Given the known, destructive effects of radioactive debris fallout that both the American and the Soviet governments had extensively studied secretly on remote, test ranges scattered on the planet, each society was in urgent need of building adequate, protective, “safety zones” to ensure some acceptable level of basic survival for the local population. Many would die, but a fortunate few could be saved for weeks or even months while living packed together tightly, underground 30 to 50 feet below ground level. Air and water filtration systems plus pumping stations would be required to mantain adequate supplies. throughout a faclity. Warehouses of refrigerated foods plus crritcal medications would also requrie the constant presence of skilled personnel to ensure a fair distribution of these essential items. Each facilty would also need to be energy independent through a system of nuclear or sun-powered stations.
Actual Systems in the USA
Amid nuclear war fears, here’s a look inside old NYC fallout shelters
Back during the Cold War, when the U.S. and the Soviet Union were in a superpower battle for influence around the globe, the threat of nuclear war was a given that many around the world lived with.
In response, fallout shelters were built across the United States.
Placed in apartment buildings, offices or schools by the federal Office of Civil Defense, these were the places where Americas were to go to take temporary shelter in case of a nuclear attack.
There were 10,000 such fallout shelters in New York City, and at least 200 on Staten Island, the Advance reported.
New York City was not unique
Nuclear Fallout Shelters Were Never Going to Work
https://www.history.com/news/nuclear-fallout-shelters-were-never-going-to-work
About the Seattle nuclear fallout shelter under I-5, the only one in the US