Nuclear weapon

Nuclear weapon

Overview


A nuclear weapon is an explosive device that derives its destructive force from nuclear reaction
Nuclear reaction
In nuclear physics and nuclear chemistry, a nuclear reaction is semantically considered to be the process in which two nuclei, or else a nucleus of an atom and a subatomic particle from outside the atom, collide to produce products different from the initial particles...

s, either fission
Nuclear fission
In nuclear physics and nuclear chemistry, nuclear fission is a nuclear reaction in which the nucleus of an atom splits into smaller parts , often producing free neutrons and photons , and releasing a tremendous amount of energy...

 or a combination of fission and fusion
Nuclear fusion
Nuclear fusion is the process by which two or more atomic nuclei join together, or "fuse", to form a single heavier nucleus. This is usually accompanied by the release or absorption of large quantities of energy...

. Both reactions release vast quantities of energy from relatively small amounts of matter. The first fission ("atomic") bomb test released the same amount of energy as approximately 20,000 tons of TNT
TNT equivalent
TNT equivalent is a method of quantifying the energy released in explosions. The ton of TNT is a unit of energy equal to 4.184 gigajoules, which is approximately the amount of energy released in the detonation of one ton of TNT...

. The first thermonuclear ("hydrogen") bomb test released the same amount of energy as approximately 10,000,000 tons of TNT.

A modern thermonuclear weapon weighing little more than 2400 pounds (1,088.6 kg) can produce an explosive force comparable to the detonation of more than 1.2 million tons (1.1 million tonnes) of TNT.
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Timeline

1945   Manhattan Project: the Atomic Age begins when the United States successfully detonates a plutonium-based test nuclear weapon at the Trinity site near Alamogordo, New Mexico.

1945   World War II: Hiroshima is devastated when the atomic bomb "Little Boy" is dropped by the United States B-29 ''Enola Gay''. Around 70,000 people are killed instantly, and some tens of thousands die in subsequent years from burns and radiation poisoning.

1945   World War II: Nagasaki is devastated when an atomic bomb, ''Fat Man'', is dropped by the United States B-29 ''Bockscar''. 39,000 people are killed outright.

1945   The USSR's nuclear program receives plans for the United States plutonium bomb from Klaus Fuchs at the Los Alamos National Laboratory.

1952   The United Kingdom successfully tests a nuclear weapon.

1953   Cold War: U.S. President Dwight D. Eisenhower formally approves the top secret document National Security Council Paper No. 162/2, which states that the United States' arsenal of nuclear weapons must be maintained and expanded to counter the communist threat.

1955   Eighteen Nobel laureates sign the Mainau Declaration against nuclear weapons, later co-signed by thirty-four others.

1962   Cuban Missile Crisis: US President John F. Kennedy, after internal counsel from Dwight D. Eisenhower, announces that American reconnaissance planes have discovered Soviet nuclear weapons in Cuba, and that he has ordered a naval "quarantine" of the Communist nation.

1967   More than sixty nations sign the Outer Space Treaty banning nuclear weapons in space.

1971   Eighty-seven countries, including the US, UK, and USSR, sign the Seabed Treaty outlawing nuclear weapons in international waters.

 
Encyclopedia


A nuclear weapon is an explosive device that derives its destructive force from nuclear reaction
Nuclear reaction
In nuclear physics and nuclear chemistry, a nuclear reaction is semantically considered to be the process in which two nuclei, or else a nucleus of an atom and a subatomic particle from outside the atom, collide to produce products different from the initial particles...

s, either fission
Nuclear fission
In nuclear physics and nuclear chemistry, nuclear fission is a nuclear reaction in which the nucleus of an atom splits into smaller parts , often producing free neutrons and photons , and releasing a tremendous amount of energy...

 or a combination of fission and fusion
Nuclear fusion
Nuclear fusion is the process by which two or more atomic nuclei join together, or "fuse", to form a single heavier nucleus. This is usually accompanied by the release or absorption of large quantities of energy...

. Both reactions release vast quantities of energy from relatively small amounts of matter. The first fission ("atomic") bomb test released the same amount of energy as approximately 20,000 tons of TNT
TNT equivalent
TNT equivalent is a method of quantifying the energy released in explosions. The ton of TNT is a unit of energy equal to 4.184 gigajoules, which is approximately the amount of energy released in the detonation of one ton of TNT...

. The first thermonuclear ("hydrogen") bomb test released the same amount of energy as approximately 10,000,000 tons of TNT.

A modern thermonuclear weapon weighing little more than 2400 pounds (1,088.6 kg) can produce an explosive force comparable to the detonation of more than 1.2 million tons (1.1 million tonnes) of TNT. Thus, even a small nuclear device no larger than traditional bombs can devastate an entire city by blast, fire and radiation
Radiation
In physics, radiation is a process in which energetic particles or energetic waves travel through a medium or space. There are two distinct types of radiation; ionizing and non-ionizing...

. Nuclear weapons are considered weapons of mass destruction
Weapons of mass destruction
A weapon of mass destruction is a weapon that can kill and bring significant harm to a large number of humans and/or cause great damage to man-made structures , natural structures , or the biosphere in general...

, and their use and control
Nuclear proliferation
Nuclear proliferation is a term now used to describe the spread of nuclear weapons, fissile material, and weapons-applicable nuclear technology and information, to nations which are not recognized as "Nuclear Weapon States" by the Treaty on the Nonproliferation of Nuclear Weapons, also known as the...

 have been a major focus of international relations
International relations
International relations is the study of relationships between countries, including the roles of states, inter-governmental organizations , international nongovernmental organizations , non-governmental organizations and multinational corporations...

 policy since their debut.

Only two nuclear weapons
Atomic bombings of Hiroshima and Nagasaki
During the final stages of World War II in 1945, the United States conducted two atomic bombings against the cities of Hiroshima and Nagasaki in Japan, the first on August 6, 1945, and the second on August 9, 1945. These two events are the only use of nuclear weapons in war to date.For six months...

 have been used in the course of warfare, both by the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 near the end of World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

. On 6 August 1945, a uranium
Uranium
Uranium is a silvery-white metallic chemical element in the actinide series of the periodic table, with atomic number 92. It is assigned the chemical symbol U. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons...

 gun-type device code-named "Little Boy
Little Boy
"Little Boy" was the codename of the atomic bomb dropped on Hiroshima on August 6, 1945 by the Boeing B-29 Superfortress Enola Gay, piloted by Colonel Paul Tibbets of the 393rd Bombardment Squadron, Heavy, of the United States Army Air Forces. It was the first atomic bomb to be used as a weapon...

" was detonated over the Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

ese city of Hiroshima
Hiroshima
is the capital of Hiroshima Prefecture, and the largest city in the Chūgoku region of western Honshu, the largest island of Japan. It became best known as the first city in history to be destroyed by a nuclear weapon when the United States Army Air Forces dropped an atomic bomb on it at 8:15 A.M...

. Three days later, on 9 August, a plutonium
Plutonium
Plutonium is a transuranic radioactive chemical element with the chemical symbol Pu and atomic number 94. It is an actinide metal of silvery-gray appearance that tarnishes when exposed to air, forming a dull coating when oxidized. The element normally exhibits six allotropes and four oxidation...

 implosion-type device code-named "Fat Man
Fat Man
"Fat Man" is the codename for the atomic bomb that was detonated over Nagasaki, Japan, by the United States on August 9, 1945. It was the second of the only two nuclear weapons to be used in warfare to date , and its detonation caused the third man-made nuclear explosion. The name also refers more...

" was exploded over Nagasaki, Japan. These two bombings resulted in the deaths of approximately 200,000 Japanese people—mostly civilians—from acute injuries sustained from the explosions. The role of the bombings in Japan's surrender, and their ethical status, remain the subject of scholarly and popular debate
Debate over the atomic bombings of Hiroshima and Nagasaki
The debate over the atomic bombings of Hiroshima and Nagasaki concerns the ethical, legal and military controversies surrounding the United States' atomic bombings of Hiroshima and Nagasaki on 6 August and 9 August 1945 at the close of the Second World War...

.

Since the bombings of Hiroshima and Nagasaki, nuclear weapons have been detonated on over two thousand occasions for testing purposes and demonstrations. Only a few nations possess such weapons or are suspected of seeking them. The only countries known to have detonated nuclear weapons—and that acknowledge possessing such weapons—are (chronologically by date of first test) the United States
United States and weapons of mass destruction
The United States is known to have possessed three types of weapons of mass destruction: nuclear weapons, chemical weapons and biological weapons. The U.S. is the only country to have used nuclear weapons in combat. The U.S. also used chemical weapons in World War I...

, the Soviet Union
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....

 (succeeded as a nuclear power by Russia
Russia and weapons of mass destruction
Russia possesses the largest stockpiles of weapons of mass destruction in the world. The country declared an arsenal of 39,967 tons of chemical weapons in 1997, of which 48% have been destroyed. The Federation of American Scientists, a renowned organization for assessing nuclear weapon...

), the United Kingdom
United Kingdom and weapons of mass destruction
The United Kingdom possesses, or has possessed, a variety of weapons of mass destruction, including nuclear, biological, and chemical weapons. The United Kingdom is one of the five official nuclear weapon states under the Nuclear Non-Proliferation Treaty and has an independent nuclear deterrent...

, France
France and weapons of mass destruction
France is known to have an arsenal of weapons of mass destruction. France is one of the five "Nuclear Weapons States" under the Nuclear Non-Proliferation Treaty; but is not known to possess or develop any chemical or biological weapons. France was the fourth country to test an independently...

, the People's Republic of China, India
India and weapons of mass destruction
India possesses nuclear weapons and maintains short- and intermediate-range ballistic missiles, nuclear-capable aircraft, surface ships, and submarines under development as possible delivery systems and platforms...

, Pakistan
Pakistan and weapons of mass destruction
Pakistan began focusing on nuclear weapons development in January 1972 under the leadership of Prime Minister Zulfiqar Ali Bhutto, who delegated the program to the Chairman of PAEC Munir Ahmad Khan...

, and North Korea
North Korea and weapons of mass destruction
North Korea has declared that it has nuclear weapons and is believed by many to have nuclear weapons. The CIA assesses that North Korea also has a substantial arsenal of chemical weapons...

. In addition, Israel
Israel and weapons of mass destruction
Israel is widely believed to possess weapons of mass destruction, and to be one of four nuclear-armed countries not recognized as a Nuclear Weapons State by the Nuclear Non-Proliferation Treaty...

 is also widely believed to possess nuclear weapons, though it does not acknowledge having them. One state, South Africa
South Africa and weapons of mass destruction
From the 1960s to the 1980s, South Africa pursued research into weapons of mass destruction, including nuclear, biological, and chemical weapons. Six nuclear weapons were assembled...

, has admitted to having previous fabricated nuclear weapons in the past, but has since disassembled their arsenal and submitted to international safeguards.

Types



There are two basic types of nuclear weapons: those which derive the majority of their energy from nuclear fission
Nuclear fission
In nuclear physics and nuclear chemistry, nuclear fission is a nuclear reaction in which the nucleus of an atom splits into smaller parts , often producing free neutrons and photons , and releasing a tremendous amount of energy...

 reactions alone, and those which use fission reactions to begin nuclear fusion
Nuclear fusion
Nuclear fusion is the process by which two or more atomic nuclei join together, or "fuse", to form a single heavier nucleus. This is usually accompanied by the release or absorption of large quantities of energy...

 reactions that produce a large amount of the total energy output.

Fission weapons


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
Misnomer
A misnomer is a term which suggests an interpretation that is known to be untrue. Such incorrect terms sometimes derive their names because of the form, action, or origin of the subject becoming named popularly or widely referenced—long before their true natures were known.- Sources of misnomers...

, however, as their energy comes specifically from the nucleus of the atom.

In fission weapons, a mass of fissile
Fissile
In nuclear engineering, a fissile material is one that is capable of sustaining a chain reaction of nuclear fission. By definition, fissile materials can sustain a chain reaction with neutrons of any energy. The predominant neutron energy may be typified by either slow neutrons or fast neutrons...

 material (enriched uranium
Enriched uranium
Enriched uranium is a kind of uranium in which the percent composition of uranium-235 has been increased through the process of isotope separation. Natural uranium is 99.284% 238U isotope, with 235U only constituting about 0.711% of its weight...

 or plutonium
Plutonium
Plutonium is a transuranic radioactive chemical element with the chemical symbol Pu and atomic number 94. It is an actinide metal of silvery-gray appearance that tarnishes when exposed to air, forming a dull coating when oxidized. The element normally exhibits six allotropes and four oxidation...

) is assembled into a supercritical mass
Critical mass
A critical mass is the smallest amount of fissile material needed for a sustained nuclear chain reaction. The critical mass of a fissionable material depends upon its nuclear properties A critical mass is the smallest amount of fissile material needed for a sustained nuclear chain reaction. The...

—the amount of material needed to start an exponentially growing
Exponential growth
Exponential growth occurs when the growth rate of a mathematical function is proportional to the function's current value...

 nuclear chain reaction
Nuclear chain reaction
A nuclear chain reaction occurs when one nuclear reaction causes an average of one or more nuclear reactions, thus leading to a self-propagating number of these reactions. The specific nuclear reaction may be the fission of heavy isotopes or the fusion of light isotopes...

—either by shooting one piece of sub-critical material into another (the "gun" method) or by compressing a sub-critical sphere of material using chemical explosives
Explosive material
An explosive material, also called an explosive, is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure...

 to many times its original density (the "implosion" method). The latter approach is considered more sophisticated than the former and only the latter approach can be used if the fissile material is plutonium.

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 less than a ton of TNT upwards of 500,000 tons (500 kilotons) of TNT.

All fission reactions necessarily generate fission products, the radioactive remains of the atomic nuclei split by the fission reactions. Many fission products are either highly radioactive (but short-lived) or moderately radioactive (but long-lived), and as such are a serious form of radioactive contamination
Radioactive contamination
Radioactive contamination, also called radiological contamination, is radioactive substances on surfaces, or within solids, liquids or gases , where their presence is unintended or undesirable, or the process giving rise to their presence in such places...

 if not fully contained. Fission products are the principal radioactive component of nuclear fallout
Nuclear fallout
Fallout is the residual radioactive material propelled into the upper atmosphere following a nuclear blast, so called because it "falls out" of the sky after the explosion and shock wave have passed. It commonly refers to the radioactive dust and ash created when a nuclear weapon explodes...

.

The most commonly used fissile materials for nuclear weapons applications have been uranium-235
Uranium-235
- References :* .* DOE Fundamentals handbook: Nuclear Physics and Reactor theory , .* A piece of U-235 the size of a grain of rice can produce energy equal to that contained in three tons of coal or fourteen barrels of oil. -External links:* * * one of the earliest articles on U-235 for the...

 and plutonium-239
Plutonium-239
Plutonium-239 is an isotope of plutonium. Plutonium-239 is the primary fissile isotope used for the production of nuclear weapons, although uranium-235 has also been used and is currently the secondary isotope. Plutonium-239 is also one of the three main isotopes demonstrated usable as fuel in...

. Less commonly used has been uranium-233
Uranium-233
Uranium-233 is a fissile isotope of uranium, bred from Thorium as part of the thorium fuel cycle. It has been used in a few nuclear reactors and has been proposed for much wider use as a nuclear fuel. It has a half-life of 160,000 years....

. Neptunium-237 and a number of isotopes of americium
Americium
Americium is a synthetic element that has the symbol Am and atomic number 95. This transuranic element of the actinide series is located in the periodic table below the lanthanide element europium, and thus by analogy was named after another continent, America.Americium was first produced in 1944...

 may be usable for nuclear explosives as well, but it is not clear that this has ever been actually implemented, and even their plausible use in nuclear weapons is a matter of scientific dispute.

Fusion weapons


The other basic type of nuclear weapon produces a large amount of its energy through 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
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

 (deuterium
Deuterium
Deuterium, also called heavy hydrogen, is one of two stable isotopes of hydrogen. It has a natural abundance in Earth's oceans of about one atom in of hydrogen . Deuterium accounts for approximately 0.0156% of all naturally occurring hydrogen in Earth's oceans, while the most common isotope ...

 and tritium
Tritium
Tritium is a radioactive isotope of hydrogen. The nucleus of tritium contains one proton and two neutrons, whereas the nucleus of protium contains one proton and no neutrons...

). However, all such weapons derive a significant portion, and sometimes a majority, of their energy from fission. This is because a fission weapon is required as a "trigger" for the fusion reactions, and the fusion reactions can themselves trigger additional fission reactions.

Only six countries—United States, Russia, United Kingdom, People's Republic of China, France and India—have conducted thermonuclear weapon tests. (Whether India has detonated a "true", multi-staged thermonuclear weapon is controversial.) All thermonuclear weapons are considered to be much more difficult to successfully design and execute than primitive fission weapons.

Thermonuclear bombs work by using the energy of a fission bomb to compress and heat fusion fuel. In the Teller-Ulam design
Teller-Ulam design
The Teller–Ulam design is the nuclear weapon design concept used in most of the world's nuclear weapons. It is colloquially referred to as "the secret of the hydrogen bomb" because it employs hydrogen fusion, though in most applications the bulk of its destructive energy comes from uranium fission,...

, which accounts for all multi-megaton yield hydrogen bombs, this is accomplished by placing a fission bomb and fusion fuel (tritium
Tritium
Tritium is a radioactive isotope of hydrogen. The nucleus of tritium contains one proton and two neutrons, whereas the nucleus of protium contains one proton and no neutrons...

, deuterium
Deuterium
Deuterium, also called heavy hydrogen, is one of two stable isotopes of hydrogen. It has a natural abundance in Earth's oceans of about one atom in of hydrogen . Deuterium accounts for approximately 0.0156% of all naturally occurring hydrogen in Earth's oceans, while the most common isotope ...

, or lithium deuteride) in proximity within a special, radiation-reflecting container. When the fission bomb is detonated, gamma and X-ray
X-ray
X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...

s emitted first compress the fusion fuel, then heat it to thermonuclear temperatures. The ensuing fusion reaction creates enormous numbers of high-speed neutron
Neutron
The neutron is a subatomic hadron particle which has the symbol or , no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen, nuclei of atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of...

s, which can then induce fission in materials not normally prone to it, such as depleted uranium
Depleted uranium
Depleted uranium is uranium with a lower content of the fissile isotope U-235 than natural uranium . Uses of DU take advantage of its very high density of 19.1 g/cm3...

. 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.

By chaining together numerous stages with increasing amounts of fusion fuel, thermonuclear weapons can be made to an almost arbitrary yield; the largest ever detonated (the Tsar Bomba
Tsar Bomba
Tsar Bomba is the nickname for the AN602 hydrogen bomb, the most powerful nuclear weapon ever detonated. It was also referred to as Kuz'kina Mat , in this usage meaning "something that has not been seen before"....

 of the USSR
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....

) released an energy equivalent of over 50 million tons (50 megatons
TNT equivalent
TNT equivalent is a method of quantifying the energy released in explosions. The ton of TNT is a unit of energy equal to 4.184 gigajoules, which is approximately the amount of energy released in the detonation of one ton of TNT...

) of TNT. Most thermonuclear weapons are considerably smaller than this, due to practical constraints arising from the space and weight requirements of missile warheads.

Fusion reactions do not create fission products, and thus contribute far less to the creation of nuclear fallout than fission reactions. However, because all thermonuclear weapons contain at least one fission stage, and many high-yield thermonuclear devices have a final fission stage from depleted uranium, thermonuclear weapons can generate at least as much nuclear fallout as fission-only weapons, if not substantially more.

Other types


There are other types of nuclear weapons as well. For example, a boosted fission weapon
Boosted fission weapon
A boosted fission weapon usually refers to a type of nuclear bomb that uses a small amount of fusion fuel to increase the rate, and thus yield, of a fission reaction. The neutrons released by the fusion reactions add to the neutrons released in the fission, as well as inducing the fission reactions...

 is a fission bomb which increases its explosive yield through a small amount 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.

Some weapons are designed for special purposes; a neutron bomb
Neutron bomb
A neutron bomb or enhanced radiation weapon or weapon of reinforced radiation is a type of thermonuclear weapon designed specifically to release a large portion of its energy as energetic neutron radiation rather than explosive energy...

 is a thermonuclear weapon that yields a relatively small explosion but a relatively large amount of neutron radiation
Radiation
In physics, radiation is a process in which energetic particles or energetic waves travel through a medium or space. There are two distinct types of radiation; ionizing and non-ionizing...

; 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
Neutron radiation
Neutron radiation is a kind of ionizing radiation which consists of free neutrons. A result of nuclear fission or nuclear fusion, it consists of the release of free neutrons from atoms, and these free neutrons react with nuclei of other atoms to form new isotopes, which, in turn, may produce...

. Surrounding a nuclear weapon with suitable materials (such as cobalt
Cobalt
Cobalt is a chemical element with symbol Co and atomic number 27. It is found naturally only in chemically combined form. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal....

 or gold
Gold
Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...

) creates a weapon known as a salted bomb
Salted bomb
A salted bomb is a variation of a nuclear weapon designed to produce enhanced quantities of radioactive fallout, rendering a large area uninhabitable...

. This device can produce exceptionally large quantities of radioactive contamination
Radioactive contamination
Radioactive contamination, also called radiological contamination, is radioactive substances on surfaces, or within solids, liquids or gases , where their presence is unintended or undesirable, or the process giving rise to their presence in such places...

.

Research has been done into the possibility of pure fusion bomb
Pure fusion weapon
A pure fusion weapon is a hypothetical hydrogen bomb design that does not need a fission "primary" explosive to ignite the fusion of deuterium and tritium, two heavy isotopes of hydrogen . Such a weapon would require no fissile material and would therefore be much easier to build in secret than...

s: nuclear weapons that consisted of fusion reactions without requiring a fission bomb to initiate them. Such a weapon would potentially prove to be a simpler path to thermonuclear weapons than one requiring the development of fission weapons first, and pure fusion weapons would create significantly less nuclear fallout than other thermonuclear weapons, as they would not disperse fission products. In 1998, the United States Department of Energy
United States Department of Energy
The United States Department of Energy is a Cabinet-level department of the United States government concerned with the United States' policies regarding energy and safety in handling nuclear material...

 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."

Most variation in nuclear weapon design
Nuclear weapon design
Nuclear weapon designs are physical, chemical, and engineering arrangements that cause the physics package of a nuclear weapon to detonate. There are three basic design types...

 is for the purpose of achieving different yields for different situations, and in manipulating design elements to attempt to minimize weapon size.

Weapons delivery



Nuclear weapons delivery
Nuclear weapons delivery
Nuclear weapons delivery is the technology and systems used to place a nuclear weapon at the position of detonation, on or near its target. Several methods have been developed to carry out this task....

—the technology and systems used to bring a nuclear weapon to its target—is an important aspect of nuclear weapons relating both to nuclear weapon design
Nuclear weapon design
Nuclear weapon designs are physical, chemical, and engineering arrangements that cause the physics package of a nuclear weapon to detonate. There are three basic design types...

 and nuclear strategy
Nuclear warfare
Nuclear warfare, or atomic warfare, is a military conflict or political strategy in which nuclear weaponry is detonated on an opponent. Compared to conventional warfare, nuclear warfare can be vastly more destructive in range and extent of damage...

. Additionally, development and maintenance of delivery options is among the most resource-intensive aspects of a nuclear weapons program: according to one estimate, deployment costs accounted for 57% of the total financial resources spent by the United States in relation to nuclear weapons since 1940.

Historically the first method of delivery, and the method used in the two nuclear weapons actually used in war
War
War is a state of organized, armed, and often prolonged conflict carried on between states, nations, or other parties typified by extreme aggression, social disruption, and usually high mortality. War should be understood as an actual, intentional and widespread armed conflict between political...

fare, was as a gravity bomb
Gravity bomb
An unguided bomb, also known as a free-fall bomb, gravity bomb, dumb bomb, or iron bomb, is a conventional aircraft-delivered bomb that does not contain a guidance system and hence, simply follows a ballistic trajectory....

, dropped from bomber
Bomber
A bomber is a military aircraft designed to attack ground and sea targets, by dropping bombs on them, or – in recent years – by launching cruise missiles at them.-Classifications of bombers:...

 aircraft
Aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...

. This method is usually the first developed by countries as it does not place many restrictions on the size of the weapon and weapon miniaturization is something which requires considerable weapons design knowledge. It does, however, limit the range of attack, the response time to an impending attack, and the number of weapons which can be fielded at any given time.

With the advent of miniaturization, nuclear bombs can be delivered by both strategic bomber
Strategic bomber
A strategic bomber is a heavy bomber aircraft designed to drop large amounts of ordnance onto a distant target for the purposes of debilitating an enemy's capacity to wage war. Unlike tactical bombers, which are used in the battle zone to attack troops and military equipment, strategic bombers are...

s and tactical fighter-bomber
Fighter-bomber
A fighter-bomber is a fixed-wing aircraft with an intended primary role of light tactical bombing and also incorporating certain performance characteristics of a fighter aircraft. This term, although still used, has less significance since the introduction of rockets and guided missiles into aerial...

s, allowing an air force to use its current fleet with little or no modification. This method may still be considered the primary means of nuclear weapons delivery; the majority of U.S. nuclear warheads, for example, are free-fall gravity bombs, namely the B61
B61 nuclear bomb
The B61 nuclear bomb is the primary thermonuclear weapon in the U.S. Enduring Stockpile following the end of the Cold War. It is an intermediate yield strategic and tactical nuclear weapon featuring a two-stage radiation implosion design....

.

More preferable from a strategic point of view is a nuclear weapon mounted onto a missile
Missile
Though a missile may be any thrown or launched object, it colloquially almost always refers to a self-propelled guided weapon system.-Etymology:The word missile comes from the Latin verb mittere, meaning "to send"...

, which can use a ballistic
Ballistics
Ballistics is the science of mechanics that deals with the flight, behavior, and effects of projectiles, especially bullets, gravity bombs, rockets, or the like; the science or art of designing and accelerating projectiles so as to achieve a desired performance.A ballistic body is a body which is...

 trajectory to deliver the warhead over the horizon. While even short range missiles allow for a faster and less vulnerable attack, the development of long-range intercontinental ballistic missile
Intercontinental ballistic missile
An intercontinental ballistic missile is a ballistic missile with a long range typically designed for nuclear weapons delivery...

s (ICBMs) and submarine-launched ballistic missile
Submarine-launched ballistic missile
A submarine-launched ballistic missile is a ballistic missile capable of delivering a nuclear warhead that can be launched from submarines. Modern variants usually deliver multiple independently targetable reentry vehicles each of which carries a warhead and allows a single launched missile to...

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
Multiple independently targetable reentry vehicle
A multiple independently targetable reentry vehicle warhead is a collection of nuclear weapons carried on a single intercontinental ballistic missile or a submarine-launched ballistic missile . Using a MIRV warhead, a single launched missile can strike several targets, or fewer targets redundantly...

s (MIRVs), allow multiple warheads to be launched at different targets from one missile, reducing the chance of a successful missile defense
Missile defense
Missile defense is a system, weapon, or technology involved in the detection, tracking, interception and destruction of attacking missiles. Originally conceived as a defence against nuclear-armed Intercontinental ballistic missiles , its application has broadened to include shorter-ranged...

. 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 a difficult task.

Tactical weapons have involved the most variety of delivery types, including not only gravity bombs and missiles but also artillery
Artillery
Originally applied to any group of infantry primarily armed with projectile weapons, artillery has over time become limited in meaning to refer only to those engines of war that operate by projection of munitions far beyond the range of effect of personal weapons...

 shells, land mine
Land mine
A land mine is usually a weight-triggered explosive device which is intended to damage a target—either human or inanimate—by means of a blast and/or fragment impact....

s, and nuclear depth charge
Depth charge
A depth charge is an anti-submarine warfare weapon intended to destroy or cripple a target submarine by the shock of exploding near it. Most use explosives and a fuze set to go off at a preselected depth in the ocean. Depth charges can be dropped by either surface ships, patrol aircraft, or from...

s and torpedo
Torpedo
The modern torpedo is a self-propelled missile weapon with an explosive warhead, launched above or below the water surface, propelled underwater towards a target, and designed to detonate either on contact with it or in proximity to it.The term torpedo was originally employed for...

es for anti-submarine warfare
Anti-submarine warfare
Anti-submarine warfare is a branch of naval warfare that uses surface warships, aircraft, or other submarines to find, track and deter, damage or destroy enemy submarines....

. An atomic mortar
Mortar (weapon)
A mortar is an indirect fire weapon that fires explosive projectiles known as bombs at low velocities, short ranges, and high-arcing ballistic trajectories. It is typically muzzle-loading and has a barrel length less than 15 times its caliber....

 was also tested at one time by the United States. Small, two-man portable tactical weapons (somewhat misleadingly referred to as suitcase bomb
Suitcase bomb
A suitcase nuke is a tactical nuclear weapon which uses, or is portable enough that it could use, a suitcase as its delivery method. Synonyms include suitcase bomb, backpack nuke, mini-nuke, pocket nuke and snuke....

s), such as the Special Atomic Demolition Munition
Special Atomic Demolition Munition
The Special Atomic Demolition Munition was a family of man-portable nuclear weapons fielded by the US military in the 1960s, but never used in actual combat. The US Army planned to use the weapons in Europe in the event of a Soviet invasion...

, have been developed, although the difficulty of combining sufficient yield with portability limits their military utility.

Nuclear strategy




Nuclear warfare
Nuclear warfare
Nuclear warfare, or atomic warfare, is a military conflict or political strategy in which nuclear weaponry is detonated on an opponent. Compared to conventional warfare, nuclear warfare can be vastly more destructive in range and extent of damage...

 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
Deterrence theory
Deterrence theory gained increased prominence as a military strategy during the Cold War with regard to the use of nuclear weapons, and features prominently in current United States foreign policy regarding the development of nuclear technology in North Korea and Iran. Deterrence theory however was...

. 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
First strike
In nuclear strategy, a first strike is a preemptive surprise attack employing overwhelming force. First strike capability is a country's ability to defeat another nuclear power by destroying its arsenal to the point where the attacking country can survive the weakened retaliation while the opposing...

 status (the ability to completely destroy an enemy's nuclear forces before they could retaliate). During the Cold War
Cold War
The Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...

, policy and military theorists in nuclear-enabled countries worked out models of what sorts of policies could prevent one from ever being attacked by a nuclear weapon.

Different forms of nuclear weapons delivery
Nuclear weapons delivery
Nuclear weapons delivery is the technology and systems used to place a nuclear weapon at the position of detonation, on or near its target. Several methods have been developed to carry out this task....

 (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. Sometimes this has meant keeping the weapon locations hidden, such as deploying them on submarine
Submarine
A submarine is a watercraft capable of independent operation below the surface of the water. It differs from a submersible, which has more limited underwater capability...

s or rail cars whose locations are very hard for an enemy to track and other times this means protecting them by burying them in hardened bunkers.

Other components of nuclear strategies have included using missile defense
Missile defense
Missile defense is a system, weapon, or technology involved in the detection, tracking, interception and destruction of attacking missiles. Originally conceived as a defence against nuclear-armed Intercontinental ballistic missiles , its application has broadened to include shorter-ranged...

 (to destroy the missiles before they land) or implementation of civil defense
Civil defense
Civil defense, civil defence or civil protection is an effort to protect the citizens of a state from military attack. It uses the principles of emergency operations: prevention, mitigation, preparation, response, or emergency evacuation, and recovery...

 measures (using early-warning systems to evacuate citizens to safe areas before an attack).

Note that weapons which are designed to threaten large populations or to generally deter attacks are known as strategic weapons. Weapons which are designed to actually be used on a battle
Battle
Generally, a battle is a conceptual component in the hierarchy of combat in warfare between two or more armed forces, or combatants. In a battle, each combatant will seek to defeat the others, with defeat determined by the conditions of a military campaign...

field in military situations are known as tactical weapons.

There are critics of the very idea of nuclear strategy for waging nuclear war who have suggested that a nuclear war between two nuclear powers would result in mutual annihilation. From this point of view, the significance of nuclear weapons is purely to deter war because any nuclear war
Nuclear warfare
Nuclear warfare, or atomic warfare, is a military conflict or political strategy in which nuclear weaponry is detonated on an opponent. Compared to conventional warfare, nuclear warfare can be vastly more destructive in range and extent of damage...

 would immediately 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
International Court of Justice
The International Court of Justice is the primary judicial organ of the United Nations. It is based in the Peace Palace in The Hague, Netherlands...

 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.

Perhaps the most controversial idea in nuclear strategy is that nuclear proliferation
Nuclear proliferation
Nuclear proliferation is a term now used to describe the spread of nuclear weapons, fissile material, and weapons-applicable nuclear technology and information, to nations which are not recognized as "Nuclear Weapon States" by the Treaty on the Nonproliferation of Nuclear Weapons, also known as the...

 would be desirable. This view argues that, unlike conventional weapons, nuclear weapons successfully deter all-out war between states, and they are said to have done this during the Cold War
Cold War
The Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...

 between the U.S. and the Soviet Union
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....

. Political scientist Kenneth Waltz
Kenneth Waltz
Kenneth Neal Waltz is a member of the faculty at the University of California, Berkeley and Columbia University and one of the most prominent scholars of international relations alive today...

 is the most prominent advocate of this argument.

The threat of potentially suicidal terrorists possessing nuclear weapons (a form of nuclear terrorism
Nuclear terrorism
Nuclear terrorism denotes the use, or threat of the use, of nuclear weapons or radiological weapons in acts of terrorism, includingattacks against facilities where radioactive materials are present...

) complicates the decision process. The prospect of mutually assured destruction may not deter an enemy who expects to die in the confrontation. Further, if the initial act is from a rogue group instead of a sovereign nation, there is no fixed nation or fixed military targets to retaliate against. It has been argued, especially after the September 11, 2001 attacks
September 11, 2001 attacks
The September 11 attacks The September 11 attacks The September 11 attacks (also referred to as September 11, September 11th or 9/119/11 is pronounced "nine eleven". The slash is not part of the pronunciation...

, that this complication is the sign of the next age of nuclear strategy, distinct from the relative stability of the Cold War. In 1996, the United States adopted a policy of allowing the targeting of its nuclear weapons at terrorists armed with weapons of mass destruction
Weapons of mass destruction
A weapon of mass destruction is a weapon that can kill and bring significant harm to a large number of humans and/or cause great damage to man-made structures , natural structures , or the biosphere in general...

.

Governance, control, and law


Because of the immense military power they can confer, the political control of nuclear weapons has been a key issue for as long as they have existed; in most countries the use of nuclear force can only be authorized by the head of government
Head of government
Head of government is the chief officer of the executive branch of a government, often presiding over a cabinet. In a parliamentary system, the head of government is often styled prime minister, chief minister, premier, etc...

 or head of state
Head of State
A head of state is the individual that serves as the chief public representative of a monarchy, republic, federation, commonwealth or other kind of state. His or her role generally includes legitimizing the state and exercising the political powers, functions, and duties granted to the head of...

.

In the late 1940s, lack of mutual trust was preventing the United States and the Soviet Union from making ground towards international arms control agreements, but by the 1960s steps were being taken to limit both the proliferation
Nuclear proliferation
Nuclear proliferation is a term now used to describe the spread of nuclear weapons, fissile material, and weapons-applicable nuclear technology and information, to nations which are not recognized as "Nuclear Weapon States" by the Treaty on the Nonproliferation of Nuclear Weapons, also known as the...

 of nuclear weapons to other countries and the environmental effects of nuclear testing
Nuclear testing
Nuclear weapons tests are experiments carried out to determine the effectiveness, yield and explosive capability of nuclear weapons. Throughout the twentieth century, most nations that have developed nuclear weapons have tested them...

. The Partial Test Ban Treaty
Partial Test Ban Treaty
The treaty banning nuclear weapon tests in the atmosphere, in outer space and under water, often abbreviated as the Partial Test Ban Treaty , Limited Test Ban Treaty , or Nuclear Test Ban Treaty is a treaty prohibiting all test detonations of nuclear weapons...

 (1963) restricted all nuclear testing to underground nuclear testing
Underground nuclear testing
Underground nuclear testing refers to test detonations of nuclear weapons that are performed underground. When the device being tested is buried at sufficient depth, the explosion may be contained, with no release of radioactive materials to the atmosphere....

, to prevent contamination from nuclear fallout
Nuclear fallout
Fallout is the residual radioactive material propelled into the upper atmosphere following a nuclear blast, so called because it "falls out" of the sky after the explosion and shock wave have passed. It commonly refers to the radioactive dust and ash created when a nuclear weapon explodes...

, while the Nuclear Non-Proliferation Treaty
Nuclear Non-Proliferation Treaty
The Treaty on the Non-Proliferation of Nuclear Weapons, commonly known as the Non-Proliferation Treaty or NPT, is a landmark international treaty whose objective is to prevent the spread of nuclear weapons and weapons technology, to promote cooperation in the peaceful uses of nuclear energy and to...

 (1968) attempted to place restrictions on the types of activities which signatories could participate in, with the goal of allowing the transference of non-military nuclear technology
Nuclear technology
Nuclear technology is technology that involves the reactions of atomic nuclei. Among the notable nuclear technologies are nuclear power, nuclear medicine, and nuclear weapons...

 to member countries without fear of proliferation.

In 1957, the International Atomic Energy Agency
International Atomic Energy Agency
The International Atomic Energy Agency is an international organization that seeks to promote the peaceful use of nuclear energy, and to inhibit its use for any military purpose, including nuclear weapons. The IAEA was established as an autonomous organization on 29 July 1957...

 (IAEA) was established under the mandate of the United Nations
United Nations
The United Nations is an international organization whose stated aims are facilitating cooperation in international law, international security, economic development, social progress, human rights, and achievement of world peace...

 in order to encourage the development of the 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 Test Ban Treaty
Comprehensive Test Ban Treaty
The Comprehensive Nuclear-Test-Ban Treaty bans all nuclear explosions in all environments, for military or civilian purposes. It was adopted by the United Nations General Assembly on 10 September 1996 but it has not entered into force.-Status:...

 which prohibits all testing of nuclear weapons, which would impose a significant hindrance to their development by any complying country. Due to the strict entry into force criterion of the convention however, it had as of 2011 not entered into force.

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 I
START was a bilateral treaty between the United States of America and the Union of Soviet Socialist Republics on the Reduction and Limitation of Strategic Offensive Arms. The treaty was signed on 31 July 1991 and entered into force on 5 December 1994...

 (expired), INF
Intermediate-Range Nuclear Forces Treaty
The Intermediate-Range Nuclear Forces Treaty is a 1987 agreement between the United States and the Soviet Union. Signed in Washington, D.C. by U.S. President Ronald Reagan and General Secretary Mikhail Gorbachev on December 8, 1987, it was ratified by the United States Senate on May 27, 1988 and...

, START II
START II
START II was a bilateral treaty between the United States of America and Russia on the Reduction and Limitation of Strategic Offensive Arms. It was signed by United States President George H. W...

 (never ratified), SORT
SORT
The Treaty Between the United States of America and the Russian Federation on Strategic Offensive Reductions , also known as the Treaty of Moscow, was a strategic arms reduction treaty between the United States and Russia that was in force from June 2003 until February 2011 when it was superseded...

, and New START
New START
New START is a nuclear arms reduction treaty between the United States of America and the Russian Federation with the formal name of Measures for the Further Reduction and Limitation of Strategic Offensive Arms...

, 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
Nuclear-Weapon-Free Zone
A nuclear-weapons-free zone, or NWFZ is defined by the United Nations as an agreement which a group of states has freely established by treaty or convention, that bans the use, development, or deployment of nuclear weapons in a given area, that has mechanisms of verification and control to enforce...

s, areas where nuclear weapons production and deployment are prohibited, through the use of treaties. The Treaty of Tlatelolco
Treaty of Tlatelolco
The Treaty of Tlatelolco is the conventional name given to the Treaty for the Prohibition of Nuclear Weapons in Latin America and the Caribbean...

 (1967) prohibited any production or deployment of nuclear weapons in Latin America
Latin America
Latin America is a region of the Americas where Romance languages  – particularly Spanish and Portuguese, and variably French – are primarily spoken. Latin America has an area of approximately 21,069,500 km² , almost 3.9% of the Earth's surface or 14.1% of its land surface area...

 and the Caribbean
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...

, and the Treaty of Pelindaba (1964) prohibits nuclear weapons in many African countries. As recently as 2006 a Central Asian Nuclear Weapon Free Zone
Central Asian Nuclear Weapon Free Zone
The Central Asian Nuclear-Weapon-Free Zone treaty is a legally binding commitment by Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, and Uzbekistan not to manufacture, acquire, test, or possess nuclear weapons...

 was established amongst the former Soviet republics of Central Asia prohibiting nuclear weapons.

In the middle of 1996, the International Court of Justice
International Court of Justice
The International Court of Justice is the primary judicial organ of the United Nations. It is based in the Peace Palace in The Hague, Netherlands...

, 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
International law
Public international law concerns the structure and conduct of sovereign states; analogous entities, such as the Holy See; and intergovernmental organizations. To a lesser degree, international law also may affect multinational corporations and individuals, an impact increasingly evolving beyond...

, including the Geneva Conventions
Geneva Conventions
The Geneva Conventions comprise four treaties, and three additional protocols, that establish the standards of international law for the humanitarian treatment of the victims of war...

, the Hague Conventions
Hague Conventions (1899 and 1907)
The Hague Conventions were two international treaties negotiated at international peace conferences at The Hague in the Netherlands: The First Hague Conference in 1899 and the Second Hague Conference in 1907...

, the UN Charter, and the Universal Declaration of Human Rights
Universal Declaration of Human Rights
The Universal Declaration of Human Rights is a declaration adopted by the United Nations General Assembly . The Declaration arose directly from the experience of the Second World War and represents the first global expression of rights to which all human beings are inherently entitled...

. In view of the unique, destructive characteristics of nuclear weapons, the International Committee of the Red Cross
International Committee of the Red Cross
The International Committee of the Red Cross is a private humanitarian institution based in Geneva, Switzerland. States parties to the four Geneva Conventions of 1949 and their Additional Protocols of 1977 and 2005, have given the ICRC a mandate to protect the victims of international and...

 calls on States to ensure that these weapons are never used, irrespective of whether they consider them to be 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
Casus belli
is a Latin expression meaning the justification for acts of war. means "incident", "rupture" or indeed "case", while means bellic...

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
Operation Opera
Operation Babylon was a surprise Israeli air strike carried out on June 7, 1981, that destroyed a nuclear reactor under construction 17 kilometers southeast of Baghdad, Iraq....

 being constructed in Osirak, Iraq
Iraq
Iraq ; officially the Republic of Iraq is a country in Western Asia spanning most of the northwestern end of the Zagros mountain range, the eastern part of the Syrian Desert and the northern part of the Arabian Desert....

, in what it called an attempt to halt Iraq's previous nuclear arms ambitions; in 2007, Israel bombed another reactor
Operation Orchard
Operation Orchard was an Israeli airstrike on a nuclear reactor in the Deir ez-Zor region of Syria carried out just after midnight on September 6, 2007. The White House and Central Intelligence Agency later confirmed that American intelligence had also indicated the site was a nuclear facility...

 being constructed in Syria
Syria
Syria , officially the Syrian Arab Republic , is a country in Western Asia, bordering Lebanon and the Mediterranean Sea to the West, Turkey to the north, Iraq to the east, Jordan to the south, and Israel to the southwest....

.

Disarmament




Nuclear disarmament
Nuclear disarmament
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 completely eliminated....

 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 completely eliminated.

Beginning with the 1963 Partial Test Ban Treaty
Partial Test Ban Treaty
The treaty banning nuclear weapon tests in the atmosphere, in outer space and under water, often abbreviated as the Partial Test Ban Treaty , Limited Test Ban Treaty , or Nuclear Test Ban Treaty is a treaty prohibiting all test detonations of nuclear weapons...

 and continuing through the 1996 Comprehensive Test Ban Treaty
Comprehensive Test Ban Treaty
The Comprehensive Nuclear-Test-Ban Treaty bans all nuclear explosions in all environments, for military or civilian purposes. It was adopted by the United Nations General Assembly on 10 September 1996 but it has not entered into force.-Status:...

, there have been many treaties to limit or reduce nuclear weapons testing and stockpiles. The 1968 Nuclear Non-Proliferation Treaty
Nuclear Non-Proliferation Treaty
The Treaty on the Non-Proliferation of Nuclear Weapons, commonly known as the Non-Proliferation Treaty or NPT, is a landmark international treaty whose objective is to prevent the spread of nuclear weapons and weapons technology, to promote cooperation in the peaceful uses of nuclear energy and to...

 has as one of its explicit conditions that all signatories must "pursue negotiations in good faith" towards the long-term goal of "complete disarmament". However, no nuclear state has treated that aspect of the agreement as having binding force.

Only one country—South Africa—has ever fully renounced nuclear weapons they had independently developed. A number of former Soviet republics—Belarus
Belarus
Belarus , officially the Republic of Belarus, is a landlocked country in Eastern Europe, bordered clockwise by Russia to the northeast, Ukraine to the south, Poland to the west, and Lithuania and Latvia to the northwest. Its capital is Minsk; other major cities include Brest, Grodno , Gomel ,...

, Kazakhstan
Kazakhstan
Kazakhstan , officially the Republic of Kazakhstan, is a transcontinental country in Central Asia and Eastern Europe. Ranked as the ninth largest country in the world, it is also the world's largest landlocked country; its territory of is greater than Western Europe...

, and Ukraine
Ukraine
Ukraine is a country in Eastern Europe. It has an area of 603,628 km², making it the second largest contiguous country on the European continent, after Russia...

—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
Nuclear warfare
Nuclear warfare, or atomic warfare, is a military conflict or political strategy in which nuclear weaponry is detonated on an opponent. Compared to conventional warfare, nuclear warfare can be vastly more destructive in range and extent of damage...

 occurring, especially accidentally. Critics of nuclear disarmament say that it would undermine deterrence
Deterrence theory
Deterrence theory gained increased prominence as a military strategy during the Cold War with regard to the use of nuclear weapons, and features prominently in current United States foreign policy regarding the development of nuclear technology in North Korea and Iran. Deterrence theory however was...

 and could lead to increased global instability. Various American government officials, who were in office during the Cold War
Cold War
The Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...

 period, have recently been advocating the elimination of nuclear weapons. These officials include Henry Kissinger
Henry Kissinger
Heinz Alfred "Henry" Kissinger is a German-born American academic, political scientist, diplomat, and businessman. He is a recipient of the Nobel Peace Prize. He served as National Security Advisor and later concurrently as Secretary of State in the administrations of Presidents Richard Nixon and...

, George Shultz, Sam Nunn
Sam Nunn
Samuel Augustus Nunn, Jr. is an American lawyer and politician. Currently the co-chairman and Chief Executive Officer of the Nuclear Threat Initiative , a charitable organization working to reduce the global threats from nuclear, biological and chemical weapons, Nunn served for 24 years as a...

, and William Perry
William Perry
William James Perry is an American businessman and engineer who was the United States Secretary of Defense from February 3, 1994, to January 23, 1997, under President Bill Clinton...

. In January 2010, Lawrence M. Krauss
Lawrence M. Krauss
Lawrence Maxwell Krauss is an American theoretical physicist who is professor of physics, Foundation Professor of the School of Earth and Space Exploration, and director of the Origins Project at the Arizona State University. He is the author of several bestselling books, including The Physics of...

 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 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
Global Zero (campaign)
Global Zero is an international initiative launched in December 2008 to promote the elimination of nuclear weapons. It proposes a phased withdrawal and verification for the destruction of all devices held by official and unofficial members of the nuclear club...

 movement, and the goal of a "world without nuclear weapons" was advocated by United States President Barack Obama
Barack Obama
Barack Hussein Obama II is the 44th and current President of the United States. He is the first African American to hold the office. Obama previously served as a United States Senator from Illinois, from January 2005 until he resigned following his victory in the 2008 presidential election.Born in...

 in an April 2009 speech in Prague
Prague
Prague is the capital and largest city of the Czech Republic. Situated in the north-west of the country on the Vltava river, the city is home to about 1.3 million people, while its metropolitan area is estimated to have a population of over 2.3 million...

. A CNN
CNN
Cable News Network is a U.S. cable news channel founded in 1980 by Ted Turner. Upon its launch, CNN was the first channel to provide 24-hour television news coverage, and the first all-news television channel in the United States...

 poll from April 2010 indicated that the American public was nearly evenly split on the issue.

Controversy


Even before the first nuclear weapons had been developed, scientists involved with the Manhattan Project
Manhattan Project
The Manhattan Project was a research and development program, led by the United States with participation from the United Kingdom and Canada, that produced the first atomic bomb during World War II. From 1942 to 1946, the project was under the direction of Major General Leslie Groves of the US Army...

 were divided over the use of the weapon. The role of the two atomic bombings of the country in Japan's surrender
Surrender of Japan
The surrender of Japan in 1945 brought hostilities of World War II to a close. By the end of July 1945, the Imperial Japanese Navy was incapable of conducting operations and an Allied invasion of Japan was imminent...

 and the U.S.'s ethical
Ethics
Ethics, also known as moral philosophy, is a branch of philosophy that addresses questions about morality—that is, concepts such as good and evil, right and wrong, virtue and vice, justice and crime, etc.Major branches of ethics include:...

 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.

Radioactive fallout from nuclear weapons testing was first drawn to public attention in 1954 when the Castle Bravo
Castle Bravo
Castle Bravo was the code name given to the first U.S. test of a dry fuel thermonuclear hydrogen bomb device, detonated on March 1, 1954 at Bikini Atoll, Marshall Islands, as the first test of Operation Castle. Castle Bravo was the most powerful nuclear device ever detonated by the United States ,...

 hydrogen bomb test at the Pacific Proving Grounds
Pacific Proving Grounds
The Pacific Proving Grounds was the name used to describe a number of sites in the Marshall Islands and a few other sites in the Pacific Ocean, used by the United States to conduct nuclear testing at various times between 1946 and 1962...

 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
Tuna
Tuna is a salt water fish from the family Scombridae, mostly in the genus Thunnus. Tuna are fast swimmers, and some species are capable of speeds of . Unlike most fish, which have white flesh, the muscle tissue of tuna ranges from pink to dark red. The red coloration derives from myoglobin, an...

 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
Nuclear fallout
Fallout is the residual radioactive material propelled into the upper atmosphere following a nuclear blast, so called because it "falls out" of the sky after the explosion and shock wave have passed. It commonly refers to the radioactive dust and ash created when a nuclear weapon explodes...

 and atmospheric nuclear testing
Nuclear testing
Nuclear weapons tests are experiments carried out to determine the effectiveness, yield and explosive capability of nuclear weapons. Throughout the twentieth century, most nations that have developed nuclear weapons have tested them...

, and "provided a decisive impetus for the emergence of the anti-nuclear weapons movement in many countries".

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".

In the United Kingdom, the first Aldermaston March
Aldermaston Marches
The Aldermaston marches were protest demonstrations organised by the British anti-war Campaign for Nuclear Disarmament in the 1950s and 1960s. They took place on Easter weekend between the Atomic Weapons Research Establishment at Aldermaston in Berkshire, England, and London, over a distance of...

 organised by the Campaign for Nuclear Disarmament
Campaign for Nuclear Disarmament
The Campaign for Nuclear Disarmament is an anti-nuclear organisation that advocates unilateral nuclear disarmament by the United Kingdom, international nuclear disarmament and tighter international arms regulation through agreements such as the Nuclear Non-Proliferation Treaty...

 took place at Easter
Easter
Easter is the central feast in the Christian liturgical year. According to the Canonical gospels, Jesus rose from the dead on the third day after his crucifixion. His resurrection is celebrated on Easter Day or Easter Sunday...

 1958, when several thousand people marched for four days from Trafalgar Square
Trafalgar Square
Trafalgar Square is a public space and tourist attraction in central London, England, United Kingdom. At its centre is Nelson's Column, which is guarded by four lion statues at its base. There are a number of statues and sculptures in the square, with one plinth displaying changing pieces of...

, London, to the Atomic Weapons Research Establishment
Atomic Weapons Establishment
The Atomic Weapons Establishment is responsible for the design, manufacture and support of warheads for the United Kingdom's nuclear deterrent. AWE plc is responsible for the day-to-day operations of AWE...

 close to Aldermaston
Aldermaston
Aldermaston is a rural village, civil parish and electoral ward in Berkshire, South-East England. In the 2001 United Kingdom Census, the parish had a population of 927. The village is on the southern edge of the River Kennet flood plain, near the Hampshire county boundary...

 in Berkshire
Berkshire
Berkshire is a historic county in the South of England. It is also often referred to as the Royal County of Berkshire because of the presence of the royal residence of Windsor Castle in the county; this usage, which dates to the 19th century at least, was recognised by the Queen in 1957, and...

, 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 Atomic Scientists was the start of a successful campaign to stop the Atomic Energy Commission
United States Atomic Energy Commission
The United States Atomic Energy Commission was an agency of the United States government established after World War II by Congress to foster and control the peace time development of atomic science and technology. President Harry S...

 dumping radioactive waste
Radioactive waste
Radioactive wastes are wastes that contain radioactive material. Radioactive wastes are usually by-products of nuclear power generation and other applications of nuclear fission or nuclear technology, such as research and medicine...

 in the sea 19 kilometres from Boston
Boston
Boston is the capital of and largest city in Massachusetts, and is one of the oldest cities in the United States. The largest city in New England, Boston is regarded as the unofficial "Capital of New England" for its economic and cultural impact on the entire New England region. The city proper had...

. In 1962, Linus Pauling
Linus Pauling
Linus Carl Pauling was an American chemist, biochemist, peace activist, author, and educator. He was one of the most influential chemists in history and ranks among the most important scientists of the 20th century...

 won the Nobel Peace Prize
Nobel Peace Prize
The Nobel Peace Prize is one of the five Nobel Prizes bequeathed by the Swedish industrialist and inventor Alfred Nobel.-Background:According to Nobel's will, the Peace Prize shall be awarded to the person who...

 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
Partial Test Ban Treaty
The treaty banning nuclear weapon tests in the atmosphere, in outer space and under water, often abbreviated as the Partial Test Ban Treaty , Limited Test Ban Treaty , or Nuclear Test Ban Treaty is a treaty prohibiting all test detonations of nuclear weapons...

 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.

Between 1940 and 1996, the U.S. spent at least $ in present day terms on nuclear weapons development. Over half was spent on building delivery mechanisms for the weapon. $ in present day terms was spent on nuclear waste
Radioactive waste
Radioactive wastes are wastes that contain radioactive material. Radioactive wastes are usually by-products of nuclear power generation and other applications of nuclear fission or nuclear technology, such as research and medicine...

 management and environmental remediation.

Non-weapons uses




Apart from their use as weapons, nuclear explosive
Nuclear explosive
A nuclear explosive is an explosive device that derives its energy from nuclear reactions. Almost all nuclear explosive devices that have been designed and produced are nuclear weapons intended for warfare....

s have been tested and used for various non-military uses
Peaceful nuclear explosions
Peaceful nuclear explosions are nuclear explosions conducted for non-military purposes, such as activities related to economic development including the creation of canals...

, and proposed, but not used for large-scale earth moving. When long term health and clean-up costs were included, there was no economic advantage over conventional explosives.

Synthetic elements, such as einsteinium
Einsteinium
Einsteinium is a synthetic element with the symbol Es and atomic number 99. It is the seventh transuranic element, and an actinide.Einsteinium was discovered in the debris of the first hydrogen bomb explosion in 1952, and named after Albert Einstein...

 and fermium
Fermium
Fermium is a synthetic element with the symbol Fm. It is the 100th element in the periodic table and a member of the actinide series. It is the heaviest element that can be formed by neutron bombardment of lighter elements, and hence the last element that can be prepared in macroscopic quantities,...

, created by neutron bombardment of uranium and plutonium during thermonuclear explosions, were discovered in the aftermath of the first thermonuclear bomb test. In 2008 the worldwide presence of new isotopes from atmospheric testing beginning in the 1950s was developed into a reliable way of detecting art forgeries, as all paintings created after that period may contain traces of cesium-137 and strontium-90
Strontium-90
Strontium-90 is a radioactive isotope of strontium, with a half-life of 28.8 years.-Radioactivity:Natural strontium is nonradioactive and nontoxic, but 90Sr is a radioactivity hazard...

, isotopes that did not exist in nature before 1945.

Nuclear explosives have also been seriously studied as potential propulsion mechanisms for space travel (see Project Orion
Project Orion (nuclear propulsion)
Project Orion was a study of a spacecraft intended to be directly propelled by a series of explosions of atomic bombs behind the craft...

) and for asteroid deflection.

History

  • History of nuclear weapons
    History of nuclear weapons
    The history of nuclear weapons chronicles the development of nuclear weapons. Nuclear weapons possess enormous destructive potential derived from nuclear fission or nuclear fusion reactions...

    • German nuclear energy project
      German nuclear energy project
      The German nuclear energy project, , was an attempted clandestine scientific effort led by Germany to develop and produce the atomic weapons during the events involving the World War II...

    • Japanese atomic program
      Japanese atomic program
      The Japanese program to develop nuclear weapons was conducted during World War II. Like the German nuclear weapons program, it suffered from an array of problems, and was ultimately unable to progress beyond the laboratory stage before the atomic bombings of Hiroshima and Nagasaki and the Japanese...

    • Manhattan Project
      Manhattan Project
      The Manhattan Project was a research and development program, led by the United States with participation from the United Kingdom and Canada, that produced the first atomic bomb during World War II. From 1942 to 1946, the project was under the direction of Major General Leslie Groves of the US Army...

    • Soviet atomic bomb project
      Soviet atomic bomb project
      The Soviet project to develop an atomic bomb , was a clandestine research and development program began during and post-World War II, in the wake of the Soviet Union's discovery of the United States' nuclear project...

  • Los Alamos National Laboratory
    Los Alamos National Laboratory
    Los Alamos National Laboratory is a United States Department of Energy national laboratory, managed and operated by Los Alamos National Security , located in Los Alamos, New Mexico...

  • Lawrence Livermore National Laboratory
    Lawrence Livermore National Laboratory
    The Lawrence Livermore National Laboratory , just outside Livermore, California, is a Federally Funded Research and Development Center founded by the University of California in 1952...

  • Lists of nuclear disasters and radioactive incidents
  • Nuclear and radiation accidents
    Nuclear and radiation accidents
    A nuclear and radiation accident is defined by the International Atomic Energy Agency as "an event that has led to significant consequences to people, the environment or the facility...

    , including nuclear weapons accidents
  • Nuclear testing
    Nuclear testing
    Nuclear weapons tests are experiments carried out to determine the effectiveness, yield and explosive capability of nuclear weapons. Throughout the twentieth century, most nations that have developed nuclear weapons have tested them...

    • Nevada Test Site
      Nevada Test Site
      The Nevada National Security Site , previously the Nevada Test Site , is a United States Department of Energy reservation located in southeastern Nye County, Nevada, about northwest of the city of Las Vegas...

    • Project Gnome
      Project GNOME
      Project Gnome was the first nuclear test of the Plowshare program and was the first continental nuclear weapon test since Trinity to be conducted outside of the Nevada Test Site...

  • Military strategy
    Military strategy
    Military strategy is a set of ideas implemented by military organizations to pursue desired strategic goals. Derived from the Greek strategos, strategy when it appeared in use during the 18th century, was seen in its narrow sense as the "art of the general", 'the art of arrangement' of troops...

    • Civil Defense
      Civil defense
      Civil defense, civil defence or civil protection is an effort to protect the citizens of a state from military attack. It uses the principles of emergency operations: prevention, mitigation, preparation, response, or emergency evacuation, and recovery...

    • Fractional Orbital Bombardment System
      Fractional Orbital Bombardment System
      The Fractional Orbital Bombardment System was a Soviet ICBM program in the 1960s that after launch would go into a low Earth orbit and would then de-orbit for an attack. It had no range limit and the orbital flight path would not reveal the target location...

    • Mutual Assured Destruction
      Mutual assured destruction
      Mutual Assured Destruction, or mutually assured destruction , is a doctrine of military strategy and national security policy in which a full-scale use of high-yield weapons of mass destruction by two opposing sides would effectively result in the complete, utter and irrevocable annihilation of...

  • Weapon of mass destruction
    • Nuclear strategy
      Nuclear strategy
      Nuclear strategy involves the development of doctrines and strategies for the production and use of nuclear weapons.As a sub-branch of military strategy, nuclear strategy attempts to match nuclear weapons as means to political ends...

    • Nuclear warfare
      Nuclear warfare
      Nuclear warfare, or atomic warfare, is a military conflict or political strategy in which nuclear weaponry is detonated on an opponent. Compared to conventional warfare, nuclear warfare can be vastly more destructive in range and extent of damage...


More technical details

  • Effects of nuclear explosions
    Effects of nuclear explosions
    The energy released from a nuclear weapon detonated in the troposphere can be divided into four basic categories:*Blast—40-50% of total energy*Thermal radiation—30-50% of total energy...

  • Intercontinental ballistic missile
    Intercontinental ballistic missile
    An intercontinental ballistic missile is a ballistic missile with a long range typically designed for nuclear weapons delivery...

  • Neutron bomb
    Neutron bomb
    A neutron bomb or enhanced radiation weapon or weapon of reinforced radiation is a type of thermonuclear weapon designed specifically to release a large portion of its energy as energetic neutron radiation rather than explosive energy...

  • Nuclear bombs and health
  • Nuclear weapon design
    Nuclear weapon design
    Nuclear weapon designs are physical, chemical, and engineering arrangements that cause the physics package of a nuclear weapon to detonate. There are three basic design types...

  • Nuclear weapon yield
    Nuclear weapon yield
    The explosive yield of a nuclear weapon is the amount of energy discharged when a nuclear weapon is detonated, expressed usually in the equivalent mass of trinitrotoluene , either in kilotons or megatons , but sometimes also in terajoules...


Proliferation and politics

  • Agency for the Prohibition of Nuclear Weapons in Latin America and the Caribbean
    OPANAL
    The OPANAL is an international organization which promotes nuclear disarmament...

  • Comprehensive Test Ban Treaty
    Comprehensive Test Ban Treaty
    The Comprehensive Nuclear-Test-Ban Treaty bans all nuclear explosions in all environments, for military or civilian purposes. It was adopted by the United Nations General Assembly on 10 September 1996 but it has not entered into force.-Status:...

  • International Court of Justice advisory opinion on legality of nuclear weapons
  • List of states with nuclear weapons
  • List of nuclear weapons
  • Nth Country Experiment
    Nth Country Experiment
    The Nth Country Experiment was an experiment conducted by Lawrence Livermore National Laboratory starting in May 1964 which sought to assess the risk of nuclear proliferation...

  • Nuclear disarmament
    Nuclear disarmament
    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 completely eliminated....

  • Nuclear explosive
    Nuclear explosive
    A nuclear explosive is an explosive device that derives its energy from nuclear reactions. Almost all nuclear explosive devices that have been designed and produced are nuclear weapons intended for warfare....

  • Nuclear Non-Proliferation Treaty
    Nuclear Non-Proliferation Treaty
    The Treaty on the Non-Proliferation of Nuclear Weapons, commonly known as the Non-Proliferation Treaty or NPT, is a landmark international treaty whose objective is to prevent the spread of nuclear weapons and weapons technology, to promote cooperation in the peaceful uses of nuclear energy and to...

  • Nuclear peace
    Nuclear peace
    Nuclear peace is a theory of International Relations which argues that under some circumstances nuclear weapons can induce stability and decrease the chances of crisis escalation. In particular, nuclear weapons are said to have induced stability during the Cold War, when both the U.S. and the...

  • Nuclear proliferation
    Nuclear proliferation
    Nuclear proliferation is a term now used to describe the spread of nuclear weapons, fissile material, and weapons-applicable nuclear technology and information, to nations which are not recognized as "Nuclear Weapon States" by the Treaty on the Nonproliferation of Nuclear Weapons, also known as the...

  • Nuclear weapons and the United Kingdom
    Nuclear weapons and the United Kingdom
    The United Kingdom was the third country to test an independently developed nuclear weapon, in October 1952. It is one of the five "Nuclear Weapons States" under the Nuclear Non-Proliferation Treaty, which the UK ratified in 1968...

  • The Letters of last resort
    Letters of last resort
    The letters of last resort are four identically-worded, hand written letters written by the Prime Minister of the United Kingdom to the four captains of the four British ballistic missile submarines...

     (United Kingdom)
  • Nuclear weapons and Russia
  • Nuclear weapons and the United States
    Nuclear weapons and the United States
    The United States was the first country to develop nuclear weapons, and is the only country to have used them in warfare, with the separate bombings of Hiroshima and Nagasaki in World War II. Before and during the Cold War it conducted over a thousand nuclear tests and developed many long-range...

  • Paranuclear
    Paranuclear
    Paranuclear countries are those that have the ability to build nuclear weapons within months. The more common term for this is "nuclear capable" — the nation chooses not to develop nuclear weapons, but has the infrastructure to do so in a short period of time. Germany and Japan are usually...

  • Strategic Arms Limitation Talks
    Strategic Arms Limitation Talks
    The Strategic Arms Limitation Treaty refers to two rounds of bilateral talks and corresponding international treaties involving the United States and the Soviet Union—the Cold War superpowers—on the issue of armament control. There were two rounds of talks and agreements: SALT I and SALT...

  • Three Non-Nuclear Principles
    Three Non-Nuclear Principles
    Japan's are a parliamentary resolution that have guided Japanese nuclear policy since their inception in the late 1960s, and reflect general public sentiment and national policy since the end of World War II. The tenets state that Japan shall neither possess nor manufacture nuclear weapons, nor...

    , of Japan

External links



General


Historical