Document: NRC Regulatory Guide
Document ID: 47b09be1-4bf8-45f9-a099-7fed871c09bd
Document Type: regulatory_guide
Title: Plant-Specific, Risk-Informed Decisionmaking: Inservice Testing (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2114/ML21140A055.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.175
CFR Part: 
CFR Title: 

Content:
changes to the IST program and to evaluate the impact of the changes on the overall plant risk. Areas that are to be evaluated include the expected effect of the proposed RI-IST program on the design basis and severe accidents, defense-in-depth attributes, and safety margins. This evaluation considers the results of deterministic engineering and PRA methods together in an integrated decision process that will be carried over into the implementation phase (see Element 3). PRA results should be used to provide information for categorizing components into groupings of low safety-significant components (LSSCs) and high safety-significant components (HSSCs). Components in the LSSC group would then be candidates for less rigorous testing when compared with those in the HSSC group. When the revised IST plan has been developed, the plant-specific PRA should be used to evaluate the effect of the planned program changes on the overall plant risk, as measured by CDF and containment LERF. During the integration of all the available information, many issues will need to be resolved using judgment, often involving a combination of different engineering skills. Industry documents typically refer to this activity as being performed by an “expert panel.” As discussed at the end of this section and in the appendix to this RG, this important process is the licensee’s responsibility and may be accomplished by means other than a formal panel. In any case, the key principles discussed in this guide should be addressed and shown to be satisfied regardless of the approach used for RI-IST program decisionmaking. RG 1.175, Page 7 Regulatory Position C.2 contains additional application-specific details concerning RI-IST programs and Element 2. Element 3: Define Implementation and Monitoring Program. The purpose of this element is to develop the implementation plan for the IST program. This involves determining both the methods to be used and the frequency of testing. The frequency and