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Stuff You Should Know

Can Nuclear Fusion Reactors Save The World?

19 Jun 2026

Transcription

Transcript generated automatically by AI and may contain errors.

Chapter 1: What is the main topic discussed in this episode?

0.031 - 3.555 Bobby Bones

This is an iHeart Podcast. Guaranteed human.

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4.517 - 30.367 Hoda Kotb

Joy is essential and it's also elusive. But now, there's a new and exciting way to start your journey toward a more joyful existence. Joy 101. It's a new podcast hosted by me, Hoda Kotb. If you're craving inspiration to maximize your joy, tune into these candid, uplifting, and moving on-air chats. Listen to Joy 101 on the iHeartRadio app, Apple Podcasts, or wherever you get your podcasts.

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30.688 - 34.411 Hoda Kotb

Joy 101 with Hoda Kotb is presented by CVS.

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35.833 - 42.519 Leonard Fournette

Every family has its secrets. But what happens when you discover that your dad has been living a double life?

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43.4 - 49.085 Albert Breer

That is not the look of an innocent man. Is everyone lying to me about who they are?

50.186 - 63.096 Leonard Fournette

I felt such desperation. I felt it was what I had to do. Listen to Deep Cover, The Family Man on the iHeartRadio app, Apple Podcasts, or wherever you get your podcasts.

64.949 - 83.727 Bobby Bones

June is Black Music Month, and on the Drink Champs podcast, we're speaking with the hottest names in the culture, like Swae Lee. Do you realize how legendary you are? I appreciate that. I be seeing it, but I'm like, man, I still got, like, so much more to do. Like, Prince, he dropped, like, 30 albums. We dropped, like, five right now. Like, that's the rate we gotta be going.

83.887 - 90.754 Bobby Bones

Yep, that's a good attitude. No matter the era, Drink Champs brings you the biggest names and the most unfiltered conversations.

90.734 - 110.765 Josh Clark

Listen to Drink Champs from the Black Effect Podcast Network on the iHeartRadio app, Apple Podcasts, or wherever you get your podcasts. Hey everybody, I'm back. I first heard about ITER, which is the nuclear fusion reactor being built in Europe, from a New Yorker article called Star in a Bottle by Rafi Kachadourian.

Chapter 2: What is nuclear fusion and why is it important?

344.703 - 379.429 Josh Clark

And it won't be starting to produce anything until the 2040s at the earliest. So what's the point? I'll tell you the point. If we can figure out nuclear fusion, Chuck, the world's, literally the world's energy problems will be solved for millennia. If we can just figure this out, we will have almost no radioactivity nuclear option, almost limitless fuel supply, Yeah. Totally green.

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379.59 - 380.01 Tegan Taylor

Yeah.

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380.03 - 399.145 Josh Clark

Clean. No pollution, no greenhouse emissions. Right. And with plenty of energy to spare. Yeah. Using the already extant infrastructure we have to supply power. Like you don't have to completely rebuild everything. You can just to the electrical cables outside. Yeah. It'll be the exact same thing.

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399.125 - 406.913 Josh Clark

Yeah, you can just go to a nuclear fission reactor and press the button that says fusion and it'll all of a sudden join atoms instead of split them. Exactly.

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406.933 - 407.553 Tegan Taylor

It's that easy.

407.673 - 424.71 Josh Clark

That's what the difference is. With fission, you're splitting atoms and you're gaining energy from that. With fusion, you're smacking them together and you're gaining even more energy because you're exploiting a different fundamental force. Yeah, and that, I was being coy. Clearly, there is no button because we would have pushed it a long time ago.

424.792 - 442.362 Josh Clark

And when I say no pollution and no greenhouse emissions before the pedantic among you write in, we know that just even shipping something from here to there causes pollution and greenhouse emissions. But we're talking about the output of the reactor itself is very green.

442.342 - 459.608 Josh Clark

So if you want to know all about ITER, well, we're going to talk about it here or there because you just can't talk about nuclear fusion reactors and not mention ITER. But if you want to know a lot about ITER, there is a really great article called A Star in a Bottle, and it's by a person named Rafi Kachadourin.

Chapter 3: How does ITER aim to create nuclear fusion?

459.588 - 480.161 Josh Clark

or durian, and it was written in the New Yorker not too long ago. And, man, it is every detail you want to know about the ITER project written really well. And it's long, but it's totally worth the read. Yeah, it's all over the news lately, and for good reason. You said a lot of energy. I have a stat. I'm going to throw back to the old days here.

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481.644 - 509.668 Josh Clark

Per kilogram of fuel, if we're talking fusion and fission. Lay it on me. Fusion produces four times more energy than fission. I saw seven. It's probably one of those things where it's like five to 10 or something. I found four times. And 10 million times more than coal. 10 million times the energy as coal. And that's with equal fuel per kilogram of fuel. It's just, I mean, it is the future.

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510.028 - 533.093 Josh Clark

Yeah, and you can say, well, that's great because we want 18 million times the amount of power that coal provides. You can say, whoa there, buddy. You can also bring it backwards because you can supply an awful lot of power then with a lot less fuel. Yeah. the advantages of nuclear fusion are mind-boggling. Sure, and very few downsides, which we'll get to, of course.

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533.253 - 555.163 Josh Clark

Yeah, I mean, really genuinely, it's not just like some, here's all the great stuff about it, and just don't pay attention to all these really horrible aspects. Yeah. there really aren't too many downsides. The downside is we are at this moment incapable of successfully creating a commercially viable nuclear fusion reactor.

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556.024 - 579.971 Josh Clark

But we've got an understanding of what the challenges are ahead of us thanks to the last 50 or so years of really, really, really smart physicists working on the problem of nuclear fusion. And the great inspiration for nuclear fusion is the sun. The sun and all stars like it are enormous, immense nuclear fusion reactors.

580.672 - 606.215 Josh Clark

So if you are building a nuclear fusion reactor here on Earth, you're essentially creating a star. And that is a very difficult thing to do, it turns out. Yeah, the sun creates, I know we talked about the sun in our very famous episode on the sun. The sun creates 620 million metric tons. It fuses 620 million metric tons of hydrogen at its core every second.

606.716 - 632.29 Josh Clark

So every second at the sun's core, it produces enough power to light up New York City for 100 years. New York City? Every second. And that's the sun. And all we want to do is do the same thing on a much smaller scale. I think the guy, there was this kid who built one in his garage, and he said he wanted to, I saw this TED talk, he wanted to create a star in a box, is what he called it.

632.388 - 641.198 Josh Clark

Yeah, I've seen it, like this New Yorker called it a star in a bottle. Yeah, this kid's name is Taylor Wilson and he's a nuclear physicist and he's like 16.

641.518 - 643.32 Tegan Taylor

Wow, he's like Stugie Houser.

Chapter 4: What challenges does nuclear fusion face today?

741.104 - 762.316 Josh Clark

Yeah. But I didn't see that they've actually done it. Yeah, 10 megawatts now, and ITER is going to produce 500 megawatts once it's fully operational. Right. So the next challenge then is this. If we're already getting a net energy gain out of it, then that means that the net energy gain is not sustainable.

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762.476 - 781.976 Josh Clark

Like you said, you want to keep the thing going so you don't have to keep starting from scratch to power it up. You want it to basically be self-sustaining so you just have to add a little more fuel to it. That's the dream. So let's talk about the history of fusion reactors, Chuck. Yeah, it kind of goes back to this guy named Lyman Spitzer.

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782.736 - 798.971 Josh Clark

He's a 36-year-old Princeton astrophysicist, and this was in the 1950s. And he was recruited to work on the H-bomb and went out and got a copy of a paper that was released from Germany, I think, right?

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799.351 - 800.952 Tegan Taylor

No, Argentina.

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801.232 - 823.514 Josh Clark

Oh, Argentina? Yeah. Yeah, they announced that they had successfully built a fusion reactor. Right. So he gets this paper, goes on a ski trip, starts thinking about how he can do this, takes a little break from his job building the H-bomb, and figures out, you know, I think it's possible if we can harness this plasma.

824.555 - 838.211 Josh Clark

I guess we should just go ahead and define what plasma is since we keep saying it. Well, there's the normal three energy states that we're familiar with. Water, solid, and gas. Liquid, solid, and gas, right? Right. There's a fourth one. It's plasma.

838.552 - 858.945 Josh Clark

And plasma is basically like an energetic gas where the temperatures are so high that whatever atoms you put into it, the electrons are stripped off and allowed to move around freely. Right. Basically, the surface of the sun is plasma. That's what plasma is. It's a gas. It's a roiling gas that's really hard to control and is really unpredictable.

858.965 - 880.004 Josh Clark

Which is when you see the sun like that rippling, wavy-looking thing. That's plasma. Right, and the reason the sun manages to stay together is because it is enormously massive and has a ton of gravity at its core. Yeah, we don't have that advantage here on Earth. We don't, so we try to make up for that by increasing the temperature. That's right, and he was onto it way back then in the 1950s.

880.104 - 904.901 Josh Clark

If we can just harness this, if we can just get it hot enough, And he created a tabletop device called the Stellarator. And it was in a figure eight position. It was a pipe and a figure eight. Yeah. And this would keep things from banging into walls, theoretically. Yeah. And he was on to something because, well, we'll get to Lockheed later, but they're using a similar device now, a figure eight.

Chapter 5: How does magnetic confinement work in fusion reactors?

915.258 - 929.762 Josh Clark

So the reason that they found out that a donut shape worked was because in the, I think the late 50s, the U.S. had run up against the wall. They were saying like, okay, we've got this, but we can't control the plasma anymore.

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929.742 - 951.702 Josh Clark

because think about it, what you're trying to do is create a star inside something, but it can't touch any of the vessel that it's in, or else it'll just completely erupt it, right? Yeah, they compared it to holding jelly in rubber bands. Right. It was just like you can't, they couldn't figure out how to control the plasma. So when the U.S.

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951.742 - 974.548 Josh Clark

ran up against this wall, they said, hey, rest of the world, we're gonna declassify what Lyman Spitzer has been doing. Help us out. And we'll share if you guys share, and it turns out that the Russians had already come up against this problem and licked it. They figured out that if you put the thing in what's called a toroidal shape, a donut shape,

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974.528 - 1001.295 Josh Clark

Using electromagnets, you can tame the plasma, essentially. And the donut shape itself was pretty ingenious, but the real stroke of genius was by running electromagnets in rings around the donut. So it's like you have a donut and you put a bunch of earrings around it, right? And those are electromagnets, so you're creating an electromagnetic force field which contains the plasma.

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1001.275 - 1024.363 Josh Clark

But then you also put an electromagnetic force field in the middle of the plasma. So not only does it heat it up to the temperatures you want, it also stabilizes it further. So the Russians had invented what they call the Takamak, which is this donut-shaped nuclear fusion reactor that basically became the standard for the next 50 years or so.

1024.343 - 1029.392 Josh Clark

Yeah, you basically could achieve a really dense, super hot plasma.

Chapter 6: What is inertial confinement and how does it differ?

1029.953 - 1044.377 Josh Clark

And we'll get into temperatures and stuff in a bit. But since we can't create that kind of pressure that they have in the sun due to their gravity, their gravity, the sun's gravity, you know, the sun and all those people. Yeah. Like you said, we had to make up for it here on Earth with temperatures.

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1044.357 - 1066.961 Josh Clark

Right, because apparently if you are in the middle of a nuclear reactor, a nuclear fusion reactor, you're going to find that the temperatures inside are about six times hotter than the core of the sun. Not even the surface of the sun, the core of the sun. And the reason why it has to be so much hotter is because, like you said, we can't replicate that density.

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1067.362 - 1082.565 Josh Clark

We can get to those temperatures that we need, but we can't get to that density, so we have to make up for it. So we'll talk about kind of the physics of what's going on here and why you have to have high temperatures and what we're making up for with density and everything right after this.

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1084.452 - 1098.297 Hoda Kotb

Hey, I'm Hoda Kotb, host of the podcast Joy 101 with Hoda Kotb. Together, we're going to have meaningful conversations with the world's most fascinating people, like when actress Olivia Munn shared how she overcame fierce health challenges.

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I've gone through breast cancer and then helped my mother through breast cancer, and that was more difficult. There's a lot of people who understand postpartum depression. I was not prepared for postpartum anxiety.

1107.554 - 1114.543 Hoda Kotb

Listen to Joy 101 with Hoda Kotb on the iHeart Radio app, Apple Podcasts, or wherever you get your podcasts.

1115.671 - 1126.307 Albert Breer

Here at the Happiness Lab, we're serving up some hot takes for the summer. Big ideas that just might reshape how you think about your well-being. Like, we've been thinking about the loneliness epidemic all wrong.

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You can be lonely in a marriage. You can be lonely at a party. I don't think loneliness is actually about solitude. Loneliness is about something much bigger.

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Or that we should get rid of small talk altogether.

Chapter 7: What are the potential benefits of nuclear fusion energy?

1162.617 - 1167.784 Albert Breer

For more surprising ideas backed by psychological science, check out our new series, Happiness Hot Takes.

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Listen to The Happiness Lab with me, Dr. Laurie Santos, on the iHeartRadio app, Apple Podcasts, or wherever you get your podcasts.

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1197.387 - 1211.567 Chuck Bryant

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We talk to the people who lived it, unpacking what happened, how they got through it and what came next. And on our off record episodes, we go even deeper into the reporting and answer the questions you can't stop thinking about. New episodes drop every Thursday on the Exactly Right Network and the iHeart Podcast Network.

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Listen to The Knife on the iHeart Radio app, Apple Podcasts or wherever you get your podcasts.

1235.45 - 1254.07 Josh Clark

So, Chuck, we're talking about nuclear fusion, and it's actually surprisingly understandable at its most basic core. Yeah, you're fusing atoms. It's not the hardest thing in the world to wrap your head around. Yeah, so with fission, we're splitting atoms.

Chapter 8: How does cold fusion differ from traditional fusion?

1254.09 - 1278.248 Josh Clark

You're taking an atom and you're splitting its nuclei apart. You're splitting the neutrons and the protons apart from one another, and when you do that, one of the four fundamental forces, electromagnetic force, pushes them away, and you get this burst of energy. With fusion, you're taking nuclei from different atoms, you're taking protons and neutrons, and you're smashing them together,

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1278.228 - 1300.853 Josh Clark

And when you do that, you're unleashing what's called the strong force, which, appropriately enough, is stronger than electromagnetic force, which is why nuclear fusion yields more energy than nuclear fission. Yeah, Einstein himself said, you know, each time you smash these things together, you're going to lose a little bit of mass, and that little bit of mass is a ton of energy, as it turns out.

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1300.933 - 1321.146 Josh Clark

That's right, the famous E equals MC squared. Yeah, and I don't think he realized in 1905, or maybe Einstein did. Einstein probably did. Yeah, Einstein probably did. I would guess he did. So the problem is, even though it is very easy to smash some protons together, there is a tremendous amount of resistance to that smashing together. They don't want to smash together.

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1321.226 - 1340.677 Josh Clark

No, because it's just like if you take a magnet, two magnets, and you put the positive poles toward one another, they repel one another, right? Same thing, that's the same principle on an atomic level too. If you take protons, which are positively charged particles, and try to put them together, they repel one another.

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1341.078 - 1365.992 Josh Clark

And the closer you get them together, the stronger the repellent force is, the electromagnetic force, right? But, if you can get them close enough, The electromagnetic force is overcome by that strong force, the strong nuclear force, and they become bound together. Because the strong force is one of those four fundamental forces of the universe, and that is the force that keeps atoms together.

1366.553 - 1396.921 Josh Clark

And that force is stronger than the force that repels Like charged particles. Yeah, and when you talk about close, they need to be within 1 times 10 to the negative 15 meters of one another in order to fuse. If you'll indulge me. Sure. Are you going to read a bunch of zeros? Yeah. It's .0000000000001 meters apart. Right. That's how close they have to be. That's right.

1397.803 - 1414.642 Josh Clark

To get them to accept one another and to fuse. I think I have a theory that if they they're not fusing because they think they're going to be made into a bomb. And if we told them that we're creating energy, they might be more willing to fuse together. Yeah, because protons are peaceniks. Everybody knows that.

1414.722 - 1414.983 Chuck Bryant

Sure.

1415.625 - 1440.434 Josh Clark

So when they do fuse together, right, when you do cross that threshold and the strong force takes over and overcomes the electromagnetic force, like we said, a tremendous amount of energy is released. and it's released in part in the form of neutrinos, neutrons, right? Which are neutral particles, which suddenly start carrying a tremendous amount of kinetic energy.

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