**5.3 Continuous operation with uranyl nitrate solution using kureha crystal purifier**

The crystal purification experiments with the KCP were carried out using the UNH crystal recovered from uranyl nitrate solution containing Sr of SUS304L (Yano et al., 2009). Although the DF of liquid impurities, Eu, in the static system was approximately 2.4 at 60°C for 30 min, the DF of Sr was 50 by the KCP. The liquid impurities such as Sr was removed from the UNH crystal not only by the sweating phenomenon but also by washing with U reflux melt, which was produced by the melter at the top of the column of the KCP. On the other hand, the DF of solid impurities, SUS304L, achieved a value of 100 with the KCP. In the static system, the solid impurities remained in the UNH crystal after the sweating operation. In the KCP, the solid impurities were removed from the UNH crystals due to upward movement of the crude crystals from the double screw conveyors; the UNH crystals and solid impurities, which have different densities and particle sizes, separate from each other by gravity and mixing.
