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Rabu, 20 Februari 2019

Nuclear Technology: History, Fission & Fusion Reactions and its uses


Nuclear Technology: History, Fission & Fusion Reactions and its uses

 
Nuclear technology is a technology that involves the reaction of an atomic nucleus (nucleus = nuclei). Nuclear technology can be found in various applications, from simple ones such as smoke detectors to something as large as a nuclear reactor.

History of Nuclear Technology
Events in everyday life, natural phenomena, are rarely related to nuclear reactions. Almost all of them involve gravity and electromagnetism. Both are part of the four basic styles of nature, and are not the strongest. But the other two, weak nuclear forces and strong nuclear forces are forces that work in short ranges and do not work outside the atomic nucleus. The nucleus consists of a positive charge which will actually stay away from one another if there is no force holding it back.

Henri Becquerel in 1896 examined the phenomenon of phosphorescence in uranium salts when he discovered something which was finally called radioactivity. He, Pierre Curie, and Marie Curie began researching this phenomenon. In the process, they isolate the highly radioactive element radium. They found that radioactive materials produce intense waves, which they call alpha, beta, and gamma. Some types of radiation that they find can penetrate various materials and all of them can cause damage. All radioactivity researchers at that time suffered radiation burns, which were similar to sunburns, and only a few thought about that.

A new phenomenon regarding radioactivity is known since the existence of patents in the medical world involving radioactivity. Slowly, it is known that the radiation produced by radioactive decay is ionized radiation. Many radioactive researchers have died of cancer in the past as a result of their exposure to radioactivity. Most medical patents regarding radioactivity have been removed, but other applications involving radioactive material still exist, such as the use of radium salt to make sparkling objects.

Since atoms become more understood, the nature of radioactivity becomes clearer. Some large atomic nuclei tend to be unstable, so that decay occurs until a certain interval before reaching stability. The three forms of radiation found by Becquerel and Curie have also been understood; alpha decay occurs when the nucleus of an atom releases alpha particles, namely two protons and two neutrons, equivalent to the helium atomic nucleus; Beta decay occurs when the release of beta particles, namely high-energy electrons; Gamma decay releases gamma rays, which are not the same as alpha and beta radiation, but are electromagnetic radiation at very high frequencies and energies. All three types of radiation occur naturally, and gamma ray radiation is the most dangerous and difficult to resist.

Following is the timeline of nuclear technology from 1896 to 1962

1896

  
French physicist Henri Becquerel discovered the symptoms of radioactivity when his photographic plates were blurred by rays of uranium.

1898


  
Pierre and Marie Curie started the project which led to the discovery of a new element - radium.

1902

 
British physicist Ernest Rutherford and chemist Frederick Soddy explain radioactive decay that converts elements such as radium into other elements while producing energy.

1905

Albert Einstein, employee of the patent in Bern, shows the equality of mass and energy in the equation E = mc, as part of the Kenisbian Theory of special relativity. This equation predicts that enormous energy is locked in matter

1910

Soddy proposed the existence of an isotope - an elemental form that has the same chemical properties but different atomic weights.

1911
Rutherford, using alpha particles, investigates the inside of an atom and finds its heavy core.

1913
Francis Aston, an English chemist, convincingly showed the presence of isotopes. Danish physicist Niels Bohr proposed his theory based on what Rutherford had discovered and the quantum theory of German physicist Max Planck.

1919
Rutherford shows changes in nitrogen into oxygen and hydrogen after being hit by alpha particles. This is the first nuclear reaction observed by humans.

1928
In the first steps towards a basic understanding of nuclear weapons, Americans Edward Condon and Ronald Gurney and George Gamow who were born in Russia, in their own investigation, explained how alpha particles are emitted from the nucleus.

1931
Deuterium, the heavy isotope of hydrogen which is then used in the first hydrogen bomb (H-bomb), was discovered by an American chemist, Harold Urey.

1932
British physicist John Cockroft and Irish physicist Ernest Walton worked together to convert lithium into a helium nucleus, using accelerated protons with simple "atomic breakers". This is the first experimental proof of Einstein's formula E = mc2.
Neutrons, the atomic constituents that turned out to be the key to the division of the nucleus, were discovered by British physicist James Chadwick.

1933

Irene and Frederic Joliot-Curie, French physicists, showed that some atoms are stable, undergo nuclear reactions when hit by alpha particles and turn into short-lived unstable isotopes. This is the radioactivity of the first artificial age.

1938

Hans Bethe in the United States theorizes that solar energy comes from fusion reactions, a process that combines two light nuclei and releases a large amount of energy. The reaction term that now produces an H-bomb explosion.

1939
Otto Hahn and Fritz Strassmann in Berlin fired on uranium with neutrons and found lighter barium elements as a result of that reaction, but could not explain the experiment with the emergence of the barium. The German escape Otto Frisch and Lise Metner describe the Hahn and Strassmann experiments as fission - the division of a heavy nucleus into lighter nuclei, for example the barium nucleus, by releasing a lot of energy.

Frederic Jolit-Curie shows that the fission of one uranium atom by one neutron produces two or three free neutrons. This suggests the possibility of a chain reaction; in this reaction the new neutron continues and expands the reaction initiated by the initial neutron collision. Bohr predicted that uranium-235 would divide when shot by neutrons, but U-235 was very rare.

Albert Einstein in the United States at the Advanced Review Institute warned President Roosevelt of the military dangers of atomic energy.

1940
Chemists at the University of California led by Glenn Seaborg and Edwin McMillan found plutonium, the radioactive firing of U-238, and a good substitute for rare U-235. The gas diffusion method for separating uranium isotopes was developed at the University of Colombia.

1942
Under the direction of Enrico Fermi the first atomic reactor was built, and on December 2, 1942, at 15.52, the first chain reaction took place in a project initiated and coordinated by Arthur H. Compton. An U.S. military atomic program codenamed the Manhattan Project, formed under the leadership of Major General Leslie R.

Groves. At Oak Ridge, Tennessee, a mass spectrometer was used to produce pure U-235, under the direction of Ernest O. Lawrence. The construction of the atomic bomb laboratory began at Los Alamos, New Mexico, under the direction of J. Robert Oppenheimer.

1943

Reactors were built in Hanford, Washington, to produce plutonium.

1945

The first atomic bomb was launched in Alamogordo, New Mexico, Monday, July 16. The first atomic bomb destroyed Hiroshima, Friday, August 6. Nagasaki was the second target on August 9th.

1949

The Soviet Union detonated their first atomic bomb.

1950
President Harry S. Truman on January 31 announced that he had approved the Atomic Energy Commission to continue the development of the H-bomb.

1952
The first British atomic bomb was detonated on October 3 on Monte Bello Island off the coast of Australia. Explosion of U.S. H-bomb trials. The first occurred near the Eniwetok Atoll in the Pacific, on November 1.

1953
In August the Soviet Union detonated the 1954 H-bomb.

1954
  
USS Nautilus, the first atomic submarine was launched.

1956
 
The first reactor to produce electricity started working at Calder Hall, England.

1957
 
Shippingport reactor, the first atomic power plant in the U.S. began operating.

1959.
The first trial of a small atomic reactor - KiwiA - for rocket use occurred at the Nevada testing site.

1960
 
France detonates an atomic bomb in a trial in the Sahara.

1961
The Soviet Union tested the largest H-bomb (55 to 60 megatons) on the island of the Novaya Zemlya polar region. US. Started the Plow Eye Project, a series of large-scale nuclear explosion experiments for peaceful purposes such as the manufacture of canals.

1962

US. Blow up the H-bomb from Thor's rocket and create a man-made radiation zone. The inaugural journey of the U.S. Savannah nuclear ship, the first atomic-powered merchant ship.

Nuclear Reaction
Fisi Nuclear Reaction
Fission Nuclear Reaction is the process of dividing the nucleus into smaller atoms and is accompanied by the release of energy and neutrons. If these neutrons are captured by other unstable nuclei, eating the nucleus will divide as well, triggering a chain reaction. If the average number of neutrons released per atomic nucleus which carries fission to another atomic nucleus is symbolized by k, then a k value greater than 1 indicates that the fission reaction releases more neutrons than the amount absorbed, so that this reaction can be said can stand alone. The minimum mass of a fission material capable of carrying out a stand-alone chain fission is called critical mass.

When neutrons are captured by the right nucleus, fission will occur immediately, or the atomic nucleus will be in an unstable condition in a short time. When discovered during World War II, this triggered several countries to begin research programs about the possibility of making atomic bombs, a weapon that uses fission reactions to produce enormous energy, far exceeding chemical explosives (TNT, etc.). The Manhattan project, run by the United States with the help of Britain and Canada, developed fission weapons used against Japan in 1945. During the project, the first fission reactor was developed, although initially it was used only for the manufacture of weapons and not for generating electricity for the community.

However, if the neutrons used in the fission reaction can be controlled, for example with neutron absorbers, and these conditions still make the mass of nuclear material a critical status, then the fission reaction can be controlled. This is what underlies the working principle of nuclear reactors. Neutrons move at very high speeds, to control neutrons so they don't react with other nuclei, then neutrons must be slowed using neutron absorbers before they can be easily captured. At present, this method is commonly used to generate electricity.

Fusion Nuclear Reaction
If two atomic nuclei collide, there is a possibility of a fusion nuclear reaction. This process will release or absorb energy. If the atomic nucleus resulting from collisions is lighter than iron, generally fusion nuclear reactions will release energy, but if the atomic nucleus resulting from collisions is heavier than iron, then fusion nuclear reactions will generally absorb energy. The most common process of fusion nuclear reaction is in stars, fusion nuclear reaction energy that occurs in stars is produced by nuclear fusion of hydrogen and produces helium. From fusion nuclear reactions, stars also form light elements such as lithium and calcium through stellar nucleosynthesis.

This natural process of astrophysics is not an example of nuclear technology. Because of the high energy thrust of the atomic nucleus, fusion is difficult to do under controlled conditions (eg hydrogen bombs). Controlled fusion can be carried out in particle accelerators, which is a system of how synthetic elements are made. Technical and theoretical difficulties prevent the development of nuclear fusion technology for civilian purposes, although research on this technology throughout the world continues to this day.

Nuclear fusion theoretically began to be investigated during World War II, when the Manhattan Project researchers led by Edward Teller examined it as a method of making bombs. The project was abandoned after concluding that this required a fission reaction to activate the hydrogen bomb. This continued until 1952, when the first hydrogen bomb was detonated. It is called a hydrogen bomb because it utilizes a reaction between deuterium and tritium, an isotope of hydrogen. The fusion reaction produces more energy per unit mass of material than a fission reaction, but it is more difficult to make it react in chains.

Nuclear Use
Nuclear energy
Nuclear energy is a type of nuclear technology that involves the use of control of nuclear fission reactions to release energy, including propulsion, heat, and the generation of electrical energy. Nuclear energy is produced by controlled nuclear reactions that create heat which is then used to heat water, produce steam, and control steam turbines. This turbine is used to produce electrical energy and / or do mechanical work. See nuclear reactor technology. At present, nuclear energy is used to drive aircraft carriers, icebreakers and submarines, besides that there is a Floating Nuclear Power Plant (PLTN).
Medical application
Medical applications of nuclear technology are divided into diagnosis and radiation therapy, effective treatments for cancer patients. Imaging (X-rays and so on), use of technetium to be given to organic molecules, search for radioactive traces in the body before being excreted by the kidneys, and others.

Industrial application
In oil and gas exploration, the use of nuclear technology is useful to determine the nature of surrounding rocks such as porosity and lithography. This technology involves the use of neutrons or energy sources of gamma rays and radiation detectors planted in the rocks to be examined. In road construction, measuring humidity and density using nuclear is used to measure the density of soil, asphalt, and concrete. Usually used cesium-137 as a source of nuclear energy.

Commercial application
Ionization of americium-241 is used in smoke detectors by utilizing alpha radiation. Tritium is used with phosphorus in the rifle to increase the accuracy of night shooting. The "exit" sign uses the same technology.

Food and agricultural processing
Food irradiation is the process of exposing food by radiation ionization with the aim of destroying microorganisms, bacteria, viruses, or insects thought to be in food. The types of radiation used are gamma rays, X-rays, and electrons which are released by electron accelerators. Other applications are prevention of the process of germination, inhibiting fruit ripening, increasing yield of fruit flesh, and increasing rehydration. Broadly speaking, irradiation is the exposure of a material to radiation to obtain technical benefits. Such techniques are also used in medical devices, plastics, tubes for gas pipelines, channels for floor heating, sheets for food packaging, automotive parts, cables, tires, and even jewelry stones.

The main effect in food processing using radiation ionization is related to DNA damage, basic information on life. Microorganisms can no longer breed and continue their activities. Insects will not survive and become unable to develop. Plants are unable to continue the process of fruit ripening and aging. All of these effects benefit consumers and the food industry.

The advantage of food processing with radiation ionization is that the energy density per transition of the atom is very high and is able to divide the molecule and induce ionization (reflected in the name of the method) which cannot be done by ordinary heating. This is the reason for the beneficial effects, and at the same time, raises concerns. The treatment of solid food ingredients with ionizing radiation can create the same effect as pasteurizing liquid food ingredients such as milk. However, the use of the term cold pasteurization and irradiation is a different process, although it aims and gives the same results in some cases. Food irradiation is currently permitted in 40 countries and its volume is estimated to exceed 500,000 metric tons annually worldwide.



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