Fire Dynamics Tools (FDTs) Quantitative Fire Hazard Analysis Methods for the U.S. Nuclear Regulatory Commission Fire Protection Inspection Program (NUREG-1805, Supplement 1, Volumes 1 & 2)

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Appendix: Simple Activity Flux

Publication Information

Manuscript Completed: June 2013
Date Published: July 2013

Prepared by:
D. Stroup*, G. Taylor*, G. Hausman**

*Office of Nuclear Regulatory Research
**Region III

M. H. Salley, NRC Project Manager

Prepared for:
Office of Nuclear Reactor Research
U.S. Nuclear Regulatory Commission
Washington, DC 20555-0001

Availability Notice

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NUREG-1805, Supplement 1, Volumes 1 & 2

NUREG-1805 Supplement 1, Volume 1 (PDF – 2.43 MB)
NUREG-1805 Supplement 1, Volume 2 – Appendices (PDF – 14.88 MB)


Spreadsheet Title English Units SI Units
Chapter 2.1 Predicting Hot Gas Layer Temperature and Smoke Layer Height in a Room Fire with Natural Ventilation    
Chapter 2.2 Predicting Hot Gas Layer Temperature in a Room Fire with Forced Ventilation    
Chapter 2.3 Predicting Hot Gas Layer Temperature in a Room Fire with Door Closed    
Chapter 3. Estimating Burning Characteristics of Liquid Pool Fire, Heat Release Rate, Burning Duration, and Flame Height    
Chapter 4. Estimating Wall Fire Flame Height    
Chapter 5.1 Estimating Radiant Heat Flux from Fire to a Target Fuel at Ground Level under Wind-Free Condition Point Source Radiation Model    
Chapter 5.2 Estimating Radiant Heat Flux from Fire to a Target Fuel at Ground Level in Presence of Wind (Tilted Flame) Solid Flame Radiation Model    
Chapter 5.3 Estimating Thermal Radiation from Hydrocarbon Fireballs    
Chapter 6. Estimating the Ignition Time of a Target Fuel Exposed to a Constant Radiative Heat Flux    
Chapter 7. Estimating the Full-Scale Heat Release Rate of a Cable Tray Fire    
Chapter 8. Estimating Burning Duration of Solid Combustibles    
Chapter 9. Estimating Centerline Temperature of a Buoyant Fire Plume    
Chapter 10. Estimating Sprinkler Response Time    
Chapter 13. Fire Severity Calculations    
Chapter 14. Estimating Pressure Rise Due to a Fire in a Closed Compartment    
Chapter 15. Estimating Pressure Increase and Explosive Energy Release Associated with Explosions    
Chapter 16. Calculating the Rate of Hydrogen Gas Generation in Battery Rooms    
Chapter 17.1 Estimating Thickness of Fire Protection Spray-Applied Coating for Structural Steel Beams (Substitution Correlation)    
Chapter 17.2 Estimating Fire Resistance Time of Steel Beams Protected by Fire Protection Insulation (Quasi-Steady-State Approach)    
Chapter 17.3 Estimating Fire Resistance Time of Steel Beams Protected by Fire Protection Insulation (Quasi-Steady-State Approach)    
Chapter 17.4 Estimating Fire Resistance Time of Unprotected Steel Beams (Quasi-steady-state Approach)    
Chapter 18 Estimating Visibility Through Smoke    
Chapter 19 Estimating the Thermally-Induced Electrical Failure (THIEF) of Cables    

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The U.S. Nuclear Regulatory Commission (NRC) has developed quantitative methods, known as "Fire Dynamics Tools" (FDTs), for analyzing the impact of fire and fire protection systems in nuclear power plants (NPPs). These methods have been implemented in spreadsheets and taught at the NRC's quarterly regional inspector workshops. The FDTs were developed using state-of-the-art fire dynamics equations and correlations that were preprogrammed and locked into Microsoft Excel® spreadsheets. These FDTs enable inspectors to perform quick, easy, firstorder calculations for potential fire scenarios using today's state-of-the-art principles of fire dynamics. Each FDTs spreadsheet also contains a list of the physical and thermal properties of the materials commonly encountered in NPPs.

This NUREG-series report documents a new spreadsheet that has been added to the FDTs suite and describes updates, corrections, and improvements to the existing spreadsheets. The majority of the original FDTs were developed using principles and information from the Society of Fire Protection Engineers (SFPE) Handbook of Fire Protection Engineering, the National Fire Protection Association (NFPA) Fire Protection Handbook, and other fire science literature. The new spreadsheet predicts the behavior of power cables, instrument cables, and control cables during a fire. The thermally-induced electrical failure (THIEF) model was developed by the National Institute of Standards and Technology (NIST) as part of the Cable Response to Live Fire (CAROLFIRE) program sponsored by the NRC. The experiments for CAROLFIRE were conducted at Sandia National Laboratories, Albuquerque, New Mexico. THIEF model predictions have been compared to experimental measurements of instrumented cables in a variety of configurations, and the results indicate that the model is an appropriate analysis tool for NPP applications. The accuracy and simplicity of the THIEF model have been shown to be comparable to that of the activation algorithms for various fire protection devices (e.g., sprinklers, heat and smoke detectors).

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