https://www.google.com/amp/s/www.nytimes.com/2020/09/29/climate/nuclear-fusion-reactor.amp.html

  • Owl [he/him]
    ·
    4 years ago

    Fusion isn't that hard to do. A dedicated hobbyist with some disposable income can build a fusor in their bedroom.

    What's hard about fusion power is that, while the reaction itself generates more energy than it takes to start, it only happens under crazy high-energy conditions. The hobbyist version doesn't generate net power because it just uses a ton of energy to make those conditions for a tiny bit of fusion.

    Thermonuclear bombs (ps we have had fusion nukes for decades) create the conditions for fusion inside of the blast of a nuclear fission bomb*. They generate net energy very briefly, and then that energy goes everywhere, which is the point, because it's a bomb.

    Nuclear power needs to sustain the conditions for fusion for a long time. Fusion itself generates net energy, so it should be able to use that energy to keep the conditions going. The most serious approaches involve keeping a lot of hot hydrogen plasma in one place for an extended period of time, it's just a matter of how to contain it. The sun does it with gravity. It's too hot to keep in a big metal box. Magnets work on it, but you need very big magnets, and the way plasma interacts with magnets is hideously complicated. The current best design for magnetic confinement is a tokamak - magnets holding plasma in the shape of a spinning donut.

    ITER is an attempt to build an absolutely gigantic tokamak, which should be able to generate net power. It'll take decades because ITER is extremely complicated and absolutely gigantic. It's almost certain to work so long as it keeps getting funding. It also won't solve anything under capitalism - we already don't build fission reactors because they take five years to build and that's not a fast enough profit.

    ITER has taken so long to design that, in the meantime, better magnets have been invented. Sparc is an attempt to build a much smaller reactor by taking advantage of stronger magnets. Sparc might work, and that'd be very convenient.

    *By the way, fission gets power by splitting very heavy elements, fusion gets power by fusing very light elements. The resting point where neither can generate power is iron.