Magnets for fusion energy: A revolutionary manufacturing method developed

July 25, 2014
This is the cross-section of the conductor sample. Credit: National Institutes of Natural Sciences

The National Institute for Fusion Science (NIFS), of the National Institutes of Natural Sciences (NINS) in Japan, has achieved an electrical current of 100,000 amperes, which is by far the highest in the world, by using the new idea of assembling the state-of-the-art yttrium-based high-temperature superconducting tapes to fabricate a large-scale magnet conductor.

NIFS is undertaking the development of a high-temperature superconducting coil that is appropriate for the fusion reactor magnet. Using the state-of-the-art yttrium-based high-temperature superconducting tapes which have been developed and produced in Japan through the new thinking that simply stacks the tapes, NIFS manufactured a conductor of exceptional mechanical strength. For the conductor joints, which are important for the production of the large-scale coils, NIFS developed low-resistance joint technology through collaborative research with Tohoku University. As a result of the prototype conductor test, at the absolute temperature of 20 degrees Kelvin (minus 253 degrees Celsius) the electrical current exceeds 100,000 amperes. The overall current density exceeds 40 A/mm2 including the jackets, and this value is of practical use for manufacturing large-scale fusion reactor magnets. This result is of global importance. We use 54 yttrium-based high-temperature superconducting tapes. Each tape is 10 mm in width and 0.2 mm in thickness.

This is the whole set of the conductor. Credit: National Institutes of Natural Sciences

The cross-section of the superconductor sample is shown in Fig.1. The flows only through this area. Together with the substrate used for this type of tape that is exceptional in strength and flexibility, by surrounding this area by a copper jacket and a stainless steel jacket an extremely strong conductor is produced. The whole set of the sample is shown in Fig.2. The current is induced by magnetic induction.

The revolutionary method by which the helical 's massive magnet is manufactured by sequentially connecting the short high-temperature superconductors has received much attention. Further, the large current-capacity high-temperature superconductor with simple stacking of yttrium-based tapes and the so-called "joint winding method" have also impacted the development of high-temperature superconducting magnets used in medical instruments and power-electric devices. Ripple effects are anticipated in the future.

Explore further: New World Record For Superconducting Magnet Set

More information: Yanagi, N., Ito, S., Terazaki, Y., Natsume, K., Tamura, H., Hamaguchi, S., Mito, T., Morikawa, J., Ogawa, Y, Iwakuma, M., Hashizume, H., Sagara, A., "Feasibility of HTS magnet option for fusion reactors", Plasma and Fusion Research, Vol.9 (2014) p. 1405013.

Yanagi, N., Terazaki, Y., Ito, S., Kawai, K., Seino, Y., Ohinata, T., Tanno, Y., Natsume, K., Hamaguchi, S., Noguchi, H., Tamura, H., Mito, T., Hashizume, H., Sagara, A.; "Progress of the design of HTS magnet option and R&D activities for the helical fusion reactor", IEEE Transactions on Applied Superconductivity Vol.24, No.3 (2014) p. 4202805.

Related Stories

New World Record For Superconducting Magnet Set

August 7, 2007

A collaboration between the National High Magnetic Field Laboratory at Florida State University and industry partner SuperPower Inc. has led to a new world record for a magnetic field created by a superconducting magnet.

CERN: World-record current in a superconductor

April 15, 2014

In the framework of the High-Luminosity LHC project, experts from the CERN Superconductors team recently obtained a world-record current of 20 kA at 24 K in an electrical transmission line consisting of two 20-metre long ...

Superconducting secrets solved after 30 years

June 17, 2014

(Phys.org) —A breakthrough has been made in identifying the origin of superconductivity in high-temperature superconductors, which has puzzled researchers for the past three decades.

Cambridge team breaks superconductor world record

June 26, 2014

A world record that has stood for more than a decade has been broken by a team led by University of Cambridge engineers, harnessing the equivalent of three tonnes of force inside a golf ball-sized sample of material that ...

Recommended for you

Rogue wave theory to save ships

July 29, 2015

Physicists have found an explanation for rogue waves in the ocean and hope their theory will lead to devices to warn ships and save lives.

Researchers build bacteria's photosynthetic engine

July 29, 2015

Nearly all life on Earth depends on photosynthesis, the conversion of light energy into chemical energy. Oxygen-producing plants and cyanobacteria perfected this process 2.7 billion years ago. But the first photosynthetic ...

Innovations from the wild world of optics and photonics

August 2, 2015

Traditional computers manipulate electrons to turn our keystrokes and Google searches into meaningful actions. But as components of the computer processor shrink to only a few atoms across, those same electrons become unpredictable ...

Quantum matter stuck in unrest

July 31, 2015

Using ultracold atoms trapped in light crystals, scientists from the MPQ, LMU, and the Weizmann Institute observe a novel state of matter that never thermalizes.

4 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

axemaster
5 / 5 (5) Jul 25, 2014
Impressive work. I look forward to the day they develop cheap, highly flexible high temperature superconductors, i.e. tapes or perhaps braided wires. Even without room temp superconductivity, these flexible versions would find many uses.
TheGhostofOtto1923
4.2 / 5 (5) Jul 25, 2014
Maybe tapes will make it easier to fabricate the complex coil shapes needed in stellerators.
http://www.ipp.mp...01/03_14
http://en.wikiped...periment
Tektrix
5 / 5 (2) Jul 25, 2014
Compare with "Bitter plate" construction, that is used in the highest continuous flux magnets: http://en.wikiped...romagnet
George_Rajna
Jul 28, 2014
This comment has been removed by a moderator.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.