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Miyakawa, Kazuya; Nohara, Tsuyoshi; Tokiwa, Tetsuya; Yamazaki, Masanori*
International Journal of Rock Mechanics and Mining Sciences, 70, p.332 - 342, 2014/09
Times Cited Count：4 Percentile：30.82(Engineering, Geological)A large amount of groundwater drain induced by an excavation of an underground facility will influence parameters of site formations such as permeability. In this study, a spectral analysis was applied to long-term records of atmospheric response of pore pressure in order to obtain time history of rock permeability change at the Horonobe Underground Research Laboratory (URL) in Japan. This study revealed that the excavation of the URL has influenced aquifers around the URL, and has reduced the vertical hydraulic diffusivity in the aquifers. At the point of ca. 130 m distant away from the URL, the hydraulic diffusivity has decreased in approximately 70% after 5 years from start of excavation of the URL. At the point of ca. 860 m distant away from the URL, the vertical hydraulic diffusivity has decreased in approximately 26% even though pore pressure has not changed remarkably. These results indicate that groundwater consequently becomes difficult to flow, and then safe-side estimation with respect to geological disposal system was obtained. This study confirmed that long-term history of permeability change can be monitored by using long-period records of pore pressure and atmospheric pressure. During the development of a geological disposal system, which takes several tens of years, the vertical permeability can be monitored continuously from the start of the excavation through the post-closure of the repository.
Tamura, Jun; Ao, Hiroyuki; Asano, Hiroyuki; Ikegami, Masanori*; Maruta, Tomofumi; Miura, Akihiko; Morishita, Takatoshi; Oguri, Hidetomo; Ouchi, Nobuo; Sawabe, Yuki*; et al.
Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.377 - 380, 2013/08
In the J-PARC linac, almost all the cavities and magnets have been precisely aligned because the accelerator tunnel has been deformed by the 2011 Tohoku Earthquake. In the beam transport line called MEBT2 and A0BT at the downstream of the drift tube linac, the beam duct has been roughly aligned after the precise alignment of the quadruple doublets. During the first beam operation after the earthquake, remarkable beam loss and residual radiation have been recognized at the MEBT2 and A0BT. As the result of the duct position measurement, the misalignement including over 10 mm shift from the beam axis was found. By conducting the beam duct realignment, the beam loss and the residual radiation were successfully decreased. In this paper, the procedure of the beam duct alignment and the beam loss due to the misalignment are described.
Miyakawa, Kazuya; Nohara, Tsuyoshi; Tokiwa, Tetsuya; Yamazaki, Masanori*
Dai-13-Kai Iwa No Rikigaku Kokunai Shimpojiumu Koen Rombunshu (CD-ROM), p.1027 - 1032, 2013/01
Understanding of geological environment has been required for radioactive waste disposal, and the permeability of rock mass is one of the most important characteristics of disposal system. It is reported that rock permeability can be estimated by the spectral analysis of the records of pore pressure and atmospheric pressure. JAEA began the Horonobe Underground Research Laboratory (Horonobe URL) Project as part of efforts to enhance the reliability of technologies used during the geological disposal of HLW in Japan. In this study, a spectral analysis of vertical permeability in sedimentary formation around the underground facility has been carried out with seven years records of pore pressure and atmospheric pressure in the Horonobe URL. This study revealed that the excavation of URL has influenced groundwater layers around the URL, and has reduced the vertical hydraulic permeability in the layers. At a point approximately 130 m distant from the URL, it was found that hydraulic diffusivity has decreased by approximately 15 - 70% in five years since the excavation started. This study indicated that permeability change during the excavation of URL could be monitored via pore and atmospheric pressure records.
Yamamoto, Yoichi; Maekawa, Keisuke; Yokota, Hideharu; Yamazaki, Masanori
JAEA-Research 2011-042, 97 Pages, 2012/02
JAEA-Research-2011-042.pdf:11.05MB
The surface hydrogeological investigation has been carried out in and around the Horonobe Underground Research Laboratory area as a part of Horonobe URL project. Observations of meteorological, river flux, water quality, soil moisture and groundwater level have been continued in order to understand the groundwater recharge rate and groundwater flow in the shallow part, which are required for the setting of boundary and initial condition of the groundwater flow analysis. This report shows the summary of the surface hydrogeological investigation and results of recharge rates of investigation basins from December 2004 to November 2009 are calculated by using the water budget method. Spatial estimation of hydrological quantities for the groundwater recharge rate is demonstrated by the runoff analysis. As a result, average of the groundwater recharge rate of whole basins is estimated to 131mm/yr. Suggestive observations related to hydraulic properties of the geology and faults are obtained from consideration to the groundwater recharge rate for each basin.
Amano, Yuki; Yamamoto, Yoichi; Nanjo, Isao; Murakami, Hiroaki; Yokota, Hideharu; Yamazaki, Masanori; Kunimaru, Takanori; Oyama, Takahiro*; Iwatsuki, Teruki
JAEA-Data/Code 2011-023, 312 Pages, 2012/02
JAEA-Data-Code-2011-023.pdf:5.46MBJAEA-Data-Code-2011-023(errata).pdf:0.08MB
In the Horonobe Underground Research Laboratory (URL) Project, ground water from boreholes, river water and precipitation have been analyzed for the environmental monitoring since the fiscal year 2001. This report shows the data set of water chemistry since the fiscal year 2001 to the fiscal year 2010.
Imaizumi, Tomomi; Miyauchi, Masaru; Ito, Masayasu; Watahiki, Shunsuke; Nagata, Hiroshi; Hanakawa, Hiroki; Naka, Michihiro; Kawamata, Kazuo; Yamaura, Takayuki; Ide, Hiroshi; et al.
JAEA-Technology 2011-031, 123 Pages, 2012/01
JAEA-Technology-2011-031.pdf:16.08MB
The number of research reactors in the world is decreasing because of their aging. However, the planning to introduce the nuclear power plants is increasing in Asian countries. In these Asian countries, the key issue is the human resource development for operation and management of nuclear power plants after constructed them, and also the necessity of research reactor, which is used for lifetime extension of LWRs, progress of the science and technology, expansion of industry use, human resources training and so on, is increasing. From above backgrounds, the Neutron Irradiation and Testing Reactor Center began to discuss basic concept of a multipurpose low-power research reactor for education and training, etc. This design study is expected to contribute not only to design tool improvement and human resources development in the Neutron Irradiation and Testing Reactor Center but also to maintain and upgrade the technology on research reactors in nuclear power-related companies. This report treats the activities of the working group from July 2010 to June 2011 on the multipurpose low-power research reactor in the Neutron Irradiation and Testing Reactor Center and nuclear power-related companies.
Nov. 2009Yokota, Hideharu; Yamamoto, Yoichi; Yamazaki, Masanori; Maekawa, Keisuke
Nihon Chikasui Gakkai 2010-Nen Shuki Koenkai Koen Yoshi, p.160 - 165, 2010/11
no abstracts in English
Matsuda, Iwao*; Nakamura, Fumitaka*; Kubo, Keisuke*; Hirahara, Toru*; Yamazaki, Shiro*; Choi, W. H.*; Yeom, H. W.*; Narita, Hisashi*; Fukaya, Yuki; Hashimoto, Mie*; et al.
Physical Review B, 82(16), p.165330_1 - 165330_6, 2010/10
Times Cited Count：9 Percentile：40.66(Materials Science, Multidisciplinary)no abstracts in English
Ao, Hiroyuki; Hirano, Koichiro; Morishita, Takatoshi; Asano, Hiroyuki; Naito, Fujio*; Ueno, Akira; Ikegami, Masanori*; Hasegawa, Kazuo; Yamazaki, Yoshishige; Paramonov, V.*
Proceedings of 5th Annual Meeting of Particle Accelerator Society of Japan and 33rd Linear Accelerator Meeting in Japan (CD-ROM), p.494 - 496, 2008/00
The J-PARC ACS cavity consists of many cell parts. For the mass production, the ACS requires about 1300 cell parts, so that it is important to reduce the machining time. In the previous ACS model, it took about three hours per one coupling slot. We, therefore, optimized the slot design, the tolerance, and the machining process. As a result, the machining time reduced to forty-five minutes per one slot. The four test cells were fabricated to measure the frequencies and Q-values, and these results were compared with the electromagnetic analysis with the Microwave Studio. Between the analysis and the measurement, the differences are 11.5 MHz and 45 MHz, respectively, for the accelerating mode, and for the coupling mode.
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
JAEA-Technology-2006-030.pdf:10.69MB
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 B
C/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.
Ao, Hiroyuki; Ueno, Akira; Morishita, Takatoshi; Hasegawa, Kazuo; Yamazaki, Yoshishige; Ikegami, Masanori*
Proceedings of 2nd Annual Meeting of Particle Accelerator Society of Japan and 30th Linear Accelerator Meeting in Japan, p.332 - 334, 2005/07
The first ACS module consists of two 5-cells ACS tanks and a 5-cells bridge cavity for the buncher module. Three RF tuners are installed to the bridge cavity for fine RF tuning. An operating frequency should be tuned to 972 MHz within the fine-tuning range before a brazing process in a factory. The tuning procedure has been studied with RF simulation analysis and cold-model measurements for ACS and bridge cells. This paper describes RF tuning results, fabrication status and related development items.
Ao, Hiroyuki; Morishita, Takatoshi; Ueno, Akira; Hasegawa, Kazuo; Yamazaki, Yoshishige; Ikegami, Masanori*; Paramonov, V.*
Proceedings of 2005 Particle Accelerator Conference (PAC '05) (CD-ROM), p.2684 - 2686, 2005/00
J-PARC Linac starts with 180-MeV SDTL temporary, and it is upgraded to 400-MeV with 21 ACS (Annular Coupled Structure) modules and two ACS bunchers and two debunchers. First buncher module is under fabrication, and second buncher and a few accelerating modules are also planed until FY2006. The first ACS module consists of two 5-cell ACS tanks and a 5-cell bridge cavity for the buncher module. Three RF tuners are installed to the bridge cavity for fine RF tuning. An operating frequency should be tuned to 972 MHz within the fine-tuning range before a brazing process in a factory. The tuning procedure has been studied with RF simulation analysis and cold-model measurements for ACS and bridge cells. This paper describes RF tuning results, fabrication status and related development items.
Hino, Ryutaro; Yokomizo, Hideaki; Yamazaki, Yoshishige; Hasegawa, Kazuo; Suzuki, Hiromitsu; Soyama, Kazuhiko; Hayashi, Makoto*; Haga, Katsuhiro; Kaminaga, Masanori; Sudo, Yukio*; et al.
Nihon Kikai Gakkai-Shi, 107(1032), p.851 - 882, 2004/11
no abstracts in English
Ao, Hiroyuki; Ueno, Akira; Morishita, Takatoshi; Hasegawa, Kazuo; Yamazaki, Yoshishige; Ikegami, Masanori*; Hayashizaki, Noriyosu*
Proceedings of 1st Annual Meeting of Particle Accelerator Society of Japan and 29th Linear Accelerator Meeting in Japan, p.323 - 325, 2004/08
no abstracts in English
Ao, Hiroyuki; Akikawa, Hisashi; Ueno, Akira; Hasegawa, Kazuo; Yamazaki, Yoshishige; Ikegami, Masanori*; Noguchi, Shuichi*; Hayashizaki, Noriyosu*; Paramonov, V.*
Proceedings of 22nd International Linear Accelerator Conference (LINAC 2004), p.75 - 77, 2004/00
The J-PARC (Japan Proton Accelerator Research Complex) LINAC will be commissioned with energy of 181-MeV using 50-keV ion source, 3-MeV RFQ, 50-MeV DTL and 181-MeV SDTL (Separated DTL) on September 2006. It is planed to be upgraded by using a 400-MeV ACS (Annular Coupled Structure), which is a high-beta structure most suitable for the J-PARC, in a few years from the commissioning. The first ACS type cavity, which will be used as the first buncher between the SDTL and the ACS, is under fabrication. Detailed design and tuning procedure of ACS cavities has been studied with RF simulation analysis and cold-model measurements. The results of cold-model measurements, fabrication status, and related development items are described in this paper.
Hayashizaki, Noriyosu*; Ao, Hiroyuki; Akikawa, Hisashi; Hasegawa, Kazuo; Yamazaki, Yoshishige; Ikegami, Masanori*
Proceedings of 28th Linear Accelerator Meeting in Japan, p.75 - 77, 2003/08
no abstracts in English
Sato, Toshinori; Mikake, Shinichiro; Sakamaki, Masanori; Aoki, Kazuhiro; Yamazaki, Shinichi; Shigeta, Naotaka; Takeda, Seietsu
9th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM '03), p.1333 - 1339, 2003/00
This paper shows current status of Mizunami Underground Research Laboratory, especially design and construction plan of underground facility.
Joshi, S. C.*; Paramonov, V.*; Skassyrskaya, A.*; Hayashizaki, Noriyosu*; Ikegami, Masanori*; Yamazaki, Yoshishige
Proceedings of 21st International Linac Conference, p.216 - 218, 2003/00
The normal conducting coupled-cavity linac with the Annular Coupled Structure (ACS) is adopted for 190-400 MeV part of high intensity proton linac for the JAERI/KEK Joint Project. The operating frequency is 972 MHz and the 23 modules will be constructed. The basic configuration is based on that investigated for L-band (1296 MHz) in the previous Japan Hadron Project research. However, the structure design is revised and optimized in order to meet requirements of reliability, operation efficiency and cost reduction for the newly proposed Joint Project. As the results of development, the transverse dimensions of the ACS tank are reduced sufficiently with the improvement in RF characteristics. The structure segmentation and essential points of the design are described.
Hayashizaki, Noriyosu*; Ao, Hiroyuki; Hasegawa, Kazuo; Yamazaki, Yoshishige; Ikegami, Masanori*; Kato, Takao*; Paramonov, V.*
Proceedings of 21st International Linac Conference, p.234 - 236, 2003/00
The normal conducting coupled-cavity linac with the Annular Coupled Structure (ACS) is adopted for 190-400 MeV part of high intensity proton linac for the JAERI/KEK Joint Project. The operating frequency is 972 MHz and the 23 modules will be constructed. The basic configuration is based on that investigated for L-band (1296 MHz) in the previous Japan Hadron Project research. However, the structure design is revised and optimized in order to meet requirements of reliability, operation efficiency and cost reduction for the newly proposed Joint Project. As the results of development, the transverse dimensions of the ACS tank are reduced sufficiently with the improvement in RF characteristics. The structure segmentation and essential points of the design are described.
Araki, Masanori; Akiba, Masato; Seki, Masahiro; Dairaku, Masayuki; Ise, Hideo*; Yamazaki, Seiichiro*; Tanaka, Shigeru;
Fusion Engineering and Design, 19, p.101 - 109, 1992/00
Times Cited Count：15 Percentile：78.31(Nuclear Science & Technology)no abstracts in English
