An opinion by Michel Wautelet, Professor Emeritus of UMons
Since the end of the Cold War in the 1990s, nuclear weapons have become, for military experts, more of a theoretical concept than a reality. Which government would be crazy enough to actually use nuclear weapons? This would lead, in retaliation, to their own destruction. No one seems to have asked what Hitler would have done, for example, if he had had nuclear weapons at the time of the German defeat in 1945. But no! There are no crazy rulers today.
Since Putin’s recent threats, we’ve been wondering about the real effects of tactical battlefield nuclear weapons. Which, being “tactical”, would only have limited effects. Except that current tactical nuclear weapons would have powers comparable to those launched in Hiroshima and Nagasaki in 1945.
What are the effects of tactical nuclear weapons?
Let us first remember that the unit of energy released (erroneously called the “power” of the weapon) is the kiloton (kt), corresponding to the energy released per kilo (thousand tons) of classical explosive (genus TNT ). The Hiroshima bomb had an estimated power of about 13 kt; the one in Nagasaki, about 22 kt. Tactical nuclear weapons have powers between 1 kt and a few hundred kt. Next, consider the case of a “medium” tactical nuclear weapon with a power of about 20 kt.
There are four main effects of nuclear explosions: immediate nuclear radiation, heat flash, shock wave, and radioactive fall. To which we can add the electromagnetic pulse. Note that the distances given below are orders of magnitude. The actual value depends on many factors such as the climate, the geography of the site, and even how the explosion occurs (there are also defective nuclear bombs).
The electromagnetic pulse is due, in the first moments of the explosion, to the ionization of the surrounding atmosphere and the separation of positive and negative charges due to the Earth’s magnetic field. This translates into a very intense electromagnetic pulse, which can damage all electrical and electronic equipment within a considerable radius.
Immediate nuclear radiation
Immediate nuclear radiation results from the nuclear reactions that take place during the explosion and just after, in the vicinity of the weapon that explodes. In the same way that the effects of the thermal flash and the shock wave lead to instant death in the same areas; talking about it makes little sense.
In a nuclear weapon, the nuclear reaction is a very fast chain reaction. All energy is released in a split second. The initial temperature of the material at the site of the explosion reaches several million degrees Celsius. A “fireball” is formed.
A split second after the explosion, the fireball emits a flash, called a “thermal sheet.” Its effects are very destructive to anything in the direct line of the explosion. The “thermal flag” causes severe burns, fires.
For our tactical bomb, the unfortunate 2.5 km from the explosion would have third-degree burns. Clearly, the consequences for humans, animals, vegetation, housing, and so on. they are considerable.
The shock wave
After the heat flash comes the shock wave. Its effects range from the destruction of houses to the rupture of eardrums. For the tactical bomb, the windows break within a radius of about 5 km, causing many injuries. The eardrums were within a radius of 2 km, making all people deaf for life. The houses are destroyed up to 2 km away. Etc.
If the explosion takes place on the ground, the shock wave propagates to the ground and causes effects comparable to earthquakes. A 20 kt explosion releases as much energy as a magnitude 6 earthquake on the Richter scale. It causes significant damage within a radius of several tens of km.
Immediately after the explosion, under the fireball, vertical winds develop from the bottom up and bring it into the atmosphere. It is the nuclear mushroom that carries with it a significant amount of radioactive material. This radioactivity is carried more or less far, depending on the weather (wind speed and direction) and the altitude reached by the nuclear fungus.
For our tactical bomb, the probability of death from radioactive fallout is 50% at a distance of about 2 km from the explosion. In case of wind, the distance to the explosion is much greater in the wind direction. Of course, the real danger extends over a much larger area, for years. We recall the long-term effects of the victims of Hiroshima and Nagasaki.
Some radioactive isotopes (such as 131I) are emitted in amounts comparable to those emitted during the Chernobyl power plant explosion. Remember that this isotope has spread to our regions. The effects of radioactivity on the use of a single tactical nuclear weapon in Ukraine could extend to our country. The use of several would have more devastating effects.
Today’s generations have not known Hiroshima and Nagasaki. For many, nuclear weapons are science fiction devices. The reality is very different. The smallest nuclear weapon is much more powerful than the most powerful conventional weapon. Let’s never forget that!