Commonwealth Fusion Systems new high-temperature superconductor (HTS) cable can be engineered into magnets directly applicable to the high magnetic field approach to fusion. The new HTS cable, called VIPER, can carry over fifty thousand amps of current with magnetic fields over 10 Tesla.
Some fusion magnets need to turn on and off continually. VIPER was tested for thousands of on-off cycles and saw minimal performance degradation. VIPER’s main innovation is combining hundreds of individual tapes into a soldered, monolithic block of conductor.
A variant of VIPER will be used in an ARPA-E funded program to make a fast-ramping, high-field central solenoid magnet capable of initiating and sustaining plasma current in a tokamak device on its own. This magnet will lower the cost and complexity of commercial fusion power plants.
Here is the conclusion of the VIPER research paper:
VIPER cable demonstrates high mechanical strength, high cryostability, and rapid quench detection. Its performance is predictable and repeatable, allowing for high-confidence design. Its manufacturing process is simple and scalable to long lengths, and its simple, demountable joints allow for the repairability, access, maintenance and inspectability required by real-world applications. VIPER cable expands the performance boundaries of many critical energy generation and transmission technologies. It will, for example, enable the performance of large-scale high-field superconducting magnets to push well past 15 T. Such high-field superconducting magnet technology is presently enabling the high magnetic field pathway to accelerated fusion energy, including in the SPARC tokamak, an experiment seeking the demonstration of net fusion energy by the mid 2020’s, and slated to begin construction in 2021.
VIPER cable may also be relevant to high-energy physics detector magnets like those planned for the future circular collider. And it may find use in DC power cables, in the DC field winding components of electric motors and generators in the 10+ MW class, as well as in magnetic energy storage devices. This note has focused on the DC application of VIPER cable; however, AC applications are foreseen, and AC loss measurements were performed as part of the SULTAN tests. The results of these measurements and impact on VIPER cable suitability for AC applications will be reported in full in a future publication. Combined, these application categories are expected to drive significant scale up of HTS industry volumes and a corresponding reduction in cost. HTS demand in excess of 1000 km yr−1 is projected to drive the price of HTS tape below the $50/kA-m level over the next decade, greatly accelerating wide-scale application. We expect cost-effective VIPER cables to replace LTS cable in present and future applications and open new opportunities previously inaccessible to superconducting technology.
SOURCES – Commonwealth Fusion Systems, Superconductor Science and Technology
Written by Brian Wang, Nextbigfuture.com