EPRI-TR-110381; TRN: AHC29924%%126
- Resource Relation:
- Other Information: PBD: Mar 1998
- Country of Publication:
- United States
- Language:
- English
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