The Atomic Bomb

Another problem with nuclear power plants is their radioactive waste production. The United States has debated where and how to permanently store nuclear wastes. In July 2002, an underground site was authorized at Yucca Mountain, Nevada, about 90 miles north of Las Vegas. The Yucca Mountain facility was closed in 2009. A permanent site for nuclear waste storage has not yet been decided upon. 

In the United States, reactors designed for commercial power production use uranium oxide, UsOs, that is enriched with the relatively scarce fissionable U-235 isotope. Because the supply of U-235 is limited, a new type of reactor known as the breeder reactor has been developed. Breeder reactors produce additional fissionable material at the same time that the fission reaction is occurring. In a breeder reactor, excess neutrons convert nonfissionable isotopes, such as U-238 or Th-232, to fissionable isotopes, Pu-239 or U-233, as shown below  

These transmutations make it possible to greatly extend the supply of fuel for nuclear reactors. No breeder reactors are presently in commercial operation in the United States, but a number of them are being operated in Europe and Great Britain. 

The atomic bomb is a fission bomb it operates on the principle of a very fast chain reaction that releases a tremendous amount of energy. An atomic bomb and a nuclear reactor both depend on self-sustaining nuclear fission chain reactions. The essential difference is that in a bomb the fission is wild, or uncontrolled, whereas in a nuclear reactor the fission is moderated and carefully controlled. A minimum critical mass of fissionable material is needed for a bomb otherwise a major explosion will not occur. When a quantity smaller than the critical mass is used, too many neutrons formed in the fission step escape without combining with another nucleus, and a chain reaction does not occur. Therefore the fissionable material of an atomic bomb must be stored as two or more subcritical masses and brought together to form the critical mass at the desired time of explosion. The temperature developed in an atomic bomb is believed to be about 10 million degrees Celsius. 

The hazards of an atomic bomb explosion include not only shock waves from the explosive pressure and tremendous heat, but also intense radiation in the form of alpha particles, beta particles, gamma rays, and ultraviolet rays. Gamma rays and X-rays can penetrate deeply into the body, causing burns, sterilization, and gene mutation, which can adversely affect future generations. Both radioactive fission products 

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The rapid fission of a mass of or another heavy nucleus is the principle of the atomic bomb, the energy liberated being the destructive power. For useful energy the reaction has to be moderated this is done in a reactor where moderators such as water, heavy water, graphite, beryllium, etc., reduce the number of neutrons and slow those present to the most useful energies. The heat produced in a reactor is removed by normal heat-exchange methods. The neutrons in a reactor may be used for the formation of new isotopes, e.g. the transuranic elements, further fissile materials ( °Pu from or of the... 

By far the most interesting historical work on the atomic bomb I know of - C. P. Snow... 

Another impetus to expansion of this field was the advent of World War 11 and the development of the atomic bomb. The desired isotope of uranium, in the form of UF was prepared by a gaseous diffusion separation process of the mixed isotopes (see Fluorine). UF is extremely reactive and required contact with inert organic materials as process seals and greases. The wartime Manhattan Project successfully developed a family of stable materials for UF service. These early materials later evolved into the current fluorochemical and fluoropolymer materials industry. A detailed description of the fluorine research performed on the Manhattan Project has been pubUshed (2). 

S. Groueff, Manhattan Project The Untold Story of the Making of the Atomic Bomb, Bantam Books, New York, 1967, pp. 211—219. 

The determination of critical si2e or mass of nuclear fuel is important for safety reasons. In the design of the atom bombs at Los Alamos, it was cmcial to know the critical mass, ie, that amount of highly enriched uranium or plutonium that would permit a chain reaction. A variety of assembhes were constmcted. Eor example, a bare metal sphere was found to have a critical mass of approximately 50 kg, whereas a natural uranium reflected 235u sphere had a critical mass of only 16 kg. 

Polychlorotrifluoroethylene was the first fluorinated polymer to be produced on an experimental scale and polymers were used in Germany and in the United States early in World War II. PCTFE was used, in particular, in connection with the atomic bomb project in the handling of corrosive materials such as uranium hexafluoride. 

In the 1930s, the world s greatest migration of scientists took place under the lash of Nazism. It has sometimes been asserted that Hitler may have lost the War because of the talent he forced to flee, and that the American development of the atomic bomb that shortened the War so drastically might have been much slower without that migration. Other, less cataclysmic, consequences also flowed from the migration, and this Section is devoted to one of them. 

There are numerous early scientific works concerning the presence of shock waves and the influence of explosions, impacts, and shock waves on matter. The earliest work, however, did not lead to a delineation of the phenomenon as a distinct scientific enterprise. This distinction rests with a group of visionary scientists assembled at Los Alamos for the development of the atomic bomb during World War II. Having learned the methods and developed the technology to explosively load samples in a precise and reproducible manner, they realized that they had in their hands, for the first time, the ability to study matter in an entirely new range of pressure. After several precursor publications beginning in 1955, the existence of the new scientific field was reported to the world in the classic work by Melvin Rice, John Walsh, and... 

Rhodes, R. (1987). The Making of the Atomic Bomb. New York Simon and Schuster. 

The step from nuclear fission to a nuclear chain reaction and the atomic bomb was, in principle, quite straightfoiward. In practice, however, it consumed more time and money than was ever foreseen. Although it was her basic insight that eventually led to the fission bomb dropped on Hiroshima, Meitner refused to work on the bomb and, for humanitarian reasons, hoped that it would not work. 

World War II was ultimately a contest between economies, and victories were a direct result of effective resource mobilization. The atomic bombs dropped on Hiroshima and Nagasaki in August 1945 released a tremendous amount of energy in the form of heat and radiation the development of that weapon... 

Opinion polls showed that Aunerican anxiety about the atomic bomb ebbed and flowed in response to geopolitical events. Concerns ran high in the late 1940s in the wake of the atomic bombings of Japan... 

In the 1950s, widespread anxieties about the atomic bomb m the 1950s spurred few into action. One notable exception in the United States was the Greater St. Louis Committee for Nuclear Information, founded by biologist Bari-y Commoner and other scientists... 

A nuclear fission explosion. Such a dramatic and destructive release of energy had never been seen before the development of the "atomic bomb" during World War II. 

Notice from the fission equations written above that two to four neutrons are produced by fission for every one consumed. Once a few atoms of uranium-235 split, the neutrons produced can bring about the fission of many more uranium-235 atoms. This creates the possibility of a chain reaction, whose rate increases exponentially with time. This is precisely what happens in the atomic bomb. The energy evolved in successive fissions escalates to give a tremendous explosion within a few seconds. 

The potential of nuclear fission was first realized in the atomic bomb. In 1945, the United States dropped two bombs of unprecedented power, one on Hiroshima and the other on Nagasaki, Japan. Both were fission weapons. 

One can think of mass as "frozen energy." As this calculation shows, a tiny bit of mass can liberate an enormous amount of energy. Less than a teaspoon of it can—and did—level a sizable city, as was demonstrated dramatically by the atomic bomb dropped on Hiroshima in 1945. 

Yamamoto M, Komura K, Sakanoue M, et al. 1985. Pu isotopes,241 Am and 137Cs in soils from the atomic bombed areas in Nagasaki and Hiroshima. J Radiat Res 26 211-223. 

Otake M, Schull W. 1984. Mental retardation in children exposed in utero to the atomic bombs A reassessment. Technical Report RERF TR 1-83, Radiation Effects Research Foundation, Japan. 

Heisenberg, the atom-bomb man. The uncertainty principle. The more accurately you measure the position of something at a particular moment, the less accurately you can measure where it s going the velocity—the trajectory. At least, that s roughly it. My father could tell you more. ... 

Lorna McCleary Patterson. Sea Ranch, California, Oct. 4-5, 1997. Source for petition to Groves and the day the atomic bomb was dropped penance for Oak Ridge joggers hair Argonne and heart attack seasick running MIT sabbatical and Pit Diggers cartoons. 

A little girl of 1 7 in a mental hospital told me she was terrified because the atom bomb was inside her. That is a delusion. The statesmen of the world who boast and threaten that they have Doomsday weapons are far more dangerous and far more estranged from reality than many of the people on whom the label "psychotic" is fixed. 

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