Rare earth elements (REE) in deep groundwater from granite and fracture-filling calcite in the Tono area, central Japan; Prediction of REE fractionation in paleo- to present-day groundwater

Munemoto, Takashi; Omori, Kazuaki*; Iwatsuki, Teruki

Chemical Geology, 417, p.58 - 67, 2015/12

https://doi.org/10.1016/j.chemgeo.2015.09.024

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).

Mizunami Underground Research Laboratory Project, Annual report for fiscal year 2013

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

JAEA-Review-2014-038.pdf:162.61MB

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.

Methodology development for colloid investigation in groundwater

Omori, Kazuaki; Munemoto, Takashi; Hasegawa, Takashi; Shingu, Shinya*; Hagiwara, Hiroki; Iwatsuki, Teruki

JAEA-Research 2014-013, 29 Pages, 2014/08

JAEA-Research-2014-013.pdf:48.04MB

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.

XAFS analysis of Ni diffused in compacted bentonite

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

http://www.ritsumei.ac.jp/acd/re/src/kyoyo/seikahoukoku2012/R1228.pdf

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.

The Outline of investigation on integrity of JMTR concrete structures, cooling system and utility facilities

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

JAEA-Technology-2009-030.pdf:69.18MB

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.

The Distant coupling of LHCD launcher in the JT-60U

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

Evaluating the mass transport characteristics for fault zone in mudstone at the Horonobe Underground Research Laboratory

Takeda, Masaki; Ishii, Eiichi; Ono, Hirokazu; Tachi, Yukio; Ito, Tsuyoshi*; Nemoto, Kazuaki*

no journal, , 

Distribution coefficients of rare earth elements to microorganisms including uncultivated species in deep sedimentary groundwater

Terashima, Motoki; Beppu, Hikari*; Endo, Takashi*; Nemoto, Kazuaki*; Amano, Yuki

no journal, , 

no abstracts in English

Microbial populations stimulated by lanthanoids in groundwater of Pliocene diatomaceous mudstone of northernmost Japan

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.

Study of Ni diffusion mechanisms on compacted montmorillonite

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.