Characteristics of TPDN/SiO-P adsorbent for MA(III) recovery

Kofuji, Hirohide; Watanabe, So; Takeuchi, Masayuki; Suzuki, Hideya; Matsumura, Tatsuro; Shiwaku, Hideaki; Yaita, Tsuyoshi

Progress in Nuclear Science and Technology (Internet), 5, p.61 - 65, 2018/11

https://doi.org/10.15669/pnst.5.61

CFD analysis for U extraction in a centrifugal contactor

Sano, Yuichi; Sakamoto, Atsushi; Kofuji, Hirohide; Takeuchi, Masayuki

Proceedings of 21st Pacific Basin Nuclear Conference (PBNC 2018) (USB Flash Drive), p.314 - 318, 2018/09

The effect of operational condition of the annular centrifugal contactor (ACC) on U extraction behavior was investigated by computational fluid dynamics (CFD) analysis considering mass transfer between aqueous and organic phases, and the calculation results were validated experimentally. The CFD analysis with ANSYS FLUENT was carried out using the Eulerian multi-fluid approach with a standard k- turbulence model. In order to calculate the droplet size of the dispersed phase and mass transfer between aqueous and organic phases, user-defined functions (UDF) were created. The changes of U extraction performance, i.e. U stage efficiency, with the rotor speed and the O/A ratio (= organic flowrate / aqueous flowrate) were calculated, and these showed a good agreement with experimental results.

Micro-PIXE analysis on adsorbent of extraction chromatography for MA(III) recovery

Takahatake, Yoko; Watanabe, So; Kofuji, Hirohide; Takeuchi, Masayuki; Nomura, Kazunori; Sato, Takahiro*

International Journal of PIXE, 26(3&4), p.73 - 83, 2017/09

BB2016-1248.pdf:0.36MB

https://doi.org/10.1142/S0129083517500012

JAEA has been conducting research and development of MA(III) recovery from HLLW by extraction chromatography technology for reduction in amount and environmental impact of radioactive waste. The behavior of adsorbed cations inside the adsorbent packed in a column is necessary to be evaluated for improvement of the adsorbent or flow-sheet to achieve targeted MA(III) recovery performance. In this paper, micro-PIXE analysis was carried out on the particles sampled from various positions of the column to reveal the behavior of cations inside the packed column with CMPO/SiO -P adsorbent. Simple experiment and data analysis were shown to be effective to reveal inside of the column, and formation and transportation of the adsorption bands were observed for some cations which are extractable by the CMPO extractant. Some part of Zr(IV) and Mo(VI) were found to remain inside the column without distinct transportation even after the elution operation.

Granulation study of porous silica particles for MA recovery process

Goto, Ichiro; Kofuji, Hirohide; Oriuchi, Akio; Watanabe, So; Takeuchi, Masayuki

Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 6 Pages, 2017/04

JAEA has been working on partition of minor actinides from high-level liquid wastes (HLLW) generated in the reprocessing by extraction chromatography technology. This technology utilizes 50 micro m porous silica particles coated by styrene-divinylbenzene copolymer in which an extractant for MA recovery is impregnated as adsorbent. Adsorption/elution performance of the adsorbent depends on sizes of the particle and pore of the particle. In this study, spray drying granulating experiments with various operating conditions and with different experimental apparatuses were carried out to find an appropriate condition to control the sizes of the particle and the pore.

Irradiation degradation of adsorbents for minor actinides recovery

Watanabe, So; Sano, Yuichi; Kofuji, Hirohide; Takeuchi, Masayuki; Koizumi, Tsutomu

NEA/NSC/R(2015)2 (Internet), p.338 - 344, 2015/06

https://www.oecd-nea.org/science/docs/2015/nsc-r2015-2.pdf

Optimization of chemical composition in the iron phosphate glass as the matrix of high level waste generated from pyroprocessing

Kofuji, Hirohide; Yano, Tetsuji*; Myochin, Munetaka; Matsuyama, Kanae*; Okita, Takeshi*; Miyamoto, Shinya*

Proceedings of 22nd International Conference on Nuclear Engineering (ICONE-22) (DVD-ROM), 6 Pages, 2014/07

https://doi.org/10.1115/ICONE22-30688

For the research and development of the nuclear waste disposal concept suitable to the pyrochemical processing system and its performance evaluation, the iron-phosphate glass is examined as an alternative waste form for high level waste generated from electro-refining process. In order to enhance the waste element content in the glass matrix and improve the durability of the waste form, optimization experiments of the glass composition were carried out and the effect of additional other transition metal oxides was found out in this study.

Precipitation behaviors of fission products by phosphate conversion in LiCl-KCl medium

Amamoto, Ippei; Kofuji, Hirohide; Myochin, Munetaka; Takasaki, Yasushi*; Yano, Tetsuji*; Terai, Takayuki*

Nuclear Technology, 171(3), p.316 - 324, 2010/09

https://doi.org/10.13182/NT10-A10867

The separation technique by phosphate conversion of FP from NaCl-KCl or NaCl-2CsCl as the medium of the spent electrolyte of pyroprocessing is being developed at RIAR in Russia. To ascertain the technical feasibility of applying this RIAR's method for recycling of spent electrolyte which composed of FP such as AL, ALE, and REE and 3LiCl-2KCl as the medium, preliminary study was undertaken at JAEA. This study occupies an auxiliary role which is forwarded as a part of FaCT Project of Japan. As a first approach, the thermodynamic analysis to understand the behaviours of FP in the electrolyte was carried out after literature research and acquisition of required thermodynamic properties. Preliminary experiment was then undertaken to observe the conversion behaviours of chlorides to phosphate. In this paper, these results are shown and are evaluated to discern the feasibility of the phosphate conversion method.

Separation of lanthanoid phoshates from the spent electrolyte of pyroprocessing

Amamoto, Ippei; Kofuji, Hirohide; Myochin, Munetaka; Tsuzuki, Tatsuya*; Takasaki, Yasushi*; Yano, Tetsuji*; Terai, Takayuki*

Proceedings of 12th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM '09/DECOM '09) (CD-ROM), 9 Pages, 2009/10

https://doi.org/10.1115/ICEM2009-16265

This study is carried out to make the pyroprocessing hold a competitive advantage. As one of the measures is to reduce the volume of HLW, the phosphate conversion method is applied for removal of FP from the spent electrolyte in this paper. Though the removing target elements in the electrolyte are alkali metals, alkaline earth metals and lanthanoid elements, only lanthanoid elements and lithium form the insoluble phosphates by reaction with LiPO. Therefore, as the first step, the precipitation experiment was carried out to observe the behaviours of elements which form the insoluble precipitates. Then the filtration was experimented to remove precipitates in the spent electrolyte using FeO-PO glass system as a filtlation medium which is compatible material with the glassification. The result of separation of precipitates by filtration was effective and attained almost 100.

Phosphates behaviours in conversion of FP chlorides

Amamoto, Ippei; Kofuji, Hirohide; Myochin, Munetaka; Takasaki, Yasushi*; Terai, Takayuki*

Journal of Nuclear Materials, 389(1), p.142 - 148, 2009/05

https://doi.org/10.1016/j.jnucmat.2009.01.019

The spent electrolyte of the pyroprocessing by metal electrorefining method should be considered for recycling after removal of FP, such as AL (alkali metals), ALE (alkaline earth metals), and/or REE (rare-earth elements), to reduce the volume of HLW. Authors have been carrying out theoretical analysis and experiment showing the behaviours of phosphate precipitates so as to estimate the feasibility of the phosphate conversion method. From hitherto results, it was found that AL except Li, and ALE are unlikely formed phosphate precipitates. However, their conversion behaviours including REE were compatible with former presented theoretical analysis; in the case of lanthanum precipitate as one of REE, submicron-size particles could be observed while that of LiPO was larger; under different conversion temperatures, the precipitates were apt to grow larger at higher temperature; etc..

Effect of pulse electrolysis on morphology of co-deposited MOX granules

Kofuji, Hirohide; Okamura, Nobuo; Mizuguchi, Koji*; Myochin, Munetaka

Journal of Nuclear Science and Technology, 45(9), p.942 - 950, 2008/09

https://doi.org/10.3327/jnst.45.942

In the oxide electrowinning method of nuclear fuel recycling, the applicability of the pulse electrolysis method to the MOX co-deposition process was evaluated. Several experiments were conducted involving uranium, plutonium, and elements simulating fission product (FP) or corrosion product (CP). Through study of the results of these experiments, the influences of the impurities and the effect of the waveform of electrolysis pulses on the electro-deposit were clarified. As a result, pulse electrolysis conditions which could restrain Pu enrichment of the deposited MOX were confirmed. Furthermore, it was found that the element distribution in the MOX granule obtained by the pulse electrolysis was homogenized, which is well suited for nuclear fuel fabrication. Finally, a qualitative model of the pulse electrolysis reaction near the field of cathode surface is proposed.