Although many don’t view a nuclear event as a likely disaster scenario, it’s important to learn about all the possible issues that may impact your family in uncertain times. Given the instability in the Korean Peninsula and elsewhere, the issue of nuclear blasts and the radiation they emit is a timely subject.
Understanding the Definition of Radiation
The quick definition of radiation is energy given off by unstable matter in the form of rays or high-speed particles. The following is some basic chemistry paraphrased from the U.S. Nuclear Regulatory Commission (US NRC): All matter, including you, is composed of atoms. Atoms are made up of various parts; the central nucleus contains minute particles called protons and neutrons, and the atom’s outer shell contains other particles called electrons. The nucleus has a positive electrical charge, while the electrons have a negative electrical charge. Neutrons are, well, neutral. These entities work within the atom toward a stable balance by getting rid of excess atomic energy (called radioactivity). Unstable nuclei want to become stable and may emit energy; this emission is what we call radiation.
Types Of Nuclear Weapons
Until the recent missile launches by North Korea, most people were concerned about the use of “dirty bombs“ by terrorists. A dirty bomb is not technically a nuclear weapon. It uses conventional explosives to disperse radioactive material in the general area. Usually, the effect of the explosion causes more damage and casualties than the radioactive elements.
Our concept of an “atomic bomb“ as developed by the Manhattan Project in the 1940s is one that uses “nuclear fission”. The explosion is caused by a chain reaction that splits atomic nuclei. The result is a wave of intense heat, light, pressure, and kinetic energy equaling thousands of tons (also called kilotons) of TNT. This is followed by the release of radioactive particles in a cloud that resembles a mushroom (if a ground blast). Mixed with dirt and debris, the particles fall back to Earth, contaminating crops, animals, and people. This will happen in the area of the detonation but will also be blown elsewhere by the prevailing winds.
Atomic bombs gave way to hydrogen bombs. These are best described as “thermonuclear” weapons due to the generation of extreme heat during detonation. H-Bombs use a process known as nuclear fusion, which takes two light nuclei and forms a heavier one, using variations of hydrogen atoms called “isotopes”. This fusion process requires high temperatures and usually involves a fission reaction as discussed above to initiate. H-Bombs don’t just generate power in the kilotons; they can reach levels in the megatons (millions of tons) of TNT.
Another type of thermonuclear weapon is the “neutron bomb“, which generates much less kinetic energy and thermal damage but much more radiation. Enhanced radiation weapons like the neutron bomb generate a fusion reaction that allows neutrons to escape the weapon with only a limited blast. Originally designed by the United States to counter massive Soviet tank formations, the neutron bomb is an example of a tactical nuclear weapon. The effect is to leave infrastructure mostly intact while wiping out human targets due to massive radiation.
Damage Caused By A Nuclear Attack
The impact of a nuclear bomb is dependent on its “yield”—a measure of the amount of energy produced. The Hiroshima A-Bomb had a yield of 15 kilotons, while the “Tsar Bomba”, detonated by the Russians North of the Arctic Circle in 1961, had a yield of 51 megatons (51,000 kilotons!). Most of the weapons stockpile of the U.S. and Russia consist of bombs in the 100 to 500 kiloton range, much stronger than Hiroshima and much weaker than Tsar Bomba. This is because they are meant to be fired at major cities in clusters rather than one large bomb, which would be easier to intercept than, say, 20 smaller ones.
What Causes Damage
Damage is caused by:
- Blast effects (kinetic energy) – damage due to the explosion and resulting shock wave
- Heat (thermal energy) – damage generated by extreme heat
- Radiation (initially and later via fallout) – both local and, later, far-reaching
- Electromagnetic pulses (EMPs) – disrupts telecommunications, infrastructure
You can expect a generally circular pattern of local damage, but various factors come into play besides the yield of the weapon. The altitude of the explosion, weather, wind conditions, and nearby geologic features play a role. The U.S. government estimates the distribution of damage for fission bombs as the following:
- 50% shockwave
- 35% heat
- 5% initial blast radiation
- 10% fallout radiation
Examples of Damage on Hiroshima and Tsar Bomba
The atom bomb dropped on Hiroshima in 1945 flattened buildings over a roughly four square mile area and killed 60,000 people immediately. Another 90,000-140,000 succumbed later to injuries and radiation exposure. Although this represents a total of 150,000 to 200,000 fatalities, the entire population did not perish. At the time of the explosion, there were about 350,000 people in Hiroshima, including 43,000 soldiers. This shows that, although horrific in its effects, that distance from ground zero and other factors play a role in a nuclear weapon’s lethality, as does the power of the bomb itself.
A 50 megaton H-Bomb like the Russian “Tsar Bomba“, however, would cause a much larger circle of devastation than the Hiroshima bomb, with widespread fatalities at least 20 miles from ground zero and third-degree burns 50 miles away. Windows were reported shattered from the test detonation as far away as Norway and Finland.
Types Of Radiation From Nuclear Blasts
This article will concentrate on the effects of radiation exposure. Put simply, radiation is divided into “ionizing” and “non-ionizing”. We are bombarded daily by radiation from multiple non-ionizing sources: the sun’s visible light and heat, microwaves, radio waves, radar, and others. This type of radiation deposits energy in the materials through which it passes, but it doesn’t break molecular bonds or destabilize atoms. These effects, however, can be caused by ionizing radiation, where the atom becomes charged and unstable, which is not a healthy state for living cells.
There are several types of radiation given off by a nuclear weapon: Alpha, beta, and neutron particles, and gamma and X-rays. All are caused by unstable atoms, which, in order to reach a stable state, must release energy in the form of radiation. Atoms can do this by, for example, shedding electrons, which causes them to become ionized.
Alpha radiation occurs when an atom undergoes radioactive decay, giving off an alpha particle. Due to their charge and mass, alpha particles only travel a few centimeters and don’t even penetrate the outer layer of skin. If ingested, inhaled, or somehow injected, however, alpha particles are capable of causing considerable damage to living cells.
Beta radiation takes the form of particles. Due to the smaller mass, it is able to travel further in air than an alpha particle, but it can be stopped by a thick piece of plastic, a stack of paper, and even clothing. It can penetrate a short distance into exposed skin, though, causing “beta burns“,m which may require treatment. However, the main threat is from ingesting it, perhaps from crops growing in fallout areas.
Gamma and X-ray Radiation
Gamma and X-rays, unlike alpha or beta, are two types of radiation that do not consist of any particles at all but instead are pure electromagnetic energy. Think of gamma rays as X-rays on steroids. Gamma radiation can travel much farther through air than alpha or beta particles (which have mass) and is responsible for the most ill effects on humans after a nuclear explosion. It can, however, be blocked by various materials.
Lastly, neutron radiation consists of high-speed particles with high penetrating power. Neutron particles travel further in air than other forms of radiation but can be blocked by materials that contain hydrogen, such as water (H₂0) and concrete. When neutron particles are absorbed into a stable atom, they make it unstable and more likely to emit radiation. Therefore, it’s the only type discussed here that can turn other materials radioactive.
Radiation Effects On Living Things
Atomic weapons can decimate a population from thermal blasts, but it also causes illness and death due to exposure from radiation. Although populated areas have experienced detonations only twice, (Hiroshima and Nagasaki in 1945), nuclear reactor meltdowns and other events have occurred from time to time since then, such as in Fukushima in 2011 and Chernobyl in 1986.
Deaths and Injuries Near Ground Zero
In an atomic explosion, radiation is just one of the possible causes of casualties; heat effects and kinetic energy damage near the blast will cause many deaths and injuries. Radiation released into the atmosphere, however, can have devastating effects far from “ground zero”.
Fallout Effects On Food Supply and Animals
A nuclear event produces “fallout”. Fallout is the particulate matter that is thrown into the air by the explosion. It can travel hundreds (if not thousands) of miles on the prevailing winds. It coats fields, livestock, and people with radioactive material.
The higher the fallout goes into the atmosphere, the farther it will travel downwind. This material contains elements that are hazardous if inhaled or ingested, like Radioiodine, Cesium, and Strontium. Even worse, fallout is absorbed by the animals and plants that make up our food supply. In large enough amounts, it can rapidly become life-threatening. Even in small amounts, it is hazardous to your long-term health.
Nuclear Power Plant Meltdown
A nuclear power plant meltdown is usually less damaging than a nuclear blast. The radioactive material doesn’t make it as high up in the sky as the mushroom cloud from an atomic bomb. The worst effects will be felt by those near the reactors. Lighter particles, like radioactive iodine, will travel the farthest. These are the main concern for those far from the actual explosion or meltdown. The level of exposure will depend on the distance the radioactive particles travel from the meltdown and how long it took to arrive.
Tomorrow, we will continue with Part 2 and begin by talking about radiation sickness, protection, remedies, and actions.