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Comments: 147 +- Science: Piston-Powered Nuclear Fusion on Friday July 31 2009, @11:09PM
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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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Steam punk angle? (Score:5, Interesting)
Gawd (Score:3, Funny)
Soon everyone will be asking hey.. Does that reactor run Fusex?
I think you get the point
OK, interesting (Score:4, Insightful)
Wouldn't it be funny if it worked?
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So its a hydrogen bomb (Score:3, Insightful)
Re:So its a hydrogen bomb (Score:5, Interesting)
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Re:So its a hydrogen bomb (Score:4, Informative)
The huge yield of Castle Bravo was more due to the unexpected reactions with lithium-7. It wasn't expected to react, but it does capture neutrons, then decays into tritium + a neutron. The tritium quickly fuses with deuterium and releases yet more neutrons. Much of the yield was from the uranium casing, but the reason was the extra high energy neutron flux from the lithium-7. And the secondary in a TU design has the fusion squeezed from both the spark plug detonation (plus a lot of neutrons) and the ablative pressure, on the tamper, from the primary. I'm going to guess that they used a larger amount of the lithium-deuteride because it was only partially enriched. Which meant a lots of unexpected extra energy and neutrons from the lithium-7.
Mr. Burns: [over the hotline] Oh, meltdown. It's one of these annoying buzzwords. We prefer to call it an unrequested fission surplus.
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In other news... (Score:5, Funny)
Colonel Fission is pissed and has vowed to crush General Fusion's puny attempts at creating nuclear energy!
Re: (Score:3, Funny)
Auntie Matter will smooth the whole thing over with tea and crumpets.
Actively stabilized fusion (Score:5, Informative)
There's been some modest interest in actively stabilized fusion for a while, but this is the first mechanical scheme.
The basic problem with fusion reactors is that the plasmas aren't stable. Most work to date involves trying to come up with some geometry that produces an inherently stable plasma. So far, nothing works, although some geometries almost work. But it's not that hard to build a small machine that has an unstable plasma. The original Stellerator, in 1951, did that.
The instabilities occur on the order of milliseconds, not microseconds or nanoseconds. That's slow enough that some kind of active stabilization scheme to nudge the instabilities back in line might work. Something with a large number of sensors and actuators. But I'd been expecting electrostatic deflection plates or magnets, not physical pistons.
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Re:Actively stabilized fusion (Score:4, Interesting)
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.
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I've got an idea (Score:5, Funny)
You could attach four smart mechanical arms to someone's brain stem (with an inhibitor chip of course). Those extra arms could make the millisecond adjustments to keep the instabilities in check. I have to admit this sounds familiar ...
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Re:Actively stabilized fusion (Score:5, Interesting)
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 [rochester.edu], 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.
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Re:Actively stabilized fusion (Score:4, Interesting)
So what's your opinion of Dense Plasma Focus Fusion [focusfusion.org] then?
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Re:Actively stabilized fusion (Score:5, Interesting)
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.
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Re: (Score:3, Insightful)
I don't know what's scarier: that your post was so full of technical jargon, or that I understood all of it.
I think I need to switch fields.
Re:Actively stabilized fusion (Score:4, Informative)
I don't understand why they need the computing power either.
here's work on active stabilization. See "Active-Feedback Control of the Magnetic Boundary for Magnetohydrodynamic Stabilization of a Fusion Plasma" [aip.org]. That's a 2006 paper on a scheme involving 192 active feedback coils to stabilize a plasma. There's other work like that, and hope that one of the designs that's almost stable might be nudged into stability with active control.
Yes but that work was done on the reverse field pinch device called RFX-mod ( http://www.igi.cnr.it/rfxmod2009/ [igi.cnr.it] ). It's a tokamak-like magnetic confinement device so it probably has shot times measured in the multi-second range. Plenty of time for active stabilization but way different from this new MTF approach.
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Re:Actively stabilized fusion (Score:4, Interesting)
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."
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Pulse fusion, it looks like... (Score:5, Informative)
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Re:Pulse fusion, it looks like... (Score:5, Interesting)
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.
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Re:Pulse fusion, it looks like... (Score:4, Informative)
So it's a perpetual motion machine?
What on earth gave you that impression? Converting lithium to tritium leaves less lithium behind, and the energy would be coming from rearranging nucleons. No perpetual motion there at all.
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Re: (Score:3, Interesting)
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?
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Nuclear Power [feeddistiller.com] Feed @ Feed Distiller [feeddistiller.com]
Code Name: Penuts (Score:4, Funny)
p11B (Score:4, Informative)
Perhaps if the D-T reactor does really well they can redesign it to handle a fuel composed of hydrogen ions (protons, in other words) and Boron-11 ions. The products of this reaction are helium-4 ions, which are not radioactive and do not induce radioactivity in their containment vessel if they are captured electrically. Electrical capture also avoids the losses associated with converting heat to electricity.
I really hope General Fusion gets this to work, but if I had any money, my money would be on EMC2 Corp, which is working on inertial electrostatic fusion. This [blogspot.com] or this [emc2fusion.org] should get you started on a search for more information.
Re:p11B - Better link (Score:3, Interesting)
Perhaps this [blogspot.com] is a better link for Polywell Fusion.
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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.
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Oops, the half life of 205Pb is long enough to make it a problem. There won't be a lot of it, though, as 204Pb is only 1.4% of natural lead.
Interesting... (Score:4, Informative)
Well.. (Score:3, Funny)
Fantastic Fiction (Score:3, Funny)
Re:Fantastic Fiction (Score:5, Insightful)
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Re: (Score:3, Informative)
Was real? My office is just down the street from them. Sure they aren't doing that cool Project Orion stuff anymore but they're still here.
Nice try (Score:3, Funny)
But that's never going to fit on a DeLorean. Why don't these guys ever plan ahead?
Who knew? (Score:3, Funny)
that the Batmobile had a 220-cylinder engine?
New Idea? (Score:4, Funny)
Maybe we should just move all companies and their fusion experiments to one, single 'fusion science park', with each building next to each other in a ring. We then use large bulldozers to smash all the buildings towards the centre at the same time and see what happens?
It's an idea? No?
There is reason to be concerned. (Score:5, Insightful)
Startups, by their very nature, do not succeed on a bet that the technology will be invented. Venture capitalists do not support fairytale wishes.
Startups use existing, proven technology and package it in new ways to serve a need of the consumer. Startups are about commercializing a technology, not inventing it.
What startup does breakthrough research? None.
Research is the luxury of universities (with infinite time horizons) and monopolists like Microsoft .
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Re:There is reason to be concerned. (Score:5, Insightful)
It's exactly that kind of short-sighted thinking that has driven nearly every commercial research and development laboratory out of the United States.
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Re:There is reason to be concerned. (Score:4, Insightful)
In his defense, a company can't exactly sustain itself without some type of income.
Research is something an established company can afford to do.
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Re:There is reason to be concerned. (Score:5, Insightful)
Research is something an established company can afford to do.
Mod me flamebait, but from the amount of money the US government spends on securing oil, there really shouldn't be any problems with fusion research funding.
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Re:There is reason to be concerned. (Score:5, Interesting)
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.
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Re:There is reason to be concerned. (Score:4, Informative)
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Re:There is reason to be concerned. (Score:4, Insightful)
Startups, by their very nature, do not succeed on a bet that the technology will be invented. Venture capitalists do not support fairytale wishes.
So very, very ill-informed. Betting on needed technology being invented is a risk and the very thing venture capitalists do is to take great risks expecting to reap in big profits. Profits that cover more than all their other risky investments that fail since they expect most to fail. That is the definition of venture capitalist.
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Re:If the government did research that proved (Score:4, Informative)
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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 h
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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:Few bad points (Score:4, Insightful)
Relocating to the Vancouver area is a bad point? What world are you living in? On Earth Vancouver is frequently ranked among the planets most livable cities.
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