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| B83 | |
|---|---|
 B83 with unclassified components at front | |
| Type | Unguided bomb |
| Service history | |
| In service | 1983–present |
| Used by | United States |
| Production history | |
| Designer | Lawrence Livermore National Laboratory |
| No. built | 650 |
| Specifications | |
| Mass | 2,400 pounds (1,100 kg) |
| Length | 12 feet (3.7 m) |
| Diameter | 18 inches (46 cm) |
| Blast yield | Up to 1.2 megatonnes of TNT (5.0 PJ)[verification needed] |
TheB83 is avariable-yieldthermonucleargravity bomb developed by theUnited States in the late 1970s that entered service in 1983. With a maximum yield of 1.2 megatonnes of TNT (5.0 PJ), it has been the most powerful nuclear weapon in the United States nuclear arsenal since October 25, 2011 after retirement of theB53.[1][2] It was designed byLawrence Livermore National Laboratory.[3]
The B83 was based partly on the earlierB77 program, which was terminated because of cost overruns. The B77 was designed with an active altitude control and lifting parachute system for supersonic low-altitude delivery from theB-1A bomber. Likely B77 nuclear component test firings were attributed to theOperation Anvil series in 1975 and 1976, specifically the "Cheese" test shots in Anvil:[3]
The B83 nuclear components have been attributed as the same as the earlier B77.
The B83 replaced several earlier weapons, including theB28,B43, and, to some extent, the ultra-high-yieldB53. It was the first U.S. nuclear weapon designed from the start to avoid accidental detonation, with the use of"insensitive explosives" in the trigger lens system. Its layout is similar to that of the smallerB61, with thewarhead mounted in the forward part of the weapon to make the bomb nose-heavy. It was intended for high-speed carriage (up toMach 2.0) and delivery at high or low altitude. For the latter role, it is equipped with a parachute retardation system, with a 46-foot (14 m)Kevlarribbon parachute capable of rapid deceleration. It can be employed in free-fall, retarded, contact, andlaydown modes, forair-burst orground-burst detonation. Security features include next-generationpermissive action link (PAL) and a command disablement system (CDS), rendering the weapon tactically useless without a nuclear yield.[3]
The B83 was tested in theGrenadier Tierra nuclear weapon test on 15 December 1984. The test had a reduced yield of 80 kilotonnes due to theThreshold Test Ban Treaty.[3]
With the dismantling of the last B53 bomb in 2011, the B83 became the highest-yield nuclear weapon in the U.S. arsenal.[4] In 2022, theBiden administration announced plans to retire the B83.[5] Once the B83 is retired, the W88 nuclear warhead, deployed on theTrident D5LE missile, will become the most powerful nuclear weapon of the United States, with a yield of 455 kilotonnes.[6] TheB61-13 is planned to replace the B83. Although its yield is lower at 360kilotonnes of TNT (1,500 TJ), it incorporates guidance features of the B61-12 for better accuracy while being more powerful than that version to strike harder and large-area targets.[7]
The bomb is 12 feet (3.7 m) long, with a diameter of 18 inches (460 mm). The actual nuclear explosive package, judging from published drawings[citation needed], occupies some 3 to 4 ft (0.91 to 1.22 m) in the forward part of the bomb case. The bomb weighs approximately 2,400 pounds (1,100 kg).[8] The location of the lifting lugs shows that the greater part of the total mass is contained in the nuclear explosive.
The bomb has avariable yield: the destructive power is adjustable from somewhere in the lowkiloton range up to a maximum of 1.2 megatonnes of TNT (5.0 PJ), some 80 times the explosive power of thebomb dropped on Hiroshima. The weapon is protected by aCategory "D"Permissive Action Link (PAL) that prevents the enabling or detonation of the weapon without proper authorization.[9][10]
About 650 B83s were built, and the weapon remains in service as part of the United States "Enduring Stockpile".[3]
The following aircraft are certified for carrying the B83 bomb:[citation needed]
Nuclear capability has been removed from the B-1B, mostly attributed toSTART I &START II,[14][15] and the B-52 no longer carries gravity nuclear bombs.[13]
The B83 is one of the weapons considered for use in the "Nuclear Bunker Buster" project, which for a time was known as theRobust Nuclear Earth Penetrator, or RNEP. While most efforts have focused on the smallerB61-11 nuclear bomb,Los Alamos National Laboratory was also analyzing the use of the B83 in this role.
Thephysics package contained within the B83 has been studied for use inasteroid impact avoidance strategies against any seriously threateningnear earth asteroids. Six such warheads, configured for the maximum 1.2 megatonnes of TNT (5.0 PJ), would be deployed by maneuvering space vehicles to "knock" an asteroid off course, should it pose a risk to the Earth.[16]
After the B83 is retired, the next most powerful weapon in the U.S. arsenal will be the W88 SLBM warhead, which has an explosive yield oft 455kt (sic)
