A buddy of mine, came to our platoon, circa '79 from cleaning up Enewetak. He enjoyed his time there, maybe you crossed paths. His name escapes me, we called guys like him "shake and bakes" cuz they came from a leg unit as E-5's!
Say what you want about global warming but the sea level is rising.
It's a moot point though, it's not like they were going to haul all that stuff somewhere else and bury it. And the concrete will weather away long before 1/10th of a half-life of plutonium has passed.