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Sanada, Yukihisa; Urabe, Yoshimi*; Misono, Toshiharu; Shiribiki, Takehiko; Nakanishi, Takahiro; Watanabe, Yusuke; Tsuruta, Tadahiko
Scientific Reports (Internet), 11(1), p.23175_1 - 23175_13, 2021/11
Times Cited Count：2 Percentile：12.7(Multidisciplinary Sciences)After the accident at the Fukushima Daiichi Nuclear Power Station (FDNPP) on March 15, 2011, a large amount of volatile radionuclides were released into the atmosphere and hydrosphere. Monitoring of radioactive cesium in sediments is important for assessing the behavior and effects of radioactive cesium in the environment. In this study, the distribution of radioactive cesium in the superficial deposits around FDNPP was visualized as a radioactive cesium map using regular survey data from a towed gamma-ray detection system.
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
JAEA-Review-2021-003.pdf:12.67MB
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.
Fukuda, Kenji; Watanabe, Yusuke; Murakami, Hiroaki; Amano, Yuki; Aosai, Daisuke*; Hara, Naohiro*
JAEA-Data/Code 2020-012, 80 Pages, 2020/10
JAEA-Data-Code-2020-012.pdf:3.55MB
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 2019. 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.
Fukuda, Kenji; Watanabe, Yusuke; Murakami, Hiroaki; Amano, Yuki; Aosai, Daisuke*; Kumamoto, Yoshiharu*; Iwatsuki, Teruki
JAEA-Data/Code 2019-019, 74 Pages, 2020/03
JAEA-Data-Code-2019-019.pdf:3.53MB
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.
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
JAEA-Data-Code-2018-021.pdf:3.78MB
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.
Watanabe, Yusuke; Hayashida, Kazuki; Kato, Toshihiro; Kubota, Mitsuru; Aosai, Daisuke*; Kumamoto, Yoshiharu*; Iwatsuki, Teruki
JAEA-Data/Code 2018-002, 108 Pages, 2018/03
JAEA-Data-Code-2018-002.pdf:6.53MB
Japan Atomic Energy Agency has been investigating groundwater chemistry to understand the effect 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 2016 and 2014 to 2016, respectively. 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; Hayashida, Kazuki; Murakami, Hiroaki; Watanabe, Yusuke
no journal, ,
Geochemical condition and solutes transport property in and around a simulated closure tunnel were studied by observing the behavior of REEs at Mizunami Underground Research Laboratory. Results show that the REEs in the closure tunnel tend to be immobilized by absorbing to shotcrete and the colloidal flocculation.
Watanabe, Yusuke; Hayashida, Kazuki; Murakami, Hiroaki; Iwatsuki, Teruki
no journal, ,
In the geological disposal project of high-level radioactive waste, a disposal facility will be constructed in depths deeper than 300 m. In this study, the simulated experimental tunnel was constructed in the granite of 500 m depth at Mizunami Underground Research Laboratory, and the hydrochemical process after the tunnel closure was observed.
Watanabe, Yusuke; Hayashida, Kazuki; Iwatsuki, Teruki; Suzuki, Yohei*
no journal, ,
The metabolic activities of microorganisms has potential to contribute for formation and keeping of redox condition in the groundwater. In particular, it is possible that the microbial sulfate reduction has great role in formation of reducing condition. However, in situ observation of the activities of sulfate reducing bacteria in the groundwater has not conducted. In this study, we examined relation of redox condition in groundwater with microbial activities by in situ incubation experiment of sulfate reducing bacteria living in borehole drilled in granitic rock at 300 m below ground level at the Mizunami Underground Research Laboratory.
Watanabe, Yusuke; Hayashida, Kazuki; Murakami, Hiroaki; Iwatsuki, Teruki
no journal, ,
In assessing the safety of geological disposal of high-level radioactive waste, groundwater chemistry is an important factor influencing the performance of engineered materials and the behavior of radionuclides. It is essential to understand the hydrochemical changing process and stable condition after the closure of the disposal facilities. In this study, a simulated experimental drift was constructed in granite at a depth of 500 m at the Mizunami Underground Research Laboratory, and the hydrochemical condition and related processes after drift closure were observed.
Munemoto, Takashi*; Watanabe, Yusuke; Hayashida, Kazuki; Iwatsuki, Teruki
no journal, ,
Iwatsuki, Teruki; Murakami, Hiroaki; Watanabe, Yusuke; Fukuda, Kenji
no journal, ,
Drift closure test was carried out to understand the hydrochemical influence of cement materials to groundwater in Mizunami Underground Research Laboratory. In the end, the amount of cement material including portlandite to evolve the alkaline groundwater was quantitatively estimated 0.5mm depth of shotcrete.
Watanabe, Yusuke; Fukuda, Kenji; Murakami, Hiroaki; Iwatsuki, Teruki; Suzuki, Yohei*
no journal, ,
Oxic condition may spread into the deep groundwater by penetrating of shallow oxic groundwater during construction and operation of geological repository for the geological disposal of nuclear waste. On the other hand, microbial activities living in deep underground such as sulfate reducing bacteria could keep the redox condition in groundwater reductive by the reduction of sulfate ion to hydrogen sulfide. In this study, in situ incubation experiment for sulfate reducing bacteria was conducted to observe its redox buffering capacity. Results showed that reducing condition was made by activities of sulfate reducing bacteria in the groundwater.
Iwatsuki, Teruki; Murakami, Hiroaki; Watanabe, Yusuke; Fukuda, Kenji
no journal, ,
We considered the evaluation method of chemical influence of cement material on groundwater when closing tunnel. As a result, it is considered that long-term pH condition around the tunnel can be estimated by thermodynamic analysis of the groundwater flow, the applied cement material, accompanying water chemistry and the amount of alkaline groundwater.
Watanabe, Yusuke; Fukuda, Kenji; Murakami, Hiroaki; Iwatsuki, Teruki; Suzuki, Yohei*
no journal, ,
In this study, microbial incubation experiment was conducted at 300m depth in Mizunami underground research laboratory for the purpose of evaluating the relation between microbial activity and geochemical characteristics in underground environment. In this test, it is necessary to evaluate the microbial activity based on the change in the dissolved component concentration of the groundwater, and it is necessary to grasp the change of the dissolved component due to the exchange of the groundwater in the borehole in advance. Therefore, fluorescent tracer was added to evaluate how the groundwater during the cultivation test spreads into the surrounding rock.
Murakami, Hiroaki; Watanabe, Yusuke; Fukuda, Kenji; Iwatsuki, Teruki
no journal, ,
To understand geological-environment stability at the deep underground, it is important to monitor changes in EdZ. Monitoring after closure of underground facilities is particularly important, however few studies have been reported on post-closure monitoring. We considered about focus points of post-closure monitoring by using hydrochemical data of groundwater in/around Mizunami Underground Research Laboratory. In highly permeable strata such as conglomerate formation, the source of groundwater changes due to URL construction and operation. In this section after URL closure, the water pressure will recover and the source of the groundwater will change again. Therefore, the section greatly influenced by the facility construction and operation should be chosen for post-closure monitoring.
Onoe, Hironori; Murakami, Hiroaki; Ozaki, Yusuke; Watanabe, Yusuke; Takeuchi, Ryuji; Iwatsuki, Teruki
no journal, ,
no abstracts in English
Watanabe, Yusuke; Kashiwaya, Koki*
no journal, ,
no abstracts in English
Watanabe, Yusuke; Kashiwaya, Koki*
no journal, ,
no abstracts in English
