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Tachi, Yukio; Ito, Tsuyoshi*; Akagi, Yosuke*; Sato, Hisao*; Martin, A. J.*
Water Resources Research, 54(11), p.9287 - 9305, 2018/11
Times Cited Count：6 Percentile：26.02(Environmental Sciences)Effects of fine-scale surface alterations on radionuclide migration in fractured crystalline rocks were investigated by a comprehensive approach coupling a series of laboratory tests, microscopic observations and modelling, using a single fractured granodiorite sample from the Grimsel Test Site, Switzerland. Laboratory tests including through-diffusion, batch sorption and flow-through tests using five tracers indicated that tracer retention was consistently in the sequence of HDO, Se, Cs, Ni, Eu, and as well as showing the existence of a diffusion-resistance layer near the fracture surface, cation excess and anion exclusion effects for diffusion. Microscale heterogeneities in structural properties around the fracture were clarified quantitatively by coupling X-ray CT and EPMA. A three layer model including weathered vermiculite, foliated mica and undisturbed matrix layers, and their properties such as porosity, sorption and diffusion parameters, could provide a reasonable interpretation for breakthrough curves and concentration distributions near fracture surface of all tracers, measured in flow-through tests.
Hiyama, Kazuhisa; Hanawa, Nobuhiro; Kurosawa, Akihiko; Eguchi, Shohei; Hori, Naohiko; Kusunoki, Tsuyoshi; Ueda, Hisao; Shimada, Hiroshi; Kanda, Hiroaki*; Saito, Isamu*
JAEA-Technology 2013-045, 32 Pages, 2014/02
JAEA-Technology-2013-045.pdf:5.83MB
This report summarizes regarding to develop of real-time multifunctional access control system which is able to manage worker's access control and exposure dose at real-time in the reactor building, besides worker's location and worker might be fall down by accident.
Tsuda, Shuichi; Yoshida, Tadayoshi; Nakahara, Yukio; Sato, Tetsuro; Seki, Akiyuki; Matsuda, Norihiro; Ando, Masaki; Takemiya, Hiroshi; Tanigaki, Minoru*; Takamiya, Koichi*; et al.
JAEA-Technology 2013-037, 54 Pages, 2013/10
JAEA-Technology-2013-037.pdf:4.94MB
JAEA has been performing dose rate mapping in air using a car-borne survey system KURAMA-II. The KURAMA system is a GPS-aided mobile radiation monitoring system that has been newly developed by Kyoto University Research Reactor Institute in response to the nuclear disaster. The KURAMA system is composed of an energy-compensated scintillation survey meter for measuring dose rate, electric device for controlling both the dose rates and the position data from a GPS module, a computer server for processing and analyzing data from KURAMA, and client PCs for providing for end users. The KURAMA-II has been improved in small-packaging, durability, and automated data transmission. In consequence, dose rate mapping in wide area has become possible in shorter period of time. This report describes the construction of KURAMA-II, its application and a suggestion of how to manage a large number of KURAMA-II.
Mamada, Yutaka*; Nishigami, Kinya*; Ito, Hisao*; Kuwahara, Yasuto*
Geodynamics of Atotsugawa Fault System, p.93 - 102, 2007/00
The explosion experiments at the Mozumi-Siukenobe fault enabled us to collect high quality records using the linear seismometer array installed in an underground tunnel at a depth of 300 m. The seismograms contained high frequency components of up to 25 Hz. The phases interpreted as fault zone head waves, direct-
waves propagating within the fault zone, and fault zone trapped waves were clearly found on the seismograms. Using such high quality records, we could perform fault zone wave modeling. We successfully simulated almost the characteristics on the observed seismograms with high frequency components of up to 25 Hz and revealed the complex structure of the Mozumi-Sukenobe fault zone terminating just east of the site SP1. This indicates the possibility of modeling for high frequency seismic waves that excited at the fault zone. According to this modeling, the precise -waves velocity adjacent to the fault zone and velocity contrast of waves between the wall rock and fault zone were estimated. The modeling also indicates the possibility of detecting fault zone discontinuity, in other words, the segmentation of fault at depth.
Nishigami, Kinya*; Ito, Hisao*; Kuwahara, Yasuto*; Mizuno, Takashi*; Mamada, Yutaka*
Geodynamics of Atotsugawa Fault System, p.149 - 156, 2007/00
no abstracts in English
Ito, Hisao; ;
Tectonophysics, (378), p.209 - 222, 2004/01
None
Ito, Hisao; ;
American Geophysical Union 2002 Fall Meeting, P. F990, 2002/12
Delineating the finestructure of fault is necessary to understand the process of earthquake occurrence. Fault zone waves which consist of fault zone head waves propagating along material discontinuity interfaces, direct body waves propagating within a low-velocity fault zone and trapped waves due to seismic energy trapped in a low-velocity fault zone are sensitive to a structure of fault zone. The modeling of these waves is one of the useful procedures to reveal a fine structure of fault zone. We use the 3D finite difference (FD) method to simulate fault zone waves and to determine a fault zone structure. A linear array consisting of 32 three component seismometers spacing roughly 15m is across the Mozumi-Sukenobu fault in research tunnel at a depth of 300m. In previous study, using the se
Kuwahara, Yasuto*; Ito, Hisao
Earth Planets and Space, 54, p.1045 - 1048, 2002/00
Times Cited Count：9 Percentile：25.21(Geosciences, Multidisciplinary)None
Ito, Hisao; ;
Earth Planets and Space, 54, p.1055 - 1058, 2002/00
Times Cited Count：8 Percentile：23.08(Geosciences, Multidisciplinary)None
Ito, Hisao; ;
EOS Trans., 82(47), 0 Pages, 2001/00
None
Nakamura, Takehiko; Saito, Shinzo; Emori, Yasubumi*; Namba, Hisao*;
JAERI-M 93-068, 37 Pages, 1993/03
no abstracts in English
Isoya, Junichi*; Kanda, Hisao*; ; S.C.Lawson*; ; Ito, Hisayoshi; Morita, Yosuke
Physical Review B, 45(3), p.1436 - 1439, 1992/01
Times Cited Count：108 Percentile：95.69(Materials Science, Multidisciplinary)no abstracts in English
; Nakagawa, Rinshi; ; ; ; ; Saito, Makoto; Ojima, Hisao
PNC TN841 85-05, 116 Pages, 1985/02
no abstracts in English
Tachi, Yukio; Ito, Tsuyoshi*; Fukatsu, Yuta; Akagi, Yosuke*; Sato, Hisao*; Martin, A. J.*
no journal, ,
Ojima, Hisao; Ito, Masanori; Takahashi, Saburo; Asakura, Koichi; Aoki, Yoshikazu
no journal, ,
no abstracts in English
Wada, Takeshi; Araake, Yuji; Ueda, Hisao; Takasaki, Koji; Shimizu, Takehiko; Ito, Kimio
no journal, ,
no abstracts in English
Tachi, Yukio; Ito, Tsuyoshi; Akagi, Yosuke*; Sato, Hisao*; Martin, A. J.*
no journal, ,
The effects of heterogeneity at fracture surface on radionuclides migration in fractured crystalline rocks was investigated by laboratory migration experiments, microscopic observations and detailed modelling, using a single fractured granodiorite sample from the Grimsel Test Site (GTS), Switzerland. The tracer migration behaviors in fracture and matrix parts were evaluated by series of laboratory experiments including through-diffusion and flow-through experiments. Mineral distributions from fracture surface to matrix were evaluated by X-ray CT, and were validated by comparing the elemental mapping measured by EPMA. Based on the microscopic observations by X-ray CT and EPMA, the aperture and connectivity in fracture and minerals distribution near fracture surface were quantitatively evaluated. The heterogeneous multi-layered model assuming a weathered vermiculite zone, a foliated mica zone and rock matrix was possible to provide a reasonable interpretation for measured breakthrough curves of all tracers.
Tachi, Yukio; Ito, Tsuyoshi*; Fukatsu, Yuta; Akagi, Yosuke*; Sato, Hisao*; Hu, Q.*; Martin, A. J.*
no journal, ,
