One of the worst consequences of TMI was that nuclear plant construction virtually stopped. I haven't kept up with new developments since I retired several years ago, but even then the thing with nuclear power was PLEX - plant life extension; nuclear plants were licensed for thirty years of operation, and many of ours are well past that now. Tests and analysis showed continued operation to be safe, and the plants have been maintained, updated, and allowed to continue operation. However, you have to realize that we have much better monitoring and control technology, and newer plants would probably be a better way to go, but public perception (misguided by the press and anti-nuclear groups) has pretty well halted what could be a better path. The media I hold in complete contempt, some naysayers are just as guilty, but many are simply mislead.
We could certainly do better with spent fuel. Jimmy Carter ended hopes of reprocessing, and long term permanent storage sites have been stymied. The spent fuel storage at Fukushima was a travesty. Storage in those buildings should never have been allowed - simply not enough protection, and completely unable to deal with the hydrogen gas buildup and explosion once the stored fuel was damaged.