Loading Capacities for Uranium, Plutonium, and Neptunium in High Caustic Nuclear Waste Storage Tanks Containing Selected Sorbents

To evaluate the nuclear criticality safety in a typical nuclear waste storage tank, a study was initiated to measure the affinity of granular solids for plutonium, neptunium, and uranium from synthetic salt solutions and actual nuclear waste supernatant liquor. Granular solids such as activated carbon, hematite, and sodium phosphates, if present as sludge components in nuclear waste storage tanks, have been found to be capable of precipitating/sorbing actinides like plutonium, neptunium, and uranium from nuclear waste storage tank supernatant liquor.

Our results show that the removal of plutonium and neptunium from simulants by tank solid sludge components may be due to the presence of the activated carbon and metal oxides. Thus, the potential may exist for the accumulation of fissile materials in nuclear waste storage tanks containing trace levels of these radionuclides during lengthy nuclear waste storage and processing.