Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Kokubu, Yoko; Takeuchi, Ryuji; Nishio, Kazuhisa*; Ikeda, Koki
JAEA-Review 2024-066, 67 Pages, 2025/03
The Tono Geoscience Center of the Japan Atomic Energy Agency has undertaken backfilling and restoration activities at the Mizunami Underground Research Laboratory (MIU) site since fiscal year 2020. These activities are being conducted in accordance with "The MIU Project from FY2020 Onwards," outlining the procedures for backfilling, restoration, and environmental monitoring at the MIU site. The backfilling activity was completed in January 2022, and thereafter, the observation of the backfilled shafts was commenced. On November 6, 2023, the settlement of the backfilled surface was observed in the Main Shaft and the Ventilation Shaft. By December 5, 2023, the depth of the settlement reached 12.9 m in the Main Shaft and 27.7 m in the Ventilation Shaft. After an evaluation by the MIU safety confirmation committee, which assessed the settlement condition and recommended countermeasures, the affected areas were backfilled for safety reasons. This report summarizes the observed settlement of the backfilled surface, the subsequent rebackfilling efforts, and the condition of the surface settlement areas. The condition of the backfilled sections has been confirmed up to June 2024.
Takeuchi, Ryuji; Mikake, Shinichiro; Ikeda, Koki; Nishio, Kazuhisa*; Kokubu, Yoko; Hanamuro, Takahiro
JAEA-Review 2023-007, 114 Pages, 2023/07
Japan Atomic Energy Agency (JAEA) at Tono Geoscience Center has been conducting the Mizunami Underground Research Laboratory (MIU) Project to enhance the reliability of geological disposal technologies through investigations of the deep geological environment in the crystalline rock (granite) at Mizunami City, Gifu Prefecture, central Japan since fiscal year 1996. Backfilling and restoration works in the MIU site have been being conducted based on "the MIU Project from FY2020 onwards" which is defined the way forward of backfilling and restoration works and environmental monitoring investigations in the MIU site, since fiscal year 2020. This report summarizes the outline, process, and achievements of the construction and the safety patrol of the backfilling and restoration works in the MIU site performed from May 16, 2020 to January 16, 2022.
Takeuchi, Ryuji; Onoe, Hironori; Murakami, Hiroaki; Watanabe, Yusuke; Mikake, Shinichiro; Ikeda, Koki; Iyatomi, Yosuke; Nishio, Kazuhisa*; Sasao, Eiji
JAEA-Review 2021-003, 63 Pages, 2021/06
The Mizunami Underground Research Laboratory (MIU) Project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of geological disposal technologies through investigations of the deep geological environment in the crystalline rock (granite) at Mizunami City, Gifu Prefecture, central Japan. On the occasion of JAEA reformation in FY2014, JAEA identified three remaining important issues on the geoscientific research program based on the synthesized latest results of research and development (R&D): "Development of countermeasure technologies for reducing groundwater inflow", "Development of modeling technologies for mass transport" and "Development of drift backfilling technologies". At the MIU, the R&D are being pursued with a focus on the remaining important issues from FY2015, and satisfactory results have been achieved. Based on this situation, the R&D on the MIU Project were completed at the end of FY2019. In this report, the results of R&D and construction activities of the MIU Project in FY2019 are summarized.
Takeuchi, Ryuji; Iwatsuki, Teruki; Matsui, Hiroya; Nohara, Tsuyoshi; Onoe, Hironori; Ikeda, Koki; Mikake, Shinichiro; Hama, Katsuhiro; Iyatomi, Yosuke; Sasao, Eiji
JAEA-Review 2020-001, 66 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 geological disposal technologies through investigations of the deep geological environment in the crystalline rock (granite) at Mizunami City, Gifu Prefecture, central Japan. On the occasion of JAEA reformation in 2014, JAEA identified three remaining important issues on the geoscientific research program based on the synthesized latest results of research and development (R&D): "Development of countermeasure technologies for reducing groundwater inflow", "Development of modeling technologies for mass transport" and "Development of drift backfilling technologies". The R&D on three remaining important issues have been carrying out in the MIU Project. In this report, the current status of R&D and construction activities of the MIU Project in fiscal year 2018 is summarized.
Takeuchi, Ryuji; Iwatsuki, Teruki; Matsui, Hiroya; Ikeda, Koki; Mikake, Shinichiro; Hama, Katsuhiro; Iyatomi, Yosuke; Matsuoka, Toshiyuki; Sasao, Eiji
JAEA-Review 2019-014, 30 Pages, 2019/10
The Mizunami Underground Research Laboratory (MIU) Project is being pursued by the Japan Atomic Energy Agency(JAEA) to enhance the reliability of geological disposal technologies through investigations of the deep geological environment in the crystalline host rock(granite) at Mizunami City, Gifu Prefecture, central Japan. On the occasion of the reform of the entire JAEA organization in 2014, JAEA identified three important remaining issues on the geoscientific research program based on the synthesized latest results of research and development (R&D): "Development of countermeasure technologies for reducing groundwater inflow", "Development of modeling technologies for mass transport" and "Development of drift backfilling technology". The R&D on three remaining important issues have been carrying out in the MIU Project. This report summarizes the R&D activities planned for fiscal year 2019 on the basis of the MIU Master Plan updated in 2015 and Investigation Plan for the Third Medium to Long-term Research Phase.
Takeuchi, Ryuji; Iwatsuki, Teruki; Matsui, Hiroya; Nohara, Tsuyoshi; Onoe, Hironori; Ikeda, Koki; Mikake, Shinichiro; Hama, Katsuhiro; Iyatomi, Yosuke; Sasao, Eiji
JAEA-Review 2019-005, 76 Pages, 2019/06
The Mizunami Underground Research Laboratory (MIU) project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of geological disposal technologies through investigations of the deep geological environment in the crystalline rock (granite) at Mizunami City, Gifu Prefecture, central Japan. On the occasion of the research program and management system revision of the entire JAEA organization in 2014, JAEA identified three remaining important issues on the geoscientific research program based on the latest results of the synthesizing research and development: "Development of countermeasure technologies for reducing groundwater inflow", "Development of modeling technologies for mass transport" and "Development of drift backfilling technologies". The research and development on three remaining important issues have been carrying out on the MIU project. In this report, the current status of the research and development activities and construction in fiscal year 2017 is summarized.
Matsui, Hiroya; Mikake, Shinichiro; Ikeda, Koki; Tsutsue, Jun
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.
Takeuchi, Ryuji; Iwatsuki, Teruki; Matsui, Hiroya; Ikeda, Koki; Mikake, Shinichiro; Hama, Katsuhiro; Iyatomi, Yosuke; Sasao, Eiji
JAEA-Review 2018-019, 29 Pages, 2018/12
The Mizunami Underground Research Laboratory (MIU) Project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of geological disposal technologies through investigations of the deep geological environment in the crystalline host rock (granite) at Mizunami, Gifu Prefecture, central Japan. On the occasion of the reform of the entire JAEA organization in 2014, JAEA identified three important issues on the geoscientific research program: "Development of countermeasure technologies for reducing groundwater inflow", "Development of modelling technologies for mass transport" and "Development of drift backfilling technology", based on the latest results of the synthesizing research and development (R&D). The R&D on three remaining important issues have been carrying out on the MIU Project. This report summarizes the R&D activities planned for fiscal year 2018 on the basis of the MIU Master Plan updated in 2015 and Investigation Plan for the Third Medium to Long-term Research Phase.
Mikake, Shinichiro; Ikeda, Koki; Matsui, Hiroya; Tsuji, Masakuni*; Nishigaki, Makoto*
Doboku Gakkai Rombunshu, C (Chiken Kogaku) (Internet), 74(1), p.76 - 91, 2018/03
Pre-grouting of shafts and galleries had been conducted during the construction of MIU in the aspect of reducing water inflow. After excavating GL.-500m gallery, a post-grouting was performed on section of the pre-excavation grouting area under high water pressure condition (max: 4MPa). The post-grouting experiment was performed outside of the pre-grouting zone with designs, applying colloidal silica grouting material and complex dynamic grouting. It was estimated that the inflow after post-grouting was reduced by 1/100 of the case that pre- and post-grouting were not performed. These results indicate that the applied combined pre- and post-grouting methodology is effective in reducing water inflow and it can be applicable under high water pressure condition. Then, this paper states the theoretical evaluation of relationship between reduction of hydraulic conductivity and the grouting zone is very convenient and useful for grouting design and estimate of water inflow.
Ishibashi, Masayuki; Hama, Katsuhiro; Iwatsuki, Teruki; Matsui, Hiroya; Takeuchi, Ryuji; Nohara, Tsuyoshi; Onoe, Hironori; Ikeda, Koki; Mikake, Shinichiro; Iyatomi, Yosuke; et al.
JAEA-Review 2017-026, 72 Pages, 2018/01
The Mizunami Underground Research Laboratory (MIU) project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of geological disposal technologies through investigations of the deep geological environment in the crystalline host rock (granite) at Mizunami, Gifu Prefecture, central Japan. On the occasion of the research program and management system revision of the entire JAEA organization in 2014, JAEA identified three important issues on the geoscientific research program: "Development of countermeasure technologies for reducing groundwater inflow", "Development of modeling technologies for mass transport" and "Development of drift backfilling technologies", based on the latest results of the synthesizing research and development (R&D). The R&D on three important issues have been carrying out on the MIU project. In this report, the current status of R&D activities and construction in 2016 is summarized.
Tsuji, Masakuni*; Ikeda, Koki; Mikake, Shinichiro; Matsui, Hiroya
Tunnelling Activities in Japan 2018, P. 23, 2018/00
We have recently conducted pre- and post-grouting works at a gallery in 500m depth of MIU. The groundwater pressure was maximum 4.0MPa. As a result, water ingress was reduced to a one-hundredth of an assumed amount with no grouting were performed, which is reduction from approx. Moreover, after a later post-grouting work repeated in the most wet section of the relevant gallery, all dripping spots turned out to be lower than 1 L/min. Especially for the post-grouting technologies, three new concepts were demonstrated and found to be effective; which is the Colloidal silica grout for a new material, Complex dynamic grouting method for a new injection method, and sealing outer area of pre-grouted zones for a new grouting area as design concepts.
Ishibashi, Masayuki; Hama, Katsuhiro; Iwatsuki, Teruki; Matsui, Hiroya; Takeuchi, Ryuji; Ikeda, Koki; Mikake, Shinichiro; Iyatomi, Yosuke; Sasao, Eiji; Koide, Kaoru
JAEA-Review 2017-019, 29 Pages, 2017/10
The Mizunami Underground Research Laboratory (MIU) project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of geological disposal technologies through investigations of the deep geological environment in the crystalline host rock (granite) at Mizunami City in Gifu Prefecture, central Japan. On the occasion of the reform of the entire JAEA organization in 2014, JAEA identified three important issues on the geoscientific research program: "Development of countermeasure technologies for reducing groundwater inflow", "Development of modelling technologies for mass transport" and "Development of drift backfilling technology", based on the latest results of the synthesizing research and development (R&D). These R&D on three remaining important issues have been carrying out on the MIU project. This report summarizes the R&D activities planned for fiscal year 2017 based on the MIU Master Plan updated in 2015 and so on.
Matsui, Hiroya; Mikake, Shinichiro; Ikeda, Koki; Sasaki, Sadao
Dai-14-Kai Iwa No Rikigaku Kokunai Shimpojiumu Koen Rombunshu (Internet), 6 Pages, 2017/01
Japan Atomic Energy Agency (JAEA) has been conducting the groundwater recovery experiment to develop the methodology to estimate the recovery of geological environment after drift closure at GL-500m in Mizunami Underground Research Laboratory, Gifu prefecture, Japan. For the experiment, the impervious concrete plug was constructed to keep a recovered water pressure. The authors assessed the functions of the pluge based on monitoring and interpretation of the several kinds of measurements inside and outside of the plug during groundwater recovery process in a drift. As the results, the design concept and the expected function of the impervious plug assessed almost satisfied and it is supposed no problem will occur on the groundwater recovery experiment for several months.
Hama, Katsuhiro; Iwatsuki, Teruki; Matsui, Hiroya; Mikake, Shinichiro; Ishibashi, Masayuki; Onoe, Hironori; Takeuchi, Ryuji; Nohara, Tsuyoshi; Sasao, Eiji; Ikeda, Koki; et al.
JAEA-Review 2016-023, 65 Pages, 2016/12
The Mizunami Underground Research Laboratory (MIU) project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of geological disposal technologies through investigations of the deep geological environment in the crystalline host rock (granite) at Mizunami City in Gifu Prefecture, central Japan. On the occasion of the reform of the entire JAEA organization in 2014, JAEA identified three important issues on the geoscientific research program: "Development of countermeasure technologies for reducing groundwater inflow", "Development of modelling technologies for mass transport" and "Development of drift backfilling technologies", based on the latest results of the synthesizing research and development (R&D). These R&D on three important issues have been carrying out on the MIU project. In this report, the current status of R&D activities and construction in 2015 is summarized.
Hama, Katsuhiro; Takeuchi, Ryuji; Iwatsuki, Teruki; Sasao, Eiji; Mikake, Shinichiro; Ikeda, Koki; Matsui, Hiroya; Osawa, Hideaki
JAEA-Review 2016-015, 29 Pages, 2016/07
The Mizunami Underground Research Laboratory (MIU) project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of geological disposal technologies through investigations of the deep geological environment in the crystalline host rock (granite rock) at Mizunami City in Gifu Prefecture, central Japan. On the occasion of the reform of the entire JAEA organization in 2014, JAEA identified three important issues on the geoscientific research program: "Development of countermeasure technologies for reducing groundwater inflow", "Development of modelling technologies for mass transport" and "Development of drift backfilling technologies", based on the latest results of the synthesizing research and development (R&D). These R&D on three remaining important issues have been carrying out on the MIU project. This report summarizes the R&D activities planned for fiscal year 2016 based on the MIU Master Plan updated in 2015 and so on.
Hama, Katsuhiro; Mikake, Shinichiro; Ishibashi, Masayuki; Sasao, Eiji; Kuwabara, Kazumichi; Ueno, Tetsuro; Onuki, Kenji*; Beppu, Shinji; Onoe, Hironori; Takeuchi, Ryuji; et al.
JAEA-Review 2015-024, 122 Pages, 2015/11
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 technical 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 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. This report presents the results of the investigations, construction and collaboration studies in fiscal year 2014.
Hama, Katsuhiro; Takeuchi, Ryuji; Saegusa, Hiromitsu; Iwatsuki, Teruki; Sasao, Eiji; Mikake, Shinichiro; Ikeda, Koki; Sato, Toshinori; Osawa, Hideaki; Koide, Kaoru
JAEA-Review 2015-021, 27 Pages, 2015/10
The Mizunami Underground Research Laboratory (MIU) project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of geological disposal technologies through investigations of the deep geological environment in the crystalline host rock (granite rock) at Mizunami City in Gifu Prefecture, central Japan. This report summarizes the research and development activities planned for fiscal year 2015 based on the MIU Master Plan updated in 2015 and so on. On the occasion of the reform of the entire JAEA organization in 2014, JAEA identified the critical issues on the geoscientific research program: "Development of modelling technologies for mass transport", "Development of drift backfilling technologies" and "Development of technologies for reducing groundwater inflow", based on the latest results of the synthesizing R&D. Investigations on those critical issues will be performed at the MIU in fiscal year 2015.
Hama, Katsuhiro; Mikake, Shinichiro; Nishio, Kazuhisa; Kawamoto, Koji; Yamada, Nobuto; Ishibashi, Masayuki; Murakami, Hiroaki; Matsuoka, Toshiyuki; Sasao, Eiji; Sanada, Hiroyuki; et al.
JAEA-Review 2014-038, 137 Pages, 2014/12
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 2013. This report presents the results of the investigations, construction and collaboration studies in fiscal year 2013, as a part of the Phase II and Phase III based on the MIU Master Plan updated in 2010.
Hama, Katsuhiro; Mikake, Shinichiro; Nishio, Kazuhisa; Sasao, Eiji; Saegusa, Hiromitsu; Iwatsuki, Teruki; Ikeda, Koki; Sato, Toshinori; Osawa, Hideaki; Koide, Kaoru
JAEA-Review 2014-035, 34 Pages, 2014/10
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 through investigations of the deep geological environment within the host crystalline rock at Mizunami City in Gifu, 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 planned for fiscal year 2014 based on the MIU Master Plan updated in 2010.
Kawamoto, Koji; Murakami, Hiroaki; Ishibashi, Masayuki; Sasao, Eiji; Watanabe, Kazuhiko; Mikake, Shinichiro; Ikeda, Koki
JAEA-Data/Code 2014-014, 27 Pages, 2014/08
This document presents the data of geological investigations at the -500m stage of the MIU from the 2011 fiscal year to the 2013 fiscal year. At the -500m stage of the MIU, although the Cretaceous Toki granite is distributed, pegmatite, aplite and lampropyre dike are distributed partially.