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:
eptance are placed on the temperatures measured by a single thermocouple. If any single thermocouple exceeds 30 percent of the maximum allowable temperature rise (i.e., 139 ºC + 42 ºC = 181 ºC (250 ºF + 75 ºF = 325 ºF), the test exceeds the temperature criteria limit. b. Irrespective of the unexposed side temperature rise during the fire test, if the fire barrier test specimen includes cables or components, a visual inspection is performed. When the temperature criteria are exceeded or damage occurs, component operability or functionality at the temperatures experienced during the fire test should be assessed. Fire endurance tests that are judged acceptable on the basis of a visual inspection of specific components or cables included in the test specimen may not be applied to other components or cables without a specific evaluation. Cables should not show signs of degraded conditions resulting from the thermal effects of the fire exposure. Examples of thermal cable degradation are jacket swelling, splitting, cracking, blistering, melting, or discoloration; shield exposed; conductor insulation exposed, degraded, or discolored; and bare copper conductor exposed. When signs of thermal degradation are present, the fire barrier did not perform its intended fire-resistive function. For barriers that are not capable of performing their intended function, an engineering analysis should be performed to demonstrate that the functionality of thermally degraded cables or components was maintained and that the cables or components would have adequately performed their intended functions during and after a postulated fire exposure. A methodology for demonstrating the functionality of cables during and after a fire test exposure is provided below. The purpose of the functionality tests is to justify observed deviations in fire barrier performance. For fire barrier specimens that are tested without cables, an engineering analysis justifying internal fire barrier temperature