Document: NRC Regulatory Guide
Document ID: 7d480029-59df-44fe-9db8-c1c86566dac9
Document Type: regulatory_guide
Title: Operation and Maintenance Code Case Acceptability, ASME OM Code (Rev. 5)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2219/ML22196A063.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.192
CFR Part: 
CFR Title: 

Content:
cance using the methodology described in OM Code Case OMN-3, “Requirements for Safety Significance Categorization of Components Using Risk Insights for Inservice Testing of LWR Power Plants,” with the conditions discussed in this RG, or using other MOV risk ranking methodologies accepted by the NRC on a plant-specific or industrywide basis with the conditions in the applicable safety evaluations. DG-1407, Page 10 Code Case Number Table 2 Conditionally Acceptable OM Code Cases Title/Condition Note 1: As indicated at 64 FR 51370–51386, applicants and licensees are cautioned that, when implementing OMN-1, the benefits of performing a particular test should be balanced against the potential adverse effects placed on the valves or systems caused by this testing. Note 2: These conditions are identical to those imposed on OMN-1, Revision 1, in previous revisions to RG 1.192. OMN-3 (2022 Edition) Requirements for Safety Significance Categorization of Components Using Risk Insights for Inservice Testing of LWR Power Plants (1) In addition to those components identified in the ASME IST Program Plan, implementation of Section 1, “Applicability,” of the OM Code Case must include within the scope of an applicant’s or licensee’s risk-informed IST program, non-OM Code Case components categorized as high safety-significant components (HSSCs) that might not currently be included in the IST Program Plan. (2) The decision criteria discussed in Section 4.4.1, “Decision Criteria,” of the OM Code Case for evaluating the acceptability of aggregate risk effects (i.e., for CDF and large early release frequency) must be consistent with the guidance provided in RG 1.174, “An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis” (Ref. 7). (3) Section 4.4.4, “Defense in Depth,” of the OM Code Case must be consistent with the guidance contained in Sections 2.2.1, “Defense-in-Depth Evaluation,”