Slashdot Mirror
New 'Stellarator' Design for Fusion Reactors
eldavojohn writes "The holy grail of fusion reactors has always seemed 'just a few years off' for many decades. But a recent design enhancement termed a 'Stellarator' may change all that. The point at which a fusion reactor crashes is when particles begin escaping due to disruptions in the plasma. A NYU team has discovered that coiling specific wires to form a magnetic field may contain the plasma. This may be a a viable way to create a plasma body with axial symmetry, and a far better chance of remaining stable. Like other forms of containment this does require energy itself, but could bring us closer to a stable fusion reactor. It may not be cold fusion or 'table top' fusion but it certainly is a step forward. The paper is up for peer review in the Proceedings of the National Academy of Sciences."
...they want credit.
Picture Chinese handcuffs
...and as prototypes too.
http://en.wikipedia.org/wiki/Stellarator
Anyway, basically what I know about this is that stellarator designs avoids lots of the problems that are present in Tokamak - namely, degrading of the reaction chamber due to escaped neutrons. A fusion reactor using stellarator instead of Tokamak would, in effect, last forever since the material does not become radioactive.
Especially the Germans have been researching this stuff a lot, however, most of the big money is currently in Tokamak designs, including ITER. Which is kinda a shame - since we're not in the Manhattan Project-type "if you have 3 designs and think one of them might work, build all three, here's the money"-situation..so these nice ideas may only be developed further if Tokamak fails to become viable..
Computers are useless. They can only give you answers.
-- Pablo Picasso
For the $1,000,000,000,000 Monkey Boy will spend in Iraq we could have put solar collectors on every home in America for free. So they finally figure out how to make fusion work. Energy will still be monopolized by the power companies and you'll still be paying through the nose. And if you try to do anything about it they'll call you an enemy combatant and send you to Guantanamo. There is no technological fix. There is only a political fix.
Blast radius my foot. A fusion reactor is immensely safer than a fission reactor. Furthermore, fission reactors are really very safe (far safer than, say, oil refineries). Even Chernobyl was primarily a /chemical/ explosion (although caused by problems with the reactor), which happened to scatter radioactive debris over half the globe. A chemical explosion at a fusion plant would scatter hydrogen. Oh boy. Even the unstable isotopes of hydrogen are still light enough that they would float to the top of the atmosphere and escape into space in very little time. A fusion reactor is not a controlled H-bomb. Unlike a fission reactor, which requires a carefully tuned reaction to walk the knife's edge between dying out and going critical, the hard part with fusion is keeping it going. Fusion is very fussy. If the density, and the temperature, and the composition of the plasma are not just exactly right, then reaction dies out in a fraction of a second, the time it takes to exhaust the really tiny amount of fuel that is available to it at any given time. To keep it going, you have to keep feeding it more fuel, as well as carefully tuning things. If there were even a very very tiny explosion, the worst it would do is damage the devices tuning the plasma's parameters, and then the reaction would die out. Even if the fuel feeders went crazy and started flooding hydrogen in as fast as they could, it would still just die out. There is no way that the reactor, even in an undamaged state, could bring enough hydrogen to the needed density and temperature quickly enough to cause a thermonuclear explosion even on the scale of a pipe bomb. So, I say, blast radius my foot, unless you want to compress the researchers down very very small and put them inside the plasma itself.
Researchers are not involved in corner cases that might never happen. Nor are they worried about reliability yet (in the sense of preventing another Chernobyl, as opposed to the sense of very little downtime). They are just trying to get the blamed thing to produce enough energy to sustain itself, with some left over. (Although, if you're feeling pessimistic enough, you might call that a corner case that might never happen!)
I agree that we need to get a lot of funding to fusion research, but throwing money at the problem won't necessarily solve it. It is a very hard problem. Furthermore, we'd need not just one crazy (I presume you refer to the office of the President), but a whole bunch of crazies (half of Congress), because Congress makes the budget.
SIGSEGV caught, terminating
wait... not that kind of sig.
That might be so, but it certainly isn't economical, otherwise we would already have all our energy from renewable sources. Furthermore, very few renewable sources of energy shows any sign of promise in the short term, although solar certainly seems interesting once someone comes up with a "breakthrough". Oh, and we could build more dams, they can certainly be profitable, but often takes a huge toll on mother nature.
Actually, centralized makes a lot of economic sense. There is only one way of generating power that is at least potentially profitable at a small scale, and that is solar cells. But even here, you get economic benefits by simply aggregating them in a small area, which simplifies maintenance and infrastructure. Nuclear just doesn't scale down at all, and everything else, is simply more efficient at a larger scale, whether it's wind-turbines, dams, wave-turbines, geothermal, waste energy from industry, burning of garbage or methane from a landfill, or even gas, diesel, or coal. If you don't believe me, try putting up a small propeller in your backyard, and compare the $/watt of this to a typical 100 meter wind turbine, or to a huge turbine farm with 100 meter turbines. Or compare the $/watt of a small waterwheel to the Hoover Dam. Or compare the efficiency of a diesel-generator you can afford, to one that you can only afford to rent, or to one that is able to power a whole city. These things might scale down, but certainly not in an economical way.
This is certainly a valid criticism for fusion power research. But I hope you don't seriously believe that just because you can't have it today, we should stop researching it. The benefits of such a technology would be incredible, and the money we spend on it is not that much. Still, one can debate whether pouring money into tokamak research is justified given its track record so far, This, however, is not a tokamak, and as such is a potential theoretical breakthrough, even if it might be an unlikely one (I'm not qualified to judge that).