TEMPERATURE RESPONSE OF A RAIL-CASK-SIZE PIPE CALORIMETER IN LARGE-SCALE POOL FIRES

The Container Analysis Fire Environment (CAFE) computer code is being developed at Sandia National Laboratories (SNL) to predict the response of massive spent nuclear fuel transport casks to a range of severe fire environments. It is designed for use in transportation risk and design studies. CAFE employs physics-based reaction chemistry and radiation heat transfer models that are appropriate for fuel-rich and highly sooty pool fires. These models allow CAFE to produce accurate fire heat transfer results even when relatively coarse (and fast running) computational grids are employed. Parameters for these models must be determined from large-scale fire test data. Three fire tests were performed at the SNL outdoor fire test facility to benchmark CAFE. In these tests, the interior surface of a 2.4 m diameter, 4.6 m long, and 2.5 cm thick pipe calorimeter was instrumented with 70 Type-K thermocouples. It was suspended above a 7.2 m diameter water pool with enough JP8 jet fuel on top to burn for up to 40 minutes. Heat flux gages, directional flow probes, thermocouples, and anemometers were used to characterize the environment in the vicinity of the calorimeter during and after the fire. Transient wind conditions and calorimeter temperatures were recorded during and after the fires. The average wind speed was roughly 0.8 m/s during the first test, 1.1 m/s during the second, and 2.6 m/s during the third. CAFE simulations were performed using the measured wind conditions as boundary conditions and a range of model parameters. The resulting calculated calorimeter temperatures are compared to the experimental measurements.