Removal of liquid and solid impurities from uranyl nitrate hexahydrate crystalline particles in crystal purification process

Masaumi Nakahara, Kazunori Nomura, Tadahiro Washiya, Takahiro Chikazawa, Izumi Hirasawa

    Research output: Contribution to journalArticle

    Abstract

    The purification behavior of uranyl nitrate hexahydrate (UNH) was investigated to evaluate the decontamination performance of liquid and solid impurities using a dissolver solution of mixed oxide (MOX) fuel in batch experiments. The UNH crystal recovered from the MOX fuel dissolver solution containing simulated fission products (FPs) was purified by a sweating and melt filtration process. Although the decontamination factors (DFs) of Pu, Cs, and Ba did not change in the sweating process, that of Eu increased with increases in temperature and time. These results indicate that liquid impurities such as Eu were effectively removed by the sweating method, but solid impurities such as Pu, Cs, and Ba were minimally affected in the batch experiments. On the other hand, the DF of Ba increased with 0.45 and 5.0 μ filters in the melt filtration process. Since Pu and Cs formed as Cs2Pu(NO3)6 in the course of U crystallization and was accompanied with the UNH crystal, these behaviors were similar to each other. Although the DFs of Pu and Cs did not change with the 5.0 μ filter, it increased approximately twofold with the 0.45 μ filter. The particle size of Cs2Pu(NO3)6 is relatively small and might pass through the 5.0 μ filter in the melt filtration process. The liquid impurities as Eu remained in the molten UNH crystal with some filters.

    Original languageEnglish
    Pages (from-to)322-329
    Number of pages8
    JournalJournal of Nuclear Science and Technology
    Volume48
    Issue number3
    DOIs
    Publication statusPublished - 2011

    Keywords

    • Barium
    • Cesium
    • Crystal purification
    • Crystallization
    • Europium
    • Melt filtration
    • Mixed oxide fuel
    • Plutonium
    • Sweating
    • Uranyl nitrate hexahydrate

    ASJC Scopus subject areas

    • Nuclear and High Energy Physics
    • Nuclear Energy and Engineering

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