[Table of Contents]

Plasma and Fusion Research

Volume 7, 2403143 (2012)

Regular Articles

Analysis of Contact Lengths of Strands with Cu Sleeves in CICC Joints
Shinobu NAKAZAWA, Daichi ARAI, Toshiya MORIMURA, Daisuke MIYAGI, Makoto TSUDA, Takataro HAMAJIMA, Tsuyoshi YAGAI1), Yoshihiko NUNOYA2), Norikiyo KOIZUMI2), Kazuya TAKAHATA3) and Tetsuhiro OBANA3)
Tohoku University, 6-6-05 Aoba Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan
1)
Sophia University, 7-1 Kioicho, Chiyoda-ku, Tokyo 102-8554, Japan
2)
Japan Atomic Energy Agency, 801-1 Mukoyama, Naka., Ibaraki 311-0193, Japan
3)
National Institute for Fusion Science, 322-6 Oroshi-cho, Toki, Gifu 509-5292, Japan
(Received 8 December 2011 / Accepted 19 July 2012 / Published 15 October 2012)

Abstract

Cable-in-Conduit-Conductor (CICC) is used for the international thermonuclear fusion experimental reactor (ITER) toroidal field (TF) coils. But the critical current of the CICC is measured lower than expected one. This is partly explained by unbalanced current distribution caused by inhomogeneouscontact resistances between strands and copper sleeves at joints. Current density in some strands reaches the critical under unbalanced current, and the quench is occurred under smaller transport current than expected one. In order to investigate the contact resistances, we measure the three-dimensional positions of all strands inside the CICC for Large Helical Device (LHD) poloidal field (PF) outer vertical (OV) coil, and evaluate contact parameters such as number and lengths of strands which contact with a copper sleeve. Then, we simulate the strand positions in the CICC using the numerical code which we developed, and compare the contact parameters which evaluated from the measured strand positions and the simulated ones. It is found that the both results are in good agreement, and the developed numerical model is useful for evaluation of the contact parameters. We apply the code to various CIC conductor joints to obtain optimal joint parameters.

Keywords

cable-in-conduit conductor, contact length, joint, twist pitch

DOI: 10.1585/pfr.7.2403143

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References

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This paper may be cited as follows:

Shinobu NAKAZAWA, Daichi ARAI, Toshiya MORIMURA, Daisuke MIYAGI, Makoto TSUDA, Takataro HAMAJIMA, Tsuyoshi YAGAI, Yoshihiko NUNOYA, Norikiyo KOIZUMI, Kazuya TAKAHATA and Tetsuhiro OBANA, Plasma Fusion Res. 7, 2403143 (2012).