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The radiation resistance of epoxy compounds, solidified by crystalline hardening agents -metaphenylenediamine and phthalic anhydride -is investigated. It is shown that under conditions of γ irradiation (E = 1.33 MeV) the temperature of vitrification of the compounds depends on the dose (doses up to 1500 Mrad were investigated) and temperature 20-160°C, and the radiation gas release depends on the vitrification temperature and irradiation. It is shown that epoxy-phthalic anhydride compound is best as a matrix for immobilizing solid radioactive wastes at high temperatures (80-130°C). The experiments showed that the proposed compound can be recommended for immobilizing solid radioactive wastes.A great deal of attention is now being devoted to choosing the compounds for immobilizing radioactive wastes [1][2][3]. Epoxy compounds are promising materials for handling wastes, because such compounds possess high radiation resistance due to their content of aromatic groups [1]. The possibility of fixing radionuclides in reactor graphite by an epoxy oligomer, whose density was increased by heterocyclic aldehyde of the furan series with a filler and special-purpose additive, was demonstrated first in our country. The solidifying agents used for epoxy compounds are characterized by a crystalline and liquid aggregate state and radiation resistance. Solidifying agents such as polyethylene polyamine and polyamides are used, for example, in the immobilizing agent F and the Atomik compound, whose operational properties are described in [1]. The compounds of these solidifying agents are convenient to use because they do not require additional heating. However, the relatively low vitrification temperature (~60°C) gives rise to difficulties in using such compounds for immobilizing solid wastes, whose radiation heating exceeds 60°C. If the temperature of radiation heating exceeds 80°C, it has been suggested that compounds undergoing hot solidification be used, and metaphenylenediamine (a crystalline substance with a melting temperature of 63°C) and phthalic anhydride (a crystal substance with melting temperature 130°C) be used as the solidifying agent [4]. The wastes are solidified at temperatures not less than the melting temperature of the solidifying agent. Then the compound is in a low-viscous state and when solid wastes are immobilized it penetrates into the microcavities, forming a reliable matrix.The immobilizing agents for solid wastes must meet the following basic requirements: they must have high mechanical and adhesion strength, they must remain stable in water solutions, including solutions of acids and alkali, they must be in a glassy state under operating conditions, leaching of radionuclides should not exceed 10 -4 g/(cm 2 ·day), and the gas release should be minimal (not greater than 10 -8 -10 -9 cm 3 /(g·rad)). Under operating conditions, the deviation of the first four parameters should not decrease by more than 25%.The experiments showed that solidified epoxy compounds in a glassy state have high strength under comp...