Short Wave - A Step Closer To Nuclear Fusion Energy

Episode Date: December 15, 2022

On Dec. 5 at 1 o'clock in the morning local time, researchers at the Lawrence Livermore National Laboratory in California used lasers to zap a tiny pellet of hydrogen fuel. The lasers hit their target with 2.05 megajoules of energy, and the pellet released roughly 3.15 megajoules. It's a major milestone, and one that the field of fusion science has struggled to reach for more than half a century: producing a fusion reaction that generates more energy than it consumes. While progress, the technology is still a ways off from its promise to produce energy without creating greenhouse gases. Today on the show, Regina G. Barber brings us two NPR stories that explain what this experiment showed and what else needs to happen to make fusion a practical energy source.See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Hey folks, Regina Barbara here. You may have heard about a nuclear fusion experiment in the news this week. It's a long-standing holy grail of clean energy. I've been hearing about the promise of fusion energy since I was studying physics and undergrad. And this week, there was an exciting development in this research, while there's still a long way to go for practical applications. Today, we're going to fuse two pieces of excellent coverage from NPR.

First, science correspondent Jeff Brumfield shares his reporting about this breakthrough. Then we're going to hear a conversation NPR's Rob Schmitz had with Dr. Dennis White at MIT about what the technology promises for the long term and some of the barriers that still must be overcome. Today on the show, replicating what happens in the course of stars. I'm Regina Barber and you're listening to Shortwave, the Daily Science podcast from NPR. This week, scientists announced a breakthrough in the field. of nuclear fusion. Fusion is what powers the sun, and scientists have been struggling for decades to harness it on

Earth. Whenever we want the lowdown on nuclear tech, Jeff Brumfield is a guy that we call. Here's a story on the breakthrough and what it could all mean. To give you a sense of just how long this took, listen to President Biden's science advisor, Arati Prabhakar. She remembers working on nuclear fusion in 1978. They got a picture of this. I'm wearing my bell bottoms.

I've got long black hair. show up and I'm a 19-year-old kid and they give me a laser to work on. Prabacher was working at the Department of Energy's Lawrence Livermore National Laboratory, and the job was this. To try and use that laser to squish lightweight atoms of hydrogen together until they fused. It's a process known as nuclear fusion, and it can generate enormous amounts of power with no greenhouse gases.

She worked on it for the summer, and then she left. I went off and didn't do anything more about fusion, but the people I worked with and their successors kept going. And today, decades later, they announced they'd finally done it. The breakthrough came at Livermore's $3.5 billion national ignition facility. Mark Herman is the scientist in charge. He says there's been lots of setbacks and disappointments along the way, but the team never gave up. Ultimately, that determination and grit is really what enabled this exciting success.

Last week, researchers pointed 192 laser beams at a day. tiny diamond sphere the size of a peppercorn. Inside was hydrogen fuel. The lasers went zap. The peppercorn imploded, and the fuel ignited in a fusion burn that released more energy than the lasers put in. They measure energy in something called megajoules, and this fusion made about 3.15 megachules, which sounds cool, but it's not exactly that simple, because lasers actually need a lot of juice from the electricity grid, to work. The laser pulled more than 300 megajoules off the grid, and then the fusion energy came out was, again, about 3 megajoules. In other words, the facility still used way more power overall than it produced. Ryan McBride is a nuclear engineer at the University of Michigan,

who wasn't involved in this breakthrough. He says today's milestone is important. It is a big scientific step. But he says there are several more obstacles to making laser fusion work, To generate steady power would require lasers to zap multiple pellets every second. So it's like brr, you know, that's a lot of pulsing. There's a debris field left as these things are blasted, and you'd have to, like, clear that debris, and then inject another one, have all the lasers hit it. Day after day for months and years, McBride says he doubts laser fusion could produce electrical power anytime soon. It's many decades, as far as I can see.

Meanwhile, the U.S. is seeking to cut its greenhouse gas emissions in half by 2030, a target that looks to be too close for fusion to help. Jeff Brumfield, NPR News. For the second part of this episode, Dr. Dennis White talks to NPR about what this advancement in nuclear fusion could mean for the long term. He talked to NPR's Rob Schmidt just before the announcement. And he started with a quick fusion primer. In fusion, what you're doing is, is literally fusing or pushing together these hydrogen atoms. They turn into helium.

This is what happens in our sun as well too. And when that happens, that can release large amounts of net energy. So what we've been, the achievement of this, which sounds a little bit like science fiction, that you have to achieve extremely high temperatures, like over 50 million degrees, has alluded us about making net energy out of any single, sort of event of this. So if confirmed this morning by the Secretary of Energy, this is indeed a breakthrough. Later this morning, we expect to hear scientists say that they've achieved ignition. What does that mean? Right. So the definition varies slightly between the different

ways that you approach fusion. But the definition that was provided by the National Academies was that for this particular approach to fusion, which uses lasers, that when the amount of fusion energy exceeded the input laser energy, then that was the definition of ignition. There's various other definitions which matter for making it economically viable. And as I understand it, they're generating no electricity, and they are using vastly more electricity than they get out in fusion, but the lasers need a lot of electricity, right?

So this experiment still took energy off the grid? That's correct. I mean, to be clear, they were not even attest. attempting to make electricity out of it. And in fact, this is one of the other aspects that needs to improve, is that you need to get fairly high levels of gain to make this a viable energy source, you know, to be a practical power plant. But getting over the threshold scientifically of seeing net energy is a major accomplishment

because you see for the first time sort of the physical conditions of which will be required for a power plant as we extrapolate. forward. Dr. White, given what we know now, how long do you estimate it'll take for scientists to be able to replicate this discovery on a broader scale so that societies can actually use this type of energy and what steps will we need to take to do that? Right. Well, the exciting thing is that this has been pursued, you know, by science, scientists around the world, including in the United States, obviously, for many decades. And we've made important progress scientifically towards this. But what's changed in the context of what we think we anticipate with this announcement is that indeed

the advent of a private sector in fusion also indicates about both the push and the you know because of climate change and the and the pull that's coming from the commercial sector about getting to the point where we can actually put this on the grid and there is a push to try to do this within the next decade it is difficult the technology is difficult but these are these kinds of advances that provide hope to us that, in fact, we're on the right path. Dennis White is the director of the Plasma Science and Fusion Center at MIT. Dennis, thank you. Thanks for listening to Art Wavers.

This episode was edited by Omina Khan, Ali Schweitzer, Gabriel Spitzer, and Jaselle Grayson. It was produced by Jazeel, our senior supervising editor. Brendan Crump is our podcast coordinator. Beth Donovan is our programming senior director, and Anya Grunman is our senior vice president of programming. I'm Regina Barber. Thanks as always for listening to shortwave, the Daily Science Podcast from NPR.