The wonders of Science! make nearly anything possible.
Are we assuming that the vault denizens have gone inside because there was a nuclear war? In that case, no pumping in outside water (radioactivity), and no pumping in outside air.
I highly doubt that even now we could build air and water recycling systems which would be able to recycle the same air and water supplies for 200 years (water lost to evaporation, spillage, and so on being a serious issue).
I think it would be possible, but not easy. We have submarines in the U.S. that can stay under for a up to a year at a time, and that’s what they advertise, so I have to wonder what the REAL (classified) time frame is. And that’s a large tin can with at least 50 people, some with 200 people. If we had a chance to actually build a vault, I think we could do much better, especially if we combined earthship, off-the-grid, and military technology. With advances in Geothermal power, we might even be able to bypass nuclear power.
Yes, but that large tin can has an abundant supply of water*, and a year’s supply of food on board. The difference between storing (and/or growing) 200 years’ worth of food and one year’s worth of food is not trivial.
Of course, that’s not even taking into account the fact that even the most reliable nuclear submarine requires constant maintenance and refits in practice. That one-year-submerged idea is theoretical, rather than actually realistic, isn’t it?
*It occurs to me that I have no idea how a sub’s water supply works. Do they have small desalinization plants or board, or do they have to recycle fresh water?
A distillation type desalination plant. Probably a reverse osmosis backup unit as well. Both small… Showers are rationed. Waste water isn’t recycled.
Oh, and its really not all that hard to get radioactivity out of air and water, since the air and water itself aren’t radioactive, its the particles suspended in it. So filter the air real well, filters and ion exchangers on the water, and you can breath and drink from outside.
Subs get their water from desalination and reverse osmosis, yes. Yes, they also have a lot of food in storage. That’s why I said they would have to combine earthship technology with the current military technology. About the one year being theoretical, not according to my father. He says that subs have rarely tested the limits, but they have done so. He himself stayed under in a sub for 4.5 months. Older subs used to have to surface to do air exchanges, but I don’t know whether that’s still required. Either way, if one had earthship technology in there, you’d have plants to recycle/use the waste water and scrub the air. A sub is, of course, not a perfect vault, but I was thinking that with the varied technologies we have already, combining these technologies could produce the ability to create a functioning vault.
Would these filters be reusable, or have to be replaced regularly? I’m thinking if the latter is the case, you’d need entire warehouses full of the things to last 200 years.
Not really, assuming you’ve got some space - and the space issue is much less marked in a limitless budget underground vault than in a fast attack submarine :).
If you’ve got some dank underground space, dirt and a modicum of water, you’ve got yourself a mushroom growing operation. These things grow like… well, mushrooms.Human waste can be used as fertilizer in a pinch, but even with bare dirt you can get some fungi to grow nicely.
Of course, after about three months of eating mushroom salad with roasted mushroom and mushroom ice cream every single day, you’ve got a riot on your hands, but that’s another problem 
Eh, you just round up the troublemakers, isolate them, and next day you have a big ol’ barbecue featuring pulled pork. Or you call it pork, anyway. 
If you’ve got limitless budgets, then install sunlamps, keep a supply of lightbulbs and nitrates, and grow real food, either hydroponically or otherwise. There’ve been several ideas for colonization of moons or planets that have gone over this stuff in detail. I just think that if the government pooled all the information and technology we have on the subject, we could get a 200 year vault going. We have hydroponics, dwarfed plants, knowledge of animal husbandry, water scrubbing, air scrubbing, composting and biological waste management, varying power-producing capabilities and strategies, social contract experiments and results, nutrition requirement information, vacuum-sealing and other long-term storage options, recycling techniques, resumption of older creation techniques (clothing, textiles, etc.), and chemistry/other sciences. With all that, and significant storage for parts, components, chemicals, and even food, we could probably manage it. Not easily, and not necessarily comfortably for everyone, but I think we could manage above-subsistence-level survival for a large community. (By large, I’m estimating a village of 300-600 with diverse genetics upon closing the vault.)
Long pulled pork.
There’s a huge difference between storing a whole bunch of MREs and actually producing your own food. The submarine analogy really falls flat.
I beg to differ.
IMO. if you dont give a shit about efficiency, you dont need to do much of anything at all besides pile all the crap together right.
Depends on who you ask. Some of the people behind the Biosphere II experiments were quite frank from the beginning that they did NOT expect it to work perfectly. One of the major goals of the program was to find out what we didn’t know and what doesn’t work. Hence “experiment” not “foregone conclusion”. Apparently some results were a surprise. Whether or not anything useful came out of it is a different question, but no true research has 100% guarantee on results.
How about deep underground sources that are not exposed to surface contamination?
How about sperm on ice? If tech is reliable you can store a LOT of genetic variety in frozen sperm (or ova, although my understanding is that sperm freeze better, but what the hell, what have you got to loose as long as you have freezer space?). So, assuming tight population controls (and you have to have those) each couple has one children from their genes and one from the sperm bank/freezer. The frozen stuff won’t last forever but it will greatly increase genetic variety for a considerable time.
As for water.
There are plenty of places in the world where when you are pumping water from the ground, its water that has been (or has taken) hundreds if not thousands of years being at or getting at where it currently is. So, your ground water supply is good for hundreds if not thousands of years before it becomes radioactive, and even then its going have been significantly filtered by mother nature. You just pump the stuff, non of this pain in the arse recycling. Not that thats particularly hard either.
Has anyone calculated what the volume is for 200 man years worth of MREs?
Well, I found a commercial supplier herewhich quotes 48 12-MRE cases at 49"x42"x49" (including palette). MREs are 1200 calories, so assuming 2 per day, you’d need 60 cases for a year, which is 1.25 cases. So, 200 years is 250 cases, say 10x5x5, which would be 35’x21’x21’ per person.
Mind you, they only say the MREs will last 10ish years, so…
Thats a fair volume, but not an absurd amount (and MRE are fairly “poofy” anyway). Non-poofy stored food would have about half that volume.
Could you grow enough food to sustain one person in that volume?
Well, a nuclear submarine is completely self contained, has a crew of several hundred and can stay underwater probably for months with food being the limiting factor. A Vault is simpler because it doesn’t have to bear the stresses of an undersea environment or combat nor does it have to be as confined. So you could conceivably have “Raiders of the Lost Arc” size store rooms with nothing but replacement parts and long lasting freeze-dried MRE type meals.
Hmmmm…perhaps the most efficient way would be to only allow young, fertile, and very healthy women to populate the vaults, and allow each one to become pregnant two or three times, using a different sperm sample each time. This would maximize genetic diversity, but it would throw the social aspects all to hell.
I don’t think that I’d like to live in a society of all one sex, or mostly one sex, though. Even if I was lesbian or bi, I don’t think I’d like it.