what is needed for a nuclear fallout shelter

Even around 8 kilometers (5 miles) you will suffer third degree thermal-burns still at 32 kilometers (20 miles) the heat can burn the skin off your body. If there is no shelter of this kind, dig as fast as possible.

If you can't find shelter, seek a depressed area nearby and lay face down, exposing as little skin as possible.

However, the actual damage radius is highly variable depending on the size of the bomb, the altitude of the explosion, and even the weather conditions at the time of the blast. 167, gives a distance of 13 miles on a clear day and 53 miles on a clear night for a one-megaton weapon. On a clear day, this can cause temporary blindness at very large distances.

Under no circumstances should you look directly at the fireball. If you are a few miles out, you will have about 10-15 seconds until the heat wave hits you, and maybe 20-30 seconds until the shock wave does. If within the vicinity of the blast (or ground zero), your chances of survival are virtually nonexistent unless you are in a shelter that provides a very (VERY) good blast protection. The bright light from a detonation of a nuclear weapon can be seen tens of miles away from ground zero. Aside from the geopolitical warning signs, your first warnings of an imminent nuclear attack will most likely be an alarm or warning signal if not, it will be the blast itself. The bulk of the US and Russian strategic arsenal are these types of bombs. Fusion weapons are also known as thermonuclear weapons since high temperatures are required to fuse deuterium and tritium such weapons are usually many hundreds of times more powerful than the bombs that destroyed Nagasaki and Hiroshima. Fusion (H-Bombs), using the incredible heat of a fission bomb 'spark plug', compress and heat deuterium and tritium (isotopes of hydrogen) which fuse, releasing immense amounts of energy.This is the most likely type of bomb to be used by terrorists. Fission bombs are the only type of nuclear bomb used in war so far. The daughter neutrons cause an extremely fast nuclear chain reaction. This bomb's power comes from splitting heavy nuclei (plutonium and uranium) with neutrons as the uranium or plutonium split each atom releases great amounts of energy - and more neutrons. Fission (A-Bombs) are the most basic nuclear weapon and are incorporated into the other weapon classes.

Learn about the different types of nuclear weapons.:

What is needed for a nuclear fallout shelter