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Sugihara, Kozo
JAEA-Review 2009-004, p.6 - 13, 2009/05
no abstracts in English
Matsui, Hiroya; Takeuchi, Shinji; Iyatomi, Yosuke; Sugihara, Kozo
no journal, ,
This study carried out to confirm the applicability of existing grouting technology for reducing of inflow and find the investigation methods as a part of contract study with METI. The site, where called refuge niche, was located at 200 m sub-stage in Mizunami URL. Pre-excavation grouting was performed before excavation of refuge niche and the various investigations/modeling were carried out for pre-excavation grouting area around refuge niche. The results suggested that existing grouting technology is applicable to reduce inflow and the permeability in grouted area may decrease max, two order of magnitudes.
Hanamuro, Takahiro; Yamada, Kunimi; Umeda, Koji
no journal, ,
(U-Th)/He dating method is one of the radioactive dating methods by using alpha-decay nuclides and producing 
He, and it is practically applied at apatite and zircon those closed temperature are determined. This method is also expected to apply the effect of low-temperature (ca.100
C) geothermal activities, that is important for maintenance of overpack performance at geological disposal, or determination of fault activities, etc.. There are no facilities for dating this method in Japan, so, JAEA started system installation and research for the measurement from fiscal year 2006, aiming at the practical use of (U-Th)/He dating technique at the first case in Japan. The prospect of practical use of the dating for zircon was obtained now. Age-known samples are already analyzed and geological samples are analyzing. This dating method for apatite are scheduled to be established in this fiscal year.
Matsui, Hiroya; Mikake, Shinichiro; Asai, Hideaki; Sugihara, Kozo
no journal, ,
In the construction phase of the MIU project, engineering studies have focused on research into design and construction technologies for deep underground. The main subjects consist of the following: "Demonstration of the design methodology", "Demonstration of existing and supplementary excavation methods", "Demonstration of countermeasures during excavation" and "Demonstration of safe construction". In the FY 2007, identification and evaluation of the subjects for this study were carried out to optimize future research work. Specific studies have been performed as well. Based on these studies, future research focused on the four subject areas has been identified. The design methodology in the surface-based investigation phase was verified to 200 m depth. Evaluation of countermeasures and studies of concepts for the estimation of the influence of high differential water pressures, long-term maintenance and risk management have been proposed with respect to the geological disposal project.
Nohara, Tsuyoshi
no journal, ,
The Japanese islands are located in the tectonically active Circum-Pacific Mobile Belt. Therefore, special consideration is given to the long-term stability of the geological environments in Japan. Development of investigation/evaluation technologies for geotectonic events has been carried out to evaluate the long-term stability of the geological environments in Japan. The result of the case study concerning a systematic investigation/evaluation technologies are reported.
Hasegawa, Ken; Kunitomo, Takahiro; Nakajima, Takahiro
no journal, ,
no abstracts in English
Tajikara, Masayoshi
no journal, ,
no abstracts in English
Ninomiya, Atsushi; Negi, Tateyuki; Umeda, Koji
no journal, ,
Although there is no evidence of volcanism in the Noto Peninsula since the late Miocene, the peninsula has long been known to be atypical of non-volcanic regions, as indicated by the presence of high-temperature hot springs. In order to provide geophysical constraints on the heat source for the hydrothermal activity, the wide-band magnetotelluric soundings were carried out. A three-dimensional interpretation throughout the Noto Peninsula illustrated gnessises and granite of Paleozoic and Mesozoic age, as resistive zones extended the upper to middle crust. The low helium isotopic compositions of 12 gas and water samples indicate high crustal contribution. These results suggest a plausible heat source for high-temperature hot springs in non-volcanic regions is radiogenic heat production within the lithosphere.
Saito, Tatsuo; Suzuki, Mototaka; Nishizawa, Akimitsu*; Ishimaru, Tsuneari
no journal, ,
no abstracts in English
Kagohara, Kyoko; Kurosawa, Hideki; Ishimaru, Tsuneari; Nohara, Tsuyoshi
no journal, ,
Assessment of the effects of earthquakes and faulting on the deep geological environment is absolutely essential for site selection and design of high-level radioactive waste repositories in Japan. For thrust faults, there are widely deformations in strata or surface, complex geological structure caused by blind thrust, and lateral propagation and growth. Thus, it is important to understand the morphic character and history of thrust faults, based on the tectonic landforms and underground structures. Here, we presented the results of the case study at the Yokote basin fault zone that is a typical thrust fault of Japan. It reports on the relation between geographical features and underground structure of the Yokote basin fault zone.
gas emission due to fault activityKurosawa, Hideki; Ishimaru, Tsuneari; Niwa, Masakazu; Shimada, Koji; Kagohara, Kyoko
no journal, ,
no abstracts in English
Matsui, Hiroya; Hirano, Toru; Nakama, Shigeo; Yamada, Atsuo*; Seno, Yasuhiro*; Sato, Toshinori*
no journal, ,
This is the poster describing the interim results of rock mechanics investigations in construction phase at Mizunami Underground laboratory. Mainly the poster accounts for the measurement of in-situ stress and the laboratory test of rock physical or mechanical properties at GL.-100m (sedimentary rock layer). Additionally future rock mechanics investigations at GL.-200m was informed. The purpose of investigation, and what a contribution to disposal technology were explained too.
Iyatomi, Yosuke; Ogata, Nobuhisa; Sugihara, Kozo; Hoshina, Hiroyuki; Seko, Noriaki; Kasai, Noboru; Ueki, Yuji; Tamada, Masao
no journal, ,
no abstracts in English
Mikake, Shinichiro
no journal, ,
no abstracts in English
Hama, Katsuhiro
no journal, ,
The construction phase (Phase II) of Mizunami Underground Research Laboratory project has been carried out since 2002. The lessons learnt from Phase II investigations should be properly reflected in the implementation of the HLW disposal. We propose possible idea to reflect our knowledge and experiences.
Hama, Katsuhiro; Iwatsuki, Teruki; Hasegawa, Takuma*; Nakata, Kotaro*; Tomioka, Yuichi*; Goto, Kazuyuki*
no journal, ,
The dating of groundwater has been carried out by the measurement of radionuclides in groundwater in and around the Mizunami underground research laboratory.
Mizuno, Takashi; Hagiwara, Hiroki; Sai, Masataka
no journal, ,
no abstracts in English
Hara, Masato; Mikake, Shinichiro; Ikeda, Koki
no journal, ,
Pregrauting between 220m from 200m in depth of ventilation shaft was executed as a water inflow measures, and the water controlling effect was confirmed.
Oyama, Takuya; Takeuchi, Ryuji; Matsuki, Koji*; Arai, Takashi*
no journal, ,
no abstracts in English
Keya, Hiromichi; Takeuchi, Ryuji; Toya, Naruhisa; Sato, Atsuya; Saegusa, Hiromitsu; Oyama, Takuya; Kosaka, Hiroshi
no journal, ,
no abstracts in English
