On the types of nuclear weapons
The explosion of the first Soviet nuclear bomb RDS-1, 1949. Photo by Wikimedia Commons
Since the mid-forties, nuclear and thermonuclear weapon - systems of special power, using the reactions of decay or fusion of the atomic nucleus. Over the past decades, scientists and engineers have proposed a number of varieties of such weapons with various principles of operation, design features and capabilities. Some of these proposals have successfully passed through the stage of research and practical testing, confirmed their potential and entered service.
Decay energy
The first to propose, theoretically substantiate, manufacture and test nuclear or atomic weapons. It was this class that included the American products Gadget, Little Boy and Fat Man, the Soviet RDS-1, etc. For some time, it formed the basis of nuclear arsenals - until the appearance of thermonuclear systems, which have a number of important differences.
Such weapons use the principle of an avalanche-like chain reaction of the decay of an atomic nucleus with the release of a large amount of energy. Blocks of uranium-235 or plutonium-239 with a high degree of enrichment are used as a single-stage charge in such products. Studies of other isotopes were carried out, but they did not receive practical continuation. Charges can have different configurations and be used in devices of different circuits.
A chain reaction is started by transferring the fissile material to a critical state - by connecting several blocks or by compressing a single charge. After that, the decay of nuclei into lighter elements begins with the release of various particles, incl. neutrons that "break" the next nuclei, which leads to the continuation of the reaction.
Ivy Mike test - the first US thermonuclear explosion, 1952. Photo by the US Department of Defense
"Conventional" atomic weapons are notable for their limited effectiveness: only tens of percent of uranium/plutonium enter into the reaction. In addition, there is a possibility of the so-called. pops (fizzle) - reactions of an insufficient amount of a substance with insufficient power. However, even under optimal conditions, a nuclear charge with one stage has a limited potential and allows you to get a power of no more than hundreds of kilotons of TNT.
The efficiency of a nuclear charge can be increased by the so-called. amplification or boosting. The amplifying charge is distinguished by the presence of a small amount of a deuterium-lithium mixture. Under the influence of the main charge in such a mixture, a thermonuclear fusion reaction begins. In this case, an additional number of neutrons is released, which act on the fissile material. Boosting allows you to maximize the energy output with minimal complication of the design of the device.
Synthesis reaction
In 1952 and 1953 The USA and the USSR conducted the first tests of their thermonuclear charges. Such weapons used a new scheme that made it possible to increase their power to tens of megatons. For obvious reasons, thermonuclear warheads quickly passed the testing stage and entered service. In the future, thermonuclear weapons came to the forefront and almost completely replaced the products of the previous generation.
AN602 bomb model. Photo by Wikimedia Commons
Thermonuclear ammunition is noticeably different from nuclear weapons. It is two-stage and works according to the two-phase principle. The first stage is a "normal" atomic charge, and the second includes deuterium and lithium-6 deuteride, used as a so-called. thermonuclear fuel. Also in the design of the product there are additional devices and components for various purposes.
Under the influence of a nuclear reaction of the first stage, thermonuclear fusion will begin in the second. Helium is formed with the release of neutrons and a large amount of energy. Depending on the number of so-called. thermonuclear fuel and other parameters, the power of two reactions can reach 20-25 Mt.
The use of more complex designs allows you to further increase the power of the explosion. Thus, in 1961, the Soviet AN602 free-falling thermonuclear bomb with an estimated yield of 50 Mt and an actual power of 58 Mt was tested. At the same time, the original project made it possible to obtain an energy yield exceeding 100 Mt.
In the AN602 product, a three-stage device scheme was implemented. The first two stages were two-phase thermonuclear devices with a power of 750 kt each. They were supposed to start the reaction in the third stage, including thermonuclear fuel and a uranium charge. Simultaneous decomposition and synthesis reactions made it possible to use the available materials to the fullest and obtain maximum power. At the same time, for security reasons, the experimental bomb did not receive uranium elements.
Warheads W78 for American missiles. Photo by the US Department of Defense
However, AN602 remained an experimental product. We went into the series and entered service with warheads of lower power. At the cost of a reasonable power limitation, it was possible to obtain the necessary efficiency with acceptable dimensions and weight.
Increased neutron yield
A variety of thermonuclear weapons is neutron. This concept provides for the creation of a special charge that produces a powerful stream of fast neutrons. These particles are characterized by high penetrating power, which ensures effective destruction of manpower and other targets, incl. behind various barriers. In addition, the neutron charge creates induced radioactivity in the surrounding objects.
The neutron charge is a variant of the two-phase device with a special second-stage charge that gives an increased neutron yield. In addition, the charge requires a shell that does not trap such particles. A properly designed device releases up to 75-80 percent. energy in the form of neutrons. In this case, fast particles fully compensate for losses in other damaging factors.
However, neutron weapons face some limitations. Thus, during an air blast, the neutron flux is scattered and absorbed by the atmosphere. This reduces the range of destruction of manpower to 1-1,5 km, regardless of the presence of protection. As a result, the neutron charge does not have significant advantages over weapons of other classes.
The head of the ICBM with modern blocks W87. Photo by the US Department of Energy
At the same time, neutron warheads have found application in anti-missile and anti-space defense projects. At high altitudes, in a rarefied atmosphere or outside it, neutrons do not encounter interference and can fly long distances - hitting manpower and equipment, or causing nuclear explosions.
Theoretical Threat
Back in the early fifties, American physicists proposed the idea of a cobalt bomb. This concept provided for the creation of a special modification of a thermonuclear charge capable of creating stable radiation contamination of the area. Just a few of these high-power products, regardless of their location, could destroy all life on the planet in a short time. As a result, the cobalt bomb was also called the Doomsday Device.
Such a "Machine" in its design repeats a two-stage thermonuclear charge, but cobalt-59 is added in the second stage. Upon explosion, this isotope receives a neutron and turns into radioactive cobalt-60 with a half-life of 5,2 years; a number of other hazardous elements are also formed.
The particular danger of the cobalt bomb would have made it an effective deterrent. An attempt to attack her master could result in a full-scale radiation disaster. However, these ideas did not receive support, and the Doomsday Device remained an exclusively theoretical development. In addition, such weapons have firmly entered popular culture.
Launch of the R-36M rocket. On board the rocket can be from 10 warheads of 10 Mt to one of 20 Mt. Photo by the Ministry of Defense of the Russian Federation
In the nineties, also in the USA, the so-called. hafnium bomb. It was argued that the hafnium-178m2 isomer under external influence can begin to decay with the release of gamma radiation. According to calculations, such a reaction made it possible to obtain energies 100 thousand times greater than the equivalent amount of explosive, although 100 times less than nuclear decay.
In 1998, a group of scientists reported that they had managed to provoke the decay of hafnium-178m2, but the energy yield was minimal. It was assumed that further studies would help to find the optimal regimes and start the decay. However, no one has been able to replicate even the initial experience, let alone any progress. Apparently, there was some kind of mistake or deliberate hoax.
nuclear progress
Since its inception, nuclear weapons have come a long way. Various schemes with certain features and advantages were proposed and implemented. Based on them, real ammunition for tactical and strategic purposes, as well as their means of delivery, were developed. A variety of tactics and strategies for use and application were created and implemented.
It should be noted that not all ideas and solutions have reached practical implementation. Some proposals were rejected after theoretical analysis or as a result of further elaboration. As a result, only the most successful and efficient designs reached production and operation. And over the past few decades, they have ensured the security of the creator states.
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