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Journal Articles

Tunnel excavation analysis of siliceous mudstone using a damage model

Mishima, Seiki*; Ogata, Sho*; Inui, Toru*; Yasuhara, Hideaki*; Kishida, Kiyoshi*; Aoyagi, Kazuhei

Dai-15-Kai Iwa No Rikigaku Kokunai Shimpojiumu Koen Rombunshu (Internet), p.215 - 220, 2021/01

When the durability of the geological repository of high-level radioactive waste is evaluated, understanding the cracking behavior within the crystalline/sedimentary rocks during excavation of waste disposal cavities is important. In this study, we performed a numerical analysis that expressed the tunnel excavation carried out 350 m underground at the Horonobe Underground Research Center of the Japan Atomic Energy Agency. Simulated results are agreement with actual trends of fracture propagation, and the measured horizontal convergence of the tunnel was reproduced by the numerical analysis relatively well.

Journal Articles

Coupled THMC analysis for predicting hydro-mechanical evolution in siliceous mudstone

Ogata, Sho*; Yasuhara, Hideaki*; Aoyagi, Kazuhei; Kishida, Kiyoshi*

Proceedings of 53rd US Rock Mechanics/Geomechanics Symposium (USB Flash Drive), 6 Pages, 2019/06

Journal Articles

Segmentation of granite and single fracture through microfocus X-ray CT and its application

Ishikawa, Tomohiro*; Yasuhara, Hideaki*; Sawada, Atsushi; Kishida, Kiyoshi*

Dai-50-Kai Jiban Kogaku Kenkyu Happyokai Rombunshu, p.515 - 516, 2015/06

no abstracts in English

Journal Articles

Measurements of fracture aperture in granite core using microfocus X-ray CT and fluid flow simulation

Kishida, Kiyoshi*; Ishikawa, Tomohiro*; Higo, Yosuke*; Sawada, Atsushi; Yasuhara, Hideaki*

Proceedings of 49th US Rock Mechanics/Geomechanics Symposium (CD-ROM), 6 Pages, 2015/06

In order to estimate the changes in fracture aperture under various long-term confining and thermal conditions, measurements of the fracture aperture are conducted using microfocus X-ray CT. Through the imaging data, the altitude of the fracture surface and the contact points are evaluated, and contact ratios for the fracture, the JRC and the aperture distribution are estimated. On the other hand, measurements are also conducted using a laser scan profile sensor, and some parameters are estimated. In comparing these parameters, the validity of the X-ray CT data and an analysis of the data will be discussed. In addition, a fracture flow simulation will be conducted using the altitude and aperture data obtained by the microfocus X-ray CT.

JAEA Reports

Enhancement of the methodology of repository design and post-closure performance assessment for preliminary investigation stage, 2; Progress report on NUMO-JAEA collaborative research in FY2012 (Joint research)

Shibata, Masahiro; Sawada, Atsushi; Tachi, Yukio; Hayano, Akira; Makino, Hitoshi; Wakasugi, Keiichiro; Mitsui, Seiichiro; Oda, Chie; Kitamura, Akira; Osawa, Hideaki; et al.

JAEA-Research 2013-037, 455 Pages, 2013/12

JAEA-Research-2013-037.pdf:42.0MB

Following FY2011, JAEA and NUMO have conducted a collaborative research work which is designed to enhance the methodology of repository design and performance assessment in preliminary investigation stage. With regard to (1) study on rock suitability in terms of hydrology, the tree diagram of methodology of groundwater travel time has been extended for crystalline rock, in addition, tree diagram for sedimentary rock newly has been organized. With regard to (2) study on scenario development, the existing approach has been improved in terms of a practical task, and applied and tested for near field focusing on the buffer. In addition, the uncertainty of some important processes and its impact on safety functions are discussed though analysis. With regard to (3) study on setting radionuclide migration parameters, the approaches for parameter setting have been developed for sorption for rocks and solubility, and applied and tested through parameter setting exercises for key radionuclides.

Journal Articles

Estimation of fracture flow in considering the inhomogeneous structure of single rock fractures

Kishida, Kiyoshi*; Sawada, Atsushi; Yasuhara, Hideaki*; Hosoda, Takashi*

Soils and Foundations, 53(1), p.105 - 116, 2013/02

 Times Cited Count:17 Percentile:65.57(Engineering, Geological)

Considering the safe, long-term sequestration of energy byproducts, such as radioactive waste, one of the important parameters is the groundwater flow velocity through the void of rock masses and/or fractures. In this research work, two-dimensional seepage flow analyses, using the authors' proposed 2D model, with considering the inertia term, are carried out for single fracture permeability tests under conditions which allow for the application of the cubic law. In comparing the results of the experiments with the numerical simulations, the results of the simulation show a good agreement with the experimental results. From these simulation results, the fracture flow of an inhomogeneous structure is discussed, along with the local Reynolds number, and the resistance through the fracture geometry is considered. Consequently, under the condition of a mean Reynolds number of less than 1.0, the inertia terms cannot affect on the fracture flow, but the hydraulic resistance can affect.

JAEA Reports

Enhancement of the methodology of repository design and post-closure performance assessment for preliminary investigation stage; Progress report on NUMO-JAEA collaborative research in FY2011 (Joint research)

Shibata, Masahiro; Sawada, Atsushi; Tachi, Yukio; Makino, Hitoshi; Hayano, Akira; Mitsui, Seiichiro; Taniguchi, Naoki; Oda, Chie; Kitamura, Akira; Osawa, Hideaki; et al.

JAEA-Research 2012-032, 298 Pages, 2012/09

JAEA-Research-2012-032.pdf:33.68MB

JAEA and NUMO have conducted a collaborative research work which is designed to enhance the methodology of repository design and performance assessment in preliminary investigation phase. The topics and the conducted research are follows; (1) Study on selection of host rock: in terms of hydraulic properties, items for assessing rock property, and assessment methodology of groundwater travel time has been organized with interaction from site investigation. (2) Study on development of scenario: the existing approach has been embodied, in addition, the phenomenological understanding regarding dissolution of and nuclide release from vitrified waste, corrosion of the overpack, long-term performance of the buffer are summarized. (3) Study on setting nuclide migration parameters: the approach for parameter setting has been improved for sorption and diffusion coefficient of buffer/rock, and applied and tested for parameter setting of key radionuclides. (4) Study on ensuring quality of knowledge: framework for ensuring quality of knowledge has been studied and examined aimed at the likely disposal facility condition.

Journal Articles

Dependence of fracture geometry and spatial variation in pressure on hydraulic conductivity in rock fractures

Kishida, Kiyoshi*; Hosoda, Takashi*; Sawada, Atsushi; Sato, Hisashi; Nakashima, Shinichiro*; Yasuhara, Hideaki*

Harmonising Rock Engineering and the Environment, p.1327 - 1330, 2011/10

Although it is generally known that a natural rock fracture indicates a complex aperture distribution, the fracture is an ideal representation of the parallel plate model. The cubic law is applied to evaluate the hydraulic properties of fractured rock. From several previous research works, it is known that the cubic law can be applied when the Reynolds number is less than 1.0 and that the advection term can basically be ignored in such fracture flows. In this research work, two-dimensional seepage flow analyses, using the authors' proposed 2D model which is considered with the advection term, are carried out for single fracture hydro-conductivity experiments under conditions which allow for the application of the cubic law. From the numerical results, the validity of the 2D model is discussed along with the local Reynolds number and the application of the cubic law.

JAEA Reports

Measurement of corrosion products (CP) deposition in the experimental fast reactor Joyo; CP deposition distribution after MK-III modifications

Ito, Chikara; Ito, Hideaki; Ishida, Koichi; Aoyama, Takafumi

JAEA-Technology 2011-007, 56 Pages, 2011/06

JAEA-Technology-2011-007.pdf:9.2MB

In the experimental fast reactor Joyo, measurement for characterizing and predicting the deposition condition and the condition change of the corrosion product (CP) that is the major radiation source in equipments and piping of primary cooling system has been carried out regularly from early period of reactor operation. Cooling system modification work with the shift to the MK-III core was carried out after the last measurement that was carried out, and the main equipments such as intermediate heat exchangers were replaced. This measurement in this report was carried out at after the 2nd cycle operation of the MK-III core which started formal operation.

JAEA Reports

Study on Geology on Mizunami Underground Research Laboratory Project; Annual report for fiscal year 2008

Tsuruta, Tadahiko; Matsuoka, Toshiyuki; Hodotsuka, Yasuyuki; Tagami, Masahiko; Ishida, Hideaki; Hayano, Akira; Kurihara, Arata; Yuguchi, Takashi

JAEA-Research 2010-039, 131 Pages, 2011/01

JAEA-Research-2010-039.pdf:25.36MB

Tono Geoscientific Unit of Geological Isolation and Development Directoratte is performing Mizunami Underground Research Laboratory (MIU) Project, which is a broad scientific study of the deep geological environment as a basis of research and development for geological disposal of nuclear wastes, in order to establish comprehensive techniques for the investigation, analysis and assessment of the deep geological environment in fractured crystalline rock. The MIU Project has three overlapping 3 phases, with a total duration of 20 years. The project goals of the MIU Project from Phase I through to Phase III are: to establish techniques for investigation, analysis and assessment of the deep geological environment, and to develop a range of engineering for deep underground application. Currently, the project is under the Phase II. This document presents the overview of results of the research and development on "geology" performed in fiscal year 2008, with regard to the Phase II goal.

Journal Articles

The Project for grouting development for high level radioactive waste repository, 4; Development of superfine spherical silica grout

Yamada, Tsutomu*; Sekine, Ichiro*; Sekiguchi, Takashi*; Ishida, Hideaki*; Kishi, Hirokazu; Fukuoka, Naomi

Doboku Gakkai Heisei-22-Nendo Zenkoku Taikai Dai-65-Kai Nenji Gakujutsu Koenkai Koen Gaiyoshu (DVD-ROM), p.89 - 90, 2010/09

no abstracts in English

JAEA Reports

Studies on planning and conducting for reducing water inflow due to underground construction in crystalline rock

Mikake, Shinichiro; Yamamoto, Masaru; Ikeda, Koki; Sugihara, Kozo; Takeuchi, Shinji; Hayano, Akira; Sato, Toshinori; Takeda, Shinichi; Ishii, Yoji; Ishida, Hideaki; et al.

JAEA-Technology 2010-026, 146 Pages, 2010/08

JAEA-Technology-2010-026.pdf:41.08MB
JAEA-Technology-2010-026-appendix(CD-ROM).zip:83.37MB

The Mizunami Underground Research Laboratory (MIU), one of the main facilities in Japan for research and development of the technology for high-level radioactive waste disposal, is under construction in Mizunami City. In planning the construction, it was necessary to get reliable information on the bedrock conditions, specifically the rock mass stability and hydrogeology. Therefore, borehole investigations were conducted before excavations started. The results indicated that large water inflow could be expected during the excavation around the Ventilation Shaft at GL-200m and GL-300m Access/Research Gallery. In order to reduce water inflow, pre-excavation grouting was conducted before excavation of shafts and research tunnels. Grouting is the injection of material such as cement into a rock mass to stabilize and seal the rock. This report describes the knowledge and lessons learned during the planning and conducting of pre-excavation grouting.

Journal Articles

Development of superfine spherical silica grout as an alternative grouting material for the geological disposal of long-lived radioactive waste

Naito, Morimasa; Kishi, Hirokazu; Fukuoka, Naomi; Yamada, Tsutomu*; Ishida, Hideaki*

Proceedings of 18th International Conference on Nuclear Engineering (ICONE-18) (CD-ROM), 7 Pages, 2010/05

As an alternative grouting material for the geological repository of long-lived radioactive waste, the "Superfine Spherical silica Grout" (SFSG) material is developed using a fine spherical silica and a fine calcium hydroxide. The developed SFSG material takes an advantage of its smaller particle size distribution (max. $$sim$$1 micron or less) than those of the cementitious materials, and also provides a low alkaline environment so as to reduce unfavorable effects on the long-term performance of geological disposal system. The SFSG is a mixture of the super fine silica powder, the superfine calcium hydroxide and additives such as superplasticizer. Some preliminary laboratory experiments were carried out to characterize its fundamental properties from the viewpoint of practical use for geological disposal, which is required to be equivalent with the conventional cementitious materials in terms of penetrability, strength, pH performance and workability.

Journal Articles

Applicability of countermeasure for reduction of groundwater inflow and construction of the Mizunami Underground Research Laboratory

Mikake, Shinichiro; Yamamoto, Masaru; Ikeda, Koki; Ishida, Hideaki; Nishigaki, Makoto*

Dai-54-Kai Jiban Kogaku Shimpojiumu Rombunshu, p.39 - 46, 2009/11

The Mizunami Underground Research Laboratory (MIU) is currently being constructed. During its construction, water inflow into the shafts of the MIU has been increasing and affecting the project progress. In order to reduce the water inflow into the shafts, borehole investigations and pre-excavation grouting have been conducted. The pre-excavation grouting has been undertaken at the predicted inflow area with existing method.

Journal Articles

Characteristics of high angle fractures distributed in granite of MIU (Mizunami Underground Research Laboratory)

Tagami, Masahiko; Ishida, Hideaki; Tsuruta, Tadahiko

Nihon Oyo Chishitsu Gakkai Heisei-21-Nendo Kenkyu Happyokai Koen Rombunshu, p.175 - 176, 2009/10

Fractures in crystalline rocks have exerted a big influence on the underground water stream. It is necessary to understand the fracture shape and distribution from the viewpoint of the material transfer and the safety construction in designing the geological disposal facilities of the high-level nuclear waste. In this report, we examined the fracture characteristics along the horizontal tunnel which was named -300m Access/Research gallery in Mizunami Underground Research Laboratory. Spring water that exceeded 1000 liters per minute was confirmed in the horizontal boring investigation along the tunnel before gallery excavation. We considered the fracture formation process and the function as the passage of water.

Journal Articles

Introduction to plasma fusion energy

Takamura, Shuichi*; Kado, Shinichiro*; Fujii, Takashi*; Fujiyama, Hiroshi*; Takabe, Hideaki*; Adachi, Kazuo*; Morimiya, Osamu*; Fujimori, Naoji*; Watanabe, Takayuki*; Hayashi, Yasuaki*; et al.

Kara Zukai, Purazuma Enerugi No Subete, P. 164, 2007/03

no abstracts in English

Journal Articles

Evolution of permeability in diatomaceous rocks mediated by pressure solution

Yasuhara, Hideaki*; Kurikami, Hiroshi; Kinoshita, Naoki*; Kishida, Kiyoshi*

Dai-36-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koen Rombunshu, p.283 - 286, 2007/01

no abstracts in English

Journal Articles

Electroplating of the superconductive boride MgB$$_{2}$$ from molten salts

Abe, Hideki*; Yoshii, Kenji; Nishida, Kenji*; Imai, Motoharu*; Kitazawa, Hideaki*

Journal of Physics and Chemistry of Solids, 66(2-4), p.406 - 409, 2005/04

 Times Cited Count:7 Percentile:35.17(Chemistry, Multidisciplinary)

An electroplating technique of the superconductive boride MgB$$_{2}$$ onto graphite substrates is reported. Films of MgB$$_{2}$$ with a thickness of tens micrometer were fabricated on the planar and curved surfaces of graphite substrates by means of electrolysis on a mixture of magnesium chloride, potassium chloride, sodium chloride, and magnesium borate fused at high temperatures in an Ar atmosphere. The electrical resistivity and magnetization measurements revealed that the electroplated MgB$$_{2}$$ films undergo a superconducting transition with the critical temperature of 36 K.

JAEA Reports

Fuel Failure Simulation Test in JOYO; FFDL in-pile test(III)

Ito, Chikara; Ito, Hideaki; Ishida, Koichi; Hatoori, Kazuhiro; Oyama, Kazuhiro; Sukegawa, Kazuya*; Murakami, Takanori; Kaito, Yasuaki; Nishino, Kazunari; Aoyama, Takafumi; et al.

JNC TN9410 2005-003, 165 Pages, 2005/03

JNC-TN9410-2005-003.pdf:12.66MB

At experimental fast reactor JOYO, appraisal of detection efficiency of behavior and FFD and FFDL of the fission product which is discharged inside the furnace as one of safety research of the country, is carried out. In MK-II core, the slit in the gas plenum part of the test sub-assembly, the test which irradiates this(1985 April, FFDL in-pile test(I)), providing the slit in the fuel column part of the test sub-assembly, the test which it irradiates(1992 November, FFDL in-pile test(II)) were carried out.MK-III reactor core replacement was completed and started in 2004. That the behavior in the system of FP with the reactor core replacement and so on changes in the MK-III reactor core and to have an influence on the sensitivity and the replying of FFD and FFDL are thought of. Therefore, behavior of FP in the fuel failure in the MK-III reactor core, the performance of FFD and FFDL must be confirmed beforehand. Moreover, to prepare for the fuel failure and the RTCB test which is doing a future plan, and to confirm a plant operation procedure in the fuel failure in MK-III reactor core operation and to attempt for the correspondency to improve are important.Therefore, in the period from 2004 November 11th to November 29th, it carried out the FFDL in-pile(III). It did a series of plant operation to stop a nuclear reactor after loading a reactor core center with the fuel element for the test which provided an artificial slit for the fuel cladding in the MK-III reactor core and irradiating it and detecting fuel damaging and to take out fuel. And it confirmed the operation procedure of the fast reactor in the fuel failure.Also, the improvement items such as the improvement of the operation and the procedure and the remodeling and the service of the facilities could be picked up. In the future, it attempts these compatible, and it prepares for the MK-III reactor core operation and it incorporates a final examination result by the improvement of the safety of FBR.

Journal Articles

Electroplating of the superconductive boride MgB$$_{2}$$ from molten salts

Abe, Hideki*; Yoshii, Kenji; Nishida, Kenji*; Imai, Motoharu*; Kitazawa, Hideaki*

Journal of Physics and Chemistry of Solids, 66(1), p.406 - 409, 2005/01

no abstracts in English

27 (Records 1-20 displayed on this page)