Transportation Accident Response of a High-Capacity Truck Cask for Spent Fuel*

The recent GA-4 cask design was developed by General Atomics (GA 1994) as part of the OOE-OCRWM's Cask System Development Program for high-capacity shipping casks. The GA-4 design differs from earlier truck cask designs in its high capacity and non-cylindrical cross section as well as in other design details and material choices. Several earlier studies [in particular NRC {1977) Final Environmental Suuement on the Transportation of Radioactive Material by Air and Other Modes and (Fischer 1986) (referred to as the Modal Study)] examined the performance of spent nuclear fuel transportation casks in a wide range of potential transportation accidents. The earlier studies addressed the possibility that some parameter values of real accidents might exceed those values prescribed for design-basis accidents in regulations (10 CFR 71). The present study analyzes the response of the GA-4 truck cask for a similar range of potential accidents. Two of the primary goals of this study were (i) to check the structural and thermal performance of the GA-4 cask in a broad range of accidents and (ii) to carry out a severe-accidents analysis as had been addressed in the Modal Study but now using a specific recent cask design and using current-generation computer models and capabilities. At the same time, it was desired to compare the accident performance of the GA-4 cask to that of the generic truck cask analyzed in the Modal Study.