Document: NRC Regulatory Guide
Document ID: 666e1303-0170-4974-a7d6-af27eb586524
Document Type: regulatory_guide
Title: Risk-Informed, Performance-Based Fire Protection for Existing Light-Water Nuclear Power Plants (Rev. 2)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2104/ML21048A448.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.205
CFR Part: 
CFR Title: 

Content:
, compared to the NFPA 805 deterministic criteria, is less than the acceptance guidelines in RG 1.174. In this case, the NRC will normally approve risk increases in that fire area resulting from other alternatives to deterministic compliance, not previously approved, provided that the total risk increase for that fire area (i.e., from previously approved recovery actions and the other alternatives) meets the acceptance guidelines in RG 1.174. If this total risk increase exceeds the acceptance guidelines in RG 1.174, the NRC staff will not normally approve the proposed alternatives. If there is no net risk increase in a fire area (block [3]), or if the total additional risk from alternatives to deterministic criteria, both previously approved and not previously approved, is within the acceptance guidelines in RG 1.174 (block [4]), then the NRC staff will normally find that the additional risk associated with that fire area is acceptable for making the transition to NFPA 805 (block [6]). Figure 1. Framework for Fire Risk Evaluations during Transition When Crediting Previously Approved Recovery Actions (RAs) [Δrisk = change in risk; PB = performance based] RG 1.205, Revision 2, Page 12 2.2.4.2 Total Plant Delta Risk of Implementing NFPA 805 The total increase or decrease in risk associated with the implementation of NFPA 805 for the overall plant should be calculated by summing the risk increases and decreases for each fire area (including any risk increases resulting from previously approved recovery actions). The total risk increase should be consistent with the acceptance guidelines in RG 1.174. Note that the acceptance guidelines of RG 1.174 may require the total CDF, LERF, or both to evaluate changes for which the risk impact exceeds specific guidelines. If the additional risk associated with previously approved recovery actions is greater than the acceptance guidelines in RG 1.174, then the net change in total plant risk incurred by any proposed alternatives to