PROBABILITY OF PIPELINE OR RAILROAD FIRES AFFECTING SPENT NUCLEAR FUEL TRANSPORTATION CASKS

This paper estimates the likelihood that a pipeline break or a train fire could occur in the immediate vicinity of a spent nuclear fuel cask during rail transit. U. S. Department of Transportation databases are examined for information that yields likelihood estimates for such accidents. The results presented are intended to provide details and information in a form that is useful reference for future risk studies. Probabilities are calculated for both pipeline fires caused by pipeline breaks and for hazardous materials fires caused by train accidents. As an illustration, the resulting probabilities are used to calculate typical probabilities for fire accidents during rail transportation of spent fuel casks. For a single1600km (1000 mile) trip, the probability of a transportation cask being involved in a pipeline fire accident is about 9x10-22. Similarly, the probability of a cask being involved in a train fire accident during a single 1600km (1000 mile) trip is estimated to be about 3x10-7 . Because of the low likelihood but potentially severe thermal conditions caused by turbulent mixing of oxygen into the fire plume, pipeline accidents fall into the category of very low probability, high consequence accidents. For train transportation, the probability of a hazardous materials fire, assuming a typical freight train, is high enough to be considered in transportation risk assessments.