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(Copepoda) from a deep sediment-trap; Abundance and implications for ecological and biogeochemical studiesIkenoue, Takahito*; Otosaka, Shigeyoshi*; Honda, Makio*; Kitamura, Minoru*; Mino, Yoshihisa*; Narita, Hisashi*; Kobayashi, Takuya
Frontiers in Marine Science (Internet), 9, p.884320_1 - 884320_11, 2022/05
Times Cited Count：0 Percentile：0.01(Environmental Sciences)We studied seasonal variations of the mesozooplankton swimmer community collected by a sediment trap moored at 873 m in the Kuroshio & Oyashio Transition region off the east coast of Japan from 5 August 2011 to 23 June 2013. The total flux of mesozooplankton swimmers varied between 0 and 11.1 individuals m-2 d-1, with a mean of 3.1 individuals m-2 d-1 during the sampling period. Among the Copepoda, Neocalanus cristatus was the most dominant taxon. The species composition of the swimmers closely reflected the mid-depth mesozooplankton of the Oyashio region. The fluxes of Neocalanus species reflected ontogenetic vertical migration, but may have been overestimates of active fluxes if they included dormant individuals that accidentally entered the sediment trap.
Tsuda, Shuichi; Yoshida, Tadayoshi; Nakahara, Yukio; Sato, Tetsuro; Seki, Akiyuki; Matsuda, Norihiro; Ando, Masaki; Takemiya, Hiroshi; Tanigaki, Minoru*; Takamiya, Koichi*; et al.
JAEA-Technology 2013-037, 54 Pages, 2013/10
JAEA-Technology-2013-037.pdf:4.94MB
JAEA has been performing dose rate mapping in air using a car-borne survey system KURAMA-II. The KURAMA system is a GPS-aided mobile radiation monitoring system that has been newly developed by Kyoto University Research Reactor Institute in response to the nuclear disaster. The KURAMA system is composed of an energy-compensated scintillation survey meter for measuring dose rate, electric device for controlling both the dose rates and the position data from a GPS module, a computer server for processing and analyzing data from KURAMA, and client PCs for providing for end users. The KURAMA-II has been improved in small-packaging, durability, and automated data transmission. In consequence, dose rate mapping in wide area has become possible in shorter period of time. This report describes the construction of KURAMA-II, its application and a suggestion of how to manage a large number of KURAMA-II.
Shibano, Junichi*; Kiso, Minoru*; Kajiwara, Kentaro*; Shobu, Takahisa; Miura, Setsuo*; Kobayashi, Michiaki*
Zairyo, 62(7), p.443 - 450, 2013/07
The ductile damage progress of the FCC single crystal was verified by the profile analysis using the white X-ray obtained in BL28B2 beam-line of SPring-8. In this study, an aluminum single crystal of the purity 6N was used as a specimen prepared in the I-type geometry for tensile test. The notch was introduced into one side of the center of a parallel part of the specimen by wire electric discharge machining. White X-ray, which has 200 microns in height and 100 microns in width, was incident into the specimen on the Bragg angle of 3
in the horizontal plane using energy dispersive X-ray diffraction technique. As a result, in 1.1% of applied strain, increase of the lattice strain was observed in the direction of about 45 of slant from the notch bottom. In 2.2% of applied strain, the lattice strain reduced in the direction of about 45 of slant from the notch bottom. Non-uniform strain and dislocation density decreased similarly.
Kojima, Atsushi; Hanada, Masaya; Tanaka, Yutaka*; Kawai, Mikito*; Akino, Noboru; Kazawa, Minoru; Komata, Masao; Mogaki, Kazuhiko; Usui, Katsutomi; Sasaki, Shunichi; et al.
Nuclear Fusion, 51(8), p.083049_1 - 083049_8, 2011/08
Times Cited Count：51 Percentile：88.4(Physics, Fluids & Plasmas)Hydrogen negative ion beams of 490 keV, 3 A and 510 keV, 1 A have been successfully produced in the JT-60 negative ion source with three acceleration stages. These successful productions of the high-energy beams at high current have been achieved by overcoming the most critical issue, i.e., a poor voltage holding of the large negative ion sources with the grids of 2 m
for JT-60SA and ITER. To improve voltage holding capability, the breakdown voltages for the large grids was examined for the first time. It was found that a vacuum insulation distance for the large grids was 6-7 times longer than that for the small-area grid (0.02 m). From this result, the gap lengths between the grids were tuned in the JT-60 negative ion source. The modification of the ion source also realized a significant stabilization of voltage holding and a short conditioning time. These results suggest a practical use of the large negative ion sources in JT-60SA and ITER.
Kojima, Atsushi; Hanada, Masaya; Tanaka, Yutaka*; Kawai, Mikito*; Akino, Noboru; Kazawa, Minoru; Komata, Masao; Mogaki, Kazuhiko; Usui, Katsutomi; Sasaki, Shunichi; et al.
Proceedings of 23rd IAEA Fusion Energy Conference (FEC 2010) (CD-ROM), 8 Pages, 2011/03
Hydrogen negative ion beams of 490keV, 3A and 510 keV, 1A have been successfully produced in the JT-60 negative ion source with three acceleration stages. These successful productions of the high-energy beams at high current have been achieved by overcoming the most critical issue, i.e., a poor voltage holding of the large negative ion sources with the grids of 
2 m for JT-60SA and ITER. To improve voltage holding capability, the breakdown voltages for the large grids was examined for the first time. It was found that a vacuum insulation distance for the large grids was 6-7 times longer than that for the small-area grid (0.02 m). From this result, the gap lengths between the grids were tuned in the JT-60 negative ion source. The modification of the ion source also realized a significant stabilization of voltage holding and a short conditioning time. These results suggest a practical use of the large negative ion sources in JT-60 SA and ITER.
Kobayashi, Takayuki; Isayama, Akihiko; Fasel, D.*; Yokokura, Kenji; Shimono, Mitsugu; Hasegawa, Koichi; Sawahata, Masayuki; Suzuki, Sadaaki; Terakado, Masayuki; Hiranai, Shinichi; et al.
Journal of Plasma and Fusion Research SERIES, Vol.9, p.363 - 368, 2010/08
Improvements are required for expanding the pulse length of the JT-60 ECRF system (5s) for JT-60SA (100s). Newly developed power supplies will be fabricated and installed by EU. The conditioning operation of an improved gyrotron equipping a newly designed mode convertor has been started. The mode convertor will reduce heat flux on the internal components and therefore expected to enable long pulse operation at 1 MW. Pre-programmed and/or feedback control of the heater current and anode voltage, which was successfully demonstrated in JT-60U, will be key techniques because the beam current decreases during a shot. The evacuated transmission lines have a capability of 1 MW per line. Since maintenance of the components in the vacuum vessel is difficult, a linear motion antenna concept was proposed to reduce risks of water leakage and fault of the driving mechanism in the vacuum vessel. The detailed design and the low power test of a mock-up antenna have been started.
Ikeda, Yoshitaka; Hanada, Masaya; Kamada, Masaki; Kobayashi, Kaoru; Umeda, Naotaka; Akino, Noboru; Ebisawa, Noboru; Inoue, Takashi; Honda, Atsushi; Kawai, Mikito; et al.
IEEE Transactions on Plasma Science, 36(4), p.1519 - 1529, 2008/08
Times Cited Count：12 Percentile：41.25(Physics, Fluids & Plasmas)The JT-60SA N-NBI system is required to inject 10 MW for 100 s at 500 keV. Three key issues should be solved for the JT-60SA N-NBI ion source. One is to improve the voltage holding capability. Recent R&D tests suggested that the accelerator with a large area of grids may need a high margin in the design of electric field and a long time for conditioning. The second issue is to reduce the grid power loading. It was found that some beamlets were strongly deflected due to beamlet-beamlet interaction and strike on the grounded grid. The grids are to be designed by taking account of beamlet-beamlet interaction in three-dimensional simulation. Third is to maintain the D- production for 100 s. A simple cooling structure is proposed for the active cooled plasma grid, where a key is the temperature gradient on the plasma grid for uniform D- production. The modified N-NBI ion source will start on JT-60SA in 2015.
Koarashi, Jun; Mikami, Satoshi; Nakada, Akira; Akiyama, Kiyomitsu; Kobayashi, Hirohide; Fujita, Hiroki; Takeishi, Minoru
Journal of Nuclear Science and Technology, 45(Suppl.5), p.462 - 465, 2008/06
Times Cited Count：7 Percentile：44.56(Nuclear Science & Technology)Tokai reprocessing plant (TRP) has released radionuclides such as 
H, 
C, 
Kr and 
I into the atmosphere since the start of operation in 1977. We have established the monitoring methodologies for these nuclides, to realize an appropriate and continuous radioactive discharge control. The methodologies having various special technical considerations for matching the monitoring of reprocessing off-gas, were summarized in this paper. Briefly, H was collected by a cold-trap technique and the concentration was evaluated being independent of the water collection efficiency; C was collected by a monoethanolamine bubbler and then measured by liquid scintillation counting without any interferences from H and Kr; Kr was continuously measured by combination of two kinds of detectors to cover very wide range of the concentration; and I was collected by a charcoal filter and a charcoal cartridge in series with a relatively high collecting performance.
Nakai, Satoru; Aoyama, Takafumi; Ito, Chikara; Yamamoto, Masaya; Iijima, Minoru; Nagaoki, Yoshihiro; Kobayashi, Atsuko; Onoda, Yuichi; Ohgama, Kazuya; Uwaba, Tomoyuki; et al.
Kosoku Jikkenro "Joyo" Rinkai 30-Shunen Kinen Hokokukai Oyobi Gijutsu Koenkai, 154 Pages, 2008/06
no abstracts in English
Koarashi, Jun; Takeishi, Minoru; Kobayashi, Hirohide
Proceedings of International Symposium on Environmental Modeling and Radioecology, p.223 - 230, 2007/03
no abstracts in English
CuO
Uematsu, Daisuke*; Soda, Minoru*; Kobayashi, Yoshiaki*; Sato, Masatoshi*; Igawa, Naoki; Kakurai, Kazuhisa
Journal of the Physical Society of Japan, 75(12), p.124601_1 - 124601_5, 2006/12
Times Cited Count：0 Percentile：0(Physics, Multidisciplinary)The close coupling of the crystal distortion to the magnetic ordering in AgCuO at 70K has been found by X-ray and neutron diffraction analyses and magnetic measurements. The system has a pyrochlore-related structure with corner-sharing tetrahedra of Cu
ions, in which the geometrical frustration is inherent. We report how the structural distortion releases the frustration, stabilizing the magnetic ordered state.
CoO
DO; Neutron scatteringMoyoshi, Taketo*; Yasui, Yukio*; Soda, Minoru*; Kobayashi, Yoshiaki*; Sato, Masatoshi*; Kakurai, Kazuhisa
Journal of the Physical Society of Japan, 75(7), p.074705_1 - 074705_6, 2006/07
Times Cited Count：11 Percentile：56.33(Physics, Multidisciplinary)Neutron scattering investigations on single crystal NaCoO y(DO) have been carried out. Strong 2-D diffuse scattering due to the short-range ordered state of DO molecules are observed. Significant scattering has been also observed for phonons originating from the vibrations of the short-range ordered DO molecules. No firm evidence for the magnetic fluctuations has been found for the hydrated superconducting component NaCoO y(DO), while the very weak intensity modulation observed in the scans along (1/2,1/2,l) suggests the existence of the antiferromagnetic fluctuations in the non-hydrated parts of the sample.
H and C in radioactive airborne effluentKoarashi, Jun; Mikami, Satoshi; Akiyama, Kiyomitsu; Kobayashi, Hirohide; Takeishi, Minoru
Journal of Radioanalytical and Nuclear Chemistry, 268(3), p.475 - 479, 2006/06
A simple and reliable sampling system for H and C in airborne release from nuclear facilities was designed. The sampling system can collect H and C simultaneously with a condensation technique using a commercially available cold trap equipment and a CO absorption technique using an organic alkali solution monoethanolamine, respectively. In situ performance tests for the effluent from a reprocessing plant showed that the system has the high and stable efficiencies for collecting H and C for a one-week batch sampling at a sampling flow rate of 0.4 l min
. These collection techniques also provided a simple procedure of following sample preparations for activity measurement by liquid scintillation counting. The detectable concentrations of the proposed monitoring method were 3.0Bq/m for H and 1.6Bq/m for C, respectively. The sensitivity would be acceptable level for routine monitoring of airborne release at nuclear facilities.
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.
Nd
Sr
CuO
Ito, Masafumi*; Yasui, Yukio*; Iikubo, Satoshi*; Soda, Minoru*; Sato, Masatoshi*; Kobayashi, Akito*; Kakurai, Kazuhisa
Journal of the Physical Society of Japan, 72(7), p.1627 - 1630, 2003/07
Times Cited Count：9 Percentile：52.56(Physics, Multidisciplinary)no abstracts in English
Kobayashi, Hirohide; ; ; ; Ebana, Minoru*
JNC TN8410 2002-011, 24 Pages, 2002/10
JNC-TN8410-2002-011.pdf:4.36MB
At present, alpha contamination measurement on objects is conducted with ZnS scintillation survey meter (direct method) and smear test (indirect method). But it is difficult to measure large and complicated objects by direct method. Long Range Alpha Detector (LRAD) was produced as a solution for this problem. We carried out performance tests of this LRAD. As a result of the performance tests, we confirmed the linear relation between the measurement values of LRAD and alpha-radioactivity on the surface of objects.
Kobayashi, Minoru*
JAERI-Data/Code 2002-016, 40 Pages, 2002/09
JAERI-Data-Code-2002-016.pdf:3.78MB
no abstracts in English
Shinohara, Kunihiko; ; Maruo, Yoshihiro; Momose, Takumaro; Takeishi, Minoru; Kobayashi, Hirohide;
JNC TN8440 2002-009, 99 Pages, 2002/08
This annual report is summary of the activities of Radiation Protection Division at JNC Tokai Works in fiscal year of 2001. This report consists of the introduction of the radiation control in working area of the reprocessing plant, the MOX fuel fabrication facilities and laboratories, the discharges control of these facilities, the personal dosimetry, the environmental monitoring, the control of radiation standards and calibration, the maintenance of radiation measurement instruments, the safety study, the technical support for outside organizations and other activities.
Umemoto, Michitaka; Kobayashi, Kensuke; Ishigami, Tsutomu; Watanabe, Minoru*
Chiiki Anzen Gakkai Kogaishu, 10, p.113 - 116, 2000/11
On September 30 in 1999, the reactivity accident occurred at the Tokai uranium processifn facility of J. C. O. Co. Ltd(JCO) at Tokai-mura, Japan. Before the accident had been brought under control, the local authorities evacuated the population living within a few hundred meters and advised people within 10km of the facility to take shelter for a period of about one day. Questionnaires were conducted to know when, where and how the inhabitants received the information of protective action requests from the local authories and how they responded to the requests.
Kobayashi, Minoru*
JAERI-Data/Code 2000-022, p.85 - 0, 2000/03
JAERI-Data-Code-2000-022.pdf:2.83MB
no abstracts in English
