I agree with the parent. The adage that one man's trash is another man's treasure is no where as true as with "Nuclear waste". The rarity of the elements contained in that waste and their unique characteristics means that it is likely we will find important uses for them. So it may make more sense to store them in a way that allows us to get back at them. Even if we don't find uses for them, we will surely develop better processes and technologies to extract and render them less dangerous.
Unless, of course, you subscribe to the pessimistic view that we are inevitably going to see the collapse of civilization and the return of illiterate barbarism. In which case, I would suggest that you are focusing on one of the smaller risks in that post-apocalyptic world.
My suggestion would be to find a way to safely store them for 50 years. If, at the end of that time, we still haven't found a better use for the "waste", then we repackage it for the next 50 years using the superior knowledge and technology that will then be available.