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:
ically inspects the production of listed equipment or materials and states that certain specific equipment or materials meet nationally recognized standards and have been tested and found suitable for use in a specified manner. mitigate: Perform an action that stops the progression of or reduces the severity of an unwanted condition. With respect to nuclear plant fire protection, mitigation generally refers to operator actions inside or outside the main control room to restore the capability to achieve and maintain safe shutdown when a fire has degraded that capability. new reactors: Those reactors that are significantly different in operation from the current generation of LWRs and that provide enhanced margins of safety or use simplified, inherent, or other innovative means to accomplish their safety functions. noncombustible material: (1) Material that, in the form in which it is used and under conditions anticipated, will not ignite, burn, support combustion, or release flammable vapors when subjected to fire or heat, or (2) material having a structural base of noncombustible material, with a surfacing not over 3 mm (1/8 in.) thick that has a flame spread rating no higher than 50 when DG-1359, Page 110 measured in accordance with ASTM E84, “Standard Test Method for Surface Burning Characteristics of Building Materials.” open circuit: A failure condition that results when a circuit (either a cable or individual conductor within a cable) loses electrical continuity. operator action: A normal action taken by an operator inside the main control room to achieve and maintain a post-fire safe shutdown, not including repairs. operator manual action: Actions performed by operators to manipulate components and equipment from outside the main control room to achieve and maintain post-fire hot shutdown, not including “repairs.” Operator manual actions include an integrated set of actions needed to ensure that hot shutdown can be accomplished for a fire in a specific