A nuclear weapon (also called an atom bomb, nuke, atomic bomb, nuclear warhead, A-bomb, or nuclear bomb) is an explosive device that derives its destructive force from nuclear reaction
s, either fission
(fission bomb) or from a combination of fission and fusion
reactions (thermonuclear bomb
). Both bomb types release large quantities of energy from relatively small amounts of matter.
The first test
of a fission ("atomic") bomb released an amount of energy approximately equal to .
The first thermonuclear ("hydrogen") bomb test
released energy approximately equal to . Nuclear bombs have had yield
s between 10 tons TNT (the W54
) and 50 megatons for the Tsar Bomba
(see TNT equivalent
). A thermonuclear weapon weighing little more than can release energy equal to more than .
A nuclear device no larger than traditional bombs can devastate an entire city by blast, fire, and radiation
. Since they are weapons of mass destruction
, the proliferation
of nuclear weapons is a focus of international relations
policy. Nuclear weapons have been deployed twice in war, by the United States against the Japanese cities Hiroshima and Nagasaki in 1945
during World War II
Testing and deployment of nuclear weapons
Nuclear weapons have been used twice in war
, both times by the United States
near the end of World War II
. On August 6, 1945, the U.S. Army Air Forces
detonated a uranium
gun-type fission bomb
nicknamed "Little Boy
" over the Japanese city of Hiroshima
; three days later, on August 9, the U.S. Army Air Forces 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 civilians
and military personnel
. The ethics of these bombings and their role in Japan's surrender
are subjects of debate
Since the atomic bombings of Hiroshima and Nagasaki
, nuclear weapons have been detonated over 2,000 times for testing
and demonstration. Only 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
, the Soviet Union
(succeeded as a nuclear power by Russia
), the United Kingdom
, and North Korea
is believed to possess nuclear weapons, though, in a policy of deliberate ambiguity
, it does not acknowledge having them. Germany
and the Netherlands
are nuclear weapons sharing
is the only country to have independently developed
and then renounced and dismantled
its nuclear weapons.
The Treaty on the Non-Proliferation of Nuclear Weapons
aims to reduce the spread of nuclear weapons, but its effectiveness has been questioned. Modernisation of weapons continues to this day.
, principal leader of the Manhattan Project
, often referred to as the "father of the atomic bomb".]]
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.
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 nucleus
of the atom, just as it does with fusion weapons.
In fission weapons, a mass of fissile material
) is forced into 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 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
[Hansen, Chuck. ''U.S. Nuclear Weapons: The Secret History.'' San Antonio, TX: Aerofax, 1988; and the more-updated Hansen, Chuck,]
Swords of Armageddon: U.S. Nuclear Weapons Development since 1945
" (CD-ROM & download available). PDF. 2,600 pages, Sunnyvale, California, Chuklea Publications, 1995, 2007. (2nd Ed.)
All fission reactions generate fission products
, the remains of the split atomic nuclei. Many fission products are either highly 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
. Less commonly used has been uranium-233
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.
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 weapons or more colloquially as hydrogen bombs (abbreviated as H-bombs), as they rely on fusion reactions between isotopes of hydrogen
). 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.
Only six countries—United States
, United Kingdom, China, France, and India
—have conducted thermonuclear weapon tests. Whether India has detonated a "true" multi-staged thermonuclear weapon
is controversial. North Korea
claims to have tested a fusion weapon , though this claim is disputed. 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 is more efficient.
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
, 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.
Virtually all thermonuclear weapons deployed today use the "two-stage" design described above, 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, in contrast to fission bombs, which are limited in their explosive force. The largest nuclear weapon ever detonated, the Tsar Bomba
of the USSR, which released an energy equivalent of over , was a three-stage weapon. Most thermonuclear weapons are considerably smaller than this, due to practical constraints from missile warhead space and weight requirements.
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
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.
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.
Some nuclear weapons are designed for special purposes; a neutron bomb
is a thermonuclear weapon that yields a relatively small explosion but a relatively large amount of neutron radiation
; such a device could theoretically be used to cause massive casualties while leaving infrastructure mostly intact and creating a minimal amount of fallout. The detonation of any nuclear weapon is accompanied by a blast of neutron radiation
. Surrounding a nuclear weapon with suitable materials (such as cobalt
) 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 against that enemy. Because the effect is produced by high altitude nuclear detonations, it can produce damage to electronics over a wide, even continental, geographical area.
Research has been done into the possibility of 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".
, 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.
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. However, the U.S. 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. A fourth generation nuclear weapon design
is related to, and relies upon, the same principle as antimatter-catalyzed nuclear pulse propulsion
Most variation in nuclear weapon design
is for the purpose of achieving different yields for different situations
, and in manipulating design elements to attempt to minimize weapon size.
of the Russian Strategic Rocket Forces
; 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 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.
The simplest method for delivering a nuclear weapon is a gravity bomb
dropped from aircraft
; this was the method used by the United States against Japan. 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 U.S. nuclear warheads, for example, are free-fall gravity bombs, namely the B61
Preferable from a strategic point of view is a nuclear weapon mounted on a missile
, which can use a 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.
have involved the most variety of delivery types, including not only gravity bombs and missiles but also artillery
shells, land mines
, and nuclear depth charge
s and torpedoes
for anti-submarine warfare
. An atomic 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.
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 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 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.
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 weapons
.'' Nuclear weapons for use on a battle
field in military situations are called ''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 have questioned the usefulness of such weapons in the current military climate. According to an 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.
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 U.S. and the Soviet Union
. 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 international stability
. Some prominent 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, and Waltz, who was somewhat more non-interventionist
"The Spread of Nuclear Weapons: More May Better,"
''Adelphi Papers'', no. 171 (London: International Institute for Strategic Studies, 1981).
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
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, 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.
[See, for example: Feldman, Noah.]
Islam, Terror and the Second Nuclear Age
," ''New York Times Magazine'' (October 29, 2006).
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
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.".
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."
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."
Governance, control, and law
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
. Despite controls and regulations governing nuclear weapons, there is an inherent danger of "accidents, mistakes, false alarms, blackmail, theft, and sabotage".
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.
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
which prohibits all testing of nuclear weapons. A testing ban imposes a significant hindrance to nuclear arms development by any complying country.
[Richelson, Jeffrey. ''Spying on the bomb: American nuclear intelligence from Nazi Germany to Iran and North Korea.'' New York: Norton, 2006.]
The Treaty requires the ratification by 44 specific states before it can go into force; , the ratification of eight of these states is still required.
[Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (2010).]
Status of Signature and Ratification
". 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.
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
, START II
(never ratified), SORT
, and New START
, as well as non-binding agreements such as SALT I
and the Presidential Nuclear Initiatives 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.
In 1996, the International Court of Justice
, the highest court of the United Nations, issued an Advisory Opinion concerned with the "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
, 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.
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 not to be the case
as the program had been discontinued). In 1981, Israel had bombed a nuclear reactor
being constructed in Osirak
, in what it called an attempt to halt Iraq's previous nuclear arms ambitions; in 2007, Israel 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 and/or research reactors to assist nuclear weapons development or to contribute to their supplies of nuclear explosives from military reactors.
The two tied-for-lowest points for the Doomsday Clock
have been in 1953, when the Clock was set to two minutes until midnight after the U.S. and the Soviet Union began testing hydrogen bombs, and in 2018, following the failure of world leaders to address tensions relating to nuclear weapons and climate change issues.
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 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.
Only one country—South Africa—has ever fully renounced nuclear weapons they had independently developed. The former Soviet republics of Belarus
, 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, 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 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".
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. 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
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
. A CNN
poll from April 2010 indicated that the American public was nearly evenly split on the issue.
Some analysts have argued that nuclear weapons have made the world relatively safer, with peace through deterrence
and through the stability–instability paradox
, including in south Asia. 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
But former Secretary Henry Kissinger
says 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". 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".
As of early 2019, more than 90% of world's 13,865 nuclear weapons were owned by Russia and the United States.
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 General Assembly
in July 1997.
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
and 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.
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 Japan's surrender
and the U.S.'s 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.
[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.]
Notable nuclear weapons accidents
* August 21, 1945: While conducting impromptu experiments on a third core (an alloy of plutonium and gallium) which had been prepared for atomic warfare at Los Alamos National Laboratory
, physicist Harry Daghlian
received a lethal dose of radiation. He died on September 15, 1945.
* May 21, 1946: While conducting further impromptu experiments on the third plutonium core at Los Alamos National Laboratory, physicist Louis Slotin
received a lethal dose of radiation. He died on May 30, 1946. After these 2 incidents, the core was used to construct a bomb for use on the Nevada Test Range.
* February 13, 1950: a Convair B-36B crashed
in northern British Columbia
after jettisoning a Mark IV atomic bomb
. This was the first such nuclear weapon loss
in history. The accident was designated a "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.
* May 22, 1957: a 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 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.
* 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 bombs broke up in mid-air, dropping its nuclear payload in the process.
* 1965 Philippine Sea A-4 crash
, where a Skyhawk
attack aircraft with a nuclear weapon fell into the sea.
The pilot, the aircraft, and the B43 nuclear bomb
were never recovered. It was not until 1989 that the Pentagon
revealed the loss of the one-megaton bomb.
* January 17, 1966: the 1966 Palomares B-52 crash
occurred when a B-52G bomber
of the USAF
collided with a KC-135 tanker
during 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.
Of the four Mk28
type hydrogen bombs
the B-52G carried, 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 (0.78 square mile) area by radioactive plutonium
. The fourth, which fell into the Mediterranean Sea
, was recovered intact after a 2½-month-long search.
* January 21, 1968: the 1968 Thule Air Base B-52 crash
involved a United States Air Force
(USAF) 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
, causing the nuclear payload to rupture and disperse, which resulted in widespread radioactive contamination
. One of the bombs remains lost.
* September 18–19, 1980: the Damascus Accident
, occurred in Damascus, Arkansas, where a 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 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.
Nuclear testing and fallout
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 ''Lucky Dragon
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".
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.
, the U.S. is the only nation that compensates nuclear test victims. Since the Radiation Exposure Compensation Act
of 1990, more than $1.38 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.
In addition, leakage of byproducts of nuclear weapon production into groundwater has been an ongoing issue, particularly at the Hanford site
Effects of nuclear explosions
Effects of nuclear explosions on human health
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
People near the Hiroshima explosion and who managed to survive the explosion subsequently suffered a variety of medical effects:
* Initial stage—the first 1–9 weeks, in which are the greatest number of deaths, with 90% due to thermal injury and/or blast effects and 10% due to super-lethal radiation
* 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+ 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+ 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.
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.
Staying indoors until after the most hazardous fallout isotope
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.
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 "Japanese 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".
[Jim Falk (1982). ''Global Fission: The Battle Over Nuclear Power'', Oxford University Press, pp. 96–97.]
In the United Kingdom, the first Aldermaston March
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 Research Establishment
close to Aldermaston
, England, to demonstrate their opposition to nuclear weapons.
The Aldermaston marches continued into the late 1960s when tens of thousands of people took part in the four-day marches.
In 1959, a letter in the ''Bulletin of the Atomic Scientists'' was the start of a successful campaign to stop the Atomic Energy Commission
dumping radioactive waste
in the sea 19 kilometres from Boston
. 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.
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.
A resurgence of interest occurred amid European and American fears of nuclear war
in the 1980s.
Costs and technology spin-offs
According to an audit by the Brookings Institution
, between 1940 and 1996, the U.S. spent $ in present-day terms on nuclear weapons programs. 57 percent of which was spent on building nuclear weapons delivery
systems. 6.3 percent of the total, $ in present-day terms, was spent on environmental remediation
and nuclear waste management
, for example cleaning up the Hanford site
, and 7 percent of the total, $ was spent on making nuclear weapons themselves.
Peaceful nuclear explosions 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. 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. The stalled Comprehensive Nuclear-Test-Ban Treaty
of 1996 would prohibit all nuclear explosions, regardless of whether they are for peaceful purposes or not.
History of development
* Cobalt bomb
* Cosmic bomb (phrase)
* Cuban Missile Crisis
* Dirty bomb
* Induced gamma emission
* List of nuclear close calls
* List of nuclear weapons
* Nth Country Experiment
* Nuclear blackout
* Nuclear bunker buster
* Nuclear holocaust
* Nuclear weapons and the United Kingdom
* Nuclear weapons in popular culture
* Nuclear weapons of the United States
(Agency for the Prohibition of Nuclear Weapons in Latin America and the Caribbean)
* Three Non-Nuclear Principles
* Bethe, Hans Albrecht
. ''The Road from Los Alamos''. New York: Simon and Schuster, 1991.
* 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. The Effects of Nuclear Weapons (third edition).
' Washington, D.C.: U.S. Government Printing Office, 1977Available online (PDF).
'. Departments of the Army, Navy, and Air Force: Washington, D.C., 1996
* Hansen, Chuck
. ''U.S. Nuclear Weapons: The Secret History.'' Arlington, TX: Aerofax, 1988
* Hansen, Chuck,Swords of Armageddon: U.S. nuclear weapons development since 1945
(CD-ROM & download available). PDF. 2,600 pages, Sunnyvale, California, Chucklea Publications, 1995, 2007. (2nd Ed.)
* Holloway, David. ''Stalin and the Bomb''. New Haven: Yale University Press, 1994.
* The Manhattan Engineer District,The Atomic Bombings of Hiroshima and Nagasaki
* Jean-Hugues Oppel, ''Réveillez le président'', Éditions Payot et rivages, 2007 (). The book is a fiction about the nuclear weapons
of France; the book also contains about ten chapters on true historical incidents involving nuclear weapons and strategy.
* Smyth, Henry DeWolf
. Atomic Energy for Military Purposes.
' Princeton, NJ: Princeton University Press, 1945. (Smyth Report
the first declassified report by the US government on nuclear weapons)
* The Effects of Nuclear War
'. Office of Technology Assessment, May 1979.
* Rhodes, Richard
. ''Dark Sun: The Making of the Hydrogen Bomb''. New York: Simon and Schuster, 1995.
* Rhodes, Richard
. ''The Making of the Atomic Bomb
''. New York: Simon and Schuster, 1986
* Shultz, George P.
and Goodby, James E. ''The War that Must Never be Fought'', Hoover Press, 2015, .
* Weart, Spencer R.
''Nuclear Fear: A History of Images''. Cambridge, Massachusetts: Harvard University Press, 1988.
* Weart, Spencer R.
''The Rise of Nuclear Fear''. Cambridge, Massachusetts: Harvard University Press, 2012.
* 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. 62–67. "Current U.S. missile defense
plans are being driven largely by technology
. 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 reducing nuclear risks
—by blocking further cuts in nuclear arsenals and potentially spurring new deployments." (p. 67.)
* Michael T. Klare
, "Missile Mania: The death of the INF ntermediate-Range Nuclear Forces
Treaty f 1987
has escalated the arms race", ''The Nation
'', vol. 309, no. 6 (September 23, 2019), p. 4.
* 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. 150–161. Former U.S. Secretary of Energy Ernest Moniz
and former U.S. Senator Sam Nunn
write that "the old trategic
equilibrium" between the United States
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. 161.)
* Thomas Powers
, "The Nuclear Worrier" (review of Daniel Ellsberg
, ''The Doomsday Machine: Confessions of a Nuclear War
Planner'', New York, Bloomsbury, 2017, , 420 pp.), ''The New York Review of Books
'', vol. LXV, no. 1 (January 18, 2018), pp. 13–15.
* Eric Schlosser
, ''Command and Control: Nuclear Weapons, the Damascus Accident, and the Illusion of Safety
'', Penguin Press
, 2013, . 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.
Nuclear Weapon Archive from Carey Sublette
is a reliable source of information and has links to other sources and an informativ
* ThFederation of American Scientists
provide solid information on weapons of mass destruction, includinnuclear weapons
and theiAlsos Digital Library for Nuclear Issues
– contains many resources related to nuclear weapons, including a historical and technical overview and searchable bibliography of web and print resources.
* Video archive oUS, Soviet, UK, Chinese and French Nuclear Weapon Testing
asonicbomb.comThe National Museum of Nuclear Science & History (United States)
– located in Albuquerque, New Mexico; a Smithsonian Affiliate Museum
The Manhattan Project: Making the Atomic Bomb
Los Alamos National Laboratory: History
(U.S. nuclear history)
''Race for the Superbomb''
PBS website on the history of the H-bomb
Recordings of recollections of the victims of Hiroshima and NagasakiThe 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.
– a 3D nuclear weapons effects simulator powered by Google Maps.
Category:Weapons and ammunition introduced in 1945
Category:Articles containing video clips