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Text Box: Component Two
HISTORY: 
     In August of 1942, a microscopic sample of plutonium was first isolated by Glenn Seaborg as part of the Manhattan Project. These first tiny quantities were not created in a reactor, but instead by the irradiation of uranyl nitrate solution by the cyclotron at the University of California in Berkeley, US. On December 2, 1942, at 3:25pm, a team of scientists led by Enrico Fermi  were the first in history to initiate a self sustaining nuclear chain reaction and control it. 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¨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, 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, 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, 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, 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 on December 17, 1944. 
     On February 2, 1945, Los Alamos received its first plutonium. Plutonium is a highly carcinogenic, radioactive substance which does not exist in the natural environment and is only produced artificially in nuclear reactors. It is made by the irradiation with neutrons of uranium-238 in military as well as civilian nuclear reactors. Plutonium has 15 isotopes with mass numbers ranging from 232 to 246. Only two plutonium isotopes have applications:  
- plutonium-238 is used to make compact thermo-electric generators (for example satellites); 
- plutonium-239 is used for nuclear electricity.  
     The formed plutonium is contained inside the spent fuel rods. The longer the fuel is inside the reactor, the more contaminant plutonium isotopes are formed. In military reactors the fuel is replaced after some weeks in order to obtain as much plutonium-239 as possible. In commercial reactors this is done after three to four years. 
Plutonium production
     During reprocessing, plutonium is separated from spent nuclear fuel. The plutonium was produced in dedicated military reactors with low-burn-up fuel. Fuel in power reactors is irradiated for longer periods to reach a higher burn-up, because the fuel irradiation generates the heat for the electricity production. The military purpose is the production of plutonium and therefore the burn-up is kept low to produce a plutonium-239 as pure as possible. It is important to keep the presence of higher isotopes, particularly plutonium-240, to a minimum. Reprocessing plants handle spent fuel mechanically and chemically in order to separate plutonium from mainly uranium and other fission products.  
Civil Plutonium production
     Civil reprocessing was applied on an experimental scale from 1966-1974 by the Eurochemic reprocessing plant in Dessel, Belgium, and from 1972-1990 by the WAK in Karlsruhe, Germany. From the late 1960s on, large scale reprocessing of spent fuel from commercial nuclear power plants started: in France the Marcoule plant UP1 (1958-1997) and La Hague UP2 (1966-1976); in the UK Windscale B-204 from 1969-1973; and in the US, West Valley (1966-1972).9 The two largest reprocessors and plutonium companies in the world are British Nuclear Fuel Ltd. (BNFL) and the French Compagnie G└n└rale des Mati┬res Nucl└aires (Cog└ma). Based on the nominal production capacity of 1600 MT/year for La Hague and 900 MT/y for Sellafield the maximum Pu production in the next 20 years will be about 500,000 kg Pu on the assumption of an average of 1% Pu in the spent fuel.  
     At present, about half of the annual plutonium production in civil nuclear fuel is separated in reprocessing plants. Each year about 60,000 kg of plutonium is produced in nuclear reactors, from which about half (some 33,400 kg) of plutonium is separated.
     The estimated cumulative civil plutonium production in civil nuclear reactors until the end of 1995 is about a million kg of plutonium, from which about 800,000 kg is inside the spent fuel. About 190,000 kg of plutonium has been reprocessed. Of this plutonium 141,000 kg is stockpiled and 49,000 kg is recycled as MOX (Mixed OXide) fuel in LWRs and FBRs.14
     The amount of civil separated plutonium will increase enormously. The next 20 years the cumulative production of civil reprocessing plants will be about 600,000 kg of plutonium. 
 
SCIENTISTS:
Glenn Theodore Seaborg
     (1912C1999) was involved in identifying nine transuranium elements (94 through 102), and he served as chairman of the United States Atomic Energy Commission (AEC) from 1961 to 1971. In 1951 he shared the Nobel Prize in chemistry with the physicist Edwin M. McMillan.  
     Born in Michigan, Seaborg earned his bachelor's degree at the University of California at Los Angeles and his doctorate in chemistry from the University of California at Berkeley. He then served as research assistant to G. N. Lewis and eventually became chancellor of the university. He worked away from Berkeley during two significant periods: once to participate in the Manhattan Project at the University of Chicago from 1942 to 1946 and then again to chair the AEC!from which he returned to Berkeley. 
     In 1940 Edwin McMillan, assisted by Philip Abelson (later editor of Science magazine), confirmed and elucidated the phenomenon of nuclear fission announced by Otto Hahn and Fritz Strassmann in 1939. Specifically, he identified element 93, neptunium, among the fission products of uranium that was bombarded with neutrons produced from deuterons using the small (27-inch) cyclotron at Berkeley. McMillan also predicted the existence of element 94, plutonium, which he expected to find among the products of uranium under direct deuteron bombardment. McMillan, however, was suddenly called away to do war work and eventually joined the program at Los Alamos to build nuclear bombs. After World War II, his scientific reputation was enhanced by his critical contributions to the theory of particle accelerators.  
     Seaborg and his associates, who took over McMillan's project, soon found plutonium with a mass number of 238. Further research led to the production of isotope 239 in early 1941 in very small quantities. Plutonium 239 was shown to be fissionable by bombardment with slow neutrons and therefore became the newest material from which a nuclear bomb could be constructed. Up to that time scientists had known only of uranium 235 for this purpose. Seaborg then joined the Manhattan Project to work on the plan for producing sufficient plutonium 239 for a bomb!the one that was dropped on Nagasaki. Even before the war ended, he turned his attention to the production of further transuranium elements, developing the actinide transition series in the periodic table.  
     At the AEC, Seaborg became deeply involved in both arms control and nuclear regulatory affairs!attempting to manage the power of the atomic nucleus that his scientific work had revealed. Among chemists he has been unusual in writing histories of the epic developments in which he was involved so that the public can be the wiser for his experiences. With Benjamin S. Loeb he has written a historical series, the first of which was Kennedy, Khrushchev, and the Test Ban (1981). 
Ernest Orlando Lawrence 
     Lawrence invents the cyclotron: 1931
     When Ernest Orlando Lawrence (1901-1958) got his PhD in physics, the hottest topic was bombarding the atom's nucleus to see what new particles it might produce. Ernest Rutherford had only recently shown that striking the atom of one element could make it emit electrons and turn into a different element.
     Lawrence joined the physics faculty of the University of California (Berkeley) in 1928 and got intrigued with this new physics. So far, people had used alpha particles (the product of natural radioactivity) and protons (hydrogen atoms, containing a positive charge of 1) to bombard other atoms. But they had about exhausted that field of research. To learn more, they needed an artificial way to accelerate these particles to greater energy. Several accelerators were invented to give the bombarding particle a huge "kick" of electric potential. But it seemed that you'd need a kick of about 1 million volts to get the required acceleration, and making a machine to withstand that power was nearly impossible.
     Around this time, Lawrence happened to read a German paper describing a linear accelerator that boosted a particle's energy in steps using alternating electric fields. This did increase the particle's speed but to really get it up to the desired energy, the accelerator would have had to be impractically long. Lawrence knew that a magnetic field would deflect the charged particles into a curved path. By making the particles go in a spiral, he could boost their energy bit by bit each time they circled an electrode. The circular machine could fit in one room. The particles would spiral outward as they gained more energy, and when they were moving fast enough, they'd shoot out of the device with amazing force into a collector. 
     The university gave Lawrence the go-ahead to build what he called the cyclotron in 1930. With some graduate students, he tried a number of different set-ups. They had success using electrodes, a radio frequency oscillator producing 10 watts, a vacuum, hydrogen ions, and a 10 cm electromagnet. The whole contraption was quite small. With a larger magnet, Lawrence's team was able to produce 80,000 electron volts in 1931, and later the same year, with a 25 cm cyclotron, 1 million electron volts. Cyclotrons got successively larger, with new and different capacities. A 69 cm cyclotron could accelerate ions containing both protons and neutrons. With this, researchers produced artificial radioisotopes like technicium and carbon-14 used in medicine and tracer research. In 1939, a 152 cm device was being used for medical purposes, and Lawrence won the Nobel Prize in physics. Work was begun on a 467 cm machine in 1940, but World War II interrupted its development. Lawrence's team turned its attention to producing the uranium-235 needed for the atomic bomb.
     The development of the cyclotron and the growth of Lawrence's Radiation Laboratory had tremendous implications for science and the way it's done. This new tool could probe the atom's nucleus and offered applications in medicine and chemical research. It launched the modern era of high-energy physics. But it also launched the era of "big science"-- a new way of organizing scientific work. To feed and care for these increasingly large, complex, and expensive tools required more staff and above all, more money. Governments and corporations saw they had a stake in such research and stepped in as funders. 
     Ernest Lawrence died in 1958. In 1961, element 103 was discovered and named "lawrencium" in his honor.
 USE OF PLUTONIUM REPROCESSING:
     Fossil fuels are quickly diminishing, nuclear energy is surfacing as the major producer of electricity and energy in the world. However, we all know of its downside. Along with the huge amounts of energy also comes huge amounts of radioactive waste products that are harmful to the environment. This is where plutonium reprocessing comes in. By separating out a large portion of this waste, plutonium-239, not only are we provided with more fuel (especially of the type MOX which uses uranium and reprocessed plutonium), but we also significantly reduce the amount of waste that gets buried into our earth.
     The direct disposal of spent fuel which the United States is promoting will not serve for the closing of a nuclear fuel cycle. When environmental issues and greenhouse effects are considered in the context of global implications, the question remains whether it is advisable or not for industrialized nations to continue using fossil fuel forever. Bring plutonium-239 reprocessing into the cycle will wean the world away from the global dangers heading our way.
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
 
 
 
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