Small Fusion Reactors Finally Plausible?

Aviation Week was given an exclusive story on Lockheed Martin, the largest defense contractor in America, having developed what they say is the first realistic design for a small fusion reactor capable of powering everything from an airplane to a city. If true, this is a monumental development.

Although the company released limited information on the CFR in 2013, Lockheed is now providing new details of its invention. Aviation Week was given exclusive access to view the Skunk Works experiment, dubbed “T4,” first hand. Led by Thomas McGuire, an aeronautical engineer in the Skunk Work’s aptly named Revolutionary Technology Programs unit, the current experiments are focused on a containment vessel roughly the size of a business-jet engine. Connected to sensors, injectors, a turbopump to generate an internal vacuum and a huge array of batteries, the stainless steel container seems an unlikely first step toward solving a conundrum that has defeated generations of nuclear physicists—namely finding an effective way to control the fusion reaction.

“I studied this in graduate school where, under a NASA study, I was charged with how we could get to Mars quickly,” says McGuire, who earned his Ph.D. at the Massachusetts Institute of Technology. Scanning the literature for fusion-based space propulsion concepts proved disappointing. “That started me on the road and [in the early 2000s], I started looking at all the ideas that had been published. I basically took those ideas and melded them into something new by taking the problems in one and trying to replace them with the benefits of others. So we have evolved it here at Lockheed into something totally new, and that’s what we are testing,” he adds…

The CFR will avoid these issues by tackling plasma confinement in a radically different way. Instead of constraining the plasma within tubular rings, a series of superconducting coils will generate a new magnetic-field geometry in which the plasma is held within the broader confines of the entire reaction chamber. Superconducting magnets within the coils will generate a magnetic field around the outer border of the chamber. “So for us, instead of a bike tire expanding into air, we have something more like a tube that expands into an ever-stronger wall,” McGuire says. The system is therefore regulated by a self-tuning feedback mechanism, whereby the farther out the plasma goes, the stronger the magnetic field pushes back to contain it. The CFR is expected to have a beta limit ratio of one. “We should be able to go to 100% or beyond,” he adds.

This crucial difference means that for the same size, the CFR generates more power than a tokamak by a factor of 10. This in turn means, for the same power output, the CFR can be 10 times smaller. The change in scale is a game-changer in terms of producibility and cost, explains McGuire. “It’s one of the reasons we think it is feasible for development and future economics,” he says. “Ten times smaller is the key. But on the physics side, it still has to work, and one of the reasons we think our physics will work is that we’ve been able to make an inherently stable configuration.” One of the main reasons for this stability is the positioning of the superconductor coils and shape of the magnetic field lines. “In our case, it is always in balance. So if you have less pressure, the plasma will be smaller and will always sit in this magnetic well,” he notes.

Overall, McGuire says the Lockheed design “takes the good parts of a lot of designs.” It includes the high-beta configuration, the use of magnetic field lines arranged into linear ring “cusps” to confine the plasma and “the engineering simplicity of an axisymmetric mirror,” he says. The “axisymmetric mirror” is created by positioning zones of high magnetic field near each end of the vessel so that they reflect a significant fraction of plasma particles escaping along the axis of the CFR. “We also have a recirculation that is very similar to a Polywell concept,” he adds, referring to another promising avenue of fusion power research. A Polywell fusion reactor uses electromagnets to generate a magnetic field that traps electrons, creating a negative voltage, which then attracts positive ions. The resulting acceleration of the ions toward the negative center results in a collision and fusion.

The team acknowledges that the project is in its earliest stages, and many key challenges remain before a viable prototype can be built. However, McGuire expects swift progress. The Skunk Works mind-set and “the pace that people work at here is ridiculously fast,” he says. “We would like to get to a prototype in five generations. If we can meet our plan of doing a design-build-test generation every year, that will put us at about five years, and we’ve already shown we can do that in the lab.” The prototype would demonstrate ignition conditions and the ability to run for upward of 10 sec. in a steady state after the injectors, which will be used to ignite the plasma, are turned off. “So it wouldn’t be at full power, like a working concept reactor, but basically just showing that all the physics works,” McGuire says.

Now I’m certainly no physics expert (and I’d love to hear from those who are), but I’m giving this a lot more credibility than the usual cranks working in their garages who claim to have produced cold fusion and the like. This is a huge corporation that has spent a massive amount of money on this research and they know how bad it would be for them to announce such a breakthrough if they weren’t pretty certain it would work.

But there are still potential problems. The physics may turn out to be wrong, for instance. Or the actual material development of the units might end up being either impossible or far too expensive (though the latter seems unlikely). Still, if this technology becomes a reality it will mean a revolution in how we generate energy and would dramatically reduce our use of fossil fuels, which can only be a good thing.

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  • Sunday Afternoon

    If I am reading the description correctly, tokamak designs for fusion require some sort of active control of the magnetic fields that contain the plasma and keep it from the chamber walls. As the fusion begins, you can imagine that the energy generation changes the magnetic field strength that is required for containment. I imagine that these changes are large and can happen quickly, making a very difficult control problem.

    The fundamental change here appears to be that the containment is claimed to be inherently stable. The fields respond to the pressures of the reaction without the need for outside control. If this is true, I think we could indeed have a breakthrough.

  • moarscienceplz

    I’m highly skeptical. 1) This article seems to totally gloss over the problem of ignition. Maybe that’s just the reporter’s fault, but achieving fusion temperatures in such a small package is a huge problem in and of itself, so if the Skunk Works have a good handle on it, I would expect them to crow more about it. 2) I’m not aware of any instance where the Skunk Works has demonstrated skill in basic research. All the SW projects I know of were just improvements on existing technologies.

  • tbrandt

    These high-temperature plasmas are unstable to an enormous variety of waves, making plasma confinement very hard. Every time you make them stable against one mode, another one pops up (with diffusion always there at the end). I absolutely do not believe that they have achieved indefinite confinement–check out the wikipedia page on plasma stability for some sobering reading. In this case, you have a head engineer telling his bosses what they want to hear and with little outside review, and giving the story to a popular and friendly outlet (Aviation Week? Really?). Color me skeptical.

  • HappyHead

    My favorite take on this comes from Nuclear Physicist, Dr. Darren Bluel, at:

  • my2cents

    Now my field of study is not physics it’s biology but I was under the impression that for fusion to work you needed large quantities of the isotope Helium-8. I was also under the impression this isotope was very rare except on the moon. Did lockheed figure out a different breakthrough or is this still built on model of using Helium-8? I can’t find any article mentioning if they are going to use a different approach or not.

  • marcus

    I am not skeptical, I am optimistic (because I know fuck-all about any of this).

    I await my fusion-powered bicycle. (That’s what he said, right?)

  • Modusoperandi


  • D. C. Sessions

    I was under the impression that for fusion to work you needed large quantities of the isotope Helium-8

    Helium-8 has a half-life you don’t even want to think about. Helium-4 is the most stable, and 3 is useful as an intermediary. You might want to check your sources on that bit about 8.

  • danielnajib

    I’m highly skeptical, since it seems to require large amounts of Tritium – precluding any widescale development.

  • Nentuaby

    I’m not really that skeptical, but I’m also not reading them to be claiming near as much as some people are interpreting it. Note they’re not actually saying anywhere here that they think they’ll *break even* any time soon. They’re just claiming to expect they’ll reach the current state of the fusion art in a much smaller package.

  • Kevin Kehres

    This looks like a very nice hypothesis, and I’m sure their science is fine.

    But I’ll be way more impressed when they get a working model going.

    I wouldn’t be surprised to be reading about this thing being “5 years away” in 5 years, then 10, then 15…

  • Marcus Ranum

    I’m just happy to see the boffins making something useful, that isn’t designed to shatter bone and mulch meat. If we have to waste money on our defense-industrial complex, this is the way it should be wasted.

    Of course, they’re probably working on it as a power supply for killer drones, or something awful like that. Fuckers.

  • Modusoperandi

    Nentuaby “smaller package”

    That was my stripper name. True story. Sadly.

  • Sastra

    I’m skeptical because the project is admittedly “in its earliest stages” and already they’ve contacted the popular press. Sounds like they’re looking for money.

    Even if this turns out to work, we’re right to be skeptical. This is what so many people don’t seem to understand. They think skeptics would “hate” it if it turns out they should never have doubted in the first place — because it worked! I blame this partly on human nature, and partly on a culture which has turned ‘faith’ into a sort of litmus test for good will and prescience.

  • colnago80

    This is rather far outside my field of expertise but there seem to be at least two problems. The first is the energy budget, namely will the device put out more energy then is consumed by the containment magnetic fields. The second is their claim that the magnetic containment fields generate a positive feedback effect as the plasma is heated. If either or both of these claims are in error, the device won’t work. A quick search failed to find any physicists who have expertise in this area commenting on it. Attached is a commentary by Dr. Steven Novella, a well known skeptic who has had an interest in this field for a long time. However, Novella is a neurologist and his opinions and conclusions should be judged accordingly.

  • D. C. Sessions

    @9: tritium is easy enough to come by — it’s a byproduct of just about every nuclear power process anyone has thought up. You don’t want all that much around, but if you’re using a modest amount to prime a fusion reactor it’s not too bad.

    The Lockheed design uses hydrogen and deuterium compounds to capture neutrons from the fusion and as a coolant/working fluid for the heat engine. hydrogen+N => deuterium, deuterium+N => tritium. Just keep adding hydrogen and enough deuterium to make up for the losses.

  • Pierce R. Butler

    … the Skunk Works experiment, dubbed “T4,” …

    Oh gawd. T4? Really?!?!?!?!?

  • heromachine

    Slate has a good skeptical take on this article.

    Long story short, they haven’t actually built anything, the fundamental idea of the responsive magnetic bottle hasn’t been tested, and they’ve already slipped their date almost since they started.

  • Pierce R. Butler

    Correction to my mislinked # 17:

    Oh gawd. T4? Really?!?!?!?!?

  • colnago80

    Re heromachine @ #18

    Seife is a journalist who really has no more expertise then Steven Novella who I cited @ #15 who is also skeptical. I would prefer hearing from a physicist(s) who specializes in plasma physics. I can recall predictions made in 1970 that controlled fusion was 30 years away (44 years have passed and we seem to be still far away from realization). It may be that the problems are unsolvable.

    It should also be pointed out that Lockeed is the prime contractor for the F35, which may join the air force about the time that controlled fusion is achieved.

  • congenital cynic

    That does it. I’m going to buy an old DeLorean. Mr. Fusion is just around the corner, and then it’s time travel, and then I’m going back to when I met my wife… because, well, you figure it out.

    Seriously though, I don’t believe it. I’d be happy to be proved wrong, but I don’t think it’s credible. I used to work in the nuclear industry (as a chemist/engineer/health physicist), and while not a researcher in plasma physics, I doubt that any kind of small scale fusion is ever going to be possible. The temperatures, forces, and energies are just so extreme. I have doubts that it will work at any scale in my lifetime (I’ve likely got 30 to 35 years to go). The prospect of a terrestrial scale reactor is, in my opinion, questionable. Glad that people are trying, but I’m not holding out hope that my future wheelchair will be fusion powered.

  • joseph

    I am not that familiar with technology reporting, but I am familiar with science reporting. Reporters, even science reporters, often for a variety of reasons get the story wrong and the resulting articles can be misleading.

  • AMM

    I used to work in nuclear fusion research. The field started in the ’50’s and they’ve been announcing that fusion reactors were just around the corner ever since. In practice, getting more or less continuous fusion reactions in anything like earth-like conditions is fiendishly difficult. Each factor-of-two improvement in temperature, size, etc., has presented a menagerie of qualitatively new and unanticipated problems which require developing new physics and engineering disciplines to deal with.

    And, so far, they’ve simply been trying to get fusion reactions to happen at all. “Break even” definitions ignore many of the energy and other costs. Converting those reactions into useful energy is an unsolved — actually unadressed — problem. And once those issues are solved, you have all the usual problems of turning this invention into something practical. E.g., degradation of structures due to neutron influx. Dealing with radioactivated components when they are replaced. Safety. Failure modes.

    As for use in airplanes (or bicycles) — hah! So far, most of the improvements have been gained by making the devices bigger, not smaller.

    tl,dr: Color me skeptical.

  • Gregory in Seattle

    If it sounds too good to be true….

    I find it interesting that this information is coming from a military contractor that has seen its government teat shriveling up. What better way to increase the flow of gravy than by promising a holy grail that provides independence from Russia and Muslim states?

    Until proven wrong, I will call this nothing more than vaporware marketing.

  • pacal

    AMM at no. 23 says:

    The field started in the ’50’s and they’ve been announcing that fusion reactors were just around the corner ever since.,

    That has it exactly right. I remember reading articles in magazines from the 1950’s that described how Fusion was just around the corner and how it would completely change our lives. Well Popular Mechanics et al in the 1950’s got it wrong but the record was repeated in the3 60’s, 70’s etc.

    The problems with fusion reactions and controlling them are such that c. 60 years of research and billions upon billions spent we can only produce fusion reactions for well under a minute. It is possible that fusion may not be feasible at a ‘reasonable” cost or difficulty level at all.

    As it is I suspect usable fusion may only become possible, if at all, in the second half of the 21st century at the earliest.

  • AMM

    we can … produce fusion reactions for well under a minute.

    That’s a huge improvement over where they were when I last looked.

  • Who Cares

    The only thing really interesting in that is the claim of being able to get the β limit to 1. This is the point where the plasma collapses due to instability.

    That would mean the energy in for the magnets can be 1/10 to 1/20 of what ITER is projected to use. This doesn’t make it 10 to 20 times more efficient though since both devices use radio waves to excite the fuel. It would reduce the energy in to 1/4 or 1/5 not the 1/10 that is claimed in the article.

    The claim of cusp confinement has been theorized for polywell type reactors once β gets close to the limit of 1. Not total confinement but a warping of the magnetic fields reducing the amount of plasma that can escape by a factor 100. Which the article says they want to deal with by putting up magnetic mirrors outside the cusps.

    In theory it can work. But then again in theory a polywell type reactor should work too. Reality isn’t that co-operative and polywell designs have been discarded in favor of tokamak reactors, well reactor since most of the work is now focussed on ITER with smaller reactors just testing out bits and pieces for it, or stellarator type reactors or tokamak/stellarator hybrids.

  • congenital cynic

    Well, I can still pick up a really low mileage DeLorean for under $80,000, so what the hell. Maybe I’ll put a whippletree on it and hook up a team of horses. Easier to feed than a fusion reactor.

    We need to go back to Thorium fission reactors. We’d have had them in the first place if the US hadn’t wanted the by products of the Uranium reactors to produce bombs.

  • tacitus

    Lots of good skeptical quotes here:

    I’m guessing that the claimed size of the device (10 times smaller than other fusion reactors) will make it reasonably easy to validate / invalidate in that it won’t cost the earth to get a prototype up and running.

    Would be fantastic even if some of the claims were true, so I guess we shall have to wait and see.

  • waldteufel

    They haven’t even built a prototype or working model, and yet are crowing about a great discovery. I call corporate kookology.

  • voss

    @4 Yeah, Nukees seems to be an accurate assessment.

  • mordred

    Another sceptic here (and another non-expert ;-). The professor who taught nuclear physics at my university said about the whole magnetic confinement fusion something along the line that it works in theory but is made impossible by technical difficulties.

    I don’t know if he was to pessimistic here, but everything I’ve read on the subject makes me really doubt that you can make any predictions on a new type if fusion reactor before building a prototype and encountering all the real world problems!

  • lpetrich

    There’s also the question of how well it can compete with existing technologies for electricity generation. Not only mature ones like hydroelectricity, fossil fuels and nuclear fission, but also up-and-coming ones like wind and solar. Initial versions of most technologies tend to be relatively expensive.

  • paulparnell


    Helium-8?!? That has a half life of about a fifth of a second. It has only been created in tiny (A hand full of atoms) amounts to study the weak force. You may have heard of Helium-3, deuterium and tritium in fusion. But I suspect no helium-8.

  • birgerjohansson

    Extraordinary claims require extraordinary evidence. The compay wants investors to back their design effort. I will not be one of them.

  • lorn

    Color me dubious.

    Lockheed Martin is mainly a defense contractor and defense contractors are notorious for promising the moon to get buy in and a commitment and then moving he goalposts back while demanding more, and more, and more money. In the end they produce something that looks like a middle school project rushed overnight by kids that didn’t read the directions. When their failure to deliver is pointed out in the light of massive cost overruns they accuse all the other contractors on the project of a lack of performance and the extra costs on an ever changing specification, even though they had the biggest hand in writing those changing specifications and were offering ever better results to keep the buyers interest.

    Given the normal course for such programs a few hundred Billion dollars investment in a compact fusion reactor will end with: the grand kids of the top guys at Lockheed will all have yachts, private jets, and beachfront houses and the US government will end up with the world’s most expensive and technically advanced espresso machine. On the up side, it makes one hell of a cup of coffee, as long as you remember to plug it in.

  • comfychair

    I’m confused. Don’t we already have a giant, stable fusion reactor producing more energy that we could ever possibly use, right up there in the sky?

  • Holms

    Yes, but the fraction of that production that we are able to harness is not large enough to be relied upon.

  • colnago80

    Re Holms @! #38

    Actually, given the increases in the efficiency of solar cells over the past 2 decades, this isn’t the real problem. The problem is, what do we do when the sun isn’t shining (at night) or it’s cloudy. Several approaches have been proposed, all of which involve the production of a surplus of energy when the sun is shining and storing the surplus for use when it isn’t. AFAIK, there have been a number of proposals, none of which appear economically viable as we sit here today. However, at least the proposals are technically viable, which is more then we can say about controlled fusion at present.

  • caseloweraz

    Wikipedia lists 57 solar thermal power plants with a total capacity of 3650 MW. Here are the top ten:

    Ivanpah California 392 MW Completed 2/13/2014

    SEGS California 354 MW (9 units)

    Solana Gila Bend, AZ 280 MW Oct 2013 (6-hour thermal storage)

    Genesis California 250 MW 4/24/2014

    Solaben Logrosán, Spain 200 MW 3 of 6 units completed September 2013

    Solnova Sanlúcar la Mayor, Spain 150 MW 3 of 4 units completed August 2010

    Andasol Guadix, Spain 150 MW 2011 (3 units, 7.5 hour thermal storage)

    Extresol Torre de Miquel sesmero, Spain 150 MW August 2012 (3 units, 7.5 hour thermal storage)

    Palma del Rio Palma del Rio, Spain 100 MW 2 units completed July 2011

    Manchasol Alcázar de San Luis 100 MW April 2011 (2 units, 7.5 hour thermal storage)

  • colnago80

    Re caseloweraz @ #40

    Well, I stand corrected. However, these plants appear not to be utilizing solar cells that directly convert sunlight to electricity, which is what I had in mind. Rather, they use convex mirrors to focus sunlight to heat water or some other fluid which is then used to drive turbines to generate electricity.

  • caseloweraz


    You’re correct, of course; these plants use the concentrated heat of sunlight. It would make little sense to convert sunlight into electricity using photovoltaics, then to use some of that electricity to heat molten salts for storage purposes.

    But given a widely dispersed network of PV facilities, along with sufficiently good and inexpensive batteries and a so-called “smart grid”…

  • eric

    I’m giving this a lot more credibility than the usual cranks working in their garages who claim to have produced cold fusion and the like.

    You should. I think a fair amount of good science and engineering know-how could come out of the Lockheed project. Will it achieve its goal? Highly unlikely. But its not crank science, and I’d say the chances are highly likely that the scientific community learns something beneficial from the effort. So I’m giving it a thumbs up. My prediction is that Lockheed will not-find fusion in a very interesting and valuable way.