There are currently eight states that have successfully detonated nuclear weapons. Five are considered to be "nuclear-weapon states" (NWS) under the terms of the Nuclear Non-Proliferation Treaty (NPT). In order of acquisition of nuclear weapons these are: the United States, Russia (successor state to the Soviet Union), the United Kingdom, France, and China. Nations that are known or believed to possess nuclear weapons are sometimes referred to as the nuclear club.
Since the NPT entered into force in 1970, three states that were not parties to the Treaty have conducted nuclear tests, namely India, Pakistan, and North Korea. North Korea had been a party to the NPT but withdrew in 2003. Israel is also widely believed to have nuclear weapons, though it has refused to confirm or deny this, and is not known to have conducted a nuclear test.
South Africa has the unique status of a nation that developed nuclear weapons but has since disassembled its arsenal before joining the NPT.
United States
The United States developed the first atomic weapons during World War II in co-operation with the United Kingdom and Canada as part of the Manhattan Project, out of the fear that Nazi Germany would develop them first. It tested the first nuclear weapon in 1945 ("Trinity"), and remains the only country to have used nuclear weapons against another nation, during the atomic bombings of Hiroshima and Nagasaki. It was the first nation to develop the hydrogen bomb, testing an experimental version in 1952 ("Ivy Mike") and a deployable weapon in 1954 ("Castle Bravo"). Throughout the Cold War it continued to modernize and enlarge its nuclear arsenal, but from 1992 on has been involved primarily in a program of Stockpile stewardship. At its Cold War height, the US nuclear arsenal is estimated to have contained over 32,000 warheads (in 1966).
| Nuclear program start date | 21 October 1939 |
|---|---|
| First nuclear weapon test | 16 July 1945 |
| First fusion weapon test | 1 November 1952 |
| Last nuclear test | 23 September 1992 |
| Largest yield test | 15 Mt (1 March 1954) |
| Total tests | 1,054 detonations |
| Peak stockpile | 31,255 warheads (1967) |
| Current stockpile | 5,113 total |
| Maximum missile range | 13,000 km (8,100 mi) (land) 12,000 km (7,500 mi) (sub) |
| NPT signatory | Yes (1968, one of five recognized powers) |
(Trinity explosion, 0.016 seconds after detonation)
(The mushroom cloud from the Mike shot)
Russian Federation
The Soviet Union tested its first nuclear weapon ("Joe-1") in 1949, in a crash project developed partially with espionage obtained during and after World War II (see: Soviet atomic bomb project). The USSR was the second nation to have developed and tested a nuclear weapon. The direct motivation for their weapons development was to achieve a balance of power during the Cold War. It tested its first megaton-range hydrogen bomb ("RDS-37") in 1955. The Soviet Union also tested the most powerful explosive ever detonated by humans, ("Tsar Bomba"), with a theoretical yield of 100 megatons, intentionally reduced to 50 when detonated. After its dissolution in 1991, the Soviet weapons entered officially into the possession of the Russian Federation. At its maximum, the Soviet nuclear arsenal is estimated to have contained some 45,000 warheads (in 1988).
| First nuclear weapon test | August 29, 1949 |
|---|---|
| First fusion weapon test | August 12, 1953 |
| Last nuclear test | 24 October 1990 |
| Largest yield test | 50 Mt (210 PJ) (30 October 1961) |
| Total tests | 715 detonations |
| Peak stockpile | 45,000 warheads (1986) |
| Current stockpile | 12,000 total (2010 est.) |
| Maximum missile range | Intercontinental up to 16.000 kilometers |
| NPT signatory | Yes (1968, one of five recognized powers) |
(First Soviet Bomb RDS-1)
(Tsar Bomba mushroom cloud seen from a distance of 160 km)
United Kingdom
The United Kingdom tested its first nuclear weapon ("Hurricane") in 1952, drawing largely on data gained while collaborating with the United States during the Manhattan Project. The United Kingdom was the third country in the world after the USA and USSR to develop and test a nuclear weapon. Its programme was motivated to have an independent deterrent against the USSR, while also maintaining its status as a great power. It tested its first hydrogen bomb in 1957 (Operation Grapple), making it the third country to do so after the USA and USSR. The UK maintained a fleet of V-bomber strategic bombers and ballistic missile submarines (SSBNs) equipped with nuclear weapons during the Cold War. It currently maintains a fleet of four 'Vanguard' class ballistic missile submarines equipped with Trident II SLBMs. The British government announced a replacement to the current system to take place between 2007-2024.
| Nuclear program start date | 10 April 1940 |
|---|---|
| First nuclear weapon test | 3 October 1952 |
| First fusion weapon test | 15 May 1957 |
| Last nuclear test | 26 November 1991 |
| Largest yield test | 3 Mt (13 PJ) (28 April 1958) |
| Total tests | 45 detonations |
| Peak stockpile | 350 warheads (1970s) |
| Current stockpile | 225 warheads |
| Maximum missile range | 13,000 km (7,000 nmi or 8,100 mi) |
| NPT signatory | Yes (1968, one of five recognised powers) |
(Explosion cloud resulting from the Operation Hurricane detonation)
(A Trident missile launched from a Royal Navy Vanguard class ballistic missile submarine)
France
France tested its first nuclear weapon in 1960 ("Gerboise Bleue"), based mostly on its own research. It was motivated by the Suez Crisis diplomatic tension vis-à-vis both the USSR and the Free World allies United States and United Kingdom. It was also relevant to retain great power status, alongside the United Kingdom, during the post-colonial Cold War (see: Force de frappe). France tested its first hydrogen bomb in 1968 ("Opération Canopus"). After the Cold War, France has disarmed 175 warheads with the reduction and modernization of its arsenal that has now evolved to a dual system based on submarine-launched ballistic missiles (SLBMs) and medium-range air-to-surface missiles (Rafale fighter-bombers). However new nuclear weapons are in development and reformed nuclear squadrons were trained during Enduring Freedom operations in Afghanistan. In January 2006, President Jacques Chirac stated a terrorist act or the use of weapons of mass destruction against France would result in a nuclear counterattack.
| First nuclear weapon test | February 13, 1960 |
|---|---|
| First fusion weapon test | August 24, 1968 |
| Last nuclear test | December 28, 1995 |
| Largest yield test | 2.6 Mt (August 24, 1968) |
| Total tests | 210 |
| Current stockpile | N/A (not confirmed) |
| Maximum missile range | >10,000 km (M51 SLBM) |
| NPT signatory | Yes (1992, one of five recognized powers) |
(French nuclear-powered aircraft carrier Charles de Gaulle (right) and the American nuclear-powered carrier USS Enterprise (left), each of which carries nuclear-capable fighter aircraft)
China
China tested its first nuclear weapon device ("596") in 1964 at the Lop Nur test site. The weapon was developed as a deterrent against both the United States and the Soviet Union. China would manage to develop a fission bomb capable of being put onto a nuclear missile only two years after its first detonation. It tested its first hydrogen bomb ("Test No. 6") in 1967, a mere 32 months after testing its first nuclear weapon (the shortest fission-to-fusion development known in history).The country is currently thought to have had a stockpile of around 240 warheads, though because of the limited information available, estimates range from 100 to 400. China is the only NPT nuclear-weapon state to give an unqualified negative security assurance due to its "no first use" policy.
| First nuclear weapon test | October 16, 1964 |
|---|---|
| Last nuclear test | July 29, 1996 |
| Largest yield test | 4 Mt
|
| Total tests | 44 |
| Peak stockpile | 434 |
| Current stockpile | ~400 |
| Maximum missile range | 12,000-15,000 km |
| NPT signatory | Yes (1992, one of five recognized powers) |
(The mock design of the first Chinese bomb)
Pakistan
Pakistan also is not a Party to the Nuclear Non-Proliferation Treaty. Pakistan covertly developed nuclear weapons over many decades, beginning in the late 1970s. Pakistan first delved into nuclear power after the establishment of its first nuclear power plant near Karachi with equipment and materials supplied mainly by western nations in the early 1970s. Pakistani Prime Minister Zulfiqar Ali Bhutto promised in 1965 that if India can build nuclear weapons then Pakistan would too, "even if we have to eat grass." The United States continued to certify that Pakistan did not possess nuclear weapons until 1990, when sanctions were imposed under the Pressler Amendment, requiring a cutoff of U.S. economic and military assistance to Pakistan. In 1998, Pakistan conducted its first six nuclear tests at the Chagai Hills, in response to the five tests conducted by India a few weeks before. Over the years, Pakistan has developed into a crucial nuclear power.
In 2004, the Pakistani metallurgist A.Q. Khan, a key figure in Pakistan's nuclear weapons program, confessed to heading an international black market ring involved in selling nuclear weapons technology. In particular, Khan had been selling gas centrifuge technology to North Korea, Iran, and Libya. Khan denied complicity by the Pakistani government or Army, but this has been called into question by journalists and IAEA officials, and was later contradicted by statements from Khan himself.
| Nuclear program start date | January 20, 1972 |
|---|---|
| First nuclear weapon test | May 28, 1998 (Chagai-I) |
| First fusion weapon test | Unknown |
| Last nuclear test | May 30, 1998 (Chagai-II) |
| Largest yield test | 25-36 kt in 1998 (PAEC claim) |
| Total tests | 6 detonations |
| Peak stockpile | 100-110 warheads (2011 estimate) |
| Current stockpile | 100-110 warheads |
| Maximum missile range | 2,500 km (Shaheen-II) |
| NPT signatory | No |
(The mountain is seen raised above as the chain reaction build up by the devices)
North Korea
North Korea was a Party to the Nuclear Non-Proliferation Treaty, but announced a withdrawal on January 10, 2003, after the United States accused it of having a secret uranium enrichment program and cut off energy assistance under the 1994 Agreed Framework. In February 2005 the North Koreans claimed to possess functional nuclear weapons, though their lack of a test at the time led many experts to doubt the claim. However, in October 2006, North Korea stated that due to growing intimidation by the USA, it would conduct a nuclear test to confirm its nuclear status. North Korea reported a successful nuclear test on October 9, 2006 (see 2006 North Korean nuclear test). Most U.S. intelligence officials believe that North Korea did, in fact, test a nuclear device due to radioactive isotopes detected by U.S. aircraft; however, most agree that the test was probably only partially successful. The yield may have been less than a kiloton, which is much smaller than the first successful tests of other powers; however, boosted fission weapons may have an unboosted yield in this range, which is sufficient to start deuterium-tritium fusion in the boost gas at the center; the fast neutrons from fusion then ensure a full fission yield. North Korea conducted a second, higher yield test on May 25, 2009 (see 2009 North Korean nuclear test).
| Nuclear program start date | 1956 |
|---|---|
| First nuclear weapon test | October 9, 2006 |
| Last nuclear test | May 25, 2009 |
| Largest yield test | 2~6 kt (The yield is disputed. The North-Korean government never announced the exact yield.) |
| Total tests | 2 |
| Current stockpile | 6–8 nuclear weapons (estimated) |
| Maximum missile range | 4,000 km (BM25 Musudan) |
| NPT signatory | Yes, but withdrew in 2003 |
India
India is not a Party to the Nuclear Non-Proliferation Treaty. India tested what it called a "peaceful nuclear explosive" in 1974 (which became known as "Smiling Buddha"). The test was the first test developed after the creation of the NPT, and created new questions about how civilian nuclear technology could be diverted secretly to weapons purposes (dual-use technology). India's secret development caused great concern and anger particularly from nations, such as Canada, that had supplied it nuclear reactors for peaceful and power generating needs. It appears to have been primarily motivated as a general deterrent, as well as an attempt to project India as a regional power.Though India maintained that its nuclear capability was primarily "peaceful", it apparently weaponized two dozen nuclear weapons for delivery by air between 1988 and 1990. But it was not until 1998 that India tested weaponized nuclear warheads ("Operation Shakti"), including a thermonuclear device.In July 2005, U.S. President George W. Bush and Indian Prime Minister Manmohan Singh announced plans to conclude an Indo-US civilian nuclear agreement. This came to fruition through a series of steps that included India’s announced plan to separate its civil and military nuclear programs in March 2006, the passage of the United States-India Peaceful Atomic Energy Cooperation Act by the U.S. Congress in December 2006, the conclusion of a U.S.-India nuclear cooperation agreement in July 2007, approval by the IAEA of an India-specific safeguards agreement, agreement by the Nuclear Suppliers Group to a waiver of export restrictions for India,approval by the U.S. Congress and culminating in the signature of U.S.-India agreement for civil nuclear cooperation in October 2008. The U.S. State Department said it made it "very clear that we will not recognize India as a nuclear-weapon state". The United States is bound by the Hyde Act with India and may cease all cooperation with India if India detonates a nuclear explosive device. The US had further said it is not its intention to assist India in the design, construction or operation of sensitive nuclear technologies through the transfer of dual-use items. In establishing an exemption for India, the Nuclear Suppliers Group reserved the right to consult on any future issues which might trouble it. As of June 2011, India was estimated to have had a stockpile of around 80–100 warheads.
| Nuclear program start date | 1967 |
|---|---|
| First nuclear weapon test | 18 May 1974 (Smiling Buddha) |
| First fusion weapon test | 11 May 1998 (declared) |
| Last nuclear test | 13 May 1998 |
| Largest yield test | 20-60 kt total in Pokhran-II (yield is disputed) |
| Total tests | 6 |
| Peak stockpile | 80–100(2011 est.) |
| Current stockpile | 80–100(2011 est.) |
| Maximum missile range | <2500 km (Agni II) |
| NPT signatory | No |
(Image of Shaft-III named Shakti)
Israel
Israel is not a party to the Nuclear Non-Proliferation Treaty and refuses to officially confirm or deny having a nuclear arsenal, or having developed nuclear weapons, or even having a nuclear weapons program. Israel has pledged not to be the first country to introduce nuclear weapons into the region, but is also pursuing a policy of strategic ambiguity with regard to their possession. This is sometimes called a policy of "nuclear opacity": Israel neither confirms nor denies that it possesses nuclear weapons, in what has been interpreted as an attempt to get the benefits of deterrence with a minimum political cost. In the late 1960s, Israeli Ambassador to the US Yitzhak Rabin informed the United States State Department, that its understanding of "introducing" such weapons meant that they would be tested and publicly declared, while merely possessing the weapons did not constitute "introducing" them. Israel claims that the Negev Nuclear Research Center near Dimona is a research center. However, there is extensive evidence Israel has nuclear weapons or a near-ready nuclear weapons capability. Extensive information about the program in Dimona was also disclosed by technician Mordechai Vanunu in 1986.
According to the Natural Resources Defense Council and the Federation of American Scientists, Israel likely possesses around 75–200 weapons. Imagery analysts can identify weapon bunkers, mobile missile launchers, and launch sites in satellite photographs. Israel may have tested a nuclear weapon along with South Africa in 1979, but this has never been confirmed, and interpretation of the evidence is controversial.
| Nuclear program start date | mid-to-late 1950s |
|---|---|
| First nuclear weapon test | Unknown; possible joint nuclear test with South Africa on September 22, 1979 |
| First fusion weapon test | Unknown |
| Last nuclear test | Unknown |
| Largest yield test | Unknown |
| Total tests | Unknown |
| Peak stockpile | Unknown |
| Current stockpile |
allegedly 75–400 warheads
|
| Maximum missile range | 11,500 km with 1000 kg payload; probably significantly greater with smaller payload (Jericho III) |
| NPT signatory (NO) |
(The Negev Nuclear Research Center as viewed from satellite)