Castle Romeo was the code name given to one of the tests in the

Operation Castle Operation Castle was a United States series of high-yield (high-energy) nuclear tests by Joint Task Force 7 (JTF-7) at Bikini Atoll beginning in March 1954. It followed ''Operation Upshot–Knothole'' and preceded ''Operation Teapot''. Condu ...

series of U.S.

nuclear tests Nuclear weapons tests are experiments carried out to determine nuclear weapons' effectiveness, yield, and explosive capability. Testing nuclear weapons offers practical information about how the weapons function, how detonations are affected by ...

. It was the first test of the TX-17

thermonuclear weapon A thermonuclear weapon, fusion weapon or hydrogen bomb (H bomb) is a second-generation nuclear weapon design. Its greater sophistication affords it vastly greater destructive power than first-generation nuclear bombs, a more compact size, a lo ...

, the first deployed thermonuclear bomb. It was detonated on March 26, 1954, at

Bikini Atoll Bikini Atoll ( or ; Marshallese: , , meaning "coconut place"), sometimes known as Eschscholtz Atoll between the 1800s and 1946 is a coral reef in the Marshall Islands consisting of 23 islands surrounding a central lagoon. After the Seco ...

of the

Marshall Islands The Marshall Islands ( mh, Ṃajeḷ), officially the Republic of the Marshall Islands ( mh, Aolepān Aorōkin Ṃajeḷ),'' () is an independent island country and microstate near the Equator in the Pacific Ocean, slightly west of the Inte ...

, on a barge moored in the middle of the crater from the

Castle Bravo Castle Bravo was the first in a series of high-yield thermonuclear weapon design tests conducted by the United States at Bikini Atoll, Marshall Islands, as part of '' Operation Castle''. Detonated on March 1, 1954, the device was the most powerful ...

test. It was the first such barge-based test, a necessity that had come about because the powerful thermonuclear devices obliterated the small islands following detonation.

Deployment

The tested design became the first air-droppable thermonuclear device, initially the "emergency capability" EC-17, of which only five were made. The first deployable staged radiation implosion Teller-Ulam thermonuclear weapon evolved into the Mark 17, of which 200 were made. Both of those were huge devices, weighing and respectively. As a result, only the

B-36 The Convair B-36 "Peacemaker" is a strategic bomber that was built by Convair and operated by the United States Air Force (USAF) from 1949 to 1959. The B-36 is the largest mass-produced Reciprocating engine, piston-engined aircraft ever built. It ...

was capable of carrying that first generation of thermonuclear bombs. They were also some of the largest yield devices deployed by

Strategic Air Command Strategic Air Command (SAC) was both a United States Department of Defense Specified Command and a United States Air Force (USAF) Major Command responsible for command and control of the strategic bomber and intercontinental ballistic missile ...

— the EC-17 producing around 10 megatonnes (Mt), and the Mk 17 between 11 and 15 Mt. They were all out of service by August 1957.

Design

The ''Runt'' TX-15 device was a weaponized dry

fusion Fusion, or synthesis, is the process of combining two or more distinct entities into a new whole. Fusion may also refer to: Science and technology Physics *Nuclear fusion, multiple atomic nuclei combining to form one or more different atomic nucl ...

bomb, using

lithium deuteride Lithium hydride is an inorganic compound with the formula Li H. This alkali metal hydride is a colorless solid, although commercial samples are grey. Characteristic of a salt-like (ionic) hydride, it has a high melting point, and it is not solub ...

fuel for the fusion stage of a staged fusion bomb, unlike the

cryogenic In physics, cryogenics is the production and behaviour of materials at very low temperatures. The 13th IIR International Congress of Refrigeration (held in Washington DC in 1971) endorsed a universal definition of “cryogenics” and “cr ...

liquid

deuterium Deuterium (or hydrogen-2, symbol or deuterium, also known as heavy hydrogen) is one of two stable isotopes of hydrogen (the other being protium, or hydrogen-1). The nucleus of a deuterium atom, called a deuteron, contains one proton and one ...

of the first-generation

Ivy Mike Ivy Mike was the codename given to the first full-scale test of a thermonuclear device, in which part of the explosive yield comes from nuclear fusion. Ivy Mike was detonated on November 1, 1952, by the United States on the island of Elugelab ...

fusion device. Similar to the ''Shrimp'' TX-21 device tested before in the

test, it differed from that device in using lithium deuteride derived from natural

lithium Lithium (from el, λίθος, lithos, lit=stone) is a chemical element with the symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard conditions, it is the least dense metal and the least dense soli ...

(a mixture of 7.5%

lithium-6 Naturally occurring lithium (3Li) is composed of two stable isotopes, lithium-6 and lithium-7, with the latter being far more abundant on Earth. Both of the natural isotopes have an unexpectedly low nuclear binding energy per nucleon ( for l ...

and 92.5%

lithium-7 Naturally occurring lithium (3Li) is composed of two stable isotopes, lithium-6 and lithium-7, with the latter being far more abundant on Earth. Both of the natural isotopes have an unexpectedly low nuclear binding energy per nucleon ( for lit ...

isotope Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers ( mass num ...

s) as the source of the tritium and deuterium fusion fuels, as opposed to the relative high enrichment level of lithium (approximately 40% lithium-6) deuteride used in Bravo.

Yield

Like the Bravo test, it produced far more than its predicted yield, and for the same reason — an unexpected participation of the common lithium-7 isotope in fusion reactions. Although it had been predicted to produce a yield of 4

megatons TNT equivalent is a convention for expressing energy, typically used to describe the energy released in an explosion. The is a unit of energy defined by that convention to be , which is the approximate energy released in the detonation of a ...

with a range of 1.5 to 7 megatons (before the results of the Bravo test caused an upgrade in the estimates, it had originally been estimated to produce 3–5 megatons), it actually produced a yield of 11 megatons, the third-largest test ever conducted by the U.S. Like the Ivy Mike and Castle Bravo tests, a large percentage of the yield was produced by fast fission of the natural

uranium Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weak ...

"tamper"; 7 megatons of the yield were from this source.

Fireball in popular culture

One particular image of the Castle Romeo fireball has been one of the most highly reprinted images of a nuclear explosion. It often serves as a stand-in for nuclear weapons in general for news stories, book covers, magazine articles, etc., likely because of its threatening appearance and extreme red, orange, and yellow hues. The fact that the explosion is of a U.S. megaton-range weapon has not prevented it from being used to represent the arsenals of other states or weapons of far lower yields in many cases, which would have a very different appearance. One prominent usage is as the backdrop for heavy metal band

Megadeth Megadeth is an American thrash metal band formed in Los Angeles in 1983 by vocalist/guitarist Dave Mustaine. Known for their technically complex guitar work and musicianship, Megadeth is one of the "big four" of American thrash metal along wit ...

's greatest hits compilation '' Greatest Hits: Back to the Start''. The image of Castle Romeo was also used on the cover of the New York hardcore music pioneers

Cro-Mags Cro-Mags are an American hardcore punk band from New York City. The band, which has a strong cult following, has released six studio albums, with the first two considered the most influential. With a Hare Krishna background, they were among th ...

debut album ''

The Age of Quarrel ''The Age of Quarrel'' is the first album by the New York hardcore band Cro-Mags. It was released on then-independent Profile Records in September 1986. It was subsequently re-released by Another Planet in 1994, along with the band's second alb ...

''. It is also featured on the title screen of

Team17 Team17 Group plc is a British video game developer and publisher based in Wakefield, England. The venture was created in December 1990 through the merger of British publisher 17-Bit Software and Swedish developer Team 7. At the time, the two co ...

's turn-based artillery game '' Worms Armageddon''. The Castle Romeo photos are sometimes confused with that of

. The two nuclear blasts looked very similar, and they were both conducted in the same location, but much of Bravo's photographic record was destroyed because of its unexpectedly high yield.

References

* Chuck Hansen, ''U. S. Nuclear Weapons: The Secret History'' (Arlington: AeroFax, 1988)

External links

List of all tested U.S. weapons at The Nuclear Weapon Archive
* * *

{{Nuclear weapons tests of the United States Explosions in 1954 Nuclear testing at Bikini Atoll 1954 in military history 1954 in the environment 1950s in the Marshall Islands 1954 in the Trust Territory of the Pacific Islands March 1954 events in Oceania