Heat Release Rate and Fire Characteristics of Fuels Representative of Typical Transient Fire Events in Nuclear Power Plants (NUREG-2232, EPRI 3002015997)

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Publication Information

Date Published: March 2020

U.S Nuclear Regulatory Commission
Office of Nuclear Regulatory Research (RES)
Washington, DC 20555-0001

Electric Power Research Institute (EPRI)
3420 Hillview Avenue
Palo Alto, CA 94304-1338

U.S. NRC-RES Project Manager
M. Salley

EPRI Project Managers
A. Lindeman

Availability Notice


As part of the initial guidance for performing a fire probabilistic risk assessment (FPRA) contained in NUREG/CR-6850, the appendices in Volume 2 provided guidance on modeling the heat release rate of ignition sources. Follow-on research has improved the realism for the heat release rates used for electrical cabinets (NUREG-2178, Volume 1, and NUREG/CR-7197), cables (NUREG/CR-6931 and NUREG/CR-7010), and pumps, motors, and transformers (NUREG-2178, Volume 2). Transient ignition sources have not yet seen additional research targeting the realism of heat release rates. Since transient fires represent a significant fraction of the fire risk at nuclear power plants, there is value to the industry in improving the realism of how these fires are modeled.

This report documents testing performed to address this gap. The report begins by reviewing the existing guidance for transient fires and actual operating experience of U.S. nuclear power plants. These data were used to develop a large experimental program involving 99 transient fuel packages with repeat tests for a total of 290 tests. Data collected during the experimental program included heat release rate, heat of combustion, minor product yields, flame height, plume temperature, and heat flux. Test data were used to determine the vertical and horizontal zones of influence for each test and to assess the performance of the Fire Dynamics Tools (NUREG-1805) correlations for plume temperature, flame height, and heat flux.

A companion report will provide specific guidance on applying the test data to a FPRA.

Page Last Reviewed/Updated Tuesday, March 09, 2021