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Ise, Kotaro; Sasaki, Yoshito; Amano, Yuki; Iwatsuki, Teruki; Nanjo, Isao*; Asano, Takahiro*; Yoshikawa, Hideki
Geomicrobiology Journal, 34(6), p.489 - 499, 2017/07
Times Cited Count：6 Percentile：15.66(Environmental Sciences)We investigated the change in bacterial community structure after drilling boreholes, 09-V250-M02 and 09-V250-M03 in the 250 m depth research gallery of Horonobe Underground Research Laboratory (URL). In 09-V250-M02, 
-Proteobacteria was predominantly detected in the clone library analyses of the groundwater samples conducted immediately after drilling the borehole. All these -Proteobacteria clones are closely related to 
. which is known as sulfide oxidizing chemoautotrophic bacteria. After four years, the microbial structure was drastically changed and most detected OTUs were uncultured species such as candidate division OP9 and Chloroflexi relatives which are frequently detected in deep-sea sediments.
Amano, Yuki; Nanjo, Isao; Murakami, Hiroaki; Yabuuchi, Satoshi; Yokota, Hideharu; Sasaki, Yoshito; Iwatsuki, Teruki
Chikasui Gakkai-Shi, 54(4), p.207 - 228, 2012/11
We verified the surface-based hydrochemical investigation for deep underground at Horonobe Underground Research Laboratory (URL) at Horonobe, Hokkaido, Japan, and identified the hydrochemical changes during the URL construction. The evaluation of the relationship between the number of borehole and understanding of water chemistry suggests that three basic borehole investigations and additional borehole for high permeable geological structure (fault and fractured zone) are required to illustrate cross-sectional hydrochemical distribution including the uncertainty in kilometers scale survey line. The observation and numerical analysis of hydrochemical variation (salinity, pH, ORP) around URL indicate that the groundwater pressure and the salinity in the vicinity of high permeable geological zone are varying due to groundwater inflow into the drift. The variation was consistent with the prediction reported previously. These results are considered to be referred to the management during surface-based investigation and construction of underground facility at the other sedimentary rock area.
Nakayama, Masashi; Amano, Kenji; Tokiwa, Tetsuya; Yamamoto, Yoichi; Oyama, Takuya; Amano, Yuki; Murakami, Hiroaki; Inagaki, Daisuke; Tsusaka, Kimikazu; Kondo, Keiji; et al.
JAEA-Review 2012-035, 63 Pages, 2012/09
JAEA-Review-2012-035.pdf:12.23MB
The Horonobe Underground Research Laboratory Project is planned to extend over a period 20 years. The investigations will be conducted in three phases, namely "Phase 1: Surface-based investigations", "Phase 2: Construction Phase" (investigations during construction of the underground facilities) and "Phase 3: Operation phase"(research in the underground facilities). This report summarizes the results of the investigations for the 2011 fiscal year (2011/2012). The investigations, which are composed of "Geoscientific research" and "R&D on geological disposal technology", were carried out according to "Horonobe Underground Research Laboratory Project Investigation Program for the 2011 Fiscal year". The results of these investigations, along with the results which were obtained in other departments of Japan Atomic Energy Agency (JAEA), are properly offered to the implementations and the safety regulations. For the sake of this, JAEA has proceeded with the project in collaboration with experts from domestic and overseas research organisations.
Nanjo, Isao; Amano, Yuki; Iwatsuki, Teruki; Kunimaru, Takanori; Murakami, Hiroaki; Hosoya, Shinichi*; Morikawa, Keita
JAEA-Research 2011-048, 162 Pages, 2012/03
JAEA-Research-2011-048.pdf:8.53MBJAEA-Research-2011-048-appendix(CD-ROM)-1.pdf:0.74MBJAEA-Research-2011-048-appendix(CD-ROM)-2.pdf:7.55MBJAEA-Research-2011-048-appendix(CD-ROM)-3.pdf:18.71MBJAEA-Research-2011-048-appendix(CD-ROM)-4.pdf:0.11MBJAEA-Research-2011-048-appendix(CD-ROM)-5.pdf:0.07MBJAEA-Research-2011-048-appendix(CD-ROM)-6.pdf:0.68MB
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).
Amano, Yuki; Yamamoto, Yoichi; Nanjo, Isao; Murakami, Hiroaki; Yokota, Hideharu; Yamazaki, Masanori; Kunimaru, Takanori; Oyama, Takahiro*; Iwatsuki, Teruki
JAEA-Data/Code 2011-023, 312 Pages, 2012/02
JAEA-Data-Code-2011-023.pdf:5.46MBJAEA-Data-Code-2011-023(errata).pdf:0.08MB
In the Horonobe Underground Research Laboratory (URL) Project, ground water from boreholes, river water and precipitation have been analyzed for the environmental monitoring since the fiscal year 2001. This report shows the data set of water chemistry since the fiscal year 2001 to the fiscal year 2010.
Iwatsuki, Teruki; Amano, Yuki; Murakami, Hiroaki; Nanjo, Isao; Aoki, Kazuhiro; Sasaki, Yoshito; Yoshikawa, Hideki
no journal, ,
This study aims to develop the evaluation methods of environmental changes and the recovery process around a large underground facility. To this end, hydrochemical changes in response to shaft excavation are analyzed based on the observation of water pressure, groundwater chemistry and microbial community structure around the URL. Regarding the chemical disturbance in the area, the redox potential (ORPSHE) of the groundwaters in the monitoring boreholes showed reducing condition (around -200 - -250 mV with pH of approx. 6-7) nevertheless the gallery is in oxidized condition. Theoretical calculation and chemical/microbial analysis of water sample suggests that the dominant redox buffering process around gallery is water-mineral-microbe interaction including iron-, sulphur-bearing materials (mineral and solutes).
Miyakawa, Kazuya; Amano, Yuki; Nanjo, Isao; Murakami, Hiroaki; Yabuuchi, Satoshi; Yokota, Hideharu; Iwatsuki, Teruki
no journal, ,
no abstracts in English
Ise, Kotaro; Nanjo, Isao; Amamiya, Hiroki; Amano, Yuki; Iwatsuki, Teruki; Asano, Takahiro*; Kageyama, Koji*; Sasaki, Yoshito; Yoshikawa, Hideki
no journal, ,
no abstracts in English
Nanjo, Isao; Mizuno, Takashi; Murakami, Hiroaki; Amano, Yuki; Hosoya, Shinichi*; Wakahama, Hiroshi*; Yamashita, Riyo*
no journal, ,
This study aimed to develop a hydrochemical monitoring system for in-situ groundwater. JAEA has developed the hydrochemical monitoring system which is available at underground facility focused on low-permeable sedimentary rocks. After performance test, it can be demonstrated that the monitoring system is workable completely at 350m depth research gallery.
Mizuno, Takashi; Nanjo, Isao; Yamamoto, Nobuyuki; Miyakawa, Kazuya; Murakami, Takuma
no journal, ,
This study aimed to understand the hydrochemical evolution process at Horonobe area, northern Hokkaido Japan, based on chemical tracers. In this study, existing data was used for the estimation. As the result, it is revealed that the resolution of gas hydrate and the diffusion of porewater from upper strata to lower strata is important factor of hydrochemical evolution.
Kimuro, Shingo*; Kirishima, Akira*; Akiyama, Daisuke*; Sato, Nobuaki*; Mizuno, Takashi; Amano, Yuki; Nanjo, Isao*
no journal, ,
no abstracts in English
Nanjo, Isao; Amano, Yuki; Iwatsuki, Teruki; Murakami, Hiroaki; Sasaki, Yoshito; Yoshikawa, Hideki
no journal, ,
The instrument for groundwater monitoring technique, which can continuously monitor the pore water pressure and physico-chemical parameters(pH, EC, DO, ORP, temp) has developed, to monitor the hydrological and geochemical disturbances caused by underground facility construction. It was able to be confirmed that the pore water pressure decrease in all the observation zone by underground facility construction. The relation between spring water and pore water pressure, physico-chemical parameters will be examined by a consecutive observation.
Amano, Yuki; Sasaki, Yoshito; Nanjo, Isao*; Amamiya, Hiroki; Mizuno, Takashi; Ise, Kotaro; Yoshikawa, Hideki
no journal, ,
Continuous monitoring of groundwater chemistry of the boreholes during the facility construction indicated that the salinity around 140 m have not changed from the beggining to date. Water pressures within the area several tens to hundreds meter from the shafts also went down in process of time. Regarding the chemical disturbance in the area, the redox potencial of the groundwaters in the monitoring boreholes showed reducing condition nevertheless the gallery is in oxidized condition. However, microbial community structure changed considerably from the beggining to date. These results indicate that microbial redox reaction could contribute to maintain of reducing conditions in the groundwater system, despite of hydrochemical disturbance caused by facility construction.
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.
Amano, Yuki; Nanjo, Isao; Iwatsuki, Teruki; Sasaki, Yoshito; Asano, Takahiro; Terashima, Motoki; Nagaoka, Toru*; Nakamura, Takamichi*; Yoshikawa, Hideki; Aoki, Kazuhiro
no journal, ,
In-situ experiment of redox reaction was conducted to assess the redox buffur capacity of water-rock-microbes system in the subsurface environment at 140 m depth of Horonobe Underground Research Laboratory. Dissolved oxygen was injected into a borehole, and the physico-chemical parameters (i.e. pH, ORP, DO, EC, etc.) and geochemical composition, microbial cell number, and microbial community structure were monitored continuously during the groundwater circulation. DO concentration could not detected after 10 hours from the injection. The concentration of Fe(II) was decreased with time, then the injected oxygen could be consumed by Fe(II). The rate of oxygen consumption during the experiment was 9.64 mg/L/day. The Eh value become stable at -208 mV after 5 days, then it showed that the reducing condition would be recovered quickly after closed condition.
Murakami, Hiroaki; Amano, Yuki; Nanjo, Isao; Iwatsuki, Teruki
no journal, ,
Constructions such as geological disposal of high-level radioactive waste influence hydraulic and geochemical condition around the facility. Therefore, it is necessary to develop the methodology to evaluate those effects. In this study, we report the results of monitoring for disturbing process of hydrogeochemical conditions of groundwater. Water-collection rings were installed every about 30 m deep in each vertical shafts. The flow rate, physic-chemical parameter (etc. pH, ORP, DO) and chemical composition of groundwater were observed at water-collection rings. Meanwhile, a borehole was drilled at 140 m Niche off the East Shaft. The physic-chemical parameter and hydraulic pressure of groundwater were monitoring at this borehole during drilling of the East Shaft. As a result, it was shown that hydraulic pressure was influenced by drilling the East Shaft in the area from the shaft at least 80 m or more.
Amano, Yuki; Iwatsuki, Teruki; Nanjo, Isao; Sasaki, Yoshito; Asano, Takahiro*; Yoshikawa, Hideki; Nagaoka, Toru*; Nakamura, Takamichi*
no journal, ,
In situ experiments for assessment of redox buffer capacity were conducted at 140 m depth of Horonobe Under Research Laboratory, and demonstrated to recover reducing condition from the oxidation condition by "water-rock-microbes" interactions.
