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:
only to support a reduction in the number of inspections but also to identify areas where increased resources should be allocated to enhance safety. Therefore, an acceptable RI-ISI process should not focus exclusively on areas in which reduced inspection could be justified. This section addresses ISI-specific considerations in the PRA to support relaxation of inspections, enhancement of inspections, and validation of component operability. The PRA can be used to categorize the piping segments into safety-significant and low-safety-significant classifications (or more classifications, if a finer graded approach is desired) and to confirm that the change in risk caused by the change in the ISI program is in accordance with the guidance of RG 1.174. RG 1.174 contains much of the general guidance that is applicable to this topic. A PRA used in a risk-informed regulation should be performed correctly, in a manner consistent with accepted practices. RG 1.200 describes one acceptable approach for determining whether the acceptability of the PRA, in total or the parts that support an application, is sufficient to provide confidence in the results, such that the PRA can be used in regulatory decisionmaking for LWRs. Section C.2.3.1 in RG 1.174 discusses, in general terms, issues related to the scope, level of detail, conformance with the technical elements needed in a PRA as described in RG 1.200, and plant representation of a PRA that is used for risk-informed applications. These aspects of the PRA should be commensurate with its intended use and the role the PRA results play in the integrated decision process. Sections C.2.3.2, C.2.3.3, and C.2.3.4 in RG 1.174 give more specific considerations and address the use of PRA in categorizing and assessing the impact on risk metrics, respectively. NRC safety evaluation dated January 18, 2012, “Final Safety Evaluation of Electric Power Research Institute Topical Report, 1021467, Revision 0, Nondestructive Evaluation: