METHOD AND DEVICE FOR SOLIDIFYING LIQUID RADIOACTIVE WASTES Russian patent published in 2001 - IPC

FIELD: disposal of liquid radioactive wastes. SUBSTANCE: method involves primary treatment of wastes, their concentration and mixing up with fluxing additives, heating of mixture obtained, its melting, melt draining to tanks, and production of blocks. Concentration is effected by spray drying and calcination at 600-800 C. Used as fluxing additives are mineral- forming compounds taken in amount sufficient to obtain blocks in the form of mineral-like material of following group of minerals: aegirite, jadeite, aegirite-augite, arfvedsonite, orthite, schorlite, lovchorrite, andradite, or their mixtures. Fusion of this material is effected by its melting at 1250-1800 C with melt exposed to induction field. Device implementing proposed method (Fig. 1) has tank 1 holding liquid radioactive wastes, concentration apparatus 3, induction melter 16 incorporating water-cooled drain unit 19, tank 12 holding fluxing additives that incorporates dosing apparatus 13, mixer 11, exhaust gas decontaminating unit 9, pipelines, and valves. In addition, device is provided with high-temperature heat-insulated filter 8 and pipeline interconnecting concentration apparatus 3, mixer 11, and filter 8. Concentration apparatus is made in the form of externally heated cylindrical vessel mounted above melter; its top lid mounts spray nozzle 5 communicating with liquid-waste tank 1 and with compressed air source 2. Induction melter is made in the form of water-cooled crucible 16 whose side walls are transparent to variable electromagnetic field and whose bottom accommodates melting chamber 15 and drain chamber 17 intercommunicating in lower part of crucible. Melting chamber communicates through mixer 11 with concentration apparatus 3, filter 8, and flux dosing apparatus 13. EFFECT: improved safety of solidifying process and environmental friendliness in long-time storage of radioactive wastes. 7 cl, 2 dwg, 5 tbl