Performance of a Mechanical Bridge Joint for 30-kA-Class High-Temperature Superconducting Conductors

• Published in: IEEE transactions on applied superconductivity 2014-06, Vol.24 (3), p.1-5
• Main Authors: Ito, Satoshi, Kawai, Kenji, Seino, Yutaro, Ohinata, Tatsuya, Tanno, Yusuke, Yanagi, Nagato, Terazaki, Yoshiro, Natsume, Kyohei, Hamaguchi, Shinji, Noguchi, Hiroki, Tamura, Hitoshi, Mito, Toshiyuki, Sagara, Akio, Hashizume, Hidetoshi
• Format: Article
• Language: English
• Subjects: Applied sciences; Bridges; Coils; Conductors; Electric connection. Cables. Wiring; Electrical engineering. Electrical power engineering; Electromagnets; Electronic equipment and fabrication. Passive components, printed wiring boards, connectics; Electronics; Exact sciences and technology; Fusion reactors; High-temperature superconductors; Joints; Magnetic fields; power cable connecting; Power electronics, power supplies; Resistance; superconducting magnets; Various equipment and components
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/TASC.2013.2291157

In this report, we propose segment-fabricated high-temperature superconducting (HTS) magnets as candidates for the FFHR-d1 heliotron-type fusion reactor. The FFHR-d1 requires 100-kA-class superconducting conductors used at 12 T for a pair of helical coils. We fabricated and tested two 30-kA-class GdBCO conductors with bridge-type mechanical lap joints (mechanical bridge joints). This report details the design of the joint section and the experimental results of those samples, especially, those of their joints. We improved the geometry of the joint region in a second sample, based on our results from the first. The second sample has sufficiently low joint resistance (less than 5 nΩ), and we could apply 70 kA to it without causing quenching at the joint. Its joint resistance was also acceptable for providing the electric power required to run the cryoplant for the segmented HTS helical coils.