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{{short description|Power generated from nuclear reactions}}
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{{For|countries with the power or ability to project nuclear weapons|List of states with nuclear weapons}}
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[[File:2011-05-10 18-57-46 Switzerland - Wil crop.jpg|thumb|The [[Leibstadt Nuclear Power Plant]] in Switzerland]]
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'''Nuclear power''' is the use of [[nuclear reaction]]s to produce [[electricity]]. Nuclear power can be obtained from [[nuclear fission]], [[nuclear decay]] and [[nuclear fusion]] reactions. Presently, the vast majority of electricity from nuclear power is produced by nuclear ''fission'' of [[uranium]] and [[plutonium]] in [[nuclear power plant]]s. Nuclear ''decay'' processes are used in niche applications such as [[radioisotope thermoelectric generator]]s in some space probes such as ''[[Voyager 2]]''.<ref>{{Cite web |title=Power: Radioisotope Thermoelectric Generators - NASA Science |url=https://science.nasa.gov/planetary-science/programs/radioisotope-power-systems/power-radioisotope-thermoelectric-generators/ |access-date=2024-10-01 |website=science.nasa.gov |date=8 February 2024 |language=en-US}}</ref> Reactors producing controlled [[fusion power|''fusion'' power]] have been operated since 1958 but have yet to generate net power and are not expected to be commercially available in the near future.<ref>{{cite book |last1=Moynihan |first1=M. |last2=Bortz |first2=A. B. |title=Fusion's Promise: How Technological Breakthroughs in Nuclear Fusion Can Conquer Climate Change on Earth (And Carry Humans To Mars, Too) |publisher=Springer International Publishing |year=2023 |doi=10.1007/978-3-031-22906-0 |bibcode=2023fpht.book.....M |isbn=978-3-031-22905-3 }}</ref>

The [[first nuclear power plant]] was built in the 1950s. The global installed nuclear capacity grew to 100{{nbsp}}GW in the late 1970s, and then expanded during the 1980s, reaching 300{{nbsp}}GW by 1990. The 1979 [[Three Mile Island accident]] in the [[United States]] and the 1986 [[Chernobyl disaster]] in the [[Soviet Union]] resulted in increased regulation and public opposition to nuclear power plants. Nuclear power plants supplied 2,602 [[terawatt hour]]s (TWh) of electricity in 2023, equivalent to about 9% of [[global electricity generation]],<ref name="PerformanceReport">{{Cite report |title=World Nuclear Performance Report 2024 |date=2024 |url=https://world-nuclear.org/images/articles/World-Nuclear-Performance-Report-2024.pdf |access-date=2024-11-10 |publisher=World Nuclear Association |pages=3–5}}</ref> and were the second largest [[low-carbon power]] source after [[hydroelectricity]]. {{As of|2025|11|post=,}} there are [[List of nuclear reactors|416 civilian fission reactors in the world]], with overall capacity of 376{{nbsp}}GW,<ref name=":3">{{Cite web |title=Power Reactor Information System |url=https://pris.iaea.org/pris/home.aspx |access-date=2024-11-10 |publisher=International Atomic Energy Agency }}</ref> 63 under construction and 87 planned, with a combined capacity of 66{{nbsp}}GW and 84{{nbsp}}GW, respectively.<ref name="WNA" /> The United States has the largest fleet of nuclear reactors, generating almost 800{{nbsp}}TWh per year with an average [[capacity factor]] of 92%. The average global capacity factor is 89%.<ref name=":3" /> Most new reactors under construction are [[generation III reactor]]s in Asia.

Nuclear power is a safe, sustainable energy source that reduces [[carbon emissions]]. This is because nuclear power generation causes one of the lowest levels of fatalities per unit of energy generated compared to other energy sources. "Economists estimate that each nuclear plant built could save more than 800,000 life years."<ref>{{Cite web |last=Bailey |first=Ronald |date=2024-11-29 |title=Nuclear energy prevents air pollution and saves lives |url=https://reason.com/2024/11/29/nuclear-power-saves-lives/?utm_medium=reason_email&utm_source=new_at_reason&utm_campaign=reason_brand&utm_content=Joe%20Biden%20Rarely%20Issues%20Pardons%20but%20Made%20an%20Exception%20for%20His%20Son&utm_term=&time=December%202nd,%202024&mpid=38717&mpweb=2534-5108-38717 |access-date=2024-12-05 |website=Reason.com |language=en-US}}</ref> Coal, petroleum, [[natural gas]] and hydroelectricity have each caused more fatalities per unit of energy due to [[air pollution]] and [[Energy accidents|accidents]]. Nuclear power plants also emit no [[greenhouse gases]] and result in less life-cycle carbon emissions than common sources of [[renewable energy]]. The radiological hazards associated with nuclear power are the primary motivations of the [[anti-nuclear movement]], which contends that nuclear power poses threats to people and the environment, citing the potential for [[Nuclear and radiation accidents and incidents|accidents]] like the [[Fukushima nuclear disaster]] in Japan in 2011, and is too expensive to deploy when compared to alternative [[sustainable energy]] sources.{{TOC limit}}

==History==
{{main|History of nuclear power|Timeline of nuclear power}}

===Origins===
[[File:First four nuclear lit bulbs.jpeg|thumb|The first light bulbs ever lit by electricity generated by nuclear power at [[EBR-1]] at [[Argonne National Laboratory]]-West (now the [[Idaho National Laboratory]]), December 20, 1951.<ref>{{cite web |title=Reactors: Modern-Day Alchemy - Argonne's Nuclear Science and Technology Legacy |url=https://www.ne.anl.gov/About/modern-day-alchemy/ |website=www.ne.anl.gov |access-date=24 March 2021}}</ref>]]
The process of nuclear fission was discovered in 1938 after over four decades of work on the science of [[radioactivity]] and the elaboration of new [[nuclear physics]] that described the components of [[atom]]s. Soon after the discovery of the fission process, it was realized that neutrons released by a fissioning nucleus could, under the right conditions, induce fissions in nearby nuclei, thus initiating a [[nuclear chain reaction|self-sustaining chain reaction]].<ref name="Inside the Atomic Patent Office">{{cite journal | doi = 10.2968/064002008 | volume=64 | issue=2 | title=Inside the atomic patent office | year=2008 | journal=Bulletin of the Atomic Scientists | pages=26–31 | last1 = Wellerstein | first1 = Alex| bibcode=2008BuAtS..64b..26W  |issn = 0096-3402 | doi-access=free }}</ref> Once this was experimentally confirmed in 1939, scientists in many countries petitioned their governments for support for nuclear fission research, just on the cusp of [[World War II]], in order to develop a [[nuclear weapon]].<ref>{{cite web |url=http://www.atomicarchive.com/History/mp/introduction.shtml |title=The Einstein Letter |publisher=Atomicarchive.com |access-date=2013-06-22 |archive-date=2013-06-28 |archive-url=https://web.archive.org/web/20130628151924/http://www.atomicarchive.com/History/mp/introduction.shtml |url-status=live }}</ref>

In the United States, these research efforts led to the creation of the first human-made [[nuclear reactor]], the [[Chicago Pile-1]] under the [[Stagg Field]] stadium at the [[University of Chicago]], which achieved [[Criticality (status)|criticality]] on December 2, 1942. The reactor's development was part of the [[Manhattan Project]], the [[Allies of World War II|Allied]] effort to create [[atomic bombs]] during World War II. It led to the building of larger single-purpose [[production reactor]]s for the production of [[weapons-grade plutonium]] for use in the first nuclear weapons. The United States tested the first nuclear weapon in July 1945, the [[Trinity test]], and the [[atomic bombings of Hiroshima and Nagasaki]] happened one month later.<ref>{{cite web |title=Timeline - Nuclear Museum |url=https://ahf.nuclearmuseum.org/ahf/nuc-history/timeline/ |website=ahf.nuclearmuseum.org/ |access-date=4 September 2025}}</ref>

[[File:Nautiluscore.jpg|thumb| The launching ceremony of {{USS|Nautilus|SSN-571|6}} January 1954. In 1958 it would become the first vessel to reach the [[North Pole]].<ref>{{cite web |title=Nautilus (SSN-571) |url=https://www.history.navy.mil/browse-by-topic/ships/uss-nautilus.html |archive-url=https://web.archive.org/web/20150721063358/http://www.history.navy.mil/browse-by-topic/ships/uss-nautilus.html |archive-date=July 21, 2015 |publisher=US Naval History and Heritage Command (US Navy)}}</ref>]]
[[File:HD.15.019 (11823864155).jpg|thumb|The [[Calder Hall nuclear power station]] in the United Kingdom, the world's first commercial nuclear power station]]
Despite the military nature of the first nuclear devices, there was strong optimism in the 1940s and 1950s that nuclear power could provide cheap and endless energy.<ref>{{cite book |last1=Wendt |first1=Gerald |last2=Geddes |first2=Donald Porter |title=The Atomic Age Opens |date=1945 |publisher=Pocket Books |location=New York |url=http://alsos.wlu.edu/information.aspx?id=279 |access-date=2017-11-03 |archive-date=2016-03-28 |archive-url=https://web.archive.org/web/20160328104803/http://alsos.wlu.edu/information.aspx?id=279 }}</ref> Electricity was generated for the first time by a nuclear reactor on December 20, 1951, at the [[EBR-I]] experimental station near [[Arco, Idaho]], which initially produced about 100{{nbsp}}[[kW]].<ref>{{cite web |url=http://www.ne.anl.gov/About/reactors/frt.shtml |title=Reactors Designed by Argonne National Laboratory: Fast Reactor Technology |publisher=U.S. Department of Energy, Argonne National Laboratory |year=2012 |access-date=2012-07-25 |archive-date=2021-04-18 |archive-url=https://web.archive.org/web/20210418094852/https://www.ne.anl.gov/About/reactors/frt.shtml |url-status=live }}</ref><ref>{{cite magazine| url=https://books.google.com/books?id=yNwDAAAAMBAJ&q=1954+Popular+Mechanics+January&pg=PA105 |title=Reactor Makes Electricity |magazine=Popular Mechanics |date= March 1952| page= 105|publisher=Hearst Magazines }}</ref> In 1953, American President [[Dwight Eisenhower]] gave his "[[Atoms for Peace]]" speech at the [[United Nations]], emphasizing the need to develop "peaceful" uses of nuclear power quickly. This was followed by the [[Atomic Energy Act of 1954]] which allowed rapid declassification of U.S. reactor technology and encouraged development by the private sector.<ref name=usnrc_history>{{cite web |author1=J. Samuel Walker |author2=Thomas R. Wellock |title=A Short History of Nuclear Regulation, 1946–2009 |url=https://www.nrc.gov/docs/ML1029/ML102980443.pdf |publisher=U.S. Nuclear Regulatory Commission |access-date=4 September 2025 |page=2}}</ref>

===First power generation===
The first organization to develop practical nuclear power was the [[U.S. Navy]], with the [[S1W reactor]] for the purpose of propelling [[submarine]]s and [[aircraft carrier]]s. The first nuclear-powered submarine, {{USS|Nautilus|SSN-571|6}}, was put to sea in January 1954.<ref name="iaeapdf" /><ref>{{cite web |url=http://www.ne.anl.gov/About/reactors/lwr3.shtml#fragment-2 |title=STR (Submarine Thermal Reactor) in "Reactors Designed by Argonne National Laboratory: Light Water Reactor Technology Development" |publisher=U.S. Department of Energy, Argonne National Laboratory |year=2012 |access-date=2012-07-25 |archive-date=2012-06-22 |archive-url=https://web.archive.org/web/20120622185310/http://www.ne.anl.gov/About/reactors/lwr3.shtml#fragment-2 |url-status=live }}</ref> The S1W reactor was a [[pressurized water reactor]]. This design was chosen because it was simpler, more compact, and easier to operate compared to alternative designs, thus more suitable to be used in submarines. This decision would result in the PWR being the reactor of choice also for power generation, thus having a lasting impact on the civilian electricity market in the years to come.<ref>{{cite book|last=Rockwell|first=Theodore|title=The Rickover Effect|publisher=Naval Institute Press|year=1992|page=162|isbn=978-1-55750-702-0}}</ref>

On June 27, 1954, the [[Obninsk Nuclear Power Plant]] in the [[USSR]] became the world's first nuclear power plant to generate electricity for a [[power grid]], producing around 5 megawatts of electric power.<ref name="IAEANews">{{cite web |url=http://www.iaea.org/NewsCenter/News/2004/obninsk.html |title=From Obninsk Beyond: Nuclear Power Conference Looks to Future |website=[[International Atomic Energy Agency]] |access-date=2006-06-27 |date=2004-06-23 |archive-date=2006-11-15 |archive-url=https://web.archive.org/web/20061115165641/http://www.iaea.org/NewsCenter/News/2004/obninsk.html |url-status=live }}</ref> The world's first commercial nuclear power station, [[Calder Hall]] at Windscale, England was connected to the national power grid on 27 August 1956. In common with a number of other [[generation I reactor]]s, the plant had the dual purpose of producing [[electricity]] and [[plutonium-239]], the latter for the nascent [[Nuclear weapons and the United Kingdom|nuclear weapons program in Britain]].<ref>{{cite book |last1=Hill |first1=C. N. |title=An atomic empire: a technical history of the rise and fall of the British atomic energy programme |date=2013 |publisher=Imperial College Press |isbn=978-1-908977-43-4 |location=London, England}}</ref>

===Expansion and first opposition===
The total global installed nuclear capacity initially rose relatively quickly, rising from less than 1 [[gigawatt]] (GW) in 1960 to 100{{nbsp}}GW in the late 1970s.<ref name="iaeapdf">{{cite web |url=http://www.iaea.org/About/Policy/GC/GC48/Documents/gc48inf-4_ftn3.pdf |title=50 Years of Nuclear Energy |access-date=2006-11-09 |publisher=International Atomic Energy Agency |archive-date=2010-01-07 |archive-url=https://web.archive.org/web/20100107093607/http://www.iaea.org/About/Policy/GC/GC48/Documents/gc48inf-4_ftn3.pdf |url-status=live }}</ref> During the 1970s and 1980s rising economic costs (related to extended construction times largely due to regulatory changes and pressure-group litigation)<ref name="Bernard L. Cohen 1990">{{cite book |author=Bernard L. Cohen |date=1990 |title=The Nuclear Energy Option: An Alternative for the 90s |url=https://archive.org/details/nuclearenergyopt0000cohe |location=New York |publisher=Plenum Press |isbn=978-0-306-43567-6 |url-access=registration }}</ref> and falling fossil fuel prices made nuclear power plants then under construction less attractive. In the 1980s in the U.S. and 1990s in Europe, the flat electric grid growth and [[electricity liberalization]] also made the addition of large new [[baseload]] energy generators economically unattractive.{{cn|date=August 2025}}

The [[1973 oil crisis]] had a significant effect on countries, such as [[France]] and [[Japan]], which had relied more heavily on oil for electric generation to invest in nuclear power.<ref>{{cite web |author=Beder |first=Sharon |date=2006 |title=The Japanese Situation, English version of conclusion of Sharon Beder, "Power Play: The Fight to Control the World's Electricity" |url=http://www.herinst.org/sbeder/privatisation/japan.html |url-status=live |archive-url=https://web.archive.org/web/20110317160509/http://www.herinst.org/sbeder/privatisation/japan.html |archive-date=2011-03-17 |access-date=2009-05-15 |publisher=Soshisha, Japan}}</ref> France would construct 25 nuclear power plants over the next 15 years,<ref name="palfreman">{{Cite news| last = Palfreman| first = Jon| title = Why the French Like Nuclear Energy| work = [[Frontline (U.S. TV series)|Frontline]]| publisher = [[Public Broadcasting Service]]| access-date = 25 August 2007| year = 1997| url = https://www.pbs.org/wgbh/pages/frontline/shows/reaction/readings/french.html| archive-date = 25 August 2007| archive-url = https://web.archive.org/web/20070825003225/http://www.pbs.org/wgbh/pages/frontline/shows/reaction/readings/french.html| url-status = live}}</ref><ref name="de preneuf">{{cite web |last=de Preneuf |first=Rene |title=Nuclear Power in France&nbsp;– Why does it Work? |url=http://www.npcil.nic.in/nupower_vol13_2/npfr_.htm |archive-url=https://web.archive.org/web/20070813233335/http://www.npcil.nic.in/nupower_vol13_2/npfr_.htm <!-- Bot retrieved archive --> |archive-date=13 August 2007 |access-date=25 August 2007}}</ref> and as of 2019, 71% of French electricity was generated by nuclear power, the highest percentage by any nation in the world.<ref name=":0" />

Some local opposition to nuclear power emerged in the United States in the early 1960s.<ref name="well">{{cite journal |author=Garb |first=Paula |year=1999 |title=Review of Critical Masses: Opposition to Nuclear Power in California, 1958–1978 |url=http://jpe.library.arizona.edu/volume_6/wellockvol6.htm |journal=Journal of Political Ecology |volume=6 |archive-url=https://web.archive.org/web/20180601112114/http://jpe.library.arizona.edu/volume_6/wellockvol6.htm |archive-date=2018-06-01 |access-date=2011-03-14}}</ref> In the late 1960s, some members of the scientific community began to express pointed concerns.<ref name=wolfgang /> These [[anti-nuclear]] concerns related to [[nuclear accidents]], [[nuclear proliferation]], [[nuclear terrorism]] and [[High-level radioactive waste management|radioactive waste disposal]].<ref name="bm">{{cite journal |author=Martin |first=Brian |author-link=Brian Martin (social scientist) |date=2007 |title=Opposing nuclear power: past and present |url=http://www.bmartin.cc/pubs/07sa.html |url-status=live |journal=Social Alternatives |volume=26 |pages=43–47 |archive-url=https://web.archive.org/web/20190510124855/https://www.bmartin.cc/pubs/07sa.html |archive-date=2019-05-10 |access-date=2011-03-14 |number=2}}</ref> In the early 1970s, there were large protests about a proposed nuclear power plant in [[Wyhl]], Germany. The project was cancelled in 1975. The anti-nuclear success at Wyhl inspired opposition to nuclear power in other parts of Europe and North America.<ref name="pub">{{cite book |last1=Mills |first1=Stephen |url=https://books.google.com/books?id=SeMNAAAAQAAJ&q=%22public+acceptance+of+new+technologies%22 |title=Public acceptance of new technologies: an international review |last2=Williams |first2=Roger |date=1986 |publisher=Croom Helm |isbn=978-0-7099-4319-8 |location=London |pages=375–376}}</ref><ref name=got>Robert Gottlieb (2005). [https://books.google.com/books?id=lR0n6oqMNPkC&dq=transofrmation+of+the+american+environmental+gottlieb+revised&pg=PP1 Forcing the Spring: The Transformation of the American Environmental Movement], Revised Edition, Island Press, p. 237.</ref>

By the mid-1970s [[anti-nuclear]] activism gained a wider appeal and influence, and nuclear power began to become an issue of major public protest.<ref name="jimfalk">{{cite book |last=Falk |first=Jim |url=https://archive.org/details/globalfissionbat00falk |title=Global Fission: The Battle Over Nuclear Power |date=1982 |publisher=Oxford University Press |isbn=978-0-19-554315-5 |location=Melbourne, Australia |pages=[https://archive.org/details/globalfissionbat00falk/page/95 95–96] |url-access=registration}}</ref><ref name="eleven">Walker, J. Samuel (2004). ''[https://books.google.com/books?id=tf0AfoynG-EC&q=Three+Mile+Island:+A+Nuclear+Crisis+in+Historical+Perspective Three Mile Island: A Nuclear Crisis in Historical Perspective] {{Webarchive|url=https://web.archive.org/web/20230323071157/https://books.google.com/books?id=tf0AfoynG-EC&q=Three+Mile+Island:+A+Nuclear+Crisis+in+Historical+Perspective|date=2023-03-23}}'' (Berkeley, California: University of California Press), pp. 10–11.</ref> In some countries, the [[Nuclear power debate|nuclear power conflict]] "reached an intensity unprecedented in the history of technology controversies".<ref name="marcuse.org">{{cite journal |author=Herbert P. Kitschelt |date=1986 |title=Political Opportunity and Political Protest: Anti-Nuclear Movements in Four Democracies |url=http://www.marcuse.org/harold/hmimages/seabrook/861KitscheltAntiNuclear4Democracies.pdf |journal=British Journal of Political Science |volume=16 |issue=1 |page=57 |doi=10.1017/s000712340000380x |s2cid=154479502 |access-date=2010-02-28 |archive-date=2010-08-21 |archive-url=https://web.archive.org/web/20100821195323/http://www.marcuse.org/harold/hmimages/seabrook/861KitscheltAntiNuclear4Democracies.pdf |url-status=live }}</ref><ref name="kits">{{cite journal |author=Kitschelt |first=Herbert P. |date=1986 |title=Political Opportunity and Political Protest: Anti-Nuclear Movements in Four Democracies |url=http://www.marcuse.org/harold/hmimages/seabrook/861KitscheltAntiNuclear4Democracies.pdf |url-status=live |journal=British Journal of Political Science |volume=16 |issue=1 |page=71 |doi=10.1017/s000712340000380x |s2cid=154479502 |archive-url=https://web.archive.org/web/20100821195323/http://www.marcuse.org/harold/hmimages/seabrook/861KitscheltAntiNuclear4Democracies.pdf |archive-date=2010-08-21 |access-date=2010-02-28}}</ref> The increased public hostility to nuclear power led to a longer license procurement process, more regulations and increased requirements for safety equipment, which made new construction much more expensive.<ref name="phyast.pitt.edu">{{cite web |title=Costs of Nuclear Power Plants – What Went Wrong? |url=http://www.phyast.pitt.edu/~blc/book/chapter9.html |website=www.phyast.pitt.edu |access-date=2007-12-04 |archive-date=2010-04-13 |archive-url=https://web.archive.org/web/20100413204335/http://www.phyast.pitt.edu/~blc/book/chapter9.html |url-status=live }}</ref><ref>{{cite news |last1=Ginn |first1=Vance |last2=Raia |first2=Elliott |date=August 18, 2017 |title=nuclear energy may soon be free from its tangled regulatory web |url=https://www.washingtonexaminer.com/nuclear-energy-may-soon-be-free-from-its-tangled-regulatory-web |url-status=live |archive-url=https://web.archive.org/web/20190106204903/https://www.washingtonexaminer.com/nuclear-energy-may-soon-be-free-from-its-tangled-regulatory-web |archive-date=January 6, 2019 |access-date=January 6, 2019 |work=Washington Examiner}}</ref> In the United States, over [[List of cancelled nuclear reactors in the United States|120 Light Water Reactor proposals were ultimately cancelled]]<ref>{{cite web | url=https://fas.org/sgp/crs/misc/RL33442.pdf | title=Nuclear Power: Outlook for New U.S. Reactors | page=3 | access-date=2015-10-18 | archive-date=2015-09-24 | archive-url=https://web.archive.org/web/20150924134344/http://www.fas.org/sgp/crs/misc/RL33442.pdf | url-status=live }}</ref> and the construction of new reactors ground to a halt.<ref name="ReferenceA">{{cite journal |date=1985-02-11 |title=Nuclear Follies |journal=Forbes Magazine|last=Cook|first=James}}</ref> The 1979 [[Three Mile Island accident|accident at Three Mile Island]] with no fatalities, played a major part in the reduction in the number of new plant constructions in many countries.<ref name="wolfgang">{{cite book |url=https://books.google.com/books?id=ZXwfAQAAIAAJ |title=Anti-nuclear Movements: A World Survey of Opposition to Nuclear Energy |publisher=Longman Current Affairs |year=1990 |isbn=978-0-8103-9000-3 |editor1-last=Rüdig |editor1-first=Wolfgang |location=Detroit, Michigan |page=1 |language=en-us}}</ref>

===Chernobyl and renaissance===
[[File:Центр города Припять на фоне 4 энергоблокаа ЧАЭС.jpg|thumb|The town of [[Pripyat (city)|Pripyat]] abandoned since 1986, with the Chernobyl plant and the [[Chernobyl New Safe Confinement]] arch in the distance]]
[[File:OL3.jpg|thumb|[[Olkiluoto 3]] under construction in 2009. It was the first [[EPR (nuclear reactor)|EPR]], a modernized PWR design, to start construction. ]]
During the 1980s one new nuclear reactor started up every 17&nbsp;days on average.<ref>{{cite book |last1=Thorpe |first1=Gary S. |title=AP Environmental Science, 6th ed. |date=2015 |publisher=Barrons Educational Series |isbn=978-1-4380-6728-5}} {{ISBN|1-4380-6728-3}}</ref> By the end of the decade, global installed nuclear capacity reached 300{{nbsp}}GW. Since the late 1980s, new capacity additions slowed significantly, with the installed nuclear capacity reaching 365{{nbsp}}GW in 2005.<ref>{{cite web |title=PRIS - Trend reports - Unit Capability |url=https://pris.iaea.org/PRIS/WorldStatistics/WorldTrendinUnitCapabilityFactor.aspx |website=pris.iaea.org |publisher=International Atomic Energy Agency |access-date=5 September 2025}}</ref>

The 1986 [[Chernobyl disaster]] in the [[USSR]], involving an [[RBMK]] reactor, altered the development of nuclear power and led to a greater focus on meeting international safety and regulatory standards.<ref>{{cite web|url=https://www.iaea.org/newscenter/focus/chernobyl|title=Chernobyl Nuclear Accident|date=14 May 2014|website=www.iaea.org|publisher=IAEA|access-date=23 March 2021|archive-date=11 June 2008|archive-url=https://web.archive.org/web/20080611102751/http://www.iaea.org/NewsCenter/Focus/Chernobyl/|url-status=live}}</ref> It is considered the worst nuclear disaster in history both in total casualties, with 56 direct deaths, and financially, with the cleanup and the cost estimated at 18{{nbsp}}billion{{nbsp}}[[Soviet rouble|Rbl]]s (US$68{{nbsp}}billion in 2019, adjusted for inflation).<ref name="OECD02-Ch2">{{cite web|url=https://www.oecd-nea.org/rp/reports/2003/nea3508-chernobyl.pdf|title=Chernobyl: Assessment of Radiological and Health Impact, 2002 update; Chapter II – The release, dispersion and deposition of radionuclides|year=2002|publisher=OECD-NEA|access-date=3 June 2015|archive-url=https://web.archive.org/web/20150622010856/https://www.oecd-nea.org/rp/reports/2003/nea3508-chernobyl.pdf|archive-date=22 June 2015|url-status=live}}</ref><ref name="GorbachevBoC">{{cite AV media |url=https://www.andanafilms.com/catalogueFiche.php?idFiche=255&rub=Toutes%20les%20fiches%20films |title=The battle of Chernobyl |date=2006 |publisher=Play Film / Discovery Channel |access-date=2021-03-23 |archive-url=https://web.archive.org/web/20210307205137/https://www.andanafilms.com/catalogueFiche.php?idFiche=255&rub=Toutes%20les%20fiches%20films |archive-date=2021-03-07 |url-status=live |people=Johnson, Thomas (author/director)}} (see 1996 interview with Mikhail Gorbachev.)</ref> The international organization to promote safety awareness and the professional development of [[reactor operator|operators in nuclear facilities]], the [[World Association of Nuclear Operators]] (WANO), was created as a direct outcome of the 1986 Chernobyl accident. The Chernobyl disaster played a major part in the reduction in the number of new plant constructions in the following years.<ref name=wolfgang/> Influenced by these events, Italy voted against nuclear power in a 1987 referendum,<ref>{{Cite book |last=Sassoon |first=Donald |url=https://books.google.com/books?id=W8K3AwAAQBAJ&dq=Italy+voted+against+nuclear+power+in+a+1987+referendum&pg=PT179 |title=Contemporary Italy: Politics, Economy and Society Since 1945 |date=2014-06-03 |publisher=Routledge |isbn=978-1-317-89377-6 |language=en}}</ref> becoming the first major economy to completely phase out nuclear power in 1990.<ref>{{cite web |last1=Saltori |first1=Massimiliano |title=Italy Votes to Include Nuclear Power In the National Energy Mix |url=https://earth.org/italy-nuclear/ |website=Earth.Org |access-date=5 September 2025 |language=en |date=17 May 2023}}</ref>

In the early 2000s, nuclear energy was expecting a [[nuclear renaissance]], an increase in the construction of new reactors, due to concerns about [[carbon dioxide emissions]].<ref name=":1">{{cite news |date=2011-03-14 |title=Analysis: Nuclear renaissance could fizzle after Japan quake |work=Reuters |url=https://www.reuters.com/article/us-japan-quake-nuclear-analysis-idUSTRE72C41W20110314 |access-date=2011-03-14 |archive-date=2015-12-08 |archive-url=https://web.archive.org/web/20151208211554/http://www.reuters.com/article/us-japan-quake-nuclear-analysis-idUSTRE72C41W20110314 |url-status=live }}</ref> During this period, newer [[generation III reactor]]s, such as the [[EPR (nuclear reactor)|EPR]] began construction.<ref>{{cite web |title=Nuclear Reactors: Generation to Generation {{!}} American Academy of Arts and Sciences |url=https://www.amacad.org/publication/nuclear-reactors-generation-generation/section/5 |website=www.amacad.org |publisher=American Academy of Arts & Sciences |access-date=5 September 2025}}</ref>
{{clear}}
<gallery mode="packed" heights="130px" style="text-align:left">
Global electricity generation by energy source.png|Net [[electrical generation]] by source and growth from 1980. In terms of energy generated between 1980 and 2010, the contribution from fission grew the fastest.
Electricity in France.svg|[[Electricity sector in France|Electricity production in France]], showing the shift to nuclear power. {{legend|#D55E00|thermofossil}}{{legend|#0072B2|hydroelectric}}{{legend|#F0E442|nuclear}}{{legend|#009E73|Other renewables}}
Nuclear-energy-timeline.svg|The rate of new reactor constructions essentially halted in the late 1980s. Increased [[capacity factor]] in existing reactors was primarily responsible for the continuing increase in electrical energy produced during this period.
Nuclear power generation in different countries.svg|Electricity generation trends in the top producing countries (Our World in Data)
</gallery>

===Fukushima accident===
{{Image frame
 |width = 520
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 |content={{Graph:Chart
 | width = 180
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 | type=area
 | interpolate=step-before
 | y= 2263.79 , 2298.27 , 2378.93 , 2443.85 , 2511.09 , 2553.18 , 2504.78 , 2616.24 , 2626.34 , 2660.85 , 2608.18 , 2597.81 , 2558.06 , 2629.82 , 2517.98 , 2346.19 , 2358.86 , 2410.37 , 2441.33 , 2477.30 , 2502.82 , 2562.76 , 2586.16
 | xAxisTitle=Year
 | xAxisAngle = -45
 | xType=date
 | yType=number
 | yAxisTitle=Generation (TWh)
 | x = 1997 ,1998 ,1999 , 2000 ,2001 ,2002 ,2003 ,2004 , 2005 ,2006 ,2007 ,2008 ,2009 , 2010 ,2011 ,2012 ,2013 ,2014 , 2015 , 2016, 2017, 2018, 2019
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 | x = 1997 ,1998 ,1999 , 2000 ,2001 ,2002 ,2003 ,2004 , 2005 ,2006 ,2007 ,2008 ,2009 , 2010 ,2011 ,2012 ,2013 ,2014 , 2015 , 2016, 2017, 2018, 2019
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|caption = Nuclear power generation (TWh) and operational nuclear reactors since 1997<ref name="pris-supplied">{{cite web |url=https://pris.iaea.org/PRIS/WorldStatistics/WorldTrendinElectricalProduction.aspx |title=Trend in Electricity Supplied |publisher=International Atomic Energy Agency |access-date=2021-01-09 |archive-date=2021-01-11 |archive-url=https://web.archive.org/web/20210111090143/https://pris.iaea.org/PRIS/WorldStatistics/WorldTrendinElectricalProduction.aspx |url-status=live }}</ref>
}}
Prospects of a nuclear renaissance were delayed by another nuclear accident.<ref name=":1" /><ref name=carbonbrief_2016>{{cite news |title=Analysis: The legacy of the Fukushima nuclear disaster |url=https://www.carbonbrief.org/analysis-the-legacy-of-the-fukushima-nuclear-disaster |access-date=24 March 2021 |work=Carbon Brief |date=10 March 2016 |language=en |archive-date=8 March 2021 |archive-url=https://web.archive.org/web/20210308035109/https://www.carbonbrief.org/analysis-the-legacy-of-the-fukushima-nuclear-disaster |url-status=live }}</ref> The 2011 [[Fukushima Daiichi nuclear accident]] was caused by the [[Tōhoku earthquake and tsunami]], one of the largest earthquakes ever recorded. The [[Fukushima Daiichi Nuclear Power Plant]] suffered three core meltdowns due to failure of the emergency cooling system for lack of electricity supply. This resulted in the most serious nuclear accident since the Chernobyl disaster.{{cn|date=August 2025}}

The accident prompted a re-examination of [[nuclear safety]] and [[nuclear energy policy]] in many countries.<ref name="sciamer2011">{{cite journal |last1=Westall |first1=Sylvia |last2=Dahl |first2=Fredrik |name-list-style=amp |date=2011-06-24 |title=IAEA Head Sees Wide Support for Stricter Nuclear Plant Safety |url=http://www.scientificamerican.com/article.cfm?id=iaea-head-sees-wide-support |journal=Scientific American |archive-url=https://archive.today/20110625042535/http://www.scientificamerican.com/article.cfm?id=iaea-head-sees-wide-support |archive-date=2011-06-25 |access-date=2011-06-25}}</ref> Germany approved plans to close all its reactors by 2022, and many other countries reviewed their nuclear power programs.<ref>{{cite news |author=Chandler |first=Jo |author-link=Jo Chandler |date=2011-03-19 |title=Is this the end of the nuclear revival? |url=https://www.smh.com.au/world/is-this-the-end-of-the-nuclear-revival-20110318-1c0i9.html |url-status=live |archive-url=https://web.archive.org/web/20200510043432/https://www.smh.com.au/environment/sustainability/is-this-the-end-of-the-nuclear-revival-20110318-1c0i9.html |archive-date=2020-05-10 |access-date=2020-02-20 |newspaper=The Sydney Morning Herald |publication-place=Sydney, Australia}}</ref><ref name="news.xinhuanet.com">{{cite news|url=http://news.xinhuanet.com/english2010/world/2011-03/18/c_13784578.htm |archive-url=https://web.archive.org/web/20110318184804/http://news.xinhuanet.com/english2010/world/2011-03/18/c_13784578.htm |archive-date=March 18, 2011 |title=Israeli PM cancels plan to build nuclear plant|work= xinhuanet.com|date=2011-03-18| access-date= 2011-03-17}}</ref> 
Following the disaster, Japan shut down all of its nuclear power reactors, some of them permanently, and in 2015 began a gradual process to restart the remaining 40 reactors, following safety checks and based on revised criteria for operations and public approval.<ref>{{cite web |url=http://www.kyuden.co.jp/en_information_150811.html |title=Startup of Sendai Nuclear Power Unit No.1 |date=2015-08-11 |website=Kyushu Electric Power Company Inc. |access-date=2015-08-12 |archive-url=https://web.archive.org/web/20170525170529/http://www.kyuden.co.jp/en_information_150811.html |archive-date=2017-05-25 }}</ref>

In 2022, the Japanese government, under the leadership of Prime Minister [[Fumio Kishida]], declared that 10 more nuclear power plants were to be reopened since the 2011 disaster.<ref>{{cite news |date=24 August 2022 |title=Japan turns back to nuclear power in post-Fukushima shift |url=https://www.ft.com/content/b380cb74-7b2e-493f-be99-281bd0dd478f |url-status=live |archive-url=https://web.archive.org/web/20220930125230/https://www.ft.com/content/b380cb74-7b2e-493f-be99-281bd0dd478f |archive-date=30 September 2022 |access-date=November 15, 2022 |newspaper=Financial Times |location=London, England}}</ref> Kishida is also pushing for research and construction of new safer nuclear plants to safeguard Japanese consumers from the fluctuating price of the fossil fuel market and reduce Japan's greenhouse gas emissions.<ref name="auto">{{cite web|url=https://reason.com/2022/08/25/japan-is-reopening-nuclear-power-plants-and-planning-to-build-new-ones/|title=Japan Is Reopening Nuclear Power Plants and Planning To Build New Ones|date=August 25, 2022|access-date=November 26, 2022|archive-date=November 15, 2022|archive-url=https://web.archive.org/web/20221115142242/https://reason.com/2022/08/25/japan-is-reopening-nuclear-power-plants-and-planning-to-build-new-ones/|url-status=live}}</ref> Kishida intends to have Japan become a significant exporter of nuclear energy and technology to developing countries around the world.<ref name="auto"/>

=== Current prospects ===
By 2015, the IAEA's outlook for nuclear energy had become more promising, recognizing the importance of low-carbon generation for mitigating [[climate change]].<ref>{{cite web|url=http://www.iea.org/newsroomandevents/news/2015/january/taking-a-fresh-look-at-the-future-of-nuclear-power.html|title=January: Taking a fresh look at the future of nuclear power|website=www.iea.org|access-date=2016-04-18|archive-date=2016-04-05|archive-url=https://web.archive.org/web/20160405120522/http://www.iea.org/newsroomandevents/news/2015/january/taking-a-fresh-look-at-the-future-of-nuclear-power.html|url-status=live}}</ref> {{As of|2015}}, the global trend was for new nuclear power stations coming online to be balanced by the number of old plants being retired.<ref>{{cite web |publisher=[[World Nuclear Association]] |url=http://www.world-nuclear.org/info/current-and-future-generation/plans-for-new-reactors-worldwide/ |title=Plans for New Reactors Worldwide |date=October 2015 |access-date=2016-01-05 |archive-date=2016-01-31 |archive-url=https://web.archive.org/web/20160131214224/http://www.world-nuclear.org/info/Current-and-Future-Generation/Plans-For-New-Reactors-Worldwide/ |url-status=live }}</ref> In 2016, the [[U.S. Energy Information Administration]] projected for its "base case" that world nuclear power generation would increase from 2,344 [[terawatt hour]]s (TWh) in 2012 to 4,500{{nbsp}}TWh in 2040. Most of the predicted increase was expected to be in Asia.<ref>{{cite web | url=http://www.eia.gov/forecasts/aeo/data/browser/#/?id=31-IEO2016&sourcekey=0 | title=International Energy outlook 2016 | publisher=US Energy Information Administration | access-date=17 August 2016 | archive-date=15 August 2016 | archive-url=https://web.archive.org/web/20160815223701/http://www.eia.gov/forecasts/aeo/data/browser/#/?id=31-IEO2016&sourcekey=0 | url-status=live }}</ref> As of 2018, there were over 150 nuclear reactors planned including 50 under construction.<ref>{{Cite web|title=Plans for New Nuclear Reactors Worldwide|url=http://www.world-nuclear.org/information-library/current-and-future-generation/plans-for-new-reactors-worldwide.aspx|access-date=2018-09-29|website=www.world-nuclear.org|publisher=World Nuclear Association|archive-date=2018-09-28|archive-url=https://web.archive.org/web/20180928230742/http://world-nuclear.org/information-library/current-and-future-generation/plans-for-new-reactors-worldwide.aspx|url-status=live}}</ref> In January 2019, China had 45 reactors in operation, 13 under construction, and planned to build 43 more, which would make it the world's largest generator of nuclear electricity.<ref name="china19">{{cite magazine |date=12 January 2019 |title=Can China become a scientific superpower? – The great experiment |url=https://www.economist.com/science-and-technology/2019/01/12/can-china-become-a-scientific-superpower |url-status=live |archive-url=https://web.archive.org/web/20190125020045/https://www.economist.com/science-and-technology/2019/01/12/can-china-become-a-scientific-superpower |archive-date=25 January 2019 |access-date=25 January 2019 |magazine=The Economist}}</ref> As of 2021, 17 reactors were reported to be under construction. Its share of electricity from nuclear power was 5% in 2019.<ref name="dwfrance">{{cite news |title=A global nuclear phaseout or renaissance? {{!}} DW {{!}} 04.02.2021 |url=https://www.dw.com/en/germany-looking-for-final-repository-for-nuclear-waste-global-outlook/a-56449115 |access-date=25 November 2021 |work=Deutsche Welle (www.dw.com) |archive-date=25 November 2021 |archive-url=https://web.archive.org/web/20211125101423/https://www.dw.com/en/germany-looking-for-final-repository-for-nuclear-waste-global-outlook/a-56449115 |url-status=live }}</ref> 

In October 2021, the Japanese cabinet approved the new Plan for Electricity Generation to 2030 prepared by the Agency for Natural Resources and Energy (ANRE) and an advisory committee, following public consultation. The nuclear target for 2030 requires the restart of another ten reactors. Prime Minister [[Fumio Kishida]] in July 2022 announced that the country should consider building advanced reactors and extending operating licences beyond 60 years.<ref>{{cite web|title=Nuclear Power in Japan|url=https://world-nuclear.org/information-library/country-profiles/countries-g-n/japan-nuclear-power.aspx|author=World Nuclear Association|access-date=2022-09-12|archive-date=2020-04-01|archive-url=https://web.archive.org/web/20200401112727/http://world-nuclear.org/information-library/country-profiles/countries-g-n/japan-nuclear-power.aspx|url-status=live}}</ref>

As of 2022, with world oil and gas prices on the rise, while Germany is restarting its coal plants to deal with loss of Russian gas that it needs to supplement its {{lang|de|[[Energiewende]]}},<ref>{{cite news| url=https://www.reuters.com/business/energy/germanys-uniper-bring-coal-fired-power-plant-heyden-4-back-onto-electricity-2022-08-22/| title=Germany's Uniper to restart coal-fired power plant as Gazprom halts supply to Europe| date=22 August 2022| publisher=Reuters| access-date=2022-09-12| archive-date=2022-09-09| archive-url=https://web.archive.org/web/20220909205007/https://www.reuters.com/business/energy/germanys-uniper-bring-coal-fired-power-plant-heyden-4-back-onto-electricity-2022-08-22/| url-status=live}}</ref> many other countries have announced ambitious plans to reinvigorate ageing nuclear generating capacity with new investments. French President [[Emmanuel Macron]] announced his intention to build six new reactors in coming decades, placing nuclear at the heart of France's drive for [[carbon neutrality]] by 2050.<ref>{{cite news |url = https://www.reuters.com/business/energy/macron-bets-nuclear-carbon-neutrality-push-announces-new-reactors-2022-02-10/ |publisher = Reuters |title = Macron bets on nuclear in carbon-neutrality push, announces new reactors |date = 10 February 2022 |access-date = 2022-09-12 |archive-date = 2022-09-14 |archive-url = https://web.archive.org/web/20220914080529/https://www.reuters.com/business/energy/macron-bets-nuclear-carbon-neutrality-push-announces-new-reactors-2022-02-10/ |url-status = live }}</ref> Meanwhile, in the United States, the [[Department of Energy]], in collaboration with commercial entities, [[TerraPower]] and [[X-energy]], is planning on building two different advanced nuclear reactors by 2027, with further plans for nuclear implementation in its long term green energy and energy security goals.<ref>{{cite news |url = https://www.science.org/content/article/department-energy-picks-two-advanced-nuclear-reactors-demonstration-projects |publisher = Science.org |title = Department of Energy picks two advanced nuclear reactors for demonstration projects, announces new reactors |date = 16 October 2020 |access-date = 3 March 2023 |archive-date = 24 February 2023 |archive-url = https://web.archive.org/web/20230224021201/https://www.science.org/content/article/department-energy-picks-two-advanced-nuclear-reactors-demonstration-projects |url-status = live }}</ref>

== Power plants ==
[[File:PWR nuclear power plant animation.webm|thumb|thumbtime=2|An animation of a [[pressurized water reactor]] in operation]]
{{pie chart
|radius=110
| label1 = PWR | value1 = 277 | color1 = #1f77b4
| label2 = BWR | value2 = 80 | color2 = #ff7f0e
| label3 = GCR | value3 = 15 | color3 = #2ca02c 
| label4 = PHWR | value4 = 49 | color4 = #d62728
| label5 = LWGR | value5 = 15 | color5 = #9467bd
| label6 = FBR | value6 = 2 | color6 = #8c564b
| caption= Number of electricity-generating civilian reactors by type as of 2014<ref name="IAEA_reactors_stats">{{cite web|title=Nuclear Power Reactors in the World – 2015 Edition|url=http://www-pub.iaea.org/MTCD/Publications/PDF/rds2-35web-85937611.pdf|publisher=International Atomic Energy Agency (IAEA)|access-date=26 October 2017|archive-date=16 November 2020|archive-url=https://web.archive.org/web/20201116191727/https://www-pub.iaea.org/MTCD/Publications/PDF/rds2-35web-85937611.pdf|url-status=live}}</ref>
}}
{{Main|Nuclear power plant|Nuclear reactor}}
{{See also|List of commercial nuclear reactors|List of nuclear power stations}}
Nuclear power plants are [[thermal power station]]s that generate electricity by harnessing the [[thermal energy]] released from [[nuclear fission]]. A fission nuclear power plant is generally composed of: a [[nuclear reactor]], in which the nuclear reactions generating heat take place; a cooling system, which removes the heat from inside the reactor; a [[steam turbine]], which transforms the heat into [[mechanical energy]]; an [[electric generator]], which transforms the mechanical energy into electrical energy.<ref name=WNAnuclearreactorbasics />

When a [[neutron]] hits the nucleus of a [[uranium-235]] or [[plutonium]] atom, it can split the nucleus into two smaller nuclei, which is a nuclear fission reaction. The reaction releases energy and neutrons. The released neutrons can hit other uranium or plutonium nuclei, causing new fission reactions, which release more energy and more neutrons. This is called a [[Nuclear chain reaction|chain reaction]]. In most commercial reactors, the reaction rate is contained by [[control rod]]s that absorb excess neutrons. The controllability of nuclear reactors depends on the fact that a small fraction of neutrons resulting from fission are [[Delayed neutron|delayed]]. The time delay between the fission and the release of the neutrons slows changes in reaction rates and gives time for moving the control rods to adjust the reaction rate.<ref name=WNAnuclearreactorbasics>{{cite web |title=How does a nuclear reactor make electricity? |publisher=World Nuclear Association |url=http://www.world-nuclear.org/nuclear-basics/how-does-a-nuclear-reactor-make-electricity.aspx |website=www.world-nuclear.org |access-date=24 August 2018 |archive-date=24 August 2018 |archive-url=https://web.archive.org/web/20180824134906/http://www.world-nuclear.org/nuclear-basics/how-does-a-nuclear-reactor-make-electricity.aspx |url-status=deviated }}</ref><ref>{{Cite news|url=https://www.scientificamerican.com/article/atomic-age-began-75-years-ago-with-the-first-controlled-nuclear-chain-reaction/|title=Atomic age began 75 years ago with the first controlled nuclear chain reaction|last1=Spyrou|first1=Artemis|date=2017-12-03|work=Scientific American|access-date=2018-11-18|last2=Mittig|first2=Wolfgang|archive-date=2018-11-18|archive-url=https://web.archive.org/web/20181118205736/https://www.scientificamerican.com/article/atomic-age-began-75-years-ago-with-the-first-controlled-nuclear-chain-reaction/|url-status=live}}</ref>

== Fuel cycle ==
[[File:Nuclear Fuel Cycle.png|thumb|The nuclear fuel cycle begins when uranium is mined, enriched, and manufactured into nuclear fuel (1), which is delivered to a [[nuclear power plant]]. After use, the spent fuel is delivered to a reprocessing plant (2) or to a final repository (3). In [[nuclear reprocessing]], 95% of spent fuel can potentially be recycled to be returned to use in a power plant (4).]]

{{Main|Nuclear fuel cycle|Integrated Nuclear Fuel Cycle Information System}}

The life cycle of nuclear fuel starts with [[uranium mining]]. The [[uranium ore]] is then converted into a compact [[ore concentrate]] form, known as [[yellowcake]] (U<sub>3</sub>O<sub>8</sub>), to facilitate transport.<ref name="nrc_fuel">{{cite web |title=Stages of the Nuclear Fuel Cycle |url=https://www.nrc.gov/materials/fuel-cycle-fac/stages-fuel-cycle.html |website=NRC Web |publisher=[[Nuclear Regulatory Commission]] |access-date=17 April 2021 |archive-date=20 April 2021 |archive-url=https://web.archive.org/web/20210420203721/https://www.nrc.gov/materials/fuel-cycle-fac/stages-fuel-cycle.html |url-status=live }}</ref> Fission reactors generally need [[uranium-235]], a [[fissile]] [[isotope of uranium]]. The concentration of uranium-235 in natural uranium is low (about 0.7%). Some reactors can use this natural uranium as fuel, depending on their [[neutron economy]]. These reactors generally have graphite or [[heavy water]] moderators. For light water reactors, the most common type of reactor, this concentration is too low, and it must be increased by a process called [[uranium enrichment]].<ref name="nrc_fuel"/> In civilian light water reactors, uranium is typically enriched to 3.5{{ndash}}5% uranium-235.<ref name="wna_fuel"/> The uranium is then generally converted into [[uranium oxide]] (UO<sub>2</sub>), a ceramic, that is then compressively [[sintered]] into fuel pellets, a stack of which forms [[fuel rod]]s of the proper composition and geometry for the particular reactor.<ref name="wna_fuel">{{cite web |title=Nuclear Fuel Cycle Overview |url=https://www.world-nuclear.org/information-library/nuclear-fuel-cycle/introduction/nuclear-fuel-cycle-overview.aspx |website=www.world-nuclear.org |publisher=World Nuclear Association |access-date=17 April 2021 |archive-date=20 April 2021 |archive-url=https://web.archive.org/web/20210420112134/https://www.world-nuclear.org/information-library/nuclear-fuel-cycle/introduction/nuclear-fuel-cycle-overview.aspx |url-status=live }}</ref>

After some time in the reactor, the fuel will have reduced fissile material and increased fission products, until its use becomes impractical.<ref name="wna_fuel"/> At this point, the spent fuel will be moved to a [[spent fuel pool]] which provides cooling for the thermal heat and shielding for ionizing radiation. After several months or years, the spent fuel is radioactively and thermally cool enough to be moved to dry storage casks or reprocessed.<ref name="wna_fuel"/>

=== Uranium resources ===
{{Main|Uranium market|Uranium mining|Energy development#Nuclear}}
[[File:Uranium enrichment proportions (horizontal).svg|upright=2|thumb|Proportions of the isotopes [[uranium-238]] (blue) and uranium-235 (red) found in natural uranium and in [[enriched uranium]] for different applications. Light water reactors use 3{{ndash}}5% enriched uranium, while [[CANDU]] reactors work with natural uranium.]]
[[Uranium]] is a fairly common [[chemical element|element]] in the Earth's crust: it is approximately as common as [[tin]] or [[germanium]], and is about 40 times more common than [[silver]].<ref>{{cite encyclopedia |url=http://www.encyclopedia.com/topic/uranium.aspx |title=uranium Facts, information, pictures &#124; Encyclopedia.com articles about uranium |encyclopedia=Encyclopedia.com |date=2001-09-11 |access-date=2013-06-14 |archive-date=2016-09-13 |archive-url=https://web.archive.org/web/20160913203913/http://www.encyclopedia.com/topic/uranium.aspx |url-status=live }}</ref> Uranium is present in trace concentrations in most rocks, dirt, and ocean water, but is generally economically extracted only where it is present in relatively high concentrations. As of 2011 the world's known resources of uranium, economically recoverable at the arbitrary price ceiling of US$130/kg, were enough to last for between 70 and 100 years in current reactors.<ref>{{cite web |url=http://www.spp.nus.edu.sg/docs/policy-briefs/201101_RSU_PolicyBrief_1-2nd_Thought_Nuclear-Sovacool.pdf |title=Second Thoughts About Nuclear Power |website=A Policy Brief – Challenges Facing Asia |date=January 2011 |archive-url=https://web.archive.org/web/20130116084833/http://spp.nus.edu.sg/docs/policy-briefs/201101_RSU_PolicyBrief_1-2nd_Thought_Nuclear-Sovacool.pdf |archive-date=January 16, 2013 |access-date=September 11, 2012 }}</ref>{{failed verification|date=September 2025}}

Light water reactors (which account for almost all operational reactors) make relatively inefficient use of nuclear fuel, mostly using only the very rare uranium-235 isotope.<ref name="wna-wmitnfc">{{cite web |url=http://www.world-nuclear.org/info/inf04.html |title=Waste Management in the Nuclear Fuel Cycle |access-date=2006-11-09 |publisher=World Nuclear Association |year=2006 |website=Information and Issue Briefs |archive-date=2010-06-11 |archive-url=https://web.archive.org/web/20100611201409/http://www.world-nuclear.org/info/inf04.html }}</ref> 
Limited uranium-235 supply may inhibit substantial expansion with the current nuclear technology.<ref name="sol1">{{cite journal |last1=Muellner |first1=Nikolaus |last2=Arnold |first2=Nikolaus |last3=Gufler |first3=Klaus |last4=Kromp |first4=Wolfgang |last5=Renneberg |first5=Wolfgang |last6=Liebert |first6=Wolfgang |title=Nuclear energy - The solution to climate change? |journal=Energy Policy |date=1 August 2021 |volume=155 |article-number=112363 |doi=10.1016/j.enpol.2021.112363 |s2cid=236254316 |language=en |issn=0301-4215|doi-access=free |bibcode=2021EnPol.15512363M }}</ref> 
[[Nuclear reprocessing]] can make this waste reusable, and newer reactors also achieve a more efficient use of the available resources than older ones.<ref name="wna-wmitnfc"/> 
More advanced nuclear reactor technologies, such as [[fast reactor]]s, can use much more of the natural uranium, use current nuclear waste as fuel, as well as creating new fuel out of non-fissile material (see [[breeder reactor]]). 
With a pure fast reactor fuel cycle with a burn up of all the uranium and [[actinide]]s (which presently make up the most hazardous substances in nuclear waste), there is an estimated 160,000 years worth of uranium in total conventional resources and phosphate ore at the price of 60–100 US$/kg.<ref>{{cite web |url=https://www.ipcc.ch/pdf/assessment-report/ar4/wg3/ar4-wg3-chapter4.pdf |title=Energy Supply |page=271 |archive-url=https://web.archive.org/web/20071215202932/http://www.ipcc.ch/pdf/assessment-report/ar4/wg3/ar4-wg3-chapter4.pdf |archive-date=2007-12-15}} and figure 4.10.</ref> 
These advanced fuel cycles and nuclear reprocessing are currently not widely used because the price of uranium is very low compared to the cost of nuclear plants, so it's more economically viable to mine new uranium rather than reprocess it. 
Nuclear reprocessing also carries higher risk of nuclear proliferation, as it separates material that can be used to manufacture nuclear weapons.<ref name="future1">{{cite web |title=Toward an Assessment of Future Proliferation Risk |url=https://cpb-us-e1.wpmucdn.com/blogs.gwu.edu/dist/3/1964/files/2021/03/Mark_Hibbs.pdf |access-date=25 November 2021 |archive-date=25 November 2021 |archive-url=https://web.archive.org/web/20211125145228/https://cpb-us-e1.wpmucdn.com/blogs.gwu.edu/dist/3/1964/files/2021/03/Mark_Hibbs.pdf |url-status=live }}</ref><ref name="civlib">{{cite journal |last1=Martin |first1=Brian |date=1 January 2015 |title=Nuclear power and civil liberties |url=https://ro.uow.edu.au/lhapapers/2126/ |url-status=live |journal=Faculty of Law, Humanities and the Arts – Papers (Archive) |pages=1–6 |archive-url=https://web.archive.org/web/20211125145241/https://ro.uow.edu.au/lhapapers/2126/ |archive-date=25 November 2021 |access-date=26 November 2021}}</ref><ref name="detect">{{cite journal |last1=Kemp |first1=R. Scott |title=Environmental Detection of Clandestine Nuclear Weapon Programs |journal=Annual Review of Earth and Planetary Sciences |date=29 June 2016 |volume=44 |issue=1 |pages=17–35 |doi=10.1146/annurev-earth-060115-012526 |bibcode=2016AREPS..44...17K |hdl=1721.1/105171 |url=https://www.annualreviews.org/doi/full/10.1146/annurev-earth-060115-012526 |language=en |issn=0084-6597 |quote=Although commercial reprocessing involves large, expensive facilities, some of which are identifiable in structure, a small, makeshift operation using standard industrial supplies is feasible (Ferguson 1977, US GAO 1978). Such a plant could be constructed to have no visual signatures that would reveal its location by overhead imaging, could be built in several months, and once operational could produce weapon quantities of fissile material in several days |hdl-access=free |access-date=26 November 2021 |archive-date=25 November 2021 |archive-url=https://web.archive.org/web/20211125145230/https://www.annualreviews.org/doi/full/10.1146/annurev-earth-060115-012526 |url-status=live }}</ref> 

Unconventional uranium resources also exist. Uranium is naturally present in seawater at a concentration of about 3 [[microgram]]s per liter,<ref name="books.google.ie">{{Cite book |last1=Ferronsky |first1=V. I. |url=https://books.google.com/books?id=OeEUcIRsIwAC&q=Radium+and+thorium+isotopes+in+the+surface+waters+of+the+East+Pacific+and+coastal+southern+California.+Earth+Planet.+Sci.+Lett.,+39:+235249.&pg=PA598 |title=Isotopes of the Earth's Hydrosphere |last2=Polyakov |first2=V. A. |publisher=Springer |year=2012 |isbn=978-94-007-2856-1 |page=399}}</ref> with 4.4 billion tons of uranium considered present in seawater at any time.<ref name="gepr.org" /> In 2014 it was suggested that it would be economically competitive to produce nuclear fuel from seawater if the process was implemented at large scale.<ref>{{Cite journal |doi=10.3390/jmse2010081|title=Development of a Kelp-Type Structure Module in a Coastal Ocean Model to Assess the Hydrodynamic Impact of Seawater Uranium Extraction Technology|journal=Journal of Marine Science and Engineering|volume=2|pages=81–92|year=2014|last1=Wang|first1=Taiping|last2=Khangaonkar|first2=Tarang|last3=Long|first3=Wen|last4=Gill|first4=Gary|issue=1 |doi-access=free|bibcode=2014JMSE....2...81W }}</ref> Over geological timescales, uranium extracted on an industrial scale from seawater would be replenished by both river erosion of rocks and the natural process of uranium [[leaching (metallurgy)|dissolved]] from the surface area of the ocean floor, both of which maintain the [[Solubility equilibrium|solubility equilibria]] of seawater concentration at a stable level.<ref name="gepr.org">{{cite web|url=http://www.gepr.org/en/contents/20130729-01/|title=The current state of promising research into extraction of uranium from seawater – Utilization of Japan's plentiful seas|first=Noriaki|last=Seko|publisher=Global Energy Policy Research|date=July 29, 2013|access-date=October 9, 2018|archive-date=October 9, 2018|archive-url=https://web.archive.org/web/20181009172251/http://www.gepr.org/en/contents/20130729-01/|url-status=live}}</ref> Some commentators have argued that this strengthens the case for [[Nuclear power proposed as renewable energy|nuclear power to be considered a renewable energy]].<ref>{{cite journal |vauthors=Alexandratos SD, Kung S |journal=Industrial & Engineering Chemistry Research |date=April 20, 2016 |volume=55 |issue=15 |pages=4101–4362 |title=Uranium in Seawater |doi=10.1021/acs.iecr.6b01293 |doi-access=free}}</ref>

=== Waste ===
{{main|Nuclear waste}}
[[File:Nuclear fuel composition.svg|upright=1.5|thumb|Typical composition of [[uranium dioxide]] fuel before and after approximately three years in the [[once-through nuclear fuel cycle]] of a [[LWR]]<ref name="jaif">{{cite web|url=http://www.jaif.or.jp/ja/wnu_si_intro/document/08-07-16-finck_philip.pdf | title=Current Options for the Nuclear Fuel Cycle |publisher=JAIF |author=Finck, Philip| archive-url=https://web.archive.org/web/20120412130546/http://www.jaif.or.jp/ja/wnu_si_intro/document/08-07-16-finck_philip.pdf | archive-date=2012-04-12 }}</ref>]]
The normal operation of nuclear power plants and facilities produce [[radioactive waste]], or nuclear waste. This type of waste is also produced during plant decommissioning. There are two broad categories of nuclear waste: low-level waste and high-level waste.<ref name=nrc_waste/> The first has low radioactivity and includes contaminated items such as clothing, which poses limited threat. High-level waste is mainly the spent fuel from nuclear reactors, which is very radioactive and must be cooled and then safely disposed of or reprocessed.<ref name=nrc_waste>{{cite web |title=Backgrounder on Radioactive Waste |url=https://www.nrc.gov/reading-rm/doc-collections/fact-sheets/radwaste.html |website=NRC |publisher=[[Nuclear Regulatory Commission]] |access-date=20 April 2021 |archive-date=13 November 2017 |archive-url=https://web.archive.org/web/20171113004118/https://www.nrc.gov/reading-rm/doc-collections/fact-sheets/radwaste.html |url-status=live }}</ref>

==== High-level waste ====
{{main|High-level waste|Spent nuclear fuel}}
[[File:Spent nuclear fuel decay sievert.jpg|thumb|upright=1.5|Activity of spent UOx fuel in comparison to the activity of natural [[uranium ore]] over time<ref name="m.phys.org">{{Cite web | url=https://m.phys.org/news/2017-11-fast-reactor-shorten-lifetime-long-lived.html |title = A fast reactor system to shorten the lifetime of long-lived fission products}}</ref><ref name="jaif"/>]]
[[File:Nuclear dry storage.jpg|thumb|[[Dry cask storage]] vessels storing spent nuclear fuel assemblies]]

The most important waste stream from nuclear power reactors is [[spent nuclear fuel]], which is considered [[high-level waste]] (HLW). For [[light water reactor]]s (LWRs), spent fuel is typically composed of 95% uranium, 4% [[fission product]]s, and about 1% [[transuranic]] [[actinides]] (mostly [[plutonium]], [[neptunium]] and [[americium]]).<ref>{{cite web |title=Radioactivity: Minor Actinides |url=http://www.radioactivity.eu.com/site/pages/Minor_Actinides.htm |website=www.radioactivity.eu.com |access-date=2018-12-23 |archive-date=2018-12-11 |archive-url=https://web.archive.org/web/20181211042617/http://www.radioactivity.eu.com/site/pages/Minor_Actinides.htm }}</ref> The fission products are responsible for the bulk of the short-term radioactivity, whereas the plutonium and other transuranics are responsible for the bulk of the long-term radioactivity.<ref>{{cite book |last1=Ojovan |first1=Michael I. |title=An introduction to nuclear waste immobilisation, second edition |date=2014 |publisher=Elsevier |location=Kidlington, Oxford, U.K. |isbn=978-0-08-099392-8 |edition=2nd}}</ref>

High-level waste must be stored isolated from the [[biosphere]] with sufficient shielding so as to limit radiation exposure. After being removed from the reactors, used fuel bundles are stored for six to ten years in [[spent fuel pool]]s, which provide cooling and shielding against radiation. After that, the fuel is cool enough that it can be safely transferred to [[dry cask storage]].<ref>{{Cite web|url=http://nuclearsafety.gc.ca/eng/waste/high-level-waste/index.cfm|title=High-level radioactive waste|publisher=Canadian Nuclear Safety Commission|date=February 3, 2014|website=nuclearsafety.gc.ca|access-date=April 19, 2022|archive-date=April 14, 2022|archive-url=https://web.archive.org/web/20220414190417/http://nuclearsafety.gc.ca/eng/waste/high-level-waste/index.cfm}}</ref> 
The radioactivity decreases exponentially with time, such that it will have decreased by 99.5% after 100 years.<ref>{{cite tech report |last1=Hedin |first1=A. |title=Spent nuclear fuel - how dangerous is it? A report from the project 'Description of risk' |date=1997 |url=https://www.osti.gov/etdeweb/biblio/587853 |publisher=Energy Technology Data Exchange}}</ref> 
The more intensely radioactive short-lived [[fission products]] (SLFPs) decay into stable elements in approximately 300 years, and after about 100,000 years, the spent fuel becomes less radioactive than natural uranium ore.<ref name="jaif"/><ref>{{cite book |last1=Bruno |first1=Jordi |last2=Duro |first2=Laura |last3=Diaz-Maurin |first3=François |date=2020 |title=Advances in Nuclear Fuel Chemistry |chapter=Chapter 13 – Spent nuclear fuel and disposal |series=Woodhead Publishing Series in Energy |pages=527–553 |chapter-url=https://www.sciencedirect.com/science/article/pii/B9780081025710000148 |publisher=Woodhead Publishing |doi=10.1016/B978-0-08-102571-0.00014-8 |isbn=978-0-08-102571-0 |s2cid=216544356 |access-date=2021-09-20 |archive-date=2021-09-20 |archive-url=https://web.archive.org/web/20210920212807/https://www.sciencedirect.com/science/article/pii/B9780081025710000148 |url-status=live }}</ref>

Commonly suggested methods to isolate long-lived fission product (LLFP) waste from the biosphere include separation and [[Nuclear transmutation|transmutation]],<ref name="jaif"/> [[synroc]] treatments, or deep geological storage.<ref>{{cite book |last1=Ojovan |first1=M. I. |title=An Introduction to Nuclear Waste Immobilisation |last2=Lee |first2=W. E. |publisher=Elsevier Science Publishers |year=2005 |isbn=978-0-08-044462-8 |location=Amsterdam, Netherlands |page=315}}</ref><ref>{{cite book |title=Technical Bases for Yucca Mountain Standards |author=National Research Council |year=1995 |publisher=National Academy Press |location=Washington, DC |isbn=978-0-309-05289-4|url=https://books.google.com/books?id=1DLyAtgVPy0C&pg=PA91|page=91}}</ref><ref>{{cite web |url=http://www.aps.org/units/fps/newsletters/2006/january/article1.html |title=The Status of Nuclear Waste Disposal |date=January 2006 |publisher=The American Physical Society |access-date=2008-06-06 |archive-date=2008-05-16 |archive-url=https://web.archive.org/web/20080516010935/http://www.aps.org/units/fps/newsletters/2006/january/article1.html |url-status=live }}</ref><ref>{{cite web |url=http://www.epa.gov/radiation/docs/yucca/70fr49013.pdf |title=Public Health and Environmental Radiation Protection Standards for Yucca Mountain, Nevada; Proposed Rule |date=2005-08-22 |publisher=United States Environmental Protection Agency |access-date=2008-06-06 |archive-date=2008-06-26 |archive-url=https://web.archive.org/web/20080626191551/http://www.epa.gov/radiation/docs/yucca/70fr49013.pdf }}</ref>

[[Thermal-neutron reactor]]s, which presently constitute the majority of the world fleet, cannot burn up the [[reactor grade plutonium]] that is generated during the reactor operation. This limits the life of nuclear fuel to a few years. In some countries, such as the United States, spent fuel is classified in its entirety as a nuclear waste.<ref>{{cite web |url=https://fas.org/sgp/crs/misc/RL32163.pdf |title=CRS Report for Congress. Radioactive Waste Streams: Waste Classification for Disposal |quote=The Nuclear Waste Policy Act of 1982 (NWPA) defined irradiated fuel as spent nuclear fuel, and the byproducts as high-level waste. |access-date=2018-12-22 |archive-date=2017-08-29 |archive-url=https://web.archive.org/web/20170829231541/https://fas.org/sgp/crs/misc/RL32163.pdf |url-status=live }}</ref> In other countries, such as France, it is largely reprocessed to produce a partially recycled fuel, known as mixed oxide fuel or [[MOX]]. 
For spent fuel that does not undergo reprocessing, the most concerning isotopes are the medium-lived [[transuranic element]]s, which are led by reactor-grade plutonium (with a [[half-life]] 24,000 years).<ref>{{harvnb|Vandenbosch|2007|p=21.|Ref=none}}</ref> 
Some proposed reactor designs, such as the [[integral fast reactor]] and [[molten salt reactor]]s, can use as fuel the plutonium and other actinides in spent fuel from light water reactors, thanks to their [[fast fission]] spectrum. This offers a potentially more attractive alternative to deep geological disposal.<ref>{{cite news |author=Clark |first=Duncan |date=2012-07-09 |title=Nuclear waste-burning reactor moves a step closer to reality |url=https://www.theguardian.com/environment/2012/jul/09/nuclear-waste-burning-reactor |url-status=live |archive-url=https://web.archive.org/web/20221008223126/https://www.theguardian.com/environment/2012/jul/09/nuclear-waste-burning-reactor |archive-date=2022-10-08 |access-date=2013-06-14 |newspaper=Guardian |location=London, England}}</ref><ref>{{cite web |author=Monbiot |first=George |date=5 December 2011 |title=A Waste of Waste |url=http://www.monbiot.com/2011/12/05/a-waste-of-waste/ |url-status=live |archive-url=https://web.archive.org/web/20130601052759/http://www.monbiot.com/2011/12/05/a-waste-of-waste/ |archive-date=2013-06-01 |access-date=2013-06-14 |publisher=Monbiot.com}}</ref><ref>{{cite web|url=https://www.youtube.com/watch?v=AZR0UKxNPh8  |archive-url=https://ghostarchive.org/varchive/youtube/20211211/AZR0UKxNPh8| archive-date=2021-12-11 |url-status=live|title=Energy From Thorium: A Nuclear Waste Burning Liquid Salt Thorium Reactor |publisher=YouTube |date=2009-07-23 |access-date=2013-06-14}}{{cbignore}}</ref>

The [[thorium fuel cycle]] results in similar fission products, though creates a much smaller proportion of transuranic elements from [[neutron capture]] events within a reactor. Spent thorium fuel, although more difficult to handle than spent uranium fuel, may present somewhat lower proliferation risks.<ref>{{cite web |title=Role of Thorium to Supplement Fuel Cycles of Future Nuclear Energy Systems |url=https://www-pub.iaea.org/MTCD/Publications/PDF/Pub1540_web.pdf |publisher=IAEA |access-date=7 April 2021 |date=2012 |quote=Once irradiated in a reactor, the fuel of a thorium–uranium cycle contains an admixture of 232U (half-life 68.9 years) whose radioactive decay chain includes emitters (particularly 208Tl) of high energy gamma radiation (2.6{{nbsp}}MeV). This makes spent thorium fuel treatment more difficult, requires remote handling/control during reprocessing and during further fuel fabrication, but on the other hand, may be considered as an additional non-proliferation barrier. |archive-date=6 May 2021 |archive-url=https://web.archive.org/web/20210506123715/https://www-pub.iaea.org/MTCD/publications/PDF/Pub1540_web.pdf |url-status=live }}</ref>

==== Low-level waste ====
{{main|Low-level waste}}

The nuclear industry also produces a large volume of [[low-level waste]], with low radioactivity, in the form of contaminated items like clothing, hand tools, water purifier resins, and (upon decommissioning) the materials of which the reactor itself is built. Low-level waste can be stored on-site until radiation levels are low enough to be disposed of as ordinary waste, or it can be sent to a low-level waste disposal site.<ref>{{cite web |title=NRC: Low-Level Waste |url=https://www.nrc.gov/waste/low-level-waste.html |website=www.nrc.gov |access-date=28 August 2018 |language=en |archive-date=17 August 2018 |archive-url=https://web.archive.org/web/20180817193533/https://www.nrc.gov/waste/low-level-waste.html |url-status=live }}</ref>

==== Waste relative to other types ====
{{See also|Radioactive waste#Naturally occurring radioactive material}}
In countries with nuclear power, radioactive wastes account for less than 1% of total industrial toxic wastes, much of which remains hazardous for long periods.<ref name="wna-wmitnfc" /> Overall, nuclear power produces far less waste material by volume than fossil-fuel based power plants.<ref>{{cite web|url=http://nuclearinfo.net/Nuclearpower/TheRisksOfNuclearPower|title=The Challenges of Nuclear Power|access-date=2013-01-04|archive-date=2017-05-10|archive-url=https://web.archive.org/web/20170510092527/http://nuclearinfo.net/Nuclearpower/TheRisksOfNuclearPower}}</ref> Coal-burning plants, in particular, produce large amounts of toxic and mildly radioactive ash resulting from the concentration of [[naturally occurring radioactive material]]s in coal.<ref>{{cite journal |date=2007-12-13 |title=Coal Ash Is More Radioactive than Nuclear Waste |url=http://www.scientificamerican.com/article.cfm?id=coal-ash-is-more-radioactive-than-nuclear-waste |journal=Scientific American |access-date=2012-09-11 |archive-date=2013-06-12 |archive-url=https://web.archive.org/web/20130612103809/http://www.scientificamerican.com/article.cfm?id=coal-ash-is-more-radioactive-than-nuclear-waste |url-status=live }}</ref> A 2008 report from [[Oak Ridge National Laboratory]] concluded that coal power actually results in more radioactivity being released into the environment than nuclear power operation, and that the population [[effective dose equivalent]] from radiation from coal plants is 100 times that from the operation of nuclear plants.<ref name="colmain">{{cite web |author=Gabbard |first=Alex |date=2008-02-05 |title=Coal Combustion: Nuclear Resource or Danger |url=http://www.ornl.gov/info/ornlreview/rev26-34/text/colmain.html |archive-url=https://web.archive.org/web/20070205103749/http://www.ornl.gov/info/ornlreview/rev26-34/text/colmain.html |archive-date=February 5, 2007 |access-date=2008-01-31 |publisher=Oak Ridge National Laboratory}}</ref> Although coal ash is much less radioactive than spent nuclear fuel by weight, coal ash is produced in much higher quantities per unit of energy generated. It is also released directly into the environment as [[fly ash]], whereas nuclear plants use shielding to protect the environment from radioactive materials.<ref name="cejournal">{{cite journal |date=2008-12-31 |title=Coal ash is ''not'' more radioactive than nuclear waste |url= http://www.cejournal.net/?p=410 |journal=CE Journal |archive-url=https://web.archive.org/web/20090827045039/http://www.cejournal.net/?p=410 |archive-date=2009-08-27 }}</ref>

Nuclear waste volume is small compared to the energy produced. For example, at [[Yankee Rowe Nuclear Power Station]], which generated 44 billion [[kilowatt hours]] of electricity when in service, its complete spent fuel inventory is contained within sixteen casks.<ref>{{cite web |url=http://www.yankeerowe.com/ |title=Yankee Nuclear Power Plant |publisher=Yankeerowe.com |access-date=2013-06-22 |archive-date=2006-03-03 |archive-url=https://web.archive.org/web/20060303073110/http://www.yankeerowe.com/ |url-status=live }}</ref> It is estimated that to produce a lifetime supply of energy for a person at a western [[standard of living]] (approximately 3{{nbsp}}[[GWh]]) would require on the order of the volume of a [[soda can]] of [[low enriched uranium]], resulting in a similar volume of spent fuel generated.<ref name="Generation Atomic">{{cite web|url=https://www.generationatomic.org/why-nuclear|title=Why nuclear energy|work=Generation Atomic|date=26 January 2021|access-date=22 December 2018|archive-date=23 December 2018|archive-url=https://web.archive.org/web/20181223073651/https://www.generationatomic.org/why-nuclear|url-status=live}}</ref><ref name="npr.org">{{cite news | url=https://www.npr.org/templates/story/story.php?storyId=125740818 | title=NPR Nuclear Waste May Get A Second Life | work=NPR | access-date=2018-12-22 | archive-date=2018-12-23 | archive-url=https://web.archive.org/web/20181223030055/https://www.npr.org/templates/story/story.php?storyId=125740818 | url-status=live }}</ref><ref>{{Cite web|url=https://hypertextbook.com/facts/1998/TommyZhou.shtml|title=Energy Consumption of the United States - The Physics Factbook|website=hypertextbook.com|access-date=2018-12-22|archive-date=2018-12-23|archive-url=https://web.archive.org/web/20181223073750/https://hypertextbook.com/facts/1998/TommyZhou.shtml|url-status=live}}</ref>

==== Waste disposal ====
{{See also|List of radioactive waste treatment technologies}}
[[File:WIPP-04.jpeg|alt=Storage of radioactive waste at WIPP|thumb|[[nuclear flask|Nuclear waste flasks]] generated by the United States during the Cold War are stored underground at the [[Waste Isolation Pilot Plant]] (WIPP) in [[New Mexico]]. The facility is seen as a potential demonstration for storing spent fuel from civilian reactors.]]
Following interim storage in a [[spent fuel pool]], the bundles of used fuel rod assemblies of a typical nuclear power station are often stored on site in [[dry cask storage]] vessels.<ref>{{cite web |url=https://www.nrc.gov/waste/spent-fuel-storage/dry-cask-storage.html |title=NRC: Dry Cask Storage |publisher=Nrc.gov |date=2013-03-26 |access-date=2013-06-22 |archive-date=2013-06-02 |archive-url=https://web.archive.org/web/20130602195818/http://www.nrc.gov/waste/spent-fuel-storage/dry-cask-storage.html |url-status=live }}</ref>

Disposal of nuclear waste is often considered the most politically divisive aspect in the lifecycle of a nuclear power facility.<ref name=mont2011>Montgomery, Scott L. (2010). ''The Powers That Be'', University of Chicago Press, p. 137.</ref> The lack of movement of nuclear waste in the 2 billion year old [[natural nuclear fission reactor]]s in [[Oklo]], [[Gabon]] is cited as "a source of essential information today."<ref>{{cite web |url= http://www.efn.org.au/NucWaste-Comby.pdf |title= international Journal of Environmental Studies, The Solutions for Nuclear waste, December 2005 |access-date= 2013-06-22 |archive-date= 2013-04-26 |archive-url= https://web.archive.org/web/20130426083758/http://www.efn.org.au/NucWaste-Comby.pdf }}</ref><ref>{{cite web |url= http://www.ocrwm.doe.gov/factsheets/doeymp0010.shtml |title=Oklo: Natural Nuclear Reactors |publisher=U.S. Department of Energy Office of Civilian Radioactive Waste Management, Yucca Mountain Project, DOE/YMP-0010|date=November 2004 |access-date=2009-09-15 |archive-url=https://web.archive.org/web/20090825013752/http://www.ocrwm.doe.gov/factsheets/doeymp0010.shtml |archive-date=2009-08-25 }}</ref> Experts suggest that centralized underground repositories which are well-managed, guarded, and monitored, would be a vast improvement.<ref name=mont2011 /> There is an "international consensus on the advisability of storing nuclear waste in [[deep geological repositories]]".<ref name=go /> With the advent of new technologies, other methods including [[horizontal drillhole disposal]] into geologically inactive areas have been proposed.<ref>{{Cite journal|title=Disposal of High-Level Nuclear Waste in Deep Horizontal Drillholes|date=May 29, 2019|journal=Energies|doi=10.3390/en12112052|last1=Muller|first1=Richard A.|last2=Finsterle|first2=Stefan|last3=Grimsich|first3=John|last4=Baltzer|first4=Rod|last5=Muller|first5=Elizabeth A.|last6=Rector|first6=James W.|last7=Payer|first7=Joe|last8=Apps|first8=John|volume=12|issue=11|page=2052|doi-access=free}}</ref><ref>{{Cite journal|title=The State of the Science and Technology in Deep Borehole Disposal of Nuclear Waste|date=February 14, 2020|journal=Energies|doi=10.3390/en13040833|last1=Mallants|first1=Dirk|last2=Travis|first2=Karl|last3=Chapman|first3=Neil|last4=Brady|first4=Patrick V.|last5=Griffiths|first5=Hefin|volume=13|issue=4|page=833|doi-access=free}}</ref>

[[File:Alpha-Gamma Hot Cell Facility 001.jpg|thumb|Most waste packaging, small-scale experimental fuel recycling chemistry and [[radiopharmaceutical]] refinement is conducted within remote-handled [[hot cell]]s.]]
There are no commercial scale purpose built underground high-level waste repositories in operation.<ref name="go">{{cite book |last=Gore |first=Al |url=https://archive.org/details/ourchoiceplantos00gore/page/165 |title=Our Choice: A Plan to Solve the Climate Crisis |date=2009 |publisher=Rodale |isbn=978-1-59486-734-7 |location=Emmaus, Pennsylvania |pages=[https://archive.org/details/ourchoiceplantos00gore/page/165 165–166] |url-access=registration}}</ref><ref>{{cite magazine| url= http://www.sciam.com/article.cfm?id=a-nuclear-renaissance&print=true| archive-url= https://archive.today/20120915104757/http://www.sciam.com/article.cfm?id=a-nuclear-renaissance&print=true| archive-date= 2012-09-15| title= A Nuclear Power Renaissance?| date= 2008-04-28| magazine= [[Scientific American]]| access-date= 2008-05-15}}</ref><ref>{{cite magazine | url= http://www.sciam.com/article.cfm?id=rethinking-nuclear-fuel-recycling | title= Nuclear Fuel Recycling: More Trouble Than It's Worth | last= von Hippel | first= Frank N. | author-link= Frank N. von Hippel | date= April 2008 | magazine= Scientific American | access-date= 2008-05-15 | archive-date= 2008-11-19 | archive-url= https://web.archive.org/web/20081119112436/http://www.sciam.com/article.cfm?id=rethinking-nuclear-fuel-recycling | url-status= live }}</ref> However, in Finland the [[Onkalo spent nuclear fuel repository]] of the [[Olkiluoto Nuclear Power Plant]] was under construction as of 2015.<ref>{{Cite web|url=http://www.world-nuclear-news.org/WR-Licence-granted-for-Finnish-used-fuel-repository-1211155.html|title=Licence granted for Finnish used fuel repository|date=2015-11-12|website=World Nuclear News|access-date=2018-11-18|archive-date=2015-11-24|archive-url=https://web.archive.org/web/20151124025533/http://world-nuclear-news.org/WR-Licence-granted-for-Finnish-used-fuel-repository-1211155.html|url-status=live}}</ref>

=== Reprocessing ===
{{main|Nuclear reprocessing}}
{{see also|Plutonium Management and Disposition Agreement}}

Most [[thermal-neutron reactor]]s run on a [[once-through nuclear fuel cycle]], mainly due to the low price of fresh uranium. However, many reactors are also fueled with recycled fissionable materials that remain in spent nuclear fuel. The most common fissionable material that is recycled is the [[reactor-grade plutonium]] (RGPu) that is extracted from spent fuel. It is mixed with uranium oxide and fabricated into mixed-oxide or [[MOX fuel]]. Because thermal LWRs remain the most common reactor worldwide, this type of recycling is the most common. It is considered to increase the sustainability of the nuclear fuel cycle, reduce the attractiveness of spent fuel to theft, and lower the volume of high level nuclear waste.<ref>{{Cite journal|doi=10.1016/j.energy.2014.02.069|title=Assessment of the environmental footprint of nuclear energy systems. Comparison between closed and open fuel cycles|journal=Energy|volume=69|pages=199–211|date=May 2014|last1=Poinssot|first1=Ch.|last2=Bourg|first2=S.|last3=Ouvrier|first3=N.|last4=Combernoux|first4=N.|last5=Rostaing|first5=C.|last6=Vargas-Gonzalez|first6=M.|last7=Bruno|first7=J.|doi-access=free|bibcode=2014Ene....69..199P }}</ref> Spent MOX fuel cannot generally be recycled for use in thermal-neutron reactors. This issue does not affect [[fast-neutron reactor]]s, which are therefore preferred in order to achieve the full energy potential of the original uranium.<ref name="berrytoll" /><ref name="IEEE Spectrum">{{cite news|last1=Fairley|first1=Peter|title=Nuclear Wasteland|url=https://spectrum.ieee.org/feb07/4891|work=IEEE Spectrum|date=February 2007|access-date=2020-02-02|archive-date=2020-08-05|archive-url=https://web.archive.org/web/20200805214749/https://spectrum.ieee.org/feb07/4891}}</ref>

The main constituent of spent fuel from LWRs is slightly [[enriched uranium]]. This can be recycled into [[reprocessed uranium]] (RepU), which can be used in a fast reactor, used directly as fuel in [[CANDU]] reactors, or re-enriched for another cycle through an LWR. Re-enriching of reprocessed uranium is common in France and Russia.<ref name="WNA3">{{cite web |url=http://www.world-nuclear.org/information-library/nuclear-fuel-cycle/fuel-recycling/processing-of-used-nuclear-fuel.aspx |title=Processing of Used Nuclear Fuel |date=2018 |publisher=World Nuclear Association |access-date=2018-12-26 |archive-date=2018-12-25 |archive-url=https://web.archive.org/web/20181225154511/http://www.world-nuclear.org/information-library/nuclear-fuel-cycle/fuel-recycling/processing-of-used-nuclear-fuel.aspx |url-status=live }}</ref> Reprocessed uranium is also safer in terms of nuclear proliferation potential.<ref>{{cite tech report|url=https://www.osti.gov/biblio/6743129-proliferation-resistant-nuclear-fuel-cycles-spiking-plutonium-sup-pu|title=Proliferation-resistant nuclear fuel cycles. [Spiking of plutonium with /sup 238/Pu]|publisher=Oak Ridge National Laboratory|year=1978|doi=10.2172/6743129|osti=6743129|last1=Campbell|first1=D. O.|last2=Gift|first2=E. H.|via=Office of Scientific and Technical Information}}</ref><ref>{{cite journal |last1=Fedorov |first1=M. I. |last2=Dyachenko |first2=A. I. |last3=Balagurov |first3=N. A. |last4=Artisyuk |first4=V. V. |year=2015 |title=Formation of proliferation-resistant nuclear fuel supplies based on reprocessed uranium for Russian nuclear technologies recipient countries |journal=Nuclear Energy and Technology |volume=1 |issue=2 |pages=111–116 |doi=10.1016/j.nucet.2015.11.023 |doi-access=free|bibcode=2015NEneT...1..111F }}</ref><ref>{{cite journal|title=Proliferation resistant plutonium: An updated analysis|journal=Nuclear Engineering and Design|volume=330|pages=297–302|doi=10.1016/j.nucengdes.2018.02.012|year=2018|last1=Lloyd|first1=Cody|last2=Goddard|first2=Braden|bibcode=2018NuEnD.330..297L }}</ref>

Reprocessing has the potential to recover up to 95% of the uranium and plutonium fuel in spent nuclear fuel, as well as reduce long-term radioactivity within the remaining waste. However, reprocessing has been politically controversial because of the potential for [[nuclear proliferation]] and varied perceptions of increasing the vulnerability to [[nuclear terrorism]].<ref name=berrytoll/><ref name=bas2011/> Reprocessing also leads to higher fuel cost compared to the once-through fuel cycle.<ref name=berrytoll>R. Stephen Berry and George S. Tolley, [http://franke.uchicago.edu/energy2013/group6.pdf Nuclear Fuel Reprocessing] {{Webarchive|url=https://web.archive.org/web/20170525170152/http://franke.uchicago.edu/energy2013/group6.pdf |date=2017-05-25 }}, The University of Chicago, 2013.</ref><ref name="bas2011">{{cite web |author=Feiveson |first=Harold |display-authors=etal |year=2011 |title=Managing nuclear spent fuel: Policy lessons from a 10-country study |url=http://www.thebulletin.org/web-edition/features/managing-nuclear-spent-fuel-policy-lessons-10-country-study |archive-url=https://web.archive.org/web/20120426011518/http://www.thebulletin.org/web-edition/features/managing-nuclear-spent-fuel-policy-lessons-10-country-study |archive-date=2012-04-26 |access-date=2016-07-18 |website=Bulletin of the Atomic Scientists}}</ref> While reprocessing reduces the volume of high-level waste, it does not reduce the [[fission product]]s that are the primary causes of residual heat generation and radioactivity for the first few centuries outside the reactor. Thus, reprocessed waste still requires an almost identical treatment for the initial first few hundred years.{{cn|date=August 2025}}

Reprocessing of civilian fuel from power reactors is currently done in France, the United Kingdom, Russia, Japan, and India. In the United States, spent nuclear fuel is currently not reprocessed.<ref name="WNA3" /> The [[La Hague reprocessing facility]] in France has operated commercially since 1976 and is responsible for half the world's reprocessing as of 2010.<ref>{{cite book|last=Kok|first=Kenneth D.|title=Nuclear Engineering Handbook|year=2010|publisher=CRC Press|page=332|isbn=978-1-4200-5391-3|url=https://books.google.com/books?id=EMy2OyUrqbUC&pg=PA332}}</ref> It produces MOX fuel from spent fuel derived from several countries. More than 32,000 tonnes of spent fuel had been reprocessed as of 2015, with the majority from France, 17% from Germany, and 9% from Japan.<ref>{{cite news |author=Jarry |first=Emmanuel |date=6 May 2015 |title=Crisis for Areva's plant as clients shun nuclear |url=http://www.mineweb.com/news/energy/crisis-for-arevas-plant-as-clients-shun-nuclear/ |archive-url=https://web.archive.org/web/20150723193237/http://www.mineweb.com/news/energy/crisis-for-arevas-plant-as-clients-shun-nuclear/ |archive-date=23 July 2015 |access-date=6 May 2015 |newspaper=Moneyweb |agency=Reuters}}</ref>

=== Breeding ===
[[File:Nuclear-Fuel.jpg|thumb|upright|[[Nuclear fuel]] assemblies being inspected before entering a [[pressurized water reactor]] in the United States]]
{{Main|Breeder reactor|Nuclear power proposed as renewable energy}}
Breeding is the process of converting non-fissile material into fissile material that can be used as nuclear fuel. The non-fissile material that can be used for this process is called [[fertile material]], and constitute the vast majority of current nuclear waste. This breeding process occurs naturally in [[breeder reactor]]s. As opposed to light water thermal-neutron reactors, which use uranium-235 (0.7% of all natural uranium), fast-neutron breeder reactors use uranium-238 (99.3% of all natural uranium) or thorium. A number of fuel cycles and breeder reactor combinations are considered to be sustainable or renewable sources of energy.<ref>{{cite journal|title=Future Scenarios for Fission Based Reactors|journal=Nuclear Physics A|volume=751|pages=429–441|bibcode=2005NuPhA.751..429D|last1=David|first1=S.|year=2005|doi=10.1016/j.nuclphysa.2005.02.014}}</ref><ref name="Brundtland">{{cite web|title=Chapter 7: Energy: Choices for Environment and Development|url=http://www.un-documents.net/ocf-07.htm|work=Our Common Future: Report of the World Commission on Environment and Development|first=Gro Harlem|last=Brundtland|location=Oslo|date=20 March 1987|access-date=27 March 2013|quote=Today's primary sources of energy are mainly non-renewable: natural gas, oil, coal, peat, and conventional nuclear power. There are also renewable sources, including wood, plants, dung, falling water, geothermal sources, solar, tidal, wind, and wave energy, as well as human and animal muscle-power. Nuclear reactors that produce their own fuel ('breeders') and eventually fusion reactors are also in this category|archive-date=21 January 2013|archive-url=https://web.archive.org/web/20130121175926/http://www.un-documents.net/ocf-07.htm|url-status=live}}</ref> In 2006 it was estimated that with seawater extraction, there was likely five billion years' worth of uranium resources for use in breeder reactors.<ref name="stanford-cohen">{{cite web |url=http://www-formal.stanford.edu/jmc/progress/cohen.html |title=Facts From Cohen and Others |access-date=2006-11-09 |publisher=Stanford |year=2006 |author=John McCarthy |author-link=John McCarthy (computer scientist) |website=Progress and its Sustainability |archive-url=https://web.archive.org/web/20070410165316/http://www-formal.stanford.edu/jmc/progress/cohen.html |archive-date=2007-04-10 }} Citing: {{cite journal |last1=Cohen |first1=Bernard L. |s2cid=119587950 |title=Breeder reactors: A renewable energy source |journal=American Journal of Physics |date=January 1983 |volume=51 |issue=1 |pages=75–76 |doi=10.1119/1.13440 |bibcode=1983AmJPh..51...75C }}</ref>

Breeder technology has been used in several reactors, but as of 2006, the high cost of reprocessing fuel safely requires uranium prices of more than US$200/kg before becoming justified economically.<ref name="wna-anpr">{{cite web |url=http://www.world-nuclear.org/info/inf08.html |title=Advanced Nuclear Power Reactors |access-date=2006-11-09 |publisher=World Nuclear Association |year=2006 |website=Information and Issue Briefs |archive-date=2010-06-15 |archive-url=https://web.archive.org/web/20100615004046/http://www.world-nuclear.org/info/inf08.html }}</ref> Breeder reactors are however being developed for their potential to burn all of the actinides (the most active and dangerous components) in the present inventory of nuclear waste, while also producing power and creating additional quantities of fuel for more reactors via the breeding process.<ref>{{cite web |url=http://www.worldenergy.org/documents/p001515.pdf |title=Synergy between Fast Reactors and Thermal Breeders for Safe, Clean, and Sustainable Nuclear Power |website=World Energy Council |archive-url=https://web.archive.org/web/20110110121245/http://worldenergy.org/documents/p001515.pdf |archive-date=2011-01-10 |access-date=2013-02-03 }}</ref><ref>{{cite web |author=Kessler |first=Rebecca |title=Are Fast-Breeder Reactors A Nuclear Power Panacea? by Fred Pearce: Yale Environment 360 |url=http://e360.yale.edu/feature/are_fast-breeder_reactors_a_nuclear_power_panacea/2557/ |url-status=live |archive-url=https://web.archive.org/web/20130605235042/http://e360.yale.edu/feature/are_fast-breeder_reactors_a_nuclear_power_panacea/2557/ |archive-date=2013-06-05 |access-date=2013-06-14 |publisher=E360.yale.edu}}</ref> As of 2017, there are two breeders producing commercial power, [[BN-600 reactor]] and the [[BN-800 reactor]], both in Russia.<ref name=WNAfast>{{cite web |title=Fast Neutron Reactors {{!}} FBR – World Nuclear Association |url=http://www.world-nuclear.org/information-library/current-and-future-generation/fast-neutron-reactors.aspx |website=www.world-nuclear.org |access-date=7 October 2018 |archive-date=23 December 2017 |archive-url=https://web.archive.org/web/20171223183305/http://world-nuclear.org/information-library/current-and-future-generation/fast-neutron-reactors.aspx |url-status=live }}</ref> The [[Phénix]] breeder reactor in France was powered down in 2009 after 36 years of operation.<ref name=WNAfast /> Both China and India are building breeder reactors. The Indian 500 MWe [[Prototype Fast Breeder Reactor]] is in the commissioning phase,<ref>{{cite news |title=Prototype fast breeder reactor to be commissioned in two months: IGCAR director |url=https://timesofindia.indiatimes.com/city/chennai/prototype-fast-breeder-reactor-to-be-commissioned-in-two-months-igcar-director/articleshow/61968967.cms |access-date=28 August 2018 |work=The Times of India |archive-date=15 September 2018 |archive-url=https://web.archive.org/web/20180915114720/https://timesofindia.indiatimes.com/city/chennai/prototype-fast-breeder-reactor-to-be-commissioned-in-two-months-igcar-director/articleshow/61968967.cms |url-status=live }}</ref> with plans to build more.<ref>{{cite news |url=http://www.hindustantimes.com/India-news/NewDelhi/India-s-breeder-reactor-to-be-commissioned-in-2013/Article1-814183.aspx |title=India's breeder reactor to be commissioned in 2013 |newspaper=Hindustan Times |access-date=2013-06-14 |archive-url=https://web.archive.org/web/20130426141852/http://www.hindustantimes.com/India-news/NewDelhi/India-s-breeder-reactor-to-be-commissioned-in-2013/Article1-814183.aspx |archive-date=2013-04-26 }}</ref>

Another alternative to fast-neutron breeders are thermal-neutron breeder reactors that use uranium-233 bred from [[thorium]] as fission fuel in the [[thorium fuel cycle]].<ref name="wna-thorium" /> Thorium is about 3.5 times more common than uranium in the Earth's crust, and has different geographic characteristics.<ref name="wna-thorium">{{cite web |url=http://www.world-nuclear.org/info/inf62.html |title=Thorium |access-date=2006-11-09 |publisher=World Nuclear Association |year=2006 |website=Information and Issue Briefs |archive-date=2013-02-16 |archive-url=https://web.archive.org/web/20130216102005/http://www.world-nuclear.org/info/inf62.html }}</ref> [[India's three-stage nuclear power programme]] features the use of a thorium fuel cycle in the third stage, as it has abundant thorium reserves but little uranium.<ref name="wna-thorium" />

== Decommissioning ==
{{Main|Nuclear decommissioning}}
Nuclear decommissioning is the process of dismantling a [[nuclear facility]] to the point that it no longer requires measures for radiation protection,<ref>{{Cite journal|date=2020-09-01|title=Developing policies for the end-of-life of energy infrastructure: Coming to terms with the challenges of decommissioning|journal=Energy Policy|language=en|volume=144|article-number=111677|doi=10.1016/j.enpol.2020.111677|issn=0301-4215|doi-access=free|last1=Invernizzi|first1=Diletta Colette|last2=Locatelli|first2=Giorgio|last3=Velenturf|first3=Anne|last4=Love|first4=Peter ED.|last5=Purnell|first5=Phil|last6=Brookes|first6=Naomi J.|bibcode=2020EnPol.14411677I |hdl=11311/1204791|hdl-access=free}}</ref> returning the facility and its parts to a safe enough level to be entrusted for other uses.<ref name="iaea_decommissioning">{{cite web |title=Decommissioning of nuclear installations |url=https://www.iaea.org/topics/decommissioning |website=www.iaea.org |access-date=19 April 2021 |language=en |date=17 October 2016 |archive-date=21 April 2021 |archive-url=https://web.archive.org/web/20210421073553/https://www.iaea.org/topics/decommissioning |url-status=live }}</ref> Due to the presence of radioactive materials, nuclear decommissioning presents technical and economic challenges.<ref>{{Cite journal|last1=Invernizzi|first1=Diletta Colette|last2=Locatelli|first2=Giorgio|last3=Brookes|first3=Naomi J.|date=2017-08-01|title=How benchmarking can support the selection, planning and delivery of nuclear decommissioning projects|journal=Progress in Nuclear Energy|volume=99|pages=155–164|doi=10.1016/j.pnucene.2017.05.002|bibcode=2017PNuE...99..155I |url=http://eprints.whiterose.ac.uk/117185/1/Copy%20to%20deposit.pdf|access-date=2021-04-19|archive-date=2021-06-14|archive-url=https://web.archive.org/web/20210614050809/https://eprints.whiterose.ac.uk/117185/1/Copy%20to%20deposit.pdf|url-status=live}}</ref> The costs of decommissioning are generally spread over the lifetime of a facility and saved in a decommissioning fund.<ref>{{cite web |url=https://www.nrc.gov/reading-rm/doc-collections/fact-sheets/decommissioning.html |title=Backgrounder on Decommissioning Nuclear Power Plants |publisher=United States Nuclear Regulatory Commission |access-date=27 August 2021 |quote=Before a nuclear power plant begins operations, the licensee must establish or obtain a financial mechanism – such as a trust fund or a guarantee from its parent company – to ensure there will be sufficient money to pay for the ultimate decommissioning of the facility |archive-date=3 May 2021 |archive-url=https://web.archive.org/web/20210503213818/http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/decommissioning.html |url-status=live }}</ref>

== Production ==
{{Further|Nuclear power by country|List of nuclear reactors}}
<!-- Deleted image removed: [[File:Share of electricity production (from nuclear).png|thumb|right|upright=1.6|Share of electricity production from nuclear, 2024<ref>{{cite web |title=Share of electricity production from nuclear |url=https://ourworldindata.org/grapher/share-electricity-nuclear |website=Our World in Data |access-date=27 June 2025}}</ref>]] -->
[[File:Nuclear power station.svg|thumb|right|upright=1.6|The status of nuclear power globally (click for legend)]]
{{Latest pie chart of world power by source}}
Civilian nuclear power supplied 2,602 [[terawatt hour]]s (TWh) of electricity in 2023, equivalent to about 9% of [[global electricity generation]],<ref name=PerformanceReport /> and was the second largest [[low-carbon power]] source after [[hydroelectricity]].<ref name="IEA2019">{{Cite web|url=https://www.iea.org/newsroom/news/2019/may/steep-decline-in-nuclear-power-would-threaten-energy-security-and-climate-goals.html|title=Steep decline in nuclear power would threaten energy security and climate goals|publisher=International Energy Agency|date=2019-05-28|access-date=2019-07-08|archive-date=2019-10-12|archive-url=https://web.archive.org/web/20191012154515/https://www.iea.org/newsroom/news/2019/may/steep-decline-in-nuclear-power-would-threaten-energy-security-and-climate-goals.html|url-status=live}}</ref> Nuclear power's contribution to global energy production was about 4% in 2023. This is a little more than wind power, which provided 3.5% of global energy in 2023.<ref>{{Cite web|url=https://ourworldindata.org/grapher/energy-consumption-by-source-and-country|title=Energy consumption by source, World|publisher=Our World in Data|access-date=2024-11-10}}</ref> Nuclear power's share of global electricity production has fallen from 16.5% in 1997, in large part because the economics of nuclear power have become more difficult.<ref name=ft-20180903>{{cite news |url=https://www.ft.com/content/fa6ca7ac-ab9a-11e8-89a1-e5de165fa619 |archive-url=https://ghostarchive.org/archive/20221210/https://www.ft.com/content/fa6ca7ac-ab9a-11e8-89a1-e5de165fa619 |archive-date=2022-12-10 |url-access=subscription |url-status=live |title=The challenge for nuclear is to recover its competitive edge |last=Butler |first=Nick |newspaper=Financial Times |date=3 September 2018 |access-date=9 September 2018}}</ref>

{{As of|2024|11|post=,}} there are [[List of nuclear reactors|415 civilian fission reactors in the world]], with a combined electrical capacity of 374 [[gigawatt]] (GW).<ref name=":3" /> There are also 66 nuclear power reactors under construction and 87 reactors planned, with a combined capacity of 72{{nbsp}}GW and 84{{nbsp}}GW, respectively.<ref name="WNA">{{cite web|title=World Nuclear Power Reactors & Uranium Requirements|publisher=World Nuclear Association|url=https://www.world-nuclear.org/information-library/facts-and-figures/world-nuclear-power-reactors-and-uranium-requireme.aspx|access-date=2024-11-10}}</ref> The United States has the largest fleet of nuclear reactors, generating over 800{{nbsp}}TWh per year with an average [[capacity factor]] of 92%.<ref name=":2">{{Cite web|title=What's the Lifespan for a Nuclear Reactor? Much Longer Than You Might Think|url=https://www.energy.gov/ne/articles/whats-lifespan-nuclear-reactor-much-longer-you-might-think|access-date=2020-06-09|website=Energy.gov|language=en|archive-date=2020-06-09|archive-url=https://web.archive.org/web/20200609230342/https://www.energy.gov/ne/articles/whats-lifespan-nuclear-reactor-much-longer-you-might-think|url-status=live}}</ref> Most reactors under construction are [[generation III reactor]]s in Asia.<ref>{{cite web |url=https://pris.iaea.org/PRIS/WorldStatistics/UnderConstructionReactorsByCountry.aspx |title=Under Construction Reactors |publisher=International Atomic Energy Agency |access-date=2019-12-15 |archive-date=2018-11-22 |archive-url=https://web.archive.org/web/20181122202635/https://pris.iaea.org/PRIS/WorldStatistics/UnderConstructionReactorsByCountry.aspx |url-status=live }}</ref>

Regional differences in the use of nuclear power are large. The United States produces the most nuclear energy in the world, with nuclear power providing 19% of the electricity it consumes, while France produces the highest percentage of its electrical energy from nuclear reactors{{mdash}}65% in 2023.<ref name=":0">{{Cite web|url=https://pris.iaea.org/PRIS/WorldStatistics/NuclearShareofElectricityGeneration.aspx|title=Nuclear Share of Electricity Generation in 2023|website=Power Reactor Information System|publisher=International Atomic Energy Agency|access-date=2024-11-11}}</ref> In the [[European Union]], nuclear power provides 22% of the electricity as of 2022.<ref name=WNA-EU>{{Cite web |title=Nuclear Power in the European Union |url=https://world-nuclear.org/information-library/country-profiles/others/european-union |date=2024-08-13 |access-date=2024-11-11 |publisher=World Nuclear Association}}</ref>
Nuclear power is the single largest low-carbon electricity source in the United States,<ref name=issues>{{Cite web|url=https://issues.org/apt-3/|archive-url=https://web.archive.org/web/20130927013232/http://www.issues.org/23.3/apt.html  |title=Promoting Low-Carbon Electricity Production|first1=Jay|last1=Apt|first2=David W.|last2=Keith|first3=M. Granger|last3=Morgan|date=January 1, 1970|archive-date=September 27, 2013}}</ref> and accounts for about half of the European Union's low-carbon electricity.<ref name=WNA-EU /> [[Nuclear energy policy]] differs among European Union countries, and some, such as Austria, [[Estonia]], Ireland and [[Nuclear power in Italy|Italy]], have no active nuclear power stations.<ref>{{cite web |title=PRIS - Country Statistics |url=https://pris.iaea.org/PRIS/CountryStatistics/CountryStatisticsLandingPage.aspx |website=pris.iaea.org |publisher=International Atomic Energy Agency |access-date=5 September 2025}}</ref>

In addition, there were approximately 140 naval vessels using [[nuclear propulsion]] in operation, powered by about 180 reactors.<ref>{{cite web |url=http://www.engineersgarage.com/articles/nuclear-power-plants?page=2 |title=What is Nuclear Power Plant – How Nuclear Power Plants work &#124; What is Nuclear Power Reactor – Types of Nuclear Power Reactors |publisher=EngineersGarage |access-date=2013-06-14 |archive-url=https://web.archive.org/web/20131004215527/http://www.engineersgarage.com/articles/nuclear-power-plants?page=2 |archive-date=2013-10-04 }}</ref><ref>{{cite web |author=Ragheb |first=Magdi |title=Naval Nuclear Propulsion |url=http://www.ewp.rpi.edu/hartford/~ernesto/F2010/EP2/Materials4Students/Misiaszek/NuclearMarinePropulsion.pdf |archive-url=https://web.archive.org/web/20150226055625/http://www.ewp.rpi.edu/hartford/~ernesto/F2010/EP2/Materials4Students/Misiaszek/NuclearMarinePropulsion.pdf |archive-date=2015-02-26 |access-date=2015-06-04 |quote=As of 2001, about 235 naval reactors had been built.}}</ref> These include military and some civilian ships, such as [[nuclear-powered icebreaker]]s.<ref>{{Cite news | url=http://www.bellona.org/english_import_area/international/russia/civilian_nuclear_vessels/icebreakers/30131 |title=Nuclear Icebreaker Lenin |publisher=Bellona |date=2003-06-20 |access-date=2007-11-01 |archive-url= https://web.archive.org/web/20071015031630/http://www.bellona.org/english_import_area/international/russia/civilian_nuclear_vessels/icebreakers/30131 |archive-date=October 15, 2007 }}</ref>

International research is continuing into additional uses of process heat such as [[hydrogen production]] (in support of a [[hydrogen economy]]), for [[desalination|desalinating]] sea water, and for use in [[district heating]] systems.<ref>{{cite book |title=Non-electric Applications of Nuclear Power: Seawater Desalination, Hydrogen Production and other Industrial Applications |date=2007 |publisher=International Atomic Energy Agency |isbn=978-92-0-108808-6 |url=https://www.iaea.org/publications/7979/non-electric-applications-of-nuclear-power-seawater-desalination-hydrogen-production-and-other-industrial-applications |access-date=21 August 2018 |archive-date=27 March 2019 |archive-url=https://web.archive.org/web/20190327040900/https://www.iaea.org/publications/7979/non-electric-applications-of-nuclear-power-seawater-desalination-hydrogen-production-and-other-industrial-applications |url-status=live }}</ref>

== Economics ==
[[File:3-Learning-curves-for-electricity-prices.png|thumb|upright=2|A comparison of [[levelized cost of energy]] (LCOE) over time for nuclear power and other sources. 
While wind turbines and solar panels can be mass-produced and thus enjoy [[learning curve effects]], nuclear are almost always one-of-a-kind projects due to the limited number of reactors being built. 
The source of this chart, ''[[Our World in Data]]'' notes that the costs presented here is the global ''average'', and these costs were driven up by 2 projects in the United States. The organization recognises that the [[median]] cost of the most exported and produced nuclear energy facility in the 2010s the South Korean [[APR1400]], remained "constant", including in export.<ref>{{cite journal | url=https://ourworldindata.org/cheap-renewables-growth | title=Why did renewables become so cheap so fast? | journal=Our World in Data | date=1 December 2020 | last1=Roser | first1=Max }}</ref>]]
{{Main|Economics of nuclear power plants|List of companies in the nuclear sector|cost of electricity by source}}
The economics of new nuclear power plants is a controversial subject. Nuclear power plants typically have high capital costs for building the plant. For this reason, comparison with other power generation methods is strongly dependent on assumptions about construction timescales and capital financing for nuclear plants. 
Because of this strong dependency, the final cost of electricity from nuclear power is strongly dependent on the [[cost of capital]].<ref>{{cite web |title=Economics of Nuclear Power - World Nuclear Association |url=https://world-nuclear.org/information-library/economic-aspects/economics-of-nuclear-power |website=world-nuclear.org |publisher=World Nuclear Association |access-date=1 September 2025}}</ref>

Analysis of the economics of nuclear power must also take into account who bears the risks of future uncertainties. As of 2010, all operating nuclear power plants have been developed by state-owned or [[Regulated market|regulated]] [[electric utility]] monopolies.<ref name="ft-20100912">{{cite news |author=Crooks |first=Ed |date=2010-09-12 |title=Nuclear: New dawn now seems limited to the east |url=https://www.ft.com/content/ad15fcfe-bc71-11df-a42b-00144feab49a |url-access=subscription |archive-url=https://ghostarchive.org/archive/20221210/http://www.ft.com/cms/s/0/ad15fcfe-bc71-11df-a42b-00144feab49a.html |archive-date=2022-12-10 |access-date=2010-09-12 |newspaper=Financial Times |location=London, England}}</ref> Many countries have since liberalized the [[electricity market]] where these risks, and the risk of cheaper competitors emerging before capital costs are recovered, are borne by plant suppliers and operators rather than consumers, which leads to a significantly different evaluation of the economics of new nuclear power plants.<ref name=MIT-2003>{{Cite book |url=http://web.mit.edu/nuclearpower/ |title=The Future of Nuclear Power |publisher=[[Massachusetts Institute of Technology]] |year=2003 |isbn=978-0-615-12420-9 |access-date=2006-11-10 |archive-date=2017-05-18 |archive-url=https://web.archive.org/web/20170518215841/http://web.mit.edu/nuclearpower/ |url-status=live }}</ref>

The [[levelized cost of electricity]] (LCOE) from a new nuclear power plant is estimated to be 69{{nbsp}}USD/MWh, according to an analysis by the [[International Energy Agency]] and the [[OECD]] [[Nuclear Energy Agency]]. This represents the median cost estimate for an nth-of-a-kind nuclear power plant to be completed in 2025, at a [[Discounting|discount rate]] of 7%. Nuclear power was found to be the least-cost option among [[Dispatchable generation|dispatchable technologies]].<ref name="IEA_LCOE_2020"/> [[Variable renewable energy|Variable renewables]] can generate cheaper electricity: the median cost of onshore wind power was estimated to be 50{{nbsp}}USD/MWh, and utility-scale solar power 56{{nbsp}}USD/MWh.<ref name="IEA_LCOE_2020"/> However, these sources are not directly comparable to nuclear power as they are not [[dispatchable generation|dispatchable]].
Measures to [[mitigate global warming]], such as a [[carbon tax]] or [[carbon emissions trading]], may favor the economics of nuclear power.<ref>{{cite book |title=Update of the MIT 2003 Future of Nuclear Power |date=2009 |publisher=Massachusetts Institute of Technology |url=http://web.mit.edu/nuclearpower/pdf/nuclearpower-update2009.pdf |access-date=21 August 2018 |archive-date=3 February 2023 |archive-url=https://web.archive.org/web/20230203232427/http://web.mit.edu/nuclearpower/pdf/nuclearpower-update2009.pdf |url-status=live }}</ref><ref>{{cite news |title=Splitting the cost |url=https://www.economist.com/britain/2009/11/12/splitting-the-cost |access-date=21 August 2018 |newspaper=The Economist |date=12 November 2009 |language=en |archive-date=21 August 2018 |archive-url=https://web.archive.org/web/20180821191849/https://www.economist.com/britain/2009/11/12/splitting-the-cost |url-status=live }}</ref> 
At the assumed CO<sub>2</sub> emission cost of 30{{nbsp}}USD/ton, power from coal (88{{nbsp}}USD/MWh) and gas (71{{nbsp}}USD/MWh) is more expensive than low-carbon technologies. Electricity from long-term operation of nuclear power plants by lifetime extension was found to be the least-cost option, at 32{{nbsp}}USD/MWh.<ref name="IEA_LCOE_2020">{{cite web |title=Projected Costs of Generating Electricity 2020 |date=9 December 2020 |url=https://www.iea.org/reports/projected-costs-of-generating-electricity-2020 |publisher=International Energy Agency & OECD Nuclear Energy Agency |access-date=12 December 2020 |archive-date=2 April 2022 |archive-url=https://web.archive.org/web/20220402003026/https://www.iea.org/reports/projected-costs-of-generating-electricity-2020 |url-status=live }}</ref>

The high cost of construction is one of the biggest challenges for nuclear power plants. Nuclear power cost trends show large disparity by nation, design, build rate and the establishment of familiarity in expertise. The only two nations for which data is available that saw cost decreases in the 2000s were India and South Korea.<ref name=Lovering2016>{{cite journal |doi=10.1016/j.enpol.2016.01.011 |title=Historical construction costs of global nuclear power reactors |journal=Energy Policy |volume=91 |pages=371–382 |year=2016 |last1=Lovering |first1=Jessica R. |author-link1=Jessica Lovering |last2=Yip |first2=Arthur |last3=Nordhaus |first3=Ted |author-link3=Ted Nordhaus |doi-access=free |bibcode=2016EnPol..91..371L }}</ref>
New [[small modular reactors]], such as those developed by [[NuScale Power]], are aimed at reducing the investment costs for new construction by making the reactors smaller and modular, so that they can be built in a factory.{{cn|date=August 2025}}

Certain designs had considerable early positive economics, such as the [[CANDU]], which realized a much higher [[capacity factor]] and reliability when compared to generation II light water reactors up to the 1990s.<ref>{{Cite web |title=The Canadian Nuclear FAQ – Section A: CANDU Technology |url=http://www.nuclearfaq.ca/cnf_sectionA.htm |archive-url=https://web.archive.org/web/20131101054647/http://nuclearfaq.ca/cnf_sectionA.htm |archive-date=2013-11-01 |access-date=2019-08-05}}</ref>
Due to the on-line refueling reactor design, [[PHWR]]s (of which the CANDU design is a part) continue to hold many world record positions for longest continual electricity generation, often over 800 days.<ref>{{Cite web | url=https://www.world-nuclear-news.org/Articles/Indian-reactor-breaks-operating-record | title=Indian reactor breaks operating record | work=World Nuclear News | date=25 October 2018 | access-date=4 August 2019 | archive-date=4 August 2019 | archive-url=https://web.archive.org/web/20190804075915/https://www.world-nuclear-news.org/Articles/Indian-reactor-breaks-operating-record | url-status=live }}</ref> The specific record as of 2019 is held by a PHWR at [[Kaiga Atomic Power Station]], generating electricity continuously for 962 days.<ref>{{cite web |title=Indian-Designed Nuclear Reactor Breaks Record for Continuous Operation |url=https://www.powermag.com/indian-designed-nuclear-reactor-breaks-record-for-continuous-operation/ |website=POWER Magazine |access-date=28 March 2019 |date=1 February 2019 |archive-date=28 March 2019 |archive-url=https://web.archive.org/web/20190328211427/https://www.powermag.com/indian-designed-nuclear-reactor-breaks-record-for-continuous-operation/ |url-status=live }}</ref>

Nuclear power plants, though capable of some grid-[[load following]], are typically run as much as possible to keep the cost of the generated electrical energy as low as possible, supplying mostly [[base-load]] electricity.<ref>{{cite web |url=https://www.oecd-nea.org/nea-news/2011/29-2/nea-news-29-2-load-following-e.pdf |title=Load-following with nuclear power plants |author=A. Lokhov |access-date=2016-03-12 |archive-date=2016-02-22 |archive-url=https://web.archive.org/web/20160222051312/http://www.oecd-nea.org/nea-news/2011/29-2/nea-news-29-2-load-following-e.pdf |url-status=live }}</ref> 

In some cases, Governments were found to force "consumers to pay upfront for potential cost overruns"<ref name="mil1"/> or subsidize uneconomic nuclear energy<ref>{{cite news |last1=Gardner |first1=Timothy |title=Illinois approves $700 million in subsidies to Exelon, prevents nuclear plant closures |url=https://www.reuters.com/world/us/illinois-senate-close-providing-lifeline-3-nuclear-power-plants-2021-09-13/ |access-date=28 November 2021 |work=Reuters |date=13 September 2021 |language=en |archive-date=3 November 2021 |archive-url=https://web.archive.org/web/20211103015537/https://www.reuters.com/world/us/illinois-senate-close-providing-lifeline-3-nuclear-power-plants-2021-09-13/ |url-status=live }}</ref> or be required to do so.<ref name="francere">{{cite news |title=Building new nuclear plants in France uneconomical -environment agency |url=https://www.reuters.com/article/france-nuclearpower/building-new-nuclear-plants-in-france-uneconomical-environment-agency-idUSL8N1YF5HC |access-date=25 November 2021 |work=Reuters |date=10 December 2018 |language=en |archive-date=25 November 2021 |archive-url=https://web.archive.org/web/20211125145227/https://www.reuters.com/article/france-nuclearpower/building-new-nuclear-plants-in-france-uneconomical-environment-agency-idUSL8N1YF5HC |url-status=live }}</ref> Nuclear operators are liable to pay for the waste management in the European Union.<ref name="euwastecosts">{{cite news |title=Europe faces €253bn nuclear waste bill |url=https://www.theguardian.com/environment/2016/apr/04/europe-faces-253bn-nuclear-waste-bill |access-date=24 November 2021 |work=The Guardian |date=4 April 2016 |language=en}}</ref> In the U.S., the Congress reportedly decided 40 years ago that the nation, and not private companies, would be responsible for storing radioactive waste with taxpayers paying for the costs.<ref>{{cite news |last1=Wade |first1=Will |title=Americans are paying more than ever to store deadly nuclear waste |url=https://www.latimes.com/business/la-fi-radioactive-nuclear-waste-storage-20190614-story.html |access-date=28 November 2021 |work=Los Angeles Times |date=14 June 2019 |archive-date=28 November 2021 |archive-url=https://web.archive.org/web/20211128121638/https://www.latimes.com/business/la-fi-radioactive-nuclear-waste-storage-20190614-story.html |url-status=live }}</ref> The World Nuclear Waste Report 2019 found that "even in countries in which the polluter-pays-principle is a legal requirement, it is applied incompletely" and notes the case of the German [[Asse II mine|Asse II deep geological disposal facility]], where the retrieval of large amounts of waste has to be paid for by taxpayers.<ref>{{cite web |title=The World Nuclear Waste Report 2019 |url=https://www.boell.de/sites/default/files/2019-11/World_Nuclear_Waste_Report_2019_summary.pdf |access-date=28 November 2021 |archive-date=29 November 2021 |archive-url=https://web.archive.org/web/20211129140256/https://www.boell.de/sites/default/files/2019-11/World_Nuclear_Waste_Report_2019_summary.pdf |url-status=live }}</ref> Similarly, other forms of energy, including fossil fuels and renewables, have a portion of their costs covered by governments.<ref>{{cite web |title=Energy Subsidies |url=https://world-nuclear.org/information-library/economic-aspects/energy-subsidies.aspx
 |archive-url=https://web.archive.org/web/20211204180955/https://world-nuclear.org/information-library/economic-aspects/energy-subsidies.aspx |archive-date=2021-12-04 |publisher=World Nuclear Association |date=2018}}</ref>

== Use in space ==
[[File:Msl-MMRTG.jpg|thumb|The [[multi-mission radioisotope thermoelectric generator]] (MMRTG), used in several space missions such as the [[Curiosity (rover)|''Curiosity'' Mars rover]] ]]
{{Main|Nuclear power in space}}
The most common use of nuclear power in space is the use of [[radioisotope thermoelectric generator]]s, which use [[radioactive decay]] to generate power. These power generators are relatively small scale (few kW), and they are mostly used to power [[space mission]]s and experiments for long periods where solar power is not available in sufficient quantity, such as in the ''[[Voyager 2]]'' space probe.<ref name=WNA_space/> A few space vehicles have been launched using [[nuclear reactor]]s: 34 reactors belong to the Soviet [[RORSAT]] series and one was the American [[SNAP-10A]].<ref name="WNA_space">{{cite web |title=Nuclear Reactors for Space – World Nuclear Association |url=https://world-nuclear.org/information-library/non-power-nuclear-applications/transport/nuclear-reactors-for-space.aspx |url-status=live |archive-url=https://web.archive.org/web/20210417023904/https://world-nuclear.org/information-library/non-power-nuclear-applications/transport/nuclear-reactors-for-space.aspx |archive-date=17 April 2021 |access-date=17 April 2021 |website=world-nuclear.org}}</ref>

Both [[Nuclear fission|fission]] and fusion appear promising for [[space propulsion]] applications, generating higher mission velocities with less [[reaction mass]].<ref name=WNA_space/><ref>{{cite news |last1=Patel |first1=Prachi |title=Nuclear-Powered Rockets Get a Second Look for Travel to Mars |url=https://spectrum.ieee.org/nuclear-powered-rockets-get-a-second-look-for-travel-to-mars |access-date=17 April 2021 |work=IEEE Spectrum |language=en |archive-date=10 April 2021 |archive-url=https://web.archive.org/web/20210410191445/https://spectrum.ieee.org/aerospace/space-flight/nuclear-powered-rockets-get-a-second-look-for-travel-to-mars |url-status=live }}</ref>

== Safety ==
{{See also|Nuclear safety and security|Nuclear reactor safety system}}
[[File:Energy Production Death Rates per TWh.png|thumb|upright=1.5|Death rates per unit of electricity production for different energy sources]]
Nuclear power plants have three unique characteristics that affect their safety, as compared to other power plants. Firstly, intensely [[radioactive material]]s are present in a nuclear reactor. Their release to the environment could be hazardous. Secondly, the [[fission product]]s, which make up most of the intensely radioactive substances in the reactor, continue to generate a significant amount of [[decay heat]] even after the fission [[Nuclear chain reaction|chain reaction]] has stopped. If the heat cannot be removed from the reactor, the fuel rods may overheat and release radioactive materials. Thirdly, a [[criticality accident]] (a rapid increase of the reactor power) is possible in certain reactor designs if the chain reaction cannot be controlled. These three characteristics have to be taken into account when designing nuclear reactors.<ref name="IAEAsafety">{{Cite web |last=Deitrich |first=L. W. |title=Basic principles of nuclear safety |url=https://ansn.iaea.org/ansn.org/Common/Documents/apmd/asia251p4.pdf |url-status=live |archive-url=https://web.archive.org/web/20181119011032/https://ansn.iaea.org/ansn.org/Common/Documents/apmd/asia251p4.pdf |archive-date=2018-11-19 |access-date=2018-11-18 |publisher=International Atomic Energy Agency}}</ref>

All modern reactors are designed so that an uncontrolled increase of the reactor power is prevented by natural feedback mechanisms, a concept known as negative [[void coefficient]] of reactivity. If the temperature or the amount of steam in the reactor increases, the fission rate inherently decreases. The chain reaction can also be manually stopped by inserting [[control rod]]s into the reactor core. [[Emergency core cooling system]]s (ECCS) can remove the decay heat from the reactor if normal cooling systems fail.<ref>{{Cite web|url=https://www.nrc.gov/reading-rm/basic-ref/glossary/emergency-core-cooling-systems-eccs.html|title=Emergency core cooling systems (ECCS)|date=2018-07-06|publisher=United States Nuclear Regulatory Commission|access-date=2018-12-10|archive-date=2021-04-29|archive-url=https://web.archive.org/web/20210429133036/https://www.nrc.gov/reading-rm/basic-ref/glossary/emergency-core-cooling-systems-eccs.html|url-status=live}}</ref> If the ECCS fails, multiple physical barriers limit the release of radioactive materials to the environment even in the case of an accident. The last physical barrier is the large [[containment building]].<ref name="IAEAsafety" />

With a death rate of 0.03 per [[TWh]], nuclear power is the second safest energy source per unit of energy generated, after solar power, in terms of mortality when the historical track-record is considered.<ref>{{Cite web|title=What are the safest and cleanest sources of energy?|url=https://ourworldindata.org/safest-sources-of-energy|website=Our World in Data|date=10 February 2020 |access-date=2023-11-15|archive-date=2020-11-29|archive-url=https://web.archive.org/web/20201129205209/https://ourworldindata.org/safest-sources-of-energy|url-status=live |last1=Ritchie |first1=Hannah }}</ref> Energy produced by coal, petroleum, natural gas and [[hydropower]] has caused more deaths per unit of energy generated due to [[air pollution]] and [[energy accidents]]. This is found when comparing the immediate deaths from other energy sources to both the immediate and the latent, or predicted, indirect cancer deaths from nuclear energy accidents.<ref name="without the hot air">{{cite web |url= http://www.inference.phy.cam.ac.uk/withouthotair/c24/page_168.shtml |title= Dr. MacKay ''Sustainable Energy without the hot air'' |website= Data from studies by the [[Paul Scherrer Institute]] including non EU data |page= 168 |access-date= 2012-09-15 |archive-date= 2012-09-02 |archive-url= https://web.archive.org/web/20120902001529/http://www.inference.phy.cam.ac.uk/withouthotair/c24/page_168.shtml |url-status= live }}</ref><ref name="theage2006">{{cite news |author=Nicholson |first=Brendan |date=2006-06-05 |title=Nuclear power 'cheaper, safer' than coal and gas |url=http://www.theage.com.au/news/national/nuclear-power-cheaper-safer-than-coal-and-gas/2006/06/04/1149359609052.html |url-status=live |archive-url=https://web.archive.org/web/20080208123433/http://www.theage.com.au/news/national/nuclear-power-cheaper-safer-than-coal-and-gas/2006/06/04/1149359609052.html |archive-date=2008-02-08 |access-date=2008-01-18 |newspaper=[[The Age]] |location=Melbourne}}</ref> When the direct and indirect fatalities (including fatalities resulting from the mining and air pollution) from nuclear power and fossil fuels are compared,<ref name="MarkandyaWilkinson2007">{{cite journal | doi = 10.1016/S0140-6736(07)61253-7 | last1 = Markandya | first1 = A. | last2 = Wilkinson | first2 = P. | title = Electricity generation and health | journal = Lancet | volume = 370 | issue = 9591 | pages = 979–990 | year = 2007 | pmid = 17876910| s2cid = 25504602 |quote=Nuclear power has lower electricity related health risks than Coal, Oil, & gas. ...the health burdens are appreciably smaller for generation from natural gas, and lower still for nuclear power. This study includes the latent or indirect fatalities, for example those caused by the inhalation of fossil fuel created particulate matter, smog induced cardiopulmonary events, black lung etc. in its comparison.}}</ref> the use of nuclear power has been calculated to have prevented about 1.84 million deaths from air pollution between 1971 and 2009, by reducing the proportion of energy that would otherwise have been generated by fossil fuels.<ref name="autogenerated1">{{cite web |url=http://cen.acs.org/articles/91/web/2013/04/Nuclear-Power-Prevents-Deaths-Causes.html |title=Nuclear Power Prevents More Deaths Than It Causes &#124; Chemical & Engineering News |publisher=Cen.acs.org |access-date=2014-01-24 |archive-date=2014-03-01 |archive-url=https://web.archive.org/web/20140301145251/http://cen.acs.org/articles/91/web/2013/04/Nuclear-Power-Prevents-Deaths-Causes.html |url-status=live }}</ref><ref name="Kharecha Pushker A 2013 4889–4895">{{cite journal | last1=Kharecha | first1=Pushker A. | last2=Hansen | first2=James E. |title=Prevented Mortality and Greenhouse Gas Emissions from Historical and Projected Nuclear Power |doi=10.1021/es3051197 |pmid=23495839 |bibcode = 2013EnST...47.4889K |volume=47 |issue=9 |journal=Environmental Science & Technology |pages=4889–4895 |year=2013 |doi-access=free |hdl=2060/20140017100 |hdl-access=free }}</ref> Following the 2011 Fukushima nuclear disaster, it has been estimated that if Japan had never adopted nuclear power, accidents and pollution from coal or gas plants would have caused more lost years of life.<ref>{{cite journal |author=Normile |first=Dennis |date=2012-07-27 |title=Is Nuclear Power Good for You? |url=http://news.sciencemag.org/scienceinsider/2012/07/is-nuclear-power-good-for-you.html |journal=Science |volume=337 |issue=6093 |page=395 |doi=10.1126/science.337.6093.395-b |archive-url=https://web.archive.org/web/20130301082701/http://news.sciencemag.org/scienceinsider/2012/07/is-nuclear-power-good-for-you.html |archive-date=2013-03-01|url-access=subscription }}</ref>

Serious impacts of nuclear accidents are often not directly attributable to radiation exposure, but rather social and psychological effects. Evacuation and long-term displacement of affected populations created problems for many people, especially the elderly and hospital patients.<ref>{{cite journal |last1=Hasegawa |first1=Arifumi |last2=Tanigawa |first2=Koichi |last3=Ohtsuru |first3=Akira |last4=Yabe |first4=Hirooki |last5=Maeda |first5=Masaharu |last6=Shigemura |first6=Jun |last7=Ohira |first7=Tetsuya |last8=Tominaga |first8=Takako |last9=Akashi |first9=Makoto |last10=Hirohashi |first10=Nobuyuki |last11=Ishikawa |first11=Tetsuo |last12=Kamiya |first12=Kenji |last13=Shibuya |first13=Kenji |last14=Yamashita |first14=Shunichi |last15=Chhem |first15=Rethy K |title=Health effects of radiation and other health problems in the aftermath of nuclear accidents, with an emphasis on Fukushima |journal=The Lancet |date=August 2015 |volume=386 |issue=9992 |pages=479–488 |doi=10.1016/S0140-6736(15)61106-0 |pmid=26251393 |s2cid=19289052 |url=http://ir.fmu.ac.jp/dspace/bitstream/123456789/1575/1/Lancet_386_p479.pdf |access-date=2021-08-05 |archive-date=2021-08-28 |archive-url=https://web.archive.org/web/20210828051002/https://ir.fmu.ac.jp/dspace/bitstream/123456789/1575/1/Lancet_386_p479.pdf |url-status=live }}</ref> Forced evacuation from a nuclear accident may lead to social isolation, anxiety, depression, psychosomatic medical problems, reckless behavior, and suicide. A comprehensive 2005 study on the aftermath of the Chernobyl disaster concluded that the mental health impact is the largest public health problem caused by the accident.<ref name="riv12">{{cite news |author=Revkin |first=Andrew C. |author-link=Andrew C. Revkin |date=2012-03-10 |title=Nuclear Risk and Fear, from Hiroshima to Fukushima |url=http://dotearth.blogs.nytimes.com/2012/03/10/nuclear-risk-and-fear-from-hiroshima-to-fukushima/ |url-status=live |archive-url=https://web.archive.org/web/20150905200055/http://dotearth.blogs.nytimes.com/2012/03/10/nuclear-risk-and-fear-from-hiroshima-to-fukushima/ |archive-date=2015-09-05 |access-date=2013-07-08 |newspaper=The New York Times}}</ref> [[Frank N. von Hippel]], an American scientist, commented that a disproportionate fear of ionizing radiation ([[radiophobia]]) could have long-term psychological effects on the population of contaminated areas following the Fukushima disaster.<ref name="Frank N. von Hippel 27–36">{{cite journal |author=von Hippel |first=Frank N. |date=September–October 2011 |title=The radiological and psychological consequences of the Fukushima Daiichi accident |url=http://bos.sagepub.com/content/67/5/27.full |url-status=live |journal=Bulletin of the Atomic Scientists |volume=67 |issue=5 |pages=27–36 |bibcode=2011BuAtS..67e..27V |doi=10.1177/0096340211421588 |s2cid=218769799 |archive-url=https://web.archive.org/web/20120113090511/http://bos.sagepub.com/content/67/5/27.full |archive-date=2012-01-13 |access-date=2013-07-08|url-access=subscription }}</ref>

=== Accidents ===
[[File:Fukushima I by Digital Globe crop.jpg|thumb|upright=1.2|Following the 2011 [[Fukushima Daiichi nuclear disaster]], the world's worst [[nuclear accident]] since 1986, 50,000 households were displaced after [[radiation]] leaked into the air, soil and sea.<ref>{{cite news |last1=Yamazaki |first1=Tomoko |last2=Ozasa |first2=Shunichi |name-list-style=amp |date=2011-06-27 |title=Fukushima Retiree Leads Anti-Nuclear Shareholders at Tepco Annual Meeting |url=https://www.bloomberg.com/news/2011-06-26/fukushima-retiree-to-lead-anti-nuclear-motion.html |work=Bloomberg}}</ref> Radiation checks led to bans of some shipments of vegetables and fish.<ref>{{cite news |author=Saito |first=Mari |date=2011-05-07 |title=Japan anti-nuclear protesters rally after PM call to close plant |url=https://www.reuters.com/article/us-japan-nuclear-idUSTRE74610J20110507 |work=Reuters}}</ref>]]
[[File:Decay heat illustration2.PNG|thumb|upright=1.2|Reactor [[decay heat]] as a fraction of full power after the reactor shutdown, using two different correlations. To remove the decay heat, reactors need cooling after the shutdown of the fission reactions. A loss of the ability to remove decay heat caused the [[Fukushima accident]].]]
{{See also|Energy accidents|Nuclear and radiation accidents and incidents|Lists of nuclear disasters and radioactive incidents}}

Some serious [[nuclear and radiation accidents by death toll|nuclear and radiation accidents]] have occurred. The severity of nuclear accidents is generally classified using the [[International Nuclear Event Scale]] (INES) introduced by the [[International Atomic Energy Agency]] (IAEA). The scale ranks anomalous events or accidents on a scale from 0 (a deviation from normal operation that poses no safety risk) to 7 (a major accident with widespread effects). There have been three accidents of level 5 or higher in the civilian nuclear power industry, two of which, the [[Chernobyl accident]] and the [[Fukushima accident]], are ranked at level 7.{{cn|date=August 2025}}

The first major nuclear accidents were the [[Kyshtym disaster]] in the Soviet Union and the [[Windscale fire]] in the United Kingdom, both in 1957. The first major accident at a nuclear reactor in the USA occurred in 1961 at the [[SL-1]], a [[U.S. Army]] experimental nuclear power reactor at the [[Idaho National Laboratory]]. An uncontrolled chain reaction resulted in a [[steam explosion]] which killed the three crew members and caused a [[nuclear meltdown|meltdown]].<ref name=ido19313>''[http://www.id.doe.gov/foia/PDF/IDO-19313.pdf IDO-19313: Additional Analysis of the SL-1 Excursion]'' {{webarchive|url=https://web.archive.org/web/20110927065809/http://www.id.doe.gov/foia/PDF/IDO-19313.pdf |date=2011-09-27 }} ''Final Report of Progress July through October 1962'', November 21, 1962, Flight Propulsion Laboratory Department, General Electric Company, Idaho Falls, Idaho, U.S. Atomic Energy Commission, Division of Technical Information.</ref><ref>{{cite book |last=McKeown |first=William |title=Idaho Falls: The Untold Story of America's First Nuclear Accident |publisher=ECW Press |year=2003 |isbn=978-1-55022-562-4 |location=Toronto, Canada |language=en}}</ref> Another serious accident happened in 1968, when one of the two [[liquid-metal-cooled reactor]]s on board the {{ship|Soviet submarine|K-27}} underwent a [[fuel element failure]], with the emission of gaseous [[fission product]]s into the surrounding air, resulting in 9 crew fatalities and 83 injuries.<ref name=johnston2007>{{cite web |url=http://www.johnstonsarchive.net/nuclear/radevents/radevents1.html |title=Deadliest radiation accidents and other events causing radiation casualties |author=Johnston, Robert |date=2007-09-23 |publisher=Database of Radiological Incidents and Related Events |access-date=2011-03-14 |archive-date=2007-10-23 |archive-url=https://web.archive.org/web/20071023104305/http://www.johnstonsarchive.net/nuclear/radevents/radevents1.html |url-status=live }}</ref>

The Fukushima Daiichi nuclear accident was caused by the [[2011 Tohoku earthquake and tsunami]]. The accident has not caused any radiation-related deaths but resulted in radioactive contamination of surrounding areas. The difficult [[Fukushima disaster cleanup|cleanup operation]] is expected to cost tens of billions of dollars over 40 or more years.<ref name="Richard Schiffman">{{cite news |author=Schiffman |first=Richard |date=2013-03-12 |title=Two years on, America hasn't learned lessons of Fukushima nuclear disaster |url=https://www.theguardian.com/commentisfree/2013/mar/12/fukushima-nuclear-accident-lessons-for-us |url-status=live |archive-url=https://web.archive.org/web/20170202143654/https://www.theguardian.com/commentisfree/2013/mar/12/fukushima-nuclear-accident-lessons-for-us |archive-date=2017-02-02 |access-date=2016-12-12 |work=The Guardian |location=London, England}}</ref><ref name="Martin Fackler">{{cite news |author=Fackler |first=Martin |date=2011-06-01 |title=Report Finds Japan Underestimated Tsunami Danger |url=https://www.nytimes.com/2011/06/02/world/asia/02japan.html?_r=1&ref=world |url-status=live |archive-url=https://web.archive.org/web/20170205043423/http://www.nytimes.com/2011/06/02/world/asia/02japan.html?_r=1&ref=world |archive-date=2017-02-05 |access-date=2017-02-25 |newspaper=The New York Times}}</ref> The [[Three Mile Island accident]] in 1979 was a smaller scale accident, rated at INES level 5. There were no direct or indirect deaths caused by the accident.<ref name="timenuke">{{cite magazine|url=http://www.time.com/time/photogallery/0,29307,1887705,00.html|archive-url=https://web.archive.org/web/20090328130544/http://www.time.com/time/photogallery/0,29307,1887705,00.html|archive-date=March 28, 2009|title=The Worst Nuclear Disasters|date=2009-03-25|access-date=2013-06-22|magazine=[[Time (magazine)|Time]]}}</ref>

The impact of nuclear accidents is controversial. According to [[Benjamin K. Sovacool]], fission [[energy accidents]] ranked first among energy sources in terms of their total economic cost, accounting for 41% of all property damage attributed to energy accidents.<ref>{{Cite journal | last1 = Sovacool | first1 = B.K. | title = The costs of failure: A preliminary assessment of major energy accidents, 1907–2007 | doi = 10.1016/j.enpol.2008.01.040 | journal = Energy Policy | volume = 36 | issue = 5 | pages = 1802–1820 | year = 2008 | bibcode = 2008EnPol..36.1802S }}</ref> Another analysis found that coal, oil, [[liquid petroleum gas]] and hydroelectric accidents (primarily due to the [[Banqiao Dam disaster]]) have resulted in greater economic impacts than nuclear power accidents.<ref>{{cite journal |last1=Burgherr |first1=Peter |last2=Hirschberg |first2=Stefan |title=A Comparative Analysis of Accident Risks in Fossil, Hydro, and Nuclear Energy Chains |journal=Human and Ecological Risk Assessment |date=10 October 2008 |volume=14 |issue=5 |pages=947–973 |doi=10.1080/10807030802387556 |bibcode=2008HERA...14..947B |s2cid=110522982 }}</ref> The study compares latent cancer deaths attributable to nuclear power with immediate deaths from other energy sources per unit of energy generated, and 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 five fatalities) classification. The Chernobyl accident in 1986 caused approximately 50 deaths from direct and indirect effects, and some temporary serious injuries from [[acute radiation syndrome]].<ref name=WHO2012>{{cite web|date=23 April 2011|title=Chernobyl at 25th anniversary – Frequently Asked Questions|publisher=World Health Organisation|access-date=14 April 2012|url=https://www.who.int/ionizing_radiation/chernobyl/20110423_FAQs_Chernobyl.pdf|archive-date=17 April 2012|archive-url=https://web.archive.org/web/20120417011209/http://www.who.int/ionizing_radiation/chernobyl/20110423_FAQs_Chernobyl.pdf|url-status=live}}</ref> The future predicted mortality from increases in cancer rates is estimated at 4000 in the decades to come.<ref>{{cite web |url=http://www.iaea.org/Publications/Magazines/Bulletin/Bull383/boxp6.html |title=Assessing the Chernobyl Consequences |website=International Atomic Energy Agency |archive-url=https://web.archive.org/web/20130830073635/http://www.iaea.org/Publications/Magazines/Bulletin/Bull383/boxp6.html |archive-date=30 August 2013 |df=dmy-all}}</ref><ref name=UNSCEAR_2008_D>{{cite web |url=http://www.unscear.org/docs/reports/2008/11-80076_Report_2008_Annex_D.pdf |title=UNSCEAR 2008 Report to the General Assembly, Annex D |website=United Nations Scientific Committee on the Effects of Atomic Radiation |year=2008 |access-date=2018-12-15 |archive-date=2011-08-04 |archive-url=https://web.archive.org/web/20110804232629/http://www.unscear.org/docs/reports/2008/11-80076_Report_2008_Annex_D.pdf |url-status=live }}</ref><ref>{{cite web |url=http://www.unscear.org/docs/reports/2008/09-86753_Report_2008_GA_Report_corr2.pdf |title=UNSCEAR 2008 Report to the General Assembly |website=United Nations Scientific Committee on the Effects of Atomic Radiation |year=2008 |access-date=2012-05-17 |archive-date=2019-01-05 |archive-url=https://web.archive.org/web/20190105222241/http://www.unscear.org/docs/reports/2008/09-86753_Report_2008_GA_Report_corr2.pdf |url-status=live }}</ref> 

Nuclear power works under an [[insurance]] framework that limits or structures accident liabilities in accordance with national and international conventions.<ref>{{cite web | url=http://www.iaea.org/Publications/Documents/Conventions/liability.html | title=Publications: Vienna Convention on Civil Liability for Nuclear Damage | date=27 August 2014 | publisher=[[International Atomic Energy Agency]] | access-date=8 September 2016 | archive-date=3 March 2016 | archive-url=https://web.archive.org/web/20160303170113/http://www.iaea.org/Publications/Documents/Conventions/liability.html | url-status=live }}</ref> It is often argued that this potential shortfall in liability represents an external cost not included in the cost of nuclear electricity. This cost is small, amounting to about 0.1% of the [[levelized cost of electricity]], according to a study by the [[Congressional Budget Office]] in the United States.<ref>{{cite web|url= http://www.cbo.gov/sites/default/files/05-02-nuclear.pdf|title= Nuclear Power's Role in Generating Electricity|publisher= [[Congressional Budget Office]]|date= May 2008|access-date= 2016-09-08|archive-date= 2014-11-29|archive-url= https://web.archive.org/web/20141129011143/http://www.cbo.gov/sites/default/files/05-02-nuclear.pdf|url-status= live}}</ref> These beyond-regular insurance costs for worst-case scenarios are not unique to nuclear power. [[Hydroelectric power]] plants are similarly not fully insured against a catastrophic event such as [[dam failure]]s. For example, the failure of the [[Banqiao Dam]] caused the death of an estimated 30,000 to 200,000 people, and 11 million people lost their homes. As private insurers base dam insurance premiums on limited scenarios, major disaster insurance in this sector is likewise provided by the state.<ref>{{cite web | url=http://www.damsafety.org/media/Documents/FEMA/AvailabilityOfDamInsurance.pdf | title=Availability of Dam Insurance | date=1999 | access-date=2016-09-08 | archive-date=2016-01-08 | archive-url=https://web.archive.org/web/20160108185336/http://www.damsafety.org/media/documents/fema/availabilityofdaminsurance.pdf }}</ref>

=== Attacks and sabotage ===
{{Main|Vulnerability of nuclear plants to attack|Nuclear terrorism|Nuclear safety in the United States}}
Terrorists could target [[nuclear power plant]]s in an attempt to release [[radioactive contamination]] into the community. The United States 9/11 Commission has said that nuclear power plants were potential targets originally considered for the [[September 11, 2001 attacks]]. An attack on a reactor's [[spent fuel pool]] could also be serious, as these pools are less protected than the reactor core. The release of radioactivity could lead to thousands of near-term deaths and greater numbers of long-term fatalities.<ref name="fas12">{{cite web |last1=Ferguson |first1=Charles D. |last2=Settle |first2=Frank A. |name-list-style=amp |year=2012 |title=The Future of Nuclear Power in the United States |url=https://fas.org/pubs/_docs/Nuclear_Energy_Report-lowres.pdf |url-status=live |archive-url=https://web.archive.org/web/20170525170528/https://fas.org/pubs/_docs/Nuclear_Energy_Report-lowres.pdf |archive-date=2017-05-25 |access-date=2016-07-07 |website=Federation of American Scientists}}</ref>

In the United States, the Nuclear Regulatory Commission carries out "Force on Force" (FOF) exercises at all nuclear power plant sites at least once every three years.<ref name=fas12 /> In the United States, plants are surrounded by a double row of tall fences which are electronically monitored. The plant grounds are patrolled by a sizeable force of armed guards.<ref>{{cite web |title=Nuclear Security – Five Years After 9/11 |url=https://www.nrc.gov/reading-rm/doc-collections/fact-sheets/security-enhancements.html |url-status=live |archive-url=https://web.archive.org/web/20070715045132/http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/security-enhancements.html |archive-date=15 July 2007 |access-date=23 July 2007 |publisher=U.S. Nuclear Regulatory Commission}}</ref>

Insider sabotage is also a threat because insiders can observe and work around security measures. Successful insider crimes depended on the perpetrators' observation and knowledge of security vulnerabilities.<ref>{{cite web |author=Bunn |first1=Matthew |author-link=Matthew Bunn |last2=Sagan |first2=Scott |author2-link=Scott Sagan |name-list-style=amp |date=2014 |title=A Worst Practices Guide to Insider Threats: Lessons from Past Mistakes |url=https://www.amacad.org/content/publications/pubContent.aspx?d=1427 |publisher=The American Academy of Arts & Sciences}}</ref> A fire caused 5–10 million dollars' worth of damage to New York's [[Indian Point Energy Center]] in 1971.<ref>{{Cite news|url=https://www.nytimes.com/1971/11/14/archives/damage-is-put-at-millions-in-blaze-at-con-ed-plant-con-ed-damage.html|title=Damage Is Put at Millions In Blaze at Con Ed Plant|last=McFadden|first=Robert D.|date=1971-11-14|work=The New York Times|access-date=2020-01-15|language=en-US|issn=0362-4331|archive-date=2020-01-15|archive-url=https://web.archive.org/web/20200115181457/https://www.nytimes.com/1971/11/14/archives/damage-is-put-at-millions-in-blaze-at-con-ed-plant-con-ed-damage.html|url-status=live}}</ref> The arsonist was a plant maintenance worker.<ref>{{Cite news|url=https://www.nytimes.com/1972/01/30/archives/mechanic-seized-in-indian-pt-fire-con-ed-employe-accused-of-arson.html|title=Mechanic Seized in Indian Pt. Fire|last=Knight|first=Michael|date=1972-01-30|work=The New York Times|access-date=2020-01-15|language=en-US|issn=0362-4331|archive-date=2020-01-15|archive-url=https://web.archive.org/web/20200115181500/https://www.nytimes.com/1972/01/30/archives/mechanic-seized-in-indian-pt-fire-con-ed-employe-accused-of-arson.html|url-status=live}}</ref>

== Proliferation ==
{{further|Nuclear proliferation}}
{{see also|Plutonium Management and Disposition Agreement}}

Nuclear proliferation is the spread of [[nuclear weapon]]s, fissionable material, and weapons-related nuclear technology to states that do not already possess nuclear weapons. Many technologies and materials associated with the creation of a nuclear power program have a dual-use capability, in that they can also be used to make nuclear weapons. For this reason, nuclear power presents proliferation risks.{{cn|date=August 2025}}

Nuclear power program can become a route leading to a nuclear weapon. An example of this is the concern over [[Iran's nuclear program]].<ref name="dfall2009">{{cite journal |last1=Miller |first1=Steven E. |last2=Sagan |first2=Scott D. |name-list-style=amp |date=Fall 2009 |title=Nuclear power without nuclear proliferation? |journal=Dædalus |volume=138 |issue=4 |page=7 |doi=10.1162/daed.2009.138.4.7 |s2cid=57568427 |doi-access=free}}</ref> The re-purposing of civilian nuclear industries for military purposes would be a breach of the [[Non-Proliferation Treaty]], to which 190 countries adhere. As of April 2012, there are [[Nuclear power by country|thirty one countries]] that have civil nuclear power plants,<ref>{{cite web |url=http://www.world-nuclear.org/info/inf01.html |title=Nuclear Power in the World Today |publisher=World-nuclear.org |access-date=2013-06-22 |archive-date=2013-02-12 |archive-url=https://web.archive.org/web/20130212224344/http://www.world-nuclear.org/info/inf01.html |url-status=live }}</ref> of which nine have nuclear weapons. The vast majority of these [[nuclear weapons state]]s have produced weapons before commercial nuclear power stations.{{cn|date=August 2025}}

A fundamental goal for global security is to minimize the nuclear proliferation risks associated with the expansion of nuclear power.<ref name=dfall2009 /> The [[Global Nuclear Energy Partnership]] was an international effort to create a distribution network in which developing countries in need of energy would receive [[nuclear fuel]] at a discounted rate, in exchange for that nation agreeing to forgo their own indigenous development of a uranium enrichment program. The France-based [[Eurodif]]/''European Gaseous Diffusion Uranium Enrichment Consortium'' is a program that successfully implemented this concept, with [[Nuclear power in Spain|Spain]] and other countries without enrichment facilities buying a share of the fuel produced at the French-controlled enrichment facility, but without a transfer of technology.<ref>{{cite web|url=http://www.world-nuclear.org/info/Nuclear-Fuel-Cycle/Conversion-Enrichment-and-Fabrication/Uranium-Enrichment/|title=Uranium Enrichment|publisher=World Nuclear Association|website=www.world-nuclear.org|access-date=2015-08-12|archive-date=2013-07-01|archive-url=https://web.archive.org/web/20130701071520/http://www.world-nuclear.org/info/Nuclear-Fuel-Cycle/Conversion-Enrichment-and-Fabrication/Uranium-Enrichment/}}</ref> Iran was an early participant from 1974 and remains a shareholder of Eurodif via [[Sofidif]].{{cn|date=August 2025}}

A 2009 United Nations report said that:
<blockquote>the revival of interest in nuclear power could result in the worldwide dissemination of uranium enrichment and spent fuel reprocessing technologies, which present obvious risks of proliferation as these technologies can produce fissile materials that are directly usable in nuclear weapons.<ref name="bks2011">{{cite book |last=Sovacool |first=Benjamin K. |author-link=Benjamin K. Sovacool |title=Contesting the Future of Nuclear Power: A Critical Global Assessment of Atomic Energy |title-link=Contesting the Future of Nuclear Power |date=2011 |publisher=[[World Scientific]] |isbn=978-981-4322-75-1 |location=Hackensack, New Jersey |page=190 |language=en-us}}</ref></blockquote>

On the other hand, power reactors can also reduce nuclear weapon arsenals when military-grade nuclear materials are reprocessed to be used as fuel in nuclear power plants. The [[Megatons to Megawatts Program]] is considered the single most successful [[non-proliferation]] program to date.<ref name="thebulletin.org">{{cite web |url=http://www.thebulletin.org/web-edition/op-eds/support-of-the-megatons-to-megawatts-program |title=The Bulletin of atomic scientists support the megatons to megawatts program |archive-url=https://web.archive.org/web/20110708162741/http://www.thebulletin.org/web-edition/op-eds/support-of-the-megatons-to-megawatts-program |archive-date=2011-07-08 |access-date=2012-09-15 |date=2008-10-23 }}</ref> Up to 2005, the program had processed $8 billion of high enriched, weapons-grade uranium into [[low enriched uranium]] suitable as nuclear fuel for commercial fission reactors by diluting it with [[natural uranium]]. This corresponds to the elimination of 10,000 nuclear weapons.<ref>{{cite web |url=http://www.usec.com/news/megatons-megawatts-eliminates-equivalent-10000-nuclear-warheads |title=Megatons to Megawatts Eliminates Equivalent of 10,000 Nuclear Warheads |publisher=Usec.com |date=2005-09-21 |access-date=2013-06-22 |archive-url=https://web.archive.org/web/20130426130245/http://www.usec.com/news/megatons-megawatts-eliminates-equivalent-10000-nuclear-warheads |archive-date=2013-04-26 }}</ref> For approximately two decades, this material generated nearly 10 percent of all the electricity consumed in the United States, or about half of all U.S. nuclear electricity, with a total of around 7,000{{nbsp}}[[TWh]] of electricity produced.<ref name="ReferenceB">{{cite journal |author=Stover |first=Dawn |date=2014-02-21 |title=More megatons to megawatts |url=http://thebulletin.org/more-megatons-megawatts |journal=The Bulletin |archive-url=https://web.archive.org/web/20170504175156/http://thebulletin.org/more-megatons-megawatts |archive-date=2017-05-04 |access-date=2015-08-11}}</ref> In total it is estimated to have cost $17 billion, a "bargain for US ratepayers", with Russia profiting $12 billion from the deal.<ref name="ReferenceB" /> Much needed profit for the Russian nuclear oversight industry, which after the collapse of the [[Soviet economy]], had difficulties paying for the maintenance and security of the Russian Federation's highly enriched uranium and warheads.<ref name="A Farewell to Arms, 2014">{{cite web|url=http://www.technologyreview.com/article/529861/a-farewell-to-arms/|title=Against Long Odds, MIT's Thomas Neff Hatched a Plan to Turn Russian Warheads into American Electricity|first=Anne-Marie|last=Corley|access-date=2015-08-11|archive-date=2015-09-04|archive-url=https://web.archive.org/web/20150904010100/http://www.technologyreview.com/article/529861/a-farewell-to-arms/|url-status=live}}</ref> The Megatons to Megawatts Program was hailed as a major success by anti-nuclear weapon advocates as it has largely been the driving force behind the sharp reduction in the number of nuclear weapons worldwide since the cold war ended.<ref name="thebulletin.org" /> However, without an increase in nuclear reactors and greater demand for fissile fuel, the cost of dismantling and down blending has dissuaded Russia from continuing their disarmament. As of 2013, Russia appears to not be interested in extending the program.<ref>{{cite news |date=2009-12-05 |title=Future Unclear For 'Megatons To Megawatts' Program |url=https://www.npr.org/templates/story/story.php?storyId=121125743 |url-status=live |archive-url=https://web.archive.org/web/20150112002945/http://www.npr.org/templates/story/story.php?storyId=121125743 |archive-date=2015-01-12 |access-date=2013-06-22 |work=All Things Considered |publisher=National Public Radio |language=en-us |publication-place=United States}}</ref>

== Environmental impact{{anchor|Environmental_issues}} ==
{{Main|Environmental impact of nuclear power}}
[[File:Ikata Nuclear Powerplant.JPG|thumb|upright=1.2|The [[Ikata Nuclear Power Plant]], a [[pressurized water reactor]] that cools by using a secondary coolant [[heat exchanger]] with a large body of water, an alternative cooling approach to large [[cooling towers]]]]
Being a low-carbon energy source with relatively little land-use requirements, nuclear energy can have a positive environmental impact. It also requires a constant supply of significant amounts of water and affects the environment through mining and milling.<ref>{{cite web |title=Life Cycle Assessment of Electricity Generation Options |url=https://unece.org/sites/default/files/2021-10/LCA-2.pdf |access-date=24 November 2021 |archive-date=10 May 2022 |archive-url=https://web.archive.org/web/20220510044223/https://unece.org/sites/default/files/2021-10/LCA-2.pdf |url-status=live }}</ref><ref>{{cite web |title=Nuclear energy and water use in the columbia river basin |url=https://www.umt.edu/bridges/resources/Documents/Blog-Items/C1-Nuclear-Energy-Water.pdf |access-date=24 November 2021 |archive-date=24 November 2021 |archive-url=https://web.archive.org/web/20211124190925/https://www.umt.edu/bridges/resources/Documents/Blog-Items/C1-Nuclear-Energy-Water.pdf |url-status=live }}</ref><ref name="10.1016/j.enpol.2016.03.012"/><ref name="10.3390/ijerph13070700">{{cite journal |last1=Kyne |first1=Dean |last2=Bolin |first2=Bob |title=Emerging Environmental Justice Issues in Nuclear Power and Radioactive Contamination |journal=International Journal of Environmental Research and Public Health |date=July 2016 |volume=13 |issue=7 |page=700 |doi=10.3390/ijerph13070700 |pmid=27420080 |pmc=4962241 |language=en|doi-access=free }}</ref> Its largest potential negative impacts on the environment may arise from its transgenerational risks for nuclear weapons proliferation that may increase risks of their use in the future, risks for problems associated with the management of the radioactive waste such as groundwater contamination, risks for accidents and for risks for various forms of attacks on waste storage sites or reprocessing- and power-plants.<ref name="repr">{{cite web|title=Nuclear Reprocessing: Dangerous, Dirty, and Expensive|url=https://www.ucsusa.org/resources/nuclear-reprocessing-dangerous-dirty-and-expensive|publisher=Union of Concerned Scientists|access-date=26 January 2020|archive-date=15 January 2021|archive-url=https://web.archive.org/web/20210115202035/https://www.ucsusa.org/resources/nuclear-reprocessing-dangerous-dirty-and-expensive|url-status=live}}</ref><ref name="wi1"/><ref name="worldnuclearwastereport"/><ref name="risks"/><ref name="plane1"/><ref name="10.3390/ijerph13070700"/><ref>{{cite journal |last1=Ahearne |first1=John F. |title=Intergenerational Issues Regarding Nuclear Power, Nuclear Waste, and Nuclear Weapons |journal=Risk Analysis |date=2000 |volume=20 |issue=6 |pages=763–770 |doi=10.1111/0272-4332.206070 |pmid=11314726 |bibcode=2000RiskA..20..763A |s2cid=23395683 |language=en |issn=1539-6924}}</ref><ref name="dont">{{cite web |title=CoP 26 Statement {{!}} Don't nuke the Climate! |url=https://dont-nuke-the-climate.org/cop-26-statement |access-date=24 November 2021 |archive-date=25 November 2021 |archive-url=https://web.archive.org/web/20211125033418/https://www.dont-nuke-the-climate.org/cop-26-statement }}</ref> However, these remain mostly only risks as historically there have only been few disasters at nuclear power plants with known relatively substantial environmental impacts.{{cn|date=August 2025}}

=== Carbon emissions ===
{{See also|Life-cycle greenhouse gas emissions of energy sources}}
{{Further|#Historic effect on carbon emissions}}
{{climate change mitigation|Energy}}

[[File:CO2 Emissions from Electricity Production IPCC.png|thumb|upright=1.2|Life-cycle greenhouse gas emissions of electricity supply technologies, median values calculated by [[IPCC]]<ref name="IPCC 2014 Annex III" />]]
Nuclear power is one of the leading [[low carbon power generation]] methods of producing [[electricity]], and in terms of [[Life-cycle greenhouse-gas emissions of energy sources|total life-cycle greenhouse gas emissions per unit of energy generated]], has emission values comparable to or lower than [[renewable energy]].<ref name="Nrel.gov">{{cite web |url=http://www.nrel.gov/analysis/sustain_lca_nuclear.html | title=Nuclear Power Results – Life Cycle Assessment Harmonization| quote=Collectively, life cycle assessment literature shows that nuclear power is similar to other renewable and much lower than fossil fuel in total life cycle GHG emissions. |publisher=nrel.gov |author= [[National Renewable Energy Laboratory]] (NREL) |date=2013-01-24 |access-date=2013-06-22 |archive-url=https://web.archive.org/web/20130702205635/http://www.nrel.gov/analysis/sustain_lca_nuclear.html |archive-date=2013-07-02 }}</ref><ref>{{cite web | url=http://www.nrel.gov/analysis/sustain_lca_results.html | title=Life Cycle Assessment Harmonization Results and Findings. Figure 1 | publisher=NREL | access-date=2016-09-08 | archive-date=2017-05-06 | archive-url=https://web.archive.org/web/20170506114117/http://www.nrel.gov/analysis/sustain_lca_results.html }}</ref> A 2014 analysis of the [[carbon footprint]] literature by the [[Intergovernmental Panel on Climate Change]] (IPCC) reported that the embodied [[Life cycle assessment|total life-cycle]] [[emission intensity]] of nuclear power has a median value of 12{{nbsp}}g {{CO2}}[[carbon dioxide equivalent|eq]]/[[kWh]], which is the lowest among all commercial [[baseload]] energy sources.<ref name="IPCC 2014 Annex III">{{cite web |url=https://www.ipcc.ch/site/assets/uploads/2018/02/ipcc_wg3_ar5_annex-iii.pdf |title=IPCC Working Group III – Mitigation of Climate Change, Annex III: Technology–specific cost and performance parameters |year=2014 |publisher=IPCC |at=table A.III.2 |access-date=2019-01-19 |archive-date=2018-12-14 |archive-url=https://web.archive.org/web/20181214164438/https://www.ipcc.ch/site/assets/uploads/2018/02/ipcc_wg3_ar5_annex-iii.pdf |url-status=live }}</ref><ref name="report.mitigation2014.org">{{cite web |url=https://www.ipcc.ch/site/assets/uploads/2018/02/ipcc_wg3_ar5_annex-ii.pdf |title=IPCC Working Group III – Mitigation of Climate Change, Annex II Metrics & Methodology. |year=2014 |publisher=IPCC |at=section A.II.9.3 |access-date=2019-01-19 |archive-date=2021-04-23 |archive-url=https://web.archive.org/web/20210423212531/https://www.ipcc.ch/site/assets/uploads/2018/02/ipcc_wg3_ar5_annex-ii.pdf |url-status=live }}</ref> This is contrasted with [[coal]] and [[natural gas]] at 820 and 490&nbsp;g {{CO2}} eq/kWh.<ref name="IPCC 2014 Annex III" /><ref name="report.mitigation2014.org" /> As of 2021, nuclear reactors worldwide have helped avoid the emission of 72 billion tonnes of carbon dioxide since 1970, compared to coal-fired electricity generation, according to a report.<ref name="Kharecha Pushker A 2013 4889–4895" /><ref>{{cite web |url=https://world-nuclear.org/getmedia/264c91d4-d443-4edb-bc08-f5175c0ac6ba/performance-report-2021-cop26.pdf.aspx |title=World nuclear performance report 2021 |publisher=World Nuclear Association |access-date=2022-04-19 |archive-date=2022-04-03 |archive-url=https://web.archive.org/web/20220403142850/https://world-nuclear.org/getmedia/264c91d4-d443-4edb-bc08-f5175c0ac6ba/performance-report-2021-cop26.pdf.aspx |url-status=deviated }}</ref>

=== Radiation ===
The average dose from natural [[background radiation]] is 2.4 [[millisievert]] per year (mSv/a) globally. It varies between 1{{nbsp}}mSv/a and 13{{nbsp}}mSv/a, depending mostly on the geology of the location. According to the United Nations ([[UNSCEAR]]), regular nuclear power plant operations, including the nuclear fuel cycle, increases this amount by 0.0002{{nbsp}}mSv/a of public exposure as a global average. The average dose from operating nuclear power plants to the local populations around them is less than 0.0001{{nbsp}}mSv/a.<ref name=UNSCEAR_GA>{{cite web |url=http://www.unscear.org/docs/reports/2008/09-86753_Report_2008_GA_Report_corr2.pdf |title=UNSCEAR 2008 Report to the General Assembly |publisher=United Nations Scientific Committee on the Effects of Atomic Radiation |year=2008 |access-date=2012-05-17 |archive-date=2019-01-05 |archive-url=https://web.archive.org/web/20190105222241/http://www.unscear.org/docs/reports/2008/09-86753_Report_2008_GA_Report_corr2.pdf |url-status=live }}</ref> For comparison, the average dose to those living within {{convert|50|miles}} of a [[coal power plant]] is over three times this dose, at 0.0003{{nbsp}}mSv/a.<ref>{{cite web |url=http://www.nsc.org/resources/issues/rad/exposure.aspx |title=National Safety Council |publisher=Nsc.org |access-date=18 June 2013 |url-status=live |archive-url= https://web.archive.org/web/20091012025401/http://www.nsc.org/resources/issues/rad/exposure.aspx |archive-date=12 October 2009 }}</ref>

Chernobyl resulted in the most affected surrounding populations and male recovery personnel receiving an average initial 50 to 100{{nbsp}}mSv over a few hours to weeks, while the remaining global legacy of the worst nuclear power plant accident in average exposure is 0.002{{nbsp}}mSv/a and is continuously dropping at the decaying rate, from the initial high of 0.04{{nbsp}}mSv per person averaged over the entire populace of the Northern Hemisphere in the year of the accident in 1986.<ref name=UNSCEAR_GA />

== Debate ==
{{Main|Nuclear power debate}}
{{See also|Nuclear energy policy|Pro-nuclear movement|Anti-nuclear movement}}
The nuclear power debate concerns the controversy which has surrounded the deployment and use of nuclear fission reactors to generate electricity from nuclear fuel for civilian purposes.<ref name=eleven /><ref name="jstor.org">{{cite journal |author=MacKenzie |first=James J. |date=December 1977 |title=Review of The Nuclear Power Controversy by Arthur W. Murphy |journal=The Quarterly Review of Biology |volume=52 |pages=467–468 |doi=10.1086/410301 |jstor=2823429 |number=4}}</ref><ref name="marcuse.org" />

Proponents of nuclear energy regard it as a [[sustainable energy]] source that reduces [[carbon emissions]] and increases [[energy security]] by decreasing dependence on other energy sources that are often dependent on imports.<ref name="bloomberg.com">{{cite news |url=https://www.bloomberg.com/apps/news?pid=10000103&sid=aXb5iuqdZoD4&refer=us |title=U.S. Energy Legislation May Be 'Renaissance' for Nuclear Power |work=Bloomberg |access-date=2017-03-10 |archive-date=2009-06-26 |archive-url=https://web.archive.org/web/20090626182130/http://www.bloomberg.com/apps/news?pid=10000103 }}.</ref><ref>{{cite news |last=Patterson |first=Thom |date=2013-11-03 |title=Climate change warriors: It's time to go nuclear |url=http://www.cnn.com/2013/11/03/world/nuclear-energy-climate-change-scientists/index.html |newspaper=CNN |access-date=2013-11-05 |archive-date=2013-11-04 |archive-url=https://web.archive.org/web/20131104031820/http://www.cnn.com/2013/11/03/world/nuclear-energy-climate-change-scientists/index.html |url-status=live }}</ref><ref>{{cite web| url= http://www.world-nuclear.org/info/inf10.html| title= Renewable Energy and Electricity| date= June 2010| publisher= World Nuclear Association| access-date= 2010-07-04| archive-date= 2010-06-19| archive-url= https://web.archive.org/web/20100619061729/http://world-nuclear.org/info/inf10.html}}</ref> For example, proponents note that annually, nuclear-generated electricity reduces 470 million metric tons of carbon dioxide emissions that would otherwise come from fossil fuels.<ref>{{cite web |title=Climate |url=https://www.nei.org/advantages/climate |access-date=18 February 2022 |archive-date=18 February 2022 |archive-url=https://web.archive.org/web/20220218141259/https://www.nei.org/advantages/climate |url-status=live }}</ref> Additionally, the amount of comparatively low waste that nuclear energy does create is safely disposed of by the large scale nuclear energy production facilities or it is repurposed/recycled for other energy uses.<ref>{{cite web |title=Radioactive Waste Management |url=https://www.world-nuclear.org/information-library/nuclear-fuel-cycle/nuclear-wastes/radioactive-waste-management.aspx |date=February 2022 |access-date=2022-02-18 |archive-date=2016-02-01 |archive-url=https://web.archive.org/web/20160201064831/http://www.world-nuclear.org/info/Nuclear-Fuel-Cycle/Nuclear-Wastes/Radioactive-Waste-Management/ |url-status=live }}</ref> 

Proponents also claim that the present quantity of nuclear waste is small and can be reduced through the latest technology of newer reactors and that the operational safety record of fission-electricity in terms of deaths is so far "unparalleled".<ref name="Bernard L. Cohen 1990"/> Kharecha and [[James Hansen|Hansen]] estimated that "global nuclear power has prevented an average of 1.84 million air pollution-related deaths and 64 gigatonnes of CO<sub>2</sub>-equivalent (Gt{{CO2}}-eq) greenhouse gas (GHG) emissions that would have resulted from fossil fuel burning" and, if continued, it could prevent up to 7 million deaths and 240{{nbsp}}Gt{{CO2}}-eq emissions by 2050.<ref name="Kharecha Pushker A 2013 4889–4895" />

Proponents also bring to attention the opportunity cost of using other forms of electricity. For example, the [[United States Environmental Protection Agency]] estimates that coal kills 30,000 people a year as a result of its environmental impact,<ref>{{cite journal |title=Particulate matter air pollution and national and county life expectancy loss in the USA: A spatiotemporal analysis |date=23 July 2019| doi=10.1371/journal.pmed.1002856 | last1=Bennett | first1=James E. | last2=Tamura-Wicks | first2=Helen | last3=Parks | first3=Robbie M. | last4=Burnett | first4=Richard T. | last5=Pope | first5=C. Arden | last6=Bechle | first6=Matthew J. | last7=Marshall | first7=Julian D. | last8=Danaei | first8=Goodarz | last9=Ezzati | first9=Majid | journal=PLOS Medicine | volume=16 | issue=7 | article-number=e1002856 | pmid=31335874 | pmc=6650052 |doi-access=free }}</ref> while 60 people died in the Chernobyl disaster.<ref>{{cite web |title=Nuclear Power and Energy Independence |url=https://reason.com/2008/10/22/nuclear-power-and-energy-indep/ |date=22 October 2008 |access-date=18 February 2022 |archive-date=18 February 2022 |archive-url=https://web.archive.org/web/20220218141253/https://reason.com/2008/10/22/nuclear-power-and-energy-indep/ |url-status=live }}</ref> 
A real world example of impact provided by proponents is the 650,000 ton increase in carbon emissions in the two months following the closure of the [[Vermont Yankee]] nuclear plant.<ref>{{cite web |title=Climate |url=https://www.nuclearmatters.com/climate |access-date=18 February 2022 |archive-date=18 February 2022 |archive-url=https://web.archive.org/web/20220218141249/https://www.nuclearmatters.com/climate |url-status=live }}</ref>

Opponents believe that nuclear power poses many threats to people's health and environment<ref>{{cite book |author=Weart |first=Spencer R. |author-link=Spencer R. Weart |title=The Rise of Nuclear Fear |date=2012 |publisher=Harvard University Press |language=en-us}}</ref><ref name="Sturgis">{{cite web |url=http://www.southernstudies.org/2009/04/post-4.html |title=Investigation: Revelations about Three Mile Island disaster raise doubts over nuclear plant safety |last=Sturgis |first=Sue |publisher=[[Institute for Southern Studies]] |access-date=2010-08-24 |archive-url=https://web.archive.org/web/20100418063024/http://www.southernstudies.org/2009/04/post-4.html |archive-date=2010-04-18 }}</ref> such as the risk of nuclear weapons proliferation, long-term safe waste management and terrorism in the future.<ref name=gierec>{{cite web |publisher= Greenpeace International and European Renewable Energy Council |date= January 2007 |url= http://www.energyblueprint.info/fileadmin/media/documents/energy_revolution.pdf |title= Energy Revolution: A Sustainable World Energy Outlook |page= 7 |access-date= 2010-02-28 |archive-date= 2009-08-06 |archive-url= https://web.archive.org/web/20090806121526/http://www.energyblueprint.info/fileadmin/media/documents/energy_revolution.pdf }}</ref><ref name=protest>{{cite book |last1=Giugni |first1=Marco |title=Social protest and policy change: ecology, antinuclear, and peace movements in comparative perspective |date=2004 |publisher=Rowman & Littlefield |location=Lanham |isbn=978-0-7425-1826-1 |url=https://books.google.com/books?id=Kn6YhNtyVigC&pg=PA44 |page=44 |access-date=2015-10-18 |archive-date=2023-12-24 |archive-url=https://web.archive.org/web/20231224045246/https://books.google.com/books?id=Kn6YhNtyVigC&pg=PA44#v=onepage&q&f=false |url-status=live }}</ref> They also contend that nuclear power plants are complex systems where many things can and have gone wrong.<ref name="bksenpol">{{cite journal |author=Sovacool |first=Benjamin K. |author-link=Benjamin K. Sovacool |year=2008 |title=The costs of failure: A preliminary assessment of major energy accidents, 1907–2007 |journal=[[Energy Policy (journal)|Energy Policy]] |volume=36 |issue=5 |pages=1802–1820 |bibcode=2008EnPol..36.1802S |doi=10.1016/j.enpol.2008.01.040}}</ref><ref>{{cite book |last1=Cooke |first1=Stephanie |title=[[In Mortal Hands: A Cautionary History of the Nuclear Age]] |date=2009 |publisher=Bloomsbury |location=New York |isbn=978-1-59691-617-3 |page=280 }}</ref> 

Critics find that one of the largest drawbacks to building new nuclear fission power plants are the high costs when compared to alternatives of sustainable energy sources.<ref name="cnnchina">{{cite news |last1=Griffiths |first1=James |title=China's gambling on a nuclear future, but is it destined to lose? |url=https://edition.cnn.com/2019/09/13/business/china-nuclear-climate-intl-hnk/index.html |access-date=25 November 2021 |work=CNN |archive-date=25 November 2021 |archive-url=https://web.archive.org/web/20211125101428/https://edition.cnn.com/2019/09/13/business/china-nuclear-climate-intl-hnk/index.html |url-status=live }}</ref><ref name="10.1016/j.erss.2014.04.015">{{cite journal |last1=Ramana |first1=M. V. |last2=Mian |first2=Zia |title=One size doesn't fit all: Social priorities and technical conflicts for small modular reactors |journal=Energy Research & Social Science |date=1 June 2014 |volume=2 |pages=115–124 |doi=10.1016/j.erss.2014.04.015 |bibcode=2014ERSS....2..115R |language=en |issn=2214-6296}}</ref><ref name="10.1016/j.enpol.2016.03.012">{{cite journal |last1=Ramana |first1=M. V. |last2=Ahmad |first2=Ali |title=Wishful thinking and real problems: Small modular reactors, planning constraints, and nuclear power in Jordan |journal=Energy Policy |date=1 June 2016 |volume=93 |pages=236–245 |doi=10.1016/j.enpol.2016.03.012 |bibcode=2016EnPol..93..236R |language=en |issn=0301-4215}}</ref><ref name="10.1177/2399654418777765">{{cite journal |last1=Meckling |first1=Jonas |title=Governing renewables: Policy feedback in a global energy transition |journal=Environment and Planning C: Politics and Space |date=1 March 2019 |volume=37 |issue=2 |pages=317–338 |doi=10.1177/2399654418777765 |bibcode=2019EnPlC..37..317M |s2cid=169975439 |language=en |issn=2399-6544}}</ref> 
Proponents note that focusing on the [[levelized cost of energy]] (LCOE), however, ignores the value premium associated with 24/7 dispatchable electricity and the cost of storage and backup systems necessary to integrate variable energy sources into a reliable electrical grid.<ref>{{Cite web|url=https://www.reutersevents.com/nuclear/new-nuclear-lto-among-cheapest-low-carbon-options-report-shows|title=New nuclear, LTO among cheapest low carbon options, report shows|website=Reuters Events|access-date=2022-04-19|archive-date=2022-05-19|archive-url=https://web.archive.org/web/20220519113259/https://www.reutersevents.com/nuclear/new-nuclear-lto-among-cheapest-low-carbon-options-report-shows|url-status=live}}</ref> "Nuclear thus remains the dispatchable low-carbon technology with the lowest expected costs in 2025. Only large hydro reservoirs can provide a similar contribution at comparable costs but remain highly dependent on the natural endowments of individual countries."<ref>{{Cite web|url=https://www.iea.org/reports/projected-costs-of-generating-electricity-2020|title=Projected Costs of Generating Electricity 2020 – Analysis|website=IEA|date=9 December 2020 |access-date=2020-12-12|archive-date=2022-04-02|archive-url=https://web.archive.org/web/20220402003026/https://www.iea.org/reports/projected-costs-of-generating-electricity-2020|url-status=live}}</ref>
[[File:Grüne protests against nuclear energy.jpg|thumb|Anti-nuclear protest near [[Deep geological repository|nuclear waste disposal centre]] at [[Gorleben]] in northern Germany]]
Overall, many opponents find that nuclear energy cannot meaningfully contribute to climate change mitigation. In general, they find it to be too dangerous, too expensive, to take too long for deployment, as much as to be an obstacle to achieving a transition towards sustainability and carbon-neutrality.<ref name="10.5281/zenodo.5573718">{{cite periodical |title=Kernenergie und Klima |periodical=Diskussionsbeiträge der Scientists for Future |date=16 October 2021 |doi=10.5281/zenodo.5573718 |doi-access=free |language=de |last1=Wealer |first1=Ben |last2=Breyer |first2=Christian |last3=Hennicke |first3=Peter |last4=Hirsch |first4=Helmut |last5=von Hirschhausen |first5=Christian |last6=Klafka |first6=Peter |last7=Kromp-Kolb |first7=Helga |last8=Präger |first8=Fabian |last9=Steigerwald |first9=Björn |last10=Traber |first10=Thure |last11=Baumann |first11=Franz |last12=Herold |first12=Anke |last13=Kemfert |first13=Claudia |last14=Kromp |first14=Wolfgang |last15=Liebert |first15=Wolfgang |last16=Müschen |first16=Klaus }}</ref><ref>{{cite web |title=Empirically grounded technology forecasts and the energy transition |website=University of Oxford |url=https://www.inet.ox.ac.uk/files/energy_transition_paper-INET-working-paper.pdf |archive-url=https://web.archive.org/web/20211018072825/https://www.inet.ox.ac.uk/files/energy_transition_paper-INET-working-paper.pdf |archive-date=2021-10-18 |language=en}}</ref><ref name="slowexpensive">{{cite news |title=Nuclear energy too slow, too expensive to save climate: report |url=https://www.reuters.com/article/us-energy-nuclearpower-idUSKBN1W909J |access-date=24 November 2021 |work=Reuters |date=24 September 2019 |language=en |archive-date=16 March 2021 |archive-url=https://web.archive.org/web/20210316222844/https://www.reuters.com/article/us-energy-nuclearpower-idUSKBN1W909J |url-status=live }}</ref><ref>{{cite web |last1=Farmer |first1=J. Doyne |last2=Way |first2=Rupert |last3=Mealy |first3=Penny |title=Estimating the costs of energy transition scenarios using probabilistic forecasting methods |website=University of Oxford |date=December 2020 |url=https://www.inet.ox.ac.uk/files/energy_transition_paper-INET-working-paper.pdf |archive-url=https://web.archive.org/web/20211018072825/https://www.inet.ox.ac.uk/files/energy_transition_paper-INET-working-paper.pdf |archive-date=2021-10-18 |language=en}}</ref> These opponents find nuclear to be effectively a distraction in the competition for resources (i.e. human, financial, time, infrastructure and expertise) for the deployment and development of alternative, sustainable, [[energy system]] technologies<ref name="gates2">{{cite news |title=Scientists pour cold water on Bill Gates' nuclear plans {{!}} DW {{!}} 08.11.2021 |url=https://www.dw.com/en/scientists-pour-cold-water-on-bill-gates-nuclear-plans/a-59751405 |access-date=24 November 2021 |work=Deutsche Welle (www.dw.com) |archive-date=24 November 2021 |archive-url=https://web.archive.org/web/20211124073731/https://www.dw.com/en/scientists-pour-cold-water-on-bill-gates-nuclear-plans/a-59751405 |url-status=live }}</ref><ref name="cd1">{{cite web |title=Scientists Warn Experimental Nuclear Plant Backed by Bill Gates Is 'Outright Dangerous' |url=https://www.commondreams.org/news/2021/11/17/scientists-warn-experimental-nuclear-plant-backed-bill-gates-outright-dangerous |website=Common Dreams |access-date=24 November 2021 |language=en |archive-date=24 November 2021 |archive-url=https://web.archive.org/web/20211124190922/https://www.commondreams.org/news/2021/11/17/scientists-warn-experimental-nuclear-plant-backed-bill-gates-outright-dangerous |url-status=live }}</ref><ref name="mil1">{{cite web |title=Hidden military implications of 'building back' with new nuclear in the UK |url=https://www.sgr.org.uk/sites/default/files/2021-09/SGR_RS03_2021_Johnstone%2BStirling.pdf |access-date=24 November 2021 |archive-date=23 October 2021 |archive-url=https://web.archive.org/web/20211023044245/https://www.sgr.org.uk/sites/default/files/2021-09/SGR_RS03_2021_Johnstone%2BStirling.pdf |url-status=live }}</ref><ref name="10.5281/zenodo.5573718"/><ref>{{cite journal |last1=Szyszczak |first1=Erika |title=State aid for energy infrastructure and nuclear power projects |journal=ERA Forum |date=1 July 2015 |volume=16 |issue=1 |pages=25–38 |doi=10.1007/s12027-015-0371-6 |s2cid=154617833 |language=en |issn=1863-9038}}</ref>

Nevertheless, there is ongoing research and debate over costs of new nuclear, especially in regions where seasonal energy storage is difficult to provide and which aim to [[fossil fuel phase-out|phase out fossil fuels]] in favor of [[low carbon power]] faster than the global average.<ref>{{cite news |title=Does Hitachi decision mean the end of UK's nuclear ambitions? |url=https://www.theguardian.com/business/2019/jan/17/does-the-hitachi-decision-mean-the-end-of-the-uks-nuclear-dream |work=The Guardian |date=17 January 2019}}</ref> Some find that financial transition costs for a 100% renewables-based European energy system that has completely phased out nuclear energy could be more costly by 2050 based on current technologies (i.e. not considering potential advances in e.g. [[green hydrogen]], transmission and flexibility capacities, ways to reduce energy needs, geothermal energy and fusion energy) when the grid only extends across Europe.<ref>{{cite journal |last1=Zappa |first1=William |last2=Junginger |first2=Martin |last3=van den Broek |first3=Machteld |title=Is a 100% renewable European power system feasible by 2050? |journal=Applied Energy |date=1 January 2019 |volume=233-234 |pages=1027–1050 |doi=10.1016/j.apenergy.2018.08.109 |s2cid=116855350 |language=en |issn=0306-2619|doi-access=free |bibcode=2019ApEn..233.1027Z }}</ref> Arguments of economics and safety are used by both sides of the debate.

=== Comparison with renewable energy ===
{{See also|Renewable energy debate}}

Slowing [[global warming]] requires a transition to a [[low-carbon economy]], mainly by burning far less [[fossil fuel]]. This has generated considerable interest and dispute in determining the best path forward to rapidly replace fossil-based fuels in the global [[energy mix]],<ref>{{cite magazine|url=https://spectrum.ieee.org/what-it-would-really-take-to-reverse-climate-change|title=What It Would Really Take to Reverse Climate Change|magazine=IEEE Spectrum|author1=Ross Koningstein|author2=David Fork|date=18 November 2014|access-date=13 January 2019|archive-date=24 November 2016|archive-url=https://web.archive.org/web/20161124081052/https://spectrum.ieee.org/energy/renewables/what-it-would-really-take-to-reverse-climate-change|url-status=live}}</ref><ref>{{cite web |author=Johnson |first=Nathanael |date=2018 |title=Agree to Agree Fights over renewable standards and nuclear power can be vicious. Here's a list of things that climate hawks agree on. |url=https://grist.org/article/most-paths-to-a-clean-energy-future-start-the-same-way/ |url-status=live |archive-url=https://web.archive.org/web/20190116100151/https://grist.org/article/most-paths-to-a-clean-energy-future-start-the-same-way/ |archive-date=2019-01-16 |access-date=2019-01-16 |work=[[Grist (magazine)|Grist]]}}</ref> with intense academic debate.<ref>{{cite news |url=https://www.utilitydive.com/news/whats-missing-from-the-100-renewable-energy-debate/447658/ |title=What's missing from the 100% renewable energy debate |work=Utility Dive |access-date=2019-01-05 |archive-date=2019-01-06 |archive-url=https://web.archive.org/web/20190106010934/https://www.utilitydive.com/news/whats-missing-from-the-100-renewable-energy-debate/447658/ |url-status=live }}</ref><ref name="GTM-NewFront">{{cite web |last1=Deign |first1=Jason |title=Renewables or Nuclear? A New Front in the Academic War Over Decarbonization |url=https://www.greentechmedia.com/articles/read/the-war-over-renewables-versus-nuclear |website=gtm |publisher=Greentech Media |date=March 30, 2018 |access-date=December 13, 2018 |archive-date=December 15, 2018 |archive-url=https://web.archive.org/web/20181215224058/https://www.greentechmedia.com/articles/read/the-war-over-renewables-versus-nuclear |url-status=live }}</ref> Sometimes the IEA says that countries without nuclear should develop it as well as their renewable power.<ref>{{Cite web|url=https://www.dailysabah.com/energy/2019/07/06/turkey-may-benefit-from-nuclear-power-in-its-bid-for-clean-energy|title=Turkey may benefit from nuclear power in its bid for clean energy|website=DailySabah|date=6 July 2019|access-date=2019-07-14|archive-date=2019-07-14|archive-url=https://web.archive.org/web/20190714182533/https://www.dailysabah.com/energy/2019/07/06/turkey-may-benefit-from-nuclear-power-in-its-bid-for-clean-energy|url-status=live}}</ref>
{{Pie chart
| thumb = right
| caption = World total primary energy supply of 162,494 [[TWh]] (or 13,792 [[tonne of oil equivalent|Mtoe]]) by fuels in 2017 (IEA, 2019)<ref name="IEA-Report-keyworld-2019">{{cite web |title = 2019 Key World Energy Statistics |date = 2019 |publisher = IEA |url = https://webstore.iea.org/download/direct/2831?fileName=Key_World_Energy_Statistics_2019.pdf }}{{Dead link|date=August 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>{{rp|6,8}}
| other =
| label1 = Oil
| value1 = 32
| color1 = #7C6250
| label2 = Coal/Peat/Shale
| value2 = 27.1
| color2 = #313c42
| label3 = Natural Gas
| value3 = 22.2
| color3 = #ef8e39
| label4 = Biofuels and waste
| value4 = 9.5
| color4 = #ABFF57
| label5 = Nuclear
| value5 = 4.9
| color5 = #de2821
| label6 = Hydro
| value6 = 2.5
| color6 = #005CE6
| label7 = Others ([[Renewables]])
| value7 = 1.8
| color7 = #00CC4B
}}

Nuclear power is comparable to, and in some cases lower, than many renewable energy sources in terms of lives lost per unit of electricity delivered.<ref name="MarkandyaWilkinson2007" /><ref name="without the hot air" /><ref name="Starfelt">{{cite web |last1=Starfelt |first1=Nils |last2=Wikdahl |first2=Carl-Erik |title=Economic Analysis of Various Options of Electricity Generation – Taking into Account Health and Environmental Effects |url=http://manhaz.cyf.gov.pl/manhaz/strona_konferencja_EAE-2001/15%20-%20Polenp~1.pdf |archive-url=https://web.archive.org/web/20070927230434/http://manhaz.cyf.gov.pl/manhaz/strona_konferencja_EAE-2001/15%20-%20Polenp~1.pdf |archive-date=2007-09-27 |access-date=2012-09-08}}</ref> 

Nuclear reactors produce a much smaller volume of waste compared to renewable energy sources, although nuclear waste is much more toxic, expensive to manage and longer-lived compared to waste from renewable technologies.<ref>{{cite journal |author=Biello |first=David |date=2009-01-28 |title=Spent Nuclear Fuel: A Trash Heap Deadly for 250,000 Years or a Renewable Energy Source? |url=http://www.scientificamerican.com/article.cfm?id=nuclear-waste-lethal-trash-or-renewable-energy-source |url-status=live |journal=Scientific American |archive-url=https://web.archive.org/web/20170903121314/https://www.scientificamerican.com/article.cfm?id=nuclear-waste-lethal-trash-or-renewable-energy-source |archive-date=2017-09-03 |access-date=2014-01-24}}</ref><ref name="worldnuclearwastereport"/> 
Nuclear waste can be dangerous if leaked to the environment, and need to be stored safely for thousands or even hundreds of thousand of years.<ref>{{cite web |last1=Stothard |first1=Michael |title=Nuclear waste: keep out for 100,000 years |url=https://www.ft.com/content/db87c16c-4947-11e6-b387-64ab0a67014c |archive-url=https://ghostarchive.org/archive/20221210/https://www.ft.com/content/db87c16c-4947-11e6-b387-64ab0a67014c |archive-date=2022-12-10 |url-access=subscription |url-status=live |website=Financial Times |access-date=28 November 2021 |date=14 July 2016}}</ref><ref>{{cite web |title=High-Level Waste |url=https://www.nrc.gov/waste/high-level-waste.html |website=NRC Web |access-date=28 November 2021 |archive-date=27 November 2021 |archive-url=https://web.archive.org/web/20211127082101/https://www.nrc.gov/waste/high-level-waste.html |url-status=live }}</ref><ref>{{cite journal |last1=Grambow |first1=Bernd |title=Mobile fission and activation products in nuclear waste disposal |journal=Journal of Contaminant Hydrology |date=12 December 2008 |volume=102 |issue=3 |pages=180–186 |doi=10.1016/j.jconhyd.2008.10.006 |pmid=19008015 |bibcode=2008JCHyd.102..180G |language=en |issn=0169-7722}}</ref>

Nuclear plants are also far more complex to decommission compared to renewable energy plants. A nuclear plant needs to be disassembled and removed and much of the disassembled nuclear plant needs to be stored as low-level nuclear waste for a few decades.<ref>{{cite web|url=http://www.unep.org/yearbook/2012/pdfs/UYB_2012_CH_3.pdf|title=Closing and Decommissioning Nuclear Power Plants|date=2012-03-07|website=United Nations Environment Programme|archive-url=http://arquivo.pt/wayback/20160518164428/http://www.unep.org/yearbook/2012/pdfs/UYB_2012_CH_3.pdf|archive-date=2016-05-18|access-date=2013-01-04}}</ref> 

Nuclear power may also pose the risk of [[nuclear proliferation]]. Separated [[plutonium]] and [[enriched uranium]] could be used for [[nuclear weapon]]s, which pose a substantial global risk to human civilization and the environment.<ref name="wi1">{{cite web|title=Is nuclear power the answer to climate change?|url=https://wiseinternational.org/nuclear-energy/nuclear-power-answer-climate-change|publisher=World Information Service on Energy|access-date=1 February 2020|archive-date=22 April 2020|archive-url=https://web.archive.org/web/20200422202713/https://wiseinternational.org/nuclear-energy/nuclear-power-answer-climate-change|url-status=live}}</ref><ref name="worldnuclearwastereport">{{cite web |title=World Nuclear Waste Report |url=https://worldnuclearwastereport.org/ |access-date=25 October 2021 |archive-date=15 June 2023 |archive-url=https://web.archive.org/web/20230615183744/https://worldnuclearwastereport.org/ |url-status=live }}</ref><ref name="risks">{{cite web |last1=Smith |first1=Brice |title=Insurmountable Risks: The Dangers of Using Nuclear Power to Combat Global Climate Change – Institute for Energy and Environmental Research |url=https://ieer.org/resource/books/insurmountable-risks-dangers-nuclear/ |url-status=live |archive-url=https://web.archive.org/web/20230530034945/https://ieer.org/resource/books/insurmountable-risks-dangers-nuclear/ |archive-date=30 May 2023 |access-date=24 November 2021 |language=en}}</ref><ref name="plane1">{{cite journal |last1=Prăvălie |first1=Remus |last2=Bandoc |first2=Georgeta |title=Nuclear energy: Between global electricity demand, worldwide decarbonisation imperativeness, and planetary environmental implications |journal=Journal of Environmental Management |date=1 March 2018 |volume=209 |pages=81–92 |doi=10.1016/j.jenvman.2017.12.043 |pmid=29287177 |bibcode=2018JEnvM.209...81P |issn=1095-8630}}</ref>

====Speed of transition and investment needed====
Analysis in 2015 by professor [[Barry Brook (scientist)|Barry W. Brook]] and colleagues found that nuclear energy could displace or remove fossil fuels from the electric grid completely within 10 years. This finding was based on the historically modest and proven rate at which nuclear energy was added in France and Sweden during their building programs in the 1980s.<ref name="journals.plos.org">{{cite journal|title=Potential for Worldwide Displacement of Fossil-Fuel Electricity by Nuclear Energy in Three Decades Based on Extrapolation of Regional Deployment Data|first1=Staffan A.|last1=Qvist|first2=Barry W.|last2=Brook|date=13 May 2015|journal=PLOS ONE|volume=10|issue=5|article-number=e0124074|doi=10.1371/journal.pone.0124074|pmid=25970621|pmc=4429979|bibcode=2015PLoSO..1024074Q|doi-access=free}}</ref><ref>{{cite web |url=https://www.discovery.com/dscovrd/tech/report-world-can-rid-itself-of-fossil-fuel-dependence-in-as-little-as-10-years/ |title=Report: World can Rid Itself of Fossil Fuel Dependence in as little as 10 years |work=Discovery |access-date=2019-01-31 |archive-date=2019-02-01 |archive-url=https://web.archive.org/web/20190201120207/http://www.discovery.com/dscovrd/tech/report-world-can-rid-itself-of-fossil-fuel-dependence-in-as-little-as-10-years/ |url-status=live }}</ref> In a similar analysis, Brook had earlier determined that 50% of all [[world energy consumption|global energy]], including transportation [[synthetic fuels]] etc., could be generated within approximately 30 years if the global nuclear fission build rate was identical to historical proven installation rates calculated in [[Gigawatt|GW]] per year per unit of global [[GDP]] (GW/year/$).<ref name="brook_could_2012">{{cite journal |author=Brook |first=Barry W. |year=2012 |title=Could nuclear fission energy, etc., solve the greenhouse problem? The affirmative case |journal=Energy Policy |volume=42 |pages=4–8 |bibcode=2012EnPol..42....4B |doi=10.1016/j.enpol.2011.11.041}}</ref> This is in contrast to the conceptual studies for [[100% renewable energy]] systems, which would require an order of magnitude more costly global investment per year, which has no historical precedent.<ref name="loftus_critical_2015">{{cite journal |last1=Loftus |first1=Peter J. |last2=Cohen |first2=Armond M. |last3=Long |first3=Jane C. S. |last4=Jenkins |first4=Jesse D. |date=January 2015 |title=A critical review of global decarbonization scenarios: what do they tell us about feasibility? |url=https://www.qualenergia.it/sites/default/files/articolo-doc/wcc324-1.pdf |journal=WIREs Climate Change |volume=6 |issue=1 |pages=93–112 |bibcode=2015WIRCC...6...93L |doi=10.1002/wcc.324 |s2cid=4835733 |archive-url=https://web.archive.org/web/20190806203759/https://www.qualenergia.it/sites/default/files/articolo-doc/wcc324-1.pdf |archive-date=2019-08-06 |access-date=2019-12-01}}</ref> These renewable scenarios would also need far greater land devoted to onshore wind and onshore solar projects.<ref name="brook_could_2012" /><ref name="loftus_critical_2015" /> Brook notes that the "principal limitations on nuclear fission are not technical, economic or fuel-related, but are instead linked to complex issues of societal acceptance, fiscal and political inertia, and inadequate critical evaluation of the real-world constraints facing [the other] low-carbon alternatives."<ref name="brook_could_2012" />

====Land use====
The median land area used by US nuclear power stations per 1{{nbsp}}GW installed capacity is {{convert|1.3|sqmi|km2|lk=on}}.<ref name=NEI_news_2015>{{cite web |title=Land Needs for Wind, Solar Dwarf Nuclear Plant's Footprint |url=https://www.nei.org/news/2015/land-needs-for-wind-solar-dwarf-nuclear-plants |website=nei.org |publisher=NEI |date=July 9, 2015 |access-date=January 6, 2019 |archive-date=January 7, 2019 |archive-url=https://web.archive.org/web/20190107072153/https://www.nei.org/news/2015/land-needs-for-wind-solar-dwarf-nuclear-plants |url-status=live }}</ref><ref name=Energy_gov_Fast_Facts >{{cite web | url=https://www.energy.gov/sites/prod/files/2019/01/f58/Ultimate%20Fast%20Facts%20Guide-PRINT.pdf | title=THE ULTIMATE FAST FACTS GUIDE TO NUCLEAR ENERGY | last= | first= | work=[[United States Department of Energy]] | date=2019-01-01 | access-date=2022-06-07 | archive-date=2022-06-07 | archive-url=https://web.archive.org/web/20220607221430/https://www.energy.gov/sites/prod/files/2019/01/f58/Ultimate%20Fast%20Facts%20Guide-PRINT.pdf | url-status=live }}</ref> To generate the same amount of electricity annually (taking into account [[capacity factor]]s) from [[solar PV]] would require about {{convert|60|sqmi|km2}}, and from a wind farm about {{convert|310|sqmi|km2}}.{{ r | NEI_news_2015 | Energy_gov_Fast_Facts }} Not included in this, is land required for the associated transmission lines, water supply, rail lines, mining and processing of nuclear fuel, and for waste disposal.<ref>{{cite web|url=https://www.energy.gov/sites/prod/files/2017/03/f34/qtr-2015-chapter10.pdf|title=Quadrennial technology review concepts in integrated analysis|date=September 2015|page=388|access-date=2019-01-12|archive-date=2020-03-07|archive-url=https://web.archive.org/web/20200307173725/https://www.energy.gov/sites/prod/files/2017/03/f34/qtr-2015-chapter10.pdf|url-status=live}}</ref>

==Research==
===Advanced fission reactor designs===
{{Main|Generation IV reactor}}

Current fission reactors in operation around the world are [[generation II reactor|second]] or [[generation III reactor|third generation]] systems, with most of the first-generation systems having been already retired. Research into advanced [[generation IV reactor]] types was officially started by the Generation IV International Forum (GIF) based on eight technology goals, including to improve economics, safety, proliferation resistance, natural resource use and the ability to consume existing nuclear waste in the production of electricity. Most of these reactors differ significantly from current operating light water reactors, and are expected to be available for commercial construction after 2030.<ref>{{cite web |url=http://ossfoundation.us/projects/energy/nuclear |title=4th Generation Nuclear Power – OSS Foundation |publisher=Ossfoundation.us |access-date=2014-01-24 |archive-date=2014-02-01 |archive-url=https://web.archive.org/web/20140201171808/http://ossfoundation.us/projects/energy/nuclear }}</ref>

=== Hybrid fusion-fission ===
{{Main|Nuclear fusion–fission hybrid}}
Hybrid nuclear power is a proposed means of generating power by the use of a combination of nuclear fusion and fission processes. The concept dates to the 1950s and was briefly advocated by [[Hans Bethe]] during the 1970s, but largely remained unexplored until a revival of interest in 2009, due to delays in the realization of pure fusion. When a sustained nuclear fusion power plant is built, it has the potential to be capable of extracting all the fission energy that remains in spent fission fuel, reducing the volume of nuclear waste by orders of magnitude, and more importantly, eliminating all actinides present in the spent fuel, substances which cause security concerns.<ref name="hybrid">{{cite journal | author = Gerstner, E. | title = Nuclear energy: The hybrid returns | year = 2009 | journal = [[Nature (journal)|Nature]] | volume = 460 | issue = 7251 | pages = 25–28 | pmid = 19571861 | doi = 10.1038/460025a | s2cid = 205047403 | url = http://www.nature.com/news/2009/090701/pdf/460025a.pdf | doi-access = free | access-date = 2013-06-19 | archive-date = 2013-12-20 | archive-url = https://web.archive.org/web/20131220102840/http://www.nature.com/news/2009/090701/pdf/460025a.pdf | url-status = live }}</ref>

=== Fusion ===
[[File:U.S. Department of Energy - Science - 425 003 001 (9786811206).jpg|thumb|upright=1.2|Schematic of the [[ITER]] [[tokamak]] under construction in France]]
{{Main|Nuclear fusion|Fusion power}}
[[Fusion power|Nuclear fusion]] reactions have the potential to be safer and generate less radioactive waste than fission.<ref>{{cite book |last1=Roth |first1=J. Reece |title=Introduction to fusion energy |date=1986 |publisher=Ibis Pub |location=Charlottesville, Va. |isbn=978-0-935005-07-3}}</ref><ref name="WorldEnergyCouncil">{{cite web |last1=Hamacher |first1=T. |last2=Bradshaw |first2=A. M. |name-list-style=amp |date=October 2001 |title=Fusion as a Future Power Source: Recent Achievements and Prospects |url=http://www.worldenergy.org/wec-geis/publications/default/tech_papers/18th_Congress/downloads/ds/ds6/ds6_5.pdf |archive-url=https://web.archive.org/web/20040506065141/http://www.worldenergy.org/wec-geis/publications/default/tech_papers/18th_Congress/downloads/ds/ds6/ds6_5.pdf |archive-date=2004-05-06 |access-date=2010-09-16 |publisher=World Energy Council}}</ref> These reactions appear potentially viable, though technically quite difficult and have yet to be created on a scale that could be used in a functional power plant. Fusion power has been under theoretical and experimental investigation since the 1950s. [[Nuclear fusion]] research is underway but fusion energy is not likely to be commercially widespread before 2050.<ref>{{cite news |date=27 October 2019 |title=A lightbulb moment for nuclear fusion? |language=en |work=The Guardian |url=https://www.theguardian.com/environment/2019/oct/27/nuclear-fusion-research-power-generation-iter-jet-step-carbon-neutral-2050-boris-johnson |access-date=25 November 2021}}</ref><ref>{{cite journal |last1=Entler |first1=Slavomir |last2=Horacek |first2=Jan |last3=Dlouhy |first3=Tomas |last4=Dostal |first4=Vaclav |date=1 June 2018 |title=Approximation of the economy of fusion energy |journal=Energy |language=en |volume=152 |pages=489–497 |doi=10.1016/j.energy.2018.03.130 |s2cid=115968344 |issn=0360-5442|doi-access=free |bibcode=2018Ene...152..489E }}</ref><ref>{{cite journal |last1=Nam |first1=Hoseok |last2=Nam |first2=Hyungseok |last3=Konishi |first3=Satoshi |date=2021 |title=Techno-economic analysis of hydrogen production from the nuclear fusion-biomass hybrid system |journal=International Journal of Energy Research |language=en |volume=45 |issue=8 |pages=11992–12012 |doi=10.1002/er.5994 |issn=1099-114X |s2cid=228937388|doi-access=free |bibcode=2021IJER...4511992N }}</ref>

Several experimental nuclear fusion reactors and facilities exist. The largest and most ambitious international nuclear fusion project currently in progress is [[ITER]], a large [[tokamak]] under construction in France. ITER is planned to pave the way for commercial fusion power by demonstrating self-sustained nuclear fusion reactions with positive energy gain. Construction of the ITER facility began in 2007, but the project has run into many delays and budget overruns. The facility is now not expected to begin operations until the year 2034.<ref>{{cite web|title=ITER fusion reactor to see further delays, with operations pushed to 2034|url=https://arstechnica.com/science/2024/07/iters-timeline-for-fusion-stretched-out-even-further/|publisher=Ars Technica|author=Timmer |first=John |accessdate=24 October 2025|date=5 July 2024}}</ref> A follow on commercial nuclear fusion power station, [[DEMOnstration Power Station|DEMO]], has been proposed.<ref name="ITERorg">{{cite web |title=Beyond ITER |url=http://www.iter.org/Future-beyond.htm |archive-url=https://web.archive.org/web/20061107220145/http://www.iter.org/Future-beyond.htm |archive-date=2006-11-07 |access-date=2011-02-05 |website=The ITER Project |publisher=Information Services, Princeton Plasma Physics Laboratory}} – Projected fusion power timeline.</ref><ref name="EFDA_Activities">{{cite web|url=http://www.efda.org/about_efda/downloads/EFDAoverview.ppt |title=Overview of EFDA Activities |website=www.efda.org |publisher=[[European Fusion Development Agreement]] |archive-url=https://web.archive.org/web/20061001123645/http://www.efda.org/about_efda/downloads/EFDAoverview.ppt |archive-date=2006-10-01 |access-date=2006-11-11 }}</ref> There are also suggestions for a power plant based upon a different fusion approach, that of an [[inertial fusion power plant]].{{cn|date=August 2025}}

Fusion-powered electricity generation was initially believed to be readily achievable, as fission-electric power had been. However, the extreme requirements for continuous reactions and [[plasma containment]] led to projections being extended by several decades. In 2020, more than 80 years after [[Timeline of nuclear fusion#1930s|the first attempts]], commercialization of fusion power production was thought to be unlikely before 2050.<ref name="ITERorg" /><ref name="fusion2">{{cite news |title=A lightbulb moment for nuclear fusion? |url=https://www.theguardian.com/environment/2019/oct/27/nuclear-fusion-research-power-generation-iter-jet-step-carbon-neutral-2050-boris-johnson |access-date=25 November 2021 |work=The Guardian |date=27 October 2019 |language=en}}</ref><ref name="fusiongua">{{cite news |last1=Turrell |first1=Arthur |title=The race to give nuclear fusion a role in the climate emergency |url=https://www.theguardian.com/environment/2021/aug/28/the-race-to-give-nuclear-fusion-a-role-in-the-climate-emergency |access-date=26 November 2021 |work=The Guardian |date=28 August 2021 |language=en}}</ref><ref name="fusion3">{{cite journal |last1=Entler |first1=Slavomir |last2=Horacek |first2=Jan |last3=Dlouhy |first3=Tomas |last4=Dostal |first4=Vaclav |title=Approximation of the economy of fusion energy |journal=Energy |date=1 June 2018 |volume=152 |pages=489–497 |doi=10.1016/j.energy.2018.03.130 |s2cid=115968344 |language=en |issn=0360-5442|doi-access=free |bibcode=2018Ene...152..489E }}</ref><ref name="fusion4">{{cite journal |last1=Nam |first1=Hoseok |last2=Nam |first2=Hyungseok |last3=Konishi |first3=Satoshi |title=Techno-economic analysis of hydrogen production from the nuclear fusion-biomass hybrid system |journal=International Journal of Energy Research |date=2021 |volume=45 |issue=8 |pages=11992–12012 |doi=10.1002/er.5994 |s2cid=228937388 |language=en |issn=1099-114X|doi-access=free |bibcode=2021IJER...4511992N }}</ref>

To enhance and accelerate the development of fusion energy, the [[United States Department of Energy]] (DOE) granted $46 million to eight firms, including [[Commonwealth Fusion Systems]] and [[Tokamak Energy]] Inc, in 2023. This ambitious initiative aims to introduce pilot-scale fusion within a decade.<ref>{{cite press release |url=https://www.reuters.com/business/energy/us-announces-46-million-funds-eight-nuclear-fusion-companies-2023-05-31/ |title=US announces $46 million in funds to eight nuclear fusion companies |date=31 May 2023 |access-date=13 June 2023 |archive-date=9 June 2023 |archive-url=https://web.archive.org/web/20230609110155/https://www.reuters.com/business/energy/us-announces-46-million-funds-eight-nuclear-fusion-companies-2023-05-31/ |url-status=live }}</ref>

== See also ==
{{div col|colwidth=20em}}
* [[Atomic battery]]
* [[Nuclear marine propulsion]]
* [[Nuclear power by country]]
* [[Nuclear weapons debate]]
* [[Pro-nuclear energy movement]]
* [[Thorium-based nuclear power]]
* [[Uranium mining debate]]
* [[World energy supply and consumption]]
{{div col end}}
{{clear}}

== References ==
{{reflist}}

== Further reading ==
{{sister project|project=Wikiversity
|text=[[v:How things work college course/Nuclear power quizzes|Wikiversity quizzes on nuclear power]]}}
{{See also|List of books about nuclear issues|List of films about nuclear issues}}

{{refbegin |30em}}
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}}
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* {{cite journal |last1=Patterson |first1=Eann A. |last2=Taylor |first2=Richard J. |title=The commoditization of civil nuclear power |journal=[[Royal Society Open Science]] |date=2024 |volume=11 |issue=5 |article-number=240021 |doi=10.1098/rsos.240021 |pmid=39076811 |doi-access=free |pmc=11285846|bibcode=2024RSOS...1140021P }}
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{{refend}}

== External links ==
{{subject bar|auto=y|d=y|wikt=y|s=y|b=y|v=y|Energy|Nuclear technology}}
* [https://eia.gov U.S. Energy Information Administration]
* [https://thebulletin.org/2015/05/introducing-the-nuclear-fuel-cycle-cost-calculator/ Nuclear Fuel Cycle Cost Calculator] {{Webarchive|url=https://web.archive.org/web/20220711190939/https://thebulletin.org/2015/05/introducing-the-nuclear-fuel-cycle-cost-calculator/ |date=2022-07-11 }}

{{Nuclear power by country}}
{{Nuclear technology}}
{{Electricity generation}}
{{Natural resources}}

{{Authority control}}

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