Plasma and Fusion Research

Volume 20, 1405043 (2025)

Regular Articles

Progress in High-Temperature Superconducting WISE Conductors for Helical Fusion Reactors
Yoshiro NARUSHIMA1,2), Nagato YANAGI1,2), Yuta ONODERA1), Hirotaka CHIKARAISHI1,2), Tomosumi BABA1), Diego GARFIAS-DAVALOS2), Junichi MIYAZAWA3), Takuya GOTO3)
1)
National Institute for Fusion Science, National Institutes of Natural Sciences, Toki 509-5292, Japan
2)
SOKENDAI, Toki 509-5292, Japan
3)
Helical Fusion Co., Ltd., Tokyo 104-0061, Japan
(Received 22 April 2025 / Accepted 3 July 2025 / Published 12 September 2025)

Abstract

Applying high-temperature superconducting (HTS) conductors to the magnets of Helical fusion reactors, which require a higher degree of three-dimensionality compared to the magnets of tokamak devices, can enhance plasma performance by increasing fusion power. By stacking Rare-Earth Barium Copper Oxide (REBCO) tapes, winding them into specific shapes, and then impregnating them with low-melting-point metals, the strain on the tapes can be minimized. Using this method, a 2-m-long U-shaped WISE (Wound and Impregnated Stacked Elastic tapes) conductor was subjected to current testing at temperatures ranging from 6 to 20 K and magnetic fields of 8 T. The conductor had the capability of maintaining 40 kA for 8 s at 6 K, 8 T with an average engineering current density of 31 A/mm2, without a temperature rise or quench. Repeated tests at 20 K and 8 T with a maximum current of 22 kA showed no temperature increase, confirming the conductor’s mechanical robustness. In the preliminary stages of the energization test, an increase in voltage reminiscent of a quench was observed, even though the current was lower than the critical current value. However, this voltage was suppressed as the maximum value decreased with each repetition of energization. Such behavior is considered similar to a training effect and indicates the movement of REBCO tape inside the conductor.

Keywords

helical fusion reactor, REBCO, WISE conductor, fusion magnets

DOI: 10.1585/pfr.20.1405043

Full Text

PDF format (3.2Mbytes) PDF Download

References

  • [1] P. Bruzzone et al., Nucl. Fusion 58, 103001 (2018).
  • [2] H. Yamada et al., Nucl. Fusion 45, 1684 (2005).
  • [3] N. Yanagi et al., Nucl. Fusion 55, 053021 (2015).
  • [4] T. Mito et al., IEEE Trans. Appl. Supercond. 31, 4202505 (2012).
  • [5] S. Matsunaga et al., IEEE Trans. Appl. Supercond. 30, 4601405 (2020).
  • [6] J. Miyazawa et al., Nucl. Fusion 61, 126062 (2021).
  • [7] Y. Narushima et al., Plasma Fusion Res. 17, 2405006 (2022).
  • [8] Y. Narushima et al., J. Phys. Conf. Ser. 2545, 012009 (2023).
  • [9] S. Hamaguchi et al., 2016 Trans. Appl. Supercond. 26, 9500404 (2016).
  • [10] T. Mito et al., Fusion Eng. Des. 20, 233 (1993).
  • [11] J. Weiss et al., Supercond. Sci. Technol. 30, 014002 (2017).
  • [12] L. Hao et al., IEEE Trans. Appl. Supercond. 32, 5900505 (2022).
  • [13] H. Zohm et al., Plasma Phys. Control. Fusion 45, A163 (2003).
  • [14] Y. Narushima et al., Plasma Fusion Res. 8, 1071 (2009).