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Yamagishi, Isao; Ozawa, Masaki; Mimura, Hitoshi*; Kanamura, Shohei*; Mizuguchi, Koji*
Proceedings of 13th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2010) (CD-ROM), p.107 - 116, 2010/10
The present paper describes the progress on Fission Product (FP) separation in the Adv.-ORIENT (Advanced Optimization by Recycling Instructive Elements) cycle. The AMP-SG adsorbent (silica gel loaded with ammonium molybdophosphate) and CE-ALG microcapsule (alginate gel polymer enclosed with crown ether) were developed for separation of heat-generating elements, Cs and Sr, respectively. The AMP-SG adsorbed more than 99% of Cs from a simulated High-level Liquid Waste (HLLW). The CE-ALG adsorbed 0.0249 mmol/g of Sr. An electrodeposition is advantageous for both recovery and utilization of PGMs (Ru, Rh, Pd) and Tc. Pd was easily deposited on a Pt electrode. Reduction of Ru and Tc was accelerated in the presence of Pd or Rh. In the simulated HLLW, the redox reaction of Fe(III)/Fe(II) disturbed deposition of elements except for Pd. The deposit on Pt electrode from the simulated HLLW showed higher catalytic reactivity on electrolytic hydrogen production than that from solution containing only PGM.
Fujita, Reiko*; Nakamura, Hitoshi*; Mizuguchi, Koji*; Utsunomiya, Kazuhiro*; Amamoto, Ippei
Proceedings of 2008 Joint Symposium on Molten Salts (USB Flash Drive), p.886 - 891, 2008/10
Pyrochemical treatment in molten salts is a promising process for decontamination of radioactive wastes without producing large amounts of secondary waste. In this report, the fundamental experiment was carried out to treat the wastes which had complicated shapes such as Magnoxend corps, metallic waste contaminated by uranium, spent chemical trap fillers and spent Zircaloy channel boxs from BWR and acquired good results.
Kofuji, Hirohide; Okamura, Nobuo; Mizuguchi, Koji*; Myochin, Munetaka
Journal of Nuclear Science and Technology, 45(9), p.942 - 950, 2008/09
Times Cited Count：2 Percentile：16.99(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.
MoO
meltMizuguchi, Koji; Yasuike, Yoshiyuki*; Fukushima, Mineo; Myochin, Munetaka
Nihon Genshiryoku Gakkai Wabun Rombunshi, 6(4), p.484 - 490, 2007/12
We develop a new decladding process which integrates with dissolution using the molybdenum oxide melt. This melt possesses characteristics that can make actinide oxide dissolve at high speed without reacting with metal such as the cladding tube. To construct the new process, it is necessary to clarify the reaction mechanisms of uranium in dissolution, oxidation, and electrolysis in this melt. In this study, the gram-scale uranium examination was carried out, and the reaction mechanism of the uranium in the melt was clarified. In NaMoO - NaMoO
melts, uranium dioxide dissolves as NaU(MoO) without changing its oxidation number. In the oxidation, uranium valence was oxidized from IV to VI with oxygen. In electrolysis process, it was clarified that the low current efficiency was caused by the re-dissolution of deposit. The granulated UO was recovered on the cathode by adjusting the temperature of the melt to 700 degrees centigrade at which re-dissolution was reduced.
Hayashi, Hirokazu; Akabori, Mitsuo; Minato, Kazuo; Mizuguchi, Koji*; Kawabe, Akihiro*; Fujita, Reiko*
Denki Kagaku Oyobi Kogyo Butsuri Kagaku, 75(7), p.528 - 534, 2007/07
Times Cited Count：0 Percentile：0.01(Electrochemistry)The simulation code for the pyrochemical processing of spent nuclear fuels was developed to analyze experimental data, to predict experimental results, and to propose adequate conditions and processes. The Simulation code for Pyrochemical Reprocessing (SPR) is based on calculations of chemical equilibrium and electrochemical reactions. The code also includes the calculations of the current-potential distribution between the electrodes. Some calculations were made to simulate the experimental results on the electro-codeposition process of UO
and PuO. The phenomena of the redox reactions between Pu
and Pu
ions and those between Fe and Fe
ions were theoretically analyzed; these redox reactions cause the low current efficiency in the electro-codeposition process. The calculated current-potential distribution around the cathode corresponds to the observed distribution of the oxide deposited on the cathode.
Sato, Fuminori; Mizuguchi, Koji; Nakanishi, Shigeyuki; Myochin, Munetaka
Nihon Genshiryoku Gakkai Wabun Rombunshi, 5(4), p.268 - 281, 2006/12
MOX co-deposition process, which is one of the main parts of oxide electrowinning process, was studied by both sides of examination and analysis. Parameter tests using U and Pu were performed as basic examination, and fundamental data of the process such as polarization property of molten salt including U and Pu, current efficiency of electrolysis and PuO concentration in recovered deposit, etc. were acquired. In addition, to analyze the process behavior, especially polarization property at electrolysis, a reaction model considering Pu, Pu, UO, UO
, PuO and PuOin molten NaCl-2CsCl salt was developed. The validity of this model was confirmed by comparison of the experimental and analytical results. Using this model behavior of chemical species in the process was studied and control factors of MOX co-deposition process were discussed.
Myochin, Munetaka; Mizuguchi, Koji; Kormilitsyn, M. V.*; Ossipenko, A.*
Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 4 Pages, 2005/10
In the Oxide Pyro-process, oxides of U, Np and Pu can be co-deposited as MOX from their oxide ions in the melt. Due to the difference of their deposition potential, neither Am nor Cm will co-deposit in the MOX. An additional process must be developed to recover them without FP especially the lanthanides. Various processes were reviewed based on existing experimental data and thermodynamic considerations. As the result, the liquid metal extraction seems to be most promising. Based on the measured separation factor of Am against Nd in the LiCl-KCl/Bi system, MA recovery rate can be higher than 95% with DF equals 10. The number of steps can be reduced if there is any other liquid metal such as Al and Ga with higher separation factor. As for the carbonate precipitation, some subsequent separation process will be needed. A new process named MAPLE is proposed for it; where Li is applied to reduce only MA oxide into metal in LiCl melt while keeping lanthanides as their oxide. If it works as expected, it will have high recovery rate such as 99% without lowering the DF.
Minato, Kazuo; Hayashi, Hirokazu; Mizuguchi, Koji*; Sato, Takeyuki*; Amano, Osamu*; Miyamoto, Satoshi*
Proceedings of GLOBAL2003 Atoms for Prosperity; Updating Eisenhower's Global Vision for Nuclear Energy (CD-ROM), p.778 - 781, 2003/11
The simulation technology for the pyrochemical reprocessing of oxide fuels was developed to analyze experimental data, to predict experimental results, and to propose adequate conditions and processes. The simulation method was based on calculations of chemical equilibrium and electrochemical reactions. Some model calculations to simulate the experimental results were made on the process of electro-codeposition of UO and PuO. Although it was difficult to trace the experiments and compare the calculated results with the experimental results quantitatively due to the limitation of available data on the experimental conditions, the calculated results were consistent with the experimental results. The phenomena of the repeated oxidation-reduction reactions between Pu and Pu ions and those between Fe and Fe ions were theoretically analyzed,which caused the low current efficiency in the electro-codeposition process.
and NM Elements in Oxide-Electrowinning ReprocessingKosugi, Kazumasa; Fukushima, Mineo; Myochin, Munetaka; Mizuguchi, Koji*; Omori, Takashi*
Proceedings of 11th International IUPAC Conference on High Temperature Materials Chemistry (HTMC-11), 0 Pages, 2003/00
None
; Sato, Fuminori; ; Mizuguchi, Koji*; Omori, Takashi*; Fujita, Reiko*
Nihon Genshiryoku Gakkai Wabun Rombunshi, 1(3), p.312 - 316, 2002/00
None
Ozawa, Masaki; Kawabe, Akihiro*; Mizuguchi, Koji*; Fujita, Reiko*; Sumida, Yukio*
no journal, ,
no abstracts in English
Ozawa, Masaki; Kawabe, Akihiro*; Mizuguchi, Koji*; Fujita, Reiko*; Sumida, Yukio*
no journal, ,
no abstracts in English
Hotokezaka, Hiroyasu*; Ban, Yasutoshi; Ikeda, Hidematsu*; Harada, Masayuki*; Mizuguchi, Koji*; Saso, Michitaka*; Sugai, Hiroshi*; Tokeshi, Manabu*; Ikeda, Yasuhisa*; Morita, Yasuji; et al.
no journal, ,
The following items were studied for developing innovative equipment for analysis that provides high-sensitivity and rapid analysis for ultra small amount of samples utilizing microchip and thermal lens detector: Optimum flow condition for forming two-phase steady laminar flow in micro channel, applicability of thermal lens detector for U(VI) and H concentration analysis, extraction properties of U(VI) from aqueous phase to organic phase in micro channel, and radiation resistance of microchips and capillary tubes. In this presentation the summary of these items are reported.
Mizuguchi, Koji; Fukushima, Mineo; Yasuike, Yoshiyuki*
no journal, ,
no abstracts in English
Sato, Fuminori; Mizuguchi, Koji
no journal, ,
no abstracts in English
Fukushima, Mineo; Mizuguchi, Koji; Myochin, Munetaka; Yasuike, Yoshiyuki*; Arai, Tsuyoshi*
no journal, ,
no abstracts in English
Kofuji, Hirohide; Mizuguchi, Koji; Myochin, Munetaka
no journal, ,
no abstracts in English
Hayashi, Hirokazu; Akabori, Mitsuo; Minato, Kazuo; Mizuguchi, Koji*; Kawabe, Akihiro*; Fujita, Reiko*
no journal, ,
The simulation code for the pyrochemical processing of spent nuclear fuels was developed to analyze experimental data, to predict experimental results, and to propose adequate conditions and processes. The Simulation code for Pyrochemical Reprocessing (SPR) is based on calculations of chemical equilibrium and electrochemical reactions. The code also includes the calculations of the current-potential distribution between the electrodes. Some calculations were made to simulate the experimental results on the electro-codeposition process of UO and PuO. The phenomena of the redox reactions between Pu and Pu ions and those between Fe and Fe ions were theoretically analyzed; these redox reactions cause the low current efficiency in the electro-codeposition process. The calculated current-potential distribution around the cathode corresponds to the observed distribution of the oxide deposited on the cathode.
Mizuguchi, Koji; Yasuike, Yoshiyuki*; Fukushima, Mineo; Myochin, Munetaka
no journal, ,
no abstracts in English
Fukushima, Mineo; Myochin, Munetaka; Mizuguchi, Koji*
no journal, ,
no abstracts in English
