Mark 17 nuclear bomb
Encyclopedia
The Mark 17 and Mark 24
Mark 24 nuclear bomb
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...

were the first mass-produced
Mass production
Mass production is the production of large amounts of standardized products, including and especially on assembly lines...

 hydrogen bombs deployed by the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. The two differed in their "primary" stages. The MK 17/24 bombs were 24 in 8 in (7.52 m) long, 61.4 inches (1.6 m) diameter. They weighed 21 tons. The Mark 17 had a yield in the range of 25 megatons TNT equivalent
TNT equivalent
TNT equivalent is a method of quantifying the energy released in explosions. The ton of TNT is a unit of energy equal to 4.184 gigajoules, which is approximately the amount of energy released in the detonation of one ton of TNT...

. Total production of Mk 17s was 200, and there were 105 Mk 24s produced, all between October 1954 and November 1955.

Design and development originated when Los Alamos National Laboratory
Los Alamos National Laboratory
Los Alamos National Laboratory is a United States Department of Energy national laboratory, managed and operated by Los Alamos National Security , located in Los Alamos, New Mexico...

 proposed that a bomb design using ordinary lithium hydride
Lithium hydride
Lithium hydride is the inorganic compound with the formula LiH. It is a colorless solid, although commercial samples are gray. Characteristic of a salt-like, or ionic, hydride, it has a high melting point and is not soluble in any solvent with which it does not react...

 was possible. The new design was designated TX-17 on February 24, 1953. The TX-17 and 24 were tested as the "Runt" (Castle Romeo
Castle Romeo
Castle Romeo was the code name given to one of the tests in the Operation Castle series of American nuclear tests. It was the first test of the TX-17 thermonuclear weapon , the first deployed U.S...

 shot) device during Operation Castle
Operation Castle
Operation Castle was a United States series of high-energy nuclear tests by Joint Task Force SEVEN at Bikini Atoll beginning in March 1954...

 in 1954. After the successful tests, basic versions of the Mk-17 and 24 were deployed as part of the "Emergency Capability" program. A total of 5 EC 17 and 10 EC 24 bombs were rushed into stockpile between April and October 1954. The EC weapons lacked parachutes to delay the time between release and their detonation, ensuring the delivery aircraft would be destroyed with the target. Other safety features such as In Flight Insertion (IFI) and safe arming and fusing devices were also omitted to ensure a quick thermonuclear capability.

The EC weapons were quickly replaced with MK 17 Mod 0 and Mk-24 Mod 0 bombs in October and November 1954. Those weapons included a 64 feet (19.5 m) parachute to allow the delivery aircraft to escape. With the addition of IFI of the Primary capsule to prevent a nuclear explosion in case of an accident, the weapons were upgraded to the Mod 1 standard. The inclusion of a contact fuse
Contact fuse
A contact fuze, percussion fuze or direct-action fuze is the fuze that is placed in the nose of a bomb or shell so that it will detonate on contact with a hard surface....

 upgraded some bombs to the Mod 2 version, allowing the bombs to be used against "soft" targets (air burst), or buried targets such as command bunkers (contact burst).

Due to the introduction of smaller and lighter weapons such as the Mk 15, as well as the pending retirement of the only aircraft capable of carrying them, the B-36
Convair B-36
The Convair B-36 "Peacemaker" was a strategic bomber built by Convair and operated solely by the United States Air Force from 1949 to 1959. The B-36 was the largest mass-produced piston engine aircraft ever made. It had the longest wingspan of any combat aircraft ever built , although there have...

, the Mk 24s were withdrawn by October 1956, with the Mk-17s withdrawn by August 1957.
The Mk 17 was not the first hydrogen bomb stockpiled by the United States. Five examples of the EC14 "Alarm Clock" were prepared for possible use starting in February 1954. There were also five examples of the EC16 "Jughead" cryogenic bomb, a direct development of the "Mike" device produced, starting in January 1954, before the EC17/24 bombs. The EC14s with drogue chutes became Mk 14 bombs and were the first in the hydrogen bomb in the stockpile starting in October 1954. The EC16s were never in the stockpile and were the first EC weapons eliminated. There was only 1 B-36 converted under Project Bar Room to carry the Jughead.
On May 27, 1957 a Mark 17 was unintentionally jettisoned from a B-36 just south of Albuquerque, NM's Kirtland AFB. The device fell through the closed bomb bay doors of the bomber, which was approaching Kirtland at an altitude of 1,700 feet. The device's conventional explosives destroyed it on impact, leaving a crater 25 ft in diameter and 12 ft deep. Though a chain reaction
Nuclear chain reaction
A nuclear chain reaction occurs when one nuclear reaction causes an average of one or more nuclear reactions, thus leading to a self-propagating number of these reactions. The specific nuclear reaction may be the fission of heavy isotopes or the fusion of light isotopes...

 was impossible, because the plutonium pits were stored separately on the plane, the incident spread radioactive contamination
Radioactive contamination
Radioactive contamination, also called radiological contamination, is radioactive substances on surfaces, or within solids, liquids or gases , where their presence is unintended or undesirable, or the process giving rise to their presence in such places...

 and debris over a mile-wide area. Although the military cleaned up the site in secret, a few fragments of the bomb - some radioactive still - may be found in the area. It is one of more than 30 known "Broken Arrow" incidents involving the accidental loss or destruction of a nuclear weapon.

Surviors

Five MK 17/24 casings are on display to the public:
  • National Atomic Museum
    National Atomic Museum
    ‎The National Museum of Nuclear Science & History is a national repository of nuclear science information chartered by the 102nd United States Congress under Public Law 102-190, and located in Albuquerque, New Mexico. "The mission of the National Atomic Museum is to serve as America's resource for...

     located at Albuquerque, New Mexico
    Albuquerque, New Mexico
    Albuquerque is the largest city in the state of New Mexico, United States. It is the county seat of Bernalillo County and is situated in the central part of the state, straddling the Rio Grande. The city population was 545,852 as of the 2010 Census and ranks as the 32nd-largest city in the U.S. As...

    .
  • The Strategic Air Command
    Strategic Air Command
    The Strategic Air Command was both a Major Command of the United States Air Force and a "specified command" of the United States Department of Defense. SAC was the operational establishment in charge of America's land-based strategic bomber aircraft and land-based intercontinental ballistic...

     Memorial at Naval Air Station Fort Worth Joint Reserve Base at Carswell Field in Fort Worth, Texas
    Fort Worth, Texas
    Fort Worth is the 16th-largest city in the United States of America and the fifth-largest city in the state of Texas. Located in North Central Texas, just southeast of the Texas Panhandle, the city is a cultural gateway into the American West and covers nearly in Tarrant, Parker, Denton, and...

    .
  • The National Museum of the United States Air Force
    National Museum of the United States Air Force
    The National Museum of the United States Air Force is the official museum of the United States Air Force located at Wright-Patterson Air Force Base northeast of Dayton, Ohio. The NMUSAF is the world's largest and oldest military aviation museum with more than 360 aircraft and missiles on display...

     in Dayton, Ohio
    Dayton, Ohio
    Dayton is the 6th largest city in the U.S. state of Ohio and the county seat of Montgomery County, the fifth most populous county in the state. The population was 141,527 at the 2010 census. The Dayton Metropolitan Statistical Area had a population of 841,502 in the 2010 census...

     has a Mk 17/24 casing on display in its Cold War Hanger.
  • The Strategic Air and Space Museum
    Strategic Air and Space Museum
    The Strategic Air and Space Museum is a museum focusing on United States Air Force military aircraft and nuclear missiles located near Ashland, Nebraska, along Interstate 80 southwest of Omaha, Nebraska. The objective of the museum is to preserve and display historic aircraft, missile, and space...

     in Ashland, Nebraska
    Ashland, Nebraska
    Ashland is a city in Saunders County, Nebraska, United States. The population was 2,262 at the 2000 census.- History :Ashland is located at the site of a low-water limestone ledge along the bottom of Salt Creek, an otherwise mud-bottomed stream that was a formidable obstacle for wagon trains on the...

    .
  • Castle Air Museum, Atwater, Ca
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