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A-Bomb(A) Essay, Research Paper

Atom bomb nuclear weapon manhattan project albert einsteinJust before the beginning of World War II, Albert Einstein wrote a letter to President Franklin D. Roosevelt. Urged by Hungarian-born physicists Leo Szilard, Eugene Wingner, and Edward Teller,Einstein told Roosevelt about Nazi German efforts to purify Uranium-235 which might be used tobuild an atomic bomb. Shortly after that the United States Government began work on theManhattan Project. The Manhattan Project was the code name for the United States effort todevelop the atomic bomb before the Germans did. “The first successful experiments in splitting auranium atom had been carried out in the autumn of 1938 at the Kaiser Wilhelm Institute inBerlin”(Groueff 9) just after Einstein wrote his letter. So the race was on. Major General WilhelmD. Styer called the Manhattan Project “the most important job in the war . . . an all-out effort tobuild an atomic bomb.”(Groueff 5) It turned out to be the biggest development in warfare andscience’s biggest development this century. The most complicated issue to be addressed by the scientists working on the Manhattan Projectwas “the production of ample amounts of ‘enriched’ uranium to sustain a chain reaction.”(Outlaw 2)At the time, Uranium-235 was hard to extract. Of the Uranium ore mined, only about 1/500 th ofit ended up as Uranium metal. Of the Uranium metal, “the fissionable isotope of Uranium(Uranium- 235) is relatively rare, occurring in Uranium at a ratio of 1 to 139.”(Szasz 15)Separating the one part Uranium-235 from the 139 parts Uranium-238 proved to be a challenge. “No ordinary chemical extraction could separate the two isotopes. Only mechanical methodscould effectively separate U-235 from U-238.”(2) Scientists at Columbia University solved thisdifficult problem. A “massive enrichment laboratory/plant”(Outlaw 2) was built at Oak Ridge, Tennessee. H. C. Urey, his associates, and colleagues at Columbia University designed a system that “worked onthe principle of gaseous diffusion.”(2) After this process was completed, “Ernest O. Lawrence(inventor of the Cyclotron) at the University of California in Berkeley implemented a processinvolving magnetic separation of the two isotopes.”(2) Finally, a gas centrifuge was used to furtherseparate the Uranium-235 from the Uranium-238. The Uranium-238 is forced to the bottombecause it had more mass than the Uranium-235. “In this manner uranium-235 was enriched fromits normal 0.7% to weapons grade of more than 90%.”(Grolier 5)This Uranium was then transported to “the Los Alamos, N. Mex., laboratory headed by J. RobertOppenheimer.”(Grolier 5) “Oppenheimer was the major force behind the Manhattan Project. Heliterally ran the show and saw to it that all of the great minds working on this project made theirbrainstorms work. He oversaw the entire project from its conception to its completion.”(Outlaw 3)Once the purified Uranium reached New Mexico, it was made into the components of a gun-typeatomic weapon. “Two pieces of U-235, individually not large enough to sustain a chain reaction,were brought together rapidly in a gun barrel to form a supercritical mass that explodedinstantaneously.”(Grolier 5) “It was originally nicknamed ‘Thin Man’(after Roosevelt, but laterrenamed ‘Little Boy’ (for nobody) when technical changes shortened the proposed gunbarrel.”(Szasz 25) The scientists were so confident that the gun-type atomic bomb would work”no test was conducted, and it was first employed in military action over Hiroshima, Japan, onAug. 6, 1945.”(Grolier 5)Before the Uranium-235 “Little Boy” bomb had been developed to the “point of seeming assuredof success,”(Grolier 5) another bomb was proposed. The Uranium-238 that had been earlier ruledout as an option was being looked at. It could capture a free neutron without fissioning andbecome Uranium-239. “But the Uranium-239 thus produced is unstable (radioactive) and decaysfirst to neptunium-239 and then to plutonium-239.”(Grolier 5) This proved to be useful becausethe newly created plutonium-239 is fissionable and it can “be separated from uranium by chemicaltechniques,”(6) which would be far simpler than the physical processes to separate theUranium-235 from the Uranium-238. Once again the University of Chicago, under Enrico Fermi’s direction built the first reactor. “Thisled to the construction of five large reactors at Hanford, Wash., where U-238 was irradiated withneutrons and transmuted into plutonium.”(6) The plutonium was sent to Los Alamos. The problem to overcome in the development of the plutonium bomb was an isotope of plutonium. The scientists feared this isotope would cause premature detonation and most of the plutoniumwould blow apart before it could all fission. “To overcome this so-called ‘defect of nature, ‘ theplutonium had to be brought into a supercritical mass far faster than conventional ballistics couldachieve.”(Grolier 6)Physicist Seth Neddermeyer and mathematician John von Neumann devised the theory of”implosion.” A subcritical sphere of plutonium was surrounded by chemical high-explosives. The5,300 pounds of explosives were all “carefully shaped as ‘lenses.’ When these were detonated,they focused the blast wave so as to compress the plutonium instantly into a supercriticalmass.”(Szasz 25) This was much more complex, and many people doubted that it would work. There was a debate at Los Alamos about whether to test the new plutonium ‘implosion’ bombbefore it was actually dropped. “Harvard explosives expert George B. Kistiakowsky andOppenheimer both argued for such a test, but initially Groves was opposed. He was afraid that ifthe test failed, the precious plutonium would be scattered all across the countryside.”(Szasz 26)Brigadier General Leslie R. Groves, the man the army placed in charge, was eventually persuaded. Hanford’s

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