Nitpick: fast neutrons don't cause fission in uranium-238, they cause it to transmute into uranium-239 [1] which is a much less stable isotope with a half life

Nitpick: fast neutrons don't cause fission in uranium-238, they cause it to transmute into uranium-239 [1] which is a much less stable isotope with a half life of less than 30 minutes before it decays into neptunium-239. [1] https://en.wikipedia.org/wiki/Isotopes_of_uranium#Uranium-239 https://en.wikipedia.org/wiki/Isotopes_of_uranium#Uranium-23...