Chapter E Nuclear Reactors

《Chapter E Nuclear Reactors》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。

1、ENuclearReactorsE.1PWR:Loss-of-CoolantAccidentE.1.1IntroductiontoLOCAAloss-of-coolantaccident(LOCA)occursasaresultofapenetrationtothemaincoolantboundarysuchthattheprimarycircuitwaterisreleasedthroughthebreaktothecontainmentarea,causingarapiddecreaseinthepressureandtemperatureoftheprimarycoolant.Thi

2、swillgiveanimpactthermalshockload.Thestreamlinebreakaccident(SLBA)occursasaresultofacompleteandpartialruptureofasteamlineinsidethecontainmentvessel.Arapidcool-downanddepressurizationoftheprimarycircuitnormallytakeplace.Inordertorestorethereactorcoolantpressure,apressureloadingunconnectedwithLOCAisr

3、equired.E.1.2DescriptionofthePWRVesselandItsMaterialsFigureE.1showsatypicalPWRvesselforSizewellB.Thevesselsteelmustpossesshightoughnessandstrengthcoupledwithadequateweldabilityinthicksections,withgenerallylow-alloysteelscontainingmanganese,nickelandmolybdenum.ThematerialgradeforplatesisSA-533Balloy

4、s,andSA-508alloysforforging.Bothmustbeinquenchedandtemperedconditions.Thesuitabilityofthesesteelsrestsonthemechanicalpropertiessuchasyieldstress,ultimatetensilestrength,elongationtofractureandcharpyimpactenergyaffectedbythermalaging,strainagingandneutronirradiation.Thevesselsaremadeoutofthick-sectio

5、nplatesofupto360mmorfromingotsofover200,000kg.Theingotsgenerallydevelopcavitiesofupto3mminthev-segregationregions.Thesearehealedbyhotworkingprocesses.Bothplatesandforgingsarewelded.FigureE.2showsvesselfabrications.TableE.1showsthedatausedinthethree-dimensionalfinite-elementanal-ysis.FiguresE.3andE.4

6、showthefinite-elementmeshgenerationscheme994ENuclearReactorscontrolroddrivemechanisminstrumentationposts-thermocouplesliftinglugcontrolroddriveshaftcontrolrodguidetuberodclustercontrolplateinternals(withdrawn)inletnozzlesupportledgeuppersupportdeepbeamweldmentcolumnoutletnozzlefuelassembliesuppercor

7、eplateformerreactorvessellowercoreplateirradiationspecimenbottomsupportguideforgingneutronshieldpadlowerinstrumentationradialsupportguidetubecoresupportcolumnstieplatesFig.E.1.Cut-awaydiagramshowingthePWRst