Document: NRC Regulatory Guide
Document ID: 30e6fa68-c7c1-4266-ba45-e06d1bbc07a0
Document Type: regulatory_guide
Title: Criteria for Accident Monitoring Instrumentation for Nuclear Power Plants (Rev. 5)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1708/ML17083A134.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.97
CFR Part: 
CFR Title: 

Content:
97 may be used to select only Type F variables and determine their design, performance, qualification, and display criteria. For these modifications, the licensee should perform an analysis addressing only the severe accident variables in accordance with the selection criteria in this revision. When a licensee elects to adopt this revision for only Type F variables and remains committed to an earlier version of RG 1.97 for variables of Type A, B, C, D, and E, the licensee should document how it applied each revision of RG 1.97. 3. The scope of variables analyzed as Type A should include variables that are associated with contingency actions. Specifically, the application of the term “contingency actions” should be modified by deleting the words “do not” from the next-to-last sentence in Clause 4.1, “Type A variables.” The revised sentence is clarified as follows: Type A variables include those variables that are associated with contingency actions that are within the plant licensing basis and may be identified in written procedures. IEEE Std. 497-2016 defines “contingency actions” as “alternative actions taken to address unexpected responses of the plant or conditions beyond its licensing basis (e.g., actions taken for multiple equipment failures).” Clause 4.1 of IEEE 497-2016 uses this term in defining selection criteria for Type A variables. The NRC staff agrees with the criteria in this clause, except for the exclusion of variables that are associated with contingency actions. Nuclear steam supply system vendors have not used this term consistently in emergency procedure guidelines. Therefore, the NRC staff does not endorse the exclusion of variables associated with contingency actions from DG-1335, Page 9 the selection criteria (especially those associated with plant-specific operating procedures or guidelines). Rather, the scope of the analysis for variables of this type should be as inclusive as possible. Thus contingency variables may or