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According to the adopted international standards, any radioactive wastes must be buried in solid or solidified form. In our country the method of bituminization is most often used for solidifying low-and medium-level radioactive wastes formed at different stages of the nuclear fuel cycle. The bituminization process is also widely used in many countries with a developed nuclear power industry. At the present time, more than 20 industrial bituminization installations are operating at nuclear power plants and in nuclear centers in the USA, France, Sweden, Finland, Japan, Belgium, Mexico, Slovakia, Latvia, and other countries.In our country bituminization installations are operating at two nuclear power plants (Leningrad and Kalinin), two PZRO (Moscow Scientific and Industrial Association "Radon" and the Lenin Special Combine) and two SPRV VMF stations [1][2][3][4]. Assembly of equipment is being completed at the Balakov nuclear power plant. Three types of bituminization equipment are now being planned and tested: rotor-film, tubular, and an auger system. The first two types are in commercial operation, and the third type has passed the stage of commercial testing at the Novovoronezh nuclear power plant. It consists of two units: a concentrator of the flow-through evaporator type (UGU-400) and a two-auger mixer . In the course of the tests technological regimes that make it possible to obtain a homogeneous bituminous compound with a degree of filling of about 40 mass % with respect to the salts of the borate-containing solutions were determined.Investigations showed that the optimal regime is one in which a salt concentrate with a boiling point of 115-120~ i.e., moisture content -15-25 mass%, flows into the mixer from the flow-through evaporator. This also makes it possible to obtain an emulsion and subsequently a homogeneous compound. For a lower moisture content of the salt melt in the intrinsic crystal-hydrate water, a bituminous emulsion (water solution-bitumen) is not formed and the quality of the compound decreases. Moreover, stratification of the compound on cooling is observed.The TB-16 tubular bituminizer has been operating for about 16 years at the Special Leningrad Combine. It consists of a short tubular evaporator with forced mixing of the mass and two augers attached to a vertical shaft. The bituminizer has a separation zone with a mechanical entrainment trap. The process of bituminization is semicontinuous: When the required quantity of bitumen is fed once at the start of the process and with gradual feeding of the salt concentrate as it evaporates. The average feed rate of the concentrate is 300 liters/h. For a warming-vapor pressure of 0.6 MPa the average productivity of the apparatus is about 190 liters/h with respect to the evaporated moisture. An emulsion is produced thanks to vigorous mixing. The process can be separated into two stages: evaporation of the main mass of the water from the bitumen emulsion in the water solution and additional evaporation of the water from the emulsion into the bitum...

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