The Mark 11 nuclear bomb was an American
nuclear bomb
A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission or atomic bomb) or a combination of fission and fusion reactions (thermonuclear weapon), producing a nuclear exp ...
developed from the earlier
Mark 8 nuclear bomb in the mid-1950s. Like the Mark 8, the Mark 11 was an earth-penetrating weapon, also known as a
nuclear bunker buster
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 nuclea ...
bomb.
Description
As with the Mark 8, the Mark 11 was a
gun-type nuclear bomb (see also:
gun-type assembly weapon). It used a fixed large target assembly of
highly enriched uranium
Enriched uranium is a type of uranium in which the percent composition of uranium-235 (written 235U) has been increased through the process of isotope separation. Naturally occurring uranium is composed of three major isotopes: uranium-238 (238 ...
(HEU), a gun-like barrel, and a powder charge and a uranium bullet or projectile fired up the barrel into the target.
The Mark 11 was first produced in 1956, and was in service until 1960. A total of 40 were produced, replacing but not expanding the quantity of Mark 8 bombs. It was in diameter and long, with a weight of .
[Complete List of All U.S. Nuclear Weapons] Yield was reportedly the same as the Mark 8, 25 to 30
kiloton
TNT equivalent is a convention for expressing energy, typically used to describe the energy released in an explosion. A ton of TNT equivalent is a unit of energy defined by convention to be (). It is the approximate energy released in the det ...
s.
Both the Mark 8 and the Mark 11 were compatible with the same fissile material "gun cores", but the Mark 11 had a much more modern external casing designed to penetrate further and more reliably into the ground.
[Specifically, they both used what was listed in a later report as the 991 and 992 "Gun Cores." ] The Mark 8 had a flat nose, much like a torpedo. The Mark 11 nose was a pointed
ogive
An ogive ( ) is the roundly tapered end of a two- or three-dimensional object. Ogive curves and surfaces are used in engineering, architecture, woodworking, and ballistics.
Etymology
The French Orientalist Georges Séraphin Colin gives as ...
shape.
The MK-11 also known as the MK-91 had variable yields by changing the target rings. A major difference over the MK-8 was that the MK-91 had an electric operated actuator as a safety device that would rotate a spline ring to prevent the projectile from being fired into the target rings. The MK-8 had no safety devices. Upon release from the delivery aircraft detonation would occur after the black powder fuzes burned 90-110 seconds. The MK-91 was a deep penetrating weapon in many surface materials. A "PHOEBE" polonium
neutron initiator
A modulated neutron initiator is a neutron source capable of producing a burst of neutrons on activation. It is a crucial part of some nuclear weapons, as its role is to "kick-start" the chain reaction at the optimal moment when the configuration i ...
increased the nuclear detonation efficiency.
See also
*
List of nuclear weapons
This is a list of nuclear weapons listed according to country of origin, and then by type within the states. The United States, Russia, China and India are known to possess a nuclear triad, being capable to deliver nuclear weapons by land, sea a ...
*
Mark 8 nuclear bomb
*
Mark 1 Little Boy nuclear bomb
Citations
Bibliography
Complete list of all US nuclear weapons
{{United States nuclear devices
Cold War aerial bombs of the United States
Gun-type nuclear bombs
Nuclear bombs of the United States
Military equipment introduced in the 1950s