"Few thousands"? Do you even realize that 95% of used nuclear fuel is being recycled back into nuclear fuel, and what is left is absolutely tiny amounts? And these tiny amounts lose 95% of their radiotoxicity after just 100 years? This is simple physics, but Greenpeace will never tell you that.
@kravietz guaranteeing that these containers and that building remain intact for the next few thousand years. Also, this is the solution that germany came up with:
https://www.ksta.de/image/6481462/2x1/940/470/afc996b52c7b1dd73a877e0a21042a6e/lv/14826c00cddd75ff-jpg.jpg
https://en.wikipedia.org/wiki/Asse_II_mine