How does nuclear energy work? Is radiation a risk? Find out the difference between nuclear fission and fusion, how uranium fuels the process, and the pros and cons of this alternative energy source. Types of nuclear reactors In the U. Nuclear energy history The idea of nuclear power began in the s , when physicist Enrico Fermi first showed that neutrons could split atoms.
Nuclear power, climate change, and future designs Nuclear power isn't considered renewable energy , given its dependence on a mined, finite resource, but because operating reactors do not emit any of the greenhouse gases that contribute to global warming , proponents say it should be considered a climate change solution.
Nuclear power risks When arguing against nuclear power, opponents point to the problems of long-lived nuclear waste and the specter of rare but devastating nuclear accidents such as those at Chernobyl in and Fukushima Daiichi in Share Tweet Email.
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Meet the people trying to help. Animals Whales eat three times more than previously thought. Environment Planet Possible India bets its energy future on solar—in ways both small and big. Environment As the EU targets emissions cuts, this country has a coal problem. He went on to discover gamma radiation, and even theorized the existence of neutrons in , despite having absolutely no evidence of their existence. Neutrons would eventually be discovered in These foundational discoveries formed the basis for what would grow into the industry of nuclear energy production.
In , German scientists Otto Hann and Fritz Strassman shot neutrons at uranium atoms and discovered that a significant amount of energy was being released. With the help of Lise Meitner and Otto Frisch, they were able to explain that what they had observed was the splitting of the atom through fission.
By , physicists Leo Szilard and Enrico Fermi theorized that fission reactions could be used to create an explosion through a massive chain reaction. Szilard and a few other scientists, including Albert Einstein , wrote to President Roosevelt in to warn him about the possibility of creating nuclear weapons.
The President authorized an advisory committee to begin developing atomic bombs for the US. By , Fermi, working as part of the committee, was able to create the first man-made fission chain reaction in Chicago.
It was at this point that the Manhattan project swung into full development. The team pursued the development of two types of bombs, one using uranium as a core, and one plutonium. The project was highly secretive, and entire covert cities were built to support the project. One facility, in Oak Ridge, Tennessee, used nuclear reactions to create plutonium to be used for producing enriched uranium. Another facility in Washington used nuclear reactions to produce plutonium.
The now-famous secret site in Los Alamos, New Mexico , was used by hundreds of scientists for the research and construction of nuclear weapons. The end of WWII, in , saw the first use of nuclear weapons on people. This was also the moment when the majority of the world's population, realized just how destructive this technology could be. It was before the first nuclear reactor which produced electricity was completed.
Peierls then stated that there was now no doubt that the whole scheme for a bomb was feasible provided highly enriched U could be obtained. The predicted critical size for a sphere of U metal was about 8kg, which might be reduced by use of an appropriate material for reflecting neutrons. However, direct measurements on U were still necessary and the British pushed for urgent production of a few micrograms.
The first report concluded that a bomb was feasible and that one containing some 12 kg of active material would be equivalent to 1, tons of TNT and would release large quantities of radioactive substances which would make places near the explosion site dangerous to humans for a long period.
Suggesting that the Germans could also be working on the bomb, it recommended that the work should be continued with high priority in cooperation with the Americans, even though they seemed to be concentrating on the future use of uranium for power and naval propulsion. The second MAUD Report concluded that the controlled fission of uranium could be used to provide energy in the form of heat for use in machines, as well as providing large quantities of radioisotopes which could be used as substitutes for radium.
It referred to the use of heavy water and possibly graphite as moderators for the fast neutrons, and that even ordinary water could be used if the uranium was enriched in the U isotope. It concluded that the 'uranium boiler' had considerable promise for future peaceful uses but that it was not worth considering during the present war. The Committee recommended that Halban and Kowarski should move to the USA where there were plans to make heavy water on a large scale.
The possibility that the new element plutonium might be more suitable than U was mentioned, so that the work in this area by Bretscher and Feather should be continued in Britain.
The two reports led to a complete reorganisation of work on the bomb and the 'boiler'. It was claimed that the work of the committee had put the British in the lead and that "in its fifteen months' existence it had proved itself one of the most effective scientific committees that ever existed". The basic decision that the bomb project would be pursued urgently was taken by the Prime Minister, Winston Churchill, with the agreement of the Chiefs of Staff.
The reports also led to high level reviews in the USA, particularly by a Committee of the National Academy of Sciences, initially concentrating on the nuclear power aspect. Little emphasis was given to the bomb concept until 7 December , when the Japanese attacked Pearl Harbour and the Americans entered the war directly.
The huge resources of the USA were then applied without reservation to developing atomic bombs. The Americans increased their effort rapidly and soon outstripped the British.
Research continued in each country with some exchange of information. Several of the key British scientists visited the USA early in and were given full access to all of the information available. The Americans were pursuing three enrichment processes in parallel: Professor Lawrence was studying electromagnetic separation at Berkeley University of California , E.
Murphree of Standard Oil was studying the centrifuge method developed by Professor Beams, and Professor Urey was coordinating the gaseous diffusion work at Columbia University. Responsibility for building a reactor to produce fissile plutonium was given to Arthur Compton at the University of Chicago. The British were only examining gaseous diffusion. In June the US Army took over process development, engineering design, procurement of materials and site selection for pilot plants for four methods of making fissionable material because none of the four had been shown to be clearly superior at that point as well as the production of heavy water.
With this change, information flow to Britain dried up. This was a major setback to the British and the Canadians who had been collaborating on heavy water production and on several aspects of the research program. Thereafter, Churchill sought information on the cost of building a diffusion plant, a heavy water plant and an atomic reactor in Britain. After many months of negotiations an agreement was finally signed by Mr Churchill and President Roosevelt in Quebec in August , according to which the British handed over all of their reports to the Americans and in return received copies of General Groves' progress reports to the President.
Construction of production plants for electromagnetic separation in calutrons and gaseous diffusion was well under way. An experimental graphite pile constructed by Fermi had operated at the University of Chicago in December — the first controlled nuclear chain reaction.
A full-scale production reactor for plutonium was being constructed at Argonne, with further ones at Oak Ridge and then Hanford, plus a reprocessing plant to extract the plutonium.
Four plants for heavy water production were being built, one in Canada and three in the USA. The outcome of the huge effort, with assistance from the British teams, was that sufficient Pu and highly enriched U from calutrons and diffusion at Oak Ridge was produced by mid The uranium mostly originated from the Belgian Congo. The first atomic device tested successfully at Alamagordo in New Mexico on 16 July It used plutonium made in a nuclear pile.
The teams did not consider that it was necessary to test a simpler U device. The first atomic bomb, which contained U, was dropped on Hiroshima on 6 August The second bomb, containing Pu, was dropped on Nagasaki on 9 August. On 10 August the Japanese Government surrendered. Initially Stalin was not enthusiastic about diverting resources to develop an atomic bomb, until intelligence reports suggested that such research was under way in Germany, Britain and the USA.
Consultations with Academicians Ioffe, Kapitsa, Khlopin and Vernadsky convinced him that a bomb could be developed relatively quickly and he initiated a modest research program in Igor Kurchatov, then relatively young and unknown, was chosen to head it and in he became Director of Laboratory No. Overall responsibility for the bomb program rested with Security Chief Lavrenti Beria and its administration was undertaken by the First Main Directorate later called the Ministry of Medium Machine Building.
Research had three main aims: to achieve a controlled chain reaction; to investigate methods of isotope separation; and to look at designs for both enriched uranium and plutonium bombs. Attempts were made to initiate a chain reaction using two different types of atomic pile: one with graphite as a moderator and the other with heavy water.
Three possible methods of isotope separation were studied: counter-current thermal diffusion, gaseous diffusion and electromagnetic separation. After the defeat of Nazi Germany in May , German scientists were "recruited" to the bomb program to work in particular on isotope separation to produce enriched uranium. This included research into gas centrifuge technology in addition to the three other enrichment technologies.
The test of the first US atomic bomb in July had little impact on the Soviet effort, but by this time, Kurchatov was making good progress towards both a uranium and a plutonium bomb.
He had begun to design an industrial scale reactor for the production of plutonium, while those scientists working on uranium isotope separation were making advances with the gaseous diffusion method. It was the bombing of Hiroshima and Nagasaki the following month which gave the program a high profile and construction began in November of a new city in the Urals which would house the first plutonium production reactors -- Chelyabinsk Later known as Chelyabinsk or the Mayak production association.
This was the first of ten secret nuclear cities to be built in the Soviet Union. The first of five reactors at Chelyabinsk came on line in This town also housed a processing plant for extracting plutonium from irradiated uranium. As for uranium enrichment technology, it was decided in late to begin construction of the first gaseous diffusion plant at Verkh-Neyvinsk later the closed city of Sverdlovsk , some 50 kilometres from Yekaterinburg formerly Sverdlovsk in the Urals.
Support was provided by a group of German scientists working at the Sukhumi Physical Technical Institute. In April design work on the bomb was shifted to Design Bureau — a new centre at Sarova some kilometres from Moscow subsequently the closed city of Arzamas More specialists were brought in to the program including metallurgist Yefim Slavsky who was given the immediate task of producing the very pure graphite Kurchatov needed for his plutonium production pile constructed at Laboratory No.
The pile was operated for the first time in December Support was also given by Laboratory No. Work at Arzamas was influenced by foreign intelligence gathering and the first device was based closely on the Nagasaki bomb a plutonium device.
In August a test site was established near Semipalatinsk in Kazakhstan and was ready for the detonation two years later of the first bomb, RSD Even before this was tested in August , another group of scientists led by Igor Tamm and including Andrei Sakharov had begun work on a hydrogen bomb. By the end of World War II, the project predicted and described in detail only five and a half years before in the Frisch-Peierls Memorandum had been brought to partial fruition, and attention could turn to the peaceful and directly beneficial application of nuclear energy.
Post-war, weapons development continued on both sides of the "iron curtain", but a new focus was on harnessing the great atomic power, now dramatically if tragically demonstrated, for making steam and electricity.
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