[extropy-chat] Energy & Global Warming [was: Partisans and EP]

[spike]

> bounces at lists.extropy.org] On Behalf Of Keith Henson
> Subject: Re: [extropy-chat] Energy & Global Warming [was: Partisans and
> EP]
...
> 
> Some years ago it occurred to me that exceptionally high grade Pu 239
> could be made by briefly exposing U 238 in solution to neutrons... Keith


Keith I may be misunderstanding the process you propose.  I see no advantage
in creating Pu239 by having the uranium atoms in solution, but I can imagine
couple of big disadvantages.  My understanding is for neutron capture by a
uranium atom, the neutron must have a certain narrow range of momentum with
respect to the uranium nucleus.  When the target uranium is in the solid
form its momentum is zero, so the trick to facilitating neutron capture is
in moderating the momentum of the neutrons.  Uranium in solution introduces
an additional unknown: the momentum of the uranium atom.  

Secondly, it appears to me one would greatly reduce the neutron capture
probability by uranium atoms in solution because of the greatly reduced
actual number of uranium atoms.

Here's something on which I hope you will be able to educate me: if a
uranium atom is to form Pu239, the formation path is a single neutron
capture by U238 with two subsequent beta decays?  Is that how that works?
If so, are the two beta decays necessitated by the kinetic energy exchange
in the neutron capture?  If so, and you had uranium 238 in solution, it
looks to me like you would form along with your Pu239 a bunch more neptunium
239 and protactinium 239.  Would not the wider spread of kinetic energy
exchange between the U238 and the neutron cause a higher rate of single beta
decay and triple beta decay after neutron capture? 

So what is the advantage to having the U238 in solution?

If for whatever reason, this method really does produce more Pu239 (instead
of way less which is what I would expect), seems like we could do the same
trick even better with liquid U238, because of higher density of uranium
nucleii.

spike