Spent Fuel Transportation Risk Assessment, Final Report

The U.S. Nuclear Regulatory Commission (NRC) is responsible for issuing regulations for the
packaging of spent fuel (and other large quantities of radioactive material) for transport that
provide for public health and safety during transport (Title 10 of the Code of Federal Regulations
(10 CFR) Part 71, “Packaging and Transportation of Radioactive Waste,” dated
January 26, 2004). In September 1977, the NRC published NUREG-0170, “Final Environmental
Statement on the Transportation of Radioactive Material by Air and Other Modes,” which
assessed the adequacy of those regulations to provide safety assurance. In that assessment,
the measure of safety was the risk of radiation doses to the public under routine and accident
transport conditions, and the risk was found to be acceptable. Since that time, there have been
two affirmations of this conclusion for spent nuclear fuel (SNF) transportation, each using
improved tools and information. This report presents the results of a fourth investigation into the
safety of SNF transportation. The risks associated with SNF transportation come from the
radiation that the spent fuel emits, which is attenuated—but not eliminated—by the
transportation casks shielding and the possibility of the release of some quantity of radioactive
material during a severe accident. This investigation shows that the risk from the radiation
emitted from the casks is a small fraction of naturally occurring background radiation and the
risk from accidental release of radioactive material is several orders of magnitude less.
Because there have been only minor changes to the radioactive material transportation
regulations between NUREG-0170 and this risk assessment, the calculated dose caused by the
external radiation from the cask under routine transport conditions is similar to what was found
in earlier studies. The improved analysis tools and techniques, improved data availability, and a
reduction in uncertainty has made the estimate of accident risk from the release of radioactive
material in this study approximately five orders of magnitude less than what was estimated in
NUREG-0170. The results demonstrate that NRC regulations continue to provide adequate
protection of public health and safety during the transportation of SNF.