Of the operating set of reactors today, what percentage are those vs., say, Thorium?
https://en.wikipedia.org/wiki/Thorium_fuel_cycle
https://en.wikipedia.org/wiki/Uranium-233#Weapon_material
"A declassified 1966 memo from the US nuclear program stated that uranium-233 has been shown to be highly satisfactory as a weapons material, though it was only superior to plutonium in rare circumstances."
Many nuclear energy opponents require absolute nuclear proliferation safety.