[Image above] The sun, a natural fusion reactor, may soon have competition from yttrium magnet-based fusion reactors. Credit: NASA
Despite decades of research, we don’t yet have fusion reactors generating clean, safe energy for mass consumption. Is that about to change?
Maybe, according to scientists at Japan’s National Institutes of Natural Sciences. They report the fabrication of a large-scale magnet conductor—generating a record-breaking electrical current of 100,000 amps—that could soon find use in fusion reactors.
The conductor is generating buzz because of its novel and simple manufacturing method. By simply stacking together 54 individual yttrium-based high-temperature superconducting tapes (10 mm wide by 0.2 mmm thick), the scientists fabricated a super powerful magnet conductor that reached temperatures down to 20 degrees K (-253 degrees C).
Because the tapes’ joints are rather important for large-scale coils, the NINS scientists paired up with colleagues at Tohoku University to produce a low-resistance “joint winding method” to secure the tapes together.
For the final conductor, the scientists surrounded the tapes with a copper jacket and a stainless steel jacket for insulation.
The conductor’s overall current density exceeds 40 A/mm2, which the scientists say “is of practical use for manufacturing large-scale fusion reactor magnets.”
The papers describing the work are: “Feasibility of HTS magnet option for fusion reactors” (DOI: 10.1585/pfr.9.1405013) published in Plasma and Fusion Research; and “Progress of the design of HTS magnet option and R&D activities for the helical fusion reactor” (DOI: 10.1109/TASC.2013.2292775) published in IEEE Transactions on Applied Superconductivity.