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Terashima, Motoki; Endo, Takashi*; Kimuro, Shingo; Beppu, Hikari*; Nemoto, Kazuaki*; Amano, Yuki
Journal of Nuclear Science and Technology, 60(4), p.374 - 384, 2023/04
Times Cited Count:2 Percentile:29.47(Nuclear Science & Technology)Munemoto, Takashi; Omori, Kazuaki*; Iwatsuki, Teruki
Chemical Geology, 417, p.58 - 67, 2015/12
Times Cited Count:35 Percentile:73.10(Geochemistry & Geophysics)Rare earth elements (REEs) combined with yttrium (YREE) in deep groundwater from granite and fracture-filling calcite are being studied at the Mizunami Underground Research Laboratory (MIU, Tono area, central Japan).
Iwatsuki, Teruki; Hagiwara, Hiroki; Omori, Kazuaki; Munemoto, Takashi; Onoe, Hironori
Environmental Earth Sciences, 74(4), p.3041 - 3057, 2015/08
Times Cited Count:18 Percentile:54.68(Environmental Sciences)Changes of hydrochemical condition resulting from large-scale underground facility construction to 500 m depth in sedimentary and granitic rock were evaluated at the Mizunami Underground Research Laboratory (MIU), Japan. The investigation of hydrochemical impact around the facility suggests that an understanding of hydrogeological structures, including hydrogeological compartments prior to facility construction and the locating of shafts/galleries in low permeability rock area is essential to minimize hydrochemical disturbances.
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.
Omori, Kazuaki; Hasegawa, Takashi; Munemoto, Takashi; Masuda, Kaoru*; Aosai, Daisuke*; Inui, Michiharu*; Iwatsuki, Teruki
JAEA-Data/Code 2014-019, 121 Pages, 2014/12
Japan Atomic Energy Agency has been investigating the groundwater chemistry on excavating the underground facilities as part of the Mizunami Underground research Laboratory (MIU) Project at Mizunami City, Gifu Prefecture, Japan. In this report, we compiled data obtained by geochemical research for groundwater at the MIU in the fiscal year 2013.
Omori, Kazuaki; Munemoto, Takashi; Hasegawa, Takashi; Shingu, Shinya*; Hagiwara, Hiroki; Iwatsuki, Teruki
JAEA-Research 2014-013, 29 Pages, 2014/08
We summarized investigation method of colloid in groundwater. We examined the ultrafiltration of groundwater by using in-situ water monitoring system and batch type airtight container. Additionally, we examined the cross flow filtration method replaced by ultrafiltration. The knowledge of investigating methods is obtained.
Iwatsuki, Teruki; Yuguchi, Takashi; Omori, Kazuaki; Hasegawa, Takashi; Munemoto, Takashi
JAEA-Research 2013-021, 63 Pages, 2013/12
We evaluated the Phase I - hydrogeochemical model constructed by Surface-based investigation phase (Phase I), and observed hydrogeochemical change resulting from facility construction in Phase II research. Additionally we developed investigation technique on redox condition, colloid/organics, etc. at gallery in Phase III research. Hydrogeochemical changes in sedimentary rocks and granite resulting from facility construction have been caused by the change of mixing ratio among salinity-distinct groundwaters. Multivariate numerical analysis shows that the groundwater chemistry around drifts would change to that of shallow groundwater in the future. The know-hows on hydrochemical monitoring at the hydrogeological structures and numerical analysis were summarized to infer the hydrochemical changing processes during the facility construction.
Takahashi, Hiroaki; Nemoto, Kazuaki; Tachi, Yukio; Katayama, Misaki*; Inada, Yasuhiro*
2012-Nendo Ritsumeikan Daigaku Sogo Kagaku Gijutsu Kenkyu Kiko Sentan Kenkyu Shisetsu Kyoyo Sokushin Jigyo Seika Hokokusho (Internet), 2 Pages, 2013/00
The diffusion profiles of strongly sorbing nuclides such as Cm, Am, Ni, in a compacted bentonite show two parts with different slopes which cannot be fitted by simple one-dimensional diffusion model considering single species. The reason for this anomalous diffusion behavior is not understood. Some XANES spectral shape of Ni diffused in compacted montmorillonite, which is main content of bentonite, at relatively higher concentrated region exhibit slight broadening of a feature on the high-energy side of the white line. The broadening of a feature doesn't appear in the case of Ni aqueous solution and Ni-montmorillonite. These results indicate that the inner coordination geometry of the Ni(II) ion diffused in compacted montmorillonite at relatively higher concentrated region.
Kanayama, Fumihiko; Hagiya, Kazuaki; Sunaoshi, Mizuho; Muraguchi, Yoshinori; Satomi, Shinichi; Nemoto, Koichi; Terunuma, Akihiro; Shiraishi, Kunio; Ito, Shinichi
JAEA-Technology 2011-011, 36 Pages, 2011/06
Dismantling activities of equipments in JAERI's Reprocessing Test Facility (JRTF) started from 1996 as a part of decommissioning of this facility. Removing out of the large liquid waste storage tank LV-2 as a whole tank without cutting in pieces from the annex building B to confirm safety and efficiency of this method started from 2006. After preparatory works, ceiling of LV-2 room was opened, and LV-2 was transferred. Useful data were collected on manpower, radiation control and waste amount through the preparatory works, and work efficiency was analyzed by use of these data.
Ebisawa, Hiroyuki; Hanakawa, Hiroki; Asano, Norikazu; Kusunoki, Hidehiko; Yanai, Tomohiro; Sato, Shinichi; Miyauchi, Masaru; Oto, Tsutomu; Kimura, Tadashi; Kawamata, Takanori; et al.
JAEA-Technology 2009-030, 165 Pages, 2009/07
The condition of facilities and machinery used continuously were investigated before the renewal work of JMTR on FY 2007. The subjects of investigation were reactor building, primary cooling system tanks, secondary cooling system piping and tower, emergency generator and so on. As the result, it was confirmed that some facilities and machinery were necessary to repair and others were used continuously for long term by maintaining on the long-term maintenance plan. JMTR is planed to renew by the result of this investigation.
Kataoka, Shinichi*; Kitao, Hideo*; Tachikawa, Hirokazu*; Shimada, Takashi*; Maeda, Kazuto*; Nemoto, Kazuaki*; Yanagisawa, Ichiro*
PNC TJ1216 98-002, 676 Pages, 1998/02
None
Seki, Masami; Ikeda, Yoshitaka; Imai, Tsuyoshi; Ushigusa, Kenkichi; Naito, Osamu; Ide, Shunsuke; Kondoh, Takashi; Nemoto, Masahiro; Takeuchi, Hiroshi; Suganuma, Kazuaki; et al.
Proc. of the 19th European Conf. on Controlled Fusion and Plasma Physics, p.985 - 988, 1992/00
no abstracts in English
Ito, Tsuyoshi*; Tachi, Yukio; Nemoto, Kazuaki*; Sato, Tomofumi*; Takeda, Masaki; Ono, Hirokazu
no journal, ,
To validate the mass transfer model in sedimentary rocks, in-situ tracer test in rock matrix was conducted at rock matrix at 350 m deep drift in the Horonobe URL. The modeling results were evaluated to be reasonable by comparing in-situ and laboratory data.
Takeda, Masaki; Ishii, Eiichi; Ono, Hirokazu; Tachi, Yukio; Ito, Tsuyoshi*; Nemoto, Kazuaki*
no journal, ,
Tachi, Yukio; Takeda, Masaki; Ono, Hirokazu; Ito, Tsuyoshi*; Sato, Tomofumi*; Nemoto, Kazuaki*
no journal, ,
Terashima, Motoki; Beppu, Hikari*; Endo, Takashi*; Nemoto, Kazuaki*; Amano, Yuki
no journal, ,
no abstracts in English
Munemoto, Takashi; Omori, Kazuaki*; Iwatsuki, Teruki
no journal, ,
no abstracts in English
Amano, Yuki; Endo, Takashi; Nemoto, Kazuaki; Tachi, Yukio
no journal, ,
High-level radioactive waste (HLW) from nuclear power generation must be disposed in a safe manner for at least 100,000 years until the radiation dose is reduced to the levels of natural radiation dose in subsurface environments. Interaction of long-lived radionuclides with subsurface microorganisms has been studied to evaluate the effect of radionuclides migration in subsurface environments. However, the microbial activities and their mechanisms of radionuclide transformation are poorly understood. In this study, we investigated microbial populations stimulated by lanthanoids as analogue elements for actinides in natural systems. Groundwater samples collected from boreholes in the subsurface environment at Horonobe Underground Research Laboratory, Japan, were incubated anaerobically with lanthanoids. During the incubation experiments, concentrations of lanthanoids, total Fe, Fe, S
were measured by absorption spectrophotometry and ICP-MS. Microbial community compositions were analyzed by next generation sequencing the V4 region of the 16S rRNA gene on an Illumina Miseq. Phylogenetic analyses obtained from the original and incubated groundwaters revealed that microbial populations were changed from the original one. The original groundwater showed diverse microbial community structure with the dominant phylotypes clustered within the phylum Firmicutes, Proteobacteria, and Chloroflexi. In the lanthanoids added systems, microorganisms related to Chlostridium, Georgfuchsia or Rodobacter spp. increased by the incubation. These results indicate that interaction between microorganisms and actinides may effect on radionuclide migration in HLW systems.
Takeda, Masaki; Ono, Hirokazu; Ishii, Eiichi; Tachi, Yukio; Nemoto, Kazuaki*
no journal, ,
JAEA has developed evaluation techniques for characterization of solute transport in the mudstone through laboratory and in situ tests. This study reports on results of in situ tracer tests implemented for fractures in fault zone at Horonobe Underground Research Laboratory (URL).
Takahashi, Hiroaki; Nemoto, Kazuaki; Tachi, Yukio
no journal, ,
Ni(II) diffusion experiment and microstructure analysis in compacted water-saturated Na- and Ca-montmorillonite have been performed. Diffusion mechanism of Ni(II) in compacted montmorillonite has been studied by comparative analysis of Ni(II) diffusion profile, XRD analysis and XAFS analysis.