Uranium crystallization study with irradiated MOX fuel

Nomura, Kazunori  ; Nakahara, Masaumi; Yano, Kimihiko ; Sano, Yuichi   ; Shibata, Atsuhiro  ; Washiya, Tadahiro 

The uranium crystallization study has been carried out with various solutions. Several tens % of uranium was recovered from the simulated dissolver solution. As the results of the tests, pre-adjustment of the plutonium valence to (+4) was necessary to prevent plutonium co-crystallizing with uranium. Among the fission products, cesium behavior in some trials with the actual dissolver solution was different from that with the simulated dissolver solution. Decontamination factor of cesium to uranium crystals was about 100 in the simulated dissolver solution tests. From the other trials, however, it was suggested that the cesium was precipitated, and accompanied with uranium crystals. This cesium behavior is under investigation while the modification of the process conditions of the uranium crystallization and a new technology of crystal purification has been studying.