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Ogura, Koya*; Hosoda, Masahiro*; Tamakuma, Yuki*; Suzuki, Takahito*; Yamada, Ryohei; Negemi, Ryoju*; Tsujiguchi, Takakiyo*; Yamaguchi, Masaru*; Shiroma, Yoshitaka*; Iwaoka, Kazuki*; et al.
International Journal of Environmental Research and Public Health, 18(3), p.978_1 - 978_16, 2021/02
Times Cited Count:7 Percentile:68.83(Environmental Sciences)Tobita, Kenji; Nishio, Satoshi*; Enoeda, Mikio; Nakamura, Hirofumi; Hayashi, Takumi; Asakura, Nobuyuki; Uto, Hiroyasu; Tanigawa, Hiroyasu; Nishitani, Takeo; Isono, Takaaki; et al.
JAEA-Research 2010-019, 194 Pages, 2010/08
This report describes the results of the conceptual design study of the SlimCS fusion DEMO reactor aiming at demonstrating fusion power production in a plant scale and allowing to assess the economic prospects of a fusion power plant. The design study has focused on a compact and low aspect ratio tokamak reactor concept with a reduced-sized central solenoid, which is novel compared with previous tokamak reactor concept such as SSTR (Steady State Tokamak Reactor). The reactor has the main parameters of a major radius of 5.5 m, aspect ratio of 2.6, elongation of 2.0, normalized beta of 4.3, fusion out put of 2.95 GW and average neutron wall load of 3 MW/m. This report covers various aspects of design study including systemic design, physics design, torus configuration, blanket, superconducting magnet, maintenance and building, which were carried out increase the engineering feasibility of the concept.
Tobita, Kenji; Nishio, Satoshi; Enoeda, Mikio; Kawashima, Hisato; Kurita, Genichi; Tanigawa, Hiroyasu; Nakamura, Hirofumi; Honda, Mitsuru; Saito, Ai*; Sato, Satoshi; et al.
Nuclear Fusion, 49(7), p.075029_1 - 075029_10, 2009/07
Times Cited Count:137 Percentile:97.72(Physics, Fluids & Plasmas)Recent design study on SlimCS focused mainly on the torus configuration including blanket, divertor, materials and maintenance scheme. For vertical stability of elongated plasma and high beta access, a sector-wide conducting shell is arranged in between replaceable and permanent blanket. The reactor adopts pressurized-water-cooled solid breeding blanket. Compared with the previous advanced concept with supercritical water, the design options satisfying tritium self-sufficiency are relatively scarce. Considered divertor technology and materials, an allowable heat load to the divertor plate should be 8 MW/m or lower, which can be a critical constraint for determining a handling power of DEMO (a combination of alpha heating power and external input power for current drive).
Ishida, Takekazu*; Matsushima, Yoshiaki*; Shimizu, Makoto*; Hayashi, Masahiko*; Ebisawa, Hiromichi*; Sato, Osamu*; Kato, Masaru*; Koyama, Tomio*; Machida, Masahiko; Sato, Kazuo*; et al.
Physica C, 468(7-10), p.576 - 580, 2008/04
Times Cited Count:3 Percentile:17.18(Physics, Applied)The extended Little-Parks effect of superconducting network is known as a periodic variation as a function of magnetic field. Superconducting Pb honeycomb networks of matching field 0.106 G and triangular microhole lattice of Pb of matching field 0.425 G have been fabricated by the combination of electron-beam lithography and a lift-off process of evaporated Pb films. The application of magnetic field corresponds to the vortex filling into superconducting networks. We measured the magnetization of the networks systematically by using a SQUID magnetometer. We found that flux jump appears rather periodically as a function of magnetic field. Flux jumps may be induced by a periodic decrease of the critical current density of the network. To the authors' knowledge, this is for the first time to observe the regular flux jumps due to the critical current modification coming from the extended Little-Parks effect of the superconducting networks.
Kobune, Masafumi*; Fukushima, Koji*; Yamaji, Toru*; Tada, Hideto*; Yazawa, Tetsuo*; Fujisawa, Hironori*; Shimizu, Masaru*; Nishihata, Yasuo; Matsumura, Daiju; Mizuki, Junichiro; et al.
Journal of Applied Physics, 101(7), p.074110_1 - 074110_6, 2007/04
Times Cited Count:8 Percentile:33.28(Physics, Applied)no abstracts in English
Hamamoto, Shimpei; Iigaki, Kazuhiko; Shimizu, Atsushi; Sawahata, Hiroaki; Kondo, Makoto; Oyama, Sunao; Kawano, Shuichi; Kobayashi, Shoichi; Kawamoto, Taiki; Suzuki, Hisashi; et al.
JAEA-Technology 2006-030, 58 Pages, 2006/03
During normal operation of High Temperature engineering Test Reactor (HTTR) in Japan Atomic Energy Agency (JAEA), the reactivity is controlled by the Control Rods (CRs) system which consists of 32 CRs (16 pairs) and 16 Control Rod Drive Mechanisms (CRDMs). The CR system is located in stand-pipes accompanied by the Reserved Shutdown System (RSS). In the unlikely event that the CRs fail to be inserted, the RSS is provided to insert BC/C pellets into the core. The RSS shall be designed so that the reactor should be held subcriticality from any operation condition by dropping in the pellets. The RSS consists of BC/C pellets, hoppers which contain the pellets, electric plug, driving mechanisms, guide tubes and so on. In accidents when the CRs cannot be inserted, an electric plug is pulled out by a motor and the absorber pellets fall into the core by gravity. A trouble, malfunction of one RSS out of sixteen, occurred during a series of the pre-start up checks of HTTR on February 21, 2005. We investigated the cause of the RSS trouble and took countermeasures to prevent the issue. As the result of investigation, the cause of the trouble was attributed to the following reason: In the motor inside, The Oil of grease of the multiplying gear flowed down from a gap of the oil seal which has been deformed and was mixed with abrasion powder of brake disk. Therefore the adhesive mixture prevented a motor from rotating.
Shimizu, Ryo; Takaya, Akikazu; Shirozu, Hidetomo; Uchida, Naoki; Tanaka, Kosuke; Yamaguchi, Akira; Aoto, Kazumi; Watahiki, Masaru
Nihon Genshiryoku Gakkai Wabun Rombunshi, 4(3), p.203 - 212, 2005/09
It was occurred that process solution leaked from the steam jet in the acid recovery process of Tokai reprocessing plant. So we retrieved the jet from the cell and observed the inside. As a result, it was revealed that a defect by corrosion, which penetrated the inside of the structure, arose from the steam nozzle root in the suction room of the jet. To ascertain why such failure occurred, we carried out observation of metallurgical structure of the jet, an analysis of temperature distribution of the structure involving verification using mock-ups and evaluation of material by corrosion test. Consequently, the origin of the corrosion defect was pin hole which was occurred on the surface of the end of the material at the steam nozzle root, where nitric acid fluid was contacted, and then the defect progressed along the temperature of about 120 of the structure. Anisotropy of the material, possibly originating in the manufacturing process, was observed from the result of evaluation of material by corrosion test. Finally, we devised a new design of improved corrosion resistance on the result of the whole investigations.
Hara, Keigo*; Adachi, Takeshi*; Akimune, Hidetoshi*; Daito, Izuru*; Fujimura, Hisako*; Fujita, Yoshitaka*; Fujiwara, Mamoru; Fushimi, Kenichi*; Hara, Kaoru*; Harakeh, M. N.*; et al.
Physical Review C, 68(6), p.064612_1 - 064612_9, 2003/12
Times Cited Count:11 Percentile:58.08(Physics, Nuclear)no abstracts in English
Zegers, R. G. T.*; Sumihama, Mizuki*; Ahn, D. S.*; Ahn, J. K.*; Akimune, Hidetoshi*; Asano, Yoshihiro; Chang, W. C.*; Dat, S.*; Ejiri, Hiroyasu*; Fujimura, Hisako*; et al.
Physical Review Letters, 91(9), p.092001_1 - 092001_4, 2003/08
Times Cited Count:128 Percentile:94.9(Physics, Multidisciplinary)no abstracts in English
Nakano, Takashi*; Ahn, D. S.*; Ahn, J. K.*; Akimune, Hidetoshi*; Asano, Yoshihiro; Chang, W. C.*; Date, S.*; Ejiri, Hiroyasu*; Fujimura, Hisako*; Fujiwara, Mamoru; et al.
Physical Review Letters, 91(1), p.012002_1 - 012002_4, 2003/07
Times Cited Count:1006 Percentile:99.86(Physics, Multidisciplinary)no abstracts in English
Tsutagi, Koichi; Shimizu, Ryo; Sugiyama, Takayuki; Nakazawa, Y.; Tanaka, Hitoshi; Watahiki, Masaru; Muto, Hideyo
Saikuru Kiko Giho, (21), p.33 - 40, 2003/00
This report describes the outline of the measurement system of HALW storage tank and a measurement situation, and a thickness measurement result.
Tsuji, Hiroshi; Okuno, Kiyoshi*; Thome, R.*; Salpietro, E.*; Egorov, S. A.*; Martovetsky, N.*; Ricci, M.*; Zanino, R.*; Zahn, G.*; Martinez, A.*; et al.
Nuclear Fusion, 41(5), p.645 - 651, 2001/05
Times Cited Count:57 Percentile:83.02(Physics, Fluids & Plasmas)no abstracts in English
Aoki, Kenji*; Hibiya, Keisuke*; Shiogama, Yukihiro*; Toida, Masaru*; Yamamoto, T.*; Yoshida, Hiroshi*; Banno, K.*; Kubota, T.*; Shimizu, Y.*; Okutsu, Kazuo*; et al.
PNC TJ1100 94-001, 69 Pages, 1994/02
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Naganuma, Takashi; Iwatsuki, Teruki; Shimizu, Satoru*; Akiyama, Masaru*; Ishijima, Yoji*
no journal, ,
Microbial communities affect geochemical and hydrogeological processes in deep aquifers, and have been characterized mainly by genetic approaches as well as activity measurements. We have analyzed 16S rDNA assemblages from hydrologically isolated aquifers of porous-but-less-permeable strata in the northernmost part of Japan, and revealed distinctive microbial communities including methanogens and so-far-uncultured species. We have also collected 16S rDNA of the 0.2-micron m-passing-but-0.1-micron m-captured microorganisms from sedimentary and granite rock aquifers in a uranium deposit area of central Japan. In situ activities are characterized and measured by culture-based physiological approaches, which have many limitations and biases though. We have developed a quantification of mRNA for redox-responsive proteins of Fe(III)-reducing bacteria collected from a deep aquifer. This approach is applicable to other aquifer processes such as reduction of nitrate, sulfate, CO, etc.
Niimi, Kenichiro; Nakajima, Hideo; Hamada, Kazuya; Takano, Katsutoshi; Okuno, Kiyoshi; Kakui, Hideo*; Yamaoka, Hiroto*; Chida, Yutaka*; Seto, Masaru*; Soejima, Koji*; et al.
no journal, ,
no abstracts in English
Suzuki, Yutaka; Kuno, Takehiko; Nemoto, Hirokazu*; Okano, Masanori; Goto, Yuichi; Igarashi, Kazuto*; Shimizu, Yasuyuki; Suda, Shizuka; Yamada, Keiji; Watahiki, Masaru
no journal, ,
no abstracts in English