It's harder than you think, unfortunately. Nuclear weapons have a few kilograms of radioactive material, reactors have more than a few tons. The Yucca Mountain repository, the best that nuclear engineers could come up with, had to be certified to be safe for 10,000 years...but literally after 10,000 years things could have gotten out of control. It's a tough problem.
That said, it means that we have to try harder. The problem is not going to go away; we have to pursue better approaches.