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Nuclear power is the use of nuclear reactions that release nuclear energy to generate heat, which most frequently is then used in steam turbines to produce electricity in a nuclear power station. The term includes nuclear fission, nuclear decay and nuclear fusion. Presently, the nuclear fission of elements in the actinide series of the periodic table produce the vast majority of nuclear energy in the direct service of humankind, with nuclear decay processes, primarily in the form of geothermal energy, and radioisotope thermoelectric generators, in niche uses making up the rest. Nuclear (fission) power stations, excluding the contribution from naval nuclear fission reactors, provided 11% of the world's electricity in 2012,〔 〕 somewhat less than that generated by hydro-electric stations at 16%. Since electricity accounts for about 25% of humanity's energy usage with the majority of the rest coming from fossil fuel reliant sectors such as transport, manufacture and home heating, nuclear fission's contribution to the global final energy consumption is about 2.5%,〔Nicola Armaroli, Vincenzo Balzani, ''Towards an electricity-powered world''. In: ''Energy and Environmental Science'' 4, (2011), 3193-3222, p. 3200, .〕 a little more than the combined global electricity production from "new renewables"; wind, solar, biofuel and geothermal power, which together provided 2% of global final energy consumption in 2014.〔(REN 21. RENEWABLES 2014 GLOBAL STATUS REPORT )〕 Regional differences in the use of fission energy are large. Fission energy generation, with a 20% share of the U.S. electricity production, is the single largest deployed technology among current low-carbon power sources in the country.〔(Issues in Science & Technology Online; “Promoting Low-Carbon Electricity Production” )〕 In addition, two-thirds of the European Union's twenty-seven nations's low-carbon energy is produced by fission.〔( The European Strategic Energy Technology Plan SET-Plan Towards a low-carbon future 2010. Nuclear power provides "2/3 of the EU's low carbon energy" pg 6. )〕 Some of these nations have banned its generation, such as Italy, which ended the use of fission-electric generation, which started in 1963, in 1990. France is the largest user of nuclear energy, deriving 75% of its electricity from fission. Along with other sustainable energy sources, nuclear fission power is a low carbon power generation method of producing electricity, meaning that it is in the renewable energy family of low associated greenhouse gas emissions per unit of energy generated. As all electricity supplying technologies use cement etc., during construction, emissions are yet to be brought to zero. A 2014 analysis of the carbon footprint literature by the Intergovernmental Panel on Climate Change (IPCC) reported that fission electricities embodied total life-cycle emission intensity value of 12 g eq/kWh is the lowest out of all commercial Baseload energy sources, and second lowest out of all commercial electricity technologies known, after wind power which is an Intermittent energy source with embodied greenhouse gas emissions, per unit of energy generated of 11 g eq/kWh. Each result is contrasted with coal & fossil gas at 820 and 490 g eq/kWh.〔〔 With this translating into, from the beginning of Fission-electric power station commercialization in the 1970s, having prevented the emission of about 64 billion tonnes of carbon dioxide equivalent, greenhouse gases that would have otherwise resulted from the burning of fossil fuels in thermal power stations. In 2013, the IAEA reported that there are 437 operational civil fission-electric reactors〔(【引用サイトリンク】title=PRIS - Home )〕 in 31 countries, although not every reactor is producing electricity. In addition, there are approximately 140 naval vessels using nuclear propulsion in operation, powered by some 180 reactors.〔(【引用サイトリンク】title=What is Nuclear Power Plant - How Nuclear Power Plants work | What is Nuclear Power Reactor - Types of Nuclear Power Reactors )〕〔(【引用サイトリンク】title=Nuclear-Powered Ships | Nuclear Submarines )〕〔http://www.ewp.rpi.edu/hartford/~ernesto/F2010/EP2/Materials4Students/Misiaszek/NuclearMarinePropulsion.pdf Naval Nuclear Propulsion, Magdi Ragheb. ''As of 2001, about 235 naval reactors had been built''〕 As of 2013, attaining a net energy gain from sustained nuclear fusion reactions, excluding natural fusion power sources such as the Sun, remains an ongoing area of international physics and engineering research. With commercial fusion power production remaining unlikely before 2050.〔 - Projected fusion power timeline〕 In 2015, the IAEA report that worldwide there were 67 civil fission-electric power reactors under construction in 15 countries including Gulf states such as the United Arab Emirates (UAE).〔 Over half of the 67 total being built are in Asia, with 28 in the Peoples Republic of China (PRC), with the most recently completed fission-electric reactor to be connected to the electrical grid, as of August 2015, occurring in Wolseong Nuclear Power Plant in the Republic of Korea.〔(South Korea’s Shin-Wolsong-2 Enters Commercial Operation )〕 Five other new grid connections were completed by the PRC so far this year.〔(【引用サイトリンク】title=Grid Connection for Fuqing-2 in China 7 August 2015 )〕 In the USA, four new Generation III reactors are under construction at Vogtle and Summer station, while a fifth is nearing completion at Watts Bar station, all five are expected to enter service before 2020. In 2013, four aging uncompetitive U.S reactors were closed. There is a social debate about nuclear power.〔James J. MacKenzie. (Review of The Nuclear Power Controversy ) by Arthur W. Murphy ''The Quarterly Review of Biology'', Vol. 52, No. 4 (Dec., 1977), pp. 467-468.〕〔In February 2010 the nuclear power debate played out on the pages of the ''New York Times'', see (A Reasonable Bet on Nuclear Power ) and (Revisiting Nuclear Power: A Debate ) and (A Comeback for Nuclear Power? )〕 Proponents, such as the World Nuclear Association and Environmentalists for Nuclear Energy, contend that nuclear power is a safe, sustainable energy source that reduces carbon emissions.〔(U.S. Energy Legislation May Be 'Renaissance' for Nuclear Power ).〕 Opponents, such as Greenpeace International and NIRS, contend that nuclear power poses many threats to people and the environment.〔(【引用サイトリンク】title=Nuclear Power )〕 Far reaching fission power reactor accidents, or accidents that resulted in medium to long-lived fission product contamination of inhabited areas, have occurred in Generation I & II reactor designs, blueprinted between 1950 and 1980. These include the Chernobyl disaster which occurred in 1986, the Fukushima Daiichi nuclear disaster (2011), and the more contained Three Mile Island accident (1979).〔 There have also been some nuclear submarine accidents.〔(Strengthening the Safety of Radiation Sources ) p. 14.〕 In terms of lives lost per unit of energy generated, analysis has determined that fission-electric reactors have caused less fatalities per unit of energy generated than the other major sources of energy generation. Energy production from coal, petroleum, natural gas and hydroelectricity has caused a greater number of fatalities per unit of energy generated due to air pollution and energy accident effects.〔http://www.forbes.com/sites/jamesconca/2012/06/10/energys-deathprint-a-price-always-paid/ with Chernobyl's total predicted linear no-threshold cancer deaths included, nuclear power is safer when compared to many alternative energy sources' immediate, death rate.〕〔 If you cannot access the paper via the above link, the following link is open to the public, credit to the authors. http://gabe.web.psi.ch/pdfs/_2012_LEA_Audit/TA01.pdf Page 962 to 965. Comparing Nuclear's ''latent'' cancer deaths, such as cancer with other energy sources ''immediate'' deaths per unit of energy generated(GWeyr). This study does not include Fossil fuel related cancer and other indirect deaths created by the use of fossil fuel consumption in its "severe accident", an accident with more than 5 fatalities, classification.〕 However, the economic costs of nuclear power accidents is high, and meltdowns can render areas uninhabitable for very long periods. The human costs of evacuations of affected populations and lost livelihoods is also significant. Japan's 2011 Fukushima Daiichi nuclear disaster, which occurred in a reactor design from the 1960s, prompted a re-examination of nuclear safety and nuclear energy policy in many countries.〔 Germany plans to close all its reactors by 2022, and Italy has re-affirmed its ban on electric utilities generating, but not importing, fission derived electricity. In 2011 the International Energy Agency halved its prior estimate of new generating capacity to be built by 2035. In 2013 Japan signed a deal worth $22 billion, in which Mitsubishi Heavy Industries would build four modern ''Atmea'' reactors for Turkey. In August 2015, following 4 years of near zero fission-electricity generation, Japan began restarting its fission fleet, after safety upgrades were completed, beginning with Sendai fission-electric station.〔(August 11, 2015, Kyushu Electric Power Company Inc. Startup of Sendai Nuclear Power Unit No.1 )〕 ==Use== In 2011 nuclear power provided 10% of the world's electricity〔 In 2007, the IAEA reported there were 439 nuclear power reactors in operation in the world,〔 (【引用サイトリンク】 title= Nuclear Power Plants Information. Number of Reactors Operation Worldwide ) 〕 operating in 31 countries.〔 However, many have now ceased operation in the wake of the Fukushima nuclear disaster while they are assessed for safety. In 2011 worldwide nuclear output fell by 4.3%, the largest decline on record, on the back of sharp declines in Japan (-44.3%) and Germany (-23.2%).〔 (【引用サイトリンク】 title=BP Statistical Review of World Energy June 2012 )〕 Since commercial nuclear energy began in the mid-1950s, 2008 was the first year that no new nuclear power plant was connected to the grid, although two were connected in 2009.〔Trevor Findlay (2010). (The Future of Nuclear Energy to 2030 and its Implications for Safety, Security and Nonproliferation: Overview ), The Centre for International Governance Innovation (CIGI), Waterloo, Ontario, Canada, pp. 10-11.〕〔Mycle Schneider, Steve Thomas, Antony Froggatt, and Doug Koplow (August 2009). (The World Nuclear Industry Status Report 2009 ) Commissioned by German Federal Ministry of Environment, Nature Conservation and Reactor Safety, p. 5. 〕 Annual generation of nuclear power has been on a slight downward trend since 2007, decreasing 1.8% in 2009 to 2558 TWh with nuclear power meeting 13–14% of the world's electricity demand.〔 One factor in the nuclear power percentage decrease since 2007 has been the prolonged shutdown of large reactors at the Kashiwazaki-Kariwa Nuclear Power Plant in Japan following the Niigata-Chuetsu-Oki earthquake.〔World Nuclear Association. (Another drop in nuclear generation ) ''World Nuclear News'', 05 May 2010.〕 The United States produces the most nuclear energy, with nuclear power providing 19%〔 〕 of the electricity it consumes, while France produces the highest percentage of its electrical energy from nuclear reactors—80% as of 2006.〔 〕 In the European Union as a whole, nuclear energy provides 30% of the electricity.〔 〕 Nuclear energy policy differs among European Union countries, and some, such as Austria, Estonia, Ireland and Italy, have no active nuclear power stations. In comparison, France has a large number of these plants, with 16 multi-unit stations in current use. In the US, while the coal and gas electricity industry is projected to be worth $85 billion by 2013, nuclear power generators are forecast to be worth $18 billion.〔(''Nuclear Power Generation, US Industry Report" ) IBISWorld, August 2008''〕 Many military and some civilian (such as some icebreaker) ships use nuclear marine propulsion, a form of nuclear propulsion.〔 〕 A few space vehicles have been launched using full-fledged nuclear reactors: 33 reactors belong to the Soviet RORSAT series and one was the American SNAP-10A. International research is continuing into safety improvements such as passively safe plants,〔 the use of nuclear fusion, and additional uses of process heat such as hydrogen production (in support of a hydrogen economy), for desalinating sea water, and for use in district heating systems. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Nuclear power」の詳細全文を読む スポンサード リンク
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