Bomb plutonium

Fermi s atomic pile was just a prototype. For manufacturing bomb plutonium, a plant was built at the tiny village of Hanford in Washington State. And so, drip by drip, the US war machine squeezed out its uranium-235 and plutonium, while the problem of how to build an atomic bomb was tackled by the physicists, chemists, and engineers at the Los Alamos complex in New Mexico. 

Many artificial (likely radioactive) isotopes can be created through nuclear reactions. Radioactive isotopes of iodine are used in medicine, while isotopes of plutonium are used in making atomic bombs. In many analytical applications, the ratio of occurrence of the isotopes is important. For example, it may be important to know the exact ratio of the abundances (relative amounts) of the isotopes 1, 2, and 3 in hydrogen. Such knowledge can be obtained through a mass spectrometric measurement of the isotope abundance ratio. 

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. 

Uses of Plutonium. The fissile isotope Pu had its first use in fission weapons, beginning with the Trinity test at Alamogordo, New Mexico, on July 16, 1945, followed soon thereafter by the "Litde Boy" bomb dropped on Nagasaki on August 9, 1945. Its weapons use was extended as triggers for thermonuclear weapons. This isotope is produced in and consumed as fuel in breeder reactors. The short-Hved isotope Tu has been used in radioisotope electrical generators in unmanned space sateUites, lunar and interplanetary spaceships, heart pacemakers, and (as Tu—Be alloy) neutron sources (23). 

Baker, R. D. "Preparation of Plutonium Metal by the Bomb Method," Los Alamos Scientific Laboratory, LA-473 (1946). 

Sohn, C. L. Thorn, C. W. Christensen, D. C. "Enchanced Production of Plutonium Metal Using Pu02 in the PuF4/Bomb Reduction Process," Los Alamos National Laboratory LA-UR-82-1230, May 1982. 

Half-lives span a very wide range (Table 17.5). Consider strontium-90, for which the half-life is 28 a. This nuclide is present in nuclear fallout, the fine dust that settles from clouds of airborne particles after the explosion of a nuclear bomb, and may also be present in the accidental release of radioactive materials into the air. Because it is chemically very similar to calcium, strontium may accompany that element through the environment and become incorporated into bones once there, it continues to emit radiation for many years. About 10 half-lives (for strontium-90, 280 a) must pass before the activity of a sample has fallen to 1/1000 of its initial value. Iodine-131, which was released in the accidental fire at the Chernobyl nuclear power plant, has a half-life of only 8.05 d, but it accumulates in the thyroid gland. Several cases of thyroid cancer have been linked to iodine-131 exposure from the accident. Plutonium-239 has a half-life of 24 ka (24000 years). Consequently, very long term storage facilities are required for plutonium waste, and land contaminated with plutonium cannot be inhabited again for thousands of years without expensive remediation efforts. 

Unstable, silvery metal. The element was first discovered in the fallout from the first hydrogen bomb on the Bikini Atoll (1952), later produced by neutron bombardment of plutonium. Half-lives of the isotopes range from 20 to 401 days. "Relatively short-lived" in comparison to Einstein s formula E=m-c2, which is valid forever. Only of scientific interest. 

Thorium, uranium, and plutonium are used for many things, from medicine to atomic bombs. When these elements break apart, they release large amounts of energy. Chemists and physicists are learning to control this atomic energy and make it do useful work. 

Plutonium from the Hanford Site was shipped to Los Alamos every 5 days, and enriched uranium was shipped to Los Alamos from Oak Ridge. At 5 30 a.m. on Monday, July 16, 1945, the U.S. tested the first plutonium bomb, named Trinity, at the White Sands Missile Range, New Mexico. The bomb exploded with a force of approximately 18.6 kilotons. After this test there was no longer any question that the plutonium bomb would work. 

Despite Germany s surrender, Japan continued to resist the unconditional surrender demanded by the Allied Forces. Knowing that the U.S. would shortly have enriched uranium and plutonium bombs ready for use enabled Truman to avoid extending Japan an offer of surrender that allowed the Emperor to continue to rule. On July 26, 1945, the Potsdam Declaration was issued via radio to Japan. President Truman, Chiang Kai-Shek of Nationalist China, and Winston Churchill of Great Britain called on the Japanese government to proclaim now the unconditional surrender of all Japanese armed forces. The alternative for Japan is prompt and utter destruction. 4 Japanese leadership rejected the declaration on July 29, 1945. 

For the purpose of this discussion, radiological materials that could be used in a terrorist attack are divided into three categories (1) bomb-grade nuclear material, (2) nuclear reactor fuel and associated waste products, and (3) industrial sources. Bomb-grade nuclear material includes concentrated plutonium and/or highly enriched uranium (>20% U-235) that may be used to build a nuclear weapon, assuming a terrorist group cannot or has not already secured an assembled weapon. 

Nuclear fuel and associated waste products also include plutonium and enriched uranium (<20% U-235) and associated waste or fission products that emit intense radiation and can pose significant threats if dispersed with conventional explosives (i.e., by a dirty bomb). Industrial sources include a range of devices used in geological investigation and radiography, and may also pose significant hazards if dispersed by a dirty bomb. Examples of radioactive materials that could be used in a dirty bomb include ... 

Table 2.1 lists specific radionuclides that may be present in nuclear fuel rods or industrial sources used to construct a dirty bomb. It also lists the radiological half-lives of each radionuclide, whether they are present in fresh or spent fuel rods, and their potential industrial applications. Note that the actual suites of isotopes for given fuel rods will vary depending on the origin and composition of the original fuel mixture. The uranium and plutonium isotopes found in fuel rods may also be found... 

Because the isotope uranium-235 is fissionable, meaning that it produces free neutrons that cause other atoms to split, it generates enough free neutrons to make it unstable. When the unstable U-235 reaches a critical mass of a few pounds, it produces a self-sustaining fission chain reaction that results in a rapid explosion with tremendous energy and becomes a nuclear (atomic) bomb. The first nuclear bombs were made of uranium and plutonium. Today, both of these fuels are used in reactors to produce electrical power. Moderators (control rods) in nuclear power reactors absorb some of the neutrons, which prevents the mass... 

Defense high-level wastes are those produced as a result of military research during the recovery of the uranium and plutonium used in making fission and fusion bombs. 

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