Plan for Testing High-Current Superconductors for Fusion Reactors with A 15T Test Facility

Abstract

Fusion power plants need larger scale and higher field superconducting magnets than the ITER magnets. Therefore, higher current superconductors with high strength against strong electromagnetic forces are needed. In order to examine the superconducting properties of such large conductors in real conditions, we are preparing a new test facility that is equipped with a solenoid coil of the highest field of 13 T with the bore of 0.7 m, a pair of temperature-variable current leads, and a vacuum chamber for conductor samples. The highest field can be increased to 15 T by installing an additional coil with the cold bore of 0.6 m. Since the inlet temperature of the samples can be varied from 4.4 K to 50 K, it is possible to examine properties of advanced conductors at actual operating temperatures including high-temperature superconductors. We propose coil-shaped conductor samples instead of straight samples in order to apply electromagnetic hoop forces on the conductors to realize the real condition. A reference design of a sample for a cable-in-conduit conductor is provided.

Overview of Fusion Engineering Research in Japan Focusing on Activities in NIFS and Universities

“…A large bore (700 mm in diameter) and high field (13 T) magnet test facility 15 , a 9-T split coil, 75-kA DC power supply, and temperature-variable (4-50 K) refrigerator 16 have been installed for testing various superconducting conductor and coil samples. These facilities have been used for testing the performance of short HTS conductor samples 17 , the ITER-TF joint samples 18 , and the JT-60SA CS model and module coils 19 .…”

“…Also carried out was the analysis of the High Temperature High Flux Test Modules 126 .VI.Examples of the latest and ongoing researches Finally this paper outlines some of the latest and ongoing researches by NIFS collaboration with Universities and international partners, most of which have not been published in open journals.VI-1. Tests of HTS conductorsA 2-m HTS conductor named TSTC (Twist Stack Tape Cable)127 , developed at Massachusetts Institute of Technology (MIT), was installed into the large bore (700 mm in diameter) and high field (13 T) magnet test facility15 in NIFS, and the tests were launched in September 2018. The tests have been carried out without and with application of magnetic field of 5T at temperature of < 30 K.VI-2.…”

Conductor and joint test results of JT-60SA CS and EF coils using the NIFS test facility

“…Consequently, the joint tests of the ITER TF have been conducted using the NIFS test facility since 2013 [27]. In the future, we expect to use the NIFS test facility for the developments of conductor and joint aiming to the DEMO nuclear fusion power plant, provided that the required magnetic field strength is within 9 T. Additionally, at present, we are constructing a new test facility which can generate a high magnetic field up to 13 T using a superconducting solenoid coil, the bore of which is 0.7 m [28]. Using the new test facility, the conductor development for the DEMO will be accelerated.…”

Study on Configuration of Conductor Samples for 13 T - 700 mm Test Facility

“…The degradation should be more serious in the higher field and the higher current conductors. Therefore, a 13 T test facility with a 700 mm cold bore [4] and with 50 kA current leads has been prepared for the research of high-field and high-current superconductors. In order to attain sufficient length of testing region and to apply electromagnetic hoop stress on the superconductors, we propose a coil-shaped conductor sample of few turns, as shown in Fig.…”