173-596: Operation Sandstone was a series of nuclear weapon tests in 1948. It was the third series of American tests, following Trinity in 1945 and Crossroads in 1946, and preceding Ranger . Like the Crossroads tests, the Sandstone tests were carried out at the Pacific Proving Grounds , although at Enewetak Atoll rather than Bikini Atoll . They differed from Crossroads in that they were conducted by
346-427: A British Mission headed by Oliphant that included fellow Australian physicists Harrie Massey and Eric Burhop , and British physicists such as Joan Curran and Thomas Allibone . Lawrence had a large cyclotron under construction at Berkeley, one with a 184-inch (470 cm) magnet. This was converted into a calutron that was switched on for the first time on 26 May 1942. Like the 37-inch version, it looked like
519-513: A misnomer , as their energy comes from the nucleus of the atom, just as it does with fusion weapons. In fission weapons, a mass of fissile material ( enriched uranium or plutonium ) is forced into supercriticality —allowing an exponential growth of nuclear chain reactions —either by shooting one piece of sub-critical material into another (the "gun" method) or by compression of a sub-critical sphere or cylinder of fissile material using chemically fueled explosive lenses . The latter approach,
692-665: A policy of deliberate ambiguity , it does not acknowledge having them. Germany , Italy , Turkey , Belgium , the Netherlands , and Belarus are nuclear weapons sharing states. South Africa is the only country to have independently developed and then renounced and dismantled its nuclear weapons. The Treaty on the Non-Proliferation of Nuclear Weapons aims to reduce the spread of nuclear weapons, but there are different views of its effectiveness. There are two basic types of nuclear weapons: those that derive
865-563: A 200-tank section of a production plant. Between October 1942 and November 1943, Groves paid monthly visits to the Radiation Laboratory in Berkeley. Reports indicated that compared to the alternatives of a gaseous diffusion plant or a plutonium -producing nuclear reactor , an electromagnetic plant would take longer and require more scarce materials to build, and need more manpower and more electricity to operate. The cost of
1038-458: A 24-fold magnification of the XA calutron that could hold 96 calutron Alpha tanks. The calutrons were upright and arrayed facing each other in pairs of inner and outer machines. To minimize magnetic losses, and to economize on steel consumption, the assembly was curved into an oval shape that formed a closed magnetic loop 122 feet (37 m) long, 77 feet (23 m) wide and 15 feet (4.6 m) high, in
1211-422: A bomb by mid-1943, based on new estimates from Robert Oppenheimer that the critical mass of a sphere of pure uranium-235 was between 2.0 and 2.5 kilograms. The experiments with the 184-inch magnet led to the construction of a prototype calutron called the XA. It contained a rectangular, three-coil magnet with a horizontal field in which the calutron tanks could stand side by side, with four vacuum tanks, each with
1384-463: A compromise, the Sandstone detonations all took place shortly before dawn. The detonations in the United States' Sandstone series are listed below: The X-Ray nuclear device used a levitated composite core. It was detonated on Enjebi just before sunrise at 06:17 on April 15, 1948, with a yield of 37 kilotons. The efficiency of utilization of the plutonium was about 35%; that of the uranium-235
1557-696: A conference—called for in the manifesto—in Pugwash, Nova Scotia , Eaton's birthplace. This conference was to be the first of the Pugwash Conferences on Science and World Affairs , held in July 1957. By the 1960s, steps were taken to limit both the proliferation of nuclear weapons to other countries and the environmental effects of nuclear testing . The Partial Nuclear Test Ban Treaty (1963) restricted all nuclear testing to underground nuclear testing , to prevent contamination from nuclear fallout, whereas
1730-730: A double source. At the 25 June 1942 meeting of the S-1 Executive Committee, which had superseded the S-1 Uranium Committee on 19 June, there was a proposal to build the electromagnetic plant at Oak Ridge, where the other Manhattan Project uranium separation facilities would be located, for reasons of economy and security. Lawrence lodged an objection due to his desire to have the electromagnetic separation plant located much nearer to Berkeley. The Shasta Dam area in California remained under consideration for
1903-458: A faster and less vulnerable attack, the development of long-range intercontinental ballistic missiles (ICBMs) and submarine-launched ballistic missiles (SLBMs) has given some nations the ability to plausibly deliver missiles anywhere on the globe with a high likelihood of success. More advanced systems, such as multiple independently targetable reentry vehicles (MIRVs), can launch multiple warheads at different targets from one missile, reducing
SECTION 10
#17327732107412076-614: A few nations possess such weapons or are suspected of seeking them. The only countries known to have detonated nuclear weapons—and acknowledge possessing them—are (chronologically by date of first test) the United States , the Soviet Union (succeeded as a nuclear power by Russia ), the United Kingdom , France , China , India , Pakistan , and North Korea . Israel is believed to possess nuclear weapons, though, in
2249-492: A fission bomb to initiate them. Such a device might provide a simpler path to thermonuclear weapons than one that required the development of fission weapons first, and pure fusion weapons would create significantly less nuclear fallout than other thermonuclear weapons because they would not disperse fission products. In 1998, the United States Department of Energy divulged that the United States had, "...made
2422-421: A fusion weapon as of January 2016 , though this claim is disputed. Thermonuclear weapons are considered much more difficult to successfully design and execute than primitive fission weapons. Almost all of the nuclear weapons deployed today use the thermonuclear design because it results in an explosion hundreds of times stronger than that of a fission bomb of similar weight. Thermonuclear bombs work by using
2595-427: A giant C when viewed from above. The operator sat in the open end, whence the temperature could be regulated, the position of the electrodes adjusted, and even components replaced through an airlock while it was running. The new, more powerful calutron was not used to produce enriched uranium, but for experiments with multiple ion sources. This meant having more collectors, but it multiplied the throughput. The problem
2768-412: A helicopter to check on the cable winch which was to collect samples. It also lowered boats to test radioactivity levels in the lagoon. B-17 pilotless drone aircraft were flown through the clouds, and a drone light tank was used to recover soil samples from the crater. Unfortunately, it became bogged and had to be towed out ten days later. The Yoke nuclear device used a levitated all-uranium-235 core. It
2941-444: A kilogram of fissile material would therefore be much greater. On the other hand, while the alternative processes still faced considerable technical obstacles, the electromagnetic process was proven to work, and could be built in stages that would immediately start producing fissile material. Groves cancelled the pilot plant on 14 November, in favor of proceeding immediately with the production plant. The Radiation Laboratory forwarded
3114-571: A level in 1945, when only between 4 and 6 kilograms (8.8 and 13.2 lb) was produced per month. A Fat Man core required about 6.2 kilograms (14 lb) of plutonium, of which 21% fissioned. Plutonium production fell off during 1946 due to swelling of the reactors' graphite neutron moderators . This is known as the Wigner effect , after its discoverer, the Manhattan Project scientist Eugene Wigner . These reactors were also required for
3287-911: A monthly accounting to the Treasury. The 1,000-troy-ounce (31 kg) silver bars were taken under guard to the Defense Plant Corporation in Carteret, New Jersey , where they were cast into cylindrical billets, and then to Phelps Dodge in Bayway, New Jersey , where they were extruded into strips 0.625 inches (15.9 mm) thick, 3 inches (7.6 cm) wide and 40 feet (12 m) long. Some 258 carloads were shipped under guard by rail to Allis-Chalmers in Milwaukee, Wisconsin , where they were wound onto magnetic coils and sealed into welded casings. Finally, they moved by unguarded flatcars to
3460-472: A nation's economic electronics-based infrastructure. Because the effect is most effectively produced by high altitude nuclear detonations (by military weapons delivered by air, though ground bursts also produce EMP effects over a localized area), it can produce damage to electronics over a wide, even continental, geographical area. Research has been done into the possibility of pure fusion bombs : nuclear weapons that consist of fusion reactions without requiring
3633-537: A new nuclear strategy, one that is distinct from that which gave relative stability during the Cold War. Since 1996, the United States has had a policy of allowing the targeting of its nuclear weapons at terrorists armed with weapons of mass destruction . Robert Gallucci argues that although traditional deterrence is not an effective approach toward terrorist groups bent on causing a nuclear catastrophe, Gallucci believes that "the United States should instead consider
SECTION 20
#17327732107413806-425: A nuclear war between two nations would result in mutual annihilation. From this point of view, the significance of nuclear weapons is to deter war because any nuclear war would escalate out of mutual distrust and fear, resulting in mutually assured destruction . This threat of national, if not global, destruction has been a strong motivation for anti-nuclear weapons activism. Critics from the peace movement and within
3979-411: A nuclear weapon from another country by threatening nuclear retaliation is known as the strategy of nuclear deterrence . The goal in deterrence is to always maintain a second strike capability (the ability of a country to respond to a nuclear attack with one of its own) and potentially to strive for first strike status (the ability to destroy an enemy's nuclear forces before they could retaliate). During
4152-465: A nuclear weapon is a gravity bomb dropped from aircraft ; this was the method used by the United States against Japan in 1945. This method places few restrictions on the size of the weapon. It does, however, limit attack range, response time to an impending attack, and the number of weapons that a country can field at the same time. With miniaturization, nuclear bombs can be delivered by both strategic bombers and tactical fighter-bombers . This method
4325-409: A nuclear weapon to its target is an important factor affecting both nuclear weapon design and nuclear strategy . The design, development, and maintenance of delivery systems are among the most expensive parts of a nuclear weapons program; they account, for example, for 57% of the financial resources spent by the United States on nuclear weapons projects since 1940. The simplest method for delivering
4498-433: A nuclear weapon with suitable materials (such as cobalt or gold ) creates a weapon known as a salted bomb . This device can produce exceptionally large quantities of long-lived radioactive contamination . It has been conjectured that such a device could serve as a "doomsday weapon" because such a large quantity of radioactivities with half-lives of decades, lifted into the stratosphere where winds would distribute it around
4671-421: A policy of expanded deterrence, which focuses not solely on the would-be nuclear terrorists but on those states that may deliberately transfer or inadvertently leak nuclear weapons and materials to them. By threatening retaliation against those states, the United States may be able to deter that which it cannot physically prevent.". Graham Allison makes a similar case, arguing that the key to expanded deterrence
4844-527: A process of gaseous diffusion , but Oliphant had pioneered another technique in 1934: electromagnetic separation. This was the process that Nier had used. The principle of electromagnetic separation is that charged ions are deflected by a magnetic field, and lighter ones are deflected more than heavy ones. The reason the Maud Committee, and later its American counterpart, the S-1 Section of
5017-444: A production race and Lawrence lost, a morale boost for the " Calutron Girls " (called Cubicle Operators at the time) and their supervisors. The women were trained like soldiers not to reason why, while "the scientists could not refrain from time-consuming investigation of the cause of even minor fluctuations of the dials". For a while, the calutrons suffered from a series of debilitating breakdowns and equipment failures, exacerbated by
5190-618: A profound effect. Practically every component of the old weapons was rendered obsolete. Even before the third test had been carried out, Bradbury had halted production of the old cores, and ordered that all effort was to be concentrated on the Mark 4 nuclear bomb , which would become the first mass-produced nuclear weapon. The more efficient use of fissionable material would increase the nuclear stockpile from 56 bombs in June 1948 to 169 in June 1949. The Mark III bombs were withdrawn from service in 1950. At
5363-600: A shortage of spare parts. Hopes that the Alpha II racetracks would be more reliable soon faded, as they were plagued by insulator failures. These problems were gradually overcome. The first shipments of enriched uranium to the Manhattan Project's Los Alamos Laboratory were made in March 1944, consisting of Alpha product enriched to 13 to 15 percent uranium-235. While of no use in a bomb, it was urgently required for experiments with enriched uranium. The last shipment of Alpha product
Operation Sandstone - Misplaced Pages Continue
5536-447: A significant portion of their energy from fission reactions used to "trigger" fusion reactions, and fusion reactions can themselves trigger additional fission reactions. Only six countries—the United States , Russia , the United Kingdom , China , France , and India —have conducted thermonuclear weapon tests. Whether India has detonated a "true" multi-staged thermonuclear weapon is controversial. North Korea claims to have tested
5709-550: A substantial investment" in the past to develop pure fusion weapons, but that, "The U.S. does not have and is not developing a pure fusion weapon", and that, "No credible design for a pure fusion weapon resulted from the DOE investment". Nuclear isomers provide a possible pathway to fissionless fusion bombs. These are naturally occurring isotopes ( Hf being a prominent example) which exist in an elevated energy state. Mechanisms to release this energy as bursts of gamma radiation (as in
5882-534: A total of 288 calutrons, although only 216 of them were ever operated. Work on the new Beta process building commenced on 20 October 1943. Equipment installation began on 1 April 1944, and it was ready for use on 10 September 1944. A third Beta process building, 9204-3, was authorized in May 1944 to process the output of the K-25 gaseous diffusion plant. It was completed on 15 May 1945. A fourth Beta process building, 9204-4,
6055-533: A worker from exposure to phosgene also prompted a search for a safer production process. In February 1945, slightly enriched 1.4 percent uranium-235 feed material began arriving from the S-50 liquid thermal diffusion plant . Shipments of product from S-50 were discontinued in April. S-50 product was fed into K-25 instead. In March 1945, Y-12 began receiving feed enriched to 5 percent from K-25. The output of these plants
6228-420: Is a thermonuclear weapon that yields a relatively small explosion but a relatively large amount of neutron radiation . Such a weapon could, according to tacticians, be used to cause massive biological casualties while leaving inanimate infrastructure mostly intact and creating minimal fallout. Because high energy neutrons are capable of penetrating dense matter, such as tank armor, neutron warheads were procured in
6401-721: Is an explosive device that derives its destructive force from nuclear reactions , either fission (fission bomb) or a combination of fission and fusion reactions ( thermonuclear bomb ), producing a nuclear explosion . Both bomb types release large quantities of energy from relatively small amounts of matter . The first test of a fission ("atomic") bomb released an amount of energy approximately equal to 20,000 tons of TNT (84 TJ ). The first thermonuclear ("hydrogen") bomb test released energy approximately equal to 10 million tons of TNT (42 PJ). Nuclear bombs have had yields between 10 tons TNT (the W54 ) and 50 megatons for
6574-456: Is analogous to identifying a criminal by fingerprints. "The goal would be twofold: first, to deter leaders of nuclear states from selling weapons to terrorists by holding them accountable for any use of their weapons; second, to give leaders every incentive to tightly secure their nuclear weapons and materials." According to the Pentagon's June 2019 " Doctrine for Joint Nuclear Operations " of
6747-403: Is coming up with ways of tracing nuclear material to the country that forged the fissile material. "After a nuclear bomb detonates, nuclear forensics cops would collect debris samples and send them to a laboratory for radiological analysis. By identifying unique attributes of the fissile material, including its impurities and contaminants, one could trace the path back to its origin." The process
6920-481: Is for the purpose of achieving different yields for different situations , and in manipulating design elements to attempt to minimize weapon size, radiation hardness or requirements for special materials, especially fissile fuel or tritium. Some nuclear weapons are designed for special purposes; most of these are for non-strategic (decisively war-winning) purposes and are referred to as tactical nuclear weapons . The neutron bomb purportedly conceived by Sam Cohen
7093-503: Is no evidence that it is feasible beyond the military domain. However, the U.S. Air Force funded studies of the physics of antimatter in the Cold War , and began considering its possible use in weapons, not just as a trigger, but as the explosive itself. A fourth generation nuclear weapon design is related to, and relies upon, the same principle as antimatter-catalyzed nuclear pulse propulsion . Most variation in nuclear weapon design
Operation Sandstone - Misplaced Pages Continue
7266-409: Is not a fusion bomb. In the boosted bomb, the neutrons produced by the fusion reactions serve primarily to increase the efficiency of the fission bomb. There are two types of boosted fission bomb: internally boosted, in which a deuterium-tritium mixture is injected into the bomb core, and externally boosted, in which concentric shells of lithium-deuteride and depleted uranium are layered on the outside of
7439-490: Is not clear that this has ever been implemented, and their plausible use in nuclear weapons is a matter of dispute. The other basic type of nuclear weapon produces a large proportion of its energy in nuclear fusion reactions. Such fusion weapons are generally referred to as thermonuclear weapons or more colloquially as hydrogen bombs (abbreviated as H-bombs ), as they rely on fusion reactions between isotopes of hydrogen ( deuterium and tritium ). All such weapons derive
7612-591: Is that?" he asked. In fact I did not know how to convert tons to troy ounces, and neither did he. A little impatient, I responded, "I don't know how many troy ounces we need but I know I need six thousand tons—that is a definite quantity. What difference does it make how we express the quantity?" He replied rather indignantly, "Young man, you may think of silver in tons, but the Treasury will always think of silver in troy ounces." Eventually, 14,700 short tons (13,300 tonnes; 430,000,000 troy ounces) of silver were used, then worth over $ 600 million. Nichols had to provide
7785-454: Is the primary means of nuclear weapons delivery; the majority of U.S. nuclear warheads, for example, are free-fall gravity bombs, namely the B61 , which is being improved upon to this day. Preferable from a strategic point of view is a nuclear weapon mounted on a missile , which can use a ballistic trajectory to deliver the warhead over the horizon. Although even short-range missiles allow for
7958-596: The Atomic Energy Commission for permission to use the Beta calutrons to produce isotopes for physics experiments. Permission was granted, and a wide range of isotopes was produced. Lithium-6 from the Beta calutrons was used for research into thermonuclear weapons . Many other isotopes were used for peaceful scientific and medical purposes. The Beta 3 racetracks were transferred to the ORNL in March 1950. By
8131-402: The Atomic Energy Commission , with the armed forces having only a supporting role. The purpose of the Sandstone tests was also different: they were primarily tests of new bomb designs rather than of the effects of nuclear weapons. Three tests were carried out in April and May 1948 by Joint Task Force 7, with a work force of 10,366 personnel, of whom 9,890 were military. The successful testing of
8304-564: The Clinton Engineer Works in Oak Ridge, Tennessee . By the middle of 1944, there were nearly 1,200 people working at the Radiation Laboratory. Much of the great progress on the electromagnetic process can be attributed to Lawrence's leadership style. His audacity, optimism and enthusiasm were contagious. His staff put in long hours, and University of California administrators sliced through red tape despite not knowing what
8477-797: The Commissariat à l'énergie atomique et aux énergies alternatives in Bruyères-le-Châtel . Israel, Japan and France also built some research calutrons, including the SOLIS and MEIRA separators at the Soreq Nuclear Research Center . There is also CERN 's Isotope Separator On-Line Detector (ISOLDE), which was built in 1967. A calutron at the Saha Institute of Nuclear Physics at Bidhan Nagar in India
8650-948: The Naval Research Laboratory , the Naval Ordnance Laboratory , Argonne National Laboratory , the Aberdeen Proving Ground , the Atomic Energy Commission, Edgerton, Germeshausen & Grier , and other agencies. Each dealt with a different aspect of the tests. The Naval Ordnance Laboratory handled the blast measurement tests, while the Naval Research Laboratory conducted the radiation measurement experiments, and Argonne National Laboratory did gamma ray measurements. Edgerton, Germeshausen, and Grier were contractors hired to design and install
8823-457: The Office of Scientific Research and Development (OSRD), had passed over the electromagnetic method was that while the mass spectrometer was capable of separating isotopes, it produced very low yields. The reason for this was the so-called space charge limitation. Positive ions have positive charge, so they tend to repel each other, which causes the beam to scatter. Drawing on his experience with
SECTION 50
#17327732107418996-695: The Starfish Prime high-altitude nuclear test in 1962, an unexpected effect was produced which is called a nuclear electromagnetic pulse . This is an intense flash of electromagnetic energy produced by a rain of high-energy electrons which in turn are produced by a nuclear bomb's gamma rays. This flash of energy can permanently destroy or disrupt electronic equipment if insufficiently shielded. It has been proposed to use this effect to disable an enemy's military and civilian infrastructure as an adjunct to other nuclear or conventional military operations. By itself it could as well be useful to terrorists for crippling
9169-473: The Treaty on the Non-Proliferation of Nuclear Weapons (1968) attempted to place restrictions on the types of activities signatories could participate in, with the goal of allowing the transference of non-military nuclear technology to member countries without fear of proliferation. Calutron A calutron is a mass spectrometer originally designed and used for separating the isotopes of uranium . It
9342-885: The Trust Territory of the Pacific Islands was a United Nations trust territory administered by the United States, the United Nations Security Council was notified of the upcoming tests on December 2. The atoll was inhabited by the dri-Enewetak, who lived on Aomon, and the dri-Enjebi, who lived on Bijire. Their original homes had been on Enewetak and Enjebi, but they had been moved during the war to make way for military bases. The population, about 140 in number, had been temporarily relocated to Meck Island during Operation Crossroads. This time, Ujelang Atoll , an uninhabited atoll 124 nautical miles (230 km; 143 mi) southwest of Enewetak,
9515-554: The Tsar Bomba (see TNT equivalent ). A thermonuclear weapon weighing as little as 600 pounds (270 kg) can release energy equal to more than 1.2 megatonnes of TNT (5.0 PJ). A nuclear device no larger than a conventional bomb can devastate an entire city by blast, fire, and radiation . Since they are weapons of mass destruction , the proliferation of nuclear weapons is a focus of international relations policy. Nuclear weapons have been deployed twice in war , both by
9688-676: The Tsar Bomba of the USSR, which released an energy equivalent of over 50 megatons of TNT (210 PJ), was a three-stage weapon. Most thermonuclear weapons are considerably smaller than this, due to practical constraints from missile warhead space and weight requirements. In the early 1950s the Livermore Laboratory in the United States had plans for the testing of two massive bombs, Gnomon and Sundial , 1 gigaton of TNT and 10 gigatons of TNT respectively. Fusion reactions do not create fission products, and thus contribute far less to
9861-571: The University of California 's Radiation Laboratory in Berkeley . The two men had met before the war, and were friends. Lawrence was sufficiently impressed to commence his own research into uranium. Uranium-235 makes up only about 0.72% of natural uranium, so the separation factor of any uranium enrichment process needs to be higher than 125 to produce 90% uranium-235 from natural uranium. The Maud Committee had recommended that this be done by
10034-441: The University of Minnesota used a mass spectrometer to create a microscopic amount of enriched uranium-235 in April 1940. John R. Dunning , Aristid von Grosse and Eugene T. Booth were then able to confirm that Bohr was correct. Leo Szilard and Walter Zinn soon confirmed that more than one neutron was released per fission, which made it almost certain that a nuclear chain reaction could be initiated, and therefore that
10207-464: The discovery of nuclear fission by German chemists Otto Hahn and Fritz Strassmann in 1938, and its theoretical explanation by Lise Meitner and Otto Frisch , was brought to the United States by Niels Bohr . Based on his liquid drop model of the nucleus, he theorized that it was the uranium-235 isotope and not the more abundant uranium-238 that was primarily responsible for fission with thermal neutrons . To verify this Alfred O. C. Nier at
10380-424: The hafnium controversy ) have been proposed as possible triggers for conventional thermonuclear reactions. Antimatter , which consists of particles resembling ordinary matter particles in most of their properties but having opposite electric charge , has been considered as a trigger mechanism for nuclear weapons. A major obstacle is the difficulty of producing antimatter in large enough quantities, and there
10553-614: The head of government or head of state . Despite controls and regulations governing nuclear weapons, there is an inherent danger of "accidents, mistakes, false alarms, blackmail, theft, and sabotage". In the late 1940s, lack of mutual trust prevented the United States and the Soviet Union from making progress on arms control agreements. The Russell–Einstein Manifesto was issued in London on July 9, 1955, by Bertrand Russell in
SECTION 60
#173277321074110726-436: The tropopause into the stratosphere , where the calm non-turbulent winds permit the debris to travel great distances from the burst, eventually settling and unpredictably contaminating areas far removed from the target of the explosion. There are other types of nuclear weapons as well. For example, a boosted fission weapon is a fission bomb that increases its explosive yield through a small number of fusion reactions, but it
10899-537: The "implosion" method, is more sophisticated and more efficient (smaller, less massive, and requiring less of the expensive fissile fuel) than the former. A major challenge in all nuclear weapon designs is to ensure that a significant fraction of the fuel is consumed before the weapon destroys itself. The amount of energy released by fission bombs can range from the equivalent of just under a ton to upwards of 500,000 tons (500 kilotons ) of TNT (4.2 to 2.1 × 10 GJ). All fission reactions generate fission products ,
11072-567: The 1217th and 1218th Composite Service Platoons, the 18th Engineer Construction Company and 1219th Signal Service Platoon; Companies D and E of the 2nd Engineer Special Brigade 's 532nd Engineer Boat and Shore Regiment ; the 461st Transportation Amphibious Truck Company; 854th Transportation Port Company; 401st CIC Detachment; and the Naval Shore Base Detachment. As in Operation Crossroads, each detonation
11245-586: The 1980s (though not deployed in Europe) for use as tactical payloads for US Army artillery shells (200 mm W79 and 155 mm W82 ) and short range missile forces. Soviet authorities announced similar intentions for neutron warhead deployment in Europe; indeed, they claimed to have originally invented the neutron bomb, but their deployment on USSR tactical nuclear forces is unverifiable. A type of nuclear explosive most suitable for use by ground special forces
11418-601: The AEC commissioners felt that the news would leak out, and the United States would look secretive. It was therefore decided to make a last minute announcement. There was no announcement of the purpose of the tests, and only cursory press releases. On 18 May, after the series was over, Hull held a press conference in Hawaii, but only permitted the media to quote from written statements. Enjebi, Aomon, and Runit Islands were cleared of vegetation and graded level to make it easier to install
11591-490: The Beta calutrons. Extraordinary efforts were made to recover product, including burning the carbon receiver liners to recover the uranium in them. Despite everything, some 17.4 percent of Alpha product and 5.4 percent of Beta product was lost. Frank Spedding from the Manhattan Project's Ames Laboratory and Philip Baxter from the British Mission were sent to advise on improvements to recovery methods. The death of
11764-725: The Beta racetracks turned out another 953 kilograms enriched to 95 percent by the end of the year. Enriched uranium from the calutrons provided the fissile component of the Little Boy atomic bomb used in the atomic bombing of Hiroshima in August 1945. With the war over, the Alpha tracks began to suspend operations on 4 September 1945, and ceased operation completely on 22 September. The last two Beta tracks went into full operation in November and December 1945, processing feed from K-25 and
11937-605: The British and the Metallurgical Laboratory in Chicago. Other researchers also investigated electromagnetic isotope separation. At Princeton University , a group led by Henry D. Smyth and Robert R. Wilson developed a device known as an isotron. Using a klystron , they were able to separate isotopes using high-voltage electricity rather than magnetism. Work continued until February 1943, when, in view of
12110-681: The China Institute of Atomic Energy in Beijing of identical design to those of the USSR in the early 1960s. In 1945, the British atomic bomb project built a 180° calutron, similar in design to an American Beta calutron, at the Atomic Energy Research Establishment at Harwell, Oxfordshire . Owing to the success of the gaseous diffusion plant at Capenhurst , electromagnetic separation was not pursued by
12283-508: The Clinton Engineer Works. There, special procedures were instituted for handling the silver. When they had to drill holes in it, they did so over paper so that the filings could be collected. After the war, all the machinery was dismantled and cleaned and the floorboards beneath the machinery were ripped up and burned to recover minute amounts of silver. In the end, 155,645.39 troy ounces (4,841.113 kg) or less than 0.036%
12456-425: The Cold War, policy and military theorists considered the sorts of policies that might prevent a nuclear attack, and they developed game theory models that could lead to stable deterrence conditions. Different forms of nuclear weapons delivery (see above) allow for different types of nuclear strategies. The goals of any strategy are generally to make it difficult for an enemy to launch a pre-emptive strike against
12629-494: The Joint Chiefs of Staffs website Publication, "Integration of nuclear weapons employment with conventional and special operations forces is essential to the success of any mission or operation." Because they are weapons of mass destruction, the proliferation and possible use of nuclear weapons are important issues in international relations and diplomacy. In most countries, the use of nuclear force can only be authorized by
12802-578: The Los Alamos National Laboratory, known as J Division, was created specifically to manage nuclear testing. An Atomic Energy Commission group (Task Group 7.1) was responsible for preparing and detonating the nuclear weapons, and conducting the experiments. It consisted of some 283 scientists and technicians responsible for nuclear tests from J Division, the Armed Forces Special Weapons Project ,
12975-466: The Mark 3 Fat Man , an implosion-type nuclear weapon using plutonium . These weapons were not far removed from their laboratory origins. A great deal of work remained to improve ease of assembly, safety, reliability and storage before they were ready for production. There were also many improvements to their performance that had been suggested or recommended during the war that had not been possible under
13148-503: The Nuclear Age (1961) that mere possession of a nuclear arsenal was enough to ensure deterrence, and thus concluded that the spread of nuclear weapons could increase international stability . Some prominent neo-realist scholars, such as Kenneth Waltz and John Mearsheimer , have argued, along the lines of Gallois, that some forms of nuclear proliferation would decrease the likelihood of total war , especially in troubled regions of
13321-717: The Oak Ridge township was selected in the hope that the surrounding ridge lines might contain a major explosion or nuclear accident. Problems with the substratum required the excavation crews to perform more blasting and excavation to provide adequate foundations for the heavy machinery in the facilities. Supplies and materials of all kinds poured in: 2,157 carloads of electrical equipment, 1,219 of heavy equipment, 5,389 of lumber, 1,407 of pipe and fittings, 1,188 of steel, 257 of valves, and 11 of welding electrodes. The racetracks required 85,000 vacuum tubes . Where possible, off-the-shelf components were used, but all too many components of
13494-561: The U.S. nuclear stockpile from 56 bombs in June 1948 to 169 in June 1949. Nuclear weapons were developed during World War II by the Manhattan Project , which created a network of production facilities, and the weapons research and design laboratory at the Los Alamos National Laboratory . Two types of bombs were developed: the Mark 1 Little Boy , a gun-type fission weapon using uranium-235 , and
13667-664: The USAAF detonated a plutonium implosion-type fission bomb nicknamed " Fat Man " over the Japanese city of Nagasaki . These bombings caused injuries that resulted in the deaths of approximately 200,000 civilians and military personnel . The ethics of these bombings and their role in Japan's surrender are to this day, still subjects of debate . Since the atomic bombings of Hiroshima and Nagasaki , nuclear weapons have been detonated over 2,000 times for testing and demonstration. Only
13840-777: The USAF AIR-2 Genie , the AIM-26 Falcon and US Army Nike Hercules . Missile interceptors such as the Sprint and the Spartan also used small nuclear warheads (optimized to produce neutron or X-ray flux) but were for use against enemy strategic warheads. Other small, or tactical, nuclear weapons were deployed by naval forces for use primarily as antisubmarine weapons. These included nuclear depth bombs or nuclear armed torpedoes. Nuclear mines for use on land or at sea are also possibilities. The system used to deliver
14013-618: The United Kingdom, and the calutron was used to separate isotopes for research. The 180° design was not ideal for this purpose, so Harwell built a 90° calutron, HERMES, the "Heavy Elements and Radioactive Material Electromagnetic Separator". It was inspired by France's SIDONIE and PARIS separators at the Laboratoire René Bernas of the University of Paris IX in Orsay , and PARSIFAL at the military research laboratory of
14186-527: The United States against the Japanese cities of Hiroshima and Nagasaki in 1945 during World War II . Nuclear weapons have only twice been used in warfare, both times by the United States against Japan at the end of World War II . On August 6, 1945, the United States Army Air Forces (USAAF) detonated a uranium gun-type fission bomb nicknamed " Little Boy " over the Japanese city of Hiroshima ; three days later, on August 9,
14359-526: The United States. Small, two-man portable tactical weapons (somewhat misleadingly referred to as suitcase bombs ), such as the Special Atomic Demolition Munition , have been developed, although the difficulty of combining sufficient yield with portability limits their military utility. Nuclear warfare strategy is a set of policies that deal with preventing or fighting a nuclear war. The policy of trying to prevent an attack by
14532-579: The calutrons were unique. Two purchasing departments were established, one in Boston near Stone & Webster for facility equipment, and the other at Oak Ridge for construction supplies. The Chief Engineer of the Manhattan District, Colonel James C. Marshall , and his deputy, Lieutenant Colonel Kenneth D. Nichols , discovered that the electromagnetic isotope separation process would require 5,000 short tons (4,500 tonnes) of copper , which
14705-485: The chance of a successful missile defense . Today, missiles are most common among systems designed for delivery of nuclear weapons. Making a warhead small enough to fit onto a missile, though, can be difficult. Tactical weapons have involved the most variety of delivery types, including not only gravity bombs and missiles but also artillery shells, land mines , and nuclear depth charges and torpedoes for anti-submarine warfare . An atomic mortar has been tested by
14878-407: The characteristics of electric discharges in magnetic fields, today known as Bohm diffusion . Their papers on the properties of plasmas under magnetic containment would find usage in the post-war world in research into controlled nuclear fusion . Other technical problems were more mundane but no less important. Although the beams had low intensity, they could, over many hours of operation, still melt
15051-595: The collectors. A water cooling system was therefore added to the collectors and the tank liner. Procedures were developed for cleaning the "gunk" that condensed inside the vacuum tank. A particular problem was blockage of the slits by "crud", which caused the ion beams to lose focus, or stop entirely. The chemists had to find a way of producing quantities of uranium tetrachloride ( UCl 4 ) from uranium oxide . (Nier had used uranium bromide.) Initially, they produced it by using hydrogen to reduce uranium trioxide ( UO 3 ) to uranium dioxide ( UO 2 ), which
15224-592: The construction of five Alpha and two Beta racetracks. In September, he authorized four more Alpha racetracks, which became known as Alpha II, along with two more Beta racetracks to process their product. Construction of the electromagnetic plant at Oak Ridge, codenamed Y-12 , commenced 18 February 1943. The facility would eventually comprise nine major process buildings and 200 other structures covering almost 80 acres (32 ha) of floor space. The 825-acre (334 ha) site in Bear Creek Valley southwest of
15397-663: The contracts with the University of California from the OSRD until 1 May 1943. Major Thomas T. Crenshaw, Jr., became California Area Engineer in August 1942, with Captain Harold A. Fidler , who soon replaced him, as his assistant. Crenshaw established his office in the Donner Laboratory at the University of California. In September 1942, the S-1 Executive Committee recommended that a five-tank pilot plant be built along with
15570-435: The creation of nuclear fallout than fission reactions, but because all thermonuclear weapons contain at least one fission stage, and many high-yield thermonuclear devices have a final fission stage, thermonuclear weapons can generate at least as much nuclear fallout as fission-only weapons. Furthermore, high yield thermonuclear explosions (most dangerously ground bursts) have the force to lift radioactive debris upwards past
15743-455: The decision process. The prospect of mutually assured destruction might not deter an enemy who expects to die in the confrontation. Further, if the initial act is from a stateless terrorist instead of a sovereign nation, there might not be a nation or specific target to retaliate against. It has been argued, especially after the September 11, 2001, attacks , that this complication calls for
15916-537: The development of an atomic bomb was a theoretical possibility. There were fears that a German atomic bomb project would develop one first, especially among scientists who were refugees from Nazi Germany and other fascist countries. At the University of Birmingham in Britain, the Australian physicist Mark Oliphant assigned two refugee physicists—Otto Frisch and Rudolf Peierls —the task of investigating
16089-440: The development of an all-uranium-235 core. By January 1948 the national stockpile contained 50 cores, of which 36 were composite Christy cores, nine were plutonium Christy cores, and five were composite levitated cores. Testing the new levitated, composite and uranium-235 cores would require at least three test firings. More efficient weapons would require less efficient initiators. This meant that less polonium would be required. At
16262-553: The development of an atomic bomb. Britain had offered to give the United States access to its scientific research, so the Tizard Mission 's John Cockcroft briefed American scientists on British developments. He discovered that the American project was smaller than the British, and not as far advanced. A disappointed Oliphant flew to the United States to speak to the American scientists. These included Ernest Lawrence at
16435-457: The electromagnetic plant until September 1942, by which time Lawrence had dropped his objection. The 25 June meeting also designated Stone & Webster as the primary contractor for the design and engineering. The Army assumed responsibility for the Manhattan Project on 17 September 1942, with Brigadier General Leslie R. Groves, Jr. , as director, although the Army did not formally take over
16608-468: The electromagnetic process, $ 18 million (92 percent) was spent at the Radiation Laboratory in Berkeley, and further work conducted at Brown University , Johns Hopkins University and Purdue University , and by the Tennessee Eastman corporation. During 1943, the emphasis shifted from research to development, engineering, and the training of workers to operate the production facilities at
16781-469: The energy of a fission bomb to compress and heat fusion fuel. In the Teller-Ulam design , which accounts for all multi-megaton yield hydrogen bombs, this is accomplished by placing a fission bomb and fusion fuel ( tritium , deuterium , or lithium deuteride ) in proximity within a special, radiation-reflecting container. When the fission bomb is detonated, gamma rays and X-rays emitted first compress
16954-416: The feasibility of an atomic bomb, ironically because their status as enemy aliens precluded their working on secret projects like radar . Their March 1940 Frisch–Peierls memorandum indicated that the critical mass of uranium-235 was within an order of magnitude of 10 kg, which was small enough to be carried by a bomber of the day. The British Maud Committee then unanimously recommended pursuing
17127-500: The first calutron. Its name came from Cal ifornia U niversity and cyclo tron . The work was initially funded by the Radiation Laboratory from its own resources, with a $ 5,000 grant from the Research Corporation . In December Lawrence received a $ 400,000 grant from the S-1 Uranium Committee. The calutron consisted of an ion source, in the form of a box with a slit in it and hot filaments inside. Uranium tetrachloride
17300-455: The fission bomb core. The external method of boosting enabled the USSR to field the first partially thermonuclear weapons, but it is now obsolete because it demands a spherical bomb geometry, which was adequate during the 1950s arms race when bomber aircraft were the only available delivery vehicles. The detonation of any nuclear weapon is accompanied by a blast of neutron radiation . Surrounding
17473-436: The flash and blast as similar to the previous two tests, but this time the base of the condensation cloud was at 2,000 feet (610 m), which gave the observers an unobstructed view of the fireball, which therefore appeared to be brighter and last longer than the other two. Looks were deceiving: its levitated uranium-235 core produced a yield of 18 kilotons. The procedures used in the previous tests were repeated, but this time
17646-420: The fusion fuel, then heat it to thermonuclear temperatures. The ensuing fusion reaction creates enormous numbers of high-speed neutrons , which can then induce fission in materials not normally prone to it, such as depleted uranium . Each of these components is known as a "stage", with the fission bomb as the "primary" and the fusion capsule as the "secondary". In large, megaton-range hydrogen bombs, about half of
17819-437: The gaseous diffusion process, uranium tetrachloride is hygroscopic , so work with it had to be undertaken in gloveboxes that were kept dry with phosphorus pentoxide ( P 4 O 10 ). The presence of phosgene, a lethal gas responsible for 85,000 deaths as a chemical weapon during World War I , required that the chemists wear gas masks when handling it. Of the $ 19.6 million spent on research and development of
17992-550: The gaseous diffusion process. Uranium enriched to about 40 percent uranium-235 was brought to Sverdlovsk-45 for final enrichment to between 92 and 98 percent. After the problems with the gaseous diffusion process were resolved in 1950, it was decided not to proceed with a full-scale electromagnetic plant. As of 2009 , it remains operational. In 1969, a research calutron known as S-2 was built at Arzamas-16 for high-efficiency separation of isotopes of heavy elements like plutonium. Four research and production calutrons were built at
18165-535: The globe, would make all life on the planet extinct. In connection with the Strategic Defense Initiative , research into the nuclear pumped laser was conducted under the DOD program Project Excalibur but this did not result in a working weapon. The concept involves the tapping of the energy of an exploding nuclear bomb to power a single-shot laser that is directed at a distant target. During
18338-413: The greater success of the calutron, work was discontinued and the team was transferred to other duties. At Cornell University a group under Lloyd P. Smith that included William E. Parkins, and A. Theodore Forrester devised a radial magnetic separator. They were surprised that their beams were more precise than expected, and, like Lawrence, deduced that it was a result of stabilization of the beam by air in
18511-553: The largest nuclear detonation up to that time, but it was considered inefficient and wasteful of the fissile material. Zebra, the third test, and the last of the Sandstone series, was detonated on Runit just before sunrise at 06:04 on May 15, 1948. This test was characterized by AEC Chairman David Lilienthal as the "hardest and most important" test of the three. By using one of the B-class initiators, it demonstrated that these could still be used with confidence. The observers perceived
18684-496: The majority of their energy from nuclear fission reactions alone, and those that use fission reactions to begin nuclear fusion reactions that produce a large amount of the total energy output. All existing nuclear weapons derive some of their explosive energy from nuclear fission reactions. Weapons whose explosive output is exclusively from fission reactions are commonly referred to as atomic bombs or atom bombs (abbreviated as A-bombs ). This has long been noted as something of
18857-400: The men who had carried out the procedure for Yoke was then also found to have burns on his hands and was hospitalized too, but was discharged on 28 May. Once again the drone tank gave trouble, and bogged in the crater, but the soil samples were retrieved by the backup drone tank. Both tanks were subsequently dumped in the ocean. The successful testing of the new cores in the Sandstone tests had
19030-496: The mid-1950s, the Beta calutrons had produced quantities of all the naturally occurring stable isotopes except those of osmium , which had to wait until April 1960. The calutrons continued to produce isotopes until 1998. As of 2015 , they are still on standby. Like the United States, the Soviet Union (USSR) carried out research on multiple enrichment technologies for the Soviet atomic bomb project . A trial electromagnetic process
19203-407: The midst of the Cold War. It highlighted the dangers posed by nuclear weapons and called for world leaders to seek peaceful resolutions to international conflict. The signatories included eleven pre-eminent intellectuals and scientists, including Albert Einstein , who signed it just days before his death on April 18, 1955. A few days after the release, philanthropist Cyrus S. Eaton offered to sponsor
19376-545: The military establishment have questioned the usefulness of such weapons in the current military climate. According to an advisory opinion issued by the International Court of Justice in 1996, the use of (or threat of use of) such weapons would generally be contrary to the rules of international law applicable in armed conflict, but the court did not reach an opinion as to whether or not the threat or use would be lawful in specific extreme circumstances such as if
19549-408: The missiles before they land or implementing civil defense measures using early-warning systems to evacuate citizens to safe areas before an attack. Weapons designed to threaten large populations or to deter attacks are known as strategic weapons . Nuclear weapons for use on a battlefield in military situations are called tactical weapons . Critics of nuclear war strategy often suggest that
19722-460: The most important being that they had four sources instead of just two. They also had improved magnets and vacuum systems. Tennessee Eastman was hired to manage Y-12 on the usual cost plus fixed fee basis, with a fee of $ 22,500 per month plus $ 7,500 per racetrack for the first seven racetracks and $ 4,000 per additional racetrack. Workers were recruited in the Knoxville area. The typical recruit
19895-480: The neutrons its fission produces. On the other hand, the slower reaction of uranium-235 permits the assembly of super-critical masses, making it theoretically possible to produce weapons with high yields. By July 1945, Oppenheimer and Groves were considering using both materials in a composite core containing 3.25 kilograms (7.2 lb) of plutonium and 6.5 kilograms (14 lb) of uranium-235. The composite cores became available in 1946. Los Alamos' priority then became
20068-476: The new cores in the Operation Sandstone tests rendered every component of the old weapons obsolete. Even before the third test had been carried out, production of the old cores was halted, and all effort concentrated on the new Mark 4 nuclear bomb , which would become the first mass-produced nuclear weapon. More efficient use of fissionable material as a result of Operation Sandstone would increase
20241-477: The new K-27 gaseous diffusion plant. By May 1946, studies suggested that the gaseous diffusion plants could fully enrich the uranium by themselves without accidentally creating a critical mass. After a trial demonstrated that this was the case, Groves ordered all but one Beta track shut down in December 1946. The total cost of the electromagnetic project up to the end of the Manhattan Project on 31 December 1946
20414-498: The old Beta chemistry building, 9203, was converted into a laboratory. Work started on the new Alpha II process buildings on 2 November 1943; the first racetrack was completed in July 1944, and all four were operational by 1 October 1944. The Alpha II racetracks were configured in a linear layout rather than an oval, although they were still called racetracks. In all, there were 864 Alpha calutrons, arranged in nine racetracks of 96. There were only 36 calutrons in each Beta racetrack, for
20587-453: The precise control of charged-particle beams from his work with his invention, the cyclotron , Lawrence suspected that the air molecules in the vacuum chamber would neutralize the ions, and create a focused beam. Oliphant inspired Lawrence to convert his old 37-inch (94 cm) cyclotron into a giant mass spectrometer for isotope separation . The 37-inch cyclotron at Berkeley was dismantled on 24 November 1941, and its magnet used to create
20760-477: The preliminary designs for a production plant to Stone & Webster before the end of the year, but one important issue remained unsettled. Oppenheimer contended that weapons-grade uranium would have to be 90% pure uranium-235. Edward Lofgren and Martin Kamen thought that this could not be achieved without a second stage of enrichment. The two stages became known as Alpha and Beta. In March 1943, Groves approved
20933-513: The pressure of wartime development. Norris Bradbury , who replaced Robert Oppenheimer as director at Los Alamos, felt that "we had, to put it bluntly, lousy bombs." Plutonium was produced by irradiating uranium-238 in three 250 MW nuclear reactors at the Hanford site . In theory they could produce 0.91 grams (0.032 oz) of plutonium per megawatt-day, or about 20 kilograms (44 lb) per month. In practice, production never approached such
21106-440: The production (by irradiation of bismuth-209 ) of polonium-210 , which was used in the initiators , a critical component of the nuclear weapons. Some 62 kilograms (137 lb) of bismuth-209 had to be irradiated for 100 days to produce 600 curies of polonium-210, a little over 132 milligrams (2.04 gr). Because polonium-210 has a half-life of only 138 days, at least one reactor had to be kept running. The oldest unit, B pile,
21279-517: The project was about. Government officials began to view the development of atomic bombs in time to affect the outcome of the war as a genuine possibility. Vannevar Bush , the director of the OSRD, which was overseeing the project, visited Berkeley in February 1942, and found the atmosphere there "stimulating" and "refreshing". On 9 March 1942, he reported to the president, Franklin D. Roosevelt , that it might be possible to produce enough material for
21452-428: The remains of the split atomic nuclei. Many fission products are either highly radioactive (but short-lived) or moderately radioactive (but long-lived), and as such, they are a serious form of radioactive contamination . Fission products are the principal radioactive component of nuclear fallout . Another source of radioactivity is the burst of free neutrons produced by the weapon. When they collide with other nuclei in
21625-426: The required instrumentation, and a causeway was built between Aomon and Bijire so the instrument cables could be run from the test tower on Aomon to the control station on Bijire. The detonations were ordered so that later test areas would suffer minimal fallout from the earlier shots. The Army component, Task Group 7.2, was responsible for construction work. It consisted of the 1220th Provisional Engineer Battalion, with
21798-484: The same electric charge but different masses, the heavier isotopes are deflected less by the magnetic field, causing the beam of particles to separate into several beams by mass, striking the plate at different locations. The mass of the ions can be calculated according to the strength of the field and the charge of the ions. During World War II , calutrons were developed to use this principle to obtain substantial quantities of high-purity uranium-235, by taking advantage of
21971-515: The same time, new production plants were coming online and the Wigner effect problem had been solved. By May 1951, plutonium production was twelve times that of 1947, while uranium-235 production had increased eight-fold. The Chief of the Armed Forces Special Weapons Project , Major General Kenneth D. Nichols , saw clearly that the era of scarcity was over. He now "recommended that we should be thinking in terms of thousands of weapons rather than hundreds." Nuclear weapon A nuclear weapon
22144-417: The shape of a racetrack; hence the name. The two Alpha I buildings, 9201-1 and 9201-2, each contained two racetracks, with only one in the Alpha I 1 ⁄ 2 , 9201-3. The Beta racetracks were smaller, linear in shape, and optimized for recovery rather than production, with only 36 instead of 96 process bins. The four Alpha II racetracks were also linear in configuration. They incorporated many improvements,
22317-468: The small mass difference between uranium isotopes. Electromagnetic separation for uranium enrichment was abandoned in the post-war period in favor of the more complicated, but more efficient, gaseous diffusion method. Although most of the calutrons of the Manhattan Project were dismantled at the end of the war, some remained in use to produce isotopically enriched samples of naturally occurring elements for military, scientific and medical purposes. News of
22490-432: The spherical symmetry of the implosion. The Theoretical Division at Los Alamos, known as T Division, had run computer calculations on the levitated core as early as March 1945. The use of the levitated core had been proposed during the planning for Operation Crossroads, but it had been decided instead to use the existing solid core "Christy" design. This was named after its designer, Robert Christy . For Sandstone, however, it
22663-402: The surrounding material, the neutrons transmute those nuclei into other isotopes, altering their stability and making them radioactive. The most commonly used fissile materials for nuclear weapons applications have been uranium-235 and plutonium-239 . Less commonly used has been uranium-233 . Neptunium-237 and some isotopes of americium may be usable for nuclear explosives as well, but it
22836-498: The survival of the state were at stake. Another deterrence position is that nuclear proliferation can be desirable. In this case, it is argued that, unlike conventional weapons, nuclear weapons deter all-out war between states, and they succeeded in doing this during the Cold War between the U.S. and the Soviet Union . In the late 1950s and early 1960s, Gen. Pierre Marie Gallois of France, an adviser to Charles de Gaulle , argued in books like The Balance of Terror: Strategy for
23009-489: The tamper, there would be an air gap between the tamper and the core, which would be suspended inside on wires. This would allow the tamper to gain more momentum before striking the core. The principle was similar to swinging a hammer at a nail versus putting the hammerhead directly on the nail and pushing as hard as possible. In order for this to work outside the laboratory, the wires had to be strong enough to withstand being dropped from an aircraft, but thin enough to not disturb
23182-592: The tests. They readily agreed that they would be scientific in nature, with Los Alamos supplying the technical direction and the armed forces providing supplies and logistical support. The cost of the tests, around $ 20 million, was divided between the Department of Defense and the Atomic Energy Commission. Lieutenant General John E. Hull was designated as test commander. Rear Admiral William S. Parsons and Major General William E. Kepner reprised their Operation Crossroads roles as deputy commanders. Joint Task Force 7
23355-399: The third and first Alpha racetracks, now repaired, became operational in March 1944, and the fourth Alpha racetrack in April 1944. A third building, 9201-3, contained a fifth racetrack that incorporated some modifications, and was known as Alpha I 1 ⁄ 2 . This became operational on 3 June 1944. Work on the Alpha and Beta chemistry buildings, 9202 and 9203, commenced in February 1943, and
23528-651: The time of Sandstone, the national stockpile of polonium-beryllium initiators consisted of 50 A-Class initiators, with more than 25 curies of polonium, and 13 B-Class initiators with 12 to 25 curies. During Sandstone, at least one test would be conducted with a B-Class initiator. The tests were authorized by President Harry S. Truman on June 27, 1947. The Atomic Energy Commission's Director of Military Applications, Brigadier General James McCormack and his deputy, Captain James S. Russell , met with Bradbury and John Henry Manley at Los Alamos on July 9 to make arrangements for
23701-487: The timing and firing systems. Seven experimental weapon assemblies and six cores were delivered to San Pedro, California , and loaded on the weapon assembly ship USS Curtiss , in February 1948, but the Atomic Energy Commission only gave permission for the expenditure of three cores in the tests. The naval forces were organized as Task Group 7.3. It consisted of: Source: Berkhouse et al , Operation Sandstone , p. 40 In September 1947, Hull, Russell, who
23874-408: The top and bottom of the vacuum tank. The effect of the shims was to slightly increase the magnetic field in such a way as to help focus the ion beam. Work would continue on the shims through 1943. The main calutron patents were Methods of and apparatus for separating materials (Lawrence), Magnetic shims (Oppenheimer and Frankel), and Calutron system (Lawrence). Burhop and Bohm later studied
24047-486: The trainees were not informed of the purpose of the equipment they were taught to operate. The calutrons were initially operated by scientists from Berkeley to remove bugs and achieve a reasonable operating rate. Then the Tennessee Eastman operators took over. Nichols compared unit production data, and pointed out to Lawrence that the young "hillbilly" girl operators were outproducing his Ph.Ds. They agreed to
24220-570: The vacuum chamber. In February 1942, their team was consolidated with Lawrence's in Berkeley. While the process had been demonstrated to work, considerable effort was still required before a prototype could be tested in the field. Lawrence assembled a team of physicists to tackle the problems, including David Bohm , Edward Condon , Donald Cooksey , A. Theodore Forrester, Irving Langmuir , Kenneth Ross MacKenzie , Frank Oppenheimer , J. Robert Oppenheimer , William E. Parkins, Bernard Peters and Joseph Slepian . In November 1943 they were joined by
24393-446: The weapon system and difficult to defend against the delivery of the weapon during a potential conflict. This can mean keeping weapon locations hidden, such as deploying them on submarines or land mobile transporter erector launchers whose locations are difficult to track, or it can mean protecting weapons by burying them in hardened missile silo bunkers. Other components of nuclear strategies included using missile defenses to destroy
24566-453: The winch cable snagged, and the test samples had to be retrieved by a jeep, exposing its crew to more radiation. The Los Alamos personnel assigned to remove the filters from the B-17 drones had apparently carried out the procedure on X-Ray and Yoke without problems, but this time three of them suffered radiation burns on their hands serious enough to be hospitalized and need skin grafting . One of
24739-631: The world where there exists a single nuclear-weapon state. Aside from the public opinion that opposes proliferation in any form, there are two schools of thought on the matter: those, like Mearsheimer, who favored selective proliferation, and Waltz, who was somewhat more non- interventionist . Interest in proliferation and the stability-instability paradox that it generates continues to this day, with ongoing debate about indigenous Japanese and South Korean nuclear deterrent against North Korea . The threat of potentially suicidal terrorists possessing nuclear weapons (a form of nuclear terrorism ) complicates
24912-624: The yield comes from the final fissioning of depleted uranium. Virtually all thermonuclear weapons deployed today use the "two-stage" design described to the right, but it is possible to add additional fusion stages—each stage igniting a larger amount of fusion fuel in the next stage. This technique can be used to construct thermonuclear weapons of arbitrarily large yield. This is in contrast to fission bombs, which are limited in their explosive power due to criticality danger (premature nuclear chain reaction caused by too-large amounts of pre-assembled fissile fuel). The largest nuclear weapon ever detonated,
25085-611: Was $ 673 million (equivalent to $ 10.5 billion in 2023). The workforce at Y-12 dropped from a wartime peak of 22,482 on 21 August 1945 to less than 1,700 in 1949. All the calutrons were removed and dismantled, except for the XAX and XBX training tracks in Building 9731, and the Beta 3 racetracks in Building 9204–3. In 1947, Eugene Wigner , the director of the Oak Ridge National Laboratory (ORNL), asked
25258-438: Was 25% or more. This was somewhat higher than Los Alamos' prediction. Observers watching from ships in the lagoon saw a brilliant flash and felt the radiant heat. A condensation cloud 5 nautical miles (9.3 km; 5.8 mi) in diameter quickly enveloped the fireball, which glowed within the cloud. It took 45 to 50 seconds for the thunderous roar of the explosion to reach the observers. About 20 minutes later, Bairoko launched
25431-545: Was a young woman, a recent graduate of a local high school. Training was initially conducted at the University of Tennessee . Training switched to Berkeley from April to September 1943, where it was conducted on the XA calutron and a 1:16 scale model of the Alpha racetrack, and then to Oak Ridge when the XAX calutron became available. Some 2,500 operators would be required once all the Alpha II calutrons were available. The Tennessee Eastman payroll at Y-12 ballooned from 10,000 in mid-1944 to 22,482 in August 1945. For security reasons,
25604-458: Was affected by fallout, but were not required. Unlike the Crossroads tests, which were conducted in the media spotlight, the Sandstone tests were carried out with minimal publicity. On April 15, there was still discussion in Washington about whether or not there should be any public announcement of the tests at all. Hull opposed making any announcement until after the series was completed, but
25777-425: Was authorized on 2 April 1945 and was completed by 1 December 1945. A new group of Alpha chemistry buildings known as the 9207 group was commenced in June 1944, but work was halted in June 1945 before they were completed. Along with these main buildings, there were offices, workshops, warehouses and other structures. There were two steam plants for heating, and a power plant for electricity. The Alpha racetracks were
25950-444: Was carried out in 1946 with a calutron using a magnet taken from Germany. A site was chosen for an electromagnetic plant at Sverdlovsk-45 in 1946. The pilot plant, known as Plant 418, was completed in 1948. A more efficient design was developed in which the particle beams were bent by 225° instead of 180° as in the American calutron. It was used to complete the uranium enrichment process after technical difficulties were encountered with
26123-484: Was completed in September. Work on the Beta process building, 9204-1, began in May 1943, and was ready for operation on 13 March 1944, but was not completed until September 1944. Groves authorized Alpha II in September 1943. This consisted of two new Alpha process buildings, 9201-4 and 9201-5, another Beta, 9204-2, an extension to the Alpha chemistry building, and a new Beta chemistry building, 9206. When 9206 opened,
26296-436: Was decided that at least two of the three tests would use levitated cores. The motivation behind the composite core was to make better use of the available fissionable material. The use of uranium-235 in an implosion weapon instead of the inefficient gun type Little Boy was an obvious development. However, while plutonium was more expensive and harder to produce than uranium-235, it fissions faster, because it makes better use of
26469-693: Was designated test director on October 14, and Joint Task Force 7's scientific director, Darol K. Froman from the Los Alamos Laboratories, set out with a group of scientists and military officers to examine various proposed test sites in the Pacific. Enewetak Atoll was chosen as the test site on October 11. The island was remote, but with a good harbor and an airstrip. It also had ocean currents and trade winds that would carry fallout out to sea, an important consideration in view of what had happened at Bikini Atoll during Operation Crossroads. As
26642-515: Was detonated on Aomon just before sunrise on May 1, 1948, at 06:09, a day late due to unfavorable winds. The observers saw a similar flash and felt the same heat as the X-Ray blast, but the 6-nautical-mile (11 km; 6.9 mi) wide condensation cloud was larger, and the sound of the explosion more forceful. One observer likened it to the sound of "a paper bag which is forcefully burst in a small room". They were correct: its yield of 49 kilotons made it
26815-443: Was developed by Ernest Lawrence during the Manhattan Project and was based on his earlier invention, the cyclotron . Its name was derived from California University Cyclotron, in tribute to Lawrence's institution, the University of California , where it was invented. Calutrons were used in the industrial-scale Y-12 uranium enrichment plant at the Clinton Engineer Works in Oak Ridge, Tennessee . The enriched uranium produced
26988-610: Was formally activated on October 18, 1947. As its commander, Hull was answerable to both the Joint Chiefs of Staff and the Atomic Energy Commission. Joint Task Force 7 consisted of 10,366 personnel, 9,890 of them military. Its headquarters consisted of about 175 men, of whom 96 were on board the USS ; Mount McKinley . The rest were accommodated on the USS ; Albemarle , Curtiss and Bairoko . A special division of
27161-567: Was given its own code name, taken from the Joint Army/Navy Phonetic Alphabet . All used modified Mark III assemblies, and were detonated from 200-foot (61 m) towers. The timing of the detonations was a matter of compromise. The gamma ray measurement experiments required darkness, but the Boeing B-17 Flying Fortress drones that would sample the clouds needed daylight to control them. As
27334-642: Was in desperately short supply. However, they realized that silver could be substituted, in an 11:10 ratio of copper:silver. On 3 August 1942, Nichols met with the Under Secretary of the Treasury , Daniel W. Bell , and asked for the transfer of silver bullion from the West Point Bullion Depository . Nichols later recalled the conversation: He explained the procedure for transferring the silver and asked, "How much do you need?" I replied, "Six thousand tons." 'How many troy ounces
27507-467: Was in the form of uranium hexafluoride ( UF 6 ). It was converted to uranium trioxide, which then went into the usual process for conversion to uranium tetrachloride. On 5 August 1945, K-25 started producing feed enriched to 23 percent, enough to be fed straight into the Beta racetracks. The remaining Alpha product was then fed into K-25. By September 1945, the calutrons had produced 88 kilograms of product with an average enrichment of 84.5 percent, and
27680-499: Was ionized by the filament, and then passed through a 0.04-by-2-inch (1.0 by 50.8 mm) slot into a vacuum chamber. The magnet was then used to deflect the ion beam by 180°. The enriched and depleted beams went into collectors. When the calutron was first operated on 2 December 1941, just days before the Japanese attack on Pearl Harbor brought the United States into World War II , a uranium beam intensity of 5 microamperes (μA)
27853-407: Was lost. In May 1970, the last 67 short tons (61 tonnes; 2,000,000 troy ounces) of silver was replaced with copper and returned to the Treasury. The XAX racetrack with two tanks and three coils was ready to train workers in August 1943. Bugs were discovered, but were not aggressively followed up. The first Alpha process building, 9201-1, was completed on 1 November 1943. When the first racetrack
28026-408: Was made on 11 May 1944. On 7 June 1944, Y-12 made its first delivery of weapons-grade Beta product, enriched to as high as 89% uranium-235. A major problem was that of loss of feed material and product. Only 1 part in 5,825 of the feed material became finished product. About 90 percent was splattered over the feed bottles or vacuum tanks. The problem was particularly acute with the enriched feed of
28199-473: Was only enough for one of the very wasteful Little Boys. A Fat Man was 17.5 times as efficient as a Little Boy, but a ton of uranium ore could yield eight times as much uranium-235 as plutonium, and on a per-gram basis, plutonium cost somewhere between four and eight times as much to produce as uranium-235, which at this time cost around $ 26 per gram. The objectives of the Sandstone series of tests were to: Levitation meant that instead of being immediately inside
28372-430: Was received by the collector. Lawrence's hunch about the effect of the air molecules in the vacuum chamber was confirmed. A nine-hour run on 14 January 1942 with a 50 μA beam produced 18 micrograms (μg) of uranium enriched to 25% uranium-235, about ten times as much as Nier had produced. By February, improvements in the technique allowed it to generate a 1,400 μA beam. That month, 75 μg samples enriched to 30% were shipped to
28545-412: Was selected as a relocation site. A Naval Construction Battalion group arrived there on November 22 to build accommodation and amenities. The military authorities met with the local chiefs on December 3, and they agreed to the relocation, which was carried out by USS King County by December 20. An LST and four Douglas C-54 Skymaster aircraft were placed on standby to evacuate Ujelan in case it
28718-420: Was started up for testing on schedule in November, the 14-ton vacuum tanks crept out of alignment by as much as 3 inches (8 cm) because of the power of the magnets and had to be fastened more securely. A more serious problem arose when the magnetic coils started shorting out. In December Groves ordered a magnet broken open, and handfuls of rust were found inside. Moisture was also a problem in its own right, as
28891-433: Was that the beams interfered with each other, producing a series of oscillations called hash. An arrangement was devised that minimized the interference, resulting in reasonably good beams being produced, in September 1942. Robert Oppenheimer and Stan Frankel invented the magnetic shim , a device used to adjust the homogeneity of a magnetic field. These were sheets of iron about 3 feet (1 m) in width that were bolted to
29064-744: Was the Special Atomic Demolition Munition , or SADM, sometimes popularly known as a suitcase nuke . This is a nuclear bomb that is man-portable, or at least truck-portable, and though of a relatively small yield (one or two kilotons) is sufficient to destroy important tactical targets such as bridges, dams, tunnels, important military or commercial installations, etc. either behind enemy lines or pre-emptively on friendly territory soon to be overtaken by invading enemy forces. These weapons require plutonium fuel and are particularly "dirty". They also demand especially stringent security precautions in their storage and deployment. Small "tactical" nuclear weapons were deployed for use as antiaircraft weapons. Examples include
29237-586: Was the winding of the wire, which was too tight. Groves ordered the racetracks to be torn down and the magnets sent back to the factory to be cleaned and rewound. Rigid standards for preparation and cleanliness were instituted to prevent a recurrence of these problems. Training for the Beta tracks shifted from the XAX to the XBX training and development racetrack in November 1943. A second Alpha I racetrack became operational in January 1944. The first Beta racetrack and
29410-422: Was then reacted with carbon tetrachloride ( CCl 4 ) to produce uranium tetrachloride. Charles A. Kraus proposed a better method for large-scale production that involved reacting the uranium oxide with carbon tetrachloride at high temperature and pressure. This produced uranium pentachloride ( UCl 5 ) and phosgene ( COCl 2 ). While nowhere near as nasty as the uranium hexafluoride used by
29583-563: Was therefore closed down so that it would be available in the future. Investigation of the problem would take most of 1946 before a fix was found. Uranium-235 was derived from enrichment of natural uranium at the Y-12 plant and K-25 site in Oak Ridge, Tennessee. Improvements in the processes and procedures of the electromagnetic and gaseous isotope separation between October 1945 and June 1946 led to an increase in production to around 69 kilograms (152 lb) of uranium-235 per month, which
29756-407: Was used in the Little Boy atomic bomb that was detonated over Hiroshima on 6 August 1945. The calutron is a type of sector mass spectrometer , an instrument in which a sample is ionized and then accelerated by electric fields and deflected by magnetic fields . The ions ultimately collide with a plate and produce a measurable electric current . Since the ions of the different isotopes have
29929-470: Was used to produce plutonium for India's first nuclear test on 18 May 1974. After the 1990–91 Gulf War , UNSCOM determined that Iraq had been pursuing a calutron program to enrich uranium. Iraq chose to develop the electromagnetic process over more modern, economic, and efficient methods of enrichment because calutrons were easier to build, with fewer technical challenges, and the components required to build them were not subject to export controls. At
#740259