Nuclear Energy Essay, Research Paper
Table of contents
Page 1:The development of nuclear energy.
Page 2:What is nuclear winter.
Page 3&4:Effects of nuclear weapons.
Page 5&6: parts of a nuclear reactor.
The development of nuclear energy
In 1972, scientists discovered a natural chain reaction had occurred nearly 2 billion years ago in a uranium deposit in the west-central part of Africa. Two billion years ago, radioactive decay had not progressed so far a sit has today because of this, he are contained enough U-235 to start a chain reaction. An accumulation of ground
water acted as a moderator to begin the reaction. The heat
from the reaction wormed up the water which turned the water into steam, less and less water was available this
means that the moderator ran out and the reaction died out. Except for such rare occurrences, such as, nuclear energy was not released on a large-scale on earth until 1942. That year scientists produced the first artificially
made chain reaction. Scientific discoveries that took place
within the last 100 years made the large-scale release of
nuclear energy possible.
What is nuclear winter
Nuclear winter is the deadly world environmental effects that could result to a major nuclear war. A war like this could bring on nuclear winter by drastically changing
the earths atmosphere and climate. Nuclear winter could start to develop from city fires created by extreme heat of nuclear explosions. Large amounts of smoke from these fires could spread out and cover at least half the earth’s
surface. The smoke would block out sunlight from reaching the ground. Temperatures could drop drastically,
and rain fall could be reduced. This might last up to several months or years. With less sunlight, less rain, and
low temperatures, farming could stop, and world wide
famine could result. Nuclear winter would reduce the thickness of the earth’s ozone layer which protects people
and other living things from the sun’s violent ultraviolet
light. Scientists say that in a nuclear war it would kill an
estimate of 500 million people, but 4 billion more will starve and die because of nuclear winter.
Effects of nuclear weapons
Nuclear weapons devices can have a wide variety of
yields. Some older bombs have yields of about 20 megatons. A megaton is the amount of energy released by one million short tons of TNT. Today, most nuclear devices have yields of less than one megaton. The effects that nuclear explosions have on people, buildings, and the environment can vary greatly, depending on a number of factors. These factors include weather, terrain, the point of explosion in relation to the earths surface, and the weapon’s yield. The weapons produce four basic steps.
(1)Blast wave: the explosion begins with the formation of a fire ball which consists of a cloud of dust and extremely hot gasses under very high pressure.
(2)Thermal radiation: this is made up of ultraviolet, invisible, and infrared radiation given off by the fire. This can cause eye injuries as well as skin burns, also called flash burns.
(3)Initial nuclear radiation: this form of radiation is given off within the first minute after the explosion. It is made up of neutrons and gamma rays. The neutrons and gamma rays are released from the fire ball instantly after the explosion. The rest of the gamma rays are given off by a huge mushroom cloud of radioactive material that is formed by the explosion.
(4)Residual nuclear radiation: this form of radiation is given off later on after the explosion. It is created by fission and is made up of gamma rays and beta particles(electrons) . Residual radiation is produced by fusion which is mainly made up of neutrons. It strikes particles of rocky soil, water, and other materials that make up the mushroom shaped cloud.
Parts of a nuclear reactor
Nuclear reactors vary in design and size. But most of them have the same five basic parts.
(1) The core: the central part of the reactor which is made up of nuclear fuel. This is where the fission process occurs.
(2) The moderator: this is a material used in many reactors to increase the probability of fission and therefore promote a chain reaction. Most moderators are made up of graphite, water, or heavy water, a compound of oxygen deuterium. Such a substance slows down the neutrons released by the U-235 atoms during fission. By this happening, the moderator enables other U-235 atoms to capture and more readily split the neutrons in turn.
(3) The control rods: these regulate the rate of the chain reaction. They are made up of boron, cadmium, or some other element that can absorb neutrons without being charged by them.
(4)The coolants: these carry the intense heat produced by fission out of the reactor. At the same time, the coolant controls the temperature of the reactor core and prevents it from overheating . Different substances, including gasses, liquids, and liquid metals can be used as coolants.
(5)The pressure vessel: htis holds the core of most reactors. It also contains the circulation channels for the reactors coolant.
Nuclear reactors also have a biological shield and a safety system . The biological shield is made up of thick concrete blocks that surround the pressure vessel. This shield protects reactor operators and technicians as well as the general public from radiation exposure . The concrete absorbs the gamma rays and neutrons that escape from the pressure vessel.
The safety system has devices designed to prevent serious reactor accidents. It has a set of safety rods that permits rapid shut down of a reactor. These rods, which act like control rods, are automatically inserted into the reactor core when the neutron counting instruments detect an abnormal increase in the rate of fission. The reactor will then shut down.