The State of Fusion Energy w/ Gerrit Bruhaug

0:00Decouple Host: We would build a bigger facility and a bigger facility would get more gain. So you would get a lot more fusion for the same amount of laser you put in. You'd make it frighteningly bigger, to be honest. We would be setting off the equivalent of hundreds of kilos of TNT worth of explosion every time this thing fires.

0:20Gerrit Bruhaug: A warm welcome back to Decouple. And a very warm welcome back to Gerrit Bruhaug. Garrett is someone who I feel is like a close personal friend. We've never met in person. It's not unusual for my network, for better or for worse. Hopefully we'll remedy that one day. Garrett has actually been on the podcast twice before. I would say he is our resident fusion expert. I do not spend perhaps enough time delving into that topic. We last spoke after the break-even event or the ignition event, I should say, at the National Ignition Facility. There was a lot of hype at that time. Garrett, you've worn a few different hats.

1:00Gerrit Bruhaug: So in terms of your intro, you were at Rochester shooting big lasers. You've been somewhere else, maybe a little more mysterious recently, shooting big lasers. I don't want to just say that all you do is shoot big lasers. But yeah, fill in that background.

1:13Decouple Host: Yeah, sure. Happy to be back. Hopefully we can remedy the in-person meeting sometime, go ride some horses or do some hunting or something like that. But yeah, last time we talked, I was still a graduate student at the University of Rochester. and now I am Dr. Garrett Bruhag, although it really weirds me out when I hear that. Whenever I get introduced that way, I wonder who that guy is. I was at Los Alamos National Laboratory for the past couple of years. I was a postdoctoral named fellow and then a staff scientist working on all sorts of things, big lasers, but big particle accelerators, a lot of stuff for national security.

1:49Decouple Host: And then recently just made the jump to the private fusion industry, which was if you'd asked me even six months ago, I would have said you're insane that I would have done that. But had an offer. I couldn't refuse to go work on a bit of a dream job with some of my best friends in a place that I really love to live in. So now I'm up here in Denver.

2:10Gerrit Bruhaug: Awesome. Well, I'm happy for you, man. And yeah, your allusion to horseback riding and hunting. I do think that's an interesting part of your resume. And somewhere I feel a deep bond with you as a former horse wrangler and hunting guide. You were like a Montana cowboy for a little while. Is that correct?

2:27Decouple Host: A brief part of my life, yeah. I did grow up in Montana. So, you know, everyone out there is a little more cowboy than the rest of the country.

2:36Gerrit Bruhaug: Well, without further ado, let's get to the matter at hand. So I'm like not infrequently asked about my opinions on Fusion. And like most of my opinions, they're a little bit uneducated. I'm trying to lean into that a little more. I tend to over-prepare for the podcast. but in this episode, really bring in my beginner's mind to the front of the table. And I usually duck those questions and just, you know, freely admit, I don't know much about fusion. My gut is, you know, that it's a lot more complicated than fission. You know, one of the things I'll often offer is, you know, from, you know, the kind of lab bench experiments of Lise Meitner and Otto Hahn, you know, figuring out that what they'd done on that table was fission through, I guess, bombarding a heavy unstable nuclei with some neutrons to, let's say, shipping port nuclear power plant.

3:20Gerrit Bruhaug: I'm not sure if it was commercially super successful, but commercial nuclear power was like 18 years, even shorter for the Nautilus submarine, obviously. And I actually learned in my prep today that Oliphant et al. sort of, I think, produced the first human-made fusion, I think in 34. And we are maybe getting closer to commercial fusion power. That's one of my points, but we're going to delve a lot deeper into the topic at hand today. I think you're an excellent science communicator for this podcast audience, which is, you know, a bunch of nukeners and fission heads, if that's a term. Trying to just, I guess, dive into some of the similarities and differences between fission and fusion.

4:04Decouple Host: I think starting with the history is pretty fun because I learned relatively recently that the story is even more complicated. So fusion was found before fission, which sounds crazy, but fission was a big surprise. People kind of thought fusion had to be a thing. They were starting to wonder what's powering the stars. There's only so many answers. And fission's like a cheat code for the universe, but fusion makes a lot of sense when you start to do even very basic nuclear physics. I was joking with a friend of mine that I could probably explain fusion to someone a couple hundred years ago because it's just really hard fire.

4:36Decouple Host: It's Like, what if fire had like an extra hard mode? Whereas fission sounds like witchcraft. You arrange the magic rocks in the right way and all of a sudden you get energy. Like, come on, dude. In 34 is when like the official reaction was found. It was actually Ernest Lawrence, you know, Nobel Prize winning fame and Lawrence Livermore National Laboratory, who found fusion first with his cyclotron. He was shooting deuterium atoms and he was hitting a solid target. and the beam from the cyclotron was building up deuterium into the target. And then he was eventually getting neutrons out. And he was convinced he was doing a different kind of reaction.

5:13Decouple Host: He thought he was like knocking neutrons off, which is a thing that does happen. And he was touring the world. And I believe he was in the UK when he was explaining, is it the UK or Italy? One of the two. And he was explaining this experiment. And all those smart Brits said, no, man, you are way off. You did fusion. You did a way bigger thing. and lawrence was so convinced that they were wrong and then he refused to um cede the point so they went and did a better version of the experiment published it won the nobel and showed fusion and that's all the fonts in rutherford yep yeah okay and it's funny because lawrence could have gotten a second nobel by just having a little bit of um humility and uh admitting that maybe he

5:54Gerrit Bruhaug: didn't know everything okay that's that's like so that's like 30s early 30s yeah early 30s and so

6:00Decouple Host: we know about this. And then people are thinking like, okay, someday maybe we're starting to understand these conditions, but they're insane. And then you get fission, you get the bomb, and famously Teller starts immediately going, hey, I think using the bomb, we could get a fusion reaction. And there was the whole concern about igniting the atmosphere and all this sort of crazy stuff that they had to run through and prove wasn't going to happen because there's a lot of fusion reactions out there. There's not just the ones that we like to use in the labs. There's all these crazy ones in stars where like oxygen and nitrogen can undergo fusion and things like that that are, you know, would be a concern in an oxygen-nitrogen atmosphere.

6:39Decouple Host: For fission, we go from, what is it, 38 to 45. We have reactors and weapons and everything is like moving forward. We have commercial power into the 50s. Fusion, we don't get to that point, even just the weapons point, the unfriendly version of it until well into the 50s. and you know we're still uh working away on the power plant side of it but um the big thing was to actually get a self-sustaining chain reaction and this is this is like the really important key point that a lot of people miss also with the niff um anyone can make which is the national

7:14Gerrit Bruhaug: ignition facility yeah the national ignition facility sorry hold me on those acronyms

7:18Decouple Host: will be so anyone can make fusion in their garage with high voltage um really it's pretty easy oh yeah, there's these little fusers. There's like a 12-year-old who I think has the world record. You draw something like 40 ,000 volts in a vacuum and you get some deuterium gas and you puff it in there and it accelerates and it hits. And that's beam-beam or beam-target fusion. So that's what Rutherford, that's what Lawrence, that's what everyone was doing. And this kind of fusion is actually a really common way to get neutrons. There's a lot of little portable neutron generators. So the classic way to do this is radioactive decay.

7:51Decouple Host: For a lot of reasons, people don't always want to have a big chunk of, say, like, Californium around. Neutron generators are just little tiny fusion reaction devices. And I mean, like, this big. They can be super small. You fire some high voltage, you get some neutrons. Oil industry uses them. There's all sorts of non-destructive analysis to see, like, if bridges are safe, things like that. You can use them to start nuclear reactors because, you know, for a fission reactor, you have to have neutrons to chain react it. So, you know, That's a real common trick, but that can't scale to net energy because it can't self-heat.

8:25Decouple Host: You're putting in a bunch of energy to accelerate things up, to get the energy into those ions. And then most of what they do is scatter. It's like a classic plasma physics graduate student problem of like, show me why we can't just build a particle accelerator and why that can't be a fusion reactor. And it's because you get a hundred times more scatters than fusion events in the best case scenario. Like you ignore, you do your spherical cow, you ignore all of like thermodynamics and everything, and you still just mostly bounce off. So, you know, that would be a neat trick, but it would be utterly useless for energy or a weapon or anything like that.

9:03Decouple Host: To really make the magic happen, you have to make it do a sustaining chain reaction, which was, of course, the big thing that Fermi did with fission, right? That was why Chicago Pile was such a big deal. It's not just that you could split an atom, it's that you could split an atom and make an atom split more atoms. So to get to that point with fusion is much harder because the conditions are crazy. Fission happens at room temp. It doesn't care about temperature. It doesn't care about pressure. For fusion, we have these confinement conditions called the Lawson criterion. And it's some combination of time, temperature, and pressure that you have to meet to get the plasma to self-heat.

9:40Decouple Host: Because also as you're getting, this is the real crappy part, is you're getting the plasma hot and you're starting to get these reactions. You get them hot enough so the ions can actually run into each other and cause fusion. You lose the heat. You lose the heat. Yeah. Like you ever gotten a piece of metal hot source to glow for fusion, it glows in x-rays that like thermal loss goes, you know, to the fourth power. So it's, it's really bad. So we, you know, we have to be very, very clever about this. And there's, there's three ways that we know. Well, I'm going to say two ways we know it can work in one way that hopefully somebody will soon show.

10:14Decouple Host: So we know gravitational confinement works because the sun. Right. The sun cheats by being huge. The sun is actually really low power. It's got the power density of a human in terms of like volume. Like it's making as many watts as you are. It's just big. Reacts really slowly.

10:32Gerrit Bruhaug: Massive gravitational, I guess, pressure you mentioned was one of the ingredients. Temperatures are not that hot, but time is forever.

10:38Decouple Host: They're hot to us on Earth and they're cold to people in the fusion world. So when we do fusion experiments, we go like 10x the sun. Easy. Wow. The sun is also cheating in that we were talking about that radiation loss. The sun is so big, it confines its own radiation. Have you ever heard that factoid about a photon born in the center of the sun? It takes like a million years to leave or something. That means it's keeping that heat in. It's insulating itself. Gotcha. So that's the other kind of neat little trick that the sun gets to pull off by just being a monster. and to a lesser extent that does work with terrestrial fusion as well trying to hold some of that radiation and every little every little fraction that you can capture is a fraction you don't have to pay for so there's inertial confinement so that would be uh weapons and laser fusion and um the z-pinch machine at sandia uh and then there is magnetic confinement which has yet to be shown um that's where they're trying to hold it in a bottle a magnetic bottle

11:40Gerrit Bruhaug: When you say yet to be shown, that means basically having that Fermi pile, sorry, Chicago pile, Fermi self-sustaining.

11:47Decouple Host: The self-sustaining chain reaction. So the NIF in 20, depending on who you ask, there's the DOE line and there's the scientific line. 2021 or 2022, the NIF showed that self-sustaining chain reaction. It did not make wall plug net energy not even close. The NIF is very inefficient. That was very much on purpose. That design was frozen before I was born. I mean, it was 80s laser tech with meant to be affordable. It's about like three and a half billion dollars when it was all said and done. Expensive, but not insane. And they were able to build it. It was big. It's big to this day. It's the biggest laser in the world by a long shot.

12:27Decouple Host: It was a lot of work to make that thing actually function. So the point was just to show you could get that sustained chain reaction or that self heating chain reaction. It's not sustained. It's just a burst. but it's a self-heating chain reaction. Just like when you inject fuel into your cylinder in your car, it's a self-heating chain reaction.

12:49Gerrit Bruhaug: But like a cylinder in your car, you're having to like fire the spark plug over and over again for the fuel that you're putting into the cylinder. I do want to get a lot deeper into inertial confinement, but keep going sort of at this level to explain the magnetic side once you're finished with inertial.

13:02Decouple Host: Yeah. So then the magnetic bottle, the idea there is, so for gravitational, we go time, size, slow burning thing, like a pot, like a fricking compost pile or a, um, you know, a, uh, like a underground coal fire or something. They're crate. It's just big and slow. Inertial confinement is these big, these rapid flashes of energy. Uh, we're trying to slam everything to get it to those conditions. And then it just explodes. Magnetic confinement is kind of trying to cut the difference. The idea is we can't hold this stuff's way too hot. It would eat any material known to man. You also don't want metals to get into your plasma.

13:41Decouple Host: That cools them off really fast. The radiative cooling goes something like the Z of the elements, like the atomic number of the elements squared. So as you start to get things above hydrogen in there, your plasma just drops in temp really fast. So you can't hold it physically. But what you can do is plasmas respond to electric and magnetic fields. So you try and make a magnetic bottle. There's a bunch of really complicated reasons why you can't make a simple magnetic bottle and why plasmas leak. And we've spent decades and decades and decades trying to come up with better and better magnetic bottles.

14:13Decouple Host: But the hope there is to do these long confinement times, like seconds versus picoseconds for inertial confinement and hold it, hold this fire for a little bit. Now, they always you always see it in science fiction is like this constant run. Nobody can do that. There's no plans to do that right now. There's a bunch of complicated technical reasons why any magnetic device is pulsed, but it's pulsed slowly. It's like turn on, couple seconds, turn off, turn on, couple seconds, turn off. The goal is to try to get more like a continuous burning furnace. but still, you know, there's a bunch of reality in there.

14:54Decouple Host: And they are low density, very hot, hold for a long time. So you have this, we're back to that Lawson criterion, right? This triple product, multiplication of pressure, time, and temperature. You pick which ones you want to maximize to get the number. ICF goes for pressure and to a smaller extent temperature and also cheats by eating some of that radiation. um mcf magnetic confinement goes for time and temperature and the pressure is pretty low it's like an atmosphere a couple atmospheres of pressure versus oh wow natural confinement we yeah natural confinement we go uh way beyond the sun the temperatures are um definitely hotter they're not like wildly hotter than the sun mcf goes like wildly hotter than the sun and then uh now that we get into the the real interesting bit too is as you get into self-heating this is the thing that, um, the real important part is the self-heating because you don't want to pay for all that energy constantly, magnetic or inertial.

15:51Decouple Host: You're always paying for that energy and you're paying a lot of, a lot of energy, a lot of money that you would like to not be doing if you want to make a power plant. Um, so we look at the NIF right now, they've gotten up to like eight-ish megajoules of fusion out for two-ish megajoules of laser in. Um, that sounds like a pretty poor, trade-off. The NIF is marginal. It's an important thing to remember. We made it the minimum size that we thought could work. It was actually a big debate in the 90s where some of the national labs would not sign off on the design because they didn't think it could happen.

16:24Decouple Host: The NIF, we put in our two megajoules of laser. It converts to like 200 kilojoules of x-rays, which then converts to like 20 kilojoules, 25 kilojoules of actual like heating. So it's super, super inefficient. But the point was you're getting the center of this thing up to like a couple, um, we use K EB is our temperature. So we get it to round numbers. We'll say 10 K EV temperatures. Um, that's the, you know, energy we put in. And then as it lights, even in this marginal, like barely working, it's like a sputtering engine level of operation. Uh, it jumps and it goes like factor three, four, five, six in temperature, uh, because that chain reaction starts to self-heat.

17:06Decouple Host: And now you're getting, you know, rather than putting in KEVs of temperature, you're getting MEVs of temperature back from fusion. And the idea is if you get good enough with this now, rather than putting in two megajoules of laser and getting eight megajoules of fusion out, you'll put two megajoules of laser in and you'll get like 500 megajoules of fusion out.

17:26Gerrit Bruhaug: And sorry, the laser was being charged with how much? So we put two in, we get eight out, but the laser is consuming how much?

17:32Decouple Host: It's like 300 megajoules. It's real inefficient.

17:34Gerrit Bruhaug: Okay, so we're not netting anything, but we're getting a sustained chain reaction, essentially.

17:40Decouple Host: All for the science. Think Chicago pile. Just think about the fact that if we want to be pedantic about it, Chicago pile, all of the lights and other stuff in the building consume more energy than that reactor released. Yeah. The point was to show the reactor could sustain itself, not that it could power the building. and magnetic confinement still has to do that i feel good that they're going to get there at some point soon but they are they're a bit behind the curve on that one just to go back to like super

18:10Gerrit Bruhaug: first principles um so obviously with fission we have these unstable nuclei with you know tons and tons of neutrons you add an extra one in and essentially the electrostatic forces all that positive charge of those protons there's some energy added and the the nuclei sort of like deform slightly. And then the electrostatic forces, I believe, overcome the strong nuclear force. Boom, splits apart. Lots of particles come out, you know, alphas, betas, gammas, and fission products, which continue to decay, create heat in this big, you know, often ceramic kind of core in terms of the fuel. And we strip the heat away there.

18:45Gerrit Bruhaug: With these fusion reactions, from what I understand, the reason that you need, I think you said Lawson's ingredients of heat pressure criteria yeah loss is criteria um is because we need to essentially like ionize um our hydrogen um and then have enough kinetic energy um that it overcomes that electrostatic repulsion and fuses together my kind of there so yeah yeah um and and circling back you you brought

19:14Decouple Host: up on um you know uranium and all that other stuff's unstable uh if we look if you've ever seen the chart of the binding energy. So this is like stability for nuclear things. On the right, you have all of the unstable high Z stuff. And on the left, you actually have a bunch of low Z things that are also unstable. The most stable thing out there is about iron. And that's why fusion is energetically favorable is things are trying to get to iron. They're either trying to decay and fission down to iron or they're trying to fuse their way up and that also explains why certain reactions are way more likely than other reactions because helium normal helium that's in our balloons helium-4 is like a weird spike of stability and it doesn't really want to react but a lot of things want to become helium-4 so that's why most fusion reactions make helium um but eventually like in stars they're burning it all the way up into iron so the um you know You have to get the temperature.

20:14Decouple Host: It's because atoms don't want to get close, like nuclei don't want to get close together. They're very charged. If we could not ionize our fusion fuel, we would. That would actually be great to not make it a plasma. We don't have a choice because the only way to get it fast enough, to get them close enough to then use quantum tunneling, weirdly enough, is the only reason this even works, is to get them so hot that it has to become a plasma. there's just the electrons can't hang on and so we're just basically trying to speed things up enough that as they bang around they eventually go touch fuse and the strong nuclear force now overcomes the electrostatic force it's the inverse of what you were just describing in fission

20:53Gerrit Bruhaug: okay and then the products created through that fusion reaction were not necessarily betas or gammas or there's not fission products that are coming out and having daughter products and releasing heat. To my understanding, it's alphas and neutrons. And tell me about the different roles of those two products.

21:12Decouple Host: Yeah. So the primary reaction that we all talk about, and we can get into the other ones, but the main one that everyone is, or that is the main focus of fusion research on Earth is deuterium tritium. So those are the two heavy types of hydrogen. Those have the highest cross-section, so highest probability of fusion at the lowest temperature. It's still absurdly high, but it's literally like an order of magnitude lower than the other ones. So it's worth going after. That makes an alpha particle, so helium-4, back to the stability thing, and a very, very fast neutron. It's a 14-MeV neutron. With fission, we're thinking more like 2-MeV, and then we thermalize them down to room temperature effectively, which is 0.02 EV or something like that.

21:58Decouple Host: this 14 mev neutron is flying it wants to wreck things it it knocks other neutrons off of atoms very regularly and easily which is actually a very helpful bit because you'll notice tritium is radioactive and does not stick around so if we you know the only way this can work is we have to make more tritium with that neutron and if you just think about the accounting of i get one neutron per reaction and then one neutron can make one tritium that's never going to work it's like reality reality is going to like drop that number below one you know perfection right you're going to lose like if you've ever dealt with tritium it's a slippery little sob it'll just leave you try and get it out of your system and it's like soaked into the metal or whatever so one of the things we rely on or that ideally nobody's done this yet breeding is one of those challenges we have to show for fusion, is the neutron will go and rip some more neutrons off a friendly, say, lead or beryllium nuclei, which we know it's very good at doing.

23:02Decouple Host: And then those neutrons can go find some lithium and make you tritium.

23:07Gerrit Bruhaug: So that kind of gets us to the fuel. And I think in popular culture, in the same way that people sort of think about hydrogen as like it's fuel from water or something like that, right? I mean, it creates water as a product, obviously, but, There's a lot of simplistic ideas about how it can substitute for methane really easily when making the hydrogen fuel is not impossible, certainly more easy than making, I think, fusion fuel through electrolysis or steam methane reforming. But talk to me about DT fuel, because again, people, I think, make a similar sort of category or like, hey, this is just kind of products of water.

23:44Gerrit Bruhaug: It's hydrogen. Just smash it together. how do we you mentioned this way of making tritium obviously we can also give you a little bit from our can-do reactors up here in Canada

23:53Decouple Host: we are very much relying on the can-do's that is the whole fusion world is banking on can-do's existing

24:00Gerrit Bruhaug: but it seems that making the fuel is tricky and expensive like making heavy water for can-do's is again not hard but it's expensive like I learned recently that to make a load of heavy water for a sort of gigawatt scale can-do plant consumes about 1.3 terawatt hours of electricity and probably the method where most likely the processor most likely to produce it. So it ain't free. Um, and, and tritium seems hard as well. So just maybe, um, like we we've done some episodes on just, um, um, low enriched uranium, uh, type type fuel. And, you know, we've called it the Swiss watch, uh, of fuels in terms of, uh, the elements, um, the zirconium cladding, the geometry, et cetera, unlike combustion fuels, which are destroyed and fundamentally sort of transmuted when put through a power plant, like the fuel element has to kind of leave without any, you know, flaws or, you know, leaks or cracks where fission products could leak out.

24:58Gerrit Bruhaug: So let's just nerd out a tiny bit on fission fuel. And it's going to be quite different, obviously, for inertial confinement versus magnetic confinement. But let's jump into those stormy waters and try and figure this out.

25:10Decouple Host: To kind of riff off some of your previous episodes with uranium fuels as well, real quick, let's touch on the three fusion fuels that are worth talking about because they do. I'm sure there's somebody that's going to yell into their car stereo that I'm ignoring their favorite weird esoteric thing. But the reactions that we know work. DT. We know DT works. Has been proven many times. Deuterium, deuterium. Also, we know works. That is just heavy, you know, basically the products of heavy water burning together. And then deuterium helium-3, nobody has ever ignited that reaction, but we're pretty darn sure it works.

25:46Decouple Host: There's a bunch of, we do actually shoot it relatively regularly on some facilities. It's harder to get ignition than DT. Like I mentioned, DT is the easiest. But deuterium helium-3, we are positive, will work if you reach the conditions. It will self-heat. It will make net energy. so of those dt is the easiest to get to light and has the um well i would argue the biggest pain in the ass fuel because deuterium as you mentioned comes from heavy water it's kind of expensive to make heavy water we're not going to be burning that much of it though um the the cost of deuterium when i've seen this spec'd out it's like ah it's whatever it's not really it's not going to kill you um that's pretty cheap stuff comparatively for like the energy you're going to get, right?

26:33Decouple Host: And so that's why ideally, if we could ignore all the complexities of making the reactor, you would just burn deuterium, deuterium. That's your low enriched or natural, that's even like your can-do of fusion reactors. If you can burn deuterium, deuterium, you're literally burning the products of water. It's easy to deal with. It's easy to get. It does make slightly different exhaust products than DT, but not enough to matter. You make helium, you make protons, you make neutrons. You could just exhaust it out into the atmosphere. Wouldn't matter. Um, DT, we have our product of water. That's, I'm going to say not that bad.

27:10Decouple Host: And we have tritium that we have to make because it has a 12 year half-life. We can't store it up. It is made by cosmic rays, whatever. You're not going to pull enough out of the atmosphere for that. And we can get some from our friendly can-dos. But, uh, last time I looked into this, the entire world heavy water fleet could supply something like 20 megawatts of fusion power constantly with their tritium production. So we're not pulling that one off. The most we can do is we can use the tritium from CANDUS and other sources, because there is tritium bred directly in reactors for national security purposes sometimes.

27:49Decouple Host: We have to use that to kickstart a breeder cycle, just like the uranium-plutonium breeder cycles. you know you put a little bit in and then ideally you're multiplying and multiplying and multiplying so we'll do that neutron multiplication we mentioned and then those neutrons have to go find some lithium and they can make tritium from the lithium now ideally what you'll see a lot of people talk about is lithium six which is about seven eight percent of all lithium it's expensive to enrich to i'm not gonna not gonna bs you on that one part of that is people don't enrich very much lithium. You could argue that we could definitely drop those prices if there was a large lithium enrichment industry.

28:32Decouple Host: Right now, it's a niche product for balancing pH and PWRs, and that's about it. But even better would be natural lithium. And the fun part is, actually, that totally works. Natural lithium right out of the ground is also cheap. People will talk about conflicts over lithium as a critical mineral, but it's nothing like Some of those other battery minerals, right? It's all over the place. And when you're talking about the amount, you know, fusion is still nuclear. When you're talking about the amounts you need for a fusion reactor, it's like, I don't know, man, you could get it from a crap source and it still wouldn't matter if your fusion cycle was working.

29:08Decouple Host: Like we're, you know, we're assuming we have our working reactor here. The hard part, though, is that you now you make your lithium, your lithium's in a salt or a solid or a liquid metal form, whatever, whatever crazy reactor concept you have. Now you have gaseous tritium. Or it's bonded chemically. And you have to pull that tritium out. So you have to have a chemical processing facility. It is always going to be, it's going to have to be some sort of online thing because you're not trying to hold a lot of tritium. And then you have to re-inject it back into your system. And there's a whole game about how much tritium you have to hold versus how fast you put it into what's called the tritium inventory.

29:49Decouple Host: and people are very very worried about the tritium inventory because tritium is not easy to get the can do's will give us some but you guys don't have you know thousands of kilos to hand off you don't want to have thousands of yeah you don't want to have thousands of kilos it's gaseous and likes to fill the room if it leaks um and uh you know it just literally makes heat because it's decaying it's decaying pretty pretty darn fast and so that's another game in this whole trying to optimize a reactor is how can you lower your tritium inventory how can you burn the most tritium or the tritium most efficiently to keep that number down but this this is like you know if we say the if we say the the burning deuterium deuterium is our can do type fusion reactor if you can make it work but unlike the can do it's harder so it's like the better fuel but the harder reactor.

30:41Decouple Host: DT is, is definitely the breeder cycle. It's full, it's fully comparable to the breeder reactor. It's all the complexities of the breeder reactor, but now the reaction's way easier to make, to light off. It's, it's more like dealing with highly enriched uranium or something where it's like, yeah, kind of, I'm not going to say any idiot because fusion's really hard, but it's a lot easier to make a DT reaction work than a DT reaction. And then just like real quick, because it'll get brought up. D-helium-3 is like weird sci-fi nonsense because there is no supply of helium-3. People who say you can mine it off the moon are smoking something good.

31:17Decouple Host: I actually have a paper that I wrote about why that's stupid that I can send to you about why the energetics of that don't make any sense. But yeah, helium-3 is something that gets brought up for science fiction every now and then. It's all the complexity of dealing with DT, but all the fun of having to go find your fuel out in deep space.

31:36Gerrit Bruhaug: Okay. Okay. So, so, so far we've talked about, I guess the equivalent to fission would be, um, you know, whatever mining, milling and enriching and, you know, converting, sorry, converting and enriching, whatever, making what's inside the, the, the fuel cladding. Um, but let's talk about what that actual fuel element looks like. I understand it's going to be quite different for inertial confinement versus, uh, magnetic confinement. Um, uh, so what does it look like? How do you make it? Um, and then why do you need to, why do you need to

32:03Decouple Host: freeze it to to use real broad easy terms here magnetic confinement um they trade a lot of complexity that we can get into later by trying to make their but the the trade-off is their fuel is going to be a lot easier the the general gist is you could just spritz in gaseous fuel um super easy it's you know a glorified carburetor uh they actually do inject frozen pellets for all sorts of fun complicated like plasma physics control reasons and it gets very very neat they They have these like rail guns that shoot into tokamaks. But, you know, overall, their fuel is pretty simple. They go for very, very, very simple types of fuel.

32:42Decouple Host: Inertial confinement needs high quality fuel and it's bigger. You know, think like Trezo pellet sized, but now getting bigger as we're going away from the NIF. There's a whole there's a weird trade where the smaller the laser, actually the harder the target is to make or the smaller the thing doing the compressing. because the z machine also does inertial confinement um because you have to be more perfect with how you do everything because you have less like margin but so it's these little we'll talk laser confinement um there are these little tiny pellets uh what the outside of the pellet is varies on your design it can be plastic uh the niff likes to use diamond i said they have to be perfect they get diamond pellets sent from germany of course it's from germany oh it's the only place that can make them uh and um and these are like polished and the surface tolerances are

33:32Gerrit Bruhaug: like down to the oh very very nice yeah okay uh interestingly enough i was looking it up though

33:37Decouple Host: the surface the surface tolerances are better than trezo but they're not like wildly better we're not talking you know four orders of magnitude we're talking one to two ish and actually as we get bigger um we'll start getting to like trezo levels of quality on a on a bigger pellet as laser gets bigger and pellet gets to get bigger and everything gets a little nicer.

34:00Gerrit Bruhaug: So what is the size of a pellet at the at the NIF? Is it a couple of millimeters?

34:04Decouple Host: Yeah, like a millimeter scale pellet of fuel.

34:07Gerrit Bruhaug: We have this diamond casing and then I heard you need to like drill it, hollow it out and fill it up with gas. Is that?

34:13Decouple Host: So it actually comes hollowed out. Don't ask me how they do that. I have no idea.

34:17Gerrit Bruhaug: Thanks, Germany. Yeah.

34:18Decouple Host: Yeah. And there's other things other than diamond that are used, but like diamond is the classic fun one to talk about. And it's got the highest performance on the NIF. They dope it. So they'll often like spray it with beryllium or something like that to get the right x-ray absorption. And then it's already got a little hole in it that we call the fill tube. And so we construct this little tiny target. It goes inside its little gold can because of how the NIF has to work. It has to be in a little gold can called a hole realm. We got gold, we got diamonds. Yeah, yeah. What's funny, it's like a nanometer of gold with the outer casing of some other material holding it.

34:57Decouple Host: But like, yeah, we just have to add every expensive thing together. Beryllium's not cheap either. And then they inject in the hydrogen, the deuterium tritium, and it comes in as a liquid and they freeze it into this really nice layer and they actually let it decay for a while so that the decay heat makes the layer smoother. If you've ever seen, think like you're Canadian, you must love hockey, that really pure, beautiful ice that you kind of have to remelt to get it to do that. But it's literally what they're doing.

35:24Gerrit Bruhaug: When you say freezing it, we're not taking it down to like minus 4, minus 10 Celsius. We're going to...

35:30Decouple Host: Oh, no. It's 18 Kelvin.

35:32Gerrit Bruhaug: Woo! Okay.

35:33Decouple Host: Very cold. Very cold. It's funny. There was a bunch of stuff done to like figure out how to make that perfect ice layer faster. But because the NIF can't shoot very fast for all sorts of reasons, it's actually just easier to let the tritium's own heat make the ice really nice. So these pellets, they age like wine.

35:53Gerrit Bruhaug: just to get my head around it because i didn't have it we we have covered this before and people should go back to that episode if they're feeling overwhelmed um but i think it is really important to kind of overwhelm people because if you only get this at a surface level um i mean you're missing you're missing a lot of uh trees inside the forest yeah the devil's in the details on fusion totally right so you got this like two millimeter um capsule with some like i think it's quintillions of individual deuterium and tritium atoms. And then the laser is kind of heating the center of it and starting to fuse a few of those.

36:26Gerrit Bruhaug: I'm not sure, like a quintillion or something. And then the rest are starting to ignite.

36:32Decouple Host: The laser is heating nothing. This is the fun part because I know you love engines.

36:36Gerrit Bruhaug: Oh, x-rays, baby. Yeah.

36:38Decouple Host: Yeah. So the laser comes in, it hits the gold can and it makes x-rays. And the whole realm is, it's German word for oven. It's an x-ray oven. And there's a whole bit about how you make that x-ray drive. And the x-rays are actually ablating the outside. They're ablating that diamond off. And it's a rocket. It's literally a 360-degree rocket compressing this in. And it's a diesel reaction. We're literally just doing, you know, pressure, compression work. That heats it up. That drives your density through the roof. And the very center starts to get to that Lawson criterion. It starts to light. and that burn wave goes out and it's just like in a diesel engine.

37:18Decouple Host: It is fusion diesel is what you're doing.

37:21Gerrit Bruhaug: So like an isobaric? I don't want to get too much of the diesel engines.

37:24Decouple Host: You are trying to do the most perfect compression possible. We spend an absurd amount of money and time and effort thinking about how to compress this thing as perfectly as possible because that drives your energy. The more perfectly you can compress, the less energy you have to put in and the better the reaction is.

37:44Gerrit Bruhaug: Okay. And then, so in terms of like, when we're talking ignition, like, I mean, just thinking about like, I don't know, like a fire, like a campfire. That's what I'm most familiar with in terms of energy. You know, I'm a cowboy trapped in a city. In any case, in terms of what was achieved at NIF, like, I think people's perception might be that this, you know, produced energy and it went on for, you know, you hear about records being set at Tokamaks and it's going for hundreds or thousands of seconds, I believe. 22 minutes, I think, is the world record. um in france um but so we were we were we threw these x-rays starting to fuse some of these dt atoms and then it was sort of sizzling and spreading through the rest of those quintillions of dt atoms or i don't know nuclei atoms i'm getting confused here um and then it's over so so in terms of like how long that ignition lasted for are we talking like nanoseconds picoseconds

38:35Decouple Host: The laser turns on round numbers here, 10 nanoseconds. That's the drive for the cylinder. And then the reaction, all of that energy is released in about 50 picoseconds. Wow. Just boom. It is an explosion. The peak power of that thing is insane. It's like many, many petawatts of peak power as it goes off.

39:02Gerrit Bruhaug: and so again basically we're setting off a bunch of little hydrogen bombs pretty much yeah how many do we need to settle if we were going to try and sustain this for seconds or minutes how many of these little inertial confinement fuel capsules do we need to be hitting with the laser per second

39:18Decouple Host: minute i don't know so we wouldn't do it like the niff like i said the niff is marginal we would we would build as many companies are trying to do a um a bigger facility and a bigger facility would get more gain. So you would get a lot more fusion for the same amount of laser you put in. Gotcha. Yeah, the lasers are more,

39:37Gerrit Bruhaug: they're not 1980s fishing lasers.

39:39Decouple Host: It's not only that, this is a non-linear process. So as you get, as you compress it a little bit harder, we made our laser a little bit bigger. We made our capsule a little bit bigger. We get many, many times more energy out. And that's one of the pain in the asses of the NIF is the NIF is like right on this ragged edge. You're just, you're getting this coughing start on the engine rather than like a big, smooth diesel running. So you'd make it bigger. You'd make it frighteningly bigger, to be honest. And to make a power plant, you're going, oh, we would be setting off like the equivalent of hundreds of kilos of TNT worth of explosion every time this thing fires.

40:20Decouple Host: Every shot. Every shot. So you're talking about very big explosions at this point.

40:27Gerrit Bruhaug: so how big are our fuel capsules now if they're a millimeter so now we're now we're talking say

40:32Decouple Host: like um rather than one millimeter it's a couple millimeters across okay it doesn't need to be that much bigger um but now you're starting to talk you know like gigajoules of rather than eight megajoules gigajoules so for some context four gigajoules is a ton of tnt um and and also that's kind of a wild thing to think about that a normal nuclear power plant is also releasing a ton of tnt about every second. So it's like the scale is still is the same. It's just you have to now do this with a glorified diesel engine effectively. So you're doing this once every second, a couple of seconds. There's a big like trade space that people are looking at as to what makes the most sense on how you design the system.

41:18Decouple Host: I mean, we've never done this, right? We have explosion powered engines, but nothing quite of this scale. The closest you could look at as like big cruise ship diesels.

41:27Gerrit Bruhaug: Marine diesels, yeah. Yeah, marine diesels.

41:29Decouple Host: But even those are still, we still got to go like an order of magnitude above those in energy release.

41:34Gerrit Bruhaug: And again, your energy release is like 20 % alpha, which sustains the ignition, sustains the fusion reactions. Although that all comes out. Of the individual fuel pellet that lasts for like a second and then you need that next laser pulse. So there's always, okay, like there's energy being delivered by the laser transformed into x-rays, which triggers each new capsule to go. They're igniting. They're producing lots of alpha, which is helping the rest of the fuel capsule sizzle and fuse. Compared to a magnetic confinement situation where you're spraying in deuterium, tritium gas, you still have a big parasitic load, a lot of electricity going into cooling magnets, control systems, running your breeding, whatever else.

42:18Decouple Host: You have to heat the plasma too. So the magnetic systems, we'll circle to those.

42:23Gerrit Bruhaug: But once it started, you're not needing to continuously input new kind of laser blasts. The ignition seems like it lasts longer under its own power or no?

42:31Decouple Host: So that's like the dirty little secret in a lot of these magnetic systems. In theory, you can get what's called Q infinity, where you could have your bottle be perfect and you get your plasma hot and your plasma just self-heats and runs and you have your perfect little like balanced fusion furnace. Nobody has any idea how to do that. If that's even possible, because there's so many instabilities that the plasma drives, that the fusion will drive in the plasma. The current way that they're going for it is you inject in your fuel, you spray your gas, you do a bunch of different steps of heating.

43:07Decouple Host: You're using microwaves and particle beams and big pulses of current and all this other stuff. Oh yeah, that's pretty crazy. they get it hot and you hold it for however many seconds and to be honest as you get to the self heating portion where it's going to give you energy out it's going to be shorter pulses that 22 minutes that whenever you see like a tokamak record or any kind of mcf record um it's usually a good rule of thumb that the rest of the conditions are pretty crap it's probably pretty cold pretty low density very far from doing fusion um so when you're going to get to this self heating they're going to turn it on they're going to get it up to that furnace condition they're going to hold it and they hopefully don't have to heat that much.

43:43Decouple Host: They probably are still heating. Some aspect of heating is still going on, but the plasma will self-heat and it will make more energy than you're putting in if you set it up right. And the kind of general rule of thumb as people are getting more realistic with these designs, like we're getting to the point where we know enough where the designs that are being published, the machines being built are believable that they're going to get the numbers they think they're going to get. um icf any any kind of inertial confinement gets uh very high gains hundreds of times the energy you put in which you need because your drive your laser or your pulse power is probably more on the inefficient side mcf magnetic confinement gets pretty low gains spark the make the guys at mit I think they're going for five, maybe 10 X over that versus, you know, for ICF, we're talking like 200, 300 sort of gains.

44:45Decouple Host: And this all circles back to the real killer. I think the two killers on fusion energy, they're going to tell you if you can get anywhere are tritium inventory and gain your actual engineering gain. What is that parasitic load like you brought up? Because a power plant can have a parasitic load. I went and looked this up. An AP1000 puts about 8 % of its power into parasitic load.

45:07Gerrit Bruhaug: So running reactor coolant pumps? Yeah.

45:09Decouple Host: Okay. And you could probably put another, you can probably round up and say another 2 % into the rest of the facility. So if you're at about 10%, you can survive it. But that puts some harsh numbers on the rest of your system, right? It means your efficiency has to be high and or your gain has to be high. The multiplication of those two things has to be pretty darn high because you're still getting this out as thermal power, right? In the end, you're heating coolant. You have to go through a turbine. So you can already knock about.

45:41Gerrit Bruhaug: Okay, yeah.

45:42Decouple Host: Yeah, you can knock like two-thirds of the energy off as just heat that you don't get to use. Shit. So that you can see why like the economics of this are brutal. If you're going to do it, you have to drive that gain in efficiency as high as possible.

46:01Gerrit Bruhaug: Okay. And I mean, in terms of, again, your power conversion, it's that's neutrons being absorbed by something, whether it's just like a ceramic, a molten salt. Yeah.

46:09Decouple Host: Cause we have to stop our neutrons to make tritium. We don't want to let any neutrons out very fast.

46:15Gerrit Bruhaug: Yeah.

46:15Decouple Host: Yeah. We got to stop them in our breeding blanket. Some of them will heat other things, but ideally they're stopping in the breeding blanket. the rest of the energy, you talk about the alphas, the like 20 % of the energy that's alphas and whatever you put in, of course, whatever you put in does come back as heat. That basically all comes back as x-rays. So that has to be absorbed into the wall or some sort of surface that's going to be facing the plasma. They call it plasma facing surfaces or like a big area of research. All of that turns into heat. Every bit of it is heat that you then have to do a normal thermal cycle on.

46:54Gerrit Bruhaug: Is it hard to reject some of that heat? Like it sounds like the neutrons might be easier versus the alphas.

46:59Decouple Host: Unbelievably hard. Yes. So, okay. It's not a decay heat

47:02Gerrit Bruhaug: when you shut it off. Like it's not going to last and be the nightmare that management is an efficient plant.

47:07Decouple Host: There is also decay heat, which we can get into. But if we're talking about like the initial heating, the initial heating load. So if we go ICF, I said it's a really high peak power, right? So you have to be very careful on how close your walls are so you don't ablate the walls back into the system. ICF gets to have a very simple chamber. We can just have a big steel vessel. We don't have to do anything crazy because we're not holding magnets. The lasers come through holes, that sort of thing, right? The lasers are safe. They're far away. But the chamber is withstanding a big explosion. So you have to think about how you're going to protect it from that horrible x-ray blast.

47:46Decouple Host: The neutrons are also a problem, but the x-ray...

47:48Gerrit Bruhaug: It's not a pressure wave explosion. It's an X-ray blast.

47:52Decouple Host: It's an X-ray and neutron blast. And then you might have a lot of these designs involve flowing coolant in the chamber. In which case you can turn the X-ray blast into a pressure blast because you would rather have a pressure blast than an X-ray blast. An X-ray blast, if you're just taking an X-ray blast, like on the NIF, right? We know the NIF was never meant to run forever and it's not meant to be a power plant. But we know as we get more and more fusion out of it, it damages itself. And there is a lifetime that you could put on it as to how many shots before it will have just like burnt through its walls.

48:29Decouple Host: So you don't want to do that. Magnetic confinement has an extra problem of the plasma exhaust has to come out. That helium ash. So in ICF, it's just all blowing out. You don't really care. It goes evenly in all directions. And it's not a big deal compared to the x-rays. MCF has the neutrons which are you know their own nightmare because their magnets are close your magnets are now having to deal with the neutrons x-rays hitting stuff which you get in every direction and it's not a blast but it is a lot right like a gigawatt still a gigawatt no matter how you're going to do this and then the plasma exhaust itself which has to come out to keep let the reaction keep running for seconds you have to throw that helium somewhere and it's it's coming as a horrible jet.

49:16Decouple Host: There's always these like closed field lines where the plasma goes. And at the diverter, that's the component they call where that jet of plasma, that's what they call it, where that jet of plasma goes on like a tokamak or a stellarator. The heat loads are equivalent or worse than reentry from space. But it's a jet of plasma hitting it and there's radiation. so it's uh it is a challenging engineering problem to put it lightly it is a fun engineering problem but it is a challenging engineering problem and that's um things like that have colored my you know there's a reason i work on the kind of fusion i work on you've made your choice yeah yeah i i am very entertained watching my colleagues talk about this stuff and i am rooting for them but boy, some of those problems are hard.

50:07Gerrit Bruhaug: Right. Okay. So I think we've, I mean, there's like an infinity of depth we could go into. And I think we've gone into a good amount of depth in terms of, you know, what fusion is, what, and the devils of the details of the fuel and the devices themselves, et cetera. I want to switch a little bit into talking about, I guess, like development. Like we talked about the initial sort of bench experiments, if we want to call them that. Like we've had tokamaks for a long time now, right? Like the Soviets had a tokamak going 50s, 60s?

50:46Decouple Host: Late 50s, I believe is when it was invented.

50:49Gerrit Bruhaug: Like that's wild. They've been around for a long time. Okay. And in terms of inertial confinement stuff,

50:55Decouple Host: we've had that since depends when you want to put the start date but yeah similar i mean the the the famous john knuckles paper which like talked about friendly inertial confinement uh is also that that same time frame to be fair the laser wasn't invented till the 60s and the first um the first laser fusion this is like a fun historic thing for you first laser fusion ever was done by a private company and the first ever fusion startup. KMS Fusion did it out in Wisconsin because when those initial laser fusion papers came out, everyone looked at this is before we learned the realities of how hard this is.

51:35Decouple Host: They looked at it and they went, oh, my God, we're going to make laser fusion. We're going to do it in like a decade. This is going to work so easy. This is going to make all this magnetic stuff look like a joke. And here we are in 2026, and that didn't quite work out. But it inspired some people to actually take a bet on fusion energy back then and make a startup that got in trouble with the AEC. There's a whole huge crazy history there. And the CEO died testifying to Congress. I mean, it's nuts. But that was the...

52:09Gerrit Bruhaug: Died during testimony to Congress?

52:10Decouple Host: Died during his testimony.

52:12Gerrit Bruhaug: Did he have like a CIA dart with the jelly poisoner?

52:15Decouple Host: He was a bigger man who liked his hamburgers and it eventually caught up to him. Wow. But yeah, it's a wild story. I would highly recommend looking it up. Alex Wallerstein has it in one of his books, KMS Fusion. So yeah, we have decades, decades of work on this, this initial, all of these projects started a long time ago. And what it really was is initially we all thought it was, you and I weren't alive. everyone thought it was gonna be easy they were riding so high off fission and the bomb and even like the initial hydrogen bomb work they were like dude we got this this is gonna be nothing we're gonna have fusion reactors by like the 80s at the latest and there's project sharewood which was the classified u.s project on it because we went oh we're gonna get fusion so fast we we better keep it classified so we can keep ahead of those damn dirty commies and uh we learned that there is a lot of challenges in plasmas and eventually you know everyone had to start sharing and talking and um collaborating more and more and right at the end of the cold war that accumulated in the agreements that later became eater uh between reagan and gorbachev to make this because um you know as as money got tighter there's there's like infinite versions of fusion reactors we can talk about we could talk for days um but they started to kind of narrow down tokamaks were starting to get the performance that was needed um laser fusion uh still looked promising and had connections to the weapons program so it was going those two were the ones that were just going to keep eking up right and um yeah they made these these big agreements uh kms fusion sadly went under and they didn't get that far on laser fusion but um and then uh they you know we started getting into the aughts and that's when the first fusion startups actually came out as and you started to see more work outside of Eater more people getting I think people were getting frustrated with Eater and NIF kind of like eating all of fusion interest and I think that's probably what drove a lot of these initial startups there's the one in general general fusion up in Canada TAE technologies down in California those were like early aughts those were scientists who liked some of these old ideas thought we should revisit them and push that you know we're able to convince investors to to take a honestly crazy risk especially at that point and it's just been building over the years and it's been very interesting like being like kind of coming up in this field and seeing as the um as the money's building as the interest is building

54:58Gerrit Bruhaug: how much money is building like it's it's tens of billions let's see what is it 17.4 billion is

55:05Decouple Host: what i saw yesterday uh since 2010 has been invested in diffusion on the private side like

55:11Gerrit Bruhaug: is that a lot or a little because you hear like um you know the development cost the ap1000 i mean the design wasn't done when they started vogel but was you know in the billions that is

55:21Decouple Host: the correct question it's both a lot and a little and that it's it's crazy that there's that much private money and it's cool that it's pushing forward so many things that got dropped there's a lot of these ideas that you can argue got dropped for politics as well like there's big science i can i can tell you big science is full of big politics um and so it's it's exciting on that hand to see this i think also because basically all the money is in the u.s and china there's like about 10 billion's been invested in the u.s five-ish billion in china and then we have our government programs, of course, like those haven't exactly gone away.

55:59Decouple Host: Um, I think part of it is a, is a prestige play too. And you know, there's, there's a, there's an interesting interplay between the private sector and the public sector, both in the U S and in China, where it's, it's a little hard to tell like who's pushing who forward. Um, but yeah, we're, we're continuing to see lots of billions. And specifically I want to call out, I'm pretty sure CFS, which is that tokamak group out of MIT is the most well-capitalized private nuclear company, like private nuclear startups. This is Commonwealth Fusion Systems. Commonwealth Fusion Systems, yeah. They just raised yet another billion.

56:34Decouple Host: They're at, it's like five, six billion that they've raised over the years. For magnetic confinement. Yeah. And that's far more than any, even any of these fission startups. I mean, Valar just announced a billion raise. that was after they got a critical system. Commonwealth is still putting together their first tokamak. So it's kind of wild. I think it shows the power of the zeitgeist of fusion. Like it's been in science fiction so long, it's been the source of energy of the future so long that it definitely captures the imagination for these investors.

57:16Gerrit Bruhaug: Independent analysis only works if it's independently funded. If Decouple provides you with energy literacy on demand, please consider supporting it. Become a paid subscriber on Substack or make a tax-deductible donation on our website, decouple.media. Join the community. Keep the lights on. Preferably nuclear. Now, back to the show. Okay, so in terms of what's been achieved so far, you mentioned we've had our Chicago pile moment with laser confinement at a government lab. You're obviously working in the private sector in that area now. magnetic confinement still needs to hit ignition. What do we need to do to move towards engineering break-even, which I understand is sort of the plant produces, you know, as much or a little more energy than its parasitic load, and then into commercial operation in terms of, you know, getting lots of electricity with acceptable cost and reliability.

58:12Gerrit Bruhaug: What does that look like?

58:14Decouple Host: There's a lot of these plans out there. There's DOE roadmaps, there's roadmaps for these companies basically everyone is going for their engineering break-even um it's a little wild with the magnetic folks although they will tell you that they knew enough how can you skip ignition and then yeah they'll they'll tell you that they know enough from um previous tokamaks and i i'm i'm inclined to uh i'm not a tokamak guy but i'm inclined to believe the guys at cfs do know a bit about what they're talking about. But everyone else is going for their engineering breakeven facilities. The question is, how do you fund it?

58:53Decouple Host: How do you get it constructed in time? And what else can you get out of it? Because Fusion's expensive. And a big question that a lot of these companies are trying to grapple with too is how do you kind of keep money flowing other than VC money? But yeah, I think engineering breakeven, we're going to see a bunch of those in the next, call it 15, 20 years. There's a lot of reasons to go for it. To be honest, if we build another NIF, if let's say everything dies, the whole industry falls apart, and then we say, well, we need to build another NIF for the same reasons we built the first one, it'll be engineering break-even.

59:27Gerrit Bruhaug: Because more efficient lasers, larger fuel size.

59:32Decouple Host: Yep, exactly. All the right reasons.

59:34Gerrit Bruhaug: But here we're talking about, this is different than ignition in terms of like positive Q, this is actually electricity out. If we're talking about engineering break even. So we're not talking about that right now.

59:44Decouple Host: Ah, yeah. So I'm sorry. Maybe I'm using the wrong term then. So nobody will be making electricity in these initial machines they're trying to make. Spark will not make electricity. Vulcan, which is one of the big laser ones being built. I can't remember what Pacific Fusion's called, but none of those are going to make electricity. The point is they're going to make more energy than all of the energy put into them with margin that if they had a turbine, they could do it. But nobody wants to add, like the thing is, you know, the turbine side of this is not that complicated. It would add a bunch of cost and it would add a bunch of extra pain in the ass for no real win for any of these facilities.

1:00:24Decouple Host: So when people talk about engineering breakeven, it's you made enough fusion energy that if you hooked a turbine up, it would run itself.

1:00:33Gerrit Bruhaug: Theoretically, but why don't you just do that?

1:00:35Decouple Host: uh turbines up what 150 million dollars a um you know a heat exchanger for all of this is expensive

1:00:44Gerrit Bruhaug: it's so no one's making money off of this next step in terms of that's kind of you see you see

1:00:48Decouple Host: kind of the problem you're talking billion dollar facilities that you can't make electricity off of even if you did right like just think about the capacity factor what's the the best case scenario you're gonna like match fortst vrain you're not gonna make any money off of that and and

1:01:04Gerrit Bruhaug: And you're going to be limited by fuel, by reliability issues, by maintaining that plasma in the MCF.

1:01:10Decouple Host: You probably don't have your breeding. You have to figure, you're going to figure out your breeding on these facilities. You're going to prove a lot of your systems.

1:01:18Gerrit Bruhaug: Is that, so is that breeding like easier than like EBR2 where they had that sodium fast reactor and then we're reprocessing the fuel and that sort of horseshoe and through a number of different chemical processings and putting them back in? Is that sort of the level of complexity we're talking about or is it a little easier than that?

1:01:33Decouple Host: It's easier because, should be easier.

1:01:37Gerrit Bruhaug: Not needing heart cells and...

1:01:39Decouple Host: Yeah, well, tritium's a pain, but it's not like emitting huge gammas. Everything's going to be liquid. You get to kind of do this all in this online aqueous processing thing. It should be easier. Emphasis on should. Nobody's actually closed that loop on the engineering end. That's a huge risk. but yeah a bunch of these facilities they're all going to go for this proof of engineering breakeven some people are going to try and make money on the side with other services so if you have a gigantic pulse fusion facility that is getting engineering breakeven levels of gain you could I don't know sell time to the government and especially with the NIF getting old Z getting old things like that so that's but that's never going to fund your company that's more of like

1:02:29Gerrit Bruhaug: offset your costs and that'd be for national security research or yeah yeah yeah uh off and

1:02:37Decouple Host: you can offset you can offset quite a bit of cost on that um but you know that's never gonna that's not a business plan so much as like a cost defrayment plan uh and then after that the next step is a is a pilot plant that's that's what you would call your engineering break even and that's where you will have the turbine, you will have the full kit and caboodle, and that thing needs to take its load of tritium from Canada and never buy more.

1:03:04Gerrit Bruhaug: Okay, question for you here. So I wrote a little bit of a cynical piece on the decouple sub stack. Everyone should drop everything right now and go over there and subscribe. And if you really love the work, then become a paid subscriber. Okay, advertorial over. But I wrote an article on the Antares criticality. And one of the sort of hooks was, there was an interview with, I think, Wall Street Journal with Energy Secretary Chris Wright. And he was saying, essentially, these companies are doing the criticality. That's the hard part. That's the nuclear part. We've known how to make steam from heat forever.

1:03:37Gerrit Bruhaug: That's kind of the easy part. And I was sort of taking a bit of issue with that in terms of looking at, I mean, all the engineering work that went into moving from the Chicago pile to Shippingport or Nautilus. There's a lot there in terms of hooking up a balance of plant, in terms of figuring out the power conversion. How do you think that factors in or in terms of the difficulties of getting to whatever that last stage we just called was, whether it was engineering breakthrough or essentially, you know, a power plant.

1:04:04Decouple Host: Yeah, sorry.

1:04:05Gerrit Bruhaug: Pilot prototype plant fitting on the power conversion stuff. Is that kind of easy? Is that hard? How does it compare to the rest of the efforts?

1:04:12Decouple Host: I agree with your assessment. Balance of plant is not trivial. I think compared to the rest of the problems, it's going to be the easier end.

1:04:20Gerrit Bruhaug: Like you're circulating helium on a gas reactor. You're circulating water coolant at high pressures with ultra high reliability. Like I get why it's expensive and difficult and a huge engineering challenge in fission. Is it somehow simpler in fusion or are you running into a lot of those challenges?

1:04:39Decouple Host: so you're gonna have a lot of the same challenges your one i guess your one argument that it might be a bit easier and where i see a lot of people try and do this or try and push this is um you're going to do you're going to take kind of the uh terrestrial energy or tear sorry not terrestrial energy terapower approach like you you'll be decoupled from the reactor pretty heavily um so you'll have like let's just use molten salt as our example here we have our molten salt breeding loop.

1:05:06Gerrit Bruhaug: So neutrons come out, they hit this breeding loop and melt these salts.

1:05:10Decouple Host: Heat it up and we have our hot molten salt and we also have tritium in there. We don't want that touching our cooling line because tritium can permeate across into the steam, right? So there will be, you have your processing, you have your heat exchanger and you have your processing. Your heat exchanger just goes to another molten salt loop.

1:05:29Gerrit Bruhaug: Just some following along here, you have a sort of like is there a primary and a secondary loop are you having to primary and secondary are you having to pressurize water to prevent it from turning to steam to send it to a steam generator

1:05:40Decouple Host: no so so our prime our primary and secondary loop will be no pressure just hot um so molten salt that's being pumped uh then that with some corrosion issues but not the radiation issues

1:05:53Gerrit Bruhaug: except for a little bit of tritium which is not well and the corrosion issues should actually be

1:05:56Decouple Host: a lot better the main corrosion issues of molten salt reactors was because you make the entire a periodic table when you do fission. Yes. The impurities in molten salts are the big concern, but we're going to ignore that. Assume you solve that or you're using a different coolant or whatever makes you happy. You know, we have our two loops and now we have our final heat exchanger where we boil the water and we run a steam turbine. Most people I know in the industry are talking, let's just match the outlet temperature of whatever steam turbine you can buy for a combined cycle gas plant. and do that.

1:06:32Gerrit Bruhaug: Right. So you have a molten salt. It's going to be in contact with like a water loop, which will then boil, go to a heat exchanger, steam generator.

1:06:42Decouple Host: Oh, no, the molten salt loop has got the steam generator. So it goes to molten salt, to steam generator, and you're just off.

1:06:48Gerrit Bruhaug: Okay. Okay. Okay. Got you. Got you.

1:06:50Decouple Host: Same way that a lot of these fission reactors are trying to do it. Not going to, I'm not going to say that's going to be like super straightforward and bolt on and off. going to work just compared to the rest of the challenges it is one of the less hard ones it's definitely the one where you can go to general electric or somebody else and say help me figure this out rather than i need to invent five new technologies and it's going to make a hotter

1:07:18Gerrit Bruhaug: drier steam that's not going to require those pain in the ass um dryers and rankin cycle yeah Oh, yeah. Oh, yeah. It can work with a gas turbine, sorry, the Rankin on a combined cycle gas turbine, that type.

1:07:31Decouple Host: Yeah, we should easily be able to reach the temperatures needed for, you know, supercritical steam or anything like that. It's just because you're not you're not you don't have to worry about keeping a fuel pellet together or water pressurized or anything like that. It's the same advantages as some of these non-water cooled reactors with some of the same disadvantages, but, you know, different fuel, all that other stuff.

1:07:53Gerrit Bruhaug: a molten salt heat exchanger. Okay. That's going to be interesting. Um, okay. Um, so in terms of, we've sort of talked about, um, you know, what lies ahead in terms of these challenges, I guess I wanted to close a little bit. Um, well, I had an interesting question. So I had the pleasure of chatting with Alex Barovsky. I'm actually forgetting the name of his outfit, but they're awesome. Uh, we'll put that in the show notes. Um, and we had a chat about sort of technological development cycles. And he broke it into this idea of a kind of development triathlon where, you know, the swim is the scientific work.

1:08:28Gerrit Bruhaug: You know, have we proved that fusion is possible in planet Earth? Yes, we've gotten to ignition. There's obviously some more science to figure out, but that's pretty well established. The sort of biking phase, which is, you know, the engineering phase, trying to figure out what's the best way to do this. And at that point, he talked a lot about how there's a lot of divergence that occurs. And we start trying a whole bunch of different ways. And you mentioned, you know, we could spend all day talking about all the different ways to do fusion. It's tended to sort of settle out, as you mentioned on magnetic versus inertial, but even within those, there's some subfactors.

1:08:58Gerrit Bruhaug: And if we were to like, look at the comparison of aviation, we tried a lot of different stuff, right? We had biplanes, triplanes, we had flying wings, all sorts of different fuselage shapes, you know, propellers, turboprops, jet engines, you know, high bypass jet engines. And so that was a sort of kind of engineering phase where it's like, let's play around and try and find all the various ways of skinning the cat. And then we get into this kind of economics and value engineering phase where like, okay, we got to make money off this. We got to commercialize this. And there tends to be a technology convergence.

1:09:28Gerrit Bruhaug: And so if we talk about commercial aviation, you know, that's been towards, you know, these two large jet engines slung off the wings. We're not putting things, you know, in the back of the plane anymore, mounting, you know, off the tail section of the plane. And we've sort of hit this convergence. You could say, and this would probably be my opinion within nuclear fission, you know, we had the discovery of fission, we got the science done, we swam a lot, we hopped on our bike and we tried a whole bunch of different, you know, reactor concepts. In the words of a cranky Twitter commentator, we beat the snot out of this technology, we poured billions and billions in international efforts all around the world, and we farted around with high temperature gas reactors, sort of fast reactors, et cetera.

1:10:11Gerrit Bruhaug: And we sort of have settled in on boiling water and pressurized water reactors. What do you think about that, I guess? And in terms of fusion, what do you think is likely to happen? It sounds like we are in that the bike part of the triathlon. We're in the engineering phase. We're trying a bunch of stuff out. Maybe we're starting to converge a little bit. I don't know. Can you riff on that at all?

1:10:30Decouple Host: Yeah, I think that's a good way to think about it. And I would say we're well within the bike phase. We are swimming took a while and now we are at the point where there seems to be enough capital and enough knowledge. Like there's yeah, I definitely want to emphasize knowledge and tech development. You'll sometimes see these charts where they're like, oh, funding levels for fusion this decade versus fusion. That's complete BS. You could have pumped as much money as you wanted in the 60s and nothing would have happened because we had to learn. We just had to get better. We had to develop things that we don't have.

1:11:07Decouple Host: And money helps with time, but it's not a one-to-one. So we're now at that point where I think money does really help. And we have a lot of excitement, and we are building a bunch of different things. And we're going to try a ton of ideas, and we're going to learn a bunch, and we're going to make a bunch of failures, just like in the fission times, before we ever get to really trying to converge down and make the economic case. And, you know, it's because it's energy. It's hard because we also you have to try and make the economic fight within arguably the most competitive industry out there. Right.

1:11:45Decouple Host: Like we're not it's not fusion and only fusion. It's fusion and fission and solar and wind and natural gas and whatever the hell else. And so, you know, you have to find your value proposition within that. And you have to find like where, where does this fit? And it's, it's going to be a while. It's going to be, it's going to be a lot of work and a lot of time. And, um, honestly, that's part of why I'm sitting where I'm at now is that's, that sounds like a lot of fun. Like I miss those fission days, right? I'm way too young to have been part of that, but I can try and catch it on fusion.

1:12:16Gerrit Bruhaug: Yeah. I think that's so important. Like in terms of what the product is that will be sold, um, electricity is obviously a goddamn miracle and we bitch about it being expensive. It makes our lives a lot easier. but it's pretty low margin, particularly absent crazy subsidies or outside of energy-only markets where you're able to capture crazy high prices a few days a year or whatever else. It's a challenging place to make money. Ethan Chalif had a great article about whether we could SpaceX nuclear and he was sort of saying, hey, orbital launches is a lot more of a kind of niche, lucrative service than generating electricity.

1:12:51Gerrit Bruhaug: So yeah, that'll be interesting to see how that pans out. I guess, you know, we got to bring it to an end at some point. I did want to ask the question around, you know, China's starting to, you know, well, it's leading the world, but there's no doubt in terms of fission deployment and even in terms of advanced nuclear. You know, we have a lot of startup energy now in the fission world, a lot of prototyping, criticalities, a lot of capital that's floating around. But I would say arguably China's ahead in advanced nuclear in terms of its particularly its high temperature gas reactor program. um where we at in terms of you know the great power competition um in this area of high technology and infusion are the chinese uh you know nipping at our heels like they are in terms of you know uh uv lithography and and chips and ai or um do they have a long way to catch up is there a lot of knowledge um and esoteric knowledge for them to kind of build to get to where we are now in the

1:13:40Decouple Host: west yeah so they're they're definitely going hard like i said they're the number two uh in terms of putting money and even private capital, which is pretty wild to see in China.

1:13:51Decouple Host: But I would say the U.S. specifically maintains a pretty big lead. Fusion is similar to a lot of other big, complicated things in that you can't catch up quickly. You have to kind of build that base. And we've been layering that mud on for decades and decades and decades. And we've invested in a lot of different things. And now we have a lot of a lot of new, you know, these new companies and also new stuff at the labs and things like that. China is definitely catching up. There's a lot of weird like supply chain stuff, too, that comes into this. This is like an interesting side discussion with Fusion of like it's super high tech and it leads into other supply chain questions on laser glass and magnet wires and stuff like that.

1:14:35Decouple Host: So it's kind of like a space program in terms of tech development. Yes. It is very similar and it's similar reason to fund it of like, even if you don't really care what you're going to get out, it's all the secondary stuff that comes from it is amazing. But yeah, no, I mean, China is, I would say they're slightly mean, probably ahead of our European colleagues because they have just really languished. I know Eater's going on in France. Eater's, I'll throw out there right now. I don't think Eater will be the first tokamak to get a burning plasma. I don't even know if Eater will finish. Who knows?

1:15:10Decouple Host: But they're starting to build things up again in Europe. They have a lot of interesting supply chain stuff. But China is just like, they're pouring concrete, man. They're building tokamaks. They're building lasers. They're building all sorts of stuff. And so they're trying to catch up. And I think they will if we, you know, just on like their sheer momentum. But for right now, the U.S. still maintains a pretty good knowledge lead. And then we have a lot of stuff being built, like nearly done. We're the only ones with ignition. We're the only people who can go into a laboratory and look at a self-heating fusion plasma and understand what's going on and learn things from it, which there are new things being learned.

1:16:03Decouple Host: And that's immensely valuable.

1:16:05Gerrit Bruhaug: And you mentioned Commonwealth Fusion Systems. Who are, just in terms of some brand recognition, who are the big names and what are the big claims in terms of, like, you know, the joke 20 years away, almost 20 years away perpetually.

1:16:19Decouple Host: Commonwealth Fusion Systems is the big tokamak company out of MIT. They are building their tokamak. their claim, I believe, is by the end of this decade, they'll get a burning plasma, which will be that self-heating moment for them. And then something about power plants in the next decade. I don't know about any of those power plant claims, but I kind of believe them. I think they're on the burning plasma somewhere, you know, maybe not this decade, but not far into the next one as well. They definitely have the money, right? And they have smart people. There's Exmor Energy, which is where I'm at.

1:16:57Decouple Host: So that's Laser Fusion. We already have some big lasers. We're going for our engineering break-even facility. So the similar to the Commonwealth one on a similar sort of timescale, a little bit behind them. Although you can argue we already know it lights. Pacific Fusion is another big one that's, they're building something in Albuquerque right now. I think they're also on the 2030.

1:17:23Gerrit Bruhaug: And sorry, just to clarify, Commonwealth Fusion is trying to get ignition or they're trying to get to that engineering phase, which is not the prototype phase.

1:17:32Decouple Host: They're trying to go straight to that engineering phase with burning plasma and everything. We'll see about that. But I do think they're going, I think the chance of them getting a self-heating plasma is high. If anyone's going to do it with magnets, it's going to be them. um yeah and then you have Pacific which is doing Z machine stuff um that's another big one very well capitalized down in Albuquerque uh or in Livermore and in Albuquerque and then um the other big name would probably be Helion up in Washington uh and everyone's kind of on these 2030 like early 2030s end of the decade sort of time frames to try and get their initial facilities going um There is a ton of money.

1:18:19Decouple Host: It's been very impressive seeing it from the inside, like how fast things can happen and then not at the national labs where we're just kind of held. We're held up by some weird red tape. But also there is a lot of government support and it's similar to fission. It's like bipartisan. A lot of these crazy timelines, by the way, were set by the DOE and they were set by the Biden DOE who wanted fusion. You know, they want to prototype fusion reactor power plant by like 2035 or something, which is incredibly aggressive for all the reasons we talked about. So, yeah, that's the those are those are like the big names in the US and the Times.

1:18:54Decouple Host: And then we should probably mention that there are some big ones coming out of Germany. There's like two laser fusion companies focused in Marvel and Proxima Fusion just raised like half a billion euros, which I think is the biggest raise in Europe for any startup. So Germany is making a weird bet on fusion, which is interesting to see given their fission history.

1:19:18Gerrit Bruhaug: It's very interesting. And I mean, yeah, I mean, obviously a loaded question, but if you're trying to get cheap power on the grid fast, it seems like spending a billion dollars trying to, you know, reverse the decommissioning work that's happened at the least decommissioned plant would be.

1:19:34Decouple Host: Yeah, yeah. I don't mind the bet on fusion. I think it's got, um, uh, it's an interesting long-term bet. It's you're trying to, I, I fundamentally, I've been thinking about like, you're trying to solve the same problem as the breeder reactor, right? It's the, it's the, it's the infinite fuel supply. Uh, you burn the water, you burn the rocks or you harvest the sun or some combo to quote Alvin Weinberg, um, burning the water definitely will work forever. Uh, you know, you could scale, you could scale fusion to any amount of power and it wouldn't matter because of the resource load on the planet.

1:20:07Decouple Host: Um, but, uh, I would not make that my immediate bet for like the next 10 years. If I was Germany, maybe, maybe, uh, secure your energy supply and, uh, do support a fusion reactor or something.

1:20:22Gerrit Bruhaug: Okay. Last, last point. I promise. Um, just the kind of cultural resonance of, of fusion. I'm not sure if you want to, if you have something you could kind of offer on that, but I mean, talking about Germany as well, right. Where there's, you know, fear and terror about fission, uh, but enthusiasm for fusion. any comments in terms of just kind of popular conceptions the cultural zeitgeist on it like why it captures the imagination of VC investors as well as the public at large yeah I mean it's

1:20:49Decouple Host: been big in science fiction for a very long time and because it was big in science I mean the science the early Manhattan Project scientists all saw it as the next step both for weapons and for energy. They had a lot of concerns with fission early on. Fusion seems to solve a lot of those concerns. But also, as you've talked about on this podcast tour, a lot of those guys were like thinking really, really long term. They weren't thinking the next 20 years. They were thinking, how do we do this for a thousand, ten thousand years? I think, you know, having made the most terrible weapon ever, it got them thinking on scales that were not normal.

1:21:28Decouple Host: and they drove a lot of that thought, right? You know, if Richard Feynman says something to you, you're going to listen. And I think that raw potential is really stuck with people, but also there's been a lot of myth-making that goes with it too. You know, you'll see this in science fiction where the fusion reactor makes zero radiation and you can stand next to it, Mr. Fusion and Back to the Future. but um you know that's not that's not reality i think um it's important to know that reality but i think that that sort of stuff is what's like really captured and resonated with the cult culture of people of like all of the promise of fission without some of the um downside and part of that i think is like because it's not here you can project onto it and so i'm hoping as we get to this as we as we get to this point of fusion becoming more real to whatever extent it does become real but it's it's definitely a lot more real than it ever ever was in the past i'm hoping we don't um make a lot of those same mistakes as well that's like a big thing i try and hammer on my colleagues is you should read the history of like how did fission lose public trust how did how did it stop being this you know in the 50s it was like everything was atomic right that's what people wanted what what did they do wrong um and how do you uh not um you know not not fall into those same traps, those same category errors, those same perpetrating, those same, uh, stretch truths.

1:23:00Gerrit Bruhaug: Okay. Garrett, we'll leave it there. Um, absolutely phenomenal. Um, again, uh, the devil's in the details and it was beautiful to be able to go through those details. And, um, you know, I did a bunch of prep, but more or less I could grasp what you were saying. I think you're just a phenomenal science communicator and really privileged, privileged to have you as a guest on the podcast. We did have a, I mean, it was when the NIF went critical when the NIF had its ignition event. That was the last time we chatted. You were at the National Labs. It was a bit tricky to go through the paperwork to get you back on, but really look forward to having you back again in the near future.

1:23:34Decouple Host: Yeah. And come visit in Denver. We'll show you some big, cool science equipment. Awesome.

1:23:40Gerrit Bruhaug: Awesome. And let's go horseback riding and everyone else should jump on to the decouple sub stack, please just subscribe there. That would be a huge favor to me for my efforts. I would much appreciate that.

1:23:52Decouple Host: Okay. Goodbye, everybody. Today's episode was made

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