|Postcard from - Repository|
Nuclear energy, as we currently engineer it is hardly perfect. Setting aside issues of risk and safe transort of materials, there's the problem of the waste product. Some things aren't too hard to deal with - clothing, dressings and the like can be burried in a shallow trench for a short time and they become safe to handle.
The real problem is in the waste from refurbishing fuel rods, materials from dismantled reactors and handling equipment. All of it highly radioactive, and likely to remain so for years, centuries or longer in some cases. So, what do you do with it?
It seems clear that burying it is the best solution, but where? A nuclear waste repository has to be geologically stable, not close to the sea and above ground water supplies. Interestingly, even politicians who favour nuclear energy don't seem to want a repository in their back yard, regardless of how suitable the area may be.
But there's another thing. Even if our current society collapses, there need to be markers that clearly say "don't dig here". The markers have to be obvious without relying on language, and they have to last for a thousand years or more.
It's an interesting problem, and there's a lot of research being done to come up with an answer.