Things that have long half-lives are not very dangerous, as in order to have a long half-life it must be emitting radiation at correspondingly lower levels.
For example, something with a half-life of 100,000 years is emitting 1/100,000 of the radiation that one with a half-life of a year is.
Essentially it is like having a well. If you attach a firehose to it you'll drain it overnight. If you attach a dripper to it, it'll take centuries to drain.
I think, when you buy a new solar panel, you should also pay the full cost to pull it apart and dispose of it as well.
That works to make the manufacturer price in that externality, but it also likely leads to lease arrangements instead of outright purchase.
https://www.scientificamerican.com/article/coal-ash-is-more-...
also we don't need to prevent 100% of the waste from leaking just enough to keep from rising the natural ambient background that would be in the environment naturally before we extracted it. Secondly we have the means disposing of in newer reactor designs that use waste from older reactors as fuel and their waste has a much lower half life (down from 100,000 to 500 years)
