ANALYTICAL PREDICTION AND VERIFICATION OF HYDROGEN-AIR DEFLAGRATION PRESSURES RESULTING FROM TRANSURANIC WASTE RADIOLYSIS INSIDE OF SEALED CONTAINERS

Maintaining flammable gas concentrations below flammable limits in the layers of confinement of transuranic (TRU) waste is a limiting factor in the efficient Type B shipment of nuclear materials. Traditionally, flammable gas limits are maintained by limiting hydrogen generation due to radiolysis in the waste matrix, restricting the quantity of flammable volatile organic compounds in the container headspace, and implementing prohibitions on aerosol cans and large sealed containers. These restrictions have been driven by the requirements of 10CFR71.43(d) to ensure that no significant chemical reaction could occur among the packaging contents. The response of the Type B package containment boundary to pressures generated as a result of a deflagration event is of particular interest when evaluating alternatives to the restrictive payload controls traditionally implemented. An analytical method that utilizes the Cheetah? Thermo-chemical Kinetics code, developed by Lawrence Livermore National Laboratory, has been used to determine the deflagration pressures resulting from a stoichiometric hydrogen-air concentration inside of a sealed container under adiabatic constant volume assumptions. The adiabatic constant volume deflagration pressure is then adjusted to account for the void volume outside of the sealed container to determine the pressures exerted on the packaging containment boundary. A series of full-scale stoichiometric hydrogen-air deflagration tests have been performed to validate the analytical deflagration pressure prediction methodology. It is demonstrated that the analytical method can be utilized to conservatively predict the pressure that a sealed container of a given size and pressure capacity exerts on the packaging containment boundary when undergoing a stoichiometric hydrogen-air deflagration.