I know a guy in his 90's that was a nuclear engineer, and he was saying that the solution is to dig a big "bowl" under the reactors, and fill it with lead and other metals and some kind of glass as you go along and they should have started this process within weeks, but were looking for the least expensive way to do it.
He then went on to say there is no reason that we can't have safe nuclear mini-reactors like bigger models of the kind used on subs & ships except for all the political BS. His team pushed for 38 years trying to get permits and it was pretty much impossible. He said the US could have been the #1 supplier of energy, without oil, coal or natural gas, and it would have been trillions of dollars cheaper than anything else.
He said they even had a brilliant way to dispose of the rods safely, but that is still classified.