Friday, September 28, 2012

The Soviets demonstrated


The Teller–Ulam design was for many years considered one of the top nuclear secrets, and even today it is not discussed in any detail by official publications with origins "behind the fence" of classification. United States Department of Energy (DOE) policy has been, HP Compaq HSTNN-OB52 Battery
and continues to be, that they do not acknowledge when "leaks" occur, because doing so would acknowledge the accuracy of the supposed leaked information.
Aside from images of the warhead casing, most information in the public domain about this design is relegated to a few terse statements by the DOE and the work of a few individual investigators. HP Compaq HSTNN-OB62 Battery
In 1972 the United States government declassified a statement that "The fact that in thermonuclear (TN) weapons, a fission 'primary' is used to trigger a TN reaction in thermonuclear fuel referred to as a 'secondary'", and in 1979 added, HP Compaq HSTNN-UB05 Battery
"The fact that, in thermonuclear weapons, radiation from a fission explosive can be contained and used to transfer energy to compress and ignite a physically separate component containing thermonuclear fuel." To this latter sentence they specified that "Any elaboration of this statement will be classified." HP Compaq HSTNN-UB11 Battery
The only statement which may pertain to the spark plug was declassified in 1991: "Fact that fissile and/or fissionable materials are present in some secondaries, material unidentified, location unspecified, use unspecified, and weapons undesignated." HP Compaq HSTNN-UB18 Battery
In 1998 the DOE declassified the statement that "The fact that materials may be present in channels and the term 'channel filler,' with no elaboration", which may refer to the polystyrene foam (or an analogous substance).[25]
Whether these statements vindicate some or all of the models presented above is up for interpretation, HP Compaq HSTNN-UB68 Battery
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 of course precise technical information has not been. HP Compaq HSTNN-UB69 Battery
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". HP Compaq HSTNN-W42C Battery
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. HP Compaq HSTNN-W42C-A Battery
Most of Morland's ideas about how the weapon worked were compiled from highly accessible sources—the drawings which 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, HP Compaq HSTNN-W42C-B Battery
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).[26] HP Compaq HSTNN-XB0E Battery
Morland eventually concluded that the "secret" was that the primary and secondary were kept separate and that radiation pressure from the primary compressed thesecondary before igniting it. When an early draft of the article, to be published in The Progressive magazine, HP Compaq HSTNN-XB11 Battery
was sent to the DOE after falling into the hands of a professor who was opposed to Morland's goal, the DOE requested that the article not be published, and pressed for a temporary injunction. The DOE argued that Morland's information was (1) likely derived from classified sources, HP Compaq HSTNN-XB18 Battery
(2) if not derived from classified sources, itself counted as "secret" information under the "born secret" clause of the 1954 Atomic Energy Act, and (3) was dangerous and would encourage nuclear proliferation.
Morland and his lawyers disagreed on all points, HP Compaq HSTNN-XB21 Battery
but the injunction was granted, as the judge in the case felt that it was safer to grant the injunction and allow Morland, et al., to appeal, which they did in United States v. The Progressive (1979).
Through a variety of more complicated circumstances, HP Compaq HSTNN-XB24 Battery
the DOE case began to wane as it became clear that some of the data they were attempting to claim as "secret" had been published in a students' encyclopedia a few years earlier. After another H-bomb speculator, Chuck Hansen, had his own ideas about the "secret" (quite different from Morland's) HP Compaq HSTNN-XB28 Battery
published in a Wisconsin newspaper, the DOE claimed that The Progressive case was moot, dropped its suit, and allowed the magazine to publish its article, which it did in November 1979. Morland had by then, however, changed his opinion of how the bomb worked, HP Compaq HSTNN-XB51 Battery
suggesting that a foam medium (the polystyrene) rather than radiation pressure was used to compress the secondary, and that in the secondary there was a spark plug of fissile material as well. He published these changes, based in part on the proceedings of the appeals trial, as a short erratum in The Progressive a month later. HP Compaq HSTNN-XB52 Battery
In 1981, Morland published a book about his experience, describing in detail the train of thought which led him to his conclusions about the "secret".[26][28]
Morland's work is interpreted as being at least partially correct because the DOE had sought to censor it, HP Compaq HSTNN-XB59 Battery
one of the few times they violated their usual approach of not acknowledging "secret" material which had been released; however, to what degree it lacks information, or has incorrect information, is not known with any confidence. HP Compaq HSTNN-XB61 Battery
The difficulty that a number of nations had in developing the Teller–Ulam design (even when they apparently understood the design, such as with the United Kingdom), makes it somewhat unlikely that this simple information alone is what provides the ability to manufacture thermonuclear weapons. HP Compaq HSTNN-XB62 Battery
Nevertheless, the ideas put forward by Morland in 1979 have been the basis for all the current speculation on the Teller–Ulam design.
There have been a few variations of the Teller–Ulam design suggested by sources claiming to have information from inside of the fence of classification. HP Compaq HSTNN-XB68 Battery

The Soviets demonstrated


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. HP Compaq HSTNNIB12 Battery
In 1954 work began at Aldermaston to develop the British fusion bomb, with Sir William Penney in charge of the project. British knowledge on how to make a thermonuclear fusion bomb was rudimentary, and at the time the United States was not exchanging any nuclear knowledge because of the Atomic Energy Act of 1946. HP Compaq HSTNN-IB16 Battery
However, the British were allowed to observe the American Castle testsand used sampling aircraft in the mushroom clouds, providing them with clear, direct evidence of the compression produced in the secondary stages by radiation implosion. HP Compaq HSTNN-IB18 Battery
Because of these difficulties, in 1955 British prime minister Anthony Eden agreed to a secret plan, whereby if the Aldermaston scientists failed or were greatly delayed in developing the fusion bomb, it would be replaced by an extremely large fission bomb. HP Compaq HSTNN-IB28 Battery
In 1957 the Operation Grapple tests were carried out. The first test, Green Granite was a prototype fusion bomb, but failed to produce equivalent yields compared to the Americans and Soviets, only achieving approximately 300 kilotons. HP Compaq HSTNN-IB51 Battery
The second test Orange Herald was the modified fission bomb and produced 700 kilotons—making it the largest fission explosion ever. At the time almost everyone (including the pilots of the plane that dropped it) thought that this was a fusion bomb. This bomb was put into service in 1958. HP Compaq HSTNN-IB52 Battery
A second prototype fusion bomb Purple Granite was used in the third test, but only produced approximately 150 kilotons.
A second set of tests was scheduled, with testing recommencing in September 1957. The first test was based on a "… new simpler design. HP Compaq HSTNN-IB55 Battery
A two stage thermonuclear bomb which had a much more powerful trigger". This test Grapple X Round C was exploded on November 8 and yielded approximately 1.8 megatons. On April 28, 1958 a bomb was dropped that yielded 3 megatons—Britain's most powerful test. HP Compaq HSTNN-IB62 Battery
Two final air burst tests on September 2 and September 11, 1958, dropped smaller bombs that yielded around 1 megaton each.
American observers had been invited to these kinds of tests. After their successful detonation of a megaton-range device HP Compaq HSTNN-LB05 Battery
(and thus demonstrating their practical understanding of the Teller–Ulam design "secret"), the United States agreed to exchange some of their nuclear designs with the United Kingdom, leading to the1958 US–UK Mutual Defence Agreement. HP Compaq HSTNN-LB08 Battery
Instead of continuing with their own design, the British were given access to the design of the smaller American Mk 28 warhead and were able to manufacture copies.
The People's Republic of China detonated its first H-Bomb using a Yu–Deng design June 17, 1967 ("Test No. 6"),HP Compaq HSTNN-LB0E Battery
a mere 32 months after detonating its first fission weapon (the shortest fission-to-fusion development in history), with a yield of 3.31 Mt.
The Yu–Deng design is different from the Teller–Ulam design. It doesn't use X-ray reflector, but refraction lens to achieve similar effect. HP Compaq HSTNN-LB11 Battery
India's first nuclear test occurred on May 18, 1974, which initially surprised the world. The first test, codename Smiling Buddha, was not a thermonuclear device according to the Bhabha Atomic Research Centre.[19] On May 11, 1998, India reportedly detonated a thermonuclear bomb in its Operation Shakti tests ("Shakti-1", specifically). HP Compaq HSTNN-LB51 Battery
Dr. Samar Mubarakmand asserted that Shakti-1 was a successful test, but if it was a thermonuclear device as claimed, then it failed to produce certain results that were to be expected of a thermonuclear device.[19]
Director for the 1998 test site preparations, Dr. K. Santhanam, HP Compaq HSTNN-LB52 Battery
reported the yield of thermonuclear explosion was lower than expected, although his statement has been disputed by other Indian scientists involved in the test.[20] Indian sources, using local data and citing a US Geologic Survey report compiling seismic data from 125 IRIS stations across the world, HP Compaq HSTNN-MB05 Battery
argue that the magnitudes suggested a combined yield of up to 60 kilotonnes, consistent with the Indian announced total yield of 56 kilotonnesHowever, several independent experts have reported lower yields for the nuclear test and remained skeptical about the claims,[19] and others have argued that even the claimed 50 kiloton yield was low for confirmation of a thermonuclear design. HP Compaq HSTNN-OB06 Battery

The Soviets demonstrated


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. HP Compaq HSTNNIB12 Battery
In 1954 work began at Aldermaston to develop the British fusion bomb, with Sir William Penney in charge of the project. British knowledge on how to make a thermonuclear fusion bomb was rudimentary, and at the time the United States was not exchanging any nuclear knowledge because of the Atomic Energy Act of 1946. HP Compaq HSTNN-IB16 Battery
However, the British were allowed to observe the American Castle testsand used sampling aircraft in the mushroom clouds, providing them with clear, direct evidence of the compression produced in the secondary stages by radiation implosion. HP Compaq HSTNN-IB18 Battery
Because of these difficulties, in 1955 British prime minister Anthony Eden agreed to a secret plan, whereby if the Aldermaston scientists failed or were greatly delayed in developing the fusion bomb, it would be replaced by an extremely large fission bomb. HP Compaq HSTNN-IB28 Battery
In 1957 the Operation Grapple tests were carried out. The first test, Green Granite was a prototype fusion bomb, but failed to produce equivalent yields compared to the Americans and Soviets, only achieving approximately 300 kilotons. HP Compaq HSTNN-IB51 Battery
The second test Orange Herald was the modified fission bomb and produced 700 kilotons—making it the largest fission explosion ever. At the time almost everyone (including the pilots of the plane that dropped it) thought that this was a fusion bomb. This bomb was put into service in 1958. HP Compaq HSTNN-IB52 Battery
A second prototype fusion bomb Purple Granite was used in the third test, but only produced approximately 150 kilotons.
A second set of tests was scheduled, with testing recommencing in September 1957. The first test was based on a "… new simpler design. HP Compaq HSTNN-IB55 Battery
A two stage thermonuclear bomb which had a much more powerful trigger". This test Grapple X Round C was exploded on November 8 and yielded approximately 1.8 megatons. On April 28, 1958 a bomb was dropped that yielded 3 megatons—Britain's most powerful test. HP Compaq HSTNN-IB62 Battery
Two final air burst tests on September 2 and September 11, 1958, dropped smaller bombs that yielded around 1 megaton each.
American observers had been invited to these kinds of tests. After their successful detonation of a megaton-range device HP Compaq HSTNN-LB05 Battery
(and thus demonstrating their practical understanding of the Teller–Ulam design "secret"), the United States agreed to exchange some of their nuclear designs with the United Kingdom, leading to the1958 US–UK Mutual Defence Agreement. HP Compaq HSTNN-LB08 Battery
Instead of continuing with their own design, the British were given access to the design of the smaller American Mk 28 warhead and were able to manufacture copies.
The People's Republic of China detonated its first H-Bomb using a Yu–Deng design June 17, 1967 ("Test No. 6"),HP Compaq HSTNN-LB0E Battery
a mere 32 months after detonating its first fission weapon (the shortest fission-to-fusion development in history), with a yield of 3.31 Mt.
The Yu–Deng design is different from the Teller–Ulam design. It doesn't use X-ray reflector, but refraction lens to achieve similar effect. HP Compaq HSTNN-LB11 Battery
India's first nuclear test occurred on May 18, 1974, which initially surprised the world. The first test, codename Smiling Buddha, was not a thermonuclear device according to the Bhabha Atomic Research Centre.[19] On May 11, 1998, India reportedly detonated a thermonuclear bomb in its Operation Shakti tests ("Shakti-1", specifically). HP Compaq HSTNN-LB51 Battery
Dr. Samar Mubarakmand asserted that Shakti-1 was a successful test, but if it was a thermonuclear device as claimed, then it failed to produce certain results that were to be expected of a thermonuclear device.[19]
Director for the 1998 test site preparations, Dr. K. Santhanam, HP Compaq HSTNN-LB52 Battery
reported the yield of thermonuclear explosion was lower than expected, although his statement has been disputed by other Indian scientists involved in the test.[20] Indian sources, using local data and citing a US Geologic Survey report compiling seismic data from 125 IRIS stations across the world, HP Compaq HSTNN-MB05 Battery
argue that the magnitudes suggested a combined yield of up to 60 kilotonnes, consistent with the Indian announced total yield of 56 kilotonnesHowever, several independent experts have reported lower yields for the nuclear test and remained skeptical about the claims,[19] and others have argued that even the claimed 50 kiloton yield was low for confirmation of a thermonuclear design. HP Compaq HSTNN-OB06 Battery

The Soviets demonstrated


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. HP Compaq HSTNNIB12 Battery
In 1954 work began at Aldermaston to develop the British fusion bomb, with Sir William Penney in charge of the project. British knowledge on how to make a thermonuclear fusion bomb was rudimentary, and at the time the United States was not exchanging any nuclear knowledge because of the Atomic Energy Act of 1946. HP Compaq HSTNN-IB16 Battery
However, the British were allowed to observe the American Castle testsand used sampling aircraft in the mushroom clouds, providing them with clear, direct evidence of the compression produced in the secondary stages by radiation implosion. HP Compaq HSTNN-IB18 Battery
Because of these difficulties, in 1955 British prime minister Anthony Eden agreed to a secret plan, whereby if the Aldermaston scientists failed or were greatly delayed in developing the fusion bomb, it would be replaced by an extremely large fission bomb. HP Compaq HSTNN-IB28 Battery
In 1957 the Operation Grapple tests were carried out. The first test, Green Granite was a prototype fusion bomb, but failed to produce equivalent yields compared to the Americans and Soviets, only achieving approximately 300 kilotons. HP Compaq HSTNN-IB51 Battery
The second test Orange Herald was the modified fission bomb and produced 700 kilotons—making it the largest fission explosion ever. At the time almost everyone (including the pilots of the plane that dropped it) thought that this was a fusion bomb. This bomb was put into service in 1958. HP Compaq HSTNN-IB52 Battery
A second prototype fusion bomb Purple Granite was used in the third test, but only produced approximately 150 kilotons.
A second set of tests was scheduled, with testing recommencing in September 1957. The first test was based on a "… new simpler design. HP Compaq HSTNN-IB55 Battery
A two stage thermonuclear bomb which had a much more powerful trigger". This test Grapple X Round C was exploded on November 8 and yielded approximately 1.8 megatons. On April 28, 1958 a bomb was dropped that yielded 3 megatons—Britain's most powerful test. HP Compaq HSTNN-IB62 Battery
Two final air burst tests on September 2 and September 11, 1958, dropped smaller bombs that yielded around 1 megaton each.
American observers had been invited to these kinds of tests. After their successful detonation of a megaton-range device HP Compaq HSTNN-LB05 Battery
(and thus demonstrating their practical understanding of the Teller–Ulam design "secret"), the United States agreed to exchange some of their nuclear designs with the United Kingdom, leading to the1958 US–UK Mutual Defence Agreement. HP Compaq HSTNN-LB08 Battery
Instead of continuing with their own design, the British were given access to the design of the smaller American Mk 28 warhead and were able to manufacture copies.
The People's Republic of China detonated its first H-Bomb using a Yu–Deng design June 17, 1967 ("Test No. 6"),HP Compaq HSTNN-LB0E Battery
a mere 32 months after detonating its first fission weapon (the shortest fission-to-fusion development in history), with a yield of 3.31 Mt.
The Yu–Deng design is different from the Teller–Ulam design. It doesn't use X-ray reflector, but refraction lens to achieve similar effect. HP Compaq HSTNN-LB11 Battery
India's first nuclear test occurred on May 18, 1974, which initially surprised the world. The first test, codename Smiling Buddha, was not a thermonuclear device according to the Bhabha Atomic Research Centre.[19] On May 11, 1998, India reportedly detonated a thermonuclear bomb in its Operation Shakti tests ("Shakti-1", specifically). HP Compaq HSTNN-LB51 Battery
Dr. Samar Mubarakmand asserted that Shakti-1 was a successful test, but if it was a thermonuclear device as claimed, then it failed to produce certain results that were to be expected of a thermonuclear device.[19]
Director for the 1998 test site preparations, Dr. K. Santhanam, HP Compaq HSTNN-LB52 Battery
reported the yield of thermonuclear explosion was lower than expected, although his statement has been disputed by other Indian scientists involved in the test.[20] Indian sources, using local data and citing a US Geologic Survey report compiling seismic data from 125 IRIS stations across the world, HP Compaq HSTNN-MB05 Battery
argue that the magnitudes suggested a combined yield of up to 60 kilotonnes, consistent with the Indian announced total yield of 56 kilotonnesHowever, several independent experts have reported lower yields for the nuclear test and remained skeptical about the claims,[19] and others have argued that even the claimed 50 kiloton yield was low for confirmation of a thermonuclear design. HP Compaq HSTNN-OB06 Battery
The Teller–Ulam design was for many years considered one of the top nuclear secrets, and even today it is not discussed in any detail by official publications with origins "behind the fence" of classification. United States Department of Energy (DOE) policy has been, HP Compaq HSTNN-OB52 Battery
and continues to be, that they do not acknowledge when "leaks" occur, because doing so would acknowledge the accuracy of the supposed leaked information.
Aside from images of the warhead casing, most information in the public domain about this design is relegated to a few terse statements by the DOE and the work of a few individual investigators. HP Compaq HSTNN-OB62 Battery
In 1972 the United States government declassified a statement that "The fact that in thermonuclear (TN) weapons, a fission 'primary' is used to trigger a TN reaction in thermonuclear fuel referred to as a 'secondary'", and in 1979 added, HP Compaq HSTNN-UB05 Battery
"The fact that, in thermonuclear weapons, radiation from a fission explosive can be contained and used to transfer energy to compress and ignite a physically separate component containing thermonuclear fuel." To this latter sentence they specified that "Any elaboration of this statement will be classified." HP Compaq HSTNN-UB11 Battery
The only statement which may pertain to the spark plug was declassified in 1991: "Fact that fissile and/or fissionable materials are present in some secondaries, material unidentified, location unspecified, use unspecified, and weapons undesignated." HP Compaq HSTNN-UB18 Battery
In 1998 the DOE declassified the statement that "The fact that materials may be present in channels and the term 'channel filler,' with no elaboration", which may refer to the polystyrene foam (or an analogous substance).[25]
Whether these statements vindicate some or all of the models presented above is up for interpretation, HP Compaq HSTNN-UB68 Battery
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 of course precise technical information has not been. HP Compaq HSTNN-UB69 Battery
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". HP Compaq HSTNN-W42C Battery
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. HP Compaq HSTNN-W42C-A Battery
Most of Morland's ideas about how the weapon worked were compiled from highly accessible sources—the drawings which 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, HP Compaq HSTNN-W42C-B Battery
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).[26] HP Compaq HSTNN-XB0E Battery
Morland eventually concluded that the "secret" was that the primary and secondary were kept separate and that radiation pressure from the primary compressed thesecondary before igniting it. When an early draft of the article, to be published in The Progressive magazine, HP Compaq HSTNN-XB11 Battery
was sent to the DOE after falling into the hands of a professor who was opposed to Morland's goal, the DOE requested that the article not be published, and pressed for a temporary injunction. The DOE argued that Morland's information was (1) likely derived from classified sources, HP Compaq HSTNN-XB18 Battery
(2) if not derived from classified sources, itself counted as "secret" information under the "born secret" clause of the 1954 Atomic Energy Act, and (3) was dangerous and would encourage nuclear proliferation.
Morland and his lawyers disagreed on all points, HP Compaq HSTNN-XB21 Battery
but the injunction was granted, as the judge in the case felt that it was safer to grant the injunction and allow Morland, et al., to appeal, which they did in United States v. The Progressive (1979).
Through a variety of more complicated circumstances, HP Compaq HSTNN-XB24 Battery
the DOE case began to wane as it became clear that some of the data they were attempting to claim as "secret" had been published in a students' encyclopedia a few years earlier. After another H-bomb speculator, Chuck Hansen, had his own ideas about the "secret" (quite different from Morland's) HP Compaq HSTNN-XB28 Battery
published in a Wisconsin newspaper, the DOE claimed that The Progressive case was moot, dropped its suit, and allowed the magazine to publish its article, which it did in November 1979. Morland had by then, however, changed his opinion of how the bomb worked, HP Compaq HSTNN-XB51 Battery
suggesting that a foam medium (the polystyrene) rather than radiation pressure was used to compress the secondary, and that in the secondary there was a spark plug of fissile material as well. He published these changes, based in part on the proceedings of the appeals trial, as a short erratum in The Progressive a month later. HP Compaq HSTNN-XB52 Battery
In 1981, Morland published a book about his experience, describing in detail the train of thought which led him to his conclusions about the "secret".[26][28]
Morland's work is interpreted as being at least partially correct because the DOE had sought to censor it, HP Compaq HSTNN-XB59 Battery
one of the few times they violated their usual approach of not acknowledging "secret" material which had been released; however, to what degree it lacks information, or has incorrect information, is not known with any confidence. HP Compaq HSTNN-XB61 Battery
The difficulty that a number of nations had in developing the Teller–Ulam design (even when they apparently understood the design, such as with the United Kingdom), makes it somewhat unlikely that this simple information alone is what provides the ability to manufacture thermonuclear weapons. HP Compaq HSTNN-XB62 Battery
Nevertheless, the ideas put forward by Morland in 1979 have been the basis for all the current speculation on the Teller–Ulam design.
There have been a few variations of the Teller–Ulam design suggested by sources claiming to have information from inside of the fence of classification. HP Compaq HSTNN-XB68 Battery

Two special variations


Two special variations exist which will be discussed in a further section: HP Compaq HSTNN-DB05 Battery
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. HP Compaq HSTNN-DB06 Battery
Most bombs do not apparently have tertiary "stages" —that is, third compression stage(s), which are additional fusion stages compressed by a previous fusion stage (the fissioning of the last blanket of uranium, which provides about half the yield in large bombs, does not count as a "stage" in this terminology). HP Compaq HSTNN-DB0E Battery
The U.S. tested three-stage bombs in several explosions (see Operation Redwing) but is only thought to have fielded one such tertiary model, i.e., a bomb in which a fission stage, followed by a fusion stage, finally compresses yet another fusion stage. HP Compaq HSTNN-DB11 Battery
This U.S. design was the heavy but highly efficient (i.e.,nuclear weapon yield per unit bomb weight) 25 Mt B41 nuclear bomb[15]. The Soviet Union is thought to have used multiple stages (including more than one tertiary fusion stages) in their 50 megaton (100 Mt in intended use) Tsar Bomba HP Compaq HSTNN-DB16 Battery
(however, as with other bombs, the fissionable jacket could be replaced with lead in such a bomb, and in this one, for demonstration, it was). If any hydrogen bombs have been made from configurations other than those based on the Teller–Ulam design, the fact of it is not publicly known. HP Compaq HSTNN-DB28 Battery
(A possible exception to this is the Soviet early Sloika design).
In essence, the Teller–Ulam configuration relies on at least two instances of implosion occurring: first, the conventional (chemical) explosives in the primary would compress the fissile core, HP Compaq HSTNN-DB29 Battery
resulting in a fission explosion many times more powerful than that which chemical explosives could achieve alone (first stage). Second, the radiation from the fissioning of the primary would be used to compress and ignite the secondary fusion stage, resulting in a fusion explosion many times more powerful than the fission explosion alone. HP Compaq HSTNN-DB67 Battery
This chain of compression could then be continued with an arbitrary number of tertiary fision stages. Finally, efficient bombs (but not so-called neutron bombs) end with the fissioning of the final natural uranium tamper, something which could not normally be achieved without the neutron flux provided by the fusion reactions in secondary or tertiary stages. HP Compaq HSTNN-FB05 Battery
Such designs can be scaled up to an arbitrary strength (with apparently as many fusion stages as desired), potentially to the level of a "doomsday device." However, usually such weapons were not more than a dozen megatons, which was generally considered enough to destroy even most hardened practical targets HP Compaq HSTNN-FB18 Battery
(for example, a control facility such as the Cheyenne Mountain Operations Center). Even such large bombs have been replaced by smaller-yield bunker buster type nuclear bombs, see also nuclear bunker buster.
As discussed above, for destruction of cities and non-hardened targets, HP Compaq HSTNN-FB51 Battery
breaking the mass of a single missile payload down into smaller MIRV bombs, in order to spead the energy of the explosions into a "pancake" area, is far more efficient in terms of area-destruction per unit of bomb energy. This also applies to single bombs deliverable by cruise missile or other system, such as a bomber, HP Compaq HSTNN-FB52 Battery
resulting in most operational warheads in the U.S. program having yields of less than 500 kilotons.
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. HP Compaq HSTNN-I04C Battery
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 Manhattan Project 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. HP Compaq HSTNN-I12C Battery
Stanislaw Ulam, a coworker of Teller's, made the first key conceptual leaps towards a workable fusion design. Ulam's two innovations which rendered the fusion bomb practical were that compression of the thermonuclear fuel before extreme heating was a practical path towards the conditions needed for fusion, HP Compaq HSTNN-I39C Battery
and the idea of staging or placing a separate thermonuclear component outside a fission primary component, and somehow using the primary to compress the secondary. Teller then realized that the gamma and X-ray radiation produced in the primary could transfer enough energy into the secondary to create a successful implosion and fusion burn, HP Compaq HSTNN-I40C Battery
if the whole assembly was wrapped in a hohlraum or radiation case. Teller and his various proponents and detractors later disputed the degree to which Ulam had contributed to the theories underlying this mechanism. Indeed, shortly before his death, and in a last-ditch effort to discredit Ulam's contributions, HP Compaq HSTNN-I44C Battery
Teller claimed that one of his own "graduate students" had proposed the mechanism.
The "George" shot of Operation Greenhouse in 1951 tested the basic concept for the first time on a very small scale, raising expectations to a near certainty that the concept would work. HP Compaq HSTNN-I44C-A Battery
On November 1, 1952, the Teller–Ulam configuration was tested at full scale in the "Ivy Mike" shot at an island in the Enewetak Atoll, with a yield of 10.4 megatons (over 450 times more powerful than the bomb dropped on Nagasaki during World War II). HP Compaq HSTNN-I44C-B Battery
The device, dubbed the Sausage, used an extra-large fission bomb as a "trigger" and liquid deuterium—kept in its liquid state by 20short tons (18 metric tons) of cryogenic equipment—as its fusion fuel, and weighed around 80 short tons (70 metric tons) altogether. HP Compaq HSTNN-I45C Battery
The liquid deuterium fuel of Ivy Mike was impractical for a deployable weapon, and the next advance was to use a solid lithium deuteride fusion fuel instead. In 1954 this was tested in the "Castle Bravo" shot (the device was code-named the Shrimp), which had a yield of 15 megatons (2.5 times higher than expected) and is the largest U.S. bomb ever tested. HP Compaq HSTNN-I45C-A Battery
Efforts in the United States soon shifted towards developing miniaturized Teller–Ulam weapons which could easily outfit intercontinental ballistic missiles andsubmarine-launched ballistic missiles. By 1960, with the W47 warhead[16] deployed on Polaris ballistic missile submarines, HP Compaq HSTNN-I45C-B Battery
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, HP Compaq HSTNN-I48C-A Battery
when versions of the Teller–Ulam design were created which could fit ten or more warheads on the end of a small MIRVed missile (see the section on the W88 below).[4]
The first Soviet fusion design, developed by Andrei Sakharov and Vitaly Ginzburg in 1949 (before the Soviets had a working fission bomb), HP Compaq HSTNN-I48C-B Battery
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"). HP Compaq HSTNN-I49C Battery
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). HP Compaq HSTNN-I50C-B Battery
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, HP Compaq HSTNN-I54C Battery
along with the fission core, multiplying the bulk of chemical explosives needed substantially.
Their first Sloika design test, RDS-6s, was detonated in 1953 with a yield equivalent to 400 kilotons of TNT (15%–20% from fusion). Attempts to use a Sloikadesign to achieve megaton-range results proved unfeasible. HP Compaq HSTNN-I64C-5 Battery
After the U.S. tested the "Ivy Mike" bomb in November 1952, proving that a multimegaton bomb could be created, the Soviets searched for an additional design. The "Second Idea", as Sakharov referred to it in his memoirs, HP Compaq HSTNN-I65C-5 Battery
was a previous proposal by Ginzburg in November 1948 to use lithium deuteride in the bomb, which would, in the course of being bombarded by neutrons, produce tritium and free deuterium.[17] In late 1953 physicist Viktor Davidenko achieved the first breakthrough, that of keeping the primary and secondary parts of the bombs in separate pieces ("staging"). HP Compaq HSTNN-IB05 Battery
The next breakthrough was discovered and developed by Sakharov and Yakov Zel'dovich, that of using the X-rays from the fission bomb to compress the secondarybefore fusion ("radiation implosion"), in early 1954. Sakharov's "Third Idea", as the Teller–Ulam design was known in the USSR, was tested in the shot "RDS-37" in November 1955 with a yield of 1.6 megatons. HP Compaq HSTNN-IB08 Battery