Robust Solution to Difficult Hydrogen Issues When Shipping Transuranic Waste to the Waste Isolation Pilot Plant

The Waste Isolation Pilot Plant (WIPP) has been open, receiving, and disposing of transuranic (TRU) waste since March 26, 1999. The majority of the waste has a path forward for shipment to and disposal at the WIPP, but there are about two percent (2%) or approximately 3,020 cubic meters (m{sup 3}) of the volume of TRU waste (high wattage TRU waste) that is not shippable because of gas generation limits set by the U.S. Nuclear Regulatory Commission (NRC). This waste includes plutonium-238 waste, solidified organic waste, and other high plutonium-239 wastes. Flammable gases are potentially generated during transport of TRU waste by the radiolysis of hydrogenous materials and therefore, the concentration at the end of the shipping period must be predicted. Two options are currently available to TRU waste sites for solving this problem: (1) gas generation testing on each drum, and (2) waste form modification by repackaging and/or treatment. Repackaging some of the high wattage waste may require up to 20:1 drum increase to meet the gas generation limits of less than five percent (5%) hydrogen in the inner most layer of confinement (the layer closest to the waste). (This is the limit set by the NRC.) These options increase waste handling and transportation risks and there are high costs and potential worker exposure associated with repackaging this high-wattage TRU waste. The U.S. Department of Energy (DOE)'s Carlsbad Field Office (CBFO) is pursuing a twofold approach to develop a shipping path for these wastes. They are: regulatory change and technology development. For the regulatory change, a more detailed knowledge of the high wattage waste (e.g., void volumes, gas generation potential of specific chemical constituents) may allow refinement of the current assumptions in the gas generation model for Safety Analysis Reports for Packaging for Contact-Handled (CH) TRU waste. For technology development, one of the options being pursued is the use of a robust container, the ARROW-PAK{trademark} System. (1) The ARROW-PAK{trademark} is a macroencapsulation treatment technology, developed by Boh Environmental, LLC, New Orleans, Louisiana. This technology has been designed to withstand any unexpected hydrogen deflagration (i.e. no consequence) and other benefits such as criticality control