核电英语300句.docx

核电英语300句.docx

《核电英语300句.docx》由会员分享，可在线阅读，更多相关《核电英语300句.docx（13页珍藏版）》请在冰豆网上搜索。

核电英语300句

核电英语300句

UNIT1HIESTORYOFNUCLEARPOWER

1.Thediscoveryofnuclearfissionin1939wasaneventofepochalsignificancebecauseitopeneduptheprospectofentirelynewsourceofpower.

2.Theworld’sfirstself-sustainingnuclearfissionchainwasrealizedintheunitedstatesattheUniversityofChicago,2kWtCP-1,onDecember2,1942.

3.Aprototypeofthesubmarinereactor（calledSTRMark1）startedoperationatArco,Idaho,inMarch1953andthefirstnuclearpoweredsubmarinecommenceditsseatrialsinJanuary1955.

4.Theword’sfirstindustrynuclearpowerplant（5MW）wascommencedintheU.S.S.RonJune27,1954.

5.TheShippingPortPWR,thefirstcentral-stationnuclearpowerplantintheUnitedStates,wenttooperationonDecember2,1957.

6.A20MWnuclear-powerdemonstrationplantinCanadahasputinoperationsinceOctober1963andthefirstCANDUpowerreactorunitatDouglasPoint（200MW）reachedfullpoweroperationin1968.

7.Thefirstnuclearreactor（HWRR）inChinawentcriticalonJune13,1958andstartedpoweroperationonSeptember23,1958.

8.ThefirstatomicbombinChinawassuccessfullyexplodedonOctober16andthefirsthydrogenbombinChinaonJune17,1967.

9.ThefirstnuclearsubmarineinChinacommenceditsseatrialsonAugust23,1971.

10.The300MWeQNPC,designedandconstructedbyChina,wasconnectedtothegirdofelectricitygenerationonDecember,15,1991.

11.TheDayaBayNuclearPowerStationwasconnectedtothegirdonAugust31,1993andstartedcommercialoperationonFebruary1,1994.

12.InadditiontoQNPCandDayaBayNuclearPowerStation,othernuclearpowerplantsarebeingconstructedinChina.

UNIT2DEMANDFORELECTRCPOWER

1.      Duringthepresentcentury,theworld’sconsumptionofenergyhasgrownrapidlyduetothepercapitaincreaseintheuseofenergyforindustry,agricultureandtransportation.

2.      Itisofspecialinterest,thelargerandlargerproportionsoftheenergyusedareintheformofelectricpower.

3.      Thegenerationofelectricityrequiresprimaryenergysourcesandtheincreasingdemandforelectricpowercanbesatisfiedonlyifsuchprimarysourcesarerapidlyavailable.

4.      Themainenergysourcesforthegenerationofelectricityhavebeenthefossilfuels,i.e.,coal,naturalgas,oilandhydroelectric（water）power.

5.      Theadverseenvironmentaleffectsofstripminingandtheburningofcoal,aswellasincreasingcosts,aremakingcoallessattractiveforthegenerationofelectricity.

6.      Althoughnewreservesofoilandnaturalgasarebeingdiscovered,itappearsthattheworldwideproductionofthesefuelswillstarttodecreasearoundtheturnofthecentury.

7.      Coalandpetroleumprovidetheessentialrawmaterialsfortheproductionofchemicals,includingmedicinalproducts,dyes,fibers,rubberandplastics.

8.      Inthelongrun,thefossilfuelsmayprovetobemorevaluableintherespectofchemicalsproductionthanasprimarysourcesofenergy.

9.      Theideaofmakinguseofthesun’senergyisveryattractive,butconsiderableresearchanddevelopmentwillberequiredbeforeelectricitycanbegeneratedfromsolarenergyonacommercialscale.

10.  Nuclearenergycanbemadeavailableeitherbythefissionofheavyatomicnucleiorthefusionofverylightones.

11.  Thefusionprocesshasbeendemonstrated,bothinexperimentsandinthehydrogenbomb;butisdoubtful-thatfusionenergycanmakeanysignificantcontributiontothepowerrequirementsbeforetheendofthecentury.

12.  Nuclearfissionhasbeenestablishedasaprimarysourceofenergyatcoststhatar

UNIT3RADIOACITIVITY

1.    Anatomconsistsofapositivelychargednucleussurroundedbynegativelychargedelectrons,sothattheatomasawholeiselectricallyneutral.

2.   Atomicnucleiarecomposedoftwokindsoffundamentalparticles,namely,protonsandneutrons.

3.  Theprotoncarriesasingleunitpositivechargeequalinmagnitudetotheelectroniccharge.

4.   Theneutronisveryslightlyheavierthantheprotonandisanelectricallyneutralparticle.

5.   Foragivenelement,thenumberofprotonspresentintheatomicnucleusiscalledtheatomicnumberoftheelementandthetotalnumberofnucleons,i.e.,ofprotonsandneutronsiscalledthemassnumber.

6.   Thetermnuclideiscommonlyuseddescribeanatomicspecieswhosenucleihaveaspecifiedcomposition,thatistosay,anuclideinnatureisaspecieshavinggivenatomicandmassnumbers.

7.   Suchnuclides,havingthesameatomicnumberbutdifferentmassnumber,arecalledisotope,e.g.,threeformsofuraniumisotopesinnaturewiththeatomicnumber92butmassnumber234,235and238,respectively.

8. Theunstablesubstancesundergospontaneouschange,i.e.,radioactivedecay,atdefiniterates.

9. Theradioactivedecayisassociatedwiththeemissionfromtheatomicnucleusofanelectricallychargedparticle,eitheraalphaparticles,i.e.,heliumnucleus,orabetaparticles,i.e.,anelectron.

10.  Inmanyinstancesofgammarays,whicharepenetratingelectromagneticradiationofhighenergy,accompanytheparticleemission.

11.  Themostwidelyusedmethodforrepresentingtherateofradioactivedecayisbymeansofthehalf–life,whichisdefinedasthetimerequiredforthenumberofradioactivenucleitodecaytohalfitsinitialvalue.

12.  Sincethenumberofnuclei（ortheiractivity）decaystohalfitsinitialvalueinahalf-lifeperiod,thenumber（oractivity）willfalltoone-fourthbytheendoftwohalf-lifeperiods,andtolessthan1percentofitsinitialvalueaftersevenhalf-lifeperiods.

UNIT4NUCLEARFISSION

1.  Theneutron-nucleireactorsfallintothreegeneralcategories,namely,scattering,captureandfission.

2.  Afterabsorptionofaneutron,anucleusbreaksintotwolighternuclei,calledfissionfragments,withtheliberationofaconsiderableamountofenergyandtwoorthreeneutrons;thisphenomenoniscallednuclearfission.

3.   Itshouldbenotedthatitisonlywiththefissionnuclidesthataself-sustainingfissionchainispossible.

4. Uranium-233,Uranium-235,Uranium-239,whichwillundergofissionwithneutronofanyenergy,arereferredtoasfissionnuclides.

5.   Sincefissionofthorium-232anduranium-238ispossiblewithsufficientfastneutron,theyareknowsasfissionablenuclides;moreover,sincethorium-232anduranium-238canbeconvertedintothefissilenuclides,uranium-233andplutonium-239,respectively,theyarealsocalledfissilenuclides.

6. Thefissionofasingleuranium-235（orsimilar）isaccompaniedbythereleaseofover200MeVofenergy,withmaybecomparedabout4eVreleasedbythecombustionofanatomofcarbon-12.

7.   Theneutronscanstrikeotheruraniumatomsandcauseadditionalfissionandthecontinuingprocessoffissioningisknownasachainreactor.

8.  Sincetwoorthreeneutronsareliberatedineachoffissionwhereasonlyoneisrequiredtomaintainafissionchain,itwouldseemthatoncethefissionreactionwereinitiatedinagivenmassoffissilematerial,itwouldreadilysustainitself.

9.  However,suchisnotthecasebecausenotalltheneutronsproducedinfissionareavailabletocarryonthefissionchain,thatis,someneutronsarelostinnonfissionreactions（mainlyradioactivecapture）,whereasotherneutronsescapefromthesystemundergoingfission.

10.  Theminimumquantityofsuchmaterialthatiscapableofsustainingafissionchainiscalledthecriticalmass.

UNIT5GENERALFEATURESOFNECLEARREACTORS

1.Adeviceinwhichnuclearfissionenergyisreleasedinacontrolledmanneriscallednuclearreactor.

2.Inoutline,areactorconsistsofanactivecoreinwhichthefissionchainissustainedandinwhichmostoftheenergyoffissionisreleasedasheat.

3.Thecorecontainsthenuclearfuel,consistingofafissilenuclideandusuallyafertilematerialinaddition.

4.Thefunctionofthemoderatoristoslowdownthehigh-energyneutronsliberatedinthefissionreactor.

5.Thepurposeofreflectoristodecreasethelossofneutronsfromthecorebyscatteringbackmanyofthosewhichhaveescaped.

6.Theheatgeneratedinthereactorisremovedbycirculationofasuitablecoolant,suchasordinary（light）water,heavywater,liquidsodium（orsodium-potassiumalloy）,airandheliumetc.

7.Thehigherthetemperatureofthesteam,thegreatertheefficiencyforconversionintousefulpower.

8.Iftheenergyreleasedinthereactoristobeconvertedintoelectricpower,theheatmustbetransferredfromthecoolanttoaworkingfluidtoproducesteam.

9.Reactorcontrol,includingstartup,poweroperationandshutdownisgenerallybymovingcontrolrods.

10.Inmostcommercialthermalreactorsthefueliseitheruranium（0.7%uranium-235）,withheavywaterorgraphiteasthemoderator,oruraniumcontaining2-4percentofthefissileisotope,withordinarywaterasthemoderator.

11.Basedonthepurpose,thereactorcanfallintoexperimental（orresearch）reactor,productionreactor,powerreactor,dualpurpose（powerandproduction）reactorornuclearheatingreactor.

12.Accordingtothetypeofcoolantandmoderator,reactorcanbecalledpressurizedwaterreactor,boilingwaterreactor,heavywaterreactor（e.g.CANDU）,graphitereactor,orliquidmetalcooledreactor.

UNIT6REACTORCONTROL

1.Inthenormaloperationofareactor,thefunctionsofthecontrolsystemmaybedividedintothreephases,i.e.startup,poweroperationandshutdown.

2.Ifthepotentiallyunsafeconditionsshouldarise,aprotectionsystemwouldautomaticallyshutdownthereactor.

3.Anessentialrequirementofthecontrolsystemisthatitmustbecapableofintroducingenoughnegativereactivitytocompensate