sitting in a shelter
There are the old CD (civil defense/FEMA) designs posted on line if you want to go there. There are also plenty of books available on the subject. I particularly like the US government printing office book "The Effects of Nuclear Weapons". That book also comes with a nuclear effects circular slide rule, cool, it can calculate everything from blast pressures, and prompt radiation. You hit on a key point, how long can you keep your head down. The old US minute-man-missile system was built with the ability to do a time delayed attack. The keys get turned and maybe one of the three missiles goes on its way immediately, and the other two in that group, go three weeks later when the enemy thinks it is safe. Also to the point, the BBC (for a TV program) hired several people to build the British version of our FEMA expedient shelters and paid them to stay inside with the supplies their government said they should take. In only a couple of days all the paid survivors had all quit their shelter sitting jobs, the cramped, confined spaces, loss of privacy, and yes, even the smell of a primitive toilet., drove them all out. If you have ever spent a few hours in a closed concrete shelter, you know that simple things like humidity (from your exhaled breath) get oppressive, it builds and builds. During parts of the waiting time after an attack, you may not be able to bring in outside air, the humidity and eventually the lack of oxygen will make you want to run. Getting one of the key chain gadgets to give you an indication, and alarm might be cool. I have an array of dosimeters and chargers to go with my survey meters. My gear is old school stuff, but will give me an accurate indication of what is going on, you may not need to know actual numbers. Having taken nuclear physics in college, I knew what readings represented an immediate risk, but really enjoyed my first radiation safety class in industry. One fellow student tossed the survey meter when the meter started indicating a source was near, they ran. Ha, ha, how did they know which direction to run with one meter reading? The purpose of our drill was to find the small lost radiation source. It makes for a funny story, but the point is, we should all have some basic numbers in out heads, to know when to take shelter and when to run. Thanks for all those participating in this thread.