Cleaning Up Episode 119 Edited Highlights - Dr Aneeqa Khan

Michael Liebreich Aneeqa, fusion has been in the news because of the breakthrough at the Lawrence Livermore Laboratory at the end of last year. How momentous was that breakthrough?

Aneeqa Khan So, for fusion science, that’s huge, that's never been done before. We've never had a reaction where more energy is put into the reaction than we get out. In terms of having fusion as a source of energy or a source of electricity, we're still a very long way off, because that energy out doesn't take into account all the energy the lasers took, for example, to heat up the reaction that occurred there. So, although there was a net energy gain of the reaction itself, engineering-wise, there wasn't an energy gain. So, a long way to go in terms of fusion as an electricity source.

ML That laser was two megajoules of laser, and it produced three megajoules out. So, that's incredible. But the laser took 300 megajoules to create. So, it's 100x improvement needed overall, just to break even; not to produce net electricity, but just to keep the whole thing going.

AK I mean, for inertial confinement fusion, I guess if we look at that one experiment, that's what the data is telling us, But it's not the only type of fusion confinement that is available. There’s also magnetically-confined fusion, which uses magnets to hold the fusion reaction in place. Other techniques haven't achieved net energy gain yet, but I believe that they will do sooner rather than later. But for sure there's a huge area needed for improving the efficiency all around, whether we're using lasers or using magnets to confine the fusion reaction.

ML Can we try and break down the nuclear reaction that you're trying to spur?

AK Absolutely. So, we start off with two nuclei that we want to fuse together. At the moment, typically, the most common combination is using deuterium and tritium. Typically, to do that, in a magnetically confined fusion device, we need to have them ten times hotter than the centre of the Sun. So, we're talking about temperatures of 150 million degrees Kelvin, in the centre of a plasma. So, this super-heated gas causes your atoms to split up into your nuclei, and then your electrons as well. You can use magnets to confine the reaction in a doughnut-shaped device, which is called a tokamak. So, you have this doughnut-shaped device, you have a plasma running around on the inside, and it's confined. And the idea is that in the future, when you generate the heat energy, you can extract that from the device and use it to generate electricity or other applications that require high heat. The tokamak is not the only design, there's also, in magnetically confined fusion, something called a stellarator, which kind of looks like Salvador Dali drew a donut.

ML Let’s take a second to talk about what is heat load, for people who are not of an engineering or physics background?

AK So, the plasma will generate heat that's going to impact energy on a certain area in your reactors, so that's the heat load that we're talking about. In tokamaks, you've got super-cooled superconductors that are helping generate magnetic fields, which are cooled to about four Kelvin, so almost absolute zero. And then you've got the centre of the plasma which is 150 million degrees. In the space of a couple of metres, you're going from almost absolute zero to ten times hotter than the centre of the Sun. And there's nowhere else in the universe with such an intense temperature gradient. So, I think that really sums up the extreme challenges of the fusion reactor.

ML Let's move on if we could just to some of the engineering challenges. Is there a parallel effort on engineering? Or is it more, well, hang on a second, we're still 1% of the way towards actually producing enough heat, so that it's not even worry about that?

AK So it's early stages, but it is happening, people are doing research into the infrastructure we need to extract the heat or the energy out, whether it's for electricity or other applications as well. So, Kyoto Fusioneering, they're looking into that, they're trying to demonstrate what infrastructure we would need. And certainly, the hope is that in the next few decades, industry will be leading the way on fusion innovation, not researchers; it will be an industry led endeavour, I believe, as we go forward.

ML Is the goal to run continuously? Or will it always be in pulses?

AK People are trying to see how we can run it for longer and longer. There may be technologies that develop it to run longer; stellarators already can inherently by their design. I don't think it's a problem if it does run in pulses, as long as we can store the energy that's produced in some way. So, whether it's with molten salt or another kind of energy storage facility. So, it may be that it runs, it generates this heat, it's stored with molten salt, and then you can use it kind of continuously.

ML How far are these things from the market, from actually becoming commercial? I look at it with knowledge of all of the different things you need between the lab and actually starting to feed electricity reliably into a grid at scale.

AK Yes, I definitely think it's a long-term solution, we're not going to have fusion electricity on the grid tomorrow. I think we will in the second half of this century. After 2050 or so, I think we will be able to have fusion electricity on the grid. In the short term, we need to be using traditional nuclear and some of the other renewables that you've mentioned, whether it's wind, whether it's solar. We need to be throwing everything we can basically at the climate catastrophe.

ML But you've got these startups, who are all promising that they're going to be able to produce a replicatable design before the end of this decade…

AK In terms of having a fusion reactor similar to JET and ITER, it would be the later half of the century before we could have them actually contributing to our net energy baseline. I think everyone will be very happy if someone is able to do it quicker. There are so many different designs, and I think as a community, we shouldn't be scared of failure. It's like any big race towards something, there'll be some that do it, and some that don't. And as long as someone does it, I think none of us really care. Real progress requires a lot of effort and long term planning and work. And I think we do need to look at the long term.

ML We hear all about the actual fusion startups; what we don't hear about so much is the way that there's this accompanying explosion of knowledge and potential spinouts.

AK Absolutely, there's so much crossover with other industries and applications. Anything with high temperatures has so much overlap with aerospace, or other kind of high heat applications. If we look at robotics, that's another area; anywhere where you need remote handling, or places that are very difficult to get to, there's been huge advances in robotics in fusion, and I think that's definitely transferred. Same with the high temperature superconductors. Digital engineering is another big one taking a big role in fusion and again, very transferable to other industries as well.