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Ozeki, Takahisa; Yonekawa, Izuru*
Purazuma, Kaku Yugo Gakkai-Shi, 89(7), p.487 - 491, 2013/07
no abstracts in English
Yamamoto, Tsuyoshi; Yonekawa, Izuru*; Ota, Kazuya*; Hosoyama, Hiroki*; Hashimoto, Yasunori*; Wallander, A.*; Winter, A.*; Sugie, Tatsuo; Kusama, Yoshinori; Kawano, Yasunori; et al.
Fusion Engineering and Design, 87(12), p.2016 - 2019, 2012/12
Times Cited Count：2 Percentile：18.89(Nuclear Science & Technology)The ITER pulse scheduling system creates, approves and manage parameters that characterize plasma operation of ITER. JAEA analyzed requirements on the ITER plasma operations based on experience operating the JT-60U and designed essential functions. This system was designed to enable the change and reuse of parameters. The functions to support to check consistency between parameters and to assign parameter values are calculated by the system were proposed. These functions are useful to support operators.
Kitazawa, Sin-iti; Okayama, Katsumi*; Neyatani, Yuzuru; Sagot, F.*; Van Houtte, D.*; Abadie, L.*; Yonekawa, Izuru*; Wallander, A.*; Klotz, W.-D.*
Fusion Engineering and Design, 87(7-8), p.1510 - 1513, 2012/08
Times Cited Count：8 Percentile：54.86(Nuclear Science & Technology)In the ITER project, Reliability, Availability, Maintainability and Inspectability (RAMI) approach has been adopted for technical risk control to guide the design of components and the preparation for operation and maintenance. RAMI analysis of the ITER CODAC system, the central plant control system, was performed in the current design available in conceptual design phase. A functional breakdown was prepared in a bottom-up approach, resulting in the system being divided into 5 main functions and sub-functions. Criticality matrices highlight the risks of the different failure modes with regard to their probability of occurrence and the impact on the availability. Reliability block diagrams were prepared to estimate the reliability and availability of each function under operating conditions. The inherent availability of the mandatory functions for the control of plasma experiments with mitigations was calculated to be 99.2% that is higher than the project required value of 98.8%.
Yonekawa, Izuru; Sueoka, Michiharu; Hosoyama, Hiroki*; Kawamata, Yoichi; Suzuki, Takahiro; Kurihara, Kenichi
Fusion Engineering and Design, 81(15-17), p.1897 - 1903, 2006/07
Times Cited Count：2 Percentile：17.66(Nuclear Science & Technology)Recent years, plasma current profile (j-profile) control has been newly proposed to avoid instabilities in the high normalized-beta plasma. In particular, for the real-time profile feedback control, the control period should be roughly less than several tens of ms, including data communication among relating systems. In order to minimize data transfer time,the profile data being a function of time and position is required to decrease its data size for efficient data handling. A profile data,defined as 3-dimension time series data (q,R,Z,t), was reduced by introducing normalized minor radius rho in place of (R,Z). Data handling for profile control will be presented with their technical issues, together with computing hardware engineering.
Kurihara, Kenichi; Yonekawa, Izuru; Kawamata, Yoichi; Sueoka, Michiharu; Hosoyama, Hiroki*; Sakata, Shinya; Oshima, Takayuki; Sato, Minoru; Kiyono, Kimihiro; Ozeki, Takahisa
Fusion Engineering and Design, 81(15-17), p.1729 - 1734, 2006/07
Times Cited Count：13 Percentile：67.03(Nuclear Science & Technology)A large tokamak fusion device JT-60 is expected to explore more advanced tokamak discharge scenario towards the ITER and a future power reactor. We believe the following experimental issues are expected to be solved in JT-60. To clarify how to keep a steady-state plasma with high performance, and how to avoid plasma instabilities almost completely. By stimulus of this motivation, several essential development and modifications of plasma control and data acquisition systems have been performed in JT-60. In this report, we discuss the developments to improve the JT-60 plasma control and data acquisition systems. In addition, a future plasma control and data acquisition systems leading to a standard design for a power reactor is envisaged on the basis of the 20-year plasma operation experiences.
Takenaga, Hidenobu; Miura, Yukitoshi; Kubo, Hirotaka; Sakamoto, Yoshiteru; Hiratsuka, Hajime; Ichige, Hisashi; Yonekawa, Izuru*; Kawamata, Yoichi; Iio, Shunji*; Sakamoto, Ryuichi*; et al.
Fusion Science and Technology, 50(1), p.76 - 83, 2006/07
Times Cited Count：4 Percentile：31.58(Nuclear Science & Technology)no abstracts in English
Kurihara, Kenichi; Kawamata, Yoichi; Sueoka, Michiharu; Hosoyama, Hiroki*; Yonekawa, Izuru; Suzuki, Takahiro; Oikawa, Toshihiro; Ide, Shunsuke; JT-60 Team
Fusion Engineering and Design, 74(1-4), p.527 - 536, 2005/11
Times Cited Count：11 Percentile：60.83(Nuclear Science & Technology)Since tokamak magnetic fusion research has just made a step forward to an international collaborative project ITER, the existing tokamaks including JT-60 are expected to explore more advanced operation scenarios. To test those scenarios in the JT-60 experiment, the basic methods for understanding of plasma equilibrium have been developed. Some of them have been accomplished, and the other are being conducted as follows: (1) A complete plasma shape is precisely reproduced in real time. (2) Eddy current effects are considered for shape reproduction. (3) A plasma current profile in the poloidal cross-section is reproduced in real. (4) For long-pulse DT operation, a method is developed to correct the drifted signal of the integrator for a pick-up coil by employing distant sensor signals. In the symposium, those methods will be explained in detail with the experimental results at JT-60. On the basis of such discussion, we would like to envisage a future of plasma equilibrium control toward ITER and a fusion power plant.
Sueoka, Michiharu; Hosoyama, Hiroki*; Suzuki, Takahiro; Yonekawa, Izuru; Kurihara, Kenichi
Heisei-16-Nendo Osaka Daigaku Sogo Gijutsu Kenkyukai Hokokushu (CD-ROM), 4 Pages, 2005/03
no abstracts in English
Akasaka, Hiromi; Takano, Shoji*; Kawamata, Yoichi; Yonekawa, Izuru
Heisei-16-Nendo Osaka Daigaku Sogo Gijutsu Kenkyukai Hokokushu (CD-ROM), 4 Pages, 2005/03
no abstracts in English
Kawamata, Yoichi; Yonekawa, Izuru; Kurihara, Kenichi
Heisei-16-Nendo Osaka Daigaku Sogo Gijutsu Kenkyukai Hokokushu (CD-ROM), 4 Pages, 2005/03
no abstracts in English
Yonekawa, Izuru; Kawamata, Yoichi; Totsuka, Toshiyuki; Akasaka, Hiromi; Sueoka, Michiharu; Yoshida, Hidetoshi
Fusion Engineering and Design, 71(1-4), p.11 - 15, 2004/06
Times Cited Count：5 Percentile：36.03(Nuclear Science & Technology)The JT-60 control system based on workstation and VME-bus system features with UNIX system has been successfully performed at JT-60U advanced plasma experiment. The various hardware modifications and the adoption of the advanced plasma control algorithms have been continued to the JT-60 control system since its upgrade in 1991. The ZENKEI, supervisory control system, has entirely remodeled from its original 16 bits minicomputer and CAMAC system to the combination of workstation and VME-bus system configuration with Ethernet communication network system. The plasma control system executes real-time plasma equilibrium control command calculation within 250msec control cycle time. Each plant control subsystems are also modified along with same design concept to the ZENKEI. Currently, the minor modifications of the control system have been considered to realize longer pulse of discharge experiments without major change of the JT-60 equipment. Nearly 60 seconds of pulse length up to Ip=2MA, Bt=2T, PNBI=10MW(
30sec) plasma experiments will start from October in 2003.
Akasaka, Hiromi; Kawamata, Yoichi; Yonekawa, Izuru
Fusion Engineering and Design, 71(1-4), p.29 - 34, 2004/06
Times Cited Count：2 Percentile：17.54(Nuclear Science & Technology)The CAMAC hardware based timing system has been used to synchronizing pulse discharge sequential events and data collection of the interesting plasma phenomenon of the JT-60 plasma experiments. However, more flexible and intelligent timing system features with more state-of-the-art system is required corresponding to the increase of the requirement to realize more advanced plasma control and to minimize system maintenance cost. The combinations of the VME-bus system with high-speed data communication network by the reflective memory module and user-friendly application software based on MATLAB tools was selected for the new timing system. The new timing system provides the 50
sec master clock, various timing signal preparation logic, which is built into DSP module conjunction with discharge sequence event. Except clock pulse generator (CPG) module, no other special hardware-timing module is necessary for the new timing system.
Takano, Shoji*; Totsuka, Toshiyuki; Yonekawa, Izuru
KEK Proceedings 2003-16 (CD-ROM), 4 Pages, 2004/02
no abstracts in English
Oikawa, Toshihiro; Tsuchiya, Katsuhiko; Kurihara, Kenichi; Kawamata, Yoichi; Fukuda, Takeshi*; Fujita, Takaaki; Akasaka, Hiromi; Yonekawa, Izuru; Neyatani, Yuzuru
JAERI-Research 2003-027, 19 Pages, 2003/12
JAERI-Research-2003-027.pdf:1.14MB
no abstracts in English
Yonekawa, Izuru
Nihon Genshiryoku Gakkai-Shi, 45(10), p.650 - 651, 2003/10
no abstracts in English
Akasaka, Hiromi; Kawamata, Yoichi; Yonekawa, Izuru
Heisei-14-Nendo Tokyo Daigaku Sogo Gijutsu Kenkyukai Gijutsu Hokokushu, p.356 - 358, 2003/03
no abstracts in English
Kawamata, Yoichi; Yonekawa, Izuru; Kurihara, Kenichi; Sakakibara, Satoru*; Nishimura, Kiyohiko*
Annual Report of National Institute for Fusion Science; April 2002 - March 2003, 59 Pages, 2003/00
no abstracts in English
Yonekawa, Izuru; Kawamata, Yoichi; Totsuka, Toshiyuki; Akasaka, Hiromi; Sueoka, Michiharu; Kurihara, Kenichi; Kimura, Toyoaki; JT-60U Team
Fusion Science and Technology (JT-60 Special Issue), 42(2-3), p.521 - 529, 2002/09
Times Cited Count：5 Percentile：35.17(Nuclear Science & Technology)The present status of JT-60 control system is reported including its original design concept, the progress of the system and various modifications since JT-60 upgrade. This control system has features of a functionally distributed and hierarchical structure, using CAMAC interfaces at the beginning, which are replaced to versatile module Europe (VME)-bus interfaces later, and a protective interlock system composed of both software and hard-wired interlock logics. Plant monitoring and control are performed by efficient data communication through CAMAC highways and Ethernet with TCP/IP protocols. Sequential control of a plasma discharges are executed by a combination of a remodeled VME-bus system and a timing system. At real-time plasma control system and a human interface system have been continuously modified corresponding to the progress of JT-60 experiments.
Kawamata, Yoichi; Kurihara, Kenichi; Yonekawa, Izuru
Heisei-13-Nendo Denki Gakkai Genshiryoku Kenkyu Shiryo (NE-01-13), p.25 - 30, 2002/09
no abstracts in English
Totsuka, Toshiyuki; Akasaka, Hiromi; Sueoka, Michiharu; Takano, Shoji*; Yonekawa, Izuru
Fusion Engineering and Design, 60(3), p.409 - 414, 2002/06
Times Cited Count：2 Percentile：17.42(Nuclear Science & Technology)no abstracts in English
