Mainstream acceptance is like third or maybe fourth on the list of biggest roadblocks to nuclear power. The simple truth is that nuclear electricity is outrageously expensive relative not just to gas but to renewables. The plants represent huge investments, and waste storage remains a problem that has literally never been solved by the market (i.e. nuclear waste processing has always been a government subsidy in some form or another).
Nuclear needs to make sense on a balance sheet first before you'll see uptake from environmentalists like me. But it'll happen. Make it a cheap carbon-free energy source and I guarantee you we'll advocate for it. Right now it mostly looks like another boondoggle.
I work in environmental impact assessment and most of our major projects have substantial opposition, usually on environmental grounds. That is true of schemes that are usually seen favourable by environmentalists. But government's can and do ignore that opposition if they want something built.
Also, these kind of comment threads talk about "environmentalists" or even "ecologists" as a single homogeneous group. That is simply not true. Most people in rich countries care about the environment to some degree but differ hugely in what they prioritize. The environment is a big topic that is more complex than just yes/no questions.
Nuclear needs to make sense on a balance sheet first before you'll see uptake from environmentalists like me. But it'll happen. Make it a cheap carbon-free energy source and I guarantee you we'll advocate for it. Right now it mostly looks like another boondoggle.