Реферат: Nuclear Wastes Essay Research Paper What is

Nuclear Wastes Essay, Research Paper

What is nuclear power and what does it produce? Nuclear power is energy given off from a splitting atom and it produces heat, wastes, and electricity if used properly. Electricity is the main use for nuclear power, but baking electricity from nuclear power depends on how the reactor works, the storage of its wastes, the different kinds of power plants, and the dangers and accidents in nuclear reactors. There is a good advantage to nuclear power plants and that is; that they have an endless amount of power, however, the down fall is what to do with the left over Uranium.

The electricity produced from nuclear reactors can be said to be simple but it is not all that. There are one-half inches pellets made of Uranium-235, which are put into a tubing (Galperin 30-31). The pellets are sometimes made of Uranium dioxide. The uranium dioxide is a very tough ceramic substance and has a melting point of 2,746?C (5000?F) (Hyde 34). The tubes are about fourteen feet in length and are put into a group of 2000 and bundled up into metal frames to make the fuel assembly. When they are in the reactor and ready the reactor starts and a neutron hits an atom which makes the atom split, and those particles hit other atoms in which they split more atoms and so on. When the atoms split they create heat and water surrounds the tubes and then the water gets heated up and turns to steam which then turns turbines which makes electricity (Galperin 30-31). In order to control the reaction rate there are control rods inserted into the core. The control rods are the reason the reactor doesn?t stop on its own (Galperin 104). Radium and Uranium are the two most common atoms used in nuclear reactors because they split in nature easily. Uranium-235 has ninety-two protons and 143 neutrons, but is less stable than Uranium-238 with ninety-two protons and 146 neutrons. The two isotopes act the same chemically but have a different number of particles in their nuclei and their atoms don?t weigh the same (Hyde 10). Storage is also apart of the procedure as well. When the fresh fuel rods are removed from the reactor, most of them are not highly radioactive. Most of their radiation is from the uranium pellets, and this radiation is so low that it can be stopped by a piece of paper at a short distance. However, some nuclear trash in spent fuel rods is so radioactive that it has to be removed by remote control and stored by remote control (Hyde 37). The spent fuel rods are temporarily stored in concrete basins until permanent storage facilities are found. These basins are filled with forty feet of water. The water circulates the spent fuel rods removing heat and stopping neutrons from reacting (Hyde 38). In the 1980’s and before there was no place to dispose of the wastes from nuclear power plants, but, in the 1990’s there is supposed to be constructed cylinders at the depth of 1,970 feet (600 meters) where the waste can be buried. The cylinders are to be constructed where there are no earthquakes or ground water (Goode 55). If ground water did appear where the cylinders were it would take thousands of years for water to penetrate the rock in which the cylinders are embedded. When the water does reach the cylinders, radioactivity would escape very slowly, and it would then take thousands of years for water to reach the surface. After all this time it would be almost harmless (Goode 55). Before the fuel rods are stored, they must be transported carefully. There had been thoughts of accidents when transporting spent radioactive materials, so there has been some major thinking so that radioactive material doesn?t leak from an accident. First, the spent rods cannot be transported until six months later, this reduces the toxicity of the material. There is only a small amount of radioactive material shipped at one time. So that if an accident were to occur and radioactive material was released it would be only small amounts of radiation (Goode 54). There has been some major planning in designing a canister to carry the radioactive material. The canisters cost more than $2 million apiece. These canisters can resist a 30-mph head on collision. It can with stand gasoline fire for thirty minutes, immerse in water for eight hours and a puncture test (Goode 54). There are several different kinds of nuclear power plants, but their concepts are the same. In a water-cooled reactor water surrounds the fuel rods, carrying any heat. The heated water is carried away from the core to an exchanger where other water is heated, turning to steam that is used to turn turbines and make electricity (Hyde 35). A Pressurized-water reactor is the most common reactor in the U.S. The water is kept under a great amount of pressure so that it will not turn to steam under the high temperatures that are reached in the reactor core (about 315? C, or 600? F). The water is then pumped to the steam generator and the turbine. From the turbine the water is then condensed to it nature liquid state and is then put back into the reactor (Goode 39). Heavy-water reactors contain large amounts of Hydrogen isotope deuterium so that it can absorb a smaller number of neutrons than ordinary water. This reactor uses nonenriched uranium unlike the Boiling-water and Pressurized water reactors that use the enriched uranium which is more costly (Goode 42). In Boiling-water reactors cool water is placed in the reactor core where it is heated to boiling point under high pressure. The steam rises to the top of the reactor and is carried to a turbine that produces electricity. The Boiling-water reactors eliminate the double delivery system of Pressurized-water reactors where coolant heats a second supply of water to turn the turbine. The Boiling-water reactors are larger than the Pressurized-water reactor in order for it to produce the same amount of electricity (Goode 42). The High-temperature gas-cooled reactor has a helium or carbon dioxide gas used as a coolant. The Graphite (carbon) is used as the moderator (Goode 42). A moderator is a substance such as heavy water or graphite, used in nuclear reactors to slow neutrons, enabling them to penetrate uranium nuclei more easily, there by causing fission (Galperin 104). Helium and carbon dioxide allow the core to have higher temperatures than the other reactors with ordinary water or heavy water. These reactors are more efficient at producing electricity than other type of reactors. These types of reactors are the most popular in Europe than any other country (Goode 42). There are also Organic-cooled reactors that use organic liquid as a coolant. It does not need enriched uranium as fuel, and it can reach to temperatures as high as the High-temperature gas-cooled reactor. It also does not need high pressure in the core like some of the other reactors. The organic liquid is cheaper than heavy water, but, it has higher absorbsion ability of free neutrons and is flammable (Goode 43). The procedure includes from the making of nuclear power to the disposal of its wastes, and before the 1980’s the nuclear engineers didn?t even finish the procedure because they did have a place to store the waste. The procedure of nuclear power is more detailed and hi-tech than what is mention only because it is too complex.

There are many statistics about nuclear power only because of the concerned engineers and the public. To make nuclear energy, atoms have to be radioactive. To make an atom radioactive it has to be split, but that is not easily done. Scientists have estimated that there are more than 100 million atoms spread over the head of a pin. To make an inch of copper it would take a 100 million atoms to stretch an inch. Atoms are not the same size as other different atoms, which is why it would take 100 million atoms of copper to make an inch and 100 million aluminum atoms to spread over the head of a pin. The aluminum atoms are small in diameter than the copper atoms (Hyde 7). There are several kinds of radiation, there are Gamma Rays that are thought to be a burst of energy, a particle or a wave. Gamma Rays are emitted at the same time as beta particles, such substances are part of the radioactive waste (Murray 17). There are two common particles of radiation, one is the alpha particle and the other is the beta particle. The alpha particle is radiation in the form of a subatomic particle composed to two protons and two neutrons. A beta particle is radiation in the form of a high-speed electron (Galperin 104). There is also the X-rays which is also a kind of radiation. X-rays are most commonly used in hospitals. Too much of X-rays along with Gamma rays can cause cancer. After X-rays is ultra violet light and visible light. Ultra violet emits some radiation, it is found in the sun?s rays and too much sun has been known to cause skin cancer, only because of the ultra violet radiation (Murray 18). They?re two classifications of wastes. Commercial wastes are those produced by reactors. There is only a small volume of waste because most of the fuel from power reactors has been left in the form of irradiated fuel assemblies. The fuel remains highly radioactive for many years after it has been taken from the reactor. Defense wastes are from periods of World War II (Murray 60). By the year 2000 there is expected to be enough nuclear trash to fill a four-lane highway stretching from the East coast to the West coast one foot deep. It is estimated to be about 1 billion tons of trash (Hyde 1). The amount of electricity that the nuclear fuel provides is about 30% of the U.S. electricity demanded by 1990. The average reactor provides the same amount of electricity as that from 10 million barrels of oil or 3 million tons of coal (Hyde 4). There are not only nuclear wastes that affects the U.S., there are also financial wastes. Nuclear energy is also used in ships. Nuclear energy is more cheaply than oil. Just plain uranium is not expensive but a few hundred pounds of uranium that winds up in the core of a modern nuclear submarine costs about $3,500,000 (Dukert 23). Actually, 19.1% of the U.S. electricity is supplied from nuclear energy. This country has the least power from Nuclear Energy compared to all the major countries. France is powered from nearly 74.6% from nuclear energy (Galperin 21).

There are many people affected by the use of nuclear reactors or radioactive material. Radioactive material has especially effected people in the work force. Long ago before radioactivity was determined to have bad effects, women would paint radium on the dials of watches and airplane instruments. Many women made their brush point by twirling it on their tongue. Within five hears women started to have bone cancer. 28% of 5000 women developed cancer of the bone (Hyde 23). In the Nuclear power plants there are safety procedures for the workers. “Today workers in nuclear plants are monitored by radiation badges that record their exposure and by other instruments that help health physicists to maintain records of exposure.”(qtd. Hyde 23). It is still being argued of how much should a person be allowed to be exposed to radiation (Hyde 23). In the summer of 1978 radioactive contaminations were found at a number of sites where atomic energy had formerly been explored. At Canonsburg, Pennsylvania an industrial park was built in a area where about 1000 tons of waste was buried in 1957. About 120 workers in that area had been exposed to low level radiation (Hyde 28). People receive a certain amount of radiation or dosage. Consider where a person lives, at sea level it is 40 millirems or .004 rems. Rems is a measurement of radiation. Add 1 millirem for every 100 feet of elevation. Then add about 93 millirems because of the average exposure to cosmic rays. Add 35 millirems if the person lives in a wood house, add slightly more for concrete and brick, and stone walls will increase count from 50 to 100 millirems. Add 15 millirems for background radiation and 25 millirems for food. There are more ways to gain radiation into someone?s system, but it is not sure how much millirems are too much (Hyde 13-14). “Exposure to instananeous radiation (gamma rays and neutrons) causes sickness and, possibly, death. At relatively low doses, it damages blood cells. At higher doses, damage occues to gastrointestinal tract, and at very high doses injury to the brain. Suppression of the body?s immune system is recognized as a consequence of radiation over-exposure.” (qtd. www.who.ch/press/1995/pr95-69.html). There were several minor nuclear accidents but, any nuclear accident is not minor. In an electric plant a steam generator piping had ruptured. Previously the Atomic Energy Commission (AEC) had declared that this kind of accident would not occur in the Wisconsin, Point Beach on Lake Michigan (Goode 76). In Sept. 1974 the AEC closed down 21 of 50 nuclear plants working in the country to check for leaks in pipes. Leaks were discovered in two reactors and cracks found in a third (Goode 76). In 1971 tests at the Oak Ridge laboratories showed that fuel rods commonly used in reactors would buckle, swell, and rupture a t temperatures far lower than they would have to with stand during a loss-of-coolant accident. As a result the tests were ceased although they had revealed dangerous problems for some unknown reason (Goode 75). A Zion station nuclear plant near Chicago, had opened in 1973. The plant had been closed down a few months after it was open because bad wiring was found in the cooling system (Goode 75). In 1971 about 5000 home owners in Grand Junction received letters saying that Uranium tailings have been found on their properties. The radiation exposure level was to high that corrective action had to be taken. The radioactive tailings were removed from beneath the foundations at government expense (Hyde 28). There was one major accident that had occurred with a nuclear plant in the U.S. that is remembered today. On March 28, 1979, a nuclear reactor had begun to leak radioactive gas that morning. The governor had ordered the pregnant women and children be evacuated from the immediate area. Thousands of other people had left, but, reporters had came from around the world to get their story. The radioactive gas had continued to leak and the experts didn?t know how the radiation would effect the surrounding neighborhoods. The experts had hoped to confine most of the dangerous radioactivity to the plant itself, where it could later be disposed of. There were two major problems that had occurred. There had been a hydrogen bubble that had formed in the reactor. The hydrogen bubble had threatened to explode sending large amounts of highly toxic radioactive substances into the air. This had became the most important problem the scientists and engineers had to solve. However, the hydrogen bubble did not explode. The other problem that had occurred was the possibility of a meltdown. The heat in the core temperature had begun to rise and there was nothing really working to stop it from the temperature rising (Goode 10-11). “In the reactor 1,500 gallons of water had to be added each day to replcae the 1,500 gallons that continued to leak daily into the containment sump (qtd. Stephen 225). A meltdown is when the core of the reactor becomes so intense that it melts through the floor and sinks into the ground until rock and dirt cools it off. The problem about a meltdown is that it would pollute the underground water supply. Fortunately, the intense heat did not cause a meltdown. After the incident known as the Three-Mile-Island in Central Pennsylvania the investigation had taken place. As a result of the investigation had concluded that there was human error along with mechanical error as well. They had also said that if the hydrogen bubble did explode that it would not of had been strong enough to destroy the reactor containment or the hard rock underneath the core, and allowing no additional radioactive substance into the air (Goode 11). As a result I believe there are accidents that will happen but at what expense. I do not want a catastrophe because of a nuclear power plant. If there is a safer way to make electricity at the same amount then it would be done, but there is not so we have to cope with it.

Nuclear power does produce waste, electricity, and problems, but so does gas and coal. There is a good advantage to nuclear power plants and that is; that they have an endless amount of power, however, the down fall is what to do with the left over Uranium. People may think that nuclear power is bad because of radiation. But in fact “Radiation has been defined as energy moving through space invisible waves. Life could not exist without heat and light radiation from the sun.” (qtd. Hyde 21) and this does make sense, since your body is used to radiation it would probably take a while to get used to without it. Nuclear power is not very bad as long it doesn?t into the wrong persons mind, is what a few people would say, but they could not make a nuclear bomb from the knowledge of how nuclear power plants work. “Using nuclear power gives us more variety in fuel sources. It helps us avoid being dependent on other countries for only one or two types of fuels.” (qtd. www.nuc.umr.edu/~ans/pages1-10.html#page10). As for what I think of nuclear power, I think that it has its advantages and also its disadvantages so they almost even out. Using nuclear would be better because gas and coal produce more physical waste than nuclear power, but, there is always a risk in anything you do. Those risks might be big and they might be small, but they are always risks that are taken.

Works Cited

Dukert, Joseph M… Nuclear Ships of the World. New York; Coward, McCann & Geohegan, Inc.


Galperin, Anne L… Nuclear Energy, Nuclear Waste. New York; Chelsea House Publishers 1992.

Goode, Stephen. The Nuclear Energy Controversy. New York; Franklin Watts 1980.

Hyde, Margaret O… Everyone?s Trash Problem: Nuclear Wastes. New York; McGraw-Hill 1979

Muray, Ramond L… Understanding Radioactive Waste. Columbus, Ohio; Battelle Press 1994.

Stephens, Mark. Three Mile Island. New York; Random House 1980.

Uknown, www.nuc.umr.edu/~ans/pages1-10.html#page10; “Do we really need nuclear power to generate electricity?”, November 25, 1996, Unkown Publisher.

Uknown, www.who.ch/press/1995/pr95-69.html; “Nuclear weapon testing.”, November 25, 1996, Unknown Publisher.

еще рефераты
Еще работы по на английском языке