It was right after the Fukushima disaster which was a last straw. Press coverage of nuclear energy by then was mostly negative thanks to Greenpeace and their campaigns against disposal of nuclear waste, history of Chernobyl explosion was still fresh, so politically keeping nuclear afloat was a risk. And of course, when calculating the real costs (i.e. including long-term nuclear waste storage and monitoring) it appeared not so attractive option to keep it.