Yup. A significant amount of the fissile material in Europe used to come out of Russia. France, who is commonly held up as the arch-defender of nuclear power, is now fighting basically colonial wars in Africa for this stuff. There's a finite amount of it, it's costly to extract, costly to refine, costly to transport. Even before you've generated a single kilowatt of power, you've already done a lot of damage to the environment just for the fuel.