----- Original Message -----
From: "Stephen A. Lawrence"
Since boron is way lighter than iron (the "man in the middle" at
the bottom of the energy trough), why isn't splitting boron an
energy-negative reaction?
The short answer which is easiest to understand is: because an
alpha particle, 4He is an unusually stable nucleus, when a proton
impacts 11B with enough energy (threshold 1.8 MeV), then three
alphas are a favored result - and with the large advantage of no
(very few) neutrons - it is a highly desirable reaction which
gives off almost 9 MeV equally divided; which energy represents
the "excess" mass-energy in the boron isotope nucleus compared to
three alphas.
Wiki has this on aneutronic fusion...
http://en.wikipedia.org/wiki/Aneutronic_fusion
BTW they did not emphasize enough that the reason that lack of
neutrons is important has little to do with radioactive waste and
activation of the reactor, etc. and that the paragraph on "Power
Density" applies only to the Tokomak and not to an IEC device.
The problem is that because it is lightweight and neutral, the n
carries away so much energy (from the D+T reaction zone) i.e. out
of the reactor itself - that the reaction cannot self-sustain for
very long after ignition. 11B + p could self-sustain indefinitely
in the proper reactor. Consequently - although it takes a lot more
input energy to ignite boron than T+D, from there on, following
ignition, it takes less energy to sustain and operate the reactor
over time, and direct conversion to electricity is possible -
while the T+D has to be continually pumped and direct conversion
is not possible.
