METHOD OF PURIFICATION OF URANYL NITRATE THE FISSION PRODUCTS AND A DEVICE FOR ITS REALIZATION Russian patent published in 2006 - IPC G21C19/46 B01D9/02 C01G43/00 

FIELD: processing of the waste nuclear fuel.

SUBSTANCE: the invention is pertaining to the field of processing of the waste nuclear fuel, in particular to the method and for purification of the waste nuclear fuel from the fission products and a device for its realization. The invention provides, that uranyl nitrate solution is evaporated up to the concentration in respect to uranium of 800-1300 g/l and to nitric acid of 0.5-3.0 mole/l. Crystallization is conducted in a forward flow of the being formed crystals of hexahydrate of uranyl nitrate and a mother liquor at constant chilling of the solution up to temperature of 15-30°C. The formed crystals are separated from the mother liquor and subjected to the countercurrent washdown at the temperature of 15-30°C by a washing solution containing 250-300 g/l of uranium and 3.0-6.0 mole/l of nitric acid. Then the crystals are separated from the washing solution, smelt at the temperature exceeding 60°C and discharge under the action of a difference of the hydrostatic pressure. The for purification of uranyl nitrate from the fissing products contains a crystallizer made in the form of a pipe with external chilling and supplied with the union of the uranyl nitrate solution feeding. The device has the U-shaped form and is mounted upright. On one side of the device in its upper part there is a crystallizer with a union for uranyl nitrate solution feeding. The lower part of the crystallizer is mounted coaxially to the washing column. The cover is supplied with a union for a joint withdrawal of the mother liquor and the spent washing solutions. The lower part of the washing column has a conical bottom and is supplied by the union of feeding a washing solution. The other side of the device is made in the form of the pipeline. In the lower part the pipeline is connected to the conical bottom of the washing column and a pulsation cylindrical chamber, and in the upper part the pipeline is supplied by a drain connection. Advantages of the invention consist in simplification of the method and improved degree of a purification efficiency.

EFFECT: the invention ensure simplification of the method and an improved degree of purification efficiency.

5 cl, 2 dwg, 2 ex