Oh, Germany did - see for example the Asse II mine.

It just turned out that they weren't careful enough, so now they have got a giant nuclear waste storage pit which is unstable, is trying to leak into the groundwater, needs constant babysitting to prevent it from getting even worse, and will eventually need a nearly-impossible multi-billion-euro cleanup effort. At which point they'll be left with the original waste, plus a large amount of contaminated salt mine material, sitting above ground right where it started.

I reckon they would rather not want a repeat of this.

1. Asse does not house spent reactor fuel

2. It was an old mine turned into a research mine. It was never intended for actual use.

3. The waste there is mostly medical and low-level other waste like gloves.

4. It is actually safe where it is, moving it is another giant waste of time and money whose sole intent is to stoke fear and create costs.

Why the hell did they build this in a former salt mine with known water intrusion.