Isolation of Separated Waste of Nuclear Industry

The reprocessing of spent nuclear fuel (SNF) of nuclear power plants leads to the generation of radioactive waste (RW), including high level waste (HLW). HLW contains hazardous long-lived fission products and actinides, therefore, the creation of effective methods of handling it is the main task of the final stage of the closed nuclear fuel cycle. At present, HLW is immobilised in Na–B–Si or Na–Al–P glasses, which does not meet the requirements of safety and economic efficiency. In particular, the low content of waste (3–20 wt %) in the glasses worsens the use of the deep storage space for HLW. Over time, the glasses crystallize with increasing solubility of the matrix in groundwater. The solution to the problem of handling HLW is related to the separation of radionuclides onto fractions. Many of these techniques have already been tested on real liquid waste from SNF reprocessing. As a result, fractions of elements can be obtained for immobilisation in optimal matrices with crystalline (mineral-like) phases. Compounds with structures of pyrochlore, zirconolite, monazite, brannerite, perovskite, britholite, murataite, garnet are suitable for incorporating actinides. For Cs and Sr, phases with the structures of hollandite, pollucite, perovskite, and langbeinite are proposed. Glass crystalline materials (glassceramics) are optimal for isolating wastes of the complex composition. Given the methods for the synthesis of HLW matrices and promising technologies for their industrial production are considered.