At the present time the primary problem in a closed nuclear fuel cycle is the management of high level liquid waste (HLLW) generated by the recovery of uranium and plutonium from spent nuclear fuel. Long-term storage of the HLLW, even in special storage facilities, poses a real threat of ecological accidents. This problem can be solved by incorporating the radioactive waste into solid fixed forms that minimize the potential for biosphere pollution by long-lived radionuclides and ensure ecologically acceptable safe storage, transportation, and disposal. In the present report, the advantages of a two-stage HLLW solidification process using a “cold” crucible induction melter (CCIM) are considered in comparison with a one-stage vitrification process in a ceramic melter.This paper describes the features of a process and equipment for a two-stage HLLW solidification technology using a “cold” crucible induction melter (CCIM) and identifies the advantages compared to a one-stage ceramic melter. A two-stage pilot facility and the technical characteristics of the equipment are described using a once-through evaporator and cold-crucible induction melter currently operational at the IA.Mayak. facility in Ozersk, Russia. The results of pilot-plant tests with simulated HLLW to produce a phosphate glass are described. Features of the new mineral-like waste form matrices synthesized by the CCIM method are also described. Subject to further development, the CCIM technology is planned to be used to solidify all accumulated HLLW at Mayak – first to produce borosilicate glass waste forms and then mineral-like waste forms.

CCIM technology allows syntheses of various materials over a wide range of compositions. This provides a means of applying the CCIM to the solidification of wastes obtained by different technologies of the spent nuclear fuel reprocessing, including toxic wastes containing heavy metals and those arising from fractionation. Solid compounds produced by this method meet both the requirements for their subsequent disposal in deep geological formations and spent fuel standards.On the basis of investigations into the REE and Uranium vitrification, the possibilities of CCIM immobilizing weapons Plutonium in preparation of glass compositions are considered.

The results of a complex of tests of refractories for glass resistance under static and dynamic conditions and the electric resistance during glass melting are presented.The tests of the refractories in a phosphate glass melt at 800-1100°C showed that the most stable material is the fusion-cast chromia-alumina-zirconia refractory ER-2161 with chromium oxide content 26 mass%. The pressed chromia-corundum refractory KhKT-10 possesses adequate glass resistance and is an electric insulator under the glass melting conditions in the ÉP-500 melter. On the basis of the results of comparative tests of chromia-containing refractories and Bakor-33, the refractories ER-2161 and KhKT-10 are recommended for the masonry of future furnaces as a material for the bridgewall and the electric-insulation layer in a two-layer threshold.Three ÉP-500 ceramic melters for vitrifying high-level liquid radioactive wastes have operated successfully for 20 years in the radiochemical plant RT-1 at the Mayak Industrial Association. Wastes with different composition and activitỹ 450 MCi are converted into phosphate glass by a single-stage method in these melters [1]. The main internal masonry of the ÉP-500 furnaces consists of bricks made of the baddeleyite-corundum refractory Bakor-33, which showed good glass resistance. However, elevated erosion of the refractory was observed in individual, most strongly attacked, sites of the masonrythe bridgewall and the threshold. The life span of these structures can be increased either by introducing water or air cooling or by using refractories with a higher glass resistance.The French company SEPR has obtained positive results by using fusion-cast chromia-alumina-zirconia refractories as the material for the bridgewall in glass-melting furnaces. Over the last 30 years, refractories such as ER-2161 (European analog) and Monofrax K-3 (American) have been widely used for the masonry in furnaces which are used for melting corrosive and high-temperature glasses. The operation of DWPF melters for vitrifying high-level liquid radioactive wastes from the nuclear weapons complex in Savannah River (USA) has shown that the life span of single-course masonry made of the refractory Monofrax K-3 in a borosilicate glass melt is 7-8 yr.In our country, an experimental batch of bricks consisting of fusion-cast KhATs-30 chromia-alumina-zirconia refractory, which was used for the masonry in the experimental ÉPBS-100 furnace at Mayak, was developed and fabricated. A comparative assessment of the KhATs-30 and Bakor-33 refractories after operation for 2 yr in a furnace confirmed that both refractories have a high-resistance to phosphate glass melt. However, because the KhATs-30 refractory is no longer produced,

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