There is strong opposition to erecting any nuclear power stations,partly because they themselves may be dangerous,partly because of radioactive waste,but mainly because they produce materials which could be used in nuclear weapons,perhaps by terrorists.It is nuclear war,which could exterminate mankind,which is the great danger.It can be argued that most countries could build nuclear bombs whether or not the nuclear power industry expands,and that mankind might as well derive the maximum benefit from this source of energy,remembering that if it works as planned it causes far less pollution than does the use of foil fussels.

However,the larger the number of power stations,the greater the risk of an accident,with the release of a dangerous amount of radiation.It seems likely that with an enormous number of these installations in all countries,it will be difficult to ensure that all observe the type of precaution at present in force in the few existing stations,particularly with regard to the disposal of radioactive waste.Thus although nuclear power has,so far,done little harm,in the long run it might well be the most dangerous form of man-made pollution.

I briefly worked at the site of a decommissioned power station, and the level of security and the amount of rules they have are so high even on the site of an inactive station.
Also, did you know, that staff who work in the airline industry are exposed to more radiation than staff at a power station usually are on a day-to-day basis.
The vast majority of nuclear waste produced by nuclear power stations is what's classed as Low Level Waste, and that gives off less radiation than a cup of coffee!
But I would say that the main concerns regarding nuclear power stations, is the long decommissioning time they require, the amount of money they cost to run, and these days, the threat of "terrorists" crashing planes into them. But that last point is a whole new subject, since I believe that the real "terrosists" are the people who lie behind the scenes controlling the US and UK Governments.