54-499: The Koon shot of Operation Castle was a test of a thermonuclear device designed at the University of California Radiation Laboratory (UCRL), now Lawrence Livermore National Laboratory . The "dry" two-stage device was known as "Morgenstern" and had a highly innovative secondary stage. It was tested on April 7, 1954. The predicted yield was between 0.33 and 3.5 megatons, with an expected yield of 1 megaton. The actual yield
108-580: A tamper around a fusion bomb, helping contain the fusion reaction and contributing its own fission energy. For example, the fast-fission of the U-238 tamper contributed 77% (8.0 megatons) to the yield of the 10.4 Mt Ivy Mike explosion. The most notable event of Operation Castle was the Castle Bravo test. The dry fuel for Bravo was 40% Li-6 and 60% Li-7. Only the Li-6 was expected to breed tritium for
162-644: A "wet" bomb. The complex dewar mechanisms needed to store the liquid deuterium at cryogenic temperatures made the device three stories tall and 82 tons in total weight, far too heavy and bulky to be a usable weapon. With the success of Ivy Mike as proof of the Teller-Ulam bomb concept, research began on using a "dry" fuel to make a practical fusion weapon so that the United States could begin production and deployment of thermonuclear weapons in quantity. The final result incorporated lithium deuteride as
216-517: A 28% to 69% uncertainty range) among 82 persons exposed in 1954 on Rongelap Atoll and Ailinginae Atoll , 10% (2.4% to 22%) for 157 persons exposed on Utirik Atoll , and 2.2% (0.5% to 4.8%) and 0.8% (0.2% to 1.8%), respectively, for the much larger populations exposed in mid-latitude locations including Kwajalein and in southern locations including Majuro . Since 1956, the U.S. has paid at least $ 759 million to Marshall Islanders as compensation for their exposure to U.S. nuclear testing. Following
270-442: A fire at a distance of 20 nautical miles (37 km) on the island of Eneu (base island of Bikini Atoll). The ensuing fallout contaminated all of the atoll, so much so that it could not be approached by JTF-7 for 24 hours after the test, and even then, exposure times were limited. As the fallout spread downwind to the east, more atolls were contaminated by radioactive calcium ash from the incinerated underwater coral banks. Although
324-501: A heavily modified Teller-Ulam configuration, the test produced only 110 kilotons of an expected 1.5 megaton yield. 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. Pacific Proving Grounds The Pacific Proving Grounds
378-586: 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. All the devices tested, which ranged in weight from 6,520 to 39,600 pounds (2,960 to 17,960 kg), were built to be dropped from aircraft. However, ballistic casings, fins and fusing systems would have to be attached. Operation Castle
432-682: A live warhead ever undertaken by the USA). The signing of the Partial Test Ban Treaty in 1963 forbade atmospheric and underwater nuclear weapons, and so no further U.S. tests were conducted at the Pacific Proving Grounds, with all but ten occurring at the Nevada Test Site until the end of testing in 1992. The Bikini and Enewetak Atolls are each a collection of islands. Various names have been assigned to
486-502: A nearby Japanese fishing boat (the Daigo Fukuryū Maru ), resulting in one direct fatality and continued health problems for many of those exposed. Public reaction to the tests and an awareness of the long-range effects of nuclear fallout has been attributed as being part of the motivation for the Partial Test Ban Treaty of 1963. Bikini Atoll had previously hosted nuclear testing in 1946 as part of Operation Crossroads where
540-582: A secondary concept similar to that first tested in the Koon shot. This United States military article is a stub . You can help Misplaced Pages by expanding it . Operation Castle Download coordinates as: 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 . Conducted as
594-634: Is not surrounded by a reef. The island does not support the inhabitants' traditional way of life. Because of the large amount of atmospheric testing, and especially the Castle Bravo accident of 1954, many of the islands which were part of the Pacific Proving Grounds are still contaminated by nuclear fallout . Scientists calculated in 2010 that during the lifetimes of members of the Marshall Islands population, potentially exposed to ionizing radiation from weapons test fallout deposited during
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#1732794525561648-521: Is the original test schedule (as of February 1954). The Echo test was canceled due to the liquid fuel design becoming obsolete with the success of dry-fueled Bravo as noted above. Yankee was similarly considered obsolete, and the Jughead device was replaced with a "Runt II" device (similar to the Union device ), which was hastily completed at Los Alamos and flown to Bikini. With this revision, both of
702-463: The Little Boy weapon used on Hiroshima . Castle Bravo remains, to this day, the largest detonation ever carried out anywhere by the United States and the fifth largest H-bomb detonation in the world. Because Castle Bravo greatly exceeded its expected yield, JTF-7 was caught unprepared. Much of the permanent infrastructure on Bikini Atoll was heavily damaged. The intense thermal flash ignited
756-653: The Radiation Exposure Compensation Act of 1990, at least $ 759 million has been paid to Marshall Islanders as compensation for their exposure to U.S. nuclear testing. Following the Castle Bravo accident, the U.S. paid $ 15.3 million to Japan . Scientists have calculated that the residents of the Marshall Islands during their lifetimes will be diagnosed with an added 1.6% (with 90% uncertainty range 0.4% to 3.4%) cancers attributable to fallout-related radiation exposures. The cancers are
810-660: The United States Atomic Energy Commission established the Pacific Proving Grounds. The United States conducted 105 atmospheric and underwater (i.e., not underground ) nuclear tests in the Pacific, many with extremely high yields. While the Marshall Islands testing composed 14% of all U.S. tests, it composed nearly 80% of the total yields of those detonated by the U.S., with an estimated total yield of around 210 megatons , with
864-528: The Bikini Atoll, Enewetak Atoll, and Johnston Island as part of Operation Hardtack I in 1958. Thirty-six weapons were detonated at sites in the Pacific Ocean in the vicinity of Christmas Island and Johnston Atoll as part of Operation Dominic I . Though these tests were not conducted in the Marshall Islands, they are officially considered part of the Pacific Proving Grounds. The portion of
918-653: The Castle Bravo accident on March 1, 1954, the U.S. paid $ 15.3 million to Japan . In June 1983, the U.S. and the Marshall islanders signed the Compact of Free Association , which gave the Marshall Islands independence. The Compact became effective in 1986 and was subsequently modified by the Amended Compact that became effective in 2004. It also established the Nuclear Claims Tribunal , which
972-608: The Dominic series of tests that were high altitude nuclear explosions were known as Operation Fishbowl , though not all were successful (one detonated on launchpad and resulted in a substantial plutonium contamination). Two of the tests were of operational weapons systems—the ASROC anti-submarine rocket and the Polaris SLBM (the latter test, Frigate Bird, was the only operational submarine-launched ballistic missile test with
1026-492: The Enewetak Atoll as part of Operation Greenhouse in 1951. Two are of particular note: Greenhouse "Item" was the first use of a boosted fission weapon , and "George" was a thermonuclear experiment designed to prove the feasibility of the Teller-Ulam design for the possibility of developing hydrogen bombs . Two weapons were detonated at the Enewetak Atoll as part of Operation Ivy in 1952. One of them, Ivy King ,
1080-679: The Japanese fishing vessel, the Daigo Fukuryu Maru , were additionally exposed and one man died soon after from complications of radiation sickness , resulting in considerable international controversy. Seventeen nuclear weapons were detonated on the Bikini and Enewetak Atolls as part of Operation Redwing in 1956. Many of them were designed to prove the feasibility of numerous thermonuclear weapon designs, with yields ranging from around 2 to 5 Mt. Thirty-five weapons were detonated at
1134-522: The LiD devices would fuse deuterium with tritium. The tritium was produced during the explosion by irradiating the lithium with fast neutrons . Bravo , Yankee (II) , and Union used lithium enriched in the Li-6 isotope ( Bravo and Yankee used lithium enriched to 40% Li-6, while the lithium used in Union was enriched to 95% Li-6), while Romeo and Koon were fueled with natural lithium (92% Li-7, 7.5% Li-6). The use of natural lithium would be important to
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#17327945255611188-529: The Marshallese were mild and/or hard to correlate, the long-term effects were pronounced. Additionally, 23 Japanese fishermen aboard Daigo Fukuryū Maru were also exposed to high levels of radiation. They suffered symptoms of radiation poisoning , and one crew member died in September 1954. The heavy contamination and extensive damage from Bravo delayed the rest of the series. A revised test schedule
1242-510: The Nuclear Claims Tribunal ruled against the United States for damages done to the islands and its people. The Nuclear Claims Tribunal awarded the islanders a total of $ 563,315,500 after deducting past awards. However, the U.S. Congress has failed to fund the settlement. The only recourse is for the Bikini people to petition the U.S. Congress to fund the payment and fulfill this award. The United States Supreme Court turned down
1296-757: The United States secured an agreement with the United Nations to govern the islands of Micronesia as the Trust Territory of the Pacific Islands , a strategic trusteeship territory . This is the only such trusteeship ever granted by the United Nations to the United States. The Trust Territory comprised about 2,000 islands spread over 3,000,000 square miles (7,800,000 km ) of the North Pacific Ocean . Five days later,
1350-710: The United States should "promote the economic advancement and self-sufficiency of the inhabitants, and to this end shall... protect the inhabitants against the loss of their lands and resources..." The United States Navy controlled the Trust from a headquarters in Guam until 1951, when the United States Department of the Interior took over control, administering the territory from a base in Saipan . Despite
1404-444: The United States. Its yield, at 15 Mt, was over twice as powerful as was predicted, and remains the largest weapon ever detonated by the United States. It spread nuclear fallout over a wide area, including the Enewetak Atoll, Rongerik Atoll , Ailinginae Atoll , and Rongelap Atoll . The U.S. Navy evacuated the islanders within the next few days, but many of the natives were exposed to radiation prior to evacuation. The fishermen aboard
1458-534: The ability of the US to rapidly expand its nuclear stockpile during the Cold War nuclear arms race since the so-called "Alloy Development Plants" were in an early stage at the time Castle was carried out. The first plant started production in late 1953. As a hedge, the development of liquid deuterium weapons continued in parallel. Even though they were much less practical because of the logistical problems dealing with
1512-516: The atolls were evacuated soon after the test, 239 Marshallese on the Utirik , Rongelap , and Ailinginae Atolls were subjected to significant levels of radiation. 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
1566-504: The consequence of exposure to ionizing radiation from weapons test fallout deposited during the testing period (1948–1958) and from residual radioactive sources during the subsequent 12 years (1959–1970). On July 18, 1947, the United States convinced the United Nations to designate the islands of Micronesia as the Strategic Trust Territory . This was the only trust ever granted by the U.N. The directive stated that
1620-547: The cratering from the Castle weapons was expected to be comparable to that of Ivy Mike , a 10.4 megatons of TNT (Mt) device tested at Enewetak in 1952 leaving a crater approximately 1 mile (1.6 km) in diameter marking the location of the obliterated test island Elugelab . The Ivy Mike test was the world's first "hydrogen bomb", producing a full-scale thermonuclear or fusion explosion. The Ivy Mike device used liquid deuterium , an isotope of hydrogen , making it
1674-700: The deuterium-tritium fusion reaction; the Li-7 was expected to be inert. Yet J. Carson Mark , the head of the Los Alamos Theoretical Design Division, had speculated that Bravo could "go big", estimating that the device could produce an explosive yield as much as 20% more than had been originally calculated. It was discovered, because of the unexpected larger yield, that the Li-7 in the device also undergoes breeding that produces tritium. In practice, Bravo exceeded expectations by 150%, yielding 15 Mt — about 1,000 times more powerful than
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1728-456: The entire Bikini population, while the remaining $ 2.6 million is paid into The Bikini Claims Trust Fund . This trust is intended to exist in perpetuity and to provide the islanders a 5% payment from the trust annually. The United States also passed the Radiation Exposure Compensation Act in 1990 to allow individuals to file claims for compensation in relation to testing as well as those employed at nuclear weapons facilities. On March 5, 2001,
1782-399: The first nuclear testing done after the atomic bombing of Hiroshima and Nagasaki . Two fission bombs, both with a yield of 21 kilotons, were tested at Bikini Atoll . "Able" was detonated at an altitude of 520 ft (158 m) on July 1, 1946, and "Baker" was detonated at a depth of 90 ft (27 m) underwater on July 25. Both tests used a flotilla of obsolete vessels from World War II with
1836-655: The fusion fuel in the Teller-Ulam design, vastly reducing size and weight and simplifying the overall design. Operation Castle was charted to test four dry fuel designs, two wet bombs, and one smaller device. The approval for Operation Castle was issued to JTF-7 by Major General Kenneth D. Nichols , the General Manager of the AEC, on January 21, 1954. Operation Castle was organized into seven experiments, all but one of which were to take place at Bikini Atoll. Below
1890-495: The intent of learning the effects of nuclear weapons on naval fleets. The "Baker" shot created a large condensation cloud and spread much more radioactive water onto the ships than was expected; many of the surviving ships became too "hot" to be used or decontaminated and eventually had to be sunk. Three weapons were detonated on the Enewetak Atoll as part of Operation Sandstone in 1948. Four weapons were detonated on
1944-466: The islanders' appeal of the United States courts of appeals decision that refused to compel the government to fund their claim. As of 2012 , trusts remaining from the settlement produced about US$ 6 to $ 8 million annually in investment income, and the trusts paid out about US$ 15,000 per family each year in benefits. The first use of the Pacific Proving Grounds was during Operation Crossroads ,
1998-423: The islands over time, and the confusion over the names (and their alternate transliterations) have been the source of much confusion. In addition, some islands over time have appeared, disappeared, separated, joined, and been excavated by bombs. Here are the islands listed in clockwise fashion starting with left side of the major inlet into the lagoon in each atoll. The names include the official Marshall Island names,
2052-470: The largest being the 15 Mt Castle Bravo shot of 1954 which spread considerable nuclear fallout on many of the islands, including several that were inhabited and some that had not been evacuated. Many of the islands which were part of the Pacific Proving Grounds are still contaminated from the nuclear fallout , and many of those who were living on the islands at the time of testing have suffered from an increased incidence of various health problems. Through
2106-530: The promise to "protect the inhabitants", from July 1946 through July 1947, the residents of Bikini Atoll who had been relocated to Rongerik Atoll were starving for lack of food. A team of U.S. investigators concluded in late 1947 that the islanders must be moved immediately. Press from around the world harshly criticized the U.S. Navy for ignoring the people. Harold Ickes , a syndicated columnist, wrote "The natives are actually and literally starving to death." The islanders were later moved again to Kili Island , which
2160-449: The same design defect. The name "Morgenstern" (German for morning star) was chosen because of the shape of the secondary. The secondary consisted of a central sphere from which spikes were radiating, resembling a morning star / mace . The spikes may have been an idea from physicist Edward Teller and colleagues to use implosive jets to compress the thermonuclear core . It was more than two decades before weapons were designed that utilized
2214-408: The testing period (1948–1958) and from residual radioactive sources during the subsequent 12 years (1959–1970), perhaps 1.6% (with 90% uncertainty range 0.4% to 3.4%) of all cancers might be attributable to fallout-related radiation exposures. By sub-population, the projected proportion of cancers attributable to radiation from fallout from all nuclear tests conducted in the Marshall Islands is 55% (with
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2268-476: The transport, handling, and storage of a cryogenic device, the Cold War arms race drove the demand for a viable fusion weapon. The "Ramrod" and "Jughead" devices were liquid fuel designs greatly reduced in size and weight from their so-called "Sausage" predecessor. The "Jughead" device was eventually weaponized, and it saw limited fielding by the U.S. Air Force until the "dry" fuel H-bombs became common. Nectar
2322-589: The wet fuel devices were removed from the test schedule. Operation Castle was intended to test lithium deuteride (LiD) as a thermonuclear fusion fuel. A solid at room temperature, LiD, if it worked, would be far more practical than the cryogenic liquid deuterium fuel in the Ivy Mike device. The same Teller-Ulam principle would be used as in the Ivy Mike so-called "Sausage" device, but the fusion reactions were different. Ivy Mike fused deuterium with deuterium, but
2376-698: The world's fourth and fifth atomic weapons were detonated in Bikini Lagoon. Since then, American nuclear weapons testing had moved to the Enewetak Atoll to take advantage of generally larger islands and deeper water. Both atolls were part of the American Pacific Proving Grounds . The extremely high yields of the Castle weapons caused concern within the AEC that potential damage to the limited infrastructure already established at Enewetak would delay other operations. Additionally,
2430-466: Was 0.11 megatons. Morgenstern was thus a fizzle . Post-shot analysis showed that the failure was caused by the premature heating of the secondary by the neutron flux of the primary. This was a simple design defect and not related to the unique geometry of the secondary. The UCRL's other shot, the "wet" (i.e., cryogenic) ramrod device, originally scheduled for the Echo shot, was cancelled because it shared
2484-537: Was considered by government officials to be a success as it proved the feasibility of deployable "dry" fuel designs for thermonuclear weapons . There were technical difficulties with some of the tests: one device had a yield much lower than predicted (a " fizzle "), while two other bombs detonated with over twice their predicted yields. One test in particular, Castle Bravo , resulted in extensive radiological contamination. The fallout affected nearby islands, including inhabitants and U.S. soldiers stationed there, as well as
2538-564: Was given the task of adjudicating compensation for victims and families affected by the nuclear testing program. Section 177 of the compact provided for reparations to the Bikini islanders and other northern atolls for damages. It included $ 150 million to be paid over a 15-year period ending in 2001. During that time, payments averaging about $ 18 million per year were made to the peoples of Bikini, Enewetak, Rongelap, and Utrik for medical and radiological monitoring, and in response to claims. The payments began in 1987 with $ 2.4 million paid annually to
2592-481: Was intended to develop intermediate yield weapons for expanding the inventory (around 1-2 Mt vs. 4-8). Many fusion or thermonuclear weapons generate much, or even most, of their yields from fission. Although the U-238 isotope of uranium will not sustain a chain reaction, it still fissions when irradiated by the intense fast neutron flux of a fusion explosion. Because U-238 is plentiful and has no critical mass , it can be added in (in theory) almost unlimited quantities as
2646-715: Was moved from Bikini Atoll to the crater of Ivy Mike at Eniwetok for expediency, since Bikini was still heavily contaminated from the previous tests. The final test in Operation Castle took place on May 14, 1954. Operation Castle was an unqualified success for the implementation of dry fuel devices. 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 March 26, 1954 (just three weeks after Bravo ), with production of 275 weapons beginning in late 1955. Romeo , relying on natural lithium,
2700-518: Was not a fusion weapon in the same sense as the rest of the Castle series. Even though it used lithium fuel for fission boosting , the principal reaction material in the second stage was uranium and plutonium. Similar to the Teller-Ulam configuration, a nuclear fission explosion was used to create high temperatures and pressures to compress a second fissionable mass. This would have otherwise been too large to sustain an efficient reaction if it were triggered with conventional explosives. This experiment
2754-413: Was officially released on April 14, 1954. The Castle Romeo and Koon tests were complete by the time this revision was published. As Operation Castle progressed, the increased yields and fallout caused test locations to be reevaluated. While the majority of the tests were planned for barges near the sand spit of Iroij, some were moved to the craters of Bravo and Union . In addition, Castle Nectar
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#17327945255612808-520: Was rapidly turned into the Mk-17 bomb , the first deployable US thermonuclear weapon , and was available to strategic forces as an Emergency Capability weapon by mid-1954. Most of the Castle dry fuel devices eventually appeared in the inventory and ultimately grandfathered the majority of thermonuclear configurations. In contrast, the Livermore -designed Koon was a failure. Using natural lithium and
2862-510: Was the largest pure-fission bomb ever detonated, with a yield of 500 kilotons , and the other, Ivy Mike , was the first hydrogen bomb device (it was too large to be an actual weapon), with a yield of 10.4 Mt . Six very large nuclear tests were conducted at the Bikini Atoll and the Enewetak Atoll as part of Operation Castle in 1954. The most notable was Castle Bravo , which was the first deployable (dry fuel) hydrogen bomb developed by
2916-501: Was the name given by the United States government to a number of sites in the Marshall Islands and a few other sites in the Pacific Ocean at which it conducted nuclear testing between 1946 and 1962. The U.S. tested a nuclear weapon (codenamed Able ) on Bikini Atoll on June 30, 1946. This was followed by Baker on July 24, 1946 (dates are Universal Time , local dates were July 1 and 25, respectively). On July 18, 1947,
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