This can be achieved by the control of the critical mass or critical dimensions, in principle, the simplest atomic bomb uses the so-called gun structure, two pieces of uranium that are both smaller than the critical mass, separated by a certain distance, do not cause an explosion, and when they are combined, they are greater than the critical mass and an explosion occurs immediately.

But if they are put together slowly, then soon after the chain reaction begins, the energy generated is enough to blow them away, and to stop the chain reaction, the explosive power of the atomic bomb and the utilization rate of the nuclear charge are very small, which is somewhat similar to the situation in the case of a supercritical accident explosion of a reactor, so the key problem is to make it possible for them to come together very quickly.

This makes it possible to place one part of the uranium at one end and the other part inside the "barrel", which, with the help of high explosives, brings them together completely and very quickly, creating supercriticality and producing a highly efficient explosion.

To reduce neutron loss, the nuclear charge has a neutron reflector layer on the outside; To delay the dispersion of the nuclear charge, the atomic bomb had a solid casing.

In August 1945, the atomic bomb (codenamed "Little Boy") dropped by the United States on Hiroshima, Japan, was a gun-like structure, weighing about 4,100 kilograms, with a diameter of about 71 centimeters and a length of about 305 centimeters.

The nuclear charge is uranium-235, the explosive power is about 14,000 tons of TNT equivalent, in the gun structure, each nuclear charge can not be too large, at most it can only be close to the critical mass, and can never be equal to or exceed the critical mass.

Therefore, when the two nuclear charges are combined, the total mass can only be nearly twice as much as the critical mass at most. This limited the explosive power of the atomic bomb.

In addition, in the gun structure, although the two nuclear charges are closed at high speed, the time that elapses during the closing process is still too long, so that the neutrons released by spontaneous fission cause an explosion before the two nuclear charges are fully combined.

This "premature ignition" causes inefficient explosion, so that the utilization rate of nuclear charge is very low, one kilogram of uranium-235 (or plutonium-239) is all fission, about 18,000 tons of TNT equivalent energy can be released, and the nuclear charge of an atomic bomb is generally 15~25 kilograms of uranium-235 (or 6~8 kilograms of plutonium-239), so that the utilization rate of the nuclear charge of the "little boy" is less than 5%.

The density of uranium at normal pressure is about 19 g/cm. At high pressure, uranium can be compressed to a higher density. Studies have shown that for a given fission material, the higher the density, the smaller the critical mass. According to this characteristic, in parallel with the development of the gun structure, an implosion type was developed.

In the gun structure, the atomic bomb achieves supercriticality by suddenly increasing the amount of fissile material at normal density, while the implosion structure atomic bomb achieves supercriticality by increasing the density by suddenly increasing the pressure.

In the implosion structure, a high explosive with a high explosion velocity is made into a spherical device, and a nuclear charge less than a critical mass is made into a small ball, which is placed in the explosive. Through the synchronous ignition of the electric detonator, the explosives are detonated at each point at the same time, generating a powerful centripetal focused compression wave (also known as an implosion wave), so that the peripheral nuclear charge closes to the center at the same time, so that its density is greatly increased, that is, it is greatly supercritical.

Then use a controllable neutron source and wait until the compression wave effect is at its maximum, and then "ignite" it. This results in a self-sustaining chain reaction, resulting in an extremely violent explosion.

The advantage of implosion structure over gun structure is that the compression wave effect takes much less time than the time it takes for the gun structure to close, so the probability of "premature ignition" is greatly reduced. In this way, the implosion structure can use fissile materials with a high probability of spontaneous fission, such as plutonium-239, as a nuclear charge; At the same time, the utilization efficiency is greatly increased.

The atomic bomb dropped by the United States on Nagasaki, Japan (codenamed "Fat Man") used an implosion structure and used plutonium-239 as a nuclear charge. The bullet weighs about 4,500 kilograms, the diameter of the projectile is about 152 centimeters at the thickest point, the length of the projectile is about 320 centimeters, and the explosive power is estimated to be 20,000 tons of TNT equivalent.

The further development of the atomic bomb was the hydrogen bomb, or thermonuclear weapon. Hydrogen bombs use the enormous amounts of energy emitted by certain light nuclear fusion reactions. Its charge can be deuterium and tritium, as well as lithium deuteride-6, and these substances are called thermonuclear materials.

In terms of material per unit weight, the nuclear fusion reaction emits more energy than the fission reaction, and there is no so-called critical mass limit, so the explosive power of the hydrogen bomb is greater, generally hundreds to thousands of times greater than that of the atomic bomb.

However, thermonuclear reactions can only be carried out at extremely high temperatures (tens of millions of degrees), and such high temperatures can only be produced when an atomic bomb explodes, so the hydrogen bomb must use the atomic bomb as a "detonator" to ignite the thermonuclear material.

When a hydrogen bomb explodes, it releases a large number of high-energy neutrons that can cause uranium-238 to fission. Therefore, a layer of uranium-238 on the outside of a general hydrogen bomb can greatly increase the explosion power. The explosion of this kind of nuclear bomb goes through three processes: fission, fusion, and fission, so it is called a "three-phase bomb." It is characterized by low cost, high power, and high radioactive contamination.

There is also a new type of nuclear bomb, the so-called neutron bomb, the neutron bomb may actually be a small hydrogen bomb, but the fission component in this small hydrogen bomb is very small, and the fusion component is very large, so the effect of shock wave and nuclear radiation is very weak, but the neutron flow is extremely strong.

It relies on a strong stream of neutrons to kill and is said to be able to "kill without destroying things", and the atomic bomb can be made from uranium or plutonium, but plutonium is made from uranium.

The hydrogen bomb had to be introduced with an atomic bomb. Therefore, in the final analysis, the manufacture of nuclear weapons, thermonuclear weapons, cannot be done without uranium.

Thus, in the past, today, and for a long time to come, the heaviest natural elements are important, first of all, in military necessity.

To manufacture an atomic bomb, it is necessary not only to solve a series of scientific and technological problems in the development of weapons, but also to be able to produce the necessary nuclear charges uranium-235 and plutonium-239, and the abundance of uranium-235, the isotope uranium-235 in natural uranium, is only 0.72 percent, and it must be increased to more than 90 percent according to the design requirements of the atomic bomb.

In addition to the production of uranium-235, plutonium-239, and other nuclear materials, the development of the nuclear warhead itself must be coordinated with the development procedures of the entire nuclear weapons system.

The specific development process is roughly arranged as follows:

Start with the planning phase; After the preliminary study or feasibility study of key technical topics and components, several design schemes including weight, size, form, power, nuclear materials, nuclear test requirements, development period, and funding are formed.

Then, after demonstration, comparison and evaluation, the design scheme is selected, and the tactical and technical indicators are determined. Then, the model study design and various simulation tests are carried out.

Process test and trial production, through nuclear test to test the rationality of the design, and finally to achieve the design finalization, process finalization and approved production.

To carry out this work, it is necessary to secretly organize the recruitment of specialized scientific and technological teams and to equip them with the necessary test sites, including nuclear test sites.

After the weapons are delivered to the troops, the R&D and production departments also provide services such as maintenance, repair, and replacement of parts, make necessary improvements according to the feedback information, and be responsible for their decommissioning, processing, and renewal.

In order to do a good job in the design of a nuclear warhead, it is necessary to have an in-depth understanding of its reaction process, to understand the conditions and various physical parameters that it must have, and to grasp the internal relations and laws of change of many factors.

To this end, it is necessary to conduct research on a series of scientific and technological issues in multiple disciplines, such as nuclear physics, neutron physics, high-temperature and high-pressure condensed matter physics, supersonic fluid mechanics, detonation, computational mathematics, and materials science.

Zhao Weidong also proposed that in the process of development, special attention should be paid to the following links:

It is necessary to arrange for the New York Computer Company in the United States to immediately begin to develop a fast, large-capacity electronic computer for the calculation and simulation of nuclear reactions to carry out theoretical research and calculation of the reaction process, and such calculations should be as close as possible to the actual situation, so as to find the optimal scheme from a variety of assumptions or design schemes, so as to save costs and reduce the number of nuclear tests.

Of course, minimizing the number of nuclear tests is not just about saving money, but more importantly, because the world's major powers are eyeing up and trying to avoid unnecessary conflicts, and they are certainly not happy to have another country with nuclear forces.

In accordance with the requirements of the program or indicators, the departments concerned should repeatedly carry out multifaceted simulation tests, including chemical explosive detonation tests, material and strength tests, environmental conditions tests, control, ignition and safety tests, and so on, all of which are indispensable for achieving a high degree of reliability and safety of nuclear weapons.

The necessary nuclear tests, whether they are extensive calculations on electronic computers or corresponding simulations, cannot be 100 per cent consistent with the reality of a nuclear weapons programme.

……

Zhao Weidong told Ji Lingjun in detail what he had learned about all the relevant technologies in later generations, and she also recorded all the contents in detail while listening carefully.

After finishing the recording, Ji Lingjun saw that she had unconsciously put the thick record book in her hand, and she had recorded almost one, and when she saw the dense records in her hand, she knew the great value of the technology in this record book.

She thought that nuclear technology is the top secret of the major countries, and it is high-tech, extremely professional, he is only a freshman student now, could it be that his younger brother is an expert in nuclear technology, otherwise how can he have such a high level of professional knowledge.

Moreover, there is not much information disclosed about these technologies, some are just some scientific papers, some news reports, and there is no specific and operable content at all.

In addition, there is an analysis of the pros and cons of the development of nuclear technology, which is appropriate, and has put forward a very practical plan for the development of nuclear weapons, which is simply not possible in the general environment of strict blockade of nuclear weapons technology.

I don't know how my brother did it? No one knows the magic of his younger brother better than himself, but the longer he has been in contact with him, the more unfathomable he feels, of course, from a large number of scientific and technological books from various countries in his office and at home, a certain clue can also be seen.

She was glad to have such an outstanding younger brother, she could never have imagined that someone would have such an unparalleled talent, maybe this is a genius.

This can be achieved by the control of the critical mass or critical dimensions, in principle, the simplest atomic bomb uses the so-called gun structure, two pieces of uranium that are both smaller than the critical mass, separated by a certain distance, do not cause an explosion, and when they are combined, they are greater than the critical mass and an explosion occurs immediately.

But if they are put together slowly, then soon after the chain reaction begins, the energy generated is enough to blow them away, and to stop the chain reaction, the explosive power of the atomic bomb and the utilization rate of the nuclear charge are very small, which is somewhat similar to the situation in the case of a supercritical accident explosion of a reactor, so the key problem is to make it possible for them to come together very quickly.

This makes it possible to place one part of the uranium at one end and the other part inside the "barrel", which, with the help of high explosives, brings them together completely and very quickly, creating supercriticality and producing a highly efficient explosion.

To reduce neutron loss, the nuclear charge has a neutron reflector layer on the outside; To delay the dispersion of the nuclear charge, the atomic bomb had a solid casing.

In August 1945, the atomic bomb (codenamed "Little Boy") dropped by the United States on Hiroshima, Japan, was a gun-like structure, weighing about 4,100 kilograms, with a diameter of about 71 centimeters and a length of about 305 centimeters.

The nuclear charge is uranium-235, the explosive power is about 14,000 tons of TNT equivalent, in the gun structure, each nuclear charge can not be too large, at most it can only be close to the critical mass, and can never be equal to or exceed the critical mass.

Therefore, when the two nuclear charges are combined, the total mass can only be nearly twice as much as the critical mass at most. This limited the explosive power of the atomic bomb.

In addition, in the gun structure, although the two nuclear charges are closed at high speed, the time that elapses during the closing process is still too long, so that the neutrons released by spontaneous fission cause an explosion before the two nuclear charges are fully combined.

This "premature ignition" causes inefficient explosion, so that the utilization rate of nuclear charge is very low, one kilogram of uranium-235 (or plutonium-239) is all fission, about 18,000 tons of TNT equivalent energy can be released, and the nuclear charge of an atomic bomb is generally 15~25 kilograms of uranium-235 (or 6~8 kilograms of plutonium-239), so that the utilization rate of the nuclear charge of the "little boy" is less than 5%.

The density of uranium at normal pressure is about 19 g/cm. At high pressure, uranium can be compressed to a higher density. Studies have shown that for a given fission material, the higher the density, the smaller the critical mass. According to this characteristic, in parallel with the development of the gun structure, an implosion type was developed.

In the gun structure, the atomic bomb achieves supercriticality by suddenly increasing the amount of fissile material at normal density, while the implosion structure atomic bomb achieves supercriticality by increasing the density by suddenly increasing the pressure.

In the implosion structure, a high explosive with a high explosion velocity is made into a spherical device, and a nuclear charge less than a critical mass is made into a small ball, which is placed in the explosive. Through the synchronous ignition of the electric detonator, the explosives are detonated at each point at the same time, generating a powerful centripetal focused compression wave (also known as an implosion wave), so that the peripheral nuclear charge closes to the center at the same time, so that its density is greatly increased, that is, it is greatly supercritical.

Then use a controllable neutron source and wait until the compression wave effect is at its maximum, and then "ignite" it. This results in a self-sustaining chain reaction, resulting in an extremely violent explosion.

The advantage of implosion structure over gun structure is that the compression wave effect takes much less time than the time it takes for the gun structure to close, so the probability of "premature ignition" is greatly reduced. In this way, the implosion structure can use fissile materials with a high probability of spontaneous fission, such as plutonium-239, as a nuclear charge; At the same time, the utilization efficiency is greatly increased.

The atomic bomb dropped by the United States on Nagasaki, Japan (codenamed "Fat Man") used an implosion structure and used plutonium-239 as a nuclear charge. The bullet weighs about 4,500 kilograms, the diameter of the projectile is about 152 centimeters at the thickest point, the length of the projectile is about 320 centimeters, and the explosive power is estimated to be 20,000 tons of TNT equivalent.

The further development of the atomic bomb was the hydrogen bomb, or thermonuclear weapon. Hydrogen bombs use the enormous amounts of energy emitted by certain light nuclear fusion reactions. Its charge can be deuterium and tritium, as well as lithium deuteride-6, and these substances are called thermonuclear materials.

In terms of material per unit weight, the nuclear fusion reaction emits more energy than the fission reaction, and there is no so-called critical mass limit, so the explosive power of the hydrogen bomb is greater, generally hundreds to thousands of times greater than that of the atomic bomb.

However, thermonuclear reactions can only be carried out at extremely high temperatures (tens of millions of degrees), and such high temperatures can only be produced when an atomic bomb explodes, so the hydrogen bomb must use the atomic bomb as a "detonator" to ignite the thermonuclear material.

When a hydrogen bomb explodes, it releases a large number of high-energy neutrons that can cause uranium-238 to fission. Therefore, a layer of uranium-238 on the outside of a general hydrogen bomb can greatly increase the explosion power. The explosion of this kind of nuclear bomb goes through three processes: fission, fusion, and fission, so it is called a "three-phase bomb." It is characterized by low cost, high power, and high radioactive contamination.

There is also a new type of nuclear bomb, the so-called neutron bomb, the neutron bomb may actually be a small hydrogen bomb, but the fission component in this small hydrogen bomb is very small, and the fusion component is very large, so the effect of shock wave and nuclear radiation is very weak, but the neutron flow is extremely strong.

It relies on a strong stream of neutrons to kill and is said to be able to "kill without destroying things", and the atomic bomb can be made from uranium or plutonium, but plutonium is made from uranium.

The hydrogen bomb had to be introduced with an atomic bomb. Therefore, in the final analysis, the manufacture of nuclear weapons, thermonuclear weapons, cannot be done without uranium.

Thus, in the past, today, and for a long time to come, the heaviest natural elements are important, first of all, in military necessity.

To manufacture an atomic bomb, it is necessary not only to solve a series of scientific and technological problems in the development of weapons, but also to be able to produce the necessary nuclear charges uranium-235 and plutonium-239, and the abundance of uranium-235, the isotope uranium-235 in natural uranium, is only 0.72 percent, and it must be increased to more than 90 percent according to the design requirements of the atomic bomb.

In addition to the production of uranium-235, plutonium-239, and other nuclear materials, the development of the nuclear warhead itself must be coordinated with the development procedures of the entire nuclear weapons system.

The specific development process is roughly arranged as follows:

Start with the planning phase; After the preliminary study or feasibility study of key technical topics and components, several design schemes including weight, size, form, power, nuclear materials, nuclear test requirements, development period, and funding are formed.

Then, after demonstration, comparison and evaluation, the design scheme is selected, and the tactical and technical indicators are determined. Then, the model study design and various simulation tests are carried out.

Process test and trial production, through nuclear test to test the rationality of the design, and finally to achieve the design finalization, process finalization and approved production.

To carry out this work, it is necessary to secretly organize the recruitment of specialized scientific and technological teams and to equip them with the necessary test sites, including nuclear test sites.

After the weapons are delivered to the troops, the R&D and production departments also provide services such as maintenance, repair, and replacement of parts, make necessary improvements according to the feedback information, and be responsible for their decommissioning, processing, and renewal.

In order to do a good job in the design of a nuclear warhead, it is necessary to have an in-depth understanding of its reaction process, to understand the conditions and various physical parameters that it must have, and to grasp the internal relations and laws of change of many factors.

To this end, it is necessary to conduct research on a series of scientific and technological issues in multiple disciplines, such as nuclear physics, neutron physics, high-temperature and high-pressure condensed matter physics, supersonic fluid mechanics, detonation, computational mathematics, and materials science.

Zhao Weidong also proposed that in the process of development, special attention should be paid to the following links:

It is necessary to arrange for the New York Computer Company in the United States to immediately begin to develop a fast, large-capacity electronic computer for the calculation and simulation of nuclear reactions to carry out theoretical research and calculation of the reaction process, and such calculations should be as close as possible to the actual situation, so as to find the optimal scheme from a variety of assumptions or design schemes, so as to save costs and reduce the number of nuclear tests.

Of course, minimizing the number of nuclear tests is not just about saving money, but more importantly, because the world's major powers are eyeing up and trying to avoid unnecessary conflicts, and they are certainly not happy to have another country with nuclear forces.

In accordance with the requirements of the program or indicators, the departments concerned should repeatedly carry out multifaceted simulation tests, including chemical explosive detonation tests, material and strength tests, environmental conditions tests, control, ignition and safety tests, and so on, all of which are indispensable for achieving a high degree of reliability and safety of nuclear weapons.

The necessary nuclear tests, whether they are extensive calculations on electronic computers or corresponding simulations, cannot be 100 per cent consistent with the reality of a nuclear weapons programme.

……

Zhao Weidong told Ji Lingjun in detail what he had learned about all the relevant technologies in later generations, and she also recorded all the contents in detail while listening carefully.

After finishing the recording, Ji Lingjun saw that she had unconsciously put the thick record book in her hand, and she had recorded almost one, and when she saw the dense records in her hand, she knew the great value of the technology in this record book.

She thought that nuclear technology is the top secret of the major countries, and it is high-tech, extremely professional, he is only a freshman student now, could it be that his younger brother is an expert in nuclear technology, otherwise how can he have such a high level of professional knowledge.

Moreover, there is not much information disclosed about these technologies, some are just some scientific papers, some news reports, and there is no specific and operable content at all.

In addition, there is an analysis of the pros and cons of the development of nuclear technology, which is appropriate, and has put forward a very practical plan for the development of nuclear weapons, which is simply not possible in the general environment of strict blockade of nuclear weapons technology.

I don't know how my brother did it? No one knows the magic of his younger brother better than himself, but the longer he has been in contact with him, the more unfathomable he feels, of course, from a large number of scientific and technological books from various countries in his office and at home, a certain clue can also be seen.

She was glad to have such an outstanding younger brother, she could never have imagined that someone would have such an unparalleled talent, maybe this is a genius.

This book was first published from 17K, the first time to see the genuine content!

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