Allow me to introduce you to the relatively unknown Santa Susanna Field Laboratory meltdown/explosion, due to extensive cover ups over decades:

https://en.wikipedia.org/wiki/Santa_Susana_Field_Laboratory

https://en.wikipedia.org/wiki/Sodium_Reactor_Experiment

Still not fully cleaned up.

The Hanford site is a WWII era nuclear weapons facility and is not at all comparable with nuclear reactors for power generation.

while the comment you're replying to didn't make a distinction, i'll make the distinction that that was a nuclear weapons production facility (run by the federal government). further, some of it was constructed during WWII for the manhattan project.

so... not great handling, true. strong evidence about how nuclear power plants will be operated in the future? no.

The NRC does not regulate defense nuclear facilities.