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:
comply with the requirements of Class A systems, as defined in NFPA 72, “National Fire Alarm Code” (Ref. 68), and Class I circuits, as defined in NFPA 70, “National Electrical Code” (Ref. 69). DG-1359, Page 45 c. Fire detectors are selected and installed in accordance with NFPA 72. Preoperational and periodic testing of a pulsed-line type of heat detector demonstrates that the frequencies used will not affect the actuation of protective relays in other plant systems. d. Fire detection and alarm systems give audible and visible alarms and annunciation in the control room. Where zoned detection systems are used in a given fire area, local means identify which detector zone has actuated. e. Fire alarms are distinctive and unique to avoid confusion with any other plant system alarms. f. Primary and secondary power supplies are provided for the fire detection system and for electrically operated control valves for automatic suppression systems. Such primary and secondary power supplies should satisfy the provisions of NFPA 72. This can be accomplished by using normal offsite power as the primary supply, with a 4-hour battery supply as a secondary supply, and by providing the capability for manual connection to the Class 1E emergency power bus within 4 hours of loss of offsite power. Such connection should follow the applicable guidance in RG 1.6, “Independence Between Redundant Standby (Onsite) Power Sources and Between Their Distribution Systems” (Ref. 70); RG 1.32, “Criteria for Power Systems for Nuclear Power Plants” (Ref. 71); and RG 1.75, “Physical Independence of Electric Systems” (Ref. 72). g. In areas of high seismic activity, licensees should consider the need to design the fire detection and alarm systems to function following a safe-shutdown earthquake. h. The fire detection and alarm systems should retain their original design capability for (1) natural phenomena of less severity and greater frequency than the most severe natural phenomena