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View Poll Results: Fusion worth it?

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  • Yes. keep supporting research. I think it will happen, and/or it is worth trying

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  • No. cut funding to research. I think it is just a waste of hard earned cash

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Thread: Nuclear Fusion and the neutron deprived helium atom

  1. #1 Nuclear Fusion and the neutron deprived helium atom 
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    Hello
    I am a high school policy debater, researching topics for possible cases for next year.
    This year's topic is one about increasing development of space beyond the earth's mesosphere.

    My group is planning to make a case regarding the mining of Helium-3 on the moon.

    during my initial exploration on the issue, I found that helium 3 will be used primarily for fusion reactors, which I also researched a bit.

    I all I know about fusion reactors is that:
    1) they will use the hydrogen isotopes tritium and deuterium as fuel, and lithium will line the walls? of the reactor
    2) current development is aimed at a reactor that can produce 10 times the energy put in
    3) it will almost be the perfect energy source, being safe, and economical, with very little radioactive elements involved, and with a safe helium waste
    4) they are not yet feasible, and won't be for 30< years.
    (please feel free to correct me on any of the mentioned points)

    I would like to ask this community about these questions:
    1) why is using helium-3 as fuel better than using tritium and deuterium when the isotopes of hydrogen are readily available/easily produced on earth?
    2) Are there any planned missions to moon specifically for mining helium-3 in the status quo?
    3) Would the ferrying of helium 3 from the moon in a future society where the art of fusion reactors is mastered really be economical?
    4) In your personal opinion, would it be better to pour taxpayer's money to alt-fuels or development in fusion technology?

    thank you


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  3. #2  
    Forum Ph.D. Heinsbergrelatz's Avatar
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    Okay as far as i have learned in my physics course so far, Deuterium is abundant and can be claimed naturally from the ocean etc.. But Tritium on the other hand is very hard to obtain from nature, or actually it does not occur in nature at all, so scientists need to create it using the neutrons from the D-T reaction to bombard and react with the lithium-6. I know that JET-Joint European Torus is working on fusion technology but there are 2 major difficulties in which limits the fusion technology from being used and fully active today. 1.Plasma heating and 2. plasma confinement.

    You see scientists and engineers need to pass a massive electric current in the order of A through the plasma. Of course the massive start up current heats the plasma up to the desirable fusion temperature range bBUT massive amounts of electrical power are needed to supply the start up current.

    Now containing this heated plasma at the temperature of orde 10^{8}K. The favored method is to use magnetic fields to keep charged particles of the plasma moving along a closed loop. The plasma need to not the the metal container of the torus otherwise it will lose its energy. So basically what the JET have done is set up the magnetic field in complex helix-type field, IN ORDER for the plasma particles spiral around the loop to try and make it collide with one another. So the basic idea is to try and make the plasma stable using the magnetic field so that it generates more power than it uses to keep it hot. HOWEVER the chief problem here would be that containing the plasma in a stable position is extremely challenging as particles are very energetic and wriggle out of place easily.


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  4. #3 k thx but 
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    Okay thanks for informing me about the nature of fusion reactors. but i still seek answers for my questions. do you know anything about helium 3 and fusion reactors?
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  5. #4  
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    The reason I've heard, but I should warn you that I haven't confirmed it anywhere, is that fusion using the various isotopes of hydrogen destroys the reactor walls really fast, and apparently Helium 3 doesn't do that as badly.

    . I've never been curious enough to investigate it fully. Would be interesting to know, though.
    Some clocks are only right twice a day, but they are still right when they are right.
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  6. #5  
    Forum Freshman Tachyon's Avatar
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    I'll try to answer your questions:

    1) They have been useing Deuterium-Tritium or Deuterium-Deuterium fusions so far which produce a very high energy neutron, as kojax said.
    Reaction with Deuterium and Helium-3 would only produce a proton (that can be contained useing a magnetic field and through that we could generate electricity)
    That is theoretical, in reality D and He3 would be mixed together and some D would react with another D, still producing a destructive neutron.
    Helium-3 reaction with another He-3 would only make a proton but since both have +2 charge the reaction would require alot more temperature then D-T reactions so it might be a future thing
    Long answer short, He-3 isnt better, may have some advantages in the future.

    2)No i dont think so, the story is probably a product of some sci-fi show

    3)According to some speculation, the US alone would need something like 20000kg of He-3 every year. The trip would cost A LOT and even on the moon there is something like 0.01 to 0.05 parts per million (ppm) Helium-3.
    I think that even in a future society we would have cheaper ways to generate electriicity

    4)Difficult question, even if things go well commercial Fusion is 30-40 years away (presuming it will work) Imo we should continue spending because we will need it some day surely, better to put money in so result come sooner than later.
    According to wiki, the money spent on Fusion is p-much equal to money spent on all other non-nuclear energy research put together. (might be EU stats)
    If u compare this to military spending, money put into energy pales in comparison.
    We should explore all options...there wont probably be 1 magical energysource to save all humanity
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  7. #6  
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    great thanks
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  8. #7  
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    eadgbe: fusion is readily achievable on a benchtop, but you need to put in a lot more energy than you get out. See http://en.wikipedia.org/wiki/Fusor and note that you generally only get to hear about big expensive tokamaks, which might not actually be the right approach. Talk to Doug Coulter at http://www.coultersmithing.com/ . He'll be able to tell you a lot, and point you in the right direction. Meanwhile, IMHO fusion deserves funding. As does thorium fission, see wiki. Also check out David Mackay's Sustainable energy - without the hot air.
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