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Simulations show how each of the cities would be affected by a kiloton blast — the kind detonated over Hiroshima. New York City would have the most fatalities. San Francisco would have the least. Visit Business Insider's homepage for more stories. Wellerstein's NukeMap tool lets you detonate a hypothetical nuclear bomb over any major city in the world. Human response to ionizing radiation is subject to great scientific uncertainty and intense controversy.
It seems likely that even small doses of radiation do some harm. Fallout radiation is received from particles that are made radioactive by the effects of the explosion, and subsequently distributed at varying distances from the site of the blast. While any nuclear explosion in the atmosphere produces some fallout, the fallout is far greater if the burst is on the surface, or at least low enough for the firebalI to touch the ground.
The significant hazards come from particles scooped up from the ground and irradiated by the nuclear explosion. The radioactive particles that rise only a short distance those in the "stem" of the familiar mushroom cloud will fall back to earth within a matter of minutes, landing close to the center of the explosion. Such particles are unlikely to cause many deaths, because they will fall in areas where most people have already been killed.
However, the radioactivity will complicate efforts at rescue or eventual reconstruction. The radioactive particles that rise higher will be carried some distance by the wind before returning to Earth, and hence the area and intensity of the fallout is strongly influenced by local weather conditions.
Much of the material is simply blown downwind in a long plume. Rainfall also can have a significant influence on the ways in which radiation from smaller weapons is deposited, since rain will carry contaminated particles to the ground. The areas receiving such contaminated rainfall would become "hot spots," with greater radiation intensity than their surroundings. Ground Zero The term "ground zero" refers to the point on the earth's surface immediately below or above the point of detonation.
Blast Effects Most damage comes from the explosive blast. Thermal Radiation Effects Approximately 35 percent of the energy from a nuclear explosion is an intense burst of thermal radiation, i. Plutonium is created when an atom of uranium absorbs a neutron and becomes plutonium The reactor generates the neutrons in a controlled chain reaction.
For graphite to succeed as a moderator it must be exceptionally pure; impurities will halt the chain reaction.
Heavy water looks and tastes like ordinary water but contains atoms of deuterium instead of atoms of hydrogen. For heavy water to succeed as a moderator, it too must be pure; it must be free of significant contamination by ordinary water, with which it is mixed in nature. To achieve this separation, a specially shielded chemical plant is needed to chop the fuel rods into pieces, dissolve the radioactive spent fuel in acid, and then extract the plutonium in pure form.
This isotope, like plutonium, is unstable and fissions when struck by a neutron. It is, however, found in natural uranium at a concentration of only 0. To be useful in a nuclear weapon, the concentration must be increased. This is accomplished by a process known as enrichment. Because the isotopes of uranium are identical chemically, the enrichment process exploits the slight difference in their masses. Uranium enriched to greater than twenty percent uranium is called highly enriched.
Nuclear weapons typically use a concentration of more than 90 percent uranium Thus, a separate chemical processing plant must be constructed to convert the uranium into gaseous form.
These typically require high-precision manufacturing, which can be accomplished only with specialized equipment or materials. Such components also require specialized testing equipment. Selected components and equipment are listed below.
The energy released by a nuclear explosion comes in several forms: pressure from the blast, thermal radiation, nuclear radiation, and an electromagnetic pulse. The damage inflicted by the various effects depends upon the size and type of the explosion. The detonation produces a drastic increase in atmospheric pressure and severe transient winds.
Due to the extreme temperature and pressure created, a massive shock wave is promulgated outward from the detonation point. A standard chemical high-explosive produces only 5, degrees centigrade 9, degrees Fahrenheit.
A one megaton explosion can produce third degree burns which destroy skin tissue at a distance of five miles. The extent to which burns are inflicted depends on weather conditions. The initial radiation consists of neutrons and gamma rays, which can travel great distances, penetrate considerable thicknesses of material, and inflict fatal damage on human tissue.
Initial radiation can be intense but has a limited range. For large nuclear weapons, the range of initial radiation is less than the range of lethal blast and thermal effects. For small weapons, direct radiation may be the lethal effect with the greatest range. For a one kiloton blast, initial radiation levels of at least rem extend out 0. For a one megaton surface blast, the rem exposure radius would be about 2.
Residual radiation is often termed fallout, and it can affect both the immediate blast area and areas farther away. Fallout is caused by particles that are scooped up when the nuclear fireball touches the earth. If the nuclear burst is high in the air, fallout is minimal. The scooped-up particles can be carried some distance by the wind before falling back to earth, and their concentration in any one location depends on local weather conditions.
Fallout can cause severe contamination to soil, vegetation and groundwater. A steady northwest wind, for example, blowing across a one megaton ground burst in Detroit, could carry enough residual radiation to inflict acute radiation sickness to exposed persons in Cleveland.
The residual radiation decays over time, by a factor of ten after seven hours, a factor of after 49 hours and a factor of 1, after two weeks. Depending on the conditions of the blast, radiation levels can persist above permissible peace time levels for months or years in areas around the explosion.
This can also be estimated as a ring inside which the mean lethal overpressure is approximately five pounds per square inch.
This is the amount of pressure needed to collapse a typical residence. Imagine that a nuclear weapon is detonated in Washington, D. Using the definition of lethal radius as the area inside which the mean overpressure is five pounds per square inch, the lethal radius for such an event with weapons of various yields can be calculated. Table 2 and the map figure display the five pounds per square inch radii for weapons with yields of one kiloton, 20 kiloton, kiloton and one megaton.
Table 2 - Five psi radii for various yield nuclear weapons Weapon Yield 5 psi radius km 1 kiloton 0. The radii given in Table 2 assume that the weapon detonates in air at the optimum height for creating damage. The bombs dropped on Hiroshima and Nagasaki, Japan, for example, exploded at a height of approximately 1, feet. Buildings in Washington, DC are limited to feet.
Third degree burns that cover more than 24 percent of the body will likely be fatal if people don't receive medical care immediately. Those distances are variable, depending not just on the weather, but also on what you're wearing - white clothes can reflect some of the energy of a blast, while darker clothes will absorb it.
That's unlikely to make much difference for those unfortunate enough to be at the centre of the explosion, though. The temperatures near the site of the bomb blast during the Hiroshima explosion were estimated to be , degrees Celsius , degrees Fahrenheit - which is times hotter than the temperature bodies are cremated at, so humans were almost instantly reduced to their most basic minerals.
But for those slightly further away from the centre of the blast, that's not what's most likely to kill you. As the video above explains , most of the energy released in a nuclear explosion is in the blast, which drives air away from the site of the explosion, creating sudden changes in air pressure that can crush objects and knock down buildings.
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