METHOD OF IMMOBILIZATION OF RADIONUCLIDES CS+ IN ALUMINOSILICATE CERAMICS Russian patent published in 2018 - IPC C04B35/19 G21F9/16 A61N5/10 

FIELD: technological processes.

SUBSTANCE: invention relates to methods for immobilizing radionuclides in ceramics and is intended for the stable immobilization and long-term preservation of radioactive waste, including nuclear waste, spent sorbents containing radionuclides, and can also find application in the radiochemical industry in the manufacture of sources of ionizing radiation for use in gamma-defectoscopy, measurement technology, medicine, including sources of ionizing radiation with strictly dosage specific activity for use in oncology. According to the method of the invention, ground natural zeolite with a Na₂O content of 1.55–2.15 wt. % saturated with cesium ions are placed in a graphite or steel mold, are pressed and subjected to spark plasma sintering in a vacuum chamber under a constant mechanical load under the influence of high-energy low-voltage pulses of unipolar electric current with a duration of 3.3 ms, that are generated by packets with pauses between them. Temperature of the sintered powder is increased to 800–1,100 °C in two stages: in the range up to 650 °C, the heating rate is 300 °C/min, above 650–90 °C/min. Hold mold with zeolite powder at the achieved temperature for 4.5–5.5 minutes, then, keeping the vacuum, cool it to ambient temperature. In the manufacture of sources of ionizing radiation, the original zeolite is washed before grinding, after grinding a fraction of 0.05–0.1 mm is selected which is again washed and dried before sintering.

EFFECT: increase in the number of immobilized cesium radionuclides in ceramic matrix, which provides for an increase in the specific activity and, accordingly, safety in the disposal of radwaste, while expanding the scope of use of the products obtained.

4 cl, 3 dwg, 3 ex