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-P adsorbent for MA(III) recoveryKofuji, 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
Watanabe, So; Suzuki, Hideya; Goto, Ichiro*; Kofuji, Hirohide; Matsumura, Tatsuro
Nihon Ion Kokan Gakkai-Shi, 29(3), p.71 - 75, 2018/09
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.
Watanabe, So; Sano, Yuichi; Kofuji, Hirohide; Takeuchi, Masayuki; Shibata, Atsuhiro; Nomura, Kazunori
Journal of Radioanalytical and Nuclear Chemistry, 316(3), p.1113 - 1117, 2018/06
Times Cited Count：7 Percentile：65.53(Chemistry, Analytical)Takahatake, Yoko; Watanabe, So; Kofuji, Hirohide; Takeuchi, Masayuki; Nomura, Kazunori; Sato, Takahiro*
International Journal of PIXE, 26(3&4), p.73 - 83, 2017/09
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.
Takeuchi, Masayuki; Sano, Yuichi; Watanabe, So; Nakahara, Masaumi; Aihara, Haruka; Kofuji, Hirohide; Koizumi, Tsutomu; Mizuno, Tomoyasu
Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 6 Pages, 2017/04
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.
Watanabe, So; Nomura, Kazunori; Kitawaki, Shinichi; Shibata, Atsuhiro; Kofuji, Hirohide; Sano, Yuichi; Takeuchi, Masayuki
Procedia Chemistry, 21, p.101 - 108, 2016/12
Times Cited Count：9 Percentile：98.51
/UO
couple in LiMoO
-NaMoO eutectic melt at 550
CNagai, Takayuki; Uehara, Akihiro*; Fujii, Toshiyuki*; Sato, Nobuaki*; Kofuji, Hirohide; Myochin, Munetaka; Yamana, Hajimu*
Journal of Nuclear Materials, 454(1-3), p.159 - 163, 2014/11
Times Cited Count：0 Percentile：0.01(Materials Science, Multidisciplinary)The redox equilibrium of UO/UO couple was measured in LiMoO-NaMoO eutectic melt at 550C by cyclic voltammetry and absorption spectrophotometry. The standard redox potential of UO/UO couple was approximately evaluated by cyclic voltammetry. Further, the absorption spectrum and equilibrium potential were measured, repeatedly adding UO source material into the melt containing UO. From the correlation between the equilibrium potential of the melt and the concentration ratio [UO]/[UO] spectrophotometrically evaluated, the standard redox potential of UO/UO couple was determined to be -0.847
0.010 V vs. O/O
.
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
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.
Kofuji, Hirohide; Yano, Tetsuji*; Myochin, Munetaka; Matsuyama, Kanae*; Okita, Takeshi*; Miyamoto, Shinya*
Procedia Chemistry, 7, p.764 - 771, 2012/00
Times Cited Count：12 Percentile：95.58As a part of the research and development for the nuclear waste disposal concept suitable to the advanced fuel cycle systems and its performance evaluation, the iron-phosphate glass is examined as an alternative waste form for high level waste generated from pyrochemical reprocessing. In order to enhance the waste element content in the glass matrix and improve the durability of the waste form, optimization experiments of glass composition were carried out and the effect of additional other transition metal oxides was found out in this study.
Amamoto, Ippei; Kofuji, Hirohide; Myochin, Munetaka; Takasaki, Yasushi*; Yano, Tetsuji*; Terai, Takayuki*
Nuclear Technology, 171(3), p.316 - 324, 2010/09
Times Cited Count：11 Percentile：61.1(Nuclear Science & Technology)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.
Kofuji, Hirohide; Fukushima, Mineo; Kitawaki, Shinichi; Myochin, Munetaka; Kormilitsyn, M. V.*; Terai, Takayuki*
IOP Conference Series; Materials Science and Engineering, 9, p.012010_1 - 012010_8, 2010/05
Times Cited Count：0 Percentile：1.02Amamoto, 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
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 Li
PO. 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
.
Kofuji, Hirohide; Amamoto, Ippei; Sasaki, Kazuya*; Yasumoto, Masaru*; Takasaki, Yasushi*; Myochin, Munetaka; Terai, Takayuki*
Denki Kagaku Oyobi Kogyo Butsuri Kagaku, 77(8), p.597 - 600, 2009/08
Times Cited Count：0 Percentile：0.01(Electrochemistry)The process flow of the phosphate conversion technique has been developed for the reduction of high-level radioactive waste (HLW) generated from the metal-electrorefining process. In this study, the results of thermodynamic calculations for the phosphate conversion reactions were examined by the basic experiments. The chlorides of rare earth elements (REE) turned out to be converted into phosphates easily. Furthermore, as the additive for the phosphate conversion reaction, high temperature behavior of lithium phosphate was evaluated to elucidate the thermodynamic property.
Amamoto, Ippei; Kofuji, Hirohide; Myochin, Munetaka; Takasaki, Yasushi*; Terai, Takayuki*
Journal of Nuclear Materials, 389(1), p.142 - 148, 2009/05
Times Cited Count：14 Percentile：68.52(Materials Science, Multidisciplinary)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..
Kofuji, Hirohide; Amamoto, Ippei; Yasumoto, Masaru*; Sasaki, Kazuya*; Myochin, Munetaka; Terai, Takayuki*
Journal of Nuclear Materials, 389(1), p.173 - 178, 2009/05
Times Cited Count：4 Percentile：31.69(Materials Science, Multidisciplinary)Adaptation of the phosphate conversion technique was undertaken and evaluated for application to the recycle process of the spent electrolyte generated from metal electrorefining process which is a kind of pyrochemical reprocessing technologies. The conceptual flow sheet has been discussed based on the thermodynamic properties of constituent. However few data have been published relating to the phosphate, therefore, the thermodynamic data were attempted to be obtained by the calorimetry and vapor pressure measurements. The measurements have been started with pure substance such as lithium phosphate. Through the measurements of HTMS and TG-DTA, it was clarified that decomposition or phase transition of LiPO occurred at specific temperatures below the melting point of LiPO. To avoid the influence of fragment substances which have high vapour pressures, improved method of the HTMS measurement was examined.
Kofuji, Hirohide; Okamura, Nobuo; Mizuguchi, Koji*; Myochin, Munetaka
Journal of Nuclear Science and Technology, 45(9), p.942 - 950, 2008/09
Times Cited Count：1 Percentile：10.5(Nuclear Science & Technology)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.
Amamoto, Ippei; Kofuji, Hirohide; Myochin, Munetaka; Terai, Takayuki*
Shimyureshon, 27(3), p.189 - 197, 2008/09
Some specific FPs are apt to remain in the medium (electrolyte) used in pyroprocessing even after recovery of uranium and transuranic elements. It is desirable to have the spent electrolyte purified for recycling which in turn, could lead to the reduction of HLW. This study is carried out to evaluate the feasibility of the electrolyte recycle process by the phosphates conversion technique. The evaluation was undertaken mainly by thermodynamic simulation which was especially highlighted the conversion effect at the Spent Electrolyte Generation Step. The obtained computational value and a conceptual idea for recovery of precipitates by this simulation were then reflected to establish the preliminary conceptual flow diagram which would facilitate the next discussion and experiment for the realization of this process.
Amamoto, Ippei; Kofuji, Hirohide; Myochin, Munetaka; Terai, Takayuki*
Proceedings of International Conference on Advanced Nuclear Fuel Cycles and Systems (Global 2007) (CD-ROM), p.748 - 757, 2007/09
FP such as alkali metals, alkaline earth metals and rare-earth elements are apt to remain in the eutectic medium used in pyroreprocessing even after treatment at the pyrocontactor step. It is desirable to have the spent electrolyte purified for recycling which in turn, could lead to the reduction of HLW. This study is carried out to evaluate the feasibility of the electrolyte recycling process by the phosphate conversion technique. First of all, a reference block flow diagram, which consists of three steps, was designed based on known developmental results from literature. Subsequently, evaluation was undertaken by comparison with conventional relevant experimental and theoretical analysis results after gathering the essential basic data for thermodynamic calculation. The obtained computational value was then reflected to establish the preliminary conceptual flow diagram which would facilitate the next discussion and experiment for the realization of this process.
