Subject: Re: "Fundamental Limitations on Plasma Fusion Systems ..."
From: jac@ibms46.scri.fsu.edu (Jim Carr)
Date: 13 Dec 1996 15:31:18 GMT
Arthur Carlson TOK (carlson@ipp-garching.mpg.de) wrote:
:[...]
: Rider's summary of the "outlook for advanced aneutronic fuels"
: (He3-He3, p-B11, and p-Li6) was: "Thus there is very little hope of
: ever being able to produce net power with any of these fuels."
:[...]
: Among the specific systems which Rider has ruled out (in his own
: words, with minor editing) are:
:[...]
: * Transient nonequilibrium burning systems which try to produce
: enough fusion power before the particle distributions equilibrate.
: * Reactors burning advanced aneutronic fuels (He3-He3, p-B11, and
: p-Li6) in thermodynamic equilibrium, even if the bremsstrahlung
: radiation could somehow be collected and directly converted into
: electrical energy at relatively high efficiencies.
: * Reactors which attempt to burn advanced aneutronic fuels in a
: plasma which is not in thermodynamic equilibrium.
[...]
jamesl@netcom.com (James Logajan) writes:
>
>I've done some quick double-checking and it appears my suspicions about the
>use of lithium-hydride in fusion bombs is essentially correct. However,
>LiD seems to be the favored material over LiH.
LiD rather than LiH is used for some very basic reasons that you can
read about in any of the "making of" books. It is not, however, an
aneutronic fuel because the burning process involves dissociation of
the Li-6 by neutrons and subsequent DT fusion. The Li-6 is basically
a solid source of tritium for the thermonuclear burn.
>Still, I feel confident making the following assertion:
>
>* Rider's thesis is somehow fundamentally flawed because there have existed for
>many decades "advanced fuel" fusion devices. While I am not sure if they
>could be said to be in quasi-static equilibrium during detonation or not,
>Rider would appear to rule them out in either case.
I have not read Rider, but it would seem to me that one would not
characterize the detonation of a thermonuclear device, or the
equivalent with laser-induced inertial confinement fusion, as
transient non-equilibrium burning. The context of the analysis
seems to be a reactor of the tokamak or migma type.
>Of course, no one has ever attempted to extract power from a thermonuclear
>bomb, but I see no theoretical reason to rule it out.
I also don't know what has been tried, but I would not be surprised
to find such an example in the list of experiments on the DOE's
open net site. It has definitely been proposed, and the main
reason for not following that path was, IIRC, proliferation concerns.
>And inertial
>confinement mechanism using lasers, e-beams, or ion-beams should be able
>to replace the fission trigger.
There are those who claim that the LIF proposed at LLNL is there
to maintain certain technical knowledge about implosion and the
related theoretical issues as well as a path to fusion energy.
However, those tend to use pellets of DT rather than something
more exotic according to colloquia I have heard on the subject.
>Finally, and most significantly, if I read
>Rider's analysis correctly, a fission bomb could only hope to gain a few
>percent more energy by trying to ignite LiH. I believe the reality is that
>the trigger yields several orders of magnitude more energy from igniting
>the LiH or LiD.
The aneutronic reaction of Li6+p is quite different from the DT fusion
that results from a thermonuclear burn of LiD.
--
James A. Carr | "The half of knowledge is knowing
http://www.scri.fsu.edu/~jac/ | where to find knowledge" - Anon.
Supercomputer Computations Res. Inst. | Motto over the entrance to Dodd
Florida State, Tallahassee FL 32306 | Hall, former library at FSCW.
