United States Nuclear Regulatory Commission - Protecting People and the Environment

Refining And Characterizing Heat Release Rates From Electrical Enclosures During Fire (RACHELLE-FIRE) — Volume 2: Fire Modeling Guidance for Electrical Cabinets, Electric motors, Indoor Dry Transformers, and the Main Control Board (NUREG-2178, Volume 2, EPRI 3002016052)

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Publication Information

Manuscript Completed: December 2019
Date Published: June 2020

EPRI Project Manager
A. Lindeman

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

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

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

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Abstract

NUREG–2178 Volume 1 refined the heat release rates (HRRs) associated with electrical cabinets and introduced an obstructed fire plume model for refining the vertical zone of influence (ZOI). As a result, Volume 1 has been implemented in a number of nuclear power plant fire probabilistic risk assessments to obtain a more realistic estimate of risk associated with electrical cabinet fires. Although the methodology in Volume 1 is focused on data analysis and the ZOI, it was realized that modeling refinements associated with other aspects of cabinet fires and other electrical ignition sources should be investigated. These targeted areas are further investigated in this report.

This report describes improved methods that will increase the realism in the modeling of selected ignition sources. The areas further investigated include the treatment of flame radiation and obstructed radiation, fire propagation between adjacent electrical cabinets, HRRs for electric motors and dry transformers, fire location factor, and the modeling of the main control board.

Keywords
Fire probabilistic risk assessment
Fire modeling
Fire Dynamics Simulator
Heat release rate
Obstructed fire plume
Zone of influence

Page Last Reviewed/Updated Monday, June 22, 2020