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JAEA Reports

Horonobe Underground Research Laboratory Project; Synthesis of Phase II (Construction Phase) investigations to a depth of 350m

Sato, Toshinori; Sasamoto, Hiroshi; Ishii, Eiichi; Matsuoka, Toshiyuki; Hayano, Akira; Miyakawa, Kazuya; Fujita, Tomoo*; Tanai, Kenji; Nakayama, Masashi; Takeda, Masaki; et al.

JAEA-Research 2016-025, 313 Pages, 2017/03

JAEA-Research-2016-025.pdf:45.1MB

The Horonobe Underground Research Laboratory (URL) Project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of relevant disposal technologies through investigations of the deep geological environment within the host sedimentary formations at Horonobe, northern Hokkaido. This report summarizes the results of the Phase II investigations carried out from April 2005 to June 2014 to a depth of 350m. Integration of work from different disciplines into a "geosynthesis" ensures that the Phase II goals have been successfully achieved and identifies key issues that need to made to be addressed in the Phase II investigations Efforts are made to summarize as many lessons learnt from the Phase II investigations and other technical achievements as possible to form a "knowledge base" that will reinforce the technical basis for both implementation and the formulation of safety regulations.

Journal Articles

EM-ACROSS system and corresponding tensor transfer functions in diffusion field region

Nakajima, Takahiro; Kunitomo, Takahiro; Nagao, Hiromichi*; Kumazawa, Mineo; Shigeta, Naotaka

Handbook of Geophysical Exploration; Seismic Exploration, Vol.40, p.177 - 191, 2010/03

We have developed a new electromagnetic controlled source method for the monitoring of the electrical state in the ground. This is called EM-ACROSS (Electro Magnetic - Accurately Controlled Routinely Operated Signal System). The basic idea of the EM-ACROSS system can be used at any frequency ranges. We developed one of a system using two pair of current dipoles at Tono area, and this is designed for the survey below 500 Hz, where the electromagnetic field behaves as diffusion field. We carried out a field test using this system, and acquired extremely accurate tensor transfer function from the source to the receiver, which the distance is about 950 m. From the phase of the transfer function for a month, we can see the correlation with the rainfall.

Journal Articles

Reliable measurement method to reveal a peculiar dielectric dispersion in wet rocks by means of ACROSS

Matsumoto, Hiroshi*; Shigeta, Naotaka; Kumazawa, Mineo; Nakajima, Takahiro

Handbook of Geophysical Exploration; Seismic Exploration, Vol.40, p.121 - 133, 2010/03

Journal Articles

Geophysical surveys in uranium exploration

Shigeta, Naotaka

Saishin No Butsuri Tansa Tekiyo Jireishu, p.61 - 68, 2008/10

Despite of a short history of uranium exploration, many deposits were found during just fifty years or so since the start of survey operations by making full use of geophysical surveys. For the efficient exploration considering the diversity of the deposits, it is indispensable to select an exploration flow based on establishing an appropriate model of physical properties of a uranium deposit and regional characteristics such as surface conditions. In 1990s PNC was establishing or restructuring exploration flows on unconformity-related deposits, of which type has been positioned prior to all in terms of economical merit. Deposit models and exploration flows should be revised constantly by solving various technical issues basing on the latest interpretation of obtained data. On and after 1990s, the deposit discovery rate is strikingly decreasing. This fact indicates that we are in the phase where major revises of models and exploration flows are required.

Journal Articles

Roles of geophysical exploration with regard to the geological disposal of high-level radioactive waste and development of geophysical exploration techniques in the scientific research for deep geological environments

Shigeta, Naotaka

Saishin No Butsuri Tansa Tekiyo Jireishu, p.257 - 264, 2008/10

Geological environments are required mainly two functions in terms of ensuring the safety for geological disposal of high-revel radioactive waste. One relates to long-term stabilities of a site and the other to properties of host rocks and groundwater that facilitate the emplacement and function as natural barrier. Geophysical surveys are expected to play important roles providing both implementation and safety regulation with information on deep geological environments. Japan Atomic Energy Agency, from the era of its predecessors, is carrying out studies on systematic methodology for evaluating geological environments. Useful knowledge including on geophysical survey has been obtained through the studies.

Journal Articles

Applying systematic geosynthesis methodology to surface-based investigation in "Horonobe URL Project", Japan

Hatanaka, Koichiro; Shigeta, Naotaka; Fukushima, Tatsuo

Proceedings of 2008 International High-Level Radioactive Waste Management Conference (IHLRWM 2008) (CD-ROM), p.101 - 108, 2008/09

The surface-based investigation (Phase I) in the Horonobe URL project has been conducted from March, 2001 until the end of the year 2005 as shown in Figure 1. Throughout the Phase I investigation, the concepts of geosynthesis and iterative assessment of the stepwise investigations were introduced towards characterization of the geological environment in the area including Horonobe URL site and the applicability was confirmed. The achievement of the Phase I investigation was summarized in the year 2006 and the relevant progress reports were published in March, 2007. In this paper, the concepts based on the geosynthesis methodology and its iterative application throughout stepwise investigations applied in the Horonobe URL project are discussed and summarized.

JAEA Reports

Horonobe Underground Research Laboratory project synthesis of phase I investigations 2001-2005 volume "Geoscientific Research"

Ota, Kunio; Abe, Hironobu; Yamaguchi, Takehiro; Kunimaru, Takanori; Ishii, Eiichi; Kurikami, Hiroshi; Tomura, Goji; Shibano, Kazunori; Hama, Katsuhiro; Matsui, Hiroya; et al.

JAEA-Research 2007-044, 434 Pages, 2007/03

JAEA-Research-2007-044.pdf:54.58MB
JAEA-Research-2007-044(errata).pdf:0.08MB

The Horonobe URL Project started in 2000. Research and development activities are planned over three phases, that will span a total duration of about 20 years: the 1st surface-based investigarion phase (6 years), the 2nd URL construction phase (8 years) and rhe 3rd operation phase (12 years). Geological, geophysical, geo-mechanical, hydrogeological, and hydro-geochemical investigations have been carried out during the surface-based investigation.

JAEA Reports

Development of ACROSS (Accurately Controlled, Routinely Operated, Signal System) to realize constant monitoring the invisible Earth's interiors by means of stationary coherent elastic and electromagnetic waves

Kumazawa, Mineo; Kunitomo, Takahiro; Nakajima, Takahiro; Tsuruga, Kayoko*; Hasada, Yoko*; Nagao, Hiromichi*; Matsumoto, Hiroshi*; Kasahara, Junzo*; Fujii, Naoyuki; Shigeta, Naotaka

JAEA-Research 2007-033, 155 Pages, 2007/03

JAEA-Research-2007-033.pdf:11.04MB

The developmental study made at Tono Geoscience Center under the Earthquake Frontier Research Project since 1996 is reported for a brand new technology system called ACROSS (Accurately Controlled, Routinely Operated, Signal System). Several examples of the field application are demonstrated by the test experiments at Tono Mine site. After the developmental works of 10 years, the ACROSS is brought to be a practical method applied to the remote monitoring of temporal variation of underground states at the Horonobe Underground Research Laboratory and also it is being applied to the expected focal region of the coming Tokai earthquake near Hamaoka in Shizuoka prefecture. Whereas ACROSS technology is not mature enough yet, it is shown to be a potential and versatile methodology applied even for the health monitoring of the construction such as building strongly coupled with the ground in addition to the underground study.

JAEA Reports

Study plan for performance assessment of potential effect of natural phenomena on a HLW disposal system, 5-year plan

Kawamura, Makoto; Oi, Takao; Makino, Hitoshi; Umeda, Koji; Niizato, Tadafumi; Yasue, Kenichi; Kawachi, Susumu; Ishimaru, Tsuneari; Seo, Toshihiro; Ebina, Takanori*; et al.

JAEA-Review 2006-039, 60 Pages, 2007/01

JAEA-Review-2006-039.pdf:7.39MB

This report is to outline a 5-year plan of research and development (R&D) for performance assessment of potential effect of natural phenomena on a geological disposal of high-level radioactive waste in JAEA. In each research plan, objectives based on the necessity and the significance of the research plan are clarified in the section of "Objectives and the past progresses", with summarizing the progresses of H12: Project to establish the scientific and technical basis for HLW disposal in Japan (Second Progress Report), and H17: Development and management of the technical knowledge base for the geological disposal of HLW (H17 report). In addition, next five year plan is described in the section.

Journal Articles

A Dense seismic array for acquisition of high quality in the ACROSS observation

Tsuruga, Kayoko; Kunitomo, Takahiro; Hasada, Yoko; Kumazawa, Mineo; Shigeta, Naotaka; Kasahara, Junzo

IWAM04, 116 Pages, 2004/08

We are developing an active seismic monitoring methodology on the seismic ACROSS to detect any subtle change of geophysical properties in the Earth's crust. To demonstrate the availability of the seismic ACROSS, which uses coherent seismic waves actively, it may be the best to use several dense arrays routinely. In this study, we briefly review our seismic array observation system by the seismic ACROSS and their specifications, and report the latest results of array observation.

Journal Articles

Evaluation of a dense seismic array for the acquisition of high quality data in the ACROSS observation

Tsuruga, Kayoko; Kunitomo, Takahiro; Hasada, Yoko; Kumazawa, Mineo; Shigeta, Naotaka; Kasahara, Junzo

2004 AGU Fall Meeting Program and Abstract, S31C-05, 0 Pages, 2004/00

We are developing an active monitoring methodology named ACROSS (Accurately Controlled Routinely Operated Signal System) to detect any subtle temporal change of physical properties in the Earth's interiors (Kumazawa et al., 2000). ACROSS is a comprehensive measurement system to determine continuously the transfer function of a linear system by means of the coherent signals. The combination of ACROSS transmission and array observation allow us to obtain the transfer function with high S/N (ratio of signal to noise) and S/B (ratio of signal to bias) in space and time. In this paper, we briefly review the specifications of our seismic array and report the latest results of the data analyses.

Journal Articles

Development of EM-ACROSS and observed transfer function using this system

Nakajima, Takahiro; Kunitomo, Takahiro; Nagao, Hiromichi; Kumazawa, Mineo; Shigeta, Naotaka

2004 Fall Meeting Program and Abstract, S33B-1096, 0 Pages, 2004/00

We have developed and tested a new electromagnetic sounding method, which is called EM-ACROSS (ElectroMagnetic - Accurately Controlled Routinely Operated Signal System). We carried out a field test using this system at Tono area, and acquired very accurate transfer function between the source and receiver. The estimated value of the ground conductivity is consistent with the previously reported values. From the phase of the transfer function for a month, we can see the correlation with the rainfall.

Journal Articles

Overview of EM-ACROSS

Nakajima, Takahiro; Kumazawa, Mineo; Shigeta, Naotaka; Kunitomo, Takahiro; Nagao, Hiromichi; Matsumoto, Hiroshi*

Gekkan Chikyu Gogai, (47), 174 Pages, 2004/00

We introduce a new electromagnetic sounding method called EM-ACROSS (ElectroMagnetic - Accurately Controlled Routinely Operated Signal System). The feature of the propagation of the elecromagnetic waves is defferent from that of elastic waves. We introduce the present state of the development of a systemat Tono Geoscience Center. We estimate the posivility of the exploration of deep Earth's crust.

Journal Articles

A field test of the EM-ACROSS in the frequency range of diffusion field

Nakajima, Takahiro; Kunitomo, Takahiro; Nagao, Hiromichi; Kumazawa, Mineo; Shigeta, Naotaka

Gekkan Chikyu Gogai, (47), 179 Pages, 2004/00

We have developed an electromagnetic sounding method, called EM-ACROSS (ElectroMagnetic - Accurately Controlled Routinely Operated Signal System), which can be used for the exploration of the frequency range below hundreds hertz. A trial observation has been done at Tono area for more than one year. We have obtained the accurate averaged transfer function, and also observed its temporal variation.

Journal Articles

Seismometers for ACROSS by ACROSS

Kayoko, Tsuruga; Kumazawa, Mineo; Kunitomo, Takahiro; Shigeta, Naotaka

Gekkan Chikyu Gogai, (47), 34 Pages, 2004/00

Focusing on the cover layer materials (as the Radon Barrier Materials), which could have the effect to restrain the radon from scattering into the air and the effect of the radiation shielding, we produced the radon barrier materials with crude bentonite on an experimental basis, using the rotary type comprehensive unit for grinding and mixing, through which we carried out the evaluation of the characteristics thereof.

Journal Articles

A Dense Seismic Array for Acquisition of High Quality Data in ACROSS Observation

Tsuruga, Kayoko; Kunitomo, Takahiro; Hasada, Yoko; Kumazawa, Mineo; Shigeta, Naotaka;

Gekkan Chikyu Gogai, (47), 95 Pages, 2004/00

There is a problem of vibration in a diagnosis system of helical evaporator tubes installed in a nuclear power station. Numerical simulations are implemented on the assumption that the vibration is caused by the Coulomb's friction. An analytical model is derived as a large scale nonlinear vibration system and a lot of computational cost would be required to carry out the simulations. The Transfer Influence Coefficient Method, which has high accuracy and efficiency in numerical computations, is applied and efficiently implements the simulations. The vibrations are qualitatively reproduced by the simulations. It enables us to make a pre-evaluation of several means to suppress the vibrations are qualitatively reproduced by the simulations. It enables us to make a pre-evaluation of several means to suppreess the vibration and the most effective devise is expected through the simulation.

Journal Articles

Long-Term Operation of EM-ACROSS and Derived Transfer Function in the Diffusion Field Region

Nakajima, Takahiro; Kunitomo, Takahiro; Nagao, Hiromichi; Kumazawa, Mineo; Shigeta, Naotaka

International Workshop on Active Monitorig 2004, p.148 - 151, 2004/00

We have developed and tested a new electromagnetic sounding method, which is called EM-ACROSS (ElectroMagnetic - Accurately Controlled Routinely Operated Signal System). This system is designed for the survey below 500Hz. We carried out a field test using this system at Tono area, and acquired very accurate transfer function between the source and receiver which the distance is about 700m. From the phase of the transfer function for a month, we can see the correlation with the rainfall.

Journal Articles

Overview of EM-ACROSS and its development

Nakajima, Takahiro; Kumazawa, Mineo; Shigeta, Naotaka; Kunitomo, Takahiro; Nagao, Hiromichi; Matsumoto, Hiroshi*

International Workshop on Active Monitoring 2004, p.100 - 103, 2004/00

We introduce a new observation system named EM-ACROSS (Electro-Magnetic Accurately Controlled Routinely Operated Signal System) for a monitoring the electrical state in the ground. Electromagnetic field has different feature from seismic wave, in a sense that electromagnetic field behaves not only as waves but also diffusion. We describe the overview of EM-ACROSS and the progress of its development at Tono Geoscience Center. We also note the possibility of the active monitoring of the crust using electromagnetic field.

Journal Articles

Underground research laboratories in Japan; What are the important factors for facilities design?

Sato, Toshinori; Mikake, Shinichiro; Sakamaki, Masanori; Aoki, Kazuhiro; Yamasaki, 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.

Journal Articles

Study of Dielectric Dispersion in Moist Rocks at Low Frequency as a Possible Clue for Sounding of H2O in the Earth's Crust

Matsumoto, Hiroshi; Matsumoto, Hiroshi; Shigeta, Naotaka; Kumazawa, Mineo; Nakajima, Takahiro

American Geophysical Union (AGU) 2003 Fall Meeting, F525, 0 Pages, 2003/00

None

37 (Records 1-20 displayed on this page)