Skip to Content
77 Mass Ave

A Workable Fusion Reactor

Cutting fusion down to practical size.

It’s an old joke that many fusion scientists have grown tired of hearing: Practical nuclear fusion power is just 30 years away—and always will be.

But now, that may no longer be true. New advances in magnet technology have enabled researchers at MIT to propose a new design for a practical compact tokamak fusion reactor—and it’s one that might be realized in as little as a decade, they say.

The new reactor uses coils of rare-earth barium copper oxide, a commercially available superconductor, to generate an extremely strong magnetic field. Introducing this material “just ripples through the whole design,” says Dennis Whyte, a professor of nuclear science and engineering and director of MIT’s Plasma Science and Fusion Center. “It changes the whole thing.”

The stronger magnetic field makes it possible to confine the superhot plasma—the electrically charged gas that feeds the fusion reaction—within a much smaller device than those previously envisioned. The reduction in size, in turn, makes the whole system less expensive and faster to build. The reactor concept, which uses a tokamak (doughnut-shaped) geometry that is widely studied, was developed by Whyte, PhD candidate Brandon Sorbom, and several other students. Their concept originated in a design class taught by Whyte and continued as a student-led project after the class ended.

The new reactor is designed for basic research on fusion and also as a potential prototype power plant that could produce significant power. “The much higher magnetic field allows you to achieve much higher performance,” says Sorbom.

Fusion reactors, which rely on the same nuclear reaction that powers the sun, force pairs of hydrogen atoms together to form helium, which releases enormous amounts of energy. The hardest part of designing a workable reactor has been confining the plasma while heating it to temperatures hotter than the cores of stars. This is where the magnetic fields are critical: they effectively trap the heat and particles in the hot center of the device.

The new superconductors make it possible to increase the power produced by about a factor of 10 compared with standard superconducting technology, Sorbom says. Right now, he adds, the reactor should be capable of producing about three times as much electricity as is needed to keep it running. The design could probably be improved to increase that proportion to about five or six times, he says, which would yield enough electricity for about 100,000 people. Until now, no fusion reactor has produced as much energy as it consumes.

Keep Reading

Most Popular

conceptual illustration of a heart with an arrow going in on one side and a cursor coming out on the other
conceptual illustration of a heart with an arrow going in on one side and a cursor coming out on the other

Forget dating apps: Here’s how the net’s newest matchmakers help you find love

Fed up with apps, people looking for romance are finding inspiration on Twitter, TikTok—and even email newsletters.

computation concept
computation concept

How AI is reinventing what computers are

Three key ways artificial intelligence is changing what it means to compute.

still from Embodied Intelligence video
still from Embodied Intelligence video

These weird virtual creatures evolve their bodies to solve problems

They show how intelligence and body plans are closely linked—and could unlock AI for robots.

We reviewed three at-home covid tests. The results were mixed.

Over-the-counter coronavirus tests are finally available in the US. Some are more accurate and easier to use than others.

Stay connected

Illustration by Rose WongIllustration by Rose Wong

Get the latest updates from
MIT Technology Review

Discover special offers, top stories, upcoming events, and more.

Thank you for submitting your email!

Explore more newsletters

It looks like something went wrong.

We’re having trouble saving your preferences. Try refreshing this page and updating them one more time. If you continue to get this message, reach out to us at customer-service@technologyreview.com with a list of newsletters you’d like to receive.