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Just a thought regarding nuclear fusion

  1. Jul 25, 2004 #1
    I'm a noob in this lol, but a thought just cross my mind. If in nuclear fusion, we require high temperature to overcome the EM repulsion of nuclei, is it possible to bypass this and simply make use of the nuclear force, or color interaction which holds the nucleus together. Is it possible to amplify this color interaction so that fusion takes place instead of just holding it together.

    And also, if I'm not wrong, cold fusion has not yet have a theory behind it, could this be a possible theory?

    Also, its kinda off topic but I've got a question regarding beta decay.


    3H (can't do superscript, its tritum as opposed to 3 molecules of hydrogen)
    ------>4He (again...) + e

    Why is it that in one side of the equation I've got one electron and the other I've got 3? I know that Beta decay causes neutrons to decay into a proton, electron and neutrino, which explains the presence of one out of the 2 difference in electrons. What about the other 1, where did it come from?
  2. jcsd
  3. Jul 25, 2004 #2


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    That would be a great idea, if we only knew how to create an manipulate the strong (or color) force. We know that quarks generate gluons by the scad, and the gluons carry the force, but both quarks and gluons remain locked up in the hadronic particles. We have no neat trick like electromagnetic induction to convert motion into strong, or weak, force.
  4. Jul 27, 2004 #3
    Are you suggesting that, provided we find some device to create, say a constant color force of a given (wise) shape, then we might be able to extract energy at a scale beyond usual nuclear energy (fission and fusion), exactly as EM forces are a scale beyond chemical forces ?

    We could hope that progress in QCD and/or the various string theories (which emerged from QCD historically) will provide some day such a device !
  5. Jul 29, 2004 #4


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    The equation refers only to the nucleae, not the atoms. Also, I think you forgot the neutron on the left side.

  6. Jul 29, 2004 #5
    No, since that example is about beta decay, and not fusion, he did not forget a netron. But it should read (treat numbers as superscripted):
    3H --> 3He + e-

    misogynisticfeminist, there are no electrons on the left side, only the tritium nucleus. That is composed of one proton and two neutrons. In the beta decay process, one of those neutrons becomes a proton, releasing an electron and an anti-neutrino. The resulting helium-3 nucleus is composed of two protons and one neutron. There is only one electron involved, the one on the right side, which came from the decay of the neutron.

    As for your first question: Unlike the EM force, the strong force is short-range. Fusion occurs precisely because the strong force takes over when two nucleii come suffciently close. But to get them that close, they must first overcome the electrostatic repulsion between them. If we could manipulate the strong force directly, this would have been much easier. But we can't, at least not yet.
    Last edited: Jul 29, 2004
  7. Jul 31, 2004 #6
    not really, what do you mean though?? Cos' I'm new at this, what is a wise shape? I actually meant that can we can amplify the colour interaction, maybe extend its range so that nuclear fusion can take place without the insane temperatures?

    Oh yea, thanks for answering the question regarding beta decay. And would fusion reactors be less pollutive than fission ones? If we one day manage to find a way to control the strong force? The chances of a meltdown would depend on the methods used, but there's no nuclear waste involved, unlike in fission as we do not want any daughter nuclei but just the energy. Am I right in saying that a fusion reactor would not produce any nuclear waste?
  8. Aug 1, 2004 #7
    Yes and no. The only byproduct you get is helium. It's not radioactive, so it's preety much safe. But there's still the question of what to do with all that helium. Dumping it into the atmosphere may not be the best idea, unless we're only talking about small amounts.
  9. Aug 4, 2004 #8
    Well, amplify or extend the colour interaction (wich is the fundamental strong interaction, residual strong interactions hold protons & neutrons together) is impossible (sorry, mate). Nature says: "this is it, take a hike." You can't reach in because of the short interaction range.
    Fusion is most likely to be produced first in a tokamak configuration reactor, it's way way different than the fissionreactors. Meltdown is not a possibility, worst thing that imo could happen is that when the plasma reaction swings out of control, the interior of the reactor gives way immediately disturbing the EM fields containing the plasma and the plasma is absorbed by the surroundings with a possible bit of corrosion to go with that.
    the Deuterium-tritium reactor produces stable helium, no problem, dump it (rises in atmosphere, done & done), other solution would be to collect it and sell it for a nickle.
    However the interiour of the reactor gets a pounding as the high-energy neutrons fly right through the plasma to hit the walls of the chamber. These enormous neutronfluxes radioactivate the chamber's interior wall. That is waste eventually, though many many times less problematic than used fission feul.
  10. Aug 4, 2004 #9
    You never know, maybe we can produce deconfinement, and then... Anyway, confinement is not proven !

    Yet, I agree with Antimatter.
  11. Aug 5, 2004 #10
    You still get meltdown, you just don't get a nuclear explosion along with it. As long you have containment, you don't have a problem. If containment is lost, you get a rapid shutdown of the fusion reaction, as the temperature and pressure of the plasma drop below the minimum required for fusion. But you also get millions-degrees-hot plasma leaking in all directions, vaporizing anything in its way. What you want is a reactor casing made of a material with a high melting point and heat capacity. If you put enough of that stuff around the reactor, you can contain the meltdown inside. You also need some way for all the vapor to escape, or a casing that can withstand the resulting pressure, otherwise the reactor would explode from the pressure buildup.
    Yea, that's what they said about car exhaust when cars were developed, and look where that got us. Once the amount of dumped helium passes some treshold, you may get undesirable environmental effects. We just don't know enough about how earth works to say its definitely safe even in large quantities.
    Well first, the resulting radioactive isotopes decay rapidly. Second, you can minimise this by selecting the proper materials. And third, if you use lithium as coolant, most of the neutrons will react with the lithum giving off helium and tritium. The latter is then used to fuel the reactor (along with deuterium).
  12. Aug 8, 2004 #11


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    In fact, there are some proposed designs that use liquid lithium as the interior wall of the reaction chamber. Held in place by the same type of magnetic field that pinches the plasma, this interior surface would contiually flow by, producing tritium to be plasmasised and fed into the reactor.
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