Nuclear power
Nuclear weapons have enormous power. During fission of uranium
a mass of about a kilogram releases the same amount of energy as
in an explosion of TNT weighing about 20 thousand tons. Fusion reactions are even more energy intensive.
Nuclear munitions are munitions containing a nuclear charge.
Nuclear weapons are:
nuclear warheads of ballistic, anti-aircraft, cruise missiles and torpedoes;
nuclear bombs;
artillery shells, mines and landmines.
The explosion power of nuclear weapons is usually measured in units of TNT equivalent. TNT equivalent is the mass of trinitrotoluene that would provide an explosion equivalent in power to the explosion of a given nuclear weapon. It is usually measured in kilotons (kT) or megatons (MgT). The TNT equivalent is conditional, since the distribution of the energy of a nuclear explosion among various damaging factors depends significantly on the type of ammunition and, in any case, is very different from a chemical explosion. Modern nuclear weapons have a TNT equivalent of several tens of tons to several tens of millions of tons of TNT.
Depending on the power, nuclear weapons are usually divided into 5 calibers: ultra-small (less than 1 kT), small (from 1 to 10 kT), medium (from 10 to 100 kT), large (from 100 kT to 1 MgT), extra-large (over 1 MgT)
Thermonuclear charges are used for super-large, large and medium caliber ammunition; nuclear charges - ultra-small, small and medium calibers, neutron charges are equipped with ammunition - ultra-small and small calibers.
Damaging factors of a nuclear explosion
A nuclear explosion can instantly destroy or disable unprotected people, openly standing equipment, structures and various material assets. The main damaging factors of a nuclear explosion (NFE) are:
shock wave;
light radiation;
penetrating radiation;
radioactive contamination of the area;
electromagnetic pulse (EMP).
During a nuclear explosion in the atmosphere, the distribution of released energy between PFYVs is approximately the following: about 50% for the shock wave, 35% for light radiation, 10% for radioactive contamination and 5% for penetrating radiation and EMR.
Shock wave
The shock wave in most cases is the main damaging factor of a nuclear explosion. By its nature, it is similar to the shock wave of a completely ordinary explosion, but it lasts longer and has much greater destructive power. The shock wave of a nuclear explosion can injure people, destroy structures and damage military equipment at a considerable distance from the center of the explosion.
A shock wave is an area of strong air compression that propagates at high speed in all directions from the center of the explosion. Its propagation speed depends on the air pressure at the front of the shock wave; near the center of the explosion it is several times higher than the speed of sound, but with increasing distance from the explosion site it drops sharply. In the first 2 sec. the shock wave travels about 1000 m, in 5 seconds - 2000 m, in 8 seconds. - about 3000 m.
The damaging effects of a shock wave on people and the destructive effect on military equipment, engineering structures and materiel are primarily determined by excess pressure and the speed of air movement in its front. Unprotected people can, in addition, be affected by shards of glass flying at great speed and fragments of destroyed buildings, falling trees, as well as scattered parts of military equipment, clods of earth, stones and other objects set in motion by the high-speed pressure of the shock wave. The greatest indirect damage will be observed in populated areas and forests; in these cases, population losses may be greater than from the direct effect of the shock wave. Damages caused by a shock wave are divided into
1) lungs,
2) average,
3) heavy and
4) extremely heavy.
The degree of damage from a shock wave depends primarily on the power and type of nuclear explosion. In an air explosion with a power of 20 kT, light injuries to people are possible at distances of up to 2.5 km, medium - up to 2 km, severe - up to 1.5 km, extremely severe - up to 1.0 km from the epicenter of the explosion. As the caliber of a nuclear weapon increases, the radius of shock wave damage increases in proportion to the cube root of the explosion power.
Guaranteed protection of people from the shock wave is provided by sheltering them in shelters. In the absence of shelters, natural shelters and terrain are used.
During an underground explosion, a shock wave occurs in the ground, and during an underwater explosion, it occurs in water. The shock wave, propagating in the ground, causes damage to underground structures, sewers, and water pipes; when it spreads in water, damage to the underwater parts of ships located even at a considerable distance from the explosion site is observed.
In relation to civil and industrial buildings, the degree of destruction is characterized by 1) weak,
2) average,
3) strong and 4) complete destruction.
Weak destruction is accompanied by the destruction of window and door fillings and light partitions, the roof is partially destroyed, and cracks are possible in the walls of the upper floors. The basements and lower floors are completely preserved.
Moderate destruction manifests itself in the destruction of roofs, internal partitions, windows, collapse of attic floors, and cracks in walls. Restoration of buildings is possible during major repairs.
Severe destruction is characterized by the destruction of load-bearing structures and ceilings of the upper floors, and the appearance of cracks in the walls. The use of buildings becomes impossible. Repair and restoration of buildings becomes impractical.
With complete destruction, all the main elements of the building collapse, including supporting structures. It is impossible to use such buildings, and so that they do not pose a danger, they are completely collapsed.
It is necessary to note the ability of the shock wave. It can, like water, “flow” into closed spaces not only through windows and doors, but also through small holes and even cracks. This leads to the destruction of partitions and equipment inside the building and injury to the people in it.
Nuclear weapon
Nuclear weapons are a set of nuclear weapons, means of delivering them to the target and control means. Refers to weapons of mass destruction (along with biological and chemical weapons). A nuclear weapon is an explosive device that uses nuclear energy - energy released as a result of an avalanche-like nuclear chain reaction of fission of heavy nuclei and/or thermonuclear fusion reaction of light nuclei.
The action of nuclear weapons is based on the use of the explosion energy of a nuclear explosive device, released as a result of an uncontrolled avalanche-like chain reaction of fission of heavy nuclei and/or thermonuclear fusion reaction.
Nuclear explosions can be of the following types:
· air - in the troposphere
· high-altitude - in the upper layers of the atmosphere and in near-planetary space
· cosmic - in deep circumplanetary space and any other area of outer space
ground explosion - near the ground
· underground explosion (under the surface of the earth)
surface (near the surface of the water)
underwater (underwater)
Damaging factors of a nuclear explosion:
shock wave
light radiation
· penetrating radiation
· radioactive contamination
· electromagnetic pulse (EMP)
The ratio of the power of influence of various damaging factors depends on the specific physics of a nuclear explosion. For example, a thermonuclear explosion is characterized by stronger ones than the so-called. An atomic explosion produces light radiation, a gamma-ray component of penetrating radiation, but a much weaker corpuscular component of penetrating radiation and radioactive contamination of the area.
People directly exposed to the damaging factors of a nuclear explosion, in addition to physical damage, which is often fatal to humans, experience a powerful psychological impact from the terrifying sight of the explosion and destruction. An electromagnetic pulse (EMP) does not have a direct effect on living organisms, but can disrupt the operation of electronic equipment (tube electronics and photonic equipment are relatively insensitive to the effects of EMP).
Classification of nuclear weapons
All nuclear weapons can be divided into two main categories:
· “atomic” - single-phase or single-stage explosive devices in which the main energy output comes from the nuclear reaction of fission of heavy nuclei (uranium-235 or plutonium) with the formation of lighter elements
thermonuclear (also “hydrogen”) - two-phase or two-stage explosive devices in which two physical processes, localized in different areas of space, are sequentially developed: in the first stage, the main source of energy is the fission reaction of heavy nuclei, and in the second, fission and thermonuclear fusion reactions are used in varying proportions, depending on the type and configuration of the ammunition
The power of a nuclear charge is measured in TNT equivalent - the amount of trinitrotoluene that must be detonated to produce the same energy. It is usually expressed in kilotons (kt) and megatons (Mt). The TNT equivalent is conditional: firstly, the distribution of the energy of a nuclear explosion among various damaging factors depends significantly on the type of ammunition, and, in any case, is very different from a chemical explosion. Secondly, it is simply impossible to achieve complete combustion of the appropriate amount of chemical explosive.
It is customary to divide nuclear weapons into five groups according to their power:
· ultra-small (less than 1 kt)
· small (1 - 10 kt)
medium (10 - 100 kt)
· large (high power) (100 kt - 1 Mt)
· extra-large (extra-high power) (over 1 Mt)
Nuclear detonation options
Cannon scheme
The "cannon design" was used in some first generation nuclear weapons. The essence of the cannon circuit is to fire a charge of gunpowder from one block of fissile material of subcritical mass (“bullet”) into another stationary one (“target”).
A classic example of a cannon design is the “Little Boy” bomb, dropped on Hiroshima on August 6, 1945.
Implosive circuit
An implosive detonation scheme uses the compression of fissile material by a focused shock wave created by the detonation of a chemical explosive. To focus the shock wave, so-called explosive lenses are used, and the detonation is carried out simultaneously at many points with high precision. The formation of a converging shock wave was ensured by the use of explosive lenses from “fast” and “slow” explosives - TATV (triaminotrinitrobenzene) and baratol (a mixture of trinitrotoluene with barium nitrate), and some additives (see animation). The creation of such a system for the placement of explosives and detonation was at one time one of the most difficult and time-consuming tasks. To solve it, it was necessary to perform a gigantic amount of complex calculations in hydro- and gas dynamics.
The second of the atomic bombs used, “Fat Man,” dropped on Nagasaki on August 9, 1945, was executed according to the same scheme.
2000 nuclear explosions
The creator of the atomic bomb, Robert Oppenheimer, on the day of the first test of his brainchild said: “If hundreds of thousands of suns rose in the sky at once, their light could be compared with the radiance emanating from the Supreme Lord... I am Death, the great destroyer of the worlds, bringing death to all living things " These words were a quote from the Bhagavad Gita, which the American physicist read in the original.
Photographers from Lookout Mountain stand waist-deep in dust raised by the shock wave after a nuclear explosion (photo from 1953).
Challenge Name: Umbrella
Date: June 8, 1958
Power: 8 kilotons
An underwater nuclear explosion was carried out during Operation Hardtack. Decommissioned ships were used as targets.
Challenge Name: Chama (as part of Project Dominic)
Date: October 18, 1962
Location: Johnston Island
Power: 1.59 megatons
Challenge Name: Oak
Date: June 28, 1958
Location: Enewetak Lagoon in the Pacific Ocean
Yield: 8.9 megatons
Project Upshot Knothole, Annie Test. Date: March 17, 1953; project: Upshot Knothole; challenge: Annie; Location: Knothole, Nevada Test Site, Sector 4; power: 16 kt. (Photo: Wikicommons)
Challenge Name: Castle Bravo
Date: March 1, 1954
Location: Bikini Atoll
Explosion type: surface
Power: 15 megatons
The Castle Bravo hydrogen bomb was the most powerful explosion ever tested by the United States. The power of the explosion turned out to be much greater than the initial forecasts of 4-6 megatons.
Challenge Name: Castle Romeo
Date: March 26, 1954
Location: on a barge in Bravo Crater, Bikini Atoll
Explosion type: surface
Power: 11 megatons
The power of the explosion turned out to be 3 times greater than initial forecasts. Romeo was the first test carried out on a barge.
Project Dominic, Aztec Test
Challenge Name: Priscilla (as part of the "Plumbbob" challenge series)
Date: 1957
Yield: 37 kilotons
This is exactly what the process of releasing huge amounts of radiant and thermal energy looks like during an atomic explosion in the air over the desert. Here you can still see military equipment, which in a moment will be destroyed by the shock wave, captured in the form of a crown surrounding the epicenter of the explosion. You can see how the shock wave was reflected from the earth's surface and is about to merge with the fireball.
Challenge Name: Grable (as part of Operation Upshot Knothole)
Date: May 25, 1953
Location: Nevada Nuclear Test Site
Power: 15 kilotons
At a test site in the Nevada desert, photographers from the Lookout Mountain Center in 1953 took a photograph of an unusual phenomenon (a ring of fire in a nuclear mushroom after the explosion of a shell from a nuclear cannon), the nature of which has long occupied the minds of scientists.
Project Upshot Knothole, Rake test. This test involved an explosion of a 15 kiloton atomic bomb launched by a 280mm atomic cannon. The test took place on May 25, 1953 at the Nevada Test Site. (Photo: National Nuclear Security Administration/Nevada Site Office)
A mushroom cloud formed as a result of the atomic explosion of the Truckee test conducted as part of Project Dominic.
Project Buster, Test Dog.
Project Dominic, Yeso test. Test: Yeso; date: June 10, 1962; project: Dominic; location: 32 km south of Christmas Island; test type: B-52, atmospheric, height - 2.5 m; power: 3.0 mt; charge type: atomic. (Wikicommons)
Challenge Name: YESO
Date: June 10, 1962
Location: Christmas Island
Power: 3 megatons
Testing "Licorn" in French Polynesia. Image #1. (Pierre J./French Army)
Challenge name: “Unicorn” (French: Licorne)
Date: July 3, 1970
Location: Atoll in French Polynesia
Yield: 914 kilotons
Testing "Licorn" in French Polynesia. Image #2. (Photo: Pierre J./French Army)
Testing "Licorn" in French Polynesia. Image #3. (Photo: Pierre J./French Army)
To get good images, test sites often employ entire teams of photographers. Photo: nuclear test explosion in the Nevada desert. On the right are visible rocket plumes, with the help of which scientists determine the characteristics of the shock wave.
Testing "Licorn" in French Polynesia. Image #4. (Photo: Pierre J./French Army)
Project Castle, Romeo Test. (Photo: zvis.com)
Project Hardtack, Umbrella Test. Challenge: Umbrella; date: June 8, 1958; project: Hardtack I; location: Enewetak Atoll lagoon; test type: underwater, depth 45 m; power: 8kt; charge type: atomic.
Project Redwing, Test Seminole. (Photo: Nuclear Weapons Archive)
Riya test. Atmospheric test of an atomic bomb in French Polynesia in August 1971. As part of this test, which took place on August 14, 1971, a thermonuclear warhead codenamed "Riya" with a yield of 1000 kt was detonated. The explosion occurred on the territory of Mururoa Atoll. This photo was taken from a distance of 60 km from the zero mark. Photo: Pierre J.
A mushroom cloud from a nuclear explosion over Hiroshima (left) and Nagasaki (right). During the final stages of World War II, the United States launched two atomic bombs on Hiroshima and Nagasaki. The first explosion occurred on August 6, 1945, and the second on August 9, 1945. This was the only time nuclear weapons were used for military purposes. By order of President Truman, the US Army dropped the Little Boy nuclear bomb on Hiroshima on August 6, 1945, followed by the Fat Man nuclear bomb on Nagasaki on August 9. Within 2-4 months after the nuclear explosions, between 90,000 and 166,000 people died in Hiroshima, and between 60,000 and 80,000 in Nagasaki. (Photo: Wikicommons)
Upshot Knothole Project. Nevada Test Site, March 17, 1953. The blast wave completely destroyed Building No. 1, located at a distance of 1.05 km from the zero mark. The time difference between the first and second shot is 21/3 seconds. The camera was placed in a protective case with a wall thickness of 5 cm. The only light source in this case was a nuclear flash. (Photo: National Nuclear Security Administration/Nevada Site Office)
Project Ranger, 1951. The name of the test is unknown. (Photo: National Nuclear Security Administration/Nevada Site Office)
Trinity Test.
"Trinity" was the code name for the first nuclear weapons test. This test was conducted by the United States Army on July 16, 1945, at a site located approximately 56 km southeast of Socorro, New Mexico, at the White Sands Missile Range. The test used an implosion-type plutonium bomb, nicknamed “The Thing.” After detonation, an explosion occurred with a power equivalent to 20 kilotons of TNT. The date of this test is considered the beginning of the atomic era. (Photo: Wikicommons)
Challenge Name: Mike
Date: October 31, 1952
Location: Elugelab Island ("Flora"), Enewate Atoll
Power: 10.4 megatons
The device detonated during Mike's test, called the "sausage", was the first true megaton-class "hydrogen" bomb. The mushroom cloud reached a height of 41 km with a diameter of 96 km.
AN602 (aka “Tsar Bomba”, aka “Kuzka’s Mother”) is a thermonuclear aerial bomb developed in the USSR in 1954-1961. a group of nuclear physicists under the leadership of Academician of the USSR Academy of Sciences I.V. Kurchatov. The most powerful explosive device in the history of mankind. According to various sources, it had from 57 to 58.6 megatons of TNT equivalent. The bomb was tested on October 30, 1961. (Wikimedia)
The MET bombing carried out as part of Operation Thipot. It is noteworthy that the MET explosion was comparable in power to the Fat Man plutonium bomb dropped on Nagasaki. April 15, 1955, 22 kt. (Wikimedia)
One of the most powerful explosions of a thermonuclear hydrogen bomb in the US account was Operation Castle Bravo. The charge power was 10 megatons. The explosion took place on March 1, 1954 at Bikini Atoll, Marshall Islands. (Wikimedia)
Operation Castle Romeo was one of the most powerful thermonuclear bomb explosions carried out by the United States. Bikini Atoll, March 27, 1954, 11 megatons. (Wikimedia)
Baker explosion, showing the white surface of the water disturbed by the air shock wave, and the top of the hollow column of spray that formed the hemispherical Wilson cloud. In the background is the shore of Bikini Atoll, July 1946. (Wikimedia)
The explosion of the American thermonuclear (hydrogen) bomb “Mike” with a power of 10.4 megatons. November 1, 1952. (Wikimedia)
Operation Greenhouse was the fifth series of American nuclear tests and the second of them in 1951. The operation tested nuclear warhead designs using nuclear fusion to increase energy output. In addition, the impact of the explosion on structures, including residential buildings, factory buildings and bunkers, was studied. The operation was carried out at the Pacific nuclear test site. All devices were detonated on high metal towers, simulating an air explosion. George explosion, 225 kilotons, May 9, 1951. (Wikimedia)
A mushroom cloud with a column of water instead of a dust stalk. To the right, a hole is visible on the pillar: the battleship Arkansas covered the emission of splashes. Baker test, charge power - 23 kilotons of TNT, July 25, 1946. (Wikimedia)
200 meter cloud over Frenchman Flat after the MET explosion as part of Operation Teapot, April 15, 1955, 22 kt. This projectile had a rare uranium-233 core. (Wikimedia)
The crater was formed when a 100-kiloton blast wave was blasted beneath 635 feet of desert on July 6, 1962, displacing 12 million tons of earth. 
Time: 0s. Distance: 0m. Initiation of a nuclear detonator explosion.
Time: 0.0000001s. Distance: 0m Temperature: up to 100 million °C. The beginning and course of nuclear and thermonuclear reactions in a charge. With its explosion, a nuclear detonator creates conditions for the onset of thermonuclear reactions: the thermonuclear combustion zone passes through a shock wave in the charge substance at a speed of about 5000 km/s (106 - 107 m/s). About 90% of the neutrons released during the reactions are absorbed by the bomb substance, the remaining 10% are emitted out.
Time:< 10−7c. Расстояние: 2м Temperature: 30 million°C. The end of the reaction, the beginning of the dispersion of the bomb substance. The bomb immediately disappears from view and in its place a bright luminous sphere (fireball) appears, masking the dispersion of the charge. The growth rate of the sphere in the first meters is close to the speed of light. The density of the substance here drops to 1% of the density of the surrounding air in 0.01 seconds; the temperature drops to 7-8 thousand °C in 2.6 seconds, is held for ~5 seconds and further decreases with the rise of the fiery sphere; After 2-3 seconds the pressure drops to slightly below atmospheric pressure.
Time: 1.1x10−7s. Distance: 10m Temperature: 6 million°C. The expansion of the visible sphere to ~10 m occurs due to the glow of ionized air under X-ray radiation from nuclear reactions, and then through radiative diffusion of the heated air itself. The energy of radiation quanta leaving the thermonuclear charge is such that their free path before being captured by air particles is about 10 m and is initially comparable to the size of a sphere; photons quickly run around the entire sphere, averaging its temperature and fly out of it at the speed of light, ionizing more and more layers of air, hence the same temperature and near-light growth rate. Further, from capture to capture, photons lose energy and their travel distance is reduced, the growth of the sphere slows down.
Time: 1.4x10−7s. Distance: 16m Temperature: 4 million°C. In general, from 10−7 to 0.08 seconds, the 1st phase of the sphere’s glow occurs with a rapid drop in temperature and the release of ~1% of radiation energy, mostly in the form of UV rays and bright light radiation, which can damage the vision of a distant observer without education skin burns. The illumination of the earth's surface at these moments at distances of up to tens of kilometers can be a hundred or more times greater than the sun.
Time: 1.7x10−7s. Distance: 21m Temperature: 3 million°C. Bomb vapors in the form of clubs, dense clots and jets of plasma, like a piston, compress the air in front of them and form a shock wave inside the sphere - an internal shock wave, which differs from an ordinary shock wave in non-adiabatic, almost isothermal properties and at the same pressures is several times higher in density: shock-compressing the air immediately radiates most of the energy through the ball, which is still transparent to radiation.
In the first tens of meters, the surrounding objects, before the fire sphere hits them, due to its too high speed, do not have time to react in any way - they even practically do not heat up, and once inside the sphere under the flow of radiation they evaporate instantly.
Temperature: 2 million°C. Speed 1000 km/s. As the sphere grows and the temperature drops, the energy and flux density of photons decrease and their range (on the order of a meter) is no longer enough for near-light speeds of expansion of the fire front. The heated volume of air began to expand and a flow of its particles was formed from the center of the explosion. When the air is still at the boundary of the sphere, the heat wave slows down. The expanding heated air inside the sphere collides with the stationary air at its boundary, and somewhere starting from 36-37 m, a wave of increasing density appears - the future external air shock wave; Before this, the wave did not have time to appear due to the enormous growth rate of the light sphere.
Time: 0.000001s. Distance: 34m Temperature: 2 million°C. The internal shock and vapors of the bomb are located in a layer 8-12 m from the explosion site, the pressure peak is up to 17,000 MPa at a distance of 10.5 m, the density is ~ 4 times the density of air, the speed is ~ 100 km/s. Hot air region: pressure at the boundary 2,500 MPa, inside the region up to 5000 MPa, particle speed up to 16 km/s. The substance of the bomb vapor begins to lag behind the internals. jump as more and more air in it is drawn into motion. Dense clots and jets maintain speed.
Time: 0.000034s. Distance: 42m Temperature: 1 million°C. Conditions at the epicenter of the explosion of the first Soviet hydrogen bomb (400 kt at a height of 30 m), which created a crater about 50 m in diameter and 8 m deep. At 15 m from the epicenter or 5-6 m from the base of the tower with the charge there was a reinforced concrete bunker with walls 2 m thick. For placing scientific equipment on top, covered with a large mound of earth 8 m thick, destroyed.
Temperature: 600 thousand °C. From this moment, the nature of the shock wave ceases to depend on the initial conditions of a nuclear explosion and approaches the typical one for a strong explosion in the air, i.e. Such wave parameters could be observed during the explosion of a large mass of conventional explosives.
Time: 0.0036s. Distance: 60m Temperature: 600 thousand°C. The internal shock, having passed the entire isothermal sphere, catches up and merges with the external one, increasing its density and forming the so-called. a strong shock is a single shock wave front. The density of matter in the sphere drops to 1/3 atmospheric.
Time: 0.014s. Distance: 110m Temperature: 400 thousand°C. A similar shock wave at the epicenter of the explosion of the first Soviet atomic bomb with a power of 22 kt at a height of 30 m generated a seismic shift that destroyed the imitation of metro tunnels with various types of fastening at depths of 10 and 20 m. 30 m, animals in the tunnels at depths of 10, 20 and 30 m died . An inconspicuous saucer-shaped depression with a diameter of about 100 m appeared on the surface. Similar conditions were at the epicenter of the Trinity explosion of 21 kt at an altitude of 30 m; a crater with a diameter of 80 m and a depth of 2 m was formed.
Time: 0.004s. Distance: 135m
Temperature: 300 thousand°C. The maximum height of the air explosion is 1 Mt to form a noticeable crater in the ground. The front of the shock wave is distorted by the impacts of bomb vapor clumps:
Time: 0.007s. Distance: 190m Temperature: 200 thousand°C. On a smooth and seemingly shiny front, the beat. waves form large blisters and bright spots (the sphere seems to be boiling). The density of matter in an isothermal sphere with a diameter of ~150 m drops below 10% of the atmospheric one.
Non-massive objects evaporate a few meters before the arrival of fire. spheres (“Rope tricks”); the human body on the side of the explosion will have time to char, and will completely evaporate with the arrival of the shock wave.
Time: 0.015s. Distance: 250m Temperature: 170 thousand°C. The shock wave greatly destroys rocks. The speed of the shock wave is higher than the speed of sound in metal: the theoretical limit of strength of the entrance door to the shelter; the tank flattens and burns.
Time: 0.028s. Distance: 320m Temperature: 110 thousand°C. The person is dispelled by a stream of plasma (shock wave speed = speed of sound in the bones, the body collapses into dust and immediately burns). Complete destruction of the most durable above-ground structures.
Time: 0.073s. Distance: 400m Temperature: 80 thousand°C. Irregularities on the sphere disappear. The density of the substance drops in the center to almost 1%, and at the edge of the isotherms. spheres with a diameter of ~320 m to 2% atmospheric. At this distance, within 1.5 s, heating to 30,000 °C and dropping to 7000 °C, ~5 s holding at a level of ~6,500 °C and decreasing the temperature in 10-20 s as the fireball moves upward.
Time: 0.079s. Distance: 435m Temperature: 110 thousand°C. Complete destruction of highways with asphalt and concrete surfaces. Temperature minimum of shock wave radiation, end of the 1st phase of glow. A metro-type shelter, lined with cast iron tubes and monolithic reinforced concrete and buried to 18 m, is calculated to be able to withstand an explosion (40 kt) without destruction at a height of 30 m at a minimum distance of 150 m (shock wave pressure of the order of 5 MPa), 38 kt of RDS have been tested. 2 at a distance of 235 m (pressure ~1.5 MPa), received minor deformations and damage. At temperatures in the compression front below 80 thousand °C, new NO2 molecules no longer appear, the layer of nitrogen dioxide gradually disappears and ceases to screen internal radiation. The impact sphere gradually becomes transparent and through it, as through darkened glass, clouds of bomb vapor and the isothermal sphere are visible for some time; In general, the fire sphere is similar to fireworks. Then, as transparency increases, the intensity of the radiation increases and the details of the sphere, as if flaring up again, become invisible. The process is reminiscent of the end of the era of recombination and the birth of light in the Universe several hundred thousand years after the Big Bang.
Time: 0.1s. Distance: 530m Temperature: 70 thousand°C. When the shock wave front separates and moves forward from the boundary of the fire sphere, its growth rate noticeably decreases. The 2nd phase of the glow begins, less intense, but two orders of magnitude longer, with the release of 99% of the explosion radiation energy mainly in the visible and IR spectrum. In the first hundred meters, a person does not have time to see the explosion and dies without suffering (human visual reaction time is 0.1 - 0.3 s, reaction time to a burn is 0.15 - 0.2 s).
Time: 0.15s. Distance: 580m Temperature: 65 thousand°C. Radiation ~100,000 Gy. A person is left with charred bone fragments (the speed of the shock wave is on the order of the speed of sound in soft tissues: a hydrodynamic shock that destroys cells and tissue passes through the body).
Time: 0.25s. Distance: 630m Temperature: 50 thousand°C. Penetrating radiation ~40,000 Gy. A person turns into charred wreckage: the shock wave causes traumatic amputation, which occurs in a fraction of a second. the fiery sphere chars the remains. Complete destruction of the tank. Complete destruction of underground cable lines, water pipelines, gas pipelines, sewers, inspection wells. Destruction of underground reinforced concrete pipes with a diameter of 1.5 m and a wall thickness of 0.2 m. Destruction of the arched concrete dam of a hydroelectric power station. Severe destruction of long-term reinforced concrete fortifications. Minor damage to underground metro structures.
Time: 0.4s. Distance: 800m Temperature: 40 thousand°C. Heating objects up to 3000 °C. Penetrating radiation ~20,000 Gy. Complete destruction of all civil defense protective structures (shelters) and destruction of protective devices at metro entrances. Destruction of the gravity concrete dam of a hydroelectric power station, bunkers become ineffective at a distance of 250 m.
Time: 0.73s. Distance: 1200m Temperature: 17 thousand°C. Radiation ~5000 Gy. With an explosion height of 1200 m, the heating of the ground air at the epicenter before the arrival of the shock. waves up to 900°C. A person is 100% killed by the shock wave. Destruction of shelters designed for 200 kPa (type A-III or class 3). Complete destruction of prefabricated reinforced concrete bunkers at a distance of 500 m under the conditions of a ground explosion. Complete destruction of the railway tracks. The maximum brightness of the second phase of the sphere's glow by this time it had released ~20% of light energy
Time: 1.4s. Distance: 1600m Temperature: 12 thousand°C. Heating objects up to 200°C. Radiation 500 Gy. Numerous 3-4 degree burns up to 60-90% of the body surface, severe radiation damage combined with other injuries, mortality immediately or up to 100% in the first day. The tank is thrown back ~10 m and damaged. Complete destruction of metal and reinforced concrete bridges with a span of 30 - 50 m.
Time: 1.6s. Distance: 1750m Temperature: 10 thousand°C. Radiation approx. 70 Gr. The tank crew dies within 2-3 weeks from extremely severe radiation sickness. Complete destruction of concrete, reinforced concrete monolithic (low-rise) and earthquake-resistant buildings of 0.2 MPa, built-in and free-standing shelters designed for 100 kPa (type A-IV or class 4), shelters in the basements of multi-story buildings.
Time: 1.9c. Distance: 1900m Temperature: 9 thousand °C Dangerous damage to a person by the shock wave and throw up to 300 m with an initial speed of up to 400 km/h, of which 100-150 m (0.3-0.5 path) is free flight, and the remaining distance is numerous ricochets about the ground. Radiation of about 50 Gy is a fulminant form of radiation sickness[, 100% mortality within 6-9 days. Destruction of built-in shelters designed for 50 kPa. Severe destruction of earthquake-resistant buildings. Pressure 0.12 MPa and higher - all urban buildings are dense and discharged and turn into solid rubble (individual rubbles merge into one solid one), the height of the rubble can be 3-4 m. The fire sphere at this time reaches its maximum size (D ~ 2 km), crushed from below by the shock wave reflected from the ground and begins to rise; the isothermal sphere in it collapses, forming a rapid upward flow at the epicenter - the future leg of the mushroom.
Time: 2.6s. Distance: 2200m Temperature: 7.5 thousand°C. Severe injuries to a person by a shock wave. Radiation ~10 Gy is an extremely severe acute radiation sickness, with a combination of injuries, 100% mortality within 1-2 weeks. Safe stay in a tank, in a fortified basement with a reinforced reinforced concrete ceiling and in most G.O. shelters. Destruction of trucks. 0.1 MPa is the design pressure of the shock wave for the design of structures and protective devices for underground structures of shallow subway lines.
Time: 3.8c. Distance: 2800m Temperature: 7.5 thousand°C. Radiation of 1 Gy - in peaceful conditions and timely treatment, a non-hazardous radiation injury, but with the unsanitary conditions and severe physical and psychological stress accompanying the disaster, lack of medical care, nutrition and normal rest, up to half of the victims die only from radiation and concomitant diseases, and in terms of the amount of damage ( plus injuries and burns) much more. Pressure less than 0.1 MPa - urban areas with dense buildings turn into solid rubble. Complete destruction of basements without reinforcement of structures 0.075 MPa. The average destruction of earthquake-resistant buildings is 0.08-0.12 MPa. Severe damage to prefabricated reinforced concrete bunkers. Detonation of pyrotechnics.
Time: 6c. Distance: 3600m Temperature: 4.5 thousand°C. Moderate damage to a person by a shock wave. Radiation ~0.05 Gy - the dose is not dangerous. People and objects leave “shadows” on the asphalt. Complete destruction of administrative multi-storey frame (office) buildings (0.05-0.06 MPa), shelters of the simplest type; severe and complete destruction of massive industrial structures. Almost all urban buildings were destroyed with the formation of local rubble (one house - one rubble). Complete destruction of passenger cars, complete destruction of the forest. An electromagnetic pulse of ~3 kV/m affects insensitive electrical appliances. The destruction is similar to an earthquake 10 points. The sphere turned into a fiery dome, like a bubble floating up, carrying with it a column of smoke and dust from the surface of the earth: a characteristic explosive mushroom grows with an initial vertical speed of up to 500 km/h. Wind speed at the surface to the epicenter is ~100 km/h.
Time: 10c. Distance: 6400m Temperature: 2 thousand°C. The end of the effective time of the second glow phase, ~80% of the total energy of light radiation has been released. The remaining 20% light up harmlessly for about a minute with a continuous decrease in intensity, gradually being lost in the clouds. Destruction of the simplest type of shelter (0.035-0.05 MPa). In the first kilometers, a person will not hear the roar of the explosion due to hearing damage from the shock wave. A person is thrown back by a shock wave of ~20 m with an initial speed of ~30 km/h. Complete destruction of multi-storey brick houses, panel houses, severe destruction of warehouses, moderate destruction of frame administrative buildings. The destruction is similar to a magnitude 8 earthquake. Safe in almost any basement.
The glow of the fiery dome ceases to be dangerous, it turns into a fiery cloud, growing in volume as it rises; hot gases in the cloud begin to rotate in a torus-shaped vortex; the hot products of the explosion are localized in the upper part of the cloud. The flow of dusty air in the column moves twice as fast as the rise of the “mushroom”, overtakes the cloud, passes through, diverges and, as it were, is wound around it, as if on a ring-shaped coil.
Time: 15c. Distance: 7500m. Light damage to a person by a shock wave. Third degree burns to exposed parts of the body. Complete destruction of wooden houses, severe destruction of brick multi-storey buildings 0.02-0.03 MPa, average destruction of brick warehouses, multi-storey reinforced concrete, panel houses; weak destruction of administrative buildings 0.02-0.03 MPa, massive industrial structures. Cars catching fire. The destruction is similar to a magnitude 6 earthquake or a magnitude 12 hurricane. up to 39 m/s. The “mushroom” has grown up to 3 km above the center of the explosion (the true height of the mushroom is greater than the height of the warhead explosion, about 1.5 km), it has a “skirt” of condensation of water vapor in a stream of warm air, fanned by the cloud into the cold upper layers atmosphere.
Time: 35c. Distance: 14km. Second degree burns. Paper and dark tarpaulin ignite. A zone of continuous fires; in areas of densely combustible buildings, a fire storm and tornado are possible (Hiroshima, “Operation Gomorrah”). Weak destruction of panel buildings. Disablement of aircraft and missiles. The destruction is similar to an earthquake of 4-5 points, a storm of 9-11 points V = 21 - 28.5 m/s. The “mushroom” has grown to ~5 km; the fiery cloud is shining more and more faintly.
Time: 1 min. Distance: 22km. First-degree burns—wearing beachwear can cause death. Destruction of reinforced glazing. Uprooting large trees. Zone of individual fires. The “mushroom” has risen to 7.5 km, the cloud stops emitting light and now has a reddish tint due to the nitrogen oxides it contains, which will make it stand out sharply among other clouds.
Time: 1.5 min. Distance: 35km. The maximum radius of damage to unprotected sensitive electrical equipment by an electromagnetic pulse. Almost all the regular glass and some of the reinforced glass in the windows were broken—especially in the frosty winter, plus the possibility of cuts from flying fragments. “Mushroom” rose to 10 km, ascent speed ~220 km/h. Above the tropopause, the cloud develops predominantly in width.
Time: 4min. Distance: 85km. The flash looks like a large, unnaturally bright Sun on the horizon and can cause a burn to the retina and a rush of heat to the face. The shock wave arriving after 4 minutes can still knock a person off his feet and break individual glass in the windows. “Mushroom” rose over 16 km, ascent speed ~140 km/h
Time: 8 min. Distance: 145km. The flash is not visible beyond the horizon, but a strong glow and a fiery cloud are visible. The total height of the “mushroom” is up to 24 km, the cloud is 9 km in height and 20-30 km in diameter, with its widest part “resting” on the tropopause. The mushroom cloud has grown to its maximum size and is observed for about an hour or more until it is dissipated by the winds and mixed with normal clouds. Precipitation with relatively large particles falls out of the cloud within 10-20 hours, forming a near radioactive trace.
Time: 5.5-13 hours Distance: 300-500 km. The far border of the moderately infected zone (zone A). The radiation level at the outer boundary of the zone is 0.08 Gy/h; total radiation dose 0.4-4 Gy.
Time: ~10 months. The effective time of half-deposition of radioactive substances for the lower layers of the tropical stratosphere (up to 21 km); fallout also occurs mainly in the middle latitudes in the same hemisphere where the explosion occurred.
Monument to the first test of the Trinity atomic bomb. This monument was erected at the White Sands test site in 1965, 20 years after the Trinity test. The monument's plaque reads: "The world's first atomic bomb test took place at this site on July 16, 1945." Another plaque below commemorates the site's designation as a National Historic Landmark. (Photo: Wikicommons)
A nuclear explosion is an uncontrollable process. During it, a large amount of radiant and thermal energy is released. This effect is the result of a nuclear chain reaction of fission or thermonuclear fusion occurring over a short period of time.
Brief general information
A nuclear explosion, by its origin, can be a consequence of human activity on Earth or in near-Earth space. This phenomenon also in some cases occurs as a result of natural processes on certain types of stars. An artificial nuclear explosion is a powerful weapon. It is used to destroy large-scale ground and underground protected objects, accumulations of enemy equipment and troops. In addition, this weapon is used for the complete destruction and suppression of the opposing side as a tool that destroys small and large settlements with civilians living in them, as well as strategic industrial facilities.
Classification
As a rule, nuclear explosions are characterized by two criteria. These include the charge power and the location of the charge point directly at the blasting moment. The projection of this point onto the surface of the earth is called the epicenter of the explosion. Power is measured in TNT equivalent. This is the mass of trinitrotoluene, the detonation of which releases the same amount of energy as the estimated nuclear explosion. The most commonly used units when measuring power are one kiloton (1 kt) and one megaton (1 Mt) of TNT equivalent.
Phenomena
A nuclear explosion is accompanied by specific effects. They are characteristic only of this process and are not present in other explosions. The intensity of the phenomena that accompany a nuclear explosion depends on the location of the center. As an example, we can consider the case that was the most common before the ban on testing on the planet (under water, on land, in the atmosphere) and, in fact, in space - an artificial chain reaction in the ground layer. After the detonation of the fusion or fission process, in a very short time (about fractions of microseconds), a huge amount of thermal and radiant energy is released in a limited volume. The completion of the reaction is usually indicated by the disintegration of the device structure and evaporation. These effects are due to the influence of elevated temperature (up to 107 K) and enormous pressure (about 109 atm) at the epicenter itself. From a great distance, this phase visually appears as a very bright luminous point.
Electromagnetic radiation
Light pressure during the reaction begins to heat and displace the surrounding air from the epicenter. As a result, a fireball is formed. At the same time, a pressure jump is formed between the compressed radiation and undisturbed air. This is due to the superiority of the speed of movement of the heating front over the sound speed under environmental conditions. After the nuclear reaction enters the decay stage, the release of energy stops. Subsequent expansion is carried out due to the difference in pressure and temperature in the zone of the fireball and the immediate surrounding air. It should be noted that the phenomena under consideration have nothing to do with the scientific research of the hero of the modern TV series (by the way, his name is the same as the famous physicist Glashow - Sheldon) “The Big Bang Theory”.
Penetrating radiation
Nuclear reactions are a source of electromagnetic radiation of various types. In particular, it manifests itself in a wide spectrum ranging from radio waves to gamma rays, atomic nuclei, neutrons, and fast electrons. The emerging radiation, called penetrating radiation, in turn, gives rise to certain consequences. They are characteristic only of a nuclear explosion. High-energy gamma quanta and neutrons, in the process of interaction with atoms that make up the surrounding matter, undergo the transformation of their stable form into unstable radioactive isotopes with different half-lives and paths. As a result, so-called induced radiation is formed. Together with fragments of atomic nuclei of fissile matter or with products from thermonuclear fusion that remain from an explosive device, the resulting radioactive components rise into the atmosphere. Then they disperse over a fairly large area and form an infestation in the area. The unstable isotopes that accompany a nuclear explosion are in such a spectrum that the spread of radiation can continue for millennia, even though the intensity of the radiation decreases over time.
Electromagnetic pulse
High-energy gamma quanta generated from a nuclear explosion, in the process of passing through the environment, ionize the atoms that make up its composition, knocking out electrons from them and imparting to them quite a large energy to carry out the cascade ionization of other atoms (up to thirty thousand ionizations per gamma quanta). As a result, a “spot” of ions with a positive charge and surrounded by electron gas in huge quantities is formed under the epicenter. This configuration of carriers, variable in time, forms a powerful electric field. It, together with the recombination of ionized atomic particles, disappears after the explosion. The process generates strong electrical currents. They serve as an additional source of radiation. The entire described complex of effects is called an electromagnetic pulse. Despite the fact that less than 1/3 of a ten-billionth of the explosive energy goes into it, it occurs over a very short period. The power released in this case can reach 100 GW.
Ground-type processes. Peculiarities
During the process of chemical detonation, the temperature of the soil adjacent to the charge and attracted to the movement is relatively low. A nuclear explosion has its own characteristics. In particular, the ground temperature can be tens of millions of degrees. Most of the energy generated from heating is released into the air during the first moments and is additionally used to form a shock wave and thermal radiation. In a normal explosion, these phenomena are not observed. In this regard, there are sharp differences in the impact on the soil mass and the surface. During a ground explosion of a chemical compound, up to half of the energy is transferred to the ground, and during a nuclear explosion, literally a few percent. This causes the difference in the size of the crater and the energy of seismic vibrations.
Nuclear winter
This concept characterizes the hypothetical state of the climate on the planet in the event of a large-scale war using nuclear weapons. Presumably, due to the release of a huge amount of soot and smoke into the stratosphere, the results of numerous fires provoked by several warheads, the temperature on Earth will drop everywhere to Arctic levels. This will also be due to a significant increase in the number of solar rays reflected from the surface. The likelihood of global cooling was predicted quite a long time ago (even during the existence of the Soviet Union). Later, the hypothesis was confirmed by model calculations.
3.2. Nuclear explosions
3.2.1. Classification of nuclear explosions
Nuclear weapons were developed in the USA during World War II mainly through the efforts of European scientists (Einstein, Bohr, Fermi, etc.). The first test of this weapon took place in the United States at the Alamogordo training ground on July 16, 1945 (at that time the Potsdam Conference was taking place in defeated Germany). And only 20 days later, on August 6, 1945, an atomic bomb of colossal power for that time - 20 kilotons - was dropped on the Japanese city of Hiroshima, without any military necessity or expediency. Three days later, on August 9, 1945, the second Japanese city, Nagasaki, was subjected to atomic bombing. The consequences of nuclear explosions were terrible. In Hiroshima, with 255 thousand inhabitants, almost 130 thousand people were killed or wounded. Of the nearly 200 thousand inhabitants of Nagasaki, over 50 thousand people were affected.
Then nuclear weapons were manufactured and tested in the USSR (1949), Great Britain (1952), France (1960), and China (1964). Currently, more than 30 states of the world are ready scientifically and technically for the production of nuclear weapons.
There are now nuclear charges that use the fission reaction of uranium-235 and plutonium-239 and thermonuclear charges that use (at the time of explosion) the fusion reaction. When one neutron is captured, the uranium-235 nucleus splits into two fragments, releasing gamma rays and two more neutrons (2.47 neutrons for uranium-235 and 2.91 neutrons for plutonium-239). If the mass of uranium is more than a third, then these two neutrons divide two more nuclei, releasing four neutrons. After the next four nuclei split, eight neutrons are released, and so on. A chain reaction occurs that leads to a nuclear explosion.
Classification of nuclear explosions:
By charge type:
- nuclear (atomic) - fission reaction;
- thermonuclear - fusion reaction;
- neutron - high neutron flux;
- combined.
By purpose:
Testing;
For peaceful purposes;
- for military purposes;
By power:
- ultra-small (less than 1 thousand tons of TNT);
- small (1 - 10 thousand tons);
- medium (10-100 thousand tons);
- large (100 thousand tons -1 Mt);
- extra-large (over 1 Mt).
By type of explosion:
- high-altitude (over 10 km);
- airborne (the light cloud does not reach the Earth's surface);
Ground;
Surface;
Underground;
Underwater.
Damaging factors of a nuclear explosion. The damaging factors of a nuclear explosion are:
- shock wave (50% explosion energy);
- light radiation (35% of explosion energy);
- penetrating radiation (45% of explosion energy);
- radioactive contamination (10% of explosion energy);
- electromagnetic pulse (1% explosion energy);
Shock wave (SW) (50% of explosion energy). UX is a zone of strong air compression that spreads at supersonic speed in all directions from the center of the explosion. The source of the shock wave is the high pressure at the center of the explosion, reaching 100 billion kPa. Explosion products, as well as very heated air, expand and compress the surrounding air layer. This compressed layer of air compresses the next layer. Thus, pressure is transferred from one layer to another, creating HC. The leading edge of compressed air is called the front of the compressed air.
The main parameters of the control system are:
- overpressure;
- velocity pressure;
- duration of the shock wave.
Excess pressure is the difference between the maximum pressure at the front of the air pressure and atmospheric pressure.
G f =G f.max -P 0
It is measured in kPa or kgf/cm2 (1 agm = 1.033 kgf/cm2 = 101.3 kPa; 1 atm = 100 kPa).
The value of overpressure mainly depends on the power and type of explosion, as well as on the distance to the center of the explosion.
It can reach 100 kPa in explosions with a power of 1 mt or more.
Excess pressure decreases rapidly with distance from the epicenter of the explosion.
Velocity air pressure is a dynamic load that creates air flow, denoted by P, measured in kPa. The magnitude of the air velocity pressure depends on the speed and density of the air behind the wave front and is closely related to the value of the maximum excess pressure of the shock wave. The velocity head has a noticeable effect at excess pressure above 50 kPa.
The duration of the shock wave (overpressure) is measured in seconds. The longer the duration of action, the greater the damaging effect of the chemical agent. The explosive effect of a nuclear explosion of average power (10-100 kt) travels 1000 m in 1.4 s, 2000 m in 4 s; 5000 m - in 12 s. UD affects people and destroys buildings, structures, objects and communication equipment.
The shock wave affects unprotected people directly and indirectly (indirect damage is damage that is inflicted on a person by fragments of buildings, structures, glass fragments and other objects that move at high speed under the influence of high-speed air pressure). Injuries that occur due to the action of a shock wave are divided into:
- light, typical for the Russian Federation = 20 - 40 kPa;
- /span> average, typical for the Russian Federation = 40 - 60 kPa:
- heavy, characteristic of the Russian Federation = 60 - 100 kPa;
- very heavy, typical for the Russian Federation above 100 kPa.
In an explosion with a power of 1 Mt, unprotected people can receive minor injuries, being 4.5 - 7 km from the epicenter of the explosion, and severe ones - 2 - 4 km.
To protect against chemical pollution, special storage facilities are used, as well as basements, underground workings, mines, natural shelters, terrain folds, etc.
The volume and nature of destruction of buildings and structures depends on the power and type of explosion, the distance from the epicenter of the explosion, the strength and size of buildings and structures. Of the above-ground buildings and structures, the most resistant are monolithic reinforced concrete structures, houses with a metal frame and buildings of anti-seismic design. In a nuclear explosion with a power of 5 Mt, reinforced concrete structures will be destroyed within a radius of 6.5 km, brick houses - up to 7.8 km, wooden houses will be completely destroyed within a radius of 18 km.
Carbon dioxide has the ability to penetrate into rooms through window and door openings, causing destruction of partitions and equipment. Technological equipment is more stable and is destroyed mainly as a result of the collapse of walls and ceilings of the houses in which it is installed.
Light radiation (35% of explosion energy). Light radiation (LW) is electromagnetic radiation in the ultraviolet, visible and infrared regions of the spectrum. The source of SW is a luminous region that propagates at the speed of light (300,000 km/s). The lifetime of the luminous area depends on the power of the explosion and is for charges of various calibers: super-small caliber - tenths of a second, medium - 2 - 5 s, extra-large - several tens of seconds. The size of the luminous area for the super-small caliber is 50-300 m, for the medium 50 - 1000 m, for the super-large caliber - several kilometers.
The main parameter characterizing the SW is the light pulse. It is measured in calories per 1 cm2 of surface located perpendicular to the direction of direct radiation, as well as in kilojoules per m2:
1 cal/cm2 = 42 kJ/m2.
Depending on the magnitude of the perceived light pulse and the depth of damage to the skin, a person experiences burns of three degrees:
- 1st degree burns are characterized by skin redness, swelling, pain, and are caused by a light pulse of 100-200 kJ/m 2 ;
- Second degree burns (blisters) occur with a light pulse of 200...400 kJ/m 2;
- III degree burns (ulcers, skin necrosis) appear at a light pulse value of 400-500 kJ/m 2 .
A large impulse value (more than 600 kJ/m2) causes charring of the skin.
During a nuclear explosion, 20 kt of degree I will be observed within a radius of 4.0 km, degree 11 - within 2.8 kt, degree III - within a radius of 1.8 km.
With an explosion power of 1 Mt, these distances increase to 26.8 km, 18.6 km, and 14.8 km. respectively.
SW propagates in a straight line and does not pass through opaque materials. Therefore, any obstacle (wall, forest, armor, thick fog, hills, etc.) can form a shadow zone and protects from light radiation.
The strongest effect of SW is fires. The size of fires is influenced by factors such as the nature and condition of the built environment.
When the building density is over 20%, fires can merge into one continuous fire.
Fire losses in World War II amounted to 80%. During the famous bombing of Hamburg, 16 thousand houses were simultaneously set on fire. The temperature in the area of the fires reached 800°C.
SV significantly enhances the effect of HC.
Penetrating radiation (45% of the explosion energy) is caused by radiation and neutron flux that spreads several kilometers around the nuclear explosion, ionizing the atoms of this environment. The degree of ionization depends on the radiation dose, the unit of measurement of which is the x-ray (about two billion ion pairs are formed in 1 cm of dry air at a temperature and pressure of 760 mm Hg). The ionizing ability of neutrons is assessed in environmental equivalents of x-rays (rem - the dose of neutrons, the influence of which is equal to the influence of x-ray radiation).
The effect of penetrating radiation on people causes radiation sickness. Radiation sickness of the 1st degree (general weakness, nausea, dizziness, drowsiness) develops mainly at a dose of 100 - 200 rad.
Radiation sickness of the second degree (vomiting, severe headache) occurs at a dose of 250-400 councils.
Radiation sickness of the third degree (50% dies) develops at a dose of 400 - 600 rad.
Radiation sickness of the IV degree (mostly death occurs) occurs when exposed to more than 600 doses of radiation.
In low-power nuclear explosions, the influence of penetrating radiation is greater than that of carbon dioxide and light irradiation. As the explosion power increases, the relative proportion of damage from penetrating radiation decreases as the number of injuries and burns increases. The radius of damage by penetrating radiation is limited to 4 - 5 km. regardless of the increase in explosion power.
Penetrating radiation significantly affects the efficiency of electronic equipment and communication systems. Pulsed radiation and neutron flux disrupt the functioning of many electronic systems, especially those operating in pulse mode, causing interruptions in power supply, short circuits in transformers, increased voltage, distortion of the shape and magnitude of electrical signals.
In this case, radiation causes temporary interruptions in the operation of equipment, and the neutron flux causes irreversible changes.
For diodes with a flux density of 1011 (germanium) and 1012 (silicon) neutrons/em 2, the characteristics of the forward and reverse currents change.
In transistors, the current gain decreases and the reverse collector current increases. Silicon transistors are more stable and retain their strengthening properties at neutron fluxes above 1014 neutrons/cm 2 .
Electrovacuum devices are stable and retain their properties up to a flux density of 571015 - 571016 neutrons/cm2.
Resistors and capacitors are resistant to a density of 1018 neutrons/cm 2. Then the conductivity of resistors changes, and leakages and losses of capacitors increase, especially for electrical capacitors.
Radioactive contamination (up to 10% of the energy of a nuclear explosion) occurs through induced radiation, the fall of fission fragments of a nuclear charge and parts of residual uranium-235 or plutonium-239 onto the ground.
Radioactive contamination of an area is characterized by the level of radiation, which is measured in roentgens per hour.
The fallout of radioactive substances continues as the radioactive cloud moves under the influence of the wind, as a result of which a radioactive trace is formed on the surface of the earth in the form of a strip of contaminated terrain. The length of the trail can reach several tens of kilometers and even hundreds of kilometers, and the width can reach tens of kilometers.
Depending on the degree of infection and the possible consequences of radiation, 4 zones are distinguished: moderate, severe, dangerous and extremely dangerous.
For the convenience of solving the problem of assessing the radiation situation, zone boundaries are usually characterized by radiation levels at 1 hour after the explosion (P a) and 10 hours after the explosion, P 10. The values of gamma radiation doses D are also established, which are received from 1 hour after the explosion until the complete decay of radioactive substances.
Zone of moderate infection (zone A) - D = 40.0-400 rad. The radiation level at the outer boundary of the zone G in = 8 R/h, R 10 = 0.5 R/h. In zone A, work on objects, as a rule, does not stop. In open areas located in the middle of the zone or at its internal border, work stops for several hours.
Heavy infection zone (zone B) - D = 4000-1200 tips. The radiation level at the outer boundary of G in = 80 R/h, R 10 = 5 R/h. Work stops for 1 day. People are hiding in shelters or evacuating.
Dangerous contamination zone (zone B) - D = 1200 - 4000 rad. The radiation level at the outer boundary of G in = 240 R/h, R 10 = 15 R/h. In this zone, work on sites stops from 1 to 3-4 days. People are evacuating or taking shelter in protective structures.
Extremely dangerous contamination zone (zone D) on the outer border D = 4000 rad. Radiation levels G in = 800 R/h, R 10 = 50 R/h. Work stops for several days and resumes after the radiation level drops to a safe value.
For example in Fig. Figure 23 shows the dimensions of zones A, B, C, D, which are formed during an explosion with a power of 500 kt and a wind speed of 50 km/h.
A characteristic feature of radioactive contamination during nuclear explosions is a relatively rapid decline in radiation levels.
The height of the explosion has a great influence on the nature of the contamination. During high-altitude explosions, the radioactive cloud rises to a considerable height, is blown away by the wind and disperses over a large area.
Table
Dependence of radiation level on time after explosion
| Time after explosion, hours | ||||||||||||||||||||||||||||
| Radiation level, % | 43,5 | 27,0 | 19,0 | 14,5 | 11,6 | 7,15 | 5,05 | 0,96 |
||||||||||||||||||||
Staying people in contaminated areas causes them to be exposed to radioactive substances. In addition, radioactive particles can enter the body, settle on open areas of the body, penetrate into the blood through wounds and scratches, causing varying degrees of radiation sickness.
For wartime conditions, the following doses are considered a safe dose of total single exposure: within 4 days - no more than 50 rads, 10 days - no more than 100 rads, 3 months - 200 rads, per year - no more than 300 rads.
To work in contaminated areas, personal protective equipment is used; when leaving the contaminated area, decontamination is carried out, and people are subject to sanitary treatment.
Shelters and shelters are used to protect people. Each building is assessed by the attenuation coefficient K service, which is understood as a number indicating how many times the radiation dose in the storage facility is less than the radiation dose in an open area. For stone houses, for dishes - 10, for cars - 2, for tanks - 10, for basements - 40, for specially equipped storage facilities it can be even larger (up to 500).
An electromagnetic pulse (EMI) (1% of the explosion energy) is a short-term surge in the voltage of electric and magnetic fields and currents due to the movement of electrons from the center of the explosion, resulting from the ionization of air. The amplitude of EMI decreases exponentially very quickly. The pulse duration is equal to a hundredth of a microsecond (Fig. 25). After the first pulse, due to the interaction of electrons with the Earth’s magnetic field, a second, longer pulse appears.
The frequency range of EMR is up to 100 m Hz, but its energy is mainly distributed near the mid-frequency range of 10-15 kHz. The destructive effect of EMI is several kilometers from the center of the explosion. Thus, for a ground explosion with a power of 1 Mt, the vertical component of the electric field is EMI at a distance of 2 km. from the center of the explosion - 13 kV/m, at 3 km - 6 kV/m, 4 km - 3 kV/m.
EMI does not directly affect the human body.
When assessing the impact of EMI on electronic equipment, simultaneous exposure to EMI radiation must also be taken into account. Under the influence of radiation, the conductivity of transistors and microcircuits increases, and under the influence of EMI, they break down. EMI is extremely effective in damaging electronic equipment. The SDI program provides for special explosions that create EMI sufficient to destroy electronics.