There is currently still no licensed long term storage site for high-level waste in the world. That is amazing really. I consider that a major issue, even if the barriers are mostly political rather than technical.
"Here's a nice loaf of bread. Let's bury it in a mountain!"
Utter madness.
https://en.wikipedia.org/wiki/Onkalo_spent_nuclear_fuel_repo...
https://www.science.org/content/article/finland-built-tomb-s...