The possibility is studied of using the heat of exothermal reactions in the solid phase for conditioning the ash residue produced when solid radioactive wastes are burned. It is shown that solidifcation of the ash wastes can be performed without input of energy from external heat sources with the final glassy product containing 50–60 mass % ash residue and meeting the requirements for solidified radioactive wastes. The conditioning is performed in a special crucible–container, intended not only for performing the process but also for subsequent storage or burial of the final product. 5 figures, 2 tables, 10 references.