B53 nuclear bomb - Wikipedia B53 nuclear bomb B53 Type Thermonuclear weapon Place of origin United States Service history In service 1962 -- 1997 Production history Designer LANL Designed 1958 -- 1961 Manufacturer Atomic Energy Commission Produced 1961 -- 1965 No. built About 340 Specifications Weight 8,850 lb ( 4,010 kg ) Length 12 ft 4 in ( 3.76 m ) Diameter 50 in ( 4.2 ft ; 1.3 m ) Filling Fission : 100 % oralloy Fusion : Lithium - 6 and deuteride Blast yield 9 megatons The Mk / B53 was a high - yield bunker buster thermonuclear weapon developed by the United States during the Cold War. Deployed on Strategic Air Command bombers, the B53, with a yield of 9 megatons, was the most powerful weapon in the U.S. nuclear arsenal after the last B41 nuclear bombs were retired in 1976. The B53 was the basis of the W - 53 warhead carried by the Titan II Missile, which was decommissioned in 1987. Although not in active service for many years before 2010, fifty B53s were retained during that time as part of the `` hedge '' portion of the Enduring Stockpile until its complete dismantling in 2011. The last B53 was disassembled on 25 October 2011, a year ahead of schedule. With its retirement, the largest bomb currently in service in the U.S. nuclear arsenal is the B83, with a maximum yield of 1.2 megatons. The B53 was replaced in the bunker - busting role by a variant of the two - stage B61 nuclear bomb. Contents 1 History 2 Specifications 3 Role 4 W53 5 Effects 6 Artifacts 7 Notes 8 Bibliography 9 External links History Hardtack Oak nuclear weapon test. Development of the weapon began in 1955 by Los Alamos National Laboratory, based on the earlier Mk 21 and Mk 46 weapons. In March 1958 the Strategic Air Command issued a request for a new Class C ( less than five tons, megaton - range ) bomb to replace the earlier Mk 41. A revised version of the Mk 46 became the TX - 53 in 1959. The development TX - 53 warhead was apparently never tested, although an experimental TX - 46 predecessor design was detonated 28 June 1958 as Hardtack Oak, which detonated at a yield of 8.9 Megatons. The Mk 53 entered production in 1962 and was built through June 1965. About 340 bombs were built. It entered service aboard B - 47 Stratojet, B - 52G Stratofortress, and B - 58 Hustler bomber aircraft in the mid-1960s. From 1968 it was redesignated B53. Some early versions of the bomb were dismantled beginning in 1967. About 50 bomb and 54 Titan warhead versions were in service through 1980. After the Titan II program ended, the remaining W - 53s were retired in the late 1980s. The B53 was also intended to be retired in the 1980s, but 50 units remained in the active stockpile until the deployment of the B61 - 11 in 1997. At that point the obsolete B53s were slated for immediate disassembly ; however, the process of disassembling the units was greatly hampered by safety concerns as well as a lack of resources. In 2010 authorization was given to disassemble the 50 bombs at the Pantex plant in Texas. The process of dismantling the last remaining B53 bomb in the stockpile was completed in 2011. Specifications The B53 was 12 feet 4 inches ( 3.76 m ) long with a diameter of 50 inches ( 4.17 ft ; 1.27 m ). It weighed 8,850 pounds ( 4,010 kg ), including the W53 warhead, the 800 - to - 900 lb ( 360 - to - 410 kg ) parachute system and the honeycomb aluminum nose cone to enable the bomb to survive laydown delivery. It had five parachutes : one 5 - foot ( 1.52 m ) pilot chute, one 16 - foot ( 4.88 m ) extractor chute, and three 48 - foot ( 14.63 m ) main chutes. Chute deployment depends on delivery mode, with the main chutes used only for laydown delivery. For free - fall delivery, the entire system was jettisoned. The W53 warhead of the B53 used oralloy ( highly enriched uranium ) instead of plutonium for fission, with a mix of lithium - 6 deuteride fuel for fusion. The explosive lens comprised a mixture of RDX and TNT, which was not insensitive. Two variants were made : the B53 - Y1, a `` dirty '' weapon using a U-238 - encased secondary, and the B53 - Y2 `` clean '' version with a non-fissile ( lead or tungsten ) secondary casing. Explosive yield was approximately nine megatons. Role It was intended as a bunker buster weapon, using a surface blast after laydown deployment to transmit a shock wave through the earth to collapse its target. Attacks against the Soviet deep underground leadership shelters in the Chekhov / Sharapovo area south of Moscow envisaged multiple B53 / W53 exploding at ground level. It has since been supplanted in such roles by the earth - penetrating B61 Mod 11, a bomb that penetrates the surface to deliver much more of its explosive energy into the ground, and therefore needs a much smaller yield to produce the same effects. The B53 was intended to be retired in the 1980s, but 50 units remained in the active stockpile until the deployment of the B61 - 11 in 1997. At that point the obsolete B53s were slated for immediate disassembly ; however, the process of disassembling the units was greatly hampered by safety concerns as well as a lack of resources. The last remaining B53 bomb began the disassembly processes on Tuesday, 25 October 2011 at the Energy Department 's Pantex Plant. An April 2014 GAO report notes that the NNSA is retaining canned subassemblies ( CSAs ) `` associated with a certain warhead indicated as excess in the 2012 Production and Planning Directive are being retained in an indeterminate state pending a senior - level government evaluation of their use in planetary defense against earthbound asteroids. '' In its FY2015 budget request, the NNSA noted that the B53 component disassembly was `` delayed '', leading some observers to conclude they might be the warhead CSAs being retained for potential planetary defense purposes. W53 W53 physics package The W53 warhead of the Titan II ICBM used the same physics package as the B53, without the air drop - specific components like the parachute system and crushable structures in the nose and sides needed for lay - down delivery, reducing its mass to about 6,200 lb ( 2,800 kg ). The 8,140 - pound ( 3,690 kg ) Mark - 6 re-entry vehicle containing the W53 warhead was about 123 inches ( 10.3 ft ; 3.1 m ) long, 7.5 feet ( 2.3 m ) in diameter and was mounted atop a spacer which was 8.3 feet ( 2.5 m ) in diameter at the missile interface ( compared to the missile 's core diameter of 10 feet ( 3.0 m ) ). With a yield of 9 megatons, it was the highest yield warhead ever deployed on a US missile. About 65 W53 warheads were constructed between December 1962 and December 1963. On 19 September 1980 a fuel leak caused a Titan II to explode within its silo in Arkansas, throwing the W53 warhead some distance away. Due to the safety measures built into the weapon, it did not explode or release any radioactive material. 52 active missiles were deployed in silos prior to the beginning of the retirement program in October 1982. With the retirement of the Titan fleet, disassembly of the W53 warheads was completed by about 1988. Effects B53 on display at the Atomic Testing Museum Assuming a detonation at optimum height, a 9 megaton blast would result in a fireball with an approximate 2.9 to 3.4 mi ( 4.7 to 5.5 km ) diameter. The radiated heat would be sufficient to cause lethal burns to any unprotected person within a 20 - mile ( 32 km ) radius ( 1,250 sq mi or 3,200 km ). Blast effects would be sufficient to collapse most residential and industrial structures within a 9 mi ( 14 km ) radius ( 254 sq mi or 660 km ) ; within 3.65 mi ( 5.87 km ) ( 42 sq mi or 110 km ) virtually all above - ground structures would be destroyed and blast effects would inflict near 100 % fatalities. Within 2.25 mi ( 3.62 km ) a 500 rem dose of ionizing radiation would be received by the average person, sufficient to cause a 50 % to 90 % casualty rate independent of thermal or blast effects at this distance. Artifacts B53 on display in the free introduction exhibit room at the Atomic Testing Museum, Las Vegas, Nevada B53 on display at the Wings Over the Rockies Air and Space Museum at the former Lowry AFB, Denver, Colorado Mark 53 casing is on display in the Cold War Gallery at the National Museum of the United States Air Force at Wright - Patterson AFB in Dayton, Ohio B53 casing in display yard of The National Museum of Nuclear Science & History, adjacent to Kirtland AFB in Albuquerque, New Mexico W - 53 on display in the visitors center of the Titan Missile Museum near Tucson, Arizona Notes ^ Jump up to : Cochran 1989, p. 58 ^ Jump up to : Hansen 1988, pp. 162 -- 163 Jump up ^ `` Hedge stockpile '' : fully operational, but kept in storage ; available within minutes or hours ; not connected to delivery systems, but delivery systems are available ( i.e. missile and bomb stockpiles kept at various Air Force bases ) Jump up ^ Blaney, Betsy ( 25 October 2011 ). `` US 's most powerful nuclear bomb being dismantled ''. The Associated Press. Retrieved 25 October 2011. ^ Jump up to : Ackerman, Spencer ( 23 October 2011 ). `` Last Nuclear ' Monster Weapon ' Gets Dismantled ''. Wired. Retrieved 23 October 2011. Jump up ^ Betsy, Blaney ( 25 October 2011 ). `` Most powerful US nuclear bomb dismantled ''. MSNBC. Retrieved 26 October 2011. ^ Jump up to : Johnston, William Robert ( 6 April 2009 ). `` Multimegaton Weapons : The Largest Nuclear Weapons ''. Retrieved 27 October 2011. ^ Jump up to : Walter Pincus ( 19 October 2010 ). `` The Story Of The B - 53 ' Bunker Buster ' Offers A Lesson In Managing Nuclear Weapons ''. The Washington Post. p. 13. Retrieved 19 October 2010. Jump up ^ https://nnsa.energy.gov/mediaroom/pressreleases/b53dismantle102511 Jump up ^ The Editors of the National Catholic Reporter ( 21 March 2013 ). Best Catholic Spirituality Writing 2012 : 30 Inspiring Essays from the National Catholic Reporter. eBooks2go. pp. 8 --. ISBN 978 - 1 - 61813 - 984 - 9. Jump up ^ `` '' Actions Needed by NNSA to Clarify Dismantlement Performance Goal ``, Report to the Subcommittee on Energy and Water Development, Committee on Appropriations, U.S. Senate, United States Government Accountability Office, '' ( PDF ). April 2014. Retrieved 4 August 2014. Jump up ^ `` Department of Energy FY 2015 Congressional Budget Request for the National Nuclear Security Administration '' ( PDF ). March 2014. Retrieved 4 August 2014. ^ Jump up to : Cochran 1989, p. 59 Jump up ^ `` Titan II at Little Rock AFB ''. The Military Standard. Retrieved 27 October 2011. Jump up ^ Walker, John ( June 2005 ). `` Nuclear Bomb Effects Computer ''. Fourmilab. Retrieved 2009 - 11 - 22. Jump up ^ Wellerstein, Alex ( 2012 -- 2014 ). `` NukeMap v2. 42 ''. NukeMap. Retrieved 2014 - 07 - 28. Bibliography Cochran, Thomas B. ( 1989 ). `` US Nuclear Stockpile ''. Nuclear Weapons Databook : United States Nuclear Forces and Capabilities ( PDF ). 1. Ballinger Pub Co. pp. 58 -- 59. ISBN 978 - 0 - 88730 - 043 - 1. Retrieved 26 October 2011. Hansen, Chuck ( 1988 ). US Nuclear Weapons : The Secret History. Arlington, Texas : Aerofax. ISBN 978 - 0 - 517 - 56740 - 1. External links Wikimedia Commons has media related to B53 nuclear bomb. Wikimedia Commons has media related to W53 warheads. The B - 53 ( Mk - 53 ) Bomb United States nuclear devices Fission World War II bombs Little Boy Thin Man Fat Man Post-war bombs Mark III Mark 4 Mark 5 Mark 6 Mark 7 Mark 8 Mark 10 Mark 11 Mark 12 Mark 13 Mark 18 Mark 20 Primaries Swan Python Robin Tsetse Kinglet Post-war warheads W4 W5 W7 W8 W9 W12 W13 W19 W23 W25 W44 W45 W48 W74 W79 W82 Atomic demolition munitions ( mines ) T - 4 SADM TADM MADM Boosted fission Warheads W30 W31 W33 W34 W40 W54 W72 Thermonuclear Bombs Mark 14 Mark 15 TX - 16 Mark 17 Mark 21 TX - 22 Mark 24 Mark 26 Mark 27 B28 Mark 36 Mark 39 B41 B43 TX - 46 B53 B57 B61 B77 B83 B90 Depth bombs Mark 90 Mk 101 B57 Warheads W15 W27 W28 TX - 29 XW - 35 W38 W39 W47 W49 W50 W52 W53 W55 W56 W58 W59 W62 W67 W68 W69 W70 W71 W73 W76 W78 W80 W81 W84 W85 W86 W87 W88 W89 W91 RRW Enhanced radiation warheads W66 W70 Mod 3 W79 Mod 0 W82 Mod 0 Retrieved from `` https://en.wikipedia.org/w/index.php?title=B53_nuclear_bomb&oldid=801587505 '' Categories : Cold War aerial bombs of the United States Nuclear bombs of the United States Hidden categories : Use American English from July 2014 All Wikipedia articles written in American English Use dmy dates from October 2011 Pages using deprecated image syntax All articles with unsourced statements Articles with unsourced statements from October 2011 Commons category with local link different than on Wikidata Talk Contents About Wikipedia Čeština Deutsch Français 한국어 Italiano 日本 語 Polski Português Русский Slovenčina Suomi Edit links This page was last edited on 20 September 2017, at 16 : 09. 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Question: what is the largest nuclear bomb america has
Answer: Mk/B53