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Arai, Yoichi; Watanabe, So; Hasegawa, Kenta; Okamura, Nobuo; Watanabe, Masayuki; Takeda, Keisuke*; Fukumoto, Hiroki*; Ago, Tomohiro*; Hagura, Naoto*; Tsukahara, Takehiko*
Nuclear Instruments and Methods in Physics Research B, 542, p.206 - 213, 2023/09
Times Cited Count：0 Percentile：0.02(Instruments & Instrumentation)Nakajima, Kenji; Kawakita, Yukinobu; Ito, Shinichi*; Abe, Jun*; Aizawa, Kazuya; Aoki, Hiroyuki; Endo, Hitoshi*; Fujita, Masaki*; Funakoshi, Kenichi*; Gong, W.*; et al.
Quantum Beam Science (Internet), 1(3), p.9_1 - 9_59, 2017/12
The neutron instruments suite, installed at the spallation neutron source of the Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC), is reviewed. MLF has 23 neutron beam ports and 21 instruments are in operation for user programs or are under commissioning. A unique and challenging instrumental suite in MLF has been realized via combination of a high-performance neutron source, optimized for neutron scattering, and unique instruments using cutting-edge technologies. All instruments are/will serve in world-leading investigations in a broad range of fields, from fundamental physics to industrial applications. In this review, overviews, characteristic features, and typical applications of the individual instruments are mentioned.
Kunimaru, Takanori; Mikake, Shinichiro; Nishio, Kazuhisa; Tsuruta, Tadahiko; Matsuoka, Toshiyuki; Ishibashi, Masayuki; Ueno, Takashi; Tokuyasu, Shingo; Daimaru, Shuji; Takeuchi, Ryuji; et al.
JAEA-Review 2012-020, 178 Pages, 2012/06
JAEA-Review-2012-020.pdf:33.16MB
Japan Atomic Energy Agency (JAEA) at Tono Geoscience Center (TGC) is pursuing a geoscientific research and development project namely the Mizunami Underground Research Laboratory (MIU) Project in crystalline rock environment in order to construct scientific and technological basis for geological disposal of High-level Radioactive Waste (HLW). The MIU Project has three overlapping phases: Surface-based Investigation phase (Phase I), Construction phase (Phase II), and Operation phase (Phase III). The MIU Project has been ongoing the Phase II. And Phase III started in 2010 fiscal year. This report shows the results of the investigation, construction and collaboration studies in fiscal year 2010, as a part of the Phase II based on the MIU Master Plan updated in 2002.
Kuramitsu, Yasuhiro*; Nakanii, Nobuhiko*; Kondo, Kiminori; Sakawa, Yoichi*; Mori, Yoshitaka*; Miura, Eisuke*; Tsuji, Kazuki*; Kimura, Kazuya*; Fukumochi, Shuji*; Kashihara, Mamoru*; et al.
Physical Review E, 83(2), p.026401_1 - 026401_6, 2011/02
Times Cited Count：16 Percentile：65.74(Physics, Fluids & Plasmas)An energy distribution function of energetic particles in the universe or cosmic rays is well represented by a power-law spectrum, therefore, nonthermal acceleration is essential to understand the origin of cosmic rays. A possible candidate for the origin of cosmic rays is wakefield acceleration at relativistic astrophysical perpendicular shocks. Substituting an intensive laser pulse for the large amplitude light waves, we performed a model experiment of the shock environments in a laboratory plasma.
Kuramitsu, Yasuhiro*; Nakanii, Nobuhiko*; Kondo, Kiminori; Sakawa, Yoichi*; Mori, Yoshitaka*; Miura, Eisuke*; Tsuji, Kazuki*; Kimura, Kazuya*; Fukumochi, Shuji*; Kashihara, Mamoru*; et al.
Physics of Plasmas, 18(1), p.010701_1 - 010701_4, 2011/01
Times Cited Count：19 Percentile：62.41(Physics, Fluids & Plasmas)Substituting an intensive laser pulse for the large amplitude light waves, we performed a model experiment of the shock environments in a laboratory plasma. An intensive laser pulse was propagated in a plasma tube created by imploding a hollow polystyrene cylinder, as the large amplitude light waves propagated in the upstream plasma at an astrophysical shock. Nonthermal electrons were generated, and the energy distribution functions of the electrons have a power-law component with an index of 2.
Hamamoto, Shimpei; Sakaba, Nariaki; Takeda, Yoichi*
Nihon Genshiryoku Gakkai Wabun Rombunshi, 9(2), p.174 - 182, 2010/09
Chemistry control is important for the helium coolant of High Temperature Gas-cooled Reactors (HTGRs). Decarburizing atmosphere reduced creep rupture strength of the heat resistant alloy using for the heat exchanger. This paper describes active control of impurities concentration using existing helium purification system which consists of helium heater, Cupper oxide bed (CuOT), Molecular sieve bed, Cold Charcoal bed and each bypass line. Analysis showed that efficiency control of CuOT is effective in an improvement of decarburizing atmosphere. This effect is based on that H
which is not removed cause the increase in carbon monoxide effective in formation of carburizing atmosphere by water-gas-shift reaction.
Pb
Sr
CuO
Hiraka, Haruhiro*; Hayashi, Yoichiro*; Wakimoto, Shuichi; Takeda, Masayasu; Kakurai, Kazuhisa; Adachi, Tadashi*; Koike, Yoji*; Yamada, Ikuya*; Miyazaki, Masanori*; Hiraishi, Masatoshi*; et al.
Physical Review B, 81(14), p.144501_1 - 144501_6, 2010/04
Times Cited Count：15 Percentile：55.02(Materials Science, Multidisciplinary)Sakaba, Nariaki; Hamamoto, Shimpei; Takeda, Yoichi*
Journal of Nuclear Science and Technology, 47(3), p.269 - 277, 2010/03
Times Cited Count：7 Percentile：45.04(Nuclear Science & Technology)Lifetime extension of high-temperature equipment such as the intermediate heat exchanger of high-temperature gas-cooled reactors (HTGRs) is important from the economical point of view. Since the replacing cost will cause the increasing of the running cost, it is important to reduce replacing times of the high-cost primary equipment during assumed reactor lifetime. In the past, helium chemistry has been controlled by the passive chemistry control technology in which chemical impurity in the coolant helium is removed as low concentration as possible, as does Japan's HTTR. Although the lifetime of high-temperature equipment almost depends upon the chemistry conditions in the coolant helium, it is necessary to establish an active chemistry control technology to maintain adequate chemical conditions. In this study, carbon deposition which could occur at the surface of the heat transfer tubes of the intermediate heat exchanger and decarburization of the high-temperature material of Hastelloy XR used at the heat transfer tubes were evaluated by referring the actual chemistry data obtained by the HTTR. The chemical equilibrium study contributed to clarify the algorism of the chemistry behaviours to be controlled. The created algorism is planned to be added to the instrumentation system of the helium purification systems. In addition, the chemical composition to be maintained during the reactor operation was proposed by evaluating not only core graphite oxidation but also carbon deposition and decarburization. It was identified when the chemical composition could not keep adequately, injection of 10 ppm carbon monoxide could effectively control the chemical composition to the designated stable area where the high-temperature materials could keep their structural integrity beyond the assumed duration. The proposed active chemistry control technology is expected to contribute economically to the purification systems of the future very high-temperature reactors.
Yamamoto, Masahiro*; Honda, Yosuke*; Miyajima, Tsukasa*; Uchiyama, Takashi*; Kobayashi, Masanori*; Muto, Toshiya*; Matsuba, Shunya*; Sakanaka, Shogo*; Sato, Kotaro*; Saito, Yoshio*; et al.
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.860 - 862, 2009/08
A newly 500 kV electron gun (2nd - 500 kV gun) for an ERL light source is designed at KEK. A new concept and state of-the-art technologies of vacuum system, ceramic insulators, high voltage power supply, photocathode and preparation system will be employed. The details are described in this report.
Sakaba, Nariaki; Hamamoto, Shimpei; Takeda, Yoichi*
Proceedings of 4th International Topical Meeting on High Temperature Reactor Technology (HTR 2008) (CD-ROM), 7 Pages, 2008/09
Lifetime extension of high-temperature materials utilized, for instance, at the heat transfer tubes of the intermediate heat exchanger of high-temperature gas-cooled reactors is important because high-cost primary equipment will be continued its operation during reactor lifetime without replacing. Since lifetime of high-temperature materials almost depends upon the chemistry conditions in the coolant helium, it is necessary to establish an active chemistry control methods. This technology can maintain adequate chemical conditions during reactor operation. In the past, helium chemistry has been controlled by the passive chemistry control technology in which chemical impurity in the coolant helium removes as low concentration as possible, as does Japan's first high-temperature gas-cooled reactor HTTR. In this study, carbon deposition which could be occurred at the surface of the heat transfer tube and decarburization of the high-temperature material of Hastelloy XR were evaluated by referring the chemistry data obtained by the HTTR. In addition, the chemical composition to be maintained during the reactor operation in order to keep the structural integrity and thermal efficiency of the heat transfer tube was proposed by evaluating not only core graphite oxidation, but also carbon deposition and decarburization. It was also identified when the chemical composition could not keep adequately, injection of 10 ppm carbon monoxide could effectively control the chemical composition to the designated stable area where the high-temperature materials can keep their structural integrity beyond the assumed duration. The proposed active chemistry control technology is expected to contribute economically to the purification systems of the future very high-temperature reactors.
Sakaba, Nariaki; Hamamoto, Shimpei; Takeda, Yoichi*
Transactions of the American Nuclear Society, 97(1), p.678 - 680, 2007/11
Inherent safety advantages of the helium gas cooled reactors over other types of reactors depend importantly on the chemical stability of the actual helium coolant gas itself. Although helium being an inert gas does not react with fuel and components, chemical impurities which exist in the actual helium coolant can react with the surface of high-temperature materials such as the heat transfer tubes of the intermediate heat exchanger. The chemical effect of the impurities strongly influences to shorten the lifetime of the high-temperature materials. The dominant chemical reactions occurring in the core have not previously identified due to the complicated effects of not only high temperatures but also radioactivity during power operation of the helium gas cooled reactors. As such the methodology to control the high-temperature material lifetime has not been established because of the lack of knowledge and active control of the carbon activity and partial pressure of the oxygen which determine the creep fatigue of the high-temperature materials. The present study of the chemical equilibriums in the HTGR core is an initial effort to establish the lifetime extension methodology. The study examines the effects of high temperature and irradiation on the chemical equilibriums in the core by using an analytical code and basing on the chemical impurity data obtained in the HTTR operations.
Takeda, Yoichi*; Hamamoto, Shimpei; Sakaba, Nariaki
Transactions of the American Nuclear Society, 97(1), P. 677, 2007/11
Ni-base heat-resistant alloys are used for the structural components in gas cooled reactors and exposed to high-temperature helium gas environment. The degradation issues of the material like oxidation and creep are primary concern for the plant operation and further development of the alloys to be used in Very High-Temperature Reactor (VHTR) and Gas-Cooled Fast Reactor (GFR). In this investigation, corrosion testing facility was fabricated in order to investigate oxidation behavior of heat resistant alloys in high-temperature helium environments.
Nishitani, Tomohiro; Hajima, Ryoichi; Iijima, Hokuto; Nagai, Ryoji; Sawamura, Masaru; Kikuzawa, Nobuhiro; Nishimori, Nobuyuki; Minehara, Eisuke; Tabuchi, Masao*; Noritake, Yosuke*; et al.
Proceedings of 28th International Free Electron Laser Conference (FEL 2006) (CD-ROM), p.319 - 322, 2006/08
ERL light source and FEL require an electron beam of large current and small emittance. In order to realize an electron gun satisfying such requirements,we started developments of a photocathode DC-gun and a new-type NEA-photocathode. The DC-gun consists of a chamber to activate NEA-surface, a 250 keV acceleration chamber, and a mode-locked Ti:Sapphire laser. Since extreme high vacuum is essential to obtain a long-life photocathode, we adopt a load-lock system for transporting a photocathode between the chambers, each of which is equipped with an NEG pump. Up to now, we fabricated an electrodes chamber and a high voltage terminal of 250 kV and we succeeded in a 250kV high voltage test. We also have suggested a superlattice photocathode as a new-type photocathode with higher performance than an existing technology. Up to now, we fabricated photocathode samples by molecular beam epitaxy and measured a quantum efficiency after NEA-surface activation.
Nishitani, Tomohiro; Tabuchi, Masao*; Noritake, Yosuke*; Hayashitani, Haruhiko*; Hajima, Ryoichi; Iijima, Hokuto; Nagai, Ryoji; Sawamura, Masaru; Kikuzawa, Nobuhiro; Nishimori, Nobuyuki; et al.
Proceedings of 3rd Annual Meeting of Particle Accelerator Society of Japan and 31st Linear Accelerator Meeting in Japan (CD-ROM), p.45 - 47, 2006/00
no abstracts in English
Seko, Noriaki; Katakai, Akio; Hasegawa, Shin; Tamada, Masao; Kasai, Noboru; Takeda, Hayato*; Sugo, Takanobu; Saito, Kyoichi*
Nuclear Technology, 144(2), p.274 - 278, 2003/11
Times Cited Count：127 Percentile：98.72(Nuclear Science & Technology)The total amount of uranium dissolved in seawater at a uniform concentration of 3 mg-U/m
in the world's oceans is 4.5 billion tons. An adsorption method using polymeric adsorbents capable of specifically recovering uranium from seawater is reported to be economically feasible. A uranium-specific non-woven fabric was used as the adsorbent packed in an adsorption cage. We submerged adsorption cages, 16 m
in cross-sectional area and 16 cm in height, in the Pacific Ocean at a depth of 20 m at 7 km offshore of Japan. The cage consisted of stacks of 52,000 sheets of the uranium-specific non-woven fabric with a total mass of 350 kg. The total amount of uranium recovered by the non-woven fabric was more than one kg in terms of yellow cake during a total submersion time of 240 days in the ocean.
Nakahira, Masataka; Takeda, Nobukazu; Takahashi, Hiroyuki*; Yagenchi, Akira*; Akutsu, Yoichi; Tada, Eisuke; Yabana, Shuichi*
Proceedings of 7th International Conference on Nuclear Engineering (ICONE-7) (CD-ROM), 10 Pages, 1999/00
no abstracts in English
Tsunematsu, Toshihide; Namba, Haruyuki*; Akutsu, Yoichi; Okawa, Yoshinao; Yagenji, Akira; Takeda, Masatoshi*; Yajima, Kensaku*; Nitta, Yoshio*; Kobayashi, Kenichi*; Maeda, Ikuo*; et al.
Fusion Engineering and Design, 41(1-4), p.415 - 420, 1998/09
Times Cited Count：3 Percentile：31.85(Nuclear Science & Technology)no abstracts in English
Hasegawa, Kazuo; Mizumoto, Motoharu; Kusano, Joichi; Tomisawa, Tetsuo; Ouchi, Nobuo; Oguri, Hidetomo; Kinsho, Michikazu; Touchi, Y.*; Honda, Yoichiro*; Akaoka, Nobuo*; et al.
Proceedings of 23rd Linear Accelerator Meeting in Japan, p.19 - 21, 1998/00
no abstracts in English
Takeda, M.*; Okawa, Yoshinao; *; Akutsu, Yoichi; *
Seismic,Shock,and Vibration Isolation 1995 (PVP-Vol. 319), 0, p.317 - 322, 1995/00
no abstracts in English
Takeda, M.*; Okawa, Yoshinao; Akutsu, Yoichi; Suzuki, Hideyuki; *; *
Nihon Kenchiku Gakkai Taikai Gakujutsu Koen Kogaishu, 0, p.45 - 46, 1994/09
no abstracts in English
