Design optimization of a HTS current lead with large current capacity for fusion application Original Research Article

Design study of a high temperature superconductor (HTS) current lead having a large current transportation capacity has been performed for thermonuclear fusion application on the basis of a 60 kA HTS current lead developed by Japan Atomic Energy Agency. The lead consists of copper and HTS parts, and the conductors of the parts are a forced flow cooled bundle and conduction cooled cylindrically arrayed stacks of silver-alloy sheathed Bi-2223 tapes for the copper and the HTS parts, respectively. The objective of the design study is to reduce cost for fabrication and operation of the HTS current lead by computing the optimum HTS operating temperature, where the total amount, including increase of fabrication cost and decrease of operating cost by adoption of HTS lead, is minimized. Results of the study show that HTS operating temperature of 75 K is optimum for 10,000 h operation and reduction by 1/5 of electric power consumption for a conventional lead can be achieved at the temperature.