Nuclear weapons testing

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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 developed nuclear weapons tested them. Testing nuclear weapons can yield information about how the weapons work, as well as how the weapons behave under various conditions and how personnel, structures, and equipment behave when subjected to nuclear explosions. Nuclear testing has often been used as an indicator of scientific and military strength, and many tests have been overtly political in their intention; most nuclear weapons states publicly declared their nuclear status by means of a nuclear test.

Nuclear weapon Explosive device that derives its destructive force from nuclear reactions

A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or from a combination of fission and fusion reactions. 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 20,000 tons of TNT (84 TJ). The first thermonuclear ("hydrogen") bomb test released energy approximately equal to 10 million tons of TNT (42 PJ). A thermonuclear weapon weighing little more than 2,400 pounds (1,100 kg) can release energy equal to more than 1.2 million tons of TNT (5.0 PJ). 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.

Contents

The first nuclear device was detonated as a test by the United States at the Trinity site on July 16, 1945, with a yield approximately equivalent to 20 kilotons of TNT. The first thermonuclear weapon technology test of an engineered device, codenamed "Ivy Mike", was tested at the Enewetak Atoll in the Marshall Islands on November 1, 1952 (local date), also by the United States. The largest nuclear weapon ever tested was the "Tsar Bomba" of the Soviet Union at Novaya Zemlya on October 30, 1961, with the largest yield ever seen, an estimated 50–58 megatons.

TNT equivalent unit of measurement

TNT equivalent is a convention for expressing energy, typically used to describe the energy released in an explosion. The "ton of TNT" is a unit of energy defined by that convention to be 4.184 gigajoules, which is the approximate energy released in the detonation of a metric ton of TNT. In other words, for each gram of TNT exploded, 4,184 joules of energy are released.

Thermonuclear weapon 2-stage nuclear fission weapon

A thermonuclear weapon, or fusion weapon, is a second-generation nuclear weapon design which affords vastly greater destructive power than first-generation atomic bombs. Modern fusion weapons consist essentially of two main components: a nuclear fission primary stage and a separate nuclear fusion secondary stage containing thermonuclear fuel: the heavy hydrogen isotopes deuterium and tritium, or in modern weapons lithium deuteride. For this reason, thermonuclear weapons are often colloquially called hydrogen bombs or H-bombs.

Ivy Mike Nuclear test

Ivy Mike was the codename given to the first test of a full-scale thermonuclear device, in which part of the explosive yield comes from nuclear fusion. It was detonated on November 1, 1952 by the United States on the island of Elugelab in Enewetak Atoll, in the Pacific Ocean, as part of Operation Ivy. It was the first full test of the Teller–Ulam design, a staged fusion device.

In 1963, three (UK, US, Soviet Union) of the four nuclear states and many non-nuclear states signed the Limited Test Ban Treaty, pledging to refrain from testing nuclear weapons in the atmosphere, underwater, or in outer space. The treaty permitted underground nuclear testing. France continued atmospheric testing until 1974, and China continued until 1980. Neither has signed the treaty. [1]

Outer space Void between celestial bodies

Outer space, or just space, is the expanse that exists beyond the Earth and between celestial bodies. Outer space is not completely empty—it is a hard vacuum containing a low density of particles, predominantly a plasma of hydrogen and helium, as well as electromagnetic radiation, magnetic fields, neutrinos, dust, and cosmic rays. The baseline temperature, as set by the background radiation from the Big Bang, is 2.7 kelvins. The plasma between galaxies accounts for about half of the baryonic (ordinary) matter in the universe; it has a number density of less than one hydrogen atom per cubic metre and a temperature of millions of kelvins; local concentrations of this plasma have condensed into stars and galaxies. Studies indicate that 90% of the mass in most galaxies is in an unknown form, called dark matter, which interacts with other matter through gravitational but not electromagnetic forces. Observations suggest that the majority of the mass-energy in the observable universe is a poorly understood vacuum energy of space, which astronomers label dark energy. Intergalactic space takes up most of the volume of the universe, but even galaxies and star systems consist almost entirely of empty space.

Underground tests in the United States continued until 1992 (its last nuclear test), the Soviet Union until 1990, the United Kingdom until 1991, and both China and France until 1996. In signing the Comprehensive Nuclear-Test-Ban Treaty in 1996, these states have pledged to discontinue all nuclear testing; the treaty has not yet entered into force because of failure to be ratified by eight countries. Non-signatories India and Pakistan last tested nuclear weapons in 1998. North Korea conducted nuclear tests in 2006, 2009, 2013, 2016, and 2017. The most recent confirmed nuclear test occurred in September 2017 in North Korea.

Comprehensive Nuclear-Test-Ban Treaty

The Comprehensive Nuclear-Test-Ban Treaty (CTBT) is a multilateral treaty that bans all nuclear explosions, for both civilian and military purposes, in all environments. It was adopted by the United Nations General Assembly on 10 September 1996, but has not entered into force, as eight specific states have not ratified the treaty.

India and weapons of mass destruction

The Republic of India has developed and possesses weapons of mass destruction in the form of nuclear weapons. Though India has not made any official statements about the size of its nuclear arsenal, recent estimates suggest that India has 110 nuclear weapons — consistent with earlier estimates that it had produced enough weapons-grade plutonium for up to 75–110 nuclear weapons. In 1999, India was estimated to have 800 kg of separated reactor-grade plutonium, with a total amount of 8,300 kg of civilian plutonium, enough for approximately 1,000 nuclear weapons.

Pakistan and weapons of mass destruction

Pakistan is one of nine states to possess nuclear weapons. Pakistan began development of nuclear weapons in January 1972 under Prime Minister Zulfikar Ali Bhutto, who delegated the program to the Chairman of the Pakistan Atomic Energy Commission (PAEC) Munir Ahmad Khan with a commitment to having the bomb ready by the end of 1976. Since PAEC, consisting of over twenty laboratories and projects under nuclear engineer Munir Ahmad Khan, was falling behind schedule and having considerable difficulty producing fissile material, Abdul Qadeer Khan was brought from Europe by Bhutto at the end of 1974. As pointed out by Houston Wood, Professor of Mechanical & Aerospace Engineering, University of Virginia, Charlottesville, in his article on gas centrifuges, "The most difficult step in building a nuclear weapon is the production of fissile material"; as such, this work in producing fissile material as head of the Kahuta Project was pivotal to Pakistan developing the capability to detonate a nuclear bomb by the end of 1984.

Types

Four major types of nuclear testing: 1. atmospheric, 2. underground, 3. exoatmospheric, and 4. underwater Types of nuclear testing.svg
Four major types of nuclear testing: 1. atmospheric, 2. underground, 3. exoatmospheric, and 4. underwater

Nuclear weapons tests have historically been divided into four categories reflecting the medium or location of the test.

Atmosphere of Earth Layer of gases surrounding the planet Earth

The atmosphere of Earth is the layer of gases, commonly known as air, that surrounds the planet Earth and is retained by Earth's gravity. The atmosphere of Earth protects life on Earth by creating pressure allowing for liquid water to exist on the Earth's surface, absorbing ultraviolet solar radiation, warming the surface through heat retention, and reducing temperature extremes between day and night.

Mushroom cloud cloud

A mushroom cloud is a distinctive pyrocumulus mushroom-shaped cloud of debris/smoke and usually condensed water vapor resulting from a large explosion. The effect is most commonly associated with a nuclear explosion, but any sufficiently energetic detonation or deflagration will produce the same effect. They can be caused by powerful conventional weapons, like thermobaric weapons, including the ATBIP and GBU-43/B Massive Ordnance Air Blast. Some volcanic eruptions and impact events can produce natural mushroom clouds.

Nuclear fallout residual radioactive material following a nuclear blast

Nuclear fallout, or 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 the shock wave have passed. It commonly refers to the radioactive dust and ash created when a nuclear weapon explodes. The amount and spread of fallout is a product of the size of the weapon and the altitude at which it is detonated. Fallout may get entrained with the products of a pyrocumulus cloud and fall as black rain.

Salvo tests

Another way to classify nuclear tests are by the number of explosions that constitute the test. The treaty definition of a salvo test is:

In conformity with treaties between the United States and the Soviet Union, a salvo is defined, for multiple explosions for peaceful purposes, as two or more separate explosions where a period of time between successive individual explosions does not exceed 5 seconds and where the burial points of all explosive devices can be connected by segments of straight lines, each of them connecting two burial points, and the total length does not exceed 40 kilometers. For nuclear weapon tests, a salvo is defined as two or more underground nuclear explosions conducted at a test site within an area delineated by a circle having a diameter of two kilometers and conducted within a total period of time of 0.1 second. [3]

The USSR has exploded up to eight devices in a single salvo test; Pakistan's second and last official test exploded four different devices. Almost all lists in the literature are lists of tests; in the lists in Wikipedia (for example, Operation Cresset has separate items for Cremino and Caerphilly, which together constitute a single test), the lists are of explosions.

Purpose

Separately from these designations, nuclear tests are also often categorized by the purpose of the test itself.

Aside from these technical considerations, tests have been conducted for political and training purposes, and can often serve multiple purposes.

Alternatives to full-scale testing

Sub-critical experiment at the Nevada National Security Site NTS - LLNL subcritical experiment.jpg
Sub-critical experiment at the Nevada National Security Site

Hydronuclear tests study nuclear materials under the conditions of explosive shock compression. They can create sub-critical conditions, or supercritical conditions with yields ranging from negligible all the way up to a substantial fraction of full weapon yield. [4]

Critical mass experiments determine the quantity of fissile material required for criticality with a variety of fissile material compositions, densities, shapes, and reflectors. They can be sub-critical or super-critical, in which case significant radiation fluxes can be produced. This type of test has resulted in several criticality accidents.

Sub-critical (or cold) tests are any type of tests involving nuclear materials and possibly high-explosives (like those mentioned above) that purposely result in no yield. The name refers to the lack of creation of a critical mass of fissile material. They are the only type of tests allowed under the interpretation of the Comprehensive Nuclear-Test-Ban Treaty tacitly agreed to by the major atomic powers. [5] [6] Sub-critical tests continue to be performed by the United States, Russia, and the People's Republic of China, at least. [7] [8]

Subcritical test executed by the United States include: [9] [10] [11]

Subcritical Tests
NameDate Time (UT [lower-alpha 1] )LocationElevation + HeightNotes
A series of 50 testsJanuary 1, 1960 Los Alamos National Lab Test Area 49 35°49′22″N106°18′08″W / 35.82289°N 106.30216°W / 35.82289; -106.30216 2,183 metres (7,162 ft) - 20 metres (66 ft)Series of 50 tests during US/USSR joint nuclear test ban. [12]
Odyssey NTS Area U1a 37°00′41″N116°03′35″W / 37.01139°N 116.05983°W / 37.01139; -116.05983 1,222 metres (4,009 ft) - 190 metres (620 ft)
TrumpetNTS Area U1a-102D 37°00′40″N116°03′31″W / 37.01099°N 116.05848°W / 37.01099; -116.05848 1,222 metres (4,009 ft) - 190 metres (620 ft)
KismetMarch 1, 1995NTS Area U1a 37°00′41″N116°03′35″W / 37.01139°N 116.05983°W / 37.01139; -116.05983 1,222 metres (4,009 ft) - 293 metres (961 ft)Kismet was a proof of concept for modern hydronuclear tests; it did not contain any SNM (Special Nuclear Material - Plutonium or Uranium).
ReboundJuly 2, 1997 10:--:--NTS Area U1a 37°00′41″N116°03′35″W / 37.01139°N 116.05983°W / 37.01139; -116.05983 1,222 metres (4,009 ft) - 293 metres (961 ft)Provided information on the behavior of new plutonium alloys compressed by high pressure shock waves; same as Stagecoach but for the age of the alloys.
HologSeptember 18, 1997NTS Area U1a.101A 37°00′37″N116°03′32″W / 37.01036°N 116.05888°W / 37.01036; -116.05888 1,222 metres (4,009 ft) - 290 metres (950 ft)Holog and Clarinet may have switched locations.
StagecoachMarch 25, 1998NTS Area U1a 37°00′41″N116°03′35″W / 37.01139°N 116.05983°W / 37.01139; -116.05983 1,222 metres (4,009 ft) - 290 metres (950 ft)Provided information on the behavior of aged (up to 40 years) plutonium alloys compressed by high pressure shock waves.
BagpipeSeptember 26, 1998NTS Area U1a.101B 37°00′37″N116°03′32″W / 37.01021°N 116.05886°W / 37.01021; -116.05886 1,222 metres (4,009 ft) - 290 metres (950 ft)
CimarronDecember 11, 1998NTS Area U1a 37°00′41″N116°03′35″W / 37.01139°N 116.05983°W / 37.01139; -116.05983 1,222 metres (4,009 ft) - 290 metres (950 ft)Plutonium surface ejecta studies.
ClarinetFebruary 9, 1999NTS Area U1a.101C 37°00′36″N116°03′32″W / 37.01003°N 116.05898°W / 37.01003; -116.05898 1,222 metres (4,009 ft) - 290 metres (950 ft)Holog and Clarinet may have switched places on the map.
OboeSeptember 30, 1999NTS Area U1a.102C 37°00′39″N116°03′32″W / 37.01095°N 116.05877°W / 37.01095; -116.05877 1,222 metres (4,009 ft) - 290 metres (950 ft)
Oboe 2November 9, 1999NTS Area U1a.102C 37°00′39″N116°03′32″W / 37.01095°N 116.05877°W / 37.01095; -116.05877 1,222 metres (4,009 ft) - 290 metres (950 ft)
Oboe 3February 3, 2000NTS Area U1a.102C 37°00′39″N116°03′32″W / 37.01095°N 116.05877°W / 37.01095; -116.05877 1,222 metres (4,009 ft) - 290 metres (950 ft)
ThoroughbredMarch 22, 2000NTS Area U1a 37°00′41″N116°03′35″W / 37.01139°N 116.05983°W / 37.01139; -116.05983 1,222 metres (4,009 ft) - 290 metres (950 ft)Plutonium surface ejecta studies, followup to Cimarron.
Oboe 4April 6, 2000NTS Area U1a.102C 37°00′39″N116°03′32″W / 37.01095°N 116.05877°W / 37.01095; -116.05877 1,222 metres (4,009 ft) - 290 metres (950 ft)
Oboe 5August 18, 2000NTS Area U1a.102C 37°00′39″N116°03′32″W / 37.01095°N 116.05877°W / 37.01095; -116.05877 1,222 metres (4,009 ft) - 290 metres (950 ft)
Oboe 6December 14, 2000NTS Area U1a.102C 37°00′39″N116°03′32″W / 37.01095°N 116.05877°W / 37.01095; -116.05877 1,222 metres (4,009 ft) - 290 metres (950 ft)
Oboe 8September 26, 2001NTS Area U1a.102C 37°00′39″N116°03′32″W / 37.01095°N 116.05877°W / 37.01095; -116.05877 1,222 metres (4,009 ft) - 290 metres (950 ft)
Oboe 7December 13, 2001NTS Area U1a.102C 37°00′39″N116°03′32″W / 37.01095°N 116.05877°W / 37.01095; -116.05877 1,222 metres (4,009 ft) - 290 metres (950 ft)
Oboe 9June 7, 2002 21:46:--NTS Area U1a.102C 37°00′39″N116°03′32″W / 37.01095°N 116.05877°W / 37.01095; -116.05877 1,222 metres (4,009 ft) - 290 metres (950 ft)
MarioAugust 29, 2002 19:00:--NTS Area U1a 37°00′41″N116°03′35″W / 37.01139°N 116.05983°W / 37.01139; -116.05983 1,222 metres (4,009 ft) - 290 metres (950 ft)Plutonium surface studies (optical analysis of spall). Used wrought plutonium from Rocky Flats.
RoccoSeptember 26, 2002 19:00:--NTS Area U1a 37°00′41″N116°03′35″W / 37.01139°N 116.05983°W / 37.01139; -116.05983 1,222 metres (4,009 ft) - 290 metres (950 ft)Plutonium surface studies (optical analysis of spall), followup to Mario. Used cast plutonium from Los Alamos.
PianoSeptember 19, 2003 20:44:--NTS Area U1a.102C 37°00′39″N116°03′32″W / 37.01095°N 116.05877°W / 37.01095; -116.05877 1,222 metres (4,009 ft) - 290 metres (950 ft)
ArmandoMay 25, 2004NTS Area U1a 37°00′41″N116°03′35″W / 37.01139°N 116.05983°W / 37.01139; -116.05983 1,222 metres (4,009 ft) - 290 metres (950 ft)Plutonium spall measurements using x-ray analysis. [lower-alpha 2]
Step WedgeApril 1, 2005NTS Area U1a 37°00′41″N116°03′35″W / 37.01139°N 116.05983°W / 37.01139; -116.05983 1,222 metres (4,009 ft) - 190 metres (620 ft)April–May 2005, a series of mini-hydronuclear experiments interpreting Armando results.
UnicornAugust 31, 2006 01:00:--NTS Area U6c 36°59′12″N116°02′38″W / 36.98663°N 116.0439°W / 36.98663; -116.0439 1,222 metres (4,009 ft) - 190 metres (620 ft)"…confirm nuclear performance of the W88 warhead with a newly-manufactured pit." Early pit studies.
ThermosJanuary 1, 2007NTS Area U1a 37°00′41″N116°03′35″W / 37.01139°N 116.05983°W / 37.01139; -116.05983 1,222 metres (4,009 ft) - 190 metres (620 ft)Feb-6 thru May 3, 2007, 12 mini-hydronuclear experiments in thermos-sized flasks.
BacchusSeptember 16, 2010NTS Area U1a.05? 37°00′41″N116°03′35″W / 37.01139°N 116.05983°W / 37.01139; -116.05983 1,222 metres (4,009 ft) - 190 metres (620 ft)
Barolo ADecember 1, 2010NTS Area U1a.05? 37°00′41″N116°03′35″W / 37.01139°N 116.05983°W / 37.01139; -116.05983 1,222 metres (4,009 ft) - 190 metres (620 ft)
Barolo BFebruary 2, 2011NTS Area U1a.05? 37°00′41″N116°03′35″W / 37.01139°N 116.05983°W / 37.01139; -116.05983 1,222 metres (4,009 ft) - 190 metres (620 ft)
CastorSeptember 1, 2012NTS Area U1a 37°00′41″N116°03′35″W / 37.01139°N 116.05983°W / 37.01139; -116.05983 1,222 metres (4,009 ft) - 190 metres (620 ft)Not even a subcrit, contained no plutonium; a dress rehearsal for Pollux.
PolluxDecember 5, 2012NTS Area U1a 37°00′41″N116°03′35″W / 37.01139°N 116.05983°W / 37.01139; -116.05983 1,222 metres (4,009 ft) - 190 metres (620 ft)A subcritical test with a scaled down warhead mockup. [lower-alpha 3]
LedaJune 15, 2014NTS Area U1a 37°00′41″N116°03′35″W / 37.01139°N 116.05983°W / 37.01139; -116.05983 1,222 metres (4,009 ft) - 190 metres (620 ft)Like Castor, the plutonium was replaced by a surrogate; this is a dress rehearsal for the later Lydia. The target was a weapons pit mock-up. [lower-alpha 4]
Lydia??-??-2015NTS Area U1a 37°00′41″N116°03′35″W / 37.01139°N 116.05983°W / 37.01139; -116.05983 1,222 metres (4,009 ft) - 190 metres (620 ft)Expected to be a plutonium subcritical test with a scaled down warhead mockup.[ citation needed ]

There have also been simulations of the effects of nuclear detonations using conventional explosives (such as the Minor Scale U.S. test in 1985). The explosives might be spiked with radioactive materials to simulate fallout dispersal.

History

The Phoenix of Hiroshima (foreground) in Hong Kong Harbor in 1967, was involved in several famous anti-nuclear protest voyages against nuclear testing in the Pacific. Phoenix en route to North Vietnam, 1967.jpg
The Phoenix of Hiroshima (foreground) in Hong Kong Harbor in 1967, was involved in several famous anti-nuclear protest voyages against nuclear testing in the Pacific.
The 6,900-square-mile (18,000 km) expanse of the Semipalatinsk Test Site (indicated in red), attached to Kurchatov (along the Irtysh river). The site comprised an area the size of Wales. Wfm sts overview.png
The 6,900-square-mile (18,000 km) expanse of the Semipalatinsk Test Site (indicated in red), attached to Kurchatov (along the Irtysh river). The site comprised an area the size of Wales.

The first atomic weapons test was conducted near Alamogordo, New Mexico, on July 16, 1945, during the Manhattan Project, and given the codename "Trinity". The test was originally to confirm that the implosion-type nuclear weapon design was feasible, and to give an idea of what the actual size and effects of a nuclear explosion would be before they were used in combat against Japan. While the test gave a good approximation of many of the explosion's effects, it did not give an appreciable understanding of nuclear fallout, which was not well understood by the project scientists until well after the atomic bombings of Hiroshima and Nagasaki.

The United States conducted six atomic tests before the Soviet Union developed their first atomic bomb (RDS-1) and tested it on August 29, 1949. Neither country had very many atomic weapons to spare at first, and so testing was relatively infrequent (when the U.S. used two weapons for Operation Crossroads in 1946, they were detonating over 20% of their current arsenal). However, by the 1950s the United States had established a dedicated test site on its own territory (Nevada Test Site) and was also using a site in the Marshall Islands (Pacific Proving Grounds) for extensive atomic and nuclear testing.

The early tests were used primarily to discern the military effects of atomic weapons (Crossroads had involved the effect of atomic weapons on a navy, and how they functioned underwater) and to test new weapon designs. During the 1950s, these included new hydrogen bomb designs, which were tested in the Pacific, and also new and improved fission weapon designs. The Soviet Union also began testing on a limited scale, primarily in Kazakhstan. During the later phases of the Cold War, though, both countries developed accelerated testing programs, testing many hundreds of bombs over the last half of the 20th century.

In 1954 the Castle Bravo fallout plume spread dangerous levels of radiation over an area over 100 miles (160 km) long, including inhabited islands. Bravo fallout2.png
In 1954 the Castle Bravo fallout plume spread dangerous levels of radiation over an area over 100 miles (160 km) long, including inhabited islands.

Atomic and nuclear tests can involve many hazards. Some of these were illustrated in the U.S. Castle Bravo test in 1954. The weapon design tested was a new form of hydrogen bomb, and the scientists underestimated how vigorously some of the weapon materials would react. As a result, the explosion—with a yield of 15 Mt—was over twice what was predicted. Aside from this problem, the weapon also generated a large amount of radioactive nuclear fallout, more than had been anticipated, and a change in the weather pattern caused the fallout to spread in a direction not cleared in advance. The fallout plume spread high levels of radiation for over 100 miles (160 km), contaminating a number of populated islands in nearby atoll formations. Though they were soon evacuated, many of the islands' inhabitants suffered from radiation burns and later from other effects such as increased cancer rate and birth defects, as did the crew of the Japanese fishing boat Daigo Fukuryū Maru . One crewman died from radiation sickness after returning to port, and it was feared that the radioactive fish they had been carrying had made it into the Japanese food supply.

Because of concerns about worldwide fallout levels, the Partial Test Ban Treaty was signed in 1963. Above are the per capita thyroid doses (in rads) in the continental United States resulting from all exposure routes from all atmospheric nuclear tests conducted at the Nevada Test Site from 1951 to 1962. US fallout exposure.png
Because of concerns about worldwide fallout levels, the Partial Test Ban Treaty was signed in 1963. Above are the per capita thyroid doses (in rads) in the continental United States resulting from all exposure routes from all atmospheric nuclear tests conducted at the Nevada Test Site from 1951 to 1962.

Castle Bravo was the worst U.S. nuclear accident, but many of its component problems—unpredictably large yields, changing weather patterns, unexpected fallout contamination of populations and the food supply—occurred during other atmospheric nuclear weapons tests by other countries as well. Concerns over worldwide fallout rates eventually led to the Partial Test Ban Treaty in 1963, which limited signatories to underground testing. Not all countries stopped atmospheric testing, but because the United States and the Soviet Union were responsible for roughly 86% of all nuclear tests, their compliance cut the overall level substantially. France continued atmospheric testing until 1974, and China until 1980.

A tacit moratorium on testing was in effect from 1958 to 1961, and ended with a series of Soviet tests in late 1961, including the Tsar Bomba, the largest nuclear weapon ever tested. The United States responded in 1962 with Operation Dominic, involving dozens of tests, including the explosion of a missile launched from a submarine.

Almost all new nuclear powers have announced their possession of nuclear weapons with a nuclear test. The only acknowledged nuclear power that claims never to have conducted a test was South Africa (although see Vela Incident), which has since dismantled all of its weapons. Israel is widely thought to possess a sizable nuclear arsenal, though it has never tested, unless they were involved in Vela. Experts disagree on whether states can have reliable nuclear arsenals—especially ones using advanced warhead designs, such as hydrogen bombs and miniaturized weapons—without testing, though all agree that it is very unlikely to develop significant nuclear innovations without testing. One other approach is to use supercomputers to conduct "virtual" testing, but codes need to be validated against test data.

There have been many attempts to limit the number and size of nuclear tests; the most far-reaching is the Comprehensive Test Ban Treaty of 1996, which has not, as of 2013, been ratified by eight of the "Annex 2 countries" required for it to take effect, including the United States. Nuclear testing has since become a controversial issue in the United States, with a number of politicians saying that future testing might be necessary to maintain the aging warheads from the Cold War. Because nuclear testing is seen as furthering nuclear arms development, many are opposed to future testing as an acceleration of the arms race.

In total nuclear test megatonnage, from 1945 to 1992, 520 atmospheric nuclear explosions (including eight underwater) have been conducted with a total yield of 545 megatons, [14] with a peak occurring in 1961–1962, when 340 megatons were detonated in the atmosphere by the United States and Soviet Union. [15] while the estimated number of underground nuclear tests conducted in the period from 1957 to 1992 is 1,352 explosions with a total yield of 90 Mt. [14]

Nuclear testing by country

Over 2,000 nuclear tests have been conducted, in over a dozen different sites around the world. Red Russia/Soviet Union, blue France, light blue United States, violet Britain, black Israel, orange India, yellow China, brown Pakistan, green North Korea and light green (territories exposed to nuclear bombs) Rael Nuclear use locations world map.png
Over 2,000 nuclear tests have been conducted, in over a dozen different sites around the world. Red Russia/Soviet Union, blue France, light blue United States, violet Britain, black Israel, orange India, yellow China, brown Pakistan, green North Korea and light green (territories exposed to nuclear bombs)
"Baker Shot", part of Operation Crossroads, a nuclear test by the United States at Bikini Atoll in 1946 Operation Crossroads Baker Edit.jpg
"Baker Shot", part of Operation Crossroads, a nuclear test by the United States at Bikini Atoll in 1946

The nuclear powers have conducted more than 2,000 nuclear test explosions (numbers are approximate, as some test results have been disputed):

There may also have been at least three alleged but unacknowledged nuclear explosions (see list of alleged nuclear tests) including the Vela Incident.

From the first nuclear test in 1945 until tests by Pakistan in 1998, there was never a period of more than 22 months with no nuclear testing. June 1998 to October 2006 was the longest period since 1945 with no acknowledged nuclear tests.

A summary table of all the nuclear testing that has happened since 1945 is here: Worldwide nuclear testing counts and summary.

Graph of nuclear testing Worldwide nuclear testing multilang.svg
Graph of nuclear testing

Treaties against testing

There are many existing anti-nuclear explosion treaties, notably the Partial Nuclear Test Ban Treaty and the Comprehensive Nuclear Test Ban Treaty. These treaties were proposed in response to growing international concerns about environmental damage among other risks. Nuclear testing involving humans also contributed to the formation of these treaties. Examples can be seen in the following articles:

The Partial Nuclear Test Ban treaty makes it illegal to detonate any nuclear explosion anywhere except underground, in order to reduce atmospheric fallout. Most countries have signed and ratified the Partial Nuclear Test Ban, which went into effect in October 1963. Of the nuclear states, France, China, and North Korea have never signed the Partial Nuclear Test Ban Treaty. [24]

The 1996 Comprehensive Nuclear-Test-Ban Treaty (CTBT) bans all nuclear explosions everywhere, including underground. For that purpose, the Preparatory Commission of the Comprehensive Nuclear-Test-Ban Treaty Organization is building an international monitoring system with 337 facilities located all over the globe. 85% of these facilities are already operational. [25] As of May 2012, the CTBT has been signed by 183 States, of which 157 have also ratified. However, for the Treaty to enter into force it needs to be ratified by 44 specific nuclear technology-holder countries. These "Annex 2 States" participated in the negotiations on the CTBT between 1994 and 1996 and possessed nuclear power or research reactors at that time. The ratification of eight Annex 2 states is still missing: China, Egypt, Iran, Israel and the United States have signed but not ratified the Treaty; India, North Korea and Pakistan have not signed it. [26]

The following is a list of the treaties applicable to nuclear testing:

NameAgreement dateIn force dateIn effect today?Notes
Unilateral USSR banMarch 31, 1958March 31, 1958noUSSR unilaterally stops testing provided the West does as well.
Bilateral testing banAugust 2, 1958August 2, 1958noUSA agrees; ban begins on 31 October 1958, 3 November 1958 for the Soviets, and lasts until abrogated by a USSR test on 1 September 1961.
Antarctic Treaty System December 1, 1959June 23, 1961yesBans testing of all kinds in Antarctica.
Partial Nuclear Test Ban Treaty (PTBT)August 5, 1962October 10, 1963yesBan on all but underground testing.
Outer Space Treaty January 27, 1967October 10, 1967yesBans testing on the moon and other celestial bodies.
Treaty of Tlatelolco February 14, 1967April 22, 1968yesBans testing in South America and the Caribbean Sea Islands.
Nuclear Non-proliferation Treaty January 1, 1968March 5, 1970yesBans the proliferation of nuclear technology to non-nuclear nations.
Seabed Arms Control Treaty February 11, 1971May 18, 1972yesBans emplacement of nuclear weapons on the ocean floor outside territorial waters.
Strategic Arms Limitation Treaty (SALT I)January 1, 1972noA five-year ban on installing launchers.
Anti-Ballistic Missile Treaty May 26, 1972August 3, 1972noRestricts ABM development; additional protocol added in 1974; abrogated by the USA in 2002.
Agreement on the Prevention of Nuclear War June 22, 1973June 22, 1973yesPromises to make all efforts to promote security and peace.
Threshold Test Ban Treaty July 1, 1974December 11, 1990yesProhibits higher than 150 kt for underground testing.
Peaceful Nuclear Explosions Treaty (PNET)January 1, 1976December 11, 1990yesProhibits higher than 150 kt, or 1500kt in aggregate, testing for peaceful purposes.
Moon Treaty January 1, 1979January 1, 1984noBans use and emplacement of nuclear weapons on the moon and other celestial bodies.
Strategic Arms Limitations Treaty (SALT II)June 18, 1979noLimits strategic arms. Kept but not ratified by the US, abrogated in 1986.
Treaty of Rarotonga August 6, 1985?Bans nuclear weapons in South Pacific Ocean and islands. US never ratified.
Intermediate Range Nuclear Forces Treaty (INF)December 8, 1987June 1, 1988yesEliminates Intermediate Range Ballistic Missiles (IRBMs). Implemented by 1 June 1991. Both sides allege the other is in violation of the treaty.
Treaty on Conventional Armed Forces in Europe November 19, 1990July 17, 1992yesBans categories of weapons, including conventional, from Europe. Russia notified signatories of intent to suspend, 14 July 2007.
Strategic Arms Reduction Treaty I (START I) July 31, 1991December 5, 1994no35-40% reduction in ICBMs with verification. Treaty expired 5 December 2009, renewed (see below).
Treaty on Open Skies March 24, 1992January 1, 2002yesAllows for unencumbered surveillance over all signatories.
US unilateral testing moratorium October 2, 1992October 2, 1992noGeorge. H. W. Bush declares unilateral ban on nuclear testing. [27] Extended several times, not yet abrogated.
Strategic Arms Reduction Treaty (START II) January 3, 1993January 1, 2002noDeep reductions in ICBMs. Abrogated by Russia in 2002 in retaliation of US abrogation of ABM Treaty.
Southeast Asian Nuclear-Weapon-Free Zone Treaty (Treaty of Bangkok)December 15, 1995March 28, 1997yesBans nuclear weapons from southeast Asia.
African Nuclear Weapon Free Zone Treaty (Pelindaba Treaty)January 1, 1996July 16, 2009yesBans nuclear weapons in Africa.
Comprehensive Nuclear Test Ban Treaty (CTBT)September 10, 1996yes (effectively)Bans all nuclear testing, peaceful and otherwise. Strong detection and verification mechanism (CTBTO). US has signed and adheres to the treaty, though has not ratified it.
Treaty on Strategic Offensive Reductions (SORT, Treaty of Moscow)May 24, 2002June 1, 2003noReduces warheads to 1700-2200 in ten years. Expired, replaced by START II.
START I treaty renewalApril 8, 2010January 26, 2011yesSame provisions as START I.

Compensation for victims

Over 500 atmospheric nuclear weapons tests were conducted at various sites around the world from 1945 to 1980. 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 nuclear fallout might have led to approximately 11,000 excess deaths, most caused by thyroid cancer linked to exposure to iodine-131. [28]

Milestone nuclear explosions

The following list is of milestone nuclear explosions. In addition to the atomic bombings of Hiroshima and Nagasaki, the first nuclear test of a given weapon type for a country is included, and tests which were otherwise notable (such as the largest test ever). All yields (explosive power) are given in their estimated energy equivalents in kilotons of TNT (see TNT equivalent). Putative tests (like Vela Incident) have not been included.

DateName Yield (kt)CountrySignificance
1945-07-16 Trinity 18–20 USA First fission device test, first plutonium implosion detonation
1945-08-06 Little Boy 12–18 USA Bombing of Hiroshima, Japan, first detonation of a uranium gun-type device, first use of a nuclear device in combat.
1945-08-09 Fat Man 18–23 USA Bombing of Nagasaki, Japan, second detonation of a plutonium implosion device (the first being the Trinity Test), second and last use of a nuclear device in combat.
1949-08-29 RDS-1 22 USSR First fission weapon test by the USSR
1952-10-03 Hurricane 25 UK First fission weapon test by the UK
1952-11-01 Ivy Mike 10,400 USA First cryogenic fusion fuel "staged" thermonuclear weapon, primarily a test device and not weaponized
1952-11-16 Ivy King 500 USA Largest pure-fission weapon ever tested
1953-08-12 Joe 4 400 USSR First fusion weapon test by the USSR (not "staged")
1954-03-01 Castle Bravo 15,000 USA First dry fusion fuel "staged" thermonuclear weapon; a serious nuclear fallout accident occurred; largest nuclear detonation conducted by United States
1955-11-22 RDS-37 1,600 USSR First "staged" thermonuclear weapon test by the USSR (deployable)
1957-05-31 Orange Herald 720 UK Largest boosted fission weapon ever tested. Intended as a fallback "in megaton range" in case British thermonuclear development failed.
1957-11-08 Grapple X 1,800 UK First (successful) "staged" thermonuclear weapon test by the UK
1960-02-13 Gerboise Bleue 70 France First fission weapon test by France
1961-10-31 Tsar Bomba 50,000 USSR Largest thermonuclear weapon ever tested—scaled down from its initial 100 Mt design by 50%
1964-10-16 596 22 PR China First fission weapon test by the People's Republic of China
1967-06-17 Test No. 6 3,300 PR China First "staged" thermonuclear weapon test by the People's Republic of China
1968-08-24 Canopus 2,600 France First "staged" thermonuclear weapon test by France
1974-05-18 Smiling Buddha 12 India First fission nuclear explosive test by India
1998-05-11 Pokhran-II 45-50 India First potential fusion/boosted weapon test by India; first deployable fission weapon test by India
1998-05-28 Chagai-I 40 [31] Pakistan First fission weapon (boosted) test by Pakistan
2006-10-09 2006 North Korean nuclear test under 1 North Korea First fission weapon test by North Korea (plutonium-based)
2017-09-03 2017 North Korean nuclear test 200-300 North Korea First "staged" thermonuclear weapon test claimed by North Korea

"Staging" refers to whether it was a "true" hydrogen bomb of the so-called Teller-Ulam configuration or simply a form of a boosted fission weapon. For a more complete list of nuclear test series, see List of nuclear tests. Some exact yield estimates, such as that of the Tsar Bomba and the tests by India and Pakistan in 1998, are somewhat contested among specialists.

See also

Notes

  1. Universal Time at the Nevada National Security Site is 8 hours after local time; UT dates are one day after local date for UT times after 16:00.
  2. A video of the Armando test on YouTube
  3. A video of the Pollux test on YouTube
  4. A video of the Leda test on YouTube

Citations

  1. "The Treaty has not been signed by France or by the People's Republic of China." U.S. Department of State, Limited Test Ban Treaty.
  2. For an overview of the preparations and considerations used in underground nuclear testing, see ""Underground Nuclear Weapons Testing" (Globalsecurity.org)" . Retrieved 2006-10-19. For a longer and more technical discussion, see U.S. Congress, Office of Technology Assessment (October 1989). The Containment of Underground Nuclear Explosions (PDF). Washington, D.C.: U.S. Government Printing Office. Archived from the original (PDF) on 2013-02-27. Retrieved 2018-12-24.
  3. Yang, Xiaoping; North, Robert; Romney, Carl; Richards, Paul R. "Worldwide Nuclear Explosions" (PDF).
  4. Carey Sublette (9 August 2001), Nuclear Weapons Frequently Asked Questions, section 4.1.9, retrieved 10 April 2011
  5. Jonathan Medalia (12 March 2008), Comprehensive Nuclear-Test-Ban Treaty: Issues and Arguments (PDF), Congressional Research Service, pp. 20–22, retrieved 9 December 2013
  6. Medalia, Jonathan (2005-03-11). "Nuclear Weapons: Comprehensive Test Ban Treaty" (PDF) (IB92099). Congressional Record Service. Retrieved 2013-12-09.
  7. "US conducts 'subcritical' nuclear test". zeenews.india.com. 2012-12-07. Retrieved 2013-05-28.
  8. Thomas Nilsen (2 October 2012). "Subcritical nuke tests may be resumed at Novaya Zemlya". barentsobserver.com. Retrieved 2017-07-13.
  9. Papazian, Ghazar R.; Reinovsky, Robert E.; Beatty, Jerry N. (2003). "The New World of the Nevada Test Site" (PDF). Los Alamos Science (28). Retrieved 2013-12-12.
  10. Thorn, Robert N.; Westervelt, Donald R. (February 1, 1987). "Hydronuclear Experiments" (PDF). LANL Report LA-10902-MS. Retrieved December 9, 2013.
  11. Conrad, David C. (July 1, 2000). "Underground explosions are music to their ears". Science and Technology Review. Retrieved 9 December 2013.
  12. "Nevada Test Site: U1a Complex subcritical experiments". DOE Nevada. Department of Energy. 2003-02-01.
  13. Togzhan Kassenova (28 September 2009). "The lasting toll of Semipalatinsk's nuclear testing". Bulletin of the Atomic Scientists.
  14. 1 2 Pavlovski, O. A. (1 January 1998). "Radiological Consequences of Nuclear Testing for the Population of the Former USSR (Input Information, Models, Dose, and Risk Estimates)". Atmospheric Nuclear Tests. Springer, Berlin, Heidelberg. pp. 219–260. doi:10.1007/978-3-662-03610-5_17. ISBN   978-3-642-08359-4.
  15. "Radioactive Fallout - Worldwide Effects of Nuclear War - Historical Documents". Atomciarchive.com.
  16. "United States Nuclear Tests: July 1945 through September 1992" (PDF). Las Vegas, NV: Department of Energy, Nevada Operations Office. 2000-12-01. Archived from the original (PDF) on 2006-10-12. Retrieved 2013-12-18. This is usually cited as the "official" US list.
  17. Long, Kat. "Blasts from the Past: Old Nuke Test Films Offer New Insights [Video]". Scientific American. Retrieved 2017-04-24.
  18. "USSR Nuclear Weapons Tests and Peaceful Nuclear Explosions 1949 through 1990". Sarov, Russia: RFNC-VNIIEF. 1996. The official Russian list of Soviet tests.
  19. Mikhailov, Editor in Chief, V.N.; Andryushin, L.A.; Voloshin, N.P.; Ilkaev, R.I.; Matushchenko, A.M.; Ryabev, L.D.; Strukov, V.G.; Chernyshev, A.K.; Yudin, Yu.A. "Catalog of Worldwide Nuclear Testing". Archived from the original on 2013-12-19. Retrieved 2013-12-28.An equivalent list available on the internet.
  20. "UK/US Agreement". Archived from the original on 2007-06-07. Retrieved 2010-10-21.
  21. "N° 3571.- Rapport de MM. Christian Bataille et Henri Revol sur les incidences environnementales et sanitaires des essais nucléaires effectués par la France entre 1960 et 1996 (Office d'évaluation des choix scientifiques et technologiques)". Assemblee-nationale.fr. Retrieved 2010-10-21.
  22. "Nuclear Weapons Test List". Fas.org. Retrieved 22 September 2018.
  23. "Archived copy". Archived from the original on 2012-04-27. Retrieved 2018-12-24.CS1 maint: Archived copy as title (link)
  24. U.S. Department of State, Limited Test Ban Treaty.
  25. "CTBTO Factsheet: Ending Nuclear Explosions" (PDF). Ctbto.org. Retrieved 2012-05-23.
  26. "Status of signature and ratification". Ctbto.org. Retrieved 2012-05-23.
  27. "The Status of the Comprehensive Test Ban Treaty: Signatories and Ratifiers". Arms Control Association. March 2014. Retrieved June 29, 2014.
  28. Council, National Research (11 February 2003). Exposure of the American Population to Radioactive Fallout from Nuclear Weapons Tests: A Review of the CDC-NCI Draft Report on a Feasibility Study of the Health Consequences to the American Population from Nuclear Weapons Tests Conducted by the United States and Other Nations. doi:10.17226/10621. ISBN   9780309087131. PMID   25057651.
  29. 1 2 3 4 5 News, A. B. C. "International News: Latest Headlines, Video and Photographs from Around the World -- People, Places, Crisis, Conflict, Culture, Change, Analysis and Trends". Abcnews.go.com.
  30. "Radiation Exposure Compensation System: Claims to Date Summary of Claims Received by 06/11/2009" (PDF). Usdoj.gov.
  31. Pakistan Nuclear Weapons. Federation of American Scientists. December 11, 2002

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References