The Verge: “Nuclear fusion power research passes milestone with ‘fusion ignition’”

In this case, at 1:03AM local time on December 5th, the national laboratory used 192 powerful laser beams to hit a solid target of hydrogen isotopes that’s only about the size of a peppercorn. The target is enclosed in a meticulously crafted diamond shell.

Today’s shells are almost perfectly round. They are 100 times smoother than a mirror, and they have a tiny tube attached to them that’s about a 50th the diameter of a hair through which the fuel is filled into the shell, said Michael Stadermann, Target Fabrication Program manager at Lawrence Livermore National Laboratory. As you can imagine, perfection is really hard, and so we’ve yet to get there — we still have tiny flaws on our shells, smaller than bacteria.

The experiment produced 3.15 megajoules of energy, about 50 percent more than the 2.05 megajoules the lasers used to trigger the reaction. By doing so, reaching a scientific energy breakeven, the researchers achieved what’s called “fusion ignition”.

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It’s a key milestone, but there are still some important caveats to note. One key point is that the DOE is basing this victory on just the output of the lasers, which are pretty inefficient. It takes 300 megajoules of energy from the grid just to get those two megajoules of laser energy. So today’s announcement hinges on a limited definition of “net energy gain”.

Justine Calma

The sensationalism and hype around science reporting is frankly getting tiresome. Though this article is a refreshing exception, most of the headlines and reactions around this news were calling it anything from ‘major breakthrough’ to ‘historic, innovative’, ‘landmark achievement’ to ‘astonishing scientific advance’ – starting with the official press release. We can suspect the reason has more to do with securing renewed funding for this research, but I still find this spectacle off-putting.

To create fusion ignition, the National Ignition Facility’s laser energy is converted into X-rays inside the hohlraum, which then compress a fuel capsule until it implodes, creating a high temperature, high pressure plasma.

The reality is that this project is still extremely far from any sort of commercial application of fusion power. The lasers used to ignite the hydrogen are so inefficient that it takes 100 times more energy to charge the lasers than the output of this first ignition. In a commercial system, the lasers would also need to fire in rapid sequence to maintain the reaction; extensive improvements of the setup are needed to achieve these two goals. The hydrogen targets have stringent requirements as well, and a working reactor would need a constant supply. Worst of all, the National Ignition Facility uses tritium for its fusion experiment, a hydrogen isotope extremely rare on Earth. In effect, this method of achieving fusion could prove a dead end because this crucial component is too scarce to make it commercially viable – or at the very least it would need to set up manufacturing and supply chains for tritium, which would further increase the costs of the energy produced.

My concern with the constant hyping is that, by presenting every incremental advancement as some sort of ‘huge breakthrough’ the public will either become jaded and ignore actual important technological developments, or they will assume this abundant and carbon-neutral energy source is much closer to practical application, thereby undermining efforts to combat climate change. Mastering fusion is vital for the future of energy generation on Earth, but let’s not entertain the illusion that this announcement is but a small step on a long and difficult road.