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 Yagai, Yoshihiko Nunoya, Norikiyo Koizumi, Kazuya Takahata, Tetsuhiro Obana

Research output: Contribution to journalArticlepeer-review

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 inhomogeneous contact 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.

Original languageEnglish
Article number2403143
JournalPlasma and Fusion Research
Volume7
Issue numberSPL.ISS.1
DOIs
Publication statusPublished - 2012

Keywords

  • Cable-in-conduit conductor
  • Contact length
  • Joint
  • Twist pitch

ASJC Scopus subject areas

  • Condensed Matter Physics

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