Energy in Agriculture: Energy Resource Series for Youth and Adult Energy Programs: 8
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University of Kentucky UKnowledge Agricultural Engineering Energy Series Biosystems and Agricultural Engineering 11-1981 Energy in Agriculture: Energy Resource Series for Youth and Adult Energy Programs: 8. Nuclear Fusion George M. Turner University of Kentucky Right click to open a feedback form in a new tab to let us know how this document benefits oy u. Follow this and additional works at: https://uknowledge.uky.edu/aees_reports Part of the Bioresource and Agricultural Engineering Commons Repository Citation Turner, George M., "Energy in Agriculture: Energy Resource Series for Youth and Adult Energy Programs: 8. Nuclear Fusion" (1981). Agricultural Engineering Energy Series. 16. https://uknowledge.uky.edu/aees_reports/16 This Report is brought to you for free and open access by the Biosystems and Agricultural Engineering at UKnowledge. It has been accepted for inclusion in Agricultural Engineering Energy Series by an authorized administrator of UKnowledge. For more information, please contact [email protected]. AEES-28 EnergyResource Series for Youth and Adult EnergyPrograms 8. NuclearFusion by GeorgeM. Turner ExtensionSpecialist for AgriculturalEngineering Departmentof AgriculturalEngineering Universityof Kentucky Lexington,Kentucky t v !.t UNIVERSITYof KENTUCKY in KENTUCKY COLLEGEof AGRICULTURE cooperolion DEPARTMENT OEPT.of AGRIC.ENGINEERING with of COOPERATIVEEXTENSION SERI/ICE ENERGY Preface The subjectof nuclearenergy can be dividedinto two parts,fission and fusion.The purposeof this publicationis to describethe processof nuclearfusion. Fusionof atomicnuclei offers tremendous possibility of energy.Since all forecasts point towarda needfor moreenergy in thiscountry, this method of energyproduction can provide a significantshare. At the presenttime we do not knowfor certainthat energy from the f usionprocess will be scientificallyand economicallysuccessful. lt is certainthat much researchwill continueto take place;if f usioncan be achieved,the promiseof the vastpower possible will be worththe effort. Beforeusing this publication, it isstrongly suggested that you study the first 14 pages of AEES-27,Nuclear Fission, since you will needto befamiliar with the force f ieldsprevalent in the nucleusin orderto understandthe fusionprocess. Thisis the eighth publication in a 12-partenergy resource series designed for the adult and studentwith a seriousinterest in the energysituation. Each publication in the series examinesa differentsource of energy and considersthe advantagesand disadvantages associatedwith its use. When necessary,diagrams and/or tables are used to clarify or elaborate upon informationfound in the text. Questionswith answersare includedat the end of each publicationso that you can testwhat you havelearned. The authorwishes to thank JosephTaraba and Linda Bach of the Departmentof AgriculturalEngineering, University of Kentucky,for reviewingthe text. The EnergyResource Series for Youthand Adult EnergyPrograms includes the following publications: AEES-21 EnergyOverview AEES-22 Definitions AEES-23 Oil and Gas AEES-24 Coal AEES-25 Solar AEES-26 Wind AEES-27 NuclearFission AEES-28 NuclearFusion AEES-29 Wood AEES-30 Water AEES-31 Geothermal AEES-32 Alcohol Contents Page Matterfnto Energy ...... 4 A Lookat Hydrogen..... ...... 5 SpeedingUp the Particles .. .. 6 Fusingthe Particles .. .. ....... 7 Mini-Voltages.... ....... 8 FuelReserves.... ....... I HarnessingFusion .. ... I The Needfor ContainersWithout Walls . .. ... I DesigningTo Fitthe Theory ........ 10 ContinuousFusion Method ..... 10 PulsedFusionSystem ..;... ....11 OtherMethods ..... 12 EnvironmentalEffects .... .... 12 FuelSources..... ...... 12 Questions .. .. .. 13 Answers ... 14 EnergyResource Series for Youth andAdult Energy Programs 8. Nuclear Fusion Matterinto Energy In AEES-27,Nuclear Fission, the electrostatic and internucleonforce f ieldswere described. lt was explainedthat the assemblednucleus has less mass than the sum of the individualnucleons making it up (Figure1). This loss of mass is turned into energyaccording to the law E = mc2and is the C sourceof nuclearenergy. The curve in Figure2 s showsthe averagemass loss per nucleonfor each z elementafter recombining. l z c 9 = c a Fig. 2.-Loss of nucleonmass when separatenucleons combine to form the nucleusof variouselements. The greaterthe lossper nucleonthe greaterthe energygiven up. The greaterthe vertical distancefrom one elementto another,the greaterthe lossol Flg.1,-Combining makesthe difference.This illustrationde- massper nucleon. picts what happenswhen separatenucleons, the particlesthat makeup the nucleus,whether proton or neutrons,combine to form the nucleus of a more complex element.The arrows It is important to realize that two types of representenergy given off equalto the lossin mass.The massof nuclearreactions are possible,occurring at oppo- the four particlesis greaterwhile separatethan afterthey have siteends of thiscurve. In AEES-27, Nuclear Fission, fusedinto one nucleus. the breakupor splittingof a largenucleus to form smallerones was described.This is what happens The massloss is great (notethe steepslope of on the right end of the curve.The subject of this the curve)for the lighterelements, that is, up to publicationis f usion or thecombining of lightnuclei about Ca, atomic number20; then the massloss intoheavier or morecomplex ones. This happens on levelsoff forthe mediumelements, f rom aboutFe to the left end of the curve.In both typesof reactions Pd. The graph indicatesa more gradualloss per the massof the productsis lessthan the massof the nucleonthrough the heavierelements up to Pu, original.lt is this differenceor lossof massthat atomicnumber 94. providesthe releaseof energy. Noticeon the rightend of thecurve that when a in presentnuclear energy plants. These fuels and heavynucleus is split, the end products,such as Kr their reactionsare describedin detailin AEES-27, and Ba from uranium,are at a higher vertical NuclearFission. positionon the curvethan the originalelement, U. In orderfor the lighterelements on the leftend Thisindicates that each nucleon making up the f inal of curve to move upward on the curve they must productshas less massthan when the nucleons combine,forming heavier elements. The combinai wereall togetherin the largenucleus of uranium. tion beinglooked at mostintensely is hydrogen(H) Thisis illustratedin Figure3A. fusingto form helium(He). The processof fusion that takes place on the left end of the curve is A illustratedin Figure38. The four particles(two Splittingof uraniumcan givekrypton and barium protonsand two neutrons)coming together to form helium have a greatermass as separateparticles than after they are forced together to form the helium nucleus.As can be seen on the curve,a relativelygreat vertical distance lies between H and e--_)@.@ He. This indicatesa much greater potentialfor energy releasethan on the f latterright end of the curve. 234.95255amu -) 83.78025amu + 137.30928amu + Energy 234.95255amu of assemblednucleus (by tests) -13.11258 amu of 13neutrons expelled to space A Look at Hydrogen 221.83997 amu of originalmass rejoined in Kr and Ba Hydrogenexists with a single proton as its = MassDifference 221.83997 amu of originalmass rejoined theproton will have a neutron in Kr and Ba nucleus.Occasionally -221.08953amu of the two new elements attached.This is stillthe hydrogen element because or products of the singleproton. However, it is twice as heavy o.75044 becauseof the two particlesin the nucleus.lt is with a capitalD The0.75044 amu loss of masshas been turned into energy. calledhydrogen-two or deuterium as the symbol.Sometimes the symbolH2 is used B whileH1 is used for hydrogenwith the single proton as the nucleus.About one atom in each 6,000 Fourseparate particles give helium. hydrogenatoms is H2. -6oo Hydrogen also exists with two neutrons at- @Io tachedto the protong iving a totalof three particles t9 in the nucleus.This isotopeis calledtritium (T) or "l - proton = 1.00728amu as separateparticle 1 - proton = 1.00728amu as separateparticle H3.Tritium is extremelyrare in naturebut does '1 - neutron = 1.00866amu as separateparticle occurin H2reactions for a verybrief time. lt canalso 1 - neutron = 1.00866amu as separateparticle beobtained by the bombardment of lithium(Li) with Total = 4.03188amu as separateparticle neutrons.These elements are illustrated in Figure4. MassDifference = 4.03188amu as separateparticle Theoretically,to obtainhelium from hydrogen, -4.0026 amu of assemblednucleus two hydrogennuclei must be movingtoward each 0.02928 otherwith highvelocity. Their kinetic energy must The 0.02928amu lossof masshas beenturned into energy. be greatenough to keepthem moving toward each other despitethe fact that their mutual positive Fig. 3.-Products haveless mass than the originalwhether f rom chargesare attempting to slowthem down and push fission ol uraniuminto krypton and barium (Fig. 3A) or fusion of them apart.Two protonsat two diametersapart hydrogentwo intohelium (Fig. 38). extenda repulsiveforce of 0.13 pounds.lf they come at each other with sufficientvelocity and Theoretically,any of the elementsfrom the amplekinetic energy to overcomethe electrostatic heavyend of the curvewould emit energy if split.In repulsionforce field, the stronginternucleon force practiceit hasbeen f ound that only U235 and P244 will fields interact and hold the two nucleitogether. The easilyfission. These are the elementsused as fuel necessaryrelative velocity has been calculatedto beabout 18 million mph. - -o\ .z- I \ Hydrogen-one(Hr)