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Journal Articles

Analysis of maximum voltage transient of JT-60SA toroidal field coils in case of fast discharge

Novello, L.*; Cara, P.*; Coletti, A.*; Gaio, E.*; Maistrello, A.*; Matsukawa, Makoto; Philipps, G.*; Tomarchio, V.*; Yamauchi, Kunihito

IEEE Transactions on Applied Superconductivity, 26(2), p.4700507_1 - 4700507_7, 2016/03

 Times Cited Count:6 Percentile:35.42(Engineering, Electrical & Electronic)

Journal Articles

Fabrication of 8Cr-2W ferritic steel tile for reduction in toroidal magnetic field ripple on JT-60U

Kudo, Yusuke; Sawai, Tomotsugu; Sakurai, Shinji; Masaki, Kei; Suzuki, Yutaka; Sasajima, Tadayuki; Hayashi, Takao; Takahashi, Ryukichi*; Honda, Masao; Jitsukawa, Shiro; et al.

Journal of the Korean Physical Society, 49(96), p.S297 - S301, 2006/12

Installation of ferritic steel tiles was proposed in JT-60U to reduce the toroidal magnetic field ripple and to improve the fast ion loss, which degrades heating efficiency and increases heat load on plasma facing component under large volume plasma operations. We selected a 8Cr-2W-0.2V ferritic steel with the cost-effectiveness, in which concentration limits of activation elements in F82H were relaxed because of the less number of neutron generations from deuterium operations on JT-60U. The fabricated ferritic steel has clear tempered martensitic microstructure, and sufficient magnetic and mechanical properties. The saturated magnetization was estimated to 1.7 Tesla at 573 K, lower than expected, but effectiveness in JT-60U was confirmed by numerical analyses. To research the effect of material conditions, such as microstructure and heat treatment, on saturated magnetization of the ferritic steel based on 8-9Cr is important for the future fusion reactors which will be planned to install the ferritic steel as the in-vessel components.

Journal Articles

The Roles of plasma rotation and toroidal field ripple on the H-mode pedestal structure in JT-60U

Urano, Hajime; Kamiya, Kensaku; Koide, Yoshihiko; Takizuka, Tomonori; Oyama, Naoyuki; Kamada, Yutaka; JT-60 Team

Plasma Physics and Controlled Fusion, 48(5A), p.A193 - A199, 2006/05

 Times Cited Count:10 Percentile:35.74(Physics, Fluids & Plasmas)

The characteristics of the H-mode pedestal structure were investigated by conducting the power scans for a variation of the toroidal momentum sources at different toroidal field ripple in JT-60U. It was found that the pedestal pressure is increased by reduced loss power of fast ions, independently of toroidal rotation. However, the energy confinement is improved with the CO-directed toroidal momentum source at H-mode plasmas with small ripple loss.

Journal Articles

Fatigue assessment of the ITER TF coil case based on JJ1 fatigue tests

Hamada, Kazuya; Nakajima, Hideo; Takano, Katsutoshi*; Kudo, Yusuke; Tsutsumi, Fumiaki*; Okuno, Kiyoshi; Jong, C.*

Fusion Engineering and Design, 75-79, p.87 - 91, 2005/11

 Times Cited Count:8 Percentile:50.83(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Effective bending strain estimated from $$I$$$$_{c}$$ test results of a D-shaped Nb$$_{3}$$Al CICC coil fabricated with a react-and-wind process for the National Centralized Tokamak

Ando, Toshinari*; Kizu, Kaname; Miura, Yushi*; Tsuchiya, Katsuhiko; Matsukawa, Makoto; Tamai, Hiroshi; Ishida, Shinichi; Koizumi, Norikiyo; Okuno, Kiyoshi

Fusion Engineering and Design, 75-79, p.99 - 103, 2005/11

 Times Cited Count:1 Percentile:10.9(Nuclear Science & Technology)

no abstracts in English

Journal Articles

On the poloidal localization and stability of multi-faceted asymmetric radiation from the edge (MARFE)

Chankin, A. V.

Physics of Plasmas, 11(4), p.1484 - 1492, 2004/04

 Times Cited Count:9 Percentile:30.39(Physics, Fluids & Plasmas)

no abstracts in English

JAEA Reports

Fast ion loss calculation in the ripple compensation magnetic field by ferritic steel insertion using the FEMAG/OFMC code

Urata, Kazuhiro*; Shinohara, Koji; Suzuki, Masanobu*; Kamata, Isao*

JAERI-Data/Code 2004-007, 45 Pages, 2004/03


As the toroidal magnetic field generated by discrete TF coils involves magnetic field ripple, the fast ion loss is induced to damage vacuum vessel in tokamaks. An idea of ripple compensation using ferromagnetic is proposed. Since low activation ferritic steel have low activation and thermal conduction properties, the ferritic steel is planned to install in tokamak reactors. Installation of ferritic steel plates with toroidal symmetry is effective to compensate ripple, however in the actual devices it is difficult for interference with other components. Besides the first wall shapes are often asymmetric. So it is better to treat toroidal asymmetry to evaluate the ripple induced loss in the actual devices. For the purpose, magnetic field calculation code considering ferritic steel; FEMAG(FErrite generating MAGnetic field)has been speeded up. On the basis of this magnetic field data, OFMC (Orbit Following Monte Carlo) has been upgraded to treat toroidal asymmetry. The use of FEMAG/OFMC, applications to the JFT-2M experiments, and the national centralized tokamak facility are reported.

Journal Articles

A New intelligent coil current control system combined with a synchronous generator and a diode rectifier

Shimada, Katsuhiro; Omori, Yoshikazu; Furukawa, Hiroshi*; Terakado, Tsunehisa; Matsukawa, Makoto; Kurihara, Kenichi

Proceedings of International Conference on Electrical Engineering 2004 (ICEE 2004), p.777 - 781, 2004/00

We developed a new coil current control system for a power supply that consists of a synchronous generator and diode rectifiers. Test results are reported for the toroidal field coil power supply of JT-60, a world-class tokamak-type fusion device. This coil current control system has been designed to improve the control flexibility of the plasma discharge, and to introduce new functions. A state feedback control method is adopted to control coil current. Limit functions for the generator field current, the generator output voltage, and the toroidal field coil voltage have been added to the original coil current control system. Moreover, the abnormal state detection function of a coil is implemented for safety. The developed new intelligent control system has been tested and its performance was confirmed.

Journal Articles

Development of a Nb$$_{3}$$Al conductor for toroidal field coils

Koizumi, Norikiyo; Ando, Toshinari*; Nakajima, Hideo; Matsui, Kunihiro; Sugimoto, Makoto; Takahashi, Yoshikazu; Okuno, Kiyoshi; Kizu, Kaname; Miura, Yushi; Tsuchiya, Katsuhiko; et al.

Proceedings of 20th IEEE/NPSS Symposium on Fusion Engineering (SOFE 2003), p.419 - 422, 2003/10

Nb$$_{3}$$Sn cConductors have already been developed for the TF coils operating at 13 T. However, the critical current of Nb$$_{3}$$Sn degrades due to a strain, and the amount of degradation becomes larger when the magnetic field increases, which set a limit of the Nb$$_{3}$$Sn application to a large coil at around 13 T. Nb$$_{3}$$Al is considered, therefore, to be a next generation superconductor, since the critical current of Nb$$_{3}$$Al is superior to that of Nb$$_{3}$$Sn and less sensitive against strains. JAERI has been developing Nb$$_{3}$$Al conductor since 80s. As the first step, mass production technique of Nb$$_{3}$$Al strands was established. In the second step, coil fabrication technique was developed and could successfully be charged to the nominal point of 13 T and 46 kA. From these advantages, JAERI is also promoting R&D activities to develop Nb$$_{3}$$Al TF coils for JT-60SC. The prototype Nb$$_{3}$$Al conductor has already been made. A D-shaped coil was fabricated and successfully tested. These activities constitute the basic approaches to develop TF coils whose operating field is expected to be around 16 T.

Journal Articles

Current point formation and magnetic reconnection process in nonlinearly destabilized double tearing modes

Ishii, Yasutomo; Azumi, Masafumi; Kishimoto, Yasuaki

Physics of Plasmas, 10(9), p.3512 - 3520, 2003/09

 Times Cited Count:9 Percentile:29.72(Physics, Fluids & Plasmas)

no abstracts in English

Journal Articles

Development of a Nb$$_{3}$$Al conductor to be applied to a fusion reactor and its application to a large superconducting coil

Koizumi, Norikiyo; Okuno, Kiyoshi; Nakajima, Hideo; Ando, Toshinari*; Tsuji, Hiroshi

Teion Kogaku, 38(8), p.391 - 398, 2003/08

no abstracts in English

Journal Articles

Evaluation of the critical current performance of a Nb$$_{3}$$Al insert

Koizumi, Norikiyo; Nunoya, Yoshihiko; Takayasu, Makoto*; Sugimoto, Makoto; Nabara, Yoshihiro; Oshikiri, Masayuki*; CS Model Coil Test Group

Teion Kogaku, 38(8), p.399 - 409, 2003/08

A Nb$$_{3}$$Al insert was developed to demonstrate the applicability of a Nb$$_{3}$$Al conductor and wind-and-react method to a TF coil of a fusion reactor by artificially applying 0.4% bending strain to the conductor after its heat treatment. The critical current test results show that the effective strains applied to the strands is almost zero. Then, the validity of the react-and-wind method was demonstrated. In addition, while an unexpected strain, which was proportional to electromagnetic force, was observed in the same scale Nb$$_{3}$$Sn conductor, such strain did not exist in the Nb$$_{3}$$Al conductor. This shows a Nb$$_{3}$$Al conductor is suitable to the application to large magnets, such as the TF coil. Furthermore, the effect of the current transfer among the strands on the critical current evaluation is studied by developing a numerical analysis code, KORO. The results figure out that the critical current of a large cable-in-conduit conductor can be easily evaluated assuming the uniform current distribution if the conductance among the strands is 10E5 S/m or less.

Journal Articles

Development of the Nb$$_{3}$$Al D-shaped coil fabricated by react-and-wind method for JT-60 superconducting Tokamak

Kizu, Kaname; Miura, Yushi; Tsuchiya, Katsuhiko; Koizumi, Norikiyo; Matsui, Kunihiro; Ando, Toshinari*; Hamada, Kazuya; Hara, Eiji*; Imahashi, Koichi*; Ishida, Shinichi; et al.

Proceedings of 6th European Conference on Applied Superconductivity (EUCAS 2003), p.400 - 407, 2003/00

Toroidal field coils (TFC) of the JT-60SC consist of 18 D-shape coils. The maximum magnetic field is 7.4 T at an operational current of 19.4 kA. An advanced Nb$$_{3}$$Al superconductor was developed for the TFC conductor material in JAERI. The Nb$$_{3}$$Al has lower strain sensitivity on superconducting performances, and allows us to fabricate the TFC by react-and-wind (R&W) method that makes that the coil fabrication with high reliability becomes easier and the fabrication cost becomes lower. To demonstrate the coil fabrication by R&W method, a two-turn D-shape coil was developed. The D-shape coil was tested at 4.3-4.4K and 7-12T. Measured critical current (Ic) was 30 kA at 7.3 T and 4.4 K. Using the measured conductor and strand Ic values, the strain of the conductor was estimated to be -0.6%. The Ic-B-T characteristic expected by an empirical equation substituting this strain shows that the required temperature margin for TFC is satisfied. Thus, the R&W method was demonstrated to be the applicable fabrication method of the TFC.

Journal Articles

Critical current test results of 13T-46kA Nb$$_{3}$$Al cable-in-conduit conductor

Koizumi, Norikiyo; Takahashi, Yoshikazu; Nunoya, Yoshihiko; Matsui, Kunihiro; Ando, Toshinari; Tsuji, Hiroshi; Okuno, Kiyoshi; Azuma, Katsunori*; Fuchs, A.*; Bruzzone, P.*; et al.

Cryogenics, 42(11), p.675 - 690, 2002/11

 Times Cited Count:23 Percentile:65.65(Thermodynamics)

In the framework of ITER-EDA, a 13 T – 46 kA Nb$$_{3}$$Al conductor with stainless steel jacket has been developed to demonstrate applicability of an Nb$$_{3}$$Al conductor with react-and-wind technique to ITER-TF coils. The critical current performances of the Nb$$_{3}$$Al conductors were studied to verify that the conductor achieves the expected performance and 0.4% bending strain does not originate degradation. The critical currents were measured at the background magnetic fields of 7, 9, 10 and 11 T at the temperatures from 6 to 9 K. The expected critical currents is calculated using the developed model and the calculation results indicate that the experimental results showed good agreement with the expected critical currents. Accordingly, we can conclude that the fabrication process of this conductor was appropriate and the applicability of the react-and-wind technique was demonstrated.

Journal Articles

Development of ITER toroidal field insert; International collaboration with Russia

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.

Journal Articles

Electromagnetic phenomenon in superconducting magnet for fusion facility; Forced flow superconducting magnet

Hamada, Kazuya; Koizumi, Norikiyo

Purazuma, Kaku Yugo Gakkai-Shi, 78(7), p.616 - 624, 2002/07

In the Tokamak type fusion reactor design, a forced flow superconducting coil is applied from the viewpoint to high magnetic field, high withstand voltage performance and large electromagnetic force. In the forced flow magnets, it is well known that various electromagnetic phenomena are occurred by zero resistance and diamagnetic effect of superconductor and complicated structure of cable in conduit conductor (CICC). In the R&D of CICC, the study of hysteresis losses and coupling losses CICC have a lot of progress. For example, using the optimization of filament arrangement in superconducting strand and control of contact resistance of strand, ITER model coil project have a large achievement.

Journal Articles

Coherent magnetic fluctuations ergodized ELMy H-mode in the JFT-2M tokamak

W.Liu*; Miura, Yukitoshi; JFT-2M Group

Purazuma, Kaku Yugo Gakkai-Shi, 74(7), p.753 - 757, 1998/07

no abstracts in English

Journal Articles

Shielding analysis for toroidal field coils around exhaust duct in fusion experimental reactors

Sato, Satoshi; Takatsu, Hideyuki; *; Seki, Yasushi

J. Fusion Eng. Des., 30(3), p.1076 - 1080, 1996/12

no abstracts in English

Journal Articles

ITER superconducting-magnets systems

J.R.Miller*; L.Bottura*; Koizumi, Koichi; A.Kostenko*; J.Minervini*; N.Mitchell*; Tada, Eisuke; Yoshida, Kiyoshi

IAEA-CN-53/F-3-7, 7 Pages, 1990/00

no abstracts in English

Journal Articles

Development of the proto-type conductors and design of the test coil for the fusion experimental reactor

Nishi, Masataka; Takahashi, Yoshikazu; Isono, Takaaki; *; Yoshida, Kiyoshi; Koizumi, Koichi; Tada, Eisuke; Tsuji, Hiroshi; Okuno, Kiyoshi; Ando, Toshinari; et al.

Proc. of IEEE 13th Symp. on Fusion Engineering,Vol. 1, p.780 - 783, 1990/00

no abstracts in English

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