In 2068 WW3 happens, and most of the United States, Russia, Asia, Europe, and the Middle East is destroyed. But before the war, a company builds a group of shelters designed to protect 500,000 people in the United States, who could later rebuild civilization. My question is how realistic are these plans?


There are about 200 shelters, each that at maximum capacity can fit 10,000 people, but have a starting population of 5,000. These shelters are buried 10 feet underground and their outer walls are made out of blast-proof concrete. The shelters are Massive and expand down many levels down. They are all powered by a thorium reactor in the center of the shelter, which is maintained by a group of androids and a few humans.

Next to the reactor is a water purification station. There are five of these across the shelter. They take in human and animal urine, purify it, and send it through pipes for people to drink it.

To feed the shelter, there is a large farm that utilized fish farming to work. This provides the inhabitants with some fish and food. The plants grown there include sweet potatoes, tomatoes, potatoes, zucchini, oranges, etc. to provide them with a balanced diet. There is also some livestock such as chickens, pigs, and goats. No cows though as they don’t have enough space for them. They use the chickens for eggs and the goats for meat and milk. There are 20 large cafeterias each big enough to house 500 people to eat.

Each room can fit up to ten people. There are 4 beds and one television set in each room. The inhabitants don’t have there own washroom though and have to share 30 bathrooms. Each toilet has a bidet, so they don't have to store all that toilet paper. The showers are very water efficient, and inhabitants only have 5 minutes to shower to save water.

There is a large hospital that has some of the most advanced medical technology available. They can clone vital organs, have a biogel that can heal many wounds, and doctors are trained using virtual reality. There are also robotic surgeons that can perform on patients when doctors can’t. They also have genetic engineering, which is used on children before birth to rid them of any possible diseases the might have, as well as making them stronger and smarter.

At the age of 4, children go to school, where they can learn skills necessary to get a desired job in the future. Formal schooling ends at 18 (there is no college).

The shelter has many training facilities for people who want to become soldiers. It has weapons like laser rifles, gauntling lasers, machine lasers, etc. Each armory can equip 500 people with weapons, though more weapons could later be 3-D printed. The training facilities simulate real-life situations that they could face in the outside world.

Each shelter also offers recreational facilities, such as two swimming pools, two gyms, and a library. Inhabitants can also download movies to entertain themselves in their living quarters. The library does not contain physical copies of books but rather digitally stored copies.

Each shelter also has a seed storage facility, which freezes seeds so that they can be grown later when the inhabitants leave their shelter (think global seed vault but smaller).

The air filtration system can block out radioactive, chemical, or biological materials, keeping the people inside safe.

They plan to stay in the shelters for about 40 years until the world above is safe enough to live in.

Additional information about the world

  • This world is an alternate reality, where instead of falling, the Soviet Union prospered all the way until the 2060s.
  • The technology is very advanced, as there are 3-D printers that can make virtually any substance.
  • Nuclear power has nearly completely replaced fossil fuels.
  • Super advanced A.I. is available to average consumers.
  • And there are even extraterrestrial colonies in places like the Moon, Mars, and Venus.
  • Weapons technology is also very advanced, as they have lasers guns, invisibility cloaks, energy grenade, etc.

The United States government knew that nuclear war was on the horizon. So they gave the company 1 trillion dollars (which in this world is worth 2 trillion dollars) in order to build the shelters. When the war happened, politicians, high ranking military officials, executives of large companies, and their families evacuated into outer space.

So with all this in mind, is my idea for the shelters realistic?

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    $\begingroup$ These shelters are buried 5 feet underground That's it, this makes it sound like the "blast proof concrete" is < 5 feet thick. Also fit 10,000 people ... about 75,000 square feet that's 7.5 ft^2 per person at full capacity. Now my house is about 2000 ft^2 with 5 occupants, which is 400 each and it feels pretty cramped at times. $\endgroup$ Feb 4, 2018 at 6:06
  • $\begingroup$ I edited my question. Also at first there were only 5,000 people $\endgroup$
    – Bryan
    Feb 4, 2018 at 6:17
  • $\begingroup$ I changed it to 200,000 square feet $\endgroup$
    – Bryan
    Feb 4, 2018 at 6:23
  • $\begingroup$ I thought I saw a price tag in there? Price is pretty relative, as it's an Alt world. $1 USD could be worth $0.01 in your ALT reality. So you can say whatever arbitrarily large number you like. $\endgroup$ Feb 4, 2018 at 6:27
  • 1
    $\begingroup$ Bethesda called, they want Fallout back. $\endgroup$ Feb 6, 2018 at 19:16

4 Answers 4


As I mentioned in the comments.

I don't think they are deep enough:

These shelters are buried 5 feet underground

Nor are they large enough ( not by a few orders of magnitude )

fit 10,000 people ... about 75,000 square feet

This is about 7.5ft^2 per person, to put that into context a room that is 10ftx10ft is 100 sq feet. So that is like a room that is 2ft by 2.5ft. And they have to live here for years?

Your probably going to need at least 2000 sq ft, or more per person. Because not all the space is living space. Some is hydro phonics, some is schools, power generation etc. Even if we cut that in half, that is still several orders of magnitude more then what you have.

A standard family of 4 in the US can do pretty good in a house that is around 1500-2000 sq feet. And consider, they don't spend every minute in their house. Sure there is some space that could be shared with the community, such as kitchens bathrooms etc. but given how much time they have to spend together they will be living on top of one another and that is a recipe for a lot of conflict.

People need space and a sense of privacy, or there will be a lot of conflict. Even with the lower number of 5000 people, we have about 15 sq ft each, which is about the size of a large bedroom.

You will need something like 12 sq ft, just for a bed, 2ft x 6ft, of course you could stack bunks and sleep in shifts, but would this work for 20 years, how about 40. So you will probably need about 250-500 sq ft, per person as a baseline minimum. at 400 sq ft, that is a room only 20ft by 20ft. So for 5000 people, that would be 2 million sq feet. You could easily double this, you could also get away with much less, but it depends on how long they are cupped up.

Generally the longer they have to spend confined, the more space you will want. This gives them some room for recreation etc.

My guess is for 5000 you would need at least 3 million sq feet, for that length of time. You could get away with a million but that's not going to leave much personal space once you factor in utility systems etc.


This is why I said you were off by orders of magnitude, which means your not even in the ballpark range.

Now I am not an engineer so I don't have some formula for this, but just ask yourself could you survive for 40 years with personal space that amounts to less then a 10ft by 10ft cube ( this would be 100 sq ft per person for 500,000 sq ft) and like I said, once you add in power plants, food, recreation area, utility areas etc will all cut into that space.

So In summery (just some general ideas):

  • I would say that the bare minimum would be 350,000 square feet, at this size you will probably have bunk rooms that have 3 bunks stacked. You may get away with 2, if you share bunks with shifts. 70ft^2/person

  • I would say with 500k you will still have, bunks 2 high, or have to share bunks in shifts 100ft^2/person

  • At 1 million you may have single bunks and not have to share, maybe single rooms 200ft^2/person

  • At 2 million, you may be able to have a small room/appartment for each person/family unit 400ft^2/person

  • At 3 million + You would have a small apartment with your own bathroom, kitchen etc. 600ft^2/person

Some of this depends how much room your power systems and other non-living space (like 20 cafeterias) are as these will all eat into personal living space.

The big issue is the amount of time, if they were saying for a few months having common bunk areas would be ok, it's better then being irradiated after all. But once you exceed a few years, people are going to need their own personal space. Even having them in rooms with bunks, after 40 years is going to be much like serving a life sentence in prison. That's ok if all you want to do is survive, but in such a tight high stress environment I can see fights and revolts breaking out.

If it was me, I would leave it vague. It's nice to have these numbers when figuring out the scale, but you can paint yourself into a corner by setting concrete values. You can just say it's a massive complex that spans several levels.

I would also have apartments, which would allow them to keep a family structure.

Have a level for sleeping, personal space, rec space. A level for food and production. A level for Command an control functions and weapons storage, training facilities etc. etc..


I assume you need to make this work for your story, and explanations why it won't ever work are not helpful.

If you want to survive a near miss, go deep. Much deeper than 5 feet. I'm wondering, are you living in the US or elsewhere? Is it natural for you to think in feet?

Look at this: Effects of Nuclear Earth-Penetrator and Other Weapons chapter 2

If you do not expect the shockwaves from a direct hit, consider a depleted mine. Look at this salt mine. Volume or surface area are not the problem, all you have to do is to seal the exits and walls.

Things will wear out, and your recycling systems for things which are expected to wear out will not be 100% effective. To give some random thoughts:

  • How many toothbrushes do you have in storage? If every inhabitant is issued one per year, that would be roughly 400,000 of them. Go to a shop and look at a shelf with toothbrushes, try to estimate how many there are. Then estimate the volume to store them.
  • Those television sets for entertainment (and library access). How long do you expect them to last? Say they wear out after a decade of frequent use. You need roughly 4,000 spares. Go to a shop and look at the box for a TV set, or a computer monitor.
  • Say your recyclers get 99.99% of the daily water use back in usable form. That would mean you need roughly four times the water in circulation as reserve.

Of course that's assuming stuff will last that long in storage. If I took a modern TV, put it in an attic somewhere, and then decided to plug it in, I'l expect it to fail. The electronics age over time.

Those training facilities, people learn to shoot laser rifles with hundreds of yards range, right? In a dynamic, "tactical" scenario and not on a static firing range. Even a static range 500 yards long and 10 yards wide would be 45,000 square feet, and that wouldn't allow the simulation of fire-and-maneuver tactics by teams.

  • $\begingroup$ The training facility is not that big, it’s only 20 feet big $\endgroup$
    – Bryan
    Feb 4, 2018 at 13:58
  • $\begingroup$ @Bryan, what can be trained in 20 feet? Sure, you could simulate a target range with smaller and bigger images to simulate different distances, especially with lasers which are straight-line, lightspeed weapons, but the colonists won't learn to move. Standing shoulder to shoulder and shooting went out of fashion 150 years ago. What about room clearing? $\endgroup$
    – o.m.
    Feb 4, 2018 at 16:42
  • $\begingroup$ It’s 80 feet big $\endgroup$
    – Bryan
    Feb 4, 2018 at 17:59
  • $\begingroup$ And it has simulated house to train them on clearing rooms and shooting targets above them $\endgroup$
    – Bryan
    Feb 4, 2018 at 18:24
  • 1
    $\begingroup$ @Bryan, that might be enough to train for indoor fighting, but still not enough for outdoor fighting. Perhaps that could become a plot point -- if the bunker dwellers go outdoors, they will be pretty bewildered and "out of their depth." $\endgroup$
    – o.m.
    Feb 5, 2018 at 6:01

The scale of underground facilities you would require to house that many people plus common areas plus infrastructure plus livestock is truly astoundingly enormous.

Even under brutal factory-farm conditions, space for livestock is unrealistic. A more realistic expectation for food sources will rely primarily upon modified yeasts and algae, with some variety (mostly just a psychological comfort for a sense of eating "real" food). Aquaponic/aeroponic produce, mushrooms (mostly to aid in breaking down waste and as construction material, but doesn't take much additional resources for some edibles/medicinals too), and a variety of insects for protein - that is about as far as is reasonable, and even then those are supplements to enliven the bulk of the meal.

There simply isn't additional room for livestock much less the space to devote to growing their fodder. Even fish are extremely questionable (more efficient to grow people food rather than fish food, and the people alone will produce enough for the plants).

Shared accomodation is not advisable for anyting long-term. The psychological value of having your own space is immense, even if it is tiny. Something just large enough for a bed, negligible storage (not like people will have much "stuff"), and a sanitary area. You could split them to have essentially a capsule hotel style sleeping and sanitary stalls (toilet/shower stalls with access to clean onezies and a laundry shute), but this might get a little too claustrophobic. Allocating everyone a 2m by 3m personal sleeping/bathing space would probably be worth it just for psychological security.

You probably want to avoid talking about details like the length of a shower, but in any case restricting the length of showers is a bad idea - either your recycling system is robust enough it doesn't matter, or you're so near failure that such bathing practices as showering is too wasteful regardless (exfoliate with a rubbing cloth and wipe down with a sponge).

Traditional 19th century education concepts seem silly (already silly today, but exceptionally silly there). People will spend plenty of time in VR learning from personalized educational games and guided exploration programs following their interest at their leisure through all ages. There isn't much of a need for more than a small fraction of the population to actually do any work beyond cleaning, and even then the AI can guide them through most maintenance/repair tasks until they've enough on the job experience to know what to do themselves (much better than formal traditional schooling).

Probably best not to detail a thorium reactor specifically - you really don't want to get into such details as it won't add anything to the story while potentially causing unforeseen issues later - just refer to it as a reactor and leave it vague.

And a trillion may sound like a lot of money, but when it comes to building an array of underground cities, it isn't nearly enough.


Everyone else has mentioned scaling issues so I won't cover those.

I will instead cover two different issues:

Uranium Shortage:

There isn't enough fissionable Uranium around to switch completely to nuclear power. There is enough Uranium to run the shelters but not for the entire world to be converted. It would only last for about 10 years.

Heck, even without full conversion we are facing a shortage (article).

Various agencies have tried to estimate how long these primary resources will last, assuming a once-through cycle. The European Commission said in 2001 that at the current level of uranium consumption, known uranium resources would last 42 years. When added to military and secondary sources, the resources could be stretched to 72 years. Yet this rate of usage assumes that nuclear power continues to provide only a fraction of the world’s energy supply. If electric capacity were increased six-fold, then the 72-year supply would last just 12 years.

If they switch to thorium, the can last longer (Forbes article). Thorium is, arguably, a better fuel for reactors. The main problem is that it can't be used for making bombs. However, if your world has been in a cold war that long, maybe the military has, instead of hiding bomb making in the energy industry decided that uranium is too precious for running in reactors.

Soviet Economy:

What changes will you make to allow the Soviet economy to survive? Or, how did the Soviet Union react differently to their economic crash?

In our reality the US as a contributing factor in their economic collapse.

  1. Vietnam War: we spent a lot less there than they did.
  2. Afghanistan: We spent a lot less there than they did.
  3. SDI: We did a lot of research on how to disable a ballistic nuke. Our plans had a flaw, for about $100k per missile, they could make the missile immune to SDI. They modified their missiles. We built nothing but got a lot of research in that led to several modern devices. Reagan is probably still laughing about that.

So, either the Soviets reacted differently or we did.


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