Radioactive water and gases are released routinely. There are many accidental releases. Accidents at Windscale and Three Mile Island caused health problems from iodine-131 in populations in downwind regions. It is now widely accepted there will be more 'Chernobyls'. Reactors must be decommissioned.
Demolition can cost as much as building a reactor.
The radioactive remains must be stored and guarded for hundreds of years. Reprocessing Millions of litres of radioactive water pour daily into the sea from the world's two commercial plants at Sellafield in Britain and Cap la Hague in France. Krypton-85 and other gaseous wastes are released from these plants. At Sellafield 500 kilograms of plutonium and 40 other radionuclides, have been released into the Irish Sea. Fish caught in the local waters are radioactive.