Spent Fuel Transportation Package Response Analyses to Severe Fire Accident Scenarios

This paper summarizes studies of truck and rail transport accidents involving fires, relative to regulatory requirements for shipment of commercial spent nuclear fuel (SNF). These studies were initiated by the U.S. Nuclear Regulatory Commission (NRC) in response to a 2006 National Academy of Sciences review of NRC’s procedures and regulations. The fire accident scenarios were based on the most severe historical railway and roadway fires in terms of their potential impact on SNF containers.The accident scenarios that were analyzed include one railway tunnel fire, two roadway tunnel fires, and one roadway with enclosed overpass fire. Analyses of the accident scenario fire conditions were performed with the Fire Dynamics Simulator (FDS) code. The fire conditions predicted with FDS for the various scenarios were then applied as thermal boundary conditions to numerical simulations of SNF packages. The peak temperatures of fuel cladding, containment seals, and other key packaging components are summarized, and dose and release consequences are discussed for each fire accident scenario.The combined summary of this work on fire accidents demonstrates that the current U.S. Nuclear Regulatory Commission regulations and packaging standards provide a high degree of protection to the public health and safety against release of radioactive material in real-world transportation accidents, were such events to involve SNF containers.