A nuclear weapon is a weapon that derives its energy from nuclear reactions and has enormous
destructive power—even the smallest nuclear weapons are much more powerful than most conventional explosives, while the
largest can destroy entire metropolitan regions. Nuclear weapons have been used twice for war, when the United States dropped two such bombs on the Japanese cities of Hiroshima and Nagasaki during World War II. They have been used around 2000 times since then, but only for the nuclear testing undertaken by seven countries (U.S., Soviet Union, France, United Kingdom, China, India,
and Pakistan).
The declared nuclear powers are, the United States, Russia, the United Kingdom,
France, the People's Republic of China, India and Pakistan. In addition, Israel almost
certainly has nuclear weapons, though it refuses to publicly state whether it possesses them or not (see Israel and weapons of mass
destruction). North Korea has stated recently that it has nuclear
weapons; Ukraine may possess a nuclear stockpile due to a clerical error; and
Iran is allegedly developing the capacity to produce its own nuclear arsenal. See the
list of countries with
nuclear weapons for more details.
Non-weaponized nuclear explosives have also been proposed for
various civilian uses.
Types of weapons
- For more technical details see: Nuclear weapon
design
Common types
Fission bombs
Fission bombs derive their power from nuclear fission,
where heavy nuclei (uranium or plutonium) split into lighter elements when bombarded by neutrons
(producing more neutrons which bombard other nuclei, triggering a
nuclear chain reaction). These are historically called
atom bombs or A-bombs, though this name is not precise due to the fact that chemical reactions release energy from
atomic bonds too, and fusion is no less atomic than fission. Despite this possible confusion, the term atom bomb has still
been generally accepted to refer specifically to nuclear weapons, and most commonly to pure fission devices.
In general, fission bombs are powered by using chemical explosives to compress a sub-critical amount of either uranium-235 or plutonium into a dense, super-critical mass, which is then subjected to a source of
neutrons. This begins an uncontrollable nuclear chain reaction, and produces a very large amount of energy.
One pound of U-235 can release over 37 million million joules of energy. This is 82 terajoules per kilogram (TJ/kg). A typical
duration of the chain reaction is 1 μs, so the power is 82 EW/kg (30 μW or 200
MeV/s per atom; related to the duration of one generation of the chain reaction: 3mW/atom,
i.e., the power of a chain reaction just at criticality is 3mW in the case of consecutive fissions, one at a time).
Fusion bombs
Fusion bombs are based on nuclear fusion where light nuclei
such as hydrogen and helium combine
together into heavier elements and release large amounts of energy. Weapons which have a fusion stage are also referred to as
hydrogen bombs or H-bombs because their fusion fuel is often a form of hydrogen, or thermonuclear weapons
because fusion reactions require extremely high temperatures for a chain
reaction to occur. This latter name can be somewhat confusing, as thermonuclear reactions can take place in nuclear weapons
which are not considered "true" fusion bombs (the United States' George test of 1951
was one such device, the Soviet Union's Joe 4 device was another, both of which
were fission bombs utilizing some fusion fuel to increase their yield).
Generally speaking, hydrogen bombs work by having a "primary" device (a fission bomb) detonate and begin the fusion reactions
in the "secondary" device (fusion fuel). A virtually limitless number of large "secondaries" can be chained together (each fusion
reaction beginning the next) in this fashion, creating weapons with far larger yields than could be achieved with simple fission
alone.
Dirty bombs
Dirty bomb is now a term for a radiological weapon, a non-nuclear bomb that disperses radioactive material that was packed in with the
bomb. When the bomb explodes, the scattering of this radioactive material causes radioactive contamination, a health hazard similar to that of nuclear fallout. One of the most publicly stated fears of Western governments since the September 11, 2001 attacks has been the terrorist
detonation of a dirty bomb in a populated area. Dirty bombs, similar to other
enhanced fallout weapons of more technologically sophisticated design, are area denial weapons that can potentially render an area unfit for habitation for years or decades after
the detonation. In the estimation of most analysts, though, the effect would be primarily psychological, and potentially economic
if a costly clean-up effort was called for.
Nomenclature
Nuclear weapons are often described as either fission or fusion devices based on the dominant source of the weapon's energy. The
distinction between these two types of weapon is blurred by the fact that they are combined in nearly all complex modern weapons:
a smaller fission bomb is first used to reach the necessary conditions of high temperature and pressure to allow fusion to occur. On the other
hand, a fission device is more efficient when a fusion core first boosts the weapon's energy. Finally, a fusion weapon may
include a fission core (in addition to being externally compressed by fission explosion) in order to achieve more complete fusion
(see nuclear weapon design for some description of all
these variants). Since the distinguishing feature of both fission and fusion weapons is that they release energy from
transformations of the atomic nucleus, the most accurate general term for all types of these explosive devices is "nuclear
weapon."
Advanced thermonuclear weapons designs
The most powerful modern weapons include a fissionable outer shell of uranium. The
intense fast neutrons from the fusion stage of the weapon will cause natural (that is unenriched) uranium to fission, increasing the yield of the weapon many times.
Cobalt bombs
The cobalt bomb uses cobalt in the shell, and the fusion neutrons convert the
cobalt into cobalt-60, a powerful long-term (5 years) emitter of gamma rays. In
general this type of weapon is referred to as a salted bomb and variable fallout effects can be obtained by using
different salting isotopes. Gold has been
proposed for short-term fallout (days), tantalum and zinc for fallout of intermediate duration (months), and cobalt for long term
contamination (years). The primary purpose of this weapon is to create
excess radioactive fallout making a large region uninhabitable. No
cobalt or other salted bomb has been built or tested publicly.
Neutron bombs
A final variant of the thermonuclear weapons is the enhanced radiation weapon, or neutron bomb, which is a small thermonuclear weapon in which the burst of neutrons generated by the
fusion reaction is intentionally not absorbed inside the weapon, but allowed to escape. The X-ray mirrors and shell of the weapon are made of chromium or nickel so that the neutrons are permitted to escape. This intense burst of high-energy neutrons
is a highly destructive mechanism, although the bomb will still produce damaging thermal and shock effects, only with a lower
magnitude than a standard thermonuclear weapon. Neutrons are more penetrating than other types of radiation so many shielding
materials that work well against gamma rays are less effective against
neutrons. They are also more biologically harmful than gamma rays, and this knowledge led some to envision a weapon that would do
little physical damage while killing all the people in a certain area (a so-called "landlord bomb"). This appears to be somewhat
of an exaggeration, as the bomb would still create at least some significant blast and fire damage. The term "enhanced radiation"
refers only to the burst of ionizing radiation released at the moment of detonation, not to any enhancement of residual radiation
in fallout (as in the salted bombs discussed above).
Antimatter bombs
Some of these hypothetical devices would not literally be nuclear weapons because they do not involve the energy derived from
altering the nucleus of an atom either by fission or fusion reactions. They also are not dependent upon a chain reaction of
neutron emission. But as these would generate much greater blast per weight than do conventional explosives, and would also
radiate gamma rays as do nuclear weapons, often they are lumped together with the
latter. Antiprotons or antineutrons striking the nuclei of matter atoms could also cause secondary nuclear reactions by
annihilating protons or neutrons.
There has been some speculation as to the use of antimatter as the source
for a weapon of some sort. Antimatter reactions give off more energy even than fusion reactions, and, it is imagined, would
produce neither radioactive nuclear fallout nor neutron radiation. Further, unlike nuclear weapons, there would be no minimum
size. There have been indications that the U.S. Air Force has pursued
research in this direction, but as there are as of yet no technologies for production and storage of antimatter in sufficient
quantities, the whole affair is viewed by many with considerable scepticism. See antimatter weapon for more information.
Effects of a nuclear explosion
The energy released from a nuclear weapon comes in four primary categories:
- Blast—40-60% of total energy
- Thermal radiation—30-50% of total energy
- Ionizing radiation—5% of total energy
- Residual radiation (fallout)—5-10% of total energy
The amount of energy released in each form depends on the design of the weapon, and the environment in which it is detonated.
The residual radiation of fallout is a delayed release of energy,
while the other three forms of energy release are immediate.
The dominant effects of a nuclear weapon (the blast and thermal radiation) are the same physical damage mechanisms as
conventional explosives. The primary difference is that nuclear weapons are
capable of releasing much larger amounts of energy at once. Most of the damage caused by a nuclear weapon is not directly related
to the nuclear process of energy release, but would be present for any explosion of the same magnitude.
The damage done by each of the three initial forms of energy release differs with the size of the weapon. Thermal radiation
drops off the slowest with distance, so the larger the weapon the more important this effect becomes. Ionizing radiation is
strongly absorbed by air, so it is only dangerous by itself for smaller weapons. Blast damage falls off more quickly than thermal
radiation but more slowly than ionizing radiation.
When a nuclear weapon explodes, the bomb's material comes to an equilibrium temperature in about a microsecond. At this
time about 75% of the energy is emitted as primary thermal radiation, mostly soft X-rays.
Almost all of the rest of the energy is kinetic energy in
rapidly-moving weapon debris. The interaction of the x-rays and debris with the surroundings determines how much energy is
produced as blast and how much as light. In general, the denser the medium around the bomb, the more it will absorb, and the more
powerful the shockwave will be.
When a nuclear detonation occurs in air near sea-level, most of the soft X-rays in the primary thermal radiation are absorbed within a few feet. Some energy is re-radiated in the ultraviolet, visible light and infrared, but most of the energy heats a spherical volume of air. This forms the fireball.
In a burst at high altitudes, where the air density is low, the soft X-rays travel long distances before they are absorbed.
The energy is so diluted that the blast
wave may be half as strong or less. The rest of the energy is dissipated as a more powerful thermal pulse.
In 1945 there was some initial speculation among the scientists developing the first nuclear weapons that there might be a
possibility of igniting the earth's atmosphere with a large enough nuclear
explosion. This was, however, quickly shown to be mathematically unlikely enough to be considered impossible, though the notion
has persisted as a rumor for many years.
Yield
The explosive yield of a nuclear weapon is expressed in the equivalent mass of trinitrotoluene (TNT), either in kilotons (thousands of tons of
TNT) or megatons (million of tons of TNT). Examples of nuclear weapon yields:
- Davy Crockett tactical nuclear
weapon: variable yield 0.01-1 kt — mass only 23 kg (51 lb), lightest ever deployed by the United States (same warhead as
Special Atomic Demolition
Munition and GAR-11 Nuclear Falcon missile)
- Hiroshima's "Little Boy": 12-15 kt — gun type uranium-235 fission
bomb (the first of the only two nuclear weapons that have ever been used in warfare)
- Nagasaki's "Fat Man": 20-22 kt — implosion type plutonium-239 fission bomb
(the second of the two nuclear weapons used in warfare)
- W-76 warhead 100 kt (10 of these may be in a MIRVed Trident II missile)
- B-61 Mod 3 gravity bomb: 4 yield options ("dial-a-yield"): 0.3 kt, 1.5 kt, 60 kt, and 170 kt
- W-87 warhead: 300 kt (10 of these are in a MIRVed LG-118A Peacekeeper)
- W-88 warhead: 475 kt (8 of these may be in a Trident II missile)
- Castle Bravo device: 15 Mt — largest tested by the US
- EC17/Mk-17, the EC24/Mk-24, and the B41 (Mk41) (largest nuclear weapons ever built by the United States): 25 Mt —
gravity bombs carried by B-36 bomber (retired by 1957)
- Tsar Bomba device: 50 Mt — USSR, largest yield explosive device ever,
mass of 27 short tons (24 metric tons), in its "full" form it would have been 100 Mt
As a comparison, the Oklahoma City bombing, using a
truck-based fertilizer bomb, was a mere 0.002 kt.
The "yield per ton", the amount of weapons yield compared to the mass of the weapon, is for current US weapons 600 kt/t (2.5
TJ/kg) to 2.2 Mt/t (9.2 TJ/kg). By comparison, for the Davy Crockett it was 40 kt/t (0.167 TJ/kg) and for the Tsar Bomba it was 2
Mt/t (8 TJ/kg).
Blast damage
Much of the destruction caused by a nuclear explosion is due
to blast effects. Most buildings, except reinforced or blast-resistant structures, will suffer moderate to severe damage when
subjected to moderate overpressures. The blast wind may exceed several hundred kilometers per hour. The range for blast effects
increases with the explosive yield of the weapon.
Two distinct, simultaneous phenomena are associated with the blast wave in air:
- Static overpressure, i.e., the sharp increase in pressure exerted by the
shock wave. The overpressure at any given point is directly proportional to the density of the air in the wave.
- Dynamic pressures, i.e., drag exerted by the blast winds required to form the blast wave. These winds push, tumble and
tear objects.
Most of the material damage caused by a nuclear air burst is caused by a
combination of the high static overpressures and the blast winds. The long compression of the blast wave weakens structures,
which are then torn apart by the blast winds. The compression, vacuum and drag phases together may last several seconds or
longer, and exert forces many times greater than the strongest hurricane.
Thermal radiation
Nuclear weapons emit large amounts of electromagnetic radiation as visible, infrared, and
ultraviolet light. The chief hazards are burns and eye injuries. On clear
days, these injuries can occur well beyond blast ranges. The light is so powerful that it can start fires that spread rapidly in
the debris left by a blast. The range of thermal effects increases markedly with weapon yield.
Since thermal radiation travels in straight lines from the
fireball (unless scattered) any opaque object will produce a protective shadow. If
fog or haze scatters the light, it will heat things from all directions and shielding will be less effective.
When thermal radiation strikes an object, part will be reflected, part transmitted, and the rest absorbed. The fraction that
is absorbed depends on the nature and color of the material. A thin material may transmit a lot. A light colored object may
reflect much of the incident radiation and thus escape damage. The absorbed thermal radiation raises the temperature of the
surface and results in scorching, charring, and burning of wood, paper, fabrics, etc. If the material is a poor thermal
conductor, the heat is confined to the surface of the material.
Actual ignition of materials depends on how long the thermal pulse lasts and the thickness and moisture content of the target.
Near ground zero where the light is most intense, what can burn, will. Farther away, only the most easily ignited materials will
flame. Incendiary effects are compounded by secondary fires started by the blast wave effects such as from upset stoves and
furnaces.
In Hiroshima, a tremendous fire
storm developed within 20 minutes after detonation. A fire storm has gale force winds blowing in towards the center of the
fire from all points of the compass. It is not, however, a phenomenon peculiar to nuclear explosions, having been observed
frequently in large forest fires and following incendiary raids during World
War II.
Gamma rays from a nuclear explosion produce high energy electrons through
Compton scattering. These electrons are captured in the earth's
magnetic field, at altitudes between twenty and forty kilometers, where they resonate. The oscillating electric current produces
a coherent EMP (electromagnetic pulse) which lasts about 1 millisecond. Secondary effects may last for more than a second.
The pulse is powerful enough so that long metal objects (such as cables) act as antennas and generate high voltages when the pulse passes. These voltages, and the associated high currents, can destroy unshielded electronics and even many
wires. There are no known biological effects of EMP. The ionized air also disrupts radio traffic that would normally bounce off
the ionosphere.
One can shield electronics by wrapping them completely in conductive mesh, or any other form of Faraday
cage. Of course radios cannot operate when shielded, because broadcast radio waves can't reach them.
The largest-yield nuclear devices are designed for this use. An air burst at the right altitude could produce continent-wide
effects.
About 5% of the energy released in a nuclear air burst is in the form of neutrons, gamma rays, alpha particles, and electrons
moving at incredible speeds. The neutrons result almost exclusively from the fission and fusion reactions, while the initial
gamma radiation includes that arising from these reactions as well as that resulting from the decay of short-lived fission
products.
The intensity of initial nuclear radiation decreases rapidly with distance from the point of burst because the radiation
spreads over a larger area as it travels away from the explosion. It is also reduced by atmospheric absorption and
scattering.
The character of the radiation received at a given location also varies with distance from the explosion. Near the point of
the explosion, the neutron intensity is greater than the gamma intensity, but with increasing distance the neutron-gamma ratio
decreases. Ultimately, the neutron component of initial radiation becomes negligible in comparison with the gamma component. The
range for significant levels of initial radiation does not increase markedly with weapon yield and, as a result, the initial
radiation becomes less of a hazard with increasing yield. With larger weapons, above 50 kt (200 TJ), blast and thermal effects
are so much greater in importance that prompt radiation effects can be ignored.
The neutron radiation serves to transmute the surrounding matter, often rendering it radioactive. When added to the dust of
radioactive material released by the bomb itself, a large amount of radioactive material is released into the environment. This
form of radioactive contamination is known as
nuclear fallout and poses the primary risk of exposure to ionizing
radiation for a large nuclear weapon.
The residual radioactive contamination hazard
from a nuclear explosion is in the form of radioactive fallout and neutron-induced activity. Residual ionizing radiation arises
from:
- Fission products. These are intermediate weight isotopes which are formed when a heavy uranium or plutonium nucleus is
split in a fission reaction. There are over 300 different fission products that may result from a fission reaction. Many of these
are radioactive with widely differing half-lives. Some are very short, i.e., fractions of a second, while a few are long enough
that the materials can be a hazard for months or years. Their principal mode of decay is by the emission of beta and gamma
radiation. Approximately 60 grams of fission products are formed per kiloton of yield (14 g/TJ). The estimated activity of this
quantity of fission products 1 minute after detonation is equal to that of 1.1 × 1021 Bq (30 gigagrams of
radium) in equilibrium with its decay products.
- Unfissioned nuclear material. Nuclear weapons are relatively inefficient in their use of fissionable material, and
much of the uranium and plutonium is dispersed by the explosion without undergoing fission. Such unfissioned nuclear material
decays slowly by the emission of alpha particles and is of relatively minor importance.
- Neutron-induced activity. If atomic nuclei capture neutrons when exposed to a flux of neutron radiation, they will, as
a rule, become radioactive (neutron-induced activity) and then decay by emission of beta and gamma radiation over an extended
period. Neutrons emitted as part of the initial nuclear radiation will cause activation of the weapon residues. In addition,
atoms of environmental material, such as soil, air, and water, may be activated, depending on their composition and distance from
the burst. For example, a small area around ground zero may become hazardous as a result of exposure of the minerals in the soil
to initial neutron radiation. This is due principally to neutron capture by various elements, such as sodium, manganese, aluminum and silicon in the soil. This is a negligible hazard because
of the limited area involved.
In an explosion near the surface large amounts of earth or water will be vaporized by the heat of the fireball and drawn up
into the radioactive cloud. This material will become radioactive when it condenses, mixed with fission products and other
radiocontaminants that have become neutron-activated. The larger particles will settle back to the earth's surface near ground
zero (depending on wind and weather conditions of course) within 24 hours, while fine particles will rise to the stratosphere and
be distributed globally over the course of weeks or months.
Severe local fallout contamination can extend far beyond the blast and thermal effects, particularly in the case of high yield
surface detonations. In detonations near a water surface, the particles tend to be lighter and smaller and produce less local
fallout but will extend over a greater area. The particles contain mostly sea salts with some water; these can have a cloud
seeding effect causing local rainout and areas of high local fallout.
The radiobiological hazard of worldwide fallout is essentially a long-term one due to the potential accumulation of long-lived
radioisotopes, such as strontium-90 and caesium-137, in the body as a result of ingestion of foods incorporating these radioactive materials. Chemically,
both isotopes are recognized as similar to calcium and deposited in bone structure throughout the body. These highly-radioactive
substances then interfere with white blood cell production, which is a prime effect of radiation sickness. The hazard of
worldwide fallout is much less serious than the hazards which are associated with local fallout.
Blast and thermal injuries in many cases will far outnumber radiation injuries. However, radiation effects are considerably
more complex and varied than are blast or thermal effects and are subject to considerable misunderstanding. A wide range of
biological changes may follow the irradiation of animals, ranging from rapid death following high doses of penetrating whole-body
radiation to essentially normal lives for a variable period of time until the development of delayed radiation effects, in a
portion of the exposed population, following low dose exposures.
For more technical details see: nuclear explosion.
Weapons delivery
The term strategic nuclear weapons is generally used to denote large weapons which would be used to destroy large
targets, such as cities. Tactical nuclear weapons are smaller weapons used to destroy specific military, communications,
or infrastructure targets. By modern standards, the bombs that destroyed Hiroshima and Nagasaki in 1945 may perhaps be considered tactical weapons (with yields between 13 and 22 kilotons (54 to 92 TJ)), although
modern tactical weapons are considerably lighter and more compact.
Basic methods of delivery for nuclear weapons are:
No nuclear weapon qualifies as a "wooden bomb" - US slang for one trouble-free, maintenance-free, and danger-free under all
conditions. This method of delivery requires that the weapon be capable of withstanding vibrations and changes in air temperature
and pressure during the course of a flight. Early weapons often had a removable core for safety, installed by the air crew during
flight. Also, they had to meet safety conditions were they dropped accidentally. And they had to have a fuze of a variety of
types for detonation. US nuclear weapons that met these criteria are designated by the letter "B" followed, without a hyphen, by
the sequential number of the "physics package" it contains. The
B61, for example, was the main such bomb in the US arsenal for decades.
Various air-dropping techniques exist, including toss bombing, parachute-retarded delivery, and laydown
modes, intended to give the dropping aircraft time to escape the ensuing blast.
The first weapons could only be carried by the B-29. Early
weapons were so big and heavy that they could only be carried by bombers such as the
B-52 and V
bombers, but by the mid-1950s smaller weapons had been developed that could be
carried and deployed by fighter-bombers.
Missiles using a ballistic
trajectory usually deliver a warhead over the horizon. Mobile ballistic missiles may
have a range of tens to hundreds of kilometers, while larger ICBMs or SLBMs may use suborbital or partial orbital trajectories for intercontinental range. Early ballistic missiles
carried a single warhead, often of megaton-range yield. Since the 1970s modern ballistic weapons often use multiple independent reentry vehicles (MIRVs) with up to a dozen warheads, usually of kiloton-range yield. This allows a single launched missile to strike a handful of targets, or
inflict maximum damage on a single target by encircling the target with warheads.
Missile warheads in the American arsenal are indicated by the letter "W"; e.g., W61 would have the same physics package as the B61 above, but it would have different environmental
requirements, and, as it would not be crew-tended after launch but remain atop a missile for a great length of time, different
safety requirements.
A jet engine or rocket-propelled
missile that flies at low altitude using an automated guidance system (usually
inertial navigation, sometimes supplemented by either
GPS or mid-course updates from friendly forces) to make them harder to detect or intercept could carry a
nuclear warhead. Cruise missiles have shorter range and smaller payloads than ballistic missiles, so their warheads are smaller
and less powerful. Rather than multiple warheads, which would have to be dropped separately as though the cruise missile were
itself a bomber, each cruise missile carries its own warhead, although the B-1
Lancer bomber was designed to carry in its bomb-bay a rotating fixture for cruise missiles which resembles a set of MIRV
warheads. Conventional cruise missiles sometimes use cluster
munition payloads, though. Cruise missiles may be launched from mobile launchers on the ground, from naval ships, or from
aircraft.
There is no letter change in the US arsenal to distinguish the warheads of cruise missiles from those for ballistic
missiles.
Other delivery systems
Other potential delivery methods include artillery shells,
mines such as Blue Peacock, and nuclear depth charges and torpedoes for anti-submarine warfare. An atomic mortar was also tested. In the 1950s the U.S. developed small nuclear warheads for air defense use, such as the Nike Hercules. Further developments of this concept, some with much larger
warheads, showed promise as anti-ballistic missiles.
Most of the United States' nuclear air-defense weapons were out of service by the end of the 1960s, and nuclear depth bombs were taken out of service by 1990. However, the
USSR (and later Russia) continues to maintain anti-ballistic missiles with nuclear warheads. Small, two-man portable tactical
weapons ("erroneously referred to as suitcase bombs"), such as the
Special Atomic Demolition
Munition, have been developed, although the difficulty of balancing yield and portability limits their military utility.
See list of nuclear weapons for a list of the
designs of nuclear weapons fielded by the various nuclear powers.
Related topics
- More Technical Details
- History
- Related Technology and Science
- Military strategy
- Proliferation and Politics
- Popular Culture
References
- Glasstone, Samuel and Dolan, Philip J., The Effects of Nuclear Weapons (third edition) (http://www.cddc.vt.edu/host/atomic/nukeffct/), U.S. Government Printing Office, 1977.
PDF Version (http://www.princeton.edu/~globsec/publications/effects/effects.shtml)
- NATO Handbook on the Medical Aspects of NBC Defensive Operations
(Part I - Nuclear) (http://www.fas.org/nuke/guide/usa/doctrine/dod/fm8-9/1toc.htm), Departments of the Army,
Navy, and Air Force, Washington, D.C., 1996.
- Hansen, Chuck. U.S. Nuclear Weapons: The Secret History, Arlington, TX: Aerofax, 1988.
- Hansen, Chuck. The Swords of Armageddon: U.S. nuclear weapons development since 1945, Sunnyvale, CA: Chukelea
Publications, 1995 [1] (http://www.uscoldwar.com/).
- Smyth, Henry DeWolf. Atomic Energy for
Military Purposes (http://nuclearweaponarchive.org/Smyth/), Princeton
University Press, 1945. (The first declassified report by the US government on nuclear weapons) (Smyth Report)
- The Effects of Nuclear War (http://www.fas.org/nuke/intro/nuke/7906/index.html), Office of Technology Assessment (May
1979).
- Rhodes, Richard. Dark Sun: The Making of the Hydrogen Bomb. Simon and Schuster, New York, (1995 ISBN 0684824140)
- Rhodes, Richard. The Making of the Atomic Bomb. Simon and Schuster, New York, (1986 ISBN 0684813785)
- Weart, Spencer R. Nuclear Fear: A History of Images. Cambridge, Mass.: Harvard University Press, 1988.
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