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W47
The W47 was an American thermonuclear warhead used on the Polaris A-1 sub-launched ballistic missile system. Various models were in service from 1960 through the end of 1974. The warhead was developed by the Lawrence Radiation Laboratory between 1957 and 1960. The W47 was in diameter and long, and weighed in the Y1 model and in the Y2 model. The Y1 model had design yield of 600 kilotons and the Y2 model had a doubled design yield of 1.2 megatons. The W47 was the first warhead with a new, miniaturized pit. The aerodynamic flare at the base provided stability of orientation during descent. Two small rocket motors were used to spin the warhead for better stability and symmetry during reentry. Design Declassified British documents indicate that the W47 contained of plutonium, of uranium, of lithium deuteride and of tritium. Live fire testing The W47 is the only US ICBM or SLBM warhead to have been live fired in an atmospheric missile and warhead test, on May 6, 1962. This ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UGM-27 Polaris
The UGM-27 Polaris missile was a two-stage solid-fueled nuclear-armed submarine-launched ballistic missile (SLBM). As the United States Navy's first SLBM, it served from 1961 to 1980. In the mid-1950s the Navy was involved in the Jupiter missile project with the U.S. Army, and had influenced the design by making it squat so it would fit in submarines. However, they had concerns about the use of liquid fuel rockets on board ships, and some consideration was given to a solid fuel version, Jupiter S. In 1956, during an anti-submarine study known as Project Nobska, Edward Teller suggested that very small hydrogen bomb warheads were possible. A crash program to develop a missile suitable for carrying such warheads began as Polaris, launching its first shot less than four years later, in February 1960. As the Polaris missile was fired underwater from a moving platform, it was essentially invulnerable to counterattack. This led the Navy to suggest, starting around 1959, that they be g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Weapon Design
Nuclear weapon designs are physical, chemical, and engineering arrangements that cause the physics package of a nuclear weapon to detonate. There are three existing basic design types: * pure fission weapons, the simplest and least technically demanding, were the first nuclear weapons built and have so far been the only type ever used in warfare (by the United States on Empire of Japan, Japan during World War II, WWII). * boosted fission weapons increase yield beyond that of the implosion design by using small quantities of fusion fuel to enhance the fission chain reaction. Boosting can more than double the weapon's fission energy yield. * thermonuclear weapon, staged thermonuclear weapons are essentially arrangements of two or more "stages", most usually two. The first stage is normally a boosted fission weapon as above (except for the earliest thermonuclear weapons, which used a pure fission weapon instead). Its detonation causes it to shine intensely with x-radiation, which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermonuclear Bomb
A thermonuclear weapon, fusion weapon or hydrogen bomb (H bomb) is a second-generation nuclear weapon design. Its greater sophistication affords it vastly greater destructive power than first-generation nuclear bombs, a more compact size, a lower mass, or a combination of these benefits. Characteristics of nuclear fusion reactions make possible the use of non-fissile depleted uranium as the weapon's main fuel, thus allowing more efficient use of scarce fissile material such as uranium-235 () or plutonium-239 (). The first full-scale thermonuclear test was carried out by the United States in 1952; the concept has since been employed by most of the world's nuclear powers in the design of their weapons. Modern fusion weapons consist essentially of two main components: a nuclear fission primary stage (fueled by or ) and a separate nuclear fusion secondary stage containing thermonuclear fuel: the heavy hydrogen isotopes deuterium and tritium, or in modern weapons lithium deuteride. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operation Dominic
Operation Dominic was a series of 31 nuclear test explosions with a total yield conducted in 1962 by the United States in the Pacific. This test series was scheduled quickly, in order to respond in kind to the Soviet resumption of testing after the tacit 1958–1961 test moratorium. Most of these shots were conducted with free-fall bombs dropped from B-52 bomber aircraft. Twenty of these shots were to test new weapons designs; six to test weapons effects; and several shots to confirm the reliability of existing weapons. The Thor missile was also used to lift warheads into near-space to conduct high-altitude nuclear explosion tests; these shots were collectively called Operation Fishbowl. Operation Dominic occurred during a period of high Cold War tension between the United States and the Soviet Union, since the Cuban Bay of Pigs Invasion had occurred not long before. Nikita Khrushchev announced the end of a three-year moratorium on nuclear testing on 30 August 1961, and Sovi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Nuclear Weapons
This is a list of nuclear weapons listed according to country of origin, and then by type within the states. United States US nuclear weapons of all types – bombs, warheads, shells, and others – are numbered in the same sequence starting with the Mark 1 and () ending with the W-91 (which was canceled prior to introduction into service). All designs which were formally intended to be weapons at some point received a number designation. Pure test units which were experiments (and not intended to be weapons) are not numbered in this sequence. Early weapons were very large and could only be used as free fall bombs. These were known by "Mark" designators, like the Mark 4 which was a development of the Fat Man weapon. As weapons became more sophisticated they also became much smaller and lighter, allowing them to be used in many roles. At this time the weapons began to receive designations based on their role; bombs were given the prefix "B", while the same warhead used in other r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pit (nuclear Weapon)
The pit, named after the hard core found in fruits such as peaches and apricots, is the core of an implosion nuclear weapon – the fissile material and any neutron reflector or tamper bonded to it. Some weapons tested during the 1950s used pits made with U-235 alone, or in composite with plutonium, but all-plutonium pits are the smallest in diameter and have been the standard since the early 1960s. Pit designs Christy pits The pits of the first nuclear weapons were solid, with an ''urchin'' neutron initiator in their center. The Gadget and Fat Man used pits made of 6.2 kg of solid hot pressed plutonium-gallium alloy (at 400 °C and 200 MPa in steel dies – and ) half-spheres of diameter, with a internal cavity for the initiator. The Gadget's pit was electroplated with 0.13 mm of silver; the layer, however, developed blistering and the blisters had to be ground and plated with gold leaf before the test. The Fat Man pit, and those of subsequent models, were ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lawrence Livermore National Laboratory
Lawrence Livermore National Laboratory (LLNL) is a federal research facility in Livermore, California, United States. The lab was originally established as the University of California Radiation Laboratory, Livermore Branch in 1952 in response to the detonation of the first atomic bomb by the Soviet Union during the Cold War. It later became autonomous in 1971 and was designated a national laboratory in 1981. A federally funded research and development center, Lawrence Livermore Lab is primarily funded by the U.S. Department of Energy and it is managed privately and operated by Lawrence Livermore National Security, LLC (a partnership of the University of California), Bechtel, BWX Technologies, AECOM, and Battelle Memorial Institute in affiliation with the Texas A&M University System. In 2012, the laboratory had the synthetic chemical element livermorium (element 116) named after it. Overview LLNL is self-described as a "premier research and development institution for sci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cadmium
Cadmium is a chemical element with the symbol Cd and atomic number 48. This soft, silvery-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Like zinc, it demonstrates oxidation state +2 in most of its compounds, and like mercury, it has a lower melting point than the transition metals in groups 3 through 11. Cadmium and its congeners in group 12 are often not considered transition metals, in that they do not have partly filled ''d'' or ''f'' electron shells in the elemental or common oxidation states. The average concentration of cadmium in Earth's crust is between 0.1 and 0.5 parts per million (ppm). It was discovered in 1817 simultaneously by Stromeyer and Hermann, both in Germany, as an impurity in zinc carbonate. Cadmium occurs as a minor component in most zinc ores and is a byproduct of zinc production. Cadmium was used for a long time as a corrosion-resistant plating on steel, and cadmium compounds are used as red, orang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boron
Boron is a chemical element with the symbol B and atomic number 5. In its crystalline form it is a brittle, dark, lustrous metalloid; in its amorphous form it is a brown powder. As the lightest element of the ''boron group'' it has three valence electrons for forming covalent bonds, resulting in many compounds such as boric acid, the mineral borax, sodium borate, and the ultra-hard crystals of boron carbide and boron nitride. Boron is synthesized entirely by cosmic ray spallation and supernovae and not by stellar nucleosynthesis, so it is a low-abundance element in the Solar System and in the Crust (geology), Earth's crust. It constitutes about 0.001 percent by weight of Earth's crust. It is concentrated on Earth by the water-solubility of its more common naturally occurring compounds, the borate minerals. These are mined industrially as evaporites, such as borax and kernite. The largest known deposits are in Turkey, the largest producer of boron minerals. Elemental b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corrosion
Corrosion is a natural process that converts a refined metal into a more chemically stable oxide. It is the gradual deterioration of materials (usually a metal) by chemical or electrochemical reaction with their environment. Corrosion engineering is the field dedicated to controlling and preventing corrosion. In the most common use of the word, this means electrochemical oxidation of metal in reaction with an oxidant such as oxygen, hydrogen or hydroxide. Rusting, the formation of iron oxides, is a well-known example of electrochemical corrosion. This type of damage typically produces oxide(s) or salt(s) of the original metal and results in a distinctive orange colouration. Corrosion can also occur in materials other than metals, such as ceramics or polymers, although in this context, the term "degradation" is more common. Corrosion degrades the useful properties of materials and structures including strength, appearance and permeability to liquids and gases. Many structural ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reliability (engineering)
Reliability engineering is a sub-discipline of systems engineering that emphasizes the ability of equipment to function without failure. Reliability describes the ability of a system or component to function under stated conditions for a specified period of time. Reliability is closely related to availability, which is typically described as the ability of a component or system to function at a specified moment or interval of time. The reliability function is theoretically defined as the probability of success at time t, which is denoted R(t). This probability is estimated from detailed (physics of failure) analysis, previous data sets or through reliability testing and reliability modelling. Availability, testability, maintainability and maintenance are often defined as a part of "reliability engineering" in reliability programs. Reliability often plays the key role in the cost-effectiveness of systems. Reliability engineering deals with the prediction, prevention and manageme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johnston Island
Johnston Atoll is an unincorporated territory of the United States, currently administered by the United States Fish and Wildlife Service (USFWS). Johnston Atoll is a National Wildlife Refuge and part of the Pacific Remote Islands Marine National Monument. It is closed to public entry, and limited access for management needs is only granted by Letter of Authorization from the United States Air Force and a Special Use Permit from the U.S. Fish and Wildlife Service. For nearly 70 years, the isolated atoll was under the control of the U.S. military. During that time, it was variously used as a naval refueling depot, an airbase, a testing site for nuclear and biological weapons, a secret missile base, and a site for the storage and disposal of chemical weapons and Agent Orange. Those activities left the area environmentally contaminated, and monitoring continues. The island is home to thriving communities of nesting seabirds and has significant marine biodiversity. USFWS teams c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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