Effect of gray-body interchange factor and radiating temperature on the thermal response of the DT-18 shipping container

Some concerns and questions have been raised regarding the values of the DT-18 package surface emissivity, the emissivity of the B-1023 furnace used for thermal testing of DOE shipping packages, and the furnace radiating temperature that should be employed during thermal tests. In order for the thermal tests performed at the Y-12 Plan in Oak Ridge, Tennessee, to comply with the regulations specified in 10 CFR 71, it must be shown that a specific amount of heat is added to the package during the test. Therefore, a method of thermal analytical modeling was developed to calculate the quantity of heat energy input to which a DT-18 package is exposed during hypothetical accident scenario testing. Parametric studies involving the gray-body interchange factor (which embodies both the package and furnace emissivities) and the furnace radiating temperature were then performed, and the effects of these two variables on the net total heat received by a DT-18 package were determined. Based on the analyses presented in this report, simple guidelines and recommendations are made to order to ensure that thermal testing in the B-1023 furnace complies with federal regulations. Data are presented which allow the determination of an appropriate furnace surface temperature (800--850{degrees}C) based on the value of the gray-body interchange factor. The second alternative to ensure regulatory compliance involves allowing the DT-18 package to remain in the 800{degrees}C furnace for an additional amount of time (determined from presented data) beyond the required 30-min period