This article tells about signal "Atom" and its intended effect on Moscow metro:

  • All trains stop, escalators automatically start move downwards.

  • After 15 min, all hermetic gates on metro entrances and in tunnels automatically start to close. They are impossible to stop or disable. The gates are really huge and weighing tens of tons.

  • In case people block the automatic doors, the police can fire on the blocking people.

  • Electric substations switch to autonomous generators

  • The air is starting to be cleaned. The gates between stations open when the air inside is clean.

  • Toilets, food and tools stores get automatically unlocked.

  • Groups of scouts-dosimetrists are formed, which start to make scouting excursions to the surface using special suits via airlocks with showers.

enter image description here

Airlock with shower

  • Exit to the surface is permitted only if air defense stopped any missiles reaching ground, otherwise the people are supposed to remain underground forever.

This list of anti-radiation measures seems to be really a huge overshoot.

The radiation from the bombings seems to be much less than that from any nuclear plant disaster and usually goes away in hours after bombings (at least for the purpose of walking outside). The effect on soil will be more protracted, but the soil can be replaced in normal restoration wokflow.

I do not see any reason for:

  • Huge, multi-ton hermetic gates enter image description here
  • Firing on people who slow down the gates closing
  • Keeping people underground for days

Anyway, any possible casualties from radiation seem to be tiny compared to the casualties from the bombings themselves.

Can anyone please clarify, whether I am right that this radiation-scare was (is) an overshoot?

  • 3
    Multiple megaton warheads hitting - not sure the metro would have been underground everywhere afterwards.
    – Jon Custer
    Mar 18, 2021 at 1:19
  • 1
    I think you've glossed over a few things. "The radiation from the bombings seems to be much less than that from any nuclear plant disaster and usually goes away in hours after bombings (at least for the purpose of walking outside)" Citation needed. "The effect on soil will be more protracted, but the soil can be replaced in normal restoration wokflow." Citation needed. Can we just "replace soil"? All of it? Where do we get it? How do we move it? Where does the irradiated soil go? This seems to be brushing over a colossal civil engineering project.
    – Schwern
    Mar 18, 2021 at 18:47
  • 3
    I cannot help wondering if perhaps there was some psychological component, at least in the more prominent ones (like at Moscow's metro): "Let the people see how thick the doors are so they believe that we can defend them".
    – SJuan76
    Mar 18, 2021 at 21:48
  • 1
    @Anixx 1 sq km of soil 7 cm deep is 100,000 tons or about 3,000 truckloads. I recall a scene in The Day After where a bunch of farmers are blithely told to just scrape off the top few inches of soil. They incredulously ask with what? How do they haul it away? Where do they get the fuel? Where do they put it? What do they replace it with?
    – Schwern
    Mar 19, 2021 at 21:12
  • 1
    @Schwern Scraping off a few inches of top-soil is not that difficult with a shovel and wheelbarrow. In the kind of apocalyptic scenario we are talking about, a bunch of human beings who can't roll up their sleeves and get something like that done, deserve their fate. It is comparable to the work done clearing new farm land using primitive tools even today. Mar 21, 2021 at 9:34

2 Answers 2


The main question I see is the issue concerning 'Keeping people underground for days'

The issue which these civil defense type shelters were looking at isn't just the immediate local contamination due the nearby blast. It is what we call fallout. Every particle in the region of an explosion is sucked into the blast area, and then projected upwards within the classic 'mushroom cloud' we see in so many pictures. These particles are radioactive, and they take time to come back to ground. A single line of the linked Wikipedia article has an estimate on this effect (emphasis mine):

Fallout radiation decays relatively quickly with time. Most areas become fairly safe for travel and decontamination after three to five weeks.

This is the reason the civil defense plans were accounting for an extended stay underground. We can track the source from the linked wiki to an article from 1957 on The Nature of Radioactive Fallout and its Effects on Man relating to estimates concerning radiation belts formed worldwide after the nuclear testing being done in the 50's:

The second type stropospheric fallout consists of that material injected into the atmosphere below the tropopause which is not coarse enough to fall out locally This debris is sufficiently fine that it travels great distances circling the earth in the general latitude of the explosion until removed from the atmosphere by rain fog contact with vegetation and other meteorological and or physical factors The average tropospheric fallout time is estimated as 20 to 30 days The fraction of the fallout which is in this category depends mainly on the size of the explosion and the conditions of firing If the explosion exceeds a certain minimum size about one megaton MT the fireball will have enough energy to penetrate the tropopause carrying fission products into the stratosphere Smaller detonations leave in the troposphere all debris not deposited locally The fraction of the fission products from a large weapon that remains in the tropopause depends on the size of the explosion conditions o firing and meteorological factors

Remember this circulation of radiation which would last 20-30 days is cumulative. Every bomb detonated would contribute to it. And it would continually fall out of the atmosphere to the ground below. This is the radiation hazard the designers of your civil defense system were building to accommodate. All the atmospheric radiation for every bomb detonated worldwide would be circulating for up to a month after the nuclear war they were trying to plan for.

This is the history of what the system was designed to handle. The question of did they overestimate, thankfully we don't know. Any guess there would be speculation.

  • 1
    Great last paragraph. I saw a statement that just a few dozen H-bombs would kill the birds, then we'd be overrun with bugs. Mar 18, 2021 at 14:20
  • 3
    And I’d prefer an overestimate to underestimate if I were down there.
    – Jon Custer
    Mar 18, 2021 at 14:42
  • 3
    Worst-Case Scenario is the operative phrase, in more ways than one...
    – justCal
    Mar 18, 2021 at 15:01
  • During the 1960s and 1970s, thousands of bombs were detonated. Nobody took people into shelters though.
    – Anixx
    Mar 19, 2021 at 3:02
  • Yes, of those thousands (2,121 total ), 520 were atmospheric. Not detonated all at once, not detonated in populated regions. I don't know the date associated with your question, but in 1980 for instance, the combined stockpile between the US/USSR was over 50,000 weapons.
    – justCal
    Mar 19, 2021 at 3:30

Yes, the effect of radiation was significantly over-estimated (it still is by most people). But it was still bad enough to ruin quite a few days.

The worst immediate effects of a nuclear bomb are the blast and heat damage. Immediate radiation is also quite dangerous for people close to ground zero who survive the blast and heat. Many such survivors will die of radiation poisoning in the next week or so.

As far as I know, none of this was significantly mis-estimated. (Hint: it was really bad for people within a mile or so of ground zero.) What did turn out to be overestimated was long-term effects of radiation such as cancers in later life for people who were nearby and survived the blast and its immediate effects or who were more distant.

As far the as the huge doors go, they would appear to be primarily aimed at preventing blast damage. Assuming they were well-engineered, they'd probably work pretty well.

Once the blast and its immediate effects are over, residual radiation declines rapidly -- it has to, because high radiation means a rapid rate of radioactive decays which means a short half-life.

But to be clear, what's left is still very dangerous! (If I were close to ground zero in an attack, my own preference would probably be to stay in the shelter for up to a week and then get out and try to get out of town.)

All in all, what you describe sounds like the sort of panicky over-reaction we saw in the US in the 50s and 60s, but with a bigger budget behind it.

  • "What did turn out to be overestimated was long-term effects of radiation" - my point is, radiation poisoning of the environment also, at least, for normal nuclear warfare (as opposed to intended radioactive or chemical pollution). And radiation pollution danger is much greater near nuclear plants that could be destroyed in the blast, not from the bombs themselves.
    – Anixx
    Mar 18, 2021 at 7:19
  • 1
    Long-term radiation effects were seriously over-estimated, but don't go too far in the opposite direction in compensation.
    – Mark Olson
    Mar 18, 2021 at 11:21
  • I am not talking about "long-term radiation effects" at all. To have long-term radiation effects, you need to have long-term radiation.
    – Anixx
    Mar 18, 2021 at 21:02

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