ML19093B815
| ML19093B815 | |
| Person / Time | |
|---|---|
| Issue date: | 02/12/2019 |
| From: | Bixler N, Clayton D Office of Nuclear Regulatory Research, Sandia, US Dept of Energy, National Nuclear Security Admin |
| To: | |
| Shared Package | |
| ML19093B814 | List: |
| References | |
| Download: ML19093B815 (15) | |
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Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energys National Nuclear Security Administration under contract DE-NA-0003525.
SAND2019-0794 C NathanE.BixlerandDanielJ.Clayton SandiaNationalLaboratories Presentedatthe31st AnnualRegulatoryInformationConference Bethesda,MD,USA,March14,2019 AtmosphericTransportResultsforBenchmarkStudyoftheAccidentat theFukushimaDaiichiNuclearPowerStation(BSAF)PhaseII
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Overview BSAFProject NRC/SNLMELCOR sourceterm Sensitivityofdeposition tometeorologicaldata Sensitivityofdeposition tosourceterm Summary 2
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OECD/NEABSAFPhaseI BSAFwas initiatedbytheNuclearEnergyAgency(NEA)of the Organisation forEconomicCooperationandDevelopment (OECD)
BSAFisamultiphasestudywithparticipantsfrommultiple countries PhaseIwascompletedin2015 Focuswastobetterunderstandaccidentprogressionateachofthe threeunitsoverthefirst6days Newknowledgewastoguidedecommissioning NRC/SNL(SandiaNationalLabs)contributedbyperformingMELCOR analysesofeachunit 3
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OECD/NEABSAFPhaseII PhaseIIwascompletedin2018 Focuswastoextendinvestigationofaccidentprogression,toevaluate sourceterm,andtoestimateatmospherictransportovertheentire accident(3weeks)
Researchimprovedunderstandingofreactorendstatesfor decommissioning NRC/SNLcontributedbyperformingMELCOR,HYSPLIT,andMACCS calculationsforeachunit 4
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ObjectivesofAtmospheric TransportAnalysistoSupportBSAF Provideguidancetosourcetermmodelersbyestimating grounddepositionpatterns FocusonCs137(bestquantifiedofthereleasedisotopes)
Depositionpatterndependscriticallyonchronologicalalignmentof releasewithweatherpattern Benchmarkatmospherictransportmodelsagainstrealdata HYSPLITparticletrackingmodel Asastandalonemodel IntegratedwithMACCS ResultsinthispresentationuseHYSPLITinstandalonemode 5
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TwoMajorSourcesof Uncertainty Uncertaintyinweatherwasinvestigatedusingthreesources ofweatherdata,allfromNOAA WRF(WeatherResearchandForecasting)model,generatedin2014 4kmspatial,20mintemporaldiscretization Nonudging GDAS(GlobalDataAssimilationSystem) 0.5degreesspatial,3hourtemporaldiscretization Nonudging WRFmodel,generatedin2017 4kmspatial,5mintemporaldiscretization Nudgedwithobservations Uncertaintyinsourcetermwasassessedusingsourceterms fromBSAFcontributors 6
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MeteorologicalDatafor First7Days Weatherdatahavesimilar trends but Significantvariationsin detail 7
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EvolutionofIntegralReleaseEstimated byNRC/SNL
Curvesindicateevolutionofintegralreleaseforthreeunitsasestimated byNRC/SNLoverthecourseofBSAFPhaseII
Manyoftheinitialandboundaryconditionsneededtoestimateaccident progressionwerepoorlyunderstood Initialdamagestatewasunknown Waterinjectionmayhavefailed,succeeded,orpartiallysucceeded 8
0 5
10 15 20 25 30 35 40 0
5 10 15 20 25 30 Cs-137 Integral Release (PBq)
Elaspsed Time (day)
H Terada et al.
IRSN IRSN (update)
JAEA/NSC JNES/TEPCO Stohl et al.
TEPCO Winiarek et al.
ZAMG SNL MELCOR 7/2016 SNL MELCOR 1/2017 SNL MELCOR 7/2017 SNL MELCOR 1/2018 SNL MELCOR 5/2018
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WeatherDataComparison 9
WRF 2017 GDAS WRF 2014 SNL MELCOR 5/2018 Observations Plots use
- Consistent scale
- Consistent isopleth shading (1 additional level in SNL plots)
2/12/2019 10 PredictedGroundDeposition 10 WRF 2017 SNL MELCOR 5/2018 Source Term
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- Figuresshowfinaldepositionpatternscreatedbyeachunitbasedon finalNRC/SNLsourcetermusingWRF2017weatherdata
- Unit1contributesverylittletotheoverallpattern
- Unit2and,toalesserextent,Unit3createmuchoftheNW depositionpattern,mostlyon3/15 ContributionstoDeposition PatternfromIndividualUnits Unit 1 Unit 2 Unit 3
2/12/2019 12 BSAFSourceTerms SNLreceivedsourcetermsfromeightBSAForganizations Fourprovidedasourcetermforallthreeunits GRS(Germany)reconstructedasourcetermusingdatafrom radiationmonitorsintheareasurroundingFukushima (reversemethod) 12 Organization Country Code Units SNL USA MELCOR 1,2,&3 IAE Japan SAMPSON 1,2,&3 IRSN France ASTEC 1,2,&3 KAERI Korea MELCOR 1,2,&3 CIEMAT Spain MELCOR 1
CNL Canada MELCOR 2
CRIEPI Japan MAAP 2
PSI Switzerland MELCOR 3
2/12/2019 13 TotalSourceTermComparison 13
2/12/2019 14 TotalDepositionComparison UsingWRF2017WeatherData 14 GRS REVERSE METHOD NRC/SNL MELCOR IRSN ASTEC IAE SAMPSON KAERI MELCOR
2/12/2019 15 Summary NRC/SNLevaluatedatmospherictransportwith HYSPLITandMACCS Uncertaintyinmeteorologymakesasignificant differenceinthedepositionpattern Uncertaintyinsourcetermmakesanevenlarger differenceinthedepositionpattern Insightsfromatmospherictransportmodeling improvedthefidelityofthesourcetermsoverthe courseofBSAFPhaseII BSAFresultshaveprovidedpreliminaryguidancefor decommissioningtheFukushimaDaiichiunits 15