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:
e 7 • developing an inspection program that monitors the performance of the piping elements for consistency with the conclusions from the risk assessment This guide only addresses changes to the ISI programs for inspection of piping. To adequately reflect the risk implications of piping failure, both partial- and full-scope RI-ISI programs are acceptable to the NRC staff. A licensee may elect to limit its RI-ISI program to a subset of piping classes, such as ASME Class 1 piping only. Partial-scope applications should include the full population of piping within the selected subset of piping, such as ASME Class or plant systems. A full-scope RI-ISI includes the following: • all Class 1, 2, and 3 piping1 within the current ASME BPV Code, Section XI, programs • all piping whose failure would compromise the following: o safety-related structures, systems, or components (SSCs) that are relied upon to remain functional during and following design-basis events to ensure the integrity of the reactor coolant pressure boundary, the capability to shut down the reactor and maintain it in a safe-shutdown condition, or the capability to prevent or mitigate the consequences of accidents that could result in potential offsite exposure comparable to the guidelines in 10 CFR Part 100, “Reactor Site Criteria” o nonsafety-related SSCs with the following characteristics:  relied upon to mitigate accidents or transients or are used in plant emergency operating procedures, or  whose failure could prevent safety-related SSCs from fulfilling their safety-related function, or  whose failure could cause a reactor scram or actuation of a safety-related system For both the partial- and full-scope evaluations, the licensee is to ensure compliance with the acceptance guidelines and key principles of RG 1.174. In the evaluations for developing RI-ISI programs, the locations of concern include all weld and base metal locations at which degradation may occur, although pipe welds