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 integrated decisionmaking process and criteria used for categorizing the safety significance of piping segments, a description of how the integrated RG 1.178, Page 24 decisionmaking was performed, a description and justification of the number of elements to be inspected in a piping segment, the qualifications of the individuals making the decisions, and the guidelines for making those decisions. f. Present the results of the licensee’s ISI-specific analyses used to support the program change with enough detail to be clearly understandable to the reviewers of the program. These results should include the following information: (1) List the piping systems reviewed. (2) List each segment, including the number of welds, weld type, and properties of the welding material and base metal, the failure potential, CDF, conditional CDF, LERF, conditional LERF, conditional core damage probability, conditional large early release probability, importance measure results (e.g., risk achievement worth, Fussel-Vesely) and justification of the associated threshold values, degradation mechanism, and test and inspection intervals used in or in support of the PRA. Results from other methods used to develop the consequences and categorization of each segment (or weld) should be documented with a similar level of detail. (3) Describe the degradation mechanisms for each segment (if segments contain welds exposed to different degradation mechanism, for each weld) used to develop the failure potential of each segment. For the selected limiting locations, provide examples of the failure mode, failure potential, failure mechanism, weld type, weld location, and properties of the welding material and base metal. (4) Provide a detailed description and justification for the number of elements to be inspected. (5) List the equipment assumed to fail as a direct or indirect consequence of each segment’s failure (if segments contain welds with different failure consequences, for each weld). (6)