Reactor accidents will happen with enough reactors. And Chernobyl and Fukushima show that the consequences can be quite severe. Fukushima had "luck" that there was a lot of water involved, which is a decent radiation absorber. We also know that radiation doesn't disperse homogenously, so it could just enrich the food chain at specific points, probably without us noticing.

And there have been incidents on nuclear subs as well.

This is not against using nuclear power, but you should not downplay the risks. Because if something happens, the consequences can be devastating. There is also the problem with nuclear waste, which isn't really solved either.