Many of us associate the explosion of an atomic bomb with total annihilation, the decline of civilization, and the general end of the world. We imagine that a nuclear strike will wipe half of Poland off the map. We feel helpless - since entire voivodeships will cease to exist in a matter of seconds, what is the point of thinking about preparing for such an eventuality? In a sense, this is understandable - it is easier to give up preparation and live blissfully ignorant than to worry and try to protect yourself from something that has no defense. After all, if an atomic bomb falls on us, nothing will save us.
Well, that's not true. The effects of an atomic bomb in our consciousness are definitely exaggerated. In fact, the damage a ballistic missile can do is not that powerful, and the real threat of nuclear charges lies in something other than direct destruction.
What does an atomic bomb explode?
A nuclear charge explosion causes seven successive phenomena. The first four occur almost simultaneously.
1. A flash of light - this is the first thing you see - a blinding flash of light that can last for a few seconds. It carries visible, ultraviolet, and thermal radiation (about 1% of all thermal radiation emitted by a nuclear charge). ABSOLUTELY NEVER LOOK AT THE Flare, as this can seriously damage the retina, leading to temporary or permanent blindness.
2. Heatwave - composed of visible and infrared radiation, it contains 99% of the total thermal radiation emitted by an explosion. The wave causes comprehensive destruction, fires, and mass death of living organisms. Moreover, the heat wave has the greatest damage range.
3. Ionizing radiation - not only gamma radiation but also fast neutrons that react with matter and produce secondary radiation.
4. Electromagnetic pulse (EMP) - an electromagnetic wave induced in power networks and electronic devices, permanently damaging them. As a result of an explosion of a nuclear charge, three electromagnetic pulses are generated. The first two are immediate and short-lived, while the third travel much slower and lasts up to several minutes, reminiscent of a magnetic storm. The range depends on the type of nuclear charge used but should be counted in tens of kilometers.
5. Fireball - factor with the smallest range and enormous firepower. In the event of a ground explosion, it creates a crater
6. Shock wave - a rapid increase in air pressure. Near the epicenter, the shockwave is extremely destructive, but its strength decreases relatively quickly, making the destructive range much smaller than that of the heat wave.
7. Radioactive fallout - fragments of earth and everything on it - buildings, roads, and vehicles are sucked into the center of the fireball, where they melt with the products of nuclear fission, creating a characteristic atomic mushroom. This mixture then falls to the ground in the form of smaller or larger particles. The largest fragments form the local rainfall that will occupy the area near the epicenter. Some of the particles will blow away with the wind, contaminating a huge part of the terrain, and the tiniest fraction will get into the stratosphere, sometimes falling thousands of kilometers from the epicenter.
Suppose the nuclear charge will have a power of 300 kilotons. Is that a lot? Yes. By comparison, the nuclear load dropped on Hiroshima had a power of about 15 kilotons or about twenty times less. Of course, the United States, Russia, and China have many times larger payloads, Multiple independently targetable reentry vehicles (MIRV), or neutron bombs, but most of the existing nuclear warheads in the world have more or less this power.
Description of damage, starting with the smallest in terms of surface:
1. Yellow zone: radius 0.78 km - this is how big the fireball will literally consume the center. Nobody in this part will have any chance of survival.
2. Red zone: radius 1.46 km - extremely strong shock wave that destroys almost all ground infrastructure. The chances of survival are zero.
3. Green zone: radius of 2.14 km - radiation range with a dose of 5 sieverts (mortality 50% of the population).
4. Blue zone: radius 3.06 km - shock wave destroying most residential buildings, but the chances of survival are greater than zero and depend on the shelter (high survival in shelters and underground rooms).
5. Orange zone: 6.33 km radius - heat wave causing deep 3rd degree burns. Potentially fatal, the amount of damage depends on where you are and what cover is used (thick walls, pits, shelters, and basements).
6. Bright orange zone: 8.32 km radius - heat wave causing 2nd-degree burns, mostly non-life threatening.
Even assuming that the blue zone is a 100% mortality area, the effects are much smaller than the evaporation of half of the province, which we often imagine. In the above scenario, some residents of Żoliborz and Mokotów would have a chance to survive, provided they stay in buildings strong enough not to collapse.
Even with a nuclear charge of 1000 kilotons (more than sixty times the size of Hiroshima) detonated at 2.5 kilometers to increase the blast wave, the 100% fatality area will have a radius of 6.82 kilometers. This is a large number, but still incomparable to catastrophic visions straight from S-F movies.
If the explosion of an atomic bomb does not bring with it the total annihilation of entire cities, what is the danger? If most of the people who hid behind the thick walls of the apartments survive, where's the catch? In radioactive fallout.
Description of zones:
1. Red zone: 5 Sv / hr - within one hour we get a dose value that is lethal for 50% of the population.
2. Orange zone: 500 mSv / hr - within an hour we will receive the maximum dose prescribed by Polish law. Such a dose can be obtained in the case of an action saving human life. This is a value that should be remembered - we can treat 500 millisieverts as an absolute safety limit, the maximum dose that we can take in an emergency, which is undoubtedly an explosion of an atomic bomb.
3. Bright orange zone: 100 mSv / hr - within one hour we will get the dose limit value that can be obtained in the case of rescue operations.
4. Yellow zone: 20 mSv / hr - within one hour we will obtain the limit value of the dose that a worker exposed to radiation may receive within one year.
Taking into account the above points, we can say that the maximum time we can spend in the orange zone is one hour, and in the bright orange zone - 5 hours. In the case of the red zone, going beyond the relatively safe limit of 500 mSv is a matter of a few minutes.
Regarding the second scenario, the detonation of a 1000 kilotons payload at 2.5 km would not result in significant radioactive fallout. For this to happen, the explosion must be closer to the ground, preferably at the surface. Here is the contamination map in this case:
It's getting scary slowly. A thousand square kilometers of land will be contaminated to such an extent that only those who have adequate shelter, supplies, and specialist knowledge (which you can get on our website) have a chance to survive. For the next six thousand square kilometers, the situation will not be much better, although the chances of a successful evacuation are better. Let's be honest - we cannot prepare for the direct effects of an atomic bomb or prevent them in any way. However, if we survive a nuclear explosion, there is a high probability that radioactive fallout will fall on us, which kills us silently and invisibly. Only those who are prepared for it will survive.
All simulations were calculated on NUKEMAP 2.7 by Alex Wellerstein (simulation date - 03/05/2020). Run your own simulation and see how big the fallout will be in your town! Find NUKEMAP here!
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