Thrce methods may be considered for reprocessing and burial of radioactive wastes with high radionuclide content: storage in tanks, burial in boreholes, and reprocessing into glass followed by stockpiling. Experience has been accumulated within the Mayak Combine on vitrification of wastes on an industrial scale using an electric melting furnace. The listed methods each have their own characteristic features. In our opinion, the most promising method is a one-step procedure. However, the reliability of the apparatus and their low throughput make it difficult to widely use them on an industrial scale. At the Gas Institute (Academy of Sciences of Ukraine), a converter type melting apparatus for reprocessing saltsaturated solutions was developed and studied at the end of the 1960's. A basic feature of this apparatus is that it burns the fuel (gas) directly in the melt, so a specific throughput is achieved which is many times higher than the throughput of tank melting furnaces. These apparatus have been successfully operated within various production processes. Because of the high specific throughput of the apparatus, in 1970 it was decided to conduct experiments on one-step reprocessing of high-level radioactive wastes in the form of solutions with salt concentrations up to 500 g/liter. A remote-controlled TOROS apparatus was developed to carry out the process (TOROS is the Russian acronym for thermal treatment of radioactive wastes by vitrification). In Fig. 1, we show the installatiOn on which the experiments were conducted for developing the TOROS apparatus, and also on which the characteristics of different types of gas-purifying devices were studied. The results of the investigations were then used to design a system to remove aerosols from waste gases for the vitrification electric furnace of the Mayak Industrial Association. Solutions of borosilicate and phosphate composition were used as model solutions. The work was done at the Mayak Industrial Association. The tests were done with a flow rate of 200-350 liters/h of the model solution, containing sodium and aluminum nitrates, phosphoric acid, and also 137Cs (0.01 mCi/liter), 9~ (0.1 mCi/liter), l~ (0.01 mCi/liter). In order to increase the concentration of these elements, the following stable isotopes were introduced into the solution (rag/liter): cesium 200, strontium 100, ruthenium 30-70. Before introduction into the model solution, the radionuclides and stable isotopes were converted to the chemical compounds in which they axe found in industrial solutions: cesium and strontium were converted to nitrates, ruthenium was converted to nitrosonitrates. The specific throughput of the apparatus was 0.8-1 m 3 of solution per square meter of the melt surface per hour. When performing the investigations on the pilot apparatus TOROS-2, data was obtained on the degree of fixation of the elements by the glass as a function of the design features of the melting apparatus, the glass founding technology, the level of the melt, and the conditions for feeding the solution into the melting chamber. It was established that the glass-former materials are taken up by 85-99%, cesium by 82-95%, strontium by 80-97%, ruthenium by 10-70%. The meltings allowed us to work up a design for the converter and the melt discharge unit water, to determine the flow rate for the coolant and the composition of the frit coating for creating a reliable lining, and also to determine the generation conditions and the characteristics of the aerosols formed. The experiments confLrrned the feasibility in principle of reprocessing wastes by vitrification in a converter type apparatus. Based on these data, it was decided to develop an industrial-scale model of the apparatus, TOROS-3k, which was considerably self-contained with longer operating life and allowed for remote control of the process of melting and discharge of the melt and the possibility of replacing the individual design elements (in particular, the torch), and also resulted in reduced entrainment of aerosols.