The reason everyone went for geological disposal is that it is reversible - All suggestions that end up in a situation where we cant get the stuff back if we decide to are irresponsible because we might well have uses for it once it is cooled of.

Nuclear waste straight out of a reactor is nasty stuff. Nuclear waste 500 years later.. is barely "hot" at all and contain a bunch of quite rare metals. in addition to the obvious: platinum, palladium, and technetium.

Tc is an beta-emmiter, but it has a very long halflife, doesn't exist in nature and makes nifty alloys.

This is why I tend to find concerns about really long term viability of storage a bit absurd. If we are still around at all, someone will be digging it back up.
And in an "no fossil fuels" context, noone will care.

Dry cask storage will do. Uhm. It'll probably do for the full five hundred years. There are older concrete structures than that standing, and casks are manufactured to a very high standard.