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Power Science

Piston-Powered Nuclear Fusion 147

katarn writes "General Fusion is a startup proposing they can create commercially viable fusion using acoustic shock waves, triggered by 220 precisely controlled pneumatic pistons. Their approach is based on a US Naval research concept called 'Linus' and old research done by General Atomics. They feel we now have the high-speed, digital processing capable of pulling off this feat, where decades ago the technology was not available. I think we can hold off on the 'vaporware' claims for a bit; everyone is aware of the horrible track record for turning fusion concepts into reality, but they don't claim to be the first with the idea or that there are not substantial challenges in the way. If nothing else, it is a fascinating concept." Los Alamos National Laboratory has further details on this type of fusion, and longtime LANL researcher Ronald Kirkpatrick did an external assessment (PDF) of General Fusion's plans. Popular Science had a lengthy story about the company a while back. The reason they're back in the headlines now is that they've secured enough funding to begin work on a prototype reactor.
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Piston-Powered Nuclear Fusion

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  • Steam punk angle? (Score:5, Interesting)

    by houstonbofh ( 602064 ) on Saturday August 01, 2009 @12:16AM (#28905875)
    I mean, come on, this is just begging for some steam punk artwork!
  • by MichaelSmith ( 789609 ) on Saturday August 01, 2009 @12:35AM (#28905987) Homepage Journal
    I wonder if this could be turned into a rocket engine? It has an EE Smith feel about it.
  • by pitterpatter ( 1397479 ) on Saturday August 01, 2009 @01:10AM (#28906183) Journal

    Perhaps this [] is a better link for Polywell Fusion.

  • by Rei ( 128717 ) on Saturday August 01, 2009 @01:26AM (#28906259) Homepage

    One neat thing that they didn't mention: having lithium exposed to a high radiation flux will breed more tritium. It makes its own fuel.

  • by deglr6328 ( 150198 ) on Saturday August 01, 2009 @01:44AM (#28906341)

    Uhhhh, what are you talking about? The plasma parameters are not by any means, in so far as I can see, actively controlled in any way in this scheme. Their plan is to launch two colliding toroidal vortex rings of hot plasma into the vorticular void of a large sphere or rapidly spinning molten LiPb metal. Then, using pistons, they launch an imploding spherically symmetric shockwave into the metal to converge upon the merged spheromaks at the center of the setup. The TOTAL confinement time looks like it'll be measured in microseconds at most on this thing, no way is there time for active control of the plasma during a shot like that.

    As fusion schemes go, I am obligated to express my opinion that this one is way fucking wacky, however, it is significantly less wacky than a lot of other ideas out there (polywell, I'm looking at you) and it does not appear to have any immediate show stoppers associated with it which would allow me to dismiss it out of hand. I am not a physicist, but I did just get home from my job working on one of the nation's largest conventional (laser driven) inertial confinement fusion reactors and I have a very deep enthusiast's interest on these matters. On the laser fusion device that I work on, we have recently begun shooting MTF targets (we call it MIF or magneto-inertial fusion though) on our system as well [], and the results are quite interesting. We use a centimeter scale, single loop Helmholtz coil setup with a conventionally laser-driven fusion microcapsule sitting at the center of the coils. The laser fires, compressing the D-T fuel to tremendous pressure and temperature (higher than in the sun's core) and just before the exact moment of maximum compression and fusion burn (bang time) the Helmholtz coils are fired with power from a couple hundred Joule capacitor bank, thereby producing a huge magnetic field in the compressed target capsule and hopefully increasing the plasma confinement time from a mere few picoseconds to several times longer (the Larmor radius of charged particles in a magnetic field of the intensity we produce is on the order of the size of the compressed capsule, it effectively suppresses electron thermal conductivity and confines the hot plasma within itself). Proton deflectrometry has been successfully used to validate the expected ~.2 megagauss magnetic fields in our setups. The work ahead of the guys with this piston driven shockwave idea is enormous, but the field of plasma and fusion physics is still rich with exciting discovery. I wish these gentlemen the very best of luck.

  • by QuantumG ( 50515 ) * <> on Saturday August 01, 2009 @02:32AM (#28906541) Homepage Journal

    So what's your opinion of Dense Plasma Focus Fusion [] then?

  • Re:So, (Score:3, Interesting)

    by Entropius ( 188861 ) on Saturday August 01, 2009 @02:45AM (#28906603)

    Probably. If it's scientific and computer-y, it's probably powered by penguins.

    I just got back from a computational physics conference, and I doubt anybody there would have the slightest idea how to make a supercomputer run on Windows.

  • Re:p11B (Score:3, Interesting)

    by WalksOnDirt ( 704461 ) on Saturday August 01, 2009 @02:50AM (#28906625)

    My guess is that 204Pb will absorb a neutron and transmute to 205Pb, which decays to a stable isotope of thallium, and 208Pb will transmute to 209Pb, which decays to nearly stable bismuth. The other lead isotopes look like they should just become heavier stable lead isotopes. I don't see any obvious waste problems here.

  • by jamesh ( 87723 ) on Saturday August 01, 2009 @03:08AM (#28906735)

    What happens to the lead when it absorbs the radiation? If it's fusion then there aren't a lot of neutrons let off but does it still remain stable (ie remain lead) over a long period?

  • by deglr6328 ( 150198 ) on Saturday August 01, 2009 @03:15AM (#28906779)

    I won't sugarcoat my thoughts on that one, I'd say it's nothing more than a fraud. The lowest of the low, vastly kookier than even Bussard's Polywell. I have followed discussions about Eric Lerner and focus fusion VERY closely on the wikipedia pages and I have little to no respect for that man's ideas about fusion or his tactics of argument. He does not have a PhD and he is not a physicist. His ideas about the "electric universe" are idiotic pseudoscience. I will refer you specifically to the plasma physicist Art Carlson's highly thoughtful and reasonable objections to unconventional fusion schemes in general on this issue, and his objections to focus fusion in particular (all on the wiki pages). His credentials and intellectual honesty in these debates seem, to me anyway, to be impeccable.

    Robert Bussard can be forgiven for his sin of the polywell. He was a really good scientist who achieved some truly admirable things in his career, but at the end I think he realized that he was getting old and would never live to see his dream of fusion power come true, and he started making wacky claims when things became desperate (like extrapolating his supposed observation of three -count em- THREE fusion neutrons from one of his setups to commercial scale power cost estimates, that's just pain nutty). It's unfortunate but entirely forgivable. Art Carlson's criticism of the polywell device as a non-starter due to its being classified as a reactor whose plasma is in thermodynamic disequilibrium (Todd Rider's MIT thesis on this showed that the bremsstrahlung losses are insurmountable) are highly convincing, and the waffling and flouncing about that the polywell supporters do in the face of these criticisms seem highly dubious.

  • by jpmorgan ( 517966 ) on Saturday August 01, 2009 @03:45AM (#28906917) Homepage
    Only in the vaguest sense. The secondary stage in a thermonuclear bomb is triggered by a fission primary, however the secondary stage in a thermonuclear bomb is not a purely fusion weapon. It's a multilayer sandwich. The secondary starts off with another fission reaction (the plutonium spark-plug), which helps trigger the fusion reaction (lithium deuteride), which in turn boosts the ongoing fission reaction in the spark plug, which in turn boosts the ongoing fusion reaction. Finally it produces a neutron flux which detonates and consumes the secondary casing (depleted uranium, U-238). Most of the energy in a thermonuclear bomb comes from the fission of the depleted uranium protective casing. Thermonuclear bombs do fission 'better' than purely fission bombs. For the record, this was discovered accidentally when Castle Bravo was a much bigger bang than the designers expected.
  • by mako1138 ( 837520 ) on Saturday August 01, 2009 @04:57AM (#28907203)

    But it's not that hard to build a small machine that has an unstable plasma.
    The original Stellerator, in 1951, did that.

    Uh, the advantage of a Stellarator is that it's a stable configuration... relatively speaking.

    And indeed it is not difficult to build a machine with an unstable plasma. The history of magnetic confinement fusion research is "oh I've got this great idea for a stable plasma configuration" followed by "we built it and found out that it's not stable enough."

  • by physburn ( 1095481 ) on Saturday August 01, 2009 @08:09AM (#28907845) Homepage Journal
    Yeah the lead will absorb radiation, but when it absorbs those fast neutrons from the fusion reaction, it will split like uranium does in fission. Except some very nasty radioactive daughter products. With the lead, this is not be clean energy, it will rather dirty indeed.


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  • by WindBourne ( 631190 ) on Saturday August 01, 2009 @08:10AM (#28907857) Journal
    The US govt does an incredible amount of RD that they never follow up on i.e. it is more Rd, rather than RD. The reason is money. Take the example of TransHab. Thankfully, Bigelow has been pursuing it. If we are VERY lucky, the Augustine commission will recommend that we buy one or two and attack to the ISS to help him alone.

    And this particular example, the Navy does a LOT of nuke funding. Have to. If we can create a reactor that is much smaller in size, it will change a lot of things for US. DARPA also has its fair share of black funding.
  • Re:VSE (Score:2, Interesting)

    by Luxifer ( 725957 ) <geek4hire@gma[ ]com ['il.' in gap]> on Saturday August 01, 2009 @09:48AM (#28908317)

    Wow, you're too bitter to be a Canadian by birth, and you didn't apologize once. where you from originally?

  • by quanminoan ( 812306 ) on Saturday August 01, 2009 @10:05AM (#28908431)
    Polywell more wacky than this? There are a number of things I can't see them getting right with this piston concept any time soon. Personally, I don't think they can make a uniform shockwave using pistons, but we'll see I guess. The plasma vortex rings sounds interesting. I guess my primary question would be using the lead lithium blanket next to the plasma. Invariably, you'll have some vapor in the plasma region, and these higher Z atoms should wreck havoc with Bremsstrahlung radiation. The polywell already produces neutrons from fusion, avoids Bremsstrahlung more than the original "fusor" concepts, and should be scalable. Granted, I actually feel that the more conventional schemes have a greater chance of success currently. ITER should break even...
  • by arkenian ( 1560563 ) on Saturday August 01, 2009 @10:21AM (#28908515)

    Why flamebait? You are correct. I would also like to add the US military budget...

    The US has the means to fund this research. It has chosen not to do so.

    Ummmm. Just want to note that historically speaking the Department of Energy has funded nearly as much in research dollars as the Department of Defense, and that the amount of money spent on (failed) attempts at fusion is not insignificant by any means. You don't see all that much money going to fusion research these days because not many people have come up with NEW ideas that have any sort of solid backing in theoretical physics. In fact, most physicists would argue that its STILL way, way, too easy to get research dollars for purely ridiculous ideas of generating fusion. I will also add that there are still relatively substantial funds going into hot fusion and attempts to improve the energy balance from there. Finally, this whole point is irrelevant to the parent -- large government grants for basic research usually don't go to startups simply because there's no track record of research success etc. Instead they typically go to universities and other established research centers -- and I assure you that the average university has plenty of grants awarded for stuff pretty far out there. On the other hand the Small Business Initative Research grants from DoD etc. are actually a fairly impressive program. While there is definitely no such thing as spending too much money on research, so far as I am aware the US is still on the leader board in terms of research spending.

  • by PinkyGigglebrain ( 730753 ) on Saturday August 01, 2009 @01:28PM (#28910099)
    I think it could. (IANARS, but I play one on /.)

    Not a ground to orbit engine, the assembly would be too heavy for the max thrust of current non-chemical fueled engines. But once in orbit the energy generated could run a VASIMR, conventional ion or water/steam based thruster quite well. With something like that Mars would be less than 6 month round trip, the outer planets and more importantly asteroids would be within practical reach. This kind of engine could be used to bring an asteroid into Earth orbit for mining or divert a rock on an impact trajectory.

    The more I think about it the more I think this idea is just crazy enough to work.
  • by moosesocks ( 264553 ) on Saturday August 01, 2009 @05:57PM (#28912113) Homepage

    I'm a bit curious as to why we haven't heard more about a fusion reactor based around Sandia's Z-Pinch.

    AFAIK, the Z Machine has experimental results showing that efficient fusion could be achieved using a similar technique. Why aren't we pouring all of our resources in this direction, given that we've got evidence showing that it will work? Tokamak designs seem to have a tendency to be outrageously large, expensive, and unproven.

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