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{{Nuclear weapons}}
{{Weapons of mass destruction}}

A '''nuclear weapon'''{{efn|Also known as an '''atom bomb''', '''atomic bomb''', '''nuclear bomb''', or '''nuclear warhead''', and colloquially as an '''A-bomb''', '''nuke''', or simply '''the Bomb'''}} is an [[explosive device]] that derives its destructive force from [[nuclear reaction]]s, either [[nuclear fission]] (fission or atomic bomb) or a combination of fission and [[nuclear fusion]] reactions ([[thermonuclear weapon]]{{efn|Also known colloquially as an '''H-bomb''' or Hydrogen Bomb}}), producing a [[nuclear explosion]]. Both bomb types release large quantities of [[energy]] from relatively small amounts of [[matter]].

Nuclear weapons have had [[Nuclear weapon yield|yield]]s between 10 tons (the [[W54]]) and 50 megatons for the [[Tsar Bomba]] (see [[TNT equivalent]]). Yields in the low kilotons can devastate cities. A thermonuclear weapon weighing as little as {{convert|600|lb|sigfig=2}} can release energy equal to more than 1.2 megatons of TNT (5.0 [[Petajoule|PJ]]).<ref name=nukearc>{{cite web |first=Carey |last=Sublette |url=https://nuclearweaponarchive.org/Usa/Weapons/Allbombs.html |title=Complete List of All U.S. Nuclear Weapons |website=Nuclear weapon archive |date=12 June 2020 |access-date=2021-03-18}}</ref> Apart from the blast, [[effects of nuclear weapons]] include extreme [[Thermal radiation|heat]] and [[ionizing radiation]], [[firestorm]]s, radioactive [[nuclear fallout]], an [[Nuclear electromagnetic pulse|electromagnetic pulse]], and a [[radar blackout]].

The first nuclear weapons were developed by the [[Nuclear weapons of the United States|United States]] in collaboration with the [[Nuclear weapons of the United Kingdom|United Kingdom]] and [[Canada and weapons of mass destruction|Canada]] during [[World War II]] in the [[Manhattan Project]]. Production requires a large scientific and industrial complex, primarily for the production of [[fissile material]], either from [[nuclear reactor]]s with [[nuclear reprocessing|reprocessing plants]] or from [[Enriched uranium|uranium enrichment]] facilities. Nuclear weapons have been used twice in [[war]], in the 1945 [[atomic bombings of Hiroshima and Nagasaki]] that killed between 150,000 and 246,000 people. [[Deterrence theory|Nuclear deterrence]], including [[mutually assured destruction]], aims to prevent [[nuclear warfare]] via the threat of unacceptable damage and the danger of escalation to [[nuclear holocaust]]. A [[nuclear arms race]] for weapons and their delivery systems was a defining component of the [[Cold War]].

[[Strategic nuclear weapon]]s are targeted against civilian, industrial, and military infrastructure, while [[tactical nuclear weapons]] are intended for battlefield use. Strategic weapons led to the development of dedicated [[intercontinental ballistic missile]]s, [[submarine-launched ballistic missile]], and nuclear [[strategic bomber]]s, collectively known as the [[nuclear triad]]. Tactical weapons options have included shorter-range ground-, air-, and sea-launched missiles, [[nuclear artillery]], [[atomic demolition munition]]s, [[nuclear torpedo]]es, and [[nuclear depth charge]]s, but they have become less salient since the end of the Cold War.

{{As of|2025}}, there are nine countries on the [[list of states with nuclear weapons]], and six more agree to [[nuclear sharing]]. Nuclear weapons are [[weapons of mass destruction]], and their control is a focus of [[international security]] through measures to prevent [[nuclear proliferation]], [[arms control]], or [[nuclear disarmament]]. The total from all stockpiles peaked at over 64,000 weapons in 1986,<ref name="w310">{{cite journal |last1=Kristensen |first1=Hans M. |last2=Norris |first2=Robert S. |date=2013 |title=Global nuclear weapons inventories, 1945–2013 |journal=Bulletin of the Atomic Scientists |volume=69 |issue=5 |pages=75–81 |doi=10.1177/0096340213501363 |bibcode=2013BuAtS..69e..75K |issn=0096-3402 |doi-access=free}}</ref> and is around 9,600 today.<ref name="b908">{{cite web |title=SIPRI Yearbook 2025, Summary |url=https://www.sipri.org/sites/default/files/2025-06/yb25_summary_en.pdf |access-date=2025-07-06}}</ref> Key international agreements and organizations include the [[Treaty on the Non-Proliferation of Nuclear Weapons]], the [[Comprehensive Nuclear-Test-Ban Treaty]] and [[Comprehensive Nuclear-Test-Ban Treaty Organization]], the [[International Atomic Energy Agency]], the [[Treaty on the Prohibition of Nuclear Weapons]], and [[nuclear-weapon-free zone]]s.

== Testing and deployment ==
Nuclear weapons have only twice been used in warfare, both times by the [[United States]] against [[Empire of Japan|Japan]] at the end of [[World War II]]. On August 6, 1945, the [[United States Army Air Forces]] (USAAF) detonated a [[uranium]] gun-type [[fission bomb]] nicknamed "[[Little Boy]]" over the Japanese city of [[Hiroshima]]; three days later, on August 9, the USAAF<ref>{{Cite web |title=The U S Army Air Forces in World War II |url=https://www.afhistory.af.mil/FAQs/Fact-Sheets/Article/458967/the-u-s-army-air-forces-in-world-war-ii/https://www.afhistory.af.mil/FAQs/Fact-Sheets/Article/458967/the-u-s-army-air-forces-in-world-war-ii/ |access-date=2023-11-27 |website=Air Force Historical Support Division |language=en-US }}{{dead link|date=March 2025|bot=medic}}{{cbignore|bot=medic}}</ref> detonated a [[plutonium]] implosion-type fission bomb nicknamed "[[Fat Man]]" over the Japanese city of [[Nagasaki]]. These bombings caused injuries that resulted in the deaths of approximately 200,000 [[civilian]]s and [[military personnel]].<ref>{{cite web |url=http://www.rerf.or.jp/general/qa_e/qa1.html |title=Frequently Asked Questions #1 |publisher=[[Radiation Effects Research Foundation]] |quote=total number of deaths is not known precisely ... acute (within two to four months) deaths ... Hiroshima ... 90,000–166,000 ... Nagasaki ... 60,000–80,000 |access-date=September 18, 2007 |url-status=dead |archive-url=https://web.archive.org/web/20070919143939/http://www.rerf.or.jp/general/qa_e/qa1.html |archive-date=September 19, 2007 }}</ref> The ethics of these bombings and their role in [[Surrender of Japan|Japan's surrender]] are to this day, still [[debate over the atomic bombings of Hiroshima and Nagasaki|subjects of debate]].

Since the [[atomic bombings of Hiroshima and Nagasaki]], nuclear weapons have been detonated over 2,000 times for [[nuclear weapons testing|testing]] and demonstration. Only [[list of states with nuclear weapons|a few nations]] possess such weapons or are suspected of seeking them. The only countries known to have detonated nuclear weapons—and acknowledge possessing them—are (chronologically by date of first test) the [[United States and weapons of mass destruction|United States]], the [[Soviet Union]] (succeeded as a nuclear power by [[Russia and weapons of mass destruction|Russia]]), the [[United Kingdom and weapons of mass destruction|United Kingdom]], [[France and weapons of mass destruction|France]], [[China and weapons of mass destruction|China]], [[India and weapons of mass destruction|India]], [[Pakistan and weapons of mass destruction|Pakistan]], and [[North Korea and weapons of mass destruction|North Korea]]. [[Israel and weapons of mass destruction|Israel]] is believed to possess nuclear weapons, though, in a [[policy of deliberate ambiguity]], it does not acknowledge having them.<ref name="nuclearweapons1">{{cite web |url=https://fas.org/programs/ssp/nukes/nuclearweapons/nukestatus.html |title=Federation of American Scientists: Status of World Nuclear Forces |publisher=Fas.org |access-date=December 29, 2012 |url-status=live |archive-url=https://web.archive.org/web/20130102173724/http://www.fas.org/programs/ssp/nukes/nuclearweapons/nukestatus.html |archive-date=January 2, 2013}}</ref><ref>{{cite web |url=https://fas.org/nuke/guide/israel/nuke/index.html |title=Nuclear Weapons – Israel |publisher=Fas.org |date=January 8, 2007 |access-date=December 15, 2010 |url-status=live |archive-url=https://web.archive.org/web/20101207122117/http://www.fas.org/nuke/guide/israel/nuke/index.html |archive-date=December 7, 2010}}</ref>{{efn|See also [[Mordechai Vanunu]]}} [[Germany]], [[Italy]], [[Turkey]], [[Belgium]], the [[Netherlands]], and [[Belarus]] are [[Nuclear sharing|nuclear weapons sharing]] states.<ref name="nuclearweapons1"/> [[South Africa]] is the only country to have [[South Africa and weapons of mass destruction|independently developed]] and then [[South Africa and weapons of mass destruction#Dismantling|renounced and dismantled]] its nuclear weapons.<ref name="Nuclear Threat Initiatives, South Africa (NTI South Africa)">{{cite web|last=Executive release|title=South African nuclear bomb|url=http://www.nti.org/country-profiles/south-africa/nuclear/|website=Nuclear Threat Initiatives|publisher=Nuclear Threat Initiatives, South Africa (NTI South Africa)|access-date=March 13, 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120928185925/http://www.nti.org/country-profiles/south-africa/nuclear/|archive-date=September 28, 2012}}</ref>

On the October 30, 2025, US President [[Donald Trump]] called for renewed nuclear weapons testing in order to keep pace with other nuclear armed states such as [[Russia]] and [[China]] however it was not specified whether he referred to [[Nuclear weapons testing|nuclear explosive testing]] or testing of [[Nuclear weapons delivery|delivery systems]] for nuclear warheads.<ref>[https://www.bbc.co.uk/news/articles/c4gzq2p0yk4o Trump directs nuclear weapons testing to resume for first time in over 30 years]</ref><ref>[https://www.theguardian.com/us-news/2025/oct/29/trump-pentagon-us-nuclear-weapons Trump directs Pentagon to match Russia and China in nuclear weapons testing]</ref>

{{First nuclear tests}}

== Types ==
{{Main|Nuclear weapon design}}
[[File:Trinity shot color.jpg|thumb|left|The [[Trinity (nuclear test)|Trinity test]] of the [[Manhattan Project]] was the first detonation of a nuclear weapon, which led [[J. Robert Oppenheimer]] to recall verses from the [[Hindu]] scripture ''[[Bhagavad Gita]]'': "If the radiance of a thousand suns were to burst at once into the sky, that would be like the splendor of the mighty one&nbsp;"... "I am become Death, the destroyer of worlds".{{sfn|Jungk|1958|p=201}}]]

There are two basic types of nuclear weapons: those that derive the majority of their energy from [[nuclear fission]] reactions alone, and those that use fission reactions to begin [[nuclear fusion]] reactions that produce a large amount of the total energy output.<ref name="Inc.1954">{{cite journal|author=Educational Foundation for Nuclear Science, Inc.|title=Bulletin of the Atomic Scientists|journal=Bulletin of the Atomic Scientists: Science and Public Affairs |url=https://books.google.com/books?id=rw0AAAAAMBAJ&pg=PA61|date=February 1954|publisher=Educational Foundation for Nuclear Science, Inc.|pages=61–|issn=0096-3402 |url-status=live |archive-url=https://web.archive.org/web/20170331041028/https://books.google.com/books?id=rw0AAAAAMBAJ&pg=PA61|archive-date=March 31, 2017}}</ref>

=== Fission weapons ===
[[File:Fission bomb assembly methods.svg|upright=1.4|thumb|The two basic [[Nuclear fission|fission]] weapon designs]]
All existing nuclear weapons derive some of their explosive energy from nuclear fission reactions. Weapons whose explosive output is exclusively from fission reactions are commonly referred to as '''atomic bombs''' or '''atom bombs''' (abbreviated as '''A-bombs'''). This has long been noted as something of a [[misnomer]], as their energy comes from the [[Atomic nucleus|nucleus]] of the atom, just as it does with fusion weapons.

In fission weapons, a mass of [[fissile material]] ([[enriched uranium]] or [[plutonium]]) is forced into [[critical mass|supercriticality]]—allowing an [[exponential growth]] of [[nuclear chain reaction]]s—either by shooting one piece of sub-critical material into another (the "gun" method) or by compression of a sub-critical sphere or cylinder of fissile material using chemically fueled [[explosive lens]]es. The latter approach, the "implosion" method, is more sophisticated and more efficient (smaller, less massive, and requiring less of the expensive fissile fuel) than the former.

A major challenge in all nuclear weapon designs is to ensure that a significant fraction of the fuel is consumed before the weapon destroys itself. The amount of energy released by fission bombs can range from the equivalent of just under a ton to upwards of 500,000 tons (500 [[kiloton]]s) of [[TNT]] ({{convert|1|to|5E5|tTNT|sigfig=2|disp=out}}).<ref name="Hansen">Hansen, Chuck. ''U.S. Nuclear Weapons: The Secret History.'' San Antonio, TX: Aerofax, 1988; and the more-updated Hansen, Chuck, "[http://www.uscoldwar.com/ Swords of Armageddon: U.S. Nuclear Weapons Development since 1945] {{webarchive |url=https://web.archive.org/web/20161230020259/http://www.uscoldwar.com/ |date=December 30, 2016}}" (CD-ROM & download available). PDF. 2,600 pages, Sunnyvale, California, Chuklea Publications, 1995, 2007. {{ISBN|978-0-9791915-0-3}} (2nd Ed.)</ref>

All fission reactions generate [[Nuclear fission product|fission products]], the remains of the split atomic nuclei. Many fission products are either highly [[Radioactive decay|radioactive]] (but short-lived) or moderately radioactive (but long-lived), and as such, they are a serious form of [[radioactive contamination]]. Fission products are the principal radioactive component of [[nuclear fallout]]. Another source of radioactivity is the burst of free neutrons produced by the weapon. When they collide with other nuclei in the surrounding material, the neutrons transmute those nuclei into other isotopes, altering their stability and making them radioactive.

The most commonly used fissile materials for nuclear weapons applications have been [[uranium-235]] and [[plutonium-239]]. Less commonly used has been [[uranium-233]]. [[Neptunium-237]] and some isotopes of [[americium]] may be usable for nuclear explosives as well, but it is not clear that this has ever been implemented, and their plausible use in nuclear weapons is a matter of dispute.<ref>{{cite web |last1=Albright |first1=David |author-link1=David Albright |last2=Kramer |first2=Kimberly |date=August 22, 2005 |title=Neptunium 237 and Americium: World Inventories and Proliferation Concerns |url=http://isis-online.org/uploads/isis-reports/documents/np_237_and_americium.pdf |publisher=[[Institute for Science and International Security]] |access-date=October 13, 2011 |url-status=live |archive-url=https://web.archive.org/web/20120103234833/http://isis-online.org/uploads/isis-reports/documents/np_237_and_americium.pdf |archive-date=January 3, 2012}}</ref>

=== Fusion weapons ===
{{Main|Thermonuclear weapon}}
[[File:Teller-Ulam device 3D.svg|thumb|The basics of the [[Teller–Ulam design]] for a hydrogen bomb: a fission bomb uses radiation to compress and heat a separate section of fusion fuel.]]

The other basic type of nuclear weapon produces a large proportion of its energy in nuclear fusion reactions. Such fusion weapons are generally referred to as '''[[thermonuclear weapon]]s''' or more colloquially as '''hydrogen bombs''' (abbreviated as '''H-bombs'''), as they rely on fusion reactions between isotopes of [[hydrogen]] ([[deuterium]] and [[tritium]]). All such weapons derive a significant portion of their energy from fission reactions used to "trigger" fusion reactions, and fusion reactions can themselves trigger additional fission reactions.<ref>Carey Sublette, [https://nuclearweaponarchive.org/Nwfaq/Nfaq4-5.html#Nfaq4.5.2 Nuclear Weapons Frequently Asked Questions: 4.5.2 "Dirty" and "Clean" Weapons] {{webarchive |url=https://web.archive.org/web/20160303170957/http://nuclearweaponarchive.org/Nwfaq/Nfaq4-5.html |date=March 3, 2016}}, accessed May 10, 2011.</ref>

Only six countries—the [[United States]], [[Russia]], the [[United Kingdom]], [[China]], [[France]], and [[India]]—have conducted thermonuclear weapon tests. Whether India has detonated a "true" multi-staged [[thermonuclear weapon]] is controversial.<ref>On India's alleged hydrogen bomb test, see Carey Sublette, [http://nuclearweaponarchive.org/India/IndiaRealYields.html What Are the Real Yields of India's Test?] {{webarchive |url=https://web.archive.org/web/20110927013551/http://nuclearweaponarchive.org/India/IndiaRealYields.html |date=September 27, 2011}}.</ref> [[North Korea]] claims to have tested a fusion weapon {{as of|2016|January|lc=y}}, though this claim is disputed.<ref>{{cite web|last=McKirdy|first=Euan|title=North Korea announces it conducted nuclear test |url=http://www.cnn.com/2016/01/05/asia/north-korea-seismic-event/|website=CNN|date=January 6, 2016|access-date=January 7, 2016 |url-status=live |archive-url=https://web.archive.org/web/20160107193043/http://www.cnn.com/2016/01/05/asia/north-korea-seismic-event/|archive-date=January 7, 2016}}</ref> Thermonuclear weapons are considered much more difficult to successfully design and execute than primitive fission weapons. Almost all of the nuclear weapons deployed today use the thermonuclear design because it results in an explosion hundreds of times stronger than that of a fission bomb of similar weight.<ref>{{Cite web |url=https://www.armscontrol.org/factsheets/Nuclear-Testing-and-Comprehensive-Test-Ban-Treaty-CTBT-Timeline|title=Nuclear Testing and Comprehensive Test Ban Treaty (CTBT) Timeline |website=Arms control association |url-status=dead |archive-url=https://web.archive.org/web/20200421174531/https://www.armscontrol.org/factsheets/Nuclear-Testing-and-Comprehensive-Test-Ban-Treaty-CTBT-Timeline|archive-date=April 21, 2020}}</ref>

Thermonuclear bombs work by using the energy of a fission bomb to compress and heat fusion fuel. In the [[Teller-Ulam design]], which accounts for all multi-megaton yield hydrogen bombs, this is accomplished by placing a fission bomb and fusion fuel ([[tritium]], [[deuterium]], or [[lithium deuteride]]) in proximity within a special, radiation-reflecting container. When the fission bomb is detonated, [[gamma ray]]s and [[X-ray]]s emitted first compress the fusion fuel, then heat it to thermonuclear temperatures. The ensuing fusion reaction creates enormous numbers of high-speed [[neutron]]s, which can then induce fission in materials not normally prone to it, such as [[depleted uranium]]. Each of these components is known as a "stage", with the fission bomb as the "primary" and the fusion capsule as the "secondary". In large, megaton-range hydrogen bombs, about half of the yield comes from the final fissioning of depleted uranium.<ref name="Hansen"/>

Virtually all thermonuclear weapons deployed today use this "two-stage" design, but it is possible to add additional fusion stages—each stage igniting a larger amount of fusion fuel in the next stage. This technique can be used to construct thermonuclear weapons of arbitrarily large yield. This is in contrast to fission bombs, which are limited in their explosive power due to [[Nuclear criticality safety|criticality]] danger (premature nuclear chain reaction caused by too-large amounts of pre-assembled fissile fuel). The largest nuclear weapon ever detonated, the [[Tsar Bomba]] of the USSR, which released an energy equivalent of over {{convert|50|MtonTNT}}, was a three-stage weapon. Most thermonuclear weapons are considerably smaller than this, due to practical constraints from missile warhead space and weight requirements.<ref name="Sublette">{{cite web |url=http://nuclearweaponarchive.org/ |last=Sublette |first=Carey |title=The Nuclear Weapon Archive |access-date=March 7, 2007 |url-status=live |archive-url=https://web.archive.org/web/20070301105632/http://nuclearweaponarchive.org/ |archive-date=March 1, 2007}}</ref> In the early 1950s the [[Lawrence Livermore National Laboratory|Livermore Laboratory]] in the United States had plans for the testing of two massive bombs, Gnomon and [[Sundial (weapon)|Sundial]], 1 gigaton of TNT and 10 gigatons of TNT respectively.<ref>{{Cite web |last=Simha |first=Rakesh Krishnan |date=2016-01-05 |title=Nuclear overkill: The quest for the 10 gigaton bomb |url=https://www.rbth.com/opinion/2016/01/05/nuclear-overkill-the-quest-for-the-10-gigaton-bomb_556351 |access-date=2023-10-08 |website=Russia Beyond |language=en-US |archive-date=November 29, 2023 |archive-url=https://web.archive.org/web/20231129191303/https://www.rbth.com/opinion/2016/01/05/nuclear-overkill-the-quest-for-the-10-gigaton-bomb_556351 |url-status=live }}</ref><ref>{{Cite web |last=Wellerstein |first=Alex |author-link=Alex Wellerstein |date=2021-10-29 |title=The untold story of the world's biggest nuclear bomb |url=https://thebulletin.org/2021/11/the-untold-story-of-the-worlds-biggest-nuclear-bomb/ |access-date=2023-10-08 |website=Bulletin of the Atomic Scientists |language=en-US |archive-date=August 27, 2023 |archive-url=https://web.archive.org/web/20230827130626/https://thebulletin.org/2021/11/the-untold-story-of-the-worlds-biggest-nuclear-bomb/ |url-status=live }}</ref>
[[File:Edward Teller (1958)-LLNL.jpg|thumb|upright|[[Edward Teller]], often referred to as the "father of the hydrogen bomb"]]

Fusion reactions do not create fission products, and thus contribute far less to the creation of [[nuclear fallout]] than fission reactions, but because all [[thermonuclear weapon]]s contain at least one [[Fission barrier|fission]] stage, and many high-yield thermonuclear devices have a final fission stage, thermonuclear weapons can generate at least as much nuclear fallout as fission-only weapons. Furthermore, high yield thermonuclear explosions (most dangerously ground bursts) have the force to lift radioactive debris upwards past the [[tropopause]] into the [[stratosphere]], where the calm non-turbulent winds permit the debris to travel great distances from the burst, eventually settling and unpredictably contaminating areas far removed from the target of the explosion.

=== Other types ===
{{Main|Boosted fission weapon|Neutron bomb|Radiological warfare|Induced gamma emission|Antimatter weapon}}
There are other types of nuclear weapons as well. For example, a [[boosted fission weapon]] is a fission bomb that increases its explosive yield through a small number of fusion reactions, but it is not a fusion bomb. In the boosted bomb, the neutrons produced by the fusion reactions serve primarily to increase the efficiency of the fission bomb. There are two types of boosted fission bomb: internally boosted, in which a deuterium-tritium mixture is injected into the bomb core, and externally boosted, in which concentric shells of lithium-deuteride and depleted uranium are layered on the outside of the fission bomb core. The external method of boosting enabled the [[USSR]] to field the first partially thermonuclear weapons, but it is now obsolete because it demands a spherical bomb geometry, which was adequate during the 1950s arms race when bomber aircraft were the only available delivery vehicles.

The detonation of any nuclear weapon is accompanied by a blast of [[neutron radiation]]. Surrounding a nuclear weapon with suitable materials (such as [[cobalt]] or [[gold]]) creates a weapon known as a [[salted bomb]]. This device can produce exceptionally large quantities of long-lived [[radioactive contamination]]. It has been conjectured that such a device could serve as a "doomsday weapon" because such a large quantity of radioactivities with half-lives of decades, lifted into the stratosphere where winds would distribute it around the globe, would make all life on the planet extinct.

In connection with the [[Strategic Defense Initiative]], research into the [[nuclear pumped laser]] was conducted under the DOD program [[Project Excalibur]] but this did not result in a working weapon. The concept involves the tapping of the energy of an exploding nuclear bomb to power a single-shot laser that is directed at a distant target.

During the [[Starfish Prime]] high-altitude nuclear test in 1962, an unexpected effect was produced which is called a [[nuclear electromagnetic pulse]]. This is an intense flash of electromagnetic energy produced by a rain of high-energy electrons which in turn are produced by a nuclear bomb's gamma rays. This flash of energy can permanently destroy or disrupt electronic equipment if insufficiently shielded. It has been proposed to use this effect to disable an enemy's military and civilian infrastructure as an adjunct to other nuclear or conventional military operations. By itself it could as well be useful to terrorists for crippling a nation's economic electronics-based infrastructure. Because the effect is most effectively produced by high altitude nuclear detonations (by military weapons delivered by air, though ground bursts also produce EMP effects over a localized area), it can produce damage to electronics over a wide, even continental, geographical area.<ref>{{Cite web |date=2021-07-15 |title=Why the U.S. once set off a nuclear bomb in space |url=https://www.nationalgeographic.com/premium/article/why-the-us-once-set-off-a-nuclear-bomb-in-space-called-starfish-prime |access-date=2023-11-27 |website=Premium |language=en |archive-date=November 29, 2023 |archive-url=https://web.archive.org/web/20231129191301/https://www.nationalgeographic.com/premium/article/why-the-us-once-set-off-a-nuclear-bomb-in-space-called-starfish-prime |url-status=live }}</ref>

Research has been done into the possibility of [[pure fusion weapon|pure fusion bombs]]: nuclear weapons that consist of fusion reactions without requiring a fission bomb to initiate them. Such a device might provide a simpler path to thermonuclear weapons than one that required the development of fission weapons first, and pure fusion weapons would create significantly less nuclear fallout than other thermonuclear weapons because they would not disperse fission products. In 1998, the [[United States Department of Energy]] divulged that the United States had, "...made a substantial investment" in the past to develop pure fusion weapons, but that, "The U.S. does not have and is not developing a pure fusion weapon", and that, "No credible design for a pure fusion weapon resulted from the DOE investment".<ref>{{cite web|author=U.S. Department of Energy|url= https://fas.org/sgp/othergov/doe/rdd-8.pdf|title= Restricted Data Declassification Decisions, 1946 to the Present (RDD-8)]|archive-url=https://web.archive.org/web/20150924140708/http://www.fas.org/sgp/othergov/doe/rdd-8.pdf |archive-date=September 24, 2015|access-date=November 20, 2011|date=January 1, 2002}}</ref>

[[Nuclear isomers]] provide a possible pathway to fissionless fusion bombs. These are naturally occurring [[isotopes]] ([[Isotopes of hafnium|<sup>178m2</sup>Hf]] being a prominent example) which exist in an elevated energy state. Mechanisms to release this energy as bursts of gamma radiation (as in the [[hafnium controversy]]) have been proposed as possible triggers for conventional thermonuclear reactions.

[[Antimatter]], which consists of [[particles]] resembling ordinary [[matter]] particles in most of their properties but having opposite [[electric charge]], has been considered as a trigger mechanism for nuclear weapons.<ref name="arxiv.org">{{cite arXiv|eprint=physics/0510071 |last=Gsponer |first=Andre |title=Fourth Generation Nuclear Weapons: Military effectiveness and collateral effects |year=2005 }}</ref><ref>{{cite web |url=http://www.nextbigfuture.com/2015/09/details-on-antimatter-triggered-fusion.html|title=Details on antimatter triggered fusion bombs |website=NextBigFuture.com|date=September 22, 2015 |url-status=live |archive-url=https://web.archive.org/web/20170422125419/http://www.nextbigfuture.com/2015/09/details-on-antimatter-triggered-fusion.html|archive-date=April 22, 2017}}</ref><ref>{{cite web |url=http://cui.unige.ch/isi/sscr/phys/anti-BPP-3.html |title=Page discussing the possibility of using antimatter as a trigger for a thermonuclear explosion |publisher=Cui.unige.ch |access-date=May 30, 2013 |url-status=live |archive-url=https://web.archive.org/web/20130424174413/http://cui.unige.ch/isi/sscr/phys/anti-BPP-3.html |archive-date=April 24, 2013}}</ref> A major obstacle is the difficulty of producing antimatter in large enough quantities, and there is no evidence that it is feasible beyond the military domain.<ref>{{Cite book |arxiv=physics/0507114 |last1=Gsponer |first1=Andre |last2=Hurni |first2=Jean-Pierre |chapter=The physics of antimatter induced fusion and thermonuclear explosions |editor1-first=G. |editor1-last=Velarde |editor2-first=E. |editor2-last=Minguez |title=Proceedings of the 4th International Conference on Emerging Nuclear Energy Systems, Madrid, June 30/July 4, 1986 |publisher=World Scientific, Singapore |year=1987 |pages=166–169}}</ref> However, the US Air Force funded studies of the physics of antimatter in the [[Cold War]], and began considering its possible use in weapons, not just as a trigger, but as the explosive itself.<ref>{{cite news |author1=Keay Davidson |author2=Chronicle Science Writer |url=http://sfgate.com/cgi-bin/article.cgi?file=/c/a/2004/10/04/MNGM393GPK1.DTL |title=Air Force pursuing antimatter weapons: Program was touted publicly, then came official gag order |publisher=Sfgate.com |date=October 4, 2004 |access-date=May 30, 2013 |url-status=live |archive-url=https://web.archive.org/web/20120609101650/http://www.sfgate.com/cgi-bin/article.cgi?file=%2Fc%2Fa%2F2004%2F10%2F04%2FMNGM393GPK1.DTL |archive-date=June 9, 2012}}</ref> A fourth generation nuclear weapon design<ref name="arxiv.org"/> is related to, and relies upon, the same principle as [[antimatter-catalyzed nuclear pulse propulsion]].<ref>{{cite web |url=http://nuclearweaponarchive.org/News/INESAPTR1.html|title=Fourth Generation Nuclear Weapons|access-date=October 24, 2014 |url-status=live |archive-url=https://web.archive.org/web/20160323010905/http://nuclearweaponarchive.org/News/INESAPTR1.html|archive-date=March 23, 2016}}</ref>

Most variation in [[nuclear weapon design]] is for the purpose of achieving [[Dial-a-yield|different yields for different situations]], and in manipulating design elements to attempt to minimize weapon size,<ref name="Hansen"/> [[Nuclear fratricide|radiation hardness]] or requirements for special materials, especially fissile fuel or tritium.

====Tactical nuclear weapons====
[[File:ChemicalExercise2018-01.jpg|thumb|right|Soviet [[OTR-21 Tochka]] missile. Capable of firing a 100-kiloton nuclear warhead a distance of 185 km]]
Some nuclear weapons are designed for special purposes; most of these are for non-strategic (decisively war-winning) purposes and are referred to as [[tactical nuclear weapon]]s.

The [[neutron bomb]] purportedly conceived by [[Samuel T. Cohen|Sam Cohen]] is a thermonuclear weapon that yields a relatively small explosion but a relatively large amount of neutron [[radiation]]. Such a weapon could, according to tacticians, be used to cause massive biological casualties while leaving inanimate infrastructure mostly intact and creating minimal fallout. Because high energy neutrons are capable of penetrating dense matter, such as tank armor, neutron warheads were procured in the 1980s (though not deployed in Europe) for use as tactical payloads for US Army artillery shells (200&nbsp;mm [[W79 Artillery-Fired Atomic Projectile|W79]] and 155&nbsp;mm [[W82]]) and [[MGM-52 Lance|short range missile]] forces. Soviet authorities announced similar intentions for neutron warhead deployment in Europe; indeed, they claimed to have originally invented the neutron bomb, but their deployment on USSR tactical nuclear forces is unverifiable.{{citation needed|date=May 2022}}

A type of nuclear explosive most suitable for use by ground special forces was the [[Special Atomic Demolition Munition]], or SADM, sometimes popularly known as a [[Suitcase nuclear device|suitcase nuke]]. This is a nuclear bomb that is man-portable, or at least truck-portable, and though of a relatively small yield (one or two kilotons) is sufficient to destroy important tactical targets such as bridges, dams, tunnels, important military or commercial installations, etc. either behind enemy lines or pre-emptively on friendly territory soon to be overtaken by invading enemy forces. These weapons require plutonium fuel and are particularly "dirty". They also demand especially stringent security precautions in their storage and deployment.{{citation needed|date=May 2022}}

Small "tactical" nuclear weapons were deployed for use as antiaircraft weapons. Examples include the USAF [[AIR-2 Genie]], the [[AIM-26 Falcon]] and US Army [[Nike Hercules]]. Missile interceptors such as the [[Sprint (missile)|Sprint]] and the [[LIM-49 Spartan|Spartan]] also used small nuclear warheads (optimized to produce neutron or X-ray flux) but were for use against enemy strategic warheads.{{citation needed|date=May 2022}}

Other small, or tactical, nuclear weapons were deployed by naval forces for use primarily as [[antisubmarine]] weapons. These included nuclear [[depth charge|depth bombs]] or nuclear armed torpedoes. Nuclear mines for use on land or at sea are also possibilities.{{citation needed|date=May 2022}}

== Weapons delivery ==
{{See also|Nuclear weapons delivery|Nuclear triad|Strategic bomber|Intercontinental ballistic missile|Submarine-launched ballistic missile}}
[[File:Fat Man (replica of nuclear bomb).jpg|right|thumb|The first nuclear weapons were [[gravity bomb]]s, such as the "[[Fat Man]]" weapon dropped on [[Nagasaki, Nagasaki|Nagasaki]], Japan. They were large and could only be delivered by [[heavy bomber]] aircraft]]
[[File:Dnepr rocket lift-off 1.jpg|left|thumb|upright|A demilitarized, [[Dnepr (rocket)|commercial launch]] of the Russian [[Strategic Rocket Forces]] R-36 [[ICBM]]; also known by the NATO reporting name: [[SS-18 Satan]]. Upon its first fielding in the late 1960s, the SS-18 remains the single highest [[throw weight]] missile delivery system ever built.]]

The system used to [[Nuclear weapons delivery|deliver]] a nuclear weapon to its target is an important factor affecting both [[nuclear weapon design]] and [[nuclear warfare|nuclear strategy]]. The design, development, and maintenance of delivery systems are among the most expensive parts of a nuclear weapons program; they account, for example, for 57% of the financial resources spent by the United States on nuclear weapons projects since 1940.<ref>Stephen I. Schwartz, ed., ''Atomic Audit: The Costs and Consequences of U.S. Nuclear Weapons Since 1940.'' Washington, D.C.: Brookings Institution Press, 1998. See also [http://www.brook.edu/fp/projects/nucwcost/figure1.htm Estimated Minimum Incurred Costs of U.S. Nuclear Weapons Programs, 1940–1996], an excerpt from the book. {{webarchive |url=https://web.archive.org/web/20081121144318/http://www.brook.edu/fp/projects/nucwcost/figure1.htm |date=November 21, 2008}}</ref>

The simplest method for delivering a nuclear weapon is a [[gravity bomb]] dropped from [[aircraft]]; this was the method used by the [[Atomic bombings of Hiroshima and Nagasaki|United States against Japan]] in 1945. This method places few restrictions on the size of the weapon. It does, however, limit attack range, response time to an impending attack, and the number of weapons that a country can field at the same time. With miniaturization, nuclear bombs can be delivered by both [[strategic bomber]]s and tactical [[fighter-bomber]]s. This method is the primary means of nuclear weapons delivery; the majority of US nuclear warheads, for example, are free-fall gravity bombs, namely the [[B61 nuclear bomb|B61]], which is being improved upon to this day.<ref name="Hansen"/><ref>{{Cite web |last=Mehta |first=Aaron |date=2023-10-27 |title=US to introduce new nuclear gravity bomb design: B61-13 |url=https://breakingdefense.sites.breakingmedia.com/2023/10/us-to-introduce-new-nuclear-gravity-bomb-design-b61-13/ |access-date=2023-11-27 |website=Breaking Defense |language=en-US |archive-date=December 17, 2023 |archive-url=https://web.archive.org/web/20231217083734/https://breakingdefense.com/2023/10/us-to-introduce-new-nuclear-gravity-bomb-design-b61-13/ |url-status=live }}</ref>

[[File:Trident C-4 montage.jpg|thumb|right|Montage of an inert test of a United States [[Trident missile|Trident]] [[SLBM]] (submarine launched ballistic missile), from submerged to the [[Missile defense#Terminal phase|terminal]], or re-entry phase, of the [[multiple independently targetable reentry vehicle]]s]]

Preferable from a strategic point of view is a nuclear weapon mounted on a [[missile]], which can use a [[Ballistics|ballistic]] trajectory to deliver the warhead over the horizon. Although even short-range missiles allow for a faster and less vulnerable attack, the development of long-range [[intercontinental ballistic missile]]s (ICBMs) and [[submarine-launched ballistic missile]]s (SLBMs) has given some nations the ability to plausibly deliver missiles anywhere on the globe with a high likelihood of success.

More advanced systems, such as [[multiple independently targetable reentry vehicle]]s (MIRVs), can launch multiple warheads at different targets from one missile, reducing the chance of a successful [[missile defense]]. Today, missiles are most common among systems designed for delivery of nuclear weapons. Making a warhead small enough to fit onto a missile, though, can be difficult.<ref name="Hansen"/>

[[Tactical nuclear weapon|Tactical weapons]] have involved the most variety of delivery types, including not only gravity bombs and missiles but also [[nuclear artillery|artillery]] shells, [[atomic demolition munition|land mines]], and [[nuclear depth charge]]s and [[nuclear torpedo|torpedoes]] for [[anti-submarine warfare]]. An atomic [[mortar (weapon)|mortar]] has been tested by the United States. Small, two-man portable tactical weapons (somewhat misleadingly referred to as [[suitcase bomb]]s), such as the [[Special Atomic Demolition Munition]], have been developed, although the difficulty of combining sufficient yield with portability limits their military utility.<ref name="Hansen"/>

== Nuclear strategy ==
{{Main|Nuclear strategy|Deterrence theory}}
{{See also|Pre-emptive nuclear strike|Nuclear peace|Essentials of Post–Cold War Deterrence|Single Integrated Operational Plan|Nuclear warfare|On Thermonuclear War}}
Nuclear warfare strategy is a set of policies that deal with preventing or fighting a nuclear war. The policy of trying to prevent an attack by a nuclear weapon from another country by threatening nuclear retaliation is known as the strategy of [[deterrence theory|nuclear deterrence]]. The goal in deterrence is to always maintain a second strike capability (the ability of a country to respond to a nuclear attack with one of its own) and potentially to strive for [[Pre-emptive nuclear strike|first strike]] status (the ability to destroy an enemy's nuclear forces before they could retaliate). During the Cold War, policy and military theorists considered the sorts of policies that might prevent a nuclear attack, and they developed [[game theory]] models that could lead to stable deterrence conditions.<ref name="Handel2012">{{cite book |url=https://books.google.com/books?id=Gp0rBgAAQBAJ&pg=PA85 | first=Michael I. | last=Handel |title=War, Strategy and Intelligence |date=November 12, 2012 |publisher=[[Routledge]] |isbn=978-1-136-28624-7 |pages=85 |archive-url=https://web.archive.org/web/20170331214605/https://books.google.com/books?id=Gp0rBgAAQBAJ&pg=PA85 |archive-date=March 31, 2017 |url-status=live}}</ref>

[[File:W87 MX Missile schematic.jpg|thumb|The now decommissioned United States' [[LG-118A Peacekeeper|Peacekeeper missile]] was an [[ICBM]] developed to replace the [[Minuteman missile]] in the late 1980s. Each missile, like the [[Throw weight|heavier lift]] Russian [[SS-18 Satan]], could contain up to ten nuclear warheads (shown in red), each of which could be aimed at a different target. A factor in the development of [[MIRV]]s was to make complete [[missile defense]] difficult for an enemy country.]]

Different forms of [[nuclear weapons delivery]] (see above) allow for different types of nuclear strategies. The goals of any strategy are generally to make it difficult for an enemy to launch a pre-emptive strike against the weapon system and difficult to defend against the delivery of the weapon during a potential conflict. This can mean keeping weapon locations hidden, such as deploying them on [[submarine]]s or land mobile [[transporter erector launcher]]s whose locations are difficult to track, or it can mean protecting weapons by burying them in hardened [[missile silo]] bunkers. Other components of nuclear strategies included using missile defenses to destroy the missiles before they land or implementing [[civil defense]] measures using early-warning systems to evacuate citizens to safe areas before an attack.

Weapons designed to threaten large populations or to deter attacks are known as ''[[strategic nuclear weapons|strategic weapons]].'' Nuclear weapons for use on a [[battle]]field in military situations are called ''[[tactical nuclear weapons|tactical weapons]].''

Critics of nuclear war strategy often suggest that a nuclear war between two nations would result in mutual annihilation. From this point of view, the significance of nuclear weapons is to deter war because any nuclear war would escalate out of mutual distrust and fear, resulting in [[mutually assured destruction]]. This threat of national, if not global, destruction has been a strong motivation for anti-nuclear weapons activism.

Critics from the peace movement and within the military establishment{{citation needed|date=June 2013}} have questioned the usefulness of such weapons in the current military climate. According to an [[International Court of Justice advisory opinion on the Legality of the Threat or Use of Nuclear Weapons|advisory opinion]] issued by the [[International Court of Justice]] in 1996, the use of (or threat of use of) such weapons would generally be contrary to the rules of international law applicable in armed conflict, but the court did not reach an opinion as to whether or not the threat or use would be lawful in specific extreme circumstances such as if the survival of the state were at stake.

[[File:180326-N-UK333-189 (41145118741).jpg|right|thumb|[[Ballistic missile submarine]]s have been of great strategic importance for the United States, Russia, and other nuclear powers since they entered service in the [[Cold War]], as they can hide from [[reconnaissance satellite]]s and fire their nuclear weapons with virtual impunity.]]
Another [[deterrence theory|deterrence]] position is that [[nuclear proliferation]] can be desirable. In this case, it is argued that, unlike conventional weapons, nuclear weapons deter all-out war between states, and they succeeded in doing this during the [[Cold War]] between the US and the [[Soviet Union]].<ref>{{cite book |last=Creveld |first=Martin Van |title=The Oxford History of Modern War |chapter=Technology and War II:Postmodern War? |editor-last=Townshend |editor-first=Charles |publisher=[[Oxford University Press]] |year=2000 |location=New York |page=[https://archive.org/details/oxfordhistoryofm00town/page/349 349] |isbn=978-0-19-285373-8 |chapter-url=https://archive.org/details/oxfordhistoryofm00town |url=https://archive.org/details/oxfordhistoryofm00town/page/349}}</ref> In the late 1950s and early 1960s, Gen. [[Pierre Marie Gallois]] of France, an adviser to [[Charles de Gaulle]], argued in books like ''The Balance of Terror: Strategy for the Nuclear Age'' (1961) that mere possession of a nuclear arsenal was enough to ensure deterrence, and thus concluded that the spread of nuclear weapons could increase [[Nuclear peace|international stability]]. Some prominent [[Neorealism (international relations)|neo-realist]] scholars, such as [[Kenneth Waltz]] and [[John Mearsheimer]], have argued, along the lines of Gallois, that some forms of nuclear proliferation would decrease the likelihood of [[total war]], especially in troubled regions of the world where there exists a single nuclear-weapon state. Aside from the public opinion that opposes proliferation in any form, there are two schools of thought on the matter: those, like Mearsheimer, who favored selective proliferation,<ref>{{Cite journal |last=Mearsheimer |first=John |year=2006 |title=Conversations in International Relations: Interview with John J. Mearsheimer (Part I) |url=http://jonmearsheimer.uchicago.edu/pdfs/A0020.pdf |url-status=dead |journal=International Relations |volume=20 |issue=1 |pages=105–123 |doi=10.1177/0047117806060939 |s2cid=220788933 |archive-url=https://web.archive.org/web/20130501181414/http://johnmearsheimer.uchicago.edu/pdfs/A0020.pdf |archive-date=May 1, 2013 |access-date=November 23, 2020 |issn = 0047-1178 }} See page 116</ref> and Waltz, who was somewhat more non-[[interventionism (politics)|interventionist]].<ref>Kenneth Waltz, "More May Be Better", in Scott Sagan and Kenneth Waltz, eds., ''The Spread of Nuclear Weapons'' (New York: Norton, 1995).</ref><ref name=waltz>Kenneth Waltz, [http://www.mtholyoke.edu/acad/intrel/waltz1.htm "The Spread of Nuclear Weapons: More May Better"], {{webarchive |url=https://web.archive.org/web/20101201053554/http://www.mtholyoke.edu/acad/intrel/waltz1.htm |date=December 1, 2010}} ''Adelphi Papers'', no. 171 (London: International Institute for Strategic Studies, 1981).</ref> Interest in proliferation and the [[stability-instability paradox]] that it generates continues to this day, with ongoing debate about indigenous Japanese and [[South Korea]]n nuclear deterrent against [[North Korea]].<ref>{{cite web |url=http://www.strategicstudiesinstitute.army.mil/pubs/display.cfm?pubID=1327|title=Should We Let the Bomb Spread? Edited by Mr. Henry D. Sokolski. Strategic studies institute. November 2016 |url-status=dead |archive-url=https://web.archive.org/web/20161123214604/http://www.strategicstudiesinstitute.army.mil/pubs/display.cfm?pubID=1327|archive-date=November 23, 2016}}</ref>

The threat of potentially suicidal terrorists possessing nuclear weapons (a form of [[nuclear terrorism]]) complicates the decision process. The prospect of [[mutually assured destruction]] might not deter an enemy who expects to die in the confrontation. Further, if the initial act is from a stateless [[terrorist]] instead of a sovereign nation, there might not be a nation or specific target to retaliate against. It has been argued, especially after the [[September 11 attacks|September 11, 2001, attacks]], that this complication calls for a new nuclear strategy, one that is distinct from that which gave relative stability during the Cold War.<ref name="feldman">{{Cite news |date=2006-10-29 |title=Islam, Terror and the Second Nuclear Age (Published 2006) |url=https://www.nytimes.com/2006/10/29/magazine/islam-terror-and-the-second-nuclear-age.html |access-date=2025-08-30 |language=en}}</ref> Since 1996, the United States has had a policy of allowing the targeting of its nuclear weapons at terrorists armed with [[weapons of mass destruction]].<ref>{{Cite book |url=https://books.google.com/books?id=sgsAAAAAMBAJ |title=Bulletin of the Atomic Scientists |date=November 1998 |publisher=Educational Foundation for Nuclear Science |language=en}}</ref>

[[File:Minuteman III launches from Vandenberg (2425138).jpg|thumb|A [[LGM-30 Minuteman|Minuteman III]] ICBM test launch from [[Vandenberg Air Force Base]], United States. [[MIRV]]ed land-based [[ICBM]]s are considered destabilizing because they tend to put a premium on [[First strike (nuclear strategy)|striking first]].]]

[[Robert Gallucci]] argues that although traditional deterrence is not an effective approach toward terrorist groups bent on causing a nuclear catastrophe, Gallucci believes that "the United States should instead consider a policy of expanded deterrence, which focuses not solely on the would-be nuclear terrorists but on those states that may deliberately transfer or inadvertently leak nuclear weapons and materials to them. By threatening retaliation against those states, the United States may be able to deter that which it cannot physically prevent."<ref>{{cite journal|last=Gallucci|first=Robert|s2cid=68857650|title=Averting Nuclear Catastrophe: Contemplating Extreme Responses to U.S. Vulnerability|journal=Annals of the American Academy of Political and Social Science|date=September 2006|volume=607|pages=51–58|doi=10.1177/0002716206290457}}</ref>

[[Graham Allison]] makes a similar case, arguing that the key to expanded deterrence is coming up with ways of tracing nuclear material to the country that forged the fissile material. "After a nuclear bomb detonates, [[nuclear forensics]] cops would collect debris samples and send them to a laboratory for radiological analysis. By identifying unique attributes of the fissile material, including its impurities and contaminants, one could trace the path back to its origin." The process is analogous to identifying a criminal by fingerprints. "The goal would be twofold: first, to deter leaders of nuclear states from selling weapons to terrorists by holding them accountable for any use of their weapons; second, to give leaders every incentive to tightly secure their nuclear weapons and materials."<ref name="Allison">{{cite news |last=Allison |first=Graham |date=March 13, 2009 |title=How to Keep the Bomb From Terrorist s |url=http://www.thedailybeast.com/newsweek/2009/03/13/how-to-keep-the-bomb-from-terrorists.html |url-status=dead |archive-url=https://web.archive.org/web/20130513111324/http://www.thedailybeast.com/newsweek/2009/03/13/how-to-keep-the-bomb-from-terrorists.html |archive-date=May 13, 2013 |access-date=January 28, 2013 |newspaper=Newsweek}}</ref>

According to the Pentagon's June 2019 "[[Doctrine for Joint Nuclear Operations]]" of the Joint Chiefs of Staffs website Publication, "Integration of nuclear weapons employment with conventional and special operations forces is essential to the success of any mission or operation."<ref>{{cite news |title=The Pentagon Revealed Its Nuclear War Strategy and It's Terrifying |url=https://www.vice.com/en/article/the-pentagon-revealed-its-nuclear-war-strategy-and-its-terrifying/ |work=[[Vice (magazine)|Vice]] |date=June 21, 2019 |access-date=October 9, 2019 |archive-date=December 7, 2019 |archive-url=https://web.archive.org/web/20191207063100/https://www.vice.com/en_ca/article/mb84db/the-pentagon-revealed-its-nuclear-war-strategy-and-its-terrifying |url-status=live }}</ref><ref>{{cite news |title=Nuclear weapons: experts alarmed by new Pentagon 'war-fighting' doctrine |url=https://www.theguardian.com/world/2019/jun/19/nuclear-weapons-pentagon-us-military-doctrine |work=The Guardian |date=June 19, 2019 |access-date=October 9, 2019 |archive-date=June 19, 2019 |archive-url=https://web.archive.org/web/20190619222056/https://www.theguardian.com/world/2019/jun/19/nuclear-weapons-pentagon-us-military-doctrine |url-status=live }}</ref>

== Governance, control, and law ==
{{Main|International Atomic Energy Agency|Treaty on the Non-Proliferation of Nuclear Weapons|Strategic Arms Limitation Talks|Intermediate-Range Nuclear Forces Treaty|START I|START II|Strategic Offensive Reductions Treaty|Comprehensive Nuclear-Test-Ban Treaty|Lahore Declaration|New START|Treaty on the Prohibition of Nuclear Weapons}}
{{See also|Anti-nuclear movement}}

Because they are weapons of mass destruction, the proliferation and possible use of nuclear weapons are important issues in international relations and diplomacy. In most countries, the use of nuclear force can only be authorized by the [[head of government]] or [[head of state]].{{efn|In the United States, the President and the Secretary of Defense, acting as the [[National Command Authority (United States)|National Command Authority]], must ''jointly'' authorize the use of nuclear weapons.}} Despite controls and regulations governing nuclear weapons, there is an inherent danger of "accidents, mistakes, false alarms, blackmail, theft, and sabotage".<ref>[[Eric Schlosser]], [http://bos.sagepub.com/content/71/6/11.full Today's nuclear dilemma] {{Webarchive|url=https://web.archive.org/web/20160101090600/http://bos.sagepub.com/content/71/6/11.full |date=January 1, 2016 }}, ''[[Bulletin of the Atomic Scientists]]'', November/December 2015, vol. 71 no. 6, 11–17.</ref>

In the late 1940s, lack of mutual trust prevented the United States and the Soviet Union from making progress on arms control agreements. The [[Russell–Einstein Manifesto]] was issued in [[London]] on July 9, 1955, by [[Bertrand Russell]] in the midst of the Cold War. It highlighted the dangers posed by nuclear weapons and called for world leaders to seek peaceful resolutions to international conflict. The signatories included eleven pre-eminent intellectuals and scientists, including [[Albert Einstein]], who signed it just days before his death on April 18, 1955. A few days after the release, philanthropist [[Cyrus S. Eaton]] offered to sponsor a conference—called for in the manifesto—in [[Pugwash, Nova Scotia]], Eaton's birthplace. This conference was to be the first of the [[Pugwash Conferences on Science and World Affairs]], held in July 1957.

By the 1960s, steps were taken to limit both the proliferation of nuclear weapons to other countries and the environmental effects of [[nuclear testing]]. The [[Partial Nuclear Test Ban Treaty]] (1963) restricted all nuclear testing to [[underground nuclear testing]], to prevent contamination from nuclear fallout, whereas the [[Treaty on the Non-Proliferation of Nuclear Weapons]] (1968) attempted to place restrictions on the types of activities signatories could participate in, with the goal of allowing the transference of non-military [[nuclear technology]] to member countries without fear of proliferation.

[[File:Treaty on the Prohibition of Nuclear Weapons.svg|thumb|UN vote on adoption of the [[Treaty on the Prohibition of Nuclear Weapons]] on July 7, 2017<br/>{{Leftlegend|#008cff|Yes}} {{Leftlegend|#ff0000|No}}{{Leftlegend|#c0c0c0|Did not vote}}]]
In 1957, the [[International Atomic Energy Agency]] (IAEA) was established under the mandate of the [[United Nations]] to encourage development of peaceful applications of nuclear technology, provide international safeguards against its misuse, and facilitate the application of safety measures in its use. In 1996, many nations signed the [[Comprehensive Nuclear-Test-Ban Treaty]],<ref name=status/> which prohibits all testing of nuclear weapons. A testing ban imposes a significant hindrance to nuclear arms development by any complying country.<ref name="Richelson">Richelson, Jeffrey. ''Spying on the bomb: American nuclear intelligence from Nazi Germany to Iran and North Korea.'' New York: Norton, 2006.</ref> The Treaty requires the ratification by 44 specific states before it can go into force; {{as of|2012|lc=y}}, the ratification of eight of these states is still required.<ref name=status>Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (2010). "[http://www.ctbto.org/the-treaty/status-of-signature-and-ratification Status of Signature and Ratification] {{webarchive |url=https://web.archive.org/web/20110406151906/http://www.ctbto.org/the-treaty/status-of-signature-and-ratification/ |date=April 6, 2011}}". Accessed May 27, 2010. Of the "Annex 2" states whose ratification of the CTBT is required before it enters into force, China, Egypt, Iran, Israel, and the United States have signed but not ratified the Treaty. India, North Korea, and Pakistan have not signed the Treaty.</ref>

Additional treaties and agreements have governed nuclear weapons stockpiles between the countries with the two largest stockpiles, the United States and the Soviet Union, and later between the United States and Russia. These include treaties such as [[SALT II]] (never ratified), [[START I]] (expired), [[Intermediate-Range Nuclear Forces Treaty|INF]], [[START II]] (never in effect), [[SORT]], and [[New START]], as well as non-binding agreements such as [[SALT I]] and the Presidential Nuclear Initiatives<ref>[http://www.armscontrol.org/factsheets/pniglance The Presidential Nuclear Initiatives (PNIs) on Tactical Nuclear Weapons At a Glance] {{webarchive |url=https://web.archive.org/web/20110119164340/http://www.armscontrol.org/factsheets/pniglance |date=January 19, 2011}}, Fact Sheet, Arms Control Association.</ref> of 1991. Even when they did not enter into force, these agreements helped limit and later reduce the numbers and types of nuclear weapons between the United States and the Soviet Union/Russia.

Nuclear weapons have also been opposed by agreements between countries. Many nations have been declared [[Nuclear-Weapon-Free Zone]]s, areas where nuclear weapons production and deployment are prohibited, through the use of treaties. The [[Treaty of Tlatelolco]] (1967) prohibited any production or deployment of nuclear weapons in [[Latin America]] and the [[Caribbean]], and the [[Treaty of Pelindaba]] (1964) prohibits nuclear weapons in many African countries. As recently as 2006 a [[Central Asian Nuclear Weapon Free Zone]] was established among the former Soviet republics of Central Asia prohibiting nuclear weapons. [[File:Nuke-world-map-2024.png|thumb|The number of nuclear warheads by country in 2024, based on an estimation by the [[Federation of American Scientists]]]]

In 1996, the [[International Court of Justice]], the highest court of the United Nations, issued an Advisory Opinion concerned with the "[[International Court of Justice advisory opinion on the Legality of the Threat or Use of Nuclear Weapons|Legality of the Threat or Use of Nuclear Weapons]]". The court ruled that the use or threat of use of nuclear weapons would violate various articles of [[international law]], including the [[Geneva Conventions]], the [[Hague Conventions (1899 and 1907)|Hague Conventions]], the [[UN Charter]], and the [[Universal Declaration of Human Rights]]. Given the unique, destructive characteristics of nuclear weapons, the [[International Committee of the Red Cross]] calls on States to ensure that these weapons are never used, irrespective of whether they consider them lawful or not.<ref>[http://www.icrc.org/web/eng/siteeng0.nsf/htmlall/section_ihl_nuclear_weapons Nuclear weapons and international humanitarian law] {{webarchive |url=https://web.archive.org/web/20100421062555/http://www.icrc.org/web/eng/siteeng0.nsf/htmlall/section_ihl_nuclear_weapons |date=April 21, 2010}} International Committee of the Red Cross</ref>

Additionally, there have been other, specific actions meant to discourage countries from developing nuclear arms. In the wake of the tests by India and Pakistan in 1998, economic sanctions were (temporarily) levied against both countries, though neither were signatories with the Nuclear Non-Proliferation Treaty. One of the stated ''[[casus belli]]'' for the initiation of the 2003 [[Iraq War]] was an accusation by the United States that Iraq was actively pursuing nuclear arms (though this was soon discovered [[Niger uranium forgeries|not to be the case]] as the program had been discontinued). In 1981, Israel had [[Operation Opera|bombed a nuclear reactor]] being constructed in [[Osirak]], [[Iraq]], in what it called an attempt to halt Iraq's previous nuclear arms ambitions; in 2007, Israel [[Operation Orchard|bombed another reactor]] being constructed in [[Syria]].

In 2013, [[Mark Diesendorf]] said that governments of France, India, North Korea, Pakistan, UK, and South Africa have used nuclear power or research reactors to assist nuclear weapons development or to contribute to their supplies of nuclear explosives from military reactors.<ref name=diesrev>{{cite web |url=http://www.ies.unsw.edu.au/sites/all/files/MD%20BookReview_EnergyPolicy2013.pdf |title=Book review: Contesting the future of nuclear power |author=Mark Diesendorf |year=2013 |website=Energy Policy |url-status=dead |archive-url=https://web.archive.org/web/20130927163154/http://www.ies.unsw.edu.au/sites/all/files/MD%20BookReview_EnergyPolicy2013.pdf |archive-date=September 27, 2013 |author-link=Mark Diesendorf |access-date=July 9, 2013}}{{dubious|date=July 2013}}</ref> In 2017, 122 countries mainly in the [[Global South]] voted in favor of adopting the [[Treaty on the Prohibition of Nuclear Weapons]], which eventually entered into force in 2021.<ref>{{Cite web |title=History of the TPNW |url=https://www.icanw.org/history_of_the_tpnw |access-date=2023-06-05 |website=ICAN |language=en |archive-date=June 5, 2023 |archive-url=https://web.archive.org/web/20230605172312/https://www.icanw.org/history_of_the_tpnw |url-status=live }}</ref>

The [[Doomsday Clock]] measures the likelihood of a human-made [[Global catastrophic risk|global catastrophe]] and is published annually by the [[Bulletin of the Atomic Scientists]]. The Doomsday Clock is set a certain time from midnight, midnight being the time of global catastrophe. The two years with the highest likelihood had previously been 1953, when the Clock was set to two minutes until midnight after the US and the Soviet Union began testing hydrogen bombs, and 2018, following the failure of world leaders to address tensions relating to nuclear weapons and climate change issues.<ref>{{cite news|url=https://www.cnn.com/2018/01/25/politics/doomsday-clock-closer-nuclear-midnight/index.html|title='Doomsday clock' ticks closer to apocalyptic midnight|last=Koran|first=Laura|work=[[CNN]]|date=January 25, 2018|access-date=November 3, 2019|archive-date=November 3, 2019|archive-url=https://web.archive.org/web/20191103111015/https://www.cnn.com/2018/01/25/politics/doomsday-clock-closer-nuclear-midnight/index.html|url-status=live}}</ref> In 2023, following the [[Nuclear threats during the Russian invasion of Ukraine|escalation of nuclear threats]] during the [[Russian invasion of Ukraine]], the doomsday clock was set to 90 seconds, the highest likelihood of global catastrophe since the existence of the Doomsday Clock.<ref>{{Cite web |last=Spinazze |first=Gayle |date=2023-01-24 |title=PRESS RELEASE: Doomsday Clock set at 90 seconds to midnight |url=https://thebulletin.org/2023/01/press-release-doomsday-clock-set-at-90-seconds-to-midnight/ |access-date=2023-06-05 |website=Bulletin of the Atomic Scientists |language=en-US |archive-date=January 24, 2023 |archive-url=https://web.archive.org/web/20230124152126/https://thebulletin.org/2023/01/press-release-doomsday-clock-set-at-90-seconds-to-midnight/ |url-status=live }}</ref> Given the lack of progress towards peace in Ukraine, the Doomsday Clock was moved to 89 Seconds to midnight in 2025.<ref>{{Cite web |title=2025 Doomsday Clock Statement |url=https://thebulletin.org/doomsday-clock/2025-statement/ |access-date=2025-08-30 |website=Bulletin of the Atomic Scientists |language=en-US}}</ref>

As of 2024, Russia has intensified nuclear threats in Ukraine and is reportedly planning to place nuclear weapons in orbit, breaching the [[Outer Space Treaty|1967 Outer Space Treaty]]. China is significantly expanding its nuclear arsenal, with projections of over 1,000 warheads by 2030 and up to 1,500 by 2035. North Korea is progressing in intercontinental ballistic missile tests and has a mutual-defense treaty with Russia, exchanging artillery for possible missile technology. Iran is currently viewed as a nuclear "threshold" state.<ref>{{Cite news |date=12 August 2024 |title=America prepares for a new nuclear-arms race |url=https://www.economist.com/united-states/2024/08/12/america-prepares-for-a-new-nuclear-arms-race |access-date=2024-08-13 |newspaper=The Economist |issn=0013-0613}}</ref>

=== Disarmament ===
{{Main|Nuclear disarmament}}
{{for|statistics on possession and deployment|List of states with nuclear weapons}}
[[File:US and USSR nuclear stockpiles.svg|thumb|left|The [[USSR]] and United States nuclear weapon stockpiles throughout the [[Cold War]] until 2015, with a precipitous drop in total numbers following the end of the Cold War in 1991.]]

Nuclear disarmament refers to both the act of reducing or eliminating nuclear weapons and to the end state of a nuclear-free world, in which nuclear weapons are eliminated.

Beginning with the 1963 [[Partial Test Ban Treaty]] and continuing through the 1996 [[Comprehensive Nuclear-Test-Ban Treaty]], there have been many treaties to limit or reduce nuclear weapons testing and stockpiles. The 1968 [[Nuclear Non-Proliferation Treaty]] has as one of its explicit conditions that all signatories must "pursue negotiations in good faith" towards the long-term goal of "complete disarmament". The nuclear-weapon states have largely treated that aspect of the agreement as "decorative" and without force.<ref>Gusterson, Hugh, "[http://www.thebulletin.org/web-edition/columnists/hugh-gusterson/finding-article-vi Finding Article VI] {{webarchive |url=https://web.archive.org/web/20080917225812/http://www.thebulletin.org/web-edition/columnists/hugh-gusterson/finding-article-vi |date=September 17, 2008}}" ''Bulletin of the Atomic Scientists'' (January 8, 2007).</ref>

Only one country—South Africa—has ever fully renounced nuclear weapons they had independently developed. The former Soviet republics of [[Belarus]], [[Kazakhstan]], and [[Ukraine]] returned Soviet nuclear arms stationed in their countries to Russia after the [[collapse of the USSR]].

Proponents of nuclear disarmament say that it would lessen the probability of nuclear war, especially accidentally. Critics of nuclear disarmament say that it would undermine the present [[nuclear peace]] and deterrence and would lead to increased global instability. Various American elder statesmen,<ref>{{cite news |url=https://www.washingtonpost.com/opinions/nuclear-energy-after-fukushima/2011/10/05/gIQAbxIFRL_story.html |title=Nuclear energy after Fukushima |author=Jim Hoagland |date=October 6, 2011 |newspaper=[[The Washington Post]] |url-status=live |archive-url=https://web.archive.org/web/20131001011125/http://articles.washingtonpost.com/2011-10-06/opinions/35279184_1_nuclear-weapons-nuclear-power-nuclear-energy |archive-date=October 1, 2013 |access-date=September 6, 2017 }}</ref> who were in office during the [[Cold War]] period, have been advocating the elimination of nuclear weapons. These officials include [[Henry Kissinger]], [[George Shultz]], [[Sam Nunn]], and [[William J. Perry|William Perry]]. In January 2010, [[Lawrence M. Krauss]] stated that "no issue carries more importance to the long-term health and security of humanity than the effort to reduce, and perhaps one day, rid the world of nuclear weapons".<ref>Lawrence M. Krauss. The Doomsday Clock Still Ticks, ''Scientific American'', January 2010, p. 26.</ref>

[[File:SS-24 silo destruction.jpg|right|thumb|[[Ukraine|Ukrainian]] workers use equipment provided by the US [[Defense Threat Reduction Agency]] to dismantle a Soviet-era missile silo. After the end of the Cold War, Ukraine and the other non-Russian, post-Soviet republics relinquished Soviet nuclear stockpiles to Russia.]]

In January 1986, Soviet leader [[Mikhail Gorbachev]] publicly proposed a three-stage program for abolishing the world's nuclear weapons by the end of the 20th century.<ref>{{cite book |first=William |last=Taubman |year=2017 |title=Gorbachev: His Life and Times |location=New York City |publisher=[[Simon and Schuster]] |isbn=978-1-4711-4796-8 |page=291}}</ref> In the years after the end of the Cold War, there have been numerous campaigns to urge the abolition of nuclear weapons, such as that organized by the [[Global Zero (campaign)|Global Zero]] movement, and the goal of a "world without nuclear weapons" was advocated by United States President [[Barack Obama]] in an April 2009 speech in [[Prague]].<ref>{{cite news |url=https://www.huffingtonpost.com/2009/04/05/obama-prague-speech-on-nu_n_183219.html |title=Obama Prague Speech On Nuclear Weapons |publisher=Huffingtonpost.com |date=April 5, 2009 |access-date=May 30, 2013 |first=Nick |last=Graham |url-status=live |archive-url=https://web.archive.org/web/20130509130409/http://www.huffingtonpost.com/2009/04/05/obama-prague-speech-on-nu_n_183219.html |archive-date=May 9, 2013}}</ref> A [[CNN]] poll from April 2010 indicated that the American public was nearly evenly split on the issue.<ref>{{cite news |url=http://politicalticker.blogs.cnn.com/2010/04/12/cnn-poll-public-divided-on-eliminating-all-nuclear-weapons/ |title=CNN Poll: Public divided on eliminating all nuclear weapons |publisher=Politicalticker.blogs.cnn.com |date=April 12, 2010 |access-date=May 30, 2013 |url-status=dead |archive-url=https://web.archive.org/web/20130721061030/http://politicalticker.blogs.cnn.com/2010/04/12/cnn-poll-public-divided-on-eliminating-all-nuclear-weapons/ |archive-date=July 21, 2013 }}</ref>

Some analysts have argued that nuclear weapons have made the world relatively safer, with peace through [[deterrence theory|deterrence]] and through the [[stability–instability paradox]], including in south Asia.<ref>{{cite web|url=http://www.stimson.org/images/uploads/research-pdfs/ESCCONTROLCHAPTER1.pdf|title=The Stability-Instability Paradox, Misperception, and Escalation Control in South Asia|first=Michael|last=Krepon|website=Stimson|access-date=November 20, 2015|url-status=dead|archive-url=https://web.archive.org/web/20150924110533/http://www.stimson.org/images/uploads/research-pdfs/ESCCONTROLCHAPTER1.pdf|archive-date=September 24, 2015}}</ref><ref>{{cite web|url=http://krepon.armscontrolwonk.com/archive/2911/the-stability-instability-paradox|title=Michael Krepon • The Stability-Instability Paradox|access-date=October 24, 2014|url-status=dead|archive-url=https://web.archive.org/web/20150112223352/http://krepon.armscontrolwonk.com/archive/2911/the-stability-instability-paradox|archive-date=January 12, 2015}}</ref> [[Kenneth Waltz]] has argued that nuclear weapons have helped keep an uneasy peace, and further nuclear weapon proliferation might even help avoid the large scale conventional wars that were so common before their invention at the end of [[World War II]].<ref name=waltz/> But former Secretary [[Henry Kissinger]] said in 2010 that there is a new danger, which cannot be addressed by deterrence: "The classical notion of deterrence was that there was some consequences before which aggressors and evildoers would recoil. In a world of suicide bombers, that calculation doesn't operate in any comparable way".<ref>{{cite web |url=https://thehill.com/opinion/columnists/ben-goddard/59952-cold-warriors-say-no-nukes/ |title=Cold Warriors say no nukes |author=Ben Goddard |date=January 27, 2010 |website=The Hill |url-status=live |archive-url=https://web.archive.org/web/20140213100710/http://thehill.com/opinion/columnists/ben-goddard/78391-cold-warriors-say-no-nukes |archive-date=February 13, 2014}}</ref> [[George Shultz]] has said, "If you think of the people who are doing suicide attacks, and people like that get a nuclear weapon, they are almost by definition not deterrable".<ref>{{cite web |url=http://thebulletin.org/new-abolitionists |title=The new abolitionists |author=Hugh Gusterson |date=March 30, 2012 |website=[[Bulletin of the Atomic Scientists]] |url-status=dead |archive-url=https://web.archive.org/web/20140217074609/http://thebulletin.org/new-abolitionists |archive-date=February 17, 2014 |author-link=Hugh Gusterson |access-date=February 2, 2014 }}</ref>

As of early 2019, more than 90% of world's 13,865 nuclear weapons were owned by Russia and the United States.<ref>{{cite news |first=Kelsey |last=Reichmann |title=Here's how many nuclear warheads exist, and which countries own them |url=https://www.defensenews.com/global/2019/06/16/heres-how-many-nuclear-warheads-exist-and-which-countries-own-them/ |work=[[Defense News]] |date=June 16, 2019 |access-date=July 23, 2019 |archive-date=July 28, 2020 |archive-url=https://web.archive.org/web/20200728104810/https://www.defensenews.com/global/2019/06/16/heres-how-many-nuclear-warheads-exist-and-which-countries-own-them/ |url-status=live }}</ref><ref>{{cite news |title=Global Nuclear Arsenal Declines, But Future Cuts Uncertain Amid U.S.-Russia Tensions |url=https://www.rferl.org/a/nuclear-weapons-russia-start-inf-warheads/30003088.html |work=[[Radio Free Europe/Radio Liberty]] (RFE/RL) |date=June 17, 2019 |access-date=July 23, 2019 |archive-date=July 2, 2019 |archive-url=https://web.archive.org/web/20190702194556/https://www.rferl.org/a/nuclear-weapons-russia-start-inf-warheads/30003088.html |url-status=live }}</ref>

=== United Nations ===
{{Main|United Nations Office for Disarmament Affairs}}
The UN Office for Disarmament Affairs (UNODA) is a department of the [[United Nations Secretariat]] established in January 1998 as part of the [[United Nations Secretary-General]] [[Kofi Annan]]'s plan to reform the UN as presented in his report to the [[United Nations General Assembly|General Assembly]] in July 1997.<ref>{{cite web |author=Kofi Annan |url=https://undocs.org/A/51/950 |title=Renewing the United Nations: A Program for Reform |id=A/51/950 |publisher=United Nations |date=July 14, 1997 |access-date=March 17, 2017 |url-status=dead |archive-url=https://web.archive.org/web/20170318000952/http://undocs.org/A/51/950 |archive-date=March 18, 2017}}</ref>

Its goal is to promote nuclear disarmament and [[non-proliferation]] and the strengthening of the disarmament regimes in respect to other weapons of mass destruction, [[chemical weapon|chemical]] and [[biological agent|biological weapons]]. It also promotes disarmament efforts in the area of [[conventional weapon]]s, especially [[land mine]]s and [[small arms]], which are often the weapons of choice in contemporary conflicts.

== Controversy ==
{{See also|Nuclear weapons debate|History of the anti-nuclear movement}}

=== Ethics ===
{{Main|Nuclear ethics}}
[[File:Anti-nuclear weapons protest, UK 1980.JPG|thumb|[[Nuclear disarmament|Anti-nuclear weapons]] protest march in Oxford, 1980]]
Even before the first nuclear weapons had been developed, scientists involved with the [[Manhattan Project]] were divided over the use of the weapon. The role of the two atomic bombings of the country in [[Surrender of Japan|Japan's surrender]] and the US's [[ethics|ethical]] justification for them has been the subject of scholarly and popular debate for decades. The question of whether nations should have nuclear weapons, or test them, has been continually and nearly universally controversial.<ref name="brown">Jerry Brown and [[Rinaldo Brutoco]] (1997). ''Profiles in Power: The Anti-nuclear Movement and the Dawn of the Solar Age'', Twayne Publishers, pp. 191–192.</ref>

=== Notable nuclear weapons accidents ===
{{Main|Nuclear and radiation accidents and incidents|List of military nuclear accidents}}
{{See also|List of nuclear close calls}}

The production and deployment of nuclear weapons has involved many accidents that resulted in either some radiation casualties, or the near-miss possibility of the unauthorized and unintended detonation of a nuclear weapon. These include:

* August 21, 1945: While conducting experiments on a plutonium-gallium core at [[Los Alamos National Laboratory]], physicist [[Harry Daghlian]] received a lethal dose of radiation when an error caused it to enter [[prompt criticality]]. He died 25 days later, on September 15, 1945, from [[Acute radiation syndrome|radiation poisoning]].<ref>{{Cite web |title=Atomic Accidents – Nuclear Museum |url=https://ahf.nuclearmuseum.org/ahf/history/atomic-accidents/ |access-date=2023-11-28 |website=ahf.nuclearmuseum.org/ |language=en-US |archive-date=October 12, 2023 |archive-url=https://web.archive.org/web/20231012072140/https://ahf.nuclearmuseum.org/ahf/history/atomic-accidents/ |url-status=live }}</ref>
* May 21, 1946: While conducting further experiments on the same core at Los Alamos National Laboratory, physicist [[Louis Slotin]] accidentally caused the core to become briefly [[Critical mass|supercritical]]. He received a lethal dose of [[Gamma ray|gamma]] and [[neutron radiation]], and died nine days later on May 30, 1946. After the death of Daghlian and Slotin, the mass became known as the "[[demon core]]". It was ultimately used to construct a bomb for use on the Nevada Test Range.<ref>{{cite web|url=https://www.atlasobscura.com/articles/demon-core-that-killed-two-scientists|title=The Nuclear 'Demon Core' That Killed Two Scientists|date=April 23, 2018|access-date=April 23, 2018|archive-date=April 24, 2018|archive-url=https://web.archive.org/web/20180424024624/https://www.atlasobscura.com/articles/demon-core-that-killed-two-scientists|url-status=live}}</ref>
* February 13, 1950: a [[1950 British Columbia B-36 crash|Convair B-36B crashed]] in northern [[British Columbia]] after jettisoning a [[Mark 4 nuclear bomb|Mark IV]] atomic bomb. This was the first such [[United States military nuclear incident terminology|nuclear weapon loss]] in history. The accident was designated a "[[Broken Arrow (nuclear)|Broken Arrow]]"—an accident involving a nuclear weapon, but which does not present a risk of war. Experts believe that up to 50 nuclear weapons were lost during the Cold War.<ref>{{cite news |title=The Cold War's Missing Atom Bombs |url=https://www.spiegel.de/international/world/a-nuclear-needle-in-a-haystack-the-cold-war-s-missing-atom-bombs-a-590513.html |work=Der Spiegel |date=November 14, 2008 |access-date=August 20, 2019 |archive-url=https://web.archive.org/web/20190627105727/https://www.spiegel.de/international/world/a-nuclear-needle-in-a-haystack-the-cold-war-s-missing-atom-bombs-a-590513.html |archive-date=June 27, 2019 |url-status=live}}</ref>
* May 22, 1957: a {{convert|42,000|lb|adj=on}} [[Mark 17 nuclear bomb|Mark-17 hydrogen bomb]] accidentally fell from a bomber near Albuquerque, New Mexico. The detonation of the device's conventional explosives destroyed it on impact and formed a crater {{convert|25|ft}} in diameter on land owned by the [[University of New Mexico]]. According to a researcher at the Natural Resources Defense Council, it was one of the most powerful bombs made to date.<ref>{{cite news|title=Accident Revealed After 29 Years: H-Bomb Fell Near Albuquerque in 1957 |url=https://www.latimes.com/archives/la-xpm-1986-08-27-mn-14421-story.html|access-date=August 31, 2014|agency=Associated Press|newspaper=Los Angeles Times|date=August 27, 1986 |url-status=live |archive-url=https://web.archive.org/web/20140910195156/http://articles.latimes.com/1986-08-27/news/mn-14421_1_hydrogen-bomb|archive-date=September 10, 2014}}</ref>
* June 7, 1960: the [[1960 Fort Dix IM-99 accident]] destroyed a [[Boeing CIM-10 Bomarc]] nuclear missile and shelter and contaminated the [[BOMARC Missile Accident Site]] in New Jersey.
* January 24, 1961: the [[1961 Goldsboro B-52 crash]] occurred near [[Goldsboro, North Carolina]]. A [[Boeing B-52 Stratofortress]] carrying two [[Mark 39 nuclear bomb]]s broke up in mid-air, dropping its nuclear payload in the process. One of the weapons went through every one of its stages of its firing sequence, save one safety switch.<ref name="BOAS">{{cite magazine |url=https://books.google.com/books?id=dQsAAAAAMBAJ|page=28|magazine=[[Bulletin of the Atomic Scientists]]|date=May 1975|title=Big Bangs from Little Bombs|author=Barry Schneider|access-date=July 13, 2009}}</ref>
* [[1965 Philippine Sea A-4 crash]], where a [[Douglas A-4 Skyhawk|Skyhawk]] attack aircraft with a nuclear weapon fell into the sea.<ref name=CruiseReport>{{cite web|title=Ticonderoga Cruise Reports |url=http://www.history.navy.mil/download/cv-deploy-vietnam.htm |archive-url=https://web.archive.org/web/20040907220034/http://www.history.navy.mil/download/cv-deploy-vietnam.htm |url-status=dead |archive-date=September 7, 2004 |format=Navy.mil weblist of Aug 2003 compilation from cruise reports |access-date=April 20, 2012 |quote=The National Archives hold''[s]'' deck logs for aircraft carriers for the Vietnam Conflict.}}</ref> The pilot, the aircraft, and the [[B43 nuclear bomb]] were never recovered.<ref>[http://www.atomicarchive.com/Almanac/Brokenarrows_static.shtml Broken Arrows] {{webarchive |url=https://web.archive.org/web/20130901064320/http://www.atomicarchive.com/Almanac/Brokenarrows_static.shtml |date=September 1, 2013}} at www.atomicarchive.com. Accessed August 24, 2007.</ref> It was not until 1989 that [[the Pentagon]] revealed the loss of the one-megaton bomb.<ref>{{Cite news |date=May 9, 1989 |title=U.S. Confirms '65 Loss of H-Bomb Near Japanese Islands |newspaper=[[The Washington Post]] |agency=[[Reuters]] |page=A–27}}</ref>
* January 17, 1966: the [[1966 Palomares B-52 crash]] occurred when a [[B-52 Stratofortress|B-52G bomber]] of the [[United States Air Force|USAF]] collided with a [[KC-135 Stratotanker|KC-135 tanker]] during [[Aerial refueling|mid-air refuelling]] off the coast of [[Spain]]. The KC-135 was completely destroyed when its fuel load ignited, killing all four crew members. The B-52G broke apart, killing three of the seven crew members aboard.<ref name="hayes">{{cite news |last=Hayes |first=Ron |date=January 17, 2007 |title=H-bomb incident crippled pilot's career |newspaper=Palm Beach Post |url=http://www.palmbeachpost.com/localnews/content/local_news/epaper/2007/01/17/m1a_Hbomb_0117.html?cxtype=rss&cxsvc=7&cxcat=17 |archive-url=https://web.archive.org/web/20110616223334/http://www.palmbeachpost.com/localnews/content/local_news/epaper/2007/01/17/m1a_Hbomb_0117.html?cxtype=rss&cxsvc=7&cxcat=17 |archive-date=June 16, 2011 |access-date=May 24, 2006 |url-status=dead }}</ref> Of the four [[B28 nuclear bomb|Mk28]] type [[Teller–Ulam design|hydrogen bombs]] the B-52G carried,<ref>{{Cite book |first=Randall C. |last=Maydew |title=America's Lost H-Bomb: Palomares, Spain, 1966 |publisher=Sunflower University Press |isbn=978-0-89745-214-4 |year=1997}}</ref> three were found on land near [[Almería]], Spain. The non-nuclear explosives in two of the weapons detonated upon impact with the ground, resulting in the contamination of a {{convert|2|km2|acre|sp=us|adj=on}} (0.78 square mile) area by [[Radioactive decay|radioactive]] [[plutonium]]. The fourth, which fell into the [[Mediterranean Sea]], was recovered intact after a 2{{frac|1|2}}-month-long search.<ref name=long>{{Cite news |last=Long |first=Tony |date=January 17, 2008 |url=https://www.wired.com/science/discoveries/news/2008/01/dayintech_0117 |title=Jan. 17, 1966: H-Bombs Rain Down on a Spanish Fishing Village |publisher=WIRED |access-date=February 16, 2008 |url-status=live |archive-url=https://web.archive.org/web/20081203112702/http://www.wired.com/science/discoveries/news/2008/01/dayintech_0117 |archive-date=December 3, 2008}}</ref>
* January 21, 1968: the [[1968 Thule Air Base B-52 crash]] involved a [[United States Air Force]] (USAF) [[B-52 Stratofortress|B-52 bomber]]. The aircraft was carrying four [[hydrogen bomb]]s when a cabin fire forced the crew to abandon the aircraft. Six crew members ejected safely, but one who did not have an [[ejection seat]] was killed while trying to bail out. The bomber crashed onto [[sea ice]] in [[Greenland]], causing the nuclear payload to rupture and disperse, which resulted in widespread [[radioactive contamination]].<ref>{{cite news |title=The Cold War's Missing Atom Bombs |url=https://www.spiegel.de/international/world/a-nuclear-needle-in-a-haystack-the-cold-war-s-missing-atom-bombs-a-590513.html |work=Der Spiegel |date=November 14, 2008 |access-date=August 20, 2019 |archive-date=June 27, 2019 |archive-url=https://web.archive.org/web/20190627105727/https://www.spiegel.de/international/world/a-nuclear-needle-in-a-haystack-the-cold-war-s-missing-atom-bombs-a-590513.html |url-status=live }}</ref> One of the bombs remains lost.<ref>{{cite news |title=US left nuclear weapon under ice in Greenland |url=https://www.telegraph.co.uk/news/worldnews/europe/greenland/3439318/US-left-nuclear-weapon-under-ice-in-Greenland.html |archive-url=https://ghostarchive.org/archive/20220110/https://www.telegraph.co.uk/news/worldnews/europe/greenland/3439318/US-left-nuclear-weapon-under-ice-in-Greenland.html |archive-date=January 10, 2022 |url-access=subscription |url-status=live |work=The Daily Telegraph |date=November 11, 2008}}{{cbignore}}</ref>
* September 18–19, 1980: the [[1980 Damascus Titan missile explosion|Damascus Accident]] occurred in Damascus, Arkansas, where a [[Titan Missile Museum|Titan Missile]] equipped with a nuclear warhead exploded. The accident was caused by a maintenance man who dropped a socket from a socket wrench down an {{convert|80|ft|adj=on}} shaft, puncturing a fuel tank on the rocket. Leaking fuel resulted in a [[hypergolic]] fuel explosion, jettisoning the [[W-53 warhead]] beyond the launch site.<ref>{{Cite book |last=Schlosser |first=Eric |title=Physics Today |date=2013 |isbn=978-1-59420-227-8 |volume=67 |pages=[https://archive.org/details/commandcontrol00eric/page/48 48–50] |chapter=Command and Control: Nuclear Weapons, the Damascus Accident, and the Illusion of Safety |bibcode=2014PhT....67d..48W |doi=10.1063/PT.3.2350 |chapter-url=https://archive.org/details/commandcontrol00eric/page/48 |issue=4}}</ref><ref>{{cite web |last=Christ |first=Mark K. |title=Titan II Missile Explosion |url=http://www.encyclopediaofarkansas.net/encyclopedia/entry-detail.aspx?entryID=2543 |url-status=live |archive-url=https://web.archive.org/web/20140912135526/http://www.encyclopediaofarkansas.net/encyclopedia/entry-detail.aspx?entryID=2543 |archive-date=September 12, 2014 |access-date=August 31, 2014 |website=The Encyclopedia of Arkansas History & Culture |publisher=Arkansas Historic Preservation Program}}</ref><ref>{{cite book |last=Stumpf |first=David K. |title="We Can Neither Confirm Nor Deny" Sentinels of History: Refelections on Arkansas Properties on the National Register of Historic Places |date=2000 |publisher=[[University of Arkansas Press]] |editor1-last=Christ |editor1-first=Mark K. |location=Fayetteville, Arkansas |editor2-last=Slater |editor2-first=Cathryn H.}}</ref>

Governmental nuclear agencies frequently point to their procedures and technical safeguards as what has prevented accidental nuclear explosions. But it has also been argued by historians, political scientists, and historical participants that in many instances, the avoidance of an unintended nuclear explosions was due less to correct implementation of controls, but instead can be attributed to disobedience, technical failures, or other factors beyond strict human control.{{citation needed|date=October 2025}} Reliance on non-controlled factors is sometimes referred to as "luck".<ref>"'Lucky' nuclear close calls can be defined as instances in which unwanted nuclear explosions were avoided either 'independently' of control practices, 'despite' control practices, or ‘because of the failure of’ control practices."{{cite journal|first1=Benoît|last1=Pelopidas|first2=Kjolv|last2=Egeland|title=The False Promise of Nuclear Risk Reduction|journal=International Affairs|volume=100|number=1|date=January 2024|pp=345–360|doi=10.1093/ia/iiad290|url=https://sciencespo.hal.science/hal-03458635v1/document}}. Other sources on the role of luck include {{cite book|first=Scott|last=Sagan|title=The limits of safety: organizations, accidents, and nuclear weapons|publisher=Princeton University Press|year=1993|pp= 154–155}},{{cite book|first=Eric|last=Schlosser|title=Command and Control: Nuclear Weapons, the Damascus Accident, and the Illusion of Safety|publisher=Allen Lane|year=2013}}, and {{cite journal|first=Benoît|last=Pelopidas|title=The unbearable lightness of luck: Three sources of overconfidence in the manageability of nuclear crises|journal=European Journal of International Security|volume=2|number=2|year=2017|pp=240–262}}</ref> General [[George Lee Butler]], commander of the US [[Strategic Air Command]] (1991–1992), argued in 1999 that "...we escaped the Cold War without a nuclear holocaust by some combination of skill, luck, and divine intervention, and I suspect the latter in greatest proportion."<ref>{{cite web|first=George Lee|last=Butler|url=https://www.wagingpeace.org/general-lee-butler-addresses-the-canadian-network-against-nuclear-weapons/|title=General Lee Butler Addresses The Canadian Network Against Nuclear Weapons|date=March 11, 1999|website=Waging Peace}}</ref> Dean Acheson, US [[Secretary of State]] during the [[Cuban Missile Crisis]], concluded similarly in 1969 that it was ultimately "plain dumb luck" that resolved that crisis peacefully.<ref>{{cite journal|url=https://classic.esquire.com/article/1969/2/1/dean-achesons-version-of-robert-kennedys-version-of-the-cuban-missile-affair|date=February 1, 1969|journal=Esquire|title=Dean Acheson's version of Robert Kennedy's version of the Cuban Missile Affair}}</ref>

=== Nuclear testing and fallout ===
{{Main|Nuclear fallout}} {{See also|Downwinders}}
[[File:Rael Nuclear use locations world map.png|thumb|upright=2.25|Over 2,000 nuclear explosions have been conducted in over a dozen different sites around the world. Red Russia/Soviet Union, blue France, light blue United States, violet Britain, yellow China, orange India, brown Pakistan, green North Korea and light green (territories exposed to nuclear bombs). The black dot indicates the location of the [[Vela incident]].]]
[[File:Atomic test seen from Las Vegas.jpg|thumb|right|This view of downtown [[Las Vegas]] shows a [[mushroom cloud]] in the background. Scenes such as this were typical during the 1950s. From 1951 to 1962 the government conducted 100 atmospheric tests at the nearby [[Nevada Test Site]].]]

Over 500 atmospheric nuclear weapons tests were conducted at various sites around the world from 1945 to 1980. [[Radioactive fallout]] from nuclear weapons testing was first drawn to public attention in 1954 when the [[Castle Bravo]] hydrogen bomb test at the [[Pacific Proving Grounds]] contaminated the crew and catch of the Japanese fishing boat ''[[Daigo Fukuryū Maru|Lucky Dragon]]''.<ref name=rudig2/> One of the fishermen died in Japan seven months later, and the fear of contaminated [[tuna]] led to a temporary boycotting of the popular staple in Japan. The incident caused widespread concern around the world, especially regarding the effects of nuclear fallout and atmospheric [[nuclear testing]], and "provided a decisive impetus for the emergence of the anti-nuclear weapons movement in many countries".<ref name=rudig2>{{cite book |last=Rudig |first=Wolfgang |date=1990 |title=Anti-nuclear Movements: A World Survey of Opposition to Nuclear Energy |url=https://books.google.com/books?id=ZXwfAQAAIAAJ |publisher=Longman |pages=54–55 |isbn=978-0582902695}}</ref>

As public awareness and concern mounted over the possible health hazards associated with exposure to the nuclear fallout, various studies were done to assess the extent of the hazard. A [[Centers for Disease Control and Prevention]]/ [[National Cancer Institute]] study claims that fallout from atmospheric nuclear tests would lead to perhaps 11,000 excess deaths among people alive during atmospheric testing in the United States from all forms of cancer, including leukemia, from 1951 to well into the 21st century.<ref>{{cite web|title=Report on the Health Consequences to the American Population from Nuclear Weapons Tests Conducted by the United States and Other Nations |url=https://www.cdc.gov/nceh/radiation/fallout/|publisher=CDC|access-date=December 7, 2013 |url-status=live |archive-url=https://web.archive.org/web/20131204164348/http://www.cdc.gov/nceh/radiation/fallout/|archive-date=December 4, 2013}}</ref><ref>{{cite book |url=https://nap.nationalacademies.org/catalog/10621/exposure-of-the-american-population-to-radioactive-fallout-from-nuclear-weapons-tests |title=Exposure of the American Population to Radioactive Fallout from Nuclear Weapons Tests |archive-url=https://web.archive.org/web/20140907210530/http://books.nap.edu/catalog.php?record_id=10621|archive-date=September 7, 2014 |doi=10.17226/10621 |pmid=25057651 |year=2003 |isbn=978-0-309-08713-1 |url-status=live}}</ref>
{{as of|2009|March}}, the US is the only nation that compensates nuclear test victims. Since the [[Radiation Exposure Compensation Act]] of 1990, more than $1.38&nbsp;billion in compensation has been approved. The money is going to people who took part in the tests, notably at the [[Nevada Test Site]], and to others exposed to the radiation.<ref name=compo>{{cite web|url=https://abcnews.go.com/International/wireStory?id=7159303|title=What governments offer to victims of nuclear tests|website=ABC News|access-date=October 24, 2014|archive-date=January 18, 2023|archive-url=https://web.archive.org/web/20230118174820/https://abcnews.go.com/International/wireStory?id=7159303|url-status=live}}</ref><ref>{{cite web |url=http://www.usdoj.gov/civil/omp/omi/Tre_SysClaimsToDateSum.pdf|title=Radiation Exposure Compensation System: Claims to Date Summary of Claims Received by 06/11/2009 |url-status=live |archive-url=https://web.archive.org/web/20090907192321/http://www.usdoj.gov/civil/omp/omi/Tre_SysClaimsToDateSum.pdf|archive-date=September 7, 2009}}</ref>

In addition, leakage of byproducts of nuclear weapon production into groundwater has been an ongoing issue, particularly at the [[Hanford site]].<ref name="Hanford Ref">{{cite web|last=Coghlan|first=Andy|title=US nuclear dump is leaking toxic waste |url=https://www.newscientist.com/article/dn23214-us-nuclear-dump-is-leaking-toxic-waste/|website=New Scientist|access-date=March 12, 2016 |url-status=live |archive-url=https://web.archive.org/web/20160413045211/https://www.newscientist.com/article/dn23214-us-nuclear-dump-is-leaking-toxic-waste/|archive-date=April 13, 2016}}</ref>

== Effects of nuclear explosions ==
{{Main|Effects of nuclear explosions}}

=== Effects of nuclear explosions on human health ===
{{Main|Effects of nuclear explosions on human health}}
[[File:Sumiteru Taniguchi back.jpg|thumb|A photograph of [[Sumiteru Taniguchi]]'s back injuries taken in January 1946 by a US Marine photographer]]
Some scientists estimate that a nuclear war with 100 Hiroshima-size nuclear explosions on cities could cost the lives of tens of millions of people from long-term climatic effects alone. The climatology hypothesis is that ''if'' each city [[firestorm]]s, a great deal of soot could be thrown up into the atmosphere which could blanket the earth, cutting out sunlight for years on end, causing the disruption of food chains, in what is termed a [[nuclear winter]].<ref>Philip Yam. Nuclear Exchange, ''Scientific American'', June 2010, p. 24.</ref><ref>Alan Robock and Owen Brian Toon. Local Nuclear War, Global Suffering, ''Scientific American'', January 2010, pp. 74–81.</ref>

People near the Hiroshima explosion and who managed to survive the explosion subsequently suffered a variety of horrible medical effects. Some of these effects are still present to this day:<ref>{{Cite web |url=https://k1project.columbia.edu/news/hiroshima-and-nagasaki|title=Hiroshima and Nagasaki: The Long Term Health Effects {{!}} K=1 Project|website=k1project.columbia.edu|language=en|access-date=September 7, 2017 |url-status=live |archive-url=https://web.archive.org/web/20170620041039/https://k1project.columbia.edu/news/hiroshima-and-nagasaki |archive-date=June 20, 2017}}</ref>
* Initial stage – the first 1–9 weeks, in which are the greatest number of deaths, with 90% due to thermal injury or blast effects and 10% due to super-lethal [[radiation]] exposure.
* Intermediate stage – from 10 to 12 weeks. The deaths in this period are from [[ionizing radiation]] in the median lethal range – {{LD50}}
* Late period – lasting from 13 to 20 weeks. This period has some improvement in survivors' condition.
* Delayed period – from 20-plus weeks. Characterized by numerous complications, mostly related to healing of thermal and mechanical injuries, and if the individual was exposed to a few hundred to a thousand [[millisievert]]s of radiation, it is coupled with infertility, sub-fertility and blood disorders. Furthermore, ionizing radiation above a dose of around 50–100-millisievert exposure has been shown to statistically begin increasing one's chance of dying of cancer sometime in their lifetime over the normal unexposed rate of ~25%, in the long term, a heightened rate of cancer, proportional to the dose received, would begin to be observed after ~5-plus years, with lesser problems such as eye [[cataract]]s and other more minor effects in other organs and tissue also being observed over the long term.

Fallout exposure—depending on if further afield individuals [[shelter in place]] or evacuate perpendicular to the direction of the wind, and therefore avoid contact with the fallout plume, and stay there for the days and weeks after the nuclear explosion, their exposure to fallout, and therefore their total dose, will vary. With those who do shelter in place, and or evacuate, experiencing a total dose that would be negligible in comparison to someone who just went about their life as normal.<ref>{{cite web |url-status=live |quote=7 hour rule: At 7 hours after detonation the fission product activity will have decreased to about 1/10 (10%) of its amount at 1 hour. At about 2 days (49 hours-7X7) the activity will have decreased to 1% of the 1-hour value |url=http://www.falloutradiation.com/johnwayne7 |website=Fallout Radiation.com |title=Decay Information |archive-url=https://web.archive.org/web/20110831072351/http://www.falloutradiation.com/johnwayne7 |archive-date=August 31, 2011}}</ref><ref>{{cite web|url=http://www3.nd.edu/~nsl/Lectures/phys205/pdf/Nuclear_Warfare_9.pdf|title=Nuclear Warfare|page=22|url-status=dead|archive-url=https://web.archive.org/web/20131126220402/http://www3.nd.edu/~nsl/Lectures/phys205/pdf/Nuclear_Warfare_9.pdf|archive-date=November 26, 2013|access-date=May 21, 2016}}</ref>

Staying indoors until after the most hazardous fallout [[isotope]], [[I-131]] decays away to 0.1% of its initial quantity after ten [[half-life]]s—which is represented by 80 days in [[I-131]]s case, would make the difference between likely contracting [[Thyroid cancer]] or escaping completely from this substance depending on the actions of the individual.<ref>{{cite web|title=Public Health Assessment – Iodine-131 Releases |url=http://www.atsdr.cdc.gov/HAC/PHA/OakRidgeI131_022508/I%20131%20Final_02_25_08_508.pdf |date=March 2008 |website=Agency for Toxic Substances and Disease Registry |publisher=U.S. Center for Disease Control|access-date=May 21, 2016 |url-status=live |archive-url=https://web.archive.org/web/20160511014537/http://www.atsdr.cdc.gov/HAC/pha/oakridgeI131_022508/I%20131%20Final_02_25_08_508.pdf |archive-date=May 11, 2016}}</ref>

=== Effects of nuclear war ===
{{See also|Nuclear holocaust|Doomsday Clock|Doomsday device|World War III|Nuclear famine}}
[[File:Castle Bravo 007.jpg|thumb|Mushroom cloud from the explosion of [[Castle Bravo]], the largest nuclear weapon detonated by the US, in 1954]]
Nuclear war could yield unprecedented human death tolls and [[habitat destruction]]. Detonating large numbers of nuclear weapons would have an immediate, short term and long-term effects on the climate, potentially causing cold weather known as a "[[nuclear winter]]".<ref>{{Cite news |last=Meyer |first=Robinson |date=April 29, 2016 |title=You're More Likely to Die in a Human Extinction Event Than a Car Crash |work=The Atlantic |url=https://www.theatlantic.com/technology/archive/2016/04/a-human-extinction-isnt-that-unlikely/480444/ |access-date=April 19, 2020 |archive-date=May 1, 2016 |archive-url=https://web.archive.org/web/20160501051000/http://www.theatlantic.com/technology/archive/2016/04/a-human-extinction-isnt-that-unlikely/480444/ |url-status=live }}</ref><ref name="newstudy-2022">{{cite news |last=Diaz-Maurin |first=François |title=Nowhere to hide: How a nuclear war would kill you — and almost everyone else |url=https://thebulletin.org/2022/10/nowhere-to-hide-how-a-nuclear-war-would-kill-you-and-almost-everyone-else/ |work=[[Bulletin of the Atomic Scientists]] |date=20 October 2022 |access-date=October 26, 2022 |archive-date=October 26, 2022 |archive-url=https://web.archive.org/web/20221026154805/https://thebulletin.org/2022/10/nowhere-to-hide-how-a-nuclear-war-would-kill-you-and-almost-everyone-else/ |url-status=live }}</ref> In 1982, [[Brian Martin (social scientist)|Brian Martin]] estimated that a [[Nuclear arms race|US–Soviet nuclear exchange]] might kill 400–450&nbsp;million directly, mostly in the United States, Europe and Russia, and maybe several hundred million more through follow-up consequences in those same areas.<ref>{{Cite journal |last=Martin |first=Brian |date=1982 |title=Critique of nuclear extinction |url=https://www.bmartin.cc/pubs/82jpr.html |journal=Journal of Peace Research |volume=19 |issue=4 |pages=287–300 |doi=10.1177/002234338201900401 |access-date=October 25, 2014 |s2cid=110974484 |archive-date=April 4, 2020 |archive-url=https://web.archive.org/web/20200404000718/https://www.bmartin.cc/pubs/82jpr.html |url-status=live }}</ref> Many scholars have posited that a global thermonuclear war with Cold War-era stockpiles, or even with the current smaller stockpiles, may lead to the [[Human extinction|extinction of the human race]].<ref>{{cite journal |author=Tonn, Bruce |author2=MacGregor, Donald |name-list-style=amp |doi=10.1016/j.futures.2009.07.009 |title=A singular chain of events |journal=Futures |volume=41 |issue=10 |year=2009 |pages=706–714|s2cid=144553194 }}</ref> The ''International Physicians for the Prevention of Nuclear War'' believe that nuclear war could indirectly contribute to human extinction via secondary effects, including environmental consequences, [[societal collapse|societal breakdown]], and economic collapse. It has been estimated that a relatively small-scale nuclear exchange between [[India–Pakistan relations|India and Pakistan]] involving 100 [[Atomic bombings of Hiroshima and Nagasaki|Hiroshima]] yield (15 kilotons) weapons, could cause a nuclear winter and kill more than a billion people.<ref>{{cite web |last=Helfand |first=Ira |title=Nuclear Famine: Two Billion People at Risk? |url=http://www.ippnw.org/pdf/nuclear-famine-two-billion-at-risk-2013.pdf |website=[[International Physicians for the Prevention of Nuclear War]] |access-date=13 February 2016 |archive-date=April 5, 2016 |archive-url=https://web.archive.org/web/20160405015355/http://www.ippnw.org/pdf/nuclear-famine-two-billion-at-risk-2013.pdf |url-status=live }}</ref>

According to a peer-reviewed study published in the journal ''[[Nature Food]]'' in August 2022, a full-scale nuclear war between the US and Russia would directly kill 360 million people and more than 5 billion people would die from [[starvation]]. More than 2 billion people could die from a smaller-scale nuclear war between India and Pakistan.<ref name="newstudy-2022"/><ref>{{cite news |title=World Nuclear war between the U.S. and Russia would kill more than 5 billion people – just from starvation, study finds |url=https://www.cbsnews.com/news/nuclear-war-5-billion-people-starvation-deaths-study/ |work=CBS News |date=16 August 2022 |access-date=October 26, 2022 |archive-date=October 26, 2022 |archive-url=https://web.archive.org/web/20221026190805/https://www.cbsnews.com/news/nuclear-war-5-billion-people-starvation-deaths-study/ |url-status=live }}</ref><ref>{{cite journal |title=Global food insecurity and famine from reduced crop, marine fishery and livestock production due to climate disruption from nuclear war soot injection |journal=[[Nature Food]] |date=15 August 2022 |doi=10.1038/s43016-022-00573-0 |last1=Xia |first1=Lili |last2=Robock |first2=Alan |last3=Scherrer |first3=Kim |last4=Harrison |first4=Cheryl S. |last5=Bodirsky |first5=Benjamin Leon |last6=Weindl |first6=Isabelle |last7=Jägermeyr |first7=Jonas |last8=Bardeen |first8=Charles G. |last9=Toon |first9=Owen B. |last10=Heneghan |first10=Ryan |volume=3 |issue=8 |pages=586–596 |pmid=37118594 |s2cid=251601831 |doi-access=free |bibcode=2022NatFd...3..586X |hdl=11250/3039288 |hdl-access=free }}</ref>

=== Public opposition ===
{{See also|Nuclear disarmament|International Day against Nuclear Tests}}
[[File:Massale vredesdemonstratie in Bonn tegen de modernisering van kernwapens in West, Bestanddeelnr 253-8611.jpg|thumb|Protest in Bonn against the [[nuclear arms race]] between the US/NATO and the Warsaw Pact, 1981]]
[[File:Essais nucleaires manif.jpg|thumb|right|Demonstration against nuclear testing in [[Lyon]], France, in the 1980s]]

Peace movements emerged in Japan and in 1954 they converged to form a unified "[[Japan Council against Atomic and Hydrogen Bombs]]." Japanese opposition to nuclear weapons tests in the Pacific Ocean was widespread, and "an estimated 35 million signatures were collected on petitions calling for bans on nuclear weapons".<ref name=falkj>Jim Falk (1982). ''Global Fission: The Battle Over Nuclear Power'', Oxford University Press, pp. 96–97.</ref>

In the United Kingdom, the [[Aldermaston Marches]] organised by the [[Campaign for Nuclear Disarmament]] (CND) took place at [[Easter]] 1958, when, according to the CND, several thousand people marched for four days from [[Trafalgar Square]], London, to the [[Atomic Weapons Establishment|Atomic Weapons Research Establishment]] close to [[Aldermaston]] in [[Berkshire]], England, to demonstrate their opposition to nuclear weapons.<ref name=CND>{{cite web |url=http://www.cnduk.org/pages/binfo/hist.html |title=A brief history of CND |publisher=Cnduk.org |access-date=May 30, 2013 |url-status=live |archive-url=https://web.archive.org/web/20040617103503/http://www.cnduk.org/pages/binfo/hist.html |archive-date=June 17, 2004}}</ref><ref name=GuardianUnlimited:1958>{{cite news |work=[[Guardian Unlimited]] |title=Early defections in march to Aldermaston |date=April 5, 1958 |url=https://www.theguardian.com/century/1950-1959/Story/0,,105488,00.html |location=London |url-status=live |archive-url=https://web.archive.org/web/20061008112515/http://century.guardian.co.uk/1950-1959/Story/0,,105488,00.html |archive-date=October 8, 2006}}</ref> The Aldermaston marches continued into the late 1960s when tens of thousands of people took part in the four-day marches.<ref name=falkj/>

In 1959, a letter in the ''Bulletin of the Atomic Scientists'' was the start of a successful campaign to stop the [[United States Atomic Energy Commission|Atomic Energy Commission]] dumping [[radioactive waste]] in the sea 19 kilometers from [[Boston]].<ref>Jim Falk (1982). ''Global Fission: The Battle Over Nuclear Power'', Oxford University Press, p. 93.</ref> In 1962, [[Linus Pauling]] won the [[Nobel Peace Prize]] for his work to stop the atmospheric testing of nuclear weapons, and the "Ban the Bomb" movement spread.<ref name="brown"/>

In 1963, many countries ratified the [[Partial Test Ban Treaty]] prohibiting atmospheric nuclear testing. Radioactive fallout became less of an issue and the anti-nuclear weapons movement went into decline for some years.<ref name=rudig2/><ref>Jim Falk (1982). ''Global Fission: The Battle Over Nuclear Power'', Oxford University Press, p. 98.</ref> A resurgence of interest occurred amid European and American [[Radiophobia|fears of nuclear war]] in the 1980s.<ref>Spencer Weart, ''Nuclear Fear: A History of Images'' (Cambridge, Massachusetts: Harvard University Press, 1988), chapters 16 and 19.</ref>

== Costs and technology spin-offs ==
{{See also|Global Positioning System|Nuclear weapons delivery|History of computing hardware|ENIAC|Swords to ploughshares}}
According to an audit by the [[Brookings Institution]], between 1940 and 1996, the US spent ${{Format price|{{Inflation|US|5821000000000|1996|r=3}}}} in present-day terms{{Inflation-fn|US}} on nuclear weapons programs, 57% of which was spent on building [[nuclear weapons delivery]] systems. Six-point-three percent  of the total amount, ${{Format price|{{Inflation|US|365000000000|1996|r=3}}}} in present-day terms, was spent on [[environmental remediation]] and [[nuclear waste management]]—for example, cleaning up the [[Hanford site]]—and 7% of the total $820 billion was spent on making nuclear weapons themselves.<ref>{{cite web |url=http://www.brookings.edu/fp/projects/nucwcost/figure1.htm|website=Brookings Institution|title=Estimated Minimum Incurred Costs of U.S. Nuclear Weapons Programs, 1940–1996 |access-date=November 20, 2015 |archive-url=https://web.archive.org/web/20040305101238/http://www.brookings.edu/fp/projects/nucwcost/figure1.htm |archive-date=March 5, 2004}}</ref>

== Non-weapons uses ==
{{Main|Peaceful nuclear explosion}}
Peaceful nuclear explosions (PNEs) are [[nuclear explosion]]s conducted for non-military purposes, such as activities related to [[economic development]] including the creation of [[canal]]s. During the 1960s and 1970s, both the United States and the Soviet Union conducted a number of PNEs.<ref>{{Cite web |url=https://scienceandglobalsecurity.org/archive/sgs07nordyke.pdf |title=Archived copy |access-date=May 14, 2024 |archive-date=May 14, 2024 |archive-url=https://web.archive.org/web/20240514144116/https://scienceandglobalsecurity.org/archive/sgs07nordyke.pdf |url-status=live }}</ref> The United States created plans for several uses of PNEs, including [[Project Plowshare|Operation Plowshare]].<ref>{{Cite web |url=https://www.osti.gov/opennet/reports/plowshar.pdf |title=Archived copy |access-date=May 14, 2024 |archive-date=April 3, 2024 |archive-url=https://web.archive.org/web/20240403165317/https://www.osti.gov/opennet/reports/plowshar.pdf |url-status=live }}</ref> Six of the explosions by the Soviet Union are considered to have been of an applied nature, not just tests.

The United States and the Soviet Union later halted their programs. Definitions and limits are covered in the Peaceful Nuclear Explosions Treaty of 1976.<ref>{{cite web |url=http://www.fordlibrarymuseum.gov/library/document/0248/whpr19760527-013.pdf |date=May 28, 1976 |title=Announcement of Treaty on Underground Nuclear Explosions Peaceful Purposes (PNE Treaty) |publisher=Gerald R. Ford Museum and Library |url-status=dead |archive-url=https://web.archive.org/web/20160305223640/https://www.fordlibrarymuseum.gov/library/document/0248/whpr19760527-013.pdf |archive-date=March 5, 2016 |access-date=February 22, 2016}}</ref><ref>{{cite web |url=http://www.presidency.ucsb.edu/ws/?pid=6245 |title=Gerald R. Ford: "Message to the Senate Transmitting United States-Soviet Treaty and Protocol on the Limitation of Underground Nuclear Explosions", July 29, 1976 |last1=Peters |first1=Gerhard |last2=Woolley |first2=John T |publisher=University of California – Santa Barbara |website=The American Presidency Project |url-status=dead |archive-url=https://web.archive.org/web/20160303170850/http://www.presidency.ucsb.edu/ws/?pid=6245 |archive-date=March 3, 2016 |access-date=February 22, 2016 }}</ref> The stalled [[Comprehensive Nuclear-Test-Ban Treaty]] of 1996 would prohibit all nuclear explosions, regardless of whether they are for peaceful purposes or not.<ref>{{cite web|title=Status of Signature and Ratification |url=https://www.ctbto.org/the-treaty/status-of-signature-and-ratification/|website=ctbto dot org|publisher=CTBT Organization Preparatory Commission |access-date=December 29, 2016 |url-status=dead |archive-url=https://web.archive.org/web/20161228205543/http://ctbto.org/the-treaty/status-of-signature-and-ratification |archive-date=December 28, 2016}}</ref>

== History of development ==
{{Main|History of nuclear weapons}}
{{See also|Soviet atomic bomb project|Manhattan Project|Cold War|History of the Teller–Ulam design}}
{{Excerpt|History of nuclear weapons|Background|paragraphs=1, 3-6, 9-13}}

== See also ==
{{div col}}
* [[Cobalt bomb]]
* [[Cosmic bomb (phrase)]]
* [[Cuban Missile Crisis]]
* [[Dirty bomb]]
* [[International Day for the Total Elimination of Nuclear Weapons]]
* [[List of global issues]]
* [[List of nuclear weapons]]
* [[List of states with nuclear weapons]]
* [[Nth Country Experiment]]
* [[Nuclear blackout]]
* [[Nuclear bunker buster]]
* [[Nuclear weapons of the United Kingdom]]
* [[Nuclear weapons in popular culture]]
* [[Nuclear weapons of the United States]]
* [[OPANAL]] (Agency for the Prohibition of Nuclear Weapons in Latin America and the Caribbean)
* [[Three Non-Nuclear Principles]] of Japan
{{div col end}}
{{Portal bar|Nuclear technology}}

==Notes==
{{Notelist}}

==References==
{{Reflist}}

===Bibliography===
{{refbegin}}
* [[Hans Bethe|Bethe, Hans Albrecht]]. ''The Road from Los Alamos''. New York: Simon and Schuster, 1991. {{ISBN|0-671-74012-1}}.
* DeVolpi, Alexander, Minkov, Vladimir E., Simonenko, Vadim A., and Stanford, George S. ''Nuclear Shadowboxing: Contemporary Threats from Cold War Weaponry''. Fidlar Doubleday, 2004 (Two volumes, both accessible on Google Book Search. Content of both volumes is now available in the 2009 trilogy by Alexander DeVolpi: ''Nuclear Insights: The Cold War Legacy''.).
* Glasstone, Samuel and Dolan, Philip J. ''[https://web.archive.org/web/20050204002118/http://www.cddc.vt.edu/host/atomic/nukeffct/ The Effects of Nuclear Weapons (third edition)]''. Washington, D.C.: U.S. Government Printing Office, 1977. [https://web.archive.org/web/20090227073933/http://www.princeton.edu/~globsec/publications/effects/effects.shtml Available online (PDF)].
* ''[https://fas.org/nuke/guide/usa/doctrine/dod/fm8-9/1toc.htm NATO Handbook on the Medical Aspects of NBC Defensive Operations (Part I – Nuclear)]''. ({{Webarchive|url=https://web.archive.org/web/20150408021307/http://fas.org/nuke/guide/usa/doctrine/dod/fm8-9/1toc.htm |date=April 8, 2015 }}). Departments of the Army, Navy, and Air Force: Washington, D.C., 1996
* [[Chuck Hansen|Hansen, Chuck]]. ''U.S. Nuclear Weapons: The Secret History''. Arlington, TX: Aerofax, 1988.
* Hansen, Chuck, "[http://www.uscoldwar.com/ Swords of Armageddon: U.S. nuclear weapons development since 1945]" (CD-ROM & download available; 2nd Ed.). ({{Webarchive|url=https://web.archive.org/web/20161230020259/http://www.uscoldwar.com/ |date=December 30, 2016 }}). PDF. 2,600 pages, Sunnyvale, California, Chucklea Publications, 1995, 2007. {{ISBN|978-0-9791915-0-3}}.
* Holloway, David. ''Stalin and the Bomb''. New Haven: Yale University Press, 1994. {{ISBN|0-300-06056-4}}.
* {{cite book |last=Jungk |first=Robert |author-link=Robert Jungk |year=1958 |title=[[Brighter than a Thousand Suns: A Personal History of the Atomic Scientists]] |location=New York |publisher=[[Harcourt (publisher)|Harcourt]] |isbn=0-15-614150-7 |oclc=181321}}
* The Manhattan Engineer District, "[http://www.atomicarchive.com/Docs/MED/index.shtml The Atomic Bombings of Hiroshima and Nagasaki]" (1946), {{Webarchive|url=https://web.archive.org/web/20120204055504/http://www.atomicarchive.com/Docs/MED/index.shtml |date=February 4, 2012 }}
* {{in lang|fr}} Jean-Hugues Oppel, ''Réveillez le président'', Éditions Payot et rivages, 2007 ({{ISBN|978-2-7436-1630-4}}). The book is a fiction about the [[Force de Frappe|nuclear weapons]] of France; the book also contains about ten chapters on true historical incidents involving nuclear weapons and strategy.
* ''[https://web.archive.org/web/20150418011842/http://fas.org/nuke/intro/nuke/7906/index.html The Effects of Nuclear War]''. Office of Technology Assessment, May 1979.
* [[Richard Rhodes|Rhodes, Richard]]. ''Dark Sun: The Making of the Hydrogen Bomb''. New York: Simon and Schuster, 1995. {{ISBN|0-684-82414-0}}.
* {{cite book |last=Rhodes |first=Richard |author-link=Richard Rhodes |title=[[The Making of the Atomic Bomb]] |location=New York |publisher=Simon & Schuster |year=1986 |isbn=0-671-44133-7 |oclc=13793436}}
* [[George Shultz|Shultz, George P.]] and Goodby, James E. ''The War that Must Never Be Fought'', Hoover Press, 2015, {{ISBN|978-0-8179-1845-3}}.
* [[Henry DeWolf Smyth|Smyth, Henry DeWolf]]. ''[http://www.atomicarchive.com/Docs/SmythReport/index.shtml Atomic Energy for Military Purposes]''. ({{Webarchive|url=https://web.archive.org/web/20170421015824/http://www.atomicarchive.com/Docs/SmythReport/index.shtml |date=April 21, 2017 }}). Princeton, NJ: Princeton University Press, 1945. [[Smyth Report]]{{spaced ndash}}the first declassified report by the US government on nuclear weapons.
* [[Spencer Weart|Weart, Spencer R.]] ''Nuclear Fear: A History of Images''. Cambridge, Massachusetts: Harvard University Press, 1988. {{ISBN|0-674-62836-5}}.
* Weart, Spencer R. ''The Rise of Nuclear Fear''. Cambridge, Massachusetts: Harvard University Press, 2012. {{ISBN|0-674-05233-1}}.
{{refend}}

== Further reading ==
{{See also|List of books about nuclear issues}}
{{Library resources box}}
{{refbegin|30em}}
* [[Laura Grego]] and David Wright, "Broken Shield: Missiles designed to destroy incoming nuclear warheads fail frequently in tests and could increase global risk of mass destruction", ''[[Scientific American]]'', vol. 320, no. no. 6 (June 2019), pp.&nbsp;62–67. "Current U.S. [[missile defense]] plans are being driven largely by [[technology]], [[politics]] and [[fear]]. Missile defenses will not allow us to escape our vulnerability to nuclear weapons. Instead large-scale developments will create barriers to taking real steps toward [[Nuclear disarmament|reducing nuclear risks]]—by blocking further cuts in nuclear arsenals and potentially spurring new deployments." (p.&nbsp;67.)
* [[Michael T. Klare]], "Missile Mania: The death of the [[INF Treaty|INF [Intermediate-Range Nuclear Forces] Treaty]] [of 1987] has escalated the arms race", ''[[The Nation]]'', vol. 309, no. 6 (September 23, 2019), p.&nbsp;4.
* [[Ernest J. Moniz|Moniz, Ernest J.]], and [[Sam Nunn]], "The Return of Doomsday: The New Nuclear Arms Race – and How Washington and Moscow Can Stop It", ''[[Foreign Affairs]]'', vol. 98, no. 5 (September / October 2019), pp.&nbsp;150–161. Former [[U.S. Secretary of Energy]] [[Ernest Moniz]] and former [[U.S. Senator]] [[Sam Nunn]] write that "the old [strategic] equilibrium" between the United States and Russia has been "destabilized" by "clashing national interests, insufficient dialogue, eroding arms control structures, advanced missile systems, and new [[cyberweapon]]s... Unless Washington and Moscow confront these problems now, a major international conflict or nuclear escalation is disturbingly plausible—perhaps even likely." (p.&nbsp;161.)
* [[Thomas Powers]], "The Nuclear Worrier" (review of [[Daniel Ellsberg]], ''The Doomsday Machine: Confessions of a [[Nuclear War]] Planner'', New York, Bloomsbury, 2017, {{ISBN|9781608196708}}, 420 pp.), ''[[The New York Review of Books]]'', vol. LXV, no. 1 (January 18, 2018), pp.&nbsp;13–15.
* [[Eric Schlosser]], ''[[Command and Control: Nuclear Weapons, the Damascus Accident, and the Illusion of Safety]]'', [[Penguin Press]], 2013, {{ISBN|1594202273}}. The book became the basis for a 2-hour 2017 [[PBS]] [[American Experience]] episode, likewise titled "Command and Control". Nuclear weapons continue to be equally hazardous to their owners as to their potential targets. Under the 1970 [[Treaty on the Non-Proliferation of Nuclear Weapons]], [[nuclear-weapon states]] are obliged to work toward the elimination of nuclear weapons.
* Tom Stevenson, "A Tiny Sun" (review of [[Fred Kaplan (journalist)|Fred Kaplan]], ''The Bomb: Presidents, Generals, and the Secret History of Nuclear War'', Simon and Schuster, 2021, 384 pp.; and Keir A. Lieber and Daryl G. Press, ''The Myth of the Nuclear Revolution: Power Politics in the Atomic Age'', Cornell, 2020, 180 pp.), ''[[London Review of Books]]'', vol. 44, no. 4 (24 February 2022), pp.&nbsp;29–32. "Nuclear strategists systematically underestimate the chances of nuclear accident... [T]here have been too many close calls for accidental use to be discounted." (p.&nbsp;32.)
* David Wright and Cameron Tracy, "Over-hyped: Physics dictates that [[hypersonic weapon]]s cannot live up to the grand promises made on their behalf", ''[[Scientific American]]'', vol. 325, no. 2 (August 2021), pp.&nbsp;64–71. "Failure to fully assess [the potential benefits and costs of hypersonic weapons] is a recipe for wasteful spending and increased global risk." (p.&nbsp;71.)
{{refend}}

== External links ==
{{Wikiquote}}
{{Wikinews category|Nuclear proliferation}}
{{Wikibooks|The Atomic Age}}
{{Commons|Nuclear weapons}}
* [http://nuclearweaponarchive.org/ Nuclear Weapon Archive from Carey Sublette]: reliable source, has links to other sources and an informative [https://nuclearweaponarchive.org/Nwfaq/Nfaq0.html FAQ].
* The [https://fas.org/ Federation of American Scientists] ({{Webarchive|url=https://web.archive.org/web/19961018095317/https://fas.org/ |date=October 18, 1996 }}) provides information on weapons of mass destruction, including [https://fas.org/nuke/ nuclear weapons] and their [https://web.archive.org/web/20150329105730/http://fas.org/nuke/intro/nuke/effects.htm effects]
* [http://alsos.wlu.edu/ Alsos Digital Library for Nuclear Issues] ({{Webarchive|url=https://web.archive.org/web/20010302000827/http://alsos.wlu.edu/ |date=March 2, 2001 }}) – contains resources related to nuclear weapons, including a historical and technical overview and searchable bibliography of web and print resources
* Video archive of [https://archive.today/20121205014623/http://sonicbomb.com/modules.php?name=Content&pa=showpage&pid=39 US, Soviet, UK, Chinese and French Nuclear Weapon Testing] at [https://www.sonicbomb.com/ sonicbomb.com]
* [http://www.nuclearmuseum.org/ The National Museum of Nuclear Science & History (United States)] ({{Webarchive|url=https://web.archive.org/web/20210327181530/http://www.nuclearmuseum.org/ |date=March 27, 2021 }}) – located in New Mexico; a Smithsonian Affiliate Museum
* [http://www.ibiblio.org/rcip/nuclear.html Nuclear Emergency and Radiation Resources] ({{Webarchive|url=https://web.archive.org/web/20210515170516/http://www.ibiblio.org/rcip/nuclear.html |date=May 15, 2021 }})
* [https://web.archive.org/web/20090209155804/http://atomicarchive.com/History/mp/index.shtml The Manhattan Project: Making the Atomic Bomb] at AtomicArchive.com
* [http://www.lanl.gov/history/ Los Alamos National Laboratory: History] ({{Webarchive|url=https://web.archive.org/web/20090115230637/http://www.lanl.gov/history/ |date=January 15, 2009 }})—US nuclear history
* [https://www.pbs.org/wgbh/americanexperience/films/bomb/ ''Race for the Superbomb''] , PBS website on the history of the H-bomb
* [https://web.archive.org/web/20210322065839/http://www.voshn.com/ Recordings of recollections of the victims of Hiroshima and Nagasaki]
* [https://web.archive.org/web/20150812050030/http://www.wilsoncenter.org/program/NPIHP The Woodrow Wilson Center's Nuclear Proliferation International History Project] or NPIHP is a global network of individuals and institutions engaged in the study of international nuclear history through archival documents, oral history interviews and other empirical sources.
* [http://nuclearsecrecy.com/nukemap/ NUKEMAP3D] ({{Webarchive|url=https://web.archive.org/web/20150828053318/http://nuclearsecrecy.com/nukemap/ |date=August 28, 2015 }}) – a 3D nuclear weapons effects simulator powered by Google Maps.

{{United States nuclear devices}}
{{French nuclear missiles}}
{{Strategic nuclear weapon systems of the United Kingdom}}
{{Nuclear technology}}
{{Nuclear and radiation accidents and incidents}}
{{Authority control}}

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