核电站的腐蚀(英文)

LiAPPENDIXLELECTRICALUTILITIESLiiLiiiAPPENDIXLELECTRICALUTILITIESGERHARDUSH.KOCHPH.D.1SUMMARYANDANALYSISOFRESULTSCorrosionControlandPreventionThetotalcostofelectricitysoldintheUnitedStatesin1998was3.24milliongigawatthours(GWh)atacosttoconsumersof$218.4billion.Electricitygenerationplantscanbedividedintosevengenerictypes:fossilfuel,nuclear,hydroelectric,cogeneration,geothermal,solar,andwind.ThemajorityofelectricpowerintheUnitedStatesisgeneratedbyfossilandnuclearsteamsupplysystems.Thefossilfuelsector(includinggasturbinesandcombinedcycleplants)isthelargest,withageneratingcapacityofapproximately488gigawatts(GW),andatotalgenerationof2.227millionGWhin1998.In1998,approximately102nuclearstationswereoperation,withageneratingcapacityof97.1GWandatotalgenerationof673,700GWh.TwodifferenttypesofnuclearreactorsarecurrentlyinuseintheUnitedStates,namelytheboilingwaterreactor(BWR)andthepressurizedwaterreactor(PWR).Thefuelforthesetypesofreactorsissimilar,consistingoflongbundlesof2to4percentenricheduraniumdioxidefuelpelletsstackedinzirconium-alloycladdingtubes.TheBWRdesignconsistsofasingleloopinwhichtheenteringwateristurneddirectlytosteamfortheproductionofenergy.ThePWRdesignisatwo-loopsystemthatuseshighpressuretomaintainanall-liquid-waterprimaryloop.Energyistransferredtothesecondarysteamloopthroughtwotofoursteamgenerators.ThePWRalsousesawetsteamturbine.Theelectricpowerindustryusesthreedifferenttypesoffossilfuelpowerplants.Themostcommonandwidelyusedisthepulverizedcoal-firedsteampowerplant.Fueloilcanbeusedinsteadofcoal.Gasturbinesareusuallysmallerunitsthatareusedforpeakloadsandoperateonlyforafewhoursperday.Combined-cycleplantsusingbothsteamandgasturbinesaregenerallyusedforbaseloadservice,butalsomustbecapableofaddressingpeakloads.Hydraulicpowersystemsincludebothhydroelectricandpumpedstoragehydroelectricplants.Inbothprocesses,waterisdirectedfromadamthroughaseriesoftaperingpipestorotateturbinesthatcreateelectricity.Inprinciple,thepotentialenergyheldinthedamconvertsintokineticenergywhenitflowsthroughthepipes.Theconceptbehindthedevelopmentofpumpedstorageplantsistheconversionofrelativelylow-cost,off-peakenergygeneratedinthethermalplantintohigh-value,on-peakpower.Waterispumpedfromalowertoahigherreservoirwhenlow-costpumpingisavailablefromlarge,efficientthermalplantgeneration.Itisreleasedduringperiodsofhighpowerdemandanddisplacestheuseofinefficient,costlyalternativesourcesofgeneration.Thetotalcostofelectricityof$218.4billioncanbedividedintooperationandmaintenance(O&M),depreciation,andforcedoutages.Thecorrosion-relatedcostofforcedoutagesinthenuclearpowerindustrywasestimatedat$670million.Thetotalcostofdepreciationbasedonthe1998FederalEnergyRegulatoryCommission(FERC)FormNo.1datawas$35.7billion.Basedonanevaluationofdepreciationbyfacilitytype,apercentageduetocorrosionwasestimated.Thiscostpercentageduetocorrosionaspartofthetotalutilitydepreciationin1998was9.73percentor$3.433billion,withnuclearfacilitiesat$1.546billion,fossilfuelfacilitiesat$1.214billion,transmissionanddistributionat$607million,andhydraulicandotherpowerat$66million.ThecorrosionportionoftheannualO&Mcostwasestimatedat$698millionforfossilfuel,$2.013billionfornuclearfacilities,and$75millionforhydraulicpower,foratotalof$2.786billion.Thus,thetotalcostofcorrosionintheelectricalutilitiesindustryin1998isestimatedat$6.889billionperyear.1CCTechnologiesLaboratories,Inc.,Dublin,Ohio.AppendixL–ElectricalUtilitiesLivAstudyfortheElectricPowerResearchInstitute(4)toestimatethecostofcorrosionforelectricalutilitiesestimatedthatthecostofcorrosiontoconsumersofelectricitywasapproximately$17.27billionperyear,whichrepresentsapproximately7.9percentofthetotalcostofelectricitytotheconsumersof$218.4billion.Thesignificantdifferenceinthedirectcostofcorrosiontotheutilitiesownersofabout$6.9billionandthecosttoconsumersofapproximately$17.27billioncanbeattributedtooverheadandmanagementcostsandtaxes.OpportunitiesforImprovementandBarrierstoProgressBecauseofthecomplexandoftencorrosiveenvironmentsinwhichpowerplantsoperate,corrosionhasbeenaseriousproblem,withasignificantimpactontheoperationoftheplants.Inthe1970sand1980s,majoreffortsweremadetounderstandandcontrolcorrosioninbothnuclearandfossilfuelsteamplants,andsignificantprogresswasmade.However,withtheagingofseveralplants,oldproblemspersistandnewonesappear.Forexample,corrosioncontinuestobeaproblemwithelectricalgeneratorsandturbines.Specifically,stresscorrosioncrackinginsteamgeneratorsinPWRplantsandboilertubefailuresinfossilfuelplantscontinuetobeproblems.Therearefurtherindicationsthatburiedstructures,suchasservicewaterpiping,starttoshowleaksthatcannotbetolerated.Environmentalrequirementsandderegulationofthepowerindustryoftenresultinlessattentionbeingpaidtocorrosionanddeteriorationofmaterialsofconstruction.Ifcorrosionissuesarenotaddressedinatimelymanner,thesematerialswillcorrodetothepointthatmajorrepairandrehabilitationwillberequired.Thecostofcorrosionwillthenincreasesignificantly.RecommendationsandImplementationItisrecommendedthateconomiccorrosioncontrolprogramstoprovid