There's an old joke about Jesus raising Lazarus from the dead by first turning him into a loaf of bread - as Jesus explains to the awe-struck crowd, the miracle was not that he rose, but that he was turned into bread.

Same here. Nuclear power is easy . . . if you have the enriched uranium to work with. I'm guessing one of the levers of power the Empire holds is the legal authority to refine the raw ore (shades of what's happening with the nuclear proliferation treaties in modern times). Interstellar travel being as it is, Anacreon is probably totally dependent upon fuel shipped in from somewhere else in the Empire.