Regular Articles

Full Text / References

Split and Segmented-Type Helical Coils for the Heliotron Fusion Energy Reactor

Nagato YANAGI, Kiyohiko NISHIMURA, Gourab BANSAL¹⁾, Akio SAGARA and Osamu MOTOJIMA

National Institute for Fusion Science, 322-6 Oroshi-cho, Toki, Gifu 509-5292, Japan

1)

Institute for Plasma Research, Bhat, Gandhinagar, Gujarat, 382-428 India

(Received 9 January 2009 / Accepted 8 July 2009 / Published 26 March 2010)

Abstract

Configuration optimization is carried out for the heliotron-type fusion energy reactor FFHR. One of the important issues is to find sufficient clearances between the ergodic region outside the nested magnetic surfaces and blankets at the inboard side of the torus so that direct losses of alpha particles are minimized and the heat flux on the first walls is reduced. The latest design has a fairly large major radius R_c ∼ 17 m of the helical coils in order to satisfy this condition. It has been found, as an alternative design, that equivalent clearances are obtained with R_c = 15 m by employing a lower helical pitch parameter and splitting the helical coils in the poloidal cross-section at the outboard side. Furthermore, splitting the helical coils provides another modified configuration at R_c ∼ 17 m that ensures magnetic well formation in the fairly large nested magnetic surfaces with outward shifted configurations. From the engineering viewpoint, we propose that such helical coils be constructed by prefabricating half-pitch segments using high-temperature superconductors; the segments are then to be assembled on site with joints.

Copyright (c) 2010 The Japan Society of Plasma Science and Nuclear Fusion Research

Keywords

heliotron, FFHR, configuration optimization, split-type helical coils, high-temperature superconductor, segmented-type fabrication of helical coils

DOI: 10.1585/pfr.5.S1026

Full Text

PDF format (1.7Mbytes)

References

• [1] O. Motojima et al., Nucl. Fusion 47, S668 (2007).
• [2] A. Sagara et al., Fusion Eng. Des. 81, 2703 (2006).
• [3] A. Sagara et al., Fusion Eng. Des. 83, 1690 (2008).
• [4] S. Imagawa et al., J. Plasma Fusion Res. SERIES 5, 537 (2002).
• [5] T. Morisaki et al., Fusion Eng. Des. 81, 2749 (2006).
• [6] T. Watanabe et al., Nucl. Fusion 46, 291 (2006).
• [7] N. Yanagi et al., in Proceedings of 17th International Toki Conference (2007).
• [8] K. Nishimura and M. Fujiwara, Research Report of the Institute of Plasma Physics, Nagoya University, IPPJ-869 (1988).
• [9] K. Nishimura and M. Fujiwara, J. Phys. Soc. Jpn. 64, 1164 (1995).
• [10] H. Akao, T. Watanabe and K. Nishikawa, JSPS Report 63050027 (1988) 345 (in Japanese).
• [11] K. Uo, Nucl. Fusion 13, 661 (1973).
• [12] H. Yamada et al., Plasma Phys. Control. Fusion 49, B487 (2007).
• [13] K. Saito et al., Proceedings of 18th International Toki Conference (2008).
• [14] G. Bansal et al., Plasma Fusion Res. 3, S1049 (2008).
• [15] Y. Yamada et al., IEEE Trans. Appl. Supercond. 15, 2600 (2005).
• [16] A. Ibi et al., Physica C 445-448, 525 (2006).
• [17] H. Fukushima et al., Physica C 463-465, 501 (2007).
• [18] S. Imagawa, A. Sagara and Y. Kozaki, Plasma Fusion Res. 3, S1050 (2008).
• [19] K. Takahata et al., Fusion Eng. Des. 82, 1487 (2007).
• [20] G. Bansal et al., IEEE Trans. Appl. Supercond. 18, 1151 (2008).
• [21] K. Uo et al., Proc. 14th Symp. Fusion Techonol. 2, 1727 (1986).
• [22] H. Hashizume et al., Fusion Eng. Des. 63, 449 (2002).

This paper may be cited as follows:

Nagato YANAGI, Kiyohiko NISHIMURA, Gourab BANSAL, Akio SAGARA and Osamu MOTOJIMA, Plasma Fusion Res. 5, S1026 (2010).