> There are no technical hurdles remaining with respect to nuclear waste disposal.

That is very inaccurate. There are still a million problems to solve. nuclear waste is extremely dangerous. Even "normal" trash has been proven dangerous and difficult to get rid of with landfills leaking dangerous materials into ground water.

Accumulating nuclear waste for millennia hopping that nothing goes wrong is far from a proven solution. People cannot trust a solution when all concerns for people safety are disregarded.

..and regulation. The same with supersonic.