When was the first thermonuclear weapon developed?
Violet Club
In 1953, shortly after the Americans tested a thermonuclear weapon in 1952, followed by the Soviets with Joe 4, and before the UK government took a decision in July 1954 to develop a thermonuclear weapon, the Atomic Weapons Research Establishment at Aldermaston was asked about the possibilities for a very large pure fission bomb with a yield of one megaton. This study referred to the Zodiak Mk.3 bomb, but progressed no further than a rudimentary study. At this time studies were also started that ultimately led to a decision in 1954 to develop a thermonuclear weapon, and the design studies were split into two tracks because the British at that time had not yet discovered the Teller-Ulam technique necessary to initiate fusion. One track led to an intermediate design, the so-called Type A thermonuclear design, similar to the Alarm Clock and layer cake hybrid designs of other nuclear powers; although these designs are now regarded as large boosted fission weapons, and no longer regarded as thermonuclear weapons that derive a very large part of their energy from a fusion reaction, designated by the British as Type B, but as hybrids. The British hybrid weapon was known as Green Bamboo, weighed approx 4,500 lb (2,045 kg) and its spherical shape measured approx 45 inches diameter with a 72-point implosion system. This Green Bamboo weapon was intended as the warhead for all projected British strategic delivery systems of the period; the Yellow Sun Stage 1 air-dropped bomb, and the Blue Steel air-launched stand-off missile. The large girth of these weapons was designed to accommodate the diameter of Green Bamboo's implosion sphere.
Project Grab Bag
The first nuclear detonation was an above-ground test, “Trinity”, conducted in New Mexico on July 16, 1945. It represented an important accomplishment of the Manhattan Project that had been initiated at Los Alamos National Laboratory in 1943. In less than two months following this test, nuclear weapons assembled at Los Alamos were used in the Pacific War against Japan. Hiroshima was devastated on August 6, 1945 with a uranium-235 gun device with a fission product yield of about 15 kilotons. Three days later, on August 9, 1945, a plutonium-239 implosion device with a yield of about 22 kilotons was detonated over Nagasaki. These events significantly influenced the conclusion of World War II as the incredibly destructive power of these new weapons became apparent. The Manhattan Project brought together scientists from the US and Britain to collaborate on this nuclear weapons development program. Los Alamos was the epicenter of this activity, and, in spite of high-level security, it was realized in 1948 that security of the program had been breached. Klaus Fuchs, a British theoretical physicist intimately involved in some of the most sensitive aspects of the program, had supplied the USSR with key information via outside contacts beginning in 1945. This information substantially advanced the Soviet effort in developing nuclear weapons. As the US became aware of the loss of key ideas and design concepts, it was important to reassess the state of the Soviet program in fission devices, and to monitor extensions of their program to fusion devices. One concern was the extent of progress made by the Soviets in producing fissionable material through reactor operations. Of even greater importance was the state of development of fission-fusion devices capable of orders of magnitude greater destructive power than the fission devices used against Japan.
Mark 16 nuclear bomb
By April 1954 they were all retired, as the alternative solid-fueled thermonuclear weapons had been tested successfully. These solid fuel thermonuclear bombs were far easier to handle, requiring no cryogenic temperature materials or cooling system. It was replaced with the five EC-14 weapons brought up to an acceptable standard as the TX-14 and production Mark 17 nuclear bombs in mid-1954.
France and weapons of mass destruction
A total of 193 nuclear tests were carried out in Polynesia from 1966 to 1996. On 24 August 1968 France detonated its first thermonuclear weapon—codenamed Canopus—over Fangataufa. A fission device ignited a lithium-6 deuteride secondary inside a jacket of highly enriched uranium to create a 2.6 megaton blast.
Igor Kurchatov
The third stage of Kurchatov's work began at the end of 1949. Kurchatov was handling with being a scientific leader of the project to perfect nuclear weapons and create hydrogen weapons and also being a scientist with a vision to build the foundation for the future advance of nuclear science and engineering. The first group of researchers that helped solve the problem to find a unique design of a nuclear-thermonuclear weapon was led by Sakharov Puff in 1953 known as RDS-6 these group members were I.E. Tamm, Z.S. Belenky, V.L. Ginzburg, A.D. Sakharov, Yu.A. Romanov, and I.Ya. Pomeranchuk, V.N. Klimov, N.N. Bogolyubov, and D.V. Shirkov. Later, a joint team headed by Khariton discovered the basic physical principle of modern thermonuclear weapons, radiation implosion, and carried out a successful test in 1955 the team included: Ya.B. Zel'dovich, Yu.A. Trut- nev, and Sakharov. Achieving these scientific discoveries effectively solved the strategic task of securing the Soviet Union's nuclear similarity with the United States. It created a basis to stop the atomic race, both sides started to lean towards political solutions that could lead to the discontinuance of the nuclear race and cessation of nuclear tests, and Kurchatov was also a necessity to that step.
Nuclear weapons and the United Kingdom
The Green Granite prototype, known as Short Granite, was tested in the first of the Operation Grapple test series, Grapple 1. The bomb was dropped from a height of by a Vickers Valiant piloted by Wing Commander Kenneth Hubbard, off the shore of Malden Island in the Pacific on 15 May 1957. It was Britain's second airdrop of a nuclear bomb after the Operation Buffalo test at Maralinga on 11 October 1956, and the first of a thermonuclear weapon. The United States had not attempted an airdrop of a hydrogen bomb until the Operation Redwing Cherokee test on 21 May 1956. Short Granite's yield was estimated at , far below its designed capability. Despite its failure, the test was hailed as a successful thermonuclear explosion, and the government did not confirm or deny reports that the UK had become a third thermonuclear power. When documents on the series began to be declassified in the 1990s, they were denounced as a hoax. The reports were unlikely to have fooled the American observers.
Nuclear weapon
Virtually all thermonuclear weapons deployed today use the "two-stage" design described above, 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, in contrast to fission bombs, which are limited in their explosive force. The largest nuclear weapon ever detonated, the Tsar Bomba of the USSR, which released an energy equivalent of over , was a three-stage weapon. Most thermonuclear weapons are considerably smaller than this, due to practical constraints from missile warhead space and weight requirements.
Fusion reactions do not create fission products, and thus contribute far less to 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.
British hydrogen bomb programme
A New Weapons Committee was established at Aldermaston on 15 October 1951 to examine improvements to their atomic bombs. John Corner, the head of the theoretical group at Aldermaston, suggested producing a device in the "megaton range"—one with a yield of or more. In this he was thinking not of a thermonuclear weapon, but of a large fission one. The idea was not pursued at that time, because the RAF wanted more, not bigger, atomic bombs. Meeting in Bermuda in December 1953 with Dwight D. Eisenhower, who had replaced Truman as president earlier that year, Churchill told him that the RAF had reckoned that fission bombs would be sufficient for most targets, and therefore that Britain had no intention of developing hydrogen bombs.
On 12 and 19 March 1954, Penney briefed the Gen 475 Committee meetings, attended by the Chiefs of Staff, senior officials from the Ministry of Defence and Foreign Office, and Sir Edwin Plowden, about recent developments in thermonuclear weapons. Sir Frederick Brundrett, the chairman of the Chiefs of Staff's Working Party on the Operational Use of Atomic Weapons (OAW), then asked Penney on 25 May for a working paper for an OAW meeting on 31 May. In turn, OAW sent a report to the Chiefs of Staff, who recommended that the United Kingdom develop its own thermonuclear weapons. Admiral of the Fleet Sir Rhoderick McGrigor, the First Sea Lord, recalled that:
Armed Forces Special Weapons Project
Nuclear weapons were developed during World War II by the Manhattan Project, a major research and development effort led by the United States, with participation from the United Kingdom and Canada. From 1942 to 1946, it was under the direction of Major General Leslie R. Groves, Jr., of the US Army Corps of Engineers. It created a network of production facilities, most notably for uranium enrichment at Oak Ridge, Tennessee, plutonium production at Hanford, Washington and weapons research and design at the Los Alamos Laboratory in Los Alamos, New Mexico. The nuclear weapons that were developed were used in the atomic bombings of Hiroshima and Nagasaki in August 1945.
Nuclear weapons and the United Kingdom
By 1949, international control of atomic weapons seemed almost impossible to achieve, and Truman proposed to the Joint Committee on Atomic Energy in July a "full partnership" with Britain in exchange for uranium; negotiations between the two countries began that month. While the first Soviet atomic bomb test in August 1949 was embarrassing to the British (who had not expected a Soviet atomic weapon until 1954) for having been beaten, it was for the Americans another reason for cooperation. Although they would soon have their own nuclear capability, the British proposed that instead of building their own uranium-enrichment plant they would send most of their scientists to work in the US, and swap plutonium from Windscale for enriched uranium from the US. While Britain would not formally give up building or researching its own weapons, the US would manufacture all the bombs and allocate some to Britain.
Igor Kurchatov
In the wake of the successful detonation of the U.S's first fusion device, codenamed "Ivy Mike" in 1952, Stalin ordered Soviet scientists to build a comparable device, a program that was launched in 1953. The directors of this project were Vitaly Ginzburg and Andrei Sakharov who originated this project as "Sakharov's Third Idea". Kurchatov contributed some of the calculations necessary for the Soviet Union's first hydrogen bomb. Unlike Ginzburg, Sakharov, and Yakov Zel'dovich, Kurchatov was only involved in small scale calculations, applying the basic nuclear weapons principles used in the smaller nuclear weapons that were developed under his directorship. In 1953, the Soviet Union detonated its first thermonuclear device, codename "Joe 4". While other scientists, such as Ginzburg, Zel'dovich and Sakharov earned renown, Kurchatov's contribution was diminished.
Edward Teller
In 1942, Teller was invited to be part of Robert Oppenheimer's summer planning seminar, at the University of California, Berkeley for the origins of the Manhattan Project, the Allied effort to develop the first nuclear weapons. A few weeks earlier, Teller had been meeting with his friend and colleague Enrico Fermi about the prospects of atomic warfare, and Fermi had nonchalantly suggested that perhaps a weapon based on nuclear fission could be used to set off an even larger nuclear fusion reaction. Even though he initially explained to Fermi why he thought the idea would not work, Teller was fascinated by the possibility and was quickly bored with the idea of "just" an atomic bomb even though this was not yet anywhere near completion. At the Berkeley session, Teller diverted discussion from the fission weapon to the possibility of a fusion weapon—what he called the "Super", an early concept of what was later to be known as a hydrogen bomb.
Nuclear weapon design
With its original mission no longer available, the Livermore lab tried radical new designs that failed. Its first three nuclear tests were fizzles: in 1953, two single-stage fission devices with uranium hydride pits, and in 1954, a two-stage thermonuclear device in which the secondary heated up prematurely, too fast for radiation implosion to work properly.
Neutron
The neutron is essential to the production of nuclear power. In the decade after the neutron was discovered by James Chadwick in 1932, neutrons were used to induce many different types of nuclear transmutations. With the discovery of nuclear fission in 1938, it was quickly realized that, if a fission event produced neutrons, each of these neutrons might cause further fission events, etc., in a cascade known as a nuclear chain reaction. These events and findings led to the first self-sustaining nuclear reactor (Chicago Pile-1, 1942) and the first nuclear weapon (Trinity, 1945).
Bomb
A thermonuclear weapon is a type of nuclear bomb that releases energy through the combination of fission and fusion of the light atomic nuclei of deuterium and tritium. With this type of bomb, a thermonuclear detonation is triggered by the detonation of a fission type nuclear bomb contained within a material containing high concentrations of deuterium and tritium. Weapon yield is typically increased with a tamper that increases the duration and intensity of the reaction through inertial confinement and neutron reflection. Nuclear fusion bombs can have arbitrarily high yields making them hundreds or thousands of times more powerful than nuclear fission.
Thermonuclear weapon
In 1945, the French Atomic Energy Commission (Commissariat à l’Énergie Atomique, CEA) was founded under Charles de Gaulle; the CEA served as the country's atomic energy authority, overseeing commercial, military, and scientific uses of atomic power. However it was not until 1952 that a tangible goal of building plutonium reactors progressed. Two years later, a reactor was being built and a plutonium separating plant began construction shortly after. In 1954 the question about continuing to explore building an atomic bomb was raised. The French cabinet seemed to be favoring less the building of an atomic bomb. Ultimately, the Prime Minister decided to continue efforts developing an atomic bomb in secret. In late 1956, tasks were delegated between the CEA and Defense Ministry to propel atomic development such as finding a test site, providing the necessary uranium, and physical device assembly.
British hydrogen bomb programme
The scientists at the United Kingdom Atomic Energy Authority's Atomic Weapons Establishment at Aldermaston in Berkshire included William Penney, William Cook, Ken Allen, Samuel Curran, Henry Hulme, Bryan Taylor and John Ward. They did not know how to build a hydrogen bomb, but produced three designs: Orange Herald, a large boosted fission weapon; Green Bamboo, an interim thermonuclear design; and Green Granite, a true thermonuclear design. The first series of Operation Grapple tests involved Britain's first airdrop of a thermonuclear bomb. Although hailed as a success at the time, the first test of the Green Granite design was a failure. The second test validated Orange Herald as a usable design of a megaton weapon, but it was not a thermonuclear bomb, and the core boosting did not work. A third test attempted to correct the Green Granite design, but was another failure.
Nuclear warfare
With the monopoly over nuclear technology broken, worldwide nuclear proliferation accelerated. The United Kingdom tested its first independent atomic bomb in 1952, followed by France in 1960 and then China in 1964. While much smaller than the arsenals of the United States and the Soviet Union, Western Europe's nuclear reserves were nevertheless a significant factor in strategic planning during the Cold War. A top-secret White Paper, compiled by the Royal Air Force and produced for the British Government in 1959, estimated that British bombers carrying nuclear weapons were capable of destroying key cities and military targets in the Soviet Union, with an estimated 16 million deaths in the Soviet Union (half of whom were estimated to be killed on impact and the rest fatally injured) "before" bomber aircraft from the U.S. Strategic Air Command reached their targets.
Pre-emptive nuclear strike
In the immediate aftermath of World War II, the leadership of the Soviet Union feared the United States would use its nuclear superiority to its advantage, as from 1945 to 1948 the U.S. was the only state possessing nuclear weapons. The USSR countered by rapidly developing their own nuclear weapons, surprising the US with their first test in 1949. In turn, the U.S. countered by developing the vastly more powerful thermonuclear weapon, testing their first hydrogen bomb in 1952 at Ivy Mike, but the USSR quickly countered by testing their own thermonuclear weapons, with a test in 1953 of a semi-thermonuclear weapon of the Sloika design, and in 1956, with the testing of Sakharov's Third Idea – equivalent to the Castle Bravo device. Meanwhile, tensions between the two nations rose as 1956 saw the suppression of Hungary by the Soviets; the U.S. and European nations drew certain conclusions from that event, while in the U.S., a powerful social backlash was afoot, prompted by Senator Joseph McCarthy, the House Un-American Activities Committee, and Julius and Ethel Rosenberg, U.S. citizens executed in 1953 after conviction of espionage. This atmosphere was further inflamed by the 1957 launch of Sputnik, which led to fears of Communists attacking from outer space, as well as concerns that if the Soviets could launch a device into orbit, they could equally cause a device to re-enter the atmosphere and impact any part of the planet. John F. Kennedy capitalized on this situation by emphasizing the Bomber gap and the Missile gap, areas in which the Soviets were (inaccurately) perceived as leading the United States, while heated Soviet rhetoric added to political pressure. The 1960 U-2 incident, involving Francis Gary Powers, as well as the Berlin Crisis, along with the test of the Tsar Bomba, escalated tensions still further.
Nuclear weapons testing
The first atomic weapons test was conducted near Alamogordo, New Mexico, on July 16, 1945, during the Manhattan Project, and given the codename "Trinity". The test was originally to confirm that the implosion-type nuclear weapon design was feasible, and to give an idea of what the actual size and effects of a nuclear explosion would be before they were used in combat against Japan. While the test gave a good approximation of many of the explosion's effects, it did not give an appreciable understanding of nuclear fallout, which was not well understood by the project scientists until well after the atomic bombings of Hiroshima and Nagasaki.
History of nuclear weapons
In the end, President Truman made the final decision, looking for a proper response to the first Soviet atomic bomb test in 1949. On January 31, 1950, Truman announced a crash program to develop the hydrogen (fusion) bomb. At this point, however, the exact mechanism was still not known: the classical hydrogen bomb, whereby the "heat" of the fission bomb would be used to ignite the fusion material, seemed highly unworkable. However, an insight by Los Alamos mathematician Stanislaw Ulam showed that the fission bomb and the fusion fuel could be in separate parts of the bomb, and that "radiation" of the fission bomb could first work in a way to "compress" the fusion material before igniting it.
Nuclear weapons and the United Kingdom
An Operational Requirement (OR1142) was issued in 1955 for a thermonuclear warhead for a medium-range ballistic missile, which became Blue Streak. This was revised in November 1955, with "megaton" replacing "thermonuclear". Orange Herald could then meet the requirement. Codenamed Green Grass, the unsuccessful fusion boosting was omitted, and it used Green Bamboo's 72-lens implosion system instead of Orange Herald's 32. This allowed the amount of highly enriched uranium to be reduced from 120 to 75 kg. Its yield was estimated at . It was placed in a Blue Danube casing, and became known as Violet Club. Road transport of the weapon was hazardous. As a safety measure 120,000 steel ball bearings were used to fill a cavity inside the core and keep the fissile components apart. In an accident, the steel bung was removed and the ball bearings spilled on the floor of an aircraft hangar, leaving the bomb armed and dangerous. About ten were delivered.
The scientists at Aldermaston had not yet mastered the design of thermonuclear weapons. They produced a new design, called Round A. Another trial was scheduled, known as Grapple X. Round A was dropped on 8 November 1957. To save time and money, the target was off the southern tip of Christmas Island rather than off Malden Island, just from the airfield where 3,000 men were based. This time the yield of exceeded expectations. Round A was a true hydrogen bomb, but it used a relatively large quantity of expensive highly enriched uranium.
Thermonuclear weapon
Whether these statements vindicate some or all of the models presented above is up for interpretation, and official U.S. government releases about the technical details of nuclear weapons have been purposely equivocating in the past (see, e.g., Smyth Report). Other information, such as the types of fuel used in some of the early weapons, has been declassified, though precise technical information has not been.
Tube Alloys
The Tube Alloys programme in Britain and Canada was the first nuclear weapons project. Due to the high costs, and the fact that Britain was fighting a war within bombing range of its enemies, Tube Alloys was ultimately subsumed into the Manhattan Project by the Quebec Agreement with the United States, under which the two nations agreed to share nuclear weapons technology, and to refrain from using it against each other, or against other countries without mutual consent; but the United States did not provide complete details of the results of the Manhattan Project to the United Kingdom. The Soviet Union gained valuable information through its atomic spies, who had infiltrated both the British and American projects.
Thermonuclear weapon
A thermonuclear weapon, or fusion weapon, is a second-generation nuclear weapon design which affords vastly greater destructive power than first-generation atomic bombs. Modern fusion weapons consist essentially of two main components: a nuclear fission primary stage (fueled by Uranium-235 or Plutonium-239) and a separate nuclear fusion secondary stage containing thermonuclear fuel: the heavy hydrogen isotopes deuterium and tritium, or in modern weapons lithium deuteride. For this reason thermonuclear weapons are often colloquially called hydrogen bombs, or H-bombs.
List of states with nuclear weapons
The Soviet Union tested its first nuclear weapon ("RDS-1") in 1949. This crash project was developed partially with information obtained via espionage during and after World War II. The Soviet Union was the second nation to have developed and tested a nuclear weapon. The direct motivation for Soviet weapons development was to achieve a balance of power during the Cold War. It tested its first megaton-range hydrogen bomb ("RDS-37") in 1955. The Soviet Union also tested the most powerful explosive ever detonated by humans, ("Tsar Bomba"), with a theoretical yield of 100 megatons, intentionally reduced to 50 when detonated. After its dissolution in 1991, the Soviet weapons entered officially into the possession of the Russian Federation. The Soviet nuclear arsenal contained some 45,000 warheads at its peak (in 1986); the Soviet Union built about 55,000 nuclear warheads since 1949.
Thermonuclear weapon
The idea of a thermonuclear fusion bomb ignited by a smaller fission bomb was first proposed by Enrico Fermi to his colleague Edward Teller in 1941 at the start of what would become the Manhattan Project. Teller spent most of the Manhattan Project attempting to figure out how to make the design work, to some degree neglecting his assigned work on the fission bomb program. His difficult and devil's advocate attitude in discussions led Robert Oppenheimer to sidetrack him and other "problem" physicists into the super program to smooth his way.
Atomic Energy Act of 1946
Nuclear weapons were developed during World War II by the wartime Manhattan Project. Key scientists working on the project anticipated that their development would have wide-ranging implications. However the project director, Major General Leslie R. Groves Jr., was reluctant to spend project funds on activities beyond those required to win the war. Nonetheless, Arthur Compton of the Metallurgical Project in Chicago commissioned a report on post-war nuclear energy, and the Military Policy Committee, the Manhattan Project's governing body, commissioned a similar study by Richard Tolman. Both reports called for a comprehensive, government-supported nuclear energy program, with military, scientific, and industrial aspects.
History of nuclear weapons
It was thought at the time that a fission weapon would be quite simple to develop and that perhaps work on a hydrogen bomb (thermonuclear weapon) would be possible to complete before the end of the Second World War. However, in reality the problem of a regular atomic bomb was large enough to preoccupy the scientists for the next few years, much less the more speculative "Super" bomb. Only Teller continued working on the project—against the will of project leaders Oppenheimer and Hans Bethe.
History of nuclear weapons
Because of the difficulties in making a working plutonium bomb, it was decided that there should be a test of the weapon. On July 16, 1945, in the desert north of Alamogordo, New Mexico, the first nuclear test took place, code-named "Trinity", using a device nicknamed "the gadget." The test, a plutonium implosion-type device, released energy equivalent to 22 kilotons of TNT, far more powerful than any weapon ever used before. The news of the test's success was rushed to Truman at the Potsdam Conference, where Churchill was briefed and Soviet Premier Joseph Stalin was informed of the new weapon. On July 26, the Potsdam Declaration was issued containing an ultimatum for Japan: either surrender or suffer "complete and utter destruction", although nuclear weapons were not mentioned.
After hearing arguments from scientists and military officers over the possible use of nuclear weapons against Japan (though some recommended using them as demonstrations in unpopulated areas, most recommended using them against built up targets, a euphemistic term for populated cities), Truman ordered the use of the weapons on Japanese cities, hoping it would send a strong message that would end in the capitulation of the Japanese leadership, and avoid a lengthy invasion of the islands. Truman and his Secretary of State James F. Byrnes were also intent on ending the Pacific war before the Soviets could enter it, given that Roosevelt had promised Stalin control of Manchuria if he joined the invasion. On May 10–11, 1945, the Target Committee at Los Alamos, led by Oppenheimer, recommended Kyoto, Hiroshima, Yokohama, and Kokura as possible targets. Concerns about Kyoto's cultural heritage led to it being replaced by Nagasaki.
On August 6, 1945, a uranium-based weapon, Little Boy, was detonated above the Japanese city of Hiroshima, and three days later, a plutonium-based weapon, Fat Man, was detonated above the Japanese city of Nagasaki. To date, Hiroshima and Nagasaki remain the only two instances of nuclear weapons being used in combat. The atomic raids killed at least one hundred thousand Japanese civilians and military personnel outright, with the heat, radiation, and blast effects.
Many tens of thousands would later die of radiation sickness and related cancers. Truman promised a "rain of ruin" if Japan did not surrender immediately, threatening to systematically eliminate their ability to wage war. On August 15, Emperor Hirohito announced Japan's surrender.
Operation Greenhouse
Operation Greenhouse showcased new and aggressive designs for nuclear weapons. The main idea was to reduce the size, weight, and most importantly, reduce the amount of fissile material necessary for nuclear weapons, while increasing the destructive power. With the Soviet Union's first nuclear test a year and half earlier, the United States had begun stockpiling the new designs before they were actually proven. Thus the success of Operation Greenhouse was vital before the development of thermonuclear weapons could continue.
Thermonuclear weapon
The basic principle of the Teller–Ulam configuration is the idea that different parts of a thermonuclear weapon can be chained together in "stages", with the detonation of each stage providing the energy to ignite the next stage. At a bare minimum, this implies a "primary" section that consists of an implosion-type fission bomb (a "trigger"), and a "secondary" section that consists of fusion fuel. The energy released by the "primary" compresses the "secondary" through a process called "radiation implosion", at which point it is heated and undergoes nuclear fusion. This process could be continued, with energy from the secondary igniting a third fusion stage; Russia's AN602 "Tsar Bomba" is thought to have been a three-stage fission-fusion-fusion device. Theoretically by continuing this process thermonuclear weapons with arbitrarily high yield could be constructed. This contrasts with fission weapons which are limited in yield.
Redstone Arsenal
The People's Republic of China exploded its first thermonuclear bomb in June 1967. Hence, ABM system requirements were revised and the Sentinel System was born, replacing Nike-X. In 1968, the Army Ballistic Missile Defence Agency (ABMDA) was formed, taking over Sentinel and other ballistic missile defense projects previously under MICOM. Commanded by BG Drewry, ABMDA established operations adjacent to Redstone Arsenal in the Cummings Research Park. In May 1974, all ballistic missile defense efforts were consolidated under a single manager in the Ballistic Missile Defense Organization, which eventually evolved into today's U.S. Army Space and Missile Defense Command.
Thermonuclear weapon
The first Soviet fusion design, developed by Andrei Sakharov and Vitaly Ginzburg in 1949 (before the Soviets had a working fission bomb), was dubbed the "Sloika", after a Russian layer cake, and was not of the Teller–Ulam configuration. It used alternating layers of fissile material and lithium deuteride fusion fuel spiked with tritium (this was later dubbed Sakharov's "First Idea"). Though nuclear fusion might have been technically achievable, it did not have the scaling property of a "staged" weapon. Thus, such a design could not produce thermonuclear weapons whose explosive yields could be made arbitrarily large (unlike U.S. designs at that time). The fusion layer wrapped around the fission core could only moderately multiply the fission energy (modern Teller–Ulam designs can multiply it 30-fold). Additionally, the whole fusion stage had to be imploded by conventional explosives, along with the fission core, substantially multiplying the amount of chemical explosives needed.
Operation Grapple
The successful test of an atomic bomb in Operation Hurricane in October 1952 represented an extraordinary scientific and technological achievement. Britain became the world's third nuclear power, reaffirming the country's status as a great power, but hopes that the United States would be sufficiently impressed to restore the Special Relationship were soon dashed. In November 1952, the United States conducted Ivy Mike, the first successful test of a true thermonuclear device or hydrogen bomb. Britain was therefore still several years behind in nuclear weapons technology. The Defence Policy Committee, chaired by Churchill and consisting of the senior Cabinet members, considered the political and strategic implications in June 1954, and concluded that "we must maintain and strengthen our position as a world power so that Her Majesty's Government can exercise a powerful influence in the counsels of the world." In July 1954, Cabinet agreed to proceed with the development of thermonuclear weapons.
History of nuclear weapons
On March 1, 1954, the U.S. detonated its first practical thermonuclear weapon (which used isotopes of lithium as its fusion fuel), known as the "Shrimp" device of the Castle Bravo test, at Bikini Atoll, Marshall Islands. The device yielded 15 megatons, more than twice its expected yield, and became the worst radiological disaster in U.S. history. The combination of the unexpectedly large blast and poor weather conditions caused a cloud of radioactive nuclear fallout to contaminate over . 239 Marshall Island natives and 28 Americans were exposed to significant amounts of radiation, resulting in elevated levels of cancer and birth defects in the years to come.
Nuclear weapons and the United Kingdom
Churchill, now again prime minister, announced on 17 February 1952 that the first British weapon test would occur before the end of the year. During Operation Hurricane, an atomic bomb was detonated on board the frigate anchored in a lagoon in the Monte Bello Islands in Western Australia on 3 October 1952. Britain thereby became the third country to develop and test nuclear weapons.
This led to the development of the first deployed weapon, the Blue Danube free-fall bomb. It had a diameter, 32 explosive lens implosion system with a levitated pit suspended within a natural uranium tamper. The warhead was contained within a bomb casing measuring diameter and long, and it weighed approximately , of which about was high explosive. The first Blue Danube bombs were delivered to the Royal Air Force (RAF) Bomber Command in November 1953, although the bombers to deliver them did not become available until 1955.
Nuclear arms race
Both governments spent massive amounts to increase the quality and quantity of their nuclear arsenals. Both nations quickly began the development of a hydrogen bomb and the United States detonated the first hydrogen bomb on November 1, 1952, on Enewetak, an atoll in the Pacific Ocean. Code-named "Ivy Mike", the project was led by Edward Teller, a Hungarian-American nuclear physicist. It created a cloud 100 miles wide and 25 miles high, killing all life on the surrounding islands. Again, the Soviets surprised the world by exploding a deployable thermonuclear device in August 1953 although it was not a true multi-stage hydrogen bomb. However, it was small enough to be dropped from an airplane, making it ready for use. The development of these two Soviet bombs was greatly aided by the Russian spies Harry Gold and Klaus Fuchs.
Science and technology in China
China successfully tested a hydrogen bomb on June 17, 1967 at Lop Nur Nuclear Weapon Test Base, in Malan, Xinjiang (also known as "Test No. 6"). China became the fourth country to have successfully developed a thermonuclear weapon after the United States, Soviet Union and the United Kingdom. The device was dropped from a Hong-6 (Chinese manufactured Tu-16) and was parachute-retarded for an airburst at 2960 meters. The bomb was a three-stage device with a boosted U-235 primary and U-238 pusher. The yield was 3.3 megatons.
Richard Godwin
Graduated from Yale University with a bachelor's degree in Engineering in 1945. He moved to Washington, D.C. to become a reactor engineer for the United States Atomic Energy Commission. In 1953 he was sent to Livermore, California to develop and test the first thermonuclear weapons. In 1956, he was called back to Washington to work on the NS Savannah as Project Director.
Germany and weapons of mass destruction
During World War II, Germany conducted an unsuccessful project to develop nuclear weapons. German scientists also did research on other chemical weapons during the war, including human experimentation with mustard gas. The first nerve gas, tabun, was invented by the German researcher Gerhard Schrader in 1937.
Nuclear weapon design
The idea of the hydrogen bomb first came to public attention in 1949, when prominent scientists openly recommended against building nuclear bombs more powerful than the standard pure-fission model, on both moral and practical grounds. Their assumption was that critical mass considerations would limit the potential size of fission explosions, but that a fusion explosion could be as large as its supply of fuel, which has no critical mass limit. In 1949, the Soviets exploded their first fission bomb, and in 1950 U.S. President Harry S. Truman ended the H-bomb debate by ordering the Los Alamos designers to build one.
Nuclear weapon design
Pure fission weapons historically have been the first type to be built by new nuclear powers. Large industrial states with well-developed nuclear arsenals have two-stage thermonuclear weapons, which are the most compact, scalable, and cost effective option once the necessary technical base and industrial infrastructure are built.
Norris Bradbury
By 1951, the laboratory had come up with the Teller-Ulam design, and thermonuclear tests were conducted during Operation Greenhouse. Tensions between Bradbury and Edward Teller over the degree of priority given to thermonuclear weapons development led to the creation of a second nuclear weapons laboratory, the Lawrence Livermore Laboratory.
Tsar Bomba
The Soviet RDS-220 hydrogen bomb (code name "Ivan" or "Vanya"), known by Western nations as Tsar Bomba (), was the most powerful nuclear weapon ever created. Tested on 30 October 1961 as an experimental verification of calculation principles and multi-stage thermonuclear weapon designs, it also remains the most powerful explosive ever detonated. It was also referred to as "Kuzma's mother" (), possibly referring to First secretary Nikita Khrushchev's promise to "show the United States a Kuzma's mother" (an idiom roughly translating to "We'll show you") at a 1960 session of United Nations General Assembly.
History of nuclear weapons
As a show of political strength, the Soviet Union tested the largest-ever nuclear weapon in October 1961, the massive Tsar Bomba, which was tested in a reduced state with a yield of around 50 megatons—in its full state it was estimated to have been around 100 Mt. The weapon was largely impractical for actual military use, but was hot enough to induce third-degree burns at a distance of 62 mi (100 km) away. In its full, dirty, design it would have increased the amount of worldwide fallout since 1945 by 25%.
Nuclear fission
One class of nuclear weapon, a "fission bomb" (not to be confused with the "fusion bomb"), otherwise known as an "atomic bomb" or "atom bomb", is a fission reactor designed to liberate as much energy as possible as rapidly as possible, before the released energy causes the reactor to explode (and the chain reaction to stop). Development of nuclear weapons was the motivation behind early research into nuclear fission which the Manhattan Project during World War II (September 1, 1939 – September 2, 1945) carried out most of the early scientific work on fission chain reactions, culminating in the three events involving fission bombs that occurred during the war. The first fission bomb, codenamed "The Gadget", was detonated during the Trinity Test in the desert of New Mexico on July 16, 1945. Two other fission bombs, codenamed "Little Boy" and "Fat Man", were used in combat against the Japanese cities of Hiroshima and Nagasaki in on August 6 and 9, 1945 respectively.
Castle Romeo
This became the first air-droppable thermonuclear device, the EC-17, of which only 5 were made and the first deployable staged radiation implosion Teller-Ulam thermonuclear weapon. This evolved into the Mk 17 of which 200 were made. Both of these were huge devices, weighing 39,000 and 42,000 pounds respectively. As a result, they were only capable of being carried by the B-36. They were also some of the largest yield devices deployed by Strategic Air Command—the EC-17 giving around 10 Mt and the Mk17 between 11 and 15 Mt. They were all out of service by August 1957.
Castle Bravo
Castle Bravo was the first in a series of high-yield thermonuclear weapon design tests conducted by the United States at Bikini Atoll, Marshall Islands, as part of "Operation Castle". Detonated on March 1, 1954, the device was the most powerful nuclear device detonated by the United States and its first lithium deuteride fueled thermonuclear weapon. Castle Bravo's yield was 15 megatons of TNT, 2.5 times the predicted 6.0 megatons, due to unforeseen additional reactions involving Li, which led to the unexpected radioactive contamination of areas to the east of Bikini Atoll.
Vyacheslav Feodoritov
He took part in the testing of nuclear weapons and was the scientific lead in a number of tests. Along with his project lead, Yevgeny Zababakhin, and in addition to his work on the RDS-37, he worked on calculations for the core part of the RDS-6s bomb, the first Soviet thermonuclear weapon, and also worked on a design which became the first Soviet serial tactical nuclear weapon, RDS-4. Both devices were successfully completed in 1953. For this work he received the Stalin Prize, third degree and the Medal "For Labour Valour". He also worked on civilian nuclear projects. For further significant theoretical work and following successful weapons testing in 1954 and 1955, leading to a new generation of Soviet nuclear weaponry, he was awarded the Order of the Red Banner of Labour. In 1956, he originated further design improvements which helped lead to a new direction in Soviet nuclear weapons. He was part of the team which developed the RDS-220 thermonuclear weapon, the largest ever tested. With German Goncharov, he worked on the construction scheme of these types of weapons, and with Sakharov he analysed the efficiency of the theoretical model of the RDS-220. He received his PhD in Physical and Mathematical Sciences in 1968. For his role in the projects to develop nuclear weapons he was awarded the State Prize of the USSR in 1973. Later in his career, Feodoritov was one of the compilers of the "Atomic Project of the USSR", specifically "Documents and materials. Volume II. Atomic bomb. 1945 - 1954 Book 1" (published in 1999). He was honoured for his contributions as a scientist in 2000.
British hydrogen bomb programme
The successful test of an atomic bomb represented an extraordinary scientific and technological achievement. Britain became the world's third nuclear power, reaffirming its status as a great power, but hopes that the United States would be sufficiently impressed to restore the Special Relationship were soon dashed. On 1 November 1952, the United States conducted Ivy Mike, the first successful test of a true thermonuclear device (also known as a hydrogen bomb). Due to its physical size and use of cryogenic liquid deuterium, it was not suitable for use as a deliverable weapon, but the Castle Bravo test on 1 March 1954 used a much smaller device with solid lithium deuteride. Boosted by the nuclear fusion reaction in lithium-7, the yield of was more than twice what had been expected, and indeed was the largest detonation the Americans would ever carry out. This resulted in widespread radioactive fallout that affected 28 Americans, 236 Marshall Islanders, and the 23 crewmen of a Japanese fishing boat, the "Daigo Fukuryū Maru" ("Lucky Dragon No. 5"). Meanwhile, the Soviet Union tested Joe 4, a boosted fission weapon with a yield of on 12 August 1953. This was followed by Joe 19, a true two-stage thermonuclear weapon on 20 November 1954.
Thermonuclear weapon
On May 11, 1998, India reportedly detonated a thermonuclear bomb in its Operation Shakti tests ("Shakti-I", specifically). Dr. Samar Mubarakmand, a Pakistani nuclear physicist, asserted that Shakti-1 was a successful thermonuclear test. The yield of India's hydrogen bomb remains highly debatable among the Indian science community and the international scholars. The question of politicisation and disputes between Indian scientists further complicated the matter.
Thermonuclear weapon
According to the scientific data received and published by PAEC, the Corps of Engineers, and Kahuta Research Laboratories (KRL), in May 1998, Pakistan carried out six underground nuclear tests in Chagai Hills and Kharan Desert in Balochistan Province (see the code-names of the tests, "Chagai-I" and "Chagai-II"). None of these boosted fission devices was the thermonuclear weapon design, according to KRL and PAEC.
Nuclear weapon design
On July 19, 1956, AEC Chairman Lewis Strauss said that the Redwing Zuni shot clean bomb test "produced much of importance ... from a humanitarian aspect." However, less than two days after this announcement, the dirty version of Bassoon, called Bassoon Prime, with a uranium-238 tamper in place, was tested on a barge off the coast of Bikini Atoll as the Redwing Tewa shot. The Bassoon Prime produced a 5-megaton yield, of which 87% came from fission. Data obtained from this test, and others, culminated in the eventual deployment of the highest yielding US nuclear weapon known, and the highest yield-to-weight weapon ever made, a three-stage thermonuclear weapon with a maximum "dirty" yield of 25 megatons, designated as the B41 nuclear bomb, which was to be carried by U.S. Air Force bombers until it was decommissioned; this weapon was never fully tested.
W38
The W38 was the first thermonuclear ICBM warhead developed by the UCRL (University of California Radiation Laboratory), which is now known as the Lawrence Livermore National Laboratory.
History of nuclear weapons
Chinese nuclear warheads were produced from 1968 and thermonuclear warheads from 1974. It is also thought that Chinese warheads have been successfully miniaturised from 2200 kg to 700 kg through the use of designs obtained by espionage from the United States. The current number of warheads is unknown, but as of 2017 it is thought to be in the low hundreds. China is the only nuclear weapons state to have guaranteed the non-first use of nuclear weapons.
Thermonuclear weapon
Two years before his death in 1989, Andrei Sakharov's comments at a scientists’ forum helped begin the process for the elimination of thousands of nuclear ballistic missiles from the US and Soviet arsenals. Sakharov (1921–89) was recruited into the Soviet Union's nuclear weapons program in 1948, a year after he completed his doctorate. In 1949 the US detected the first Soviet test of a fission bomb, and the two countries embarked on a desperate race to design a thermonuclear hydrogen bomb that was a thousand times more powerful. Like his US counterparts, Sakharov justified his H-bomb work by pointing to the danger of the other country's achieving a monopoly. But also like some of the US scientists who had worked on the Manhattan Project, he felt a responsibility to inform his nation's leadership and then the world about the dangers from nuclear weapons. Sakharov's first attempt to influence policy was brought about by his concern about possible genetic damage from long-lived radioactive carbon-14 created in the atmosphere from nitrogen-14 by the enormous fluxes of neutrons released in H-bomb tests. In 1968 a friend suggested that Sakharov write an essay about the role of the intelligentsia in world affairs. Self-publishing was the method at the time for spreading unapproved manuscripts in the Soviet Union. Many readers would create multiple copies by typing with multiple sheets of paper interleaved with carbon paper. One copy of Sakharov's essay, "Reflections on Progress, Peaceful Coexistence, and Intellectual Freedom," was smuggled out of the Soviet Union and published by the New York Times. More than 18 million reprints were produced during 1968–69. After the essay was published, Sakharov was barred from returning to work in the nuclear weapons program and took a research position in Moscow. In 1980, after an interview with the New York Times in which he denounced the Soviet invasion of Afghanistan the government put him beyond the reach of Western media by exiling him and his wife to Gorky. In March 1985 Gorbachev became general secretary of the Soviet Communist Party. More than a year and a half later, he persuaded the Politburo, the party's executive committee, to allow Sakharov and Bonner to return to Moscow. Sakharov was elected as an opposition member to the Soviet Congress of People's Deputies in 1989. Later that year he had a cardiac arrhythmia and died in his apartment. He left behind a draft of a new Soviet constitution that emphasized democracy and human rights.
Nuclear weapon design
In the ensuing fifty years, nobody has come up with a more efficient way to build a nuclear bomb. It is the design of choice for the United States, Russia, the United Kingdom, China, and France, the five thermonuclear powers. On 3 September 2017 North Korea carried out what it reported as its first "two-stage thermo-nuclear weapon" test. According to Dr. Theodore Taylor, after reviewing leaked photographs of disassembled weapons components taken before 1986, Israel possessed boosted weapons and would require supercomputers of that era to advance further toward full two-stage weapons in the megaton range without nuclear test detonations. The other nuclear-armed nations, India and Pakistan, probably have single-stage weapons, possibly boosted.
Nuclear warfare
On August 29, 1949, the Soviet Union tested its first nuclear weapon at Semipalatinsk in Kazakhstan (see also Soviet atomic bomb project). Scientists in the United States from the Manhattan Project had warned that, in time, the Soviet Union would certainly develop nuclear capabilities of its own. Nevertheless, the effect upon military thinking and planning in the United States was dramatic, primarily because American military strategists had not anticipated the Soviets would "catch up" so soon. However, at this time, they had not discovered that the Soviets had conducted significant nuclear espionage of the project from spies at Los Alamos, the most significant of which was done by the theoretical physicist Klaus Fuchs. The first Soviet bomb was more or less a deliberate copy of the Fat Man plutonium device. In the same year the first US-Soviet nuclear war plan was penned in the US with Operation Dropshot.
Edward Teller
Carey Sublette of Nuclear Weapon Archive argues that Ulam came up with the radiation implosion compression design of thermonuclear weapons, but that on the other hand Teller has gotten little credit for being the first to propose fusion boosting in 1945, which is essential for miniaturization and reliability and is used in all of today's nuclear weapons.
Nuclear technology
Nuclear fusion was initially pursued only in theoretical stages during World War II, when scientists on the Manhattan Project (led by Edward Teller) investigated it as a method to build a bomb. The project abandoned fusion after concluding that it would require a fission reaction to detonate. It took until 1952 for the first full hydrogen bomb to be detonated, so-called because it used reactions between deuterium and tritium. Fusion reactions are much more energetic per unit mass of fuel than fission reactions, but starting the fusion chain reaction is much more difficult.
J. Carson Mark
Mark played a key role in the development of thermonuclear weapons in the early 1950s. A crash program to develop the hydrogen bomb was approved by President Harry S. Truman in January 1950 at Edward Teller's urging before the laboratory had a workable design. This put the laboratory under great pressure. Hans Bethe recalled that "There was a lot of controversy in Los Alamos in those days, and Carson always was imperturbable and stood in the middle of it and had a balanced judgment." When Stanislaw Ulam finally came up with a workable design, it was Mark that he approached first. Mark took the Ulam design to Bradbury, and they put the idea to Teller. "Teller then completed and extended the invention," Bethe noted, "so, in this case, Carson was the mediator between two people who really didn't like each other." "Within an hour of Carson's ... remarks," Teller recalled, "I knew how to move ahead". The Teller-Ulam design would become that of all thermonuclear weapons.
When it came to testing the design in the Ivy Mike nuclear test, Mark again had a crucial go-between role. Bradbury placed Marshall Holloway in charge, but Holloway and Teller did not get along. Mark later recalled that:
The Ivy Mike test was successful, obliterating an island in Enewetak Atoll in the Pacific on November 1, 1952.
History of the Teller–Ulam design
The People's Republic of China detonated its first device using a Teller–Ulam design June 1967 ("Test No. 6"), a mere 32 months after detonating its first fission weapon (the shortest fission-to-fusion development yet known), with a yield of 3.3 Mt. Little is known about the Chinese thermonuclear program, however.
Thermonuclear weapon
Efforts in the United States soon shifted towards developing miniaturized Teller–Ulam weapons that could fit into intercontinental ballistic missiles and submarine-launched ballistic missiles. By 1960, with the W47 warhead deployed on Polaris ballistic missile submarines, megaton-class warheads were as small as 18 inches (0.5 m) in diameter and 720 pounds (320 kg) in weight. It was later found in live testing that the Polaris warhead did not work reliably and had to be redesigned. Further innovation in miniaturizing warheads was accomplished by the mid-1970s, when versions of the Teller–Ulam design were created that could fit ten or more warheads on the end of a small MIRVed missile (see the section on the W88 below).
Meson bomb
Mesons (hadronic subatomic particles composed of one quark and one antiquark, bound together by the strong interaction) were proposed to form a nuclear weapon as early as the 1940s. Early speculation suggested that the resulting bomb would be the most powerful nuclear weapon yet to have been developed. American physicist Ernest Lawrence used the potential military applications of mesons to obtain funding for its synchrocyclotron built between 1940 and 1946 at the University of California, Berkeley. Soon, however, the scientific consensus was that construction of such a bomb would be impossible; and in 1968 physicist M. Stanley Livingston wrote that "no responsible scientists would attempt to justify support in this field with predictions of an 'anti-matter engine,' or a super 'meson bomb,' or a 'hyper-drive' for spaceships."
List of states with nuclear weapons
France tested its first nuclear weapon in 1960 ("Gerboise Bleue"), based mostly on its own research. It was motivated by the Suez Crisis diplomatic tension "vis-à-vis" both the Soviet Union and the Free World allies United States and United Kingdom. It was also relevant to retain great power status, alongside the United Kingdom, during the post-colonial Cold War (see: Force de frappe). France tested its first hydrogen bomb in 1968 ("Opération Canopus"). After the Cold War, France has disarmed 175 warheads with the reduction and modernization of its arsenal that has now evolved to a dual system based on submarine-launched ballistic missiles (SLBMs) and medium-range air-to-surface missiles (Rafale fighter-bombers). However new nuclear weapons are in development and reformed nuclear squadrons were trained during Enduring Freedom operations in Afghanistan. France signed the Nuclear Non-Proliferation Treaty in 1992. In January 2006, President Jacques Chirac stated a terrorist act or the use of weapons of mass destruction against France would result in a nuclear counterattack. In February 2015, President Francois Hollande stressed the need for a nuclear deterrent in "a dangerous world". He also detailed the French deterrent as "less than 300" nuclear warheads, three sets of 16 submarine-launched ballistic missiles and 54 medium-range air-to-surface missiles" and urged other states to show similar transparency.
Early thermal weapons
Early thermal weapons were devices or substances used in warfare during the classical and medieval periods (approx 8th century BC until the mid-16th century AD) which used heat or burning action to destroy or damage enemy personnel, fortifications or territories.
Project Y
The discovery of the neutron by James Chadwick in 1932, followed by that of nuclear fission by German chemists Otto Hahn and Fritz Strassmann in 1938, and its theoretical explanation (and naming) by Lise Meitner and Otto Frisch soon after, opened up the possibility of a controlled nuclear chain reaction using uranium. At the time, few scientists in the United States thought that an atomic bomb was practical, but the possibility that a German atomic bomb project would develop atomic weapons sufficiently concerned scientists who were refugees from Nazi Germany and other fascist countries, that they drafted the Einstein–Szilard letter to warn President Franklin D. Roosevelt. This prompted preliminary research in the United States, beginning in late 1939.
Progress was slow in the United States, but in Britain, Otto Frisch and Rudolf Peierls, two refugee physicists from Germany at the University of Birmingham, examined the theoretical issues involved in developing, producing and using atomic bombs. They considered what would happen to a sphere of pure uranium-235, and found that not only could a chain reaction occur, but it might require as little as of uranium-235 to unleash the energy of hundreds of tons of TNT. Their superior, Mark Oliphant, took the Frisch–Peierls memorandum to Sir Henry Tizard, the chairman of the Committee for the Scientific Survey of Air Warfare (CSSAW), who in turn passed it on to George Paget Thomson, to whom the CSSAW had delegated responsibility for uranium research. CSSAW created the MAUD Committee to investigate. In its final report in July 1941, the MAUD Committee concluded that an atomic bomb was not only feasible, but might be produced as early as 1943. In response, the British government created a nuclear weapons project known as Tube Alloys.
Operation Greenhouse
Operation Greenhouse was the fifth American nuclear test series, the second conducted in 1951 and the first to test principles that would lead to developing thermonuclear weapons ("hydrogen bombs"). Conducted at the new Pacific Proving Ground, specifically on islands of the Enewetak Atoll, all of the devices were mounted in large steel towers, to simulate air bursts. This series of nuclear weapons tests was preceded by Operation Ranger and succeeded by Operation Buster-Jangle.
Nuclear weapon
Only six countries—United States, Russia, 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 a fusion weapon , 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 is more efficient.
Mark 16 nuclear bomb
The Mark 16 nuclear bomb was a large thermonuclear bomb (hydrogen bomb), based on the design of the Ivy Mike, the first thermonuclear device ever test fired. The Mark 16 is more properly designated TX-16/EC-16 as it only existed in Experimental/Emergency Capability (EC) versions.
Manhattan Project
The Manhattan Project was a research and development undertaking during World War II that produced the first nuclear weapons. It was led by the United States with the support of the United Kingdom and Canada. From 1942 to 1946, the project was under the direction of Major General Leslie Groves of the U.S. Army Corps of Engineers. Nuclear physicist Robert Oppenheimer was the director of the Los Alamos Laboratory that designed the actual bombs. The Army component of the project was designated the Manhattan District; "Manhattan" gradually superseded the official codename, Development of Substitute Materials, for the entire project. Along the way, the project absorbed its earlier British counterpart, Tube Alloys. The Manhattan Project began modestly in 1939, but grew to employ more than 130,000 people and cost nearly US$2 billion (about $ in dollars). Over 90% of the cost was for building factories and to produce fissile material, with less than 10% for development and production of the weapons. Research and production took place at more than 30 sites across the United States, the United Kingdom, and Canada.
Mark 13 nuclear bomb
As the Mark 13 neared production, advances in thermonuclear weapon design, particularly the Ivy Mike thermonuclear test in November 1952, made the Mark 13 obsolete. Development continued for research purposes (the Upshot-Knothole Harry test shot came months after the first thermonuclear test in Ivy Mike), and in two variant designs, but the Mark 13 proper was never deployed. The Mark 13 bomb version was cancelled in August 1953, and the W-13 warhead version was cancelled in September 1953.
HGM-25A Titan I
The program began in January 1955 when the Scientific Advisory Committee recommended an alternate approach to the ICBM. This recommendation was built upon parallel work of another committee the Teapot Committee, that studied and validated a breakthrough in nuclear weapons' design; which promised the ability to build the most powerful (thermonuclear) weapons, at flight weights (and overall sizes) that were smaller and lighter than the fission bombs that were then presently available The committees’ presented to the Air Force their findings of the technical feasibility to develop weapons (bombs) and their delivery systems (intercontinental range ballistic missiles) that were completely invulnerable to "surprise" attack. And; for the then foreseeable future, to be invulnerable to defeat by intercept; before such missiles’ nuclear warheads, had destroyed the targets they had been aimed at. The ultimate deterrent weapons.
Nuclear weapon design
ERWs were two-stage thermonuclears with all non-essential uranium removed to minimize fission yield. Fusion provided the neutrons. Developed in the 1950s, they were first deployed in the 1970s, by U.S. forces in Europe. The last ones were retired in the 1990s.
Thermonuclear weapon
Most of the current ideas on the workings of the Teller–Ulam design came into public awareness after the Department of Energy (DOE) attempted to censor a magazine article by U.S. antiweapons activist Howard Morland in 1979 on the "secret of the hydrogen bomb". In 1978, Morland had decided that discovering and exposing this "last remaining secret" would focus attention onto the arms race and allow citizens to feel empowered to question official statements on the importance of nuclear weapons and nuclear secrecy. Most of Morland's ideas about how the weapon worked were compiled from highly accessible sources—the drawings that most inspired his approach came from none other than the "Encyclopedia Americana". Morland also interviewed (often informally) many former Los Alamos scientists (including Teller and Ulam, though neither gave him any useful information), and used a variety of interpersonal strategies to encourage informative responses from them (i.e., asking questions such as "Do they still use spark plugs?" even if he was not aware what the latter term specifically referred to).
Nuclear proliferation
Research into the development of nuclear weapons was initially undertaken during World War II by the United States (in cooperation with the United Kingdom and Canada), Germany, Japan, and the USSR. The United States was the first and is the only country to have used a nuclear weapon in war, when it used two bombs against Japan in August 1945. After surrendering to end the war, Germany and Japan ceased to be involved in any nuclear weapon research. In August 1949, the USSR tested a nuclear weapon, becoming the second country to detonate a nuclear bomb. The United Kingdom first tested a nuclear weapon in October 1952. France first tested a nuclear weapon in 1960. The People's Republic of China detonated a nuclear weapon in 1964. India conducted its first nuclear test in 1974, which prompted Pakistan to develop its own nuclear program and, when India conducted a second series of nuclear tests in 1998, Pakistan followed with a series of tests of its own. In 2006, North Korea conducted its first nuclear test.
Nuclear weapon design
The first effort to exploit the symbiotic relationship between fission and fusion was a 1940s design that mixed fission and fusion fuel in alternating thin layers. As a single-stage device, it would have been a cumbersome application of boosted fission. It first became practical when incorporated into the secondary of a two-stage thermonuclear weapon.
Thermonuclear weapon
The Soviets demonstrated the power of the "staging" concept in October 1961, when they detonated the massive and unwieldy "Tsar Bomba", a 50 megaton hydrogen bomb that derived almost 97% of its energy from fusion. It was the largest nuclear weapon developed and tested by any country.
Nuclear weapon design
It was first tested standalone and then as the primary of a two-stage thermonuclear device during Operation Redwing. It was weaponized as the Robin primary and became the first off-the-shelf, multi-use primary, and the prototype for all that followed.
National technical means of verification
France tested its first nuclear weapon on February 13, 1960 in Algeria. This came as no surprise, as multiple US intelligence sources and methods had been following the program since France began considering nuclear weapons in 1946.
Nuclear weapons and Israel
The first extensive details of the weapons program came in the London-based "Sunday Times" on October 5, 1986, which printed information provided by Mordechai Vanunu, a technician formerly employed at the Negev Nuclear Research Center near Dimona. For publication of state secrets Vanunu was kidnapped by the Mossad in Rome, brought back to Israel, and sentenced to 18 years in prison for treason and espionage. Although there had been much speculation prior to Vanunu's revelations that the Dimona site was creating nuclear weapons, Vanunu's information indicated that Israel had also built thermonuclear weapons.
Nuclear weapon
Thermonuclear bombs work by using 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 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 the yield comes from the final fissioning of depleted uranium.
Joe 4
Joe 4 (warhead name: RDS-6s ("Reaktivnyi Dvigatel Specialnyi"; Special Jet Engine)) was an American nickname for the first Soviet test of a thermonuclear weapon on August 12, 1953, that detonated with a force equivalent to 400 kilotons of TNT.
William Penney, Baron Penney
In the mid 1950s Britain felt the need to quickly develop megaton class weapons because it seemed that atmospheric testing could soon be outlawed by treaty. As a result, the UK wanted to demonstrate its ability to manufacture megaton class weapons by proof-testing them before any legal prohibitions were in place. According to an article in "New Scientist", Prime Minister Harold Macmillan was also hoping to convince the US to change the McMahon Act, which prohibited sharing information even with the British, by demonstrating that the UK had the technology to make a thermonuclear weapon (an H-bomb), and he put Penney in charge of developing this bomb. The Orange Herald bomb was developed and was passed off as a thermonuclear bomb, when in fact it was a boosted fission weapon in which little of the energy came from fusion. The test of this weapon was successful in convincing the Americans to allow information sharing with the British.
Thermonuclear weapon
France's journey in building nuclear weapons began prior to World War II in 1939. The development of nuclear weapons was slowed during the country's German invasion. The United States did not want France to acquire expert knowledge about nuclear weaponry, which ultimately led to the Alsos Mission. The missions followed closely behind the advancing forward-front to obtain information about how close Germany was to building an atomic weapon. Following the surrender of the Nazis, Germany was divided into "zones of occupation". The "zone" given to the French was suspected to contain several nuclear research facilities. The United States conducted Operation Harborage to seize any and all information about nuclear weaponry from the French. The Operation strategized to have American troops intercede advancing French army, allowing the Americans to seize any German scientists or records as well as destroy the remaining functional facilities.
History of nuclear weapons
The notion of using a fission weapon to ignite a process of nuclear fusion can be dated back to 1942. At the first major theoretical conference on the development of an atomic bomb hosted by J. Robert Oppenheimer at the University of California, Berkeley, participant Edward Teller directed the majority of the discussion towards Enrico Fermi's idea of a "Super" bomb that would use the same reactions that powered the Sun itself.
1958 US–UK Mutual Defence Agreement
The first British atomic bomb was successfully tested in Operation Hurricane on 3 October 1952, 
but although it was more advanced than the American bombs of 1946, Britain was still several years behind in nuclear weapons technology. The United States conducted Ivy Mike, the first nuclear test of a true thermonuclear device (also known as a hydrogen bomb). The JCAE saw little benefit for the United States from sharing technology with Britain. The Soviet Union responded with the test of Joe 4, a boosted fission weapon on 12 August 1953. This prompted President Dwight Eisenhower, who was inaugurated in January 1953, to inform the United States Congress that the McMahon Act, which he considered a "terrible piece of legislation" and "one of the most deplorable incidents in American history of which he personally felt ashamed", was obsolete.
At the three-power Bermuda Conference in December 1953, Eisenhower and Churchill discussed the possibility of the United States giving Britain access to American nuclear weapons in wartime. This came to be called Project E. There were technical and legal issues that had to be overcome before American bombs could be carried in British aircraft. The United States would have to disclose their weights and dimensions, while their delivery would require data concerning their ballistics. Further down the track, there would also be issues of custody, security and targeting. The release of such information was restricted by the McMahon Act.
Thermonuclear weapon
Two special variations exist that will be discussed in a subsequent section: the cryogenically cooled liquid deuterium device used for the Ivy Mike test, and the putative design of the W88 nuclear warhead—a small, MIRVed version of the Teller–Ulam configuration with a prolate (egg or watermelon shaped) primary and an elliptical secondary.
Nuclear weapon
Even before the first nuclear weapons had been developed, scientists involved with the Manhattan Project were divided over the use of the weapon. The role of the two atomic bombings of the country in Japan's surrender and the U.S.'s ethical justification for them has been the subject of scholarly and popular debate for decades. The question of whether nations should have nuclear weapons, or test them, has been continually and nearly universally controversial.Over 500 atmospheric nuclear weapons tests were conducted at various sites around the world from 1945 to 1980. Radioactive fallout from nuclear weapons testing was first drawn to public attention in 1954 when the Castle Bravo hydrogen bomb test at the Pacific Proving Grounds contaminated the crew and catch of the Japanese fishing boat "Lucky Dragon". One of the fishermen died in Japan seven months later, and the fear of contaminated tuna led to a temporary boycotting of the popular staple in Japan. The incident caused widespread concern around the world, especially regarding the effects of nuclear fallout and atmospheric nuclear testing, and "provided a decisive impetus for the emergence of the anti-nuclear weapons movement in many countries".
Yuri Romanov (physicist)
On 10 June 1948, Tamm headed a new group of theorists which included Andrei Sakharov, Vitaly Ginzburg, S.Z. Belenky and Romanov. They followed up Sakharov's ideas for a new thermonuclear weapon and went to KB-11 (now the All-Russian Scientific Research Institute of Experimental Physics) in the closed city of Sarov, Nizhny Novgorod. He started as a junior researcher, then senior, then head of department. In 1952, he received a degree in Physical and Mathematical Sciences with a thesis on kinetic processes of neutrons. This work on neutrons and efficiency continued, along with calculations on nuclear reaction kinetics and energy release of the Soviet Union's first thermonuclear weapon, the RDS-6, tested in 1953; for this he was awarded the Stalin Prize, the first of several awards. He was a leading developer of the RDS-37 - the first Soviet two-stage thermonuclear weapon - most specifically concerned with the power output. Romanov transferred to the new Scientific Research Institute-1011 as head of the theoretical department in 1955. Two years later, his team had developed a new megatonne-yield bomb design. He gained a Ph.D. in Physical and Mathematical Sciences in 1958 and was appointed to professorship of theoretical physics in 1962.
Oliver Haywood
Haywood was seconded to the Los Alamos National Laboratory in New Mexico from February 1950 to October 1951, at a time when the first thermonuclear weapons were being developed. Edward Teller once remarked that "Colonel Haywood is the only military man I would work for." Haywood then served at the chief of the Air Force Office of Scientific Research, and was vice commander of the Atlantic Missile Range until his retirement from active duty in 1953. He remained with the Air Force Reserve, retiring with the rank of brigadier general in 1967.
Pre-emptive nuclear strike
During the Cold War period, both superpowers, NATO and the Eastern Bloc, built massive nuclear arsenals, aimed, to a large extent, at each other. However, they were never used, as after a time, leaders on both sides of the Iron Curtain realized that global thermonuclear war would not be in either power's interest, as it would probably lead to the destruction of both sides, and possibly nuclear winter or other extinction level events. Therefore, at times, both sides refrained from deploying systems capable of unanswerable nuclear strikes against either side. However, in both blocs, there were interests that benefited from the development and maintenance of first-strike weapons systems: what U.S. President Dwight Eisenhower termed the military-industrial complex; these forces encouraged the constant development of weapons systems of greater accuracy, power, and destruction. In addition, each side doubted the other side's commitment to not deploy first-strike weapons, or even in the event of their deployment, to not strike first. Some first-strike weapons were deployed; however like most nuclear weapons, they were never used.
RDS-37
It was air-dropped at Semipalatinsk Test Site, Kazakhstan, making it the first air-dropped two-stage thermonuclear test. It would become the largest explosion realized at the Semipaltinsk test site. The "RDS-6s" device (Joe-4) exploded in 1953 had one-stage design, and was not scalable into the megaton yield range. The RDS-37 was dropped from a Tupolev Tu-16 bomber and was used most through the late 1950s and 1960s. After a while the Soviet Union felt as if the 2.9-megaton thermonuclear bomb was excessive for some missions, so the less powerful RP-30 and RP-32 200-kiloton bombs were ready for some missions. It would take the United States until 20 May 1956, about half a year, to achieve the same results through the Cherokee nuclear weapons test.
Thermonuclear weapon
The Soviet thermonuclear weapons program was aided heavily by Klaus Fuchs. Fuchs’ most valuable contribution to the Soviet weapons program concerned the hydrogen bomb. The idea of a hydrogen bomb arose from discussions between Enrico Fermi and Edward Teller in 1941. From 1943 Teller lectured at Los Alamos on what he called the "super". Following their meeting, Fermi was convinced by Teller to present a series of lectures detailing the current state of research into thermonuclear weapons. In September 1945 Fuchs passed a synopsis of these lectures to the Soviets. This information was important to the Soviets, but not solely for the information about the US bomb project. The importance of this material was in that it confirmed that the United States were working on their own thermonuclear weapon research. Although the information provided by Fuchs regarding the thermonuclear weapons research was not seen as entirely beneficial, it still provided the Soviet Union with knowledge such as the properties of tritium. Tritium is an isotope of hydrogen with two neutrons, which allows for more efficient fusion reactions to occur during the detonation of a nuclear weapon. Discovering the properties of this radioactive material would allow the Soviet Union to develop a more powerful weapon that requires less fuel. Following Fuchs's return, experts from the Soviet Union spent a great deal of time researching his findings for themselves. Even though the Soviets did obtain some original ideas, the findings of this research served to confirm Fuchs's notes from the American lectures on the matter. After his return to England in mid-1946, Fuchs was not again in touch with Soviet intelligence until September 1947, when his controller confirmed the Soviet interest in thermonuclear weapons. In response Fuchs provided details of the "ongoing theoretical superbomb studies in the U.S. under the direction of Teller and Enrico Fermi at the University of Chicago." Fuchs obtained information regardless of the American McMahon Act, which prevented Anglo-American cooperation on nuclear weapons research. Under this act, Fuchs did not have routine access to American collaborators like Fermi and Teller. Fuchs was very close to Teller at Los Alamos, and while there Fuchs had worked on thermonuclear weapons. As Teller later recalled, "he [Fuchs] talked with me and others frequently in depth about our intensive efforts… it was easy and pleasant to discuss my work with him. He also made impressive contributions, and I learned many technical facts from him." Fuchs obtained the information, it energized the Soviets to direct new intelligence activities against research in Chicago. In February 1948 the Soviet Union formally began its hydrogen bomb program. A month later Fuchs again met with Feklisov, an event which "played an exceptional role in the subsequent course of the Soviet thermonuclear bomb program." A report of June 1953 warned that, although no indication of Soviet development of hydrogen bombs had been found, "Soviet research, development and even field testing of thermonuclear reactions based on the disclosures of Fuchs may take place by mid-1953." U.S. intelligence thus recognized for the first time that Fuchs' material held invaluable information for the Soviet thermonuclear weapons program.
Gerboise Bleue
In 1968, France detonated its first thermonuclear weapon, Canopus (2.6Mt), at the new facility at Fangataufa, a desert atoll in French Polynesia."Gerboise Rouge" was followed by a joint exercise, in which infantry, helicopters and armour reconnoitered the contaminated area.
Ivy Mike
Ivy Mike was the codename given to the first test of a full-scale thermonuclear device, in which part of the explosive yield comes from nuclear fusion. It was detonated on November 1, 1952 by the United States on the island of Elugelab in Enewetak Atoll, in the Pacific Ocean, as part of Operation Ivy. It was the first full test of the Teller–Ulam design, a staged fusion device.
Red Beard (nuclear weapon)
Red Beard was the first British tactical nuclear weapon. It was carried by the English Electric Canberra and the V bombers of the Royal Air Force (RAF), and by the Blackburn Buccaneers, Sea Vixens, and Supermarine Scimitars of the Royal Navy's (RN) Fleet Air Arm (FAA). Developed to Operational Requirement 1127 (OR.1127), it was introduced in 1961, entered service in 1962. It was replaced by the WE.177 in the early 1970s and was withdrawn in 1971.
Fusion power
The first experiment to achieve controlled thermonuclear fusion was accomplished using Scylla I at the Los Alamos National Laboratory in 1958. Scylla I was a θ-pinch machine, with a cylinder full of deuterium. Electric current shot down the sides of the cylinder. The current made magnetic fields that pinched the plasma, raising temperatures to 15 million degrees Celsius, for long enough that atoms fused and produce neutrons. The sherwood program sponsored a series of Scylla machines at Los Alamos. The program began with 5 researchers and 100,000 in US funding in January 1952. By 1965, a total of 21 million had been spent on the program and staffing never reached above 65.
History of the Teller–Ulam design
The general principles of the "classical Super" design were public knowledge even before thermonuclear weapons were first tested. After President Truman ordered the crash program to develop the H-bomb in January 1950 the "Boston Daily Globe" published a cutaway description of a hypothetical H-bomb with the caption "Artist's conception of how H-bomb might work using atomic bomb as a mere "trigger" to generate enough heat to set up the H-bomb's "thermonuclear fusion" process."
Deuterium
The 62-ton Ivy Mike device built by the United States and exploded on 1 November 1952, was the first fully successful "hydrogen bomb" or thermonuclear bomb. In this context, it was the first bomb in which most of the energy released came from nuclear reaction stages that followed the primary nuclear fission stage of the atomic bomb. The Ivy Mike bomb was a factory-like building, rather than a deliverable weapon. At its center, a very large cylindrical, insulated vacuum flask or cryostat, held cryogenic liquid deuterium in a volume of about 1000 liters (160 kilograms in mass, if this volume had been completely filled). Then, a conventional atomic bomb (the "primary") at one end of the bomb was used to create the conditions of extreme temperature and pressure that were needed to set off the thermonuclear reaction.