TheFukushimaDaiichiIncident–Dr.MatthiasBraun-25January2020-p.1TheFukushimaDaiichiIncident–Dr.MatthiasBraun-25January2020-p.2TheFukushimaDaiichiIncident1.PlantDesign2.AccidentProgression3.Radiologicalreleases4.Spentfuelpools5.SourcesofInformationMatthiasBraunPEPA4-G,AREVA–NPGmbHMatthias.Braun@AREVA.comTheFukushimaDaiichiIncident–Dr.MatthiasBraun-25January2020-p.3TheFukushimaDaiichiIncident1.PlantDesignFukushimaDaiichi(PlantI)UnitI-GEMarkIBWR(439MW),Operatingsince1971UnitII-IV-GEMarkIBWR(760MW),Operatingsince1974TheFukushimaDaiichiIncident–Dr.MatthiasBraun-25January2020-p.4TheFukushimaDaiichiIncident1.PlantDesignnucleartourist.comen.wikipedia.org/wiki/Browns_Ferry_Nuclear_Power_PlantBuildingstructureConcreteBuildingSteel-framedServiceFloorContainmentPear-shapedDry-WellTorus-shapedWet-WellTheFukushimaDaiichiIncident–Dr.MatthiasBraun-25January2020-p.5TheFukushimaDaiichiIncident1.PlantDesignServiceFloorTheFukushimaDaiichiIncident–Dr.MatthiasBraun-25January2020-p.6TheFukushimaDaiichiIncident1.PlantDesignLiftingtheContainmentclosureheadTheFukushimaDaiichiIncident–Dr.MatthiasBraun-25January2020-p.7TheFukushimaDaiichiIncident1.PlantDesignReactorServiceFloor(SteelConstruction)ConcreteReactorBuilding(secondaryContainment)ReactorCoreReactorPressureVesselContainment(Drywell)Containment(WetWell)/CondensationChamberSpendFuelPoolFreshSteamlineMainFeedwaterTheFukushimaDaiichiIncident–Dr.MatthiasBraun-25January2020-p.8TheFukushimaDaiichiIncident2.Accidentprogression11.3.201114:46-EarthquakeMagnitude9PowergridinnorthernJapanfailsReactorsitselfaremainlyundamagedSCRAMPowergenerationduetoFissionofUraniumstopsHeatgenerationduetoradioactiveDecayofFissionProductsAfterScram~6%After1Day~1%After5Days~0.5%TheFukushimaDaiichiIncident–Dr.MatthiasBraun-25January2020-p.9TheFukushimaDaiichiIncident2.AccidentprogressionContainmentIsolationClosingofallnon-safetyrelatedPenetrationsofthecontainmentCutsoffMachinehallIfcontainmentisolationsucceeds,alargeearlyreleaseoffissionproductsishighlyunlikelyDieselgeneratorsstartEmergencyCorecoolingsystemsaresuppliedPlantisinastablesavestateTheFukushimaDaiichiIncident–Dr.MatthiasBraun-25January2020-p.10TheFukushimaDaiichiIncident2.Accidentprogression11.3.15:41TsunamihitstheplantPlantDesignforTsunamiheightofupto6.5mActualTsunamiheight7mFloodingofDieselGeneratorsand/orEssentialservicewaterbuildingcoolingthegeneratorsStationBlackoutCommoncausefailureofthepowersupplyOnlyBatteriesarestillavailableFailureofallbutoneEmergencycorecoolingsystemsTheFukushimaDaiichiIncident–Dr.MatthiasBraun-25January2020-p.11TheFukushimaDaiichiIncident2.AccidentprogressionReactorCoreIsolationPumpstillavailableSteamfromtheReactordrivesaTurbineSteamgetscondensedintheWet-WellTurbinedrivesaPumpWaterfromtheWet-WellgetspumpedinReactorNecessary:BatterypowerTemperatureinthewet-wellmustbebelow100°CAsthereisnoheatremovalfromthebuilding,theCoreisolationpumpcantworkinfinitelyTheFukushimaDaiichiIncident–Dr.MatthiasBraun-25January2020-p.12TheFukushimaDaiichiIncident2.AccidentprogressionReactorIsolationpumpstops11.3.16:36inUnit1(Batteriesempty)14.3.13:25inUnit2(Pumpfailure)13.3.2:44inUnit3(Batteriesempty)DecayHeatproducesstillsteaminReactorpressureVesselPressurerisingOpeningthesteamrelievevalvesDischargeSteamintotheWet-WellDescendingoftheLiquidLevelintheReactorpressurevesselTheFukushimaDaiichiIncident–Dr.MatthiasBraun-25January2020-p.13TheFukushimaDaiichiIncident2.AccidentprogressionReactorIsolationpumpstops11.3.16:36inUnit1(Batteriesempty)14.3.13:25inUnit2(Pumpfailure)13.3.2:44inUnit3(Batteriesempty)DecayHeatproducesstillsteaminReactorpressureVesselPressurerisingOpeningthesteamrelievevalvesDischargeSteamintotheWet-WellDescendingoftheLiquidLevelintheReactorpressurevesselTheFukushimaDaiichiIncident–Dr.MatthiasBraun-25January2020-p.14TheFukushimaDaiichiIncident2.AccidentprogressionReactorIsolationpumpstops11.3.16:36inUnit1(Batteriesempty)14.3.13:25inUnit2(Pumpfailure)13.3.2:44inUnit3(Batteriesempty)DecayHeatproducesstillsteaminReactorpressureVesselPressurerisingOpeningthesteamrelievevalvesDischargeSteamintotheWet-WellDescendingoftheLiquidLevelintheReactorpressurevesselTheFukushimaDaiichiIncident–Dr.MatthiasBraun-25January2020-p.15TheFukushimaDaiichiIncident2.AccidentprogressionReactorIsolationpumpstops11.3.16:36inUnit1(Batteriesempty)14.3.13:25inUnit2(Pumpfailure)13.3.2:44inUnit3(Batteriesempty)DecayHeatproducesstillsteaminReactorpressureVesselPressurerisingOpeningthesteamrelievevalvesDischargeSteamintotheWet-WellDescendingoftheLiquidLevelintheReactorpressurevesselTheFukushimaDaiichiIncident–Dr.MatthiasBraun-25January2020-p.16TheFukushimaDaiichiIncident2.AccidentprogressionReactorIsolationpumpstops11.3.16:36inUnit1(Batteriesempty)14.3.13:25inUnit2(Pumpfailure)13.3.2:44inUnit3(Batteriesempty)DecayHeatproducesstillsteaminReactorpressureVesselPressurerisingOpeningthesteamrelievevalvesDischargeSteamintotheWet-WellDescendingoftheLiquidLevelintheReactorpressurevesselTheFukushimaDaiichiIncident–Dr.Ma