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:
ew information becomes available that could impact the ISI program. For example, if changes to the PRA impact the decisions made for the RI-ISI program, if plant design and operations change such that they impact the RI-ISI program, if inspection results identify unexpected flaws, or if replacement activities impact the failure potential of piping, the effects of the new information should be assessed. The periodic evaluation may result in updates to the RI-ISI program that are more restrictive than required by Section XI. As plant design feature changes are implemented, changes to the input associated with the RI-ISI program segment definition and element selections should be reviewed and modified as needed. Changes to piping performance or the plant procedures that can affect system operating parameters, piping inspections, component and valve lineups, equipment operating modes, or the ability of the plant personnel to perform actions associated with accident mitigation should be reviewed in any RI-ISI program update. Leakage and flaws identified during scheduled inspections should be evaluated as part of the RI-ISI update. Piping segments categorized as safety significant that are not in the licensee’s current ISI program should (wherever appropriate and practical) be inspected in accordance with applicable ASME Code Cases (or revised ASME BPV Code), including compliance with all administrative requirements. Where ASME BPV Code, Section XI, inspection is not practical or appropriate, or it does not conform to the key principles identified in this document, the licensee should develop alternative inspection intervals, scope, and methods to ensure piping integrity and to detect piping degradation. The licensee should provide a summary of the piping segments and their proposed inspection intervals and scope to the NRC before implementation of the RI-ISI program at the plant. For piping segments categorized as safety significant that were the subject of a previous