| 摘要 |
<p>A process for the separation of neptunium from an organic phase, which is developed in the recovery of irradiated nuclear fuel and/or fertile material. The organic phase contains uranium-, plutonium- and neptunium ions, tritium in the form of tritiated water and fission products in ionic form, as well as an organic extraction agent dissolved in diluent. After a first wash step, and before the organic phase is further fed to a uranium-plutonium separation or to a uranium-plutonium coreextraction, the organic phase is brought into contact with an aqueous solution containing diluted HNO3, butyraldehyde and a low concentration of sulfamic acid in countercurrent flow as a second wash step for the selective reduction of Np (VI) to Np (V) and for selective stripping of Np (V), with respect to U and Pu, from the organic into an aqueous phase. The resulting aqueous phase charged with Np (V) and with portions of tritium and fission products is brought into contact with a solution of fresh extraction agent solution having a flow which corresponds to from 1/13.3 to 1/3.3 of the flow of the organic phase coming from the first wash step and to be decontaminated, to assure the selectivity of the stripping of Np (V) in reference to U and Pu. The aqueous phase resulting from this step and containing Np (V), T and fission products is then separated from the solution of fresh extraction agent.</p> |
