Damage and thermal exposure of a radioactive material package in an accident and gasoline fire

A gasoline tanker collided with a stationary truck-transport carrying a load of general cargo including a lead shielded density gauge containing a 209 mCi cesium-137 sealed source. The ruptured tank ignited almost immediately. The ensuing fire destroyed both vehicles, two automobiles and a nearby restaurant-motel complex. Since the incident almost represents the hypothetical Type B thermal requirements, it was felt that a more detailed investigation of the case was warranted even though the package did not contain a Type B quantity of radioactive material. The cargo in the transport was subjected to the burning gasoline because the trucks remained in close proximity after the impact. All of the lead shielding (45 kg) became molten during the fire and escaped from the package through the shutter apparatus and bolt access holes giving a maximum gamma radiation dose rate of approximately 8 rem/h on the surface and 40 mrem/h at one meter. There was no loose contamination. From the presence of red and yellow lead oxides within the device it is estimated that the effect of the fire on the package was equivalent to that of a heat flux provided by a thermal environment of 5500C for 90 minutes to all surfaces of the package