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

[Anders Sandberg]

Spike:
>> 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.

I don't think the peak is that fine grained. I would expect the uranium
atoms (or rather, uranyl ions) to have a Maxwellian distribution with a
mean at sqrt(3*T*k/m). So for T=300 K, k=1.3805e-23 J/K and
m=340.90/6.022e23=5.66091e-22 I get 4.68485696 m/s! So the target is
almost standing still. Neutron energies can apparently be in the MeV
range, which would make the difference practically nil.


-- 
Anders Sandberg,
Oxford Uehiro Centre for Practical Ethics
Philosophy Faculty of Oxford University