The Infinite Monkey Cage - Fusion – Ria Lina, Yasmin Andrew and Howard Wilson

Episode Date: December 3, 2025

Robin Ince and Brian Cox get all fired up, overcome their natural repulsion and come together for this stellar episode on nuclear fusion. They’re joined by plasma physicist Yasmin Andrew, fusion scientist Howard Wilson and comedian Ria Lina to uncover the secrets of star-making here on our planet.Together the panel discovers how the sun fuses atoms to release energy and why misbehaving, jiggling plasma makes this tricky to recreate on Earth. They explore the competing technological approaches — from giant magnets to the world’s biggest lasers — and find out that the hottest place in the solar system is, in fact, in Oxfordshire. Finally, they ask whether fusion could really provide an unlimited source of clean energy, or whether the technology will forever be “just 20 years away”.Producer: Melanie Brown Executive Producer: Alexandra Feachem A BBC Studios Production

Hello, I'm Brian Cox. I'm Robin Ince, and this is the Infinite Mankish Cage, because today we are in Manchester, which is home, in case you don't know, to some of Brian's favourite childhood bus routes. Those of you who are regular listeners will know before Brian started getting involved with the stars, he was an avid bus spotter. So what was your favourite?

You're coming in from Oldham, you've put on all your kind of Robert Smith make-up, perhaps you're going to Jilly's Rock World. No, Clown. Rockwell? Cloud 9 and Berlin, it was. And it was the 24 bus, by the way. They went from Chatterton to Manchester, Piccadilly bus station. What was it about the 24 that really impressed you? It was the bus that went where I wanted to go from. Today we're asking nuclear fusion, when will it be ready? What makes fusion reactors so hard to build when the sun built itself

using only gravity? What are the breakthroughs we're waiting for? To help us understand the challenges, the innovations and the future benefits. We are joined by fusion scientists with an interest in magnetic confinement, a plasma scientist with an interest in spherical tocomac innovations, and a forensic comedian with an interest in viruses and puns. And they are. My name is Howard Wilson. I'm the Director for Science and Technology at UK Industrial Fusion Solutions, which is the organisation that's leading the delivery of Step. Step is the spherical tocomac for energy production. The UK's first fusion pilot plant here on Earth. I started in Fusion in 1988 and about six months later there was the announcement of cold fusion. We were asked to

give an example of what we think is a crazy energy source and I will put cold fusion in that box. I'm Yasmin Andrew and I'm a senior teaching fellow at Imperial College London. I'm plasma physicists and I've been working on a magnetic confinement fusion for the last 30 years. Do you want the unusual energy source? Yeah. So this is more strange was this idea of sending a satellite into space while just above Earth and then making use of the solar wind to drive an electric current and then beaming that electric current

back down to Earth using a laser. I don't know where they've got with that. It's overcomplicated, isn't it? It's very complicated, and the optics aren't up to it, apparently. Is it because when you're looking for finance, if you just say, and lasers, people go, oh, that sounds brilliant, yeah. They don't hear the rest, are they?

They just hear lasers, but more plausible. than Cold and Cold Fusion. Does that mean I'm winning? Hi, I'm Ria Lina. I'm a comedian and lapsed forensic scientist and virologist. And I don't understand why we're even investigating fusion when we already have the technology of hamster wheels that we could do at a size large enough

to put all the children with ADHD in them. And this is our panel. Actually, Howard, I need to ask you first, when you said to your friends, I've just joined Steps, in many ways were they then disappointed. There is a Howard in a boy band, I believe. Yeah, there is. It wasn't me. You're a fantastic conflagration and montage of boy bands with your Steps element, and also you take that element. I thought that was, like, the 12th step program.

And I was waiting for him to come and, like, apologise to all of us. Howard, you mentioned Colfusion there. The first question was to describe what fusion is, but maybe in that context, because many people might not know why cold fusion is, your choice is a ridiculous energy source. Should we start with what fusion is? Yeah, and then we'll start to realize how ridiculous coal fusion is.

So fusion is the process that powers the stars, powers our own star, the sun. You take the light elements, hydrogen, really the light end of the periodic table, or isotopes of hydrogen, heavy forms of hydrogen. And if you push them together close enough such that the nuclei that sit in the middle of the atom get those nuclei to touch each other,

there is a significant probability that they will fuse to create something heavier, a heavier element, and they release energy at the same time. And that's the energy that powers the sun. It's actually the process whereby all of you are made because you start off with the light elements from the big bang, and it's through the fusion process that the heavier elements that were made up from come from.

So it's absolutely fundamental in terms of energy, because it's where the sun gets its energy from, and it's fundamental in terms of our being, where our materials come from. So how do you get two nuclei close enough together? That doesn't sound like a hard thing. Well, it is because they're both positively charged. They don't want to come close together. And so you've got to get enough energy in them to overcome what we call the Coulon

propulsion that like charges repel. That takes a lot of energy. And we tend to do it just by heating it to ridiculous temperatures. So the temperature of the centre of the sun is about 10 million degrees centigrade or so. The sun is a fusion reactor, power plant, but it's not a very efficient one. We have to achieve temperatures at 10 times that temperature to get these nuclei to get close enough together. Why do cold fusion think they're going to get these nuclei to come close enough together at room temperature? And there was an argument that by putting them in a particular metal palladium

and passing the current through them that they would come close enough together to fuse. It didn't sound plausible and it wasn't true. it's because energy from the Palladium again has such a showbiz air there's something about you Jasmine most people when you think of nuclear power probably think of nuclear fission

so what's the difference so fission is the opposite process so to what has just described where you take a very large radioactive nucleus which is unstable and then it will break down into smaller particles and it's the same effect as the binding energy

of the nucleus that's released in that decay and the two small the particles are released with energy. So it's the exact opposite process. So you're saying that you release energy when you stick hydrogen together to make Deuterium or helium, and you release energy when you split uranium up to make lighter elements. So why? So it's down to mass energy equivalent. So in the case of fusion, the sum of the starting nuclei is less than the starting mass. And so that difference in mass is released as energy. And it's the same process in vision. So it's the mass energy equivalence equals mc square which i think is the most famous of physics equations

and people will be familiar with what makes something unstable then are we talking about basically as it increases in size the stability decrease so hydrogen is very simple in terms of its structure and then stable yes exactly so when it becomes very large and then the the forces that are required to keep many of the nuclear particles together and one more energy is needed to create that nuclear so it is inherently unstable. So hydrogen or helium that's used for fusion is opposite, which is one of the reasons that's so difficult because they are stable

and you're almost having to force them to fuse. One of the other differences between the exact opposites of them is if you look at the fission reaction, as long as you put sufficient fissile, heavy material together, like uranium, so you put enough there and start the fission reaction, it is self-sustaining. If you have more than the critical mass, it will run away unless you do things to it.

So in a fusion plant, personally safe, but you, the operator, have to put control rods in to stoke up these neutrons to stop the reaction happening. Just say you said fusion plant. Fission plant, sorry. Again, this is got your classic music hall routine, fission, fusion, fusion, fusion. How do you feel real about?

Because, you know, your forensic science you were fascinated by, viruses you were fascinated by, you know, my mind does get very easily bamboozled by physics because the scale that you're dealing on is so kind of fascinating to try and create a picture of it. How do you generally, as you hear these ideas bouncing around? I have so many questions right now. Question number one, if it needs that much heat in order to release energy, you're using energy to create energy, it feels inefficient and don't understand why we're heading towards fusion. The amount of heat that we're using to fuse two hydrogen atoms together

is still less than what it would release. That's incredible. It's a key question. So we have to create conditions such that you put sufficient heat into the plasma that it will start to burn. This is what we call it burning plasma. So it will be self-sustaining. It will no longer require external heating. And in fact, it will start to produce net heat. Until it runs out of hydrogen atoms. And then it will just be helium plasma.

You keep supplying the hydrogen as it's running. You're trying to get the helium out as the... So you're like a drug dealer. Just like, come on, have some more hydrogen. Come on. Yeah. And it just sits there, pushing it together. You need to fuel it for as long as you want it to burn.

It's essentially the same as the sun, right? The sun is a self-sustaining fusion reaction. But we've all been told that the sun's going to run out at some point. It will. Right, so it isn't. Five billion years. You say that, but it'll come around in no time. I know there was a very famous story of Patrick Moore,

where he said that he was giving a lecture and he said that. He said five billion years, the sun will run out of fuel it'll swell up it may engulf the earth and someone did say did you say five million or five billion i've got you know i and he did say it doesn't it doesn't matter but it is that thing about time isn't it that you go the first billion years went really slow but my god the last four billion just rates past that's what happens as you get older don't you time means something different i mean that was my second question i mean if the sun is just constantly creating helium if it could speak.

Would it sound like this the whole time like it ate out of a balloon? See, I wanted you to do that voice. I wanted you to start with that you want some more hydrogen and go oh you want some more helium. I was hoping that was where that was going to go and then we would go across the whole periodic table and then I think Deuterion probably kills us, I don't know, but yeah.

The first question... Until we get to America. Oh my God, aren't we amazing. We should say first of all it's not hydrogen that we use as a fuel in the reactors that we We could do. You could in principle, but the conditions you need are even more extreme if you use pure hydrogen. So we use two heavy forms of hydrogen.

One is called Deuterium, which sounds fancy, but actually there's loads of it. It's everywhere. One in every 6,000 hydrogens is in fact Deuterium. And if you think about all the water in the world, all the H2O in the world, one in six thousand of those Hs is actually a D. So there's loads of Deuterium. Absolutely ram full of it. Yeah. What a great issue.

so. And then the other one we use is tritium. It's not stable and it will decay, but 12 years. It's got a half-life of about 12 years, which means if you have a jar of tritium, go away for 12 years, come back again, half of it's gone, half it's decayed into something else. So tritium is really rare. There are sources of it, but it does mean we have to manufacture it within the plant and we may come back to that later. But that's the reaction that we use, Deuterium and Tritium, because although it's still hard. It's not easy to get something to 200 million degrees and hold it here on Earth. We all know that, don't we?

So it's not an easy thing to do, but is the easiest fusion reaction to do. And it gives you helium, as we've been discussing, and it throws out a neutron as well. It's the energy of the neutron that throws out that we will capture basically boil water and drives turbines for... So that's the self

sustaining reaction? It's the helium going back in. Yeah. So the helium has one fifth of the fusion energy. The neutron has four-fifths of the fusion energy. the helium stays inside the Deuterium and Tritium and gives up its energy to the Deuterium and Tritium. So once you've got it going, the helium that's produced keeps it going. Just to double check, this is all with consent, right?

We're not just forcing these atoms together against their will. It is against their will, isn't it? We are forcing them together against their will. I don't know if this is going to pass. So, Yasmin, so Fusion, probably most people have heard of it. There's almost a joke, isn't there? It's always 20 years away. But it is often presented as the Holy Grail of energy production.

So I suppose that there are two questions there, which is, why does it always appear to be decades away? And why is it the Holy Grail? So I think it is limitless sort of energy. And so that's why it's the Holy Grail. So if it's achieved and it's controlled and it can be hooked up to the grid, it has vast potential. For society, for electricity generation, for many of human. Humanities problems in terms of inequalities for electricity access, and it doesn't require a lot of fuel. Part of the fuel that we need is very abundant, easily accessible.

Personally, I think it's been underfunded for many, many years. It wasn't fashionable. So they had fission. There was no reason to fund fusion research. And so, you know, we've been doing that research for a long time. I think for quite some time it wasn't very much in the spotlight. It has had decades of funding, but at a relatively low level. I would say. And so I think when you compare the amount of funding or the efforts that were put into

developing fission when that energy source was needed, it's not really comparable. So you can start to see it now. The focus is definitely shifting. I think there is an awareness that fusion is needed. The funding of the research has started to change. And so now it's becoming much more serious. And so now if the efforts are there and we're able to grow the community and we have many strands of fusion research, I think there is hope that it can be developed and on the grid and in a controlled way. So is that basically that because we're now seeing the implications of climate change, now it's actually becoming a reality? Is that what has finally kind of sped it up in terms of research? I think this recognition that oil and gas will run out. I'm not sure if it's actually

embedded in concerns about climate change. I mean, for me, obviously, that's a huge one and That's, again, another appeal for fusion. Fossil fuels are not never-ending, and a replacement is needed. We need a continuous source of energy that renewables and sustainable energy is very important, but I don't think it's going to fill the gap that fission will until fusion is ready. And when fusion is ready, it looks like it would take the place of, for example, fission which has its own problems. And that's in about 20 years' time, is that right?

Yeah. Really, you had a question? No, I was just going to apologize for the lack of funding. I think we've been spending it all this time on vaccine research, but as we all know, that's come to nothing, so I'm really sorry about that. Have you been taking your paracetamol again? No, because I'm not pregnant.

So can I add a perspective on this? I think fusion is difficult, and fusion is expensive. The research associated with is expensive, and so there's been a big view that actually fusion will be ready when we need it. And I think a large number of politicians and the general public understand that we do need it for climate change. And we do need it for energy security. And that's something that's been particularly important and risen in priority over the last four or five years, for example. And so people now go, yes, we do need it. And you'll have seen over the last five, six years,

as people have gone, yes, we need it. You'll see a lot more private investment going in, billions and billions of pounds. And that funding is now starting to accelerate the process. and we are starting to see fusion power plants on the horizon in the next decade or so, at least in a prototype sense that demonstrates that it's feasible. How many different technologies are there? Because essentially the point is you have to stick some deuterium and tritium together, so hydrogen, basically.

How many different ways are there of doing that? There are hundreds, but actually they can be categorised as two. One is inertial confinement fusion. one is magnetic confinement fusion they're both trying to do the same thing to do fusion you need a sufficiently high density you need actually a certain temperature there's 200 million degrees

and you need to be able to confine your fuel for long enough you need a good enough system to be able to hold the heat in sufficiently well sufficiently insulating system and so you have this so-called triple product of density temperature and confinement time inertial fusion they take a small pellets of deuterium and tritium about a millimeter or so in diameter and they coat it with something

something heavy typically and they put it in the size of a big chamber we're not that much small in this room actually and they focus a large number of lasers like 200 lasers or so on this poor little pellet 200 of the world's biggest lasers and that basically burns off that coating

from the Deuterium and Tritium and as it blasts away it pushes on the Deuterium and Tritium compresses it to really high densities like a thousand times solid density It's like taking a brick that a building is made out of and just squeezing it down to a Lego brick. So you get really, really high density. You get the temperature as you compress it,

but it has really short confinement time because there's nothing holding it there. The only confinement time is associated with the inertia of the fuel, so it's like billions of a second. But that product of density and temperature can in principle get you to fusion power. And they demonstrated it once with one shot a day kind of thing. They would need to do that 10 times a second

in order to deliver fusion power and much, much more cheaply than they're doing at the moment. So that's inertial fusion, and then magnetic fusion uses the fact that if you heat something to 200 million degrees, it doesn't look like the matter in this room, it looks like something called a plasma. So if you take water, for example, you know the three states of matter that we're familiar with solid liquid gas. Take water, solid state is ice, heat it, it melts, you get water. Heat that, it vaporizes, you get seam. Now keep heating it. Your water, your H2O bonds split apart, because you bring so much energy into it, your H2s split into individual atoms.

If you keep heating it, it gets so energetic that the electrons surrounding the nucleus effectively boil off that central nucleus. And you're left with this big ionized gas of positively charged nuclei and negatively charged electrons. The whole thing is still neutral because you haven't made any charge, but now you've got charged particles in there. And that charged particle gas behaves very differently to the gas. that we have in this room. And that's a plasma. It's fascinating. I spent my life doing it. But it's what we have to study in fusion

to make fusion happen. Now, because the plasma has charged particles, we can hold onto it in magnetic fields. It's lower density, much longer confinement times, and the temperature's the same in both of them. And magnetic confinement is holding that plasma for much longer time scales to create the fusion process.

Now, Yasmin, you're... So your expertise, a plasma physicist, initially. So the problems we have build in fusion reactors or the confinement reactors are essentially associated with controlling that gas, which would seem, as you described it, how it to be quite easy to stick it in a magnetic bottle or something and it just sits there. So Howard's described that really nicely, so how you create the plasma. So essentially you need some way to ionise the gas. And one that people are familiar with would be the neon light. So you have the different colours of neon lights. And those are plasmas. Essentially,

they're low temperature plasmas and they will have created those by running an electric current through the gas and that's enough to ionise it. For fusion we need to heat that plasma up to the very high temperatures needed to actually bring the positive nuclei close together. So then you're going into high temperature plasmas and that's where the temperatures that are needed for fusion to happen you couldn't have such a hot plasma in contact with a wall so you could put a magnetic field in it and then the plasmas because they're charged particles in the presence of a magnetic field they start to do really interesting things and they spiral around the magnetic fields and it essentially traps them so that's a great way of moving the plasma away from the walls

of the whatever you're containing it in so then you're reducing the problem of melting the walls the vessel but you also need to keep the particles in the same place for long enough for fusion to happen And so if you're constantly leaking particles, it's just much less likelihood of fusion taking place. So they solve that problem by taking our magnetic fields and basically joining them up at the end. So you have this infinite way around a donut-shaped vessel. So you're reducing those end losses. But because you now have what we call it a troyal geometry, so you have this donut-like geometry, it causes other losses outwards towards a vessel.

So again, the confinement is not perfect. And then the really important thing is we have a very high temperature gradient between the middle of the plasma, where we're trying to get the temperatures high enough for fusion to happen. So if you imagine we've got tens of millions of degrees at the center of the plasma in this donut, and then the walls of the, on jet, I think, for example, was a big experiment near Oxford.

The walls were held at 300 degrees centigrade. So there's a massive temperature gradient between the middle of the plasma. and the edge of the plasma. And what's the distance, though, that we're talking about? And that was three meters. Three meters. So whenever you have these huge temperature gradients,

I mean, you end up with something called turbulence. And turbulence introduces plasma losses. So, again, it influences confinement. Can I recommend you maybe need to watch more Star Trek because they're always getting breaches in the plasma manifold? And they seem to manage it. We'll talk after a. We'll have a look.

I mean, we should look at Voyager. They got all the way home from the Delta Quadrant, all right? it's not it wasn't a spore drive or something it wasn't they didn't use it oh oh i'm in pain i'm in pain i'm not familiar i'm not familiar with this yeah no that was discovery that was we don't talk about that we don't know what was the spoor drive then the the sport drive was was a ship that we don't talk about that that transported along mythelial networks um and then ended up very far in the future, even though it's all in the future, but even further in the future, with Spock's sister on it, who now he then never mentioned again, because he didn't

know he had her when he first started. But there's a lot of show business, because each time there's a little moment in this conversation, so we started off with steps, then we had palladium, then you bring in neon, and then I notice when you say particle loss, you do jazz hands. So I feel that it's the most show-busy physics episode we've. done yet, I reckon. Howard, getting back to the point. It sounds

like at least a simple problem to state, which is we'd like to create a plasma, if that's the kind of fusion we're talking about, and we'd like to confine it, we'd like to hold it long enough, essentially. So why can't we just solve it? We know that fusion works

because we see the sun doing it all the time. We know the conditions we have to achieve to make fusion work. What we have been struggling with over the decades, is how to achieve those conditions. And before the fusion process takes over, one has to put in enough energy to spark it up. That churns the plasma up, and that generates this turbulence.

Now, the turbulence is a really complex thing. You'll have pictures in your head about turbulence at the bottom of waterfall, for example, and that's already pretty difficult. If you just look at all the different structures that appear in the bottom of a waterfall, big eddies, small eddies, you can imagine trying to understand that is a very difficult thing. We can understand that. but a plasma turbulence is different again

because it has that physics so it does have those sorts of churning away the same as water would have but in a plasma remember the particles are charged and we are holding onto those charges with a magnetic field and if those charged particles start jiggling around as they would with turbulence your charged particle

jiggles around if you move two charges relative to each other you create an electric field so jiggling charged particles around jiggles your electric field you can also jiggle the magnetic field and those jiggling electric fields and a jiggling magnetic fields feed back on the particles. And they feed back on them in a very special way. And the best way to think about this is to go to the beach and watch a surfer.

And if you watch a surfer, and if the surfer does not paddle, the wave will just go under them and they'll bob up and down. They're not tapping any of the energy of the wave at all. If a surfer paddles to match their speed with the wave, what we call a resonance, the wave will pick the surfer up and take them into shore, and the surfer is tapping the energy. of the wave or the particle is a surfer is tapping the energy of the wave those resonances are happening all the time in plasma physics and that interaction between energy in the wave and energy

in the particles is happening all the time from all of these different resonances but to understand those resonances you not only have to understand where all the particles are which is what you have to do for water you also have to understand what their velocities are which direction they're going in how fast they're going and so there's a whole it's another three dimensions there it becomes a six dimensional problem, there isn't a computer in the world that can solve that problem. And so we have a whole bunch of very clever theoretical models which reduce the dimensionality of that to make them tractable on today's computers. And so we are starting to be able to predict what the turbulence will be and what the consequences

of that turbulence are for the heat and particles leaking out through the magnetic field and starting to be able to design our tocomax, as these machines are called, or stellarators, you might think as well. We can start to understand how best to design those so we can minimize that turbulence. I will make a not so bold statement if it wasn't for plasma turbulence. Fusion would have been working decades ago. Up to the point that we are now, it's been because it's really difficult to simulate, so we're just about managing to do it now. So it's had to be experimental. So maybe you could talk a bit about JET, which was a world

leading experiment in Oxford. There's a really cool fact about JET, actually. Jet reaches these temperatures. We can do 200 million degrees. That is the hottest place in the solar system in Oxfordshire. So that's a really cool statement. But yeah, so how do you do an experiment in something that's 200 degrees centigrade? How do you see what's inside those plasmas? And we use lasers. You fire the laser in and temperature, the temperature of a gas is how much your particles are jiggling about. If you heat it up, the particles jiggle around more and more and more. So now if you fire a laser into your plasma and it hits a jiggling particle, it will

scatter off that particle. And so you fire your light in at a very fixed frequency. When you measure it coming out, you find there's a width of frequencies that come out, and that width of frequencies tells you about temperature. But it's far from easy to do the experiments. It's far from easy to do the simulations.

We need to do both and combine the two. So Jets, you said it's about, what, three metres? Yes, three metres, major radius. So Jets stands for the It started as the Joint European Taurus, and ETA is the internationally, originally was called the International Thermonuclear Experimental. Was it reactor? They used the word reactor. It's not a reactor, it's an experiment. And that, I think, it's five meters. Six. Okay.

It's very big, though. I've seen it, so it's a theatre-sized thing. It's a big object. So we have known for a long time that, for the magnet technology that was available, that this much larger machine was required to reach the confinement. So the plasma is contained in something called a vacuum vessel. So it's a metal donut-shaped vessel. And it is usually built in eight different parts. And if they're being built by different people, they have to fit. And the tolerances are very, very small.

So even just a few millimeters out on the welding, I think, can cause problems that they don't perfectly fit because you have to create a very high vacuum in there. There can't be any leaking. Can I go back a step just going back to turbulence? First of all you said it's a six-dimensional problem. So what exactly are the six dimensions? You've got the three dimensions that we're living in here

and then the other three dimensions that you have to... So length, width, depth? Yeah, yeah. Of the confinement or of the of the plasma? Of the plasma. The same as in this room but then the other one we're still pretty familiar with it's just the velocity dimensions. So you have to know which ways the particles are going. So there's another three dimensions about

where you can move. So you can I say I'm here at any one position at any one time and give a spatial dimension about where you are now so we'll give your coordinates in this room but now you might be moving in a certain direction and you could be moving that way, that way or that way and that's another three dimensions. It's just three more pieces of information

that we need to know about your position not just where you are, it's what direction are you moving in as well. And that's six? That's six. Three, the three, your three spatial. Is that six to anyone else in the room or is that like the first three change?

article. So this is what is determining the turbulence that you're trying to research and resolve. And am I right that you said that the larger the Taurus, the less problematic the turbulence is? No, so the plasma becomes large enough that the confinement is better. There's greater likelihood of

fusion. You should say it's not obvious is it that if you go because people might be thinking it should be obvious. You go bigger, it's easier. But that was a difficult problem right. It took a while to realize that didn't that? Right. So there's been a lot of what we call cross-machine scaling

are looking at the effect of changing the size of the machine. So that is an empirical scaling which has shown that the confinement improves as some plasma size gets big. It's purely experimental. The new technology

that will make a big difference is the high temperature supercontactivity for the coils. So the magnetic fields we can apply to these experiments, it was always limited by the use of copper coils. So with the advent of high-temperature superconducting coils is now possible to have much higher

magnetic fields on Tokomax, and so that's a route to improving confinement. So that's a fairly recent development. They started work on that in the late 80s, but I think we've only seen actual application of it, really in the last 10 years. You know what I find really interesting about this is that it's an example, and there aren't many examples, I think, of engineering that's so difficult that we have to learn so many things that it takes decades as you said this magnet technology

we discover it in the 80s or the properties of these materials but it takes 30 years to implement I suppose that there's a natural question is why is that you gave one example which was just the amount we invest in it

but I think could you speak on how difficult these technologies are, and there are quite a lot of them that you need to build one of these reactors. If you think about taking something right from first discovery, right through to final delivery, people are really excited about the discovery thing because you're pushing the frontier of human knowledge. You get a lot of investment and a lot of your brightest minds looking at that. Then go to the other end of the scale where you're actually bringing it to the market. There's also a lot of interest to learn that. It's usually different people.

It's usually people who are interested in making money because it's sufficiently developed. And so that also attracts a lot of money and it attracts a lot of bright minds. That bit between is everything called the Valley of Death because you still have to keep investing and you still have to get clever people working on it to take it from the lab through to the final marketplace. And it's a little bit of a thankless task because you don't get big high-profile papers,

you don't get to sit on the stage with Brian Cox. And so it can fail because you can run out. out of interest, you can run out of resource. And so that is what takes a lot of the time, is taking it from an idea to a commercially viable product. And this is where fusion now is. We have done it in the lab, they're big labs, and we are now trying to commercialize it. You can't reproduce the conditions in a fusion reactor until you've got a fusion reactor. So we are going to be relying on simulations, and we're going to have to use those simulations to be able to predict what's happening. But we need to be confidence those simulations are right.

So you need to be able to test it against experiments, and the skill of the scientist is designing that experiment to test your theory. So what I think that we need to do is to not just think about doing simulations and doing experiments and occasionally comparing them to validate them, but actually do the whole thing together, integrate the two things together, the simulation capability, the virtual world, with the real experimental world. So you give you a capability that will be able to drive you through this valley of death faster. I have to pick up on Howard's point. I think I agree with him 100%. As an experimentalist, I've always enjoyed working with theorists because what's interesting for me is taking a really cool idea, a really cool theory.

Can we test this? Can I design an experiment that will look into this and see how valid it is? Does it explain what we're seeing? And I thought it was very interesting what Howard said, which is one of the challenges in order to do experiments on plasmas at scale, you have to build the thing you want to do the experiments to tell you how to build. It's the only way to do the experiment is to build a fusion reactor. Is that one of the problems, I guess?

It's one of the challenges, yeah, yeah, because you can't reproduce the conditions on Earth. And it's not just about the plasma. It's about the neutrons that are produced as well. Rhea, how's your mind been through this conversation? Well, actually, I'm going to be honest with you, I've been thinking about the turbulence issue, and I was thinking about water slides. Have you just tried tilting the torus?

You know, think about it. When you're in a water park and you're all sitting in your own little rubber rings and it's just like that river thing and you go through and it's really slow and you all bump into each other and it's just a bit rubbish, right? But then you go and you take your rubber ring up to the top of the slide and that's really good because gravity's whooshing you down and all the water's going in the same direction. So I'm figuring that that's your issue is that your torus is flat and you just need to tilt it on an angle so that we get some gravity.

Do you know what I mean? Like just get that whoosh going. Yeah, I think that. I agree, yeah. I think we are seeing the beginning of the movie about when you won the Nobel Prize in 2037, and you're still working on that thing. No, no, how it's theoretical.

It's a really good point. So that wash that you're talking about where it's going around, the donut exists, and it's really important to the... I'll take the job. It's fine. I'll hope you finish it. We'll get it go.

You get me on board. We'll do this by 2033. telling you're saying that's correct so that wush does suppress the turbulence it tears the turbos apart I am wasted in comedy

someone's just want a free pass to Thorpe Park haven't they for a lifetime just very quick because we are at the end but I just like to finish by so what is the future that you envisage so let's say that these go-to-plan and ITER works and Step works. So by, let's say, 2050, let's say, so 25 years time, how much of the energy that we use on the grid would you envision we'd be coming from

fusion? So I think 2050 we will see step operating. It will start operating in 2040 and during that decade we will put net power onto the grid. But not in a commercial sense. We'll put a few megawatts of power onto the grid. And that's in Oxford. No, that's in North Nottinghamshire, West Burton, which is where I'm based, which is a disused coal-fired power station. So I look outside my window and there's the big cooling towers from the coal pipe, and they're pretty cool. I thought they were cold cooling towers because they were cooling the water, but they're cool. So they will come down in about a year or so's time, two years' time, and they will be replaced by a step fusion. So that will be putting electricity onto the grid? That will just demonstrate that we

can do it and then also during the 2040s we'll be designing that first fleet of commercial plants and those commercial plants should come online if you're really ambitious and really went for it really pushed for it in the 2050s and then our power it's a large fraction of the power no it's not going to be large it'll grow up slowly it will take you of the order of 10 years to build one just as it does with a fission plant when you've got them the fuel is seawater basically the fuel is seawater and lithium so we didn't talk about the breeding but you get the tritium you get the tritium by reacting the neutron that comes flying out of the reaction, you react it with lithium,

and that lithium produces the tritium that goes back into the fusion plant. So your raw elements, a deuterium that you get out of water, and lithium that you get out to the ground, and you'll all have in your pockets now in your mobile phone batteries, your laptop batteries.

And there's a really nice little picture that we give about how much fuel there is in the world, and the picture that's often used is if you take all the deuterium that's in a bath full of seawater, and if you take the lithium that's in maybe one, maybe two laptop batteries, and you do fusion with it instead of having a bath and instead of using your laptop, that will give you your full lifetimes electricity needs,

the lithium in two laptop batteries and the Deuterium in a bath full of seawater. So that's why we want to do it. That's why we want to do it. It's a smellier world, but a happier one. So, Yasmin, so would you concur with those times? Absolutely. I mean, I think it is coming. I think we have real evidence. There's been huge breakthroughs actually over the last five years.

So we had the big results actually from the National Ignition Facility in Lawrence Livermore Lab in California, where they had net fusion. And then we had a major result from Jets and the joint European tourists in the last few years where they were able to show significant energy from fusion reactions over five, six seconds. So in terms of demonstration of the principle, and they did that twice, actually, in their last couple of years. So there's been real demonstration of the principles of fusion, and there's been massive. change, I think, overcoming many of the challenges. We've demonstrated it, and the plasma is also running longer than ever before.

And, Ria, does it frustrate you? Because it often frustrates me, when you hear the numbers, so you say, well, essentially some seawater and some lithium, and you power your whole life, you can see cities are powered with not much of this stuff. Does it frustrate you that we don't invest and we don't move as fast as we could do? No, I think it's a bigger question than that, isn't it? Funding, it's all about education. We don't fund it because we don't know about it.

We don't know to ask for it. We don't know to say, actually, can you stop spending money on, I don't know, fantasy football, and can we please start funding fusion? That's the problem, is that, you know, we're not even really taught about fusion in school very much. We're taught about fission, definitely. But we're not taught it at this level to say, and by the way, laptop and a bath. and we'll get you another laptop. There's a lot that needs funding,

and there aren't a lot of people that understand that that's really where the money should go or believe that that's where the money should go, and that's a much bigger problem than this show. Is that next episode, is all of economics? No, the next episode is just a recording of the sounds you make as you go down different water slides.

It's just a whole... It's going to be great fun. We asked the audience questions as well. We ask them, what do you think is the greatest untapped energy source in the world? Ria, where have you got? I have three that go together. Here we go.

Underground water, because springs can only get better. Excellent, yep. Caper tossing at the Highland Games, because flings can only get better. Well done, everyone again. And deep-sea thermal vents, because things can only get wetter. Yeah. Well, tidal energy, because the moon should earn its keep. the crackling electric tension

of every man looking straight ahead in a crowded urinal I think we'll end on that one thank you so much to our fantastic panel Yasman Andrews, Howard Wilson and Ria Lina next week our episode we're going to be gazing up at the sky

and finding elephants or maybe dogs or maybe the wispy face of Brian Cox formed out of the vapour of the nimbostratus cloud above us. Well, basically, we're going to be talking about clouds. And what we see in clouds, but probably not that. But there is currently statistics to suggest that you are now seen more in water vapor patterns than Jesus.

I think that's entirely appropriate. Good night. Good night. Monkey Cade, without your trouser in the infinite monkey cage. You're now nice again. Hi, I'm Phil Wang, and this is a podcast to podcast trailer for a different podcast than this podcast that you've listened to or are going to listen to. But nonetheless, I'm talking about another podcast that you should also definitely listen to.

The podcast I'm talking about is Comedy of the Week, which takes choice episodes from BBC sitcom, sketch shows, podcasts, and panel shows, including my own show, unspeakable, and puts them all into one podcast. Maybe I'll trail this podcast on that podcast. Who's to say? I'll do what I like. Listen to Comedy of the Week now on BBC Sounds. Podcast.