Document: NRC Regulatory Guide
Document ID: 6f84e3bf-9ff3-49fb-a16a-0de3b89e6bc6
Document Type: regulatory_guide
Title: An Approach for Plant-Specific Risk-Informed Decisionmaking for Inservice Inspection of Piping (Rev. 2)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2103/ML21036A105.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.178
CFR Part: 
CFR Title: 

Content:
acceptability of PRA results for risk-informed license amendment requests. This guide supplements the guidance provided in RG 1.174. Specifically, this guide addresses the guidance for developing the RI-ISI programs for piping, with its companion SRP Section 3.9.8. In comparison, RG 1.175, “Plant-Specific, Risk-Informed Decisionmaking: Inservice Testing” (Ref. 11), and RG 1.177, “Plant-Specific, Risk- Informed Decisionmaking: Technical Specifications” (Ref. 12), provide the guidelines for developing risk-informed inservice testing and risk-informed technical specifications, respectively. In September 1998, the Commission published a version of this guide for trial use. As stated therein, that RG did not establish any final staff positions for purposes of 10 CFR 50.109, “Backfitting.” Any changes to the RG before staff adoption in final form would not be considered backfits. This was intended to ensure that the lessons learned during the trial use period could be addressed, enhancing stability in the review, approval, and implementation of proposed RI-ISI programs. Subsequently, the NRC staff approved two methods for developing and implementing RI-ISI programs. The Electric Power Research Institute (EPRI) developed one methodology (EPRI TR-112657, “Revise Risk-Informed Inservice Inspection Evaluation Procedure,” issued December 1999 (Ref. 13)). RG 1.178, Page 5 The Westinghouse Owners Group (WOG) developed the other methodology (WCAP-14572, “Westinghouse Owners Group Application of Risk Informed Methods to Piping Inservice Topical Report,” issued February 1999 (Ref. 14)). The NRC used the trial RG 1.178 to support the review and approval of the two industry-developed methodologies. Based on the experience during the review and approval of the industry methodologies and of numerous plant-specific relief requests for inservice inspection (ISI) programs, the NRC staff issued Revision 1 of this RG in 2003. In addition, the NRC staff has periodically