We still don't know the full extent of the environmental impact of the Fukushima disaster. Can we afford more incidents of that nature? I'm not certain.
That's nice, but we do know that burning fossil fuels kills a huge number of people [0]. Moving away from fossil fuels will require some form of nuclear power. Much of Europe has successfully transitioned most of their power to nuclear [1], so it's not like the concept is some experimental sci-fi dream. From an environmental standpoint, nuclear is by far our cleanest option based on all the information we have.
cue the anti-nuclear power comments