[Table of Contents]

Plasma and Fusion Research

Volume 9, 3405086 (2014)

Regular Articles

Bridge-Type Mechanical Lap Joint of a 100 kA-Class HTS Conductor having Stacks of GdBCO Tapes
Satoshi ITO, Yutaro SEINO, Nagato YANAGI1), Yoshiro TERAZAKI2), Akio SAGARA1) and Hidetoshi HASHIZUME
Department of Quantum Science and Energy Engineering, Graduate School of Engineering, Tohoku University, 6-6-01-2 Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8579, Japan
1)
National Institute for Fusion Science, 322-6 Oroshi-cho, Toki, Gifu 509-5292, Japan
2)
The Graduate University for Advanced Studies, 322-6 Oroshi-cho, Toki, Gifu 509-5292, Japan
(Received 21 November 2013 / Accepted 25 April 2014 / Published 10 June 2014)

Abstract

In this paper, we reported design, fabrication and test of a prototype 100-kA-class high-temperature superconducting (HTS) conductor, especially for joint section, to be used for segmented HTS helical coils in the FFHR-d1 heliotron-type fusion reactor. The conductor has a geometry of three rows and fourteen layers of Gadolinium Barium Copper Oxide HTS (GdBCO) tapes embedded in copper and stainless steel jackets and has a joint section with bridge-type mechanical lap joint. We introduced improved method to fabricate the joint based on pilot experiments and we were able to apply a current of ∼ 120 kA at 4.2 K, 0.45 T to the sample without quench at joint. The obtained joint resistance was ∼ 2 nΩ, which was lower than our previous data. Though joint resistance increased with a rise in current and magnetic field, predicted joint resistance in the environment of actual helical coil in the FFHR-d1 was small enough to properly run the cryoplant of the reactor.

Keywords

high-temperature superconductor (HTS), REBCO, fusion reactor, helical reactor, FFHR-d1, mechanical joint, joint resistance, remountable HTS magnet, segmented HTS magnet

DOI: 10.1585/pfr.9.3405086

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This paper may be cited as follows:

Satoshi ITO, Yutaro SEINO, Nagato YANAGI, Yoshiro TERAZAKI and Akio SAGARA, Plasma Fusion Res. 9, 3405086 (2014).