Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: a new nuclear option?



the reason for not "just leaving the Pu-239 in with
the U-235 and continue the 'burning' process". It's been several years
(15+) since I was involved in nuclear physics, but the physics has a nice
habit of not changing! The absorption cross-section of Pu-239 is well in
excess of that of U-235. Even if it were only just the same, it would
grab a "50% market share" of the available thermal neutrons. This would
effectively raise the mass required for sustained criticality beyond that
attainable thus "poisoning" the reaction.

But if the Pu-239 captures a thermal neutron would it not then fission?
(Pardon my verbing - I don't like "fiss".) Wouldn't a higher fission
cross-section reduce the constraint on neutron economy, since the Pu
would grab a larger share of the thermal neutrons available? My guess
was that the accumulating fission products are building the barns and
poisoning criticality.

Leigh