Podcast: Fusion stumped us for a century. Can it fuel the future?

 

C&EN’s award-winning podcast Inflection Point leans on our 100-year archive to trace headline topics in science today back to their disparate and surprising roots. In each episode, we explore three lesser-known moments in science history that ultimately led us to current-day breakthroughs. With help from expert C&EN reporters, this show examines how discoveries from our past have shaped our present and will change our future. 

In this episode, hosts David Anderson and Gina Vitale take the time machine as far back as it will go to understand the primordial origins of nuclear fusion. They also bring in C&EN reporter Prachi Patel to untangle the current state of fusion technology and predict whether fusion will power our future.

Subscribe to Inflection Point now on Apple Podcasts, Spotify, or wherever you get your podcasts. 

The following is a transcript of the episode. Interviews have been edited for length and clarity.

Gina Vitale: Hey, David?

David Anderson: Gina.

Gina: What’s—

David: Try to keep your voice down a little bit, OK?

Gina: Oh, OK. Sorry. Why are we whispering?

David: Well, we’re in a university lab right now, Cambridge University—

Gina: University lab, OK.

David: —to be specific. And see that guy over there? He’s very, very intense. He’s really trying to focus. I don’t want to get in the way of any of this.

Gina: Right. OK. And who is that guy again?

David: OK. You don’t recognize him?

Gina: David, why would I recognize that guy?

David: That’s Francis William Aston. So there you go.

Gina: OK, I guess that name kind of sounds familiar, but what is he doing right now that requires such focus that we have to talk like this?

David: Well, OK. As you can see, he’s putting the finishing touches on his new invention, the mass spectrograph. You might know it in the current day as the mass spectrometer.

Gina: Whoa, he is literally inventing the mass spec right now?

David: The very thing, yeah.

Gina: And it’s that thing over there? Because that doesn’t really look anything like the mass spec that I’ve used.

David: La-di-da. All right, fine. Well, they have evolved a lot in the last 100 years. He’s building the first one right here in 1919.

Gina: You know, David, as much as I love the mass spec, and I do love the mass spec, the show is supposed to focus on emerging technologies.

David: OK. Well, the topic of the episode today is not the mass spectrometer.

Gina: Oh, OK.

David: The invention of the mass spec is just the first inflection point. You see, using this brand new device, Aston is about to make a discovery that changes the way we think about energy forever.

Gina: Whoa.

David: He’s going to realize that humans might be able to achieve nuclear fusion.

Gina: You’re telling me that inventing the mass spectrometer—

David: Gina, come on.

Gina: Sorry.

David: He looked over here just now.

Gina: Oh, my God, I’m sorry. Ignore us. Inventing the mass spectrometer led us to nuclear fusion?

David: Yes. And that’s not even half of it. We’re going to go back to the beginning of time.

Gina: Beginning of time?

David: We’re going to see how fuel for fusion reactors was first created.

Gina: OK. Well, if we’re doing all that, we should also explain the basics of what fusion is, fusion versus fission—

David: OK.

Gina: —how it’s used for fuel versus for weapons, and where the technology stands today.

David: Oh, and I almost forgot, we have to visit a candy store in 1957 to learn all about lasers.

Gina: And what? So, David, what are you talking about?

David: Are you ready, Gina, to uncover the origins of this futuristic self-sustaining power source?

Gina: I guess I’m ready.

David: Then let’s go back in time.

Gina: This is Inflection Point.

David: Spanning a century of reporting from C&EN, this new podcast traces discoveries from our past—

Gina: —to how they shape our present—

David: —and will change our future.

Gina: I’m Gina Vitale.

David: And I’m David Anderson.

Gina: All right, so, we are here in 1919 England because this man—

David: Francis William Aston.

Gina: —Francis William Aston is inventing the mass spectrograph, which is an early version of the mass spectrometer.

David: You got it.

Gina: And the mass spectrometer, in its own right, is a huge inflection point in the history of chemistry. Scientists today use it all the time. Let’s say you found a substance and you don’t know exactly what it is.

David: This happens all the time. I’m going through my couch cushions, and I find something. I’m like, “What the?”

Gina: Right. So you can put a sample into a mass spec, and it’ll tell you pretty accurately what one molecule of that substance weighs. And since we already know the weights of all the individual elements, you can work backwards to figure out which elements are in your substance and in what amounts. It basically gives chemists a starting point to identify what they’ve made.

David: Right. They’re pretty handy devices and not just for finding out what kind of dust bunny I have under my couch cushions.

Gina: I’m not sure it would work for that.

David: Now that Aston has this machine that gives accurate weights, he takes a closer look at hydrogen and helium. Back then, scientists thought that helium was basically made up of four hydrogen atoms packed closely together. So they figured one helium should weigh about the same as four hydrogens.

Gina: Sure. I guess that makes sense.

David: But with the mass spectrometer, Aston was able to get really precise weights of the elements, really precise. And he showed beyond a doubt that one helium atom weighs less than four hydrogen atoms. Now, what’s going on there?

Gina: All right, let me bring up my trusty periodic table here. So hydrogen has an atomic weight of 1.0078 atomic mass units, or AMU. Helium is 4.0026, so that’s basically 1 and 4.

David: Right. So those numbers that you’re referencing, those are from a mass spectrograph, right? Those are really, really accurate numbers.

Gina: I would assume so.

David: For the atomic weight?

Gina: I can be more exact. I don’t have to round it to 1 and 4.

David: Right.

Gina: OK. Being exact, I’ll multiply the 1.0078, the weight of hydrogen, by 4.

David: Yeah.

Gina: And that gets me 4.0312.

David: Right, it’s different.

Gina: Which is more than the atomic weight of helium by about three-tenths of an AMU. Interesting. So that means if you were to create a helium atom by combining four hydrogen atoms, some small amount of mass would disappear.

David: Well, OK, not disappear. It would transform.

Gina: Sure, sure.

David: And as we know from a little thing called the law of conservation of matter—

Gina: That old chestnut?

David: Well, I was just reading it this morning. Matter is never created or destroyed, only transformed.

Gina: Right. So if the mass of a helium atom is a little less than the [mass of the] four hydrogen building blocks, then a little bit of mass must be getting transformed.

David: Transformed, exactly. So, in this scenario, it would be getting transformed into energy. And as scientists quickly figured out, this reaction of four hydrogen atoms combining to form one helium atom is actually what powers our own sun.

Gina: Wow.

David: Can you believe it?

Gina: So because of the mass spec, we were able to figure out how fusion literally powers our solar system.

David: Exactly. Pretty cool, right? So before we get into the rest of the episode, I have a basic question about fusion versus fission.

Gina: Sure. OK. Let me hear it.

David: So this process that we’ve been talking about is called fusion, right? Because it involves fusing the atoms together, and that would release energy.

Gina: Right. Good linguistic deduction there. Yes.

David: And fission, as far as I understand, is the opposite. That’s splitting atoms apart, right?

Gina: That is also right. Yes.

David: But fission also releases energy, like a nuclear power plant, even though it’s like the exact opposite process as fusion. So, Gina, I mean, fill me in here. Does that make any sense to you?

Gina: Yeah, I get you. It is confusing. Opposite processes, both releasing energy. That’s weird. I get it. But basically, it comes down to size and stability. So fission uses big and heavy elements. Fusion takes advantage of really light elements. We’ve been talking about hydrogen and helium. Those are the two lightest ones we’ve got. So when two really light elements fuse together, the resulting atom is actually more stable. It doesn’t need as much energy to hold itself together as the smaller building blocks did, so it releases the extra.

David: OK. And so, when it comes to fission, like the nuclear power plant example, it’s not like that, it’s something else?

Gina: Well, it’s kind of the same principle but approached from the opposite direction. You see, for fission, we use really heavy atoms like uranium. When we split a big, unwieldy atom like uranium into smaller atoms, the smaller atoms are actually more stable than the bigger ones. So they release the extra energy that they no longer need to hold themselves together. Does that make sense?

David: Yeah. When you fuse together the lightweight atoms—

Gina: The little babies.

David: —the end result is stable.

Gina: More stable, yes.

David: And then when you break apart the big heavy atoms—

Gina: Stronger atoms.

David: —the result is also more stable.

Gina: Yes.

David: And both release energy.

Gina: Right.

David: I would’ve never guessed.

Gina: Right? Kind of cool.

David: Let me ask this. You got the heavy ones on one side; you got the light ones on the other side. And one’s doing fission, and one’s doing fusion. Is there any point in the periodic table where it switches over like, I don’t know, an inflection point, where atoms get too big to release energy from fusion?

Gina: Actually, yes.

David: That’s wild.

Gina: That transition point, or inflection point, if you want to call it, is iron. So if you fuse iron atoms, they don’t release energy.

David: That’s really interesting. I love that.

Gina: It is really neat. Periodic table, cool stuff.

David: OK. So I understand how fusion and fission both release energy. I got that.

Gina: OK, nice.

David: What’s the difference between using them for nice, stable, reliable energy and using them for that other thing?

Gina: The other thing. Yeah, you mean, bombs?

David: Yes, the bombs.

Gina: Yeah, bombs. It’s a good question. So the answer there comes down to some differences between fusion and fission, and whether the process is controlled or uncontrolled. So picture a nuclear power plant. You’re probably thinking of two big smokestacks, right?

David: Right. Homer’s at the helm, he’s saying “D’oh” and whatnot.

Gina: He’s got a donut or something.

David: He’s yelling at Bart.

Gina: Yeah. Those nuclear power plants are powered with controlled fission. So we’re splitting atoms, but we’re really carefully controlling how much energy goes into it. It’s still a chain reaction, but it’s really slow and manageable. Now, with uncontrolled fission, which is used in atomic bombs, that chain reaction is not as carefully controlled. It is basically allowed to keep powering itself more and more until the reaction becomes really powerful and releases a lot of energy really quickly. That’s why the explosions are so big.

David: OK, got it. Eerie.

Gina: Yeah. So that’s fission. But the principle behind controlled fusion is kind of similar. So in controlled fusion, like in a reactor, the energy would be produced and released in reasonable, steady amounts. In uncontrolled fusion, a lot of energy is released in a really short time, which can be devastating. And this is what’s used in the hydrogen bomb. Well, it’s partly what’s used in the hydrogen bomb.

David: Partly? What do you mean?

Gina: Well, hydrogen bombs actually rely on a fission reaction first to set off a fusion reaction.

David: Wow.

Gina: It takes a lot of energy to set off a fusion reaction. That’s part of the reason people are interested in developing fusion as an energy source because it takes such a massive input of energy to even make fusion happen, a fusion reactor wouldn’t be a threat for a big explosion. If something went wrong in a fusion reactor, it would just shut down.

David: I see. So fusion is safer than fission in that way?

Gina: And that’s not the only pro. In the US, we produce about 2,000 metric tons per year of spent fuel from nuclear fission. Now, that’s honestly not that much relative to how much energy it produces. But some of it is really radioactive and needs to be isolated for thousands of years. Meanwhile, fusion doesn’t generate any waste that is highly radioactive or that will stay radioactive for a superlong time. It mainly produces helium.

David: OK. So with fission, the waste product is this terrible, radioactive junk that we can’t get rid of.

Gina: A little bit of that, yeah.

David: And with fusion, it’s helium, like the stuff that we put in balloons. [Deep inhalation, after which voice gets very high pitched] Like a party balloon?

Gina: [Voice is also high pitched] It’s mainly helium, yeah.

David: Wow.

Gina: It’s pretty harmless.

David: OK, Gina, you sold me. Say no more.

Gina: OK.

David: I can kind of read between the tea leaves here a little bit. I can see that you would like me to start on a fusion reactor. I will start on this immediately. I can’t wait.

Gina: Are you saying I want you to build a fusion reactor? Is that—

David: You’ve been talking about how, what a great source of energy it is.

Gina: Sure.

David: And you know, I’ve been wondering what to do with all that space in my garage, so I think I’ll probably get started this afternoon.

Gina: Yeah, David, you know it’s really not that simple to build a fusion reactor.

David: OK. Well, kind of dashing my dreams. Why not?

Gina: Well, it’s actually pretty hard to do fusion. So the nucleus of an atom, or the part in the very middle, is positively charged. And while positives and negatives attract in chemistry, two positives repel each other. So it takes a lot of energy to force atoms to overcome this repulsion and merge with each other.

David: Sure. But atoms are very small.

Gina: They are small.

David: And I’m big and strong. I think, just kind of grab them and smash them together really hard. I just need to find an atom. They are so small, I can hardly even see them.

Gina: Oh, yeah, it’s going to be difficult. Let’s think about the sun here. Gravity is exerting a ton of pressure on the atoms there, which is helping them come together. There’s also a ton of heat providing energy to help them merge.

David: Yeah. Well, I guess the sun is pretty well known for being big and hot, so that does check out.

Gina: And don’t even get me started on the fuel that you would need.

David: The fuel, yeah. I guess it probably wouldn’t be that hard to get some deuterium, but tritium, boy, it’s getting so expensive these days. You know for a single gram, it’s $30,000. Can you believe what, I mean, talk about pain in the pump. It’s ridiculous.

Gina: Wait a second. You know about deuterium and tritium?

David: Yeah, of course. Deuterium and tritium, they’re isotopes of hydrogen, Gina.

Gina: Yeah, OK.

David: As you and I both know, isotopes are the tiny bugs that roll into a ball.

Gina: OK. David, I think you’re referring to isopods, like a pill bug, not isotopes.

David: Well, crabs are also isopods. Not many people think of them like that. They think—

Gina: OK. I am just going to take this one, actually. So isotopes are different versions of the same chemical element. Each isotope of an element has the same atomic number—they have the same number of protons—but they have different amounts of neutrons. So they also have different atomic masses. You following me so far?

David: Yeah. So deuterium and tritium, they are both isotopes of hydrogen.

Gina: Right.

David: What we think of as regular standard hydrogen—

Gina: Good, old hydrogen.

David: —has one proton and no neutrons.

Gina: Right.

David: Deuterium has one proton and one neutron. Tritium has one proton and two neutrons. So together, deuterium and tritium, they are a very common fuel for fusion reactions.

Gina: Right. That’s all true. But this is a very sudden shift into lucidity for you. I’m starting to get a little suspicious.

David: I was confusing isopods for isotopes earlier.

Gina: And now you’re talking intelligently about tritium.

David: Yeah.

Gina: I’m surprised that you know this much about the most common fuels that fusion reactors use. Are you—

David: Sure.

Gina: Is this like a sneaky setup for an inflection point? Are you about to launch into a—

David: Do I do that? Do I often sneakily kind of set up a inflection point?

Gina: Oh, do you do that. Oh boy, come on, David.

David: Kind of jump into it without notice?

Gina: I would say that’s something you do, yes.

David: Yeah. OK. You got me red-handed yet again. All right, Gina, let’s go back to . . .

Gina: What is it?

David: OK, that can’t be right.

Gina: What? What are you looking at?

David: I’m looking at my notes, and this is like this thing from earlier in the intro. I can’t believe this.

Gina: God, these are so hard to read. This handwriting is like a child wrote it—

David: Well, my dad was a doctor, so I inherited a bad handwriting. It looks like we need to go back to—I’m just reading this verbatim here—the beginning of time. We need to go back to the Big Bang.

Gina: The beginning of time.

David: The Big Bang.

Gina: David, you’re saying we need to go back 13.8 billion years ago?

David: Yeah.

Gina: Maybe this could just be like a normal inflection point. Maybe we don’t have to do—

David: You have a spacesuit, right?

Gina: Oh, David.

David: Don’t worry. I’ve got spares. There’s this little locker in the time machine that I keep the space suits in.

Gina: OK. And it’s my size? Because you know how I hate to—I’m just always swimming in those things.

David: Yeah, yeah, yeah. No, I got it tailored special. You will not believe how expensive it was. First of all, you—

Gina: To tailor a space suit?

David: We need to talk about Venmo a little bit. Let’s go back to the Big Bang.

[Inflection point sound effect: digital blips and tape-rewinding whir]

David: David to Gina, over and out. Copy. Do you read me? 10-4.

Gina: Unfortunately, yes.

David: Over and out.

Gina: David, I can hear you over the spacesuit intercom, if that’s what you’re asking.

David: Roger, that. Breaker, breaker.

Gina: OK. So we’re here—

David: Over and out, et cetera.

Gina: Right. We’re floating in nothing because—

David: Copy that.

Gina: —not even space has been created yet. And we’re waiting for the Big Bang to happen. How late is this going to—

[Sound cuts out briefly and then a large ‘Big Bang’ sounds]

Gina: —Whoa. OK. That was pretty cool.

David: Beautiful, right? Kind of awe inspiring.

Gina: Yeah. Yeah, yeah, yeah, yeah, yeah.

David: Makes you think.

Gina: Birth of the universe and all that. It really brings up existential questions for me watching this, such as Why have you dragged me here?

David: I was kind of enjoying the majesty of the known universe.

Gina: That was nice.

David: You would like to know what we’re doing here. You just want to get down to business.

Gina: I kind of would like to get down to brass tacks. Yeah.

David: OK, fair enough. Well, we’re here watching the creation of those hydrogen isotopes that I mentioned, the fuel that powers so many fusion devices. They’re being created right now.

Gina: OK, sure. But isn’t that a little bit cheating? Didn’t we just watch the creation of everything that we’ve ever known?

David: Well, I don’t think it’s cheating, no, because while we did watch the creation of all matter that we know about, we’re really just seeing the basic building blocks. Right now, there are only three elements. All the rest will come later. Most are forged inside stars or created when stars explode. So, you and I would have to wait around a few hundred million years for all this hydrogen, helium, and tiny bit of lithium to coalesce into a star before we can start fiddling around with the rest of the periodic table.

Gina: So after the Big Bang, it takes hundreds of millions of years before a fourth element is made?

David: Yeah.

Gina: Wow.

David: Pretty wild, actually. But don’t forget the hydrogen isotopes. They’re here as well.

Gina: Right, right, right. You mentioned deuterium and tritium are used as fuels in a lot of fusion devices.

David: And we are watching it unfold right in front of us. They’re being created this very moment.

Gina: OK, that’s pretty cool. I guess seeing the Big Bang is sort of a bucket list thing for me as someone who has access to a time machine. So deuterium and tritium are created. So now we have these two isotopes that we can force together for fusion power. What makes them good for fusion reactors?

David: I’m so glad you asked. See, when you smash these two isotopes together, they actually end up creating helium like you mentioned, similar to how smashing four regular hydrogens together would form helium.

Gina: And as we learned earlier, when you create helium from four hydrogen atoms, a tiny bit of mass gets turned into energy. So would smashing the two hydrogen isotopes together to form helium also release energy?

David: Yes. And it would release a lot of energy.

Gina: So why use the isotopes as fuel instead of the regular hydrogen, like the reaction that powers the sun?

David: Right. Why fiddle around with these finicky little isotopes?

Gina: Yeah.

David: With regular hydrogen, it’s really hard to pull off. It’s still pretty hard with the isotopes.

Gina: Sure.

David: But it’s doable by humans at least. We don’t have to go inside of a star.

Gina: Sure. OK. But why use hydrogen isotopes for fusion versus any other element?

David: Right.

Gina: Earlier, we talked about elements lighter than iron being able to fuse, and there’s a lot of those. So why not use any of those?

David: For starters, why not just go for the lightest stuff on the periodic table?

Gina: Sure.

David: This is basically the most practical fusion reaction that you can do on Earth. Compared to the other fusion reactions that you posited, the deuterium-tritium combo releases the most amount of energy at the lowest temperatures. But even the lowest temperature that we’re talking about is still really, really hot. When we’re trying to do a fusion reaction, the temperature we need is 150,000,000 °C.

Gina: That is pretty hot. So why does it need to get so hot?

David: In order for elements to fuse, in order for this process to even begin to take place, they need to turn into a new state of matter entirely.

Gina: I see. So they need to turn into plasma. Is that what you’re saying?

David: Exactly, GV, the plasma. So I’ve been researching this episode, and as soon as I started reading about plasma, I started thinking about lava. Is plasma like lava? Lava is also really hot, and it’s kind of goopy. And when I think of the word plasma, it’s just kind of like a goopy kind of sounding word like plasma.

Gina: Yeah, plasma.

David: It’s got to be goop based.

Gina: Sure. Sound as that logic is—

David: Am I right or am I right?

Gina: —lava is actually not plasma, though the sun is plasma, and it looks a little goopy, I guess.

David: Vindicated once again.

Gina: But plasma is actually a little harder to define than solid, liquid, or gas. And plasma is not always really hot. Depending on what makes up the plasma, it can look or behave differently. Fluorescent lights have plasma. Those torches that welders use have plasma. Lightning is plasma too.

David: Let me get this straight. So the fusion using hydrogen isotopes requires temperatures in the millions of degrees.

Gina: Yes.

David: And this process creates plasma, but you’re telling me somehow there’s also plasma in everyday objects like fluorescent lights?

Gina: Yeah. I think the temperature thing is throwing you off a little bit here. Plasma forms when the atoms in a gas become ionized. That means electrons, which are orbiting around pretty close to the center of an atom, separate and float around independently.

David: Got it.

Gina: This turns the gas into an electrically charged soup where positively charged and negatively charged particles mix freely. Matter doesn’t necessarily have to be at a superhigh temperature to reach a plasma state. We just usually need really high temperatures to make those elements fuse, like in a fusion reactor.

David: OK, Gina, I am starting to put together the pieces of why fusion is so difficult to pull off. I’m starting to add it all up.

Gina: Right. It is really difficult. And even though we had known about fusion since the 1920s, like you pointed out in your first mass spec inflection point, it wasn’t actually until 2022 that we were able to get more energy out of a fusion reactor than we put in for the first time.

David: Twenty twenty-two? So it took a hundred years for this?

Gina: Yeah. The ultimate goal with a fusion reactor is of course to be self-sustaining. We wanted to produce enough energy both to meet all of our needs and also to continuously power itself.

David: Sure.

Gina: In nuclear world, this is a concept called ignition.

David: OK. And until very recently, ignition had just not happened?

Gina: Technically, yes.

David: Wow.

Gina: It wasn’t until 2022 at the National Ignition Facility at Lawrence Livermore National Laboratory in California that scientists put in 2.05 MJ of energy and the device put out 3.15 MJ.

David: OK, Gina. So would you be surprised if I told you that that breakthrough that we just talked about is partially thanks to an enigmatic, chain-smoking inventor who notarized his new invention at a candy store? Would that surprise you?

Gina: Even after all the nonsense you have told me over the past few seasons, David?

David: Nonsense?

Gina: Yes, I have to admit that does still surprise me.

David: OK, Gina. Well, I’m going to decide to not take that personally. Let’s just go back to 1957.

[Inflection point sound effect: digital blips and tape-rewinding whir]

Gina: [Coughing] God, David, you were not kidding about this guy being a chain-smoker. I can hardly see you across this room.

David: Sorry about that. I’ll open a window. OK. Let’s just clear the—

Gina: Please.

David: I’m going to fan the air a little bit. Does that feel good? Is that better?

Gina: It’s starting to clear up.

David: I can still kind of smell it. The smell’s never going away, for sure.

Gina: God, yeah, I’m going to have to wash these clothes 10 times. OK. Where are we again?

David: Yeah, we are here in the Bronx, and we’re in the study of a man named Gordon Gould.

Gina: Gordon Gould. OK. Looks like he is not here. Seems like he kind of left in a hurry.

David: Yeah. Just moments earlier, he dashed right out of here and rushed to the neighborhood candy store.

Gina: Candy emergency. I have been there. I have something of a sweet tooth myself, so I do really sympathize.

David: Yeah, sure. That sounds—

Gina: Actually, can we take a break right now because I—

David: Kind of got candy on the brain, huh?

Gina: Yeah.

David: Well, anyway, back to the matter at hand, Gina.

Gina: OK.

David: This guy did not have a candy emergency. He wasn’t off getting candy, or maybe he was getting candy, but the whole point of this story, back to my inflection point, before it was so unceremoniously derailed.

Gina: OK, sorry about that.

David: The owner of that candy store is a notary public. Gould is over there right now getting some papers of his notarized. In these documents, Gould lays out his designs for something that we need to reach that fusion milestone you mentioned a few moments earlier.

Gina: Right. The first successful ignition experiment in 2022.

David: Yeah.

Gina: So this has to do with that?

David: Right. On those papers that Gould rushed over to the candy store is his concept for harnessing light into a single, concentrated beam. You might know it as a laser.

Gina: Whoa. OK. Well, for some reason I thought the laser had been around before 1957.

David: Yeah.

Gina: OK. So what does the laser have to do with fusion?

David: There are a couple different ways to achieve fusion. The one you mentioned, at the National Ignition Facility, the NIF, uses hundreds of superpowerful, gigantic lasers to create the plasma conditions that our fuel, those precious little isotopes, need to fuse. The lasers at this facility are enormous. They’re bigger than a football field, and all the energy those lasers produce is focused on one tiny little target the size of a peppercorn.

Gina: So, just to make sure that we’re talking about the same thing here, in that tiny little target, that’s where all the fusion that we’re talking about takes place?

David: Yeah. Yeah, that’s exactly how it works. It’s in that little ball that all that hydrogen fuel gets plasmaed by those big lasers.

Gina: Plasmaed, right. OK. I get that the invention of lasers is really important to this kind of fusion device. So what happened to Gould after he went to the candy store to notarize his designs or whatever?

David: Right. For a long time, Gould didn’t get any credit for his invention, actually. I mentioned at the candy store, he notarized his papers. He didn’t patent the idea. He was at the time under the erroneous impression that you needed a working model of something to get a patent for it.

Gina: Oh, man. So someone else came along and patented it on their own?

David: Yeah, exactly right. A year later, in 1958, two scientists working at Bell Labs filed a patent. Though, to their credit, it does seem like they came up with their idea for the laser independently of Gould. And oddly enough, they never even got around to building it. It was in 1960 yet another person comes along and actually ends up making a laser for the first time.

Gina: Wow. What an interesting sequence of events. So that’s really dire for Gould, right? Lasers are used everywhere now, and not just for fusion, obviously. They’re used to scan groceries. They’re in fiber-optic communication. They’re even in quantum computing, which we have an episode on, by the way, so you should check that out.

David: It’s a very good episode. But don’t forget, we also use lasers for our cats so they have a little red dot to chase around.

Gina: That is true. How could I forget that? My point is that it’s a huge market. And if Gould missed out on the patent for lasers, then he’s probably leaving millions of dollars on the table. That’s a real bummer.

David: Yeah, that would be a bummer. But you remember earlier this talk about the candy store? Maybe you blacked out at the mention of candy. You started thinking about the Snickers and et cetera.

Gina: I did get a little bit distracted there, yeah.

David: So what he was doing there, right, was getting his idea notarized, which isn’t totally worthless. So eventually, in 1988, after a lot of court battles, finally, the patent and trademark office ruled that Gould should collect royalties on his invention. That ruling made him a millionaire. And without that trip to the candy store, who knows?

Gina: Wow. Well, good for him. It’s cool that he finally got credit for his invention.

David: Yeah.

Gina: Something you said earlier actually piqued my interest. You mentioned that this reactor, the one that achieved ignition—

David: Right, as you were describing getting more energy out of the reaction than was put in.

Gina: Yeah. You said that that was just one kind of fusion device. Are there fusion reactors that don’t use lasers?

David: Yeah. I mean, maybe they use lasers in different ways, like to make measurements or something, but lasers aren’t strictly the only way to make things fuse.

Prachi Patel: One way is to use magnetic fields. The most common type of reactor design for this is what’s known as a tokamak.

Gina: That’s Prachi Patel. She’s a senior editor at C&EN who covers materials science and energy. You might recognize her from our episode on lithium ion batteries.

Prachi: It’s a donut-shaped device and because of the way the coils and the magnets are shaped, this creates a very intense magnetic field that kind of creates and maintains that plasma that we need for fusion. And I’d say that most big research projects, and certainly most fusion energy start-ups, are using this kind of donut tokamak design for fusion power.

David: Fusion energy start-ups. OK. So we’ve got the fusion energy start-ups. We’ve got the NIF. They already did ignition. Can’t we just say, “All right, job done, let’s all go home”?

Gina: They did do ignition, but we still can’t continuously get more energy out from a fusion reactor than we’re putting in. So that’s the next challenge that we need to overcome.

David: OK. But they’ve been working on it for like 50 years.

Gina: Well, it’s really hard.

Prachi: To achieve that ignition to get that plasma, you need to heat that hydrogen isotope fuel to a crazy high temperature. I think it’s at least 100,000,000 °C is the temperature that it needs to be at. This is the kind of reactions that are happening in stars. So it’s really hard to recreate that process on Earth. Not easy to do. It requires an immense amount of energy, and you need to control and maintain that plasma, which is very unstable. It just wants to fizzle out as soon as it can. You can’t let it touch the walls, the walls would melt or vaporize. You need a very high pressure to control that plasma and keep it dense enough to keep those fusion reactions going.

David: All right. So it’s really hard not only to get the fuel hot enough to turn it into a plasma but also to sustain it and keep it contained. That does sound difficult.

Gina: Yeah, that’s true. But the cool part is the fact that it’s so hard to make and sustain plasma actually makes these reactors pretty safe.

David: Oh, right. Like we were talking about earlier. OK. But come on, we’re trying to do a reaction that’s similar to something going on inside the sun. It’s just so extreme. How could that possibly be safe, for real?

Prachi: You’re trying to fuse nuclei, which inherently don’t want to fuse, and which is why you have to put in this high temperature and high pressure to create that plasma. So that plasma is finicky. It’s very tricky to start. It’s very tricky to maintain. And then fusion also needs its continuous fuel input. What makes that plasma difficult to create is also kind of what makes it easy to fizzle out.

Gina: Basically, the conditions have to be just right for plasma to exist. If anything goes wrong, the plasma loses energy, cools down, and the whole reactor just stops.

David: OK. So no big nuclear meltdown?

Gina: No. There’s no chain reaction that can get uncontrolled like there is with fission.

David: So fusion power doesn’t have a lot of harmful by-products, and it’s really safe.

Gina: Yeah.

David: Really sounds like it would be really, really cool if we actually had fusion power plants that worked at scale.

Gina: Well, we might not be terribly far off.

Prachi: So I would say most experts I have spoken with for the story I wrote for C&EN say it’s not a matter of if but when. They think that the hardest part, the fundamental physics and materials science part, is done. Now it’s a matter of, like we said, optimization, engineering, and all of that will need a lot of continued funding and a lot of support. And what has really changed the fusion conversation recently is all this interest from the private sector. A lot of big tech companies are behind fusion. Private investors have poured in at this point, I think more than $10 billion into fusion start-ups. And there are over 50 fusion energy start-ups around the world. In terms of timeline, I think at least five are planning to switch on their test reactors before 2030.

David: Twenty thirty, that’s very soon.

Gina: Well, that’s kind of the best-case scenario. It might be later, but yeah, it seems like it’s on the horizon.

David: That is amazing. And thank you, Prachi, for explaining all that.

Prachi: All right. Thanks, guys. Thanks, Gina. Thanks, David. It’s great to be on the show again.

David: OK. So back to my fusion reactor.

Gina: Sorry.

David: Of course, you remember?

Gina: What fusion reactor?

David: Gina, the one that I’m building in my garage.

Gina: Oh, brother.

David: My personal fusion reactor.

Gina: Yes, right. About that—

David: I’m pretty serious about this. I’m also serious about safety and PPE [personal protective equipment]. So I’ve got some safety goggles and a lab coat.

Gina: Yeah, safety goggles and a lab coat, wow.

David: Do you think that’s enough? OK, one problem, I can see you’re already kind of looking over my lab coat. Yes, I know it’s a little ridiculous. I ordered a child’s large on accident. That’s on me. I own that. I’m coming forward and saying, “Yes, I have a little lab coat that’s too small.”

Gina: I’m going to say no, David. I don’t think that that’s going to be nearly enough safety equipment, actually.

David: I have gloves as well. I’ve got some snowboarding gloves that I can get in my basement.

Gina: Oh, he has gloves, OK. Oh, snowboarding gloves. Great.

David: So—

Gina: How about this? Why don’t you wait until someone figures out how to do cold fusion? That way you won’t need to be flinging superhot plasma around in your garage.

David: Sure. OK. Well, that’s good, because I got the snowboarding gloves, so cold. Sounds like those would really shine in that environment. What is cold fusion, before I get started on my blueprints here?

Gina: Yeah. Well, it’s this sort of fringe, totally hypothetical idea—

David: Sounds right up my alley.

Gina: —that we could one day do fusion at room temperature.

David: Okay. I could be the enigmatic inventor for a future inflection point.

Gina: You so could.

David: But hold on. We just talked about how it needs to be superhot for elements to fuse. So this doesn’t seem very likely, Gina. I mean, I hate to be a skeptic.

Gina: Yeah.

David: But is it even possible?

Gina: Well, I’ll be honest with you, it doesn’t look very possible, but it’s science. I’m sure somebody will spill a Diet Coke on a piece of metal, and—

David: There we go. See?

Gina: —suddenly, they’ll break the field wide open. You know how these things go.

David: That could be me. Something with the snowboarding gloves, the spilling of the Diet Coke.

Gina: Sure.

David: In 40 years, somebody’s talking about this weirdo inventor in his garage, and it’s me. I’m the weirdo inventor.

Gina: Yeah, I could totally see that for you. But before you start working on all of that, why don’t you tell us what we’re covering in the next episode?

David: Right. OK. Well, next episode, first we will be visiting Paul Revere.

Gina: Paul Revere, the famous—

David: Paul Revere.

Gina: —Revolutionary War guy?

David: Oh. Yeah, I guess that’s how some people know him.

Gina: Some people.

David: I think of Paul Revere as an early adopter of recycling.

Gina: OK. So we’re going to cover recycling?

David: Well, not just recycling, GV, plastics recycling. It’s a thorny, thorny issue. Well, there’s a lot to sort out if you will. There’s a lot—

Gina: Oh, brother, OK. Sure. Plastics recycling is tough to untangle. So we should probably explain why plastics are so tricky to recycle and how much plastic actually gets recycled.

David: Oh, and we will also need to visit the Wyeth House in Pennsylvania.

Gina: No way. Are we going to meet Andrew Wyeth, the famous painter?

David: Famous painter. Oh, you must be referring to Nathaniel Wyeth’s brother, right. I guess he did some paintings or something.

Gina: He has a painting in the MoMA [Museum of Modern Art], David.

David: OK. Well, his brother, Nathaniel, is the one I’m referring to.

Gina: OK.

David: He’s the famous inventor of our modern soda bottle.

Gina: That is incredible. OK. Well, we’ll also explain the future of plastics recycling.

David: Plastics recycling also has some pretty controversial origins. There’s this racist TV ad.

Gina: OK. OK. OK. David, you know what? Let’s save some of it for the episode. Maybe you and I should workshop some of this stuff outside the pod.

David: OK. Whatever you say, GV. We can work on it while we work on, hey, my new fusion reactor.

Gina: The reactor.

David: What do you say? Could you hand me the nail gun over there on the shelf? It’s just right behind you.

Gina: No, absolutely not. Inflection Point is a podcast project from Chemical & Engineering News.

David:Chemical & Engineering News is the official news outlet of the American Chemical Society.

Gina: Music by Kirk Ohnstad, Jeremy Barr, David Anderson, and Shutterstock.

David: Written, produced, and hosted by Gina Vitale and David Anderson.

Gina: Our audio producer is Jeremy Barr.

David: Our fact-checker is Michelle Boucher.

Gina: Email us at [email protected].

David: By the way, we have a quick correction for one of our earlier episodes. In our episode on retinol, season 3, episode 1, we were talking about a new birth control candidate for men, and we accidentally called it YTC529. The correct name is YCT529. The audio in that episode has now been corrected. Thanks for listening.