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:
es additional guidance. DG-1359, Page 101 Risks to equipment important to safety from hydrogen supply systems can be minimized by designing hydrogen lines in plant areas important to safety to seismic Category I requirements, sleeving the piping such that the pipe is directly vented to the outside. Risks can also be minimized through the use of restricting orifices or excess flow valves to limit the maximum flow rate from the storage facility to the areas of concern so that, in case of a line break, the hydrogen concentration in the affected areas will not exceed 2 percent. This approach includes preoperational testing and subsequent retesting of excess flow valves and measures to prevent buildup of unacceptable amounts of trapped hydrogen and inadvertent operation with the safety features bypassed. A somewhat less cost-effective alternative involves use of a normally isolated supply with intermittent manual makeup. EPRI NP-5283-SR-A, “Guidelines for Permanent BWR Hydrogen Water Chemistry Installations,” issued in 1987 (Ref. 119), provides additional guidelines and criteria for the design, installation, and operation of flammable cryogenic and compressed gas systems. 7.6 Nearby Facilities The FPP should address plant support facilities (e.g., offices, maintenance shops, warehouses, temporary structures, equipment storage yards), collocated power generating units (e.g., nuclear, coal, natural gas), and nearby industrial facilities (e.g., chemical plants, refineries, manufacturing facilities) to the extent that fires and or explosions in these facilities may affect equipment important to safety. Fire protection systems and features should be adequate to protect against potential exposure fires and explosions from nearby facilities. 8. Fire Protection for New Reactors 8.1 General Many of the current fire protection requirements and guidelines for operating reactors were issued after Commission approval of construction permits or operating licenses. The imposition