Platinum Metals Rev., 1965, 9, (3), 89
Disposal of Radioactive Residues
Phosphate Glass Melted in Platinum-Lined Crucible
During the reprocessing of spent fuel elements from nuclear reactors, highly toxic radioactive fission products are accumulated as waste, which must be carefully stored and controlled for centuries. Glass is being studied as the medium for fixation at several establishments, and A. M. Piatt and C. R. Cooley of Battelle-Northwest, Richland, Washington—until recently the Hanford Laboratories operated by the General Electric Company—have now constructed a pilot plant for final demonstration of the techniques involved.
In one technique phosphoric acid is added to a concentrated waste. After further concentration by evaporation of nitric acid and water, the waste is fed into a platinum-lined melter operating at about 1250°C, which further reduces the volume and converts the residue to a molten glass. This overflows into a storage vessel and solidifies. By this means stable nuggets of glass have been produced that resist leaching and incorporate up to 95 per cent of the radioactivity present in the original liquid waste.