Treatment and Volume Reduction of Transuranic Waste at the Los Alamos National Laboratory Plutonium Facility

Abstract

Los Alamos National Laboratory (LANL) is one of two design laboratories in the United States Department of Energy’s (DOE) weapons complex, with over 60 years of experience in handling radioactive materials and, consequently, in radioactive waste management. The focus for actinide research and development is the Plutonium Facility, which has been in operation since 1978. The Nuclear Materials Technology (NMT) Division is responsible for operating the Plutonium Facility. It has a dedicated group of personnel who manage radioactive and hazardous waste, and address environmental regulations. Waste from operations with radioactive materials inside glovebox lines in the Plutonium Facility is packaged for disposal in the Waste Isolation Pilot Plant (WIPP) in Carlsbad, New Mexico. This waste is subject to a prescriptive certification program and is expensive to dispose of. Because the Plutonium Facility generates approximately 140 cubic meters of transuranic (TRU) waste each year, this significant financial burden effectively reduces the funds available to conduct research. To cut waste disposal costs, the NMT Division is making a considerable effort to identify and fund implementation of treatment and size-reduction processes. This study looks at both the effectiveness and probability of successful implementation. The waste management group’s waste minimization specialist has used waste generation information to identify the two largest TRU waste streams: combustible solids would benefit from size reduction, and nonactinide metals can be decontaminated. To reduce the size of combustible solids (polyethylene bottles and rubber hose), an industrial-model granulator, which was purchased for the head end of a molten salt oxidation process, is being adapted. This waste stream can be reduced by about 30% without affecting the ability to perform nuclear material assay. For glovebox decontamination, electrolytic decontamination techniques previously developed will also work on metals (tubing, tools, and equipment). Reducing the TRU levels to low-level contamination will allow onsite disposal, significantly reducing disposal costs (by approximately an order of magnitude). Several other technologies that were developed to address environmental regulatory concerns will also result in modest waste minimization and are in various states of installation and testing; they are vitrification for aqueous TRU waste, pyrolysis for the destruction of mixed waste, and distillation and recycle for nitric acid and trichloroethylene. The successful implementation and coordination of waste minimization and treatment technologies is resulting in cost savings from waste reduction and avoidance for the NMT Division.