Editing Nuclear technology (section)

== Civilian uses ==

===Nuclear power===
{{Further|Nuclear power|Nuclear reactor technology}}
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 15.7% of the world's electricity (in 2004) and is used to propel [[aircraft carrier]]s, [[icebreaker]]s and [[submarine]]s (so far economics and fears in some ports have prevented the use of nuclear power in transport ships).<ref>{{cite web|url=http://world-nuclear.org/info/inf34.html|title=Nuclear-Powered Ships - Nuclear Submarines - World Nuclear Association|website=world-nuclear.org|access-date=9 May 2018|url-status=live|archive-url=https://web.archive.org/web/20130214062612/http://www.world-nuclear.org/info/inf34.html|archive-date=14 February 2013}}</ref> All [[nuclear power plant]]s use fission. No man-made fusion reaction has resulted in a viable source of electricity.

===Medical applications===
{{Further|Nuclear medicine}}
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 [[radiopharmaceutical]]s 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 time span imaging in applications known as [[Positron emission tomography]].

Radiation is also used to treat diseases in [[radiation therapy]].

===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 [[nondestructive 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 <sup>241</sup>[[Americium|Am]] 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 tracer]]s''' - 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:
*Adding a 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 boreholes to determine the properties of the surrounding rock such as porosity and lithography.[http://hps.org/publicinformation/radterms/radfact154.html]

'''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===
*[[radioluminescence]]
*[[tritium illumination]]: [[Tritium]] is used with [[phosphor]] in rifle sights to increase nighttime firing accuracy. Some runway markers and building exit signs use the same technology, to remain illuminated during blackouts.<ref>{{cite web|url=http://www.physics.isu.edu/radinf/tritium.htm|title=ISU Health Physics Radinf|website=www.physics.isu.edu|access-date=9 May 2018|url-status=live|archive-url=https://web.archive.org/web/20170921123842/http://www.physics.isu.edu/radinf/tritium.htm|archive-date=21 September 2017}}</ref>
*[[Betavoltaics]].
*Smoke detector: An ionization [[smoke detector]] includes a tiny mass of radioactive [[americium]]-241, which is a source of [[alpha radiation]]. Two ionisation chambers are placed next to each other. Both contain a small source of <sup>241</sup>[[Americium|Am]] 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 attach 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.

===Food processing and agriculture===

In [[biology]] and [[agriculture]], radiation is used to induce [[mutation]]s to produce new or improved species, such as in [[atomic gardening]]. Another use in [[insect control]] is 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 [[Radiation sterilization|sterilization]] of tools and equipment. An advantage is that the object may be sealed in plastic before sterilization. An emerging use in [[food production]] is the sterilization of food using [[food irradiation]].

[[File:Radura-Symbol.svg|thumb|150px|right|The [[Radura]] logo, used to show that a food has been treated with ionizing radiation.]] 
Food irradiation<ref name="FI">anon., Food Irradiation - A technique for preserving and improving the safety of food, WHO, Geneva, 1991</ref> is the process of exposing food to [[ionizing radiation]] in order to destroy [[microorganism]]s, [[bacteria]], [[virus]]es, or [[insect]]s 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, 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). 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 [[DNA sequence|genetic information]] for life. Microorganisms can no longer proliferate and continue their malignant or pathogenic activities. Spoilage causing micro-organisms 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.<ref name="FI"/>

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&nbsp;°C (4.5&nbsp;°F).

The specialty 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.

Detractors of food irradiation have concerns about the health hazards of [[induced radioactivity]].{{citation needed|date=November 2010}} A report for the industry advocacy group [[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."<ref>{{cite web |url=http://www.acsh.org/docLib/20040331_irradiated2003.pdf |title=IRRADIATED FOODS Fifth Edition Revised and updated by Paisan Loaharanu May 2003 AMERICAN COUNCIL ON SCIENCE AND HEALTH |access-date=2012-03-05 |url-status=dead |archive-url=https://web.archive.org/web/20110926205822/http://www.acsh.org/docLib/20040331_irradiated2003.pdf |archive-date=2011-09-26 }}</ref>

Food irradiation is currently permitted by over 40 countries and volumes are estimated to exceed {{convert|500000|MT}} annually worldwide.<ref>[http://nucleus.iaea.org/NUCLEUS/nucleus/Content/Applications/FICdb/FoodIrradiationClearances.jsp?module=cif NUCLEUS - Food Irradiation Clearances] {{webarchive|url=https://web.archive.org/web/20080526025627/http://nucleus.iaea.org/NUCLEUS/nucleus/Content/Applications/FICdb/FoodIrradiationClearances.jsp?module=cif |date=2008-05-26 }}</ref><ref>[http://www.mindfully.org/Food/Irradiation-Position-ADA.htm Food irradiation, Position of ADA] {{webarchive|url=https://web.archive.org/web/20160216174601/http://www.mindfully.org/Food/Irradiation-Position-ADA.htm |date=2016-02-16 }}. J Am Diet Assoc. 2000;100:246-253. retrieved 2007-11-15.</ref><ref name="IMRP2006">C.M. Deeley, M. Gao, R. Hunter, D.A.E. Ehlermann. {{usurped|1=[https://web.archive.org/web/20170202002120/http://doubleia.org/index.php?sectionid=43&parentid=13&contentid=494 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. last visited 2007-11-16.  {{dead link|date=June 2016|bot=medic}}{{cbignore|bot=medic}}</ref>

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.