We need a fitting location to safely bury it in. Otherwise it can pollute the ground and water. In Germany for example we dont have such a location. That and the issue of cost, no one wanting to build it, no one wanting to insure it, no state wanting to offer the space and no energy company wanting this energy led to us making the correct decision in moving away from it
We don’t add that level of scrutiny to coal ash which there is much more of and equally dangerous forever. Nuclear is the the only power source expected to address 100% of problems at any point in the future before it can even start construction.