Benchmark of a Fast-Running Computational Tool for Analysis of Massive Radioactive Material Packages in Fire Environments

Journal of Fire Protection Engineering

Suo-Anttila³

2011

Previously, the US Nuclear Regulatory Commission performed simulations using fire dynamics simulator (FDS) software to predict the response of spent nuclear fuel transport packages in severe naturally ventilated tunnel fires. The long-range objective of the authors' current project is to predict the response of such a package to those tunnel fires using different computational methods. The first stage of the project, which is the subject of this article, is to determine the accuracy of Container Analysis Fire Environment (CAFE) computer simulations in predicting gas speed and temperature measurements made in forced-ventilated and naturally ventilated fires from the Memorial tunnel test series performed for the Massachusetts Highway Department in the 1990s. The CAFE simulations accurately predict the average heat release rate in both types of tests. Gas speeds and temperatures are obtained from the simulations at the same locations as for the measurements. For the forced-ventilated test, CAFE predicts those quantities more accurately upstream of the fire than downstream. In addition, the predictions are less accurate for the naturally ventilated test than they are for the forced-ventilated experiment. However, the accuracy of the CAFE prediction in the naturally ventilated test is on par with that from FDS.

Section: Container Analysis Fire Environment Simulationsmentioning

confidence: 99%

Benchmarking of Container Analysis Fire Environment simulation using the memorial tunnel fire ventilation tests

Chalasani¹,

Journal of Fire Protection Engineering

Suo-Anttila³

2011

“…The calorimeter interior surface temperatures and external wind conditions were measured during and after a series of roughly 30-minute fires. CAFE simulations were performed using computational domains that modeled the experimental facility, and the measured wind conditions as boundary conditions [10][11][12]. These simulations were performed with different parameters for the physics-based models.…”

Section: Introductionmentioning

confidence: 99%

Validation of Container Analysis Fire Environment (CAFE) Code for Memorial Tunnel Fire Ventilation Test Program

Chalasani

ASME 2010 Pressure Vessels and Piping Conference: Volume 7

Suo-Anttila³

2010

Self Cite

The Container Analysis Fire Environment (CAFE) computer code was developed at Sandia National Laboratories to predict the response of spent nuclear fuel (SNF) transport packages in large fires. CAFE's fire model has been benchmarked using measurements from large, unconfined outdoor fires. In the current work CAFE simulations are benchmarked using data acquired in two fires from the Memorial Tunnel test series. The Memorial Tunnel, a decommissioned highway tunnel in West Virginia, is 850 m (2,800 ft) long, 4.38 m (14.3 ft) wide, and has a 3.2% slope. In both fires, the time-dependent air temperature and speed were measured at several locations throughout the tunnel during 50 MW fires. The first test used forced ventilation and the upper portal of the tunnel was sealed. Shortly after the fire started, air was forced into the tunnel at a location between the sealed portal and the fire, forcing the air flow toward the lower portal. The second test used natural ventilation, in that both portals were open and there was no forced flow. However, wind outside the tunnel appeared to cause a net flow inside, even before the fire started. While the Memorial Tunnel Fire test conditions and results were well documents, some details were not available to the current authors. This necessitated the used of some assumptions. CAFE simulations accurately reproduced many of the characteristics of the temporal and spatial variation of the measured air speed and temperature. The maximum simulated temperatures for the forced and naturally ventilated tests were, respectively, 26 o F (14 o C) and 201 o F (94 o C) below the corresponding measured values. This work will be used to assess the accuracy of CAFE in predicting the likely response of SNF packages in historic transportation tunnel fires.

“…ISIS-3D simulations have been benchmarked against experiments that measure the response of large pipe calorimeters to hydrocarbon pool fires [7,8]. These works show that ISIS-3D accurately reproduces measurements for different calorimeter sizes and placements relative to the fuel pool, and for a variety of wind conditions.…”

Section: Introductionmentioning

confidence: 99%

Radiation Heat Transfer and Reaction Chemistry Models for Risk Assessment Compatible Fire Simulations

Journal of Fire Protection Engineering

2006

Risk assessment studies for hazardous material packages require fire response prediction tools that are both accurate and rapid. This article describes the theoretically based, semiempirical reaction chemistry and radiation heat transfer models for large, optically dense pool fires incorporated in the ISIS-3D CFD software. The chemistry model employs four separate reactions (two produce radiating soot). The heat transfer model divides the computational domain into the diffusely radiative fire and its nonparticipating environment. ISIS-3D simulations are performed on a 6-m square JP8 pool fire experiment in which the soot temperature and volume fraction are measured. The reaction rate and soot formation parameters of the chemistry model are determined based on a comparison of the simulation with the measured data. Simulations are then performed on an experiment that measures the temperature of a pipe calorimeter suspended over the leeside of a 19-m-diameter JP8 fuel pool fire with a 9.5 m/s crosswind. The soot volume fraction that the heat transfer model uses to define the edge of the diffusely radiating fire is determined based on a comparison with the measured average temperature of the calorimeter. That simulation accurately predicts the calorimeter spatial temperature variation without further adjustment. ISIS-3D is not fully predictive, should not be used far outside the range of conditions in which its parameters are determined (JP8 pool fires larger than 2 m), and is not intended to replace the fundamental fire physics software. However, it demonstrates highly accurate results with rapid turnaround times for a range of conditions that are relevant to large hazardous material transport packages in severe fire conditions.