Aoyagi, Noboru; Palladino, G.*; Nagasaki, Shinya*; Kimura, Takaumi
Bulletin of the Chemical Society of Japan, 91(6), p.882 - 890, 2018/06
The speciation and coordination geometries of M(III)-citrate complexes in aqueous solutions, where M denotes Eu, Tb, Lu, or Cm, are studied using potentiometric titration, nuclear magnetic resonance spectroscopies. Their photophysical properties are also characterized by time-resolved fluorescence spectra. The formation constants of mononuclear, dinuclear, and trinuclear Lu-citrate species were determined by potentiometric titration in 3.00 M NaClO aqueous media. Terminal carboxylic conformation in trinuclear complexes comprised both the five- and six-membered rings at different exchanging rates. Hydration states evaluated for Eu ions are the chemical formula of [Eu(Cit) (H O) ] and [Eu(OH)(Cit)(HO)]. These complexes in aqueous solution have geometrical similarity to the crystal structures in the literature. Furthermore, the entity of the hetero-trinuclear complex induces the intramolecular energy transfer from Tb to Eu. The incorporation of Cm into these homo/hetero-trinuclear citrate complexes proved to be a successful trial to probe the formation of actinide polymer at a trace level.
Nakayama, Shinichi; Okumura, Masahiko*; Nagasaki, Shinya*; Enokida, Yoichi*; Umeki, Hiroyuki*; Takase, Hiroyasu*; Kawasaki, Daisuke*; Hasegawa, Shuichi*; Furuta, Kazuo*
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 23(2), p.131 - 148, 2016/12
A symposium "Science of nuclear fuel cycle and backend - Research and education -" was held at the Univer-sity of Tokyo in June 25, 2016. This aimed at developing the research on nuclear fuel cycle and backend. The time and the number of participants of the symposium were limited, but the active discussion was conducted, and the common perception for the future was shared among the experienced participants in those fields. This paper provides the discussions made in the symposium, and also, as a memory to Professor Ahn, the University of California, Berkeley, his prominent achievements in academic research and education.
Nagasaki, Shinya*; Saito, Takumi; Yang, T.*
Journal of Radioanalytical and Nuclear Chemistry, 308(1), p.143 - 153, 2016/04
Sorption of Np(V) on illite, shale and MX-80 under oxidizing conditions were first studied in two types of high ionic strength solutions: (1) a reference brine solution (SR-270-PW) with an ionic strength (I) of 6.0 M, and (2) Na-Ca-Cl solutions (with different Na/Ca molar ratios and different ionic strengths, up to a maximum of 4.6 M). The effects of pHc, Na/Ca ratio, and ionic strength on sorption in Na-Ca-Cl solutions were investigated. The Kd values increased with increasing pHc and Na/Ca ratio for all sorbents studied. The Kd values on illite and shale were independent of the ionic strength over the range 0.10-4.6 M, and the Kd value on MX-80 was independent of ionic strength greater than 1.0 M. The Kd values and the sorption isotherms in both SR-270-PW and Na-Ca-Cl solutions were also studied.
Aoyagi, Noboru; Toraishi, Takashi*; Nagasaki, Shinya*; Tanaka, Satoru*
Journal of Applied Solution Chemistry and Modeling, 1(2), p.148 - 155, 2012/12
Lukman, S.*; Saito, Takumi*; Aoyagi, Noboru; Kimura, Takaumi; Nagasaki, Shinya*
Geochimica et Cosmochimica Acta, 88, p.199 - 215, 2012/07
Ishida, Keisuke*; Saito, Takumi*; Aoyagi, Noboru; Kimura, Takaumi; Nagaishi, Ryuji; Nagasaki, Shinya*; Tanaka, Satoru*
Journal of Colloid and Interface Science, 374(1), p.258 - 266, 2012/05
Hirano, Fumio; Sato, Seichi*; Kozaki, Tamotsu*; Inagaki, Yaohiro*; Iwasaki, Tomohiko*; Oe, Toshiaki*; Kato, Kazuyuki*; Kitayama, Kazumi*; Nagasaki, Shinya*; Niibori, Yuichi*
Journal of Nuclear Science and Technology, 49(3), p.310 - 319, 2012/03
The thermal impacts of hull and end piece wastes from the reprocessing of MOX spent fuels burned in LWRs on repository performance were investigated. The heat generation rates in MOX spent fuels and the resulting heat generation rates in hull and end piece wastes change depending on the fuel histories including the burn-up of UO spent fuels, the cooling period before reprocessing, the storage period of fresh MOX fuels. The heat generation rates of hull and end piece wastes from the reprocessing of MOX spent fuels with any of those histories are significantly larger than those from UO spent fuels with burn-ups of 45 GWd/THM. If a temperature below 80C is specified for cement-based materials used in waste packages after disposal, the allowable number of canisters containing compacted hull and end pieces in a package for 45 GWd-MOX needs to be limited to a value of 0.7 to 1.6, which is significantly lower than the value of 4.0 for 45 GWd-UO.
Minato, Kazuo; Konashi, Kenji*; Yamana, Hajimu*; Yamanaka, Shinsuke*; Nagasaki, Shinya*; Ikeda, Yasuhisa*; Sato, Seichi*; Arita, Yuji*; Idemitsu, Kazuya*; Koyama, Tadafumi*
Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 5 Pages, 2011/12
Actinide science research is indispensable to maintain sustainable development of innovative nuclear technology. For actinide science research, special facilities with containment and radiation shields are needed to handle actinide materials. The number of facilities for actinide science research has been decreased, especially in universities, due to the high maintenance cost. J-ACTINET was established in 2008 to promote and facilitate actinide science research and to foster many of young scientists and engineers in actinide science. The research program was carried out, through which young researchers were expected to learn how to make experiments with advanced experimental tools and to broaden their horizons. The summer schools and computational science school were held to provide students and young researchers with the opportunities to come into contact with actinide science research. The overseas dispatch program was also carried out.
Nakayama, Shinichi; Okoshi, Minoru; Shimada, Taro; Tachibana, Mitsuo; Momma, Toshiyuki; Niibori, Yuichi*; Nagasaki, Shinya*; Ahn, J.*
Genshiryoku Kyokasho "Hoshasei Haikibutsu No Kogaku", 235 Pages, 2011/01
This book is designed to provide everyone with an interest in radioactive waste issues, including students and individuals involved in engineering and public administration, with a graduate-level understanding of radioactive wastes from the scientific foundations that support radioactive waste management covering radioactive waste generation including decommissioning of nuclear facilities, treatment, disposal, clearance and their safety assessment. This book is the one volume of the English translation of the text series "An Advanced Course in Nuclear Engineering" lectured in the University of Tokyo.
Saito, Takumi*; Sao, Hirokazu*; Ishida, Keisuke*; Aoyagi, Noboru; Kimura, Takaumi; Nagasaki, Shinya*; Tanaka, Satoru*
Environmental Science & Technology, 44(13), p.5055 - 5060, 2010/07
Minato, Kazuo; Konashi, Kenji*; Fujii, Toshiyuki*; Uehara, Akihiro*; Nagasaki, Shinya*; Otori, Norikazu*; Tokunaga, Yo; Kambe, Shinsaku
IOP Conference Series; Materials Science and Engineering, 9, p.012018_1 - 012018_7, 2010/05
Basic research in actinide chemistry and physics is indispensable to maintain sustainable development of innovative nuclear technology. Actinides, especially minor actinides of americium and curium, need to be handled in special facilities with containment and radiation shields. To promote and facilitate the actinide research, close cooperation with the facilities and sharing of technical and scientific information must be very important and effective. A three-year-program "Basic actinide chemistry and physics research in close cooperation with hot laboratories", ACTILAB, was started to form the bases of sustainable development of innovative nuclear technology. In this program, researches on actinide solid-state physics, solution chemistry and solid-liquid interface chemistry are made using four main facilities in Japan in close cooperation with each other, where basic experiments with transuranium elements can be made. The O-NMR measurements were performed on (PuAm)O to study the electronic state and the chemical behaviour of Am and Cm ions in electrolyte solutions was studied by distribution experiments.
Nagasaki, Takanori*; Shiotani, Shinya*; Igawa, Naoki; Yoshino, Masahito*; Iwasaki, Kota*; Fukazawa, Hiroshi; Utsumi, Wataru
Journal of Solid State Chemistry, 182(10), p.2632 - 2639, 2009/10
We propose a new method, a difference maximum entropy method (MEM) analysis of the neutron diffraction data, for revealing the detailed structure around hydrogen atoms in proton-conducting oxides. This MEM analysis uses the differences between the structure factors of protium- and deuterium-dissolved crystals. Simulations demonstrate that it not only provides the distribution of hydrogen atoms alone, but also improves the spatial resolution of MEM mapping around hydrogen atoms. Applied to actual diffraction data of protium- and deuterium-dissolved BaSnInO at 9 K, difference MEM analysis reveals that O-D bonds mostly tilt towards the second nearest oxygen atoms, and that the distributions of deuterium and oxygen atoms are probably insignificant in interstitial regions.
Nagasaki, Takanori*; Ito, Tsuyoshi*; Yoshino, Masahito*; Iwasaki, Kota*; Shiotani, Shinya*; Fukazawa, Hiroshi; Igawa, Naoki; Ishii, Yoshinobu*
Journal of Nuclear Science and Technology, 45(Suppl.6), p.122 - 127, 2008/09
The neutron powder diffraction measurement was carried out at 10 K on the proton-conducting oxide BaZrInO with and without dissolved DO. Obtained diffraction data were analyzed by the Rietveld method and the maximum entropy method. It was found that deuterium atoms were located close the 12 site of the cubic perovskite structure with the space group -.
Isayama, Akihiko; Suzuki, Takahiro; Hayashi, Nobuhiko; Ide, Shunsuke; Hamamatsu, Kiyotaka; Fujita, Takaaki; Hosoyama, Hiroki; Kamada, Yutaka; Nagasaki, Kazunobu*; Oyama, Naoyuki; et al.
AIP Conference Proceedings 933, p.229 - 236, 2007/10
no abstracts in English
Takenaka, Yoko*; Saito, Takumi*; Nagasaki, Shinya*; Tanaka, Satoru*; Kozai, Naofumi; Onuki, Toshihiko
Geomicrobiology Journal, 24(3-4), p.205 - 210, 2007/09
no abstracts in English
Kurosawa, Susumu; Nagasaki, Shinya*; Tanaka, Satoru*
Nihon Genshiryoku Gakkai Wabun Rombunshi, 6(2), p.205 - 213, 2007/06
no abstracts in English
Nakayama, Shinichi; Nagasaki, Shinya*; Inagaki, Yaohiro*; Oe, Toshiaki*; Sasaki, Takayuki*; Sato, Seichi*; Sato, Tsutomu*; Tanaka, Satoru*; Tochiyama, Osamu*; Nagao, Seiya*; et al.
JAEA-Conf 2007-003, 120 Pages, 2007/03
The 1st information exchange meeting on Radioactive Waste Disposal Research Network was held in Nuclear Science Research Institute of Japan Atomic Energy Agency on August 4, 2006. Radioactive Waste Disposal Research Network was established by under Interorganization Atomic Energy Research Program of Japan Atomic Energy Agency, and the objective is to bring both research infrastructures and human expertise in Japan to an adequate performance level, thereby contributing to the development of the fundamental research area in the field of radioactive waste disposal. This lecture material is a collection of research presentations and discussions during the information exchange meeting.
JNC TJ8400 2003-064, 106 Pages, 2004/03
We explained how the metal binding to heterogeneous surfaces can be modeled and showed the modeling results of the copper binding to humic acid by the NICA-Donnan model. This report concentrates on two topic: (i) the modeling of the copper binding to goethite, one of representative metal (hydr)oxides, by the CD-MUSIC model and (ii) the influence of the adsorption of humic acid on goethite upon the proton binding to their mixture. The recent progress in the modeling of the ternary system (metal ions/ NOMs/ OXs) is also introduced at the end of the report.
Tanaka, Satoru*; Nagasaki, Shinya*; Nakata, Kotaro*; Oda, Takuji*; Kameda, Jun*; Kamei, Gento; Tachi, Yukio
JNC TY8400 2003-008, 88 Pages, 2003/05
Redox reactions between Cr(VI) and iron(II) chloride (FeCl2) and those between Cr(VI) and magnetite (Fe(II)1Fe(III)2O4) were observed as a preliminary study. According to the experimental results, it was suggested that the redox reactions were promoted more than the amount of Fe(II) on magnetite surface because of electron transfer from internal Fe(II) to magnetite surface. The results were quantitatively supported from quantum chemical calculations. Redox reactions between Np(V) and magnetite and the reduction of Np to tetravalent were observed, while those between Np(V) and FeCl2 were not observed obviously. It was observed that the reactions were promoted rapidly when the magnetite / solution ratio and the temperature were high, and the rate constant of the reactions was obtained. Furthermore, it was found that hydrogen gas and hydrogen ion were generated with crushing the quartz in an inert gas atmosphere.
JNC TJ8400 2002-058, 186 Pages, 2003/03
Model V and NICA-Donnan model, which can describe the interaction of humic acids with metals, were reviewed and CD-MUSIC model, which is a typical surface complexation model of metals with solid surfaces, was also introduced. In Model V, the equilibrium of chemicals among water in environment, sediments and solids is considered. In NICA-Donnan model, the electrostatic interactions due to the difference in the activities between humic acids and bulk is included and the heterogeneity of binding sites in humic acids is also taken into account. In this report, the problems of these models was summarized and the future development was discussed. In experimental part, the proton dissociation reaction and the interaction with Cu were investigated, by titration experiments using Aldrich humic acids. Considering NICA-Donnan model, the interaction parameters of the proton dissociation reaction and the interaction with Cu were evaluated. In calculation part, the mixing characteristics of water flow in fracture junctions was discussed by Real-coded Lattice Gas model. The mixing ratio at the outlet of fracture junctions was analyzed qualitatively and quantitatively as a function of Peclet number. Furthermore, the trajectory of colloid transport in the laminar flow at bending tube was calculated, and the effect of the mass of colloid was qualitatively studied. The random walk and diffusion phenomena of colloids were found to be successfully calculated by Real-coded Lattice Gas model developed in this work.