[extropy-chat] transmutation of uranium in solution

[Keith Henson]

At 03:57 PM 2/18/2007 -0800, you wrote:
> > bounces at lists.extropy.org] On Behalf Of Keith Henson
> > Subject: Re: [extropy-chat] Space elevator numbers III (2)
> >
> > At 07:06 PM 2/16/2007 -0800, spike wrote:
> >
>...
> > >Now we need to control all neutron sources.
> >
> > Only the big ones.  If you want 24 kg of Pu 239, it takes a tenth of kg of
> > neutrons to make it...
>
>Ja, I wasn't concerned about Simone Bar Sinister creating an entire critical
>mass herself, but rather anyone with a modified light reactor making a few
>grams.

Don't understand that.  Less than a critical mass isn't nearly the danger 
of a critical mass.

>There is a prevailing notion of getting African nations to start
>light water reactors, thus draining the world's uranium without creating
>plutonium.

I really don't get that.  All uranium reactors make plutonium.

>It looks pretty reasonable that such a reactor could be modified
>to make some plutonium, which leaks to the black market, which is collected
>by the bad guys.  Even a few grams could be used to create panic, if the bad
>guys knew what they were doing.

It isn't *just* plutonium which can be extracted from spent fuel.  This 
stuff might be pure enough (low enough in Pu 240) to build gun type bombs.

>Keith if understand your notion correctly, the uranium ion in solution is
>sent near a neutron source.

The solution is pumped through a power reactor.

>he difference between the usual methods and
>this is that the uranium ion would be free to recoil, which would take some
>of the energy of the neutron.

No, that's not significant.  The U238 absorbs a neutron just like it would 
in the metallic state and decays to Pu 239.  It would probably be best to 
use depleted uranium to avoid contamination with the Pu isotopes you get 
from the fairly rare decay of the U236 that does not fission.

>My initial thought was that there would be
>insufficient energy left to have two beta decays, perhaps you would get only
>one beta and end up with neptunium.  Unfortunately for this planet, if you
>look up the nucleon energies of uranium and plutonium and the betas, there
>is enough energy left after neutron absorption and kinetic energy carries
>off about 0.4% percent.  This is bad enough, but an energy balance also
>shows that neptunium formation doesn't occur (assuming I am doing the energy
>balance correctly, which isn't a guarantee).

The fact the U is in solution does not make much difference.  I don't know 
if neptunium absorbs another neutron or not, but taking it out of solution 
along with the Pu is probably a good idea.  I would imagine a pumping rate 
such that the exposure was under a minute before the Pu was picked out.

snip

Keith