Pu(VI) Nitrate crystallization behavior confirmation experiment

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Crystallization procedure is considered to have an advantage in recovering rather pure uranium from contaminated uranium solution and to be applicable for a new reprocessing process. It is considered necessary to collect data for Pu crystallization for design of the process with crystallization procedure. Last year the test for Pu(IV) nitrate erystallization was performed and it was confirmed that Pu crystallization is not observed under supposed crystallization condition if Pu valence is adjusted to 4. In this study, two type beaker tests were performed, (1)Pu(VI) nitrate crystallization test to confirm a behavior of Pu(VI) nitrate under crystallization condition. (2)U-Pu(VI) nitrate crystallization test to confirm a U-Pu(VI) co-crystallization phenomena. These tests were performed in AEA Technology Harwell Laboratory and the results were examined by Mitsubishi Materials Corporation. Test results were as follows. (1)Pu(VI) crystallization test. (a)Pu(VI) nitrate solution of 200, 100 and 50 gPu/L with HNO 6M were cooled down up to -60C to confirm Pu(VI) nitrate crystallization or freezing of the solution. (b)Crystal of HO and HNO 3HO were observed but Pu(VI) nitrate crystallization was not observed. (c)We can estimate that Pu(VI) nitrate crystallization will not occurred in the reprocessing process with crystallization procedure. (2) U-Pu(VI) nitrate crystallization test. (a)U-Pu(VI) mixed nitrate solution is cooled to 10C and 0C. (b)U-Pu(VI) co-crystallization was confirmed by orange colored crystal in both cooling temperatures. (c) It is considered that Pu(VI) nitrate crystal is co-crystallized with uranyl nitrate crystal by the following reasons. cdot$ crystal form is same and lattice paramters are very near. (d)U+Pu(VI) crystallization data is very near with uranyl nitrate crystallization data if Pu(VI) nitrate is considered to be crystallized ...