Global problems are an objective result of human development. The fate of civilization depends on the solution of these planetary problems. Today there is a large number of problems that are considered to be global, but all scientists agree that the super-problem is the prevention nuclear war and the preservation of the world.
Nuclear weapons are a problem for mankind
The fact that such a problem really exists, scientists realized after the end of World War II, after the nuclear bombings of Hiroshima and Nagasaki (1945 - the entry into the nuclear era), after the Caribbean crisis, after cold war many countries began to build up their nuclear capabilities. Since 1945, more than 2,000 nuclear weapons tests have been carried out on the ground, underground, in the air and in the waters of the World Ocean, which has led to both deaths of people and the deterioration of the ecological situation on the planet.
Fig 1. Nuclear bombing of Hiroshima and Nagasaki, consequences
After the end of the Second World War, more than 60 wars of a local nature were registered on the planet, in which 6.5 million people died. Many of these wars could escalate from local conflicts to global ones, with the use of nuclear weapons.
Currently, the countries (the main "nuclear" countries are the USA, Russia, England, France, India and Pakistan + 30 countries capable of creating and transporting nuclear weapons) have built up a nuclear potential capable of destroying all life on the planet 30-35 times.
Nuclear weapons, the global problem of mankind, belongs to the intersocial group of global problems.
Making the problem worse
Many scientists, politicians and public figures seriously thought about the problem of nuclear disarmament after:
- testing of a new nuclear bomb by the USSR on the island of Novaya Zemlya in 1961 (the blast wave "circled" the globe twice and caused panic in the ruling circles of the two superpowers - the USA and the USSR);
- catastrophe at the Chernobyl nuclear power plant in 1986 (it was then that it became clear that even if a “peaceful atom” can lead to such consequences, then even a single use of nuclear weapons can lead to nuclear winter and the death of all life on the planet).
Fig 2. Catastrophe at the Chernobyl nuclear power plant
M. Gorbachev, the leader of the USSR, in 1986 proposed Western countries completely destroy nuclear weapons, but no other head of state supported this project.
Solution to the problem
At the moment, work continues on solving the problem of the destruction of all nuclear weapons. It was started in the 60s when agreements were reached on a ban on nuclear tests in three environments. In the 1970s and 1980s, work was carried out to maintain the strategic parity of the nuclear powers and not build up nuclear weapons. And in the 90s, work began to reduce the level of nuclear parity and the destruction of nuclear weapons. Also in the 60s, the non-proliferation regime of nuclear weapons was turned on, which led to the fact that many countries on the planet are not able to create a "clean" nuclear bomb.
Currently, the countries continue to negotiate to reduce the level of nuclear potentials. This is necessary in order to exclude accidental nuclear war and the so-called HLG (mutually assured destruction).
What have we learned?
The threat of nuclear war and worldwide nuclear armament is indeed the most important global problem that needs to be addressed immediately. Scientists, politicians and public figures from all over the world are working on it, realizing that the use (and even testing) of nuclear weapons can lead to a global environmental catastrophe and the destruction of mankind.
Topic quiz
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Only twice in history have nuclear weapons been used, both of which were common signs-- nuclear weapons were used:
-- against the civilian population
-- with the application of the ultimate destruction of civilian objects (the cities of Hiroshima and Nagasaki)
- with the expectation that the mass death of the population will cause psychological damage to the enemy - i.e. the nuclear strike was carried out not so much on military targets as on the population.
Both times the US used nuclear weapons on 6 and 9 August.
On August 6, 1945, the US military launched a nuclear attack on Hiroshima.
Vicki writes that everything could have turned out differently if US Secretary of War Henry Stimson had not once spent his honeymoon in Kyoto - after all, this city, along with Yokohama, Kokura, Niigata and Nagasaki, was among the points proposed by the committee for selecting targets for applying the first nuclear strike in history.
Stimson rejected the plan to bomb Kyoto because cultural value the latter, and Hiroshima was chosen as the target - a city and military port with a population of about 245 thousand people at the time of the strike.
The United States struck not only and not so much with the aim of destroying military facilities, but with the aim of producing a psychological effect on global community and on the government of Japan - after all, such a weapon was used for the first time. The scale of the destruction was meant to demonstrate the US military power and push the Japanese authorities to unconditional surrender - which eventually happened. The events in Hiroshima carried away, according to various estimates, from 140 to 200 thousand people -- approximately 70-80 thousand people died at the same time, at the time of the bomb explosion, and from this number of the dead, several tens of thousands more directly near the fireball simply disappeared in a fraction of a second, disintegrating into molecules in hot air: the temperature under the plasma ball reached 4000 degrees Celsius. Those closest to the epicenter of the explosion died instantly, their bodies turned to coal.
On August 6, after receiving news of the successful atomic bombing of Hiroshima, US President Truman declared:
"We are now ready to destroy, even faster and more completely than before, all the ground-based production facilities of the Japanese in any city ... If they do not accept our conditions now, let them expect a rain of destruction from the air, the likes of which have not yet been on this planet."
Despite the fact that immediately after the bombing of Hiroshima the scale of destruction and the horror of the consequences became clear, on August 9 another nuclear strike was delivered.
The second atomic bombing (Kokura) was scheduled for August 11, but was postponed 2 days earlier.
On August 9, Nagasaki was bombed - the number of deaths by the end of 1945 as a result of this bombing, taking into account those who died from cancer and other long-term effects of the explosion, is estimated at 140 thousand people.
Japan estimates the total number of victims from the bombing and radiation sickness to be 286,818 in Hiroshima and 162,083 in Nagasaki.
The United States produced two new bombs, the Kid and the Fat Man, one using uranium and the other using plutonium, with different triggers for each. The main research and production centers were: Los Alamos (New Mexico), Hanford (Washington), Oak Ridge (Tennessee).
They were dropped - it is not known what the whole story would have turned out if the US leadership had at least a dozen nuclear bombs at hand by the beginning of August 1945.
Mass production will be established a little later, but that's a completely different story.
The US government expected that another atomic bomb would be ready for use in mid-August, and three more each in September and October.
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Some researchers argue that the main purpose atomic bombs The backing was to influence the USSR before its entry into the war with Japan in the Far East and to demonstrate the atomic power of the United States.
On August 6, 2015, the anniversary of the bombings, President Truman's grandson Clifton Truman Daniel stated that “grandfather believed until the end of his life that the decision to drop the bomb on Hiroshima and Nagasaki was the right one, and the United States would never ask for forgiveness for this”.
=================
Prior to 2015, most Americans supported the US government's nuclear bombing decisions.
In 2016, 43% of Americans supported the number of supporters of the bombings, which killed over 400,000 people.
Therefore, when calls are now being heard for the destruction of nuclear weapons (Japan regularly calls for this).
Hiroshima City Mayor Kazumi Matsui:
"Barack Obama, the first sitting US president to visit Hiroshima, said, 'Nuclear-weapon countries like my country must find the courage to move beyond the logic of fear and seek a world without nuclear weapons.' Obama's thoughts and feelings have reached Hiroshima. Now it is necessary, based on the feelings of Hiroshima, to take action with passion and solidarity to find ways to rid the world of this inhumane "absolute evil" in the form of nuclear weapons."
Hiroshima Mayor Kazumi Matsui gives heartfelt speeches every year about nuclear disarmament, along the way praising his eternal ally the United States and sometimes reproaching Russia for not moving so fast towards nuclear disarmament.
Emphasis is constantly placed on the Declaration of Peace, which calls for the adoption of a convention in order to completely get rid of nuclear weapons by 2020. 
I'm already writing a letter Kazumi Matsui, which can be repeated in these August days:
"Dear Kazumi Matsui, we sincerely sympathize with the Japanese people.
We are categorically against the war, but here's the catch - the words are already quite open that if it weren't for nuclear weapons, Russia would have long been taught how to organize cooperation with Ukraine, how to build its domestic (so far extremely imperfect) policy and would have been pressed not by sanctions, but probably by something else.
If a war that still guarantees mutual destruction were possible, then some countries would not stand on ceremony with such a laborious procedure as sanctions and so on, but would gobble up the whole thing.
You see, Kazumi, as long as Russia has nuclear weapons, they don’t really want to fight with it and they will try to cut it in a different way.
Think, Kazumi, how soon, after our last nuclear warhead has been sawn up here, will we be immediately confidently pointed to the path of great pacifism and democracy, which we cannot refuse?
The next day? A month later?
Oh, Kazumi, Kazumi, do you think your city would be bombed if you had a vigorous loaf in your bosom?
Would you now tell again about how the children of Hiroshima burned in a nuclear cloud?
How many countries do you think possessed nuclear weapons when the only act in the history of the destruction of civilians by nuclear weapons took place?
Oh, naive Kazumi, the US military is on the forums, bragging about how perfect the US troops are and how imperfect the Russian ones are (that they can even be crushed in 24 hours) and almost always mention that About the only trump card that Russia has is nukes.
Russia's life-saving trump card is that it has nuclear weapons - that's what the US military says among themselves.
Now, oh, good Kazumi Matsui, you can guess for yourself what we can advise you to do with the Declaration of Peace and the Convention on Complete Nuclear Disarmament by 2020, how it is more convenient for you to roll them up and how to shove them in one place.
After this procedure, you can ask the eternal ally of Japan, irrevocably repentant of the atrocities, to set fire to these documents stuck in one place and jump briskly, as the overzealous allies of your eternal ally, Kazumi, do.
You can even learn the words they yell at the same time.
These allies are very emotional, so they sometimes discuss how best to destroy their wrong fellow citizens, incl. with the help of nuclear weapons.
For some reason, this emotionality and craving for peace in no way prevents your eternal ally from openly sympathizing with the disorderly military operations in different parts light, which have already killed hundreds of thousands of civilians.
Means of using nuclear weapons. General device and
characteristics of nuclear weapons.
As discussed earlier, nuclear weapons include nuclear weapons, controls, and means of delivery to the target (carriers).
Nuclear munitions include warheads of missiles and torpedoes, aircraft and depth charges, artillery shells and mines, and land mines.
The power of charges and ammunition is usually characterized by the TNT equivalent - such a mass of TNT, the explosion energy of which is equal to the energy released during an air explosion of a nuclear charge. TNT equivalent is usually expressed in tons.
Modern ammunition can have explosive power q from several tens of tons to tens of millions of tons.
According to the power of the explosion, nuclear charges and ammunition are conditionally divided into 5 ranges (calibers):
Ultra Small ( q ‹ 1 thousand tons)
Small (1 ≤ q ‹ 10 thousand tons)
Medium (10 ≤ q ‹ 100 thousand tons)
Large (100 ≤ q ‹ 1000 thousand tons)
Extra Large ( q ≥ 1 million tons)
Nuclear charges and ammunition differ from each other not only in power, but also in the nature of the damaging effect. In particular, for thermonuclear ammunition, the most important characteristic is the thermonuclear coefficient - the ratio of the amount of energy released due to the fusion reaction to the total amount of explosion energy of a given power. With an increase in the thermonuclear coefficient, the yield of radioactive products per unit of power decreases and, thus, the “purity” of the explosion increases, and the scale of radioactive contamination decreases.
The main parts of a nuclear munition are: a nuclear charger (charge), a detonation unit with fuses and power sources, and a munition body. (Slide number 1.)
TO
the case is designed to accommodate a nuclear charge and an automation system, as well as to protect them from thermal damage, to give the ammunition a ballistic shape and to dock the ammunition with the carrier. The design of the case depends on the media type. So, for example, the main parts of ballistic missiles have conical or cylindrical bodies with a heat-shielding coating. The housings of combat charging compartments of torpedoes, warheads of cruise and anti-aircraft missiles are a thin-walled ampoule placed inside the carrier.
The automation system ensures the explosion of a nuclear charge at a given moment of time and excludes its accidental or premature operation. It includes:
Power supplies
Undermining sensor system
charge detonation system
emergency detonation system
The automation system ensures the explosion of a nuclear charge at a given moment of time and excludes its accidental or premature operation. It includes:
Power supplies
Safety and cocking system
Undermining sensor system
charge detonation system
emergency detonation system
The system of protection and cocking ensures safety during the operation of the ammunition, excludes its premature explosion during combat use and serves to cock the device of the automation system.
The detonation sensor system is designed to form an executive command to explode the charge when the ammunition reaches the target. It usually consists of an impact sensor system and a non-contact detonation sensor system. Impact (contact) sensors are triggered when the ammunition meets an obstacle. Non-contact detonation sensors are triggered at a given height (distance) from the target.
The charge detonation system ensures that the charge is triggered by a command from the detonation sensors. It consists of a unit for generating an electrical impulse to detonate electric detonators of a conventional explosive and a system for neutron initiation of a fission reaction. The neutron initiation system may be absent as part of the charge detonation system. In this case, the nuclear fission chain reaction is initiated by neutron sources located in the charge itself.
The emergency detonation system may not be available in some ammunition.
The main component of a nuclear weapon is a nuclear charger (nuclear charge). The composition of the nuclear charge is a nuclear explosive (NAE).
Atomic charges.
Due to the spontaneous fission of uranium or plutonium nuclei, the presence of stray neutrons in the atmosphere and other factors, no measures can be taken to prevent a chain reaction in a nuclear explosive having a supercritical mass (K pp > 1). Therefore, before the explosion, the total amount of nuclear explosives in one munition must be divided into separate parts, each of which has 5 less than critical (K rr ‹ 1). For an explosion, it is necessary to combine into a single whole such an amount of fissile material that will create a supercritical mass.
According to the principle of transferring a fissile material to a supercritical state, atomic charges are divided into charges of the cannon and implosive types.
2.1. Nuclear charges "gun type"
In "gun-type" charges, two or more parts of the fissile material are combined with each other into a supercritical mass as a result of the explosion of a conventional explosive due to the firing of one part of the charge into another, fixed at the opposite end of a strong metal cylinder resembling a gun barrel.
slide number 2 
The advantage of the cannon-type scheme is the ability to create charges of a relatively small diameter and high resistance to mechanical stress, which allows them to be used in artillery shells and mines.
The disadvantage of this scheme is the difficulty of providing high supercriticality, as a result of which its efficiency is low.
2.2. Nuclear charges of implosive type.
In implosive-type charges, the fissile material is transferred to a supercritical state by increasing its density as a result of all-round compression with the help of an explosion of a conventional explosive, since the critical mass is inversely proportional to the square of the substance density.
Slide number 3.
W 
and due to the inertia of the nuclear explosive and the strong shell, the nuclear charge is kept for some time in the supercritical state, as a result of which a certain number of nuclei of the fissile material has time to separate.
The advantage of implosive-type charges is the possibility of obtaining a high degree of supercriticality and, consequently, a high efficiency of the substance.
2.3. thermonuclear charges.
The main elements of a thermonuclear charge are thermonuclear fuel and an atomic charge - the initiator of the fusion reaction.
slide number 4
Scheme of the device of a thermonuclear munition of the "fission-fusion" type
1.- nuclear detonator (fission charge); 2.- charge for the fusion reaction (lithium deuteride); 3.- case
In the previous lesson, as the most significant reaction for obtaining nuclear energy, we considered the reaction of the compound D And T:
D + T → 2 He + n + 17.6 MeV (1)
Due to the fact that deuterium and tritium in the free state are gases, and tritium, in addition, is a radioactive and expensive isotope, lithium deuteride, a solid substance that is a compound of deuterium and an isotope of lithium, is usually used as the primary thermonuclear fuel. 3 Li.
When lithium is irradiated with 6 neutrons that occur during the explosion of an atomic charge (initiator of the fusion reaction), tritium is formed:
3 Li+ n → T + 2 He + 4.8 MeV (2)
The resulting tritium reacts with deuterium (1) and the main amount of energy is released.
The neutrons formed in reaction (1) again lead to the formation of tritium (2), i.e., to the maintenance of the fusion reaction.
Considering the fusion reaction in the previous lesson, we paid attention to the emission of high-energy neutrons. These neutrons are capable of causing fission of the nuclei of the uranium isotope. U-238. Isotope U-238 is the cheapest and most common - the natural mixture of uranium contains more than 99.98%. Therefore, to increase the energy of the explosion in thermonuclear charges, shells made of U-238. Nuclear fission U-238 will be the third phase of the explosion. Therefore, such ammunition, based on the principle of "fission - synthesis - fission", is called three-phase or combined.
2. Types of nuclear explosions and their characteristics.
Depending on the methods of application and the tasks solved by the use of nuclear weapons, the type and location of objects of destruction, and also depending on the properties of the environment surrounding the explosion zone, nuclear explosions are divided into air, high-altitude, ground (surface) and underground (underwater).
Air nuclear explosions are called explosions for which the environment surrounding the explosion zone is air. Air explosions include explosions in the atmosphere at altitudes:
3,5 3 √q ≤ H ≤ 10,000 m, where
q– explosion power, t
There are two main types of air bursts:
low bang
3,5 3 √q ≤ H ≤ 10 3 √q
high bang
H ≥ 10 3 √q
Ground nuclear explosions are called explosions on the surface of the earth (contact) and explosions in the air at altitudes H ‹ 3.5 3 √q.
High-altitude nuclear explosions are explosions for which the medium surrounding the explosion zone is rarefied air. Such explosions include explosions at altitudes of more than 10 km.
High-altitude nuclear explosions are divided into stratospheric
(10,000 m ‹ H ‹ 80,000 m) and space ( H › 80,000 m).
Surface nuclear explosions include contact explosions (on the surface of the water) and explosions in the air at heights H ‹ 3.5 3 √q.
Underwater and underground explosions include explosions for which the medium surrounding the reaction zone is water and, accordingly, soil.
In this lesson, we will consider air and ground nuclear explosions in more detail, since they are the most typical for use in combined arms combat and operations and have the greatest feasibility and variety of damaging factors.
2.1. air burst
Air nuclear explosions are called explosions for which the environment surrounding the explosion zone is air. In practice, air explosions include explosions in the atmosphere at altitudes: 3.5 3 q H 10,000 m, where q is the explosion power, i.e.
Low air bursts are intended to destroy personnel and destroy relatively strong objects of military equipment and ground structures. At the same time, radioactive contamination of the area will practically not affect the combat operations of the troops.
High air bursts are used to destroy low-strength ground objects and destroy personnel located in them or openly on the ground, while the area of destruction will be larger than with low air bursts. Also, high air explosions are used in cases where, according to the conditions of the situation, radioactive contamination of the area is unacceptable.
The physical processes accompanying air nuclear explosions are determined by the interaction of penetrating radiation, x-rays and gas flow with air.
Penetrating radiation and X-rays leaving the reaction zone cause excitation and ionization of the atoms and molecules of the surrounding air. Excited atoms and molecules emit light quanta upon transition to the ground state, as a result of which the so-called region of the initial air glow arises. This glow is luminescent in nature (glow of cold air). Its duration does not depend on the power of the explosion and is approximately ten microseconds, and the radius of the area of the initial airglow is approximately 300 m.
As a result of the interaction of gamma radiation with air atoms, high-energy electrons are formed, moving mainly in the direction of γ-quanta, and heavy positive ions, which practically remain in place. As a result of this separation of positive and negative charges, electrical and magnetic fields- an electromagnetic pulse (EMP), which manifests itself as a damaging factor in a nuclear explosion.
Simultaneously with the ionization of the air adjacent to the reaction zone, it is heated by X-rays. As a result, the formation of a luminous area begins, which is a plasma formation of air and vapors of ammunition construction materials (explosion products) heated to high temperatures.
During the existence of a luminous region, the temperature inside it changes from millions to several thousand kelvins.
The shape of the glowing area depends on the height of the explosion. With a high air burst, it is close to a sphere. The glowing area of a low air burst as a result of deformation by a shock wave reflected from the earth's surface has the form of a spherical segment.
The glow time and the diameter of the luminous area depend on the power of the explosion.
The light radiation of a nuclear explosion is essentially thermal in nature and manifests itself as a powerful damaging factor.
During atomic and conventional thermonuclear explosions in air, about 35% of their energy is transformed into light radiation.
As the luminous region cools, its glow stops, the vapors condense, it turns into an explosion cloud, which is a swirling mass of air mixed with hardened particles of explosion products, nitrogen oxides of air, water drops and ground dust particles.
The high temperature inside the area covered by the thermal wave in the thin outer layer is sharply reduced to the temperature of the surrounding cold air. Such a temperature difference causes the occurrence of large pressure gradients near the heat wave front. At the boundary of the region covered by the thermal wave, hydrodynamic perturbations accumulate, as a result of which a shock wave is generated inside the luminous region, which is a sharp compression of the medium propagating at supersonic speed.
For some time, the shock wave propagates inside the luminous region, since the rate of radiant heating, which determines the movement of the boundary of the luminous region, is greater than the velocity of the shock wave. As the luminous region cools, the heat wave propagation velocity decreases faster than the shock wave propagation velocity. At a temperature of 300 thousand K, they become equal, and at temperatures below 300 thousand K, the shock wave velocity becomes greater than the thermal wave velocity, and its front boundary (front) comes forward.
The air shock wave is one of the main damaging factors of a nuclear explosion.
Approximately 50% of the energy of an air explosion of an atomic and conventional thermonuclear charge is transformed into an air shock wave.
The explosion cloud, formed as a result of the increase and cooling of the luminous region, initially has a red or reddish-brown color, then as the number of water drops increases, it becomes white.
The maximum height of the cloud during nuclear explosions of medium power is 8-12 km. At this altitude, the horizontal size of the cloud reaches 5-9 km. A cloud of a super-large thermonuclear explosion can rise into the stratosphere to a height of 25 km, the horizontal size in this case can reach tens of kilometers.
The explosion cloud is radioactive. During the ascent and after stabilization of the ascent height, the cloud is transported to a greater distance under the action of air currents and dissipates. During the movement of the cloud, the radioactive products contained in it, mixed with dust and water drops, gradually fall out and cause radioactive contamination of the atmosphere and terrain.
As a result of the impact on the soil of light radiation, the shock wave and the air flows following it, as well as the air flows that appear as a result of the rise of the luminous area first, and then the explosion cloud, a dusty surface layer of the atmosphere is formed. The surface dusty layer exists for tens of minutes.
Its maximum diameter depends on the power and height of the explosion, the properties of the soil, the nature of the terrain and vegetation in the area of the epicenter of the explosion.
Simultaneously with the surface dusty layer of the atmosphere, due to the suction effect that occurs in the region of the epicenter of the explosion as a result of the rise of the luminous area first, and then the explosion cloud, as well as the convective heat exchange of air with the earth's surface unevenly heated by light radiation, a dust column is formed - an upward flow of air with soil particles .
The dust column has a dark brown color - the color of the soil in the area of the epicenter of the explosion.
With an explosion at a height H ≤ 3 q m dust column catches up with the cloud and connects with it. In this case, soil particles are introduced into the explosion cloud, it becomes brown.
If H 3 q, the dust column does not connect with the explosion cloud and it contains practically no ground particles.
Dust formations (surface dusty layer of the atmosphere and dust column) can have an aerodynamic, thermal and erosive (abrasive) effect on aircraft, hinder the operation of radar stations, and disable filter-ventilation systems. Therefore, dust formations are considered as a damaging factor in a nuclear explosion.
By the end of its development, the external picture of an air nuclear explosion takes on a mushroom-like appearance.
Thus, the damaging factors of an air nuclear explosion are: air shock wave, light radiation, penetrating radiation, electromagnetic pulse, explosion cloud, ionization and radioactive contamination of the atmosphere. In addition, during an air explosion over land, dust formations, weak radioactive contamination of the area, as well as weak mechanical vibrations of the ground (seismic explosive waves) resulting from the impact of an air shock wave on it can occur.
2.2. ground explosion
Ground-based nuclear explosions include explosions on the surface of the earth (contact) and explosions in the air at altitudes H< 3,5 3 q, at which the luminous area touches the surface of the earth.
Ground explosions are used both to destroy various objects in the area of the explosion, and to destroy personnel operating in zones of radioactive contamination.
In the air environment during ground-based nuclear explosions, the same processes occur as during air ones. The difference between ground nuclear explosions and air explosions lies mainly in the fact that during ground explosions, the luminous area at the time of occurrence has the form of a truncated sphere (contact - hemisphere), the radius of which is greater than the radius of the sphere of the luminous area of air explosions of the same power, the environment inside the luminous area in its surface part it contains a large number of soil particles, the temperature inside the luminous region is somewhat lower than during air explosions, the dust column connects with the explosion cloud at the stage of its formation, the explosion cloud is much more polluted with soil particles.
The formation of a funnel during ground explosions is due to evaporation, melting, ejection and indentation of soil into the massif: the appearance of a heap of soil is due to the ejection and extrusion of soil from the funnel.
Seismic explosive waves during ground explosions arise as a result of the direct transfer of explosion energy to the ground and the impact of an air shock wave on the ground.
The formation of a funnel and the intensity of seismic waves depend significantly on the height of the explosion. The funnel is formed only during explosions at heights H< 0,5 3 q. Intense seismic waves occur during explosions at heights less than H< 0,3 3 q.
By the end of their development, ground-based nuclear explosions, like air ones, take on a mushroom-like appearance. The difference between the appearance of ground explosions and air explosions is that during ground explosions, a more powerful surface dusty layer of the atmosphere and a dust column are observed, as well as a darker color of the explosion cloud, which is caused by contamination with a large number of soil particles.
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The initial stage in the development of nuclear energy (40–50s of the 20th century) both in the USA and in the USSR is associated with the technical capacities and scientific potential of the military-industrial complex. During that period, the first research nuclear reactors for military purposes were developed and launched: in 1942 - in Chicago, USA (uranium-graphite reactor CP-1, designed by a group of physicists at the University of Chicago under the leadership of E. Fermi); in 1946 - in Moscow, USSR (the F-1 uranium-graphite reactor, created by a group of physicists and engineers led by I.V. Kurchatov).
The United States of America, as part of the so-called Manhattan Project, created the first atomic bombs. It should be noted that the world's first application for an invention for the manufacture of an atomic bomb was dated October 17, 1940. It belonged to employees of the Kharkov Institute of Physics and Technology of the Academy of Sciences of the Ukrainian SSR V.O. Maslov and V.S. Spinel "On the use of uranium as an explosive and poisonous substance".
The first atomic bomb, called the Device, was detonated as part of a test in New Mexico on July 16, 1945. In the cities of Hiroshima and Nagasaki (Japan) on August 6 and 9, 1945, the second and third atomic bombs were detonated, which were named respectively "Kid" (Fig. 3.9) and "Fat Man" (Fig. 3.10). Military experts believed that uranium-235 bombs would have low effectiveness, since only 1.38% of the material was fissioned in them. To date, this is the only example of the combat use of atomic weapons.
At the time of the attack, the population of Hiroshima was approximately 255,000. From the moment the bomb was dropped to the explosion, 45 seconds passed (Fig. 3.11). It exploded 600 meters above the earth's surface with a blinding flash in the form of a giant fireball with a temperature of more than 4000 ° C. Radiation spread instantly in all directions with a blast wave of super-compressed air, bringing death and destruction. During the explosion of the “Kid”, approximately 70-80 thousand people died on the spot. The radius of the zone of complete destruction was approximately 1.6 kilometers, and fires broke out over an area of 11.4 km 2. Over 90% of Hiroshima's buildings were either damaged or completely destroyed (Fig. 3.12, 3.13). From an unknown disease, later called "radiation", tens of thousands of Hiroshima residents and residents of the surrounding area began to die. Due to the radiation "epidemic", the death toll in the coming weeks rose to 110,000, and after a lapse of months - up to 140,000.
The plutonium bomb "Fat Man" exploded near the surface of the earth over one of the churches in the central part of the city of Nagasaki. As a result of the explosion, the city and its inhabitants were almost completely destroyed (Fig. 3.14, 3.15).
The total death toll in Nagasaki was 75 thousand people. In both cities, the vast majority of victims were civilians.
This was the period of the arms race, which was marked by the rivalry between the two main world supersystems that formed after the end of the Second World War - the Warsaw Pact countries led by the USSR and the countries of the NATO bloc led by the United States. Later, China, England, and France joined in the testing of nuclear weapons.
As a result of these tests, radioactive substances of technogenic origin, which were previously not characteristic of our planet, entered the atmosphere for the first time. An artificial radiation background has arisen - global, all over the globe, pollution environment radionuclides from nuclear explosions. Particularly harmful were explosions in the atmosphere, when radioactive decay products infected large areas inhabited by people. During nuclear explosions in the atmosphere, a certain part of the radionuclides (up to 50% in ground explosions) falls out near the test area. However, a significant proportion of radioactive substances is retained in the air and, under the influence of the wind, moves over long distances, remaining approximately at the same latitude. Being in the air for about a month, radioactive substances during this movement gradually fall to the ground. Most of the radionuclides are released into the stratosphere (to a height of 10–15 km), and then the radionuclides fall out over the entire surface of the Earth. Radioactive fallout contains a large number of different radionuclides, but of these, 95 Cr, tritium, 17 Cs, 90 Sr and 14 C play the largest role, the half-lives of which are respectively 64 days, 12.4 years, 30 years (cesium and strontium) and 5730 years.
Especially intensive tests of nuclear weapons were carried out in the periods 1954-1958 and 1961-1962.
According to official data, at the existing five nuclear test sites - Nevada (USA, UK), Novaya Zemlya (USSR, now Russia); Semipalatinsk (USSR, now Kazakhstan), Mururoa Atoll (France), Lop Nor (China) - most of the 2059 experimental nuclear explosions were carried out different types, including 501 tests conducted directly in the atmosphere. For the entire period of testing, the activities of the main radionuclides that came to the earth's surface from global fallout amounted to: 949PBq 137 Cs, 578PBq 90 Sr and 5550PBq 131 J. However, many experts believe that the given data on radioactive releases into the environment are underestimated, and therefore real indicators should be increased by 20-30%.
The concept of "radioactive contamination" did not yet exist in those years, and therefore this issue was not even raised at that time. People continued to live and rebuild the destroyed buildings in the same place where they were before. Even the extremely high mortality of the population in subsequent years, as well as diseases and genetic abnormalities in children born after the bombings, were not initially associated with exposure to radiation. The evacuation of the population from the contaminated areas was not carried out, since no one knew about the very presence of radioactive contamination. The degree of this pollution is now rather difficult to assess due to lack of information. However, given that the dropped bombs were the second and third instances of atomic weapons, they were technically imperfect, “dirty” in the language of specialists, that is, they left strong radioactive contamination of the area after the explosion.
From a military point of view, the atomic bombing was a senseless cruelty, since the outcome of the Second World War was already a foregone conclusion by this time and the actions of the US government were a show of force.
This led to a significant acceleration in the pace of the Soviet nuclear program. On October 25, 1946, an experimental graphite reactor was launched in Moscow. It consisted of 450 tons of graphite blocks, inside of which blocks of natural uranium were placed. The experimental work carried out at this reactor made it possible to evaluate the fundamental features and prospects of the new nuclear technology, and also provided the initial data for the design of more complex reactor designs. In particular, in June 1948, the first industrial reactor began to operate in the USSR, which was used mainly for military research purposes.
The test of the first Soviet nuclear device, called RDS-1, was carried out on August 29, 1949 at the Semipalatinsk test site. The power of the explosion produced corresponded to the calculated power of the device and amounted to 22 kW.
In the course of tests in 1951, a more advanced nuclear explosive device was detonated, and the delivery of a nuclear weapon using a bomber was also carried out for the first time. To practice the actions of troops in the conditions of the use of nuclear weapons, in September 1954, military exercises were held at the Taromskoye (Novaya Zemlya) training ground, during which a nuclear warhead was detonated.
In parallel with the improvement of atomic bombs based on the uncontrolled fission chain reaction of 235 U and 239 Pu, work was actively carried out in the USA and the USSR on the creation of thermonuclear explosive devices based on the fusion reaction of heavy hydrogen isotopes (deuterium and tritium). The first Soviet thermonuclear device was the RDS-6 charge, which exploded on August 12, 1953. After this test, work began on the creation of a delivered ammunition on its basis, as well as work on the creation of two-stage thermonuclear devices that made it possible to create charges of greater power. The delivered version of the RDS-6 charge and a two-stage thermonuclear device, designated RDS-37, were tested in October-November 1955. The power of the explosion produced on November 22, 1955 during the test of the RDS-37 thermonuclear device was 1.6 MW.
By the end of the 50s of the twentieth century. in the USSR and the USA, the formation of the infrastructure necessary for the mass production of fissile materials and nuclear warheads was basically completed.
Naturally, almost no one seriously thought about the problems of preserving and protecting the natural environment at that time. Tests of nuclear weapons have led to severe environmental consequences on a global scale: for the first time in the history of the planet Earth, as a result of radioactive fallout, the radiation background has noticeably increased on almost its entire surface.
During this period, along with military nuclear programs, scientific and technical programs for the use of nuclear energy for energy purposes and, first of all, for solving the problems of generating electrical energy, became more active.
In 1951, in the USA, in the state of Idaho, at the experimental reactor EVR-1, electric energy was first obtained due to the heat from the fission reaction of uranium nuclei.
The Soviet Union was the first in world history to open the era of the industrial use of atomic energy for peaceful purposes. This happened on June 27, 1954, when the world's first Obninsk nuclear power plant was put into operation.
Explosive action, based on the use of intranuclear energy released during chain reactions of fission of heavy nuclei of some isotopes of uranium and plutonium or during thermonuclear reactions of fusion of hydrogen isotopes (deuterium and tritium) into heavier ones, for example, helium isogon nuclei. In thermonuclear reactions, energy is released 5 times more than in fission reactions (with the same mass of nuclei).
Nuclear weapons include various nuclear weapons, means of delivering them to the target (carriers) and controls.
Depending on the method of obtaining nuclear energy, ammunition is divided into nuclear (on fission reactions), thermonuclear (on fusion reactions), combined (in which energy is obtained according to the “fission-fusion-fission” scheme). The power of nuclear weapons is measured in TNT equivalent, t. a mass of explosive TNT, the explosion of which releases such an amount of energy as the explosion of a given nuclear bosiripas. TNT equivalent is measured in tons, kilotons (kt), megatons (Mt).
Ammunition with a capacity of up to 100 kt is designed on fission reactions, from 100 to 1000 kt (1 Mt) on fusion reactions. Combined munitions can be over 1 Mt. By power, nuclear weapons are divided into ultra-small (up to 1 kg), small (1-10 kt), medium (10-100 kt) and extra-large (more than 1 Mt).
Depending on the purpose of using nuclear weapons, nuclear explosions can be high-altitude (above 10 km), air (not more than 10 km), ground (surface), underground (underwater).
Damaging factors of a nuclear explosion
The main damaging factors of a nuclear explosion are: a shock wave, light radiation from a nuclear explosion, penetrating radiation, radioactive contamination of the area and an electromagnetic pulse.
shock wave
Shockwave (SW)- a region of sharply compressed air, spreading in all directions from the center of the explosion at supersonic speed.
Hot vapors and gases, trying to expand, produce a sharp blow to the surrounding layers of air, compress them to high pressures and densities and heat up to high temperature(several tens of thousands of degrees). This layer of compressed air represents the shock wave. The front boundary of the compressed air layer is called the front of the shock wave. The SW front is followed by an area of rarefaction, where the pressure is below atmospheric. Near the center of the explosion, the velocity of SW propagation is several times higher than the speed of sound. As the distance from the explosion increases, the wave propagation speed decreases rapidly. At large distances, its speed approaches the speed of sound in air.
The shock wave of an ammunition of medium power passes: the first kilometer in 1.4 s; the second - in 4 s; the fifth - in 12 s.
The damaging effect of hydrocarbons on people, equipment, buildings and structures is characterized by: velocity pressure; overpressure in the shock front and the time of its impact on the object (compression phase).
The impact of HC on people can be direct and indirect. With direct impact, the cause of injury is an instant increase in air pressure, which is perceived as a sharp blow leading to fractures, damage internal organs rupture of blood vessels. With indirect impact, people are amazed by flying debris of buildings and structures, stones, trees, broken glass and other objects. Indirect impact reaches 80% of all lesions.
With an overpressure of 20-40 kPa (0.2-0.4 kgf / cm 2), unprotected people can get light injuries (light bruises and concussions). The impact of SW with excess pressure of 40-60 kPa leads to lesions of moderate severity: loss of consciousness, damage to the hearing organs, severe dislocations of the limbs, damage to internal organs. Extremely severe lesions, often fatal, are observed at excess pressure over 100 kPa.
The degree of shock wave damage to various objects depends on the power and type of explosion, the mechanical strength (stability of the object), as well as on the distance at which the explosion occurred, the terrain and the position of objects on the ground.
To protect against the impact of hydrocarbons, one should use: trenches, cracks and trenches, which reduce its effect by 1.5-2 times; dugouts - 2-3 times; shelters - 3-5 times; basements of houses (buildings); terrain (forest, ravines, hollows, etc.).
light emission
light emission is a stream of radiant energy, including ultraviolet, visible and infrared rays.
Its source is a luminous area formed by the hot products of the explosion and hot air. Light radiation propagates almost instantly and lasts, depending on the power of a nuclear explosion, up to 20 s. However, its strength is such that, despite its short duration, it can cause skin (skin) burns, damage (permanent or temporary) to the organs of vision of people, and ignition of combustible materials of objects. At the moment of formation of a luminous region, the temperature on its surface reaches tens of thousands of degrees. The main damaging factor of light radiation is a light pulse.
Light pulse - the amount of energy in calories falling per unit area of the surface perpendicular to the direction of radiation, for the entire duration of the glow.
Attenuation of light radiation is possible due to its screening by atmospheric clouds, uneven terrain, vegetation and local objects, snowfall or smoke. Thus, a thick layer attenuates the light pulse by A-9 times, a rare layer - by 2-4 times, and smoke (aerosol) screens - by 10 times.
To protect the population from light radiation, it is necessary to use protective structures, basements of houses and buildings, and the protective properties of the terrain. Any obstruction capable of creating a shadow protects against the direct action of light radiation and eliminates burns.
penetrating radiation
penetrating radiation- notes of gamma rays and neutrons emitted from the zone of a nuclear explosion. The time of its action is 10-15 s, the range is 2-3 km from the center of the explosion.
In conventional nuclear explosions, neutrons make up approximately 30%, in the explosion of neutron ammunition - 70-80% of the y-radiation.
The damaging effect of penetrating radiation is based on the ionization of cells (molecules) of a living organism, leading to death. Neutrons, in addition, interact with the nuclei of atoms of certain materials and can cause induced activity in metals and technology.
The main parameter characterizing the penetrating radiation is: for y-radiation - the dose and dose rate of radiation, and for neutrons - the flux and flux density.
Permissible exposure doses for the population in wartime: single - within 4 days 50 R; multiple - within 10-30 days 100 R; during the quarter - 200 R; during the year - 300 R.
As a result of the passage of radiation through the materials of the environment, the intensity of the radiation decreases. The weakening effect is usually characterized by a layer of half attenuation, i.e. with. such a thickness of the material, passing through which the radiation is reduced by 2 times. For example, the intensity of the y-rays is reduced by 2 times: steel 2.8 cm thick, concrete - 10 cm, soil - 14 cm, wood - 30 cm.
Protective structures are used as protection against penetrating radiation, which weaken its impact from 200 to 5000 times. A pound layer of 1.5 m protects almost completely from penetrating radiation.
Radioactive contamination (contamination)
Radioactive contamination of the air, terrain, water area and objects located on them occurs as a result of the fallout of radioactive substances (RS) from the cloud of a nuclear explosion.
At a temperature of approximately 1700 ° C, the glow of the luminous region of a nuclear explosion stops and it turns into a dark cloud, to which a dust column rises (therefore, the cloud has a mushroom shape). This cloud moves in the direction of the wind, and RVs fall out of it.
The sources of RS in the cloud are the fission products of nuclear fuel (uranium, plutonium), the unreacted part of the nuclear fuel and radioactive isotopes formed as a result of the action of neutrons on the ground (induced activity). These RVs, being on contaminated objects, decay, emitting ionizing radiation, which in fact are the damaging factor.
The parameters of radioactive contamination are the radiation dose (according to the impact on people) and the radiation dose rate - the level of radiation (according to the degree of contamination of the area and various objects). These parameters are a quantitative characteristic of damaging factors: radioactive contamination during an accident with the release of radioactive substances, as well as radioactive contamination and penetrating radiation during a nuclear explosion.
On the terrain that has undergone radioactive contamination during a nuclear explosion, two sections are formed: the area of the explosion and the trace of the cloud.
According to the degree of danger, the contaminated area along the trail of the explosion cloud is usually divided into four zones (Fig. 1):
Zone A- zone of moderate infection. It is characterized by a dose of radiation until the complete decay of radioactive substances at the outer boundary of the zone 40 rad and at the inner - 400 rad. The area of zone A is 70-80% of the area of the entire footprint.
Zone B- zone of severe infection. The radiation doses at the boundaries are 400 rad and 1200 rad, respectively. The area of zone B is approximately 10% of the area of the radioactive trace.
Zone B- zone dangerous infection. It is characterized by radiation doses at the borders of 1200 rad and 4000 rad.
Zone G- zone of extremely dangerous infection. Doses at the borders of 4000 rad and 7000 rad.
Rice. 1. Scheme of radioactive contamination of the area in the area of a nuclear explosion and in the wake of the movement of the cloud
Radiation levels at the outer boundaries of these zones 1 hour after the explosion are 8, 80, 240, 800 rad/h, respectively.
Most of the radioactive fallout, causing radioactive contamination of the area, falls out of the cloud 10-20 hours after a nuclear explosion.
electromagnetic pulse
Electromagnetic pulse (EMP) is a set of electric and magnetic fields resulting from the ionization of the atoms of the medium under the influence of gamma radiation. Its duration is a few milliseconds.
The main parameters of EMR are currents and voltages induced in wires and cable lines, which can lead to damage and disable electronic equipment, and sometimes to damage to people working with the equipment.
During ground and air explosions, the damaging effect of an electromagnetic pulse is observed at a distance of several kilometers from the center of a nuclear explosion.
The most effective protection against an electromagnetic pulse is the shielding of power supply and control lines, as well as radio and electrical equipment.
The situation that develops during the use of nuclear weapons in the centers of destruction.
The focus of nuclear destruction is the territory within which, as a result of the use of nuclear weapons, mass destruction and death of people, farm animals and plants, destruction and damage to buildings and structures, utility and energy and technological networks and lines, transport communications and other objects occurred.
Zones of the focus of a nuclear explosion
To determine the nature of possible destruction, the volume and conditions for conducting rescue and other urgent work, the nuclear lesion site is conditionally divided into four zones: complete, strong, medium and weak destruction.
Zone of complete destruction has an overpressure at the front of the shock wave of 50 kPa at the border and is characterized by massive irretrievable losses among the unprotected population (up to 100%), complete destruction of buildings and structures, destruction and damage to public energy and technological networks and lines, as well as parts of shelters civil defense, the formation of continuous blockages in settlements. The forest is completely destroyed.
Zone of severe damage with overpressure at the front of the shock wave from 30 to 50 kPa is characterized by: massive irretrievable losses (up to 90%) among the unprotected population, complete and severe destruction of buildings and structures, damage to public utilities and technological networks and lines, the formation of local and continuous blockages in settlements and forests, the preservation of shelters and the majority of anti-radiation shelters of the basement type.
Medium damage zone with an excess pressure of 20 to 30 kPa is characterized by irretrievable losses among the population (up to 20%), medium and severe destruction of buildings and structures, the formation of local and focal blockages, continuous fires, the preservation of utility networks, shelters and most of the anti-radiation shelters.
Zone of weak damage with excess pressure from 10 to 20 kPa is characterized by weak and medium destruction of buildings and structures.
The focus of the lesion but the number of dead and injured can be commensurate with or exceed the lesion in an earthquake. So, during the bombing (bomb power up to 20 kt) of the city of Hiroshima on August 6, 1945, most of it (60%) was destroyed, and the death toll amounted to 140,000 people.
The personnel of economic facilities and the population entering the zones of radioactive contamination are exposed to ionizing radiation, which causes radiation sickness. The severity of the disease depends on the dose of radiation (irradiation) received. The dependence of the degree of radiation sickness on the magnitude of the radiation dose is given in Table. 2.
Table 2. Dependence of the degree of radiation sickness on the magnitude of the radiation dose
Under the conditions of hostilities with the use of nuclear weapons, vast territories may turn out to be in the zones of radioactive contamination, and exposure of people may take on a mass character. In order to exclude overexposure of the personnel of objects and the population in such conditions and to increase the stability of the functioning of objects of the national economy in conditions of radioactive contamination in wartime, they establish allowable doses irradiation. They make up:
- with a single irradiation (up to 4 days) - 50 rad;
- repeated irradiation: a) up to 30 days - 100 rad; b) 90 days - 200 rad;
- systematic exposure (during the year) 300 rad.
Caused by the use of nuclear weapons, the most complex. To eliminate them, disproportionately greater forces and means are needed than in the elimination of emergency situations in peacetime.