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Nakano, Tomohide; Asakura, Nobuyuki; Takenaga, Hidenobu; Kubo, Hirotaka; Miura, Yukitoshi; Shimizu, Katsuhiro; Konoshima, Shigeru; Masaki, Kei; Higashijima, Satoru; JT-60 Team
Nuclear Fusion, 46(5), p.626 - 634, 2006/05
Times Cited Count：21 Percentile：56.18(Physics, Fluids & Plasmas)In order to understand plasma-wall interactions in a long time scale, the discharge pulse length has been extended from 15 s to 65 s, with the NB-heating duration extended to 30 s. Nearly-saturation of the divertor plates was observed in the latter half of long pulse ELMy H-mode discharges. Particle sink into the divertor plates gradually decreased, and subsequently, wall-pumping efficiency became zero. This wall saturation resulted in a rise of the main plasma density without any auxiliary particle supply besides NB with divertor-pumping. Even when the total injected energy reached up to 
350 MJ in a discharge, neither sudden increase of carbon generation such as carbon bloom nor increase of the dilution of the main plasma was observed.
Fujiwara, Yukio; Watanabe, Kazuhiro; Okumura, Yoshikazu; Trainham, R.*; Jacquot, C.*
Review of Scientific Instruments, 76(1), p.013501_1 - 013501_5, 2005/01
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)A new actively-cooled plasma electrode has been developed for long pulse operation in a cesium-seeded negative ion source. To keep the electrode temperature at about 300 
C, which is optimum range of temperature to enhance cesium effects, the electrode cooling structure has been designed using three-dimensional numerical simulation assuming that the heat flux from the source plasma was 15 W/cm
. Water cooling tubes were brazed to the plasma electrode substrate with spacers made of stainless steel which acts as a thermal resistance. The fabricated plasma electrode has been tested in a cesium-seeded volume negative ion source called Kamaboko source. The temperature of the electrode reached 280 C for the arc power of 41 kW, which is operating condition required for producing D- beams with current densities exceeding 20 mA/cm. It was demonstrated that the actively-cooled plasma electrode is applicable to long pulse operations, meeting the temperature requirement for optimizing the surface-production process of negative ions in the cesium seeded ion source.
Kusagaya, Kazuyuki*; Sugiyama, Tomoyuki; Nakamura, Takehiko; Uetsuka, Hiroshi
JAERI-Tech 2002-105, 24 Pages, 2003/01
High-temperature and high-pressure influence on the destructive force at the fuel rod failure in reactivity-initiated-accident (RIA) simulating experiment using the NSRR (Nuclear Safety Research Reactor) is estimated, for the purpose of mechanical designing of a new experimental capsule for simulating the temperature and pressure condition of typical commercial BWR. When knowledge on pressure impulse and water hammer, which are the cause of the destructive force, and steam property dependence on temperature and pressure are taken into account, one can qualitatively estimate that the destructive force in the BWR operation condition is smaller than that in the room temperature and atmospheric pressure condition. The water column velocity, which determines the impact by water hammer, is further investigated quantitatively by modeling the experimental system and the water hammer phenomenon. As a result, the maximum velocity of water column in the BWR operation condition is calculated to be only about 10% of that in the room temperature and atmospheric pressure condition.
Ando, Toshinari*; Isono, Takaaki; Kato, Takashi; Koizumi, Norikiyo; Okuno, Kiyoshi; Matsui, Kunihiro; Martovetsky, N.*; Nunoya, Yoshihiko; Ricci, M.*; Takahashi, Yoshikazu; et al.
IEEE Transactions on Applied Superconductivity, 12(1), p.496 - 499, 2002/03
Times Cited Count：5 Percentile：34.74(Engineering, Electrical & Electronic)no abstracts in English
Nakamura, Takehiko; Katanishi, Shoji; Kashima, Yoichi; Yachi, Shigeyasu; Yoshinaga, Makio; Terakado, Yoshibumi
Journal of Nuclear Science and Technology, 39(3), p.264 - 272, 2002/03
Times Cited Count：9 Percentile：50.57(Nuclear Science & Technology)In order to study fuel behavior under abnormal transients and accidents, the control system of the Nuclear Safety Research Reactor (NSRR) of the Japan Atomic Energy Research Institute (JAERI) was modified to achieve high power transients. With this new operational mode, called Shaped Pulse (SP), transients at the maximum power of 10 MW can be conducted for a few seconds. This new operational mode supplements the previous Natural Pulse (NP) operation at the maximum power of 23 GW for milliseconds. For high power transient operation, a simulator using a point kinetic model was developed, and characteristics of the NSRR in the new operational mode were examined through tests and calculations. With the new operational mode, new types of fuel irradiation tests simulating power oscillations of boiling water reactors (BWRs) can to be conducted in the NSRR. Reactor characteristics and capability, such as control rod worth, feedback reactivity, and operational limits of the NSRR for SP operations are discussed.
Ando, Toshinari; Hiyama, Tadao; Takahashi, Yoshikazu; Nakajima, Hideo; Kato, Takashi; Isono, Takaaki; Sugimoto, Makoto; Kawano, Katsumi; Koizumi, Norikiyo; Nunoya, Yoshihiko; et al.
IEEE Transactions on Applied Superconductivity, 10(1), p.568 - 571, 2000/03
Times Cited Count：10 Percentile：53.16(Engineering, Electrical & Electronic)no abstracts in English
Nagao, Yoshiharu; Nakamichi, Masaru; Kawamura, Hiroshi
Journal of Nuclear Science and Technology, 37(Suppl.1), p.423 - 426, 2000/03
no abstracts in English
Sugimoto, Makoto; Kato, Takashi; Isono, Takaaki; Yoshida, Kiyoshi; Tsuji, Hiroshi
Cryogenics, 39(4), p.323 - 330, 1999/00
Times Cited Count：4 Percentile：23.55(Thermodynamics)no abstracts in English
Sugimoto, Makoto; Isono, Takaaki; Tsuji, Hiroshi; Yoshida, Kiyoshi; ; Hamajima, Takataro*; Sato, Takashi*; Shinoda, K.*
Cryogenics, 38(10), p.989 - 994, 1998/00
Times Cited Count：4 Percentile：23.76(Thermodynamics)no abstracts in English
Minehara, Eisuke; Sugimoto, Masayoshi; Sawamura, Masaru; Nagai, Ryoji; Kikuzawa, Nobuhiro; Nishimori, Nobuyuki;
Proc. of 11th Symp. on Accelerator Sci. and Technol., P. 120, 1997/00
no abstracts in English
Sn demo poloidal coil(DPC-EX)Ando, Toshinari; Nakajima, Hideo; ; Hiyama, Tadao; Takahashi, Yoshikazu; Nishi, Masataka; Yoshida, Kiyoshi; Okuno, Kiyoshi; Kato, Takashi; Sugimoto, Makoto; et al.
Advances in Cryogenic Engineering, Vol.39, 0, p.335 - 341, 1994/00
no abstracts in English
Ando, Toshinari
Proc. of the 7th US-Japan Workshop on High-Field Superconducting Materials, Wires and Conductors, p.23 - 27, 1991/00
no abstracts in English
