Document: NUREG-0800
Document ID: 05a851a6-07ff-41b4-8528-a032ba433e04
Document Type: srp
Title: FIRE PROTECTION PROGRAM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0327/ML032740044.pdf
Revision Date: 2023-06
Chapter: 9
Section ID: 9.5.1
CFR Part: 
CFR Title: 

Content:
t meet the requirements of 10 CFR Part 50.48(a) and 10 CFR Part 50, Appendix A, General Design Criterion 3, to provide an enhanced level of fire protection beyond that provided for currently operating reactors, and is reviewed to the applicable guidelines in this BTP. 6. Assumptions of Fire Occurrence Revision 4 - October 2003 12 6.1 Postulated Fire and Fire Damage Fire damage to safe shutdown equipment or fires with the potential to result in release of radioactive materials to the environment are assessed on the basis of a single fire, including an exposure fire. An exposure fire is a fire in a given area that involves either in situ or transient combustibles and has the potential to affect structures, systems, and components important to safety or radioactive materials located in or adjacent to that same area. The effects of such fire (e.g., smoke, heat, or ignition) can adversely affect those structures, systems, and components important to safety. Thus, a fire involving one success path of safe shutdown equipment may constitute an exposure fire for the redundant success path located in the same area, and a fire involving combustibles other than either redundant success path may constitute an exposure fire to both redundant success paths located in the same area. Damage limits for hot shutdown and cold shutdown systems and components are described in the safe shutdown review guidelines in this BTP. Redundant systems necessary for mitigation of consequences following design basis accidents, but not required for safe shutdown may be damaged by a single exposure fire. The most stringent fire damage limit should apply for those systems that fall into more than one category. The fire event for considering the need for alternative or dedicated shutdown is a postulated fire in a specific fire area containing redundant safe shutdown cables/equipment where it has been determined that fire protection systems and features cannot be provided to ensure that safe shutdown