Re: Nuclear heater for Expeditions
Dan Clemmensen (Dan@Clemmensen.ShireNet.com)
Wed, 07 Jan 1998 21:52:56 -0500
Eugene Leitl wrote:
>
> On Tue, 6 Jan 1998, Adam Foust wrote:
>
> [...]
>
> 1) Nanotechnology is hypothetical.
True. but the original question was (more or less) "can we build
'mister fusion'?" I responded "Yes, given nanotech."
> 2) If nanotechnology _can_ work, it can do very little to increase safety
> of nuclear processes. At best, you can expect a near 100% rate of
> waste isotope reclaiming. Otoh rad damage seems to be incompatible with
> 'living' nano devices, and will certainly drastically reduce lifetimes
> of nonliving ones.
I disagree. There are two major perceived dangers of nuclear energy:
waste isotopes and massive energy release. If nanotech can permit us to
build tiny reactors, the massive energy release goes away: your "mister
fusion" is more like your gas tank than like a supertanker or an oil
refinery in this regard.
If, as you say, nanotech can permit complete recovery of
the dangerous isotopes generated
by neutron activation, then all that remains is deactivation of those
same isotopes. This is also perfectly feasible, because these isotopes
can be exposed to still more fast neutrons by recycling them back into
the fusion reactor. Most of atoms will eventually transform to stable
isotopes under additional exposure to fast neutrons. The tiny percentage
that do not can be separated (again by nanotech) and deactivated in a
tiny
particle accellerator. These processes are on balence highly exothermic,
so
the entire process of deactivation should yield a substantial net gain
in useable thermal energy. All of this hold true even if your reactor
must use D-D or D-T, both of which produce a lot of primary fast
neutrons
and therefore a relatively large amount of isotopic transformation.
Remember
that nanotech is likely to permit the use of diamondiod structural
components
instead of steel, so the reactor will be activating carbon instead of
iron:
that is, most of the resulting isotopes will be fairly benign. Now, if
nanotech
permits us to use the H-H reaction instead of D-D, we won't have much
of a problem to solve, because there are no fast neutrons generated in
the primary reaction.