Power pistons: General Fusion's reactor is a metal sphere with 220 pneumatic pistons designed to ram its surface simultaneously. The ramming creates an acoustic wave that travels through a lead-lithium liquid and eventually accelerates toward the center into a shock wave. The shock wave compresses a plasma target, called a spheromak, to trigger a fusion burst. The thermal energy is extracted with a heat exchanger and used to create steam for electricity generation. To produce power, the process would be repeated every second.
General Fusion
A startup snags funding to start early work on a low-budget test reactor.
General Fusion, a startup in Vancouver, Canada, says it can build a prototype fusion power plant within the next decade and do it for less than a billion dollars. So far, it has raised $13.5 million from public and private investors to help kick-start its ambitious effort.
Unlike the $14 billion ITER project under way in France, General Fusion's approach doesn't rely on expensive superconducting magnets--called tokamaks--to contain the superheated plasma necessary to achieve and sustain a fusion reaction. Nor does the company require powerful lasers, such as those within the National Ignition Facility at Lawrence Livermore National Laboratory, to confine a plasma target and compress it to extreme temperatures until fusion occurs.
Instead, General Fusion says it can achieve "net gain"--that is, create a fusion reaction that gives off more energy than is needed to trigger it--using relatively low-tech, mechanical brute force and advanced digital control technologies that scientists could only dream of 30 years ago.
It may seem implausible, but some top U.S. fusion experts say General Fusion's approach, which is a variation on what the industry calls magnetized target fusion, is scientifically sound and could actually work. It's a long shot, they say, but well worth a try.
"I'm rooting for them," says Ken Fowler, professor emeritus of nuclear engineering and plasma physics at the University of California, Berkeley, and a leading authority on fusion-reactor designs. He's analyzed the approach and found no technical showstoppers. "Maybe these guys can do it. It's really luck of the draw."
The prototype reactor will be composed of a metal sphere about three meters in diameter containing a liquid mixture of lithium and lead. The liquid is spun to create a vortex inside the sphere that forms a vertical cavity in the middle. At this point, two donut-shaped plasma rings held together by self-generated magnetic fields, called spheromaks, are injected into the cavity from the top and bottom of the sphere and come together to create a target in the center. "Think about it as blowing smoke rings at each other," says Doug Richardson, chief executive of General Fusion.
On the outside of the metal sphere are 220 pneumatically controlled pistons, each programmed to simultaneously ram the surface of the sphere at 100 meters a second. The force of the pistons sends an acoustic wave through the lead-lithium mixture, and that accelerates into a shock wave as it reaches the plasma, which is made of the hydrogen isotopes deuterium and tritium.
If everything works as planned, the plasma will compress instantly and the isotopes will fuse into helium, releasing a burst of energy-packed neutrons that are captured by the lead-lithium liquid. The rapid heat buildup in the liquid will be extracted through a heat exchanger, with half used to create steam that spins a turbine for power generation, and the rest used to recharge the pistons for the next "shot."
The ultimate goal is to inject a new plasma target and fire the pistons every second, creating pulses of fusion reactions as part of a self-sustaining process. This contrasts with ITER, which aims to create a single fusion reaction that can sustain itself. "One of the big risks to the project is nobody has compressed spheromaks to fusion-relevant conditions before," says Richardson. "There's no reason why it won't work, but nobody has ever proven it."
Researchers at Lawrence Livermore National Lab will try to start self-sustaining fusion reactions using the world's largest laser system.
Researchers at a California National Lab will soon attempt to start self-sustaining fusion reactions using the world's largest lasers. If it works, it could be a first step on the road to abundant fusion power.
Now complete, the National Ignition Facility could soon create controlled fusion using lasers.
Another thought on this technique. Being pulsed, the fusion reactor itself should be easier to shut down than a reactor that starts, and then simply contains the reaction.
While I am sure there are reasons why this wouldn't happen, I have visions of containment failing on a continuing reaction and then having a mini-star creating havoc and the end of days.
Just a matter of perception, probably, and not of actual probability. None the less, that perception may well have an impact on investors and VCs.
And this approach seems to be more likely to be cost effective as the government is not involved. As a wag once said:
"An elephant is a mouse built to government specifications"
if fusion containment is lost the reaction stops immediately. it doesn't have the self-sustaining quality of fission reactions, unless it is actually in a star. and the amount of heat contained in the plasma at any one time is not enough to burn you.
Wow, what a potential "steam punk"-esque power source! Can't you just imagine the sound of this thing hammering away once a second, with the steam-powered auxiliary units hissing in the background? BTF, all right, but more the locomotive from the 1800's episode than the silent Mr. Fusion! Yee-haw! ;-)
Seriously, though, this unit's gotta have to have some serious metallurgical engineering built in. Imagine the stresses on the containment shell, being hammered violently every second, while being subjected to repeated radiation and thermal pulses from the thermonuclear reactions, all while holding in a swirling lead-lithium molten metallic brew. All I can say is that I hope they put this thing in a good containment building! :-/
This design has two major advantage over other fusion designs.
The first is that 1.5 meters of liquid lead/lithium will easily absorb all forms of radiation no matter how intense the reactions are. This liquid metal will never wear out or degrade and will not need to be replaced. Other reactor designs have incredibly expensive components that will wear out due to radiation damage. So what if you could build a working tokamak or laser ignition reactor for 20 billion dollars if half the components are destroyed by radiation after a few weeks.
The second advantage is that the lithium will concentrate near the center of the reactor due to the centrifugal force of the vortex and absorb high energy neutrons and thus generate an abundance of tritium, a highly reactive fusion fuel.
Of course this assumes it will work. I am a bit concerned that the vaporized lead will quench the nuclear reaction. And I also have no idea how they can possibly map the turbulence of the molten metal. I am thinking that the various regions of hot and hotter liquid metal will refract the spherical compression wave into some kind of distorted pancake shape before it reaches maximum density.
At high enough power it may still work.
Best of luck fellas.
as others have mentioned, the reaction that would be used gives off neutrons which are not affected by magnetic fields so the metal will become radioactive. I don't know how quickly.
Guest (gacutil)
Take a look at their careers page--they're looking to hire a computational whiz to model the reaction. I think you're right about the distortions caused by the varying densities.
If this problem is remotely like modeling the inside of jet engines, then they'll wind up modeling the interaction of each molecule at the boundaries. Supercomputer, anyone?
Vancouver, eh? Where the antigravity inventor was. And the quantum computer company a few years ago. But is it really out of Vancouver?
"Speaking on behalf of the inventor of this scheme, CEO of the establishment where the research is being done said today:
'We are pleased with the quick progress and ingenuity, being shown in his new occupation', said Warden Ingram, 'of Mr. Madoff...' "
So is this like a hydrogen bomb but in controlled manner? If so, it sounds like it might just work.
Not really. A hydrogen bomb is fusable material around a fissile "spark plug" surrounded by a uranium tamper and set off by a standard fission bomb. The fission bomb compresses the fusion fuel the same way the conventional explosives compress the fission bomb. This is the standard Teller-Ulam design.
The reactor design they are talking about here uses a spherical acoustic compression wave to ignite a small amount of plasma fuel by collapsing the containing space on it, with the intent being a relatively small amount of heat production, which they repeat at intervals to get enough thermal output to drive a steam turbine (and use the steam, in turn, to drive the rams).
It's a moderately interesting design idea, and of course the question is whether they are going to get the funding to build one, and if they do, if it will work as advertised.
Hmmm... I wonder what the mean time between failure for those pneumatic pistons will be?
A more benign design is under construction fusing hydrogen and boron in a plasma field. It will emit an electron beam and has no fission by-products. See the Focus Fusion web site:
http://focusfusion.org/
The most amazing achievement by these Canadians is managing to get 14 million in funding, their chances of fusing two atoms ..... low.
From what I have read and seen, they have spent quite a bit of money, and not a single neutron yet.
I have some experience with this subject, having invented and built a fusion reactor myself, I know how hard it is to get two atoms to fuse.
After spending A$40,000 of my own money, I would have loved to have a few million to continue my work with. After all, our reactor does fuse atoms..
Steven
Bee Research Pty Ltd
http://www.beeresearch.com.au
Aneutronic fusion reactor relies on electrostatic acceleration employing energy more efficiently.
Many "Fusion" Results Actually Depend upon Bessler Principle
Sun's Power Source Misunderstood. General Fusion has a hot fusion approach. I think that there is much confusion about many "hot fusion" approaches, including the sun, as a prime example. The sun is popularly assumed to receive its power from hot fusion. If the sun receives or received its power primarily from hot fusion, then why is it that with more exposure to the very cold 3 degrees Kelvin background temperature of space that the sun's temperature is larger? The observed temperatures are exactly the opposite that one would expect, if the sun actually had been getting its power primarily from hot fusion. Sunspots are not brighter than the 6000 degrees Kelvin photosphere. The sunspots are darker, deeper, and cooler than the photosphere. They have vertical magnetic fields that tend to prevent nuclei from internally rotating about horizontal axes. The far edges of the sun's atmosphere has the least interference between nuclei but there can be temperatures associated with those locations on the solar corona on the order of 1000000 degrees Kelvin (according to some solar corona measurements). The temperatures associated with those non-interfering nuclei would not be due to hot fusion.
Bessler Principle. Nuclear ground states (each internally rotating about horizontal axes) on the sun pick up additional rotational kinetic energy using the Bessler principle. An isolated proton or hydrogen atom at the far edges of the sun's atmosphere with some internal angular speed about a horizontal axis can increase in its internal angular speed by absorption of a two-part graviton. An energetic photon may be produced, when an electron encounters the rapidly rotating proton. See the URL, http://www1.iwvisp.com/LA4Park/GravitySummaryNews.txt , for more information on the Bessler principle, for some more discussion of how the sun obtains its power, for some information on how cold fusion works, for some information on how the GEET reactors work, and for some information on how the Papp engines should be made to work again (using hydrogen nuclei and high reflectivity of internal surfaces within the spark chambers). Notice that the hydrogen nucleus (a proton) (of all nuclei) has the largest ratio of nuclear magnetic moment to moment of inertia so that it would be most easily rotated by a spark within a Papp engine and acquire internal rotational kinetic energy by the Bessler principle. The leakage currents in magnetically confined hot fusion experiments can be attributed to nuclei rotating about horizontal axes (in the presence of horizontal magnetic fields) which produce counter magnetic fields that weaken the magnetic confinement bottles. Many phenomena/studies should properly account for the Bessler principle.
Test Bessler Principle in Space. The Bessler principle could be directly tested out in space by (1) rotating (with very low friction) a cylinder in space about a horizontal axis and (2) observing whether or not it increases its angular speed, until it is at equilibrium with respect to friction. When will such simple experiments be done? I made a suggestion to NASA that they do such experiments. The results of such experiments has much importance with respect to the proper interpretation/analysis of observations coming out of "fusion" experiments.
Select Vortex Axis Carefully. Here is one further note regarding the General Fusion approach. If the vortex is about a horizontal axis, then rotational kinetic energy would be obtained by the Bessler principle. If the vortex is about a vertical axis, then little rotational kinetic energy would be obtained by the Bessler principle. General Fusion must make a careful decision about which axis they want the vortex rotating about, if they want to allow rotational kinetic energy to be contributed from the Bessler principle. The Bessler principle is the actual primary power source for the sun and the actual primary power source for many other things.
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djs
25 Comments
in case of success?
Already in the 80s or 90s there was a news story about a tokamak that reached energy break-even but had to be switched off after a couple of milliseconds to avoid making the machine so radioactive that it would be impossible to approach it afterwards. Fusion energy consists of fast neutrons, alpha particles and gamma radiation, which is "heat" at fusion temperatures. What would happen with all the lead and the steel that would be bombarded with all that radioactivity in an actual power reactor driven by fusion?
Reply
kearns
30 Comments
Re: in case of success?
Actually engineers have had quite a few years to experiment with radiation's effects on materials. My dad sold stainless steel to the nuclear industry a few decades ago for use in reactors. They had to reformulate the steel because conventional alloys would swell and then you couldn't get the stainless steel fuel rods out of the reactor leading to some potentially severe maintenance problems as you can imagine. They corrected the problem and moved on.
Reply
erbium
340 Comments
'fusion energy consists of..'
while neutrons will make the containment facility radioactive after years (if they ever get it going),
if they don't use deuterium as the fuel
but use helium 3 then the lone product is protons which can be contained by the magnetic fields, so not causing container radioactivity.
http://en.wikipedia.org/wiki/Nuclear_fusion
http://en.wikipedia.org/wiki/Helium-3
while deuterium is abundant in our oceans,
helium3 is abundant on moon surface from solar bombardment.
I like this idea. The reactor is likely magnitudes less expensive than the govt funded projects.
Starting us on the way to the coffee-grinder sized 'Mr. Fusion' from BTF or 'micro-fusion generators' from various trekie episodes or movies.
Reply
jbeufer
1 Comment
Re: 'fusion energy consists of..'
Unfortunately, D-3H fusion cross-sections are significantly lower than for D-T at reasonable plasma temperatures.
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erbium
340 Comments
Re: 'fusion energy consists of..'
Yes, I was only pointing out to the original poster that there are multiple fusion reactions possible with different outputs, in the big picture anything up to iron could be fused to produce energy with lessening energy and higher input energy generally. and of course anything above iron could be 'fizzed' to produce energy, with, in general, the reverse of the fusion curve.
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