Nuclear technology is technology that involves the reactions of atomic nuclei. A smoke detector is a device that detects Smoke and issues an Alarm. In Nuclear physics, a nuclear reaction is the process in which two nuclei or nuclear particles collide to produce products different from the initial particles The nucleus of an Atom is the very dense region consisting of Nucleons ( Protons and Neutrons, at the center of an atom It has found applications from smoke detectors to nuclear reactors, and from gun sights to nuclear weapons. A smoke detector is a device that detects Smoke and issues an Alarm. This article is a subarticle of Nuclear power. A nuclear reactor is a device in which Nuclear chain reactions are initiated controlled "Sights" redirects here For the rock band see The Sights. A nuclear weapon is an explosive device that derives its destructive force from Nuclear reactions either fission or a combination of fission and fusion. There is a great deal of public concern about its possible implications, and every application of nuclear technology is reviewed with care.
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History
Discovery
In 1896, Henri Becquerel was investigating phosphorescence in uranium salts when he discovered a new phenomenon which came to be called radioactivity. Antoine Henri Becquerel (15 December 1852 &ndash 25 August 1908 was a French Physicist, Nobel laureate, and one of the discoverers of Radioactivity Phosphorescence is a specific type of Photoluminescence related to fluorescence. Uranium (jʊˈreɪniəm is a silvery-gray Metallic Chemical element in the Radioactive decay is the process in which an unstable Atomic nucleus loses energy by emitting ionizing particles and Radiation. [1] He, Pierre Curie and Marie Curie began investigating the phenomenon. Pierre Curie (15 May 1859 &ndash 19 April 1906 was a French physicist, a pioneer in Crystallography, Magnetism, Piezoelectricity In the process they isolated the element radium, which is highly radioactive. Radium (ˈreɪdiəm is a radioactive Chemical element which has the symbol Ra and Atomic number 88 They discovered that radioactive materials produce intense, penetrating rays of several distinct sorts, which they called alpha rays, beta rays and gamma rays. Alpha particles (named after and denoted by the first letter in the Greek alphabet, α consist of two Protons and two Neutrons bound together into a Beta particles are high-energy high-speed Electrons or Positrons emitted by certain types of Radioactive nuclei such as Potassium -40 Gamma rays (denoted as &gamma) are a form of Electromagnetic radiation or light emission of frequencies produced by sub-atomic particle interactions Some of these kinds of radiation could pass through ordinary matter, and all of them could cause damage in large amounts - all the early researchers received various radiation burns, much like sunburn, and thought little of it. A radiation burn is damage to the Skin or other Biological tissue caused by exposure to radio frequency energy or Ionizing radiation. A sunburn is a burn to living tissue such as Skin produced by overexposure to Ultraviolet (UV radiation commonly from the Sun 's rays
The new phenomenon of radioactivity was seized upon by the manufacturers of quack medicine (as had the discoveries of electricity and magnetism, earlier), and any number of patent medicines and treatments involving radioactivity were put forward. In Physics, magnetism is one of the Phenomena by which Materials exert attractive or repulsive Forces on other Materials. Patent medicine is the somewhat misleading term given to various medical Compounds sold under a variety of names and labels though they were for the most part actually Gradually it came to be realized that the radiation produced by radioactive decay was ionizing radiation, and that quantities too small to burn presented a severe long-term hazard. Image talkNew_radiation_symbol_ISO_21482svg for details --> Ionizing radiation Many of the scientists working on radioactivity died of cancer as a result of their exposure. Cancer (medical term Malignant Neoplasm) is a class of Diseases in which a group of cells display uncontrolled 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 atomic nuclei are unstable, and can decay releasing energy (in the form of: gamma rays, high-energy photons); (alpha particles, a pair of protons and a pair of neutrons; and beta particles, high-energy electrons). History See also Atomic theory, Atomism The concept that matter is composed of discrete units and cannot be divided into arbitrarily tiny Gamma rays (denoted as &gamma) are a form of Electromagnetic radiation or light emission of frequencies produced by sub-atomic particle interactions In Physics, the photon is the Elementary particle responsible for electromagnetic phenomena Alpha particles (named after and denoted by the first letter in the Greek alphabet, α consist of two Protons and two Neutrons bound together into a The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. Beta particles are high-energy high-speed Electrons or Positrons emitted by certain types of Radioactive nuclei such as Potassium -40 The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J
Nuclear fission
Radioactivity is generally a slow and difficult process to control, and is unsuited to building a weapon. However, other nuclear reactions are possible. In particular, a sufficiently unstable nucleus can undergo nuclear fission, breaking into two smaller nuclei and releasing energy and some fast neutrons. Nuclear fission is the splitting of the nucleus of an atom into parts (lighter nuclei) often producing Free neutrons and other smaller nuclei which may The neutron temperature, also called the neutron energy, indicates a free neutron's Kinetic energy, usually given in Electron volts The term This neutron could, if captured by another nucleus, cause that nucleus to undergo fission as well. The process could then continue in a nuclear chain reaction. A chain reaction is a sequence of Reactions where a reactive product or by-product causes additional reactions to take place Such a chain reaction could release a vast amount of energy in a short amount of time. When discovered on the eve of World War II, it led multiple countries to begin programs investigating the possibility of constructing an atomic bomb—a weapon which utilized fission reactions to generate far more energy than could be created with chemical explosives. World War II, or the Second World War, (often abbreviated WWII) was a global military conflict which involved a majority of the world's nations, including A nuclear weapon is an explosive device that derives its destructive force from Nuclear reactions either fission or a combination of fission and fusion. The Manhattan Project, run by the United States with the help of the United Kingdom and Canada, developed multiple fission weapons which were used against Japan in 1945. The World War II Manhattan Project developed the first Nuclear weapon (atomic bomb During the project, the first fission reactors were developed as well, though they were primarily for weapons manufacture and did not generate power.
Nuclear fusion
Nuclear fusion technology was initially pursued only in theoretical stages during World War II, when scientists on the Manhattan Project (led by Edward Teller) investigated the possibility of using the great power of a fission reaction to ignite fusion reactions. Timeline of significant events in the study and use of Nuclear fusion: 1929 - Atkinson and Houtermans used the measured masses Edward Teller (original Hungarian name Teller Ede) (January 15 1908 &ndash September 9 2003 was a Hungarian -American theoretical Physicist It took until 1952 for the first full detonation of a hydrogen bomb to take place, so-called because it utilized reactions between deuterium and tritium, isotopes of hydrogen. The Teller–Ulam design is a Nuclear weapon design which is used in Megaton -range Thermonuclear weapons and is more colloquially referred to as "the Deuterium, also called heavy hydrogen, is a Stable isotope of Hydrogen with a Natural abundance in the Oceans of Earth Tritium (ˈtɹɪtiəm symbol or, also known as Hydrogen-3) is a radioactive Isotope of Hydrogen. Hydrogen (ˈhaɪdrədʒən is the Chemical element with Atomic number 1 Fusion reactions are much more energetic per unit mass of fusion material, but it is much more difficult to ignite a chain reaction than is fission.
Research into the possibilities of using nuclear fusion for civilian power generation was begun during the 1940s as well. Technical and theoretical difficulties have hindered the development of working civilian fusion technology, though research continues to this day around the world.
Nuclear Weapons
The design of a nuclear weapon is more complicated than it might seem; it is quite difficult to ensure that such a chain reaction consumes a significant fraction of the fuel before the device flies apart. Nuclear weapon designs are physical chemical and engineering arrangements that cause the physics package of a nuclear weapon to detonate The construction of a nuclear weapon is also more difficult than it might seem, as no naturally occurring substance is sufficiently unstable for this process to occur. 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. Isotopes (Greek isos = "equal" tópos = "site place" are any of the different types of atoms ( Nuclides Thus a complicated and difficult process of isotope separation must be performed to obtain uranium-235. Isotope separation is the process of concentrating specific Isotopes of a Chemical element by removing other isotopes for example separating Natural uranium Alternatively, the element plutonium possesses an isotope that is sufficiently unstable for this process to be usable. Plutonium does not occur naturally, so it must be manufactured in a nuclear reactor. This article is a subarticle of Nuclear power. A nuclear reactor is a device in which Nuclear chain reactions are initiated controlled Ultimately, the Manhattan Project manufactured nuclear weapons based on each of these. The World War II Manhattan Project developed the first Nuclear weapon (atomic bomb
The first atomic bomb was detonated in a test code-named "Trinity", near Alamogordo on July 16, 1945. Trinity was the first test of technology for a Nuclear weapon. Alamogordo is a city in Otero County, New Mexico, United States of America. After much debate on the morality of using such a horrifying weapon, two bombs were dropped on the Japanese cities Hiroshima and Nagasaki, and the Japanese surrender followed shortly. The Japanese city of ( is the capital of Hiroshima Prefecture, and the largest city in the Chūgoku region of western Honshū, the largest of Japan 's ( is the Capital and the largest city of Nagasaki Prefecture in Japan.
Several nations began nuclear weapons programs, developing ever more destructive bombs in an arms race to obtain what many called a nuclear deterrent. The term arms race, in its original usage describes a competition between two or more parties for real or apparent military supremacy A nuclear deterrent is the phrase used to refer to a country's nuclear weapons arsenal when considered in the context of Deterrence theory. 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. Cold War is the state of conflict tension and competition that existed between the United States and the Soviet Union (USSR and their respective allies from the Generations of people grew up under the shadow of nuclear devastation.
However, the tremendous energy release in the detonation of a nuclear weapon also suggested the possibility of a new energy source.
Nuclear Power
Commercial nuclear power began in the early 1950s in the US, UK, and Soviet Union. Nuclear power is any Nuclear technology designed to extract usable Energy from atomic nuclei via controlled Nuclear reactions The United States of America —commonly referred to as the The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located The Union of Soviet Socialist Republics (USSR was a constitutionally Socialist state that existed in Eurasia from 1922 to 1991 The first commercial reactors were heavily based on either research reactors or military reactors. The first commercial nuclear reactor to go online in the US was the Shippingport Atomic Power Station in Western Pennsylvania. The Shippingport Atomic Power Station, "the world’s first full-scale atomic electric power plant devoted exclusively to peacetime uses" was located near the present-day Western Pennsylvania consists of the western third of the state of Pennsylvania in the United States.
Some countries have banned all forms of nuclear power.
Types of nuclear reaction
Most natural nuclear reactions fall under the heading of radioactive decay, where a nucleus is unstable and decays after a random interval. Radioactive decay is the process in which an unstable Atomic nucleus loses energy by emitting ionizing particles and Radiation. The most common processes by which this can occur are alpha decay, beta decay, and gamma decay. Alpha decay is a type of radioactive decay in which an Atomic nucleus emits an Alpha particle (two protons and two neutrons bound together into a particle In Nuclear physics, beta decay is a type of Radioactive decay in which a Beta particle (an Electron or a Positron) is emitted Gamma rays (denoted as &gamma) are a form of Electromagnetic radiation or light emission of frequencies produced by sub-atomic particle interactions Under suitable circumstances, a large unstable nucleus can break into two smaller nuclei, undergoing nuclear fission. Nuclear fission is the splitting of the nucleus of an atom into parts (lighter nuclei) often producing Free neutrons and other smaller nuclei which may
If these neutrons are captured by a suitable nucleus, they can trigger fission as well, leading to a chain reaction. A chain reaction is a sequence of Reactions where a reactive product or by-product causes additional reactions to take place A mass of radioactive material large enough (and in a suitable configuration) is called a critical mass. A critical mass is the smallest amount of Fissile material needed for a sustained Nuclear chain reaction. 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. In Nuclear engineering, an assembly is prompt critical if for each Nuclear fission event one or more of the immediate or Prompt neutrons released causes However, if the mass is critical only when the delayed neutrons are included, the reaction can be controlled, for example by the introduction or removal of neutron absorbers. Neutron absorbers are Isotopes of certain elements that absorb Free neutrons creating heavier isotopes of the same element This is what allows nuclear reactors to be built. This article is a subarticle of Nuclear power. A nuclear reactor is a device in which Nuclear chain reactions are initiated controlled 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. The neutron temperature, also called the neutron energy, indicates a free neutron's Kinetic energy, usually given in Electron volts The term In Nuclear engineering, a neutron moderator is a medium which reduces the velocity of Fast neutrons thereby turning them into Thermal neutrons capable
If nuclei are forced to collide, they can undergo nuclear fusion. In Physics and Nuclear chemistry, nuclear fusion is the process by which multiple- like charged atomic nuclei join together to form a heavier nucleus This process may release or absorb energy. When the resulting nucleus is lighter than that of iron, energy is normally released; when the nucleus is heavier than that of iron, energy is generally absorbed. Iron (ˈаɪɚn is a Chemical element with the symbol Fe (ferrum and Atomic number 26 This process of fusion occurs in stars, and results in the formation, in stellar nucleosynthesis, of the light elements, from lithium to calcium, as well as some formation of the heavy elements, beyond Iron and Nickel, which cannot be created by nuclear fusion, via neutron capture - the S-process. Stellar nucleosynthesis is the collective term for the nuclear reactions taking place in Stars to build the nuclei of the heavier elements. The S-process or slow-neutron -capture-process is a Nucleosynthesis process that occurs at relatively low neutron density and intermediate temperature conditions in The remaining abundance of heavy elements - from Nickel to Uranium and beyond - is due to supernova nucleosynthesis, the R-process. Supernova nucleosynthesis is the production of new Chemical elements inside Supernovae It occurs primarily due to explosive Nucleosynthesis during explosive The r-process is a Nucleosynthesis process occurring in core-collapse Supernovae (see also Supernova nucleosynthesis) responsible for the creation of approximately 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 obtaining controlled fusion power has so far proved elusive. The Teller–Ulam design is a Nuclear weapon design which is used in Megaton -range Thermonuclear weapons and is more colloquially referred to as "the Fusion power is power generated by Nuclear fusion reactions In this kind of reaction two light atomic nuclei fuse Controlled fusion can be achieved in particle accelerators; this is how many synthetic elements were produced. In chemistry the Chemical elements labeled as synthetic are too unstable to be found naturally on Earth. The Farnsworth-Hirsch Fusor is a device which can produce controlled fusion (and which can be built as a high-school science project), albeit at a net energy loss. The Farnsworth–Hirsch Fusor, or simply fusor, is an apparatus designed by Philo T It is sold commercially as a neutron source.
The vast majority of everyday phenomena do not involve nuclear reactions. Most everyday phenomena only involve gravity and electromagnetism. Gravitation is a natural Phenomenon by which objects with Mass attract one another Electromagnetism is the Physics of the Electromagnetic field: a field which exerts a Force on particles that possess the property of Of the fundamental forces of nature, they are not the strongest, but the other two, the strong nuclear force and the weak nuclear force are essentially short-range forces so they do not play a role outside the atomic nucleus. In Physics, a fundamental interaction or fundamental force is a mechanism by which particles interact with each other and which cannot be explained in terms In particle physics the strong interaction, or strong force, or color force, holds Quarks and Gluons together to form Protons and The weak interaction (often called the weak force or sometimes the weak nuclear force) is one of the four Fundamental interactions of nature Atomic nuclei are generally kept apart because they contain positive electrical charges and therefore repel each other, so in ordinary circumstances they cannot meet.
Nuclear Accidents
Three Mile island Incident (1979)
The Three Mile Island incident, which ironically occurred two weeks after the release of the disaster film The China Syndrome greatly impacted the public's perception of nuclear power. The Three Mile Island accident of 1979 was the most significant accident in the history of the American commercial Nuclear power generating industry The China Syndrome is a 1979 Thriller film which tells the story of a reporter and cameraman who discover safety coverups at a Nuclear power Many human factors engineering improvements were made to American power plants in the wake of Three Mile Island's partial meltdown. See also The Human Factor (disambiguation. Human factors is a term that covers The science of understanding the properties [2]
Chernobyl Accident (1986)
The Chernobyl accident in 1986 further alarmed the public about nuclear power. The Chernobyl disaster was a nuclear reactor accident in the Chernobyl Nuclear Power Plant in the Soviet Union. Year 1986 ( MCMLXXXVI) was a Common year starting on Wednesday (link displays 1986 Gregorian calendar) While design differences between the RBMK reactor used at Chernobyl and most western reactors virtually eliminate the possibility of such an accident occurring outside of the former Soviet Union, it is only recently that the general public in the United States has started to embrace nuclear energy. RBMK is an acronym for the Russian reaktor bolshoy moshchnosti kanalniy (Реактор Большой Мощности Канальный which means "High Power Channel
Examples of Nuclear Technology
Nuclear Power
- Further information: 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 power is any Nuclear technology designed to extract usable Energy from atomic nuclei via controlled Nuclear reactions 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 can be used for mechanical work and also to generate electricity.
Currently nuclear power is used to propel aircraft carriers, icebreakers and submarines; and provides approximately 15. An aircraft carrier is a Warship designed with An icebreaker is a special purpose Ship or Boat designed to move and navigate through Ice -covered waters A submarine is a Watercraft that can operate independently below water as distinct from a Submersible that has only limited underwater capability 7% of the world's electricity (in 2004). The risk of radiation and cost have prohibited use of nuclear power in transport ships. [3]
Medical Applications
Imaging - medical and dental x-ray imagers use of Cobalt-60 or other x-ray sources. Technetium-99m is used, attached to organic molecules, as radioactive tracer in the human body, before being excreted by the kidneys. Technetium-99m is a metastable Nuclear isomer of technetium-99 symbolized as 99mTc Positron emitting nulceotides are used for high resolution, short time span imaging in applications known as Positron emission tomography. Positron emission tomography ( PET) is a Nuclear medicine imaging technique which produces a three-dimensional image or map of functional processes in the
Industrial applications
Oil and Gas Exploration- Nuclear well logging is used to help predict the commercial viability of new or existing wells. Well logging, also known as borehole logging is the practice of making a detailed record (a well log) of the Geologic formations penetrated by a borehole The technology involves the use of a neutron or gamma-ray source and a radiation detector which are lowered into boreholes to determine the properties of the surrounding rock such as porosity and lithography. [1]
Road Construction - Nuclear moisture/density gauges are used to determine the density of soils, asphalt, and concrete. Typically a Cesium-137 source is used.
Commercial applications
An ionization smoke detector includes a tiny mass of radioactive americium-241, which is a source of alpha radiation. A smoke detector is a device that detects Smoke and issues an Alarm. Americium (ˌæməˈrɪsiəm is a Synthetic element that has the symbol Am and Atomic number 95 Alpha decay is a type of radioactive decay in which an Atomic nucleus emits an Alpha particle (two protons and two neutrons bound together into a particle Tritium is used with phosphor in rifle sights to increase nighttime firing accuracy. Tritium (ˈtɹɪtiəm symbol or, also known as Hydrogen-3) is a radioactive Isotope of Hydrogen. A phosphor is a substance that exhibits the phenomenon of Phosphorescence (sustained glowing after exposure to energized particles such as Electrons Luminescent exit signs use the same technology. [4]
Food Processing and Agriculture
Food irradiation[5] is the process of exposing food to ionizing radiation in order to destroy microorganisms, bacteria, viruses, or insects that might be present in the food. Image talkNew_radiation_symbol_ISO_21482svg for details --> Ionizing radiation A microorganism (also spelled micro organism or micro-organism and also called a microbe) is an Organism that is Microscopic (usually The Bacteria ( singular: bacterium) are a large group of unicellular Microorganisms Typically a few Micrometres in length bacteria have A virus (from the Latin virus meaning Toxin or Poison) is a sub-microscopic infectious agent that is unable Insects ( Class Insecta) are a major group of Arthropods and the most diverse group of Animals on the Earth with over a million described Further applications include sprout inhibition, delay of ripening, increase of juice yield, and improvement of re-hydration. 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). Irradiation is the process by which an item is exposed to Radiation. 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 every-day 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. Deoxyribonucleic acid ( DNA) is a Nucleic acid that contains the genetic instructions used in the development and functioning of all known Microorganisms can no longer proliferate and continue their malignant or pathogen activities. Spoilage causing micro-organisms cannot continue their activities. Insects do not survive or become incapable of proliferation. Plants cannot continue the natural ripening or aging process. All these effects are beneficial to the consumer and the food industry, likewise. [5]
It should be noted that the amount of energy imparted for effective food irradiation is low compared to cooking the same; even at a typical dose of 10 kGy most food, which is (with regard to warming) physically equivalent to water, would warm by only about 2. 5 °C.
The speciality of processing food by ionizing radiation is 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 is controversial, because pasteurization and irradiation are fundamentally different processes, although the intended end results can in some cases be similar.
Food irradiation is currently permitted by over 40 countries and volumes are estimated to exceed 500 000 metric tons annually world wide. [6] [7] [8]
References
- ^ Henri Becquerel
- ^ Human Performance Technology and the Accident at Three Mile Island
- ^ Nuclear-powered Ships
- ^ Tritium Information
- ^ a b anon. , Food Irradiation - A technique for preserving and improving the safety of food, WHO, Geneva, 1991
- ^ NUCLEUS - Food Irradiation Clearances
- ^ Food irradiation, Position of ADA, J Am Diet Assoc. 2000;100:246-253. http://www.mindfully.org/Food/Irradiation-Position-ADA.htm retrieved 2007-11-15
- ^ C. M. Deeley, M. Gao, R. Hunter, D. A. E. Ehlermann, The development of food irradiation in the Asia Pacific, the Americas and Europe; tutorial presented to the International Meeting on Radiation Processing, Kuala Lumpur, 2006. http://www.doubleia.org/index.php?sectionid=43&parentid=13&contentid=494 last visited 2007-11-16
See also
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