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Takemura, Fumiaki*; Taba, Ryo*; Hirayama, Keita*; Tansuriyavong, S.*; Kawabata, Kuniaki; Sagara, Shinichi*; Ogasawara, Kei*
Artificial Life and Robotics, 22(4), p.405 - 411, 2017/12
The manta method is a survey method that divers investigate the degree of coral and whitening state while being towed to a boat. The manta method makes great physical burden. Therefore, the authors think that this task can substitute an underwater robot. This underwater robot is desirable to be able to keep altitude above the seabed. Hence, the authors have been developing the altitude (its distance above the sea floor) keeping system for an underwater robot. Visual recognition of distant underwater objects is possible in the water with high transparency, for example, in the coastal sea area of Okinawa prefecture, Japan. So, the authors have been adopting the distance measuring method using the two laser beams and a monocular camera with image processing. It realize to keep altitude of an underwater robot by using such devices. The evaluation experiments of the altitude keeping system are carried out in the pool.
Mori, Masanobu*; Sagara, Katsuya*; Arai, Kaori*; Nakatani, Nobutake*; Ohira, Shinichi*; Toda, Kei*; Itabashi, Hideyuki*; Kozaki, Daisuke*; Sugo, Yumi; Watanabe, Shigeki; et al.
Journal of Chromatography A, 1431, p.131 - 137, 2016/01
Times Cited Count：10 Percentile：41.49(Biochemical Research Methods)Taba, Ryo*; Takemura, Fumiaki*; Tansuriyavong, S.*; Kawabata, Kuniaki; Sagara, Shinichi*; Ogasawara, Kei*
Proceedings of 21st International Symposium on Artificial Life and Robotics (AROB 21st 2016) and 1st International Symposium on BioComplexity (ISBC-1) (Internet), p.395 - 399, 2016/01
Nakashima, Yosuke*; Takeda, Hisahito*; Ichimura, Kazuya*; Hosoi, Katsuhiro*; Oki, Kensuke*; Sakamoto, Mizuki*; Hirata, Mafumi*; Ichimura, Makoto*; Ikezoe, Ryuya*; Imai, Tsuyoshi*; et al.
Journal of Nuclear Materials, 463, p.537 - 540, 2015/08
Times Cited Count：20 Percentile：83.66(Materials Science, Multidisciplinary)Nakashima, Yosuke*; Sakamoto, Mizuki*; Yoshikawa, Masayuki*; Oki, Kensuke*; Takeda, Hisahito*; Ichimura, Kazuya*; Hosoi, Katsuhiro*; Hirata, Mafumi*; Ichimura, Makoto*; Ikezoe, Ryuya*; et al.
Proceedings of 25th IAEA Fusion Energy Conference (FEC 2014) (CD-ROM), 8 Pages, 2014/10
Am content on homogenization of denatured Pu with broad range of neutron energy based on U irradiation test in the experimental fast reactor JoyoShiba, Tomooki*; Sagara, Hiroshi*; Onishi, Takashi; Koyama, Shinichi; Maeda, Shigetaka; Han, C. Y.*; Saito, Masaki*
Annals of Nuclear Energy, 51, p.74 - 80, 2013/01
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)The design consideration of DU-Am oxide fuel pin was performed for Pu denaturing in the framework of the protected plutonium production based on the irradiation analyses of the depleted U (DU) samples irradiated in the environment of broad range of neutron energy in the experimental fast reactor Joyo. From the results of irradiation analyses of DU, it was confirmed that there is a strong dependence of transmutation behavior of DU on the resonance neutron ratio even in a fast reactor. Also, it was confirmed that there is a strong effect of sample material form and shape on generated Pu nuclide inventory especially near the reflector area (
20% resonance neutron ratio), because of the intensive self-shielding of 
U, though less is expected for Am. Sensitivity study of hypothetical DU-Am oxide fuel pellet irradiation on neutron energy and burn-up was performed to evaluate significant gradient of radial Pu isotopic composition profile (e.g., from 12 to 18% distribution in 3% Am doping, in 30% resonance neutron ratio and in 4.0
10
[n/cm
] of neutron fluence inside a large pellet with softened neutron spectrum), and vulnerability of the fuel pellet surface in terms of Pu denaturing was revealed. Design consideration of radial zoning of Am content was introduced to flatten the radial distribution of isotopic composition of Pu. The results of radial zoning of Am (4% and 3% of Am in the outer and inner zone of DU-Am oxide fuel pellet) in hypothetical irradiation neutronics analysis showed the radial profile of produced Pu is over 15 at.% of Pu isotopic composition in any zone and meets the criteria of Kimura et al. based on decay heat of Pu to impede utilization to fission explosive devices.
Onishi, Takashi; Koyama, Shinichi; Shiba, Tomooki*; Sagara, Hiroshi*; Saito, Masaki*
Progress in Nuclear Energy, 57, p.125 - 129, 2012/05
Times Cited Count：1 Percentile：10.1(Nuclear Science & Technology)In order to develop blanket fuel with high proliferation resistance in fast breeder reactor, chemical analysis of nine U samples irradiated in experimental fast reactor Joyo and Pu contents and Pu isotopic composition of the samples were measured. As results, dependence of Pu production behavior from U on neutron spectra was revealed.
Koyama, Shinichi; Osaka, Masahiko; Ito, Masahiko*; Sagara, Hiroshi*; Saito, Masaki*
Journal of Nuclear Science and Technology, 47(8), p.661 - 670, 2010/08
Times Cited Count：6 Percentile：40.12(Nuclear Science & Technology)A project on Protected Plutonium Production (P
) was proposed by Tokyo Institute of Technology as part of a non-proliferation research program for plutonium (Pu) utilization in nuclear reactors. A determination of Pu isotopes in 
Np samples irradiated in the experimental fast reactor JOYO was done to evaluate Pu production from Np under fast neutron spectra. In the mean time, 2, 5 and 10% Np-containing U samples were irradiated in the Advanced Test Reactor at the Idaho National Laboratory (INL) to evaluate Pu production in the thermal neutron region. The verified transmutation data can be used to design fuel pellets for non-proliferation.
Koyama, Shinichi; Osaka, Masahiko; Ito, Masahiko*; Sagara, Hiroshi*; Saito, Masaki*
Proceedings of International Conference on Advanced Nuclear Fuel Cycle; Sustainable Options & Industrial Perspectives (Global 2009) (CD-ROM), p.2356 - 2362, 2009/09
A project of Protected Plutonium Production was proposed by Tokyo-Tech as a part of non-proliferation research for Pu utilization to nuclear reactor. In order to validate this concept, two irradiation tests were performed. Experimental determination of Pu isotopes in Np samples irradiated in the experimental fast reactor JOYO was done to evaluate Pu production from Np under the fast neutron spectra. On the other hand, 2%, 5% and 10% Np containing U samples were also irradiated in Advanced Thermal Reactor of INL to evaluate the Pu production under thermal neutron region. The verified Np transmutation data can be used to design an Np-U mixed oxide fuel pellet for next phase Np-U fuel performance evaluations.
Kikuchi, Mitsuru; Tamai, Hiroshi; Matsukawa, Makoto; Fujita, Takaaki; Takase, Yuichi*; Sakurai, Shinji; Kizu, Kaname; Tsuchiya, Katsuhiko; Kurita, Genichi; Morioka, Atsuhiko; et al.
Nuclear Fusion, 46(3), p.S29 - S38, 2006/03
Times Cited Count：13 Percentile：41.68(Physics, Fluids & Plasmas)The National Centralized Tokamak (NCT) facility program is a domestic research program for advanced tokamak research to succeed JT-60U incorporating Japanese university accomplishments. The mission of NCT is to establish high beta steady-state operation for DEMO and to contribute to ITER. The machine flexibility and mobility is pursued in aspect ratio and shape controllability, feedback control of resistive wall modes, wide current and pressure profile control capability for the demonstration of the high-b steady state.
Tsuchiya, Katsuhiko; Akiba, Masato; Azechi, Hiroshi*; Fujii, Tsuneyuki; Fujita, Takaaki; Fujiwara, Masami*; Hamamatsu, Kiyotaka; Hashizume, Hidetoshi*; Hayashi, Nobuhiko; Horiike, Hiroshi*; et al.
Fusion Engineering and Design, 81(8-14), p.1599 - 1605, 2006/02
Times Cited Count：1 Percentile：9.94(Nuclear Science & Technology)no abstracts in English
plasma operationTamai, Hiroshi; Akiba, Masato; Azechi, Hiroshi*; Fujita, Takaaki; Hamamatsu, Kiyotaka; Hashizume, Hidetoshi*; Hayashi, Nobuhiko; Horiike, Hiroshi*; Hosogane, Nobuyuki; Ichimura, Makoto*; et al.
Nuclear Fusion, 45(12), p.1676 - 1683, 2005/12
Times Cited Count：15 Percentile：45.44(Physics, Fluids & Plasmas)Design studies are shown on the National Centralized Tokamak facility. The machine design is carried out to investigate the capability for the flexibility in aspect ratio and shape controllability for the demonstration of the high-beta steady state operation with nation-wide collaboration, in parallel with ITER towards DEMO. Two designs are proposed and assessed with respect to the physics requirements such as confinement, stability, current drive, divertor, and energetic particle confinement. The operation range in the aspect ratio and the plasma shape is widely enhanced in consistent with the sufficient divertor pumping. Evaluations of the plasma performance towards the determination of machine design are presented.
Kimura, Atsushi; Koizumi, Mitsuo; Toh, Yosuke; Oshima, Masumi; Mizumoto, Motoharu; Goto, Jun*; Arai, Yasuo*; Sagara, Masahiro*; Iri, Shinichi*; Kobayashi, Hirotsugu*; et al.
no journal, ,
To measure neutron cross-section data of minor actinides, we construct a Ge-spectrometer utilizing multiple 
-ray detection method. This spectrometer consists of 30 Ge crystals (40 detector outputs) and 128 BGO anti-Compton shields. Generally, a data acquisition system for such a big Ge spectrometer consists of many NIM modules; it requires large space and huge cost. To overcome these problems, we developed a new data acquisition system with digital signal processing techniques. We reported the conceptual design (and cost) in NSS 2004. In this NSS 2005, we report basic performance of this system (energy resolution, dead time and so on) and results of experiments with the Ge-spectrometer. We measured the energy resolution with a Eurisys clover detector, which is one component of the Ge-spectrometer. Obtained FWHMs (2.5 - 2.8 keV at 1.33 MeV) show good performances as normal MCA even with short shaping time and much higher channel density. The dead time of this system is only 3.2 micro sec per event.
Sudo, Mitsuo; Koyama, Shinichi; Obayashi, Hiroshi; Meiliza, Y.*; Sagara, Hiroshi*; Saito, Masaki*
no journal, ,
Transmutation behavior of plutonium in uranium sample irradiated in experimental fast reactor Joyo was evaluated based on radiochemical analysis in order to develop a blanket fuel with high proliferatin resistance for fast breeder reactor.
Koyama, Shinichi; Sagara, Hiroshi*
no journal, ,
Americium and Uranium samples irradiated in experimental fast reactor Joyo are analyzed to develop a blanket fuel with high proliferation resistance for fast breeder reactor. Based on this results, the conceptual design of americium-containing uranium fuel loated at blanket region in fast breeder reactor is performed, and then proliferatin resistance of produced plutonium at blanket region are evaluated for optimization.
Koyama, Shinichi; Kitamura, Ryoichi; Ito, Masahiko*; Sagara, Hiroshi*; Saito, Masaki*
no journal, ,
In order to experimentally demonstrate for production of Pu having high proliferation resistance, irradiation test of U-Np samples in Advanced Test Reactor of Idaho National Laboratory and the post-irradiation examination of U-Np sample has been conducted.
Onishi, Takashi; Sudo, Mitsuo; Obayashi, Hiroshi; Koyama, Shinichi; Tanaka, Kenya; Meiliza, Y.*; Yamamoto, Tetsuro*; Sagara, Hiroshi*; Saito, Masaki*
no journal, ,
no abstracts in English
Yamamoto, Tetsuro*; Sagara, Hiroshi*; Saito, Masaki*; Koyama, Shinichi; Onishi, Takashi; Okawachi, Yasushi
no journal, ,
no abstracts in English
Onishi, Takashi; Sudo, Mitsuo; Koyama, Shinichi; Tanaka, Kenya; Sekioka, Ken*; Shiba, Tomooki*; Sagara, Hiroshi*; Saito, Masaki*
no journal, ,
In order to develop the high proliferation resistance fuel for fast breeder reactor, plutonium production/incineration behavior of americium samples irradiated in fast reactor "JOYO" was evaluated.
Shiba, Tomooki*; Sagara, Hiroshi*; Saito, Masaki*; Koyama, Shinichi; Maeda, Shigetaka
no journal, ,
In order to design for FBR blanket fuel with high proliferation resistance, transmutation behavior of Am-containing depleted uranium under fast neutron environment is evaluated by computer simulation as a parameter of the Am content. Produced plutonium having high proliferation resistance are reduced with decreasing neutron energy in the case of Joyo irradiation condition.
