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Kawamura, Hideyuki; Hirose, Naoki*; Nakayama, Tomoharu*; Ito, Toshimichi
JAEA-Data/Code 2021-004, 34 Pages, 2021/05
JAEA-Data-Code-2021-004.pdf:3.72MB
The Japan Atomic Energy Agency measured the ocean current across the Tsugaru Strait using an Acoustic Doppler Current Profiler attached on a ferryboat from October 1999 to January 2008. The characteristics of the ocean current in the Tsugaru Strait must be understood for predicting oceanic dispersion of radioactive materials released from nuclear facilities around the strait. Furthermore, it is critical to elucidate the mechanism of the Tsugaru Warm Current from an oceanography viewpoint. The dataset obtained in this investigation consists of daily ocean current data files that record the components of the current speed in the east-west and north-south directions from the surface layer to the bottom layer. The dataset stores 2,211 daily ocean current data files, despite some data periods missing from October 1999 to January 2008. In this study, information on the dataset is described for users to analyze the dataset properly for their purposes. Section 1 provides the background and purpose of the ocean current measurement, Section 2 explains the methodology of measurement using an Acoustic Doppler Current Profiler, and Section 3 explains the record format of the daily ocean current data files and data acquisition rate and presents analysis results. Finally, Section 4 concludes this study.
Meigo, Shinichiro; Noda, Fumiaki*; Ishikura, Shuichi*; Futakawa, Masatoshi; Sakamoto, Shinichi; Ikeda, Yujiro
Nuclear Instruments and Methods in Physics Research A, 562(2), p.569 - 572, 2006/06
Times Cited Count：20 Percentile：78.69(Instruments & Instrumentation)no abstracts in English
Oikawa, Toshihiro; Suzuki, Takahiro; Isayama, Akihiko; Hayashi, Nobuhiko; Fujita, Takaaki; Naito, Osamu; Tsuda, Takashi; Kurita, Genichi; JT-60 Team
Nuclear Fusion, 45(9), p.1101 - 1108, 2005/09
Times Cited Count：4 Percentile：14.20(Physics, Fluids & Plasmas)Evolution of the current density profile associated with magnetic island formation in a neoclassical tearing mode plasma was measured for the first time in JT-60U by. As the island grew, the current density profile turned flat at the radial region of the island, followed by an appearance of a hollow structure. As the island shrank, the deformed region became narrower, and it finally diminished after the disappearance of the island. In an MHD-quiescent plasma, on the other hand, no deformation was observed. The observed deformation in the current density profile associated with the tearing mode is reproduced in a time dependent transport simulation assuming reduction of the bootstrap current in the radial region of the island. Comparison of the measurement with a calculated steady-state solution also explains the temporal behaviors of the current density and safety factor profiles with reduction and recovery of the bootstrap current. From the experimental observation and simulations, we reach conclusion that the bootstrap current decreases within the island O-point.
Oikawa, Toshihiro; Isayama, Akihiko; Fujita, Takaaki; Suzuki, Takahiro; Tsuda, Takashi; Kurita, Genichi
Physical Review Letters, 94(12), p.125003_1 - 125003_4, 2005/04
Times Cited Count：10 Percentile：53.37(Physics, Multidisciplinary)Evolution of the current density profile associated with the magnetic island formation during a tearing mode was measured for the first time in the JT-60U tokamak. With the island growth, the current density profile turned flat at the radial region of the island, followed by appearance of a hollow structure. As the island shrank, the flat region became narrower, and it finally diminished after disappearance of the island. It was also observed that the local poloidal magnetic field fluctuated in correlation with the island rotation. This indicates that the observed deformation in the current density profile is localized in the O-point of the island. The result is the first experimental demonstration of theoretical predictions on the current density evolution in tearing modes.
Tamai, Hiroshi; Kurita, Genichi; Matsukawa, Makoto; Urata, Kazuhiro*; Sakurai, Shinji; Tsuchiya, Katsuhiko; Morioka, Atsuhiko; Miura, Yushi; Kizu, Kaname; Kamada, Yutaka; et al.
Plasma Science and Technology, 6(3), p.2281 - 2285, 2004/06
Times Cited Count：0 Percentile：0.02(Physics, Fluids & Plasmas)High performance steady-state operation for JT-60SC are evaluated by the TOPICS analysis. 
5 and bootstrap current fraction 86% is kept steady at I
=1.5 MA, B
=2 T by neutral beam power of 11 MW. The ERATO-J analysis shows that the external-kink mode with multiple toroidal mode numbers of n=1 and n=2 is stable at 
5.5 at the average ratio of conducting wall radius to plasma minor radius of about 1.2 with the wall stabilisation effect. Resistive wall modes, induced by a close location of the wall to plasma, is expected to be suppressed by the active feedback stabilisation with a set of non-axisymmetric field coils behind the stabilising plates. Further optimisation for the high- accessibility by the plasma shaping is performed with the TOSCA analysis. The plasma shaping factor defined as S=(I/aB)q
and strongly correlated to the plasma elongation and triangularity, is scanned from 4 to 6, which extends the availability of current and pressure profile control for the high performance plasma operation.
Ozeki, Takahisa; Hamamatsu, Kiyotaka; Isayama, Akihiko; Kurita, Genichi
Fusion Engineering and Design, 53(1-4), p.65 - 69, 2001/01
Times Cited Count：7 Percentile：48.62(Nuclear Science & Technology)no abstracts in English
Kaminaga, Masanori; Yamamoto, Kazuyoshi; Sudo, Yukio
Journal of Nuclear Science and Technology, 35(12), p.943 - 951, 1998/12
Times Cited Count：24 Percentile：85.09(Nuclear Science & Technology)no abstracts in English
Kaminaga, Masanori; Yamamoto, Kazuyoshi; Sudo, Yukio
Proceedings of 8th International Topical Meeting on Nuclear Reactor Thermal-Hydraulics (NURETH-8), Vo.3, p.1815 - 1822, 1997/00
In research reactors, plate-type fuel elements are generally adopted so as to produce high power densities and are cooled by a downward flow. A core flow reversal from a steady-state forced downward flow to an upward flow due to natural convection should occur during operational transients such as "Loss of the primary coolant flow". Therefore, in the thermal hydraulic design of research reactors, critical heat flux (CHF) under a counter-current flow limitation (CCFL) or a flooding condition are important to determine safety margins of fuel against CHF during a core flow reversal. The authors have proposed a CHF correlation scheme for the thermal hydraulic design of research reactors, based on CHF experiments for both upward and downward flows including CCFL condition. When the CHF correlation scheme was proposed, a subcooling effect for CHF correlation under CCFL condition had not been considered because of a conservative evaluation and a lack of enough CHF data to determine the subcooling effect on CHF. A too conservative evaluation is not appropriate for the design of research reactors because of construction costs etc. Also, conservativeness of the design must be determined precisely. In this study, therefore, the subcooling effect on CHF under the CCFL conditions in vertical rectangular channels heated from both sides were investigated quantitatively based on CHF experimental results obtained under uniform and nonuniform heat flux condition. As a result, it was made clear that CHF in this region increase linearly with an increase of the channel inlet subcooling and a new CHF correlation including the effect of channel inlet subcooling was proposed.
Neyatani, Yuzuru; JT-60 Team
Plasma Physics and Controlled Fusion, 38(12A), p.181 - 191, 1996/00
Times Cited Count：14 Percentile：46.04(Physics, Fluids & Plasmas)no abstracts in English
Kondoh, Takashi; Ikeda, Yoshitaka; Ushigusa, Kenkichi; Seki, Masami; Ide, Shunsuke; Naito, Osamu;
Nihon Genshiryoku Gakkai-Shi, 37(2), p.124 - 132, 1995/00
Times Cited Count：1 Percentile：17.51(Nuclear Science & Technology)no abstracts in English
Ishida, Shinichi; Matsuoka, Mamoru; Kikuchi, Mitsuru; Tsuji, Shunji; Nishitani, Takeo; Koide, Yoshihiko; Ozeki, Takahisa; Fujita, Takaaki; Nakamura, Hiroo; Hosogane, Nobuyuki; et al.
Plasma Physics and Controlled Nuclear Fusion Research 1992, Vol.1, p.219 - 233, 1993/00
no abstracts in English
Tanaka, Shigeru; Ohara, Yoshihiro; Yamamoto, Shin
Fusion Technology, 91(3), p.531 - 539, 1991/05
no abstracts in English
Ozeki, Takahisa; Azumi, Masafumi; Ishida, Shinichi; Koide, Yoshihiko; Tokuda, Shinji
JAERI-M 90-180, 16 Pages, 1990/10
no abstracts in English
Yoshino, Ryuji; Ushigusa, Kenkichi; Imai, Tsuyoshi; Shirai, Hiroshi; Shimizu, Katsuhiro
JAERI-M 89-116, 12 Pages, 1989/09
no abstracts in English
Yoshino, Ryuji
JAERI-M 89-115, 11 Pages, 1989/09
no abstracts in English
; Yamamoto, Shin; Sugihara, Masayoshi; Fujisawa, Noboru
JAERI-M 87-209, 45 Pages, 1988/01
no abstracts in English
; ; ; ;
Nuclear Fusion, 27(4), p.549 - 567, 1987/04
Times Cited Count：2 Percentile：10.19(Physics, Fluids & Plasmas)no abstracts in English
