Nuclear Weapons

In 1940, the United States government invested $40,000 to construct a system designed by Enrico Fermi to develop a self sustaining chain reaction. This would prove to be the key to unleashing the power of the atom. Einstein was not the creator of the atomic bomb, but without his discoveries and formulas, the bomb would never have been created. The US government arranged the secret creation of the atomic bomb. They called it the Manhattan Project. Fermi’s understanding of when mass is converted to energy, the amount of energy converted would be an enormous amount. It took 856 days from the first controlled nuclear fission experiment, to the first detonation of a nuclear explosion at the Trinity site in New Mexico. The first step for a nation to create nuclear weaponry is to acquire an adequate supply of fissile materials. This is the most crucial part.

In atomic fission bombs, there are several components which when combined in the precise order, cause an atomic explosion. One of these materials is known as fissile material. Fissile material can be extracted from uranium or plutonium. After extraction, fissile material is to be enriched, or separated, from lesser fissile isotopes because only a small percentage of uranium and plutonium ore even contain fissile material. There are two types of uranium isotopes used and only one type of plutonium isotope used in an atomic fission explosion. These isotopes are U-235 and U-238, with Plutonium-239. Uranium has much more fissile material than plutonium and is often times the main component when creating a fission bomb. Although plutonium does generates more energy, there is much less of it found in nature and therefore harder to obtain.

When creating atomic fusion bombs, the materials used are similar to that of a fission bomb. A small amount of fissile material is needed for an initial explosion, but helium isotopes are also used to create the bulk of the explosion. These isotopes are known as tritium and deuterium. They combine with a plutonium, or uranium rod for a second explosion. The result of the explosion is helium isotopes, H-3 and H-4.

Fission bombs work when an atom of uranium or plutonium is bombarded with many neutrons moving at high speeds. When these neutrons make contact, and enough force is applied, the atom splits, also known as a cross section, and emits a tremendous amount of energy. The initial cross section sends two or three other pieces flying away from each other. This separation causes several other neutrons to go flying off from the original plutonium or uranium atom. These neutrons then collide with other atoms of uranium or plutonium causing a chain reaction. The massive amount of energy released emits gamma radiation and causes a visible explosion. “At first glance, making a fission bomb is simple: assemble a supercritical mass of fissile material and a chain reaction will rapidly produce neutrons that, in turn, generate more fission and neutrons. The challenge is to bring two subcritical masses together quickly before the energy released by the initial fission blows the masses apart and stops the chain reaction”.

Fusion bombs work a little differently then fission bombs, in the sense that it is a combination of atoms rather then the splitting of them. The combination of two hydrogen isotope atoms results in a helium isotope. When combined, a huge amount of radiation and energy is given off. When theorizing the design of this bomb, the scientists came across many problems. The problems were that the gases used had a short half life, were hard to store, and needed to be compressed at high temperatures to initiate the explosion. Stanislaw Ulam solved two of these problems. He recognized that most of the radiation is X-rays. These X-rays provided the high temperatures and pressures needed to contain the gases. Therefore encasing a fission bomb, inside a fusion bomb, two of the problems were solved.
The steps that are necessary for a successful explosion are:

The fission bomb imploded, giving off X-rays. These X-rays heated the interior of the bomb and the tamper; the shield prevented premature detonation of the fuel. The heat caused the tamper to expand and burn away, exerting pressure inward against the Lithium Deuterate. The Lithium Deuterate was squeezed by about 30-fold. The compression shock waves initiated fission in the Plutonium rod. The fissioning rod gave off radiation, heat and neutrons. The neutrons went into the Lithium Deuterate, combined with the Lithium and made Tritium. The combination of high temperature and pressure were sufficient for Tritium-Deuterium and Deuterium-Deuterium fusion reactions to occur, producing more heat, radiation and neutrons. The neutrons from the fusion reactions induced fission in the Uranium-238 pieces from the tamper and shield. Fission of the tamper and shield pieces produced even more radiation and heat. The bomb exploded.

Explosions aren’t the only deadly part of an atomic bomb. There are hazardous effects from the radiation. The severity varies depending on how close one is to the site of impact. Four different things that cause damage when an atomic bomb hits are, heat, pressure, radiation and radioactive fallout. Where the bomb touches the ground and explodes is known as the hypocenter. At the hypocenter, everything is immediately vaporized due to the extreme heat and pressure. It can get as hot as 300 million degrees Celsius at the hypocenter. Everything within range of the explosion is obliterated. Outside the hypocenter, the remnants after an explosion is horrific. Trees can be uprooted, houses knocked over, and apartments torn apart. The radioactivity and radioactive fallout also have devastating long term effects. They usually consist of nausea, vomiting, and diarrhea. Cataracts, hair loss, and loss of blood cells are some of the more severe conditions. The radiation left behind also increases the risk of certain diseases for the people that inhabit the area. Leukemia, cancer, infertility and birth defects are some of the diseases and defects that are caused by the radiation.

Atomic bombs are the world’s deadliest weapon known to date. They can also be considered chemical weaponry due to their long term effects and radiation, but are mostly known as nuclear weaponry. Although the make up and materials of fission and fusion bombs differ considerably, fissile material is a necessary component to both of the bombs. This makes uranium and plutonium highly valuable. Even though a fusion bomb may be more efficient then a fission bomb, it is at a disadvantage because its contents have a short half life. The destruction of all nuclear weapons travels far beyond the original target, thus making nuclear weapon control a major issue for all governments. This was the case during the Cold War when the US and Russia both had nuclear weapons and were threatening each other. Countries still monitor each other for the creation of nuclear weapons, because the detonation of an atomic bomb could have catastrophic effects for the entire planet.

Sources
The Ultimate Weapon the Race to Develop the Atomic Bomb by Edward Sullivan
Weapons of Mass Destruction and North Korea
http://www.chemcases.com/nuclear/nc-09.htm

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