Design and development of high-temperature superconducting magnet system with joint-winding for the helical fusion reactor. (22nd April 2015)

• Record Type: Journal Article
• Authors: Yanagi, N.; Ito, S.; Terazaki, Y.; Seino, Y.; Hamaguchi, S.; Tamura, H.; Miyazawa, J.; Mito, T.; Hashizume, H.; Sagara, A.
• Is Part Of: Nuclear fusion. Volume 55:Number 5(2015:May)
• Publication Date: 2015-04-22
• Subjects: helical fusion reactor design -- high-temperature superconductor -- joint-winding; Nuclear fusion -- Periodicals; 621.48405
• DOI: 10.1088/0029-5515/55/5/053021
• Languages: English
• ISSNs: 0029-5515

Abstract

Abstract: An innovative winding method is developed by connecting high-temperature superconducting (HTS) conductors to enable efficient construction of a magnet system for the helical fusion reactor FFHR-d1. A large-current capacity HTS conductor, referred to as STARS, is being developed by the incorporation of several innovative ideas, such as the simple stacking of state-of-the-art yttrium barium copper oxide tapes embedded in a copper jacket, surrounded by electrical insulation inside a conductor, and an outer stainless-steel jacket cooled by helium gas. A prototype conductor sample was fabricated and reached a current of 100 kA at a bias magnetic field of 5.3 T with the temperature at 20 K. At 4.2 K, the maximum current reached was 120 kA, and a current of 100 kA was successfully sustained for 1 h. A low-resistance bridge-type mechanical lap joint was developed and a joint resistance of 2 nΩ was experimentally confirmed for the conductor sample.