Is There a Can Opener?

Economics relies on assumptions, right? Economic theory says, assume this and assume that. And in my view, the nuclear discussion is where people in effect invoke the notion of a can opener as they're answered to lowering the capital cost of nuclear power. They claim that there's an invention around the corner that's going to do it. i've been hearing that nek costs should be going down for forty years, and yet all they do is keep going up.