Реферат на тему Nuclear Science
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Nuclear Science – Drawbacks Or Advantages? Essay, Research Paper
Scientists and engineers have found many uses of nuclear chemistry, and how to use this energy in a peaceful manner. The various uses are beneficial to many countries and contribute to the overall welfare of those utilizing the nuclear energy sources. Benefits include: conservation of fossil fuels, lowered economic energy costs, and decreased contribution to the adverse greenhouse effect. Nuclear chemistry and nuclear reactions have constantly been utilized to improve the quality of life over the past twenty-five years.
There have been many implementations of nuclear chemistry all over the world. Nuclear chemistry has many beneficial aspects for the future and conservation of energy and resources. The great advantage of nuclear power is its ability to produce enormous energy from a small volume of fuel. About one ton of nuclear fuel produces about two to three million tons of energy that could be obtained from a fossil fuel. According to the World Health Organization (WHO), “Substituting small, properly contained volumes of nuclear waste for vast, dispersed amounts of toxic wastes from fossil fuels would produce so obvious an improvement in public health that it is astonishing that physicians have not already such demanded such a conversion. Before the advance of nuclear chemistry, electricity was mainly generated through the use of fossil fuels that produce noxious greenhouse gases (Dennis, 39).” Nuclear chemistry has been an alternative means of energy, mainly used in thermal power plants to help in generating electricity.
Using fossil fuels as energy sources has had deleterious effects on our environment and has caused global warming. Tree removal and increased burning of fossil fuels is the depleting ozone and affecting the mixture of gases in the atmosphere; gases such as: methane, nitrous oxide, and carbon dioxide. All of these gases trap heat and contribute to the yearly increase in temperature. Additionally, nuclear plants can be less expensive to operate than a fossil fuel plant, mainly because nuclear plants use a much smaller volume of fuel. The average production cost for 1 kilowatt-hour (kWh) is only 1.9 cents, while the average production cost for electricity produced from gas costs 3.4 cents per kWh. Due to all these negative points about fossil fuel use, less and less of fossil fuels and more nuclear power is used.
Also, radiation exposure due to waste produced from nuclear energy has reduced tremendously. Nuclear reactors work somewhat like a furnace. Instead of burning fuel in the reactors, they actually go through the processes of fusion and fission–splitting of nuclei into two. In a reactor, uranium atoms are split apart in a controlled chain reaction. In a chain reaction, particles released by the splitting of atoms strike other uranium atoms splitting those. Those particles given off still split other atoms in a chain reaction. This causes a pound of uranium to release more energy than the burning of 3 million pounds of coal.
The process of fision wherein the atoms keeps opn splitting
There are basically three types of nuclear reactions that can release useful amounts of energy, which give off heat, light, and other radiation. This heat can be used to make steam, which can further generate electricity.
The nuclear power plant exterior
AND
How electricity is generated using nuclear energy
These reactions are radioactive decay, nuclear fission, and nuclear fusion. Nuclear energy is called fusion. Fusion means joining smaller nuclei to make a larger nucleus. The sun uses nuclear fusion of hydrogen atoms into helium atoms. Nuclear reactors also produce artificial radioactive isotopes, which produces much energy. This radiation accounts for about 10 percent of the energy produced within the reactor. To control and protect nuclear energy, scientists are working on controlling nuclear fusion by attempting to build a fusion reactor to produce electricity. When the energy is released all at once, it makes a tremendous explosion like an atomic bomb.
Nuclear chemistry is used in generating electricity and involves many applications of radioisotopes. Radioisotopes are powerful tools for studying processes in biochemistry, medicine, materials science, meteorology, and many other fields. A tracer, which is a chemical “beacon” that emits non-ionizing radiation to signal the presence of the substance, is useful for many purposes (Silberberg, 1064). Chemists and engineers use tracers in the studies of solid surfaces; material movements in semiconductor chips, paints, and metal plating; in detergent action and also in the process of corrosion, etc. (Silberberg, 1065). The usefulness of tracers has also been noticed by hydrologic engineers in the study of the volume and flow of large bodies of water; and the study of surface and deep ocean currents; and the mechanisms of hurricane formation and the mixing of the troposphere and stratosphere.
Activation Analysis is also a use of nuclear chemistry. With the help of activation analysis (NAA) using the tracers, the composition of a valuable object or a very small sample could be determined. This method of nuclear chemistry even helps forensic chemists to detect traces and type of ammunition on a suspect’s hand or traces of arsenic in the hair of a victim of poisoning (Silberberg, 1065). This NAA technique of nuclear chemistry was also incorporated by the space scientists of NASA in the Sojourner robot vehicle to analyze the composition of Martian soils and rocks.
Sojourner heading towards yogi (Mars Robot)
This technique is also employed by automotive engineers to measure friction, and wear and tear of moving parts, such as piston rings. The radioactivity appearing in a lubricant placed between the surfaces can demonstrate the lubricant’s ability to reduce wear (Silberberg, 1066).
Medicine has significantly advanced with the use of nuclear chemistry. In fact the largest use of radioisotopes has been in medical science. “Over 25 percent of U.S. hospitals admissions are made for diagnoses based on data from radioisotopes (Silberberg, 1066).” Tracers are also employed to observe specific organs and body parts like brain, heart, thyroid, liver, lungs, circulatory system, eyes, tumors, heart muscles, general metabolism and also the physiological processes of blood flow.
The use of radioisotopes to image the thyroid gland (Silberberg, 1066)
With the help of nuclear chemistry, using the Positron-emission topography (PET) method observing the brain structure and functions is possible. “A biological substance is synthesized with one of its atoms replaced by an isotope that emits positrons. The substance is injected into a patient’s bloodstream, from which it is taken up into the brain. The isotope emits positrons, each of which annihilates a nearby electron (Silberberg, 1066).”
PET and brain activity : Using radioactive substances these scans can show brain activity from
musical stimulations.
In the field of medicine, applications of ionizing radiation can also be applied. A known fact about cancer is that the cancer cells divide more rapidly than normal cells. Radioisotopes could be used to damage the cell-division process by killing more cancer cells, to destroy pituitary and breast tumor cells and also to destroy brain tumors. Ionizing radiation is also used to control harmful insects. “Captured males are sterilized by radiation and released to mate, thereby reducing the number of offspring. This method has been used to control the Mediterranean malarial mosquito, in other parts of the world (Silberberg, 1067).” Nuclear energy can be used to help in the medical field and also has its long-term advantages in supplying for society’s future energy needs.
Scientists are having trouble learning how to control the reaction in a contained space. The advantage to nuclear fusion is that it creates less radioactive material than fusion and its supply of fuel can last longer than the sun. In the future, fossil fuels will be depleted, which we used today as a source of energy for everyday life. We have seen nuclear energy take its place as a major source of electricity worldwide.
Throughout the years, nuclear power has become an important commodity for many countries around the world. The parts of the world that utilize this valuable resource include European and Asian countries. Electric power has been by far the most beneficial of nuclear energy. Almost all of the world’s electric energy is produced by hydroelectric and thermal power plants. Most of the thermal plants operate by uranium fission, instead of using the force of the steam from boiling water. Nuclear energy has taken its place as a major source of electricity worldwide. “Nuclear energy now provides over 16 percent of the world’s total electricity. It has the potential to contribute much more, especially if greenhouse concerns lead to a change in the relative economic advantage of nuclear electricity, or its ethical desirability (Colvill, 2).” Most of the electricity of many countries is generated by nuclear power. France generates 79 percent of electricity with nuclear power, Belgium, 60 percent; Sweden, 42 percent; Switzerland, 39 percent; Spain, 37 percent; Japan, 34 percent; the UK, 21 percent; and the US, 20 percent. More than 434 nuclear power reactors operated in over 30 countries in the mid-1990’s, producing less than 20 percent of the world’s electricity (Bodansky 331). Canada produced about 15 percent of its power. The United States operated approximately 110 nuclear reactors, thereby making it the world’s largest producer of nuclear energy. Understanding the need for nuclear power as a means of generating electricity in a better way, South Korea and China also have announced plans to expand their nuclear-power capabilities by building 16 new nuclear plants. Although there was a reduction in the number of power plants, the United States’ nuclear industry generated 9 percent more nuclear electricity in 1999 than in 1998. With all these advances in nuclear power technology, nuclear power is meeting the annual electrical needs of more than a billion people worldwide. Concentrated nuclear power is clearly an alternative for generating electricity, and as the following examples illustrate, it is highly successful.
Of all the countries in the world, France is by far the most abundant in terms of nuclear power usage. Since 1986, over 70 percent of all electrical power is supplied in nuclear form within France (Bodansky, 330). 1993 was a pivotal year for France in terms of nuclear power usage. By that year, France’s total nuclear energy supply was 40 percent, with nuclear power supplying 73 percent of the country’s electricity (Bodansky, 331). This had also become the most dominant energy source in France for that year. France resorted to using nuclear energy as their main source of power for several reasons. The majority of the world’s energy comes from fossil fuels, which are quickly being depleted. Since France has only small amounts of fossil fuels available, nuclear energy has become a viable option to reduce the need to rely on coal and oil resources. There is also very mild legal opposition to the use of nuclear energy in France. The courts in France do not exercise strong authority upon the French decisions to harness nuclear power as their main source of energy. The French Communist party is also in favor of the use of nuclear power, while the other European countries, which included the left-winged political parties, were opposed to its use (Bodansky, 331). Lastly, politically speaking, the importance of nuclear energy has become a major political and national pride issue, since the nuclear program itself is so successful (Bodansky, 332).
In addition to France, Japan also has utilized nuclear energy as its main fuel supply. Considering Japan’s size and location, it acquires almost all fossil fuel energy through imports from other countries. Nuclear energy thus has become a convenient and practical fuel resource for the country. As a result, nuclear energy and hydroelectric power have become the chief domestic resources in Japan (Bodansky, 333). As in France’s situation, 1993 was a threshold for Japan, where nuclear power comprised 77 percent of Japan’s energy production (Bodansky, 333). Japan’s long-term goal is to have less dependence on other countries for its fuel supply. The recent surge in nuclear energy has been the impetus for Japan’s movement towards independence.
Affirming the growth of nuclear power in Japan, in October 1990, 40 nuclear power plants were planned for construction by the year 2010, thereby doubling the current number of reactors and increasing the power’s share of electricity generation to 43 percent [15, p. 5] (Bodansky, 333). Japan clearly has placed nuclear energy as its primary fuel, and continues to gain greater independence by using nuclear fuel instead of exporting scarce fossil fuels. In addition to Japan and France, other countries have accessed nuclear energy for various purposes.
The Former Soviet Union has continued to be well equipped industrially with nuclear energy. Russia has enough compatibility to build upon its already numerous nuclear resources. Within Russia, Ukraine allowed six nuclear power reactors to be put into operation between 1987 and 1989, before Ukraine separated from Russia. For Ukraine, the use of nuclear power has been in the background, and as for all of Russia, nuclear power remains an option for energy.
Eastern European countries have also viewed nuclear energy as an alternative to fossil fuel energy. The burning of fossil fuels, such as coal burning, causes major air pollution. This pollution has been highly problematic in many Eastern European countries; thus the use of nuclear power is a highly attractive option. In 1994, the total amount of energy derived from nuclear power was 76 percent in Lithuania, 49 percent in Slovak Republic, 44 percent in Hungary, and 46 percent in Bulgaria (Bodansky, 335). The Former Czechoslovakia received assistance from the West, France, Germany, and the United Kingdom in upgrading the reactor operations while continuing construction. In addition, the United States assisted in building two Czech nuclear reactors (Bodansky, 335). Lithuania also utilized nuclear electricity, and in 1994 was the most dependent on nuclear electricity, obtaining 76 percent of its electricity from reactors that operated in 1985 and 1987 (Bodansky, 335). Sweden also uses nuclear power for its energy source and currently gets almost half the electricity from nuclear energy. It is also the first country to have a widely accepted and effective program for disposal of nuclear fuel (Bodansky, 336).
The countries of Belgium and Switzerland received large portions of electricity from nuclear energy in 1994 while the Netherlands received a negligible amount (Bodansky, 336). In addition to the countries of Western Europe, countries in the Western Hemisphere have also been employing nuclear power.
Canada is an energy-rich country where the use for electricity varies throughout the country. Canada, in 1992 and 1993 had finished expanding its nuclear facilities, which allowed it to become a leader in terms of its nuclear capacity and generation. “British Columbia, Manitoba and Quebec use large hydro electric resources to generate electricity, as does Ontario. Coal is used in the Prairie and Atlantic Provinces, though to a lesser extent than in most developed countries. Ontario has made a major commitment to nuclear energy and depends on this for over 60 percent of its electricity. Quebec and New Brunswick also use nuclear energy (Bodansky, 336).” Small nuclear reactor programs also exist in Argentina, Brazil, and Mexico. There are additional Asian countries that also benefit from the use of nuclear energy.
Two other Asian countries besides Japan use nuclear energy for their electricity. Both South Korea and Taiwan have nuclear programs already in place. South Korea in particular, has a strong program, and in 1994 it had plans to develop seven nuclear reactors with an already existing nine nuclear reactors (Bodansky, 336). Additionally, plans to build four more with a long-term goal of gaining “nuclear technology self-reliance (Bodansky, 336).” South Korea has experienced success with nuclear energy, and also joins Taiwan in implementing nuclear programs. Taiwan began using nuclear power at an early stage, and in 1985, six reactors were being operated. By 1992, government officials opted to add two more nuclear reactors (Bodansky, 336). This latest plan for development is still in progress, yet Taiwan has joined Japan and South Korea in using nuclear power.
Both India and Pakistan are also using nuclear power programs, which are very small considering their size. India’s program is slightly larger than Pakistan’s program. Major roadblocks to the expansion of nuclear programs in these areas consist of high capital expense for nuclear reactors and hesitancy of other countries to go into cooperative agreements, since India and Pakistan have not accepted safety provisions for their nuclear programs (Bodansky, 337). Progress is being made slowly within the two countries; nonetheless, nuclear power is being utilized at a rapid rate. Lastly, China began using nuclear power in the mid-1990. By 1994, three nuclear reactors were operating. The demand for nuclear energy arose since the pollution from coal burning has become a serious problem as its economy has grown (Bodansky, 337). Current negotiations for nuclear supply have been made with France, Russia, South Korea, and Canada, which may be the start for a significant nuclear expansion (Bodansky, 337). Asia as a whole has embarked on the advantages of nuclear power, and as one Japanese scientist notes, it can provide for a promising future for Asian countries. “Nuclear power generation in this region will soon reach the level of Organization for Economic Cooperation and Development’s (OECD) European and North American regions. This is a striking example of the general shift in the world’s energy pattern from the traditionally developed countries of the OECD to other parts of the world…with the increasing importance of nuclear power in this part of the world, the future may development of this energy source may no longer be spearheaded by the traditionally developed countries of Europe and North America [30, p. 20], (Bodansky, 337).”
As we begin to see the effects of global warming occur, and the prices of fossil fuels increasing while its availability decreases, nuclear power continues to be an attractive alternative energy source. Many countries have already employed nuclear energy to generate their electricity, heating, and general energy uses, and benefited greatly from it. Nuclear reactor power plants continue to be built and the concept of nuclear energy is quickly becoming more common throughout the European, Asian, and North American continents. With the many advantages to nuclear energy, both economic and chemical efficiency, it is no surprise nuclear power has become so highly regarded for its many attributes. Nuclear power in this regard continues to remain a highly acceptable alternative to fossil fuels.