Nuclear weapon design

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plasma which is mostly transparent to X-rays, and the radiation is absorbed in the outermost layers of the pusher/tamper surrounding the secondary, which ablates and applies a massive force (much like an inside out rocket engine) causing the fusion fuel capsule to implode much like the pit of the primary. As the secondary implodes a fissile "spark plug" at its center ignites and provides neutrons and heat which enable the lithium deuteride fusion fuel to produce tritium and ignite as well. The fission and fusion chain reactions exchange neutrons with each other and boost the efficiency of both reactions. The greater implosive force, enhanced efficiency of the fissile "spark plug" due to boosting via fusion neutrons, and the fusion explosion itself provide significantly greater explosive yield from the secondary despite often not being much larger than the primary.

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quickly in collisions with charged nuclei or electrons. The dominant contribution of fission neutrons to the bomb's power is the initiation of subsequent fissions. Over half of the neutrons escape the bomb core, but the rest strike U nuclei causing them to fission in an exponentially growing chain reaction (1, 2, 4, 8, 16, etc.). Starting from one atom, the number of fissions can theoretically double a hundred times in a microsecond, which could consume all uranium or plutonium up to hundreds of tons by the hundredth link in the chain. Typically in a modern weapon, the weapon's pit contains 3.5 to 4.5 kilograms (7.7 to 9.9 lb) of plutonium and at detonation produces approximately 5 to 10 kilotonnes of TNT (21 to 42 TJ) yield, representing the fissioning of approximately 0.5 kilograms (1.1 lb) of plutonium.

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carried eastward by wind. The resulting trench was around 700 m long and 340 m wide, with an unimpressive depth of just 10–15m. Despite their "clean" nature, the area still exhibits a noticeably higher (albeit mostly harmless) concentration of fission products, the intense neutron bombardment of the soil, the device itself and the support structures also activated their stable elements to create a significant amount of man-made radioactive elements like Co. The overall danger posed by the concentration of radioactive elements present at the site created by these three devices is still negligible, but a larger scale project as was envisioned would have had significant consequences both from the fallout of radioactive plume and the radioactive elements created by the neutron bombardment.

2792:(TTBT), which limited underground explosions to 150 kilotons or less, warheads like the half-megaton W88 had to be tested at less than full yield. Since the primary must be detonated at full yield in order to generate data about the implosion of the secondary, the reduction in yield had to come from the secondary. Replacing much of the lithium-6 deuteride fusion fuel with lithium-7 hydride limited the tritium available for fusion, and thus the overall yield, without changing the dynamics of the implosion. The functioning of the device could be evaluated using light pipes, other sensing devices, and analysis of trapped weapon debris. The full yield of the stockpiled weapon could be calculated by extrapolation. 20: 5208: 1128: 1048:. If spontaneous fission were to occur when the supercritical mass was only partially assembled, the chain reaction would begin prematurely. Neutron losses through the void between the two subcritical masses (gun assembly) or the voids between not-fully-compressed fuel nuclei (implosion assembly) would sap the bomb of the number of fission events needed to attain the full design yield. Additionally, heat resulting from the fissions that do occur would work against the continued assembly of the supercritical mass, from thermal expansion of the fuel. This failure is called 1096:. The resulting small-scale fusion produces neutrons at a protected location outside the physics package, from which they penetrate the pit. This method allows better timing of the first fission events in the chain reaction, which optimally should occur at the point of maximum compression/supercriticality. Timing of the neutron injection is a more important parameter than the number of neutrons injected: the first generations of the chain reaction are vastly more effective due to the exponential function by which neutron multiplication evolves. 2704:+ n reaction is exothermic, producing 5 MeV per event. The spark plug has not yet been compressed and thus remains subcritical, so no significant fission or fusion takes place as a result. If enough neutrons arrive before implosion of the secondary is complete, though, the crucial temperature differential between the outer and inner parts of the secondary can be degraded, potentially causing the secondary to fail to ignite. The first Livermore-designed thermonuclear weapon, the Morgenstern device, failed in this manner when it was tested as 3077:-coated wire inserted into the weapon's hollow pit at manufacture. The warhead was armed by withdrawing the wire onto a spool driven by an electric motor. Once withdrawn, the wire could not be re-inserted. The wire had a tendency to become brittle during storage, and break or get stuck during arming, preventing complete removal and rendering the warhead a dud. It was estimated that 50–75% of warheads would fail. This required a complete rebuild of all W47 primaries. The oil used for lubricating the wire also promoted corrosion of the pit. 1784:

No material is better suited for both of these jobs than ordinary, cheap uranium-238, which also happens to undergo fission when struck by the neutrons produced by D-T fusion. This casing, called the pusher, thus has three jobs: to keep the secondary cool; to hold it, inertially, in a highly compressed state; and, finally, to serve as the chief energy source for the entire bomb. The consumable pusher makes the bomb more a uranium fission bomb than a hydrogen fusion bomb. Insiders never used the term "hydrogen bomb".

1621: 543:(MeV); i.e., 74 TJ/kg. Only 7% of this is gamma radiation and kinetic energy of fission neutrons. The remaining 93% is kinetic energy (or energy of motion) of the charged fission fragments, flying away from each other mutually repelled by the positive charge of their protons (38 for strontium, 54 for xenon). This initial kinetic energy is 67 TJ/kg, imparting an initial speed of about 12,000 kilometers per second (i.e. 1.2 cm per nanosecond). The charged fragments' high electric charge causes many inelastic 4837:, May 17, 2000. Goad began thermonuclear weapon design work at Los Alamos in 1950. In his Declaration, he mentions "basic scientific problems of computability which cannot be solved by more computing power alone. These are typified by the problem of long range predictions of weather and climate, and extend to predictions of nuclear weapons behavior. This accounts for the fact that, after the enormous investment of effort over many years, weapons codes can still not be relied on for significantly new designs." 116: 1408: 1537: 1178: 1108:

which can be arbitrarily long without ever reaching criticality. Another method of reducing criticality risk is to incorporate material with a large cross-section for neutron capture, such as boron (specifically B comprising 20% of natural boron). Naturally this neutron absorber must be removed before the weapon is detonated. This is easy for a gun-assembled bomb: the projectile mass simply shoves the absorber out of the void between the two subcritical masses by the force of its motion.

742: 2763: 3696:, 1976, "This book is about ... the development of the H-bomb, or the superbomb as it was then called." p. ix, and "The rapid and successful development of the superbomb (or super as it came to be called) ..." p. 5. From National Public Radio Talk of the Nation, November 8, 2005, Siegfried Hecker of Los Alamos, "the hydrogen bomb – that is, a two-stage thermonuclear device, as we referred to it – is indeed the principal part of the US arsenal, as it is of the Russian arsenal." 1893:

test. The 1952 U.S. Ivy Mike test used cryogenically cooled liquid deuterium as the fusion fuel in the secondary, and employed the D-D fusion reaction. However, the first Soviet test to use a radiation-imploded secondary, the essential feature of a true H-bomb, was on November 23, 1955, three years after Ivy Mike. In fact, real work on the implosion scheme in the Soviet Union only commenced in the very early part of 1953, several months after the successful testing of Sloika.

397:(U), the uranium nucleus splits into two smaller nuclei called fission fragments, plus more neutrons (for U three about as often as two; an average of just under 2.5 per fission). The fission chain reaction in a supercritical mass of fuel can be self-sustaining because it produces enough surplus neutrons to offset losses of neutrons escaping the supercritical assembly. Most of these have the speed (kinetic energy) required to cause new fissions in neighboring uranium nuclei. 2313:

intense neutron radiation to increase its overall explosive yield. In terms of yield, ERWs typically produce about one-tenth that of a fission-type atomic weapon. Even with their significantly lower explosive power, ERWs are still capable of much greater destruction than any conventional bomb. Meanwhile, relative to other nuclear weapons, damage is more focused on biological material than on material infrastructure (though extreme blast and heat effects are not eliminated).

3013: 2806: 769:, or hydrogen-3. Tritium is employed in two ways. First, pure tritium gas is produced for placement inside the cores of boosted fission devices in order to increase their energy yields. This is especially so for the fission primaries of thermonuclear weapons. The second way is indirect, and takes advantage of the fact that the neutrons emitted by a supercritical fission "spark plug" in the secondary assembly of a two-stage thermonuclear bomb will produce tritium 2686: 7107: 3198:(W.H. Freeman, 1976), it was not a true hydrogen bomb (it was a boosted fission weapon of the Sloika/Alarm Clock type, not a two-stage thermonuclear). Soviet dates for the essential elements of warhead miniaturization – boosted, hollow-pit, two-point, air lens primaries – are not available in the open literature, but the larger size of Soviet ballistic missiles is often explained as evidence of an initial Soviet difficulty in miniaturizing warheads. 2321:

heat, surviving (relatively) very close to a detonation. Given the Soviets' vast tank forces during the Cold War, this was the perfect weapon to counter them. The neutron radiation could instantly incapacitate a tank crew out to roughly the same distance that the heat and blast would incapacitate an unprotected human (depending on design). The tank chassis would also be rendered highly radioactive, temporarily preventing its re-use by a fresh crew.

1725: 1594: 2886:, was redesigned to make secondaries. Fissile U-235 makes the best spark plugs because its critical mass is larger, especially in the cylindrical shape of early thermonuclear secondaries. Early experiments used the two fissile materials in combination, as composite Pu-Oy pits and spark plugs, but for mass production, it was easier to let the factories specialize: plutonium pits in primaries, uranium spark plugs and pushers in secondaries. 1003: 1454: 942: 4817:, UCRL-LR-124754, June 1995, Ph.D. Dissertation, Massachusetts Institute of Technology, available from National Technical Information Service. This 233-page thesis was written by a weapons-lab outsider for public distribution. The author had access to all the classified information at Livermore that was relevant to her research on warhead design; consequently, she was required to use non-descriptive code words for certain innovations. 1217: 1224: 3217: 7095: 1902: 1375: 7119: 2926: 3092:

that transfers or releases energy, energy can't be transferred into other weapon systems, potentially starting a nuclear detonation. Hard links are usually critical weapon components that have been hardened to survive extreme environments, while weak links can be both components deliberately inserted into the system to act as a weak link and critical nuclear components that can fail predictably.

1156:, the 64 kg (141 lb) was more than twice critical mass. Before the detonation, the uranium-235 was formed into two sub-critical pieces, one of which was later fired down a gun barrel to join the other, starting the nuclear explosion. Analysis shows that less than 2% of the uranium mass underwent fission; the remainder, representing most of the entire wartime output of the 1041:

weapon is in the vicinity of the target. This is not difficult to arrange as it takes but a second or two in a typical-size fuel mass for this to occur. (Still, many such bombs meant for delivery by air (gravity bomb, artillery shell or rocket) use injected neutrons to gain finer control over the exact detonation altitude, important for the destructive effectiveness of airbursts.)

3464:, pp. 12–13. When 454 g (one pound) of U undergoes complete fission, the yield is 8 kilotons. The 13 to 16-kiloton yield of the Little Boy bomb was therefore produced by the fission of no more than 2 pounds (910 g) of U, out of the 141 pounds (64,000 g) in the pit. Thus, the remaining 139 pounds (63 kg), 98.5% of the total, contributed nothing to the energy yield. 1849: 1419:, is placed in the explosive just inside the detonators. When the detonators are fired, the initial detonation is trapped between the shaper and the end of the cylinder, causing it to travel out to the edges of the shaper where it is diffracted around the edges into the main mass of explosive. This causes the detonation to form into a ring that proceeds inward from the shaper. 1819:

would replace "toxic, brittle material" and "expensive 'special' material" in the interstage. This statement suggests the interstage may contain beryllium to moderate the flux of neutrons from the primary, and perhaps something to absorb and re-radiate the x-rays in a particular manner. There is also some speculation that this interstage material, which may be code-named

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right end (1) sent information about the detonation of the primary. Two in the middle (2) marked the time when X-rays from the primary reached the radiation channel around the secondary. The last two pipes (3) noted the time radiation reached the far end of the radiation channel, the difference between (2) and (3) being the radiation transit time for the channel.

1059:. If the fuel mass contains impurity elements of low atomic number (Z), these charged alphas can penetrate the coulomb barrier of these impurity nuclei and undergo a reaction that yields a free neutron. The rate of alpha emission of fissile nuclei is one to two million times that of spontaneous fission, so weapon engineers are careful to use fuel of high purity. 582:, converting neutrons into protons by throwing off beta particles (electrons), neutrinos and gamma rays. Their half-lives range from milliseconds to about 200,000 years. Many decay into isotopes that are themselves radioactive, so from 1 to 6 (average 3) decays may be required to reach stability. In reactors, the radioactive products are the nuclear waste in 2267:

the US and Soviet Union investigated (and in the case of the Soviets, tested) "very high yield" (e.g. +50-100 megaton) weapons designs in the 1950s and early 1960s, these appear to represent the upper-limit of Cold War weapon yields pursued seriously. Cold War warhead development trends from the mid-1960s onward, and especially after the

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daughter neutrons can no longer find new fuel nuclei to hit before escaping the less-dense fuel mass. Each following fission event in the chain approximately doubles the neutron population (net, after losses due to some neutrons escaping the fuel mass, and others that collide with any non-fuel impurity nuclei present).

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any extra neutrons will be multiplied by the chain reaction, so even tiny quantities introduced early can have a large effect on the outcome. For this reason, even the relatively low compression pressures and times (in fusion terms) found in the center of a hollow pit warhead are enough to create the desired effect.

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clear. In many case (as with antimatter) the underlying technology is presently thought to be very far from being viable, and if it was viable would be a powerful weapon in and of itself, outside of a nuclear weapons context, and without providing any significant advantages above existing nuclear weapons designs

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hemisphere away from the first, like toothpaste in a tube. By the time the explosion envelops it, its implosion will be separated both in time and space from the implosion of the first hemisphere. The resulting dumbbell shape, with each end reaching maximum density at a different time, may not become critical.

1052:. The resulting explosion would be called a "fizzle" by bomb engineers and weapon users. Plutonium's high rate of spontaneous fission makes uranium fuel a necessity for gun-assembled bombs, with their much greater insertion time and much greater mass of fuel required (because of the lack of fuel compression). 3189:

The United States and the Soviet Union were the only nations to build large nuclear arsenals with every possible type of nuclear weapon. The U.S. had a four-year head start and was the first to produce fissile material and fission weapons, all in 1945. The only Soviet claim for a design first was the

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It is not clear from the public record how successful the Shrimp light pipes were. The unmanned data bunker was far enough back to remain outside the mile-wide crater, but the 15-megaton blast, two and a half times as powerful as expected, breached the bunker by blowing its 20-ton door off the hinges

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In a nuclear explosion, a large number of discrete events, with various probabilities, aggregate into short-lived, chaotic energy flows inside the device casing. Complex mathematical models are required to approximate the processes, and in the 1950s there were no computers powerful enough to run them

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reported work on a 10,000 megaton weapon code-named SUNDIAL at a meeting of the General Advisory Committee of the Atomic Energy Commission. Much of the information about these efforts remains classified, but the weapons ideas do not appear to have made it beyond theoretical investigations. While both

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were usable and controllable in macroscopic quantities, a reaction between a small amount of antimatter and an equivalent amount of matter could release energy comparable to a small fission weapon, and could in turn be used as the first stage of a very compact thermonuclear weapon. Extremely-powerful

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The Ripple concept, which used ablation to achieve fusion using very little fission, was and still is by far the cleanest design. Unlike previous clean bombs, which were clean simply by replacing fission fuel with inert substance, Ripple was by design clean. Ripple was also extremely efficient; plans

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material in the tamper with another material is essential to producing a "clean" bomb. In such a device, the tamper no longer contributes energy, so for any given weight, a clean bomb will have less yield. The earliest known incidence of a three-stage device being tested, with the third stage, called

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The interstage and the secondary are encased together inside a stainless steel membrane to form the canned subassembly (CSA), an arrangement which has never been depicted in any open-source drawing. The most detailed illustration of an interstage shows a British thermonuclear weapon with a cluster of

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For example, for the Redwing Mohawk test on July 3, 1956, a secondary called the Flute was attached to the Swan primary. The Flute was 15 inches (38 cm) in diameter and 23.4 inches (59 cm) long, about the size of the Swan. But it weighed ten times as much and yielded 24 times as much energy

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thought the secondary would be a canister of deuterium in liquefied or hydride form. The fusion reaction would be D-D, harder to achieve than D-T, but more affordable. A fission bomb at one end would shock-compress and heat the near end, and fusion would propagate through the canister to the far end.

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To avoid a premature chain reaction during handling, the fissile material in the weapon must be kept subcritical. It may consist of one or more components containing less than one uncompressed critical mass each. A thin hollow shell can have more than the bare-sphere critical mass, as can a cylinder,

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events, which occur randomly (it is a quantum mechanical phenomenon). Because the fissile material in a gun-assembled critical mass is not compressed, the design need only ensure the two subcritical masses remain close enough to each other long enough that a U spontaneous fission will occur while the

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The total energy output, 17.6 MeV, is one tenth of that with fission, but the ingredients are only one-fiftieth as massive, so the energy output per unit mass is approximately five times as great. In this fusion reaction, 14 of the 17.6 MeV (80% of the energy released in the reaction) shows up as the

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On August 9, 1945, Fat Man was loaded onto its airplane fully assembled, but later, when levitated pits made a space between the pit and the tamper, it was feasible to use in-flight pit insertion. The bomber would take off with no fissile material in the bomb. Some older implosion-type weapons, such

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The Hanford Site near Richland WA operated Plutonium production nuclear reactors and separations facilities during World War 2 and the Cold War. Nine Plutonium production reactors were built and operated there. The first being the B-Reactor which began operations in September 1944 and the last being

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impurities. So Fat Man, the implosion-type bomb, was given high priority as the only option for plutonium. The Berkeley discussions had generated theoretical estimates of critical mass, but nothing precise. The main wartime job at Los Alamos was the experimental determination of critical mass, which

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All the nuclear weapon design innovations discussed in this article originated from the following three labs in the manner described. Other nuclear weapon design labs in other countries duplicated those design innovations independently, reverse-engineered them from fallout analysis, or acquired them

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In a two-stage thermonuclear weapon the energy from the primary impacts the secondary. An essential energy transfer modulator called the interstage, between the primary and the secondary, protects the secondary's fusion fuel from heating too quickly, which could cause it to explode in a conventional

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Finally, the heat for fusion ignition comes not from the primary but from a second fission bomb called the spark plug, embedded in the heart of the secondary. The implosion of the secondary implodes this spark plug, detonating it and igniting fusion in the material around it, but the spark plug then

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For the secondary to be imploded by the hot, radiation-induced plasma surrounding it, it must remain cool for the first microsecond, i.e., it must be encased in a massive radiation (heat) shield. The shield's massiveness allows it to double as a tamper, adding momentum and duration to the implosion.

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In radiation implosion, the burst of X-ray energy coming from an exploding primary is captured and contained within an opaque-walled radiation channel which surrounds the nuclear energy components of the secondary. The radiation quickly turns the plastic foam that had been filling the channel into a

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experiments this mixture must be held at high temperatures for relatively lengthy times in order to have an efficient reaction. For explosive use, however, the goal is not to produce efficient fusion, but simply provide extra neutrons early in the process. Since a nuclear explosion is supercritical,

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The key to Fat Man's greater efficiency was the inward momentum of the massive U-238 tamper. (The natural uranium tamper did not undergo fission from thermal neutrons, but did contribute perhaps 20% of the total yield from fission by fast neutrons). After the chain reaction started in the plutonium,

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reflector/tamper, the Fat Man's pit was brought close to critical mass by the neutron-reflecting properties of the U-238. During detonation, criticality was achieved by implosion. The plutonium pit was squeezed to increase its density by simultaneous detonation, as with the "Trinity" test detonation

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fired from the barrel of a much larger gun). Such warheads were deployed by the United States until 1992, accounting for a significant fraction of the U in the arsenal, and were some of the first weapons dismantled to comply with treaties limiting warhead numbers. The rationale for this decision was

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The neutrons are supplied by the nuclear reactor in a way similar to production of plutonium Pu from U feedstock: target rods of the Li feedstock are arranged around a uranium-fueled core, and are removed for processing once it has been calculated that most of the lithium nuclei have been transmuted

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Meanwhile, inside the exploding bomb, the free neutrons released by fission carry away about 3% of the initial fission energy. Neutron kinetic energy adds to the blast energy of a bomb, but not as effectively as the energy from charged fragments, since neutrons do not give up their kinetic energy as

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Neither of these effects is likely with implosion weapons since there is normally insufficient fissile material to form a critical mass without the correct detonation of the lenses. However, the earliest implosion weapons had pits so close to criticality that accidental detonation with some nuclear

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In 1957 and 1958, both labs built and tested as many designs as possible, in anticipation that a planned 1958 test ban might become permanent. By the time testing resumed in 1961 the two labs had become duplicates of each other, and design jobs were assigned more on workload considerations than lab

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Neutron weapons were also intended for use in other applications, however. For example, they are effective in anti-nuclear defenses – the neutron flux being capable of neutralising an incoming warhead at a greater range than heat or blast. Nuclear warheads are very resistant to physical damage, but

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A hollow plutonium pit was the original plan for the 1945 Fat Man bomb, but there was not enough time to develop and test the implosion system for it. A simpler solid-pit design was considered more reliable, given the time constraints, but it required a heavy U-238 tamper, a thick aluminium pusher,

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An implosion shock wave might be of such short duration that only part of the pit is compressed at any instant as the wave passes through it. To prevent this, a pusher shell may be needed. The pusher is located between the explosive lens and the tamper. It works by reflecting some of the shock wave

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To start the chain reaction in a supercritical assembly, at least one free neutron must be injected and collide with a fissile fuel nucleus. The neutron joins with the nucleus (technically a fusion event) and destabilizes the nucleus, which explodes into two middleweight nuclear fragments (from the

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The only practical way to capture most of the fusion energy is to trap the neutrons inside a massive bottle of heavy material such as lead, uranium, or plutonium. If the 14 MeV neutron is captured by uranium (of either isotope; 14 MeV is high enough to fission both U and U) or plutonium, the result

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The physics package is the nuclear explosive module inside the bomb casing, missile warhead, or artillery shell, etc., which delivers the weapon to its target. While photographs of weapon casings are common, photographs of the physics package are quite rare, even for the oldest and crudest nuclear

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test. Its 15-megaton explosion was the largest ever by the United States. The silhouette of a man is shown for scale. The device is supported from below, at the ends. The pipes going into the shot cab ceiling, which appear to be supports, are actually diagnostic light pipes. The eight pipes at the

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Commonly misconceived as a weapon designed to kill populations and leave infrastructure intact, these bombs (as mentioned above) are still very capable of leveling buildings over a large radius. The intent of their design was to kill tank crews – tanks giving excellent protection against blast and

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research programs, since the 1970s it has not been considered promising for direct weapons use, but rather as a tool for weapons- and energy-related research that can be used in the absence of full-scale nuclear testing. Whether any nations are aggressively pursuing "4th-generation" weapons is not

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In the boosted design, the fusion fuel in gas form is pumped into the pit during arming. This will fuse into helium and release free neutrons soon after fission begins. The neutrons will start a large number of new chain reactions while the pit is still critical or nearly critical. Once the hollow

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For national powers engaged in a nuclear arms race, this fact of U's ability to fast-fission from thermonuclear neutron bombardment is of central importance. The plenitude and cheapness of both bulk dry fusion fuel (lithium deuteride) and U (a byproduct of uranium enrichment) permit the economical

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Compere, A.L., and Griffith, W.L. 1991. "The U.S. Calutron Program for Uranium Enrichment: History,. Technology, Operations, and Production. Report", ORNL-5928, as cited in John Coster-Mullen, "Atom Bombs: The Top Secret Inside Story of Little Boy and Fat Man", 2003, footnote 28, p. 18. The total

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Modern boosted fission triggers take this evolution towards higher yield to weight, smaller volume, and greater ease of radiation escape to an extreme. Comparable explosive yields are produced by a core consisting of 3.5–4.5 kg of plutonium, 5–6 kg of beryllium reflector, and some 20 kilograms of

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Under the strong link/weak link system, "weak links" are constructed between critical nuclear weapon components (the "hard links"). In the event of an accident the weak links are designed to fail first in a manner that precludes energy transfer between them. Then, if a hard link fails in a manner

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In the last test before the 1958 moratorium the W47 warhead for the Polaris SLBM was found to not be one-point safe, producing an unacceptably high nuclear yield of 200 kg (440 lb) of TNT equivalent (Hardtack II Titania). With the test moratorium in force, there was no way to refine the

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to absorb neutrons. While the chain is in the center of the pit, the pit cannot be compressed into an appropriate shape to fission; when the weapon is to be armed, the chain is removed. Similarly, although a serious fire could detonate the explosives, destroying the pit and spreading plutonium to

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A neutron bomb, technically referred to as an enhanced radiation weapon (ERW), is a type of tactical nuclear weapon designed specifically to release a large portion of its energy as energetic neutron radiation. This contrasts with standard thermonuclear weapons, which are designed to capture this

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Since the 1950s, the United States and Soviet Union investigated the possibility of releasing significant amounts of nuclear fusion energy without the use of a fission primary. Such "pure fusion weapons" were primarily imagined as low-yield, tactical nuclear weapons whose advantage would be their

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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

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There is very little information in the open literature about the mechanism of the interstage. Its first mention in a U.S. government document formally released to the public appears to be a caption in a graphic promoting the Reliable Replacement Warhead Program in 2007. If built, this new design

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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

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The optimal way to store deuterium in a reasonably dense state is to chemically bond it with lithium, as lithium deuteride. But the lithium-6 isotope is also the raw material for tritium production, and an exploding bomb is a nuclear reactor. Radiation implosion will hold everything together long

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of fissile (weapon grade) uranium or plutonium. A supercritical mass is one in which the percentage of fission-produced neutrons captured by other neighboring fissile nuclei is large enough that each fission event, on average, causes more than one follow-on fission event. Neutrons released by the

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Fusion produces neutrons which dissipate energy from the reaction. In weapons, the most important fusion reaction is called the D-T reaction. Using the heat and pressure of fission, hydrogen-2, or deuterium (D), fuses with hydrogen-3, or tritium (T), to form helium-4 (He) plus one neutron (n) and

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Nuclear fission separates or splits heavier atoms to form lighter atoms. Nuclear fusion combines lighter atoms to form heavier atoms. Both reactions generate roughly a million times more energy than comparable chemical reactions, making nuclear bombs a million times more powerful than non-nuclear

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It is not possible to tell on the drawing board how this will play out. Nor is it possible using a dummy pit of U-238 and high-speed x-ray cameras, although such tests are helpful. For final determination, a test needs to be made with real fissile material. Consequently, starting in 1957, a year

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Because primaries tend to be bulky, especially in diameter, plutonium is the fissile material of choice for pits, with beryllium reflectors. It has a smaller critical mass than uranium. The Rocky Flats plant near Boulder, Colorado, was built in 1952 for pit production and consequently became the

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While x-rays would normally travel at the speed of light through a low-density material like the plastic foam channel filler between (2) and (3), the intensity of radiation from the exploding primary creates a relatively opaque radiation front in the channel filler, which acts like a slow-moving

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A neutron bomb is only feasible if the yield is sufficiently high that efficient fusion stage ignition is possible, and if the yield is low enough that the case thickness will not absorb too many neutrons. This means that neutron bombs have a yield range of 1–10 kilotons, with fission proportion

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The idea of a device which has an arbitrarily large number of Teller-Ulam stages, with each driving a larger radiation-driven implosion than the preceding stage, is frequently suggested, but technically disputed. There are "well-known sketches and some reasonable-looking calculations in the open

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test was to demonstrate the feasibility of the project. Three of these "clean" devices of 15 kiloton yield each were placed in separate boreholes spaced about 165 m apart at depths of 127 m. They were simultaneously detonated on March 23, 1971, catapulting radioactive plume into the air that was

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Because the Soviet Sloika test used dry lithium-6 deuteride eight months before the first U.S. test to use it (Castle Bravo, March 1, 1954), it was sometimes claimed that the USSR won the H-bomb race, even though the United States tested and developed the first hydrogen bomb: the Ivy Mike H-bomb

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After the war, interest in the hollow pit design was revived. Its obvious advantage is that a hollow shell of plutonium, shock-deformed and driven inward toward its empty center, would carry momentum into its violent assembly as a solid sphere. It would be self-tamping, requiring a smaller U-238

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holding the mutually-repulsive protons together), plus two or three free neutrons. These race away and collide with neighboring fuel nuclei. This process repeats over and over until the fuel assembly goes subcritical (from thermal expansion), after which the chain reaction shuts down because the

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In a two-point system, if one detonator fires, one entire hemisphere of the pit will implode as designed. The high-explosive charge surrounding the other hemisphere will explode progressively, from the equator toward the opposite pole. Ideally, this will pinch the equator and squeeze the second

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Shifting gears, Livermore settled for taking ideas Los Alamos had shelved and developing them for the Army and Navy. This led Livermore to specialize in small-diameter tactical weapons, particularly ones using two-point implosion systems, such as the Swan. Small-diameter tactical weapons became

1111:

The use of plutonium affects weapon design due to its high rate of alpha emission. This results in Pu metal spontaneously producing significant heat; a 5 kilogram mass-produces 9.68 watts of thermal power. Such a piece would feel warm to the touch, which is no problem if that heat is dissipated

1099:

The critical mass of an uncompressed sphere of bare metal is 50 kg (110 lb) for uranium-235 and 16 kg (35 lb) for delta-phase plutonium-239. In practical applications, the amount of material required for criticality is modified by shape, purity, density, and the proximity to

1062:

Fission weapons used in the vicinity of other nuclear explosions must be protected from the intrusion of free neutrons from outside. Such shielding material will almost always be penetrated, however, if the outside neutron flux is intense enough. When a weapon misfires or fizzles because of the

756:

For weapon use, fission is necessary to start fusion, helps to sustain fusion, and captures and multiplies the energy carried by the fusion neutrons. In the case of a neutron bomb (see below), the last-mentioned factor does not apply, since the objective is to facilitate the escape of neutrons,

1547:

The next step in miniaturization was to speed up the fissioning of the pit to reduce the minimum inertial confinement time. This would allow the efficient fission of the fuel with less mass in the form of tamper or the fuel itself. The key to achieving faster fission would be to introduce more

378:

In some ways, fission and fusion are opposite and complementary reactions, but the particulars are unique for each. To understand how nuclear weapons are designed, it is useful to know the important similarities and differences between fission and fusion. The following explanation uses rounded

2734:

The most interesting data from Castle Bravo came from radio-chemical analysis of weapon debris in fallout. Because of a shortage of enriched lithium-6, 60% of the lithium in the Shrimp secondary was ordinary lithium-7, which doesn't breed tritium as easily as lithium-6 does. But it does breed

1749:

The primary's reaction is over and it has expanded. The surface of the pusher for the secondary is now so hot that it is also ablating or expanding away, pushing the rest of the secondary (tamper, fusion fuel, and fissile spark plug) inward. The spark plug starts to fission. Not depicted: the

1422:

Due to the lack of a tamper or lenses to shape the progression, the detonation does not reach the pit in a spherical shape. To produce the desired spherical implosion, the fissile material itself is shaped to produce the same effect. Due to the physics of the shock wave propagation within the

82:

Pure fission weapons 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

1398:

The Pu-239 pit of Fat Man was only 9.1 centimetres (3.6 in) in diameter, the size of a softball. The bulk of Fat Man's girth was the implosion mechanism, namely concentric layers of U-238, aluminium, and high explosives. The key to reducing that girth was the two-point implosion design.

604:

Uranium's most common isotope, U, is fissionable but not fissile, meaning that it cannot sustain a chain reaction because its daughter fission neutrons are not (on average) energetic enough to cause follow-on U fissions. However, the neutrons released by fusion of the heavy hydrogen isotopes

3001:. The balls were emptied into the pit: this prevented detonation by increasing the density of the hollow pit, thereby preventing symmetrical implosion in the event of an accident. This design was used in the Green Grass weapon, also known as the Interim Megaton Weapon, which was used in the 2316:

ERWs are more accurately described as suppressed yield weapons. When the yield of a nuclear weapon is less than one kiloton, its lethal radius from blast, 700 m (2,300 ft), is less than that from its neutron radiation. However, the blast is more than potent enough to destroy most

1677:

Pure fission or fusion-boosted fission weapons can be made to yield hundreds of kilotons, at great expense in fissile material and tritium, but by far the most efficient way to increase nuclear weapon yield beyond ten or so kilotons is to add a second independent stage, called a secondary.

1439:

artillery shell, the smallest nuclear weapon ever built or deployed. All such low-yield battlefield weapons, whether gun-type U-235 designs or linear implosion Pu-239 designs, pay a high price in fissile material in order to achieve diameters between six and ten inches (15 and 25 cm).

1768:

A spherical secondary can achieve higher implosion densities than a cylindrical secondary, because spherical implosion pushes in from all directions toward the same spot. However, in warheads yielding more than one megaton, the diameter of a spherical secondary would be too large for most

1427:, that is, roughly egg shaped. The shock wave first reaches the pit at its tips, driving them inward and causing the mass to become spherical. The shock may also change plutonium from delta to alpha phase, increasing its density by 23%, but without the inward momentum of a true implosion. 1019:

first fission events induce subsequent fission events at an exponentially accelerating rate. Each follow-on fissioning continues a sequence of these reactions that works its way throughout the supercritical mass of fuel nuclei. This process is conceived and described colloquially as the

530: 1163:

The inefficiency was caused by the speed with which the uncompressed fissioning uranium expanded and became sub-critical by virtue of decreased density. Despite its inefficiency, this design, because of its shape, was adapted for use in small-diameter, cylindrical artillery shells (a

1831:

items between its primary and a cylindrical secondary. They are labeled "end-cap and neutron focus lens", "reflector/neutron gun carriage", and "reflector wrap". The origin of the drawing, posted on the internet by Greenpeace, is uncertain, and there is no accompanying explanation.

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enough to permit the complete conversion of lithium-6 into tritium, while the bomb explodes. So the bonding agent for deuterium permits use of the D-T fusion reaction without any pre-manufactured tritium being stored in the secondary. The tritium production constraint disappears.

1764:

Equally important, the active ingredients in the Flute probably cost no more than those in the Swan. Most of the fission came from cheap U-238, and the tritium was manufactured in place during the explosion. Only the spark plug at the axis of the secondary needed to be fissile.

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Another benefit of boosting, in addition to making weapons smaller, lighter, and with less fissile material for a given yield, is that it renders weapons immune to predetonation. It was discovered in the mid-1950s that plutonium pits would be particularly susceptible to partial

1112:

promptly and not allowed to build up the temperature. But this is a problem inside a nuclear bomb. For this reason bombs using Pu fuel use aluminum parts to wick away the excess heat, and this complicates bomb design because Al plays no active role in the explosion processes.

2912:

which converted U-238 into Pu-239 for pits, and converted lithium-6 (produced at Y-12) into tritium for booster gas. Since its reactors were moderated with heavy water, deuterium oxide, it also made deuterium for booster gas and for Y-12 to use in making lithium-6 deuteride.

78:, which illuminates and implodes the second stage filled with a large quantity of fusion fuel. This sets in motion a sequence of events which results in a thermonuclear, or fusion, burn. This process affords potential yields up to hundreds of times those of fission weapons. 2673:

An important tool for test analysis was the diagnostic light pipe. A probe inside a test device could transmit information by heating a plate of metal to incandescence, an event that could be recorded by instruments located at the far end of a long, very straight pipe.

1955:. Shot Androscoggin shot featured a proof-of-concept Ripple design, resulting in a 63-kiloton fizzle (significantly lower than the predicted 15 megatons). It was repeated in shot Housatonic, which featured a 9.96 megaton explosion that was reportedly >99.9% fusion. 2715:

These timing effects, and any problems they cause, are measured by light-pipe data. The mathematical simulations which they calibrate are called radiation flow hydrodynamics codes, or channel codes. They are used to predict the effect of future design modifications.

1262:

and a remote site 14.3 km (8.9 mi) east of it in Bayo Canyon, proved the practicality of the implosion design for a fission device, with the February 1945 tests positively determining its usability for the final Trinity/Fat Man plutonium implosion design.

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The idea of "4th-generation" nuclear weapons has been proposed as a possible successor to the examples of weapons designs listed above. These methods tend to revolve around using non-nuclear primaries to set off further fission or fusion reactions. For example, if

2608:

Warhead designs after 1960 took on the character of model changes, with every new missile getting a new warhead for marketing reasons. The chief substantive change involved packing more fissile uranium-235 into the secondary, as it became available with continued

3179:

test. Because explosions are spherical in shape and targets are spread out on the relatively flat surface of the earth, numerous smaller weapons cause more destruction. From page 35: "... five five-megaton weapons would demolish a greater area than a single

73:

are 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

2935:

warhead's steel ball safety device, shown left, filled (safe) and right, empty (live). The steel balls were emptied into a hopper underneath the aircraft before flight, and could be re-inserted using a funnel by rotating the bomb on its trolley and raising the

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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.

749:

kinetic energy of the neutron, which, having no electric charge and being almost as massive as the hydrogen nuclei that created it, can escape the scene without leaving its energy behind to help sustain the reaction – or to generate x-rays for blast and fire.

1035:

For the gun assembly method (see below) of supercritical mass formation, the fuel itself can be relied upon to initiate the chain reaction. This is because even the best weapon-grade uranium contains a significant number of U nuclei. These are susceptible to

2738:

Fallout analysis revealed to designers that, with the (n, 2n) reaction, the Shrimp secondary effectively had two and half times as much lithium-6 as expected. The tritium, the fusion yield, the neutrons, and the fission yield were all increased accordingly.

601:(HEU), "oralloy" meaning "Oak Ridge alloy", or "25" (a combination of the last digit of the atomic number of uranium-235, which is 92, and the last digit of its mass number, which is 235); and Pu, also known as plutonium-239, or "49" (from "94" and "239"). 2018:

First and second generation nuclear weapons release energy as omnidirectional blasts. Third generation nuclear weapons are experimental special effect warheads and devices that can release energy in a directed manner, some of which were tested during the

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In the ensuing fifty years, no one has come up with a more efficient way to build a thermonuclear 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

892: 4405:

Ramzaev, V; Repin, V; Medvedev, A; Khramtsov, E; Timofeeva, M; Yakovlev, V (2012). "Radiological investigations at the 'Taiga' nuclear explosion site, part II: man-made γ-ray emitting radionuclides in the ground and the resultant kerma rate in air".

1839:

While every nuclear weapon design falls into one of the above categories, specific designs have occasionally become the subject of news accounts and public discussion, often with incorrect descriptions about how they work and what they do. Examples:

2512:, Little Boy, Fat Man, and an unused spare Fat Man. After the war, those who could, including Oppenheimer, returned to university teaching positions. Those who remained worked on levitated and hollow pits and conducted weapon effects tests such as 3118:

device designed to prevent unauthorised use of nuclear weapons. Early PALs were simple electromechanical switches and have evolved into complex arming systems that include integrated yield control options, lockout devices and anti-tamper devices.

1769:

applications. A cylindrical secondary is necessary in such cases. The small, cone-shaped re-entry vehicles in multiple-warhead ballistic missiles after 1970 tended to have warheads with spherical secondaries, and yields of a few hundred kilotons.

2700:. While the secondary is being compressed via radiation-induced ablation, neutrons from the primary catch up with the x-rays, penetrate into the secondary, and start breeding tritium via the third reaction noted in the first section above. This 1386:

The first improvement on the Fat Man design was to put an air space between the tamper and the pit to create a hammer-on-nail impact. The pit, supported on a hollow cone inside the tamper cavity, was said to be "levitated". The three tests of

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primaries for small-diameter secondaries. Around 1960, when the superpower arms race became a ballistic missile race, Livermore warheads were more useful than the large, heavy Los Alamos warheads. Los Alamos warheads were used on the first

2658:

It was much more difficult to understand how it worked or why it failed. Designers gathered as much data as possible during the explosion, before the device destroyed itself, and used the data to calibrate their models, often by inserting

400:

The uranium-235 nucleus can split in many ways, provided the atomic numbers add up to 92 and the mass numbers add up to 236 (uranium-235 plus the neutron that caused the split). The following equation shows one possible split, namely into

3691:

Until a reliable design was worked out in the early 1950s, the hydrogen bomb (public name) was called the superbomb by insiders. After that, insiders used a more descriptive name: two-stage thermonuclear. Two examples. From Herb York,

1627:

After the success of Swan, 11 or 12 inches (28 or 30 cm) seemed to become the standard diameter of boosted single-stage devices tested during the 1950s. Length was usually twice the diameter, but one such device, which became the

3041:

While the firing of one detonator out of many will not cause a hollow pit to go critical, especially a low-mass hollow pit that requires boosting, the introduction of two-point implosion systems made that possibility a real concern.

2945:

It is inherently dangerous to have a weapon containing a quantity and shape of fissile material which can form a critical mass through a relatively simple accident. Because of this danger, the propellant in Little Boy (four bags of

1414:

In the two-point linear implosion, the nuclear fuel is cast into a solid shape and placed within the center of a cylinder of high explosive. Detonators are placed at either end of the explosive cylinder, and a plate-like insert, or

2394:

varying from 50% at 1-kiloton to 25% at 10-kilotons (all of which comes from the primary stage). The neutron output per kiloton is then 10–15 times greater than for a pure fission implosion weapon or for a strategic warhead like a

1320:, which causes it to take up its delta phase over a wide temperature range. When cooling from molten it then has only a single phase change, from epsilon to delta, instead of the four changes it would otherwise pass through. Other 1083:

separated by a thin barrier. Implosion of the pit crushes the neutron generator, mixing the two metals, thereby allowing alpha particles from the polonium to interact with beryllium to produce free neutrons. In modern weapons, the

3053:

Out of 25 one-point safety tests conducted in 1957 and 1958, seven had zero or slight nuclear yield (success), three had high yields of 300 t to 500 t (severe failure), and the rest had unacceptable yields between those extremes.

2001:

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

927:

Of the four basic types of nuclear weapon, the first, pure fission, uses the first of the three nuclear reactions above. The second, fusion-boosted fission, uses the first two. The third, two-stage thermonuclear, uses all three.

613:

will fission U. This U fission reaction in the outer jacket of the secondary assembly of a two-stage thermonuclear bomb produces by far the greatest fraction of the bomb's energy yield, as well as most of its radioactive debris.

2527:

radiation implosion breakthrough of 1951, the technical implications and possibilities were fully explored, but ideas not directly relevant to making the largest possible bombs for long-range Air Force bombers were shelved.

1267:

it continued until the explosion reversed the momentum of the implosion and expanded enough to stop the chain reaction. By holding everything together for a few hundred nanoseconds more, the tamper increased the efficiency.

2921:

Because even low-yield nuclear warheads have astounding destructive power, weapon designers have always recognised the need to incorporate mechanisms and associated procedures intended to prevent accidental detonation.

2965:, even without the weapon being physically damaged. Similarly, a fire caused by an aircraft crashing could easily ignite the propellant, with catastrophic results. Gun-type weapons have always been inherently unsafe. 1864:

The U.S. name, Alarm Clock, came from Teller: he called it that because it might "wake up the world" to the possibility of the potential of the Super. The Russian name for the same design was more descriptive: Sloika

1070:

For the implosion-assembled design, once the critical mass is assembled to maximum density, a burst of neutrons must be supplied to start the chain reaction. Early weapons used a modulated neutron generator codenamed

2531:

Because of Oppenheimer's initial position in the H-bomb debate, in opposition to large thermonuclear weapons, and the assumption that he still had influence over Los Alamos despite his departure, political allies of

4716: 419: 2748:, sailed home with enough fallout on her decks to allow scientists in Japan and elsewhere to determine, and announce, that most of the fallout had come from the fission of U-238 by fusion-produced 14 MeV neutrons. 1192:(Nagasaki) bomb, nearly identical plutonium fission through implosion designs were used. The Fat Man device specifically used 6.2 kg (14 lb), about 350 ml or 12 US fl oz in volume, of 1394:

It was immediately clear that implosion was the best design for a fission weapon. Its only drawback seemed to be its diameter. Fat Man was 1.5 metres (5 ft) wide vs 61 centimetres (2 ft) for Little Boy.

4774:

William J. Broad, "The Hidden Travels of The Bomb: Atomic insiders say the weapon was invented only once, and its secrets were spread around the globe by spies, scientists and the covert acts of nuclear states",

3061:, which generated unacceptably high yields in one-point testing. To prevent an accidental detonation, Livermore decided to use mechanical safing on the W47. The wire safety scheme described below was the result. 2317:

structures, which are less resistant to blast effects than even unprotected human beings. Blast pressures of upwards of 20 PSI are survivable, whereas most buildings will collapse with a pressure of only 5 PSI.

2146:, the cobalt bomb is a hydrogen bomb with a jacket of cobalt. The neutron-activated cobalt would have maximized the environmental damage from radioactive fallout. These bombs were popularized in the 1964 film 1582:

Since the compressed pit does not need to be held together as long, the massive U-238 tamper can be replaced by a light-weight beryllium shell (to reflect escaping neutrons back into the pit). The diameter is

2227:

project, produced a small amount of fission products and therefore a comparatively large amount of case material activated products are responsible for most of the residual activity at the site today, namely

1689:

The entire fusion fuel canister would need to be enveloped by fission energy, to both compress and heat it, as with the booster charge in a boosted primary. The design breakthrough came in January 1951, when

3653:

he was going to use first hydrodynamics and just the shockwaves and then neutron heating, which would have been a disaster. It would have blown it up before it got going. It was Teller who came up with the

1430:

The lack of compression makes such designs inefficient, but the simplicity and small diameter make it suitable for use in artillery shells and atomic demolition munitions – ADMs – also known as backpack or

563:

between nuclei in the compressed fuel assembly (for the implosion design), this takes about a millionth of a second (a microsecond), by which time the core and tamper of the bomb have expanded to a ball of

4155: 2440:

By the time he moved his operation to the new secret town of Los Alamos, New Mexico, in the spring of 1943, the accumulated wisdom on nuclear weapon design consisted of five lectures by Berkeley professor

1938:, when used as the tamper material in the secondary and subsequent stages in the Teller-Ulam design, can far exceed the energy released by fusion, as was the case in the Castle Bravo test. Replacing the 3095:

An example of a weak link would be an electrical connector that contains electrical wires made from a low melting point alloy. During a fire, those wires would melt, breaking any electrical connection.

1651:

systems because a first strike attack might make retaliatory weapons useless. Boosting reduces the amount of plutonium needed in a weapon to below the quantity which would be vulnerable to this effect.

4180: 64:

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.

5293:

or NPIHP is a global network of individuals and institutions engaged in the study of international nuclear history through archival documents, oral history interviews and other empirical sources.

4686:"A new use for nuclear weapons: hunting rogue asteroids A persistent campaign by weapons designers to develop a nuclear defense against extraterrestrial rocks slowly wins government support 2013" 4362:

Ramzaev, V; Repin, V; Medvedev, A; Khramtsov, E; Timofeeva, M; Yakovlev, V (2011). "Radiological investigations at the 'Taiga' nuclear explosion site: Site description and in situ measurements".

1993:

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

2692:

From the shot cab, the pipes turned horizontally and traveled 7,500 ft (2.3 km) along a causeway built on the Bikini reef to a remote-controlled data collection bunker on Namu Island.

2250:

was responsible for about half of the gamma dose at the test site. That dose is too small to cause deleterious effects, and normal green vegetation exists all around the lake that was formed.

5091: 1144:, the Hiroshima bomb, used 64 kg (141 lb) of uranium with an average enrichment of around 80%, or 51 kg (112 lb) of uranium-235, just about the bare-metal critical mass 4466: 2774:

on November 4, 1962. During the next three decades, until September 23, 1992, the United States conducted an average of 2.4 underground nuclear explosions per month, all but a few at the

2770:

The global alarm over radioactive fallout, which began with the Castle Bravo event, eventually drove nuclear testing literally underground. The last U.S. above-ground test took place at

2742:

As noted above, Bravo's fallout analysis also told the outside world, for the first time, that thermonuclear bombs are more fission devices than fusion devices. A Japanese fishing boat,

1775:

In engineering terms, radiation implosion allows for the exploitation of several known features of nuclear bomb materials which heretofore had eluded practical application. For example:

5272:, Department of Energy report series published from 1994 until January 2001 which lists all known declassification actions and their dates. Hosted by Federation of American Scientists. 1981:, about half of which was to be constructed through a series of underground nuclear explosions. It was reported that about 250 nuclear devices might be used to get the final goal. The 1251:

of the two metals (aluminium is easier and safer to shape, and is two orders of magnitude cheaper; beryllium has high neutron-reflective capability). Fat Man used an aluminium pusher.

5870: 3738: 1934:

In response to the public alarm over fallout, an effort was made to design a clean multi-megaton weapon, relying almost entirely on fusion. The energy produced by the fissioning of

1647:

if exposed to the intense radiation of a nearby nuclear explosion (electronics might also be damaged, but this was a separate problem). RI was a particular problem before effective

643: 3064:

When testing resumed in 1961, and continued for three decades, there was sufficient time to make all warhead designs inherently one-point safe, without need for mechanical safing.

2663:

into equations to make the simulations match experimental results. They also analyzed the weapon debris in fallout to see how much of a potential nuclear reaction had taken place.

2180:): 15,000 times more intense at 1 hour; 35 times more intense at 1 week; 5 times more intense at 1 month; and about equal at 6 months. Thereafter fission drops off rapidly so that 1044:

This condition of spontaneous fission highlights the necessity to assemble the supercritical mass of fuel very rapidly. The time required to accomplish this is called the weapon's

800: 6456: 1923:

at Bikini Atoll, delivered a promptly lethal dose of fission-product fallout to more than 6,000 square miles (16,000 km) of Pacific Ocean surface. Radiation injuries to

4693: 1772:

As with boosting, the advantages of the two-stage thermonuclear design are so great that there is little incentive not to use it, once a nation has mastered the technology.

3235:, Third Edition, 1977, U.S. Dept of Defense and U.S. Dept of Energy (see links in General References, below), with the same information in more detail in Samuel Glasstone, 2262:

During the mid-1950s through early 1960s, scientists working in the weapons laboratories of the United States investigated weapons concepts as large as 1,000 megatons, and

2465:, tampers, predetonation, and three methods of assembling a bomb: gun assembly, implosion, and "autocatalytic methods", the one approach that turned out to be a dead end. 4504: 4255: 3846: 2064:

lasers could also potentially be used this way, if they could be made powerful-enough, and compact-enough, to be viable as a weapon. Most of these ideas are versions of

1742:

The primary's fission reaction has run to completion, and the primary is now at several million degrees and radiating gamma and hard X-rays, heating up the inside of the

3474:

wartime output of Oralloy produced at Oak Ridge by July 28, 1945, was 165 pounds (75 kg). Of this amount, 84% was scattered over Hiroshima (see previous footnote).

2859:

When two-stage weapons became standard in the early 1950s, weapon design determined the layout of the new, widely dispersed U.S. production facilities, and vice versa.

1560:

pit is perfected, there is little reason not to boost; deuterium and tritium are easily produced in the small quantities needed, and the technical aspects are trivial.

3451:

Parsons, Keith M.; Zaballa, Robert A. (2017). Bombing the Marshall Islands: A Cold War Tragedy. Cambridge University Press. pp. 53–56. ISBN 978-1-108-50874-2

2735:

lithium-6 as the product of an (n, 2n) reaction (one neutron in, two neutrons out), a known fact, but with unknown probability. The probability turned out to be high.

1947:. This shot used non-fissionable tampers; an inert substitute material such as tungsten or lead was used. Its yield was 3.5 megatons, 85% fusion and only 15% fission. 1119:

it delays the thermal expansion of the fissioning fuel mass, keeping it supercritical for longer. Often the same layer serves both as tamper and as neutron reflector.

6650: 4093:"Radiological investigations at the "Taiga" nuclear explosion site, part II: man-made γ-ray emitting radionuclides in the ground and the resultant kerma rate in air" 3975: 1905:

Bassoon, the prototype for a 9.3-megaton clean bomb or a 25-megaton dirty bomb. Dirty version shown here, before its 1956 test. The two attachments on the left are

4217: 1312:. As plutonium cools, changes in phase result in distortion and cracking. This distortion is normally overcome by alloying it with 30–35 mMol (0.9–1.0% by weight) 4139: 2950:) was inserted into the bomb in flight, shortly after takeoff on August 6, 1945. This was the first time a gun-type nuclear weapon had ever been fully assembled. 2198:

fallout is 8 times more intense than fission at 1 year and 150 times more intense at 5 years. The very long-lived isotopes produced by fission would overtake the

2785:

section of the NTS is covered with subsidence craters resulting from the collapse of terrain over radioactive caverns created by nuclear explosions (see photo).

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are the simplest, least technically demanding, were the first nuclear weapons built, and so far the only type ever used in warfare, by the United States on

4176: 3636: 1055:

There is another source of free neutrons that can spoil a fission explosion. All uranium and plutonium nuclei have a decay mode that results in energetic

5585: 1346:

Because plutonium is chemically reactive it is common to plate the completed pit with a thin layer of inert metal, which also reduces the toxic hazard.

5880: 5285: 4720: 248: 1589:

Since the mass of the metal being imploded (tamper plus pit) is reduced, a smaller charge of high explosive is needed, reducing diameter even further.

5088: 4615: 2579: 3024:

Alternatively, the pit can be "safed" by having its normally hollow core filled with an inert material such as a fine metal chain, possibly made of

6761: 4574:

The Air Force and Strategic Deterrence 1951–1960. USAF historical division Liaison Office by George F. Lemmer 1967, p. 13. Formerly restricted data

4525: 6906: 4450: 3929:"The 'Alarm Clock' ... became practical only by the inclusion of Li6 (in 1950) and its combination with the radiation implosion." Hans A. Bethe, 2562:, and in 1954, a two-stage thermonuclear device in which the secondary heated up prematurely, too fast for radiation implosion to work properly. 525:{\displaystyle \ {}^{235}\mathrm {U} +\mathrm {n} \longrightarrow {}^{95}\mathrm {Sr} +{}^{139}\mathrm {Xe} +2\ \mathrm {n} +180\ \mathrm {MeV} } 320: 86:

Most known innovations in nuclear weapon design originated in the United States, though some were later developed independently by other states.

2816: 2027:

Project Prometheus, also known as "Nuclear Shotgun", which would have used a nuclear explosion to accelerate kinetic penetrators against ICBMs.

1391:, in 1948, used Fat Man designs with levitated pits. The largest yield was 49 kilotons, more than twice the yield of the unlevitated Fat Man. 5565: 5026: 3675: 3595: 254: 4646: 5887: 5318: 3734: 3212: 2554:

With its original mission no longer available, the Livermore lab tried radical new designs that failed. Its first three nuclear tests were

1639:. It had a dimension of just 11 inches (28 cm), and is shown here in comparison to its Fat Man predecessor (60 inches (150 cm)). 315: 304: 3760: 3164: 2637: 2503:

In 1945, using the results of critical mass experiments, Los Alamos technicians fabricated and assembled components for four bombs: the

5653: 5189: 5104:

Nuclear Weapons: Principles, Effects and Survivability (Land Warfare: Brassey's New Battlefield Weapons Systems and Technology, vol 10)

4685: 4008: 3559: 2620:

facility at Livermore in the mid-1980s, nuclear design activity pertaining to radiation-driven implosion was informed by research with

325: 4576: 2633: 6156: 4027: 3370:

A simplistic computation of the work done in imploding a 10 liter secondary in the "W-80" ... the primary actually produced (5 kt)...

2720:

and across the inside of the bunker. (The nearest people were 20 miles (32 km) farther away, in a bunker that survived intact.)

1602:

The first device whose dimensions suggest employment of all these features (two-point, hollow-pit, fusion-boosted implosion) was the

356: 6395: 2655:

It was easy enough to design reliable weapons for the stockpile. If the prototype worked, it could be weaponized and mass-produced.

1335:. A drawback is that gallium compounds are corrosive and so if the plutonium is recovered from dismantled weapons for conversion to 786:(n), only in a nuclear reactor. This neutron bombardment will cause the lithium-6 nucleus to split, producing an alpha particle, or 2523:

All of the essential ideas for incorporating fusion into nuclear weapons originated at Los Alamos between 1946 and 1952. After the

2155:

Such "salted" weapons were investigated by U.S. Department of Defense. Fission products are as deadly as neutron-activated cobalt.

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on April 7, 1954. The primary ignited, but the secondary, preheated by the primary's neutron wave, suffered what was termed as an

2158:

Initially, gamma radiation from the fission products of an equivalent size fission-fusion-fission bomb are much more intense than

1943:

the tertiary, being ignited by the secondary, was May 27, 1956, in the Bassoon device. This device was tested in the Zuni shot of

1732:

Warhead before firing. The nested spheres at the top are the fission primary; the cylinders below are the fusion secondary device.

1308:

Casting and then machining plutonium is difficult not only because of its toxicity, but also because plutonium has many different

575:

in the X-ray spectrum. These X-rays are absorbed by the surrounding air, producing the fireball and blast of a nuclear explosion.

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https://direct.mit.edu/jcws/article-abstract/23/2/133/101892/Ripple-An-Investigation-of-the-World-s-Most?redirectedFrom=fulltext}

3933: 2712:; thus, a weapon with a predicted one-megaton yield produced only 110 kilotons, of which merely 10 kt were attributed to fusion. 1382:

series of nuclear-weapons tests in 1948 proved the feasibility of increased yield efficiency via the levitated-pit design method.

1213:. It is estimated that only about 20% of the plutonium underwent fission; the rest, about 5 kg (11 lb), was scattered. 6526: 3836: 2298:(10+ km in diameter), which would be employed in the event that one of these asteroids were on an impact trajectory with Earth. 6351: 4488: 4239: 2549: 2537: 2283: 1475: 1209:

three weeks earlier, of the conventional explosives placed uniformly around the pit. The explosives were detonated by multiple

963: 598: 269: 259: 2437:, had just been hired to run the nation's secret bomb design effort. His first act was to convene the 1942 summer conference. 2295: 5580: 5175: 5157: 5127: 4498: 3909: 3803: 3493: 3409: 2420: 285: 274: 264: 5137: 4753: 6402: 4733: 2575: 2567: 1606:

device. It had a cylindrical shape with a diameter of 11.6 in (29 cm) and a length of 22.8 in (58 cm).

189: 3194:

detonation on August 12, 1953, said to be the first deliverable hydrogen bomb. However, as Herbert York first revealed in

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neutrons, and among the many ways to do this, adding a fusion reaction was relatively easy in the case of a hollow pit.

618:

production of very large nuclear arsenals, in comparison to pure fission weapons requiring the expensive U or Pu fuels.

7017: 6601: 5053: 4798: 4671: 4542: 4460: 4249: 4211: 4149: 3030: 2648:

Nuclear weapons are in large part designed by trial and error. The trial often involves test explosion of a prototype.

2571: 2426: 2092: 2046: 5043: 3583:, October 1995, Chucklea Productions, Volume VIII, p. 154, Table A-1, "U.S. Nuclear Detonations and Tests, 1945–1962". 1165: 5681: 5560: 4952: 4299: 3890: 3815: 3207: 2846: 2010:, which was to be carried by U.S. Air Force bombers until it was decommissioned; this weapon was never fully tested. 1543:

of the Greenhouse-series of tests was the first nuclear weapon device to achieve yield utilizing boosting-principles.

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continues to fission in the neutron-rich environment until it is fully consumed, adding significantly to the yield.

4830: 3768: 2445:, transcribed and distributed as the (classified but now fully declassified and widely available online as a PDF) 1289:

The core of an implosion weapon – the fissile material and any reflector or tamper bonded to it – is known as the

6854: 6688: 6290: 6168: 5825: 5686: 5122:" (CD-ROM & download available). PDF. 2,600 pages, Sunnyvale, California, Chucklea Publications, 1995, 2007. 3652: 2091:

ability to be used without producing fallout on the scale of weapons that release fission products. In 1998, the

1977:

The most ambitious peaceful application of nuclear explosions was pursued by the USSR with the aim of creating a

1802: 1958:

The public records for devices that produced the highest proportion of their yield via fusion reactions are the

1258:

tests of implosion-type fission weapon design concepts, carried out from July 1944 through February 1945 at the

7145: 6844: 6693: 6151: 3633: 2602: 2474: 1794: 1682: 1636: 1479: 1210: 1157: 967: 727:{\displaystyle {}^{2}\mathrm {D} +{}^{3}\mathrm {T} \longrightarrow {}^{4}\mathrm {He} +n+17.6\ \mathrm {MeV} } 5083:

Coster-Mullen, John, "Atom Bombs: The Top Secret Inside Story of Little Boy and Fat Man", Self-Published, 2011

4046:"Radiological investigations at the "Taiga" nuclear explosion site: Site description and in situ measurements" 3634:

So I pieced together from Edward's testament and from his memoir that Stan had come to him in February of 1951

3215:, "Perfectionnements aux charges explosives (Improvements to explosive charges)", published 1951-01-16 2068:, and share the common property that they involve hitherto unrealized technologies as their "primary" stages. 6618: 6451: 5875: 5803: 2931: 887:{\displaystyle {}^{6}\mathrm {Li} +n\longrightarrow {}^{4}\mathrm {He} +{}^{3}\mathrm {T} +5\ \mathrm {MeV} } 349: 167: 5186: 2997:

As shown in the diagram above, one method used to decrease the likelihood of accidental detonation employed

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Gsponer, Andre (2005). "Fourth Generation Nuclear Weapons: Military effectiveness and collateral effects".

2430: 2492:

had to wait until sufficient amounts of fissile material arrived from the production plants: uranium from

2259:

literature about two-stage weapons, but no similarly accurate descriptions of true three stage concepts."

1169:

undoubtedly a combination of the lower yield and grave safety issues associated with the gun-type design.

23:

The first nuclear explosive devices provided the basic building blocks of future weapons. Pictured is the

7111: 7024: 6996: 6953: 6918: 6756: 6583: 6521: 6346: 6250: 6136: 5604: 5304: 4594: 3663:, American Institute of Physics interview with Marshall Rosenbluth by Kai-Henrik Barth, dated August 2003 3006: 2271:, instead resulted in lower-yield, highly-compact warheads that gave greater options for deliverability. 2072: 1753:

The secondary's fuel has started the fusion reaction and shortly will burn up. A fireball starts to form.

330: 1305:, but all-plutonium pits are the smallest in diameter and have been the standard since the early 1960s. 1285:

Flash X-Ray images of the converging shock waves formed during a test of the high explosive lens system.

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decided he needed his own laboratory in order to pursue H-bombs. By the time it was opened in 1952, in

1959: 1686:

Mathematical simulations showed it would not work, even with large amounts of expensive tritium added.

1010:

was the first ever pure-fission nuclear device to be detonated, with an estimated yield of 25-kilotons.

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Y-12 made lithium-6 deuteride fusion fuel and U-238 parts, the other two ingredients of secondaries.

2789: 2034: 101:. Practitioners of nuclear policy, however, favor the terms nuclear and thermonuclear, respectively. 2006:, a three-stage thermonuclear weapon with a maximum "dirty" yield of 25 megatons, designated as the 7150: 7029: 6871: 6771: 6683: 5892: 5778: 5738: 5550: 2142: 1464: 1328: 952: 552: 342: 155: 19: 5286:

Annotated bibliography on nuclear weapons design from the Alsos Digital Library for Nuclear Issues

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It was first tested standalone and then as the primary of a two-stage thermonuclear device during

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The first systematic exploration of nuclear weapon design concepts took place in mid-1942 at the

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The easiest fusion reaction to achieve is found in a 50–50 mixture of tritium and deuterium. For

1468: 1317: 1309: 1136: 956: 775:

when these neutrons collide with the lithium nuclei in the bomb's lithium deuteride fuel supply.

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Gun assembly type bomb would not work for plutonium because of predetonation problems caused by

2099:(1) Fact that the DOE made a substantial investment in the past to develop a pure fusion weapon 1962:

of the 1970s. Others include the 10 megaton Dominic Housatonic at over 99.9% fusion, 50 megaton

1617:

and became the first off-the-shelf, multi-use primary, and the prototype for all that followed.

753:

is fission and the release of 180 MeV of fission energy, multiplying the energy output tenfold.

7155: 6766: 6053: 5597: 4995: 4944: 3518:– "Fact that plutonium and uranium may be bonded to each other in unspecified pits or weapons." 3105: 2824: 2458: 2433:, such as the 1940 cyclotron-made production and isolation of plutonium. A Berkeley professor, 2275: 2224: 1978: 1798: 1603: 1531: 1185: 1127: 1020: 60: 4091:

Ramzaev, V.; Repin, V.; Medvedev, A.; Khramtsov, E.; Timofeeva, M.; Yakovlev, V. (July 2012).

4044:

Ramzaev, V.; Repin, V.; Medvedev, A.; Khramtsov, E.; Timofeeva, M.; Yakovlev, V. (July 2011).

1586:

The mass of the pit can be reduced by half, without reducing yield. Diameter is reduced again.

7060: 6796: 6751: 6213: 6141: 6068: 6063: 6028: 5815: 5570: 5497: 3382: 3154: 3141: 3086: 2901: 2591: 2587: 2555: 2484: 2434: 2040: 1885:, April 26, 1954, was a two-stage thermonuclear device code-named Alarm Clock. Its yield, at 1259: 1115:

A tamper is an optional layer of dense material surrounding the fissile material. Due to its

224: 209: 5216: 5014: 4936: 4348: 4005: 3643:

American Institute of Physics interview with Richard Garwin by Ken Ford, dated December 2012

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Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945

2744: 1928: 6971: 6746: 6731: 6048: 6006: 5842: 5748: 5676: 5010: 4415: 4371: 4104: 4057: 2962: 2867: 2559: 2513: 2493: 2137: 2003: 1967: 1706: 1661: 1568: 1355: 1276: 1089: 1028: 572: 548: 172: 160: 69: 4024: 3867: 2617: 1815:(and small) heat explosion before the fusion and fission reactions get a chance to start. 1705:

The concept of radiation implosion was first tested on May 9, 1951, in the George shot of

8: 7070: 6881: 6666: 6260: 6128: 6106: 5931: 5788: 5555: 5517: 5350: 5290: 5266:(PDF) from the US Department of Defense at the Federation of American Scientists website. 4490:

Weapons of Mass Destruction: An Encyclopedia of Worldwide Policy, Technology, and History

2983: 2979: 2958: 2897: 2677:

The picture below shows the Shrimp device, detonated on March 1, 1954, at Bikini, as the

2594:

I missile started out as a Livermore project, was given to Los Alamos when it became the

1648: 1388: 1321: 1232:

backward, thereby having the effect of lengthening its duration. It is made out of a low

1037: 906: 779: 214: 38:

are physical, chemical, and engineering arrangements that cause the physics package of a

4573: 4419: 4375: 4108: 4061: 1147: 7050: 6786: 6623: 6550: 6361: 6011: 5981: 5965: 5948: 5592: 5482: 5430: 5380: 5327: 5258: 5181: 5045:

From Polaris to Trident: The Development of the U.S. Fleet Ballistic Missile Technology

4519: 4277: 3789:"Improved Security, Safety & Manufacturability of the Reliable Replacement Warhead" 2610: 2524: 2247: 2085: 2065: 1750:

radiation case is also ablating and expanding outward (omitted for clarity of diagram).

1298: 1072: 1064: 920:

Most lithium is Li, and this gave Castle Bravo a yield 2.5 times larger than expected.

3986: 3930: 3810:

which depicts an interstage that absorbs and re-radiates x-rays. From Howard Morland,

2105:(3) That no credible design for a pure fusion weapon resulted from the DOE investment. 568:

several meters in diameter with a temperature of tens of millions of degrees Celsius.

6118: 5911: 5798: 5773: 5711: 5668: 5512: 5507: 5502: 5345: 5171: 5153: 5123: 5049: 4948: 4937: 4921:

Dr. John C. Clark, as told to Robert Cahn, "We Were Trapped by Radioactive Fallout",

4794: 4494: 4456: 4431: 4387: 4245: 4207: 4145: 4120: 4073: 3489: 3249: 3213:

Caisse Nationale de la Recherche Scientifique (National Fund for Scientific Research)

3073:

design and make it inherently one-point safe. A solution was devised consisting of a

2954: 2883: 2875: 2729: 2446: 2030: 1998: 1990: 1971: 1952: 1944: 1610: 1336: 1101: 1085: 578:

Most fission products have too many neutrons to be stable so they are radioactive by

544: 219: 204: 199: 194: 130: 5237: 2989:

In-flight pit insertion will not work with a hollow pit in contact with its tamper.

2660: 2152:; the material added to the bombs is referred to in the film as 'cobalt-thorium G'. 6966: 6021: 5986: 5743: 5733: 5621: 5609: 5450: 5445: 5435: 5425: 5420: 5263: 5018: 4423: 4379: 4112: 4065: 2775: 2007: 1920: 1882: 1866: 1797:

what it reported as its first "two-stage thermo-nuclear weapon" test. According to

1698:

invented radiation implosion – for nearly three decades known publicly only as the

1424: 1153: 1092:

which bombards a deuterium/tritium-metal hydride target with deuterium and tritium

565: 4452:

The Release of Thermonuclear Energy by Inertial Confinement: Ways Towards Ignition

4427: 4383: 4116: 4069: 3906: 3800: 2112:, a likely hoax substance, has been hyped as a catalyst for a pure fusion weapon. 1362:

became the preferred material. Recent designs improve safety by plating pits with

6864: 6824: 6278: 6092: 6016: 5991: 5837: 5630: 5532: 5522: 5487: 5365: 5355: 5193: 5141: 5119: 5095: 5073: 4834: 4745: 4580: 4331: 4303: 4031: 4012: 3993: 3937: 3913: 3894: 3874: 3819: 3807: 3716: 3679: 3660: 3640: 3599: 3563: 3515: 3159: 2909: 2771: 2454: 2148: 1709:, Eniwetok, yield 225 kilotons. The first full test was on November 1, 1952, the 1620: 1564: 1340: 1255: 547:

with nearby nuclei, and these fragments remain trapped inside the bomb's fissile

388: 140: 50: 6356: 4815:

Warhead Politics: Livermore and the Competitive System of Nuclear Warhead Design

3163:, vol. 51, no. 19, November 10, 1961, New York, pp. 34–37, 1961, 2685: 2480: 2102:(2) That the U.S. does not have and is not developing a pure fusion weapon; and 1877:

on August 12, 1953. No single-stage U.S. version was tested, but the code named

1673:, the first two-stage thermonuclear detonation, 10.4 megatons, November 1, 1952. 1281: 6819: 6814: 6809: 6559: 6466: 6435: 6417: 5941: 5847: 5793: 5758: 5691: 5638: 5492: 5385: 5370: 5360: 5291:

The Woodrow Wilson Center's Nuclear Proliferation International History Project

5163: 3299: 3115: 2998: 2905: 2697: 1915:

On March 1, 1954, the largest-ever U.S. nuclear test explosion, the 15-megaton

1695: 1572: 1563:

The concept of fusion-boosted fission was first tested on May 25, 1951, in the

1056: 1045: 627: 560: 229: 177: 107: 39: 6839: 5269: 5022: 4336:. U.S. Department of Defense, U.S. Atomic Energy Commission. pp. 464–466. 4316: 3528: 3508: 7139: 7004: 6295: 5701: 5542: 2533: 2462: 2442: 2287: 2263: 1736: 1714: 1691: 1644: 1614: 1536: 1432: 1407: 1049: 1015: 540: 2540:, California, Los Alamos had finished the job Livermore was designed to do. 1997:

tamper in place, was tested on a barge off the coast of Bikini Atoll as the

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properly. Even today's computers and simulation software are not adequate.

2598:

missile warhead, and in 1959 was given back to Livermore, in trade for the

2517: 2505: 2497: 2307: 1916: 1886: 1878: 1666: 1578:

Boosting reduces diameter in three ways, all the result of faster fission:

1552: 1177: 1002: 902: 778:

Elemental gaseous tritium for fission primaries is also made by bombarding

741: 54: 28: 5275: 4296: 3886: 3811: 1979:

112 km long canal between the Pechora river basin and the Kama river basin

1931:

made that fact public and revealed the role of fission in hydrogen bombs.

1216: 1199: 909:

is present, one also has some amounts of the following two net reactions:

597:. The two fissile materials used in nuclear weapons are: U, also known as 6981: 6628: 6218: 5725: 5696: 4317:"Restricted Data Declassification Decisions, 1946 to the Present (RDD-7)" 3709: 3567: 3239:, Third Edition, 1979, U.S. Atomic Energy Commission, Krieger Publishing. 3002: 2705: 2595: 2133: 2127: 2121: 2109: 1994: 1939: 1935: 1699: 1294: 1205: 394: 89:

In early news accounts, pure fission weapons were called atomic bombs or

75: 4282: 3012: 2274:

Following the concern caused by the estimated gigaton scale of the 1994

1735:

Fission primary's explosives have detonated and collapsed the primary's

1223: 6334: 5134: 4827: 3422:"neutrons carry off most of the reaction energy", Glasstone and Dolan, 3231:

The main source for this section is Samuel Glasstone and Philip Dolan,

3176: 2782: 2509: 2060: 1963: 1347: 1141: 583: 579: 24: 4672:"An Unearthly Spectacle: The Untold Story of the World's Biggest Bomb" 3735:"North Korea hydrogen bomb: Read the full announcement from Pyongyang" 6976: 6339: 6329: 5457: 5410: 5375: 5296: 5248:

provides solid information on weapons of mass destruction, including

5078:

The Truth About the Neutron Bomb: The Inventor of the Bomb Speaks Out

3581:

The Swords of Armageddon: U.S. Nuclear Weapons Development since 1945

2871: 2701: 2294:

weapons designers that they collaborate on designing a 1,000-megaton

2159: 1873:), a layered pastry cake. A single-stage Soviet Sloika was tested as 1724: 1332: 1302: 1244: 1240: 1080: 606: 402: 6834: 5270:"Restricted Data Declassification Decisions from 1946 until Present" 5233:

is a reliable source of information and has links to other sources.

5230: 3616: 3529:"Restricted Data Declassification Decisions from 1946 until Present" 3509:"Restricted Data Declassification Decisions from 1945 until Present" 2149:

Dr. Strangelove or: How I Learned to Stop Worrying and Love the Bomb

1453: 941: 586:. In bombs, they become radioactive fallout, both local and global. 7065: 6708: 6703: 6643: 6312: 6240: 6223: 6208: 6183: 5926: 5415: 4717:"The mother of all bombs would sit in wait in an orbitary platform" 2879: 2291: 2020: 1743: 1710: 1670: 1632:

warhead, was closer to a sphere, only 15 inches (38 cm) long.

1593: 1363: 1227:

Small-scale slow-motion cut-away of shaped-charge implosion device.

1076: 1014:

The first task of a nuclear weapon design is to rapidly assemble a

3602:, accessed December 1, 2007. Drawing adapted from the same source. 3300:"Nuclear explained – U.S. Energy Information Administration (EIA)" 7034: 6986: 6849: 6829: 6228: 6203: 5643: 5474: 5462: 5440: 5405: 5113:

Swords of Armageddon: U.S. Nuclear Weapons Development since 1945

3579:

All information on nuclear weapon tests comes from Chuck Hansen,

3025: 2947: 2450: 2296:

nuclear explosive device for diverting extinction-class asteroids

2279: 1824: 1820: 1313: 1233: 1189: 1116: 783: 771: 766: 610: 594: 4487:

Croddy, Eric A.; Wirtz, James J.; Larsen, Jeffrey, Eds. (2005).

3837:"Technical hitch delays renewal of nuclear warheads for Trident" 3610: 3608: 1901: 1374: 901:

But as was discovered in the first test of this type of device,

6638: 6633: 6613: 6593: 6578: 6461: 6198: 6178: 6146: 4179:. Educational Foundation for Nuclear Science, Inc. March 1991. 2570:, IRBMs, but smaller Livermore warheads were used on the first 2488: 1874: 1848: 1351: 1193: 787: 5282:, with links to supporting documents on nuclear weapon design. 2925: 2624:

laser fusion. This work was part of the effort to investigate

7055: 7012: 6675: 6531: 6324: 6188: 5112: 4895: 4864: 4404: 4361: 4090: 4043: 3605: 3191: 3074: 2815:

deal primarily with the United States and do not represent a

2220: 2049:

explored the use of nuclear explosives for rocket propulsion.

1324: 1248: 1236: 406: 115: 5264:

Militarily Critical Technologies List (MCTL), Part II (1998)

2586:

specialty. Some designs were horse-traded. For example, the

2429:. Important early discoveries had been made at the adjacent 757:

rather than to use them to increase the weapon's raw power.

393:

When a free neutron hits the nucleus of a fissile atom like

6536: 6425: 6235: 6193: 4547: 2325:

are very difficult to harden against extreme neutron flux.

1989:

On July 19, 1956, AEC Chairman Lewis Strauss said that the

1359: 1293:. Some weapons tested during the 1950s used pits made with 556: 539:

The immediate energy release per atom is about 180 million

4793:(1st ed.). Berkeley: University of California Press. 3140:

weapons. For a photograph of a modern physics package see

42:

to detonate. There are three existing basic design types:

6509: 6373: 3341:

high explosive containing essentially no high-Z material.

3058: 2599: 2399: 2395: 2253: 1827:, possibly doped with beryllium and/or other substances. 1629: 1436: 1104:, all of which affect the escape or capture of neutrons. 1093: 5259:

More information on the design of two-stage fusion bombs

5249: 4340: 3155:"To the Outside World, a Superbomb more Bluff than Bang" 1861:

into the secondary of a two-stage thermonuclear weapon.

593:

Materials which can sustain a chain reaction are called

3593:

Nuclear Weapons FAQ: 4.1.6.3 Hybrid Assembly Techniques

3250:"nuclear fission | Examples & Process | Britannica" 2893:

the N-Reactor which ceased operations in January 1987.

16:

Process by which nuclear WMDs are designed and produced

3987:

4.5 Thermonuclear Weapon Designs and Later Subsections

1522:

tamper, no aluminium pusher, and less high explosive.

765:

An essential nuclear reaction is the one that creates

5238:

Section 4.0 Engineering and Design of Nuclear Weapons

3943: 3397: 2613:

and the dismantlement of the large high-yield bombs.

1514:

A more efficient implosion system uses a hollow pit.

803: 646: 422: 4034:. Nuclearweaponarchive.org. Retrieved on 2011-05-01. 4015:. Nuclearweaponarchive.org. Retrieved on 2011-05-01. 3996:. Nuclearweaponarchive.org. Retrieved on 2011-05-01. 3682:. Nuclearweaponarchive.org. Retrieved on 2011-05-01. 3050:

after Swan, both labs began one-point safety tests.

5245: 3196:

The Advisors: Oppenheimer, Teller and the Superbomb

2766:

Subsidence Craters at Yucca Flat, Nevada Test Site.

1343:, there is the difficulty of removing the gallium. 1063:effects of other nuclear detonations, it is called 6059:Blue Ribbon Commission on America's Nuclear Future 3931:Memorandum on the History of Thermonuclear Program 2605:warhead, which went from Livermore to Los Alamos. 2071:While many nations have invested significantly in 886: 726: 524: 375:bombs, which a French patent claimed in May 1939. 5086:Glasstone, Samuel and Dolan, Philip J., editors, 4993: 4486: 3761:"Israel's Nuclear Weapon Capability: An Overview" 2043:that focus their energy in particular directions. 1327:would also work, but gallium has a small neutron 1196:, which is only 41% of bare-sphere critical mass 7137: 3029:contaminate the surroundings as has happened in 2290:proposed to a collective of U.S. and Russian ex- 1637:Davy Crockett XM-388 recoilless rifle projectile 1152:. When assembled inside its tamper/reflector of 5089:The Effects of Nuclear Weapons (third edition) 3887:"SAND8.8 – 1151 Nuclear Weapon Data – Sigma I" 2863:plutonium and beryllium fabrication facility. 2628:. Similar work continues at the more powerful 1423:explosive mass, this requires the pit to be a 6762:Small sealed transportable autonomous (SSTAR) 5312: 5145:, Office of Technology Assessment (May 1979). 5099:(PDF), U.S. Government Printing Office, 1977. 4994:Harvey, John R.; Michalowski, Stefan (1994). 3726: 3434: 3432: 2813:The examples and perspective in this section 2479:At Los Alamos, it was found in April 1944 by 2405: 1806:have single-stage weapons, possibly boosted. 1402: 555:until their kinetic energy is converted into 350: 5236:Nuclear Weapons Frequently Asked Questions: 5211: This article incorporates text from a 4996:"Nuclear Weapons Safety:The Case of Trident" 4524:: CS1 maint: multiple names: authors list ( 4241:The Role and Control of Weapons in the 1990s 4203:SDI: Technology, survivability, and software 4141:The Role and Control of Weapons in the 1990s 3552: 3550: 2634:Stockpile Stewardship and Management Program 2223:test, as part of the preliminary March 1971 4669: 4592: 3673:4.4 Elements of Thermonuclear Weapon Design 3488:. Cambridge University Press. p. 271. 3325:"NWFAQ: 4.2.5 Special Purpose Applications" 2992: 1635:One of the applications of the W54 was the 1482:. Unsourced material may be challenged and 1358:vapors was used, but thereafter and since, 1088:is a high-voltage vacuum tube containing a 970:. Unsourced material may be challenged and 559:. Given the speed of the fragments and the 5319: 5305: 5197:, Princeton University Press, 1945. (see: 4714: 4448: 3834: 3429: 3355:"NWFAQ: 4.4.3.4 Principles of Compression" 3033:, it could not cause a nuclear explosion. 2968: 2831:, or create a new section, as appropriate. 2636:also benefited from research performed at 1655: 1369: 357: 343: 114: 5168:Dark Sun: The Making of the Hydrogen Bomb 4939:Dark Sun; the Making of the Hydrogen Bomb 4884: 4329: 4281: 3547: 3408:sfn error: no target: CITEREFRhodes1986 ( 3099: 2847:Learn how and when to remove this message 2560:fission devices with uranium hydride pits 1746:, the shield, and the secondary's tamper. 1525: 1502:Learn how and when to remove this message 1350:used galvanic silver plating; afterward, 990:Learn how and when to remove this message 409:(Xe), and two neutrons (n), plus energy: 93:and weapons involving fusion were called 6674: 4853: 4306:. Whyfiles.org. Retrieved on 2011-05-01. 3570:, Carey Sublette, accessed Sept 23, 2006 3483: 3080: 2924: 2916: 2795: 2761: 2023:but were never deployed. These include: 1900: 1847: 1723: 1665: 1535: 1373: 1331:and helps protect the plutonium against 1280: 1222: 1126: 1001: 18: 5231:Carey Sublette's Nuclear Weapon Archive 4593:Wellerstein, Alex (12 September 2012). 4537: 4535: 4275: 4237: 4137: 3484:Hoddeson, Lillian; et al. (2004). 2449:. The Primer addressed fission energy, 1443: 931: 790:-4 (He), plus a triton (T) and energy: 7138: 6689:Liquid-fluoride thorium reactor (LFTR) 5326: 5276:The Holocaust Bomb: A Question of Time 5170:. Simon and Schuster, New York, (1995 5152:. Simon and Schuster, New York, (1986 4934: 4890: 4859: 4788: 4782: 4455:. World Scientific. pp. 192–193. 4408:Journal of Environmental Radioactivity 4364:Journal of Environmental Radioactivity 4097:Journal of Environmental Radioactivity 4050:Journal of Environmental Radioactivity 3949: 3877:, March 7, 2008. (Accessed 2010-04-06) 3704: 3702: 3403: 3057:Of particular concern was Livermore's 3019: 2751: 2550:Lawrence Livermore National Laboratory 2284:Lawrence Livermore National Laboratory 2254:Arbitrarily large multi-staged devices 2079: 1366:to make the pits more fire-resistant. 6931: 6694:Molten-Salt Reactor Experiment (MSRE) 6103: 6090: 5300: 4746:"Neutron bomb: Why 'clean' is deadly" 4670:Wellerstein, alex (29 October 2021). 3741:from the original on 4 September 2017 3521: 3067: 2576:submarine-launched ballistic missiles 2568:intermediate-range ballistic missiles 2543: 2421:Lawrence Berkeley National Laboratory 1843: 760: 7118: 6091: 5278:is an update of the 1979 court case 4734:planetary defense workshop LLNL 1995 4674:. Bulletin of the Atomic Scientists. 4532: 4346: 3897:Sandia Laboratories, September 1988. 3732: 3614: 3352: 3322: 2953:If the weapon falls into water, the 2799: 2643: 2414: 2053: 1728:Ablation mechanism firing sequence. 1480:adding citations to reliable sources 1447: 1131:Diagram of a gun-type fission weapon 1122: 968:adding citations to reliable sources 935: 369: 6699:Integral Molten Salt Reactor (IMSR) 5187:Atomic Energy for Military Purposes 4974: 4828:Declaration for the Wen Ho Lee case 4177:"Bulletin of the Atomic Scientists" 3699: 3036: 2758:Underground nuclear weapons testing 2723: 2572:intercontinental ballistic missiles 2248:fusion generated neutron activation 2013: 1834: 1518:and three tons of high explosives. 1160:at Oak Ridge, scattered uselessly. 13: 6508: 5659:Positron-emission tomography (PET) 4925:, July 20, 1957, pp. 17–19, 69–71. 4756:from the original on April 7, 2009 3011: 2684: 2427:University of California, Berkeley 2093:United States Department of Energy 2033:, a nuclear-pumped X-ray laser to 1619: 1592: 1406: 1215: 1176: 880: 877: 874: 860: 843: 840: 817: 814: 740: 720: 717: 714: 694: 691: 674: 657: 518: 515: 512: 498: 484: 481: 464: 461: 444: 436: 14: 7167: 5682:Neutron capture therapy of cancer 5581:Radioisotope thermoelectric (RTG) 5246:Federation of American Scientists 5224: 3849:from the original on 5 March 2016 3535:from the original on 4 April 2020 2578:, SLBMs, as well as on the first 2132:A doomsday bomb, made popular by 1970:test at 95%, and the 4.5 megaton 1717:, Eniwetok, yield 10.4 megatons. 1172: 7117: 7106: 7105: 7093: 6782:Fast Breeder Test Reactor (FBTR) 5218:Nuclear Weapons FAQ: 1.6 5206: 5080:, William Morrow & Co., 1983 5032:from the original on 2012-10-16. 2804: 2696:logjam to retard the passage of 2301: 2004:yield-to-weight weapon ever made 1951:for a 15 kt/kg were made during 1907: 1761:(355 kilotons, vs 15 kilotons). 1681:In the 1940s, bomb designers at 1452: 1270: 940: 5871:Historical stockpiles and tests 5066: 5036: 4987: 4961: 4928: 4915: 4904:from the original on 2016-12-30 4873:from the original on 2016-12-30 4840: 4820: 4807: 4768: 4727: 4715:Jason Mick (October 17, 2013). 4708: 4696:from the original on 2016-03-20 4678: 4663: 4652:from the original on 2016-10-25 4632: 4621:from the original on 2016-03-04 4601: 4586: 4567: 4555:from the original on 2016-03-05 4507:from the original on 2021-09-04 4480: 4469:from the original on 2021-08-05 4449:Winterberg, Friedwardt (2010). 4442: 4398: 4355: 4323: 4309: 4290: 4269: 4258:from the original on 2021-09-04 4231: 4220:from the original on 2021-09-04 4194: 4183:from the original on 2021-09-04 4169: 4158:from the original on 2021-09-04 4131: 4084: 4037: 4018: 3999: 3980: 3968: 3955: 3923: 3900: 3880: 3861: 3828: 3794: 3782: 3753: 3685: 3666: 3646: 3627: 3617:"Fission-Fusion Hybrid Weapons" 3586: 3573: 3502: 3477: 3467: 3454: 3445: 3416: 3375: 3346: 3316: 3167:from the original on 2021-09-04 2908:, also built in 1952, operated 2115: 1966:at 97% fusion, the 9.3 megaton 1211:exploding-bridgewire detonators 1202:article for a detailed drawing) 1150:article for a detailed drawing) 6772:Energy Multiplier Module (EM2) 5654:Single-photon emission (SPECT) 4943:. Simon and Schuster. p. 4850:, Volume IV, pp. 211–212, 284. 4493:. ABC-CLIO, Inc. p. 376. 4333:The Effects of Nuclear Weapons 3733:Kemp, Ted (3 September 2017). 3292: 3279: 3266: 3242: 3233:The Effects of Nuclear Weapons 3225: 3201: 3183: 3147: 3133: 2778:(NTS) northwest of Las Vegas. 2668: 2475:Los Alamos National Laboratory 2329:Energy distribution of weapon 1896: 916:Li + H → 2 He + n + 15.123 MeV 827: 678: 448: 27:device being prepared for the 1: 7100:Nuclear technology portal 5150:The Making of the Atomic Bomb 5003:Science & Global Security 4543:"Fission, Fusion and Staging" 4428:10.1016/j.jenvrad.2011.12.009 4384:10.1016/j.jenvrad.2011.04.003 4117:10.1016/j.jenvrad.2011.12.009 4070:10.1016/j.jenvrad.2011.04.003 3122: 2882:had enriched uranium for the 2468: 2140:, and subsequent 1959 movie, 1809: 6962:Field-reversed configuration 6572:Uranium Naturel Graphite Gaz 4595:"In Search of a Bigger Boom" 3723:, March 2005, pp. 1401–1408. 2558:: in 1953, two single-stage 2431:Lawrence Berkeley Laboratory 2216:again after about 75 years. 2095:declassified the following: 1911:; see below for elaboration. 1075:" inside the pit containing 379:numbers and approximations. 7: 6919:Aircraft Reactor Experiment 6104: 5866:States with nuclear weapons 4690:Center for Public Integrity 4030:September 10, 2016, at the 4011:September 10, 2016, at the 3835:Ian Sample (6 March 2008). 3237:Sourcebook on Atomic Energy 2940: 2827:, discuss the issue on the 2626:Inertial Confinement Fusion 2219:The triple "taiga" nuclear 2073:inertial confinement fusion 1960:peaceful nuclear explosions 1613:. It was weaponized as the 1197: 1145: 1102:neutron-reflecting material 571:This is hot enough to emit 10: 7172: 6932: 6757:Liquid-metal-cooled (LMFR) 5881:Tests in the United States 5135:The Effects of Nuclear War 4971:, Volume VII, pp. 396–397. 4779:, December 9, 2008, p. D1. 4349:"Nuclear Weapons FAQ: 1.6" 4330:Glasstone, Samuel (1962). 3868:"ArmsControlWonk: FOGBANK" 3103: 3084: 2755: 2727: 2630:National Ignition Facility 2582:systems on such missiles. 2547: 2472: 2418: 2406:Weapon design laboratories 2305: 2125: 2119: 2083: 2035:destroy ballistic missiles 1936:unenriched natural uranium 1659: 1529: 1403:Two-point linear implosion 1274: 1134: 625: 386: 382: 83:infrastructure are built. 7087: 7043: 6995: 6952: 6942: 6894: 6882:Stable Salt Reactor (SSR) 6795: 6777:Reduced-moderation (RMWR) 6742: 6725: 6665: 6592: 6584:Advanced gas-cooled (AGR) 6558: 6549: 6501: 6481: 6434: 6416: 6372: 6277: 6259: 6127: 6114: 6099: 6086: 6041: 5974: 5919: 5910: 5858: 5766: 5757: 5724: 5667: 5629: 5620: 5541: 5473: 5396: 5338: 5334: 5023:10.1080/08929889408426405 4923:The Saturday Evening Post 3873:January 14, 2010, at the 3031:several weapons accidents 2790:Threshold Test Ban Treaty 2496:, and plutonium from the 1870: 1801:, after reviewing leaked 621: 6787:Dual fluid reactor (DFR) 6403:Steam-generating (SGHWR) 5739:Electron-beam processing 5215:work. . Text taken from 4969:The Swords of Armageddon 4935:Rhodes, Richard (1995). 4848:The Swords of Armageddon 3562:October 3, 2006, at the 3359:nuclearweaponarchive.org 3329:Nuclearweaponarchive.org 3175:. Article on the Soviet 3127: 2993:Steel ball safety method 1329:absorption cross section 6902:Organic nuclear reactor 6074:Nuclear power phase-out 5997:Nuclear decommissioning 5937:Reactor-grade plutonium 5687:Targeted alpha-particle 5566:Accidents and incidents 5015:1994S&GS....4..261H 4789:Server, Robert (1992). 4302:April 18, 2016, at the 4238:Barnaby, Frank (2012). 4138:Barnaby, Frank (2012). 3912:March 15, 2016, at the 3907:The Greenpeace drawing. 3893:April 23, 2016, at the 3818:March 22, 2016, at the 3678:March 11, 2016, at the 3598:April 19, 2016, at the 3514:April 23, 2016, at the 2969:In-flight pit insertion 2459:nuclear chain reactions 2282:, in a 1995 meeting at 2269:Limited Test Ban Treaty 1795:North Korea carried out 1656:Two-stage thermonuclear 1575:, yield 45.5 kilotons. 1370:Levitated-pit implosion 1318:plutonium-gallium alloy 1137:Gun-type fission weapon 1046:critical insertion time 599:highly enriched uranium 61:boosted fission weapons 5280:USA v. The Progressive 5221:, Carey Sublette, . 4833:March 8, 2016, at the 4640:"Case No. FIC-15-0005" 4579:June 17, 2014, at the 3992:March 3, 2016, at the 3936:March 4, 2016, at the 3920:, March 2005, p. 1378. 3825:, March 2005, p. 1374. 3806:April 3, 2016, at the 3112:permissive action link 3106:Permissive action link 3100:Permissive action link 3016: 2937: 2767: 2710:inefficient detonation 2689: 2278:impacts on the planet 2276:Comet Shoemaker-Levy 9 2107: 2041:Nuclear shaped charges 1912: 1857: 1757: 1674: 1624: 1597: 1544: 1532:Boosted fission weapon 1526:Fusion-boosted fission 1411: 1383: 1286: 1228: 1220: 1181: 1132: 1021:nuclear chain reaction 1011: 888: 745: 728: 526: 36:Nuclear weapon designs 32: 7146:Nuclear weapon design 6064:Anti-nuclear movement 4791:The Los Alamos Primer 3557:Fissionable Materials 3460:Glasstone and Dolan, 3438:Glasstone and Dolan, 3272:Glasstone and Dolan, 3087:Strong link/weak link 3081:Strong link/weak link 3015: 2974:yield was a concern. 2928: 2917:Warhead design safety 2796:Production facilities 2765: 2688: 2435:J. Robert Oppenheimer 2097: 1904: 1851: 1727: 1669: 1623: 1596: 1539: 1410: 1377: 1284: 1260:Los Alamos Laboratory 1226: 1219: 1180: 1130: 1005: 889: 744: 729: 527: 70:thermonuclear weapons 22: 6972:Reversed field pinch 6767:Traveling-wave (TWR) 6251:Supercritical (SCWR) 5749:Gemstone irradiation 4897:Swords of Armageddon 4866:Swords of Armageddon 4006:Operation Hardtack I 3765:wisconsinproject.org 3621:nuclearweaponarchive 2986:, used this system. 2963:criticality accident 2825:improve this section 2494:Oak Ridge, Tennessee 1974:test at 95% fusion. 1889:, was 6.9 megatons. 1707:Operation Greenhouse 1662:Thermonuclear weapon 1569:Operation Greenhouse 1476:improve this section 1444:Hollow-pit implosion 1435:; an example is the 1356:nickel tetracarbonyl 1277:Pit (nuclear weapon) 1158:giant Y-12 factories 1090:particle accelerator 1029:strong nuclear force 964:improve this section 932:Pure fission weapons 801: 644: 573:black-body radiation 420: 239:Nuclear-armed states 47:pure fission weapons 29:Trinity nuclear test 6137:Aqueous homogeneous 5932:Reprocessed uranium 5605:Safety and security 5182:Smyth, Henry DeWolf 5102:Grace, S. Charles, 4723:on October 9, 2014. 4420:2012JEnvR.109....1R 4376:2011JEnvR.102..672R 4109:2012JEnvR.109....1R 4062:2011JEnvR.102..672R 3568:Nuclear Weapons FAQ 3020:Chain safety method 2898:Savannah River Site 2752:Underground testing 2330: 2080:Pure fusion weapons 2066:pure fusion weapons 1799:Dr. Theodore Taylor 1649:early warning radar 1389:Operation Sandstone 1038:spontaneous fission 913:Li + n → T + He + n 7051:Dense plasma focus 5966:Actinide chemistry 5431:Isotope separation 5328:Nuclear technology 5192:2017-04-21 at the 5140:2015-04-18 at the 5118:2016-12-30 at the 5094:2016-03-03 at the 3918:Cardozo Law Review 3823:Cardozo Law Review 3791:, NNSA March 2007. 3721:Cardozo Law Review 3715:2017-12-12 at the 3659:2021-02-23 at the 3639:2018-02-13 at the 3068:Wire safety method 3017: 2938: 2876:mass spectrometers 2866:The Y-12 plant in 2768: 2745:Daigo Fukuryū Maru 2690: 2616:Starting with the 2611:uranium enrichment 2544:Lawrence Livermore 2516:Able and Baker at 2483:that the proposed 2377:Residual radiation 2328: 2225:Pechora–Kama Canal 2086:Pure fusion weapon 1929:Japanese fishermen 1925:Marshall Islanders 1913: 1858: 1844:Alarm Clock/Sloika 1758: 1675: 1625: 1598: 1545: 1412: 1384: 1287: 1229: 1221: 1204:. Surrounded by a 1182: 1133: 1065:nuclear fratricide 1016:supercritical mass 1012: 884: 761:Tritium production 746: 724: 545:coulomb collisions 522: 33: 7133: 7132: 7083: 7082: 7079: 7078: 7030:Magnetized-target 6927: 6926: 6890: 6889: 6721: 6720: 6717: 6716: 6661: 6660: 6545: 6544: 6477: 6476: 6082: 6081: 6037: 6036: 5906: 5905: 5893:Weapon-free zones 5720: 5719: 5712:Radiopharmacology 5176:978-0-684-82414-7 5158:978-0-684-81378-3 5148:Rhodes, Richard. 5128:978-0-9791915-0-3 4900:. Vol. III. 4752:. July 15, 1999. 4500:978-1-85109-490-5 4347:Sublette, Carey. 4319:. 1 January 2001. 4297:Never say "never" 4025:Operation Redwing 3615:Sublette, Carey. 3495:978-0-521-54117-6 3383:"Atomic Glossary" 3353:Sublette, Carey. 3323:Sublette, Carey. 2961:can also cause a 2929:A diagram of the 2884:Manhattan Project 2857: 2856: 2849: 2730:Nuclear forensics 2644:Explosive testing 2447:Los Alamos Primer 2415:Lawrence Berkeley 2387: 2386: 2366:Instant radiation 2054:Fourth generation 2031:Project Excalibur 1953:Operation Dominic 1945:Operation Redwing 1611:Operation Redwing 1512: 1511: 1504: 1337:plutonium dioxide 1123:Gun-type assembly 1086:neutron generator 1000: 999: 992: 872: 712: 510: 496: 425: 370:Nuclear reactions 367: 366: 131:Nuclear explosion 7163: 7121: 7120: 7109: 7108: 7098: 7097: 7096: 7008: 6967:Levitated dipole 6937: 6929: 6928: 6877:Helium gas (GFR) 6740: 6739: 6735: 6672: 6671: 6556: 6555: 6506: 6505: 6499: 6498: 6494: 6493: 6275: 6274: 6271: 6270: 6109: 6101: 6100: 6093:Nuclear reactors 6088: 6087: 5987:High-level (HLW) 5917: 5916: 5764: 5763: 5744:Food irradiation 5734:Atomic gardening 5627: 5626: 5610:Nuclear meltdown 5436:Nuclear material 5426:Fissile material 5421:Fertile material 5336: 5335: 5321: 5314: 5307: 5298: 5297: 5210: 5061: 5059: 5040: 5034: 5033: 5031: 5000: 4991: 4985: 4982:Warhead Politics 4978: 4972: 4965: 4959: 4958: 4942: 4932: 4926: 4919: 4913: 4912: 4910: 4909: 4888: 4882: 4881: 4879: 4878: 4869:. 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Nuclear Museum 3379: 3373: 3372: 3367: 3365: 3350: 3344: 3343: 3337: 3335: 3320: 3314: 3313: 3311: 3310: 3296: 3290: 3283: 3277: 3270: 3264: 3263: 3261: 3260: 3246: 3240: 3229: 3223: 3221: 3220: 3216: 3205: 3199: 3187: 3181: 3174: 3173: 3172: 3151: 3145: 3137: 3037:One-point safety 2910:nuclear reactors 2852: 2845: 2841: 2838: 2832: 2808: 2807: 2800: 2776:Nevada Test Site 2724:Fallout analysis 2580:multiple warhead 2331: 2327: 2245: 2244: 2243: 2236: 2235: 2215: 2214: 2213: 2206: 2205: 2197: 2196: 2195: 2188: 2187: 2179: 2178: 2177: 2170: 2169: 2014:Third generation 2008:B41 nuclear bomb 1921:Operation Castle 1883:Operation Castle 1872: 1835:Specific designs 1507: 1500: 1496: 1493: 1487: 1456: 1448: 1425:prolate spheroid 1203: 1166:gun-type warhead 1154:tungsten carbide 1151: 1027:severing of the 995: 988: 984: 981: 975: 944: 936: 893: 891: 890: 885: 883: 870: 863: 858: 857: 852: 846: 838: 837: 832: 820: 812: 811: 806: 733: 731: 730: 725: 723: 710: 697: 689: 688: 683: 677: 672: 671: 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4874: 4858: 4854: 4845: 4841: 4835:Wayback Machine 4825: 4821: 4813:Sybil Francis, 4812: 4808: 4801: 4787: 4783: 4773: 4769: 4759: 4757: 4744: 4743: 4739: 4732: 4728: 4713: 4709: 4699: 4697: 4684: 4683: 4679: 4668: 4664: 4655: 4653: 4649: 4642: 4638: 4637: 4633: 4624: 4622: 4618: 4611: 4609:"2013 FOIA Log" 4607: 4606: 4602: 4591: 4587: 4581:Wayback Machine 4572: 4568: 4558: 4556: 4541: 4540: 4533: 4517: 4516: 4510: 4508: 4501: 4485: 4481: 4472: 4470: 4463: 4447: 4443: 4403: 4399: 4360: 4356: 4345: 4341: 4328: 4324: 4315: 4314: 4310: 4304:Wayback Machine 4295: 4291: 4283:physics/0510071 4274: 4270: 4261: 4259: 4252: 4236: 4232: 4223: 4221: 4214: 4200: 4199: 4195: 4186: 4184: 4175: 4174: 4170: 4161: 4159: 4152: 4136: 4132: 4089: 4085: 4042: 4038: 4032:Wayback Machine 4023: 4019: 4013:Wayback Machine 4004: 4000: 3994:Wayback Machine 3985: 3981: 3973: 3969: 3960: 3956: 3948: 3944: 3940:, May 28, 1952. 3938:Wayback Machine 3928: 3924: 3914:Wayback Machine 3905: 3901: 3895:Wayback Machine 3885: 3881: 3875:Wayback Machine 3866: 3862: 3852: 3850: 3833: 3829: 3820:Wayback Machine 3808:Wayback Machine 3799: 3795: 3787: 3783: 3774: 3772: 3759: 3758: 3754: 3744: 3742: 3731: 3727: 3717:Wayback Machine 3707: 3700: 3690: 3686: 3680:Wayback Machine 3671: 3667: 3661:Wayback Machine 3651: 3647: 3641:Wayback Machine 3632: 3628: 3613: 3606: 3600:Wayback Machine 3591: 3587: 3578: 3574: 3566:section of the 3564:Wayback Machine 3555: 3548: 3538: 3536: 3527: 3526: 3522: 3516:Wayback Machine 3507: 3503: 3496: 3482: 3478: 3472: 3468: 3459: 3455: 3450: 3446: 3437: 3430: 3421: 3417: 3407: 3402: 3398: 3388: 3386: 3381: 3380: 3376: 3363: 3361: 3351: 3347: 3333: 3331: 3321: 3317: 3308: 3306: 3298: 3297: 3293: 3284: 3280: 3271: 3267: 3258: 3256: 3248: 3247: 3243: 3230: 3226: 3218: 3206: 3202: 3188: 3184: 3180:50-megatonner." 3170: 3168: 3153: 3152: 3148: 3138: 3134: 3130: 3125: 3108: 3102: 3089: 3083: 3070: 3039: 3022: 3007:Yellow Sun Mk.1 2995: 2971: 2943: 2919: 2853: 2842: 2836: 2833: 2822: 2809: 2805: 2798: 2788:After the 1974 2772:Johnston Island 2760: 2754: 2732: 2726: 2671: 2646: 2552: 2546: 2500:in Washington. 2477: 2471: 2453:production and 2423: 2417: 2408: 2310: 2304: 2256: 2242: 2240: 2239: 2238: 2234: 2232: 2231: 2230: 2229: 2212: 2210: 2209: 2208: 2204: 2202: 2201: 2200: 2199: 2194: 2192: 2191: 2190: 2186: 2184: 2183: 2182: 2181: 2176: 2174: 2173: 2172: 2168: 2166: 2165: 2164: 2163: 2130: 2124: 2118: 2088: 2082: 2056: 2016: 1968:Hardtack Poplar 1899: 1856:, 6.9-megatons. 1846: 1837: 1812: 1756: 1702:H-bomb secret. 1664: 1658: 1534: 1528: 1508: 1497: 1491: 1488: 1473: 1457: 1446: 1405: 1372: 1354:deposited from 1310:metallic phases 1279: 1273: 1256:RaLa Experiment 1175: 1139: 1125: 1057:alpha particles 996: 985: 979: 976: 961: 945: 934: 873: 859: 853: 851: 850: 839: 833: 831: 830: 813: 807: 805: 804: 802: 799: 798: 763: 713: 690: 684: 682: 681: 673: 667: 665: 664: 656: 650: 648: 647: 645: 642: 641: 630: 624: 511: 497: 480: 474: 472: 471: 460: 454: 452: 451: 443: 435: 429: 427: 426: 421: 418: 417: 391: 389:Nuclear fission 385: 372: 363: 314: 294: 284: 253: 108:Nuclear weapons 17: 12: 11: 5: 7169: 7159: 7158: 7153: 7148: 7131: 7130: 7128: 7127: 7115: 7103: 7088: 7085: 7084: 7081: 7080: 7077: 7076: 7074: 7073: 7068: 7063: 7061:Muon-catalyzed 7058: 7053: 7047: 7045: 7041: 7040: 7038: 7037: 7032: 7027: 7022: 7021: 7020: 7010: 7001: 6999: 6993: 6992: 6990: 6989: 6984: 6979: 6974: 6969: 6964: 6958: 6956: 6950: 6949: 6943: 6940: 6939: 6925: 6924: 6922: 6921: 6916: 6915: 6914: 6909: 6898: 6896: 6892: 6891: 6888: 6887: 6885: 6884: 6879: 6874: 6869: 6868: 6867: 6862: 6857: 6852: 6847: 6842: 6837: 6832: 6827: 6822: 6817: 6812: 6801: 6799: 6793: 6792: 6790: 6789: 6784: 6779: 6774: 6769: 6764: 6759: 6754: 6752:Integral (IFR) 6749: 6743: 6737: 6726: 6723: 6722: 6719: 6718: 6715: 6714: 6712: 6711: 6706: 6701: 6696: 6691: 6686: 6680: 6678: 6669: 6663: 6662: 6659: 6658: 6656: 6655: 6654: 6653: 6648: 6647: 6646: 6641: 6636: 6631: 6616: 6611: 6610: 6609: 6598: 6596: 6590: 6589: 6587: 6586: 6581: 6576: 6567: 6565: 6561: 6553: 6547: 6546: 6543: 6542: 6540: 6539: 6534: 6529: 6524: 6518: 6516: 6511: 6503: 6496: 6482: 6479: 6478: 6475: 6474: 6472: 6471: 6470: 6469: 6464: 6459: 6454: 6443: 6441: 6437: 6432: 6431: 6429: 6428: 6422: 6420: 6414: 6413: 6411: 6410: 6405: 6400: 6399: 6398: 6393: 6382: 6380: 6375: 6370: 6369: 6367: 6366: 6365: 6364: 6359: 6354: 6349: 6344: 6343: 6342: 6337: 6332: 6322: 6317: 6316: 6315: 6310: 6307: 6304: 6301: 6287: 6285: 6280: 6272: 6257: 6256: 6254: 6253: 6248: 6247: 6246: 6243: 6238: 6233: 6232: 6231: 6226: 6216: 6211: 6206: 6201: 6196: 6191: 6186: 6181: 6171: 6166: 6165: 6164: 6159: 6154: 6149: 6139: 6133: 6131: 6125: 6124: 6116: 6115: 6112: 6111: 6097: 6096: 6084: 6083: 6080: 6079: 6077: 6076: 6071: 6069:Uranium mining 6066: 6061: 6056: 6051: 6045: 6043: 6039: 6038: 6035: 6034: 6032: 6031: 6026: 6025: 6024: 6019: 6009: 6004: 5999: 5994: 5989: 5984: 5978: 5976: 5972: 5971: 5969: 5968: 5963: 5962: 5961: 5951: 5946: 5945: 5944: 5942:Minor actinide 5939: 5934: 5923: 5921: 5914: 5908: 5907: 5904: 5903: 5901: 5900: 5895: 5890: 5885: 5884: 5883: 5878: 5868: 5862: 5860: 5856: 5855: 5853: 5852: 5851: 5850: 5840: 5835: 5834: 5833: 5828: 5818: 5813: 5808: 5807: 5806: 5796: 5791: 5786: 5781: 5776: 5770: 5768: 5761: 5755: 5754: 5752: 5751: 5746: 5741: 5736: 5730: 5728: 5722: 5721: 5718: 5717: 5715: 5714: 5709: 5704: 5699: 5694: 5689: 5684: 5679: 5673: 5671: 5665: 5664: 5662: 5661: 5656: 5651: 5646: 5641: 5639:Autoradiograph 5635: 5633: 5624: 5618: 5617: 5615: 5614: 5613: 5612: 5602: 5601: 5600: 5590: 5589: 5588: 5578: 5573: 5568: 5563: 5558: 5553: 5547: 5545: 5539: 5538: 5536: 5535: 5530: 5525: 5520: 5515: 5510: 5505: 5500: 5495: 5490: 5485: 5479: 5477: 5471: 5470: 5468: 5467: 5466: 5465: 5460: 5455: 5454: 5453: 5448: 5433: 5428: 5423: 5418: 5413: 5408: 5402: 5400: 5394: 5393: 5391: 5390: 5389: 5388: 5383: 5373: 5368: 5363: 5361:Atomic nucleus 5358: 5353: 5348: 5342: 5340: 5332: 5331: 5324: 5323: 5316: 5309: 5301: 5295: 5294: 5288: 5283: 5273: 5267: 5261: 5256: 5242: 5241: 5240: 5226: 5225:External links 5223: 5203: 5202: 5179: 5161: 5146: 5131: 5106: 5100: 5084: 5081: 5070: 5068: 5065: 5063: 5062: 5055:978-0521054010 5054: 5035: 5009:(3): 261–337. 4986: 4973: 4967:Chuck Hansen, 4960: 4953: 4927: 4914: 4883: 4852: 4846:Chuck Hansen, 4839: 4819: 4806: 4800:978-0520075764 4799: 4781: 4777:New York Times 4767: 4737: 4726: 4707: 4692:. 2013-10-16. 4677: 4662: 4631: 4600: 4585: 4566: 4531: 4499: 4479: 4462:978-9814295918 4461: 4441: 4397: 4370:(7): 672–680. 4354: 4339: 4322: 4308: 4289: 4268: 4251:978-1134901913 4250: 4230: 4213:978-1428922679 4212: 4193: 4168: 4151:978-1134901913 4150: 4130: 4083: 4056:(7): 672–680. 4036: 4017: 3998: 3979: 3967: 3954: 3952:, p. 256. 3942: 3922: 3916:From Morland, 3899: 3879: 3860: 3827: 3801:A 1976 drawing 3793: 3781: 3752: 3725: 3698: 3684: 3665: 3645: 3626: 3604: 3585: 3572: 3546: 3520: 3501: 3494: 3476: 3466: 3453: 3444: 3428: 3415: 3406:, p. 563. 3396: 3374: 3345: 3315: 3291: 3278: 3265: 3254:britannica.com 3241: 3224: 3200: 3182: 3146: 3131: 3129: 3126: 3124: 3121: 3116:access control 3101: 3098: 3082: 3079: 3069: 3066: 3038: 3035: 3021: 3018: 2994: 2991: 2970: 2967: 2957:effect of the 2942: 2939: 2918: 2915: 2906:South Carolina 2855: 2854: 2819:of the subject 2817:worldwide view 2812: 2810: 2803: 2797: 2794: 2756:Main article: 2753: 2750: 2725: 2722: 2698:radiant energy 2670: 2667: 2645: 2642: 2622:indirect drive 2548:Main article: 2545: 2542: 2473:Main article: 2470: 2467: 2419:Main article: 2416: 2413: 2411:by espionage. 2407: 2404: 2385: 2384: 2381: 2378: 2374: 2373: 2370: 2367: 2363: 2362: 2359: 2356: 2355:Thermal energy 2352: 2351: 2348: 2345: 2341: 2340: 2337: 2334: 2306:Main article: 2303: 2300: 2255: 2252: 2246:. As of 2011, 2241: 2233: 2211: 2203: 2193: 2185: 2175: 2167: 2120:Main article: 2117: 2114: 2084:Main article: 2081: 2078: 2055: 2052: 2051: 2050: 2044: 2038: 2028: 2015: 2012: 1972:Redwing Navajo 1898: 1895: 1845: 1842: 1836: 1833: 1823:, might be an 1811: 1808: 1790: 1789: 1785: 1781: 1755: 1754: 1751: 1747: 1740: 1733: 1729: 1696:Stanislaw Ulam 1660:Main article: 1657: 1654: 1591: 1590: 1587: 1584: 1530:Main article: 1527: 1524: 1510: 1509: 1460: 1458: 1451: 1445: 1442: 1433:suitcase nukes 1404: 1401: 1371: 1368: 1341:power reactors 1275:Main article: 1272: 1269: 1254:The series of 1186:Trinity device 1174: 1173:Implosion-type 1171: 1135:Main article: 1124: 1121: 998: 997: 948: 946: 939: 933: 930: 918: 917: 914: 899: 898: 897: 896: 895: 894: 882: 879: 876: 869: 866: 862: 856: 849: 845: 842: 836: 829: 826: 823: 819: 816: 810: 762: 759: 739: 738: 737: 736: 735: 734: 722: 719: 716: 709: 706: 703: 700: 696: 693: 687: 680: 676: 670: 663: 659: 653: 628:Nuclear fusion 626:Main article: 623: 620: 561:mean free path 541:electron volts 537: 536: 535: 534: 533: 532: 520: 517: 514: 507: 504: 500: 493: 490: 486: 483: 477: 470: 466: 463: 457: 450: 446: 442: 438: 432: 387:Main article: 384: 381: 371: 368: 365: 364: 362: 361: 354: 347: 339: 336: 335: 334: 333: 328: 323: 318: 308: 307: 302: 297: 288: 278: 277: 272: 267: 265:United Kingdom 262: 257: 242: 241: 235: 234: 233: 232: 227: 222: 217: 212: 207: 202: 197: 192: 187: 181: 180: 175: 170: 164: 163: 158: 153: 148: 143: 138: 133: 125: 124: 120: 119: 111: 110: 95:hydrogen bombs 80: 79: 65: 57: 40:nuclear weapon 15: 9: 6: 4: 3: 2: 7168: 7157: 7156:Weapon design 7154: 7152: 7149: 7147: 7144: 7143: 7141: 7126: 7125: 7116: 7114: 7113: 7104: 7102: 7101: 7090: 7089: 7086: 7072: 7069: 7067: 7064: 7062: 7059: 7057: 7054: 7052: 7049: 7048: 7046: 7042: 7036: 7033: 7031: 7028: 7026: 7023: 7019: 7018:electrostatic 7016: 7015: 7014: 7011: 7009: 7003: 7002: 7000: 6998: 6994: 6988: 6985: 6983: 6980: 6978: 6975: 6973: 6970: 6968: 6965: 6963: 6960: 6959: 6957: 6955: 6951: 6947: 6941: 6936: 6930: 6920: 6917: 6913: 6910: 6908: 6905: 6904: 6903: 6900: 6899: 6897: 6893: 6883: 6880: 6878: 6875: 6873: 6870: 6866: 6863: 6861: 6858: 6856: 6853: 6851: 6848: 6846: 6843: 6841: 6838: 6836: 6833: 6831: 6828: 6826: 6823: 6821: 6818: 6816: 6813: 6811: 6808: 6807: 6806: 6803: 6802: 6800: 6798: 6797:Generation IV 6794: 6788: 6785: 6783: 6780: 6778: 6775: 6773: 6770: 6768: 6765: 6763: 6760: 6758: 6755: 6753: 6750: 6748: 6747:Breeder (FBR) 6745: 6744: 6741: 6738: 6733: 6724: 6710: 6707: 6705: 6702: 6700: 6697: 6695: 6692: 6690: 6687: 6685: 6682: 6681: 6679: 6677: 6673: 6670: 6668: 6664: 6652: 6649: 6645: 6642: 6640: 6637: 6635: 6632: 6630: 6627: 6626: 6625: 6622: 6621: 6620: 6617: 6615: 6612: 6608: 6605: 6604: 6603: 6600: 6599: 6597: 6595: 6591: 6585: 6582: 6580: 6577: 6575: 6573: 6569: 6568: 6566: 6564: 6557: 6554: 6552: 6548: 6538: 6535: 6533: 6530: 6528: 6525: 6523: 6520: 6519: 6517: 6515: 6507: 6504: 6500: 6497: 6492: 6485: 6480: 6468: 6465: 6463: 6460: 6458: 6455: 6453: 6450: 6449: 6448: 6445: 6444: 6442: 6440: 6433: 6427: 6424: 6423: 6421: 6419: 6415: 6409: 6406: 6404: 6401: 6397: 6394: 6392: 6389: 6388: 6387: 6384: 6383: 6381: 6379: 6371: 6363: 6360: 6358: 6355: 6353: 6350: 6348: 6345: 6341: 6338: 6336: 6333: 6331: 6328: 6327: 6326: 6323: 6321: 6318: 6314: 6311: 6308: 6305: 6302: 6299: 6298: 6297: 6294: 6293: 6292: 6289: 6288: 6286: 6284: 6276: 6273: 6269: 6262: 6258: 6252: 6249: 6244: 6242: 6239: 6237: 6234: 6230: 6227: 6225: 6222: 6221: 6220: 6217: 6215: 6212: 6210: 6207: 6205: 6202: 6200: 6197: 6195: 6192: 6190: 6187: 6185: 6182: 6180: 6177: 6176: 6175: 6172: 6170: 6167: 6163: 6160: 6158: 6155: 6153: 6150: 6148: 6145: 6144: 6143: 6140: 6138: 6135: 6134: 6132: 6130: 6126: 6121: 6120: 6113: 6108: 6102: 6098: 6094: 6089: 6085: 6075: 6072: 6070: 6067: 6065: 6062: 6060: 6057: 6055: 6052: 6050: 6049:Nuclear power 6047: 6046: 6044: 6040: 6030: 6029:Transmutation 6027: 6023: 6020: 6018: 6015: 6014: 6013: 6010: 6008: 6005: 6003: 6000: 5998: 5995: 5993: 5990: 5988: 5985: 5983: 5980: 5979: 5977: 5973: 5967: 5964: 5960: 5957: 5956: 5955: 5952: 5950: 5947: 5943: 5940: 5938: 5935: 5933: 5930: 5929: 5928: 5925: 5924: 5922: 5918: 5915: 5913: 5909: 5899: 5896: 5894: 5891: 5889: 5886: 5882: 5879: 5877: 5874: 5873: 5872: 5869: 5867: 5864: 5863: 5861: 5857: 5849: 5846: 5845: 5844: 5841: 5839: 5836: 5832: 5829: 5827: 5826:high-altitude 5824: 5823: 5822: 5819: 5817: 5816:Proliferation 5814: 5812: 5809: 5805: 5802: 5801: 5800: 5797: 5795: 5792: 5790: 5787: 5785: 5782: 5780: 5777: 5775: 5772: 5771: 5769: 5765: 5762: 5760: 5756: 5750: 5747: 5745: 5742: 5740: 5737: 5735: 5732: 5731: 5729: 5727: 5723: 5713: 5710: 5708: 5705: 5703: 5702:Brachytherapy 5700: 5698: 5695: 5693: 5690: 5688: 5685: 5683: 5680: 5678: 5675: 5674: 5672: 5670: 5666: 5660: 5657: 5655: 5652: 5650: 5647: 5645: 5642: 5640: 5637: 5636: 5634: 5632: 5628: 5625: 5623: 5619: 5611: 5608: 5607: 5606: 5603: 5599: 5596: 5595: 5594: 5591: 5587: 5584: 5583: 5582: 5579: 5577: 5574: 5572: 5569: 5567: 5564: 5562: 5559: 5557: 5554: 5552: 5549: 5548: 5546: 5544: 5540: 5534: 5531: 5529: 5526: 5524: 5521: 5519: 5516: 5514: 5511: 5509: 5506: 5504: 5501: 5499: 5498:Cross section 5496: 5494: 5491: 5489: 5486: 5484: 5481: 5480: 5478: 5476: 5472: 5464: 5461: 5459: 5456: 5452: 5449: 5447: 5444: 5443: 5442: 5439: 5438: 5437: 5434: 5432: 5429: 5427: 5424: 5422: 5419: 5417: 5414: 5412: 5409: 5407: 5404: 5403: 5401: 5399: 5395: 5387: 5384: 5382: 5379: 5378: 5377: 5374: 5372: 5369: 5367: 5364: 5362: 5359: 5357: 5354: 5352: 5349: 5347: 5344: 5343: 5341: 5337: 5333: 5329: 5322: 5317: 5315: 5310: 5308: 5303: 5302: 5299: 5292: 5289: 5287: 5284: 5281: 5277: 5274: 5271: 5268: 5265: 5262: 5260: 5257: 5255: 5251: 5247: 5243: 5239: 5235: 5234: 5232: 5229: 5228: 5222: 5220: 5219: 5214: 5209: 5200: 5196: 5195: 5191: 5188: 5183: 5180: 5177: 5173: 5169: 5165: 5162: 5159: 5155: 5151: 5147: 5144: 5143: 5139: 5136: 5132: 5129: 5125: 5121: 5117: 5114: 5110: 5109:Hansen, Chuck 5107: 5105: 5101: 5098: 5097: 5093: 5090: 5085: 5082: 5079: 5075: 5072: 5071: 5057: 5051: 5047: 5046: 5039: 5028: 5024: 5020: 5016: 5012: 5008: 5004: 4997: 4990: 4983: 4977: 4970: 4964: 4956: 4954:9780684804002 4950: 4946: 4941: 4940: 4931: 4924: 4918: 4903: 4899: 4898: 4893: 4892:Hansen, Chuck 4887: 4872: 4868: 4867: 4862: 4861:Hansen, Chuck 4856: 4849: 4843: 4836: 4832: 4829: 4826:Walter Goad, 4823: 4816: 4810: 4802: 4796: 4792: 4785: 4778: 4771: 4755: 4751: 4747: 4741: 4735: 4730: 4722: 4718: 4711: 4695: 4691: 4687: 4681: 4673: 4666: 4648: 4641: 4635: 4617: 4610: 4604: 4596: 4589: 4582: 4578: 4575: 4570: 4554: 4550: 4549: 4544: 4538: 4536: 4527: 4521: 4506: 4502: 4496: 4492: 4491: 4483: 4468: 4464: 4458: 4454: 4453: 4445: 4437: 4433: 4429: 4425: 4421: 4417: 4413: 4409: 4401: 4393: 4389: 4385: 4381: 4377: 4373: 4369: 4365: 4358: 4350: 4343: 4335: 4334: 4326: 4318: 4312: 4305: 4301: 4298: 4293: 4284: 4279: 4272: 4257: 4253: 4247: 4244:. Routledge. 4243: 4242: 4234: 4219: 4215: 4209: 4205: 4204: 4197: 4182: 4178: 4172: 4157: 4153: 4147: 4144:. Routledge. 4143: 4142: 4134: 4126: 4122: 4118: 4114: 4110: 4106: 4102: 4098: 4094: 4087: 4079: 4075: 4071: 4067: 4063: 4059: 4055: 4051: 4047: 4040: 4033: 4029: 4026: 4021: 4014: 4010: 4007: 4002: 3995: 3991: 3988: 3983: 3977: 3971: 3964: 3958: 3951: 3946: 3939: 3935: 3932: 3926: 3919: 3915: 3911: 3908: 3903: 3896: 3892: 3888: 3883: 3876: 3872: 3869: 3864: 3848: 3844: 3843: 3838: 3831: 3824: 3821: 3817: 3813: 3812:"The Article" 3809: 3805: 3802: 3797: 3790: 3785: 3771:on 2015-04-29 3770: 3766: 3762: 3756: 3740: 3737:. CNBC News. 3736: 3729: 3722: 3718: 3714: 3711: 3710:"Born Secret" 3705: 3703: 3695: 3688: 3681: 3677: 3674: 3669: 3662: 3658: 3655: 3649: 3642: 3638: 3635: 3630: 3622: 3618: 3611: 3609: 3601: 3597: 3594: 3589: 3582: 3576: 3569: 3565: 3561: 3558: 3553: 3551: 3534: 3530: 3524: 3517: 3513: 3510: 3505: 3497: 3491: 3487: 3480: 3470: 3463: 3457: 3448: 3441: 3435: 3433: 3425: 3419: 3411: 3405: 3400: 3384: 3378: 3371: 3360: 3356: 3349: 3342: 3330: 3326: 3319: 3305: 3301: 3295: 3288: 3282: 3275: 3269: 3255: 3251: 3245: 3238: 3234: 3228: 3214: 3210: 3204: 3197: 3193: 3186: 3178: 3166: 3162: 3161: 3156: 3150: 3143: 3136: 3132: 3120: 3117: 3113: 3107: 3097: 3093: 3088: 3078: 3076: 3065: 3062: 3060: 3055: 3051: 3047: 3043: 3034: 3032: 3027: 3014: 3010: 3008: 3004: 3000: 2990: 2987: 2985: 2981: 2975: 2966: 2964: 2960: 2956: 2951: 2949: 2934: 2933: 2927: 2923: 2914: 2911: 2907: 2903: 2899: 2894: 2890: 2887: 2885: 2881: 2877: 2873: 2869: 2864: 2860: 2851: 2848: 2840: 2830: 2826: 2820: 2818: 2811: 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DIANE. 3539:7 October 3364:11 August 3334:11 August 3289:, p. 503. 3209:FR 971324 2880:calutrons 2872:Tennessee 2868:Oak Ridge 2837:June 2014 2829:talk page 2538:Livermore 2520:in 1946. 2339:Enhanced 2160:Cobalt-60 1463:does not 1380:Sandstone 1333:corrosion 1322:trivalent 1303:plutonium 1299:composite 1245:beryllium 1241:aluminium 1081:beryllium 1079:-210 and 951:does not 907:lithium-7 828:⟶ 780:lithium-6 679:⟶ 607:deuterium 449:⟶ 407:xenon-139 220:Terrorism 205:Espionage 200:Blackmail 195:Arms race 7112:Category 7066:Polywell 6997:Inertial 6954:Magnetic 6709:TMSR-LF1 6704:TMSR-500 6684:Fuji MSR 6644:THTR-300 6484:Graphite 6347:PHWR KWU 6313:ACR-1000 6241:IPWR-900 6224:ACPR1000 6219:HPR-1000 6209:CPR-1000 6184:APR-1400 5975:Disposal 5927:Actinide 5920:Products 5779:Delivery 5622:Medicine 5451:depleted 5446:enriched 5416:Helium-3 5381:ionizing 5190:Archived 5138:Archived 5116:Archived 5092:Archived 5027:Archived 4902:Archived 4894:(1995). 4871:Archived 4863:(1995). 4831:Archived 4754:Archived 4750:BBC News 4694:Archived 4647:Archived 4616:Archived 4577:Archived 4553:Archived 4505:Archived 4467:Archived 4436:22541991 4414:: 1–12. 4392:21524834 4300:Archived 4256:Archived 4218:Archived 4181:Archived 4156:Archived 4125:22541991 4103:: 1–12. 4078:21524834 4028:Archived 4009:Archived 3990:Archived 3934:Archived 3910:Archived 3891:Archived 3871:Archived 3847:Archived 3816:Archived 3804:Archived 3739:Archived 3713:Archived 3676:Archived 3657:Archived 3637:Archived 3596:Archived 3560:Archived 3533:Archived 3512:Archived 3442:, p. 21. 3426:, p. 21. 3276:, p. 12. 3165:archived 2941:Gun-type 2874:, where 2823:You may 2590:for the 2485:Thin Man 2336:Standard 2292:Cold War 2286:(LLNL), 2136:'s 1957 2021:Cold War 1919:shot of 1881:shot of 1744:hohlraum 1713:shot of 1671:Ivy Mike 1583:reduced. 1573:Eniwetok 1567:shot of 1364:vanadium 1247:, or an 1188:and the 1077:polonium 1006:Trinity- 784:neutrons 633:energy: 321:Belarus 300:Pakistan 185:Arsenals 156:Delivery 7124:Commons 7035:Z-pinch 7005:Bubble 6987:Tokamak 6850:FBR-600 6830:CFR-600 6825:BN-1200 6491:coolant 6418:Organic 6303:CANDU 9 6300:CANDU 6 6268:coolant 6229:ACP1000 6204:CAP1400 6142:Boiling 6107:Fission 5954:Fission 5898:Weapons 5838:Warfare 5821:Testing 5811:History 5804:effects 5759:Weapons 5669:Therapy 5644:RadBall 5631:Imaging 5523:Thermal 5488:Capture 5475:Neutron 5463:Thorium 5441:Uranium 5406:Tritium 5386:braking 5366:Fission 5356:Physics 5339:Science 5254:effects 5011:Bibcode 4416:Bibcode 4372:Bibcode 4105:Bibcode 4058:Bibcode 3462:Effects 3440:Effects 3424:Effects 3389:24 July 3304:eia.gov 3274:Effects 3026:cadmium 3009:bombs. 2948:cordite 2936:hopper. 2878:called 2556:fizzles 2506:Trinity 2455:capture 2451:neutron 2280:Jupiter 1867:Russian 1852:Castle- 1825:aerogel 1821:Fogbank 1484:removed 1469:sources 1314:gallium 1234:density 1200:Fat Man 1190:Fat Man 1117:inertia 972:removed 957:sources 905:, when 772:in situ 767:tritium 611:tritium 595:fissile 383:Fission 331:Ukraine 173:Workers 168:Effects 151:Testing 141:Warfare 136:History 99:H-bombs 91:A-bombs 68:staged 6935:Fusion 6895:Others 6835:Phénix 6820:BN-800 6815:BN-600 6810:BN-350 6639:HTR-PM 6634:HTR-10 6614:UHTREX 6579:Magnox 6574:(UNGG) 6467:Lucens 6462:KS 150 6199:ATMEA1 6179:AP1000 6162:Kerena 6042:Debate 5794:Ethics 5784:Design 5767:Topics 5598:rocket 5576:Fusion 5571:Policy 5533:Fusion 5493:Poison 5371:Fusion 5174: 5156: 5126: 5052: 4951: 4797: 4497: 4459: 4434: 4390: 4248: 4210: 4148: 4123: 4076: 3492: 3219: 3211:, 3114:is an 2984:Mark 5 2980:Mark 4 2632:. The 2510:Gadget 2489:Pu-240 1887:Bikini 1875:RDS-6s 1871:Слойка 1417:shaper 1352:nickel 1325:metals 1194:Pu-239 1073:Urchin 1008:Gadget 871: 788:helium 711: 622:Fusion 566:plasma 553:tamper 509: 495: 424: 405:(Sr), 312:Former 293: 291:Israel 282:Others 270:France 260:Russia 230:Winter 178:Ethics 146:Design 25:Gadget 7056:Migma 7044:Other 7013:Fusor 6912:Piqua 6907:Arbus 6865:PRISM 6607:MHR-T 6602:GTMHR 6532:EGP-6 6527:AMB-X 6502:Water 6447:HWGCR 6386:HWLWR 6325:IPHWR 6296:CANDU 6157:ESBWR 5912:Waste 5876:Tests 5859:Lists 5843:Yield 5586:MMRTG 5543:Power 5030:(PDF) 4999:(PDF) 4650:(PDF) 4643:(PDF) 4619:(PDF) 4612:(PDF) 4278:arXiv 3192:Joe 4 3128:Notes 3075:boron 2959:water 2902:Aiken 2596:Atlas 2592:Titan 2344:Blast 2221:salvo 2138:novel 1983:Taiga 1854:Union 1301:with 1295:U-235 1249:alloy 1237:metal 1206:U-238 1198:(see 1146:(see 286:India 275:China 161:Yield 51:Japan 6872:Lead 6855:CEFR 6845:PFBR 6727:None 6537:RBMK 6522:AM-1 6452:EL-4 6426:WR-1 6408:AHWR 6352:MZFR 6320:CVTR 6309:AFCR 6236:VVER 6194:APWR 6189:APR+ 6152:ABWR 6022:cask 6017:pool 5959:LLFP 5848:TNTe 5528:Fast 5398:Fuel 5244:The 5172:ISBN 5154:ISBN 5124:ISBN 5050:ISBN 4949:ISBN 4795:ISBN 4762:2010 4702:2014 4548:IERI 4526:link 4495:ISBN 4457:ISBN 4432:PMID 4388:PMID 4246:ISBN 4208:ISBN 4146:ISBN 4121:PMID 4074:PMID 3961:See 3855:2016 3747:2017 3541:2014 3490:ISBN 3410:help 3391:2023 3366:2021 3336:2021 3160:Life 3005:and 2982:and 2896:The 2781:The 2618:Nova 2372:30% 2361:25% 2350:40% 1927:and 1711:Mike 1694:and 1604:Swan 1565:Item 1541:Item 1467:any 1465:cite 1378:The 1360:gold 1339:for 1094:ions 955:any 953:cite 708:17.6 609:and 557:heat 551:and 6944:by 6860:PFR 6651:PMR 6629:AVR 6551:Gas 6489:by 6457:KKN 6391:ATR 6306:EC6 6266:by 6214:EPR 6147:BWR 5111:, " 5019:doi 4945:541 4424:doi 4412:109 4380:doi 4368:102 4113:doi 4101:109 4066:doi 4054:102 3963:map 3142:W80 3059:W47 2900:in 2638:NIF 2600:W54 2400:W88 2398:or 2396:W87 2383:5% 2380:10% 2358:35% 2347:50% 1630:W54 1478:by 1437:W48 1291:pit 966:by 549:pit 506:180 476:139 431:235 249:NPT 97:or 53:in 7142:: 6594:He 6560:CO 6436:CO 6357:R3 5184:, 5166:. 5076:, 5048:. 5025:. 5017:. 5005:. 5001:. 4947:. 4748:. 4688:. 4645:. 4614:. 4551:. 4545:. 4534:^ 4522:}} 4518:{{ 4503:. 4465:. 4430:. 4422:. 4410:. 4386:. 4378:. 4366:. 4254:. 4216:. 4154:. 4119:. 4111:. 4099:. 4095:. 4072:. 4064:. 4052:. 4048:. 3889:, 3845:. 3839:. 3814:, 3763:. 3719:, 3701:^ 3619:. 3607:^ 3549:^ 3531:. 3431:^ 3368:. 3357:. 3338:. 3327:. 3302:. 3252:. 3157:, 3110:A 2904:, 2870:, 2702:Li 2640:. 2461:, 2457:, 2402:. 2369:5% 2237:Co 2207:Co 2189:Co 2171:Co 1869:: 1571:, 1243:, 1067:. 1023:. 456:95 6734:) 6730:( 6562:2 6514:O 6512:2 6510:H 6438:2 6378:O 6376:2 6374:H 6283:O 6281:2 6279:D 5320:e 5313:t 5306:v 5201:) 5178:) 5160:) 5060:. 5058:. 5021:: 5013:: 5007:4 4957:. 4911:. 4880:. 4803:. 4764:. 4704:. 4659:. 4628:. 4597:. 4583:. 4564:. 4562:. 4528:) 4514:. 4476:. 4438:. 4426:: 4418:: 4394:. 4382:: 4374:: 4351:. 4286:. 4280:: 4265:. 4227:. 4190:. 4165:. 4127:. 4115:: 4107:: 4080:. 4068:: 4060:: 3974:{ 3965:. 3857:. 3778:. 3749:. 3623:. 3543:. 3498:. 3412:) 3393:. 3312:. 3262:. 3222:. 3144:. 2850:) 2844:( 2839:) 2835:( 2821:. 2162:( 2037:. 1865:( 1739:. 1505:) 1499:( 1494:) 1490:( 1486:. 1472:. 1071:" 993:) 987:( 982:) 978:( 974:. 960:. 881:V 878:e 875:M 868:5 865:+ 861:T 855:3 848:+ 844:e 841:H 835:4 825:n 822:+ 818:i 815:L 809:6 721:V 718:e 715:M 705:+ 702:n 699:+ 695:e 692:H 686:4 675:T 669:3 662:+ 658:D 652:2 519:V 516:e 513:M 503:+ 499:n 492:2 489:+ 485:e 482:X 469:+ 465:r 462:S 445:n 441:+ 437:U 358:e 351:t 344:v 31:.

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Nuclear weapon design

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