Activities of the Kharkov Institute Related to the Problem of Spent Nuclear Fuel Management

The National Science Centre Kharkov Institute of Physics and Technology (NSC KIPT) is one of the oldest and largest centers for science in Ukraine. For many years experts at NSC KIPT have carried out scientific and technological research in various areas of the nuclear industry. During the last 10 years special attention has been given to resolution of problems of radioactive waste (RAW) isolation. As a prospective method for RAW and spent nuclear fuel (SNF) management, encapsulation in a protective glass–ceramic form with a composition similar to natural minerals has been proposed. Research and development in the synthesis of crystal materials—titanates, zirconates, and alumino-silicates—is being performed. Actinides, and also strontium and cesium due to isomorphic replacements, can be located in the structure of these crystal materials. Technologies of obtaining these materials are based on methods of compacting, and sintering these powder materials under pressure. As initial components, industrial powders, the powders manufactured by grinding from natural rocks––the granite and clay, and also the powders obtained by chemical sedimentation of corresponding solutions of salts are used. Use of hot isostatic pressing (HIP) at the stage of sintering creates a material with a low coefficient for radionuclide diffusion and a low rate of leaching by ground water. The results of scientific and technological researches carried out at the NSC KIPT in the field of SNF isolation are presented and briefly discussed.