Word Count: 1748 by definition is the energyconsumed or produced in modifying thecomposition of the atomic nucleus. Nuclear energyis used for things such as atomic bombs, hydrogenbombs and other nuclear weapons.
Nuclearenergy can also be used for poweringelectricity-generating plants all over the world.There are many arguments for and against nuclearpower. Nuclear power is an inexpensive cleansource of power.
Others feel that because of thehazardous radiation emitted during the producingof the power and the radioactivity of the materialused that nuclear power is not as good as thealternatives which are fossil fuels and solarpower.(Hansen, 1993)If matter changes state or composition, it isaccompanied by the production of energy.Processes such as combustion produce energy byrearranging the atoms or molecules of thatsubstance.(Brain, 1998) An example of this is thecombustion of methane (natural gas) CH(4) + 2O(2) = CO(2) + 2H(2)O + energyIn this example the amount of energy released iseight electron volts or 8 eV. The electron volt unitis the unit used by nuclear physicists. The electronvolt represents the gain in kinetic energy when anelectron is accelerated through a potential drop ofone volt.(Brain, 1998)The most common nuclear reaction is nuclearfission.
Nuclear fission is the process in which aheavy nucleus combines with a neutron andseparates the heavy nucleus into two lighternuclei.(Roy, 1993) The most typical fissionreaction is that of uranium-235 it is as follows:92 U235 + 1 neutron = 38 Sr96 + 54 XE138 + 2neutrons + energyAnother type of nuclear reaction is nuclear fusion.Nuclear fusion occurs when two light elementscombine to form a heavier atom.(Grisham, 1993)An example of this is:1 H(2) + 1 H(3) = 2 He(4) +1 neutron + energyNuclear FissionNuclear fission is a complex process, but manyproducts are formed during this process. Not onlythe two nuclei but also neutrons, beta particles,neutrinos and gamma rays are created during thefission process.
(Roy, 1993) There are more thanfifty different ways a nucleus may undergo fission.Some of the ways are much more common thanothers. During the fission process the nucleusbreaks into to unequal parts, one lighter fragmentand a heavier fragment. These nuclei are formedwith excess energy that they do not usually have intheir ground state they must lose the extra energy.They release this extra energy in the form ofgamma radiation or sometimes neutron emission.The primary fragments are rich in neutrons and areradioactive. Uranium-235 which contains 92protons and 143 neutrons are more likely to undergo fission when bombarded by low-energyneutrons.(Hansen, 1993)Nuclear Fission Used in BombsThe fission process was discovered in the late1930s.
In late 1939 two scientists Otto Frisch andLise Meitner discovered the fissioning of uraniuminto lighter particles while they were doing anexperiment involving neutron irradiation ofuranium. The possibility of a self-sustaining chainreaction was apparent this caused an acceleratedrate of research.(Hansen, 1993)The United States Government researched into thepossible applications of nuclear fission at thebeginning of World War II. In order for theweapon to be able to work properly it wouldrequire a self-sustaining fission reaction to becreated and also that an adequate amount offissionable material could be produced for use in aweapon.(Brain, 1998) On December 2, 1942 atthe University of Chicago Enrico Fermi and histeam developed the worlds first self-sustainingreactors.
The reactor was fueled with naturaluranium imbedded in graphite blocks.(Hansen,1993) The fission occurred in the isotope ofuranium, U-235. An important factor indeveloping the nuclear bomb was to separateU-235 from U-238. Natural uranium only contains0.7% of U-235 and the remaining 99.3% ofnatural uranium is U-238. The problem with this isthat U-238 does not fission except with very highenergy neutrons which are not available from thefission process. To separate the two materialsgaseous defusion is used.
Another way of makingnuclear weapons is to use a different fissionablenucleus. Another material that is used is a syntheticisotope of plutonium P-239. Nuclear FusionIn most fusion reactions after the two atomic nucleimerge together to form a heavier nucleus a freenucleon is also formed. In just about all fusionreactions between light nuclei, a portion of theirrest mass is converted into kinetic energy of thereaction products, or into gamma rays.(Grisham,1993) The kinetic energy and gamma rays that arereleased in the process of fusion, heat the insidekeeping the temperature very high so the fusioncan continue occurring. At thermonucleartemperatures, matter can only exist in the plasmastate. Matter at thermonuclear temperatureconsists of electrons, positive ions and very fewneutral atoms.
If fusion reactions occur withinplasma the reactions heat the substance evenmore, because a portion of the reaction energy istransferred to the bulk of the plasma throughcollisions.(Grisham, 1993)Stars produce their energy through many types offusion reactions. Scientists know that fusionreactions have clear potential as a power sourceon earth due to the fact those fusion reactions havebeen driving the stars for billions of years.
(Hansen,1993) For many decades now scientists have triedto develop thermonuclear fusion reactions that willproduce useful power.Nuclear Waste Nuclear waste is one the biggest down fall tonuclear power. Nuclear waste is any radioactivematerial that is created by nucleartechnology.(www.hydro.
on.ca, 1999) The mostcommon form of nuclear waste is those that areproduced by civilian nuclear industry and thenuclear weapons program.There are many other sources of nuclear waste tosome of them are radioactive material that isproduced by medical research, research onnuclear power, industrial applications and thecontaminated sections of dismantled nuclearfacilities. Radioactive material decays by differentforms of radiation. Two different forms ofradiation are gamma rays and alpha particles.
Thedecay of the nuclear waste is characterized by thetype of emission, the energy of the emittedradiation, and the rate at which decay occurs. Thedecay rate of a radioactive material is usuallymeasured in terms of the half-life. A half-life is thetime that is required for one-half of the radioactivematerial to decay.(Brain, 1998) The half-life ofeach radioactive material is different, a half-life canrange from less than a millionth of a second tobillions of years.The danger of radioactive material is that theemitted radiation may come in contact with thehuman body and cause damage to cells. Theeffects of exposure to radioactive material canvary from mild, which is temporary illness todeath.
The effects of exposure can occurimmediately or can be delayed depending uponthe amount of radiation received.(Hansen, 1993)There are many different types of nuclear waste.Nuclear waste is normally characterized by itphysical and chemical properties and also theirsource of origin. For example is the United Statesall waste from the nuclear defense program isclassed as military waste and is usually treatedseparately. ChernobylChernobyl is a Soviet Union nuclear power plantthat is located about 130 km north of Kiev inUkraine. At the Chernobyl nuclear power plantoccurred the worlds worst nuclear-reactordisaster on April 26, 1986. On this day the powerplants number 4 reactors exploded. The accidentoccurred while an experiment was beingconducted with the graphite-moderated reactorrunning but its emergency water-cooling systemturned off.
The nuclear reactor suddenly went outof control because of some miscalculationsallowed a neutron build-up in the core. The powersurge shattered the fuel. A steam-inducedexplosion blew the lid off of the reactor becausethe reactor was not designed for such pressure.Another chemical explosion followed andscattered fragments around the plant causing localfires.(Grolier, 1993)This nuclear killed 31 persons either immediatelyor shortly thereafter, the nuclear blast also causedthe hospitalization of 500 others. People livingwithin 30 km of the power plant were evacuatedwithin a few days of the blast. Much of theradioactivity was carried away from the site at highaltitudes due to the explosions and the fire.(Brain,1998) The radioactivity was spread across theNorthern Hemisphere.
The heaviest of theradioactivity descended upon western SovietUnion and some of Europe. These areas tookpreventive steps to protect their food supplies.The data on the effects of the radioactivity on theworld remain inconclusive. The area within 30 km of the power plantsremoved the heavily contaminated soil and trees totry and get rid of any nuclear waste left there. In1990 the authorities acknowledged that severalmillion people were still living on contaminatedground. Illnesses such as thyroid cancer, leukemiaand other radiation illnesses are much higher thannormal among these people living on contaminatedground. At the plant reactor number 4 wasentombed in concrete.
Two of the three reactorsat Chernobyl are still in operation. There havebeen other accidents since reactor number 4 blewup because of this Ukraines Parliament in 1991pressed for a complete shut down of the plant.This idea is highly unlikely because it is the onlypower source for the region.
(Hansen, 1993)Nuclear Energy TodayNuclear power has become a major source of theworlds electric energy since the discovery offission 50 years ago. At the end of 1989 therewere 416 nuclear power plants operatingworldwide producing 17% of the worldselectricity. There were 130 plants that were underdesign at the end of 1989. Nuclear power is usedin 27 different nations and another three nationshave plants under construction. The United Stateshas the worlds largest nuclear energy program atthe end of 1989 with 108 operating plants havingthe operating capacity of 100,000 MW providing20% of the U.S. with their power.
In 1989 nuclearpower was the second largest source of electricityin the U.S. exceeded only by coal whichcontributes 55% of the U.S.s electricity. Othersources of power are natural gas 9%, oil 6%, andhydro power 9%.(Hansen, 1993) In Ontario 40%of the electricity that is used is produced bynuclear power. Ontario nuclear power plantsproduce 8728 MW ofelectricity.
(www.hydro.on.ca, 1999)Nuclear power plants are more complex and costmore to build than plants that use fossil fuels. Thecost of fuel for nuclear power is much lower thanthe cost of fossil fuel. In the long run nuclearelectricity is much cheaper for most nationsbecause of the differences in fuel prices.
Forindustrialized countries of Europe and Asia thedifference in cost may be as large as a factor ofhalf the cost. In some countries the nuclear powerprogram has come to a standstill. In the UnitedStates there hasnt been an order to build anuclear power plant since mid-1970’s. The mainreason for the standstill is the move towardsincreased efficiency in the consumption of oil andalso a drop in the demand for energy. The publicis also concerned about the safety of nuclearpower plants and also the increasing awareness ofthe problems with nuclear waste.
The reason forthe increase in safety awareness is because of theaccidents that have occurred. Before 1979 thepublic was all for nuclear energy but since then areactor in Three Mile Island leaked radioactivematerial into the environment. The largest reasonwhy the public changed their view was theexplosion of reactor four at the Chernobyl powerplant. Nuclear power is an important factor in all of arelives, if it if used safely it provides us withinexpensive electricity but if used carelessly it canmake us ill, destroy the land and even kill us. It isbelieved that in the future nuclear power will besafer for all. The pro and cons of nuclear powerare balanced because it is much more inexpensiveand it will not run out like fossil fuels eventuallywill. Nuclear reactors do not explode all thatoften.