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Sn strand subjected to bending strainHirohashi, Masayuki*; Murakami, Haruyuki*; Ishiyama, Atsushi*; Ueda, Hiroshi*; Koizumi, Norikiyo; Okuno, Kiyoshi
IEEE Transactions on Applied Superconductivity, 16(2), p.1721 - 1724, 2006/06
Times Cited Count：9 Percentile：46.34(Engineering, Electrical & Electronic)To demonstrate the applicability of NbSn CICCs to ITER, four NbSn model coils have been constructed and tested. The experimental results showed that the measured critical current (Ic) degraded. In addition, the larger is the applied electromagnetic force, the larger the magnitude of the degradation is. The degradation in n-value was also observed. One of the explanations of this degradation is a local strand bending. This consideration has been supported by the test results. However, general dependence of Ic on periodic bending strain has not been clarified in this test since the experiments were carried out at a certain magnetic field, temperature and strain. Therefore, a numerical simulation code was developed to study the general dependence of the Ic and n-value of the NbSn strand on periodic bending strain. A distributed constant circuit model is applied to simulate current transfer among the filaments in the strand. The simulation results show relatively good agreement with the experiment results but some modification in modeling is required for more accurate simulation.
Hamada, Kazuya; Nakajima, Hideo; Kawano, Katsumi; Takano, Katsutoshi*; Tsutsumi, Fumiaki*; Seki, Shuichi*; Okuno, Kiyoshi; Fujitsuna, Nobuyuki*; Mizoguchi, Mitsuru*
IEEE Transactions on Applied Superconductivity, 16(2), p.787 - 790, 2006/06
Times Cited Count：6 Percentile：37.07(Engineering, Electrical & Electronic)no abstracts in English
Koizumi, Norikiyo; Nunoya, Yoshihiko; Okuno, Kiyoshi
IEEE Transactions on Applied Superconductivity, 16(2), p.831 - 834, 2006/06
Times Cited Count：24 Percentile：70.33(Engineering, Electrical & Electronic)no abstracts in English
Nishimura, Arata*; Muroga, Takeo*; Takeuchi, Takao*; Nishitani, Takeo; Morioka, Atsuhiko
Fusion Engineering and Design, 81(8-14), p.1675 - 1681, 2006/02
Times Cited Count：3 Percentile：23.92(Nuclear Science & Technology)In a fusion reactor plant, a neutral beam injector (NBI) will be operated for a long time, and it will allow neutron streaming from NBI ports to outside of the plasma vacuum vessel. It requires the superconducting magnet to develop nuclear technology to produce stable magnetic field and to reduce activation of the magnet components. In this report, the back ground of the necessity and the contents of the nuclear technology of the superconducting magnets for fusion application are discussed and some typical investigation results are presented, which are the neutron irradiation effect on NbSn wire, the development of low activation superconducting wire, and the design concept to reduce nuclear heating and nuclear transformation by streaming. In addition, recent activities in high energy particle physics are introduced and potential ripple effect of the technology of the superconducting magnets is described briefly.
Kizu, Kaname; Miura, Yushi*; Tsuchiya, Katsuhiko; Ando, Toshinari*; Koizumi, Norikiyo; Matsui, Kunihiro*; Sakasai, Akira; Tamai, Hiroshi; Matsukawa, Makoto; Ishida, Shinichi; et al.
Nuclear Fusion, 45(11), p.1302 - 1308, 2005/11
Times Cited Count：4 Percentile：14.06(Physics, Fluids & Plasmas)no abstracts in English
Yoshida, Kiyoshi; Takahashi, Yoshikazu; Mitchell, N.*; Bessette, D.*; Kubo, Hiroatsu*; Sugimoto, Makoto; Nunoya, Yoshihiko; Okuno, Kiyoshi
IEEE Transactions on Applied Superconductivity, 14(2), p.1405 - 1409, 2004/06
Times Cited Count：16 Percentile：59.71(Engineering, Electrical & Electronic)The ITER Central Solenoid (CS) is 12m high and 4m in diameter. The CS consists of a stack of 6electrically independent modules to allow control of plasma shape. The modules are compressed vertically by a pre-compression structure to maintain contact between modules. The CS conductor is CIC conductor with NbSn strands and a steel conduit. The CS model coil and insert coil test results have shown that the conductor design must be modified to achieve an operation margin. This required either to increase the cable diameter or to use strand with a higher current capability. A bronze-process (NbTi)Sn strand is proposed to achieve a higher critical magnetic field. A square conduit with a high Mn stainless steel is proposed as it can satisfy fatigue requirements. The inlets are in the high stress region and any stress intensification there must be minimized. The pre-compression structure is composed of 9tie plates to reduce the stress on the cooling pipes. These design proposals satisfy all ITER operational requirements.
Nunoya, Yoshihiko; Isono, Takaaki; Okuno, Kiyoshi
IEEE Transactions on Applied Superconductivity, 14(2), p.1468 - 1472, 2004/06
Times Cited Count：45 Percentile：83.18(Engineering, Electrical & Electronic)The voltage temperature characteristic curve (V-T curve) observed in the large-current NbSn CIC conductor, which was used in the ITER CS Insert, showed a gradual take-off toward normal state as compared with the V-T curve of an individual strand composing the conductor. The gradual take-off corresponds to the reduction in so-called "n-value." In addition, the take-off shifted to lower temperature than that of the strand, namely lower current sharing temperature (Tcs) or lower critical current (Ic). These behaviors cannot be explained by non-uniform magnetic field accompanying enlargement of the conductor, or by non-uniform contact resistance of the conductor terminals. Investigation is therefore required to clarify the condition of each strand in such large CIC conductor, especially in terms of the strain state under large electromagnetic force. In a CIC conductor, since strands are twisted to form a cable, each strand is mechanically supported by a nearby strand at an interval related to the twist pitch. Between two supporting points, the strand is fee to move under transverse force and a cyclic deformation will occur along the strand length. We designed the apparatus to simulate this cyclic deformation and measured the V-T characteristic of the strand. When the strand received the transverse force of about 500 N/m, n-value reduced to one-fifth (about 6) of the original value, which corresponds to that observed in the CS Insert. The level of the force agreed to the electromagnetic force when the CS Insert was energized to 46 kA at 13 T (about 40 A each strand 
13 T = 520 N/m). This suggests that the transverse force acting on each strand can explain the behavior of the V-T curve of the large-current CIC conductor.
Takahashi, Yoshikazu; Yoshida, Kiyoshi; Mitchell, N.*; Bessette, D.*; Nunoya, Yoshihiko; Matsui, Kunihiro; Koizumi, Norikiyo; Isono, Takaaki; Okuno, Kiyoshi
IEEE Transactions on Applied Superconductivity, 14(2), p.1410 - 1413, 2004/06
Times Cited Count：10 Percentile：47.92(Engineering, Electrical & Electronic)Cable-in-conduit conductors that consist of about 1,000 NbSn strands with an outer diameter of about 0.8mm, have been designed for the TF and CS coils of the ITER. The rated current of these coils is 40 -68kA. Two joint types (Butt and Lap) were developed during the CS Model Coil project. The performance of these joints was evaluated during the operating tests and the satisfied results were obtained. The joints of the TF coils are located outside of the winding in a region where the magnetic field is about 2.1T, a very low value as compared to the maximum field of 11.8T at the winding. The CS joints are located at the coil outer diameter and embedded within the winding pack due to the lack of the space. The maximum fields at the CS joint and winding are 3.5 and 13T, respectively. For the TF coils and the CS, the joints are cooled in series with the conductor at the outlet. The maximum temperature increase due to the joule heating in the joints is set at 0.15K to limit the heat load on the refrigerator. It is shown that both joint types are applicable to the ITER coils.
Al insert; Characteristics of acoustic emissionNinomiya, Akira*; Arai, Kazuaki*; Takano, Katsutoshi*; Tsugawa, Kazuhito*; Ishigooka, Takeshi*; Kaiho, Katsuyuki*; Nakajima, Hideo; Okuno, Kiyoshi; CS Model Coil Test Group
Teion Kogaku, 38(8), p.425 - 433, 2003/08
The charge test of Central Solenoid Model Coil(CSMC) and Toroidal Field Insert Coil(TFIC) were carried out fo about one month from September 2001 with international collaboration under ITER EDA. In the experiment, Acoustic Emission(AE) signals were measured which were induced from CSMC and TFIC. It was the first trial to measure the AE signals from the insert coil directly. Relations among AE signals from TFIC, intensity, number and voltages are discussed in this paper.
Sugimoto, Makoto; Nakajima, Hideo; Kato, Takashi; Okuno, Kiyoshi; Tsuji, Hiroshi; Rodin, I.*; Egorov, S. A.*
Teion Kogaku, 37(10), p.513 - 522, 2002/10
The Central Solenoid (CS) model coil programme has been carrying out since 1992 as a back born project in International Thermonuclear Experimental Reactor (ITER) Engineering Design Activity (EDA). The CS model coil programme has a plan to develop the toroidal fieled (TF) insert to demonstrate the conductor performance of ITER real TF coils under 13 T of magnetic flux density. The fabrication of TF insert was completed on May 2001 by D.V.Efremov Scientific Research Institute for Electrophysical Apparatus(Efremov institute) at St. Petersburg, Russia. Experiments including the cooldown and warmup were completed November 2001 at JAERI Naka. TF insert was achieved to charge up to 13T with 46kA without training under the back up magnetic field by the CS model coil.
Sn and NbTi CIC conductors for supercoducting poloidal field coils of JT-60Miura, Yushi; Kizu, Kaname; Tsuchiya, Katsuhiko; Isono, Takaaki; Matsui, Kunihiro; Sakasai, Akira; Ishida, Shinichi; Matsukawa, Makoto; Ando, Toshinari
IEEE Transactions on Applied Superconductivity, 12(1), p.611 - 614, 2002/03
Times Cited Count：8 Percentile：45.10(Engineering, Electrical & Electronic)no abstracts in English
Al and NbSn CICCs for superconducting toroidal field coils of JT-60Kizu, Kaname; Miura, Yushi; Tsuchiya, Katsuhiko; Matsui, Kunihiro; Isono, Takaaki; Sakasai, Akira; Matsukawa, Makoto; Ishida, Shinichi; Ando, Toshinari
IEEE Transactions on Applied Superconductivity, 12(1), p.575 - 578, 2002/03
Times Cited Count：9 Percentile：47.62(Engineering, Electrical & Electronic)no abstracts in English
Shimamoto, Susumu*; Murase, Satoru*; Nishii, Kenji*; Naito, Fuminobu*; Matsui, Kunihiro; Takahashi, Yoshikazu; Tsuji, Hiroshi
Denki Gakkai Rombunshi, B, 122(1), p.58 - 63, 2002/01
no abstracts in English
Tsuji, Hiroshi; Okuno, Kiyoshi*; Thome, R.*; Salpietro, E.*; Egorov, S. A.*; Martovetsky, N.*; Ricci, M.*; Zanino, R.*; Zahn, G.*; Martinez, A.*; et al.
Nuclear Fusion, 41(5), p.645 - 651, 2001/05
Times Cited Count：58 Percentile：83.02(Physics, Fluids & Plasmas)no abstracts in English
Galindo, V.*; Ciarynski, D.*; Duchateau, J. L.*; Nishijima, Gen; Koizumi, Norikiyo; Takahashi, Yoshikazu; Ando, Toshinari
IEEE Transactions on Applied Superconductivity, 11(1), p.1538 - 1541, 2001/03
Times Cited Count：12 Percentile：57.65(Engineering, Electrical & Electronic)no abstracts in English
Naka Fusion Research Establishment
JAERI-Review 2000-030, 113 Pages, 2001/01
JAERI-Review-2000-030.pdf:10.11MB
no abstracts in English
Ushigusa, Kenkichi; Isayama, Akihiko; Kurita, Genichi; Ishida, Shinichi; Neyatani, Yuzuru; Ishiyama, Shintaro; Kikuchi, Mitsuru; Otsuka, M.*; Sasaki, T.*; Nakagawa, S.*; et al.
Fusion Engineering and Design, 51-52, p.371 - 376, 2000/11
Times Cited Count：2 Percentile：19.30(Nuclear Science & Technology)no abstracts in English
Ando, Toshinari; Hiyama, Tadao; Takahashi, Yoshikazu; Nakajima, Hideo; Kato, Takashi; Isono, Takaaki; Sugimoto, Makoto; Kawano, Katsumi; Koizumi, Norikiyo; Nunoya, Yoshihiko; et al.
Denki Gakkai Rombunshi, B, 120(3), p.449 - 456, 2000/03
no abstracts in English
Sugimoto, Makoto; Isono, Takaaki; Nunoya, Yoshihiko; Koizumi, Norikiyo; Nakajima, Hideo; Kato, Takashi; Matsukawa, Makoto; Hamada, Kazuya; Matsui, Kunihiro; Nishijima, Gen; et al.
IEEE Transactions on Applied Superconductivity, 10(1), p.564 - 567, 2000/03
Times Cited Count：22 Percentile：70.80(Engineering, Electrical & Electronic)no abstracts in English
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：53.31(Engineering, Electrical & Electronic)no abstracts in English
