Feasibility of "Dr. Strangelove" style, *very* long duration nuke shelters?

Factual Questions
1

…Inspired by this thread, and I hope remisser doesn’t mind my stealing his thunder a bit…

Plus, of course, possible SPOILERS for the movie “Dr. Strangelove; or, how I learned to stop worrying and love the bomb”…

[spoiler]In said film, charming emigre Dr. Strangelove suggests the possibility of building very long-duration fallout shelters in “some of the nations deepest coal mines.” And by “very long,” we’re talking about 80+ years.

Power could be provided by nuclear reactors, greenhouses could provide plantlife, animals could be bred and sssslaughtered, etc.[/spoiler]

My question is; Could such a bunker really be built, if one had the means and resources?

Of course, obviously, designing and building one in a couple of weeks, as implied in the film, would probably be asking a little much. So lets stretch that deadline out to…5 years? Would that be fair enough?

So…anyone want to take this one on?

2

In many ways it is similar to the problem of building long-term space bases or bases on Mars, the moon, etc, which have been widely considered by various agencies, except that in space you have a ready power source in the sun.

Assuming a steady power source and enough space, it should be possible to grow fruit and vegetables, recycle bodily wastes as fertiliser, get oxygen from photosynthesis, etc. You might need a very large hole; I don’t know how big, but I suspect it would not be impossible to build such a space given enough time.

My main worries would be:

  1. a power source that would run reliably for 80 years. You would be able to take spare parts in with you, but not do any large-scale maintenance or dispose of waste nuclear fuel, etc.

  2. preventing contamination leaking in. This is probably not a major issue given enough concrete.

  3. disease in the bunker. In a closed environment, infection would spread fast, and you would be dependent on what medications you took down. This would also apply to plant life and any livestock.

  4. going mad and killing each other.

Doubtless other people can think of more problems and solutions.