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:
., updated final safety analysis report, supporting analyses) are met, or proposed revisions provide sufficient margins to account for analysis and data uncertainty. 2.1.4 Piping Segments A systematic approach should be applied when analyzing piping systems. One acceptable approach is to divide or separate a piping system into segments; different criteria or definitions can be applied to each piping segment. Another acceptable method is to identify segments of piping within the piping systems that have the same consequences of failure. Other methods could subdivide a segment that exhibits a given consequence into segments with similar degradation mechanisms or similar failure potential. The definition of a segment could encompass multiple criteria, as long as a sound engineering RG 1.178, Page 14 and accounting record is maintained and can be applied to an engineering analysis in a consistent and sound process. Consequences of failure may be defined in terms of an initiating event, loss of a particular train, loss of a system, or combinations thereof. The location of the piping in the plant, and whether inside or outside the containment or compartment, should be considered when defining piping segments. The definition of a piping segment can vary with the methodology. Defining piping segments can be an iterative process. In general, an analyst may need to modify the description of the piping segments before they are finalized. This guide does not impose any specific definition of a piping segment, but the analysis and the definition of a segment must be consistent and technically sound. 2.1.5 Assess Piping Failure Potential The engineering analysis includes evaluating the failure potential of a piping segment. Determining the failure potential of piping segments, either with a quantitative estimate or by categorization into groups, should be based on an understanding of such parameters as degradation mechanisms, operational characteristics, potential dynamic loads,