American nuclear weapons of all types – bombs, warheads, shells, and others – are numbered in the same sequence starting with the Mark 1 and (as of March 2006[update]) ending with the W91 (which was canceled prior to introduction into service). All designs which were formally intended to be weapons at some point received a number designation. Pure test units which were experiments (and not intended to be weapons) are not numbered in this sequence.
Early weapons were very large and could only be used as free fall bombs. These were known by "Mark" designators, like the Mark 4 which was a development of the Fat Man weapon. As weapons became more sophisticated they also became much smaller and lighter, allowing them to be used in many roles. At this time the weapons began to receive designations based on their role; bombs were given the prefix "B", while the same warhead used in other roles, like missiles, would normally be prefixed "W". For instance, the W-53 warhead was also used as the basis for the B53 nuclear bomb. Such examples share the same sequence number.
In other cases, when the modifications are more significant, variants are assigned their own number. An example is the B61 nuclear bomb, which was the parent design for the W80, W81, and W84. There are also examples of out-of-sequence numbering and other prefixes used in special occasions.
This list includes weapons which were developed to the point of being assigned a model number (and in many cases, prototypes were test fired), but which were then canceled prior to introduction into military service. Those models are listed as canceled, along with the year or date of cancellation of their program.
Bombs – designated with Mark ("Mk") numbers until 1968, and with "B" numbers after that. "Test Experimental" bombs designated with "TX".
Mark 1 – "Little Boy" gun-type uranium weapon (used against Hiroshima). (13–18 kilotons, 1945–1950)
Mark 2 – "Thin Man" plutonium gun design—cancelled in 1944
Implosion Mark 2 – Another Manhattan Project plutonium implosion weapon, a hollow pitimplosion design, was also sometimes referred to as Mark 2. Also cancelled 1944.
Mark 3 – "Fat Man" plutonium implosion weapon (used against Nagasaki), effectively the same as the "Gadget" device used in the Trinity nuclear test with minor design differences. (21 kilotons, 1945–1950)
Mark 4 – Post-war "Fat Man" redesign. Bomb designed with weapon characteristics as the foremost criteria. (1949–1953)
Mark 5 – Significantly smaller high efficiency nuclear bomb. (1–120 kilotons, 1952–1963)
Mark 6 – Improved version of Mk-4. (8–160 kilotons, 1951–1962)
Mark 7 – Multi-purpose tactical bomb. (8–61 kilotons, 1952–1967)
Mark 8 – Gun-assembly, HEU weapon designed for penetrating hardened targets. (25–30 kilotons, 1951–1957)
Mark 10 – Improved version of Mk-8 (12–15 kilotons, cancelled May 1952).
Mark 11 – Re-designed Mk-8. Gun-type (8–30 kilotons).
At the peak of its arsenal in 1988, Russia possessed around 45,000 nuclear weapons in its stockpile, roughly 13,000 more than the United States arsenal, the second largest in the world, which peaked in 1966.[2]
RDS-6, also known as RDS-6S, or "sloika" or 'layer cake" gaining about 20% of its yield from fusion. RDS-6 was tested on 12 August 1953. Yield 400 kilotons
RDS-7, a backup for the RDS-6, the RDS-7 was a 500 kiloton all fission bomb comparable to the US Mk-18, development dropped after success of the RDS-6S
RDS-27, 250 kiloton bomb, a 'boosted' fission bomb tested 6 November 1955.
RDS-37, 3 megaton bomb, the first Soviet two-stage hydrogen bomb, tested 22 November 1955
RDS-220Tsar Bomba an extremely large three stage bomb, initially designed as a 100-megaton-bomb, but was scaled down to 50 megatons for testing.
Blue Cat – nuclear warhead a.k.a. Tony - UK version of US W44, a.k.a. Tsetse.
Blue Fox – kiloton range nuclear weapon, later renamed Indigo Hammer - not to be confused with the later Blue Fox radar.
Blue Peacock ten-kiloton nuclear land mine, a.k.a. the "chicken-powered nuclear bomb", originally 'Blue Bunny' It used the Blue Danube physics package.
Blue Rosette – short-case nuclear weapon bomb casing for reconnaissance bomber to spec R156T, including the Avro 730, Handley Page HP.100, English Electric P10, Vickers SP4 and various others.
Blue Slug – nuclear ship-to-ship missile using Sea Slug launcher.
Blue Water – nuclear armed surface to surface missile.
Orange Herald – fusion-boosted fission weapon. It is believed that the fusion boost didn't work, which would make it the most powerful fission bomb ever tested at 720 kt.
Although India's nuclear programme and its details are highly classified, international figures suggest that India possesses about 150 nuclear weapons, with enough weapons-grade plutonium for another 150–200 nuclear weapons (2020 estimate). 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.[6][7][8]
Israel is widely believed to possess a substantial arsenal of nuclear weapons and missiles, estimated at 75–130 and 100–200[9] warheads, but refuses officially to confirm or deny whether it has a nuclear weapon program, leaving the details of any such weapons unclear. Mordechai Vanunu, a former nuclear technician for Israel, confirmed the existence of a nuclear weapons program in 1986.
Unconfirmed rumors have hinted at tactical nuclear artillery shells, light fission bombs and missile warheads, and perhaps thermonuclear missile warheads.[10]
The BBC News Online website published an article[11] on 28 May 2008, which quotes former U.S. President Jimmy Carter as stating that Israel has at least 150 nuclear weapons. The article continues to state that this is the second confirmation of Israel's nuclear capability by a U.S. spokesman following comments from U.S. Defense Secretary Robert Gates at a Senate hearing and had apparently been confirmed a short time later by Israeli Prime Minister Ehud Olmert.[12]
As of June 2019, Pakistan is believed to possess about 160 nuclear weapons. The specifications of its weapon production are not disclosed to the public. The main series for nuclear transportation is Hatf (lit. Target).[13][14]
North Korea claims to possess nuclear weapons, however, the specifications of its systems are not public. It is estimated to have 6–18 low yield nuclear weapons (August 2012 estimate).[15] On 9 October 2006, North Korea achieved its first nuclear detonation.
On 25 May 2009, North Korea conducted a second test of nuclear weapons at the same location as the original test. The test weapon was of the same magnitude as the atomic bombs dropped on Japan in the 2nd World War. At the same time of the test, North Korea tested two short range ballistic missiles. The country tested a 7 kt nuclear weapon on 2 February 2013. On 3 September 2017, North Korea conducted an underground thermonuclear test which had an estimated yield of 100kt to 250kt, according to various sources.
On March 24, 2023, North Korea unveiled the Hwasal-31 화살-31 [ko] tactical nuclear bomb with at least 10 warheads shown, each measuring an estimated 40 to 50 centimeters in diameter and 1 meter in length as reported by the South Korean media. KN-23 and KN-25 ballistic missiles are capable of carrying it.[16][17][18]
South Africa built six or seven gun-type weapons. All constructed weapons were verified by International Atomic Energy Agency and other international observers to have been dismantled, along with the complete weapons program, and their highly enriched uranium was reprocessed back into low enriched form unsuitable for weapons.
^Robert S. Norris and Hans M. Kristensen, "Global nuclear stockpiles, 1945-2006," Bulletin of the Atomic Scientists 62, no. 4 (July/August 2006), 64-66.
CNS Resources on South Africa's Nuclear Weapons Program at the Library of Congress Web Archives (archived 2001-09-27) – indicates that "most international experts conclude that South Africa has completed its nuclear disarmament. South Africa is the first and to date only country to build nuclear weapons and then entirely dismantle its nuclear weapons program."
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