Nuclear. Technology. As technology that. Involves the nuclear, reactions. Of atomic, nuclei. Among. The notable nuclear. Technologies. Are nuclear, reactors. Nuclear medicine, and, nuclear, weapons it is. Also used, among, other things in, smoke, detectors. And gun sights. Topic. History. And scientific. Background. Topic. Discovery. The, vast majority of, common, natural, phenomena, on earth only, involve, gravity. And electromagnetism. And not nuclear, reactions. This. Is because, atomic, nuclei, are generally, kept apart because they contain, positive. Electrical. Charges, and therefore, repel, each other in. 1896. On Rebecca. L was investigating. Phosphorescence. In uranium, salts, when he discovered, a new phenomenon. Which came to be called radioactivity. He. Pierre, Curie and Marie Curie began. Investigating. The phenomenon, in the, process, they isolated, the element, radium, which is highly radioactive. They. Discovered, that radioactive. Materials. Produce, intense, penetrating. Rays of three distinct, sorts which they labeled alpha, beta and gamma, after the first three Greek letters. Some. Of these kinds, of radiation could, pass through ordinary matter, and all of them could be harmful in large amounts, all. Of, the early researchers. Received, various, radiation. Burns much like sunburn, and thought little of it, the. New phenomenon. Of radioactivity. Was, seized upon by the manufacturers. Of quack, medicine, has had the discoveries. Of electricity, and magnetism earlier. And a number of patent, medicines, and treatments, involving, radioactivity. Were, put forward. Gradually. It was realized, that the radiation. Produced, by radioactive decay, was. Ionizing. Radiation. And that even, quantities, too small to burn could pose a severe, long-term hazard. Many. Of the scientists. Working on radioactivity. Died of cancer as, a result of their exposure. Radioactive. Patent, medicines, mostly, disappeared. But other applications. Of radioactive. Materials. Persisted. Such as the use of radium, salts, to produce glowing. Dials, on meters as. The. Atom came to be better understood the. Nature of radioactivity. Became. Clearer. Some. Larger, atomic nuclei, are unstable, and so decay, release, matter or energy after. A random interval. The. Three, forms, of radiation, that Becker and the Curie's, discovered. Are also more, fully understood. Alpha. Decay as when a nucleus, releases. An alpha particle which, has two protons and, two neutrons, equivalent. To a helium, nucleus. Beta. Decay, as the release of a beta particle a high-energy, electron. Gamma. Decay releases. Gamma rays which, unlike alpha, and beta radiation are, not matter but, electromagnetic. Radiation. Of very high frequency. And therefore energy. This. Type of radiation is, the most dangerous, and most difficult to block all. Three, types of radiation occur, naturally in, certain elements. It has also become clear, that the ultimate source, of most terrestrial, energy as, nuclear, either through, radiation. From the Sun caused, by stellar thermonuclear. Reactions. Or by radioactive. Decay of uranium within. The earth the principal, source of geothermal, energy. Topic. Nuclear. Fission. In natural. Nuclear, radiation, the, byproducts. Are very small compared, to the nuclei, from which they originate. Nuclear. Fission, as the process, of splitting a nucleus, into, roughly equal, parts, and releasing. Energy and, neutrons, in the process, if, these. Neutrons, are captured, by another unstable. Nucleus, they can fission as well leading to a chain reaction. The. Average, number of neutrons, released per, nucleus, that go on deficient, another nucleus, as referred, to as K. Values. Of K larger, than 1 mean that the fission, reaction is, releasing, more neutrons, than it absorbs, and therefore, is referred, to as a self-sustaining. Chain reaction. A mass. Of fissile, material, large enough, and in a suitable, configuration. To induce a self-sustaining. Chain reaction. Is called a critical mass. When. A neutron, is captured, by a suitable, nucleus, fission, may occur immediately or, the nucleus, may persist, in an unstable, state for a short time if there. Are enough immediate, decays, to carry on the chain reaction, the mass is said to be prompt, critical and the energy, release, will grow rapidly and, uncontrollably. Usually. Leading to an explosion. When, discovered, on the eve of World War two. This insight, led multiple, countries to, begin programs. Investigating. The possibility, of constructing an atomic, bomb a weapon. Which utilized, fish, and reactions, to generate, far more energy, than could be created, with chemical, explosives. The. Manhattan, Project run, by the United, States with the help of the United Kingdom, and Canada developed. Multiple fish, and weapons, which were used against, Japan, in, 1945. At Hiroshima.
And Nagasaki. During. The project, the first fission, reactors, were developed, as well though they were primarily for, weapons, manufacture. And did not generate, electricity, in. 1951. The, first nuclear fission. Power plant, was the first to produce electricity. At, the experimental. Breeder reactor. Number one EBR. One in Arco, Idaho. Assuring. In the atomic. Age of more. Intensive. Human, energy, use however, if the mass is critical, only when the delayed neutrons, are included, then the reaction, can be controlled, for example, by the introduction. Or removal, of Neutron, absorbers. This. Is what allows nuclear. Reactors. To be built fast. Neutrons. Are not easily, captured, by nuclei. They must be slowed slow, neutrons, generally. By collision, with the nuclei, of a neutron, moderator before. They can be easily captured. Today. This type of fission, is commonly, used to generate electricity. Topic. Nuclear. Fusion. If nuclei. Are forced, to collide they, can undergo nuclear. Fusion. This. Process, may release, or absorb, energy, when. The resulting, nucleus, has lighter than that of iron energy. Is normally, released, when, the nucleus is, heavier than that of iron energy. Has generally. Absorbed. This. Process, of fusion occurs, in stars which, derive, their energy from, hydrogen and, helium, they. Form through, stellar nucleosynthesis. The. Light elements lithium. To calcium, as well as some of the heavy elements beyond, iron and nickel via, the s process. The. Remaining, abundance, of heavy elements from, nickel to uranium, and Beyond is due, to supernova. Nucleosynthesis, the. R process, of. Course. These natural, processes, of astrophysics, are, not examples, of nuclear, technology. Because. Of the very strong repulsion, of nuclei, fusion. Is difficult, to achieve in a controlled, fashion. Hydrogen. Bombs obtain, their enormous destructive. Power from, fusion but their energy cannot, be controlled. Controlled. Fusion. As achieved, in particle, accelerators. This is how many synthetic elements. Are produced a. Fuser. Can also produce, controlled. Fusion, and as a useful, neutron. Source. However. Both. Of these devices operate. At a net energy loss. Controlled. Viable, fusion, power has, proven elusive despite, the occasional hoax. Technical. And theoretical, difficulties. Have hindered the development, of working, civilian, fusion, technology, though research, continues. To this day around, the world.
Nuclear. Fusion, was initially pursued. Only in theoretical. Stages during, World War two when, scientists, on the manhattan, project led. By Edward, Teller, investigated. It as a method to build a bomb, the. Project, abandoned, fusion, after concluding that it would require a fission, reaction, to detonate. It took until. 1952. For the first full hydrogen. Bomb to be detonated so-called, because it used reactions. Between deuterium. And tritium. Fusion. Reactions. Are much more energetic, per unit mass of fuel, than fission, reactions, but starting, the fusion, chain reaction. Is much more difficult. Topic. Nuclear. Weapons. A nuclear. Weapon, as an explosive. Device that, derives, its destructive, force from nuclear, reactions, either fission. Or a combination, of fission, and fusion. Both. Reactions, release, vast quantities. Of energy from, relatively. Small amounts, of matter, even. Small, nuclear, devices, can, devastate a city, by blast fire, and radiation. Nuclear. Weapons, are considered, weapons, of mass destruction, and their use and control, has been a major aspect, of international policy. Since, their debut. The. Design, of a nuclear, weapon, is more complicated. Than it might seem. Such. A weapon, must hold one or more subcritical, fissile. Masses, stable, for deployment then induced, criticality, create. A critical mass for, detonation. It. Also is quite difficult to ensure that such a chain, reaction consumes. A significant. Fraction of the fuel before the device flies, apart, the. Procurement. Of the nuclear, fuel, is also more, difficult, than it might seem, since sufficiently. Unstable. Substances. For this process, do not currently occur, naturally on, earth in, suitable amounts. One. Isotope of uranium namely. Uranium-235. Is naturally. Occurring and sufficiently. Unstable. But it is always found, mixed with the more stable isotope. Uranium. 238. The, latter. Accounts, for more than 99%. Of the weight of natural, uranium. Therefore. Some method, of isotope, separation based. On the weight of three, neutrons, must, be performed, to enrich isolate. Uranium-235. Alternatively. The element, plutonium. Possesses. An isotope, that is sufficiently. Unstable. For this process, to be usable. Terrestrial. Plutonium. Does not currently occur, naturally in, sufficient, quantities. For such use so, it must be manufactured. In a nuclear, reactor. Ultimately. The, Manhattan, Project, manufactured. Nuclear, weapons, based on each of these elements, they. Detonated, the first nuclear, weapon in the test code named Trinity. Near. Alamogordo, New, Mexico on. July, 16, 1945. The. Test was conducted to ensure that the implosion, method. Of detonation. Would work which it did a, uranium. Bomb little. Boy was, dropped on the Japanese city, Hiroshima. On August 6. 1945. Followed. Three days later by the plutonium. Based fat man on Nagasaki. In the. Wake of unprecedented. Devastation and. Casualties. From a single, weapon the Japanese, government soon. Surrendered, ending, world war two. Since. These bombings no, nuclear, weapons have been deployed offensively. Nevertheless. They. Prompted, an arms race to, develop increasingly. Destructive. Bombs, to provide a nuclear deterrent. Just. Over four years later on August, 29. 1949. The, Soviet, Union, detonated. Its first fish, and weapon, the. United, Kingdom, followed, on October. 2nd, 1950. To France, On February 13. 1960. And China, component. To a nuclear, weapon. Approximately. Half of the deaths from Hiroshima. And Nagasaki died. Two to five years afterward. From radiation, exposure a. Radiological. Weapons, as the type of nuclear, weapon, designed, to distribute, hazardous, nuclear, material. In enemy areas. Such. A weapon would not have the explosive, capability of. Efficient, or fusion bomb but, would kill many people and contaminate. A large, area, a. Radiological. Weapon has never been deployed while. Considered, useless, by a conventional. Military such. A weapon raises, concerns, over nuclear terrorism.
There, Have been over 2,000. Nuclear, tests. Conducted since. 1945. In. 1963. All nuclear. And many non-nuclear. States signed. The limited, test ban treaty, pledging. To refrain, from testing. Nuclear weapons. In the atmosphere. Underwater, or in outer space. The. Treaty permitted, underground, nuclear testing. France. Continued. Atmospheric. Testing, until. 1974. While China continued. Up until 1980. The. Last underground. Test by the United, States was, in 1992. The Soviet, Union in 1990. The United Kingdom, in 1991. And both France, and China continued. Testing until. 1996. After. Signing, the comprehensive. Test-ban treaty in. 1996. Which had as of 2011, not. Entered, into force all of these states have pledged to discontinue, all, nuclear, testing. Non-signatories. India, and Pakistan. Last tested, nuclear weapons, in, 1998. Nuclear. Weapons, are the most destructive weapons. Known the archetypal. Weapons of mass destruction. Throughout. The Cold War the opposing, powers, had huge nuclear arsenals. Sufficient. To kill hundreds, of millions, of people. Generations. Of people grew, up under the shadow of nuclear, devastation, portrayed. In films, such as dr., Strangelove and, the atomic cafe. However. The tremendous, energy, release, in the detonation, of a nuclear weapon. Also, suggested. The possibility. Of a new energy source. Topic. Civilian. Uses. Topic. Nuclear. Power. Nuclear. Power is a type of nuclear. Technology, involving. The controlled, use of nuclear, fission to release energy for, work including, propulsion. Heat and the generation. Of electricity. Nuclear. Energy is, produced by, a controlled, nuclear, chain reaction. Which creates, heat and which. Is used to boil water produce. Steam and drive a steam, turbine. The. Turbine, is used to generate electricity, and/or, to do mechanical, work. Currently. Nuclear. Power provides. Approximately, fifteen. Point, seven percent, of the world's, electricity in. 2004. And is used to propel, aircraft, carriers, icebreakers. And submarines, so far economics. And fears in some ports have prevented, the use of nuclear power in transport. Ships, all. Nuclear. Power plants, use fission, no. Man-made, fusion, reaction, has resulted in a viable source of electricity. Topic. Medical. Applications. The, medical, applications. Of nuclear technology, are. Divided, into diagnostics. And radiation, treatment. Imaging. The largest, use of ionizing. Radiation. In medicine, is in medical, radiography to, make images of the inside of the human body using, x-rays. This. Is the largest artificial. Source, of radiation, exposure for. Humans. Medical. And dental x-ray. Imagers, use of cobalt-60. Or other x-ray, sources, a, number. Of radio pharmaceuticals. Are used sometimes, attached. To organic, molecules, to act as radioactive, tracers. Or contrast, agents, in the human body. Positron. Emitting, nucleotides. Are used for high resolution short. Timespan, imaging. In applications. Known as positron. Emission, tomography. Radiation. Is also used to treat diseases, in radiation, therapy. Topic. Industrial. Applications. Since. Some ionizing. Radiation. Can penetrate, matter, they are used for a variety of, measuring. Methods. X-rays. And gamma-rays are, used in industrial radiography. To, make images of the inside of solid, products, as a means, of non-destructive. Testing, and inspection. The. Piece to be radiographed. Is placed between the source and a photographic. Film in a cassette. After. A certain, exposure, time, the film is developed and it shows any internal. Defects, of the material. Gauges. Gauges. Use the exponential, absorption. Law of gamma rays. Level. Indicators. Source, and detector are, placed at opposite, sides of a container, indicating. The presence or, absence of, material. In the horizontal radiation, path. Beta. Or gamma sources. Are used depending, on the thickness and, the density, of the material to be measured, the. Method, is used for containers, of liquids, or of grainy substances.
Thickness. Gauges if the material, is of constant, density the, signal, measured, by the radiation. Detector, depends, on the thickness of the material. This. Is useful for continuous. Production, like of paper rubber, etc. Electrostatic. Control, to avoid the build-up of static electricity. In, production, of paper plastics. Synthetic, textiles, etc. A ribbon, shaped source of the alpha emitter. 241. M can be placed close, to the material at, the end of the production line. The. Source ionizes. The air to, remove electric. Charges, on the material. Radioactive. Tracers, since, radioactive. Isotopes. Behave, chemically. Mostly, like the inactive, element, the behavior, of a certain, chemical substance. Can be followed, by tracing the radioactivity. Examples. Gamma tracer, to a gas or liquid in, a closed system makes, it possible to, find a hole in a tube. Adding a tracer, to the surface, of the component of a motor makes it possible to measure wear by measuring, the activity of the lubricating, oil oil and, gas exploration, nuclear. Well logging, is used to help predict, the commercial, viability of, new or existing wells. The. Technology. Involves. The use of a neutron, or gamma-ray, source and a radiation, detector, which are lowered into bore holes to determine, the properties, of the surrounding, rock such, as porosity, and, lithography. One. Road. Construction, nuclear. Moisture. Density gauges. Are used to, determine the density of soils, asphalt. And concrete. Typically. A. Caesium-137, source has used. Topic. Commercial. Applications. Radio. Luminescence. Tritium. Illumination. Tritium, is used with phosphor, in rifle, sights to increase night time firing, accuracy. Some. Runway markers. And building, exit, signs use, the same technology. To remain, illuminated. During blackouts. Beta. Voltaics. Smoke. Detector, an ionization, smoke. Detector, includes, a tiny mass of radioactive. Americium-241. Which, is a source of alpha, radiation. To. Ionization, chambers. Are placed next to each other both. Contain, a small, source of, 241. M that gives rise to a, small, constant, current, one. Is closed, and serves for comparison. The other is open, to ambient air it has a gridded, electrode. When. Smoke enters, the open chamber the current, is disrupted. As the smoke particles, attached, to the charged ions, and restore, them to a neutral, electrical. State this. Reduces. The current, in the open chamber when. The current drops below a certain threshold the. Alarm is triggered. Topic. Food, processing. And agriculture. In biology. And. Agriculture. Radiation. Is used to induce mutations to. Produce new, or improved species. Another. Use in insect, control as, the sterile, insect, technique, where, male insects, are sterilized, by radiation, and released, so they have no offspring to reduce the population. In industrial, and, food applications. Radiation. Is used for sterilization. Of tools and equipment an. Advantage. Is that the object may be sealed, in plastic before. Sterilization. An. Emerging. Use in food production, as the sterilization.
Of Food using, food irradiation. Food. Irradiation as. The process, of exposing. Food to ionizing, radiation. In order to destroy. Microorganisms. Bacteria. Viruses. Or insects, that might be present in the food, the. Radiation. Sources used, include. Radioisotope. Gamma-ray. Sources, x-ray, generators. And electron, accelerators. Further. Applications. Include, sprout, inhibition. Delay, of ripening, increase. Of juice yield an improvement, of rehydration. Irradiation. Is, a more general, term of, deliberate, exposure, of materials. To radiation, to achieve a technical. Goal in this context. Ionizing. Radiation. Is implied, as, such. It is also used on non-food, items, such, as medical, hardware, plastics. Tubes, for gas pipelines. Hoses. For floor heating shrink, foils, for food packaging, automobile. Parts wires, and cables, isolation. Tires, and even gemstones. Compared. To the amount of food irradiated. The volume, of those everyday, applications is. Huge, but not noticed, by the consumer. The genuine, effect of processing. Food by ionizing. Radiation. Relates, to damages, to the DNA, the basic, genetic, information for, life. Microorganisms. Can no longer proliferate. And continue, their malignant, or pathogenic, activities. Spoilage. Causing, microorganisms. Cannot. Continue, their activities. Insects. Do not survive, or become, incapable, of procreation. Plants. Cannot, continue, the natural, ripening or, aging, process, all, these effects, are beneficial. To the consumer. And the food industry likewise. The amount of energy imparted, for, effective, food irradiation is. Low compared, to cooking, the same even, at a typical, dose of 10 kilo Gray's most, food which as with regard to warming, physically. Equivalent to, water would, warm by only about 2.5. Degrees Celsius. Four, point five degrees, Fahrenheit. The. Specialty. Of processing. Food by ionizing, radiation. As the fact that the energy density per, atomic, transition. Is very high, it can cleave molecules. And induce ionization. Hence the name which cannot, be achieved, by mere heating, this. Is the reason for new beneficial. Effects, however at the same time, for new concerns. The. Treatment, of solid, food by ionizing, radiation. Can provide, an effect similar to heat pasteurization. Of liquids, such, as milk. However. The, use of the term cold. Pasteurization. To describe, irradiated. Foods, as controversial. Because. Pasteurization. And irradiation are, fundamentally. Different processes. Although the intended, end results, can in some cases be, similar. Detractors. Of food irradiation have. Concerns, about the health hazards of, induced, radioactivity. Also. A report, for the American, Council, on science and health entitled. Irradiated. Foods. States. The. Types of radiation, sources, approved, for the treatment of foods, have, specific. Energy, levels, well below that which, would cause any element. In food to become radioactive. Food. Undergoing. Irradiation. Does, not become, any more, radioactive. Than luggage, passing. Through an airport x-ray. Scanner, or teeth that have been x-rayed. Food. Irradiation is. Currently, permitted, by over 40 countries and volumes, are estimated. To exceed, 500. Thousand, metric tons four, hundred ninety thousand, long tons. 550. Thousand, short tons annually, worldwide. Food. Irradiation is. Essentially. A non nuclear, technology. It relies, on the use of ionizing. Radiation. Which may be generated. By accelerators. For electrons, and conversion. Into bremsstrahlung but, which may use also gamma, rays from nuclear, decay. There. Is a worldwide, industry. For processing. By ionizing, radiation. The majority, by number, and by processing. Power using, accelerators. Food. Irradiation is. Only a niche application. Compared, to medical, supplies, plastic.
Materials. Raw materials. Gemstones. Cables. And wires etc. Topic. Accidents. Nuclear. Accidents. Because of the powerful, forces involved, are often, very dangerous. Historically. The, first incidents. Involved, fatal, radiation. Exposure, Marie. Curie died, from a plastic anemia, which, resulted, from her high levels, of exposure, to. Scientists. An American. And Canadian, respectively. Harry daghlian, and Louis Slotin died, after, miss handling, the same plutonium. Mass. Unlike. Conventional weapons. The intense, light heat an explosive. Force is not the only deadly component. To a nuclear, weapon. Approximately. Half of the deaths from Hiroshima. And Nagasaki died, two to five years afterward. From radiation, exposure. Civilian. Nuclear and Radiological. Accidents. Primarily, involved, nuclear power plants. Most. Common, are nuclear, leaks that expose, workers, to hazardous, material. A nuclear. Meltdown refers. To the more serious hazard. Of releasing, nuclear, material. Into the surrounding. Environment. The. Most significant. Meltdowns, occurred, at Three Mile Island in. Pennsylvania. And Chernobyl, in the Soviet, Ukraine. The. Earthquake, and tsunami on. March 11. 2011, caused. Serious, damage to three nuclear, reactors. And a spent fuel storage pond, at the Fukushima. Daiichi nuclear power. Plant in, Japan. Military. Reactors. That experienced. Similar accidents. Were Windscale, in the United, Kingdom, in sl1. In the United, States. Military. Accidents, usually, involve, the loss or unexpected. Detonation. Of nuclear weapons. The. Castle, Bravo test, in. 1954. Produced, a larger, yield than expected. Which contaminated. Nearby, islands, a Japanese. Fishing boat with one fatality, and raised, concerns, about contaminated. Fish in Japan, in the. 1950s. Through. 1970s. Several, nuclear, bombs. Were lost from submarines. And aircraft some, of which have never been recovered, the. Last 20, years have, seen a marked decline in such, accidents. Topic. See, also. Atomic. Age. Lists. Of nuclear, disasters. And radioactive. Incidents. Nuclear. Power debate. Outline. Of nuclear, technology.
2019-01-18