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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：44 Percentile：97.1(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.
Kutsuna, Hideki; Kadowaki, Haruhiko; Sakakibara, Yasuhide; Hirata, Tomohiro
JAEA-Review 2013-027, 40 Pages, 2013/09
JAEA-Review-2013-027.pdf:7.42MB
Fugen Decommissioning Engineering Center is establishing "Technical special committee on Fugen decommissioning" which consists of the members well-informed, aiming to make good use of Fugen as a place for technological development, as the central point in the energy research and development base making project of Fukui prefecture. This report compiles presentation materials "The Current Situation of Fugen Decommissioning", "Upgrading of a Removal Technique for a Heavy Water Withdraw and a Tritium Removal" and "Research of Ageing Management of Nuclear Power Plant for Safe Long Term Operating in Fukui", "The Work for Solution and Promotion on Technical Challenge (Public Offering Type)" which is related with the efforts of Fugen in the Fukui energy research and development centralization plan, presented in the 27th Technical special committee on Fugen decommissioning which was held on March 14, 2013.
Motojima, Osamu*; Yamada, Hiroshi*; Komori, Akio*; Oyabu, Nobuyoshi*; Muto, Takashi*; Kaneko, Osamu*; Kawahata, Kazuo*; Mito, Toshiyuki*; Ida, Katsumi*; Imagawa, Shinsaku*; et al.
Nuclear Fusion, 47(10), p.S668 - S676, 2007/10
Times Cited Count：34 Percentile：73.64(Physics, Fluids & Plasmas)The performance of net-current free heliotron plasmas has been developed by findings of innovative operational scenarios in conjunction with an upgrade of the heating power and the pumping/fuelling capability in the Large Helical Device (LHD). Consequently, the operational regime has been extended, in particular, with regard to high density, long pulse length and high beta. Diversified studies in LHD have elucidated the advantages of net-current free heliotron plasmas. In particular, an internal diffusion barrier (IDB) by a combination of efficient pumping of the local island divertor function and core fuelling by pellet injection has realized a super dense core as high as 5
10
m
, which stimulates an attractive super dense core reactor. Achievements of a volume averaged beta of 4.5% and a discharge duration of 54 min with a total input energy of 1.6 GJ (490 kW on average) are also highlighted. The progress of LHD experiments in these two years is overviewed by highlighting IDB, high-beta and long pulse.
Hara, Tomohiro*; Oba, Ryoji*; Okabayashi, Kazuki*; Yoneda, Jiro*; Nagai, Haruyasu; Hayashi, Takashi*
Proceedings of International Workshop on Physical Modelling of Flow and Dispersion Phenomena (PHYSMOD 2007), p.167 - 174, 2007/08
We simulated a meandering effect of wind direction fluctuation on horizontal gas diffusion over Mt. Tsukuba, using a rotating turntable in the wind tunnel experiment. Experimental results were validated with field data observed by Japan Atomic Energy Research Institute (JAERI), 1989 and 1990. We also simulated actual unsteady phenomena of airflow and gas diffusion over Mt. Tsukuba, and compared the calculated results with field data. Both data agreed well under neutral, stable and unstable atmospheric stabilities.
Motojima, Osamu*; Yamada, Hiroshi*; Komori, Akio*; Oyabu, Nobuyoshi*; Kaneko, Osamu*; Kawahata, Kazuo*; Mito, Toshiyuki*; Muto, Takashi*; Ida, Katsumi*; Imagawa, Shinsaku*; et al.
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 12 Pages, 2007/03
The performance of net-current free Heliotron plasmas has been developed by findings of innovative operational scenarios in conjunction with an upgrade of the heating power and the pumping/fueling capability in the Large Helical Device (LHD). Consequently, the operational regime has been extended, in particular, with regard to high density, long pulse length and high beta. Diversified studies in LHD have elucidated the advantages of net-current free heliotron plasmas. In particular, an Internal Diffusion Barrier (IDB) by combination of efficient pumping of the local island divertor function and core fueling by pellet injection has realized a super dense core as high as 510m, which stimulates an attractive super dense core reactor. Achievements of a volume averaged beta of 4.5 % and a discharge duration of 54-min. with a total input energy of 1.6 GJ (490 kW in average) are also highlighted. The progress of LHD experiments in these two years is overviewed with highlighting IDB, high 
and long pulse.
Oku, Takayuki; Suzuki, Junichi; Sasao, Hajime*; Yamada, Satoru; Furusaka, Michihiro*; Adachi, Tomohiro*; Shinohara, Takenao*; Ikeda, Kazuaki*; Shimizu, Hirohiko
Physica B; Condensed Matter, 356(1-4), p.126 - 130, 2005/02
Times Cited Count：11 Percentile：45.41(Physics, Condensed Matter)We have developed a magnetic neutron lens (MNL) based on a sextupole magnet. A neutron beam, which is incident to the sextupole magnet, either converges or diverges depending on the neutron spin state. Small-angle neutron scattering in focusing geometry (FSANS) was proposed to improve the q-resolution and/or measuring efficiency. The MNL is considered to be the most suitable focusing device for FSANS experiments using a polarized neutron beam, since it focuses the polarized neutron beam free from neutron attenuation and scattering by substances. Recently, we have developed the MNLs with sufficiently large apertures and strong focusing power for FSANS experiments. In this study, we evaluate the focusing property of the MNLs for the polarized neutron beam, and performed FSANS experiments using the MNL. The obtained results are discussed.
Oku, Takayuki; Suzuki, Junichi; Sasao, Hajime*; Adachi, Tomohiro*; Shinohara, Takenao*; Ikeda, Kazuaki*; Morishima, Takahiro*; Sakai, Kenji*; Kiyanagi, Yoshiaki*; Furusaka, Michihiro*; et al.
Nuclear Instruments and Methods in Physics Research A, 529(1-3), p.116 - 119, 2004/08
Times Cited Count：21 Percentile：77.76(Instruments & Instrumentation)As a neutron has a magnetic dipole moment, it is accelerated in a magnetic field gradient. Thus, we can control a neutron trajectory free from neutron beam attenuation and scattering using the magnetic field gradient. A sextupole magnetic field functions as a neutron focusing and defocusing lens depending on the neutron spin state. The neutron focusing effect was experimentally verified using a 6-piece permanent sextupole magnet. For the application in practical neutron scattering experiments, a sextupole magnet with a sufficiently large aperture accompanied with strong focusing power is demanded. Recently, a superconducting sextupole magnet, a Halbach-type permanent sextupole magnet and a sextupole pulse electro-magnet have been developed in a project of the development and application of neutron optics. These magnets will be dedicated to practical uses in neutron scattering experiments. In this paper, current status of the development of the magnetic neutron lenses is reported, and their application in the neutron scattering experiments is discussed.
Shinohara, Kunihiko; Asano, Tomohiro; Momose, Takumaro; Takeishi, Minoru; Kobayashi, Hirohide; Oka, Tsutomu; Takasaki, Koji
JNC TN8440 2003-020, 125 Pages, 2003/09
JNC-TN8440-2003-020.pdf:11.14MB
This annual report summarizes the activities of the Radiation Protection Division at JNC Tokai Works in fiscal 2002.The Tokai Works undertakes various research and development for the reprocessing of spent fuel, plutonium fuel fabrication, fast reactor fuel recycling technology, and radioactive waste treatment and disposal, all of which are done under strict safety management.The major radiation facilities in the Tokai Works are the Tokai Reprocessing Plant (TRP), which has been in operation since 1977, three MOX fuel fabrication facilities, the first of which has been in operation since 1965, the Chemical Processing Facility (CPF) where fast reactor (FR) reprocessing technologies are being developed, and various other radioisotope and uranium research laboratories.The Radiation Protection Division is responsible for radiation control in and around these facilities, including personnel monitoring, workplace monitoring, consultation on radiological work planning and evaluation, monitoring of gas and liquid waste effluents, environmental monitoring, instrumentation, calibration, quality assurance, and safety research. The Division also provides technical support and cooperation to other international and domestic institutes in the radiation protection field.In fiscal 2002, the results of radiological monitoring showed the situation to be normal, and no radiological incident or accident occurred. The maximum annual effective dose to radiation workers was 6.5 mSv and the mean annual effective dose was 0.1 mSv. Individual doses were kept within the annual dose limit specified in the safety regulations. The estimated effective dose caused by gas and liquid effluents from the TRP to members of the public around the Tokai Works was 4.2 * 10
mSv. Environmental monitoring and effluent control were performed appropriately in compliance with safety regulation and standards.
Shinohara, Kunihiko*; Asano, Tomohiro; Narita, Osamu
PNC TN8410 87-17, 40 Pages, 1987/05
A computer code ORION-II has been developed to estimate environmental concentration and dose due to airborne release of radioactive material from multiple sources of nuclear fuel cycle facilities. The modified Gaussian plume model is applied to calculate atmospheric dispersion. The plume depletion models such as gravitational settling, dry deposition, precipitation scavenging and radioactive decay are considered as the causes of the depletion and deposition on the ground and vegetation. Dose to the public is calculated as an individual dose. Inhalation and oral intake are considered as internal pathways. Submersion in the radioactive cloud and external exposure to ground surface contamination are considered as external pathways. ORION-II is the updated version of ORION code (PNCT N841-83-42) and is appricable to the case study of environmental assessment for the nuclear fuel cycle facilities. ORION-II is written in FORTRAN-IV language and can be run on IBM 360, 370, 303X, 308X, 43XX, and FACOM M-series computers.
Kitahara, Yoshihisa*; Ishida, Junichiro; Asano, Tomohiro
PNC TN8440 87-008, 155 Pages, 1987/02
The environmental radiation monitoring around the Tokai Reprocessing Plant has been performed since 1975, based on "Safety Standard for the Tokai Reprocessing Plant, Chapter V - Environmental Monitoring". This annual report presents interpretation of the results of the environmental monitoring and the results of dose estimation to the hypothetical inhabitants due to the annual discharges of the radioactivity from the reprocessing plant during 1986. Notes of this year may be the detection of the radioactivities in various kinds of samples following the accident at Chernobyl nuclear power plant. Appendix presents comprehensive information, such as, monitoring program, monitoring results, meteorological data, annual discharges from the plant and results of dose estimation.
Iwai, Makoto; *; Asano, Tomohiro; Shinohara, Kunihiko*
PNC TN841 85-10, 95 Pages, 1985/04
no abstracts in English
*; Asano, Tomohiro; *; Shinohara, Kunihiko*; *; Miura, Makoto
PNC TN841 83-08, 69 Pages, 1983/02
no abstracts in English
Miura, Makoto; Narita, Osamu; Shinohara, Kunihiko*; Asano, Tomohiro
PNC TN843 81-08, 240 Pages, 1981/09
None
Kitahara, Yoshihisa*; Narita, Osamu; Asano, Tomohiro; Kishimoto, Yoichiro; *
PNC TN841 81-44, 73 Pages, 1981/08
no abstracts in English
Kitahara, Yoshihisa*; Narita, Osamu; Asano, Tomohiro; *
PNC TN841 81-01, 97 Pages, 1981/01
no abstracts in English
Kitahara, Yoshihisa*; Narita, Osamu; Shinohara, Kunihiko; Asano, Tomohiro; Kitahara, Yoshihisa
Hoken Butsuri, 16, p.151 - 163, 1981/00
Watanabe, Kiyomasa*; Suzuki, Yasuhiro*; Yamaguchi, Taiki; Narihara, Kazumichi*; Tanaka, Kenji*; Tokuzawa, Tokihiko*; Yamada, Ichihiro*; Sakakibara, Satoru*; Morisaki, Tomohiro*; Nakajima, Noriyoshi*; et al.
no journal, ,
no abstracts in English
