Yuguchi, Takashi*; Ogita, Yasuhiro; Kato, Takenori*; Yokota, Rintaro*; Sasao, Eiji; Nishiyama, Tadao*
Journal of Asian Earth Sciences, 192, p.104289_1 - 104289_16, 2020/05
Quartz from a granitic pluton is found to have formed through sequential growth events under different mechanisms and crystallization temperatures, which can provide new insights into magmatic processes of granitic magmas that were eventually consolidified into plutons. The events were identified using (1) the description of crystal shape and occurrence, (2) the study of the internal structure with cathodoluminescence (CL), and (3) derivation of the crystallization temperatures based on TitaniQ thermometry. The magmatic quartz crystals from the Toki granite, central Japan, are characterized as having the following internal structures: oscillatory zonation, no-oscillatory zonation with luminescence graduation (gradational zonation), and heterogeneous CL. The quartz crystals with oscillatory zonation were formed in the temperature range of about 800 C to below 700 C, which is referred to as oscillatory zoning temperature (OZT) conditions. The CL zonation pattern was controlled by the temperature conditions and titanium diffusivity in the melt (magma). The crystallization process of quartz within the Toki granite reveals the cooling processes of the granitic pluton; the lithofacies with a high frequency of oscillatory-zoned quartz underwent slower cooling under the OZT conditions than those in other lithofacies.
Nippon Genshiryoku Gakkai-Shi, 62(4), p.186 - 190, 2020/04
no abstracts in English
Okihara, Mistunobu*; Yahagi, Ryoji*; Iwatsuki, Teruki; Takeuchi, Ryuji; Murakami, Hiroaki
JAEA-Technology 2019-021, 77 Pages, 2020/03
One of the major subjects of the ongoing geoscientific research program, the Mizunami Underground Research Laboratory (MIU) Project in the Tono area, central Japan, is accumulation of knowledge on monitoring techniques of the geological environment. In this report, the conceptual design of the monitoring system for groundwater pressure and water chemistry was carried out. The currently installed and used system in research galleries at various depths was re-designed to make it possible to collect groundwater and observe the water pressure on the ground.
Matsuoka, Toshiyuki; Hama, Katsuhiro
JAEA-Research 2019-012, 157 Pages, 2020/03
The Mizunami Underground Research Laboratory (MIU) Project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of relevant disposal technologies for geological disposal of High-level Radioactive Waste through investigations of the deep geological environment within the host crystalline rock at Mizunami City in Gifu Prefecture, central Japan. The project proceeds in three overlapping phases, "Phase I: Surface-based investigation Phase", "Phase II: Construction Phase" and "Phase III: Operation Phase". The MIU Project has been ongoing the Phase III, as the Phase II was concluded for a moment with the completion of the excavation of horizontal tunnels at GL-500m level in February 2014. The present report summarizes the research and development activities carried out mainly in the GL-500m stage during Third Medium to Long-term Research Phase.
Fukuda, Kenji; Watanabe, Yusuke; Murakami, Hiroaki; Amano, Yuki; Aosai, Daisuke*; Kumamoto, Yoshiharu*; Iwatsuki, Teruki
JAEA-Data/Code 2019-019, 74 Pages, 2020/03
Japan Atomic Energy Agency has been investigating groundwater chemistry to understand the influence of excavation and maintenance of underground facilities as part of the Mizunami Underground Research Laboratory (MIU) Project in Mizunami, Gifu, Japan. In this report, we compiled data of groundwater chemistry and microbiology obtained at the MIU in the fiscal year 2018. In terms of ensuring traceability of data, basic information (e.g. sampling location, sampling time, sampling method and analytical method) and methodology for quality control are described.
Matsui, Hiroya; Watanabe, Kazuhiko*; Mikake, Shinichiro; Niimi, Katsuyuki*; Kobayashi, Shinji*; Toguri, Satohito*
Dai-47-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koenshu (Internet), p.293 - 298, 2020/01
Japan Atomic Energy Agency has been observed seismic motions induced by earthquakes, at ground surface, galleries at 100m, 300m and 500m depth of Mizunami underground research laboratory for over 10 years. The results suggested that the amplitude of the seismic motion decreases with depth as the previous study on crystalline rock at Kamaishi mine indicated. Detailed analysis on the observed seismic motions shows that the Fourier amplitude and the phase difference of the earthquake occurred near epicenter correspond with the one calculated by one-dimensional multiple reflection theory.
Onoe, Hironori; Takeuchi, Ryuji
JAEA-Data/Code 2019-010, 41 Pages, 2019/12
Japan Atomic Energy Agency (JAEA) has been conducting a wide range of geoscientific research in order to build scientific and technological basis for geological disposal of nuclear wastes. This study aims to establish comprehensive techniques for the investigation, analysis and assessment of the deep geological environment in fractured crystalline rock. The Regional Hydrogeological Study (RHS) project is a one of the geoscientific research program at Tono Geoscience Center. This project started since April 1992 and main investigations were finished to FY 2004. Since FY 2005, hydrogeological and hydrochemical monitoring have been continued using the existing monitoring system. This report describes the results of the long term hydro-pressure monitoring from April 2018 to March 2019.
Chishitsu To Chosa, (154), p.67 - 72, 2019/11
JAEA is implementing the Mizunami Underground Research Laboratory Project, which is a geoscientific research program in crystalline rock environment in Mizunami City, Japan. This report summarise history, progress and present situation of the project and also history of R&D in the Tono Geoscience Center.
Ichikawa, Yasuaki*; Kimoto, Kazushi*; Matsui, Hiroya
JAEA-Research 2019-005, 32 Pages, 2019/10
It is important to evaluate the mechanical stability around the geological repository for high-level radioactive waste, during not only the design, construction and operation phases, but also the post-closure period over several millennia. The rock mass around the tunnels could be deformed in response to time dependent behaviors such as creep and stress relaxation. Therefore, this study has started as a joint research with Okayama University from 2016. This report summarize the results of the joint research performed in fiscal year 2017 and 2018. Based on the research results obtained in fiscal year 2016, automatic measurement system was developed, which can collect very large data on surface elastic wave propagation in a short time, also the applicability of various kinds of parameters derived from measured elastic wave data was examined.
Onoe, Hironori; Takeuchi, Ryuji
JAEA-Data/Code 2019-009, 22 Pages, 2019/10
Tono Geoscience Center of Japan Atomic Energy Agency (JAEA) 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). As for The MIU Project (Phase II) was carried out from 2004 fiscal year, and has been started the Phase III in 2010 fiscal year. The groundwater inflow monitoring into shafts and research galleries, has been maintained to achieve the Phase II goals, begins in 2004 fiscal year and follows now. This document presents the results of the groundwater inflow monitoring from fiscal year 2016 to 2018.
Nohara, Tsuyoshi; Uno, Masaoki*; Tsuchiya, Noriyoshi*
Geofluids, 2019, p.6053815_1 - 6053815_16, 2019/08
Amphibole-plagioclase thermometry was applied to estimate the temperature of a glassy vein as approximately 700. The results of observations of the rock core revealed that of supercritical fluid flow was microfracture filling with hornblende and plagioclase. The current high permeability was recognized to be microfracture network. A high-angle fracture of chlorite filling in combination with an open fracture was recognized as characteristics of a high-permeability type.
Kono, Masaru*; Hayama, Kazunori*; Matsui, Hiroya; Ozaki, Yusuke
JAEA-Technology 2019-011, 35 Pages, 2019/07
To verify long-term safety performance of the sensor for decades, we decided the extension of the collaborative research and the evaluation test of long-term durability of fiber-optic crack detection sensor developed by Tokyo Measuring Instruments Laboratory Co., Ltd. at the Mizunami Underground Research Laboratory were continued from FY 2015 to FY 2018. As a result, the measurement system using of the fiber-optic crack detection sensor is applicable for long-term measurement in deep underground area and find the future subject.
Nakata, Kotaro*; Hasegawa, Takuma*; Solomon, D. K.*; Miyakawa, Kazuya; Tomioka, Yuichi*; Ota, Tomoko*; Matsumoto, Takuya*; Hama, Katsuhiro; Iwatsuki, Teruki; Ono, Masahiko*; et al.
Applied Geochemistry, 104, p.60 - 70, 2019/05
no abstracts in English
Toguri, Satohito*; Yahagi, Ryoji*; Okihara, Mistunobu*; Takeuchi, Nobumitsu*; Kurosaki, Hiromi*; Matsui, Hiroya
JAEA-Technology 2018-017, 161 Pages, 2019/03
The Japan Atomic Energy Agency has been conducting research on three critical issues for development of: engineering techniques for underground construction, modelling techniques of mass transfer and tunnel backfilling methods at the Mizunami Underground Research Laboratory on the basis of Medium to Long-Term Plan of Japan Atomic Energy Agency. This report describes the overall plan of in-situ test to backfill a part of Mizunami Underground Research Laboratory, which is planned for "development of tunnel backfilling method".
Iwatsuki, Teruki; Onoe, Hironori; Ishibashi, Masayuki; Ozaki, Yusuke; Wang, Y.*; Hadgu, T.*; Jove-Colon C. F.*; Kalinina, E.*; Hokr, M.*; Balvn, A.*; et al.
JAEA-Research 2018-018, 140 Pages, 2019/03
DECOVALEX-2019 Task C aims to develop modelling and prediction methods using numerical simulation based on the water-filling experiment to examine the post drift-closure environment recovery processes. In this intermediate report, the results of Step 1 (Modelling and prediction of environmental disturbance by CTD excavation) are summarized from each of the research teams (JAEA, Sandia National Laboratories, Technical University of Liberec). Groundwater inflow rates to the tunnel during the excavation, hydraulic drawdown, and variation of chlorine concentration at monitoring boreholes in the vicinity of the tunnel were chosen as comparison metrics for Step1 by mutual agreement amongst the research teams. It is likely to be possible to foresee the scales of inflow rate and hydraulic drawdown based on a data from the pilot borehole by current simulation techniques.
Fukuda, Kenji; Watanabe, Yusuke; Murakami, Hiroaki; Amano, Yuki; Hayashida, Kazuki*; Aosai, Daisuke*; Kumamoto, Yoshiharu*; Iwatsuki, Teruki
JAEA-Data/Code 2018-021, 76 Pages, 2019/03
Japan Atomic Energy Agency has been investigating groundwater chemistry to understand the influence of excavation and maintenance of underground facilities as part of the Mizunami Underground Research Laboratory (MIU) Project in Mizunami, Gifu, Japan. In this report, we compiled data of groundwater chemistry and microbiology obtained at the MIU in the fiscal year 2017. In terms of ensuring traceability of data, basic information (e.g. sampling location, sampling time, sampling method and analytical method) and methodology for quality control are described.
Iwatsuki, Teruki; Shibata, Masahito*; Murakami, Hiroaki; Watanabe, Yusuke; Fukuda, Kenji
Doboku Gakkai Rombunshu, G (Kankyo) (Internet), 75(1), p.42 - 54, 2019/03
In order to clarify the influence of shotcrete in the underground facility on the groundwater chemistry, an in-situ closed test was conducted in the mock-up tunnel at the depth of 500 m. Brucite, Ettringite, Ca(OH) , Gibbsite, KCO, NaCO 10HO, SiO (a) and Calcite were identified as the dominant minerals affecting the water chemistry. Furthermore, the shotcrete constructed in the tunnel has a reaction capacity which can produce about 570 m of alkaline groundwater (pH12.4) saturated with Ca(OH). The estimation would improve the accuracy of prediction analysis of the long-term chemical influence of cement materials after the closure of the tunnel.
Geoscience Facility Construction Section, Tono Geoscience Center
JAEA-Review 2018-026, 92 Pages, 2019/02
This progress report presents an outline compilation of construction activities, primary tasks performed, construction progress and safety patrol report, in Fiscal Year 2016-2017. The outline of construction activities is a summary based on the scope of work planned in Fiscal Year 2016-2017: the main activities are based on the Tono Geoscience Center weekly reports; and the construction progress is based on the planned and actual schedules. Regarding the actual performance of the construction work of MIU part VII (March 16, 2016 -March 15, 2018) performance carried out from April 1, 2016 until March 15, 2018 is described in this report and the performance started from March 16, 2018 is supposed to be described in progress report of construction work of MIU part VIII.
Ishida, Tsuyoshi*; Fujito, Wataru*; Yamashita, Hiroto*; Naoi, Makoto*; Fujii, Hirokazu*; Suzuki, Kenichiro*; Matsui, Hiroya
Rock Mechanics and Rock Engineering, 52(2), p.543 - 553, 2019/02
We pressurized and injected water in a hole drilled downward from a floor of the 500 m level gallery in MIU, central Japan. Acoustic emissions (AEs) monitored with 16 sensors in four boreholes located 1 m away from the HF hole exhibited two-dimensional distributions, which likely delineate a crack induced by the fracturing. Expansions of the regions in which AEs occurred were observed only immediately after the first and second BDs. Many AE events in other periods were distributed within the regions where AE events had already occurred. The initial motion polarities of P-waves indicate that tensile-dominant AE events occurred when the regions expanded and they were distributed primarily on the frontiers of the regions where AE events had already occurred. The experimental results suggest that increasing the injection flow rate is effective for generating new cracks in the refracturing, with the new crack expansions being induced by tensile fracturing.
Matsui, Hiroya; Mikake, Shinichiro; Ikeda, Koki; Tsutsue, Jiyun
Dai-46-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koenshu (CD-ROM), p.286 - 291, 2019/01
Japan Nuclear Energy Agency (JAEA) has been conducting the groundwater recovery experiment to develop a methodology to estimate the geological environment recovery after closure of the drift at GL-500m in Mizunami Underground Research Laboratory, Japan. For the experiment, an impervious concrete plug was constructed to maintain a recovered water pressure and its functions were assessed based on the monitoring results and interpretation of several kinds of measurements performed inside and outside of the plug during groundwater recovery test. This report summarized the change of the condition of the plug due to groundwater recovery estimated based on the different kinds of monitoring data.