Dealing with highly active wastes formed in nuclear-fuel regeneration

The basic approach to dealing with highly active liquid wastes formed in nuclear fuel regeneration in the USSR consists of solidification of the wastes, intermediate storage of the solidified wastes, and subsequent removal to geological formations. Several technological schemes for solidification are at the scientific-research and the industrial-prototype stages. The process which has been most studied is the production of phosphate and borosilicate glasslike materials in a ceramic melting unit without preliminary calcination. Technological schemes and apparatus with preliminary calcination of the wastes are also at the experimental testing stage. Three types of apparatus are under tests: a fluidized bed apparatus, an atomizing calcinator with spraying through an atomizer into a heated metallic chamber, and a rotating horizontal bed calcinator. These processes are discussed from the standpoints of productivity, automation and control, waste composition and containment, corrosion, and matrix materials research and behavior under dehydration, calcination, melting, vitrification, and radionuclide leaching conditions. Burial proposals and site studies are also assessed