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:
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 capability will be preserved. 6.2 Conditions of Fire Occurrence It is assumed that a fire may occur at any time, but is not postulated to occur simultaneously with plant accidents or with severe natural phenomena such as floods or high winds. However, severe natural phenomena, such as earthquakes, may initiate a fire event and should be considered in evaluating the design capability of fire protection systems and features. On multiple reactor sites, unrelated fires in two or more units need not be postulated to occur simultaneously. Fires involving facilities shared between units and fires caused by natural or man-made events that have a reasonable probability of occurring and affecting more than one reactor unit should be considered. 6.3 Loss of Offsite Power/Station Blackout In evaluating the capability to accomplish post-fire safe shutdown, offsite power may or may not be available and consideration should be given to both cases. However, loss of offsite power need not be considered for a fire in non-alternative or dedicated shutdown areas if it can be shown that offsite power cannot be lost due to a fire in that area. As described in Position 5.6.1 of Regulatory Guide 1.189, alternative shutdown capability should accommodate post-fire conditions where offsite power is available and where offsite power is not available for 72 hours. In evaluating safe shutdown circuits, including associated circuits, the availability of uninterrupted power (i.e., offsite power available) may impact the Revision 4 - October 2003 13 ability to control the safe shutdown of the plant by increasing the potential for associated circuit interactions resulting from fire damage to energized power and control circuits. Reliance on station blackout to accomplish safe shutdown objectives is