Plutonium Air Transport Package Development for \"Worst-Case\" Accident

Sandia National Laboratories (SNL) has developed and tested a package design for air transport of plutonium that can survive a \"worst-case\" aircraft crash. This work has been performed for the Japan Nuclear Cycle Development Institute (JNC) using technology developed by SNL (US Patent 5,337,917) for the United States Department of Energy. U. S. law requires that air transport of plutonium through U.S. airspace from a foreign origin to a foreign destination must be in a packaging that is able to survive a \"worst-case\" aircraft crash. As a result, JNC has pursued the development of a design that can meet these stringent requirements. This report details the design and testing of a new plutonium air transport (PAT) package capable of protecting its contents in \"worst-case\" accident conditions. A potential \"worst-case\" accident is prescribed as a 282 m/s (925 ft/s) impact onto a decomposed rock surface. This is expected to be more severe than the current U.S. regulations that require a 129 m/s (422 ft/sec) impact onto a rigid surface. PAT packages currently certified in the U.S. were designed to meet the 129 m/s impact criteria in the U.S. regulations and use redwood as an impact-limiting material. The new design for transport of plutonium dioxide uses a non-flammable layered composite of aluminum perforated sheet and aramid cloth as an overpack to absorb kinetic impact energy and maintain confinement for subsequent fire protection. This design also uses a very robust primary containment vessel with a welded or brazed closure for protection and confinement of the contents. In addition, an outer shell around the energy absorbing material is provided for handling and weather protection. Package performance for end-on and side-on dynamic impact events was studied using 2D and 3D nonlinear finite-element codes. Half-scale models were fabricated and tested at the 3000-m rocket sled track at SNL. Side, end, and center-of-gravity-over-corner impact tests were performed. Results of these analyses and tests showed that the package design is capable of meeting the \"worstcase\" accident conditions and is more efficient than the current design as a result of its smaller overall volume and total mass.