03-11-2005, 03:55 PM |
أحمد أمين
أحمد أمين
Registered: 07-27-2002
Total Posts: 3371
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The History of Nuclear Energy and (Sedan)
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Development of the Atomic Bomb Top Navigation The world entered the atomic age on December 2, 1942, at 3:25pm when a team of scientists led by Enrico Fermi (Photo) were the first in history to initiate a self sustaining nuclear chain reaction and control it. (Photo of Team) Fermi’s atomic pile as it was then known, was built on a squash court beneath the West Stands of Stagg Field, the athletic stadium of the University of Chicago. Fermi coined the term pile. The physicist and author Emilio Segre` stated "I thought for awhile that this term was used to refer to a source of nuclear energy in analogy with Volta’s use of the Italian term pila to denote his own great invention of a source of electrical energy. I was disillusioned by Fermi himself, who told me that he simply used the common English word pile as synonymous with heap." The means to the historic end of a sustained chain reaction was not much to look at, a 24 ½ foot square, 19 foot high stack of black graphite bricks covered on three sides by a gray cloth balloon. It had been assembled by football players from the University, who were hired by the scientists for their strength, in a disused 30 by 60 foot squash court with a balcony along one end. (Drawing)
Fermi’s experiment that day represented the culmination of years of research into the properties of uranium. It had long before been realized by scientists that it might be possible to build a bomb of tremendous power utilizing the fissioning of uranium. Many scientists around the world were working toward the achievement of a sustained nuclear reaction theoretically with that thought in the back of their minds. The world was at war, Hitler was on the move and those who were aware of the possibility of a weapon knew that German physicists had been conducting experiments aimed at that goal. Leo Szilard (Photo), a Hungarian physicist, in particular was afraid the Germans would produce a bomb first and, with fellow Hungarian physicist Edward Teller, approached Albert Einstein and asked him to warn the President of the danger. Einstein agreed to do so. In a letter to Franklin D. Roosevelt in August of 1939 Einstein told the President that "this new phenomenon [a nuclear chain reaction] would also lead to the construction of bombs, and it is conceivable - though much less certain - that extremely powerful bombs of a new type may thus be constructed".
Physicists repeatedly brought the idea of an atomic bomb to the attention of the military and other government offices in the United States and Great Britain with no real success. It was not until December 6, 1941, the day before the Japanese bombed Pearl Harbor that the final decision was taken to begin substantial financial and technical support of a program to produce the bomb. The first meeting of what was then called S-1 took place on December 18, 1941. The code name S-1 stood for Section One of the Office of Scientific Research and Development. In 1942 direction of the project was transferred to a Military Policy Committee made up of Brigadier General Wilhelm D. Styer, Admiral W.R. Purnell, Brigadier General Leslie Richard Groves (Photo), Dr. Vannevar Bush and Dr. James Conant, under the supervision of the head of the Army Corps of Engineers, Brehom Somervell. After August 13, 1942 the project became known as the Manhattan Engineer District or Manhattan Project. It was as part of the Manhattan Project that Enrico Fermi and his colleagues ushered the world into the atomic age.
The Physicist chosen to head the bomb project was Robert Oppenheimer (Photo), a California Professor of Theoretical Physics, who was appointed in July of 1943. The Army wanted an isolated place, far from population centers, due to the secrecy surrounding the project and the possible danger of the work. It was Oppenheimer who suggested Los Alamos New Mexico as the location for the lab to produce the bomb. He had vacationed there as a boy. A number of other facilities were built as parts of the vast project, the first at Oak Ridge, Tennessee. The land was acquired by General Groves in September 1942. The purpose of Oak Ridge, or the Clinton Engineer works, was to produce the Uranium 235 for the bomb. Both gaseous diffusion and electromagnetic isotope separation plants were built at Oak Ridge. The plant was finished and in production by September 1944. The second, the Hanford Engineer Works (Photos), began construction soon after the land was acquired in late January of 1943, but the piles were not begun until October due to a number of design questions. The purpose of the Hanford Works in Eastern Washington state was to produce Plutonium for the bomb effort. On September 26, 1944 the largest atomic pile ever built was loaded and ready. The reaction began propitiously only to die by the next morning. It was discovered that a hitherto unknown product of the reaction was poisoning the pile. After a redesign of the reactor it began producing December 17, 1944.
The primary purpose of the Manhattan Engineer District was not only to produce a workable atomic weapon but to do so before the Germans could manage to. That they succeeded in their undertaking was demonstrated at 05:29:45, on July 16, 1945 at a spot in the New Mexican desert code named Trinity. (Map of the Trinity Site) Located 210 miles South of the Manhattan Project laboratory at Los Alamos, Trinity was 24 acres of the Alamagordo Bombing Range, a region of dry scrub. The area had been known as Journada del Muerto, ‘The Journey of Death’ for its lack of water since the days of the early Spanish. It is now part of the White Sands Missile Range. (Photo of test) (photo of results of test) President Truman was at the Potsdam Conference at the time of the Trinity Test. The results were telegraphed to him on the evening of the second day of the conference. In a prearranged code, the message read "Operated on this morning. Diagnosis not yet complete, but results seem satisfactory and already exceed expectations. Local press release necessary as interest extends great distance. Dr. Groves pleased. He returns tomorrow. I will keep you posted" The bombs that were the result of the immense undertaking that was the Manhattan Project were used twice, on Hiroshima, Japan August 6, 1945, and on Nagasaki Japan August 9, 1945. The war ended with the Emperors announcement to the Japanese people on August 15, 1945, however, bomb production did not cease with the cease fire. There were new enemies to protect against and larger, more powerful, bombs to develop. The end of World War Two led to the beginning of the Cold War and signaled the start of the arms race. It was expected that the Russians would eventually have the bomb, but predictions ranged from five to ten years for them to reach the point of having a usable weapon. The fears of the United States government and military were heightened when Russia tested their atomic bomb in 1949, much sooner than most had hoped. A US B-29 discovered evidence of the test in August of that year accidentally, while conducting experiments in bomber crew protection. President Truman announced to the American public that the Soviet Union had tested an atomic bomb on September 23, 1949. Behind the scenes the development of ‘the super’ or fusion bomb began. The confession of Klaus Fuchs, a physicist of the Manhattan Project on January 27 1950 that he was a spy for the Soviets, in particular spurred the government on. President Truman announced on January 31 that the US would develop the super or hydrogen bomb. Support for the development of the super was by no means universal in the scientific community, Edward Teller was it’s chief proponent. Klaus Fuchs, as well as other Manhattan Project scientists, was alarmed at this announcement. He had known of Tellers pet project since 1946 and had given the information to the Soviets. Fuchs had felt that all the details of the A-bomb project should be shared with the Russians partially from his desire to avoid an escalating arms race. He was arrested on February 2, 1950 in London. His fellows at Los Alamos were shocked at the news, no one suspected.
Public opinion regarding the H-bomb, as it had come to be called, was negative and based in the same fear that the photographs of Hiroshima and Nagasaki had aroused. Many of the scientists who had been a part of the Manhattan Project also argued against the development of a Hell Bomb as many referred to it, arguments were in vain however, as the government was determined to build it. Teller and other proponents of the super had been at work for some time on the theory behind an H bomb. The idea was to create on earth the type of fusion reaction that produces the suns energy. With the start of the Korean War in June of 1950 many of the scientists who had been against the development of a thermonuclear bomb changed their minds and went back to weapons research, they felt it was their duty. The team at Los Alamos working on the super included Teller, Hans Bethe, Stan Ulam, John VonNewmann, and a number of other scientists who had previously worked on the atomic bomb.
There were a number of technical problems, the design was difficult to arrive at and the computations insisted on coming out differently than expected. The first set of calculations indicated that Tellers original premise wouldn't work. Stan Ulam came up with an alternate plan which proved to be the key to developing the super. A huge number of calculations remained however, and it took the efforts of a huge team of scientists to work on them. They despaired of finishing until John von Neumann’s new computer MANIAC came on line. Once the computer began working on the calculations things began to move quickly. Teller, who had never been comfortable with not being in charge, left Los Alamos in July 1952 for the brand new Lawrence Livermore Laboratory in Livermore, California. Work on the super, at this point mainly experimental verification of the calculations and assembly, continued without him. The device that was finally produced, a 65 ton behemoth code named Mike, was exploded on Eniwetok in the Marshall Islands in October 1952. Teller was not there, he was at his lab in California watching for the traces of the explosion on a seismograph. The US monopoly lasted until August 8, 1953 when the Soviets set off a ‘super’ of their own. the size of an island and had to be refrigerated. There was much consternation that ours was the size of an island and had to be refrigerated and theirs was a usable bomb. Research into the commercial, peaceful uses of atomic energy were begun after World War II. Wonders were predicted for the new technology. President Truman stated in his State of the Union Address of 1950 that "in the peaceful development of atomic energy we stand on the threshold of new wonders. The first experimental machines for producing useful power from atomic energy are now under construction. We have made only the first beginnings in this field, but in the perspective of history they may loom larger than the first airplane, or even the first tools that started man on the road to civilization". Associated as it was with the atomic bomb, atomic energy had a fairly negative connotation in the mind of the public. Pains were taken by the government to distance the plans for nuclear power from the visions of mushroom clouds. Harold Stassen, special assistant to President Eisenhower on disarmament told the Ladies Home Journal "The reactor is not, as some nervous people seem to fear, a pint sized bomb that is about to explode". The Atoms for Peace program emphasized that it was impossible for a nuclear plant to behave as a bomb would, it could not explode. President Eisenhower spoke to the General Assembly of the United Nations on December 8, 1953 and announced that "The United States knows that peaceful power from atomic energy is no dream of the future. That capability, already proved, is here now - today....[we must] hasten the day when fear of the atom will begin to disappear from the minds of the people and the governments of the East and West....This greatest of destructive forces can be developed into a great boon for the benefit of all mankind". (Full Text) The high hopes for future uses of atomic energy included more than electric power generation. A future was envisioned where the atom bomb itself would have peaceful uses. Plowshare was the name chosen for the program to develop nuclear high explosives for use in mining, earth moving, harbor building, canal digging, cutting tunnels for highways and railways and a number of other projects. Edward Teller presented Project Plowshare to the world at the Second International Conference on the Peaceful Uses of Atomic Energy held in Geneva in 1958. At one time many uses were suggested and testing was done at the Nevada test site with underground detonations. Such as the Project Sedan nuclear excavation experiment which produced a crater 1,286 feet in diameter and 323 feed deep, displacing 12 million tons of earth. The device used was 104 kilotons and was detonated at 635 feet beneath the surface on July 6, 1962. (Photo) Sedan was the second of Plowshares tests, the first, named Gnome, was set off December 10, 1961. Altogether there were 35 Plowshare experimental detonations between 1961 and 1973. In 1960 it was proposed that, with the help of powerful nuclear explosives, the Panama Canal could be excavated to become a sea level canal rather than the lock canal design which was resorted to due to the overwhelming quantities of rock involved. The new canal was to be called the Panatomic Canal. Legislation was enacted by Congress authorizing a commission to be appointed to study the possibility and the group carefully examined the possibilities and recommended 5 potential sites. Eventually the plan had to be dropped due to "prospective host country opposition to nuclear canal excavation." Over the course of time the imaginative ideas of Plowshare were found to be impractical, impossible or unfeasible one by one. The contamination problems were insurmountable and Plowshare faded away. The Atomic Energy Commission, which succeeded the Manhattan Engineer District as of January 1, 1947, did much to encourage the commercial use of nuclear reactors for the generation of electricity. Lewis L. Strauss, Chair of the AEC proclaimed that nuclear power would be "too cheap to meter". On August 8, 1955, Lewis Strauss, the head of the Atomic Energy Commission (AEC), spoke to the United Nations on the future of nuclear development. In 1946, Strauss left a highly successful banking practice to join the AEC, and under his advice an atomic monitoring system was built that detected the detonation of the first Soviet atomic bomb in 1949. In 1958, Strauss left the AEC and was appointed secretary of commerce by President Dwight Eisenhower. He held the office until 1959, when in a close vote, the Senate rejected his nomination, finding that he had once lied under oath.
The first small steps toward power production were made and on December 20, 1951 an experimental reactor produced enough power to light four 150 watt light bulbs. The Experimental Breeder Reactor or EBR I was constructed at the National Reactor Testing Station near Idaho Falls, Idaho by the Argonne National Laboratory of the University of Chicago, the lab that began with Fermi’s pile on the squash court. The next day EBR I was powered up and produced 100 watts of power. The Argonne Lab also designed the first reactor to provide an entire towns electric power. BORAX III began producing power for Arco, Idaho on July 17, 1955. The AEC sponsored a pilot project with Duquesne Light Co. in Shippingport, Pennsylvania to build a 60 megawatt breeder reactor plant which opened in 1957 as a demonstration program. The plant was designed by Westinghouse and was a PWR originally developed by Admiral Hyman Rickover’s navy program for submarine propulsion. Ground breaking for the project was held on September 6, 1954. It was part of a Power Demonstration program designed to stimulate the construction of nuclear power plants by private utilities. In fact “liberal aid was offered to any utility prepared to put up a plant, in the for of research and development assistance and waiver of fuel inventory charges for the first five years of plant operation”. This was the first American commercial reactor licensed. It was ordered in 1953 and operated until 1982. Industry seemed reticent however, no plants had been ordered despite the AEC’s encouragement and research. Finally in 1957 Chairman Strauss said "It is the Commissions policy to give industry the first opportunity to undertake the construction of power reactors. However, if industry does not, within a reasonable time, undertake to build types of reactors which are considered promising, the Commission will take steps to build the reactors on it’s own initiative".
The first wholly commercial power plant, modeled after the BORAX III experimental reactor was ordered in 1955 and built in 1959 by Commonwealth Edison in Morris, Illinois. The plant, known as Dresden Unit One was a 200 megawatt, Dual Cycle Boiling Water Reactor constructed for $18 million and opened in 1960. It was designed by General Electric and operated until 1979 when it was shut down. The next plants increased steadily in their power output ratings through the 1960's and 1970's, peaking in the 1100-1200 megawatt range in the 1980's. Unfortunately the early promises of inexpensive electrical power have not been proven out by the US experience. Plagued by cost overruns, bad press, extended outages and expensive repairs, nuclear power has proven to be much less economical than originally believed. The average nuclear plant in the early 1970's cost $170 million, the same size plant completed in 1983 cost $1.7 billion, and, by the late 1980's, $5 billion. “Time from project initiation to ground breaking was 16 months in 1967, 32 months in 1972 and 54 months in 1980". In addition, in the United States nuclear power plants are individually custom designed, this makes it necessary to custom fabricate all the parts which is more expensive. The cost of building the plant and maintaining it add to the cost of power which is higher for nuclear than other fuels. No new plants have been ordered since 1974, 97 of those ordered were canceled, and none are slated for construction in the United States, although approximately 108 plants are in operation at present. http://nuclearhistory.tripod.com/history.html
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