[extropy-chat] Nuke 'em

[Robert J. Bradbury]

On Sun, 23 Oct 2005, Greg Burch wrote:

> These issues are weapons proliferation and waste storage.  Both
> seem to call for structures of social control about which liberty lovers
> and skeptics about government power and efficiency should have deep
> misgivings.

Greg, there may be a problem with "waste storage" currently but
there isn't in the long term.  Nuclear transmutation is a very
well defined science.  Just as all of the radioisotopes currently
used in science and medicine can be manufactured it is possible to
take radioactive isotopes and transmute (or breed) them into
non-radioactive isotopes.  There are however mass/cost issues
associated with the process however.  All current "waste" consists
of a small fraction of radioactive isotopes and a large fraction
of non-radioactive isotopes.  Ideal (less expensive) transmutation
strategies require relatively "pure" streams of specific radioactive
isotopes so they can be subjected to specific transmutation strategies.
One could, in theory, use the same methods (centrifugation) that are
used for uranium enrichment to separate out the specific radioactive
isotopes but a relatively complex (and presumably expensive) infrastructure
would need to be built.  One would also have the electricity cost of
running such facilities.

Now, this entire problem shifts significantly once one has nanotechnology.
Nanomedicine Volume 1 discusses several methods for sorting materials
based on atomic weight -- from "single proton (neutron) massometers"
to nanocentrifuges with capabilities significantly greater than macroscale
centrifuges.  Since these could be constructed in highly parallel systems
and would be very efficient the costs for separating the radioactive from
the non-radioactive elements/compounds would be relatively inexpensive.
You feed the radioactive materials into reactors or accelerators and
transmute them into non-radioactive materials.  Voila -- no "waste".

I look at the Yucca Mountain debaate as being rather stupid because
sometime in about 30-50 years I think they are going to start taking
the waste out of the storage facility and start transmuting it into
non-radioactive materials.

It is worth noting that LANL has an active research effort involving
nuclear waste disposal via transmutation as do several groups in Europe
and Russia.  The work is not however very high profile or funded very
well because of the separation cost/methods problem.

Regarding the proliferation problem, obviously the best solution is
to avoid transporting the materials as much as possible.  Presumably
one would like to concentrate the uranium and dispose of waste
materials "on-site".  You can't easily do that now but you could
do it with nanotechnology.  Alternatively you want high density
specialized sites for these activities, presumably away from major
population centers, perhaps somewhat like the petrochemical plants
on the Gulf.  I have heard people discuss the idea of electricity
transmission in buried pipelines using superconducting cables cooled
using LH2.  It is an interesting idea as one reduces electrical
transmission losses significantly while providing a hydrogen
delivery system.  It would however take a significant amount of
time and investment to construct such a system.  Ideally one
would like a nanorobot based pipeline construction system which
is fed the raw materials and digs the pipeline path and manufactures
the electric cable/LH2 carrier pipeline in situ without ever having
to dig up the ground.  This has the advantage of being able to place
the pipelines deep enough that they would not represent a threat
to anyone on the surface.

If you can make the transport of the products (electricity, H2, CH4)
cheap enough and safe enough then one can secure the production and
and waste disposal to a very high level at specific facilities and
avoid any significant impact on society in general that you may be
worried about.

There are also safety issues.  But I believe work on alternative
designs, such as the Pebble Bed Reactor [1] may be addressing these.
The Chinese may end up being the first to seriously move in this
direction [2].

Of course some of my suggestions require robust nanotechnology, but
with the announcement of the Rice nanocar [see 3] that just became
something one can more legitimately incorporate into discussions
of long term planning.

Robert

1. http://en.wikipedia.org/wiki/Pebble_bed_reactor
2. http://www.wired.com/wired/archive/12.09/china_pr.html
3. Light-driven motorized nanocar built at Rice: step toward molecular
manufacturing
http://www.foresight.org/nanodot/?p=2057
(Has some additional links not in previous posts to ExIChat including
the precise chemical synthesis steps in the Nano Letters article.)