in September 1961, under the direction of Steuart L. civilian alarm device was engineered and tested but the program was not viable and went defunct about 1966. The National Emergency Alarm Repeater (N.E.A.R.) program was developed in 1956 during the Cold War to supplement the existing siren warning systems and radio broadcasts in the event of a nuclear attack. These buildings were usually placarded with the yellow and black trefoil sign. Plans were made, however, to use existing buildings with sturdy below-ground-level basements as makeshift fallout shelters. Idealized American fallout shelter circa 1957.ĭuring the Cold War, many countries built fallout shelters for high-ranking government officials and crucial military facilities, such as Project Greek Island and Cheyenne Mountain in the United States and Canada's Emergency Government Headquarters.
6.2 Measures to lower the gamma dose rate.6 Other matters and simple improvements.5 Weapons versus nuclear accident fallout.4 Different types of radiation emitted by fallout.A fallout shelter is designed to allow its occupants to minimize exposure to harmful fallout until radioactivity has decayed to a safer level.Īlthough many shelters still exist, some even being used as museums, virtually all fallout shelters have been decommissioned since the fall of the Soviet Union in 1991. Much of this highly radioactive material then falls to earth, subjecting anything within the line of sight to radiation, a significant hazard. The fallout emits alpha and beta particles, as well as gamma rays. When this material condenses in the rain, it forms dust and light sandy materials that resembles ground pumice. Many such shelters were constructed as civil defense measures during the Cold War.ĭuring a nuclear explosion, matter vaporized in the resulting fireball is exposed to neutrons from the explosion, absorbs them, and becomes radioactive. A fallout shelter is an enclosed space specially designed to protect occupants from radioactive debris or fallout resulting from a nuclear explosion.
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