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Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.
Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03
Times Cited Count：44 Percentile：97.1(Astronomy & Astrophysics)Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 
C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.
Koyama, Shinichi; Suzuki, Tatsuya*; Ozawa, Masaki*; Kurosawa, Kiyoko*; Fujita, Reiko*; Mimura, Hitoshi*; Okada, Ken*; Morita, Yasuji; Fujii, Yasuhiko*
Procedia Chemistry, 7, p.222 - 230, 2012/00
Times Cited Count：2 Percentile：70.98(Chemistry, Analytical)Adv.-ORIENT cycle strategy has been proposed as a basic concept for trinitarian research on separation, transmutation and utilization of nuclides and elements based on FBR fuel cycle. Validation of principal separation method and related safety research were performed from 2006 through 2011 as Phase I program. First, more than 90% of Cs could be recovered from the actual spent fuel [IXC(I) step]. The next is the adsorption of the platinum group metals (PGM), lanthanides, Am and Cm were separated by using a tertiary pyridine-type resin (TPR) as ion exchange steps [IXC(II, III, IV) steps]. The separated PGM metals will be supplied to the electrochemical extraction [CEE step]. As experiment for safety issues, Hastelloy-B at RT and Ta at 90C were confirmed their anti-corrosive in highly concentrated HCl media. Thermo-chemical stability for TPR was verified. Issues to be solved for next phase based on the final results of phase I program.
Koyama, Shinichi; Yamagishi, Isao; Suzuki, Tatsuya*; Ozawa, Masaki*; Fujita, Reiko*; Okada, Ken*; Tatenuma, Katsuyoshi*; Mimura, Hitoshi*; Fujii, Yasuhiko
Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 8 Pages, 2011/12
Effective separation of MA and LLFP, transmutation and utilization were the main directions of Advanced OREINT Cycle project. Study for each integrant technology was concluded as first trial of the project. TPR enabled to separate MA/Ln and then Am/Cm precisely from spent fuel in HCl and HNO
media. CEE method could separate the light PGM and Tc by HCl media. Recovery of Cs from simulated HLLW coul be achieved more than 90 %. In addition, the perspective for next phase was proposed.
Suzuki, Tatsuya*; Nomura, Masao*; Fujii, Yasuhiko*; Ikeda, Atsushi; Takaoka, Toru*; Oguma, Koichi*
Nihon Ion Kokan Gakkai-Shi, 21(3), p.328 - 333, 2010/09
Zinc isotope fractionation in an anion exchange resin has been investigated in hydrochloric acid solution by chromatographic technique. It was found that the heavier zinc isotopes were located disproportionately in the solution phase. The isotope fractionation coefficient was varied from the order of 10
to 10
depending on the hydrochloric acid concentration. The maximum isotope fractionation coefficient was obtained in 1 
hydrochloric acid, while the distribution coefficient of zinc became maximum at around 2 hydrochloric acid. This difference has been further discussed based on the calculated speciation and structural information derived from X-ray absorption spectroscopy.
Ozawa, Masaki; Suzuki, Tatsuya*; Koyama, Shinichi; Yamagishi, Isao; Fujita, Reiko*; Okada, Ken*; Tatenuma, Katsuyoshi*; Mimura, Hitoshi*; Fujii, Yasuhiko*
Proceedings of International Conference on Advanced Nuclear Fuel Cycle; Sustainable Options & Industrial Perspectives (Global 2009) (CD-ROM), p.1117 - 1126, 2009/09
Hasegawa, Makoto; Nakanishi, Takashi*; Fujii, Yasuhiko*; Odaka, Tomohiro*
Hosha Kagaku Nyusu, (17), p.29 - 35, 2008/03
no abstracts in English
Ozawa, Masaki; Suzuki, Tatsuya*; Koyama, Shinichi; Akatsuka, Hiroshi*; Mimura, Hitoshi*; Fujii, Yasuhiko*
Progress in Nuclear Energy, 50(2-6), p.476 - 482, 2008/03
Times Cited Count：38 Percentile：90.4(Nuclear Science & Technology)For the minimization of the ecological burden originated in nuclear fuel recycling, a new R&D strategy was filed as "Adv.-ORIENT cycle". In the context, mutual precise separation of 
-elements, such as minor actinide (MA)/lanthanides (Lns) and Am/Cm, are highly essential for enhancing the MA (
Am) burning. The separation and utilization of rare metal fission products (RMFPs; Ru, Tc, etc) are a new direction in the partitioning and transmutation field. Separation of exothermic nuclides, 
Sr, 
Cs as well as MA, will significantly help to improve the repository tasks. A key separation media are ion exchange chromatography (IXC) by tertiary pyridine resin and a catalytic electrolytic extraction (CEE) by Pd
. On challenging the isotope separation of LLFP, theoretical and laboratory studies were begun for 
Cs, 
Sn in the first priority.
Yamamura, Osamu; Yamamoto, Ryuichi; Nomura, Shigeo; Fujii, Yasuhiko*
Progress in Nuclear Energy, 50(2-6), p.666 - 673, 2008/03
Times Cited Count：4 Percentile：29.44(Nuclear Science & Technology)The application of safeguards to the Tokai Reprocessing Plant(TRP), the world's first reprocessing plant with a sole objective of commercial use, was made on try and error basis because it was the first experience for both the plant and the inspection sides. Through thirty years' faithful cooperation to the IAEA-initiated safeguards program, TRP contributed also to the developments of the international credibility upon the concept of safeguards system of Reprocessing plant in non-nuclear weapon countries. TRP also has been processing over 1,123 ton of spent fuels from the beginning of its active operation in Sept.'77. For 30 years operation of TRP, many technological problems have been overcome to obtain the stable and reliable operation. The process for establishments of maintenance technology in TRP was evaluated through the analysis of significant plant equipment failures reported to the Government and so on. Discussion in this paper is also emphasized that the safeguards system and the maintenance technologies developed by TRP have been applied to the first Rokkasho commercial reprocessing plant (RRP). Furthermore, this operation knowledge base can contribute to the design and construction of the next generation reprocessing plant.
Koyama, Shinichi; Ozawa, Masaki; Okada, Ken*; Kurosawa, Kiyoko*; Suzuki, Tatsuya*; Fujii, Yasuhiko*
Proceedings of International Conference on Advanced Nuclear Fuel Cycles and Systems (Global 2007) (CD-ROM), p.1530 - 1536, 2007/09
Simplified separation process was proposed based on ion-exchange technique. HCl, HNO and MeOH were used as an eluent. To develop an engineering scale concept, it is indispensable to establish the condition for safety operation. Corrosion test of structural materials in the HCl was performed by using some metals. In this experiment, it was proved that the Ta, Zr, Nb and hastelloy have good endurance to HCl solution. Research of thermal hazard of pyridine-type ion-exchange resin, MeOH and HNO media system was studied in the view point of fire and explosion safety. There is no hazardous reaction between IER/MeOH, HNO media system. In the case of more than 150C, we should pay attention to the exothermic reaction at dried condition NO-IER or IER/HNO media system.
Ozawa, Masaki; Koyama, Shinichi; Suzuki, Tatsuya*; Fujita, Reiko*; Mimura, Hitoshi*; Fujii, Yasuhiko*
Proceedings of International Conference on Advanced Nuclear Fuel Cycles and Systems (Global 2007) (CD-ROM), p.451 - 457, 2007/09
To minimize the ecological burden originating in nuclear fuel recycling, a new R&D strategy, Adv.-ORIENT (Advanced Optimization by Recycling Instructive ElemeNTs) cycle, was set forth. A key separation tool is ion exchange chromatography (IXC) by a tertiary pyridine resin having soft donor nitrogen atoms. This method has provided individual recovery of pure Am and Cm products with a Pu/U/Np fraction from irradiated fuel in just a 3-step separation. A catalytic electrolytic extraction (CEE) method by Pd has been employed to separate, purify and fabricate RMFP catalysts. High separation efficiency of RMFP proved hydrochloric acid as a suitable media for their recovery. Different functioned ion exchangers, e.g., ammonium molybdophosphate (AMP), have been investigated for the separation of Cs
. Theoretical and laboratory studies on the isotope separation of LLFPs were begun for 
Se, Sn and Cs.
Ozawa, Masaki; Fujita, Reiko*; Koyama, Shinichi; Suzuki, Tatsuya*; Fujii, Yasuhiko*
Proceedings of 9th OECD/NEA Information Exchange Meeting on Actinide and Fission Product Partitioning and Transmutation, p.315 - 324, 2007/00
Catalytic Electrolytic extraction method has been studied as a separation tool for rare metal fission products, RMFP in the spent nuclear fuel. In an employed CEE process, Pd
cation itself would not only be easily deposited from various nitric acid solutions, but enhance also the deposition of co-existing RuNO
, ReO
and 
TcO by acting as a catalyst. The quaternary-, Pd-Ru-Rh-Re, deposit Pt or Ti electrode, fabricated by CEE, suggested the highest cathodic current corresponding to the hydrogen generation reaction in both alkaline solution and sea water. Advanced ORIENT Cycle, where ion exchange chromatography using tertiary pyridine resin and the CEE employ as mainstay separation technology, will enhance separation and utilization of actinide and fission product, and thus be expected to realize ultimate reducing radioactive wastes.
Ozawa, Masaki; Koyama, Shinichi; Suzuki, Tatsuya*; Fujii, Yasuhiko*
Czechoslovak Journal of Physics, 56(Suppl.D), p.D579 - D587, 2006/12
Radiochemical separation experiments have been performed in order to realize a novel reprocessing method based on ion-exchange technique. The newly synthesized soft-donor type tertiary pyridine resin was dedicated to the experiments, where highly irradiated mixed oxide fuel from the experimental fast reactor JOYO was used as a reference spent fuel. With a 3 step separation, pure Am and Cm were individually obtained as MA products, and 
Ru group, Lns with Cs (HLLW group) and Pu group were fractionated, respectively. The decontamination factor of Cs and trivalent lanthanides (
Eu, 
Ce) in the Am product exceeded 39,000 and 100,000, respectively. The decontamination factor for the mutual separation of 
Cm and Am was larger than 2200 for the Am product. Moreover, the content of Cs, trivalent lanthanides and Cm in Am product did not exceed 2 ppm. The tertiary pyridine resin method suggests a reality as a candidate separation system for an "advanced ORIENT process", where total separation, transmutation and utilization of An, LLFP and rare metal fission product (RMFP) were oriented.
Koyama, Shinichi; Ozawa, Masaki; Suzuki, Tatsuya*; Fujii, Yasuhiko*
Journal of Nuclear Science and Technology, 43(6), p.681 - 689, 2006/06
Multi-functional spent fuel reprocessing process was established based on ion-exchange method under collaboration between Japan Nuclear Cycle Development Institute (JNC) and Tokyo Institute of Technology (TITEC). The tertiary pyridine-type anion exchange resin developed by TITEC was used in this experiment. The separation process was designed in hot laboratory of JNC and demonstrated by applying highly irradiated MOX fuel. As the results of experiment, we could effectively separate to some element groups. According to the results, the separation process consisting of 3 steps was proposed as follows; (1) Platinum group element separation as a pre-filtration step (STEP-I), (2) Sequential separation step of trivalent lanthanides, trivalent actinides and plutonium as for fuel matrix (STEP-II), (3) Mutual separation step of americium and curium (STEP-III)In these processes, general reagents were only used and the resin could be recycled, in addition to be salt-free CHON compounds. And we can cope with the problem of secondary waste from a new reprocessing process.
Ozawa, Masaki; Koyama, Shinichi; Suzuki, Tatsuya*; Fujii, Yasuhiko*
Journal of Nuclear and Radiochemical Sciences, 6(3), p.275 - 278, 2005/12
None
Ozawa, Masaki; Suzuki, Tatsuya*; Fujii, Yasuhiko*
Proceedings of 10th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM '05) (CD-ROM), 6 Pages, 2005/09
None
Ozawa, Masaki; Suzuki, Tatsuya*; Koyama, Shinichi; Fujii, Yasuhiko*
Dai-1-Kai COE-INES Kokusai Shimpojiumu, (12), 25 Pages, 2004/00
Japan Nuclear Cycle Development Institute (JNC) developed the remote monitoring system (RMS) for NDA data with Los Alamos National Laboratory (LANL) under the JNC/DOE agreement on cooperation of safeguards. The purpose of this development is to improve the efficiency of safeguards activities for both the operator and the inspector. To achieve this purpose, JNC and LANL initiated RMS hardware and software and performed field trial by using Plutonium Canister Assay System (PCAS), which is unattended NDA system installed in the feed storage at Plutonium Fuel Production Facility (PFPF). The development of the RMS for NDA data has been already completed and this system will be implemented for inspection use through the final operational tests by 2004.JNC plans to expand the developed RMS into the entire facility by integration it with other unattended NDA systems and containment and surveillance (C/S) systems at PFPF. By this expansion, impact on facility operation will be vastly reduced under the comprehensive safeguards agreement. Furthermore, the remote monitoring technology will contribute to establishment of the integrated safeguards approach, which is the new safeguards approach to improve efficiency of safeguards, as one of the important technologies.This paper shows the future plan of the RMS at PFPF and its expected effect.
*; Akatsuka, Hiroshi*; *; Suzuki, Tatsuya*; *; *;
JNC TY9400 2000-009, 41 Pages, 2000/03
JNC-TY9400-2000-009.pdf:1.22MB
no abstracts in English
; Kiuchi, Kiyoshi; *; *; *
Fusion Engineering and Design, 39-40, p.923 - 928, 1998/00
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)no abstracts in English
; Kiuchi, Kiyoshi; *; *; *
Journal of Nuclear Materials, 258-263, p.1066 - 1072, 1998/00
Times Cited Count：0 Percentile：0.01(Materials Science, Multidisciplinary)no abstracts in English
Fujie, Makoto; *; *; *
Journal of Nuclear Science and Technology, 23(4), p.330 - 337, 1986/00
Times Cited Count：46 Percentile：96.4(Nuclear Science & Technology)no abstracts in English
