Future Tense

So, Does Nuclear Fusion Work Now?

Sun in a Bottle author Charles Seife takes the National Ignition Facility’s big announcement down a peg.

The sun.
Braňo/Unsplash

To hear it from government researchers, a long-sought, frustratingly elusive, potentially world-shifting clean-energy milestone was finally reached this week: On Tuesday morning, the National Ignition Facility, or NIF, part of the California-based Lawrence Livermore National Laboratory, declared that it had achieved “fusion ignition,” which an official Department of Energy announcement described as “a major scientific breakthrough decades in the making that will pave the way for advancements in national defense and the future of clean power.”

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Why this is such a big deal: The goal of fusion is to replicate the kinds of nuclear reactions that power the sun, and co-opt it to create a potentially unlimited source of clean-burning energy. Achieving this goal has been elusive—trials kicked off about 70 years ago, but the results of these runs revealed that more energy goes into the process than is produced by the fusion reaction itself. As a result, both private and public research efforts in this space have lost funding due to impatience with the lack of viable results.

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Nevertheless, scientists have continued to push to make fusion work, because the payoff of fusion reactors across the globe would be huge: Endless and cheap green power could displace our fossil-fueled economy and cut carbon emissions, all without the radioactive waste that results from already-working fission reactions. No one thinks we’re there yet, but some politicians are gesturing that we’re, well, sort of close. A sample quote from Tuesday’s announcement, courtesy of U.S. Senate Majority Leader Chuck Schumer: “This astonishing scientific advance puts us on the precipice of a future no longer reliant on fossil fuels but instead powered by new clean fusion energy.”

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To talk through this breakout moment for nuclear fusion and whether it’s really all it’s being hyped up to be, I spoke with Charles Seife, a New York University journalism professor and author of the book Sun in a Bottle: The Strange History of Fusion and the Science of Wishful Thinking. (He also covered this week’s news for the Atlantic.) Our conversation has been condensed and edited for clarity.

Nitish Pahwa: In layperson’s terms, what happened with this fusion breakthrough, and what are the broader implications?

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Charles Seife: This has been an idea for the better part of a century: to take light atoms and smash them together hard enough so that they fuse and release energy. Scientists have known for years that this, on paper, would be a way of producing essentially unlimited amounts of energy. The problem is, it’s really hard to get that fusion reaction going, and we haven’t been able to do it except in an uncontrolled and violent manner—atomic weapons, hydrogen bombs.

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Since the 1950s, there’s been this quest to build a power reactor, an energy generator using fusion in the lab. Throughout that time, scientists thought that it was just a decade or two from being reality, but that keeps moving forward.

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This announcement is the first defensible claim of achieving net energy in a fusion reaction in the lab. There’s some asterisks near that, which are pretty important, but it is an agreed-upon threshold that scientists have been looking for for a couple of decades.

What do those caveats entail, in your view?

The first one is that the definition of ignition in this context means inertial confinement fusion, which I can explain a little bit. Ignition means that the amount of energy that comes out of fusion is more than the energy that is shined on the target by the lasers. So in this case, the lasers have contained about 2.1 megajoules of energy, and the fusing pellets produced about 3.15 megajoules, so more-energy-out-than-in ignition. That’s significantly higher than I expected, and makes for almost double NIF’s best shot previously.

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However, it takes a lot more energy to produce those laser beams than is contained in the laser beams themselves. In fact, it takes between 300 and 400 megajoules to produce a 2.1-megajoule laser beam. If you’re really looking from cradle to grave, it’s 400 megajoules in, and 3.15 megajoules out, which is really pretty far from an energy-producing juggernaut. That doesn’t even take into account the fact that the targets themselves take a lot of time and energy and money to produce.

If you’re not getting more energy out net than energy in, if you consume more energy in building the targets and getting the laser up than the excess that you get, it’s an energy consumer rather than an energy producer.

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How has this fusion quest been going on so long if it’s only just reached this very modest “breakthrough”?

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In the beginning, scientists underestimated how difficult the task was. It seemed like every time they came up with a scheme, nature figured out some way of wriggling out of the constraints they tried to put on it. Through the 1950s, I think, it’s just a lack of knowledge. They didn’t know that this was so difficult.

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But by the time we were in the 1960s and 1970s, I think, there was a recognition that this was going to be a very, very difficult technical achievement. We thought that if we were clever enough to throw enough money in it, enough magnetic power or laser power at the problem, then we would finally be able to brute force it. But it has been evasive.

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With laser fusion in particular, I think one of the things that’s interesting about the NIF is that it was really not designed as an energy project. I don’t think, in their heart of hearts, if you really press the NIF scientists, that they would say the NIF is for proving that we can produce fusion energy. This is really a weapons project. But also, I think there was quite a bit of arrogance in believing that we could overcome these problems nature threw at us just by our sheer power.

If NIF was not meant to look at nuclear tech in an energy-centric manner, I’m curious why you think the Department of Energy is so eager to seize on this announcement.

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Well, it is great PR. Whenever people talk about NIF, they always talk about energy, even though it’s not an energy project, really, so they’re going to milk it for all it’s worth.

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I will say, the numbers from NIF significantly raise my hopes that they’ll get into a testing situation of higher energy yields, as long as they’re able to get these results consistently and on a predictable basis. Still, the overall energy implications here are overhyped, which doesn’t surprise me.

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But they are doing an energy-related project with this fusion experiment, right?

If you look at the energy, assuming you get a 100 percent gain, you get 4 megajoules out for 2 megajoules in. Say you do this once a day. That’s the equivalent of burning a small piece of kindling, roughly. That’s not a power plant. You have to do this at 50–60 hertz thousands of times a day, dozens of times a second, to really have a power plant, which basically means you can’t use this technology. It’s just so far off. You have to move to a different technology sector entirely. Most likely, if there’s going to be a future for fusion, it’s going to be magnetic confinement fusion rather than inertial confinement fusion, which the NIF employs.

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If not the NIF, are there any other laboratories, research facilities, or even private actors who, in your view, are working toward a more promising fusion experiment?

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If I had to choose one right now, I would choose Commonwealth Fusion Systems, which is based in Cambridge, because they are really using traditional designs backed by improved magnets. Their technology is really improving superconductor magnets. Do I think that they’re going to achieve fusion? No, I actually think there are some technical challenges that are going to crop up, but I think that even if they fail, they’re going to fail in a way that actually has some valid uses. They have made some pretty damn good magnets, and making stronger, more efficient magnets is a great use case. So of the ventures out there, that’s the one I’m least scornful of.

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How do the fusion processes compare with nuclear fission, which is a viable and working clean energy source right now?

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Fusion is comparable to fission when you’re looking at disadvantages, and it does have advantages over fission in that the waste it would produce is not as difficult to handle. When you have a fission plant, you are dealing with the case of heavy elements, and you’re winding up with all sorts of waste that’s very, very radioactive and hard to dispose. With fusion, the waste is higher in volume but less horribly radioactive; it’s something that you can deal with more easily. However, some of the designs for fusion plants, once they get off the ground, will have their own special dangers. Most people are talking about breeding tritium by using neutrons from a fusion reactor, in which case there’s the possibility of some problem that leaks radiation to the air or causes some sort of containment breach that is every bit as damaging as a meltdown.

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One can say generally that fusion energy is probably, on some level, cleaner and safer than fission. On the other hand, fission is viable. Fusion is not.

Do you personally think it is even worth sinking more time and money into fusion?

As you have lots and lots of venture capital flowing in, the question becomes how exactly is all this money spent advancing us toward a concrete goal of mitigating climate change, which I think has to be the goal at this point. If you’re spending money in the energy sector, I think it really should, at least on some level, address that pretty directly. NIF is just not on that pathway. And one can argue that we should spend more government money on fusion, but is fusion above all the other things the government could do—improving the efficiency of our grid system, helping improve energy storage? Is fusion the best bang for your buck? I would tend to argue no, but I’m definitely not in the majority.

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Do you foresee any sort of fusion project that could even work on a micro scale instead of as a scalable energy producer?

Do I think it’s possible that we achieve some sort of engineering advance where we genuinely get more energy out than in? Yeah, I do think it’s possible. I’m not hopeful that it will happen anytime in the next decade or two, but it’s definitely possible. I think that the chances, though, of converting that into energy on the grid, much less energy on the grid that is economically competitive with other forms of energy, is slim to none in the next few decades or even the next half-century, I would say.

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We’ve spent a lot of time and a lot of effort, and no one has gotten to square one, where you can say, “OK, make the energy and make me a cup of tea.” I just don’t think that we can say this is the path forward until someone has a working prototype. Am I going to spend my time and money waiting for this as opposed to working on things which are more practical and more immediate? I would say no.

And when it comes to mitigating climate change, we don’t have that much time.

That’s exactly it. I think this whole thing is a bit of a distraction. We’re running out of time. Even if it’s 20 to 30 years away, as great as that will be, it may be too late to avert much of the damage that’s going to come.

Future Tense is a partnership of Slate, New America, and Arizona State University that examines emerging technologies, public policy, and society.

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