Hydrogen Bomb

Ivy Mike

Castle Bravo

Monday, May 24, 2010

Hydrogen Bomb





~Hydrogen bombs are also known for a fusion bomb. Hydrogen bomb goes through a stage of nuclear fusion. Nuclear fusion is the process by which multiple atomic nuclei joins together to form a heavier nucleus. In other words, it is involving many atoms to come together at once to make it at a very high density. The two nuclei that are coming together must have a lower mass than iron; it will release energy while the fusion of the nuclei absorbs energy. Its pretty much two protons having to be brought close enough for the weak forces to convert the proton into a neutron to form a deuterium.

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~A deuterium is a stable isotope of hydrogen with natural abundance in the oceans of the Earth. The nucleus of deuterium contains one proton and one neutron, while a regular hydrogen element does not contain a neutron in the nucleus. During World War II, scientists were using heavy water for a nuclear reactor design since the heavy water had deuterium hydrogen. It allowed them to produce plutonium for an atomic bomb and later a hydrogen bomb.

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~A fusion reaction produces all but the lightest elements in a process called nucleosynthesis. When a fusion reaction is a sustain, uncontrolled chain, it can end up to be a thermonuclear explosion. But it also has the potential to be controlled and used as a energy source such as electricity. It takes a considerable energy to force the nuclei to fuse to create the energy or form hydrogen. The end result is it releasing more energy then was used to put them together, this is called exothermic process.

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~The idea to start forming a hydrogen bomb or fusion bomb was in the stars. Nuclear fusion occurs naturally in stars. People were just trying to make an artificial fusion out of the knowledge about the stars nuclear fusion. When the scientists figured out how to manipulate the nuclear fusion, the only problem was they could not control the energy of the output. Not long after nuclear transmutation research was conducted. The research into nuclear fusion was mostly for military purposes only in the 1940s. When the 1950s came, it became a public purpose.


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Castle Bravo


~Castle Bravo was a code name given to the first test of the hydrogen bomb that was set off on March 1, 1954 at Bikini Atoll, Marshall Island. But the fallout from the detonation had poisoned the islanders who inhabited the test sites, including a crew of Daigo Fukuryu Maru, a Japanese fishing boat which created international concern about atmospheric thermonuclear testing. The bomb had used lithium deuteride instead of cryogenic liquid deuterium tritium which was used at the Ivy Mike experiment.
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~The Soviet Union had previously used lithium deuteride in a nuclear bomb as well which was nicknamed "Alarm Clock" in 1953. It was not officially a true hydrogen bomb, but was yield mostly from its boostered fission reactions, and was limited a yield of 400 kt. While the Teller-Ulam based Ivy Mike device yield at 10.4 MT, and Castle Bravo had a 15 MT. Castle Bravo was the most powerful nuclear device ever detonated by the United States since it had 15 Megatons. Since it was the most powerful it led to the most significant accidental radiological contamination ever caused by the United States. Castle Bravo was about 1,200 times more powerful than each of the atomic bombs taht were dropped on Hiroshima and Nagasaki during World War ll. But the largest nuclear explosion ever produced was conducted by the Soviet Union which was about 50 MT, the Tsar Bomba.
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~When Castle Bravo was detonated, it formed a fireball almost four and a half miles which is about 7km across within a second. The fireball was visible on the Kwajalein atoll over 250 miles away. Castle Bravo had left a crater of 6,500 feet in diameter and 250 ft deep. The mushroom cloud of the bomb reached a height of 47,000 feet and 7 miles in diameter in about a minute; then not longer reached a height of 130,000 feet and 62 miles in diameter in less than 10mins and was expanding at more than 4miles per minute. the cloud contaminted more than seven thousand square miles surrounding Pacific Ocean including the surrounding small islands likie Rongerik, Rongelap and Utirik.
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~The yield of 15 megatons was two and a half times more than what was expected. The cause of the high yield was a error made by designers of the bomb at Los Alamos National Laboratory. It was expected that lithium-6 isotope would absorb a neutron from the fissioning plutonium and emit an alpha particle and tritium in the process which was then fuse with the deuterium and increased the yield. When lithium-7 isotope is bombarded with high energy neutrons, it absorbs a neutron then decomposes to form an alpha particle, another nuetron and a tritium nucleus. Since the lithium-6 isotope did not do what it was suppose to, which increased the tritium along with the deuterium, which reacts with creating more neutrons than expected, causing a far more fissioning of the uranium tamper.
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~The fission reactions of the natural uranium tamper produced a large amount of fallout. That and the more larger than expected yield and major wind shifts, producing a large number of very serious consequences. The decision to fire the bomb was Dr. Alvin C. Graves, he had total authority over firing the weapon, even above that of the military commander of Operation Castle. In result Dr. Grave had received an exposure of 400 rontgens in the 1946 Los Alamos accident in which his personal friend. Dr. Louis Stolin had died from the radiation exposure, just because of the prevailing winds. Radioactive fallout was spread eastward onto Rongelap and Rongerik atolls, many Marshall Island natives suffered from birth defects and received compensation from the U.S. Federal government. Lucky Dragon No. 5 came in direct contact with the fallout which caused the whole crew to grow ill and one later died. Unanticipated fallout and radiation affected many of the vessels and personnel involved in the test which had trapped them in bunkers. Sixteen crew members of the aircraft USS Bairoko received beta burns and increased cancer rate. Fallout spread radioactive materials as far as Australia, India and Japan and part of the US and Europe. Castle Bravo had quickly became an international incident, which had called for a ban on the atmospheric testing of thermonuclear devices.
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Ivy Mike



~Ivy Mike was the codename given to the first nuclear test of a fusion device by the United States. The major part of the explosive yield came from nuclear fusion. Ivy Mike was detonated on November 1, 1952 on Enewetak, an atoll in the Pacific Ocean. This device was part of the Teller-Ulam design, a staged fusion bomb and generally considered the first successful test of a hydrogen bomb. The physical size and fusion fuel type of the Mike bomb was not suitable for use as a thermonuclear weapon. it was an extremely conservative experiment to validate the concepts use for multi-megaton detonations. Later resulted in the making of a simplified and lightened bomb version, the EC-16 and scheduled to be tested in opperation Castle Yankee which was codenamed "Shrimp". But Shrimp was cancelled when the Castle Bravo bomb was tested successfully.

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~The device was designed by Richard Garwin, a student of Enrico Fermi. He was suggested by the design created by Edward Teller; the Teller-Ulam design. The primary stage was a TX-5 boosted fission bomb in a separate space atop the assembly, while the secondary fusion stage used liquid deuterium despite the diffculty of handling this material. Running down the center of the flask which was held by a cylindrical rod of plutonium to ignite the fusion reaction. Surrounding the whole assembly was a five-ton natural uranium tamper. The outside of the tamper was lined with sheets of lead and polyethylene foam which formed a radiation channel to conduct X-rays from the primary to secondary. The outermost layer was a steel casing that was 10-12 inches thick. It was nicknamed "Sausage", measured 80 inches in diameter and 244 inches in height and weighed about 54 tons. But the entire Mike bomb weighed 82 short tons.

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~The test was carried out at 7:15 A.m on November 1, 1952 and produced a yield in the range of 10.4-12 Megatons.The 77% of the final yield came from the fast fission of the uranium tamper, which meant the device produced large amounts of fallout. The fireball was approximately 3.25 miles wide and the mushroom cloud rose to an altitude of 57,000 feet in less than two minutes. A minute later it had reached 108,000 feet before stabilizing at 136,000 feet with the top eventually spreading out to a 100miles in diameter with a stem of 20miles wide. The outcome of the blast created a crater 6,240 feet in diameter and 164 feet deep where Elugelab had once been. The blast and water waves from the explosion stripped the test islands clean of vegetation. Irradiated coral debris fell upon ships stationed 30miles from the last and immediate area around the atoll was heavily contaminated for some time.

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Teller-Ulam Design



~Teller-Ulam design is a nuclear weapon design concept used in most of the world's nuclear weapons. The design employs hydrogen fusion to generate neutrons, most applications the bulk of its destructive energy that comes from uranium fission and not hydrogen fusion. It is named after its two chief contributors, Edward Teller and Stanislaw Ulam who developed it in 1951, for use by the United States. Was first used in multi megaton range thermonuclear weapons.

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There are a few features in the design that had to happen when the hydrogen bomb went off.



1) Separation of stages into a triggering primary explosive and a much more powerful secondary explosive.



2)Compression of the secondary by X-rays coming from the nuclear fission in the primary. It is known as radiation implosion of the secondary.



3)Heating of the secondary, after cold compression by the second fission explosion.

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~The radiation implosion mechanism is a heat engine exploiting the temperature difference between the hot radiation channel that is surrounding the secondary that is relatively cool. The temperature difference is maintained by a massive heat barrier that is called the "pusher" or an implosion tamper. The pusher can increase the compression of the secondary if it is made of uranium. It undergoes fission by capturing the neutrons produced by fusion. In most of the Teller-Ulam weapons, fission of the pusher dominates the explosion and produces radioactive fission product fallout. The first bomb that was ever used by this principle was the Ivy Mike in 1952.

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~The basic principle of the Teller Ulam configuration is the idea that different parts of a thermonuclear weapon can be chained together in stages, which means when one goes off, the next stage will set off along with it. Surrounding the components is a radiation case, a contrainer which traps the first stage energy inside temporarily. The outside casing of the bomb is only direct visual evidence publicly available of any thermonuclear bomb component's configuration. The primary is a standard implosion method of a fission bomb with a core boosted by a small amounts of fusion fuel. the fusion fuel releases excress neutrons when heated and compressed, inducing additional fission. The secondary is wrapped in many layers, around it is a pusher-tamper, which is a heavy layer of lead that helps compress the fusion fuel. Inside the secondary is the fusion fuel which is usually a form of lithium deuteride. The dry fuel, when bombarded by neutrons, produces tritium which would undergo nuclear fusion, along with the deuterium present in the mixture. Separating the secondary from the primary is the interstage. This can produce three different type of energy, expanding hot gases from high explosive charges which implode the primary, the electromagnetic radiation and the neutrons from the primary's nuclear detonation. Interstage is ment for accurately modulating the transfer of energy from the primary to the secondary.
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