METHOD FOR PROCESSING USED NUCLEAR FUEL

The proposed method for processing used nuclear fuel implies processing the fuel by fluorine or fluorine-containing substance. According to the proposed method, the processing of the used fuel by gaseous fluorine is accomplished at two stages. At the first stage, 89 ... 90 % of uranium haxafluoride are removed. At the second stage, uranium haxafluoride and plutonium are mixed in a fluorination unit at a temperature of 300 ... 800 ?C, with the removal of heat, which is released in chemical reaction, by removing the gaseous product of the fluorination reaction and cooling the product by heat carrier. The cooled gaseous product is returned to the fluorination unit. In the processing, operations are performed for removing oxygen, produced at the first processing stage due to the difference of the temperatures at which oxygen and fluorides are released in the fluorination reaction, rectifying fissionable actinoides from the fluorides that are present in the fission products, reducing the fluorides in the low-temperature melt of ternary fluoride salts at a temperature of 500 ... 550 ?C, with the removal of elementary fluorine, at an inert anode, and powder-like actinoids at a melted zinc cathode, vacuum separation of zink from the powder-like actinoids, oxidation of the released actinoids by air, praparing mixed fuel from uranium and plutonium, and immobilizing all the gaseous and solid fluorides in silicon melt at a temperature of 1420 ... 1450 ?C.