The damaging factors of a nuclear explosion
The power of atomic bombs can differ by an order of magnitude, but in general they have the same damaging factors. The first is temperature. In a nuclear explosion, a fireball is formed at a temperature of thousands and hundreds of thousands of degrees. The radius of the fireball does not exceed a hundred or two meters, but at a certain distance from it, people can get burned with a flash of light that lasts no longer than a few seconds.
After the flash comes the shock wave. It looks like the wave of an ordinary explosion, but it is much stronger and spreads much farther. The unique factor in a nuclear explosion is radiation. The penetrating radiation is similar to a flash, but consists of gamma radiation or a stream of neutrons, not light. The effect time of penetrating radiation is 15-20 seconds for objects on the earth’s surface. Then radiation pollution occurs and as a result the surrounding area, dust and precipitation thrown into the air begin to shine. The strength of each of the factors in bombs of different designs is different. For example, there are specially designed hydrogen bombs that practically do not harm the area. Some time in the 20th century, the idea of a neutron bomb with a relatively weak flash and shock wave, but with a strong radiation flux, was popular.
all-consuming fire
It is impossible to survive inside the fireball due to the enormous pressure and temperature. No traces remained after the explosion from the towers where the nuclear charges were placed during the experiments. But there are exceptions here too. In 1955, during a series of American Teapot tests (14 nuclear test explosions in Nevada), researchers set up towers at different distances from the bomb. Balls and spheres of various materials (steel, aluminum, as well as ceramics and graphite, from which the inserts were made) were fixed on the towers.
Cannons near the center were not found, but objects within 25 meters of the bomb survived. The explosion hurled them 120 meters away, and they would have thrown them much further if they had not crashed one meter into the ground. The outer layer of the material eroded (evaporated), but the balls themselves, like the rollers, were quite recognizable. Later, the results of these observations formed the basis of the nuclear “explosive” (“Orion project”) project, a spacecraft that would detonate bombs on a special plate behind it, thereby accelerating.
Almost all atomic bombs explode at least a few hundred meters to cover as much area as possible. As a result, the real danger is glare, as the fireball will never reach the ground. It can set objects on fire, causing severe burns to people, and can also cause blindness tens of kilometers from the epicenter. It’s also relatively easy to defend against flash because it can’t pierce opaque material. It does not pass through the walls, and even a textile curtain can significantly weaken its effect. The fabric will likely catch fire but will last long enough to cast a shadow.
Flash exposure is highly dependent on the color of the subject. During the experiments, the white-painted wooden houses were hardly affected by the fire, and the black ones burned like torches. This is why some aircraft designed to carry out nuclear strikes (and get rid of nuclear anti-aircraft missiles) are painted white or silver.
shock wave danger
It is much more difficult to defend against a shockwave, and the main damage is usually associated with it. With an explosion force of tens of kilotons, the radius of the zone of severe destruction is about two kilometers, medium – up to five. The wave destroys buildings and causes damage to the human body; It mainly affects body parts to which tissues of different densities are attached, as well as the air-containing lungs and abdominal cavity. Unlike light, the shockwave can bend around terrain and obstacles, but loses power with each turn.
It is this feature that can be used for protection. Ideally, during a nuclear explosion, it is necessary to hide in a reinforced concrete building with thick walls and few windows where the shock wave penetrates. But in a modern city, such buildings that look suspiciously like bunkers are avoided. Therefore, a basement with almost no windows is an alternative. A well-built basement remains intact, despite the almost complete destruction of the above-ground part of the building, as numerous nuclear tests have shown.
Any deepening, including shallow metro stations, underground passages, will help protect yourself. Even a concrete railing can help: at least it will protect against flying objects that are shattered by the explosion.
In general, the basement of a country house can also be a suitable shelter from the blast wave if it has concrete floors. On the contrary, it should not be confused with the “underground” of wooden houses where people can get overwhelmed. In addition, recent mathematical models have shown that you should not be in tight spaces in the shelter. The blast wave speeds up when entering a narrow corridor, so the ideal position is to stand in the corner of a large room.
Tests at the Soviet Semipalatinsk test site have shown that it is possible to survive a very close explosion by hiding in a shallow metro station (although precise data on this experiment have not been published).
In Hiroshima, 20-year-old Akiko Takakura survived with minor injuries despite being 300 meters from the epicenter. He escaped because he was in the lobby of the reinforced concrete bank building.
In 1953, during tests, a 10 kiloton atomic bomb was detonated 450 meters from the wounded British Centurion tank. It was badly damaged and would most likely have been destroyed by the shockwave if there had been a crew inside. But after the tests the tank was still in motion and after repairs it was used in the Vietnam War.
invisible enemy
The atmosphere quickly absorbs a burst of radiation from a conventional atomic bomb, so its effect is negligible. An exception is neutron bombs, where 80% of the energy is released in the form of fast neutrons that damage living tissue. Today, neutron bombs are almost abandoned due to their general uselessness, and also because military equipment can be easily protected from them with an anti-neutron lining.
However, in an explosion on land, any nuclear weapon contaminates the area with radioactive material. This factor can certainly be called the worst and most dangerous. If the glow and explosion lasts for a few seconds and is visible to the naked eye, radiation pollution is invisible and will persist for years, if not centuries.
The substance of the fireball becomes radioactive under the influence of neutrons, and after a while it falls back to earth, including in rain. The design of classical civil defense shelters, the main feature of which is maximum isolation from the environment, was created precisely to protect against radioactive fallout.
The purpose-built shelter is equipped with thick walls, airtight doors and a filtered ventilation system to protect against external radiation. Also, perfect firmness is not required, as the bulk of the radioactive fallout is similar to sand. Therefore, during the Cold War, Westerners sometimes equipped a shelter in the basement of a country house. Example of do-it-yourself drawings of these shelters published but in general the processing of the basement involved thickening the walls where they protruded from the ground. It is also necessary to close windows and ventilation openings.
It is much more important to have a supply of food and water in the shelter for at least two weeks to avoid going into the infected area. If you have to go outside, you cannot touch outdoor objects, pick fruit or mushrooms, or drink water from puddles where raindrops can come.
Civil defense guidelines recommend wearing respirators, tight clothing, rubber shoes and gloves when leaving. All this must be carefully removed and put in a bag before returning to the shelter. It is believed that it will take at least two weeks to stay in the shelters until the background radiation level subsides, but this can only be known for certain from civil defense alerts. Dosimeters and radiometers can help measure background radiation, but without special knowledge the user will not be able to tell if the area is truly safe.
Therefore, to survive a nuclear explosion, it is not necessary to have a truly equipped bunker, such as the American missile defense command center on Cheyenne Mountain or its Russian counterparts. On the contrary, it would be wise to stay away from such places as much as possible in the event of a nuclear war. The location of such bunkers is well known, and a large ship is a large torpedo.