There is no way we can sustain anything approaching our current "life style" without nuclear power.
Even if we build nuclear power plants according to Victorian-era industrial standards we will probably be better off then if we don't.
We may come to regard some slight nuclear pollution as a sign of "progress" in the same way that people of the 1800's looked at the smokestacks of their coal-fired industries as a sign of progress.
The survivors of the twenty-first century may be slightly irradiated, but any cultures that do not embrace nuclear power will be (in our own twisted visions) "primitive," or much more likely dead.
A best case scenario of a non-nuclear powered world is Ursula K. Le Guin's
"Always Coming Home."http://www.powells.com/cgi-bin/biblio?inkey=7-0520227352-0(There's a part in that book about an ethanol powered tank that always makes me laugh...)
Another best case scenario would be that the next intelligent life form to inherit this earth will not be so bloody-minded stupid as humans were.
The worst case scenarios are that humans become extinct and there is no intelligent life on earth.
God will not be kind to humanity if we somehow manage to kill off the social insects and fungi. In that case Saint Peter will hand us a card at the pearly gates that says:
Go directly to Hell. Do not pass GO. Do not collect two hundred dollars.
Woooooooof! Just like lighting a match to find a bad gas leak... and we will be falling naked for eternity through clouds of flame.