| 摘要 |
<p>An aqueous solution of irradiated uranium nuclear fuel is extracted with a solution of a tertiary or quaternary amine salt in an inert organic diluent to produce an organic extract containing the plutonium and an aqueous solution containing the uranium and fission products; plutonium is stripped from the organic solution, while the aqueous solution is dehydrated and fluorinated, the uranium fluoride being separated from fission product fluorides. Spent UO2 fuel clad in zirconium is dissolved in nitric acid and the solution extracted with a kerosene solution of trilaurylamine nitrate or the quaternary amine nitrate C6H5CH2N(CH3)2 -C12H23NO3. Other suitable organic diluents are xylene, CCl4, and nitromethane; the solution may contain a small amount of n-octyl alcohol. The aqueous solution containing U and fission products and free from Pu is evaporated and calcined, nitrous fumes given off being absorbed to re-form concentrated HNO3. The oxide residue may be fluorinated in the fluidized state either with hydrogen fluoride and fluorine in succession or with fluorine alone. The UF6 is separated from fission product fluorides by fractional distillation or by absorption on granular NaF.</p> |
