jeffquitney
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Radiological Defense 1961 Office of Civil Defense
🕑 Added 2020-11-05 21:20:42 +0000 UTCmore at http://quickfound.net/
On 'nuclear fallout and its potential for damage in the event of an attack on the United States.'
Originally a public domain film from the Library of Congress Prelinger Archives, slightly cropped to remove uneven edges, with the aspect ratio corrected, and one-pass brightness-contrast-color correction & mild video noise reduction applied.
The soundtrack was also processed with volume normalization, noise reduction, clipping reduction, and/or equalization (the resulting sound, though not perfect, is far less noisy than the original).
https://en.wikipedia.org/wiki/Nuclear_fallout
Wikipedia license: http://creativecommons.org/licenses/by-sa/3.0/
Nuclear fallout, or fallout, is the residual radioactive material propelled into the upper atmosphere following a nuclear blast, so called because it "falls out" of the sky after the explosion and the shock wave have passed. It commonly refers to the radioactive dust and ash created when a nuclear weapon explodes. The amount and spread of fallout is a product of the size of the weapon and the altitude at which it is detonated. Fallout may get entrained with the products of a pyrocumulus cloud and fall as black rain (rain darkened by soot and other particulates, which fell within 30–40 minutes of the Atomic bombings of Hiroshima and Nagasaki). This radioactive dust, usually consisting of fission products mixed with bystanding atoms that are neutron-activated by exposure, is a form of radioactive contamination...
Fallout comes in two varieties. The first is a small amount of carcinogenic material with a long half-life. The second, depending on the height of detonation, is a huge quantity of radioactive dust and sand with a short half-life.
All nuclear explosions produce fission products, un-fissioned nuclear material, and weapon residues vaporized by the heat of the fireball. These materials are limited to the original mass of the device, but include radioisotopes with long lives. When the nuclear fireball does not reach the ground, this is the only fallout produced. Its amount can be estimated from the fission-fusion design and weight of the weapon. A modern W89 warhead weighs 324 pounds (147 kg). The fission bomb dropped on Hiroshima (Little Boy) weighed 9,700 pounds (4,400 kg)...
After the detonation of a weapon at or above the fallout-free altitude (an air burst), fission products, un-fissioned nuclear material, and weapon residues vaporized by the heat of the fireball condense into a suspension of particles 10 nm to 20 µm in diameter. This size of particulate matter, lifted to the stratosphere, may take months or years to settle, and may do so anywhere in the world. Its radioactive characteristics increase the statistical cancer risk. Elevated atmospheric radioactivity remains measurable after the widespread nuclear testing of the 1950s.
Radioactive fallout has occurred around the world, for example people have been exposed to Iodine-131 from atmospheric nuclear testing. Fallout accumulates on vegetation, including fruits and vegetables. Starting from 1951 people may have gotten exposure, depending on, whether they were outside, the weather forecast, and whether they drank contaminated milk, vegetables or fruit...
Examples of both intermediate and long term fallout occurred after the Chernobyl accident. Chernobyl was a nuclear power facility in the Soviet Union. In 1986 it accidentally contaminated over about 5 million acres in Ukraine. The main fuel of the reactor was uranium, and surrounding this was graphite, both of which were vaporized by the hydrogen explosion that destroyed the reactor and breached its containment. An estimated 31 people died within a few weeks after this happened, including two plant workers killed at the scene. Although residents were evacuated within 36 hours, people started to complain of vomiting, migraines and other major signs of radiation sickness. The officials of Ukraine had to close off an 18-mile area. Long term effects included at least 6000 cases of thyroid cancer, mainly among children. Fallout spread throughout Western Europe, with Northern Scandinavia receiving a heavy dose, contaminating reindeer herds in Lapland, and salad greens becoming almost unavailable in France.
Local fallout
During detonations of devices at ground level (surface burst), below the fallout-free altitude, or in shallow water, heat vaporizes large amounts of earth or water, which is drawn up into the radioactive cloud. This material becomes radioactive when it combines with fission products or other radiocontaminants, or when it is neutron-activated...
