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Atomic bomb from plutonium. The first atomic bombs

In many of our readers, the hydrogen bomb is associated with atomic, only much more powerful. In fact, this is a fundamentally new weapon that required for its creation is incommensurable in intellectual efforts and working on fundamentally other physical principles.

The only thing that the atomic and hydrogen bomb relates is that both are released with colossal energy hidden in the atomic core. You can do this in two ways: split heavy nuclei, for example, uranium or plutonium, to lighter (fission reaction) or make the loss of the lightest isotopes of hydrogen (synthesis reaction). As a result of both reactions, the mass of the resulting material is always less than the mass of the source atoms. But the mass cannot disappear without a trace - it turns into energy according to the famous Einstein formula E \u003d MC 2.

To create an atomic bomb necessary and sufficient condition is to obtain a dividing material in sufficient quantity. The work is quite time-consuming, but low-altextual, lying closer to the mining industry than to high science. The main resources in creating such weapons go to the construction of giant uranium mines and processing plants. Evidence of the simplicity of the device is the fact that there was no month and the first Soviet nuclear explosion between the receipt of the required first bomb of Plutonium and the first Soviet nuclear explosion.

Recall briefly the principle of operation of such a bomb, known from the course of school physics. It is based on the property of uranium and some transuranone elements, for example, plutonium, during decay to highlight more than one neutron. These elements can disintegrate both spontaneously and under the influence of other neutrons.

The released neutron can leave the radioactive material, and may face another atom, causing another fission reaction. When a certain concentration of the substance (critical mass) is exceeded, the number of newborn neutrons, causing further division of the atomic nucleus, begins to exceed the number of disintegrating nuclei. The amount of disintegrating atoms begins to grow avalanche-like, giving birth to new neutrons, that is, a chain reaction occurs. For uranium-235, the critical mass is about 50 kg, for plutonium-239 - 5.6 kg. That is, a plutonium bulb mass a little less than 5.6 kg is a simply warm piece of metal, and a slightly more than a few nanoseconds exist.

Actually, the Bomb scheme is simple: we take two hemispheres of uranium or plutonium, each little less critical Mass, we have them at a distance of 45 cm, we look explosive and blast. Uranium or plutonium socks into a piece of supercritical mass, and a nuclear reaction begins. Everything. There is another way to run nuclear reaction - Fit powerful explosion Plutonium slice: the distance between atoms will decrease, and the reaction will begin with a smaller critical mass. In this principle, all modern atomic detonators work.

The problems of the atomic bomb start from the moment when we want to increase the power of the explosion. A simple increase in the dividing material is not to do - as soon as its mass reaches critical, he detonates. Different ingenious schemes were invented, for example, to make a bomb from two parts, and from the set, why the bomb began to resemble the rental orange, and then collect it in one piece in one blast, but still with the power of more than 100 kiloton problems became irresistible.

But the fuel for thermonuclear synthesis of the critical mass does not have. Here is the sun filled with thermonuclear fuel, hanging over his head, inside it already a billion years has a thermonuclear reaction, - and nothing, does not explode. In addition, when the synthesis reaction, for example, the deuterium and tritium (heavy and superheavy isotope of hydrogen), the energy is 4.2 times larger than when combustion of the same mass of uranium-235.

The manufacture of an atomic bomb was more experimental than the theoretical process. Creating hydrogen bombs It demanded the emergence of completely new physical disciplines: high-temperature plasma physics and ultrahigh pressures. Before starting to design a bomb, it was necessary to thoroughly understand the nature of the phenomena occurring only in the kernel of the stars. No experiments here could not help - the tools of researchers were only theoretical physics And the highest mathematics. Not by chance a gigantic role in the development of thermo nuclear weapons Belongs to Mathematics: Ulama, Tikhonov, Samara, etc.

Classic super

By the end of 1945, Edward Teller offered the first design of the hydrogen bomb, the named "classic super". To create a monstrous pressure and temperature needed to start the synthesis reaction, an ordinary atomic bomb was assumed. The "classic super" himself was a long cylinder filled with deuterium. An intermediate "ostable" chamber with the deuterium industry mixture was also envisaged - the reaction of the synthesis of deuterium and tritium begins at a lower pressure. By analogy with Kostroma, Deuterium was to play the role of firewood, a mixture of deuterium with a tritium - a glass of gasoline, and the atomic bomb - matches. Such a scheme was called "Pipe" - a peculiar cigar with an atomic lighter from one end. According to the same scheme, the hydrogen bomb and Soviet physics began to develop.

However, Mathematics Stanislav Ulam on an ordinary logarithmic lineer proved to the teller that the emergence of the reaction of the synthesis of pure deuterium in the "Super" is hardly possible, and for the mixture it would be necessary for the amount of tritium that it would be necessary to practically freeze the production of armory plutonium in the United States.

Puff with sugar

In mid-1946, Teller proposed the next diagram of the hydrogen bomb - "alarm clock". It consisted of alternating spherical layers Uranus, deuterium and tritium. With a nuclear explosion of the central charge of plutonium, the required pressure and temperature was created to begin thermonuclear reaction in other layers of the bomb. However, for the "alarm clock" required atomic initiator of high power, and the United States (as, however, and the USSR) experienced problems with the development of weapons uranium and plutonium.

In the fall of 1948, Andrei Sakharov came to a similar scheme. In the Soviet Union, the design was called "Puff". For the USSR, who did not have time to work in sufficiently to work out the Armory Uranus-235 and Plutonium-239, the Sakharov Puff was a panacea. And that's why.

In a conventional atomic bomb, natural uranium-238 is not only useless (neutron energy during decay lacks for the initiation of division), but also harmful, since greedily absorbs secondary neutrons, slowing down the chain reaction. Therefore, the weapon uranium is 90% composed of uranium-235 isotope. However, neutrons appearing as a result of thermonuclear synthesis, 10 times more energy than the neutrons of division, and the natural uranium-238 irradiated with such neutrons begins to be excellently sharing. The new bomb allowed URAN-238 as explosives, which was previously considered as waste production.

The highlight of the Sakharov "Puff" was also used instead of the prominent tritium of the white light crystalline substance - a detertainment of lithium lithium 6 LID.

As mentioned above, the mixture of deuterium and tritium is much easier than pure deuterium. However, this advantages of tritium end, and some disadvantages remain: in the normal state of tritium - gas, which is why difficulties with storage arise; Trithium radioactive and, decaying, turns into stable helium-3, actively devouring so necessary rapid neutrons, which limits the shelf life of the bomb by a few months.

A non-radiative lithium dealer at irradiation of its slow neutrons of division - the consequences of the atomic explosion - turns into tritium. Thus, the radiation of the primary atomic explosion develops the amount of tritium sufficient for further the further thermonuclear reaction, and the deuterium in the lithium deuteride is initially present.

It is such a bomb, RDS-6C, and was successfully tested on August 12, 1953 at the Tower of Semipalatinsky Polygon. The power of the explosion was 400 kilotons, and there were still no disputes, whether it was a real termanuclear explosion or heavy-duty atomic. After all, the response of thermonuclear synthesis in the Saharov puff had no more than 20% of the total charge power. The main contribution to the explosion introduced the decay reaction irradiated with rapid neutrons of uranium-238, thanks to which RDS-6C and opened the era of the so-called "dirty" bombs.

The fact is that the main radioactive contamination is given to the decay products (in particular, strontium-90 and cesium-137). Essentially, the Sakharov "Puff" was a giant atomic bomb, only a slightly enhanced by thermonuclear reaction. It is not by chance that only one explosion "puffs" gave 82% strontium-90 and 75% Cesium-137, which fell into the atmosphere in the entire history of the existence of the Semipalatinsky landfill.

American bomb

Nevertheless, the Americans blew the first hydrogen borrow. November 1, 1952 by ElGelab at Volle Pacific Ocean The thermalide device "Mike" with a capacity of 10 megaton was successfully tested. Name a bomb 74-ton American device with great difficulty. "Mike" was a cumbersome device with a two-storey house, filled with liquid deuterium at a temperature close to the absolute zero (Sakharov "Puff" was a completely transportable product). However, the highlight of the "Mike" was not the dimensions, but a brilliant principle of compression of thermonuclear explosives.

Recall that the basic idea of \u200b\u200ba hydrogen bomb is to create conditions for synthesis (ultra-high pressure and temperature) by means of a nuclear explosion. In the layer scheme, the nuclear charge is located in the center, and therefore it does not compresses the deuterium so much as it disrupts it - an increase in the number of thermonuclear explosives does not lead to an increase in power - it simply does not have time to detonate. It is precisely that the limit capacity of this scheme is limited - the most powerful "Ployer" Orange Herald, blown up by the British on May 31, 1957, gave only 720 kilotons.

I would ideally, if it would be forced to explode the atomic washed inside, squeezing thermonuclear explosive. But how to do that? Edward Teller pushed the brilliant idea: to compress thermonuclear fuel non-mechanical energy and neutron flow, but the radiation of the primary atomic sunbathing.

In the new teller design, the initiating nuclear unit was separated with the thermonuclear unit. X-ray radiation when the atomic charge is triggered by the shock wave and spread along the walls of the cylindrical body, evaporating and turning into a plasma polyethylene inner lining of the bomb case. Plasma, in turn, re-erected a softer X-ray radiation, which was absorbed by the external layers of the inner cylinder from Urana-238 - "Pusher". The layers began to evaporate explosively (this phenomenon is called ablation). A hot uranium plasma can be compared with the streams of the heavy duty rocket engine, the thrust of which is directed inside the cylinder with the deuterium. The uranium cylinder collapsed, the pressure and temperature of the deuterium reached the critical level. This pressure crimped the central plutonium tube to the critical mass, and it was detonated. The explosion of plutonium smelled to deuterium from the inside, additionally squeezing and heating thermonuclear explosive, which was detonated. The intense neutron flux splits uranium-238 kernel in the "Puster", causing a secondary decay reaction. All this managed to occur until the moment when the explosive wave from the primary nuclear explosion reached the thermonuclear block. The calculation of all these events taking place for billion dollars of a second, and demanded the stress of the mind of the strongest mathematicians of the planet. The creators of the "Mike" were not horror from a 10 megaton explosion, but an indescribable delight - they managed not only to understand the processes that real world They go only in the nuclei of the stars, but also experimentally test their theories, setting up their small star on Earth.

Bravo

Walking around the Russians on the beauty of the design, the Americans could not make their device compact: they used liquid supercooled deuterium instead of a powdered lithium deuteride at Sakharov. In Los Alamos, the Sakharov "Ploch" reacted with the share of envy: "Instead of a huge cow with a bundle of raw milk, the Russians use the milk package." However, the secrets from each other did not manage to hide the secrets. On March 1, 1954, the Bikini atoll was tested by the American Bervo's 15-megaton bomb on Auditide Lithium, and on November 22, 1955, the first Soviet two-stage Bomb of RDS-37 RDS-37 with a capacity of 1.7 megaton rushed over the Semipalatinsky polygon. Since then, the design of the thermonuclear bomb has undergone minor changes (for example, a uranium screen has appeared between the initiating bomb and the main charge) and became canonical. And in the world there are no more so large-scale mysteries of nature, to solve which could be so spectacular experiment. Is that the birth of a supernovae.

A bit of theory

In the thermonuclear bomb there are 4 reactions, and they proceed very quickly. The first two reactions serve as a source of material for the third and fourth, which at temperatures thermonuclear explosion It takes 30-100 times faster and give a greater energy output. Therefore, the obtained helium-3 and tritium are immediately spent.

The nuclei of atoms is charged positively, and therefore pushed apart from each other. So that they can react, they need to push the "forehead in the forehead", overcoming the electrical repulsion. This is possible only if they will move at high speed. Atom speed is directly related to the temperature, which should reach 50 million degrees! But it is not enough to heat the deuterium to such a temperature, you need to still hold it from the waken a monstrous pressure of about a billion atmospheres! In nature, such temperatures are found only in the kernel of stars.

As often, unfortunately, useful inventions are often used for bad purposes. This also applies to the use of a chain fission reaction. The fight against the spread of atomic weapons comes with varying success. The greatest danger represents the possession of atomic weapons from authoritarian regimes and, especially for terrorists. Consider different types Atomic bombs and dangers associated with the possibility of spreading the technologies of their production.

Uranium-235 bomb

Atomic bomb can be made from U-235, PU-239 and U-233. Of these, only U-235 exists in nature. PU-239 and U-233 are obtained by the bombardment of other isotopes neutrons.
The easiest way can be made atomic bomb from uranium. For this you do not need a reactor. For example, for this you need to have the required amount of natural uranium, gas centrifuges. Uranium is translated into a gaseous state - uranium hexafluoride UF 6, which is passed through centrifuges. The degree of separation is determined by the number of individual centrifuges collected in the cascade. "A little" patience, and you have an armory uranium (\u003e 90% 235 U). In order to create a uranium bomb without plutonium), it is necessary about 15-20 kg of weapons uranium.
However, although in principle the process of enrichment of uranium is known in order to get sufficient number Highly enriched uranium required raw materials, qualifications, infrastructure and a large amount of energy. So even the receipt of highly enriched uranium terrorists is very unlikely. Most likely, he will try to just steal. Thus, countries with reserves of weapons uranium must strictly follow their repository. The operation of weapons uranium is ranked only to countries with a fairly developed technological basis.
In addition, it is necessary to make a bomb from the enriched uranium. The most primitive atomic bomb - so-calledbomb "Cannon" type.

Bomb "Cannon" type
The bomb "cannon" type is simple in design. In it, one "piece" U-235 "is shot with the help of an appropriate charge in another" piece ", with a critical mass. As a result, a chain reaction occurs. Such a bomb is inefficiently uses the fissile material; only 1.4% of highly enriched uranium in the bomb of this type is divided. This bomb was dropped on Hiroshima. It is too large for a rocket however, it can be delivered, for example, by plane.

Plutonium-239 bomb

Plutonium is a by-product of all reactors. However, in order to use it as a fissile material, it must be chemically cleaned from the remnants of highly active waste. This is an expensive and dangerous process requiring special knowledge and equipment.

Plutonium is formed in a nuclear reactor with the bombardment of U-238 thermal neutrons

PU-239 is used to produce nuclear weapons. Sections of division and scattering, as well as the number of neutrons during division in PU-239 more than in U-235 and, accordingly, less critical mass, i.e. To implement a self-sustaining reaction of plutonium division, it is necessary less than uranium. For a plutonium atomic bomb, it is usually necessary 3-5 kg \u200b\u200bof PU-239.
Because of the relatively small half-life (in comparison with U-235), PU-239 due to the radiation emitted by them noticeably heats up. The heat dissipation of PU-239 - 1.92 W / kg. So, a well-insulated piece of plutonium in two hours heats up from room temperature up to 100 o. This, naturally, creates difficulties when designing a bomb. The physical properties of plutonium are such that in the bomb of the cannonal type, it is not possible to quickly connect two pieces of plutonium in order to form a critical mass. For plutonium you need to apply a more complex scheme.

Implosion type bomb
In the center of the Implosion bomb there is a plutonium high-enriched uranium or a mixture thereof. The explosion directed into the plutonium corner is implemented using a special lenses system that are triggered simultaneously. Plutonium is strong and evenly compressed. The mass becomes critical. However, the simple compression of plutonium to the critical mass does not guarantee the beginning of the chain reaction. For this, neutrons are needed from the neutron source, which is located in the center of the device and simultaneously with compression irradiates plutonium.
Plutonium extracted from irradiated fuel and the reactor used in the reactor becomes less suitable for the production of weapons due to the increase in PU-238, PU-240 and PU-242 in it.
The main harmful admixture for weapons plutonium is PU-240 due to its high speed of spontaneous division. It is more than that of PU-239 30000 times. Only 1% PU-240 in the mixture produces such a number of neutrons that an explosion is possible in the implosion system. The presence of the latter in large proportions significantly complicates the task of designing a reliable government with specified characteristics (rated power, safety during long-term storage, etc.)
Weapon plutonium, characterized by a very high (over 90%) content of a dividing isotope 239 PU and a small content of 240 PU isotope (up to ~ 5%).
"Civilian" plutonium allocated when recycling (reprocessing) of spent fuel nuclear reactors NPP and characterized by the average ratio of the content of isotopes 239 (60%) and 240 (40%). The use of "civil" plutonium for the manufacture of nuclear warheads is in principle possible.

Uranium-233 bomb

In countries where there is little uranium, but a lot of thorium (for example, India), it is of interest to obtain a delaying isotope U-233 using a chain of reactions:

As an explosive material 233 U is almost as effective as 239 PU. Completes the situation in the military application of 233 U impurities 232 U, whose subsidiaries are strong gamma sources, which complicates work with it.
232 U is formed as a result of the reaction.

During the creation of atomic weapons, under the Manhattan project, work was at the same time to create two nuclear bombs - uranium and plutonium.

After testing the first nuclear charge "Gadget" (the prototype of the plutonium bomb "Fat" - Fatman) the following, was ready to use the uranium "baby" (Littleboy). It was he who turned out to be discarded on Hiroshim on August 6, 1945. The manufacture of another "baby" would require the months of accumulation of uranium, so the second burned bomb became "fat man", assembled on Tinian Island shortly before its use.

The initial assembly of Fat Man "And was on the basis of the Navy Solvelles, California. The final selection and installation of the plutonium kernel was produced on Tinian Island (Tinian), in the Pacific Ocean, where the construction of the first combat plutonium charge was completed. The second after Hiroshima, the blow was initially It would be imposed on the kokura (Kokura), a few days after the first attack, however, due to weather conditions, the city of Nagasaki was subjected to bombardment.

Uranium Atomic Bomb Little Boy.
Uranium charge in the bomb consists of two parts: targets and shells. The shell of diameter 10 and a long 16 centimeters is a set of six uranium rings. It contains about 25.6 kg - 40% of total uranium. Rings in the projectile are supported by a tungsten carbide disk and steel plates and are inside the steel case. The target has a mass of 38.46 kg and is made in the form of a hollow cylinder with a diameter of 16 cm and a length of 16 cm. Structurally it is made in the form of two separate halves. The target is mounted into the housing that serves as a neutron reflector. In principle, the amount of uranium is used in the bomb gives a critical mass and without a reflector, however, its presence, like the manufacture of a projectile from more enriched uranium (89% U-235) than the target (~ 80% U-235), allows you to increase the charge power.

The process of enrichment of uranium occurred in 3 stages. Initially, the thermal diffusion installation took place the enrichment of natural ore (0.72% of uranium) to 1-1.5%. This was followed by a gas diffusion unit and the last stage - an electromagnetic separator, which already produced uranium isotopes. For the production of "kid" it took 64 kg of enriched uranium, which is ~ 2.5 critical masses. By the summer of 1945, about 50 kg of 89% U-235 and 14 kg of 50% were accumulated. As a result, the total concentration was ~ 80%. If you compare these indicators with a plutonium core, the mass of PU-239 in which there were only 6 kilograms containing about 5 critical masses, the main disadvantage of the Urango project becomes visible: the difficulty of ensuring the high supercriticality of the dividing substance, as a result of which low weapons efficiency.

To prevent accidental occurrence of the chain reaction in the target, a borovascular cap is contained, and the projectile is embedded in the Boron shell. Bor is a good neutron absorber, thus increases safety during the transportation and storage of a uninterrupted ammunition. When the projectile reaches the target, his shell departs, and the plug in the target is thrown out of it.

The assembled bomb membrane consists of a tungsten carbide housing (serving neutron reflector), surrounded by a steel jacket with a diameter of approximately 60 cm. total weight Such a design is about 2.3 tons. A carbide housing is installed in the shirt drilled in the shirt, in which the target is mounted. In the bottom of this holes there may be one or more beryllium-polony initiators. The trunk, according to which the uranium shell moves is firmly attached to a carving to the steel target body, it is borrowed from 75 mm of an anti-aircraft gun and crushed in the size of the projectile to 100 mm. The length of the trunk is approximately 2 m, the mass is 450 kg, and the government part is 34 kg. Smokeless powder is used as a throwing explosive. The speed of the projectile in the trunk reaches about 300 m / s, the action of at least 300 kN is required to bring it in motion.

Little Boy was extremely unsafe in storage and transportation bomb. Detaconation, even a random, throwing explosive (leading the projectile), causes a nuclear explosion. For this reason, the air observer and service specialist S. Parsons decided to load gunpowder to the bomb only after takeoff. However, with a sufficiently strong impact, the projectile may come into motion and without the help of powder, which is capable of explosion from several tons to full power. Little Boy is a danger and when entering the water. Uranium, located inside - several critical masses in total, separated by air. If you get inside the water, it can play the role of an intermediary, leading to a chain reaction. This will lead to a rapid melting or a small explosion with a large number of radioactive substances.

Assembly and use of Little Boy.
The first components of the projectile were finished in Los Alamos on June 15, 1945, they were fully manufactured by July 3.

On July 14, Little Boy and the uranium projectile to it were shipped to the Indianapolis vessel and the 16th went on about. Tinian, Mariana O-Wa. The ship arrived on the island on July 26.

On July 24, the manufacture of the target for the bomb and the 26th of these components were completed by three C-54 aircraft from Albuquerque and arrived at Tinian on the 28th.

July 31 The target with the projectile is installed inside the bomb. The nuclear attack is scheduled the next day, August 1, but the approaching Typhoon made the operation for 5 days.

August 6:
00:00 Last meeting, the goal is Hiroshima. Pilot - Tibbets (Tibbets), 2nd pilot - Lewis (Lewis).
02:45 The bomber takes off.
07:30 Bomb is completely ready for reset.
08:50 The plane flies over the Japanese Island of Sikoku.
09:16:02 Little Boy explodes at an altitude of 580 m. Explosion power: 12-18 CT, in late estimates - 15 CT (+/- 20%).

With such a power of the explosion, the height on which it was undermined, optimal for pressure of the shock wave 12 PSI (pounds / square inch), i.e. To maximize a pressure subjected to 12 PSI or greater. To destroy the buildings of the city, there is enough pressure in 5 PSI, which corresponds to the height of ~ 860, thus, when installing such a height of the victim and destruction might be even more. Due to the ambiguity in determining the power and large number of reasons that can cause a decrease in the power of the explosion, the height was selected moderately low, as in the case of a small charge. The height of 580 m is optimal for an explosion in 5 CT.

Plutonium atomic bomb Fat Man.

The bomb kernel is a set of spheres invested in each other. Here they are listed in the order of nesting, dimensions are given for external radii of spheres:

* Explosive shell - 65 cm,
* "Pusher" / neutron absorber - 23 cm,
* Uranium housing / neutron reflector - 11.5 cm,
* Plutonium kernel - 4.5 cm,
* Beryllium-polonium neutron initiator - 1 cm.

Neutron initiator.
The first stage is a neutron initiator, also called urchin (urchin), is a beryllium spherical shell, a diameter of 2 cm and a thickness of 0.6 cm. Inside it is a beryllium liner with a diameter of 0.8 cm. The total design of the design is about 7 grams. On the internal surface Shells made 15 wedge-shaped slots, a depth of 2.09 mm. The shell itself is obtained by hot pressing in the atmosphere of carbonyl nickel, the surface of it and the inner sphere is covered with a layer of nickel and gold. On the inner sphere and cream in the shell, 50 Curi polonium-210 (11 mg) was besieged. The gold and nickel layers protect beryllium from alpha particles emitted by Polonia or surrounding the initiator plutonium. The initiator is enshrined on the bracket inside the cavity with a diameter of 2.5 cm in the plutonium core.

Urchin is activated when the charge center shock wave is reached. When the shock wave reaches the walls of the inner cavity in plutonium, the shock wave of evaporated plutonium affects the initiator, the smile gap with polonium and creating the Munro effect (MUNROE) - strong jets of substances that quickly mix polonium and beryllium from the external and internal spheres. Alpha particles emitted by PO-210 are absorbed by beryllium atoms, which in turn emit neutrons.

Plutonium charge.
The nineisantimeter sphere, with a cavity in the center size of 2.5 cm for the neutron initiator. This form of charge suggested Robert Christy to reduce asymmetry and instability during implosion.

Plutonium in the kernel is stabilized in a low-density delta phase (density 15.9) with the help of fusion of it with 3% gallium in the amount of substance (0.8% by weight). The advantages of using the delta phase compared to a more dense alpha phase (density 19.2) are that the Delta phase is forging and puffy, while the alpha phase is broken and fragile, in addition, plutonium stabilization in the delta phase allows Avoid shrinkage when cooling and deforming the workpiece after casting or hot processing. It may seem that the use of a lower density material can be disadvantaged for the nucleus, since the use of a more dense material is preferable because of increasing efficiency and reduce the amount of the required plutonium, but this turns out to be not quite so. Delta-stabilized plutonium is subjected to a transition to the alpha phase at a relatively low pressure of tens of thousands of atmospheres. The pressure of several million atmospheres arising from an implosion explosion makes this transition along with the rest of the phenomena arising from such a compression. Thus, with plutonium in the delta phase there is a greater increase in density and greater entry of reactivity than this would happen in the case of a dense alpha phase.

The kernel is collected from two hemispheres, probably originally cast in the workpiece, and then treated with hot pressing in the atmosphere of carbonyl nickel. Since plutonium is chemically very active metal, but, moreover, representing a danger to life, each hemisphere is covered with a layer of nickel (or silver, as reported for the Gadget kernel "a). This coating has created a nuisance with the Gadget kernel" A, since rapid electroplating Plutonium with nickel (or silver) led to the formation of shells in the metal and unsuitable it for use in the kernel. Glorious grinding and layering layers of gold restored defects obtained by policies. Nevertheless, the thin goldley layer (about 0.1 mm thick) between the policies was in any case the necessary part of the project, which serves to prevent the premature penetration of the shock wave jets between the polishes, which could prematurely activate the neutron initiator.

Uranium housing / neutron reflector.
Plutonium charge is surrounded by a body from natural uranium weighing 120 kg and diameter 23 cm. This body forms seven centimeter layer around plutonium. The thickness of the uranium is due to the task of preserving neutrons, so, the layer of several centimeters is sufficient to ensure neutron braking. A thicker housing (exceeding 10 cm thick) further provides significant preservation of neutrons for the entire structure, however, the effect of "temporal absorption" inherent in the rapid exponentially developing chain reactions reduces the benefits of using a thicker reflector.

About 20% of the bomb energy is allocated due to the rapid division of the uranium case. The kernel and the case form together the minimum subcritical system. When the assembly compression occurs with the help of an implosion explosion to 2.5 times compared with the usual density, the kernel begins to contain about four-five critical masses.

"Pusher" / neutron absorber.
The surrounding uranium layer of aluminum, a thickness of 11.5 cm weighs 120 kg. The main purpose of this sphere, called the "pusher", is to reduce the action of the Taylor's wave, the rapid decrease in the pressure occurring behind the detonation front. This wave tends to increase with implosion, causing an increasingly rapid pressure drop in the designer of the detonation front at one point. A partial reflection of the shock wave occurring on the border of the explosive section (composition "B") / aluminum (due to the difference in densities: 1.65 / 2.71) sends the secondary front back into explosives, suppressing the Taylor's wave. It enhances the pressure of the last wave, increasing compression in the center of the nucleus.

The aluminum "pusher" contains in itself and the proportion of boron. Since the boron in itself is a fragile non-metallic substance, difficult to use, it is very likely that it is contained in the form of a convenient to process alloy with aluminum, called Borax (35-50% boron). Although his overall share in the shell is small, Bor plays the role of the neutron absorber, preventing from entering into the plutonium-uranium assembly of neutrons departing from there, slowing down in aluminum and explosives to heat velocities.

Explosive shell and detonation system.
Explosive shell is a layer of a breezed explosive. Its thickness is about 47 cm, and the mass of at least 2500 kg. This system contains 32 explosive lenses, 20 of which are hexagonal, and 12 are pentagonal. The lenses are connected together according to the sample of a soccer ball, forming a spherical explosive assembly, about 130 cm with a diameter. Each has 3 parts: two of them are made from an explosive (explosive) at a high speed of detonation, one - low. The most extreme part of the fasteptonizing explosives has a cone-shaped recess, filled with low detonation rebneu. These conjugate parts form a valid lens capable of creating a round, growing shock wave aimed at the center. The inner side of the fasteptonizing centuries almost covers the aluminum sphere to enhance the convergent strike.

The lenses were made by the exact casting, so the explosive should have been melted before use. The main fast-moving explosives was the "Composition B", a mixture of 60% hexagena (RDX) is very fast-moving, but poorly melting bibs, 39% of TNT (TNT) - well exploding and easily melting centuries and 1% wax. The "slow" explosions was Baratol - a mixture of trotyl and barium nitrate (the fraction of Tola is usually 25-33%) with 1% wax as a binder.

The composition and density of lenses were accurately controlled and remained unchanged. The lens system was adjusted with a very low tolerance, so that its parts were connected to each other with an accuracy of less than 1 mm to avoid heterogeneity in the shock wave, but the lenses surface alignment was even more important than fitting them to each other.

To obtain a very accurate synchronization of detonators, standard detonators had no combinations of primary / secondary explosives and electrically heated conductions were used. These conductors are a segment of a thin wire, which instantly evaporate from the current dropped from a powerful condenser. An explosive of the detonator explosive is occurring. The discharge of the capacitor battery and the evaporation of the wire in all detonators can be produced almost simultaneously - the difference is +/- 10 nanoseconds. back side Such a system is a need for large batteries, a high-voltage power supply and a powerful bank of capacitors (called X-Unit, about 200 kg weighing) intended for simultaneous response of 32 detonators.

The finished explosive shell is placed in the case of duralumin. The design of the housing consisted of a central belt collected from 5 treated duralumin castings, and the upper and lower hemispheres, forming the finished shell.

The final stage of the assembly.
The final project of the bomb provides for a special "cover" through which the dividing materials are laid at the end. The charge can be made entirely, except for the insertion of plutonium with the initiator. For security purposes, the assembly is completed immediately before practical application. Dulely semisfer is removed along with one of the explosive lenses. The neutron initiator is installed between plutonium semisers and is fastened inside a 40-kilographed uranium cylinder and, then, all this design is embedded inside the uranium reflector. The lens returns to its place, the detonator is connected to it, the cover is screwed on top to its place.

Fat Man represented a serious danger in terms of delivery and storage in the ready-to-use state, however, even in the most worst case, the danger was still smaller than the Little Boy. The critical mass of the core with the uranium reflector is 7.5 kg of plutonium for delta phase, and only 5.5 kg for the alpha phase. Any random detonation of an explosive shell can lead to a compression of a 6.2-kilographed fat manner "And in the supercritical alpha phase. The estimated power of the explosion from such an unauthorized charge of charge will be from tens of tons (roughly speaking an order of magnitude more than the charge of explosives in the bomb) to Couples-other hundreds of tons of trotyl equivalent. But the main danger lies from the flux of penetrating radiation during an explosion. Gamma rays and neutrons, can cause death or severe illness much further zone of the shock wave. So, a small nuclear explosion in 20 tons will cause death Dose of irradiation in 640 Bar at a distance of 250 m.

Transportation of Fat Man "And for safety reasons has never been carried out in a fully assembled form, the bombs were completed immediately before use. As a result of the complexity of the weapon, at least a couple of days was required to this process (taking into account intermediate checks). The collected bomb could not be in operational condition due to the discharge of X-Unit batteries "a.

The outlines of the combat plutonium bomb mainly consist of the design of the experimental Gadget "A, packed in a steel shell. Two half of the steel ellipsoid are attached to the bandage of an explosive system along with the X-Unit" Ohm, batteries, fuses and starting electronics are placed on the front of the shell.

As in the Little Boy, the high-rise solder in Fat Man "e serves a radar rangefall system" Atput "(Archies - its antennas can be seen on the side of the photos of Little Boy" I). When the charge is reached the desired height above the ground (installed at 1850 + -100 feet) it gives a signal to detonation. In addition to him, the bomb is also equipped with a barometric sensor that prevents the explosion above 7,000 feet.

Combat use of a plutonium bomb.
The final assembly of the fat man took place on about. Tinian.

July 26, 1945 Plutonium kernel with the initiator was sent by the C-54 aircraft from the Kirtlend airbase to Tinian.

July 28, the kernel arrives on the island. On this day, three B-29 leave from Cyrtlend to Tinian with three pre-assembled Fat Man "Ami.

August 2 - Arrival B-29. The date of bombardment is defined as August 11, the goal is arsenal in the kokura. The non-nuclear part of the first bomb was ready for August 5th.

August 7 comes a forecast for flights adversely for flight 11, the flight date is shifted by 10, then on August 9. Due to the date shift, accelerated work assembly work is underway.

8th in the morning Fat Man's assembly "And ends, by 22:00 it is loaded into the B-29" block "s car".

August 9:
03:47 The plane takes off from Tinian, the goal is defined as a Kokochsky arsenal. Pilot - Charles Sweeney.
10:44 Time is flown to the cocure, but the goal is not enough in conditions of poor visibility. the fire anti-aircraft artillery And the appearance of Japanese fighters forced to stop searches and turn toward the spare goal - Nagasaki.
Over the city turned out to be a layer of clouds - like over the cockurio, the fuel remained only for one occasion, so the bomb was reset in the first suitable lumen in the clouds a few miles from the appointed goal.
11:02 There is an explosion at an altitude of 503 m near the border of the city, the power according to the measurements of 1987 - 21 CT. Despite the fact that the explosion occurred on the border of the city's populated part, the number of victims exceeded 70,000 people. Gitzubishi's weapons were also destroyed.

(Nowadays the Democratic Republic of the Congo), in Canada (Big Bear Lake) and in the United States (Colorado).

Unlike most modern bombs made on the implosive principle, the "kid" was a bomb of a cannon. A cannon bomb is easy to calculate and manufacture, practically does not know failures (therefore, the exact drawings of the bomb still are still classified). The reverse side of such a design is low efficiency.

16.4 cm harvested to 1.8 m was used, while the uranium "target" was a cylinder with a diameter of 100 mm and weighing 25.6 kg, which the cylindrical "bullet" of 38 had the cylindrical "bullet" with a slot. 5 kg with the corresponding internal channel. Such "intuitively incomprehensible" design was made to reduce the neutron background of the target: it was not close to it, and at a distance of 59 mm from the neutron reflector ("Tepper"). As a result, the risk of premature starts of the chain reaction of division with incomplete energy release decreased to several percent.

Despite the low efficiency, the radioactive contamination from the explosion was small, since the explosion was produced in 600 m above the earth, and the unreacted uranium itself is weakly caused compared to nuclear reaction products.

The fuses in this bomb were inserted directly in an airplane, in Bombotsek, 15 minutes after the takeoff, to minimize the danger of the consequences of the unsuccessful takeoff. At the same time, it was likely that it could work abnormally.

The point in World War II was given by the United States, namely, President Harry Truman, at the moment when the atomic bomb, discarded on Hiroshima, exploded over the heads of thousands of Japanese.

This tragic event and at the same time a large technological breakthrough preceded years of research, the work of hundreds of outstanding scientists and technicians around the world, dozens of lives that were lost as a result of the effects of radiation.

And only by the will of the case, the first, who managed to apply the result of research in the field of atomic energy as a weapon, were Americans. Hiroshima, Nagasaki, nuclear bomb - these words have become practically synonymous when we are talking about weapons of mass destruction. New weapons, the symbol of the arms race - the atomic bomb on Hiroshima and Nagasaki brought only pain and death.

What was the atomic bomb (Hiroshima) created to destroy human lives, With so cute name "Little Boy" (eng. Kid)? Who was the creator of this innovative weapon used on the Japanese cities of Hiroshima and Nagasaki? The capacity of the bomb, its characteristics are the questions, the answers to which we will try to give in this article.

Atomic bomb Hiroshima. What started?

At the turn of 1938 and 1939, the fact of dividing the uranium core was opened and the critical mass of uranium-235 isotope was determined. In those years, scientific circles different countries Tightly collaborated, but the growing stress in the world raised joint research.

In the United States were also interested in this topic. World physics Eugene Wigner and Leo Sorope wrote a letter to Franklin Roosevelt on behalf of Einstein. It reported that fascist Germany conducts research, as a result of which a bomb will be made incredible power. In this regard, the authors of the letter called on the American president to speed up the accumulation of uranium ore and increase the financing of atomic energy projects, as the first atomic bomb should be made in the United States. Hiroshima and Nagasaki will soon become a landfill for testing its power.

The US government emerges the necessary measures. The research uranium committee is reformatted, and on September 17, 1943, the Secret Program "Project Manhattan" opens. Already very soon the atomic bomb will be created. Hiroshima will experience her action on himself. For research, they led the Colonel Leslie Groves and Robert Oppenheimer (scientific part), physician scientists from all over the world, people, techniques and other specialists were invited. Many of them were refugees from fascist Germany.

In total, in the project, as a result of which the nuclear bomb will be reset on Hiroshima, about 130 thousand employees took part. Among them are more than a dozen laureates of the Nobel Prize.

Birth of "Baby"

Uranium isotope 235 in ore of natural origin is contained in the amount of only 0.7%.

To obtain the critical mass required to overcome the critical mass in 10 kg of Uranium-235, the National Laboratory in OK-Ridge has developed ways to enrich ore, and the raw materials for the manufacture of the uranium bomb "Kid" was mined from several deposits:

  • Belgian Congo (territory of modern Democratic Republic Congo in Central Africa);
  • Big Bear Lake in Canada;
  • Colorado State (USA).

There is an assumption that half of the global stock of uranium, located in the Belgian Congo, until the end of the 30s was burned by France. On the basis of a well-equipped laboratory in De France, European scientists did not have time to bring research to the end, as France fell in 1940. After, uranium reserves were removed in the United States.

IT'S IMPORTANT TO KNOW:

A large team of scientists worked on the project for the creation of atomic weapons in the States, but his "father" is considered Otto Openedheimer. If it were not for his genius, the nuclear bomb would not fall on Hiroshima, and the outcome of World War II would be different. Later he will actively oppose the use of atomic weapons. Opengeimer will try with all the forces to not repeat the "New Hiroshima", the bomb of this type was not reset.

The mechanics of the bomb explosion lay down a cannon system. Its developer was William Parson. This is a fairly simple principle. Two parts having a doctritic mass on certain speed are connected, and an explosion occurs. But, even having achieved a critical mass, in which the detonation of uranium, two pieces of this radioactive material would not have a destructive force. It was necessary to provide a dense shell, which would prevent the "weathered" neutrons.

The first, not a tested sample - a Uranium bomb (Hiroshima; Nagasaki received a plutonium bomb already tested on the landfills) "Kid", after dialing need quantity Radioactive filler, was rebelled to the city of Hiroshima. The bomb possessed a fairly low efficiency of the charge, but it was enough to carry hundreds of thousands of human lives.

What was the bomb discarded on the city of Hiroshima?

The blown bomb in Hiroshima carried 64 kilograms of rich up to 80% uranium-235. Of these, 25 kg accounted for the "target", and the rest of the mass on the "bullet", which moved in a gun barrel with a diameter of 76.2 mm at a speed of 300 m / s from an explosion of powder charge.

In order for the capacity of the bomb in Hiroshima to meet the requirements for the devastating force, it took more than 12 tons of uranium ore, which, during the one and a half months of continuous operation, enriched an industrial giant in OK-Ridge. The length of the "kid" was 3 m 20 cm, diameter - 71 cm. The massive case made of heavy alloy steel, standard for American air bombs of that period a bulky tail, plus the rest of the equipment gave a total of 4090 kg, heading for the city of Hiroshima. The capacity of the bomb was to be sufficient for massive destruction.

Thanks to the elongation and anterior center, the airbomb had a resistant trajectory, and as a result, high accuracy of hitting. The power of the atomic bomb dropped on Hiroshima was 18 kilotons in Ttatile Equivalent. In the future, the capacity of the bomb dropped on Hiroshima will be extremely small. Atomic weapons Future generations have much higher rates of destructive power.
The capacity of the bomb dropped on Hiroshima was due not only to the number of uranium charge, but also additional mechanics.

Properties were tasks:

  • In operation, the atomic bomb (Hiroshima) must be safe, unauthorized detonation is invalid;
  • make so that the falling bomb on Hiroshima exploded at an altitude of 500 - 600 meters above the ground;
  • if something goes not according to plan, and the bomb on Hiroshima will fall without exploding, the self-destruction of the charge must occur so that the technologies do not get the enemy.

For these purposes, four main systems were developed:

  • Archie's altimeters, developed for the US Air Force, ensured the detonation of the bomb at the desired height, and there were enough 2 indicators from the 4-weeds. Interesting fact It is that the sensitive antennas of altimeters could not be removed from the bomb and reinstall. Therefore, all American aviation over the Japanese Islands in the days when the atomic bomb on Hiroshima and Nagasaki were on the way, it was forbidden to create radiocomers.
  • The barometric fuse and timer served to prevent unintended self-examination. The fuse did not allow the explosive chains at heights of more than 2135 m. The timer was blocked for 15 ° C after the bombs reset the barometric data reflected from the carrier aircraft.
  • The automation unit when the altimeters is triggered, launched the detonator of the cannon system of the uranium charge.
  • In case of unforeseen malfunctions, if the bomb does not explode over the city of Hiroshima, the usual fuse will work at the ground.

Released atomic bomb on Hiroshima and Nagasaki. What is the difference?

Dropped into the city of Hiroshima bomb based on uranium, it was extremely expensive for production. "Project Manhattan" parallel to the development of a bomb based on Plutonium-239 (strongly radioactive). The nuclear bomb of Hiroshima was, as mentioned above, a cannon-type, for plutonium, it was necessary to have another solution. The shelf of plutonium charge in the shells was surrounded by 64-detonators. All this was placed in a metal ball. Detonation inside the sphere, increasing the density of plutonium to critical, causing an explosion. The mechanics was the same as the atomic bomb was carried (Hiroshima) "Kid".

The power of the atomic bomb in Hiroshima was significantly lower. "Tolstyak", intended for Nagasaki, had a power of 22 kilotons in TNT equivalent. But the destruction he brought much less due to the inaccuracies of the aiming and configuration of the city.

A discarded nuclear bomb on Hiroshima and Nagasaki was supposed to force Japan to capitulate. The United States has achieved its price of thousands instantly selected in atomic lights of lives, diseases and suffering many thousands of many thousands of people in the cities of Hiroshima, Nagasaki. The atomic bomb used in Japan led to the end of World War II and laid the beginning of the Cold War and Nuclear Energy Ave.

According to some information, another atomic bomb could exist. Hiroshima and Nagasaki became the first in the list of victims. The capacity of the bomb (on Hiroshima had about 15 - 18 kilotons), which could be the third, was several times higher. But for the reasons unknown to us, her trail is lost.