| 摘要 |
The invention relates to a process for preparing a purified uranium compound from uranium dioxide waste obtained from spent fuel pellets used in nuclear reactors and made by compressing, sintering and grinding uranium dioxide. In the process according to the invention, this is achieved by dissolving the uranium dioxide of the waste in an acid, which gives a solution of a uranyl salt of the acid. Any undissolved impurities are removed, and the uranium is precipitated out of the solution in the form of ammonium diuranate, using urea. The dissolved impurities stay in solution here. The ammonium diuranate is separated off from the solution and is dissolved in an acid either in the form in which it is obtained or in the form of a uranium oxide into which it is converted. This gives a solution of a uranyl salt of the acid. The uranium present in this solution is precipitated out in the form of ammonium uranyl carbonate. The latter is then separated from the solution, leaving behind the dissolved impurities in the solution. The resulting ammonium uranyl carbonate is suitably converted into uranium dioxide for use in the preparation of new fuel pellets for nuclear reactors. |
