How does it effect you?

Nuclear radiation is the major effect unique to nuclear weapons. The other effects differ from conventional weapons only in degree. However it is fallout from nuclear weapons that poses special problems. When detonations occur on or near the Earth's surface, the radioactive substances produced are incor porated into the materials scoured from the crater. Much of this material is carried high into the atmosphere by the rising fireball. The subsequent fall of particles of earth and other matter is termed fallout. The threat of fallout was demonstrated dramatically in 1954 when fallout from a test explosion more than a hundred miles away caused injuries among the crew of a Japanese fishing boat and among the natives on Rongelap Atoll.

Each megaton of fission yield produces about 100 pounds of fission products. Thus, a 5-megaton surface burst of 50 percent fission and 50 percent fusion will produce about 250 pounds of fission products. At one minute after fission each ounce of these products is emitting gamma rays comparable to those from 15,000 tons of radium. In addition an explosion of any kind, occurring near

the surface of the Earth, causes material to be thrown up or drawn into the chimney of hot rising gases. A 5-megaton surface burst carries aloft about two million tons of soil and other surface materials in the stem and mushroom cloud of detonation. Therefore the material that ultimately returns to Earth as fallout is almost entirely soil. The radioactive residues incorporated into this soil are actually trace elements in a concentration of less than one-tenth part per million.

Soil drawn into the very hot fireball is vaporized. As the rising fireball cools material entering later is only melted. As the fireball cools further and forms the mushroom cloud, some material reaching the cloud level is virtually unchanged. As the fireball cools below the boiling point of the vaporized soil material, it begins to condense into liquid droplets, which eventually solidify into grasslike particles.

Because particles are tiny, the size of fallout particles is generally measured in microns, which is a length equal to one millionth of a meter. To put these sizes into perspective, consider that 1000 microns-1 millimeter- is about the thickness of a dime. A human hair 100 microns thick can be seen with the naked eye, but a spherical particle of the same size is difficult to see without a microscope.

In order to survive the hazards of radiation you must seek shelter. You must protect yourself against the most dangerous form of residual radiation- penetrating external radiation. Time, distances, and shielding are the three best means of protection from external radiation. If you can control the length of time exposure and the distance between yourself and the source of radiation, and if you place some absorbing or shielding material between yourself and the source of radiation, you can reduce the level of radiation significantly and thereby increase your chances of survival.

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The above animation shows a hypothetical nuclear attack on the continental United States. On the first frame, each circle represents a 20-meagton surface explosion of which ther are fifty. Each square represents a 10-megaton surface burst. These total 100. There are 100 triangles representing a 5-megaton burst. In this hypothetical attack, 250 weapons are dropped on 144 different targets which include militray, industrial, and populated objectives. The total yield of these 250 weapons is equivalent to 2500 megatons or 2.5 billion tons of TNT. The following frames show the effect of the fallout and the areas that would be affected after one hour, six hours, 24 hours, one week, and two months of initial imapact.

 

 

A high-range civil defense radiation meter (click for a closer look)