Project 596, (Miss Qiu (Chinese: 邱小姐 , Qiū Xiǎojiě) as code word,  Chic-1 by the US intelligence agencies  ) was the first nuclear weapons test conducted by the People's Republic of China, detonated on 16 October 1964, at the Lop Nur test site. It was a uranium-235 implosion fission device made from weapons-grade uranium (U-235) enriched in a gaseous diffusion plant in Lanzhou. 
The atomic bomb was a part of China's "Two Bombs, One Satellite" program. It had a yield of 22 kilotons, comparable to the Soviet Union's first nuclear bomb RDS-1 in 1949 and the American Fat Man bomb dropped on Nagasaki, Japan in 1945.  With the test, China became the fifth nuclear power in the world. This was the first of 45 successful nuclear tests China conducted between 1964 and 1996, all of which occurred at the Lop Nur test site. 
Korean War FAQ
Copyright(C) Dongxiao Yue , 1998, All rights reserved.
31 . What did Mao say about US after the Korean war?
"American imperialists are very arrogant, they are very unreasonable whenever they can get away with it, if they became a little bit reasonable, it was because they had no other choice."
32 . Did US consider the use the A-Bomb in Korea?
US generals actively considered the use of Atomic Bombs from the very beginning, even before China intervened. US presidents considered the use of the A-Bombs after PVA entered.
On June 1950, Eisenhower met with Collins, Haislip, Ridgway, Ike suggested use of two atomic bombs in the Korea area.
In July 1950, MacArthur suggested plan to use atomic bombs to 'isolate the battle fields".
On November 30 1950, President Truman said in a press conference: "There had always been active consideration of its[Atomic Bomb's] use. ".
On December 24 1950, MacArthur submitted a list of 'retaliation targets' in China and North Korea, requiring 26 atomic bombs.
In January 1953, US tested its first tactical nuclear weapon, and the JCS considered its use "against military targets affecting operations in Korea."
In February 1953, in a NSC meeting, President Eisenhower suggested the Kaesong area of North Korea as an appropriate demonstration ground for a tactical nuclear bomb--it "provided a good target for this type of weapon".
On May 19 1953, the Joint Chiefs recommended direct air and naval operations against China, including the use of nuclear weapons. The National Security Council endorsed the JCS recommendation the next day.
Dulles, the Secretary of State was visiting India and told Nehru to deliver a message to Zhou Enlai: if peace was not speedily attained, the United States would begin to bomb north of Yalu, and US had recently tested atomic shells.
33 . As a side question, did US threaten China with nukes after the Korean war?
US threatened China with nuclear weapons again in 1959.
From recently declassified documents, President Kennedy considered using nukes to bomb Chinese nuclear facilities in early 1960s , when China was on the verge of exploding its own bomb, but JFK was assassinated and the plan was dropped by President Johnson.
Facing nuclear threat, Chairman Mao said:"we need to have some atomic bombs too". In 1964, China exploded its first A-Bomb, 30 months later, in 1967, it exploded its first H-Bomb, since then, China has developed a variety of strategic and tactical weapons, China also produced missiles of various ranges, initially targeting US bases at Japan and Philippines, and eventually the North America continent. Mao also said:"We must have nuclear submarines even if this would take us ten thousand years". China tested its nuclear subs in early 1970s and tested SLBMs later. The exact size of PLA nuclear stockpile is unknown, but reasonable estimate put it in the range of 2000-4000 warheads.
In March 1996, PLA conducted an exercise in the Taiwan Straits, President Clinton sent two carriers to the straits, PLA responded by dispatching its nuclear attack submarines and the US fleet stayed 300 nautical miles off Taiwan, in the meantime, PLA SAF (Secondary Artillery Force) conducted exercise to retaliate against enemy strategic strikes, PLA Vice Chief of Staff, Gen. Xiong Guangkai reportedly hinted that US cares more about LA than Taiwan.
34 . How many civilians were killed by US forces in Korea?
About 3 million. (To be detailed)
35 . What was the lesson China learned from the Korean war?
Chinese learned that united as a nation, they can defeat any enemy.
Red China explodes atomic bomb
TOKYO, Oct. 16, 1964 (UPI) -- Red China today exploded its first atomic bomb. It then immediately proposed a world conference to ban use of nuclear weapons. The official New China News Agency, in a Peking broadcast monitored here, said the bomb was exploded in "western region of China" at 3 p.m. Peking time.
The agency said that Red China had been forced to build a nuclear bomb because of a "nuclear threat posed by the United States."
It boasted that the explosion was a "major achievement for the Chinese people," that it strengthened Red China's national defense and was a "major contribution to the cause of world peace."
The historic explosion came less that 24 hours after the ouster of Soviet Premier Nikita Khrushchev and 17 days after U.S. Secretary of State Dean Rusk had warned such an explosion was imminent. The blast was detected by U.S. monitoring stations.
In New York City a spokesman for Fordham University said the university seismograph recorded what appeared to be a "strong quake" between Mongolia and the Kurile Islands at 3:13 a.m. today.
Military experts believed that today's blast -- making Red China the world's fifth nuclear power -- occurred in Sinkiang Province bordering on Russia.
They said however, that it would be five to 10 years before Red China could develop today's bomb into a useful military weapon. Diplomats, however, said it would be a powerful propaganda weapon.
Proposing a world conference, Red China said its purpose in developing an atomic bomb was defensive and that it never would be "the first to use nuclear weapons."
"The development of nuclear weapons by China is for defense and for protecting the Chinese people from the danger of the United States launching a nuclear war," it added.
President Truman announces Soviets have exploded a nuclear device
In a surprisingly low-key and carefully worded statement, President Harry S. Truman informs the American people that the Soviets have exploded a nuclear bomb. The Soviet accomplishment, years ahead of what was thought possible by most U.S. officials, caused a panic in the American government.
The United States developed the atomic bomb during the latter stages of World War II and dropped two bombs on Japan in August 1945. By the time of the bombings in Japan, relations between the United States and the Soviet Union were already crumbling. Many U.S. officials, including President Truman, came to see America’s atomic monopoly as a valuable asset in the developing Cold War with Russia. Most American officials, and even the majority of scientists in the United States, believed that it would be many years before the Soviets could develop an atomic bomb of their own, and by that time the United States would have achieved a vast numeric superiority. On September 3, 1949, however, U.S. scientists recorded seismic activity from inside the Soviet Union that was unmistakably the result of an underground nuclear test.
Truman, informed of this development, at first refused to believe it. He ordered his scientific and military advisers to recheck their data. Once they confirmed the results, however, Truman had to face the fact that America’s nuclear monopoly was gone. He also had to face the task of informing the American people, for the news was sure to leak. On September 23, he issued a brief statement to the media. “We have evidence,” the statement read, “within recent weeks an atomic explosion occurred in the USSR.” The president attempted to downplay the seriousness of the event by noting that “The eventual development of this new force by other nations was to be expected. This probability has always been taken into account by us.”
Ballistic Missiles and H-bombs
A Dongfeng-1 short-range ballistic missile
China began work on ballistic missile technology in 1955, when physicist Qian Xuesen (of no relation to Qian Sangiang) returned from the United States. Trained at MIT and Caltech, Qian had been a colonel in the United States Army and was charged with interrogating Nazi rocket scientists after World War II. Upon his return to China, Qian was put in charge of the missile and space program known as the Fifth Academy.
On October 25, 1966, China tested its first nuclear missile. As Marshal Nie Rongzhen recalled, “After the launch, I went to the atom bomb test base to see the results of the explosion at the designated target. The missile was deadly accurate. I was proud of our country, which had long been backward but now had its own sophisticated weapons.”
Beginning in 1960, Chinese scientists also began to develop thermonuclear weapons. Once again, the Chinese nuclear program likely benefited from Klaus Fuchs, who passed his rudimentary knowledge of the hydrogen bomb to Qian Sangiang when they met in 1959. China tested its first H-bomb bomb on June 17, 1967, with a force of 3.3 megatons. China acquired thermonuclear weapons only 32 months after its first atomic bomb test, much faster than the United States (over 7 years after its first test) and the Soviet Union (almost 4 years after its first test) took to build their respective hydrogen bombs.
Meanwhile, work resumed on the previously abandoned Jiuquan plant, which produced its first weapons-grade plutonium in September 1968, giving Beijing multiple paths to build nuclear weapons. Although China never signed the Limited Test Ban Treaty, it nonetheless began to conduct underground nuclear tests in 1969, probably because they were more difficult for neighboring countries to detect. In total, China conducted 45 nuclear tests, all at Lop Nur, with the last one on July 29, 1996.
China horror: Huge fireball explosion above Chinese city sparks 'doomsday panic' - VIDEOLink copied
China: Huge fire breaks out near tower blocks in Shenyang
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Footage of a massive terrifying fireball exploding above a densely-populated Chinese city was caught by multiple witnesses. Videos of the fireball explosion quickly went viral, as witnesses took to social media claiming that the explosion "sounded like a bomb blast". However, a lightning bolt was later found to be behind the massive fireball in Shenyang city in China after it struck high-voltage power lines.
Several videos from different angles showed the sudden explosion erupt near several tower blocks.
The building that the lightning bolt struck had been under construction at the time.
Footage of the explosion shows a sudden fireball burst, before a "rain of sparks" rains down on nearby roads.
The powerful explosion could be seen across the city.
Footage of a terrifying massive fireball exploding above a densely-populated Chinese city (Image: TWITTER)
The fireball stunned witnesses as it exploded during evening rush hour traffic (Image: TWITTER)
Astonishingly, Chinese state media reported that the blaze did not cause any casualties nor damage to the tower blocks.
The explosion did not even interrupt the local electrical services or cause any fires.
State broadcaster CCTV reported that the fireball hit the Tiexi District of Shenyang.
The fireball was seen by hundreds of people after it exploded during evening rush hour traffic.
Footage of the explosion shows a sudden fireball burst, before a "rain of sparks" rains down on nearby roads and parks (Image: TWITTER)
Early thermal weapons, such as Greek fire, have existed since ancient times. At its roots, the history of chemical explosives lies in the history of gunpowder.   During the Tang Dynasty in the 9th century, Taoist Chinese alchemists were eagerly trying to find the elixir of immortality.  In the process, they stumbled upon the explosive invention of black powder made from coal, saltpeter, and sulfur in 1044. Gunpowder was the first form of chemical explosives and by 1161, the Chinese were using explosives for the first time in warfare.    The Chinese would incorporate explosives fired from bamboo or bronze tubes known as bamboo fire crackers. The Chinese also inserted live rats inside the bamboo fire crackers when fired toward the enemy, the flaming rats created great psychological ramifications—scaring enemy soldiers away and causing cavalry units to go wild. 
The first useful explosive stronger than black powder was nitroglycerin, developed in 1847. Since nitroglycerin is a liquid and highly unstable, it was replaced by nitrocellulose, trinitrotoluene (TNT) in 1863, smokeless powder, dynamite in 1867 and gelignite (the latter two being sophisticated stabilized preparations of nitroglycerin rather than chemical alternatives, both invented by Alfred Nobel). World War I saw the adoption of TNT in artillery shells. World War II saw an extensive use of new explosives (see List of explosives used during World War II).
In turn, these have largely been replaced by more powerful explosives such as C-4 and PETN. However, C-4 and PETN react with metal and catch fire easily, yet unlike TNT, C-4 and PETN are waterproof and malleable. 
The largest commercial application of explosives is mining. Whether the mine is on the surface or is buried underground, the detonation or deflagration of either a high or low explosive in a confined space can be used to liberate a fairly specific sub-volume of a brittle material in a much larger volume of the same or similar material. The mining industry tends to use nitrate-based explosives such as emulsions of fuel oil and ammonium nitrate solutions, mixtures of ammonium nitrate prills (fertilizer pellets) and fuel oil (ANFO) and gelatinous suspensions or slurries of ammonium nitrate and combustible fuels.
In Materials Science and Engineering, explosives are used in cladding (explosion welding). A thin plate of some material is placed atop a thick layer of a different material, both layers typically of metal. Atop the thin layer is placed an explosive. At one end of the layer of explosive, the explosion is initiated. The two metallic layers are forced together at high speed and with great force. The explosion spreads from the initiation site throughout the explosive. Ideally, this produces a metallurgical bond between the two layers.
As the length of time the shock wave spends at any point is small, we can see mixing of the two metals and their surface chemistries, through some fraction of the depth, and they tend to be mixed in some way. It is possible that some fraction of the surface material from either layer eventually gets ejected when the end of material is reached. Hence, the mass of the now "welded" bilayer, may be less than the sum of the masses of the two initial layers.
There are applications [ which? ] where a shock wave, and electrostatics, can result in high velocity projectiles. [ citation needed ]
An explosion is a type of spontaneous chemical reaction that, once initiated, is driven by both a large exothermic change (great release of heat) and a large positive entropy change (great quantities of gases are released) in going from reactants to products, thereby constituting a thermodynamically favorable process in addition to one that propagates very rapidly. Thus, explosives are substances that contain a large amount of energy stored in chemical bonds. The energetic stability of the gaseous products and hence their generation comes from the formation of strongly bonded species like carbon monoxide, carbon dioxide, and (di)nitrogen, which contain strong double and triple bonds having bond strengths of nearly 1 MJ/mole. Consequently, most commercial explosives are organic compounds containing -NO2, -ONO2 and -NHNO2 groups that, when detonated, release gases like the aforementioned (e.g., nitroglycerin, TNT, HMX, PETN, nitrocellulose). 
An explosive is classified as a low or high explosive according to its rate of combustion: low explosives burn rapidly (or deflagrate), while high explosives detonate. While these definitions are distinct, the problem of precisely measuring rapid decomposition makes practical classification of explosives difficult.
Traditional explosives mechanics is based on the shock-sensitive rapid oxidation of carbon and hydrogen to carbon dioxide, carbon monoxide and water in the form of steam. Nitrates typically provide the required oxygen to burn the carbon and hydrogen fuel. High explosives tend to have the oxygen, carbon and hydrogen contained in one organic molecule, and less sensitive explosives like ANFO are combinations of fuel (carbon and hydrogen fuel oil) and ammonium nitrate. A sensitizer such as powdered aluminum may be added to an explosive to increase the energy of the detonation. Once detonated, the nitrogen portion of the explosive formulation emerges as nitrogen gas and toxic nitric oxides.
The chemical decomposition of an explosive may take years, days, hours, or a fraction of a second. The slower processes of decomposition take place in storage and are of interest only from a stability standpoint. Of more interest are the other two rapid forms besides decomposition: deflagration and detonation.
In deflagration, decomposition of the explosive material is propagated by a flame front which moves slowly through the explosive material at speeds less than the speed of sound within the substance (usually below 1000 m/s)  in contrast to detonation, which occurs at speeds greater than the speed of sound. Deflagration is a characteristic of low explosive material.
This term is used to describe an explosive phenomenon whereby the decomposition is propagated by an explosive shock wave traversing the explosive material at speeds greater than the speed of sound within the substance.  The shock front is capable of passing through the high explosive material at supersonic speeds, typically thousands of metres per second.
In addition to chemical explosives, there are a number of more exotic explosive materials, and exotic methods of causing explosions. Examples include nuclear explosives, and abruptly heating a substance to a plasma state with a high-intensity laser or electric arc.
Laser- and arc-heating are used in laser detonators, exploding-bridgewire detonators, and exploding foil initiators, where a shock wave and then detonation in conventional chemical explosive material is created by laser- or electric-arc heating. Laser and electric energy are not currently used in practice to generate most of the required energy, but only to initiate reactions.
To determine the suitability of an explosive substance for a particular use, its physical properties must first be known. The usefulness of an explosive can only be appreciated when the properties and the factors affecting them are fully understood. Some of the more important characteristics are listed below:
Sensitivity refers to the ease with which an explosive can be ignited or detonated, i.e., the amount and intensity of shock, friction, or heat that is required. When the term sensitivity is used, care must be taken to clarify what kind of sensitivity is under discussion. The relative sensitivity of a given explosive to impact may vary greatly from its sensitivity to friction or heat. Some of the test methods used to determine sensitivity relate to:
- Impact – Sensitivity is expressed in terms of the distance through which a standard weight must be dropped onto the material to cause it to explode.
- Friction – Sensitivity is expressed in terms of the amount of pressure applied to the material in order to create enough friction to cause a reaction.
- Heat – Sensitivity is expressed in terms of the temperature at which decomposition of the material occurs.
Specific explosives (usually but not always highly sensitive on one or more of the three above axes) may be idiosyncratically sensitive to such factors as pressure drop, acceleration, the presence of sharp edges or rough surfaces, incompatible materials, or even—in rare cases—nuclear or electromagnetic radiation. These factors present special hazards that may rule out any practical utility.
Sensitivity is an important consideration in selecting an explosive for a particular purpose. The explosive in an armor-piercing projectile must be relatively insensitive, or the shock of impact would cause it to detonate before it penetrated to the point desired. The explosive lenses around nuclear charges are also designed to be highly insensitive, to minimize the risk of accidental detonation.
Sensitivity to initiation Edit
The index of the capacity of an explosive to be initiated into detonation in a sustained manner. It is defined by the power of the detonator which is certain to prime the explosive to a sustained and continuous detonation. Reference is made to the Sellier-Bellot scale that consists of a series of 10 detonators, from n. 1 to n. 10, each of which corresponds to an increasing charge weight. In practice, most of the explosives on the market today are sensitive to an n. 8 detonator, where the charge corresponds to 2 grams of mercury fulminate.
Velocity of detonation Edit
The velocity with which the reaction process propagates in the mass of the explosive. Most commercial mining explosives have detonation velocities ranging from 1800 m/s to 8000 m/s. Today, velocity of detonation can be measured with accuracy. Together with density it is an important element influencing the yield of the energy transmitted for both atmospheric over-pressure and ground acceleration. By definition, a "low explosive", such as black powder, or smokeless gunpowder has a burn rate of 171–631 m/s.  In contrast, a "high explosive", whether a primary, such as detonating cord, or a secondary, such as TNT or C-4 has a significantly higher burn rate. 
Stability is the ability of an explosive to be stored without deterioration.
The following factors affect the stability of an explosive:
- Chemical constitution. In the strictest technical sense, the word "stability" is a thermodynamic term referring to the energy of a substance relative to a reference state or to some other substance. However, in the context of explosives, stability commonly refers to ease of detonation, which is concerned with kinetics (i.e., rate of decomposition). It is perhaps best, then, to differentiate between the terms thermodynamically stable and kinetically stable by referring to the former as "inert." Contrarily, a kinetically unstable substance is said to be "labile." It is generally recognized that certain groups like nitro (–NO2), nitrate (–ONO2), and azide (–N3), are intrinsically labile. Kinetically, there exists a low activation barrier to the decomposition reaction. Consequently, these compounds exhibit high sensitivity to flame or mechanical shock. The chemical bonding in these compounds is characterized as predominantly covalent and thus they are not thermodynamically stabilized by a high ionic-lattice energy. Furthermore, they generally have positive enthalpies of formation and there is little mechanistic hindrance to internal molecular rearrangement to yield the more thermodynamically stable (more strongly bonded) decomposition products. For example, in lead azide, Pb(N3)2, the nitrogen atoms are already bonded to one another, so decomposition into Pb and N2  is relatively easy.
- Temperature of storage. The rate of decomposition of explosives increases at higher temperatures. All standard military explosives may be considered to have a high degree of stability at temperatures from –10 to +35 °C, but each has a high temperature at which its rate of decomposition rapidly accelerates and stability is reduced. As a rule of thumb, most explosives become dangerously unstable at temperatures above 70 °C.
- Exposure to sunlight. When exposed to the ultraviolet rays of sunlight, many explosive compounds containing nitrogen groups rapidly decompose, affecting their stability.
- Electrical discharge.Electrostatic or spark sensitivity to initiation is common in a number of explosives. Static or other electrical discharge may be sufficient to cause a reaction, even detonation, under some circumstances. As a result, safe handling of explosives and pyrotechnics usually requires proper electrical grounding of the operator.
Power, performance, and strength Edit
The term power or performance as applied to an explosive refers to its ability to do work. In practice it is defined as the explosive's ability to accomplish what is intended in the way of energy delivery (i.e., fragment projection, air blast, high-velocity jet, underwater shock and bubble energy, etc.). Explosive power or performance is evaluated by a tailored series of tests to assess the material for its intended use. Of the tests listed below, cylinder expansion and air-blast tests are common to most testing programs, and the others support specific applications.
- Cylinder expansion test. A standard amount of explosive is loaded into a long hollow cylinder, usually of copper, and detonated at one end. Data is collected concerning the rate of radial expansion of the cylinder and the maximum cylinder wall velocity. This also establishes the Gurney energy or 2E.
- Cylinder fragmentation. A standard steel cylinder is loaded with explosive and detonated in a sawdust pit. The fragments are collected and the size distribution analyzed.
- Detonation pressure (Chapman–Jouguet condition).Detonation pressure data derived from measurements of shock waves transmitted into water by the detonation of cylindrical explosive charges of a standard size.
- Determination of critical diameter. This test establishes the minimum physical size a charge of a specific explosive must be to sustain its own detonation wave. The procedure involves the detonation of a series of charges of different diameters until difficulty in detonation wave propagation is observed.
- Massive-diameter detonation velocity. Detonation velocity is dependent on loading density (c), charge diameter, and grain size. The hydrodynamic theory of detonation used in predicting explosive phenomena does not include the diameter of the charge, and therefore a detonation velocity, for a massive diameter. This procedure requires the firing of a series of charges of the same density and physical structure, but different diameters, and the extrapolation of the resulting detonation velocities to predict the detonation velocity of a charge of a massive diameter.
- Pressure versus scaled distance. A charge of a specific size is detonated and its pressure effects measured at a standard distance. The values obtained are compared with those for TNT.
- Impulse versus scaled distance. A charge of a specific size is detonated and its impulse (the area under the pressure-time curve) measured as a function of distance. The results are tabulated and expressed as TNT equivalents.
- Relative bubble energy (RBE). A 5 to 50 kg charge is detonated in water and piezoelectric gauges measure peak pressure, time constant, impulse, and energy.
In addition to strength, explosives display a second characteristic, which is their shattering effect or brisance (from the French meaning to "break"), which is distinguished and separate from their total work capacity. This characteristic is of practical importance in determining the effectiveness of an explosion in fragmenting shells, bomb casings, grenades, and the like. The rapidity with which an explosive reaches its peak pressure (power) is a measure of its brisance. Brisance values are primarily employed in France and Russia.
The sand crush test is commonly employed to determine the relative brisance in comparison to TNT. No test is capable of directly comparing the explosive properties of two or more compounds it is important to examine the data from several such tests (sand crush, trauzl, and so forth) in order to gauge relative brisance. True values for comparison require field experiments.
Density of loading refers to the mass of an explosive per unit volume. Several methods of loading are available, including pellet loading, cast loading, and press loading, the choice being determined by the characteristics of the explosive. Dependent upon the method employed, an average density of the loaded charge can be obtained that is within 80–99% of the theoretical maximum density of the explosive. High load density can reduce sensitivity by making the mass more resistant to internal friction. However, if density is increased to the extent that individual crystals are crushed, the explosive may become more sensitive. Increased load density also permits the use of more explosive, thereby increasing the power of the warhead. It is possible to compress an explosive beyond a point of sensitivity, known also as dead-pressing, in which the material is no longer capable of being reliably initiated, if at all.
Volatility is the readiness with which a substance vaporizes. Excessive volatility often results in the development of pressure within rounds of ammunition and separation of mixtures into their constituents. Volatility affects the chemical composition of the explosive such that a marked reduction in stability may occur, which results in an increase in the danger of handling.
Hygroscopicity and water resistance Edit
The introduction of water into an explosive is highly undesirable since it reduces the sensitivity, strength, and velocity of detonation of the explosive. Hygroscopicity is a measure of a material's moisture-absorbing tendencies. Moisture affects explosives adversely by acting as an inert material that absorbs heat when vaporized, and by acting as a solvent medium that can cause undesired chemical reactions. Sensitivity, strength, and velocity of detonation are reduced by inert materials that reduce the continuity of the explosive mass. When the moisture content evaporates during detonation, cooling occurs, which reduces the temperature of reaction. Stability is also affected by the presence of moisture since moisture promotes decomposition of the explosive and, in addition, causes corrosion of the explosive's metal container.
Explosives considerably differ from one another as to their behavior in the presence of water. Gelatin dynamites containing nitroglycerine have a degree of water resistance. Explosives based on ammonium nitrate have little or no water resistance as ammonium nitrate is highly soluble in water and is hygroscopic.
Many explosives are toxic to some extent. Manufacturing inputs can also be organic compounds or hazardous materials that require special handing due to risks (such as carcinogens). The decomposition products, residual solids, or gases of some explosives can be toxic, whereas others are harmless, such as carbon dioxide and water.
Examples of harmful by-products are:
- Heavy metals, such as lead, mercury, and barium from primers (observed in high-volume firing ranges)
- Nitric oxides from TNT
- Perchlorates when used in large quantities
"Green explosives" seek to reduce environment and health impacts. An example of such is the lead-free primary explosive copper(I) 5-nitrotetrazolate, an alternative to lead azide.  One variety of a green explosive is CDP explosives, whose synthesis does not involve any toxic ingredients, consumes carbon dioxide while detonating and does not release any nitric oxides into the atmosphere when used. [ citation needed ]
Explosive train Edit
Explosive material may be incorporated in the explosive train of a device or system. An example is a pyrotechnic lead igniting a booster, which causes the main charge to detonate.
Volume of products of explosion Edit
The most widely used explosives are condensed liquids or solids converted to gaseous products by explosive chemical reactions and the energy released by those reactions. The gaseous products of complete reaction are typically carbon dioxide, steam, and nitrogen.  Gaseous volumes computed by the ideal gas law tend to be too large at high pressures characteristic of explosions.  Ultimate volume expansion may be estimated at three orders of magnitude, or one liter per gram of explosive. Explosives with an oxygen deficit will generate soot or gases like carbon monoxide and hydrogen, which may react with surrounding materials such as atmospheric oxygen.  Attempts to obtain more precise volume estimates must consider the possibility of such side reactions, condensation of steam, and aqueous solubility of gases like carbon dioxide. 
By comparison, CDP detonation is based on the rapid reduction of carbon dioxide to carbon with the abundant release of energy. Rather than produce typical waste gases like carbon dioxide, carbon monoxide, nitrogen and nitric oxides, CDP is different. Instead, the highly energetic reduction of carbon dioxide to carbon vaporizes and pressurizes excess dry ice at the wave front, which is the only gas released from the detonation. The velocity of detonation for CDP formulations can therefore be customized by adjusting the weight percentage of reducing agent and dry ice. CDP detonations produce a large amount of solid materials that can have great commercial value as an abrasive:
Example – CDP Detonation Reaction with Magnesium: XCO2 + 2Mg → 2MgO + C + (X-1)CO2
The products of detonation in this example are magnesium oxide, carbon in various phases including diamond, and vaporized excess carbon dioxide that was not consumed by the amount of magnesium in the explosive formulation. 
Oxygen balance (OB% or Ω) Edit
Oxygen balance is an expression that is used to indicate the degree to which an explosive can be oxidized. If an explosive molecule contains just enough oxygen to convert all of its carbon to carbon dioxide, all of its hydrogen to water, and all of its metal to metal oxide with no excess, the molecule is said to have a zero oxygen balance. The molecule is said to have a positive oxygen balance if it contains more oxygen than is needed and a negative oxygen balance if it contains less oxygen than is needed.  The sensitivity, strength, and brisance of an explosive are all somewhat dependent upon oxygen balance and tend to approach their maxima as oxygen balance approaches zero.
Oxygen balance applies to traditional explosives mechanics with the assumption that carbon is oxidized to carbon monoxide and carbon dioxide during detonation. In what seems like a paradox to an explosives expert, Cold Detonation Physics uses carbon in its most highly oxidized state as the source of oxygen in the form of carbon dioxide. Oxygen balance, therefore, either does not apply to a CDP formulation or must be calculated without including the carbon in the carbon dioxide. 
Chemical composition Edit
A chemical explosive may consist of either a chemically pure compound, such as nitroglycerin, or a mixture of a fuel and an oxidizer, such as black powder or grain dust and air.
Pure compounds Edit
Some chemical compounds are unstable in that, when shocked, they react, possibly to the point of detonation. Each molecule of the compound dissociates into two or more new molecules (generally gases) with the release of energy.
- Nitroglycerin: A highly unstable and sensitive liquid
- Acetone peroxide: A very unstable white organic peroxide
- TNT: Yellow insensitive crystals that can be melted and cast without detonation
- Cellulose nitrate: A nitrated polymer which can be a high or low explosive depending on nitration level and conditions
- RDX, PETN, HMX: Very powerful explosives which can be used pure or in plastic explosives
- C-4 (or Composition C-4): An RDXplastic explosive plasticized to be adhesive and malleable
The above compositions may describe most of the explosive material, but a practical explosive will often include small percentages of other substances. For example, dynamite is a mixture of highly sensitive nitroglycerin with sawdust, powdered silica, or most commonly diatomaceous earth, which act as stabilizers. Plastics and polymers may be added to bind powders of explosive compounds waxes may be incorporated to make them safer to handle aluminium powder may be introduced to increase total energy and blast effects. Explosive compounds are also often "alloyed": HMX or RDX powders may be mixed (typically by melt-casting) with TNT to form Octol or Cyclotol.
Oxidized fuel Edit
An oxidizer is a pure substance (molecule) that in a chemical reaction can contribute some atoms of one or more oxidizing elements, in which the fuel component of the explosive burns. On the simplest level, the oxidizer may itself be an oxidizing element, such as gaseous or liquid oxygen.
- Black powder: Potassium nitrate, charcoal and sulfur
- Flash powder: Fine metal powder (usually aluminium or magnesium) and a strong oxidizer (e.g. potassium chlorate or perchlorate)
- Ammonal: Ammonium nitrate and aluminium powder
- Armstrong's mixture: Potassium chlorate and red phosphorus. This is a very sensitive mixture. It is a primary high explosive in which sulfur is substituted for some or all of the phosphorus to slightly decrease sensitivity.
- Cold Detonation Physics: Combinations of carbon dioxide in the form of dry ice (an untraditional oxygen source), and powdered reducing agents (fuel) like magnesium and aluminum. 
- Sprengel explosives: A very general class incorporating any strong oxidizer and highly reactive fuel, although in practice the name was most commonly applied to mixtures of chlorates and nitroaromatics.
- ANFO: Ammonium nitrate and fuel oil
- Cheddites: Chlorates or perchlorates and oil
- Oxyliquits: Mixtures of organic materials and liquid oxygen
- Panclastites: Mixtures of organic materials and dinitrogen tetroxide
Availability and cost Edit
The availability and cost of explosives are determined by the availability of the raw materials and the cost, complexity, and safety of the manufacturing operations.
By sensitivity Edit
A primary explosive is an explosive that is extremely sensitive to stimuli such as impact, friction, heat, static electricity, or electromagnetic radiation. Some primary explosives are also known as contact explosives. A relatively small amount of energy is required for initiation. As a very general rule, primary explosives are considered to be those compounds that are more sensitive than PETN. As a practical measure, primary explosives are sufficiently sensitive that they can be reliably initiated with a blow from a hammer however, PETN can also usually be initiated in this manner, so this is only a very broad guideline. Additionally, several compounds, such as nitrogen triiodide, are so sensitive that they cannot even be handled without detonating. Nitrogen triiodide is so sensitive that it can be reliably detonated by exposure to alpha radiation it is the only explosive for which this is true. [ citation needed ]
Primary explosives are often used in detonators or to trigger larger charges of less sensitive secondary explosives. Primary explosives are commonly used in blasting caps and percussion caps to translate a physical shock signal. In other situations, different signals such as electrical or physical shock, or, in the case of laser detonation systems, light, are used to initiate an action, i.e., an explosion. A small quantity, usually milligrams, is sufficient to initiate a larger charge of explosive that is usually safer to handle.
Examples of primary high explosives are:
A secondary explosive is less sensitive than a primary explosive and requires substantially more energy to be initiated. Because they are less sensitive, they are usable in a wider variety of applications and are safer to handle and store. Secondary explosives are used in larger quantities in an explosive train and are usually initiated by a smaller quantity of a primary explosive.
Examples of secondary explosives include TNT and RDX.
Tertiary explosives, also called blasting agents, are so insensitive to shock that they cannot be reliably detonated by practical quantities of primary explosive, and instead require an intermediate explosive booster of secondary explosive. These are often used for safety and the typically lower costs of material and handling. The largest consumers are large-scale mining and construction operations.
Most tertiaries include a fuel and an oxidizer. ANFO can be a tertiary explosive if its reaction rate is slow.
By velocity Edit
Low explosives are compounds where the rate of decomposition proceeds through the material at less than the speed of sound. The decomposition is propagated by a flame front (deflagration) which travels much more slowly through the explosive material than a shock wave of a high explosive. Under normal conditions, low explosives undergo deflagration at rates that vary from a few centimetres per second to approximately 0.4 kilometres per second (1,300 ft/s). It is possible for them to deflagrate very quickly, producing an effect similar to a detonation. This can happen under higher pressure (such as when gunpowder deflagrates inside the confined space of a bullet casing, accelerating the bullet to well beyond the speed of sound) or temperature.
A low explosive is usually a mixture of a combustible substance and an oxidant that decomposes rapidly (deflagration) however, they burn more slowly than a high explosive, which has an extremely fast burn rate. [ citation needed ]
Low explosives are normally employed as propellants. Included in this group are petroleum products such as propane and gasoline, gunpowder (including smokeless powder), and light pyrotechnics, such as flares and fireworks, but can replace high explosives in certain applications, see gas pressure blasting. [ citation needed ]
High explosives (HE) are explosive materials that detonate, meaning that the explosive shock front passes through the material at a supersonic speed. High explosives detonate with explosive velocity of about 3–9 kilometres per second (9,800–29,500 ft/s). For instance, TNT has a detonation (burn) rate of approximately 5.8 km/s (19,000 feet per second), detonating cord of 6.7 km/s (22,000 feet per second), and C-4 about 8.5 km/s (29,000 feet per second). They are normally employed in mining, demolition, and military applications. They can be divided into two explosives classes differentiated by sensitivity: primary explosive and secondary explosive. The term high explosive is in contrast with the term low explosive, which explodes (deflagrates) at a lower rate.
Countless high-explosive compounds are chemically possible, but commercially and militarily important ones have included NG, TNT, TNX, RDX, HMX, PETN, TATB, and HNS.
By physical form Edit
Explosives are often characterized by the physical form that the explosives are produced or used in. These use forms are commonly categorized as: 
- Castings , a.k.a. putties
- Blasting agents
- Slurries and gels
Shipping label classifications Edit
Shipping labels and tags may include both United Nations and national markings.
United Nations markings include numbered Hazard Class and Division (HC/D) codes and alphabetic Compatibility Group codes. Though the two are related, they are separate and distinct. Any Compatibility Group designator can be assigned to any Hazard Class and Division. An example of this hybrid marking would be a consumer firework, which is labeled as 1.4G or 1.4S.
Examples of national markings would include United States Department of Transportation (U.S. DOT) codes.
United Nations Organization (UNO) Hazard Class and Division (HC/D) Edit
The Hazard Class and Division (HC/D) is a numeric designator within a hazard class indicating the character, predominance of associated hazards, and potential for causing personnel casualties and property damage. It is an internationally accepted system that communicates using the minimum amount of markings the primary hazard associated with a substance. 
Listed below are the Divisions for Class 1 (Explosives):
- 1.1 Mass Detonation Hazard. With HC/D 1.1, it is expected that if one item in a container or pallet inadvertently detonates, the explosion will sympathetically detonate the surrounding items. The explosion could propagate to all or the majority of the items stored together, causing a mass detonation. There will also be fragments from the item's casing and/or structures in the blast area.
- 1.2 Non-mass explosion, fragment-producing. HC/D 1.2 is further divided into three subdivisions, HC/D 1.2.1, 1.2.2 and 1.2.3, to account for the magnitude of the effects of an explosion.
- 1.3 Mass fire, minor blast or fragment hazard. Propellants and many pyrotechnic items fall into this category. If one item in a package or stack initiates, it will usually propagate to the other items, creating a mass fire.
- 1.4 Moderate fire, no blast or fragment. HC/D 1.4 items are listed in the table as explosives with no significant hazard. Most small arms ammunition (including loaded weapons) and some pyrotechnic items fall into this category. If the energetic material in these items inadvertently initiates, most of the energy and fragments will be contained within the storage structure or the item containers themselves.
- 1.5 mass detonation hazard, very insensitive.
- 1.6detonation hazard without mass detonation hazard, extremely insensitive.
To see an entire UNO Table, browse Paragraphs 3-8 and 3-9 of NAVSEA OP 5, Vol. 1, Chapter 3.
Class 1 Compatibility Group Edit
Compatibility Group codes are used to indicate storage compatibility for HC/D Class 1 (explosive) materials. Letters are used to designate 13 compatibility groups as follows.
- A: Primary explosive substance (1.1A).
- B: An article containing a primary explosive substance and not containing two or more effective protective features. Some articles, such as detonator assemblies for blasting and primers, cap-type, are included. (1.1B, 1.2B, 1.4B).
- C: Propellant explosive substance or other deflagrating explosive substance or article containing such explosive substance (1.1C, 1.2C, 1.3C, 1.4C). These are bulk propellants, propelling charges, and devices containing propellants with or without means of ignition. Examples include single-based propellant, double-based propellant, triple-based propellant, and composite propellants, solid propellantrocket motors and ammunition with inert projectiles.
- D: Secondary detonating explosive substance or black powder or article containing a secondary detonating explosive substance, in each case without means of initiation and without a propelling charge, or article containing a primary explosive substance and containing two or more effective protective features. (1.1D, 1.2D, 1.4D, 1.5D).
- E: Article containing a secondary detonating explosive substance without means of initiation, with a propelling charge (other than one containing flammable liquid, gel or hypergolic liquid) (1.1E, 1.2E, 1.4E).
- F containing a secondarydetonating explosive substance with its means of initiation, with a propelling charge (other than one containing flammable liquid, gel or hypergolic liquid) or without a propelling charge (1.1F, 1.2F, 1.3F, 1.4F).
- G: Pyrotechnic substance or article containing a pyrotechnic substance, or article containing both an explosive substance and an illuminating, incendiary, tear-producing or smoke-producing substance (other than a water-activated article or one containing white phosphorus, phosphide or flammable liquid or gel or hypergolic liquid) (1.1G, 1.2G, 1.3G, 1.4G). Examples include Flares, signals, incendiary or illuminating ammunition and other smoke and tear producing devices.
- H: Article containing both an explosive substance and white phosphorus (1.2H, 1.3H). These articles will spontaneously combust when exposed to the atmosphere.
- J: Article containing both an explosive substance and flammable liquid or gel (1.1J, 1.2J, 1.3J). This excludes liquids or gels which are spontaneously flammable when exposed to water or the atmosphere, which belong in group H. Examples include liquid or gel filled incendiary ammunition, fuel-air explosive (FAE) devices, and flammable liquid fueled missiles.
- K: Article containing both an explosive substance and a toxic chemical agent (1.2K, 1.3K)
- L Explosive substance or article containing an explosive substance and presenting a special risk (e.g., due to water-activation or presence of hypergolic liquids, phosphides, or pyrophoric substances) needing isolation of each type (1.1L, 1.2L, 1.3L). Damaged or suspect ammunition of any group belongs in this group.
- N: Articles containing only extremely insensitive detonating substances (1.6N).
- S: Substance or article so packed or designed that any hazardous effects arising from accidental functioning are limited to the extent that they do not significantly hinder or prohibit fire fighting or other emergency response efforts in the immediate vicinity of the package (1.4S).
The legality of possessing or using explosives varies by jurisdiction. Various countries around the world have enacted explosives law and require licenses to manufacture, distribute, store, use, possess explosives or ingredients.
In the Netherlands, the civil and commercial use of explosives is covered under the Wet explosieven voor civiel gebruik (explosives for civil use Act), in accordance with EU directive nr. 93/15/EEG  (Dutch). The illegal use of explosives is covered under the Wet Wapens en Munitie (Weapons and Munition Act)  (Dutch).
The new Explosives Regulations 2014 (ER 2014)  came into force on 1 October 2014 and defines "explosive" as:
"a) any explosive article or explosive substance which would —
(i) if packaged for transport, be classified in accordance with the United Nations Recommendations as falling within Class 1 or
(ii) be classified in accordance with the United Nations Recommendations as —
(aa) being unduly sensitive or so reactive as to be subject to spontaneous reaction and accordingly too dangerous to transport, and
(bb) falling within Class 1 or
(b) a desensitised explosive,
but it does not include an explosive substance produced as part of a manufacturing process which thereafter reprocesses it in order to produce a substance or preparation which is not an explosive substance" 
"Anyone who wishes to acquire and or keep relevant explosives needs to contact their local police explosives liaison officer. All explosives are relevant explosives apart from those listed under Schedule 2 of Explosives Regulations 2014." 
United States Edit
During World War I, numerous laws were created to regulate war related industries and increase security within the United States. In 1917, the 65th United States Congress created many laws, including the Espionage Act of 1917 and Explosives Act of 1917.
The Explosives Act of 1917 (session 1, chapter 83, 40 Stat. 385) was signed on 6 October 1917 and went into effect on 16 November 1917. The legal summary is "An Act to prohibit the manufacture, distribution, storage, use, and possession in time of war of explosives, providing regulations for the safe manufacture, distribution, storage, use, and possession of the same, and for other purposes". This was the first federal regulation of licensing explosives purchases. The act was deactivated after World War I ended. 
After the United States entered World War II, the Explosives Act of 1917 was reactivated. In 1947, the act was deactivated by President Truman. 
Nuclear weapons have been used twice in war, both times by the United States against Japan near the end of World War II. On August 6, 1945, the U.S. Army Air Forces detonated a uranium gun-type fission bomb nicknamed "Little Boy" over the Japanese city of Hiroshima three days later, on August 9, the U.S. Army Air Forces detonated a plutonium implosion-type fission bomb nicknamed "Fat Man" over the Japanese city of Nagasaki. These bombings caused injuries that resulted in the deaths of approximately 200,000 civilians and military personnel.  The ethics of these bombings and their role in Japan's surrender are subjects of debate.
Since the atomic bombings of Hiroshima and Nagasaki, nuclear weapons have been detonated over 2,000 times for testing and demonstration. Only a few nations possess such weapons or are suspected of seeking them. The only countries known to have detonated nuclear weapons—and acknowledge possessing them—are (chronologically by date of first test) the United States, the Soviet Union (succeeded as a nuclear power by Russia), the United Kingdom, France, China, India, Pakistan, and North Korea. Israel is believed to possess nuclear weapons, though, in a policy of deliberate ambiguity, it does not acknowledge having them. Germany, Italy, Turkey, Belgium and the Netherlands are nuclear weapons sharing states.    South Africa is the only country to have independently developed and then renounced and dismantled its nuclear weapons. 
The Treaty on the Non-Proliferation of Nuclear Weapons aims to reduce the spread of nuclear weapons, but its effectiveness has been questioned. Modernisation of weapons continues to this day. 
There are two basic types of nuclear weapons: those that derive the majority of their energy from nuclear fission reactions alone, and those that use fission reactions to begin nuclear fusion reactions that produce a large amount of the total energy output. 
All existing nuclear weapons derive some of their explosive energy from nuclear fission reactions. Weapons whose explosive output is exclusively from fission reactions are commonly referred to as atomic bombs or atom bombs (abbreviated as A-bombs). This has long been noted as something of a misnomer, as their energy comes from the nucleus of the atom, just as it does with fusion weapons.
In fission weapons, a mass of fissile material (enriched uranium or plutonium) is forced into supercriticality—allowing an exponential growth of nuclear chain reactions—either by shooting one piece of sub-critical material into another (the "gun" method) or by compression of a sub-critical sphere or cylinder of fissile material using chemically-fueled explosive lenses. The latter approach, the "implosion" method, is more sophisticated than the former.
A major challenge in all nuclear weapon designs is to ensure that a significant fraction of the fuel is consumed before the weapon destroys itself. The amount of energy released by fission bombs can range from the equivalent of just under a ton to upwards of 500,000 tons (500 kilotons) of TNT (4.2 to 2.1 × 10 6 GJ). 
All fission reactions generate fission products, the remains of the split atomic nuclei. Many fission products are either highly radioactive (but short-lived) or moderately radioactive (but long-lived), and as such, they are a serious form of radioactive contamination. Fission products are the principal radioactive component of nuclear fallout. Another source of radioactivity is the burst of free neutrons produced by the weapon. When they collide with other nuclei in the surrounding material, the neutrons transmute those nuclei into other isotopes, altering their stability and making them radioactive.
The most commonly used fissile materials for nuclear weapons applications have been uranium-235 and plutonium-239. Less commonly used has been uranium-233. Neptunium-237 and some isotopes of americium may be usable for nuclear explosives as well, but it is not clear that this has ever been implemented, and their plausible use in nuclear weapons is a matter of dispute. 
The other basic type of nuclear weapon produces a large proportion of its energy in nuclear fusion reactions. Such fusion weapons are generally referred to as thermonuclear weapons or more colloquially as hydrogen bombs (abbreviated as H-bombs), as they rely on fusion reactions between isotopes of hydrogen (deuterium and tritium). All such weapons derive a significant portion of their energy from fission reactions used to "trigger" fusion reactions, and fusion reactions can themselves trigger additional fission reactions. 
Only six countries—United States, Russia, United Kingdom, China, France, and India—have conducted thermonuclear weapon tests. Whether India has detonated a "true" multi-staged thermonuclear weapon is controversial.  North Korea claims to have tested a fusion weapon as of January 2016 [update] , though this claim is disputed.  Thermonuclear weapons are considered much more difficult to successfully design and execute than primitive fission weapons. Almost all of the nuclear weapons deployed today use the thermonuclear design because it is more efficient. 
Thermonuclear bombs work by using the energy of a fission bomb to compress and heat fusion fuel. In the Teller-Ulam design, which accounts for all multi-megaton yield hydrogen bombs, this is accomplished by placing a fission bomb and fusion fuel (tritium, deuterium, or lithium deuteride) in proximity within a special, radiation-reflecting container. When the fission bomb is detonated, gamma rays and X-rays emitted first compress the fusion fuel, then heat it to thermonuclear temperatures. The ensuing fusion reaction creates enormous numbers of high-speed neutrons, which can then induce fission in materials not normally prone to it, such as depleted uranium. Each of these components is known as a "stage", with the fission bomb as the "primary" and the fusion capsule as the "secondary". In large, megaton-range hydrogen bombs, about half of the yield comes from the final fissioning of depleted uranium. 
Virtually all thermonuclear weapons deployed today use the "two-stage" design described above, but it is possible to add additional fusion stages—each stage igniting a larger amount of fusion fuel in the next stage. This technique can be used to construct thermonuclear weapons of arbitrarily large yield, in contrast to fission bombs, which are limited in their explosive force. The largest nuclear weapon ever detonated, the Tsar Bomba of the USSR, which released an energy equivalent of over 50 megatons of TNT (210 PJ), was a three-stage weapon. Most thermonuclear weapons are considerably smaller than this, due to practical constraints from missile warhead space and weight requirements. 
Fusion reactions do not create fission products, and thus contribute far less to the creation of nuclear fallout than fission reactions, but because all thermonuclear weapons contain at least one fission stage, and many high-yield thermonuclear devices have a final fission stage, thermonuclear weapons can generate at least as much nuclear fallout as fission-only weapons.
There are other types of nuclear weapons as well. For example, a boosted fission weapon is a fission bomb that increases its explosive yield through a small number of fusion reactions, but it is not a fusion bomb. In the boosted bomb, the neutrons produced by the fusion reactions serve primarily to increase the efficiency of the fission bomb. There are two types of boosted fission bomb: internally boosted, in which a deuterium-tritium mixture is injected into the bomb core, and externally boosted, in which concentric shells of lithium-deuteride and depleted uranium are layered on the outside of the fission bomb core.
Some nuclear weapons are designed for special purposes a neutron bomb is a thermonuclear weapon that yields a relatively small explosion but a relatively large amount of neutron radiation such a device could theoretically be used to cause massive casualties while leaving infrastructure mostly intact and creating a minimal amount of fallout. The detonation of any nuclear weapon is accompanied by a blast of neutron radiation. Surrounding a nuclear weapon with suitable materials (such as cobalt or gold) creates a weapon known as a salted bomb. This device can produce exceptionally large quantities of long-lived radioactive contamination. It has been conjectured that such a device could serve as a "doomsday weapon" because such a large quantity of radioactivities with half-lives of decades, lifted into the stratosphere where winds would distribute it around the globe, would make all life on the planet extinct.
In connection with the Strategic Defense Initiative, research into the nuclear pumped laser was conducted under the DOD program Project Excalibur but this did not result in a working weapon. The concept involves the tapping of the energy of an exploding nuclear bomb to power a single-shot laser that is directed at a distant target.
During the Starfish Prime high-altitude nuclear test in 1962, an unexpected effect was produced which is called a nuclear electromagnetic pulse. This is an intense flash of electromagnetic energy produced by a rain of high-energy electrons which in turn are produced by a nuclear bomb's gamma rays. This flash of energy can permanently destroy or disrupt electronic equipment if insufficiently shielded. It has been proposed to use this effect to disable an enemy's military and civilian infrastructure as an adjunct to other nuclear or conventional military operations against that enemy. Because the effect is produced by high altitude nuclear detonations, it can produce damage to electronics over a wide, even continental, geographical area.
Research has been done into the possibility of pure fusion bombs: nuclear weapons that consist of fusion reactions without requiring a fission bomb to initiate them. Such a device might provide a simpler path to thermonuclear weapons than one that required the development of fission weapons first, and pure fusion weapons would create significantly less nuclear fallout than other thermonuclear weapons because they would not disperse fission products. In 1998, the United States Department of Energy divulged that the United States had, ". made a substantial investment" in the past to develop pure fusion weapons, but that, "The U.S. does not have and is not developing a pure fusion weapon", and that, "No credible design for a pure fusion weapon resulted from the DOE investment". 
Antimatter, which consists of particles resembling ordinary matter particles in most of their properties but having opposite electric charge, has been considered as a trigger mechanism for nuclear weapons.    A major obstacle is the difficulty of producing antimatter in large enough quantities, and there is no evidence that it is feasible beyond the military domain.  However, the U.S. Air Force funded studies of the physics of antimatter in the Cold War, and began considering its possible use in weapons, not just as a trigger, but as the explosive itself.  A fourth generation nuclear weapon design  is related to, and relies upon, the same principle as antimatter-catalyzed nuclear pulse propulsion. 
Most variation in nuclear weapon design is for the purpose of achieving different yields for different situations, and in manipulating design elements to attempt to minimize weapon size. 
The system used to deliver a nuclear weapon to its target is an important factor affecting both nuclear weapon design and nuclear strategy. The design, development, and maintenance of delivery systems are among the most expensive parts of a nuclear weapons program they account, for example, for 57% of the financial resources spent by the United States on nuclear weapons projects since 1940. 
The simplest method for delivering a nuclear weapon is a gravity bomb dropped from aircraft this was the method used by the United States against Japan. This method places few restrictions on the size of the weapon. It does, however, limit attack range, response time to an impending attack, and the number of weapons that a country can field at the same time. With miniaturization, nuclear bombs can be delivered by both strategic bombers and tactical fighter-bombers. This method is the primary means of nuclear weapons delivery the majority of U.S. nuclear warheads, for example, are free-fall gravity bombs, namely the B61.  [ needs update ]
Preferable from a strategic point of view is a nuclear weapon mounted on a missile, which can use a ballistic trajectory to deliver the warhead over the horizon. Although even short-range missiles allow for a faster and less vulnerable attack, the development of long-range intercontinental ballistic missiles (ICBMs) and submarine-launched ballistic missiles (SLBMs) has given some nations the ability to plausibly deliver missiles anywhere on the globe with a high likelihood of success.
More advanced systems, such as multiple independently targetable reentry vehicles (MIRVs), can launch multiple warheads at different targets from one missile, reducing the chance of a successful missile defense. Today, missiles are most common among systems designed for delivery of nuclear weapons. Making a warhead small enough to fit onto a missile, though, can be difficult. 
Tactical weapons have involved the most variety of delivery types, including not only gravity bombs and missiles but also artillery shells, land mines, and nuclear depth charges and torpedoes for anti-submarine warfare. An atomic mortar has been tested by the United States. Small, two-man portable tactical weapons (somewhat misleadingly referred to as suitcase bombs), such as the Special Atomic Demolition Munition, have been developed, although the difficulty of combining sufficient yield with portability limits their military utility. 
Nuclear warfare strategy is a set of policies that deal with preventing or fighting a nuclear war. The policy of trying to prevent an attack by a nuclear weapon from another country by threatening nuclear retaliation is known as the strategy of nuclear deterrence. The goal in deterrence is to always maintain a second strike capability (the ability of a country to respond to a nuclear attack with one of its own) and potentially to strive for first strike status (the ability to destroy an enemy's nuclear forces before they could retaliate). During the Cold War, policy and military theorists considered the sorts of policies that might prevent a nuclear attack, and they developed game theory models that could lead to stable deterrence conditions. 
Different forms of nuclear weapons delivery (see above) allow for different types of nuclear strategies. The goals of any strategy are generally to make it difficult for an enemy to launch a pre-emptive strike against the weapon system and difficult to defend against the delivery of the weapon during a potential conflict. This can mean keeping weapon locations hidden, such as deploying them on submarines or land mobile transporter erector launchers whose locations are difficult to track, or it can mean protecting weapons by burying them in hardened missile silo bunkers. Other components of nuclear strategies included using missile defenses to destroy the missiles before they land, or implementing civil defense measures using early-warning systems to evacuate citizens to safe areas before an attack.
Weapons designed to threaten large populations or to deter attacks are known as strategic weapons. Nuclear weapons for use on a battlefield in military situations are called tactical weapons.
Critics of nuclear war strategy often suggest that a nuclear war between two nations would result in mutual annihilation. From this point of view, the significance of nuclear weapons is to deter war because any nuclear war would escalate out of mutual distrust and fear, resulting in mutually assured destruction. This threat of national, if not global, destruction has been a strong motivation for anti-nuclear weapons activism.
Critics from the peace movement and within the military establishment [ citation needed ] have questioned the usefulness of such weapons in the current military climate. According to an advisory opinion issued by the International Court of Justice in 1996, the use of (or threat of use of) such weapons would generally be contrary to the rules of international law applicable in armed conflict, but the court did not reach an opinion as to whether or not the threat or use would be lawful in specific extreme circumstances such as if the survival of the state were at stake.
Another deterrence position is that nuclear proliferation can be desirable. In this case, it is argued that, unlike conventional weapons, nuclear weapons deter all-out war between states, and they succeeded in doing this during the Cold War between the U.S. and the Soviet Union.  In the late 1950s and early 1960s, Gen. Pierre Marie Gallois of France, an adviser to Charles de Gaulle, argued in books like The Balance of Terror: Strategy for the Nuclear Age (1961) that mere possession of a nuclear arsenal was enough to ensure deterrence, and thus concluded that the spread of nuclear weapons could increase international stability. Some prominent neo-realist scholars, such as Kenneth Waltz and John Mearsheimer, have argued, along the lines of Gallois, that some forms of nuclear proliferation would decrease the likelihood of total war, especially in troubled regions of the world where there exists a single nuclear-weapon state. Aside from the public opinion that opposes proliferation in any form, there are two schools of thought on the matter: those, like Mearsheimer, who favored selective proliferation,  and Waltz, who was somewhat more non-interventionist.   Interest in proliferation and the stability-instability paradox that it generates continues to this day, with ongoing debate about indigenous Japanese and South Korean nuclear deterrent against North Korea. 
The threat of potentially suicidal terrorists possessing nuclear weapons (a form of nuclear terrorism) complicates the decision process. The prospect of mutually assured destruction might not deter an enemy who expects to die in the confrontation. Further, if the initial act is from a stateless terrorist instead of a sovereign nation, there might not be a nation or specific target to retaliate against. It has been argued, especially after the September 11, 2001, attacks, that this complication calls for a new nuclear strategy, one that is distinct from that which gave relative stability during the Cold War.  Since 1996, the United States has had a policy of allowing the targeting of its nuclear weapons at terrorists armed with weapons of mass destruction. 
Robert Gallucci argues that although traditional deterrence is not an effective approach toward terrorist groups bent on causing a nuclear catastrophe, Gallucci believes that "the United States should instead consider a policy of expanded deterrence, which focuses not solely on the would-be nuclear terrorists but on those states that may deliberately transfer or inadvertently leak nuclear weapons and materials to them. By threatening retaliation against those states, the United States may be able to deter that which it cannot physically prevent.". 
Graham Allison makes a similar case, arguing that the key to expanded deterrence is coming up with ways of tracing nuclear material to the country that forged the fissile material. "After a nuclear bomb detonates, nuclear forensics cops would collect debris samples and send them to a laboratory for radiological analysis. By identifying unique attributes of the fissile material, including its impurities and contaminants, one could trace the path back to its origin."  The process is analogous to identifying a criminal by fingerprints. "The goal would be twofold: first, to deter leaders of nuclear states from selling weapons to terrorists by holding them accountable for any use of their weapons second, to give leaders every incentive to tightly secure their nuclear weapons and materials." 
According to the Pentagon's June 2019 "Doctrine for Joint Nuclear Operations" of the Joint Chiefs of Staffs website Publication, "Integration of nuclear weapons employment with conventional and special operations forces is essential to the success of any mission or operation."  
Today in History: Born on October 10
Henry Cavendish, English physicist who measured the density and mass of the Earth.
Giuseppe Verdi, composer (Rigoletto, Aida).
Helen Hayes, American actress.
Alberto Giacometti, sculptor and painter.
Thelonius Monk, jazz pianist and composer.
James Clavell, novelist (Shogun, Noble House).
Harold Pinter, British playwright (The Homecoming, Betrayal).
Winston Spencer-Churchill, British politician grandson of famed Prime Minister Sir Winston Churchill.
John Prine, singer, songwriter influential for his poem-like lyrics ("The Great Compromise," "Blue Umbrella").
Ben Vereen, actor (Roots miniseries).
Wang Wanxing, Chinese rights advocate prisoner for 13 years in detention centers and psychiatric institutions (Ankang), he is the only person thus far to be released from these institutions and allowed to live in a Western country.
David Lee Roth, singer, songwriter, actor, author lead vocalist for hard rock band Van Halen member of Rock 'n' Roll Hall of Fame (2007).
Tanya Tucker, singer whose first hit, "Delta Dawn," came when she was just 13.
Daniel Pearl, journalist captured and beheaded by Al Queda in Pakistan Daniel Pearl Foundation to promote tolerance and understanding internationally founded in his memory.
Brett Favre, pro football player only pro quarterback to throw for over 70,000 yards, completing 6,000 passes, including over 500 for touchdowns.
Dale Earnhardt Jr., stock car racing driver and team owner won Most Popular Driver Award in NASCAR Sprint Cup Series 10 times (2003–2012).