I'm not sure what you're argument is here. As you did point out, when U-238 has an additional neutron introduced, it becomes U-239 which decays into Neptunium-239 which in turn decays into Plutonium (Pu-239).
I'm getting the sense that you're only arguing with the dumbing-down I did for those who aren't familiar with things nuclear.
My point is really quite simple. Yes, under neutron bombardment U-238 will convert to Pu-239, but not in nearly enough time to become part of the fission/fusion reaction, as you claimed it would in post #58.
--Boot Hill