Scientists Reach Nuclear Fusion Milestone

By Carl Engelking | February 12, 2014 5:15 pm
A scientist works in the firing chamber of the National Ignition Facility at Lawrence Livermore National Laboratory in California. Credit: Lawrence Livermore National Laboratory, Lawrence Livermore National Security, LLC, and the Department of Energy

A scientist works in the firing chamber of the National Ignition Facility. Credit: Lawrence Livermore National Laboratory, Lawrence Livermore National Security, LLC, and the Department of Energy

Scientists are a step closer to harnessing the same force that powers the sun, nuclear fusion, to someday pave the way for reactors that could provide an almost-infinite and carbon-free source of energy for Earth.

There is a long way to go before nuclear fusion reactors power our homes, but researchers at the Lawrence Livermore National Laboratory in California reached an important milestone: For the first time, scientists produced a fusion reaction that yielded more energy than went into it.

The study’s lead physicist Omar Hurricane explained the milestone to Reuters today: “Really for the first time anywhere, we’ve gotten more energy out of this fuel than was put into the fuel. And that’s quite unique. And that’s kind of a major turning point, in a lot of our minds.”

Laser Focused

Nuclear fission, the kind used in nuclear reactors today, involves splitting atoms in two. Fusion, on the other hand, melds two into one. It’s been a long-sought-after energy source because it is the most efficient power-producing process we know of. Hydrogen is a plentiful fuel, and unlike fission, fusion reactions create minimal waste.

The setup was this: 192 lasers were aimed at a pea-sized gold cylinder, called a hohlraum, inside of which was a 2-millimeter pellet filled with deuterium and tritium (isotopes of hydrogen). When turned on, the laser beams struck the can’s inner walls and released X-rays that crushed the pellet to a fraction of its original size. The intense pressure caused the two isotopes’ nuclei to fuse, setting off a chain reaction that generated temperatures hotter than those on the sun’s surface. 

Thus scientists essentially created a tiny star for about one second, until it blew to pieces. The total energy yield was tenfold that of previous laser fusion experiments, and for the first time, it exceeded the amount of laser energy that entered the fuel pellet. Still, the output was only 1/100th of the break-even point known as ignition, when total energy output exceeds total input, due to much of the laser beams’ energy getting absorbed by the hohlraum. The findings were published today in Nature.

Fusion’s Future

Mark Herrman, director of the Pulse Power Sciences Center at the Sandia National Laboratory, told the Washington Post nuclear fusion is still a long way from becoming a viable power source for civilization:

“They’ve got a factor of about 100 to go. We want a lot of fusions. They made 5 million billion fusions, but we want more than that. We want 100 times than what they made.”

To reach ignition, researchers need to compress the fuel pellet to a nearly perfect spherical implosion, which is what makes fusion reactions so difficult. Altering the shape of the gold canister, and ramping up the pressure from 150 gigabars — 150 billion atmospheres of pressure — to about 300 giagabars could help achieve ignition.

Still, can people expect to see the first nuclear fusion power plan in their lifetimes? Hurricane told Reuters he honestly doesn’t know:

“I wish I could put a date on it. But it really is (just) research. And, you know, although we’re doing pretty good, we’d be lying to you if we told you a date.”

CATEGORIZED UNDER: Space & Physics, Technology, top posts
MORE ABOUT: energy, physics
  • http://www.1reniernel.com/ Renier Nel

    Ever thought of firing the pellets as a neverending string into the focal point of the lasers? Why not tap the energy as pulses until we can achieve ignition and contain continual fusion?

    • KoKotheTalkingApe

      That is already the plan. There is no sustained fusion, except in the center of a star.

      • W Schlamilch

        Well people, the military and the politicians will be the first users of
        this enormous power. They will not hesitate to immediately make
        a new destructive weapon as always has been the case with the
        discovery of new energies. Please, read books about the subject
        if you are not blinded by admiration for those scientists.Their slogan is:
        we just invent, the responsibility is not ours.

        • LeeKrystek .

          Well, for the last 50 years we’ve had powerful fusion weapons (H-bombs). We already know who to use fusion to level a city. This research is to answer the question of whether we can power a city with it.

        • KoKotheTalkingApe

          Welcome to 1960!

    • John Holroyd

      Thanks, we never would have thought of that without you,

  • http://www.1reniernel.com/ Renier Nel

    Infinity power can be approached by firing two lasers precisely aimed at one another from an exact distance. Oscillating laser pulse(s) focus on a common center point by cooled lenses from both sides. The pellets is then shot into the focal point at very high speed. Limitations seem to be the timing and speed of the pellet, and the lasering material medium itself.

    • John Holroyd

      Infinity is quite a lot of power. What kind of bottle should we keep it in?

      • Jorge

        Excellent comment.

  • http://blogs.discovermagazine.com Longmire

    The spherical path may be ideal but with current technology it would be easier to design a rotating cone which narrows (kind of like a seashell) that funnels the hydrogen to a center point where the lasers can then be focused at it. If the final “beam” of hydrogen were only allowed one outlet Then pressure could be created and lasers would only have to be on one side of the plane. Might sound like gibberish but look at the center of our galaxy, which spins around the center and emits a huge amount of energy from the center point which was considered a black hole but now doubt has been raised.

  • Muell Halde

    Not much mention of the radioactive byproducts or other hazards of this technique. Or where they’ll find enough deuterium or tritium to scale it up. But suppose someone does find a fuel source for this…and they set up the reactor somewhere in outer space, close enough to Earth that they can beam the energy home and far enough away leave all the dangerous stuff “out there”*1! Of course, they’ll have to scheme up a way to collect all that beamed energy and turn it into electricity so we can use it.*2

    Imagine. Remote Nuclear Fusion. An idea whose time has come…about 5 billion years ago.

    *1. The sun. *2. Photovoltaics.

    • John Holroyd

      I sure don’t want to be around when they start beaming gigawatts of energy back to earth, As for leaving the dangerous stuff out there. Just how far “out there” is safe and yet still close enough to beam it back?

    • John Holroyd

      Oh you meant the sun. It’s been done.

  • http://www.1reniernel.com/ Renier Nel

    There is a zillion years of global scale supply of this fuel in the water molecules of the oceans (heavy water) and as much as is needed can be claimed by ordinary physics such as distillation and final centrifuge.
    Fusion is amazing in the sense that intense power is aimed at the microcosm, which then unleash a profit of energy back towards the macrocosm..Humanity, who exist in the middle of this bi-directional abyss, then simply deviate the energy to spend some time with us. View a symbolic representation :

  • Hans Cummings

    Very cool, but I hope they don’t initiate a resonance cascade.

    • Antonio R. Sanchez

      Doc Oc?

      • pyrAmider

        Headcrab.

        • Andrew Berg

          They’re ready for you Dr. Freeman, in the test chamber…

      • Hans Cummings

        Half-Life. The picture of the facility reminds me of the test chamber at the beginning of Half-Life.

  • johndouglasdahl@gmail.com

    can’t imagine a “pellet” of hydrogen.
    unless the cavity of the hohlraum is called a “pellet”

  • godismyshadow

    Where is all this gold for the hohlraum cylinders coming from? There may be plenty of deuterium and tritium, but gold is relatively scarce. It seems like an expensive way to produce energy.

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