Crystallization of Uranium Complexes for Partitioning of Spent Nuclear Fuel

Abstract

Previous work in Germany and Japan has indicated that crystallization of uranyl nitrate at low temperatures from nitric acid solution could be a useful process for removing most of the uranium from spent light water reactor (LWR) fuel following the dissolution of the fuel in nitric acid. The crystallization process could potentially reduce the cost of LWR fuel partitioning because it selectively removes most of the uranium which is about 96% of the LWR spent fuel mass (metal basis). Subsequent separation processes would only need to handle the smaller volume of remaining actinides and the fission products. We are evaluating an approach to separating uranyl nitrate from spent fuel dissolver solutions by water and nitric acid distillation, a continuous adiabatic reduced-pressure crystallizer Initial work to define the process flowsheet and obtain data on optimum crystallization conditions and the purity of the uranium product are described.