Sentence:  He says the resurgence of nuclear energy around the world &mdash; even in <WSD>ultragreen</WSD> countries like Finland &mdash; reflects the simple fact that nuclear power has more potential to replace and reduce carbon emissions than anything else, and that, leaving out the Model T technology of Chernobyl, its worldwide safety record remains almost impeccable. 
Meaning of the word marked with <WSD> tags:  Taking a great deal of responsibility for the natural environment.