Document: NRC Regulatory Guide
Document ID: 80776ca5-a83d-4667-9a94-0bffa1befa91
Document Type: regulatory_guide
Title: Fire Protection Guidelines for Nuclear Power Plants (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1221/ML12216A013.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.120
CFR Part: 
CFR Title: 

Content:
are used, two 100% (minimum of 300,000 gallons each) system capacity tanks should be installed. They should be so interconnected that pumps can take suction from either or both. However, a leak in one tank or its piping should be isolable so that it will not cause both tanks to drain. Water supply capacity should be capable of refilling either tank in eight hours or less. Common tanks are permitted for fire and sanitary or service water storage. When this is done, however, minimum fire water storage requirements should be dedicated by passive means, for example, use of a vertical standpipe for other water services. (5) The fire water supply should be calculated on the basis of the largest expected flow rate for a period of two hours, but not less than 300,000 gallons. This flow rate should be based (conservatively) on 750 gpm for manual hose streams plus the largest design demand of any sprinkler or deluge system as determined in accordance with NFPA 13 or NFPA 15. The fire water supply should be capable of delivering this design demand over the longest route of the water supply system. (6) Freshwater lakes or ponds of sufficient size may qualify as sole source of water for fire protection but require at least two intakes to the pump supply. One hundred percent capacity should be available following the loss of any one intake. When a common water supply is permitted for fire protection and the ultimate heat sink, the following conditions should also be satisfied: (a) The additional fire protection water requirements are designed into the total storage capacity and (b) Failure of the fire protection system should not degrade the function of the ultimate heat sink. (7) Outside manual hose installation should be sufficient to provide an effective hose stream to any onsite location where fixed or transient combustibles could jeopardize safety- related equipment. To accomplish this, hydrants should be Installed approximately every 250 feet on the yard main system. A hose