nuclear bunker

Factual Questions
1

let’s say i have an underground bunker. fully stocked. whatever the normal size is.

then a nuclear war happens.

how long can one feasibly live in an underground bunker? what would happen to the body after some months constantly in the bunker? when is it safe to come out?

2

I’m no expert by any means, and there are a lot of variables that will affect the answer, such as:

  • how big is your shelter? Household shelters were often quite small, while some of the government ones were thousands of square feet. The size of the shelter will affect how much you can exercise (which will influence your condition) and how much food you can store (which will influence how many calories you can afford to burn).
  • was the nuke a ground burst (which creates lots of nasty fallout) or an airburst (relatively clean - lots of blast effect but less fallout)? Also, how big was the bomb, and did it have any “enhanced” features (I dimly recall that you can use a cobalt casing to produce some extra-dirty fallout)? The amount and type of fallout determines how soon its safe to leave the shelter.
  • do you have a source of fresh water, or are you relying on canned/bottled water? Similar questions about your oxygen supply - are you using filters and filtering outside air? How many filters do you have?

I believe that most of the emergency shelters from the Cold War Civil Defence program were designed to provide shelter and minimum subsistence rations for about 2 weeks. People were expected to sit around calmly, expending minimal energy, until it was safe to leave. Everything was predicated on being able to leave in a relatively short time; e.g. empty water buckets were used for sanitation.

It was assumed that after 2 weeks, the radiation levels would have dropped sufficiently that you could leave the shelter and locate help, fresh supplies, etc. The kind of shelter seen in movies like “Blast From The Past” and RPGs like “Fallout” that could stay sealed for 20-30 years were a fantasy.