Currently it's stored in nuclear waste bin, in pools in a few hangar. There is plan to store the in a geological stable hole, that we known that it won't move for a long time.

> The Nuclear Safety Authority has confirmed that the rock has not moved for several million years.

https://en.wikipedia.org/wiki/Meuse/Haute_Marne_Underground_...

Also, I'm not in the field, i just like to inform myself before having an opinon. Too many times there is lies spread about nuclear facilities.

Some of it is recycled as Mox.

Most of it is stored underground (FAR underground) in special regions where we know that the geological makeup is highly stable