Uranium crystallization for dissolver solution of irradiated FBR MOX fuel

Yano, Kimihiko ; Shibata, Atsuhiro  ; Nomura, Kazunori  ; Koizumi, Tsutomu; Koyama, Tomozo

The uranium crystallization process has been developed as part of advanced aqueous reprocessing system. In the process, the great part of uranium is separated from the dissolver solution by crystallization as uranyl nitrate hydrate. The uranium crystallization test was carried out with the dissolver solution of irradiated FBR MOX fuel to investigate the influence of cooling rate on the crystal size and the behavior of fission products compared with that of tetravalent plutonium with the real dissolver solution. In regard to the influence of the cooling rate, it was obvious that the crystal size was smaller as the cooling ratio was faster. However, it was suggested that a large crystal produced by crystallization was always not high purity. Concerning the behavior of fission products, europium behaved similarly to tetravalent plutonium. Cesium accompanied with uranium into the crystals under the condition of this test.