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US's Most Powerful Atomic Bomb, B53 - Dismantled


Being the last of its kind and the US's most powerful, the B53 atomic bomb, has been dismantled in Amarillo Texas.
Experts at Pantex near Amarillo disassembled and removed the uranium Tuesday from the last of the US's largest nuclear conventionally dropped weapons, a Cold War relic known as the B53 nuclear bomb.
The BWXT Pantex plant is America's only nuclear weapons assembly and disassembly facility and is charged with maintaining the safety, security and reliability of the nation’s nuclear weapons stockpile.
The Mk/B-53 was the oldest and highest yield thermonuclear weapon in the U.S. arsenal until 2010. It was one of the most powerful nuclear weapons ever built by the United States with a yield of 9 megatons of TNT (38 PJ).
Although not in active service for many years before 2010, 50 were retained during that time as part of the "Hedge" portion of the Enduring Stockpile until its complete dismantling in 2011, a year ahead of schedule. The B53 was replaced in the bunker-busting role by a variant of the two-stage B61. The B53 was similar to the W-53 warhead used in the Titan II Missile, which was decommissioned in 1987.
The B53 was 12-foot-6-inch (3.81 m) long with a diameter of 50 inches (1.27 m). It weighed 8,850 pounds (4,010 kg), including the 800–900 lb (360–410 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 warhead of the B53 uses oralloy (highly enriched uranium) instead of plutonium for fission, with a mix of lithium-6 deuteride fuel for fusion. The explosive lens is a mixture of RDX and TNT, which is 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.
Development of the weapon began in 1955 by Los Alamos Scientific 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-52 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 a B-53-equipped Titan missile exploded in Arkansas, the remaining Titan warheads were retired. The 50 bombs were retired from service beginning in 1997, but not dismantled. 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 commenced on 25 October 2011 and was completed soon afterwards.
Assuming a detonation at optimum height, a 9 megaton blast would result in a fireball some 4 to 5 kilometers (2.5 to 3 miles) in diameter. The radiated heat would be sufficient to cause lethal burns to any unprotected person within a 28.7 kilometers (17.8 mi) radius (995 square miles (2,580 km2)). Blast effects would be sufficient to collapse most residential and industrial structures within a 14.9-kilometer (9.3 mi) radius (300 square miles (780 km2)); within 5.7 kilometers (3.5 mi) virtually all above-ground structures would be destroyed and blast effects would inflict near 100% fatalities. Within 4.7 kilometers (2.9 mi) 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.
Observing the dismantling, Deputy Secretary of Energy Daniel Poneman stated, it's "a milestone accomplishment" and a step toward our mission to rid the world of nuclear weapons. watched workers take the bomb apart.
In the US arsenal remains the B83 which weighs in at 1.2 megatons compared to the B53 which was 9 megatons.

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Added: Oct-25-2011 Occurred On: Oct-25-2011
By: migueldeagua
In:
World News
Tags: US's Most Powerful Atomic Bomb, B53 - Dismantled, Texas, Pantex
Location: Amarillo, Texas, United States (load item map)
Views: 6395 | Comments: 10 | Votes: 0 | Favorites: 0 | Shared: 48 | Updates: 0 | Times used in channels: 2
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