New Energy Record Set By Fusion Reactor

8:50 minutes

The promise of a human-made, sustained, controlled nuclear fusion reaction has always seemed to be “just a few decades away.” But now recent results from JET, the Joint European Torus experiment, have researchers hopeful that practical fusion may indeed be possible as soon as 2035.   

In the experiment, a high-temperature plasma made of equal parts deuterium and tritium was confined in a magnetic containment vessel known as a tokamak. The run produced 59 megajoules of energy over a fusion “pulse” of five seconds, considerably longer than previous attempts. While the experiment did not produce more energy than it took to produce the extreme conditions needed to induce fusion, researchers took the run as a proof of concept that an upcoming reactor called ITER should be successful.

Alain Bécoulet, head of the engineering domain for the ITER project and author of the upcoming book Star Power: ITER and the International Quest for Fusion Energy joins Ira to discuss the recent advance at JET and the prospects for producing a sustained, controlled nuclear fusion reaction—what Bécoulet calls mastering a small piece of the sun. 

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Segment Guests

Alain Bécoulet

Alain Bécoulet is head of the ITER Engineering Domain at ITER in France, and author of the book Star Power: ITER and the International Quest for Fusion Energy (MIT Press.)

Segment Transcript

IRA FLATOW: This is Science Friday. I’m Ira Flatow. Last week, we mentioned in passing a major advance in fusion research in Europe, a test run at an experimental reactor called JET that smashed previous records for energy output. This week, we have time to talk about it in depth.

What was the breakthrough? What does it mean for future attempts to achieve sustained nuclear fusion, the holy grail of clean nuclear energy production? Joining me now is Alain Bécoulet. He’s head of the engineering domain at ITER, the next-generation fusion test facility under development in France. He’s also the author of the upcoming book Star Power– ITER and the International Quest for Fusion Energy, coming soon from MIT Press. Welcome to Science Friday.

ALAIN BECOULET: Thank you so much.

IRA FLATOW: Can you tell us what actually happened at JET? Why are people so excited?

ALAIN BECOULET: So what happened at JET that was announced last week, but in fact that happened at the end of last year, is effectively a breakthrough in one of the performance indicators of a fusion device, namely the amount of fusion power that is produced for a given duration. 20 years ago or so, JET had already achieved an important step in this nuclear reaction, let’s say, performance. Namely, JET has achieved something like 16 megawatts of fusion generated by these reactions out of 20 megawatts that were injected in order to create the conditions for this reaction. So basically, getting as much power from the nuclear reaction as you need to heat and to create the conditions for these reactions.

But this was a very short pulse. So JET has pursued its research and development for the years after this record and constantly improved the situation. And last week, they reported the fact that now, we as a community, they as a machine, are able to create something like 10, 11 megawatts of fusion for five seconds out of something like 30, 40 megawatts that are injected in order to create the conditions.

So the pure performance is slightly lower, but the duration is extremely important, because this record means that effectively, it works. Effectively, we can create and maintain these conditions. Of course, the machine JET is at the end of what it can do with all the technologies that are presented yet. So the next step will be realized by the ITER machine that is under construction, but that will be equipped with all the technologies in order to further maintain and develop this kind of performance.

IRA FLATOW: Why did it stop after five seconds?

ALAIN BECOULET: So the reason why JET experiment stopped after five seconds is because this device that was built and created 40 years ago or so is not or was not equipped with the proper technologies to sustain longer. You can imagine that you have this very large heat, this very large energy, that is created, and that you have to withstand it. It is exhausted from the plasma outside to the machine.

And if the machine is not simply properly designed to be actively cooled and to deal with this extraction of power, then you can only rely on a very short time. And then after that you have to stop, simply. ITER is designed to create these kind of conditions for much, much longer. So it’s a matter of, really, design of the machine.

IRA FLATOW: And so we have to wait for a bigger machine, then.

ALAIN BECOULET: Yes. Well, this bigger machine is under construction, as you said. This next-step machine is called ITER. It’s 10 times bigger than JET. It’s really at the size of now producing 10 times more power than the power that is used to create the conditions for fusion. So it’s an amplifier of power.

And the goal that is given to ITER will be to amplify this power by a factor of 10 on durations that now, with the proper technologies, will reach quarters of an hour, one hour, these kind of durations, or even much longer durations. And also, demonstrating that we have all the technologies to operate, to manipulate, to maintain these kind of conditions. So it’s the pre-reactor. In fact, ITER will be the very last step before being able to build, really, reactors that will then generate electricity and couple to the network.

IRA FLATOW: You know, the joke has been for many decades that no matter when you ask, practical fusion is always 30 years away, right?

ALAIN BECOULET: Yes, right. Or 50.


ALAIN BECOULET: We went down from 50 to 30, so it’s getting better.

IRA FLATOW: Well, when might we see this new giant ITER reactor finished?

ALAIN BECOULET: If you come to France and visit us, you will see all the buildings, services, et cetera, are there. And the machine itself, the tokamak itself, is being assembled. But it’s a very large machine. It’s a very complex device. So this assembly will last another five years, typically, before it is finished to be ready to start.

And then, this machine will start its progressive operation, raising performance power and so on. So the target is expected by 2035.

IRA FLATOW: And you think that, in this new machine, you can actually create a sustained, controlled nuclear fusion for almost an hour.

ALAIN BECOULET: Yes. This is the goal. And it is the way it is designed.

IRA FLATOW: And once that happens, you can then move on to a construction of a practical, functioning, power-producing nuclear fusion reactor?

ALAIN BECOULET: Yes. Which is already under design. I mean, our members, all of them, if not almost all of them, have also reactor design activities in parallel to ITER. So they contribute and they participate to ITER in order to make this demonstration real. And at the same time, they are preparing the first reactors.

IRA FLATOW: You must be just jumping up and down waiting for this to be finished at ITER.

ALAIN BECOULET: Indeed, indeed. And I’m not the only one. [LAUGHS] But no, it’s very exciting. And the other very exciting part is the fact that this is international, and completely international and for a very long time. So it’s multicultural. It’s very, very interesting.

The grail here is really that this kind of electricity source, energy source, has a very large attractiveness, I mean. This is a nuclear reaction based on very light nuclei. So this is something that is not of the kind of the fission reactors creating a lot of nuclear waste, nuclear problems, et cetera. It’s an intrinsically safe process. A nuclear fusion reactor cannot explode, cannot divert. It can only work or stop.

So you have these kind of promises and others that make this research attractive. But it’s a very big challenge. We are trying to capture and to master a small piece of the sun. So it’s something that is extremely difficult.

Mankind today is very attracted and very occupied and busy with trying to move to Mars, OK? And I think that everybody understands how difficult it is to go to Mars, to land on Mars, to live on Mars. Fusion is trying to do the same kind of things, but to go on the sun, in a sense, OK? So we are trying, also, to achieve this kind of very, very challenging goal. But if we manage to do that– and there are still, I mean, there are still a lot of things to do to be able to master this, but if we manage to do that, yes, then we have a potentially very interesting, very inexhaustible, in a sense, source of energy, really, for mankind for quite some time.

IRA FLATOW: I’ll tell you what. We’ll meet back here when you have either finished–


IRA FLATOW: And we’ll be very happy to talk about it then, and we wish you great luck in trying to capture the sun.

ALAIN BECOULET: That’s very kind. Thank you so much.

IRA FLATOW: Alain Bécoulet is head of the engineering domain at ITER in France. He’s also the author of the upcoming book Star Power– ITER and the International Quest for Fusion Energy.

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