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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*; 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.
Fujita, Masaki*; Frost, C. D.*; Bennington, S. M.*; Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Mizuno, Fumio*; Ikeuchi, Kazuhiko*; Arai, Masatoshi
Journal of the Physical Society of Japan, 82(8), p.084708_1 - 084708_5, 2013/08
Times Cited Count：1 Percentile：11.42(Physics, Multidisciplinary)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:4.61MB
JAEA-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.
Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Mizuno, Fumio; Nakajima, Kenji; Kawamura, Seiko; Yokoo, Tetsuya*; Nakatani, Takeshi; Maruyama, Ryuji; Soyama, Kazuhiko; et al.
Journal of the Physical Society of Japan, 80(Suppl.B), p.SB025_1 - SB025_6, 2011/01
Times Cited Count：102 Percentile：94.01(Physics, Multidisciplinary)Sai, Masataka; Hagiwara, Hiroki; Matsushima, Hiroyuki*; Noda, Masatoshi*; Noda, Masaru*; Ando, Kenichi*; Tanaka, Tatsuya*; Ueda, Tadashi*; Honda, Yuko*; Mizuno, Takashi
JAEA-Data/Code 2010-010, 75 Pages, 2010/09
JAEA-Data-Code-2010-010.pdf:2.5MB
This report compiles data set of the groundwater chemistry obtained at Mizunami Underground Research Laboratory (MIU) between the fiscal year 2004 and the fiscal year 2007. These data includes groundwater chemistry of inflow in the shafts and sampled groundwater in the boreholes, which drilled from sub-stages of MIU and from surface (MSB-2, MSB-4, and MIZ-1). Basic information (e.g. sampling location, sampling date, sampling method, analytical method) are also described in terms of quality control and traceability.
Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Mizuno, Fumio; Yokoo, Tetsuya*; Nakatani, Takeshi; Arai, Masatoshi; Fujita, Masaki*
Kotai Butsuri, 45(2), p.79 - 89, 2010/02
Inelastic neutron scattering measurement using multiple incident energies can drastically enhances the measurement efficiency. The article reviews the principle of this new technique and an example of the measurement using the chopper spectrometer 4SEASONS of the pulsed neutron experimental facility in Japan Proton Accelerator Research Complex (J-PARC).
Okano, Yasushi; Kobayashi, Noboru*; Ogawa, Takashi; Oki, Shigeo; Naganuma, Masayuki; Okubo, Tsutomu; Mizuno, Tomoyasu; Ogata, Takanari*; Ueda, Nobuyuki*; Nishimura, Satoshi*
JAEA-Research 2009-025, 105 Pages, 2009/10
JAEA-Research-2009-025.pdf:10.45MB
A metal fuel core has specific features on high heavy metal density, hard neutron spectrum, and efficient neutron utilization. Enlarged applicable design envelops would improve core performances and features: higher breeding ratio, compacted reactor core, and, smaller amount of Pu-fissile inventory. A joint study on "Reactor Core and Fuel Design of Metal Fuel Core of Sodium Cooled Fast Reactor" by Japan Atomic Energy Agency and Central Research Institute of Electric Power Industry has been conducted during Japanese fiscal years of 2007 and 2008. This report shows the results on (1) the study on applicable design ranges of metal fuel specifications, (2) the study on conceptual core designs for high breeding ratio, and (3) the safety study on metal fuel core designed in the Fast Reactor Cycle Technology Development (FaCT) Project.
Nakamura, Mitsutaka; Kajimoto, Ryoichi; Inamura, Yasuhiro; Mizuno, Fumio; Fujita, Masaki*; Yokoo, Tetsuya*; Arai, Masatoshi
Journal of the Physical Society of Japan, 78(9), p.093002_1 - 093002_4, 2009/09
Times Cited Count：115 Percentile：94.76(Physics, Multidisciplinary)We succeeded in experimentally demonstrating that a series of two-dimensional maps of a dynamical structure factor in momentum-energy space with multiple incident energies can be simultaneously obtained by one measurement. This method reduces the dead time of time-of-flight measurement, and thus it markedly increases the measurement efficiency. Our achievement realized using the Fermi chopper spectrometer 4SEASONS in J-PARC is expected to open up new possibilities of inelastic neutron scattering measurements.
Hanamuro, Takahiro; Saito, Hiroshi; Asamori, Koichi; Iyatomi, Yosuke; Tsuruta, Tadahiko; Yabuuchi, Satoshi; Mizuno, Takashi; Sato, Toshinori; Nakatsuka, Noboru; Shigeta, Naotaka; et al.
JNC TN7400 2004-010, 173 Pages, 2004/12
JNC-TN7400-2004-010.pdf:41.03MB
Japan Nuclear Cycle Development Institute. (JNC) is developing two underground research laboratory projects; the Mizunami Underground Research Laboratory(MIU) Project for crystalline rock,.at Tono Geoscience Center (TGC) and the Horonobe Underground Research Laboratory ・Project for・ sedimentary rock at the Horonobe Underground Research Center. Both projects are intended for research and development of geological disposal technology for high-level radioactive wastes. At this time, these two underground research laboratory projects are advancing to the Construction Phase (Phase II) from the Surface-based Investigation Phase (Phase I). Therefore it was considered appropriate for JNC to hold an international conference to introduce the two underground research laboratory projects and R&D results from Phase I, to have presentations on overseas URLs, to exchange opinions by researchers in each field of research and to reflect the conference outcome in a future R&D plan. The Conference was held in two parts. Part 1, the "International Conference on Geoscientific Study in Mizunami '04 (ICGM '04)" featured the MIU Project and the Regional Hydrogeological Study Project performed by TGC. It was held in Mizunami City at the Sogo Bunka Center from October 21st to 22nd. In Part 2, the "International Workshop on Horonobe Underground Research Laboratory Project", featured the Horonobe Underground Research Laboratory Project performed by the Horonobe Underground Research Center. It was held at Horonobe Town Hall from, October 25th to 26th 2004. This Technical Report documents the ICGM'04 program, abstracts of presentations and slides and transcription of "Panel Discussions II and "Summary of the Conference"
Konomura, Mamoru; Ogawa, Takashi; Okano, Yasushi; Yamaguchi, Hiroyuki; Murakami, Tsutomu; Takaki, Naoyuki; Nishiguchi, Youhei; Sugino, Kazuteru; Naganuma, Masayuki; Hishida, Masahiko; et al.
JNC TN9400 2004-035, 2071 Pages, 2004/06
JNC-TN9400-2004-035.pdf:76.42MB
The attractive concepts for Sodium-, lead-bismuth-, helium- and water-cooled FBRs have been created through using typical plant features and employing advanced technologies. Efforts on evaluating technological prospects of feasibility have been paid for these concepts. Also, it was comfirmed if these concepts satisfy design requierments of capability and performance presumed in the feasibilty study on commertialization of Fast Breeder Reactor Systems. As results, it was concluded that the selection of sodium-cooled reactor was most rational for practical use of FBR technologies in 2015.
Yamano, Hidemasa; Fujita, Satoshi; Tobita, Yoshiharu; Kamiyama, Kenji; Kondo, Satoru; Morita, Koji*; Fischer, E. A.; Brear, D. J.; Shirakawa, Noriyuki*; Cao, X.; et al.
JNC TN9400 2003-071, 340 Pages, 2003/08
JNC-TN9400-2003-071.pdf:1.54MB
An advanced safety analysis computer code, SIMMER-III, has been developed to investigate postulated core disruptive accidents in liquid-metal fast reactors (LMFRs). SIMMER-III is a two-dimensional, three-velocity-field, multiphase, multicomponent, Eulerian, fluid-dynamics code coupled with a space-dependent neutron kinetics model. By completing and integrating all the physical models originally intended at the beginning of this code development project, SIMMER-III is now applicable to integral reactor calculations and other complex multiphase flow problems. A systematic code assessment program, conducted in collaboration with European research organizations, has shown that the advanced features of the code have resolved many of the limitations and problem areas in the previous SIMMER-II code. In this report, the models, numerical algorithms and code features of SIMMER-III Version 3.A are described along with detailed program description. Areas which require future model refinement are also discussed. SIMMER-III Version 3.A, a coupled fluid-dynamics and neutronics code system, is expected to significantly improve the flexibility and reliability of LMFR safety analyses.
Yamano, Hidemasa; Fujita, Satoshi; Tobita, Yoshiharu; Kondo, Satoru; Morita, Koji*; Sugaya, Masaaki*; Mizuno, Masahiro*; Hosono, Seigo*; Kondo, Teppei*
JNC TN9400 2003-070, 333 Pages, 2003/08
JNC-TN9400-2003-070.pdf:1.35MB
An advanced safety analysis computer code, SIMMER-III, has been developed at Japan Nuclear Cycle Development Institute (JNC) to more realistically investigate postulated core disruptive accidents in liquid-metal fast reactors. The two-dimensional framework of SIMMER-III fluid dynamics has been extended to three dimensions to a new code, SIMMER-IV, which is currently (in Version 2) coupled with the three-dimensional neutronics model. With the completion of the SIMMER-IV version, the applicability of the code is further enhanced and the many of the known limitations in SIMMER-III are eliminated. The sample calculations demonstrated the general validity of SIMMER-IV. This report describes SIMMER-IV Version 2.A, by documenting the models, numerical algorithms and code features, along with the program description and input and output information to aid the users.
kondo, Satoru; Yamano, Hidemasa; Tobita, Yoshiharu; Fujita, Satoshi; Morita, Koji*; Mizuno, Masahiro*; *
JNC TN9400 2001-003, 307 Pages, 2000/11
JNC-TN9400-2001-003.pdf:8.33MB
An advanced safety analysis computer code, SIMMER-III, has been developed at Japan Nuclear Cycle Development Institute (JNC) to more realistically investigate postulated core disruptive accidents in liquid-metal fast reactors. The two-dimensional framework of SIMMER-III fluid dynamics has been extended to three dimensions to a new code, SIMMER-IV, which is currently (in Version 1) coupled with the existing two-dimensional neutronics model. With the completion of the first SIMMER-IV version, the applicability of the code is further enhanced and the many of the known limitations in SIMMER-III are eliminated. The sample calculations demonstrated the general validity of SIMMER-IV. This report describes SIMMER-IV version 1.B, by documenting the models, numerical algorithms and code features, along with the program description and input and output information to aid the users. Further extension of the code is planned to couple the three-dimensional neutronics in the future.
ion source for the JT-60U negative-ion-based neutral beam injectorOkumura, Yoshikazu; Hanada, Masaya; Inoue, Takashi; Kuriyama, Masaaki; Maeno, Shuichi*; Matsuoka, Mamoru; Miyamoto, Kenji; Mizuno, Makoto; Ohara, Yoshihiro; Suzuki, Satoshi; et al.
Proceedings of 15th IEEE/NPSS Symposium on Fusion Engineering, p.466 - 469, 1993/00
no abstracts in English
Yamamoto, Shin; Ohara, Yoshihiro; Tani, Keiji; Nishio, Satoshi; Okumura, Yoshikazu; Araki, Masanori; Azumi, Masafumi; R.S.Devoto*; Fujisawa, Noboru; Hitoki, Shigehisa*; et al.
JAERI-M 88-086, 183 Pages, 1988/05
no abstracts in English
Kajimoto, Ryoichi; Nakamura, Mitsutaka; Yokoo, Tetsuya*; Nakajima, Kenji; Inamura, Yasuhiro; Takahashi, Nobuaki; Maruyama, Ryuji; Soyama, Kazuhiko; Shibata, Kaoru; Suzuya, Kentaro; et al.
no journal, ,
4SEASONS is one of the neutron chopper spectrometers in J-PARC/MLF. It is intended to provide very high counting rate up to 300 meV neutron energy with medium resolution (
% at 
) to efficiently collect weak inelastic signals from novel spin and lattice dynamics especially in high-
superconductors and related materials. To achieve this goal, the spectrometer equips advanced instrumental design such as an elliptic-shaped converging neutron guide coated with high-
(
-4) supermirror, long-length (2.5 m) 
He PSDs arranged cylindrically inside the vacuum scattering chamber. Furthermore, the spectrometer is ready for multi-incident-energy measurements by the repetition rate multiplication method with a special Fermi chopper, and polarization analysis with He spin filters. 4SEASONS is now under construction and will be ready to use in December 2008. In this paper, we show the design of 4SEASONS and current status of its construction.
Kajimoto, Ryoichi; Yokoo, Tetsuya*; Nakamura, Mitsutaka; Nakajima, Kenji; Inamura, Yasuhiro; Takahashi, Nobuaki; Maruyama, Ryuji; Soyama, Kazuhiko; Mizuno, Fumio; Shibata, Kaoru; et al.
no journal, ,
no abstracts in English
Kajimoto, Ryoichi; Yokoo, Tetsuya*; Nakamura, Mitsutaka; Nakajima, Kenji; Inamura, Yasuhiro; Takahashi, Nobuaki; Maruyama, Ryuji; Soyama, Kazuhiko; Mizuno, Fumio; Shibata, Kaoru; et al.
no journal, ,
no abstracts in English
Kajimoto, Ryoichi; Nakamura, Mitsutaka; Yokoo, Tetsuya*; Inamura, Yasuhiro; Mizuno, Fumio; Nakajima, Kenji; Takahashi, Nobuaki; Kawamura, Seiko; Maruyama, Ryuji; Soyama, Kazuhiko; et al.
no journal, ,
no abstracts in English
