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Journal Articles

Estimation of kinematic and stress history by composite planar fabric and stress inversion analysis: Application to the Shionohira and Kuruma Faults

Sakai, Toru*; Kametaka, Masao*; Aoki, Kazuhiro; Shimada, Koji; Takagi, Hideo*

Chishitsugaku Zasshi (Internet), 130(1), p.89 - 109, 2024/04

Shear planes are formed in various orientations within fault fracture zones. The sense of shear on each shear plane can be determined from the composite planar fabrics developed around it. However, it is not possible to distinguish whether all the shear planes in a fault fracture zone were formed during the same stage of motion by observations alone, because of the scarcity of chronological data. As such, we attempted to determine the kinematic and stress histories of the Shionohira and Kuruma faults by using both observations of composite planar fabrics and stress inversion analysis. As a result, we identified five stages of motion on the Shionohira Fault and two stages of motion on the Kuruma Fault. The chronological data are not sufficient to constrain the timing of the stages, but the reconstructed histories are consistent with the paleostress fields and tectonic activity around these faults, as determined in previous studies. Although the reconstructed stress history depends on the density of fault-slip data from the measurement area, this method is effective for investigating the formation mechanisms of fault fracture zones.

Journal Articles

High peak-current lightning discharges associated with downward terrestrial gamma-ray flashes

Wada, Yuki*; Enoto, Teruaki*; Nakamura, Yoshitaka*; Morimoto, Takeshi*; Sato, Mitsuteru*; Ushio, Tomoo*; Nakazawa, Kazuhiro*; Yuasa, Takayuki*; Yonetoku, Daisuke*; Sawano, Tatsuya*; et al.

Journal of Geophysical Research; Atmospheres, 125(4), p.e2019JD031730_1 - e2019JD031730_11, 2020/02

 Times Cited Count:21 Percentile:80.58(Meteorology & Atmospheric Sciences)

Journal Articles

Gamma-ray glow preceding downward terrestrial gamma-ray flash

Wada, Yuki*; Enoto, Teruaki*; Nakamura, Yoshitaka*; Furuta, Yoshihiro; Yuasa, Takayuki*; Nakazawa, Kazuhiro*; Morimoto, Takeshi*; Sato, Mitsuteru*; Matsumoto, Takahiro*; Yonetoku, Daisuke*; et al.

Communications Physics (Internet), 2(1), p.67_1 - 67_9, 2019/06

 Times Cited Count:49 Percentile:93.08(Physics, Multidisciplinary)

JAEA Reports

Study on evaluation methodology for groundwater flow based on geochemical data, 2; Case study for Horonobe area (Contract research)

Sakai, Ryutaro; Takeda, Seiji; Munakata, Masahiro; Kimura, Hideo

JAEA-Research 2013-006, 18 Pages, 2013/07

JAEA-Research-2013-006.pdf:2.77MB

In the safety assessment for a geological disposal of radioactive waste, it is important to establish validation methods for deep groundwater flow to estimate radionuclide migration to human environment through groundwater flow. Costal sedimentary rocks in our country provide dominant fossil water formed during sub-seabed sedimentation and chemical compositions of the water mixed with meteoric water and fossil water depend on the initial fossil water composition and groundwater flow conditions. Analytical study on the effects of groundwater flow on the mixed water quality as a indicator of its Cl/$$delta$$$$^{18}$$O ratios was carried out in case of Horonobe district, where geochemical data is now being stored.

Journal Articles

Trial fabrication of one-third scale double pancake of ITER toroidal field coil

Matsui, Kunihiro; Koizumi, Norikiyo; Hemmi, Tsutomu; Takano, Katsutoshi; Nakajima, Hideo; Kimura, Satoshi*; Iijima, Ami*; Sakai, Masahiro*; Osemochi, Koichi*; Shimada, Mamoru*

IEEE Transactions on Applied Superconductivity, 22(3), p.4203005_1 - 4203005_5, 2012/06

 Times Cited Count:6 Percentile:37.82(Engineering, Electrical & Electronic)

JAEA is responsible for the procurement of 9 toroidal field (TF) coils as Japanese Domestic Agency. JAEA had started several trials to successfully develop technologies for the TF coil manufacture since March 2009, and performed one-third scale trials aiming at qualifying and optimizing the procedures of the TF coil fabrication. The fabricated double pancakes (DPs) were successfully put into the profile with tolerances from zero to 1.5 mm. These tolerances correspond to 0.06% accuracy in the conductor length. The geometry of the DP was changed after heat treatment. Heat treatment procedure to avoid such deformation should be developed or the change of winding geometry should be taken into account in the fabrication of the TF coils. The one-third scale DP was successfully impregnated. Although exothermal reaction is given to take place during curing in the blended resin, we successfully cured the one-third scale DP.

JAEA Reports

Study on evaluation methodology for groundwater flow based on geochemical data; Case study for Horonobe area (Contract research)

Sakai, Ryutaro; Munakata, Masahiro; Kimura, Hideo

JAEA-Research 2011-054, 19 Pages, 2012/03

JAEA-Research-2011-054.pdf:2.07MB

In the safety assessment for a geological disposal of radioactive waste, it is important to establish validation methods for deep groundwater flow system to estimate radionuclide migration to human environment through groundwater flow. This study discussed the method which estimates groundwater mixing condition and groundwater flow process using principal component analysis (PCA) to groundwater chemistry and isotopic compositions, together with data of groundwater age and trace element in case of Horonobe area. The results show that hydrochemical system can be divided into two systems: (1) three deep groundwater mixing system at depths greater than 200 to 400 m, (2) mixing area of deep groundwater and surface water at depths less than 200 to 400 m. Groundwater in the deep aquifer is suggested to be discharged at surface through Omagari Fault.

Journal Articles

Insulation and impregnation test for ITER toroidal field coils

Hemmi, Tsutomu; Matsui, Kunihiro; Koizumi, Norikiyo; Nakajima, Hideo; Iijima, Ami*; Sakai, Masahiro*

Teion Kogaku, 47(3), p.172 - 177, 2012/03

The manufacturing process for the ITER Toroidal Field (TF) coil has to be demonstrated for the qualification. Since the impregnation of its insulation system is one of the qualifications, the authors performed impregnation test using cyanate-ester and epoxy blended resin, which is a candidate among resins because of its excellent resistance to radiation. To establish the insulation and impregnation procedure of the TF coil manufacturing, three types of trials were performed. (1) Impregnation tests using an acrylic model to fix the impregnation conditions; (2) Impregnation test using a metallic model to confirm that no void remains in the insulation layer after the curing in the D-shaped configuration; and (3) Insulation and impregnation trials using 1/3 scale double pancake (DP) to establish the insulation and impregnation procedure for the TF coil manufacturing, The procedure of the insulation and impregnation for the ITER TF coil was established from the results of these trials.

JAEA Reports

Study on validation method of regional groundwater flow model; Case study for Horonobe area and Niigata basin (Contract research)

Sakai, Ryutaro; Munakata, Masahiro; Kimura, Hideo; Ooka, Masao*; Seguchi, Mariko*

JAEA-Research 2011-029, 24 Pages, 2011/11

JAEA-Research-2011-029.pdf:3.67MB

In the safety assessment for a geological disposal of radioactive waste, it is important to establish validation methods for regional groundwater flow system to estimate radionuclide migration to human environment through groundwater flow. It is necessary to validate the groundwater flow property and flow boundary, as multi-groundwater systems including the different groundwater origins are possible to exist at deep underground. This results show that mixing analysis based on hydrochemical data and spatial plotting with hydrochemical data and thermal data are applicable to validate groundwater flow pattern and groundwater flow boundary in case of Horonobe area. It also demonstrates that mixing analysis based on hydrochemical data and spatial plotting with hydrological and hydrochemical data are applicable to validate the groundwater flow property and groundwater flow boundary in case of Nagaoka area.

JAEA Reports

Technical report on the project for improving the JAEA's enterprise resource planning system

Kimura, Hideo; Aoyagi, Tetsuo; Sato, Taiichi; Sakai, Manabu; Hikasa, Naoki*; Suzuki, Hitoshi; Tsuji, Minoru

JAEA-Technology 2011-027, 31 Pages, 2011/09

JAEA-Technology-2011-027.pdf:2.16MB

The financial accounting and contract management system of JAEA, built on a commercial ERP package, had suffered from serious problems of high lifecycle cost, poor response, and lack of extensibility, due to the too much customization to the ERP package, and disorganized software structure. To solve those problems, three approaches were applied; (1) conducting thorough analysis of business flow and fit/gap, which enabled removing all customization brought to the ERP package; (2) dividing the system into subsystems, and clearly defining interfaces between the subsystems, which increases the transparency, extensibility and performance of the system; (3) outsourcing the development of the subsystems to multiple venders to reduce the development cost. Those approaches can be useful for developing business information systems using commercial software to save time and cost, while meeting the unique requirements of an organization.

JAEA Reports

Development of FEP database for geological and climatic disruptive events; Uplift, subsidence, earthquake activity, and climate change (Contract research)

Sakai, Ryutaro; Takeda, Seiji; Kimura, Hideo; Matsuba, Hisashi*

JAEA-Data/Code 2011-005, 107 Pages, 2011/06

JAEA-Data-Code-2011-005.pdf:2.74MB

In the safety assessment for a geological disposal of radioactive waste such as high-level radioactive waste, it is necessary to estimate the hydrological environmental changes affected by external factors such as long-termed earthquake activity and volcanic activity. Therefore it is important to perform the informations including a wide range of future processes and conditions of engineered barriers and geosphere in a systematic manner and to construct scenarios considering external factors. Generation of geological and climatic disruptive events such as earthquake activity, volcanic activity, uplift, subsidence, climatic change and sea-level change and propagation process of their impacts and their types are needed to be clarified in order to understand the phenomena of their influence on a disposal system in case of our country. Japan Atomic Energy Agency started to develop FEP database including the correlation of FEPs and FEP data sheet.

Journal Articles

Recharge evaluation of northern area in Hokkaido, Japan

Ikeda, Makoto; Munakata, Masahiro; Sakai, Ryutaro; Kimura, Hideo; Jia, H.*; Matsuba, Hisashi*

Nihon Chikasui Gakkai 2011-Nen Shunki Koenkai Koen Yoshi, p.86 - 91, 2011/05

no abstracts in English

JAEA Reports

Study on validation method of regional groundwater flow model; Case study for Boso peninsula

Sakai, Ryutaro; Munakata, Masahiro; Kimura, Hideo; Ichikawa, Yasuo*; Nakamura, Masaru*

JAEA-Research 2010-066, 20 Pages, 2011/03

JAEA-Research-2010-066.pdf:2.26MB

In the safety assessment for a geological disposal of radioactive waste, it is important to establish modelling methods and validation methods for regional groundwater flow system in the depth of 300$$sim$$1000m to estimate radionuclide migration to human environment through groundwater flow system. The study discussed application of data and assessment methods for model validation based on multiple indicators such as hydrology, groundwater chemistry, temperature and age of groundwater in case of the Boso Peninsula in Chiba Prefecture where a lot of in-situ data about groundwater was measured. This results show that existing hydrochemical and thermal data are applicable to explain freshwater and saltwater distribution and groundwater flow pattern in case of regional scale. It also indicates that gravitational groundwater is likely to flow into the deep part of fresh-saltwater interface based on the exist of Na-HCO$$_{3}$$ type water above fresh-saltwater interface mixed with meteoric water and that multiple indicators are applicable to evaluate groundwater flow property and groundwater flow boundary in case of site scale region.

Journal Articles

Study of influence factors on hydraulic conductivity of sedimentary rocks

Sakai, Ryutaro; Munakata, Masahiro; Kimura, Hideo; Ooka, Masao*; Kameya, Hiroshi*; Hosoda, Koichi*

Dai-21-Kai Zenkoku Chishitsu Chosagyo Kyokai Rengokai "Gijutsu Foramu" Koenshu (CD-ROM), 2 Pages, 2010/11

no abstracts in English

Journal Articles

Recharge evaluation using distributed tank model

Ikeda, Makoto; Munakata, Masahiro; Sakai, Ryutaro; Fuchiwaki, Hirotaka; Kimura, Hideo; Matsuba, Hisashi*

Nihon Chikasui Gakkai 2010-Nen Shuki Koenkai Koen Yoshi, p.282 - 287, 2010/11

no abstracts in English

Journal Articles

Methodological studies for evaluation of groundwater flow system in a sedimentary rock area; Case study for the Boso Peninsula

Sakai, Ryutaro; Munakata, Masahiro; Kimura, Hideo

Chikasui Gakkai-Shi, 51(4), p.311 - 329, 2009/11

In order to evaluate the regional groundwater flow system, the author has investigated stream flow of 3 rivers and analyzed flow rates and chemical compositions, isotopic ratios of hydrogen and oxygen of water samples collected from wells, rivers and springs in the feeder streams area in the Yoro river basin, in Chiba Prefecture. As a result of this study, (Na)Ca-HCO$$_{3}$$ type water is evaluated to be recharged from the highly permeable sand-dominant domain (Daifuku Mt.). In addition, it is estimated that the groundwater flow preferentially in direction of strike and discharge at the middle and downstream domain as Ca-HCO$$_{3}$$ type water, and partially pass through fractures of low permeable alteration layer up to the surface area as evolved Na-HCO$$_{3}$$ type water.

JAEA Reports

Study on assessment scenarios of natural phenomena effected on groundwater flow system; Case study for the sea-level change (Contract research)

Sakai, Ryutaro; Munakata, Masahiro; Kimura, Hideo

JAEA-Research 2008-122, 18 Pages, 2009/03

JAEA-Research-2008-122.pdf:6.57MB

It is important to evaluate effect on the groundwater flow system by the natural phenomena in the safety assessment of geological disposal of radioactive waste through a survey of recent scientific informations. In this report we study about the scenario of sea level change effecting on the groundwater flow system which is very important for a safety of disposal facility in costal area. As a result, this study show that the non-current paleo-fresh water at present is possible to start to discharge at sea floor in the next glacial period by denudation of marine-clay sediments and to grow stagnant again in the next interglacial period by deposition of marine-clay sediments. Therefore it is important to predict the scenario considering the denudation and deposition correlated with transgression and regression that could affect the change of groundwater flow characteristics during the glacial and interglacial period.

JAEA Reports

Conceptual design for the next JAEA's enterprise resource planning system

Kimura, Hideo; Aoyagi, Tetsuo; Sakai, Manabu; Sato, Taiichi; Tsuji, Minoru

JAEA-Technology 2008-075, 32 Pages, 2008/11

JAEA-Technology-2008-075.pdf:8.29MB

JAEA developed the ERP (Enterprise Resource Planning) system at the establishment in 2005, aiming to support and enhance its business-critical task such as financial accounting and contract management. We considered the conceptual design of the next ERP system, and we implemented the prototype system to validate its effectiveness. Moreover, we implemented the simple add-on tool for rapid and easy development. At the result, we gauged the future prospects that the XML-centric system which we designed will offer high modularity, flexibility, connectivity between other systems, independence among subsystems. The simple add-on tool also demonstrated its effectiveness.

JAEA Reports

Study on groundwater flow system in a sedimentary rock area, 2; Case study for the Yoro River basin, Chiba prefecture

Sakai, Ryutaro; Munakata, Masahiro; Kimura, Hideo

JAEA-Research 2007-083, 38 Pages, 2008/01

JAEA-Research-2007-083.pdf:3.29MB

Japan Atomic Energy Agency has investigated a sedimentary rock area in the central part of Yoro river basin, in Chiba Prefecture for verification of analytical groundwater flow model. For the purpose of establishing a methodology for evaluation of regional groundwater flow system, investigations of flow rates, chemical compositions and isotope ratios for water samples collected from wells, rivers and springs were carried out. As a result, considerable amount of ground water which is NaCa-HCO$$_{3}$$ type or evolved Ca-HCO$$_{3}$$ type meteoric origin cultivated at the high permeable sand dominant layer preferentially flows toward its strike direction discharging at the downstream region of river. The evolved Ca-HCO$$_{3}$$ type or Na-HCO$$_{3}$$ type ground water with long residence time was inferred to form different flowpath toward the dipping direction of bedrock more than 100m at depth and to upwell to the downstream region of Urajiro River as a feeder of Yoro River through the low permeable mud layer.

JAEA Reports

Study on groundwater flow system in a sedimentary rock area; Case study for the Yoro river basin, Chiba Prefecture

Sakai, Ryutaro; Munakata, Masahiro; Kimura, Hideo

JAEA-Research 2006-084, 16 Pages, 2007/01

JAEA-Research-2006-084.pdf:1.74MB

Japan Atomic Energy Agency (JAEA) has started to investigate a sedimentary rock area in the Yoro river basin, in Chiba Prefecture. Hydro-chemical conditions of the regional groundwater were discussed based on temperature, chemical compositions, isotopic ratios of hydrogen and oxygen, and the isotopic age of radioactive carbon for water samples collected from wells, rivers and springs in the Yoro river basin. It was found that the groundwater system in this basin consists of types of water: Ca-HCO$$_{3}$$ type water, Na-HCO$$_{3}$$ type water and NaCl type water. The Ca-HCO$$_{3}$$ type water is meteoric water cultivated several thousand years or after, the Na-HCO$$_{3}$$ type water is meteoric water cultivated under cold climates several to twenty thousand years ago. The NaCl type water is fossil brine water formed twenty thousand years ago. It was also observed that the Na-HCO$$_{3}$$ type water upwelled at the surface originates from GL-200m to -400m.

JAEA Reports

Bioinformatics; Date base and application execution Web system

Kimura, Hideo; Sakai, Tomo*

JAERI-Data/Code 2004-001, 32 Pages, 2004/03

JAERI-Data-Code-2004-001.pdf:1.34MB

no abstracts in English

43 (Records 1-20 displayed on this page)