JOPSS - Search Results

Journal Articles

ZMH crystals addition to prevent ZMH encrustation in Mo-Zr-Te HNO $_{3}$ solution

Sue, Kasumi*; Kamoi, Kensuke*; Takeuchi, Masayuki; Miyazaki, Yasunori; Hirasawa, Izumi*

Progress in Nuclear Science and Technology (Internet), 7, p.351 - 356, 2025/03

https://doi.org/10.15669/pnst.7.351

no abstracts in English

Journal Articles

Encrustation prevention of zirconium molybdate hydrate

Arai, Takahiro*; Ito, Daiyu*; Hirasawa, Izumi*; Miyazaki, Yasunori; Takeuchi, Masayuki

Chemical Engineering & Technology, 41(6), p.1199 - 1204, 2018/06

https://doi.org/10.1002/ceat.201700663

Times Cited Count：6 Percentile：18.89(Engineering, Chemical)

In reprocessing process, spent nuclear fuel is dissolved by HNO $_{3}$ . Mo and Zr in the acidic solution react to form zirconium molybdate hydrate (ZMH). ZMH adheres to the inner-surface of reprocessing equipment, giving a great influence on stable operation. Conventional anti-encrustation is achieved by cleaning the surface of the reprocessing equipment by high pressure water and dissolving wall deposits by acid or alkaline solution. However, the former increases radioactive waste volume, and the latter contributes to corrosion of the metal surface. In this study, encrustation mechanism of ZMH crystal was investigated based on the deposited mass on the solid surface. Observing the deposition process, it was clarified that ZMH fine crystal growth is accelerated and agglomerated, followed by the rapid deposition. Total deposited mass decreased not only by lowering initial ratio of Mo and Zr concentration under the range of 1.0 Mo/Zr 2.0, but also by lowering HNO $_{3}$ concentration.

Journal Articles

Purification of uranium products in crystallization system for nuclear fuel reprocessing

Takeuchi, Masayuki; Yano, Kimihiko; Shibata, Atsuhiro; Sambommatsu, Yuji*; Nakamura, Kazuhito*; Chikazawa, Takahiro*; Hirasawa, Izumi*

Journal of Nuclear Science and Technology, 53(4), p.521 - 528, 2016/04

https://doi.org/10.1080/00223131.2015.1060907

Times Cited Count：3 Percentile：23.64(Nuclear Science & Technology)

Journal Articles

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

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

Journal of Nuclear Science and Technology, 48(3), p.322 - 329, 2011/03

https://doi.org/10.3327/jnst.48.322

Times Cited Count：9 Percentile：49.59(Nuclear Science & Technology)

The purification behavior of uranyl nitrate hexahydrate was investigated to evaluate the decontamination performance of liquid and solid impurities using a dissolver solution of mixed oxide fuel in batch experiments by the sweating and the melt filtration processes. Liquid impurities such as Eu were effectively removed by the sweating method, but solid impurities such as Pu, Cs and Ba were affected a little in the batch experiments. On the other hand, the decontamination factor of Ba increased with 0.45 and 5.0 m filters in the melt filtration process. Although the decontamination factors of Pu and Cs did not change with 5.0 m filter, it increased approximately two-fold with 0.45 m filter. The particle size of Cs $_{2}$ Pu(NO $_{3}$ ) $_{6}$ is a little small and might pass through the 5.0 m filter in the melt filtration process.

Journal Articles

Influence of nitric acid and plutonium concentrations in dissolver solution of mixed oxide fuel on decontamination factors for uranyl nitrate hexahydrate crystal

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

Radiochimica Acta, 98(6), p.315 - 320, 2010/06

https://doi.org/10.1524/ract.2010.1732

Times Cited Count：7 Percentile：42.21(Chemistry, Inorganic & Nuclear)

In order to examine the decontamination behavior of the Pu and fission products in the U crystallization process, experiments were carried out using mixed oxide fuel dissolver solution. It is confirmed that Eu was decontaminated by washing the uranyl nitrate hexahydrate crystals. However, the decontamination factors of Ba and Cs were low because they precipitated as Ba(NO $_{3}$ ) $_{2}$ and Cs $_{2}$ Pu(NO $_{3}$ ) $_{6}$ after the U crystallization, respectively. The decontamination factor of Cs tends to decrease with increasing HNO $_{3}$ and Pu concentrations in the mother liquor because of the generation of Cs $_{2}$ Pu(NO $_{3}$ ) $_{6}$ .

Journal Articles

Preparation and characterization of dicesium tetravalent plutonium hexanitrate

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

Journal of Alloys and Compounds, 489(2), p.659 - 662, 2010/01

https://doi.org/10.1016/j.jallcom.2009.09.143

Times Cited Count：3 Percentile：18.15(Chemistry, Physical)

Characterization of Cs and Pu(IV) nitrate complex was examined to separation from the UNH crystal. This complex is obtained as a precipitate by mixing dissolver solution of MOX fuel and CsNO $_{3}$ solution, which was identified to dicesium tetravalent plutonium hexanitrate, Cs $_{2}$ Pu(NO $_{3}$ ) $_{6}$ by concentration analysis and XRD. The precipitate has a tendency to be generated at high HNO $_{3}$ condition. Thermal analysis shows that the precipitate is stable below 245 $^{circ}$ C, and a weight loss of about 10.29% is observed at 245 $^{circ}$ C. This result corresponds to the decomposition of Cs $_{2}$ Pu(NO $_{3}$ ) $_{6}$ to Cs $_{2}$ PuO $_{2}$ (NO $_{3}$ ) $_{4}$ . According to these properties, the UNH crystal can be melted at 60 $^{circ}$ C to 100 $^{circ}$ C, and separated from the Pu(IV) and Cs complex by a filtration. A new technology of crystal purification method aimed at higher decontamination of UNH crystal in the U crystallization process is proposed.

Journal Articles

Research and development of crystal purification for product of uranium crystallization process

Yano, Kimihiko; Nakahara, Masaumi; Nakamura, Masahiro; Shibata, Atsuhiro; Nomura, Kazunori; Nakamura, Kazuhito*; Tayama, Toshimitsu; Washiya, Tadahiro; Chikazawa, Takahiro*; Kikuchi, Toshiaki*; et al.

Proceedings of International Conference on Advanced Nuclear Fuel Cycle; Sustainable Options & Industrial Perspectives (Global 2009) (CD-ROM), p.143 - 150, 2009/09

JAEA Reports

None

Koizumi, Masumichi; Honda, Yutaka*; Yumoto, Ryozo; ; ; ; Hirasawa, Masayoshi; Yagi, Takao

PNC TN841 79-38, 250 Pages, 1979/06

Washiya, Tadahiro; Chikazawa, Takahiro*; Nagata, Masanobu*; Kikuchi, Toshiaki*; Hirasawa, Izumi*

no journal, ,

no abstracts in English

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ZMH crystals addition to prevent ZMH encrustation in Mo-Zr-Te HNO $_{3}$ solution

Encrustation prevention of zirconium molybdate hydrate

Purification of uranium products in crystallization system for nuclear fuel reprocessing

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

Influence of nitric acid and plutonium concentrations in dissolver solution of mixed oxide fuel on decontamination factors for uranyl nitrate hexahydrate crystal

Preparation and characterization of dicesium tetravalent plutonium hexanitrate

Research and development of crystal purification for product of uranium crystallization process

None

Investigation of the chemical composition for the Zr-Te deposition by reaction crystallization method

Research and development of crystal purification in crystallization process, 14; Summary of this research program

Research and development on crystal purification in crystallization process, 12; Purification test of crystal in non-radioactive simulated condition

Beam-line improvement and new experiment stations of KEK-IMSS slow-positron facility

Recent developments and results of the KEK slow positron facility

Behavior of grain shape and size of zirconium molybdate hydrate in crystallization reaction

Preventing zirconium molybdate accumulation based on crystallization

Prevention of ZMH adhesion by the addition of MoO $_{3}$ crystal

Preventing encrustation of Zirconium Molybdate Hydrate by suspended molybdenum trioxide hydrate

Crystallization system development for advanced aqueous reprocessing process

Research and development on crystal purification in crystallization process, 6; Summary of development in 2007 JPY

Research and development on crystal purification in crystallization process, 7; Experimental studies on the inclusion behavior of liquid FP simulant in UNH crystals, 2