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Hama, Katsuhiro; Iwasaki, Riyo*; Morikawa, Keita*
JAEA-Technology 2017-015, 45 Pages, 2017/07
Tono Geoscience Center of Japan Atomic Energy Agency has been carrying out the Mizunami Underground Research Laboratory Project. The goal of mass transport study is to obtain a better understanding of mass transport phenomena in the geological environment as well as to develop technologies for measurement of the mass transport parameters, model construction, numerical analysis and validation of those technologies. This experiment was planned to understand the influence of the microscopic structure in the rock mass on the mass transport property. The diffusion experiment using rock sample was carried out. The macroscopic and microscopic observations were carried out to understand the distribution of tracer (uranine) after the diffusion experiment. The uranine was observed in the plagioclase, in the grain boundary and in the microfracture in the mineral grains. These results suggested that distribution of mineral and of microfracture could affect the diffusion property of uranine.
Iwasaki, Riyo*; Hama, Katsuhiro; Morikawa, Keita*; Hosoya, Shinichi*
JAEA-Technology 2016-037, 62 Pages, 2017/02
Mass transport study is mainly performed as part of Phase III in the Mizunami Underground Research Laboratory Project. In Phase III, the goal of mass transport study is to obtain a better understanding of mass transport phenomena in the geological environment as well as to develop technologies for measurement of the mass transport parameters, model construction, numerical analysis and validation of those technologies. This study was planned to understand the influence of the geological characteristics of fracture on the mass transport parameters.
Yamashita, Riyo; Hama, Katsuhiro; Takeuchi, Ryuji; Morikawa, Keita*; Hosoya, Shinichi*; Nakamura, Toshiaki*; Tanaka, Yumiko*
JAEA-Technology 2014-029, 118 Pages, 2014/09
This study is to gain a better understanding of mass transfer phenomena in the geological environment as well as to develop technologies for: measurement of the solute transport parameters, model construction, numerical analysis and validation of all those technologies based on the existing information. As part of solute transport study, laboratory experiments were planned to understand the influence of the geological characteristics of fracture on the solute transport parameters, also understand the differences in test results by the different sizes of the samples used for an experiment, and moreover to validate the parameters obtained by numerical analysis.
Hama, Katsuhiro; Mikake, Shinichiro; Nishio, Kazuhisa; Matsuoka, Toshiyuki; Ishibashi, Masayuki; Sasao, Eiji; Hikima, Ryoichi*; Tanno, Takeo*; Sanada, Hiroyuki; Onoe, Hironori; et al.
JAEA-Review 2013-050, 114 Pages, 2014/02
Japan Atomic Energy Agency (JAEA) at Tono Geoscience Center (TGC) is pursuing a geoscientific research and development project namely the Mizunami Underground Research Laboratory (MIU) Project in crystalline rock environment in order to construct scientific and technological basis for geological disposal of High-level Radioactive Waste (HLW). The MIU Project has three overlapping phases: Surface-based Investigation phase (Phase I), Construction phase (Phase II), and Operation phase (Phase III). The MIU Project has been ongoing the Phase II and the Phase III in fiscal year 2012. This report presents the results of the investigations, construction and collaboration studies in fiscal year 2012, as a part of the Phase II and Phase III based on the MIU Master Plan updated in 2010.
Yamamoto, Nobuyuki; Iwano, Keita*; Namikawa, Tadashi*; Morikawa, Seiji*; Seno, Shoji*; Tabei, Kazuto*; Toida, Masaru*; Yokota, Hideharu
JAEA-Research 2013-003, 252 Pages, 2013/06
This study reconsiders rock's mechanical and hydrological parameters based on additional data given in this year, and conducts the mechanical-hydrological analysis using the Micromechanics-Based Continuum (MBC) model which can consider the behavior of fracture. The acquired analysis results are compared with actual test data such as drift convergence and hydraulic pressure around the drift. Then, following knowledge is obtained.
Yuguchi, Takashi; Ishibashi, Masayuki; Morikawa, Keita; Kunimaru, Takanori
JAEA-Data/Code 2013-004, 38 Pages, 2013/06
Tono Geoscientific Research Unit of Japan Atomic Energy Agency (JAEA) is carrying out the Underground Research Laboratory Project, which is a scientific study revealing the deep geological environment as a basis of research and development for geological disposal of high level radioactive wastes. Nowadays, the project is under the Phase II and Phase III. In the 2011 fiscal year, rock specimens accompanied with grout-filling fracture were collected from -300m Access / Research Gallery of the Mizunami Underground Research Laboratory Construction Site, which were processed into thin sections, and then observed through polarizing microscopy. The grout-filling fracture can be identified as groundwater flow path and thus mass transfer pathway. Investigation methodology and petrological / mineralogical data are basic information for the study of mass transfer in Phase III. This paper presents sampling procedure of rock specimen accompanied with grout-filling fracture and compiles the results of these petrographical observations and analyses.
Kunimaru, Takanori; Morikawa, Keita; Tachi, Yukio; Kuno, Yoshio*; Hosoya, Shinichi*; Shimoda, Satoko*; Kato, Hiroyasu*; Nakazawa, Toshiyuki*; Ikuse, Hiroyuki*; Kubota, Masako*
JAEA-Data/Code 2012-013, 96 Pages, 2012/07
For the purpose to understand the relationship between characteristic of mass transport and characteristic of fracture, the following experiments were carried out using core sample, which was sampled from the -300 m Stage. This paper compiled the results of these experiment. (1) Diffusion experiments of Cs, Sr, I and uranin in granite samples (2) Sorption experiments of Cs and Sr on crushed granite (3) Measurement of pore physicality by Mercury Intrusion and water saturation
Kunimaru, Takanori; Mikake, Shinichiro; Nishio, Kazuhisa; Tsuruta, Tadahiko; Matsuoka, Toshiyuki; Ishibashi, Masayuki; Ueno, Takashi; Tokuyasu, Shingo; Daimaru, Shuji; Takeuchi, Ryuji; et al.
JAEA-Review 2012-020, 178 Pages, 2012/06
Japan Atomic Energy Agency (JAEA) at Tono Geoscience Center (TGC) is pursuing a geoscientific research and development project namely the Mizunami Underground Research Laboratory (MIU) Project in crystalline rock environment in order to construct scientific and technological basis for geological disposal of High-level Radioactive Waste (HLW). The MIU Project has three overlapping phases: Surface-based Investigation phase (Phase I), Construction phase (Phase II), and Operation phase (Phase III). The MIU Project has been ongoing the Phase II. And Phase III started in 2010 fiscal year. This report shows the results of the investigation, construction and collaboration studies in fiscal year 2010, as a part of the Phase II based on the MIU Master Plan updated in 2002.
Nanjo, Isao; Amano, Yuki; Iwatsuki, Teruki; Kunimaru, Takanori; Murakami, Hiroaki; Hosoya, Shinichi*; Morikawa, Keita
JAEA-Research 2011-048, 162 Pages, 2012/03
The observation technique of hydrochemical condition in low permeable sedimentary rock around the facility is one of R&D subjects. We report, (1) development of hydrochemical monitoring system to observe water pressure, pH, electric conductivity, dissolved oxygen, redox potential and temperature, (2) hydrochemical observation results around URL under construction. The applicability of the hydrochemical monitoring system is evaluated for low permeable sedimentary rock bearing abundant dissolved gases. The hydrochemical observation during facility construction demonstrates that pH and redox potential of groundwater almost did not changed even at hydraulic disturbed zone (water pressure decreased zone).
Iwatsuki, Teruki; Morikawa, Keita*; Hosoya, Shinichi*; Yoshikawa, Hideki
Chikasui Gakkai-Shi, 51(3), p.205 - 214, 2009/08
Physicochemical parameters of deep groundwater at the depth of 500 m were measured at ground surface and the in-situ sampling depth of borehole to understand the redox condition and dominant redox process. The results show that the redox potential at the depth was approximately -100 mV and was controlled by the reaction of chemical pairs of (Fe, SO)/(FeS) or (SO, FeCO)/(FeS). The pH value at ground surface changed approximately 0.4 from that at the in-situ depth by degassing of dissolved carbon dioxide. The time to reach the stable ORP value in monitoring depends on the shape and surface area of Pt electrode. The columnar-shape Pt electrode is more sensitive for deep groundwater rather than a dot-shape Pt electrode. It is important to correct the pH measured at ground surface for the analysis of in-situ redox reaction process.
Mori, Takayuki*; Morikawa, Seiji*; Tabei, Kazuto*; Iwano, Keita*; Nakajima, Makoto*
JNC TJ7400 2005-080, 216 Pages, 2005/03
As a first step of Mizunami Underground Research Laboratory Plan (MIU plan), through the laboratory and borehole in-situ tests, JNC Tono Geoscience Center plans to constitute the comprehensive geological model and predicts the rock behaviors in excavating the shaft and gallery. These model and results leads to be reflected by the next step research projects.So far, the first step of MIU plan is coming to final stage, and the second step will start at next year in which the in-situ researches are planned through the excavation. In this study, the comprehensive geometrical model was drawn out through the first step data, and MBC model analysis was carried out to predict the rock mass behavior around the shaft and gallery. The following results are obtained. (1) With MIZ-1 borehole core, artificial joints, which are assumed to be produced by rock blasting, were formed through the Brazilian test. And through the rock shear test for these joints, these mechanical properties were obtained. (2) By examining the MIZ-1 borehole research data, Mizunami site was classified by mechanical and joint properties and the Geomechanical model were made up. (3) Through the MBC model, the shaft and gallery cases were analyzed which depend on the rock mass classification, Excavation Damaged Zone, and the direction of the galleries. These results showed that in most cases, the joint opening were little because of the rock stiffness, but by the existence of high inclined joints, the side wall of the galleries were damaged by the excavation.
Mori, Takayuki*; Morikawa, Seiji*; Tabei, Kazuto*; Iwano, Keita*
JNC TJ7400 2004-006, 58 Pages, 2004/02
JNC Tono Geoscience Center planed a comprehensive geoscientific research program for the construction of an underground research laboratory in order to conduct the research and evaluation of geological environment. So far, based on mechanical data from 1,000-m borehole tests, several numerical analysis models, which consider the behavior of joints in a rock mass, have been applied to this site, and the discontinuous rock behavior around the shafts and galleries has been predicted.However, none of these analyses considered the "Excavation Damaged Zone". In this study, in order to grasp the extent of the Excavation Disturbed Zone, MBC analysis considering the Excavation Damaged Zone was carried out and the following results were obtained. 1.Using several parameters relevant to the rock and joints, a parametric study was performed to verify the effect on and sensitivity of the behavior of the Excavation Disturbed Zone. The results showed that joint frequency and Young's modulus of the rock were much effective parameters. 2.Based on the parametric study, several analyses for shaft and gallery were conducted. As the joint density increased and the area of the Excavation Damaged Zone expanded, the joint opening area increased and the equivalent shear stiffness decreased. 3.Two contrasting cases were also analyzed: one was assumed that pre-existing joints progress in the Excavation Damaged Zone, and the other assumed that joints tangential to the excavation wall are generated in the Excavation Damaged Zone. It was found that Excavation Damaged Zone tends to be larger in the former case than the latter case. 4.From these results, prediction analysis for Excavation Disturbed Zone considering the Excavation Damaged Zone was found to be practical. Through the in-situ monitoring data for shafts and galleries, the validity of these analyses will be verified.
Morikawa, Keita*; Iwatsuki, Teruki; Hosoya, Shinichi*
no journal, ,
Measurement of redox potential in deep groundwater was conducted at ground surface and in-situ monitoring part of borehole to refine the properties of ORP electrode. The results show that the time to reach the stable value of redox potential depends on shape of Pt electrode.
Sanada, Hiroyuki; Sugita, Yutaka; Kunimaru, Takanori; Iwano, Keita*; Morikawa, Seiji*; Seno, Shoji*; Namikawa, Tadashi*
no journal, ,
no abstracts in English
Nanjo, Isao; Kunimaru, Takanori; Iwatsuki, Teruki; Hosoya, Shinichi*; Morikawa, Keita*
no journal, ,
The instrument for groundwater monitoring technique, which can continuously monitor the pore water pressure and physico-chemical parameters has developed, to monitor the hydrological and geochemical disturbances caused by underground facility construction. The pore water pressure was observed almost the same value after the circulation for the measurement of physico-chemical parameters. It was able to be confirmed that the continuous measurement for physico-chemical parameters doesn't influence the observation of pore water pressure.
Yabuuchi, Satoshi; Kunimaru, Takanori; Iwano, Keita*; Morikawa, Seiji*; Namikawa, Tadashi*
no journal, ,
no abstracts in English
Morikawa, Keita; Kunimaru, Takanori
no journal, ,
no abstracts in English
Tanaka, Yasuharu*; Goto, Kazuyuki*; Miyagawa, Kimio*; Tsukuda, Kazuhiro*; Goshima, Keiichiro*; Kunimaru, Takanori; Tsuruta, Tadahiko; Morikawa, Keita; Yuguchi, Takashi
no journal, ,
no abstracts in English
Yuguchi, Takashi; Kunimaru, Takanori; Morikawa, Keita; Uehara, Tomoko
no journal, ,
no abstracts in English
Yuguchi, Takashi; Kunimaru, Takanori; Morikawa, Keita; Uehara, Tomoko; Ishibashi, Masayuki; Yoshida, Hidekazu*; Tanaka, Yasuharu*
no journal, ,
no abstracts in English