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Science

Fusion Via Persuasion 26

Posted by Hemos from the pollution-free dept.
SEWilco writes "Researchers are making progress toward causing muon-catalyzed fusion. A muon allows creation of a tritium-deuterium molecule, then forces the nuclei together. This is fusion by atomic-level trickery rather than the brute force approach of simulating the center of a star. Progress is being made on the two lab-level problems in the process; if those are solved then a muon-catalyzed fusion plant becomes an engineering problem."
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Fusion Via Persuasion More

Fusion Via Persuasion

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  • unsubscribe (Score:1)

    by Anonymous Coward
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  • Why is this not on the main page? This is a really interesting article. We need discussion.

    What's the deal?

  • Persuasion and trickery is usually preferred over force (by me anyway).

    Would this method also be less "lossy" as far as being able to channel a higer percentage of the resulting energy into work, instead of loosing it as heat or (pick an energy type)?

    Visit DC2600 [dc2600.com]

  • Why is this not on the main page? This is a really interesting article. We need discussion.

    This may be one of the most important articles I've seen in a while, assuming the information is correct. The ability to fuse hydrogen at 3 Kelvin goes way beyond "Cold fusion". Maybe "Freezin' Fusion"? Also the fact that the fusion works best at 1 ev is nothing short of astounding.

    I really wish there was some way of moderating these back page topics up to the front page. Maybe one day, if moderation ever gets fixed.

  • The problem is, how could we contain the energy produced by fusion and keep it cool? I mean, I can't recall anything I've read that didn't assume a huge amount of heat when fusion occurs.

    Am I just out of the loop on this one?

  • I thought this method worked at 3 Kelvin. Isn't that cold enough?

    Anyway, you are restating my point. Massive amounts of energy from "classic" uncontrolled fusion are lost as heat and light.

    Example: Thermonuclear bomb is used to dig a hole where a city sits now. However, so much energy "leaks" out that the hole is much smaller than if all of the energy was used for hole blasting (even if the bomb is buried really deep).

    Theoretical example: old-school plasma type thermonuclear furnace is created for production of electricity and hi temp. product fabrication. However, heat is lost that is not used to spin a terbine or melt exotic materials and must be carried away to the cooling towers.

    So, my question is more along the lines of: are we going to see more energy per reaction going into the intended purpose of the facility, or is it going to be just as lossy as plants are now?

    Visit DC2600 [dc2600.com]

  • Maybe I'm missing something here, and I am NOT a nuclear physicist, but I don't see any way that this can be a sustainable source of energy. From the article:

    • "In order to get a decent yield, the energy of the muonic tritium must be kept very low, about 1 electronvolt (eV), as it approaches the deuterium nuclei."
    • "The researchers fired their beam of 1 eV muonic tritium at concentrated deuterium condensed onto gold foil, and chilled the whole set-up to 3 kelvin."

    So you need an incredibly cold environment for this to work, right? But if the goal is to PRODUCE energy out of all this, as soon as it starts to really produce energy, the whole thing gets too warm to continue the fusion!?! If anything, wouldn't it take even more energy to power the equipment to keep things cool enough to sustain the fusion?

    The only possibility I can imagine is that this fusion results in an increase in potential energy in the fused particles and that there may be a way to physically transport them someplace else where they can release the potential energy as kinetic energy. (Something along the lines of a heat pump?)

    Could someone with a better understanding of nuclear physics please shed some light on this?

  • Sorry, guess I wasn't making myself clear.

    Yes, the fusion is cool. But the energy produced isn't, right? So how do we contain the energy and use it, other than using a turbine system.

    IMHO, that's where the loss comes from. Turbines are pretty much made with the idea that they won't be terribly efficient, but they'll produce a lot of energy anyway.

  • Yes, the fusion is cool. But the energy produced isn't, right? So how do we contain the energy and use it, other than using a turbine system.

    Hummm... I don't know. AIGGGHHHHHHH (bridge troll throws me into the valley of eternal doom or whatever it was in Monty Python)

    Would be interested in knowing that too.

    Visit DC2600 [dc2600.com]

  • Re:Sustainable? (Score:1)

    by Anonymous Coward
    It may not be that bad. The mu-T could be cooled a few meters from the reaction site. Also keep in mind, the mass reacting is tiny, while the fridge is a good solid lump of gear. You're right that the cooling stage is an inefficiency - maybe a show-stopper. But any progress on the basic reaction is a gain at this point. The last I heard, the D-D or D-T reactions could produce at most 1/15 of the energy required to create the muon. Increase *15 the probability of the reaction, and then we'll talk whole-system efficiency.
  • The only way i can see how you get energy out of fusion is by heat... (unless you find a way to have lots of tiny hydrogen bomb type explosions in a combustion engine :) ) so heat produced is not "lost". Most traditional power stations do nothing but produce heat which is then converted to electrical energy, usually via heating steam to power a turbine.

    This still leaves us with the problem mentioned many times that according to the article we need a cool environment to run this in. But whatever, cool idea, cool experiment!

  • Someone didn't get enough coffee (Score:3)

    by the_other_one ( 178565 ) on Thursday August 31, 2000 @07:24PM (#813578) Homepage

    The source listed at the bottom of the article Physics Review Letters (vol 85, p1674) is incorrect.

    It looks like the correct source should be Physical Review Letters -- August 21, 2000 -- Volume 85, Issue 8, pp. 1642-1645

    The Abstract is available here [aip.org]

    You can download the .PDF or gziped PS version of the article for $20 US but I'm not that interested.

  • What sort of energy do you think you might be able to harness for electricity? Fusion produces heat and light (case in point: The Sun).
  • The first time I heard of this type of fusion was when I visited a friend of a friend who is a physicist. He is working on cold fusion but showed me a printout of the Princeton fusion FAQ. I read pretty much most of it and it indicated that there was another form of cold fusion, namely this muon-catalyzed one. I asked him about it and he said that it went nowhere because the muons were extremely short lived. I think this type of fusion was proposed by Enrico Fermi.

    Anyway I tried to find the Princeton Fusion FAQ but all I could find was a snippet [pppl.gov] of it that someone who does Q&A posted at Princeton.

    Yes someone please repost this story on the front page! I found it completely by accident.

  • yes yes, I know.

    I've spent so long studying turbines, I guess I'm just tired of them.

    I *would* like to advocate a new paradigm though. If I only knew which one. While turbines work, they really do let a lot of energy get wasted.

  • Re:Sustainable? (Score:4)

    by AdrianG ( 57465 ) <adrian@nerds.org> on Friday September 01, 2000 @04:50AM (#813582) Homepage
    I think the low temperature was used because it is easier to collect useful data without letting other factors pollute the results. Muon catalized fusion is considered a cooler fusion mechanism because it can, in theory, produce useful output at temperatures of 1000 C or less. It cannot be used to produce useful amounts of energy (i.e. more energy than you put in) at the extremely low temperatures cited in the artcile, but it might produce useful experimental results.

    Adrian

  • In biology, fusion refers to the merging of two gametes, basically, Fusion through persuasion means something else. Bio geeks, please don't laugh too hard.
  • Are deuterium futures traded on any of the commodity exchanges? heh.
    --
    man sig
  • I wonder. Since muons are like heavy electrons, if either of these techniques can be used in conjuction with a fusor (http://fus.x0r.com [x0r.com]). Which was able to get fusion in the 1930's (i believe). But it sucked up way more power than it produced.
  • Hey, at 3K it might even work in Canada! ;)

  • Do it in your home? (Score:3)

    by ka9dgx ( 72702 ) on Sunday September 03, 2000 @09:23AM (#813587) Homepage Journal
    What if we just take a nice palladium or nickel target, put it in an aqueous solution of lithium hydroxide, and apply a voltage differential to it? This would cause the metal matrix to load with the available lithium and/or hydrogen ions near the surface. We then just wait for a muon to happen along (cosmic rays, etc)... and watch what happens (aneutronic nuclear fusion). It might happen more frequently at altitude, say Denver or Boulder Colorado. It would be less likely to happen at lower altitudes, and might be very sensitive to impurities (aka Poisons) just like the first nuclear fission reactors were. Similar situations have happened with novel physics before, for example, If it weren't for stubborn engineers from Westinghouse insisting on more room for fuel, all the work at Hanford during WWII would have been waste. It was only later learned that certain products of fission reactions act to poison the reaction.

    All the above could be done... any competent chemist could do it, no physicist required. Even the home brew experimenter can get into the game.

    It might be interesting to consider the case of this happening with in a metal matrix that has just been so loaded, then compressed quite a bit, using something like a diamond anvil press, etc. It's quite possible it could go BOOM in a big way, converting some mass directly to energy. (If this were possible though, one might expect certain three letter Government agencies to get into the act of surpressing the technology).

    That's my two cents for the day.

    --Mike--

    PS. Why didn't I see this story on the main page?

  • Muon catalyzed fusion uses the muon, which is essentially a heavy electron, to produce fusion at near room temperatures. As others have pointed out, this effect has been experimentally observed since the 50's, mostly as a nusiance effect in particle accelerators. Of course, cold temperatures are relative. 1/40 of an eV is about room temperature, so 1 eV is pretty darn hot.
    It works because the muon is some 207 times heavier than the electron, and the math works out that if you put it around a proton, making muon-hydrogen, the average distance of the muon from the proton is about 200 times closer than that of the electron in a similar state around a proton. This means that the muonic hydrogen atom itself is about 200 times smaller than the conventional hydrogen atom. It takes a lot less energy for other hydrogens to get close to the small atom (the couloumb barrier is much thinner), so you can cause fusion at much lower temperatures, less energy is needed to get the particles close enough to fuse.
    The problem with muon-catalyzed fusion is that it takes muons, which are incredibly energy-expensive to produce. The efficiency of the particle accelerators needed to make them is miniscule. Less than tenths of a percent. No free lunch there, although there are a few people looking into its viability, especially as a catalyst toward more efficient fission reactors.
  • There's enough deuterium in seawater, but where will the tritium and muons come from? Even raiding all the H-bombs in the world for tritium would not get you that much, and tritium production via neutron bombardment of heavy water is way expensive.
  • The key point to MuCF is that the muon is not consumed in the reaction but just catalyzes it. This means, in principle, a single muon could catalyze many fusion reactions. Hence, the big interest. Contrary to the other postings, MuCF does work at high temperatures, just not as efficiently. And since efficiency is the goal here, low tempatures apear to be the place to start. There are four main problems preventing MuCF from becoming practical: 1) as previously pointed out, making muons is highly inefficient. The cost is ~$2000/hr for a 1mA beam. 2) The lifetime of a muon is only about 2uSec. 3) The muons diffuse out of the target and are lost. 4) Probably the most important problem, the muons are captured by the helium that results from the fusion reaction. Once captured the muons are not availible to catalyze further reactions. I believe the number is something like an average of 200 fusions before the muon is caught. The most important problem to solve is number 4. If the number of reactions before capture is raised then the other problems can be solved mainly by increasing the Deuterium target density. Hope this helps.
  • Basically you have two ingredients (muonic tritium and a deuterium nucleus) and you need to bring them together very carefully with exactly the right sized bump. If you do then, with luck, they go bang, producing an enegetic alpha particle, an energetic neutron and an energetic muon. You would then need to

    a) recover the energy from the alpha particle
    b) use the neutron to breed more tritium (lithium blanket
    c) catch the muon and reuse it (quite a lot of times)

    Probably the way to do this is in quite high vacuum, so that you can have cold beams of uT and D atoms coming in and reacting, largely unaffected by the energetic reaction products flying outwards to be caught somewhere. The hardest part of this would be stripping the muons off the alpha particles, separating them, cooling them and recycling them quickly enough and with enough efficiency, but it might be possible.

  • This is, unfortunately, neutron-rich fusion -- ie.: a free neutron is produced as part of the end result -- and will, unfortunately, result in the need for a "radiation blanket" around the core of the reactor, and this core will ultimately, thought the absorption of those free neutrons, become radioactive over time.

    Disposable muon-presuaded fusion reactors? Great. More nuclear waste.

    I can see this as being beneficial, and certainly the radioactive material won't be nearly as nasty as the shit coming out of "modern" fission piles. (Remember, the first working fission reactor was built back in the 1920's a the University of Chicago...under the bleachers at the football stadium.) My concern, however, is that this is going to be seen as long-term solution, when we should be looking for a solution for hydrogen-hydrogen fusion which will not have the problem of those pesky free neutrons.

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