Реферат на тему Nuclear Energy 2 Essay Research Paper
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Nuclear Energy 2 Essay, Research Paper
Scientists discovered nuclear energy at the end of the nineteenth century. Within fifty years it became a decisive factor in our war with Japan and has affected international arms policies ever since.
The study of nuclear energy began in the nineteenth century when Marie and Pierre Curie discovered the radioactive elements radium and polonium. Before this only uranium and thorium were the only radioactive elements that were known. Radium and polonium were hundreds of times more radioactive than uranium. The Curies won the 1903 Nobel Prize in physics for these discoveries. Seven years later Marie Curie won the Nobel Prize in chemistry for refining radium. She was the first person to win the Nobel Prize twice.
Soon after the Curies made their discoveries, scientists discovered the radioactive element actinium. By 1912, thirty radioactive elements had been discovered.
In 1905, Albert Einstein developed a theory about the relationship of mass and energy. The formula, E=mc2 is probably the most famous outcome from Einstein’s theory of relativity. The formula states that Energy (E) equals mass (m) times the speed of light squared. In essence, it means mass is just one form of energy. Since the speed of light is an enormous number, 186,000 miles per second, and in the equation it is squared, a small amount of mass can be converted to a phenomenal amount of energy. Nuclear reactors are based around this theory because small amounts of mass can produce large amounts of energy.
In December 1938, two German scientist demonstrated nuclear fission. These two scientists, Otto Hahn and Fritz Strassman, found they could split the nucleus of a uranium atom by bombarding it with neutrons, which are the uncharged part of atoms. As the uranium nucleus splits, some of its mass is converted to energy by Einstein’s Law. This discovery spread through the scientific community very rapidly. Other scientists noted that the fission of one uranium atom gave off extra neutrons which could in turn split other uranium atoms, starting a large chain reaction. This process could either control the chain reaction to produce unlimited energy for everyday use or the “atomic bomb”.
An atomic bomb works by fusing two pieces of refined uranium in a short time. The uranium reaches a critical mass, which is the mass necessary to sustain a chain reaction. This is relatively safe until the point of critical mass. The two pieces of uranium are placed far enough apart so that critical mass will not be reached. When detonation is desired the two pieces of uranium of are fired together using explosive charges achieving critical mass. A neutron chain reaction starts because extra neutrons are released in each uranium atom fission. These extra neutrons collide with the surrounding uranium atoms and produce more fissions and neutrons. This process is soon out of control producing a very deadly explosion.
It was soon realized that even more powerful forms of nuclear energy could be produced with the nuclear fusion reactions, where light elements are fused releasing 100 to 1000 times more energy than released in fission. This is the basis of the hydrogen bomb.
On August 2, 1939, Albert Einstein sent a letter to President Roosevelt informing him of German atomic research and the potential threat of a bomb. He also tried to encourage Roosevelt to take up American atomic research. In October, 1939, Roosevelt approved uranium research in the United States. This, among many other decisions, resulted in the Manhattan Project. Within two years, Japan bombed Pearl Harbor, and the United States entered World War II.
In September 1942 the Manhattan Project was formed to covertly build the atom bomb before the Germans. The Army appointed General Leslie Groves, the engineer responsible for building the Pentagon, to head the efforts. At first, the research took place at several university laboratories. Soon after Enrico Fermi achieved a sustainable nuclear chain reaction at the University of Chicago, the Manhattan Project built a top-secret complex of nuclear production and research facilities across the country, hiring 300,000. Secrecy was so complete that the employees did not know what they were working on until they heard about the bombing of Hiroshima, Japan on August 6, 1945. Six days later President Truman released the Smyth Report to the American Public. It contained information of the Manhattan Project, without revealing any atomic secrets. The public was surprised to learn of the operation with the payroll, facilities, and labor force comparable in size to the American automobile industry.
In November 1942, the top-secret laboratory was built deep in the mountains of Los Alamos, New Mexico. Robert Oppenheimer, a theoretical physicist from the University of California, Berkeley, was appointed as the director. Oppenheimer assembled a team of scientists to make an nuclear device small enough to be delivered by an airplane. The scientist were not aware that they were working on an atom bomb, they were only told that they were working on a project that might end the war. The employees and their families were kept on site and not able to leave unless a major emergency occurred. Nearly 5,000 people lived and worked at Los Alamos by the end of the war.
One month later, Enrico Fermi demonstrated the first nuclear chain reaction. Fermi and his associates built a crude nuclear reactor that they named Chicago Pile 1. On December 2, 1942, Fermi announced that the reaction was self-sustaining.
In 1942 and 1943, the Clinton Engineer Works was built to produce refined uranium. It was built in a town west of Knoxville, Tennessee, known as Oak Ridge, Tennessee. By the end of the war, Oak Ridge was the fifth largest town in Tennessee. The Clinton Engineer Works was Renamed the Oak Ridge National Laboratory after World War II.
In July of 1945, The United States exploded the first atomic device at a site near Alamogordo, New Mexico. The released blast was equivalent to 18,600 tons of TNT. A short while later, at the Potsdam Conference ending world war II in Europe, the Allied powers discussed what should be done about Japan and the land regained from Germany. President Truman was informed about the successful Trinity test and that a bomb could be formed by early August. Truman and Prime Minister of England Winston Churchill decided that the bomb would make the Japanese surrender without the help of the Russians. The Japanese were told that if they did not surrender they would face “prompt and utter destruction.” Japan refused.
The next month of that same year, The United States dropped atomic bombs on Hiroshima and Nagasaki, Japan. On August 6, 1945, a B-29 bomber, known as the Enola Gay, released a 9,700 pound uranium bomb, nicknamed Little Boy, on the city of Hiroshima, killing and wounding a total of 140,000 people and destroying everything in a five mile radius. President Truman warned Japan that if they did not surrender that the United States would attack another target with equally devastating results. Japan again refused. Three days later on August 9, 1945, another B-29 bomber, Named Bock’s Car, was sent to bomb Kokura Arsenal. However, the pilot switched to the his secondary target, Nagasaki, because of the bad weather over Kokura. Nagasaki was the home of a Mitsubishi torpedo manufacturing plant. Bock’s Car dropped a 10,000-pound plutonium bomb, nicknamed Fat Man, over the slopes of Nagasaki, killing and wounding a total of 100,000 and destroying three square miles of the city. Japan surrendered on August 14, 1945.
In July 1946, the Atomic Energy Act was passed, establishing the Atomic Energy Commission (AEC), which replaced the Manhattan Project on December 31, 1946. The act placed control of atomic energy in civilian hands. The act stated that atomic energy should be directed “toward improving public welfare, increasing the standard of living, strengthening free competition among private companies and cementing world peace.” However, the act prohibited private companies or individuals from owning nuclear material and patenting inventions related to atomic energy. The act also restricted information on using nuclear materials to produce energy as well as on designing, making, and using atomic weapons.
Three years later, the Soviet Union detonated its first atomic device. American nuclear scientist had not suspected it to be so soon, which shook the American public’s sense of security. Thousands of Americans volunteered to scan the skies with binoculars for Soviet bombers as part of “Operation Skywatch.” This and the Communist Revolution in China caused President Truman to call for the United States to build up its conventional and nuclear forces to stop the spread of Soviet influence on the world.
These matters and more caused the United States and the Soviet Union to enter a nuclear arms race which lasted until the 1980’s when President Ronald Reagan announced the Strategic Defense Initiative (SDI), dubbed Star Wars by the press, a satellite-based defense system that would destroy incoming missiles and warheads in space. In, 1985, Mikhail Gorbachev became the leader of the Soviet Union. He made a plan for the United States and the Soviet Union to cut down their nuclear arms. It also called for the end of the space strike weapons (Star Wars). This among other things ended the Nuclear Arms Race.
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