Thomas B Cochran Matthew G McKinzie - NRDC .TheFukushimaThe Fukushima Nuclear Disaster Implications

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  • The Fukushima Nuclear DisasterTheFukushimaNuclearDisasterImplicationsforNuclearPowerSafetyThomas B Cochran and Matthew G McKinzieThomasB.Cochran andMatthewG.McKinzieNaturalResourcesDefenseCouncil,Inc.(NRDC)

    InternationalWorkshoponNuclearEnergySafety:ImprovingSafetyintheAftermathoftheFukushimaCrisis

    Beijing,ChinaJune 2930 2011June29 30,2011

  • WhatHappenedatFukushima

  • Some slides taken from:Someslidestakenfrom:

  • ScaleoftheFukushimaDaiichiAccident

    1234

    SatelliteimageofFukushimaDaiichi,photographedaboutsevenyearsbeforethe2011earthquakeandtsunami.

  • ScaleoftheFukushimaDaiichiAccident

    2341

    234

    TsunamiDamage

    SatelliteimageofFukushimaDaiichi,photographedaftertheearthquakeandtsunami,duringstationblackout,butbeforeexplosionsandfires.

  • ScaleoftheFukushimaDaiichiAccident

    1234

    1

    Debrisfrom

    Explosions

    SatelliteimageofFukushimaDaiichi,photographedafterthemajorsequenceofexplosionsandfiresinUnits1,2,3and4.

  • CategoriesofLessonsfromFukushima

    A. AccidentinitiatorsB. CompliancewithsafetygoalsC Reactor systems to cope with severe accidentsC. ReactorsystemstocopewithsevereaccidentsD. SpentfuelpoolissuesE. Adequacy of the responses to severe accidentsE. AdequacyoftheresponsestosevereaccidentsF. AdequacyofradiationmonitoringG. AdequacyoftheemergencyresponsesH. Robustnessofthesafetyinfrastructureestablishedatthenuclearpowerstation

    I S f t ltI. Safetyculture

  • A.Accidentinitiators

    1.Strengthenmeasurestoprotectagainst:a.naturalexternalhazards:

    earthquakestsunamishurricanesandtyphoonstornadoesfloodsfloodstheimplicationsofpredictedsealevelriseandincreasedstormsurges

    duetoclimatechange.b.onsitehazards:

    firesc.malevolentacts:

    terroristattacksinsider threatsinsiderthreats

    2.Needtoperiodicallyreviewofthemagnitudeandpotentialconsequencesofaccidentinitiators.

    3.Needtoimprovewarningsystemsfortsunamisandtornadoes.p g y

  • PeakAcceleration(m/s2)with10%ProbabilityofExceedance in50Years

    http://www.seismo.ethz.ch/static/GSHAP/global/

  • http://maps.ngdc.noaa.gov/viewers/hazards/

  • B.Compliancewithsafetygoals

    1.Arereactorsadequatelysafe?2.Whataccidentscenariosshouldbewithinthe

    design basis?designbasis?3.Areoldreactordesigns,e.g.,GEBWRswithpoorly

    designed Mark 1 and Mark 2 containments,designedMark1andMark2containments,withsubsequentsafetyupgradessufficientlysafetocontinueoperationorhavetheirlicensesextended?

  • ReassessingtheFrequencyofPartialCoreMeltAccidents

    Worldwide 12 nuclear power reactors haveWorldwide, 12 nuclear power reactors have experienced fuel-damage or a partial core-melt accident:

    1. The Sodium Reactor Experiment (SRE) 2. Stationary Low-Power Reactor No. 1 (SL-1) 3. Enrico Fermi Reactor-1 4. Chapelcross-2 5. St. Laurent A-1 6. St. Laurent A-27. Three Mile Island-2 8. Chernobyl-4 9. Greifswald-5 10 F k hi D ii hi 110. Fukushima Daiichi-111. Fukushima Daiichi-212. Fukushima Daiichi-3

  • ReassessingtheFrequencyofPartialCoreMeltAccidents

    Worldwide, there have been: 582 nuclear power reactors that have operated

    approximately 14,400 reactor-years. 115 BWRs that have operated approximately 3,100

    reactor-years. 61 BWRs with Mark 1 and 2 containments that

    h t d f 1 900 thave operated for 1,900 reactor-years. 137 nuclear power plants that have been shut down

    after becoming operationalafter becoming operational

  • 1 i 14 h td t i d

    ReassessingtheFrequencyofPartialCoreMeltAccidents

    1 in 14 shutdown reactors experienced some form of fuel damage

    1 in 23 were shut down as a direct1 in 23 were shut down as a direct consequence of fuel damage

    frequency of core-melt accidents is about one q yin 1,300 reactor-years

    frequency of core-melt accidents in BWRs is b i 1 000about one in 1,000 reactor-years

    frequency of core-melt accidents in BWRs with Mk 1 & 2 containments is about one inwith Mk 1 & 2 containments is about one in 630 reactor-years

  • C.Reactorsystemstocopewithsevereaccidents.

    ff d d l d f l1.SecureACpoweroffsiteandemergencydieselgeneratorsandgeneratorfuel2.DCpowerlongevityofbatteries3.Ensuringthewatertightnessofessentialequipmentfacilities.4.Forseveresituations,suchastotallossofoffsitepowerorlossofallheat, p

    sinksortheengineeringsafetysystems,simplealternativesourcesforthesefunctionsincludinganynecessaryequipment(suchasmobilepower,compressedairandwatersupplies)shouldbeprovidedforsevereaccident

    tmanagement.5.SuchprovisionsasareidentifiedinLesson4aboveshouldbelocated

    atasafeplaceandtheplantoperatorsshouldbetrainedtousethem.Thismayinvolvecentralizedstoresandmeanstorapidlytransferthemtotheaffectedsite(s).

    6.Nuclearsitesshouldhaveadequateonsiteseismicallyrobust,suitablyshielded,ventilatedandwellequippedbuildingstohousetheEmergencyResponse Centres with similar capabilities to those provided at FukushimaResponseCentres,withsimilarcapabilitiestothoseprovidedatFukushimaDaini andDaiichi,whicharealsosecureagainstotherexternalhazardssuchasflooding.Theywillrequiresufficientprovisionsandmustbesizedtomaintainthewelfareandradiologicalprotectionofworkersneededtomanagetheaccident.

  • C.Reactorsystemstocopewithsevereaccidents.

    h ld h l bl f bl l7.EmergencyResponseCentres shouldhaveavailableasfaraspracticableessentialsafetyrelatedparametersbasedonhardenedinstrumentationandlinessuchascoolantlevels,containmentstatus,pressure,etc.,andhavesufficientsecurecommunicationlinestocontrolroomsandotherplacesonsiteandoffsite.p

    8.Securerobustemergencycorecoolingsystemsforthereactorandthepressurizedcontainmentvessel(PCV)

    9.FuelmeltingandfallingtothebottomofthePCV.10 F l lti th h th PCV i t th t t i t10.FuelmeltingthroughthePCVintothereactorcontainments11.Escapeofasignificantfractionoftheradioisotopesfromthecontainments

    intothereactorbuildingsandfromthereintotheenvironment.12.Needforsystemstocopewithlargevolumesofcontaminatedwaterinthe

    eventofabreachofthereactorpressurevessel(RPV).13.Instrumentationformeasuringstatusofreactorsandspentfuelpools.Greater

    considerationshouldbegiventoprovidinghardenedsystems,communicationsand sources of monitoring equipment for providing essential information forandsourcesofmonitoringequipmentforprovidingessentialinformationforonsiteandoffsiteresponses,especiallyforsevereaccidents.

  • C.Reactorsystemstocopewithsevereaccidents.

    f l h ld b l l d d f l l14.Commoncausefailureshouldbeparticularlyconsideredformultipleunitsitesandmultiplesites,andforindependentunitrecoveryoptions,utilizingallonsiteresourcesshouldbeprovided.Externaleventshaveapotentialofaffectingseveralplantsandseveralunitsattheplantsatthesametime.Thisrequiresap p qsufficientlylargeresourceintermsoftrainedexperiencedpeople,equipment,suppliesandexternalsupport.Anadequatepoolofexperiencedpersonnelwhocandealwitheachtypeofunitandcanbecalledupontosupporttheaffectedit h ld b dsitesshouldbeensured.

    15.TheinternationalnuclearcommunityshouldtakeadvantageofthedataandinformationgeneratedfromtheFukushimaaccidenttoimproveandrefinetheexistingmethodsandmodelstodeterminethesourceterminvolvedinanuclearaccidentandrefineemergencyplanningarrangements.

  • D.Spentfuelpoolissues

    b l f f f l l1.Securerobustcoolingfunctionsofspentfuelpools2.SeeCategoryC,Lesson13above3.PlacementofspentfuelpoolsinnewreactorandNPSdesigns4 Move spent fuel from wet pools to dry casks as soon as practicable4.Movespentfuelfromwetpoolstodrycasksassoonaspracticable.

  • E.Adequacyoftheresponsestosevereaccidents

    l f ll1.Hydrogenproductionduetosteamcladdinginteractionsfollowinguncoveringofthecore;enhancementofpreventionmeasures.Theriskandimplicationsofhydrogenexplosionsshouldberevisitedandnecessary mitigating systems should be implementednecessarymitigatingsystemsshouldbeimplemented.

    2.Enhancementofthecontainmentventingsystem.3.Trainingrespondingtosevereaccident4 Central control of emergency supplies and equipment and setting up4.Centralcontrolofemergencysuppliesandequipmentandsettingup

    rescueteam.5.Thoroughaccidentmanagementmeasures.6.Improvementofaccidentresponseenvironment.SevereAccidentp pManagementGuidelinesandassociatedproceduresshouldtakeaccountofthepotentialunavailabilityofinstruments,lighting,powerandabnormalconditionsincludingplantstateandhighradiationfields.

  • F.Adequacyofradiationmonitoring

    h f1.Enhanceradiationexposuremeasurementsystemsforroutineoperationsandduringaccidents.

    2.Adequateidentificationandforecastoftheeffectofreleasedradioactive materialsradioactivematerials.

    3.Enhanceradiationexposuremanagementforworkers.Largescaleradiationprotectionforworkersonsitesundersevereaccidentconditions can be effective if appropriately organized and with well ledconditionscanbeeffectiveifappropriatelyorganizedandwithwellledandsuitabletrainedstaff.

    6.Exercisesanddrillsforonsiteworkersandexternalrespondersinordertoestablisheffectiveonsiteradiologicalprotectioninsevereg paccidentconditionswouldbenefitfromtakingaccountofexperiencesatFukushima.

    7.Enhanceradiationexposuremanagementofmembersofthepublic.

  • G.Adequacyoftheemergencyresponses

    b f b h l l l1.Responsetocombinedemergencyofbothlargescalenaturaldisasterandprolongednuclearaccident

    2.Establishmentofcleardivisionoflaborbetweenrelevantcentralandlocal organizationslocalorganizations.

    3.Enhancementofcommunicationrelevanttotheaccident.4.Enhancementofresponsetoassistancebyothercountriesand

    communication to the international communitycommunicationtotheinternationalcommunity.5.Cleardefinitionofwidespreadevacuationareaandradiological

    protectionguidelineinnuclearemergency.6.Whichreactorsitesarelocatedinareasthatcannotbeadequatelyq y