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Is fusion power right around the corner?

Nuclear fusion technology could herald a golden age of energy that will make the fossil fuel age look like the stone age! That’s right, limitless carbon-free energy for everyone, all thanks to the hard work of genius nuclear physicists and engineers! MIT recently announced that their fusion reactor project is only about 15 years away.

Last episode was a bummer. The world is closer than ever to total nuclear destruction. But! Nuclear fusion technology could herald a golden age of energy that will make the fossil fuel age look like the stone age! That’s right, limitless carbon-free energy for everyone, all thanks to the hard work of genius nuclear physicists and engineers! MIT recently announced that their fusion reactor project is only about 15 years away.

But what is fusion power? How does it work? Why has it taken so long to develop?

Nuclear fusion is the sam process that powers the sun. Deep in the sun’s core, hydrogen atoms are smashed together to form helium, and helium atoms are also smashed together, releasing tremendous amounts of energy. It’s basically gravity powered—the sun is so massive that gravity is strong enough to trigger fusion. How massive? About 333,000 times the mass of earth. And it’s huge, about 1.3 million earths could fit inside the sun. The amount of energy it produces is frankly inconceivable at 384.6 yottawatts (3.846×1026 W), or 9.192×1010 megatons of TNT—per second.

A fusion reactor fuses hydrogen atoms into helium atoms, but on a much, much smaller scale. That fusion produces heat, which is used to produce steam to turn a turbine, producing electricity. But it’s very difficult to start a sustained fusion reaction on earth. We don’t have the tremendous amounts of mass and gravity to work with, so scientists use other methods to heat hydrogen up to tremendous temperatures, over 100 million degrees Celsius. That’s about 10 times as hot as the sun. Of course, no material we know of could withstand such high temperatures, so fusion reactors use magnetic fields to contain the super-heated hydrogen.

Right now, it takes far more energy to start fusion than you get out of the reactor. MIT has been working on various reactors with the international community for years, but hasn’t hit the “break even” point—getting as much energy out of the thing as they put into it. Now they’re teaming with Commonwealth Fusion Systems to speed up development of a more efficient reactor. With this new research funding partner to add to the steady stream of government funding, MIT thinks they can make a fusion reactor that makes more energy than it uses within 15 years.

It’s not just money that’s making researchers so optimistic. Commonwealth Fusion Systems has engineered a new kind of magnet that’s far more efficient than the ones used now. The new high-temperature superconducting magnets are relatively inexpensive, easy to work with, and easy to make. They’re basically made of steel tape coated with a proprietary mix of yttrium-barium-copper oxide (YBCO).

So how does it all go together, what does a fusion reactor look like? MIT and fellow researchers in Europe are working on a Tokamak reactor design. Imagine a hollow steel donut and you’ll have a picture of what a Tokamak reactor looks like. Superheated hydrogen plasma flows around inside the donut, contained by a strong magnetic field. As the hydrogen fuses into helium, more hydrogen is injected into the reactor. Heat from the reaction makes steam for turbines.

It’s an extremely safe design. If the magnets fail, the hydrogen will cool and the fusion reaction will stop immediately. Fusion also doesn’t produce the same kind of radioactive waste that standard nuclear reactors produce. Fusion does produce radiation, but it’s trapped by the walls of the reactor. When a reactor is decommissioned, the walls will remain radioactive for 50-100 years. For comparison, nuclear waste from fission reactors can be deadly for thousands of years.

Fusion reactors use two different types of hydrogen isotopes for fuel—deuterium and tritium. Deuterium is basic hydrogen and can be easily distilled from water. Tritium is a slightly radioactive isotope of hydrogen consisting of one proton and two neutrons. It’s nearly impossible to find in nature, but can be produced in the Tokamak itself. Researchers will line the walls of the Tokamak with blankets of lithium. During the fusion reaction, stray neutrons will hit the lithium and produce tritium. Of course, lithium is used for all sorts of things, but ITER, the European fusion research consortium, estimates that there’s enough lithium on earth to make fusion reactors for 1,000 years. And that’s before we start mining asteroids.

ITER is the largest fusion reactor project on the planet. The seven-story facility in Southern France is a collaboration between 35 countries, including China, the European Union, India, Japan, Korea, Russia and the United States. MIT is sharing what it learns with ITER and the two are engaged in a friendly race to develop a sustainable Tokamak reactor. ITER estimates their reactor will come online by 2035.

But MIT and ITER aren’t the only ones working on fusion power. Lockheed Martin is developing a “compact” fusion reactors about the size of a shipping container. The reactor would theoretically churn out 100 megawatts, enough to power a city of about 100,000 people. They announced it way back in 2014, and said it’d be ready within a decade. The reactor uses a small dog bone-shaped vessel instead of a giant hollow donut. Additionally, a startup confusingly named Tokamak Energy in the UK is working on a compact spherical reactor that they claim will be about the same size and power output of the Lockheed Martin reactor. There’s a ton of renewed interest in fusion technology and more companies than ever are giving it a try.

Efficient fusion reactors would be unbelievably great for humanity. Cheap, low or no pollution energy for everyone. No drilling, no refining, no carbon emissions. Imagine building a fusion reactor near the ocean and letting it just chug along, sipping sea water and spitting out power day and night. It would only need a small amount of water for the fusion reaction and could even generate enough power to desalinate and purify ocean water for drinking and growing crops.

Of course there would be some environmental impact—there always is—but it would be much lower than fossil-fuel or fission reaction nuclear plants.

But why not just use solar, wind, geothermal, and wave power? Well, yes. We could use them all. Fusion reactors would be fantastic for shady climates like ours in Portland, OR, or to supplement renewable energy. They could also provide the additional power we’ll need when every car and truck on the road is electric.

Finally, small reactors like the one Lockheed Martin is building could be used on space stations or interplanetary ships, or to power future Martian and Europan colonies.

To learn more about MIT’s new fusion reactor research, click the link in the show notes to the MIT News website. Info about ITER can be found at iter.org More info about the Lockheed Martin reactor can be found on their website, lockheedmartin.com

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