RG1.056 沸水堆水纯净度的维护 1978

Revision1*July1978U.S.NUCLEARREGULATORYCOMMISSIONREGULATORYGUIDEOFFICEOFSTANDARDSDEVELOPMENTREGULATORYGUIDE1.56MAINTENANCEOFWATERPURITYINBOILINGWATERREACTORSA.INTRODUCTIONGeneralDesignCriteria14,ReactorCoolantPressureBoundary,and31,FracturePreventionofReactorCoolantPressureBoundary,ofAppendixA,GeneralDesignCriteriaforNuclearPowerPlants,to10CFRPart50,DomesticLicensingofProductionandUtilizationFacilities,requireassurancethatthereactorcoolantpressureboundarywillhaveminimalprobabilityofgrossruptureorrapidlypropagatingfailure.GeneralDesignCriterion15,ReactorCoolantSystemDesign,requiresthatthereactorcoolantsystemandassociatedauxiliary,control,andprotection'systemsbedesignedwithsufficientmargintoensurethatthedesignconditionsofthereactorcoolantpressureboundaryarenotexceededduringanyconditionofnormaloperation,includinganticioperationaloccurrences.Failureofthereactor0antpressureboundarymaybepostulatedwhethemechanismsofgeneralcorrosionandstrrrrcrackinginducedbyimpuritiesinthermctorclanarepresent.Furthermore,GeneralDesignCriterion-,InstrumentationandControlrequiresthatinstrumentationbeprovidedtovariablesandsystemsthatcanaffectthereacpressureboundaryovertheiranticirafonormaloperation,foranticipatedratIurrences,andforaccidentcondilpnsappriatetoensureadequatesafety.YThisgdescribesamethodacceptabletotheNRCstafff.mplementingthecriteriawithregardtominimizingtheprobabilityofcorrosion-inducedfailureofthereactorcoolantpressureboundaryin*Thesubstantialnumberofchangesinthisrevisionhasmadeitimpracticaltoindicatethechangeswithlinesinthemargin.boilingwaterreactors(BWRs)bymaintainingacceptablepuritylevelsinthereactorcoolant.ItfurtherdescribesinstrumentationacceptablejtheNRCstafffordeterminingtheconditionofreactorcoolantandcoolantpurificationsysteiS.B.DIWaterqualityrosduringconstructionwhenextensiveeenessarytoensurethatcomponentspeclean.Concernwithproperternmstartevenbeforetheplantoperate..nti~ethroughalloperationsuntilfinlshuaintenanceofhighwaterqualityisntngalloperationssincewaterisoftenmrafnonepartoftheplanttoanotherdur-tasandthiswatercaneasilyfinditswaytoheellandfromtheretothereactor.TnatypicalBWRdirectorsinglecyclereactorsystem(seeFig.1intheappendix),waterisboiledbymeansofanuclearfissionheatsource.Thesteamandwatermixtureproducedinthecoreareapassesthroughsteamseparatorswheremuchofthewaterisremoved.Wetsteampassesfromtheseparatorstothesteamdryerstoproducerelativelydrysteam(lessthan1/10ofapercentmoisture).Thesteamatapproximately1000psiand550'F(288°C)entersthemainsteamlinesandpassesthroughtheturbinetothemaincondenser.Condensedsteamiscollectedinthehotwelllocatedbelowthecoolingtubesofthecondenser.Leaksinthecondensertubescanresultincirculatingwaterenteringthehotwellandintroducingimpurities.Whenthecirculatingwaterinthecondensersisseawater,theconsequencesoftubeleaksmaybequitesignificant;therefore,specialprecautionsarerequiredinseawater-cooledplants.De-aerationinthecondenserreducestheoxygencontentofthewater.ThecondensatethenpassesUSNRCREGULATORYGUIDESCommentsshouldbesenttotheSecretaryoftheCommission,US.NuclearReguRegulatoryGuidesareissuedtodescribeandmakeavailabletothepublicmethodslatoryCommission,Washington,D.C.20555.AttentionDocketingandServiceaccepltabletotheNRCstaffofimplementingspecificpartsoftheCommission'sBranch.regulations,todelineatetechniquesusedbythestaffinevaluatingspecificproblemsTheguidesareissuedinthelollowingtenbroaddivisionsonpostulatedaccidents,ortoprovideguidancetoapplicants.RegulatoryGuidesarenotsubstitutesforregulations,andcompliancewiththemisnotrequired.1.PowerReactors6.ProductsMethodsandsolutionsdifferentfromthosesetoutintheguideswillbeaccept-2.ResearchandTestReactors7.Transportationableiftheyprovideabasisforthefindingsrequisitetotheissuanceorcontinuance3.FuelsandMlterialsFacilities8.OccupationalHealthofapermitorlicensebytheCommission.4.EnvironmentalandSiting9.AntitrustReview5.MaterialsandPlantProtectiont0.GeneralCommentsandsuggestionsforimprovementsintheseguidesareencouragedatalltimes,andguideswillberevised,asappropriate,toaccommodatecommentsandRequestsforsinglecopiesofissuedguides(wlchmaybereproducedlorforplacetoreflectnewinformationorexperience.However,commentsonthisguideifmentonanautomaticdistributionlistforsinglecopiesoffutureguidesinspecificreceivedwithinabouttwomonthsafteritsissuance,willbeparticularlyusefulindivisionsshouldbemadeinwritingtotheUS.NuclearRegulatoryCommission.evaluatingtheneedforanearlyrevision.Washington,D.C.20555.Attention:Director.DivisionofDocumentControl.throughfull-flowdemineralizersinordertoobtainthepurestpossiblefeedwater.Thecondensatedemineralizersremoveinsolublecorrosionproductsbyfiltrationandremovedissolvedionicmaterials,i.e.,metalsandsalts,byionexchange.Theyalsoaffordlimitedprbtectionfromlargecondensertubeleaksuntilcorrectiveactionisinitiated.Thefeedwaterpassesthroughthefeedwaterheatersandentersthereactoratabout385°F(196°C).Sincethereisnoblowdown,thereactorwaterconcentratesallthesolubleandinsolublematerialsthatenterviathefeedwater.InBWRs,thereactorwatercleanupsystemperformstheblowdo