The Comprehensive Nuclear-Test-Ban Treaty (CTBT) is a
multilateral treaty
A multilateral treaty or multilateral agreement is a treaty to which two or more sovereign states are parties. Each party owes the same obligations to all other parties, except to the extent that they have stated reservation (law), reservations. Ex ...
to ban
nuclear weapons test explosions and any other
nuclear explosions, for both civilian and military purposes, in all environments. It was adopted by the
United Nations General Assembly
The United Nations General Assembly (UNGA or GA; , AGNU or AG) is one of the six principal organs of the United Nations (UN), serving as its main deliberative, policymaking, and representative organ. Currently in its Seventy-ninth session of th ...
on 10 September 1996, but has not
entered into force, as nine specific nations have not ratified the treaty.
History
Background
The movement for international control of
nuclear weapon
A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission or atomic bomb) or a combination of fission and fusion reactions (thermonuclear weapon), producing a nuclear exp ...
s began in 1945, with a call from Canada and the United Kingdom for a conference on the subject. In June 1946,
Bernard Baruch, an emissary of President
Harry S. Truman
Harry S. Truman (May 8, 1884December 26, 1972) was the 33rd president of the United States, serving from 1945 to 1953. As the 34th vice president in 1945, he assumed the presidency upon the death of Franklin D. Roosevelt that year. Subsequen ...
, proposed the
Baruch Plan before the United Nations Atomic Energy Commission, which called for an international system of controls on the production of atomic energy. The plan, which would serve as the basis for U.S. nuclear policy into the 1950s, was rejected by the
Soviet Union
The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...
as a US ploy to cement its nuclear dominance.
Between the
Trinity nuclear test of 16 July 1945 and the signing of the
Partial Test Ban Treaty
The Partial Test Ban Treaty (PTBT), formally known as the 1963 Treaty Banning Nuclear Weapon Tests in the Atmosphere, in Outer Space and Under Water, prohibited all nuclear weapons testing, test detonations of nuclear weapons except for those co ...
(PTBT) on 5 August 1963, 499 nuclear tests were conducted.
Much of the impetus for the PTBT, the precursor to the CTBT, was rising public concern surrounding the size and resulting
nuclear fallout
Nuclear fallout is residual radioactive material that is created by the reactions producing a nuclear explosion. It is initially present in the mushroom cloud, radioactive cloud created by the explosion, and "falls out" of the cloud as it is ...
from underwater and atmospheric nuclear tests, particularly tests of powerful
thermonuclear weapons
A thermonuclear weapon, fusion weapon or hydrogen bomb (H-bomb) is a second-generation nuclear weapon design. Its greater sophistication affords it vastly greater destructive power than first-generation nuclear bombs, a more compact size, a lowe ...
(hydrogen bombs). The
Castle Bravo
Castle Bravo was the first in a series of high-yield thermonuclear weapon design tests conducted by the United States at Bikini Atoll, Marshall Islands, as part of ''Operation Castle''. Detonated on 1 March 1954, the device remains the most powe ...
test of 1 March 1954, in particular, attracted significant attention as the detonation resulted in fallout that spread over inhabited areas and sickened a group of Japanese fishermen.
Between 1945 and 1963, the US conducted 215 atmospheric tests, the Soviet Union conducted 219, the UK conducted 21, and
France
France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...
conducted 4.
In 1954, following the Castle Bravo test, Prime Minister
Jawaharlal Nehru
Jawaharlal Nehru (14 November 1889 – 27 May 1964) was an Indian anti-colonial nationalist, secular humanist, social democrat, and statesman who was a central figure in India during the middle of the 20th century. Nehru was a pr ...
of
India
India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...
issued the first appeal for a "standstill agreement" on testing, which was soon echoed by the British
Labour Party.
Negotiations on a comprehensive test ban, primarily involving the US, UK, and the Soviet Union, began in 1955 following a proposal by Soviet leader
Nikita Khrushchev
Nikita Sergeyevich Khrushchev (– 11 September 1971) was the General Secretary of the Communist Party of the Soviet Union, First Secretary of the Communist Party of the Soviet Union from 1953 to 1964 and the Premier of the Soviet Union, Chai ...
. Of primary concern throughout the negotiations, which would stretch—with some interruptions—to July 1963, was the system of verifying compliance with the test ban and detecting illicit tests. On the Western side, there were concerns that the Soviet Union would be able to circumvent any test ban and secretly leap ahead in the
nuclear arms race
The nuclear arms race was an arms race competition for supremacy in nuclear warfare between the United States, the Soviet Union, and their respective allies during the Cold War. During this same period, in addition to the American and Soviet nuc ...
. These fears were amplified following the US
''Rainier'' shot of 19 September 1957, which was the first contained underground test of a nuclear weapon. Though the US held a significant advantage in underground testing capabilities, there was worry that the Soviet Union would be able to covertly conduct underground tests during a test ban, as underground detonations were more challenging to detect than above-ground tests. On the Soviet side, conversely, the on-site compliance inspections demanded by the US and UK were seen as amounting to espionage. Disagreement over verification would lead to the Anglo-American and Soviet negotiators abandoning a comprehensive test ban (i.e., a ban on all tests, including those underground) in favor of a partial ban, which would be finalized on 25 July 1963. The PTBT, joined by 123 states following the original three parties, banned detonations for military and civilian purposes underwater, in the atmosphere, and outer space.
The PTBT had mixed results. On the one hand, enactment of the treaty was followed by a substantial drop in the atmospheric concentration of radioactive particles.
On the other hand,
nuclear proliferation
Nuclear proliferation is the spread of nuclear weapons to additional countries, particularly those not recognized as List of states with nuclear weapons, nuclear-weapon states by the Treaty on the Non-Proliferation of Nuclear Weapons, commonl ...
was not halted entirely (though it may have been slowed) and nuclear testing continued at a rapid clip. Compared to the 499 tests from 1945 to the signing of the PTBT, 436 tests were conducted over the ten years following the PTBT. Furthermore, US and Soviet underground testing continued "venting" radioactive gas into the atmosphere.
Additionally, though underground testing was generally safer than above-ground testing, underground tests continued to risk the leaking of
radionuclide
A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess numbers of either neutrons or protons, giving it excess nuclear energy, and making it unstable. This excess energy can be used in one of three ...
s, including
plutonium
Plutonium is a chemical element; it has symbol Pu and atomic number 94. It is a silvery-gray actinide metal that tarnishes when exposed to air, and forms a dull coating when oxidized. The element normally exhibits six allotropes and four ...
, into the ground. From 1964 through 1996, the year of the CTBT's adoption, an estimated 1,377 underground nuclear tests were conducted. The final non-underground (atmospheric or underwater) test was conducted by China in 1980.
The PTBT has been seen as a step towards the
Nuclear Non-proliferation Treaty
The Treaty on the Non-Proliferation of Nuclear Weapons, commonly known as the Non-Proliferation Treaty or NPT, is an international treaty whose objective is to prevent the spread of nuclear weapons and weapons technology, to promote cooperatio ...
(NPT) of 1968, which directly referenced the PTBT.
Under the NPT, non-nuclear weapon states were prohibited from possessing, manufacturing, and acquiring nuclear weapons or other nuclear explosive devices. All signatories, including nuclear weapon states, were committed to the goal of total
nuclear disarmament
Nuclear disarmament is the act of reducing or eliminating nuclear weapons. Its end state can also be a nuclear-weapons-free world, in which nuclear weapons are completely eliminated. The term ''denuclearization'' is also used to describe the pro ...
. However,
India
India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...
,
Pakistan
Pakistan, officially the Islamic Republic of Pakistan, is a country in South Asia. It is the List of countries and dependencies by population, fifth-most populous country, with a population of over 241.5 million, having the Islam by country# ...
, and
Israel
Israel, officially the State of Israel, is a country in West Asia. It Borders of Israel, shares borders with Lebanon to the north, Syria to the north-east, Jordan to the east, Egypt to the south-west, and the Mediterranean Sea to the west. Isr ...
have declined to sign the NPT on the grounds that such a treaty is fundamentally discriminatory as it places limitations on states that do not have nuclear weapons while making no efforts to curb weapons development by declared nuclear weapons states.
A comprehensive ban
In 1974, a step towards a comprehensive test ban was made with the
Threshold Test Ban Treaty (TTBT), ratified by the US and Soviet Union, which banned underground tests with yields above 150 kilotons.
In April 1976, the two states reached agreement on the
Peaceful Nuclear Explosions Treaty (PNET), which concerns nuclear detonations outside the weapons sites discussed in the TTBT. As in the TTBT, the US and Soviet Union agreed to bar
peaceful nuclear explosions
Peaceful nuclear explosions (PNEs) are nuclear explosions conducted for non-military purposes. Proposed uses include excavation for the building of canals and harbours, electrical generation, the use of nuclear explosions to drive spacecraft, and a ...
(PNEs) at these other locations with yields above 150 kilotons, as well as group explosions with total yields over 1,500 kilotons. To verify compliance, the PNET requires that states rely on
national technical means of verification, share information on explosions, and grant on-site access to counterparties. The TTBT and PNET entered into force on 11 December 1990.

In October 1977, the US, UK, and Soviet Union returned to negotiations over a test ban. These three nuclear powers made notable progress in the late 1970s, agreeing to terms on a ban on all testing, including a temporary prohibition on PNEs, but continued disagreements over the compliance mechanisms led to an end to negotiations ahead of
Ronald Reagan
Ronald Wilson Reagan (February 6, 1911 – June 5, 2004) was an American politician and actor who served as the 40th president of the United States from 1981 to 1989. He was a member of the Republican Party (United States), Republican Party a ...
's inauguration as president in 1981.
In 1985, Soviet leader
Mikhail Gorbachev
Mikhail Sergeyevich Gorbachev (2 March 1931 – 30 August 2022) was a Soviet and Russian politician who served as the last leader of the Soviet Union from 1985 to dissolution of the Soviet Union, the country's dissolution in 1991. He served a ...
announced a unilateral testing moratorium, and in December 1986, Reagan reaffirmed US commitment to pursue the long-term goal of a comprehensive test ban. In February 1987, the Soviets ended their test moratorium as the US had not reciprocated. In November 1987, negotiations on a test ban restarted, followed by a joint US-Soviet program to research underground-test detection in December 1987.
Partially pressured by the protests causing the shutdown of the
Semipalatinsk Test Site, in October 1991, the Soviet Union announced another unilateral testing moratorium. Three days before its expiration,
George H. W. Bush
George Herbert Walker BushBefore the outcome of the 2000 United States presidential election, he was usually referred to simply as "George Bush" but became more commonly known as "George H. W. Bush", "Bush Senior," "Bush 41," and even "Bush th ...
signed into law a reciprocal testing moratorium. President
Bill Clinton
William Jefferson Clinton (né Blythe III; born August 19, 1946) is an American politician and lawyer who was the 42nd president of the United States from 1993 to 2001. A member of the Democratic Party (United States), Democratic Party, ...
later repeatedly extended this until the 1996 Treaty signature opening.
The Treaty was adopted by the
United Nations General Assembly
The United Nations General Assembly (UNGA or GA; , AGNU or AG) is one of the six principal organs of the United Nations (UN), serving as its main deliberative, policymaking, and representative organ. Currently in its Seventy-ninth session of th ...
on 10 September 1996.
[United Nations Treaty Collection (2009). ]
Comprehensive Nuclear-Test-Ban Treaty
". Retrieved 23 August 2009. It opened for signature in New York on 24 September 1996.
The United States was the first nation to sign the treaty. Ratification by the US Senate was delayed by almost three years. On 13 October 1999, the resolution to ratify the CTBT, including an amendment of six safeguards, was defeated by a 51-48 vote, mostly along party lines. Unlike previous nuclear treaties, which had weeks of committee hearings and days of floor consideration, the CTBT received zero committee hearing and 18 hours of floor consideration. It was the first security-related treaty to be rejected by the Senate since the
Treaty of Versailles
The Treaty of Versailles was a peace treaty signed on 28 June 1919. As the most important treaty of World War I, it ended the state of war between Germany and most of the Allies of World War I, Allied Powers. It was signed in the Palace ...
, 80 years prior.
In the aftermath, and leadup to the
2000 United States presidential election
United States presidential election, Presidential elections were held in the United States on November 7, 2000. Republican Party (United States), Republican Governor George W. Bush of Texas, the eldest son of 41st President George H. W. Bush, ...
, Republican candidates such as
George W. Bush
George Walker Bush (born July 6, 1946) is an American politician and businessman who was the 43rd president of the United States from 2001 to 2009. A member of the Bush family and the Republican Party (United States), Republican Party, he i ...
and
John McCain
John Sidney McCain III (August 29, 1936 – August 25, 2018) was an American statesman and United States Navy, naval officer who represented the Arizona, state of Arizona in United States Congress, Congress for over 35 years, first as ...
voiced their opposition to the CTBT, but support for the testing moratorium. Following Bush's election victory, there was speculation testing would resume, pointing to the CTBT's "supreme national interest" provision where nations may withdraw if they feel their security is threatened by deteriorating warheads.
In October 2023, Russian president
Vladimir Putin
Vladimir Vladimirovich Putin (born 7 October 1952) is a Russian politician and former intelligence officer who has served as President of Russia since 2012, having previously served from 2000 to 2008. Putin also served as Prime Minister of Ru ...
stated that since the United States had not ratified the CTBT, consideration could be given to
withdrawing Russia's ratification of the treaty. Later in the month, a law revoking ratification of the CTBT was passed by the Russian parliament. On 2 November, Putin officially signed into law the withdrawal of ratification of the treaty.
Negotiations
Given the political situation prevailing in the subsequent decades, little progress was made in nuclear disarmament until the end of the
Cold War
The Cold War was a period of global Geopolitics, geopolitical rivalry between the United States (US) and the Soviet Union (USSR) and their respective allies, the capitalist Western Bloc and communist Eastern Bloc, which lasted from 1947 unt ...
in 1991. Parties to the PTBT held an amendment conference that year to discuss a proposal to convert the Treaty into an instrument banning all nuclear-weapon tests. With strong support from the UN General Assembly, negotiations for a comprehensive test-ban treaty began in 1993.
Adoption
Extensive efforts were made over the next three years to draft the Treaty text and its two annexes. However, the
Conference on Disarmament
The Conference on Disarmament (CD) is a multilateral disarmament forum established by the international community to negotiate arms control and disarmament agreements based at the Palais des Nations in Geneva. The Conference meets annually in ...
, in which negotiations were being held, did not succeed in reaching consensus on the adoption of the text. Under the direction of Prime Minister
John Howard and Foreign Minister
Alexander Downer, Australia then sent the text to the
United Nations General Assembly
The United Nations General Assembly (UNGA or GA; , AGNU or AG) is one of the six principal organs of the United Nations (UN), serving as its main deliberative, policymaking, and representative organ. Currently in its Seventy-ninth session of th ...
in
New York, where it was submitted as a draft resolution. On 10 September 1996, the Comprehensive Test-Ban Treaty (CTBT) was adopted by a large majority, exceeding two-thirds of the General Assembly's Membership.
Obligations
(Article I):
# Each State Party undertakes not to carry out any
nuclear weapon
A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission or atomic bomb) or a combination of fission and fusion reactions (thermonuclear weapon), producing a nuclear exp ...
test explosion or any other nuclear explosion, and to prohibit and prevent any such nuclear explosion at any place under its jurisdiction or control.
# Each State Party undertakes, furthermore, to refrain from causing, encouraging, or in any way participating in the carrying out of any nuclear weapon test explosion or any other nuclear explosion.
Status
The Treaty was adopted by the
United Nations General Assembly
The United Nations General Assembly (UNGA or GA; , AGNU or AG) is one of the six principal organs of the United Nations (UN), serving as its main deliberative, policymaking, and representative organ. Currently in its Seventy-ninth session of th ...
on 10 September 1996.
It opened for signature in New York on 24 September 1996,
[United Nations Treaty Collection (2009). ]
Comprehensive Nuclear-Test-Ban Treaty
". Retrieved 23 August 2009. when it was signed by 71 states, including five of the eight then
nuclear-capable states. , 178 states have
ratified
Ratification is a principal's legal confirmation of an act of its agent. In international law, ratification is the process by which a state declares its consent to be bound to a treaty. In the case of bilateral treaties, ratification is usuall ...
the CTBT and another nine states have signed but not ratified it.
The treaty will enter into force 180 days after the 44 states listed in Annex 2 of the treaty have ratified it. These "Annex 2 states" are states that participated in the CTBT's negotiations between 1994 and 1996 and possessed nuclear power reactors or research reactors at that time. , nine Annex 2 states have not ratified the treaty: China, Egypt, Iran, Israel and the United States have signed but not ratified the Treaty; India, North Korea and Pakistan have not signed it; while
Russia
Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...
signed and ratified the treaty but subsequently withdrew its ratification prior to its entry into force.
Monitoring
Geophysical
Geophysics () is a subject of natural science concerned with the physical processes and properties of Earth and its surrounding space environment, and the use of quantitative methods for their analysis. Geophysicists conduct investigations acros ...
and other technologies are used to monitor for compliance with the Treaty:
forensic seismology, hydroacoustics,
infrasound
Infrasound, sometimes referred to as low frequency sound or incorrectly subsonic (subsonic being a descriptor for "less than the speed of sound"), describes sound waves with a Audio frequency, frequency below the lower limit of human audibility ...
, and
radionuclide
A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess numbers of either neutrons or protons, giving it excess nuclear energy, and making it unstable. This excess energy can be used in one of three ...
monitoring. The first three forms of monitoring are known as
wave-form measurements. Seismic monitoring is performed with a system of 50 primary stations located throughout the world, with 120 auxiliary stations in signatory states. Hydroacoustic monitoring is performed with a system of 11 stations that consist of
hydrophone triads to monitor for underwater explosions. Hydroacoustic stations can use seismometers to measure T-waves from possible underwater explosions instead of hydrophones. The best measurement of hydroacoustic waves has been found to be at a depth of 1000 m. Infrasound monitoring relies on changes in atmospheric pressure caused by a possible nuclear explosion, with 41 stations certified as of August 2019. One of the biggest concerns with infrasound measurements is noise due to exposure from wind, which can affect the sensor's ability to measure if an event occurred. Together, these technologies are used to monitor the ground, water, and atmosphere for any sign of a nuclear explosion.
Radionuclide monitoring takes the form of either monitoring for radioactive particulates or
noble gas
The noble gases (historically the inert gases, sometimes referred to as aerogens) are the members of Group (periodic table), group 18 of the periodic table: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn) and, in some ...
es as a product of a nuclear explosion. Radioactive particles emit radiation that can be measured by any of the 80 stations located throughout the world. They are created from nuclear explosions that can collect onto the dust that is moved from the explosion. If a nuclear explosion took place underground, noble gas monitoring can be used to verify whether or not a possible nuclear explosion took place. Noble gas monitoring relies on measuring increases in radioactive
xenon
Xenon is a chemical element; it has symbol Xe and atomic number 54. It is a dense, colorless, odorless noble gas found in Earth's atmosphere in trace amounts. Although generally unreactive, it can undergo a few chemical reactions such as the ...
gas. Different isotopes of xenon include
131mXe,
133Xe,
133mXe, and
135Xe. All four monitoring methods make up the International Monitoring System (IMS). Statistical theories and methods are integral to CTBT monitoring providing confidence in verification analysis. Once the Treaty enters into force, on-site inspections will be conducted where concerns about compliance arise.
The
Preparatory Commission for the
Comprehensive Test Ban Treaty Organization (CTBTO), an international organization headquartered in
Vienna
Vienna ( ; ; ) is the capital city, capital, List of largest cities in Austria, most populous city, and one of Federal states of Austria, nine federal states of Austria. It is Austria's primate city, with just over two million inhabitants. ...
, Austria, was created to build the verification framework, including establishment and provisional operation of the network of monitoring stations, the creation of an international data centre (IDC), and development of the on-site Inspection capability. The CTBTO is responsible for collecting information from the IMS and distribute the analyzed and raw data to member states to judge whether or not a nuclear explosion occurred through the IDC. Parameters such as determining the location where a nuclear explosion or test took place is one of the things that the IDC can accomplish. If a member state chooses to assert that another state had violated the CTBT, they can request an on-site inspection to take place to verify.
The monitoring network consists of 337 facilities located all over the globe. As of May 2012, more than 260 facilities have been certified. The monitoring stations register data that is transmitted to the international data centre in Vienna for processing and analysis. The data are sent to states that have signed the Treaty.
Possible violations
Fission yields
In 2020, the United States alleged that Russia had, between 1996 and 2019, carried out an unspecified number of low-yield nuclear test in underground facilities. It also alleged that China's 2019 expansion of the
Lop Nur
Lop Nur or Lop Nor (, , from an Oirat Mongolic name meaning "Lop Lake", where "Lop" is a toponym of unknown origin) is a now largely dried-up salt lake formerly located within the ''Lop Depression'' in the eastern fringe of the Tarim Basin in ...
test site would allow similar secret testing.
The United States also stated the
2019 Nyonoksa radiation accident and explosion in Russia involved a "nuclear reaction" i.e. a fission yield, which could be considered in violation of the Treaty despite not being an intentional test.
Extremely small fission yields are created during some
National Ignition Facility
The National Ignition Facility (NIF) is a laser-based inertial confinement fusion (ICF) research device, located at Lawrence Livermore National Laboratory in Livermore, California, United States. NIF's mission is to achieve fusion ignition wit ...
experiments (see below).
Inertial confinement fusion
Laser-driven
There is a question surrounding whether the experiments of
inertial confinement fusion
Inertial confinement fusion (ICF) is a fusion energy process that initiates nuclear fusion reactions by compressing and heating targets filled with fuel. The targets are small pellets, typically containing deuterium (2H) and tritium (3H).
Typical ...
facilities around the world, which initiate thermonuclear fusion in small deuterium-tritium pellets, qualify under the Treaty's total ban on the undertaking of all "nuclear explosions".
John Nuckolls, the
Livermore scientist credited as one of the pioneers of the field of ICF, himself described the fusion of less than one milligram of deuterium-tritium as an "explosion".
The American
National Ignition Facility
The National Ignition Facility (NIF) is a laser-based inertial confinement fusion (ICF) research device, located at Lawrence Livermore National Laboratory in Livermore, California, United States. NIF's mission is to achieve fusion ignition wit ...
, the French
Laser Mégajoule
Laser Mégajoule (LMJ) is a large laser-based inertial confinement fusion (ICF) research device near Bordeaux, France, built by the French nuclear science directorate, Commissariat à l'Énergie Atomique (CEA).
Laser Mégajoule plans to deliver ...
, and the Russian
ISKRA-5, all have a dual-use, supporting scientific research for both peaceful purposes, and for the continual verification and maintenance of their countries' thermonuclear weapon stockpile.
In the 1990s, the Treaty, and especially the "zero-yield" non-criticality standard for weapons-related fission testing, was the impetus for the American
Stockpile Stewardship and Management Program. Under this program, computational and experimental fusion research facilities were funded for weapon verification, including the magnetic confinement
Z Pulsed Power Facility, and the inertial laser implosion
OMEGA laser and the 1997
National Ignition Facility
The National Ignition Facility (NIF) is a laser-based inertial confinement fusion (ICF) research device, located at Lawrence Livermore National Laboratory in Livermore, California, United States. NIF's mission is to achieve fusion ignition wit ...
. In 1999 the US
Department of Energy, in response to concern from Senator
Tom Harkin, stated “NIF experiments are not considered nuclear explosions” and that “the large size of the facilities required to achieve inertial confinement fusion rules out weaponization”.
In 1998, Princeton policy researchers published "The question of pure fusion explosions under the CTBT". They sought a ban on testing above 10
14 neutrons, and on the use of tritium, which enhances the yield approximately twenty-fold versus deuterium-deuterium reactions, and forms the majority of the fusion yield in boosted and thermonuclear weapons.
These were not adopted, and fusion yield has increased 11,000 times since then.
In 2022, the NIF achieved 3.15 MJ and for the first time an
energy gain greater than one, equivalent to the chemical explosion of 752 grams of TNT, or three sticks of dynamite, and on a timescale of nanoseconds instead of a chemical explosive's milliseconds. This led to increased concern over the status of such experiments under the Treaty, and the development of
pure fusion weapons.
Non-laser-driven
In 1992, Russian scientists used high-explosive implosions to trigger fusion in less than a nanogram of deuterium-tritium gas, releasing 10
14 neutrons and the energy equivalent of 60 milligrams of TNT.
Experiments on fusion in hypervelocity projectiles dates back to 1980.
This approach has been demonstrated commercially by the startup company
First Light Fusion.
Subsequent non-signatory nuclear tests
Three countries have tested nuclear weapons since the CTBT opened for signature in 1996, India, Pakistan, and North Korea, all non-signatories. India and Pakistan both carried out two sets of tests in 1998. North Korea carried out six announced tests, one each in 2006, 2009, 2013, two in 2016 and one in 2017. All six North Korean tests were picked up by the International Monitoring System set up by the Comprehensive Nuclear-Test-Ban Treaty Organization Preparatory Commission. A North Korean test is believed to have taken place in January 2016, evidenced by an "artificial earthquake" measured as a magnitude 5.1 by the
U.S. Geological Survey. The first successful North Korean hydrogen bomb test supposedly took place in September 2017. It was estimated to have an explosive yield of 120 kilotons.
See also
*
International Day for the Total Elimination of Nuclear Weapons
*
List of weapons of mass destruction treaties
*
Comprehensive Nuclear-Test-Ban Treaty Organization
*
Comprehensive Nuclear-Test-Ban Treaty Organization Preparatory Commission
*
National technical means of verification
*
Nuclear disarmament
Nuclear disarmament is the act of reducing or eliminating nuclear weapons. Its end state can also be a nuclear-weapons-free world, in which nuclear weapons are completely eliminated. The term ''denuclearization'' is also used to describe the pro ...
*
Nuclear-free zone
*
Treaty on the Prohibition of Nuclear Weapons
References
Sources
*
*
*
*
*
*
*
*
*
*
External links
Full text of the treaty
CTBTO Preparatory Commissionnbsp;— official news and information
ABC News, 24 February 2006
*
ttps://www.armscontrol.org/factsheets/ctbtissue.asp Daryl Kimball and Christine Kucia, Arms Control Association, 2002
General John M. Shalikashvili, Special Advisor to the President and the Secretary of State for the Comprehensive Test Ban TreatyChristopher Paine, Senior Researcher with NRDC's Nuclear Program, 1999Obama or McCain Can Finish Journey to Nuclear Test Ban Treatyon the ''Comprehensive Nuclear Test Ban Treaty'' in th
United Nations Audiovisual Library of International Lawtitled ''Nuclear Weapons and International Law'' in th
*
ttps://web.archive.org/web/20110303215535/http://opencrs.com/document/RL33548/ Comprehensive Nuclear-Test-Ban Treaty: Background and Current DevelopmentsCongressional Research Service
The Congressional Research Service (CRS) is a public policy research institute of the United States Congress. Operating within the Library of Congress, it works primarily and directly for members of Congress and their committees and staff on a ...
The Woodrow Wilson Center's Nuclear Proliferation International History Projector NPIHP is a global network of individuals and institutions engaged in the study of international nuclear history through archival documents, oral history interviews and other empirical sources.
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