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Shibanuma, Kiyoshi; Arai, Takashi; Hasegawa, Koichi; Hoshi, Ryo; Kamiya, Koji; Kawashima, Hisato; Kubo, Hirotaka; Masaki, Kei; Saeki, Hisashi; Sakurai, Shinji; et al.
Fusion Engineering and Design, 88(6-8), p.705 - 710, 2013/10
Times Cited Count:10 Percentile:61.16(Nuclear Science & Technology)Endo, Kiyoshi*; Shibata, Yasushi*; Yamamoto, Tetsuya*; Nakai, Kei*; Matsumura, Akira*; Sato, Takahiro; Yokoyama, Akihito; Koka, Masashi; Okubo, Takeru; Yamazaki, Akiyoshi; et al.
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 86, 2012/01
Ishii, Yoji; Watanabe, Kazuhiko; Kamiya, Akira; Hayano, Akira; Mikake, Shinichiro; Takeuchi, Shinji; Ikeda, Koki; Yamamoto, Masaru; Sugihara, Kozo
JAEA-Technology 2010-044, 92 Pages, 2011/02
The "Mizunami Underground Research Laboratory" has been carrying out scientific research in granite to establish the technological basis for high-level radioactive waste disposal. To get reliable information on the rock mass geology and hydrogeology and on the bedrock conditions, a pilot borehole investigation was carried out before sinking the ventilation shaft. During this investigation, a zone with high hydraulic head and low hydraulic conductivity was observed at around GL-400m. To reduce water inflow during excavation, pre-excavation grouting with micro-fine cement was done in this region before sinking the Ventilation Shaft. Despite the high hydraulic head and the low hydraulic conductivity, effective reduction of water-inflow was achieved.
Ishii, Yoji; Mikake, Shinichiro; Kamiya, Akira; Watanabe, Kazuhiko; Nobuto, Jun*; Kusano, Takashi*
Dai-40-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koen Rombunshu (CD-ROM), p.185 - 190, 2011/01
The "Mizunami Underground Research Laboratory" has been carrying out scientific research in granite to establish the technological basis for high-level radioactive waste disposal. To get reliable information on the rock mass geology and hydrogeology and on the bedrock conditions, a pilot borehole investigation was carried out before sinking the Ventilation Shaft. A region with high hydraulic head and low hydraulic conductivity was intersected by the pilot borehole at around GL-400m during these investigations. To reduce water inflow during excavation, pre-excavation grouting with micro-fine cement was done in this region before sinking the ventilation shaft. Despite the high hydraulic head and the low hydraulic conductivity, effective reduction of water-inflow was achieved.
Nobuto, Jun*; Tsuji, Masakuni*; Kusano, Takashi*; Mikake, Shinichiro; Kamiya, Akira; Ishii, Yoji
Dai-40-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koen Rombunshu (CD-ROM), p.179 - 184, 2011/01
At Mizunami Underground Research Laboratory, the water inflow should be minimized, considering water treatment expense. Although cement grout has been applied to reduce water inflow up to 460 m depth, water inflow through small fractures which cement grout cannot penetrate can not be neglected at deeper underground. Liquid-type grout which has high durability as well as good penetrability was therefore tested at the depth of 300 m. Test results indicated that liquid-type grout could sufficiently reduce hydraulic conductivity of rock mass with less than 1Lu, and could keep improvement effect even after applied water pressure of more than 9 MPa was applied.
Morita, Yoshimune*; Kamiya, Chiho*; Sasaki, Toshinori*; Miyagi, Toyohiko*; Sugai, Toshihiko; Yanagida, Makoto*; Furusawa, Akira*; Fujiwara, Osamu*
Kikan Chirigaku, 62(4), p.195 - 210, 2010/12
It is assumed that the variation of temperature and the precipitation with the climate change may affect geological environment such as the subsurface water flow. Therefore, as well as global climate change from the past to the present, investigation technology to grasp local climate change is indispensable. A palynological study was carried out using the sediment core taken from the Okute Basin, located in the northeast of Mizunami Underground Research Laboratory. As a result, it was appeared that in a interglacial epoch, there was much precipitation around this area, and that in a glacial epoch, became colder and more arid, compared with Kinki region in the same latitude. This shows that the modern analog method with pollen data from the sediment of the inland basin is effective technique to estimate a local climate change.
Hoshino, Katsumichi; Ido, Takeshi*; Nagashima, Yoshihiko*; Shinohara, Koji; Ogawa, Hiroaki; Kamiya, Kensaku; Kawashima, Hisato; Tsuzuki, Kazuhiro*; Kusama, Yoshinori; Oasa, Kazumi; et al.
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 8 Pages, 2007/03
We report on the potential/density fluctuations in the JFT-2M tokamak. We identified a geodesic acoustic mode (GAM) and its electric field structure. The GAM interacts with the background turbulence in consistent with a drift wave - zonal flow theory. The GAM modulates the turbulence, and the suppression depends on the direction and gradient of the flow velocity in consistent with a theory. During the H-mode, the GAM disappears presumably due to the suppression of the turbulence. We analysed the low frequency potential oscillation during the H-mode. A wavelet analysis showed a low frequency characteristic potential fluctuations (several handred kHz), which disappears in the L-mode and at the occurence of ELM. Observed poloidal flow is about 20 times as large as that of the GAM during the H-mode. If the potential has a spatial inhomogineity, there is a possibility that this low frequency fluctuation comes from the EXB flow or the zonal flow.
Tsuzuki, Kazuhiro; Kamiya, Kensaku; Shinohara, Koji; Bakhtiari, M.*; Ogawa, Hiroaki; Kurita, Genichi; Takechi, Manabu; Kasai, Satoshi; Sato, Masayasu; Kawashima, Hisato; et al.
Nuclear Fusion, 46(11), p.966 - 971, 2006/11
Times Cited Count:16 Percentile:48.35(Physics, Fluids & Plasmas)no abstracts in English
Idesaki, Akira; Morishita, Norio; Ito, Hisayoshi; Kamiya, Tomihiro; Nakamoto, Tatsushi*; Kimura, Nobuhiro*; Makida, Yasuhiro*; Ogitsu, Toru*; Ohata, Hirokatsu*; Yamamoto, Akira*
AIP Conference Proceedings 824, p.330 - 334, 2006/03
Polyimide films and glass fiber reinforced plastics (GFRPs) are used as insulating or structural materials for superconducting magnets in a neutrino beam line of the Japan Proton Accelerator Research Complex (J-PARC). It is indispensable to evaluate radiation resistance of these materials, because they are required to keep their electrical and mechanical properties in a high radiation field of 30 kGy/year at low temperature of 4 K. In this work, the gas evolution resulting from chemical reactions induced in the polyimide films and GFRPs by ray irradiation at 77 K was investigated. It was found that the main component of the evolved gas is hydrogen. The amount of hydrogen evolved from the superconducting magnet system used in the neutrino beam line was estimated to be 0.37 mol/year (0.01 L/year as the volume of liquid hydrogen). It indicates that the hydrogen evolved from the organic materials does not influence on the operation of the helium purifying system.
Nakamoto, Tatsushi*; Idesaki, Akira; Morishita, Norio; Ito, Hisayoshi; Kamiya, Tomihiro; Kimura, Nobuhiro*; Makida, Yasuhiro*; Ogitsu, Toru*; Ohata, Hirokatsu*; Yamamoto, Akira*
AIP Conference Proceedings 824, p.225 - 232, 2006/03
Radiation resistance with respect to mechanical properties of organic materials used in the superconducting magnets for the 50 GeV - 750 kW proton beam line for the J-PARC neutrino experiment was studied. Specimens cooled at liquid nitrogen temperature of 77 K were irradiated by gamma rays beyond 10 MGy. The flexural strength of glass-fiber reinforced plastics (GFRPs), the tear strength of polyimide films and the tensile lap-shear strength of adhesive films were evaluated. It was verified that the organic materials used in the superconducting magnet have a sufficient radiation resistance, and the degradation of their mechanical properties after 10 years operation was estimated to be negligible.
Kasai, Satoshi*; Kamiya, Kensaku; Shinohara, Koji; Kawashima, Hisato; Ogawa, Hiroaki; Uehara, Kazuya; Miura, Yukitoshi; Okano, Fuminori; Suzuki, Sadaaki; Hoshino, Katsumichi; et al.
Fusion Science and Technology, 49(2), p.225 - 240, 2006/02
Times Cited Count:3 Percentile:24.11(Nuclear Science & Technology)The diagnostic system of JFT-2M has consisted of about 30 individual diagnostic instruments,which were used to study the plasma production, control, equilibrium, stability, confinement, plasma heating by NBI and/or RF (LH, ICRF, ECH) and current drive by RF. In these instruments, the motional Stark effect (MSE) polarimeter, charge exchanged recombination spectroscopy (CXRS), heavy-ion beam probe (HIBP), time of flight (TOF) neutral particle analyzer, etc. have contributed to make clear the improved mechanism of confinement such as H-mode and High Recycling Steady (HRS) H-mode, and to search the operational region of these modes.The infrared TV camera system and lost ion probe have played a very important role to investigate the heat load onto the walls due to ripple loss particles and escaping ions from core plasma, respectively.
Okada, Hiroshi*; Lee, H.-S.*; Wakahara, Akihiro*; Yoshida, Akira*; Oshima, Takeshi; Kamiya, Tomihiro
Solar Energy Materials and Solar Cells, 90(1), p.93 - 99, 2006/01
Times Cited Count:4 Percentile:20.61(Energy & Fuels)no abstracts in English
Morita, Yoshimune*; Kamiya, Chiho*; Sasaki, Toshinori*; Miyagi, Toyohiko*; Sugai, Toshihiko*; Yanagida, Makoto*; Furusawa, Akira*; Fujiwara, Osamu*; Moriya, Toshifumi*
Kikan Chirigaku, 58(3), p.123 - 139, 2006/00
A palynological study was carried out using the 25.3 m long sediment core taken from Okute basin, Mizunami city, central Japan. Sediments of this core were accumilated for more than ca. 300,000 years. From the results of pollen analysis, the sediments are devided into 15 pollen assemblages zones. These changes show a repetition of five warm and four cool stages. Each stage corresponds to MIS 9 to 1. Consequently, a temperature of MIS 5 was higher than those of MIS 7 and 9. A temperature of MIS 9 was not so high.
Okada, Hiroshi*; Natsume, Satoshi*; Wakahara, Akihiro*; Yoshida, Akira*; Oshima, Takeshi; Kamiya, Tomihiro
Proceedings of the 6th International Workshop on Radiation Effects on Semiconductor Devices for Space Application (RASEDA-6), p.147 - 150, 2004/10
no abstracts in English
Tsuzuki, Kazuhiro; Shinohara, Koji; Kamiya, Kensaku; Kawashima, Hisato; Sato, Masayasu; Kurita, Genichi; Bakhtiari, M.; Ogawa, Hiroaki; Hoshino, Katsumichi; Kasai, Satoshi; et al.
Journal of Nuclear Materials, 329-333(1), p.721 - 725, 2004/08
Times Cited Count:7 Percentile:45.11(Materials Science, Multidisciplinary)no abstracts in English
Tsuzuki, Kazuhiro; Kimura, Haruyuki; Kawashima, Hisato; Sato, Masayasu; Kamiya, Kensaku; Shinohara, Koji; Ogawa, Hiroaki; Hoshino, Katsumichi; Bakhtiari, M.; Kasai, Satoshi; et al.
Nuclear Fusion, 43(10), p.1288 - 1293, 2003/10
Times Cited Count:39 Percentile:74.23(Physics, Fluids & Plasmas)no abstracts in English
Harada, Satoshi*; Tamakawa, Yoshiharu*; Ishii, Keizo*; Tanaka, Akira*; Sato, Takahiro; Matsuyama, Shigeo*; Yamazaki, Hiromichi*; Kamiya, Tomihiro; Sakai, Takuro; Arakawa, Kazuo; et al.
Nuclear Instruments and Methods in Physics Research B, 189(1-4), p.437 - 442, 2002/04
Times Cited Count:1 Percentile:12.5(Instruments & Instrumentation)To study the interactions between the induction of radiation-induced apoptosis and trace elements kinetics, human leukemia cells were irradiated in vitro by Co rays, after which the cells were evaluated for the detection of apoptosis and trace element imaging was carried out. The frequency of apoptosis was obtained by microscopic assay using TUNEL staining. The trace element distribution in the cell was determined by micro-PIXE. In the early phase of apoptosis, the maximum level of Fe accumulation was observed in the cell stroma. In the mid to end phase, Fe accumulation was diminished, and instead, Ca accumulation increased and Zn decreased in the nucleus. There appear to be two steps for the development of apoptosis: (1) the signaling from cell stroma to nucleus by Fe or an Fe-containing enzyme; and (2) the degeneration of the nucleus by Ca-dependent enzyme, and release of Zn from digested nucleus. Those strong accumulations may be new markers for apoptosis.
Sakai, Takuro; Kamiya, Tomihiro; Oikawa, Masakazu*; Sato, Takahiro; Tanaka, Akira*; Ishii, Keizo*
Nuclear Instruments and Methods in Physics Research B, 190(1-4), p.271 - 275, 2001/09
Times Cited Count:66 Percentile:95.98(Instruments & Instrumentation)no abstracts in English
Takizawa, Daichi*; Takagi, Hitoshi*; Makita, Chikako*; Nakajima, Yuka*; Saito, Etsuko*; Oyama, Tatsuya*; Ichikawa, Takeshi*; Kakizaki, Akira*; Sato, Ken*; Mori, Masatomo*; et al.
no journal, ,
no abstracts in English
Mikake, Shinichiro; Yamamoto, Masaru; Ikeda, Koki; Kamiya, Akira; Takeda, Shinichi
no journal, ,
The Mizunami Underground Research Laboratory (MIU) is currently being constructed. During its construction, water inflow into the shafts of the MIU has been increasing and affecting the project progress. In order to reduce the water inflow into the shafts, borehole investigations and pre-excavation grouting have been conducted.