Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Mizuno, Rurie*; Niikura, Megumi*; Saito, Takeshi*; Matsuzaki, Teiichiro*; Sakurai, Hiroyoshi*; Amato, A.*; Asari, Shunsuke*; Biswas, S.*; Chiu, I.-H. ; Gianluca, J.*; et al.
Nuclear Instruments and Methods in Physics Research A, 1060, p.169029_1 - 169029_14, 2024/03
Times Cited Count：0 Percentile：0.02(Instruments & Instrumentation)Sakaki, Koji*; Kim, H.*; Majzoub, E. H.*; Machida, Akihiko*; Watanuki, Tetsu*; Ikeda, Kazutaka*; Otomo, Toshiya*; Mizuno, Masataka*; Matsumura, Daiju; Nakamura, Yumiko*
Acta Materialia, 234, p.118055_1 - 118055_10, 2022/08
Times Cited Count：9 Percentile：83.6(Materials Science, Multidisciplinary)Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.
Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03
Times Cited Count：43 Percentile：96.93(Astronomy & Astrophysics)Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 
C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.
Ino, Kohei*; Hernsdorf, A. W.*; Konno, Yuta*; Kozuka, Mariko*; Yanagawa, Katsunori*; Kato, Shingo*; Sunamura, Michinari*; Hirota, Akinari*; Togo, Yoko*; Ito, Kazumasa*; et al.
ISME Journal, 12(1), p.31 - 47, 2018/01
Times Cited Count：49 Percentile：91.33(Ecology)In this study, we found the dominance ofanaerobic methane-oxidizing archaea in groundwater enriched in sulfate and methane from a 300-m deep underground borehole in granitic rock.
Sasaki, Takayuki*; Kokami, Takayuki*; Kobayashi, Taishi*; Kirishima, Akira*; Murakami, Hiroaki; Amano, Yuki; Mizuno, Takashi; Iwatsuki, Teruki; Sasamoto, Hiroshi; Miyakawa, Kazuya
Journal of Nuclear Science and Technology, 54(3), p.373 - 381, 2017/03
Trace amounts of natural thorium and uranium in deep groundwater were investigated at two underground research laboratories situated at Horonobe and Mizunami, Japan. The groundwater was sampled from underground boreholes, and the colloid contribution was checked by in situ two size-fractionated ultrafiltration systems. A decrease in the concentration after in situ filtration suggested the presence of natural colloids and suspended matter that were carriers of a portion of the elements. The result of the Th and U concentrations in groundwater after 10 kDa filtration was analyzed thermodynamically using existing hydrogeological and geochemical data such as the mineral components in the groundwater at a given pH, ionic strength, concentration of co-existing ions, redox potential, and solid phase assumed. A crystalline solid phase made the solubility very low compared with that of the amorphous phase, and the solubility agreed well with the concentrations measured.
Ino, Kohei*; Konno, Yuta*; Kozuka, Mariko*; Hirota, Akinari*; Togo, Yoko*; Fukuda, Akari*; Komatsu, Daisuke*; Tsunogai, Urumu*; Tanabe, Akifumi*; Yamamoto, Satoshi*; et al.
Environmental Microbiology Reports (Internet), 8(2), p.285 - 294, 2016/04
Times Cited Count：26 Percentile：68.59(Environmental Sciences)To understand the subsurface biosphere, borehole investigation was conducted for 300-m deep granitic rocks at the Mizunami underground research laboratory, Japan. The initial biomass was the highest with the flourish of aerobic H
-oxidizing Hydrogenophaga spp., whereas an uncultivated lineage of the phylum Nitrospirae became predominant after three years with decreasing biomass. The common occurrence of many species of Nitrospirae and Chlorobi phyla at the geographically distinct sites and the exclusive detection of their phylogenetically related environmental sequences from deep groundwaters and terrestrial hot springs, suggest that these bacteria are indigenous and potentially adapted to the deep terrestrial subsurface.
Hama, Katsuhiro; Mizuno, Takashi; Sasao, Eiji; Iwatsuki, Teruki; Saegusa, Hiromitsu; Sato, Toshinori; Fujita, Tomoo; Sasamoto, Hiroshi; Matsuoka, Toshiyuki; Yokota, Hideharu; et al.
JAEA-Research 2015-007, 269 Pages, 2015/08
JAEA-Research-2015-007.pdf:68.65MBJAEA-Research-2015-007(errata).pdf:0.07MB
We have synthesised the research results from Mizunami/Horonobe URLs and geo-stability projects in the second mid-term research phase. It could be used as technical bases for NUMO/Regulator in each decision point from sitting to beginning of disposal (Principal Investigation to Detailed Investigation Phase). High quality construction techniques and field investigation methods have been developed and implemented and these will be directly applicable to the National Disposal Program (along with general assessments of hazardous natural events and processes). It will be crucial to acquire technical knowledge on decisions of partial backfilling and final closure by actual field experiments in Mizunami/Horonobe URLs as main themes for the next phases.
-semiquinone complex; A Possible dielectric response mechanismMitsumi, Minoru*; Ezaki, Kazunari*; Komatsu, Yuki*; Toriumi, Koshiro*; Miyato, Tatsuya*; Mizuno, Motohiro*; Azuma, Nobuaki*; Miyazaki, Yuji*; Nakano, Motohiro*; Kitagawa, Yasutaka*; et al.
Chemistry; A European Journal, 21(27), p.9682 - 9696, 2015/06
Times Cited Count：7 Percentile：25.07(Chemistry, Multidisciplinary)Suzuki, Yohei*; Konno, Yuta*; Fukuda, Akari*; Komatsu, Daisuke*; Hirota, Akinari*; Watanabe, Katsuaki*; Togo, Yoko*; Morikawa, Noritoshi*; Hagiwara, Hiroki; Aosai, Daisuke*; et al.
PLOS ONE (Internet), 9(12), p.e113063_1 - e113063_20, 2014/12
Times Cited Count：12 Percentile：34.33(Multidisciplinary Sciences)We present multi-isotopic evidence of microbially mediated sulfate reduction in a granitic aquifer, a representative of the terrestrial crust habitat. Deep groundwater of meteoric origin was collected from underground boreholes drilled into the Cretaceous Toki granite, central Japan. A large sulfur isotopic fractionation of 20-60 permil diagnostic to microbial sulfate reduction is associated with the investigated groundwater containing sulfate below 0.2 mM. In contrast, a small carbon isotopic fractionation (
30 permil) is not indicative of methanogenesis. Our results demonstrate that the deep biosphere in the terrestrial crust is metabolically active and playing a crucial role in the formation of reducing groundwater even under low energy fluxes.
Aosai, Daisuke*; Yamamoto, Yuhei*; Mizuno, Takashi; Ishigami, Toru*; Matsuyama, Hideto*
Colloids and Surfaces A; Physicochemical and Engineering Aspects, 461, p.279 - 286, 2014/11
Times Cited Count：10 Percentile：25(Chemistry, Physical)In studies of colloids in deep groundwater, a serious problem exists because the properties of the colloids are influenced by changes in the chemistry of groundwater upon exposure to the atmosphere and pressure release during sampling. Then, ultrafiltration technique, while maintaining in situ hydrochemical conditions was developed. As the result of the investigation using the method at the Mizunami underground Research Laboratory (MIU), different types of colloids consisting of inorganic and organic substances were observed and complex formation between the colloids and REEs was suggested. Furthermore, characteristic partitioning of REEs depending on colloids size was observed in complex natural environments without chemical disturbance. The current findings are useful for understanding migration of radionuclides.
Shigyo, Nobuhiro*; Uozumi, Yusuke*; Uehara, Haruhiko*; Nishizawa, Tomoya*; Mizuno, Takafumi*; Takamiya, Masanori*; Hashiguchi, Taro*; Satoh, Daiki; Sanami, Toshiya*; Koba, Yusuke*; et al.
Nuclear Data Sheets, 119, p.303 - 306, 2014/05
Times Cited Count：0 Percentile：0.02(Physics, Nuclear)Heavy ion cancer therapy has been increased by reason of its clinical advantages. During the treatment, the secondary particles such as neutron and 
-ray are produced by nuclear reactions of a heavy ion incidence on a nucleus in a patient body. Estimation of the secondary neutrons yields data is essential for assessment of radiation safety on both of workers and public in treatment facilities. We have measured the neutron yields from carbon ion incidence on carbon, nitrogen and oxygen targets in wide angular range from 15 to 90 with 100- and 290-MeV/u.
Fukushi, Keisuke*; Hasegawa, Yusuke*; Maeda, Koshi*; Aoi, Yusuke*; Tamura, Akihiro*; Arai, Shoji*; Yamamoto, Yuhei*; Aosai, Daisuke*; Mizuno, Takashi
Environmental Science & Technology, 47(22), p.12811 - 12818, 2013/11
Times Cited Count：27 Percentile：58.19(Engineering, Environmental)Eu(III) sorption on granite was examined by the combined microscopic and macroscopic approaches. Polished thin sections of the granite were reacted with solutions containing 10 
M of Eu(III) and analyzed using EPMA and LA-ICP-MS. The Eu enrichment up to 6 wt.% was observed on most of the biotite grains. The Eu-enriched parts commonly lose K, which is the interlayer cation of biotite, indicating that the sorption mode is cation exchange in the interlayer. Batch Eu(III) sorption experiments on granite and biotite powders were conducted. The macroscopic sorption behavior of biotite was consistent with that of granite. The obtained sorption edges can be reproduced reasonably by the modeling considering single-site cation exchange reactions. Granite is complex mineral assemblages. However, the combined microscopic and macroscopic approaches revealed that elementary reactions by single phase can be representative for the bulk sorption reaction in complex mineral assemblages.
Shigyo, Nobuhiro*; Uozumi, Yusuke*; Uehara, Haruhiko*; Nishizawa, Tomoya*; Mizuno, Takafumi*; Satoh, Daiki; Sanami, Toshiya*; Koba, Yusuke*; Takada, Masashi*; Matsufuji, Naruhiro*
JAEA-Conf 2013-002, p.137 - 142, 2013/10
Heavy ion cancer therapy has been increased by reason of its clinical advantages. During the treatment, the secondary particles such as neutron and -ray are produced by nuclear reactions of a heavy ion incidence on a nucleus in a patient body. Estimation of double differential cross sections of secondary neutron is important to risk assessment of extra dose to organs in the vicinity of the irradiated tumor. Accurate data in neutron energy around 1 MeV is required because neutron in the energy region has large relative biological effectiveness. Neutron double differential cross sections by inducing 290 MeV/u carbon ion to bio-elements have been obtained experimentally. In order to have knowledge of neutron production by deceleration carbon in a human body, we measured the neutron yields from carbon ion incidence on a carbon target of neutron energy below 1 MeV in wide angular range from 15 to 90 with 100 MeV/u.
Uozumi, Yusuke*; Shigyo, Nobuhiro*; Uehara, Haruhiko*; Nishizawa, Tomoya*; Mizuno, Takafumi*; Satoh, Daiki; Sanami, Toshiya*; Koba, Yusuke*; Takada, Masashi*; Matsufuji, Naruhiro*; et al.
HIMAC-140, p.234 - 235, 2013/08
In the heavy-ion radiotherapy, considerable discussion has been attracted regarding the potential for second cancer induction by secondary neutrons produced from the primary heavy-ion fragmentation. We have started new measurements at 100 MeV/u to investigate the neutron production by heavy ions decelerating in a patient body.
Shimo, Michito*; Kumamoto, So*; Tsuyuguchi, Koji; Onoe, Hironori; Saegusa, Hiromitsu; Mizuno, Takashi; Oyama, Takuya
JAEA-Research 2012-043, 98 Pages, 2013/03
JAEA-Research-2012-043.pdf:26.71MB
One of the goals of the Mizunami Underground Research Laboratory (MIU) Project is to develop technical basis for investigation, analysis and evaluation technologies for understanding the deep underground geological environment in various scales. Understanding groundwater flow system is one of the important issues in the project, and to achieve this purpose, technologies for hydrogeological model and groundwater flow simulation technique, have to be established. As a result of this study, the significant hydrogeological structures around the MIU Construction Site were estimated. The inflow rate into the MIU facilities and hydraulic and geochemical impacts around the MIU Construction Site caused by the MIU facilities construction were predicted. The effect of pre-grouting to the MIU facilities was also confirmed.
Mizuno, Takashi; Aosai, Daisuke; Shingu, Shinya; Hagiwara, Hiroki; Yamamoto, Yuhei; Fukuda, Akari
Nihon Genshiryoku Gakkai Wabun Rombunshi, 12(1), p.89 - 102, 2013/03
no abstracts in English
Kunimaru, Takanori; Mikake, Shinichiro; Nishio, Kazuhisa; Tsuruta, Tadahiko; Matsuoka, Toshiyuki; Ishibashi, Masayuki; Ueno, Takashi; Tokuyasu, Shingo; Daimaru, Shuji; Takeuchi, Ryuji; et al.
JAEA-Review 2012-020, 178 Pages, 2012/06
JAEA-Review-2012-020.pdf:33.16MB
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 Phase III started in 2010 fiscal year. This report shows the results of the investigation, construction and collaboration studies in fiscal year 2010, as a part of the Phase II based on the MIU Master Plan updated in 2002.
Hagiwara, Hiroki; Shingu, Shinya; Kurita, Kazuaki*; Eguchi, Keita*; Horita, Masakuni*; Mizuno, Takashi
JAEA-Data/Code 2012-005, 67 Pages, 2012/06
JAEA-Data-Code-2012-005.pdf:3.42MB
JAEA-Data-Code-2012-005-appendix(CD-ROM).zip:0.74MB
Japan Atomic Energy Agency has been carried out investigations to understand the fluctuation of groundwater chemistry related to the shafts excavation at the Mizunami Underground Research Laboratory in Mizunami City, Gifu prefecture, Japan. The data for pore water pressure, water temperature and groundwater chemistry have been provided from two surface-based boreholes, MSB-2 and MSB-4 boreholes, installed a modular multilevel groundwater monitoring system (MP system). The monitoring has been conducted once in a month since April 2003. According to the results, the shaft excavation has caused drawdown of the hydraulic head and change in the groundwater chemistry in the MIU construction site. In this report, the data of monitoring at the MSB-2 and the MSB-4 boreholes from April 2010 to March 2011 were compiled. In addition, the monitoring results at the DH-2 borehole as part of Regional Hydrogeological Study project, are summarized as an appendix.
Shingu, Shinya; Hagiwara, Hiroki; Masuda, Kaoru*; Iizuka, Masatoshi*; Inui, Michiharu*; Mizuno, Takashi
JAEA-Data/Code 2012-003, 50 Pages, 2012/06
JAEA-Data-Code-2012-003.pdf:4.61MBJAEA-Data-Code-2012-003-appendix(CD-ROM).zip:226.3MB
Japan Atomic Energy Agency has been investigated the groundwater chemistry on excavating the underground facilities as part of the Mizunami Underground Research Laboratory (MIU) Project at Mizunami City, Gifu Prefecture, Japan. This report compiles data set of the groundwater chemistry obtained at MIU in the fiscal year 2010. In terms of ensuring traceability of data, basic information (e.g. sampling location, sampling date, sampling method, analytical method) and methodology for quality control is described.
Maruyama, Shuhei; Oki, Shigeo; Okubo, Tsutomu; Kawashima, Katsuyuki; Mizuno, Tomoyasu
Journal of Nuclear Science and Technology, 49(6), p.640 - 654, 2012/06
Times Cited Count：3 Percentile：24.98(Nuclear Science & Technology)This study shows the good correlations in FBR core characteristics, and find out the mechanism of their correlations with the aid of sensitivity analyses. It has been clarified that Doppler coefficient turns to have the correlations with the other core characteristics by considering the constraint of the criticality requirement for fuel composition variations. The finding of the correlations makes easy to specify the ranges of core reactivity control and core safety properties which are important for core design in determining core specification and performance. It gives significant information for FBR core design in the transition stage. Moreover, as an application of the above-mentioned correlations, a simplified burnup reactivity index is developed for rapid and rational estimation of the core characteristic variations. By using this index and the correlations, the core characteristic variations can be estimated for various fuel compositions without repeating core calculations.
