A nuclear bunker buster, also known as an earth-penetrating weapon (EPW), is the nuclear equivalent of the conventional bunker buster. The non-nuclear component of the weapon is designed to penetrate soil, rock, or concrete to deliver a nuclear warhead to an underground target. These weapons would be used to destroy hardened, underground military bunkers or other below-ground facilities. An underground explosion releases a larger fraction of its energy into the ground, compared to a surface burst or air burst explosion at or above the surface, and so can destroy an underground target using a lower explosive yield. This in turn could lead to a reduced amount of radioactive fallout. However, it is unlikely that the explosion would be completely contained underground. As a result, significant amounts of rock and soil would be rendered radioactive and lofted as dust or vapor into the atmosphere, generating significant fallout.
Nuclear weapon designs are physical, chemical, and engineering arrangements that cause the physics package of a nuclear weapon to detonate. There are three existing basic design types:
Yellow Sun was the first British operational high-yield strategic nuclear weapon warhead. The name refers only to the outer casing; the warhead was known as "Green Grass" in Yellow Sun Mk.1 and "Red Snow" in Yellow Sun Mk.2.
Red Snow was a British thermonuclear weapon, based on the US W28 design used in the B28 thermonuclear bomb and AGM-28 Hound Dog missile. The US W28 had yields of 70, 350, 1,100 and 1,450 kilotonnes of TNT and while Red Snow yields are still classified, declassified British documents indicate the existence of "kiloton Red Snow" and "megaton Red Snow" variants of the weapon, suggesting similar yield options, while other sources have suggested a yield of approximately 1 megatonne of TNT (4.2 PJ).
The B83 is a variable-yield thermonuclear gravity bomb developed by the United 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 the B53. It was designed by Lawrence Livermore National Laboratory.
Operation Hardtack I was a series of 35 nuclear tests conducted by the United States from April 28 to August 18 in 1958 at the Pacific Proving Grounds. At the time of testing, the Operation Hardtack I test series included more nuclear detonations than the total of prior nuclear explosions in the Pacific Ocean. These tests followed the Project 58/58A series, which occurred from 1957 December 6 to 1958, March 14, and preceded the Operation Argus series, which took place in 1958 from August 27 to September 6.
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 B-41 was a thermonuclear weapon deployed by the United States Strategic Air Command in the early 1960s. It was the most powerful nuclear bomb ever developed by the United States, with a maximum yield of 25 megatons of TNT. A top secret document, states “The US has stockpiled bombs of 9 MT and 23 MT...” which would likely be referring to the B-41's actual yield(s). The B-41 was the only three-stage thermonuclear weapon fielded by the U.S.
Castle Yankee was the code name given to one of the tests in the Operation Castle series of American tests of thermonuclear bombs. It was originally intended as a test of a TX-16/EC-16 Jughead bomb, but the design became obsolete after the Castle Bravo test was successful. The test device was replaced with a TX-24/EC-24 Runt II bomb which was detonated on May 5, 1954, at Bikini Atoll. It released energy equivalent to 13.5 megatons of TNT, the second-largest yield ever in a U.S. fusion weapon test.
Castle Romeo was the code name given to one of the tests in the Operation Castle series of U.S. nuclear tests. It was the first test of the TX-17 thermonuclear weapon, the first deployed thermonuclear bomb.
The W47 was an American thermonuclear warhead used on the Polaris A-1 sub-launched ballistic missile system. Various models were in service from 1960 through the end of 1974. The warhead was developed by the Lawrence Radiation Laboratory between 1957 and 1960.
The Mark 39 nuclear bomb and W39 nuclear warhead were versions of an American thermonuclear weapon, which were in service from 1957 to 1966.
The Mark 18 nuclear bomb, also known as the SOB or Super Oralloy Bomb, was an American nuclear bomb design which was the highest yield fission bomb produced by the US. The Mark 18 had a design yield of 500 kilotons. Nuclear weapon designer Ted Taylor was the lead designer for the Mark 18.
The Mark 24 nuclear bomb was an American thermonuclear bomb design, based on the third American thermonuclear bomb test, Castle Yankee. The Mark 24 bomb was tied as the largest weight and size nuclear bomb ever deployed by the United States, with the same size and weight as the Mark 17 nuclear bomb which used a very similar design concept but unenriched Lithium.
The Mark 15 nuclear bomb, or Mk-15, was a 1950s American thermonuclear bomb, the first relatively lightweight thermonuclear bomb created by the United States.
Orange Herald was a British nuclear weapon, tested on 31 May 1957. At the time it was reported as an H-bomb, although in fact it was a large boosted fission weapon and remains to date, the largest fission device ever detonated.
The UUM-44 SUBROC was a type of submarine-launched rocket deployed by the United States Navy as an anti-submarine weapon. It carried a 250 kiloton thermonuclear warhead configured as a nuclear depth bomb.
The Mark 13 nuclear bomb and its variant, the W-13 nuclear warhead for Redstone BM and Snark CM, were experimental nuclear weapons developed by the United States from 1951 to 1954. The Mark 13 design was based on the earlier Mark 6 nuclear bomb design, which was in turn based on the Mark 4 nuclear bomb and the Mark 3 nuclear bomb used at the end of World War II.
The Mark 21 nuclear bomb was a United States thermonuclear gravity bomb first produced in 1955. It was based on the TX 21 "Shrimp" prototype that had been detonated during the Castle Bravo test in March 1954. While most of the Operation Castle tests were intended to evaluate weapons intended for immediate stockpile, or which were already available for use as part of the Emergency Capability Program, Castle Bravo was intended to test a design which would drastically reduce the size and costs of the first generation of air-droppable atomic weapons.
