Document: NRC Regulatory Guide
Document ID: 8e45dce1-e1e7-4415-b1dd-7e2a610e545b
Document Type: regulatory_guide
Title: Fire Protection for Nuclear Power Plants (Rev. 4)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2023/ML20231A835.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.189
CFR Part: 
CFR Title: 

Content:
for pressurized-water reactors (PWRs). Temporary core uncovery in BWRs when depressurizing and using low-pressure systems for post-fire safe shutdown may be acceptable for plants licensed under 10 CFR Part 50. c. The reactor heat removal function should be capable of achieving and maintaining decay heat removal. d. The process monitoring function should be capable of providing direct readings of the process variables necessary to perform and control the above functions. e. The supporting functions should be capable of providing the process cooling, lubrication, and other activities necessary to permit the operation of the equipment used for safe-shutdown functions. GL 81-12 describes the systems and instrumentation that are generally necessary for achieving post-fire safe shutdown for existing PWRs and BWRs. The plant licensing basis includes the systems and instrumentation required for specific plants, and the plant technical specifications address the operating parameters that determine post-fire safe shutdown. DG-1359, Page 76 GDC 3 of Appendix A to 10 CFR Part 50 requires that the FPP protect SSCs important to safety from the effects of fire. However, the post-fire loss of function of systems used to mitigate the consequences of design-basis accidents does not per se affect public safety. The FPP must protect all equipment important to safety; however, the need to limit fire damage to systems required to achieve and maintain post-fire safe-shutdown conditions is greater than the need to limit fire damage to those systems required to mitigate the consequences of design-basis accidents. 5.2 Cold Shutdown and Allowable Repairs For normal safe shutdown, a single fire may damage redundant systems necessary to achieve cold shutdown. As described in the plant-specific licensing basis (i.e., 10 CFR Part 50, Appendix R, Section III.G.1.b, or applicable BTP), fire damage must be limited so that at least one success path can be repaired or made operable within 72 hours