Interesting fact: Finland just built one, for €1 billion.

How can that be, if it's so incredibly difficult that Germany has not managed to do this?

The simple fact is that it has virtually nothing to do with any "difficulty" of finding a repository site, the problems are purely political, same as the US:

"The Government Accountability Office stated that the closure was for political, not technical or safety reasons.[6]" -- https://en.wikipedia.org/wiki/Yucca_Mountain_nuclear_waste_r...

Some German state governments even made this explicit, stating that they would not allow a repository to be designated until the German nuclear exit was finalized in their official coalition agreements.

Another nice little trick was changing the language to require the "best possible" site, rather than a suitable one. Sounds innocuous, but anyone with a bit of experience in algorithms know that in theory, this actually makes the task impossible, because how can you definitively prove that there isn't an even better site that you haven't looked at yet?

In practice it has made the process of finding a site incredibly lengthy, difficult and expensive. It doesn't help that the BASE, the Germany federal agency for nuclear waste has been completely taken over by the Green Party, so there is no interest in actually finding a site, and they spend almost their entire budget every year on spreading anti-nuclear propaganda.

> if it's so incredibly difficult that Germany has not managed to do this?

The german government and institutions were (are?) full of pro gas (pro russian/russian tied) people who spend decades in the government before bouncing of to russia to work for petro companies. It's hard enough when you try, so imagine how hard it is if you don't even try

> Gerhard Schröder, who served as Chancellor of Germany from 1998 to 2005, has worked extensively for Russian state-owned energy companies since leaving office.

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.