Re: Fusion Power

From: George Murphy (
Date: Fri Jun 06 2003 - 12:43:59 EDT

  • Next message: Iain Strachan: "Re: Fusion Power"

    Lawrence Johnston wrote:
    > Hi, Iain -
    > I'm happy to get info from people who have worked in the fusion
    > business.
    > In your response below, you assume that Li^7 is stable, and is
    > the fuel for more tritiuim. But, as George Murphy and the
    > original Hutchinson article pointed out, the stable isotope is
    > Li^6. If it were Li^7, you might indeed get more neutrons in the
    > output, and have a Litium chain reaction going to produce
    > tritium. But the reaction
    > Li^6 + N -> Li^7 -> He^4 + H^3 is the one George
    > indicates.
    > Li^7 is extremely unstable, with a half-life of maybe 10^-12
    > seconds. *
    > So what we need then is an estimate of the efficiency of this
    > process for regenerating tritium, taking into account the losses
    > of neutrons in the reactor vessel, and the cross section of Li^6
    > for the above reaction. It must be much less than 100%, leaving
    > the need for some outside source for most of the tritium, such as
    > fission reactors.

            Another note from the old _Project Sherwood_ (p.43) speaking of possible Li

            "Molten lithium was originally considered; from recent studies, liquid lithium
    nitrite appears more promising in many respects. The small fraction of neutrons lost
    (through absorption in structural materials or the nitrogen of the nitrite) can be
    compensated by (n,2n) reactions in some material such as beryllium in the blanket."

            I don't know exactly what reaction was in mind here but it suggests a way to
    deal with n loss.



    George L. Murphy

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