Uranium (or other radioactive materials) don't directly generate much electricity - they mostly generate heat. Most nuclear power plants generate electricity by

Uranium (or other radioactive materials) don't directly generate much electricity - they mostly generate heat. Most nuclear power plants generate electricity by having that heat turn water into steam, which is then used to power steam turbines that actually drive the generator coils. Of course, in order to do this, you have to be able to pump water into the reactor to be turned into steam, and that pumping requires power. So yes, while you definitely need power for the safety/management equipment, the major bootstrap issue is almost certainly all of the power necessary for the pumps.