High-temperature methods for treating spent fuel cladding

The physical and chemical characteristics of the wastes from power plant fuel claddings are presented and high-temperature methods of preparing them for long-term storage are discussed. It is shown that a promising approach is that of conducting the operations of conditioning fuel cladding waste at the initial stages of reprocessing by thermal decladding of spent fuel elements. In this way: the fuel to be reprocessed is separated to the extent of 95-99% from the cladding material; gaseous and volatile fission products are eliminated; the cladding material is moulded into compact ingots suitable for long-term storage; insignificant quantities of fuel components and fission products go into the ingot; the main activity of the ingots is determined by the 60Co, 137Cs, 90Sr, etc. isotopes; the volume of solid and gaseous wastes are minimal and no liquid wastes are produced. It is also shown that it is advantageous to re-melt non-compact claddings to form ingots after the mechanical chopping and dissolving operations. This reduces the required waste storage volume by a factor of 1.5-3 and the metal surface by a factor of 1000, so that there is a considerable decrease in the surface contamination of the materials by fission products and a reduction in the surface diffusion of isotopes and their corrosion activity