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:
refer to the latest revision of 10 CFR 50.55a and RG 1.147 to identify the provisions of ASME BPV Code and Code Cases on ISI that the NRC has approved. This guide’s principal focus is on the use of PRA findings and risk insights for decisions on changes proposed to plant’s ISI programs for piping. Such changes include (but are not limited to) license amendments under 10 CFR 50.90, requests for the use of alternatives under 10 CFR 50.55a, and exemptions under 10 CFR 50.12, “Specific exemptions.” This guide describes methods acceptable to the NRC staff for integrating insights from PRA techniques with deterministic engineering analyses into ISI programs for piping. The current ISI requirements for piping components appear in 10 CFR 50.55a and the general design criteria (GDC) listed in Appendix A, “General Design Criteria for Nuclear Power Plants,” to 10 CFR Part 50. The NRC incorporated by reference ASME BPV Code, Section XI, in 10 CFR 50.55a, which addresses the codes and standards for design, fabrication, testing, and inspection of piping systems. The objective of the ISI program is to identify service-induced degradation that might lead to pipe leaks and ruptures, thereby meeting, in part, the requirements set in the GDC and 10 CFR 50.55a. ISI programs are intended to address all piping locations that are subject to degradation. Incorporating risk insights into the programs can focus inspections on the more important locations and reduce personnel exposure, while at the same time maintaining or improving public health and safety. The justification for any reduction in the number of inspections should confirm that such a reduction would not result in an increase in leakage frequency or a degradation of defense in depth. When categorizing piping segments in terms of their contribution to risk, it is the responsibility of a licensee to ensure that the categorization of piping segments and the resulting inspection programs are consistent with the key