WIPP exists[0]. This is just for weapons waste (which is a much higher concern btw). But honestly storing waste material on site isn't that big of a deal. The DOE has also invented significantly better storage systems in the last 50 years but simulations and small scale testing do not count as proven enough for large scale testing ¯\_(ツ)_/¯

But there are other deep geological repositories around the world.[1]

[0] https://en.wikipedia.org/wiki/Waste_Isolation_Pilot_Plant

[1] https://en.wikipedia.org/wiki/Deep_geological_repository