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  • #403
    AvatarTransmute
    Member

    I’m not a nuclear physicist so my knowledge on this is limited, from what (little) I have read p-Li7 fusion would be aneutronic and produce nearly twice as much power per mol as p-b11 fusion. So what is wrong with p-Li7 fusion?

    #2020
    AvatarJolly Roger
    Member

    Transmute wrote: I have read p-Li7 fusion would be aneutronic and produce nearly twice as much power per mol as p-b11 fusion. So what is wrong with p-Li7 fusion?

    According to

    http://www.faqs.org/faqs/fusion-faq/section1-physics/

    p-Li7 is aneutronic only 20% of the time and yields a neutron in an endothermic reaction 80% of the time.

    p-Li6 is better, as it is entirely aneutronic. but p-B11 is also, and produces more energy.

    #2021
    AvatarTransmute
    Member

    Li6 then (which I think I what I originally meant, but never mind that) why is it inferior to boron?

    #2024
    AvatarJolly Roger
    Member

    On the Fusion FAQ page I previously cited it states that the p-Li6 reaction gives up 4.0 MeV energy, whereas the p-B11 reaction gives up 8.7 Mev energy, more than twice as much.

    However, according to

    http://home.earthlink.net/~jimlux/nuc/reactions.htm
    (“Nuclear Reactions of Interest”.)
    there is a secondary reaction. p-Li6 produces He3 and He4. He3 further reacts with Li6 to produce 16.9 Mev energy.

    The p-B11 reaction requires a higher operating temperature. I do not know how much higher.

    As x-ray production (and x-ray cooling) is proportional to the square of the charge (Li=+3, B=+5), the Boron reaction produces 25/9 more x-rays than the Lithium reaction, almost 3 times as much. However, Dr. Lerner has stated that the Magnetic Effect may mitigate that problem.

    The Li6:Li7 abundance ratio is only 8:100, but isotopic separation is said to be not difficult.

    I think that Lithium-6 should be investigated as a potential alternative fuel, and not dismissed outright.

    #2055
    Avatarrashidas
    Participant

    Excuse my ignorance but are there alternatives to boron as a fuel for focus fusion? In case of boron scarcity can isotopes of beryllium, carbon or nitrogen be used instead?

    #2056
    AvatarTransmute
    Member

    Boron is not scarce

    #2304
    Avatarsamitch
    Member

    has anyone heard about this type of fusion

    #2367
    AvatarTransmute
    Member

    I think I found the reactions I was looking for:
    1. p + Li6 -> He4 + He3 + 4 MeV
    2. 2He3 -> He4 + 2p + 26.2 MeV
    or
    3. He3 + Li6 -> 2He4 + p + 16.9 MeV
    Total = 20.9-30.2 MeV

    Far more energy productive then p+B11, the only problem maybe that it require multiple steps which might night happen in a F2 reactor if its pulse time is too quick.

    #3634
    AvatarTasmodevil44
    Member

    I have also raised the possibility of using lithium as fuel. But skeptics such as Jimmy T and others like to point out the fact that p-B11 is the so – called ” Holy Grail ” of fusion. There’s no doubt that the p-B11 reaction has it’s advantages, which is why Lerner chose it above all other aneutronic reactions. However, I was thinking more along the lines of lithium as a partial supplement rather than a complete substitute for boron. If fuels like He 3 or Li 6 can be made to ignite at lower temperature and pressure, it may help to preheat the plasma and give p-B11 a little extra more energy boost than the electric power supply alone can provide.

    #3635
    AvatarTasmodevil44
    Member

    The pulse duration in picoseconds may indeed present a problem, however. These multi – step reactions helping to kick – off the next reaction all have to occur within only 6 picoseconds or less.

    #3643
    AvatarTasmodevil44
    Member

    But then again, if a fuel that first ignites at lower temperature helps to further preheat the fuel prior to boron ignition……then might that possibly extend the available nuclear reaction time longer than only 6 picoseconds ?

    If so, it might open a window of whole new possibilities for many more sucessive reaction events to take place.

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