Information on Radiation Levels from Nuclear Bombs

IGLOOGREENHOUSE

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Hi! I was wondering if any knowledgeable peoples on this forum could help me out with working out some details on a post-apocalyptic story I'm working on.
In the story, a nuclear bomb from the soviet union hits the city of San Francisco in 1962. My question is this: With the nuclear technology the soviets had at the time, how long would the radiation last in the city? Months? Years? Decades? I'm not specifically talking about the radiation cloud, which would move with the weather for a time, but the radiation on the city itself. Will the radiation stay embedded in the metals near the city? Will it be dangerous say, fifty years later?
Thanks,
Chris.
 

Snick

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It would depend on what sort of bomb it was. The Soviets, like the U.S., had both fusion and fission bombs. Fusion bombs are relatively clean, only the trigger would produce much fallout. The fission bombs varied; some were very dirty, and some were not. Deciding what kind of explosive it was would depend on the delivery system also. I don't remember whether the Soviets had submarine launched missiles then, but I believe that they did. I don't believe that they had long range bombers that could get to SF, but I am not sure. I believe that their missiles had a maximum range fo a couple or three thousand miles, so they wouldn't make it from Siberia. That me\ans that they would have used sub launched missiles (unless I am mistaken), and do to size and weight those probabl were fusion warheads, so they were relatively clean. That means that there would have been a small cloud of fallout that would have dissipated in the mountains, and there would be little residual radiation, certainly no radiation that would last fifty years.

Then there is the possibility that they would have used a dirty bomb or even a cobalt bomb. Cobalt bombs were designed to make an area uninhabitable forr decades; you can search for the details.
 

Trebor1415

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My general layman's understanding is that once the debris that was contaminated by the initial radioactive fallout is cleaned up the radiation would be at safe levels. In general, it's the dust and debris that is scattered on top of everything that is dangerous, not radiation "embedded" in the metal of structures, etc.

This does assume some cleanup is done. If not, that might be a different situation.

Here's some links that might help.

http://www.fas.org/nuke/intro/nuke/radiation.htm

http://www.atomicarchive.com/Effects/effects17.shtml

http://howto.wired.com/wiki/Survive_a_Nuclear_Blast

http://en.wikipedia.org/wiki/Nuclear_fallout

http://en.wikipedia.org/wiki/Radioactive_contamination

http://en.wikipedia.org/wiki/Nuclear_weapon
 

BigWords

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There are also other problems with explosions... Buildings at the time would have lots of toxic elements in them (asbestos, certain plastics, that kind of thing) which can cause cancers and respiratory diseases alongside the effects of the initial nuclear explosion. Not something I would want to try and figure out - working the facts out can get very complex very quickly.
 

KatieJ

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The test sites where nuclear bombs were detonated in the 60's are still contaminated. Cesium, for example has a 30 year half life, so after sixty years it would be about 1/4 as radioactive as it was when the bomb exploded. (But still untenable - I don't think the Bikini islanders can return to their island yet.) The metal would become radioactive (the technical term is activated). Also the rain would wash contamination underground through the storm drains, causing residual contamination.

You could go into the area but not live there, the annual dose rate would be too high.