Hydrothermal oxidation of radioactive combustible waste

A hydrothermal processing system was designed, built and tested for treatment of transuranic combustible material. The operation is performed in a plutonium glovebox. Presented in this paper are results from the study of the hydrothermal oxidation of plutonium and americium contaminated organic wastes. The use of thermal liquefaction, via pyrolysis, to prepare solid materials for hydrothermal processing was tested and compared to the pumping of slurries of small particle sized solids (ion exchange resin). Experiments show that the hydrothermal process converts greater than 99.9% of the organic component to CO2 and H2O, with 30 wt% H2O2 as an oxidant, at 540°C and 46.2 MPa. The majority of the actinide component forms insoluble products that are easily separated by filtration. A titanium liner in the reactor and heat exchanger provides corrosion resistance for the oxidation of chlorinated organics.