I don't think you can view the lack of a breakthrough as proof that research is lacking--I have no idea how govt or private funding of nuclear research compares to past funding, but it certainly exists. Even if the US weren't to embrace it, I think the incentive still exists in the supposition that the Chinese will try anything, and there's money to be made off of that. (You could say similar things about "clean coal" research too) Also, while there haven't been any new nuclear plants in the US for some time there have been advancements in extending the life of current plants and several successful uprating projects. There's also been the notable failure of SONGS out in California.
The US has numerous rules effectively forbidding things like fuel reprocessing and the construction of test reactors. Compared to the alternative energy areas, nuclear receives negligible research support--and much of what it does get is dedicated to fusion. In our current setup, it would be nigh impossible to ever have a breakthrough, at least in the US.
