United States Nuclear Regulatory Commission - Protecting People and the Environment

Analysis of Severe Roadway Accidents Involving Long Duration Fires (NUREG/CR-7035)

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Publication Information

Manuscript Completed: December 2010
Date Published: February 2011

Prepared by:
G. Adams, T. Mintz

Center for Nuclear Waste Regulatory Analyses
6220 Culebra Road
San Antonio, TX 78228

C. Bajwa, NRC Project Manager

NRC Job Code J5639

Office of Nuclear Material Safety and Safeguards
U.S. Nuclear Regulatory Commission
Washington DC 20555-0001

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10 CFR Part 71 provides the regulatory requirements for the certification of transportation packages for spent nuclear fuel (SNF) and radioactive material. SNF packages are expected to be designed to endure a fully engulfing fire, as prescribed in 10 CFR Part 71. As a regulatory authority for transportation of radioactive materials, the U.S. Nuclear Regulatory Commission (NRC) ensures that packages designed to transport SNF meet the regulations prescribed in 10 CFR Part 71. The purpose of the study described in this report was to support NRC in determining the different types and frequency of roadway accidents involving severe, long duration fires that could impact roadway transport of SNF. Roadway accident data were examined from the U.S. Department of Transportation—Pipeline and Hazardous Materials Safety Administration. This study focused on those in-transit hazardous material (HAZMAT) accidents resulting in a fire that involved more than one vehicle. Such fires were analyzed to identify those that could have been severe enough to potentially affect an SNF package being transported on a roadway where the source of fuel for the fire would be from a vehicle not carrying the SNF package. From this study, the frequency of a severe fire occurring was estimated as roughly 4.90 × 10−5 accidents per million HAZMAT vehicle-km [7.89 × 10−5 accidents per million HAZMAT vehicle-mi]. This frequency represents 23 severe fire accidents occurring over the last 12 years (i.e., 1997 to 2008). None of the severe fire accidents involved the release of radioactive material. In general, severe fires are characterized by the release of flammable liquid (i.e., Class 3 HAZMAT), and in about 40 percent of the severe fires, more than 22,710 L [6,000 gal] of flammable liquid was released. Also, about half of the severe fires occurred on interstate highways with a median or divider and two of the severe fires occurred on interstate ramps. One of these accidents, occurring on a ramp, was likely in an enclosed area and as a result had the potential to generate a fire with higher average temperatures.

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