in the 1980s, the United States and the Soviet Union were in the cold war period of nuclear arms race. Although the United States conducted underground nuclear tests secretly, the Soviet Union would immediately announce to the world that the United States conducted underground nuclear tests. So how did the Soviet Union grasp this information? It turns out that the blast wave generated by nuclear explosion can reach the interior of the earth, and others can know it by capturing the seismic wave. In addition, a new crater in the Nevada desert can also be found through the reconnaissance satellite, which must correctly infer that a new underground nuclear test has been carried out.

: “Modern Express”, A32 edition, December 15, 2010, author: Wu Shuo, original title: “decrypting the underground nuclear test site of the United States”,

in the middle of the 20th century, the two superpowers of the United States and the Soviet Union frequently conducted underground nuclear tests in order to compete for nuclear hegemony. Today, all this has become a thing of the past, People still want to know what will happen underground at the moment of underground nuclear explosion. This paper will uncover this secret through the underground nuclear test in Nevada, USA. Nevada underground nuclear test site (NTS) is about 150 kilometers northwest of Las Vegas, the capital of Nevada. From 1951 to 1963, it was the US atmospheric core test site. However, after the treaty banning all nuclear tests except underground was signed between the United States, Britain and the Soviet Union in 1963, it became the only underground nuclear test site in the United States.

how the nuclear explosion is carried out

first select the location of each underground nuclear test, and drill holes vertically with a rock drill weighing up to 200 tons. The hole size is designed to be 1-4 meters and the depth is 100-1500 meters according to the test scale. Then, a tunnel hundreds of meters long is excavated horizontally from the explosion point at the bottom. A container is placed at the end of the tunnel, in which an instrument for measuring nuclear explosion parameters is placed.

then, another slender steel container containing test explosives was hoisted to the bottom of the vertical tunnel. There are two kinds of subcritical fissile materials in the steel container. During the test, they will be combined to reach the critical point to form a nuclear explosion. Then, a thick insulated wire is led from the top of the steel container to the control room.

once the circuit is connected, a nuclear explosion will occur.

at this time, the dark underground glitters with dazzling light from time to time. The energy is released at once through nuclear fission reaction and nuclear fusion reaction. At the same time, it throws out strong gamma rays, X-rays and emits high-density neutrons at the speed of sub light. After one millionth of a second of the reaction, the central temperature rises to tens of millions of degrees Celsius, and the pressure reaches thousands of times the atmospheric pressure on the ground.

the steel container for nuclear explosives and the rocks around it are vaporized in the blink of an eye and expand to the rock plate with amazing pressure in a few tens of seconds. When the light disappeared, an underground hole with a diameter of more than ten meters was dug under the explosion center. The rock plate boils and evaporates, slowly flowing to the bottom of the cavity.

on the other hand, under the impact of explosion, countless cracks appear in the depth of rock plate, and steam and radioactive gas are stuffed into the cracks under huge pressure. Once the upward seismic wave reaches the surface, the earth will jump up into the air in an instant. Then, as the pressure fades, a crater will be formed in the depression of the ground.

one minute after the nuclear explosion, the magma accumulated at the bottom of the underground cavity will form a magma pool, and as the surrounding rock plate continues to absorb the heat generated by the explosion, the temperature in the cavity will eventually cool down.

why did the Soviet Union know the secret of Nevada

these are the “moment” when the underground nuclear test was carried out in the Nevada desert at the rate of more than ten times a year.

but the scale of each underground nuclear test is different. When converted into high-performance TNT explosive, there are both 1000 tons and more than 100000 tons. Usually, after the underground test, there are two situations in the vertical tunnel: one is that the rock in the tunnel stops halfway, and the other is that the rock falls completely and there is a crater on the surface. If the power of the nuclear explosion is too great, or the depth of the vertically excavated tunnel is not enough, or the stratum is not a solid rock plate, soon after the explosion, the sand and rock backfilled in the tunnel will collapse around the tunnel together, and the soil avalanche will fall into the cavity, which will sag part of the surface, and sometimes a huge crater with a diameter of 200 meters and a depth of 20 meters will appear. The 200 craters scattered on the Nevada test site are all produced in this way.

in the 1980s, the United States and the Soviet Union were in the cold war period of nuclear arms race. Although the United States conducted underground nuclear tests secretly, the Soviet Union would immediately announce to the world that the United States conducted underground nuclear tests. So how did the Soviet Union grasp this information? It turns out that the blast wave generated by nuclear explosion can reach the interior of the earth, and others can know it by capturing the seismic wave. In addition, a new crater in the Nevada desert can also be found through the reconnaissance satellite, which must correctly infer that a new underground nuclear test has been carried out.

Nevada underground nuclear test methods were still used in the late 1990s, which can be roughly divided into two types: the first is the development test of explosion equivalent (explosion power) causing explosion at the bottom of vertical tunnel as described above, and the second is the test for nuclear impact investigation. Usually, such tests are carried out in radial horizontal tunnels excavated underground (with a total length of more than 10 kilometers).

in the late 1990s, although computer simulation was used to develop new nuclear bombs, it was impossible to confirm whether they reached the design performance without actual explosion test, so they still had to be tested in Nevada. The test of

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in the horizontal tunnel aims to study the impact it will have on nuclear missiles, man-made satellites or communication facilities through the nuclear explosion caused by the nearest distance. becauseIn the case of nuclear attack by the enemy, these devices are easy to be damaged by radiation or electromagnetic pulse and will lose the counterattack ability, so it is very important to develop technologies that can survive even if they are attacked by nuclear attack. The development of these technologies is inseparable from the investigation and test in the horizontal tunnel.

incidentally, the underground nuclear test seems to fix the radioactivity on the rock plate and avoid the dispersion of radioactive materials into the atmosphere, but it can never guarantee that it will not leak to the ground. In fact, if the tunnel depth is not enough, it will cause radioactive gas to flow to the ground through the gap of backfill rock. For example, an underground nuclear test in the United States in 1970 brought radioactive gases to Canada. In 1971, radioactive substances leaked from the underground nuclear test of the Soviet Union were also detected in Sweden. Of course, people have rarely heard of underground nuclear tests today. I hope all this has become history.