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:
d: a. Provide appropriate measures to prevent propagation of the fire. b. Provide electrical protection (e.g., breakers, fuses, or similar devices). 5.4.5 Control Room Fires The control room fire area contains the controls and instruments for redundant shutdown systems in proximity. (Separation is usually a few inches.) Alternative or dedicated shutdown capability for the control room and its required circuits should be independent of the cables, systems, and components in the control room fire area. The damage to systems in the control room for a fire that causes evacuation of the control room cannot be predicted. The licensee should conduct a bounding analysis to ensure that safe conditions can be maintained from outside the control room. This analysis is dependent on the specific design. The following assumptions usually apply: DG-1359, Page 89 a. The reactor is tripped in the control room. b. Offsite power is lost, as well as automatic starting of the onsite AC generators and the automatic function of valves and pumps with control circuits that could be affected by a control room fire. The analysis should demonstrate the capability to manually achieve safe-shutdown conditions from outside the control room by restoring AC power to designated pumps, ensuring that valve lineups are correct, and assuming that any malfunctions of valves that permit the loss of reactor coolant can be corrected before unrestorable conditions occur. The only operator action in the control room before evacuation for which credit is usually given is reactor trip. For any additional control room actions deemed necessary before evacuation, a licensee should be able to demonstrate that such actions can be performed. Additionally, the licensee should ensure that such actions cannot be negated by subsequent spurious actuation signals resulting from the postulated fire. The design basis for the control room fire should consider one spurious actuation or signal to occur before control of the