Operation Castle was the highest-yield nuclear test series ever conducted by the United States.

Operation Castle was a series of high-energy (high-yield) nuclear tests by Joint Task Force SEVEN (JTF-7) at Bikini Atoll beginning in March 1954. Conducted as a joint venture between the Atomic Energy Commission (AEC) and the Department of Defense (DoD), the ultimate objective of the operation was to test designs for an aircraft-deliverable thermonuclear weapon. Image File history File links Castle_romeo. ... Image File history File links Castle_romeo. ... // The explosive yield of a nuclear weapon is the amount of energy discharged when the weapon is detonated, expressed usually in the equivalent mass of trinitrotoluene (TNT), either in kilotons (thousands of tons of TNT) or megatons (million of tons of TNT), but sometimes also in terajoules (1 kiloton of... A nuclear test explosion is an experiment involving the detonation of a nuclear weapon. ... Bikini Atoll - NASA NLT Landsat 7 (Visible Color) Satellite Image Bikini Atoll (also known as Pikinni Atoll) is an uninhabited 6. ... Shield of the U.S. Atomic Energy Commission. ... The United States Department of Defense, abbreviated DoD or DOD and sometimes called the Defense Department, is a civilian Cabinet organization of the United States government. ... At the end of the 20th century, Thermonuclear has came to imply anything which has to do with fusion nuclear reactions which are triggered by particles of thermal energy. ...

Operation Castle is (largely) considered to be a resounding success for the designs of the weapons, though there were some serious complications. One of the devices was a fizzle, and did not detonate with anything close to its predicted yield. Two other devices detonated with over twice their predicted yields' one shot in particular, Castle Bravo, resulted in extensive radiological contamination of nearby islands (including inhabitants and U.S. soldiers stationed there), as well as a nearby Japanese fishing boat, resulting in one direct fatality and continued health problems for many of those exposed. Public reaction to the tests and the awareness of the long-range effects of nuclear fallout has been attributed to being part of the foundation for the Partial Test Ban Treaty of 1963. A black and white photograph of the Castle Bravo mushroom cloud. ... Map of hypothetical fallout dispersal after a large-scale nuclear attack against the United States. ... The Treaty Banning poop, in Outer Space, and Under Water, often abbreviated as the Partial Test Ban Treaty (PTBT), Limited Test Ban Treaty (LTBT), or Nuclear Test Ban Treaty (NTBT), although the former also refers to the Comprehensive Test Ban Treaty (CTBT), is a treaty intended to obtain an agreement...

Background

AEC Authorization for Operation Castle

Bikini Atoll had previously hosted nuclear weapon testing in 1946 as part of Operation Crossroads where the world’s fourth and fifth atomic weapons were detonated in Bikini Lagoon. Since then, US nuclear weapons testing had moved to Eniwetok Atoll to take advantage of generally larger islands and deeper water (and therefore more real estate to stage experiments and support equipment upon). Both Atolls were part of the US Pacific Proving Grounds, however, the extremely high yields of the Castle weapons caused concern within the AEC that potential damage to the limited infrastructure already established Eniwetok would delay other operations. Additionally, the cratering from the Castle weapons was expected to be comparable to that of Ivy Mike, a 10.4 Mt weapon tested at Eniwetok in 1951 leaving a crater approximately 1 mile (1.6 km) in diameter.^[1] Image File history File links Download high-resolution version (1510x2200, 39 KB) The United States Department of Defense, Defense Nuclear Agency (1982). ... Image File history File links Download high-resolution version (1510x2200, 39 KB) The United States Department of Defense, Defense Nuclear Agency (1982). ... Bikini Atoll - NASA NLT Landsat 7 (Visible Color) Satellite Image Bikini Atoll (also known as Pikinni Atoll) is an uninhabited 6. ... A 21 kiloton underwater nuclear weapons effects test, known as Operation Crossroads (Event Baker), conducted at Bikini Atoll (1946). ... Enewetak (or Eniwetok) is an atoll in the Marshall Islands of the central Pacific Ocean. ... The United States began using the Marshall Islands as a nuclear testing site beginning in 1946. ... The mushroom cloud from the Mike shot. ... A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ...

The Ivy Mike test had been the world’s first thermonuclear explosion that used hydrogen fusion as its primary power source. The Mike device used cryogenic hydrogen isotopes in a liquid state, commonly referred to as a "wet bomb." The complex dewar mechanisms needed to store the liquid hydrogen made the device three stories tall and 82 tons in total weight—completely impractical to be delivered by contemporary weapon systems of the cold war.^[2] With the success of Ivy Mike as a proof of concept, research began on using a solid state “dry fuel” to achieve a practical fusion weapon. The Teller-Ulam design could also use lithium deuteride as the fusion fuel, greatly reducing the size, weight, and complexity. Operation Castle was chartered to test 4 dry fuel designs, 2 wet bombs, and 1 smaller device. Approval for Operation Castle was communicated to JTF-7 by Major General Kenneth D. Nichols, General Manager of the AEC, on 21 January 1954. At the end of the 20th century, Thermonuclear has came to imply anything which has to do with fusion nuclear reactions which are triggered by particles of thermal energy. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... The deuterium-tritium (D-T) fusion reaction is considered the most promising for producing fusion power. ... Cryogenics is the study of very low temperatures or the production of the same, and is often confused with cryobiology, the study of the effect of low temperatures on organisms, or the study of cryopreservation. ... Isotopes are atoms of a chemical element whose nuclei have the same atomic number, Z, but different atomic weights, A. The word isotope, meaning at the same place, comes from the fact that isotopes are located at the same place on the periodic table. ... A Dewar flask is a vessel designed to provide very good thermal insulation. ... For other uses, please see Cold War (disambiguation). ... The basics of the Teller-Ulam configuration: a fission bomb suspended above fusion fuel. ... Lithium hydride (LiH) (also known as Lithium deuteride, when the deuterium isotope of hydrogen is used for the hydrogen component) is a compound of lithium and hydrogen. ... January 21 is the 21st day of the year in the Gregorian calendar. ... 1954 (MCMLIV) was a common year starting on Friday of the Gregorian calendar. ...

Experiments

Operation Castle was organized into 7 experimental detonations, all but one which were to take place at Bikini Atoll. Below is the original test schedule (as of February 1954). ^[3]

Operation Castle was intended to be a proof of concept for lithium deuteride fuels in fusion weapons. The so-called "dry" lithium-6 fuels were a significant advancement in weapon design over the liquid hydrogen used in the Ivy Mike device. Bravo and Union used enriched lithium in the Teller-Ulam configuration where a typical fission weapon is detonated in order to create the temperature and pressure needed for fusion in the lithium fuel capsule. Romeo and Koon used the same Teller-Ulam configuration, however, both were fueled by naturally occurring lithium deuteride (92% Li-7, 7.5% Li-6). The natural fuels, being vastly less time and resource intensive to obtain compared to enriched lithium, were important for US's ability expand the nuclear stockpile during the cold war arms race. A black and white photograph of the Castle Bravo mushroom cloud. ... A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ... The Castle Union test of the Mark 14 design. ... A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ... Castle Yankee was the code name given to one of the tests in the Operation Castle series of American nuclear tests. ... A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ... A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ... A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ... Castle Romeo mushroom cloud. ... A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ... A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ... For the generation of electrical power by fission, see Nuclear power plant An induced nuclear fission event. ... The deuterium-tritium (D-T) fusion reaction is considered the most promising for producing fusion power. ... US and USSR/Russian nuclear weapons stockpiles, 1945-2005. ...

Because the viability of dry fuels was not known, and there was significant risk of failure, development of liquid isotope weapons continued in parallel. Even though they were considered less practical due to logistical problems with transport, handling, and storage of a cryogenic device, the cold war arms race drove a technical demand for a viable weapon. Echo and Yankee were liquid fuel designs that were greatly reduced in size and weight over their Ivy Mike predecessor. The Jughead device was ultimately weaponized, despite the liquid fuel draw-backs, and saw limited fielding in the inventory until the dry fuel weapons were common.

Nectar was not a fusion weapon in the same sense as the rest of the Castle series. Even though it used a dry lithium fuel for fission boosting, the principal reaction material was uranium and plutonium. Similar to the Teller-Ulam configuration, a fission device was used to create high temperatures and pressures in order to compress a second fissionable mass that would have otherwise been too large to sustain an efficient reaction if it were triggered with conventional explosives. This experiment was intended to develop an intermediate yield weapons for expanding the inventory (around 1-2 Mt vice 4-8). For the generation of electrical power by fission, see Nuclear power plant An induced nuclear fission event. ... This article or section should include material from Fissile material In nuclear engineering, a fissile material is one that is capable of sustaining a chain reaction of nuclear fission. ... A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ...

Test execution

The most notable event of Operation Castle was the Bravo test. The dry fuel for Bravo was 40% enriched Li-6, and 60% naturally occurring Li-7, the latter of which was expected to be essentially inert. J. Carson Mark, head of the Los Alamos Theoretical Design Division, had speculated that Bravo could "go big" and estimated that it could be by as much as an additional 20%.^[4] Unexpectedly, the Li-7 was extremely reactive under the fusion conditions and produced a very high neutron and energy surplus through a previously unquantified neutron reaction. Bravo exceeded its expected yield by more than 250%, totaling 15 Mt. 1,000 times more powerful than the Little Boy weapon used on Hiroshima, Bravo is the largest detonation ever conducted by the United States, and the seventh largest weapon ever detonated. J. Carson Mark (July 6, 1913–March 2, 1997) was a Canadian-born American mathematician known especially for his work on developing nuclear weapons for the United States at Los Alamos National Laboratory. ... // The explosive yield of a nuclear weapon is the amount of energy discharged when the weapon is detonated, expressed usually in the equivalent mass of trinitrotoluene (TNT), either in kilotons (thousands of tons of TNT) or megatons (million of tons of TNT), but sometimes also in terajoules (1 kiloton of... A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ... A postwar Little Boy casing mockup. ... For other uses, see Hiroshima (disambiguation). ...

Because Bravo exceeded the designed yield by such a large margin, the JTF-7 was caught unprepared. Much of the permanent infrastructure on Bikini Atoll was heavily damaged. The intense thermal flash ignited fire at distance of 20 nautical miles on the island of Eneu (base island of Bikini Atoll).^[5] The ensuing fallout contaminated almost all of the Atoll to various levels, so much so that it could not be approached by JTF-7 for 24 hours after the test, and even then exposure time were limited.^[6] As the fallout spread downwind, more atolls were contaminated with activated calcium ash. Though people on the atolls were evacuated soon after the test, in the end 239 Marshallese on the Utirik, Rongelap, and Ailinginae Atolls were subjected to significant levels of radiation, and 28 Americans stationed on the Rongerik Atoll were also exposed. Follow-up studies of the contaminated individuals began soon after the blast as Project 4.1, and though the short-term effects of the radiation exposure for most of the Marshallese were mild and/or hard to correlate, the long-term effects were pronounced. Additionally, 23 Japanese fishermen aboard the Lucky Dragon No. 5 were also exposed to high levels of radiation. They suffered symptoms of radiation poisoning, and one crewmember died in the fall of 1955. Bikini Atoll - NASA NLT Landsat 7 (Visible Color) Satellite Image Bikini Atoll (also known as Pikinni Atoll) is an uninhabited 6. ... Map of hypothetical fallout dispersal after a large-scale nuclear attack against the United States. ... Utirik Atoll is an atoll of 10 islands in the Pacific Ocean. ... Rongelap Atoll is an island-atoll located in Micronesia. ... Ailinginae Atoll is an atoll of 25 islands in the Pacific Ocean. ... Rongerik Atoll - NASA NLT Landsat 7 (Visible Color) Satellite Image Map of Rongerik Atoll, taken from the 1893 map Schutzgebiet der Marshall Inseln, published in 1897. ... The neutrality of this article is disputed. ... Daigo Fukuryū Maru Lucky Dragon No. ... Radiation hazard symbol. ...

The heavy contamination and extensive damage from Bravo caused significant delays in the conduct the rest of the series. The post-Bravo schedule was revised on 14 April 1954^[7]. April 14 is the 104th day of the year in the Gregorian calendar (105th in leap years). ... 1954 (MCMLIV) was a common year starting on Friday of the Gregorian calendar. ...

Romeo and Koon were complete by the time of this revision. The Castle Union test of the Mark 14 design. ... A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ... A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ... Castle Yankee was the code name given to one of the tests in the Operation Castle series of American nuclear tests. ... A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ... A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ... A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ... A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ... Castle Romeo mushroom cloud. ... A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ... A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ... A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ... A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ...

The Echo test was canceled due to the liquid fuel design being considered obsolete following the success of the dry fuel in Bravo. The Jughead device was similarly considered obsolete and Yankee was conducted using a Runt II device (similar to the Union device) hastily completed at Los Alamos and flown to Bikini. With this revision, both of the "wet" fuel devices were removed from the test schedule.

As Operation Castle continued, the increased yields and fallout from the dry fuel experiments caused test locations to be re-evaluated. While the majority of the tests were planned for barges near the sand spit of Iroij, some were move to the Bravo and Union craters. Additionally, Nectar was moved from Bikini Atoll to the Ivy Mike crater at Enewetak as a means of expediency since Bikini was still heavily contaminated from the previous tests.^[8] Enewetak (or Eniwetok) is an atoll in the Marshall Islands of the central Pacific Ocean. ...

The final test in Operation Castle took place on 14 May 1954. May 14 is the 134th day of the year in the Gregorian Calendar (135th in leap years). ... 1954 (MCMLIV) was a common year starting on Friday of the Gregorian calendar. ...

A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ... Castle Romeo mushroom cloud. ... A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ... A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ... The Castle Union test of the Mark 14 design. ... A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ... Castle Yankee was the code name given to one of the tests in the Operation Castle series of American nuclear tests. ... A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ... A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ...

Results

Bikini Atoll in the summer 1954 after the completion of Operation Castle.

Operation Castle was an unqualified success for the technical implementation of dry fuels, despite the in some cases large variations from prediction. The Bravo design was quickly weaponized and is suspected to be the progenitor of the Mk-21 gravity bomb. The Mk-21 design project began on 26 March 1954 (just three weeks after Bravo) with production of 275 weapons beginning in the fall of 1955. Romeo, relying on natural lithium, was rapidly turned into the Mk-17 bomb and was available to strategic forces as an Emergency Capability by late summer of 1954. Most of the Castle dry fuel devices eventually appeared in the inventory and ultimately grandfathered the majority of thermonuclear configurations. Image File history File links Bikini_Atoll_Post_BRAVO.gif‎ The United States Department of Defense, Defense Nuclear Agency (1982). ... Image File history File links Bikini_Atoll_Post_BRAVO.gif‎ The United States Department of Defense, Defense Nuclear Agency (1982). ... Bikini Atoll - NASA NLT Landsat 7 (Visible Color) Satellite Image Bikini Atoll (also known as Pikinni Atoll) is an uninhabited 6. ... March 26 is the 85th day of the year in the Gregorian Calendar (86th in leap years). ... 1954 (MCMLIV) was a common year starting on Friday of the Gregorian calendar. ... At the end of the 20th century, Thermonuclear has came to imply anything which has to do with fusion nuclear reactions which are triggered by particles of thermal energy. ...

In contrast, the Livermore-designed Koon design was a failure. Using natural lithium and a heavily modified Teller-Ulam configuration, the test produced only 110 Kt of an expected 1.5 Mt. While engineers at the Radiation Laboratory had hoped it would lead to a promising new field of weapons, it was eventually determined that the design allowed premature heating of the lithium fuel, thereby disrupting the delicate fusion conditions. Aerial view of the lab and surrounding area. ... The basics of the Teller-Ulam configuration: a fission bomb suspended above fusion fuel. ... A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ... A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ...

See also

• Pacific Proving Grounds
• Project 4.1

The United States began using the Marshall Islands as a nuclear testing site beginning in 1946. ... The neutrality of this article is disputed. ...

References

1. ^ Operation Ivy, pg 192
2. ^ Dark Sun, pg 495.
3. ^ Castle Series, pg 247
4. ^ O'Keffe, page 179
5. ^ Castle Series, pg 209
6. ^ Hacker, pg 140
7. ^ Castle Series pg 268
8. ^ Castle Series pg 248.

Bibliography

• The United States Department of Defense, Defense Nuclear Agency (1982). Castle Series. Washington DC: United States Government Printing Office.
• The United States Department of Defense, Defense Nuclear Agency (1983). Operation Ivy--1952. Washington DC: United States Government Printing Office.
• Rhodes, Richard (1995). Dark Sun. New York, New York: Simon & Schuster.
• O'Keefe, Bernard J. (1983). Nuclear Hostages. Boston: Houghton Mifflin Company.
• Hacker, Barton C (1994). Elements of Controversy: The Atomic Energy Commission and Radiation Safety in Nuclear Weapons Testing. Los Angeles: University of California Press.

Richard Rhodes (born July 4, 1937) is an American author of fiction and verity, including the Pulitzer Prize-winning The Making of the Atomic Bomb in 1986, and most recently, John James Audubon: the Making of an American in 2004. ...

External links

• Downloadable/Streamable Declassified Film: Operation Castle Commanders Report, at the Internet Archive
• Downloadable/Streamable Declassified Film: Military Effects Studies Operation Castle, at the Internet Archive
• Operation Castle
• Operation Castle and photos
• Operation Castle: A Radiological Safety Nightmare