HYDROGEOLOGY AND GROUND WATER QUALITY AT THE … · UNC Mill Site Ground Water History 1980s-2015...
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HYDROGEOLOGY AND GROUND WATER QUALITY AT THE UNITED NUCLEAR CORPORATION URANIUM MILL, CHURCK ROCK, NEW MEXICO Earle C. Dixon Environmental ScienEst Tsali Associates
Transcript of HYDROGEOLOGY AND GROUND WATER QUALITY AT THE … · UNC Mill Site Ground Water History 1980s-2015...
HYDROGEOLOGYANDGROUNDWATERQUALITYATTHEUNITEDNUCLEARCORPORATIONURANIUMMILL,CHURCKROCK,NEWMEXICO
EarleC.DixonEnvironmentalScienEst
TsaliAssociates
UNCMillSite–RegulatorySeKng• NuclearRegulatoryCommission(NRC):Responsibleforallonsite&beneaththefacility,insidepropertyboundarythroughlicense.
• EnvironmentalProtecEonAgency(EPA)Region6:Responsibleforoffsitegroundwatercleanup&exposurethroughCERCLA-NPL&1988ROD.
• NRC&EPAworktogetherunderanMOUtocleanupthesitetoUMTRCA&RODstandards.
• NMED&NavajoNaEonparEcipateindocumentreview-comment&decisionmaking-comment.
• Sitebecamemorecomplicatedw/planneddisposalofminewasteatUNCcentral&northdisposalponds.
EPARegion6,Dallas:UNCMillSite
EPARegion9,SanFrancisco:NECRMineSite
Southwestalvm(SWA)
Zone3,(Z3)
Zone1,(Z1)
MonitoringwelllocaEonmap2015,UNCMill,ChurchRock,NM
ChurchRockmineswaterdischargerates(gpm),
1968-1986
Zone3monitoringwellSWLdecline
projecEontoboeomofscreenelevaEon
2012GroundWaterFlowModelZone3seepage
Projectedmonitoringwelldrydates,Zone3,UNCMillSite,ChurchRock,NM
UNCMillSiteGroundWaterHistory1980s-2015(1of4)
• 1968:NECRstartsminingoperaEons,dewatering,1977UNCstartsmillingoperaEons,seepageproblemsby1981.
• 1979:Southtailingspondbreach.• 1980-1988:controversialperiodofinvesEgaEons,lawsuits,hearings,regulatorchange,&miningindustrydecline&closure.
• 1983:UNCMillSiteplacedonNaEonalPriorityList(NPL)orSuperfundforgrdw.
UNCMillSiteGroundWaterHistory1980s-2015(2of4)
• 1988RecordofDecision(ROD):selectedAlternaEve3–pumping&evaporaEonw/mistersfor3aquiferunitstostandards.
• ROD-onetableofgroundwatercleanupstandardsforthreedifferentaquiferunits.
• CleanupstandardsareacombinaEonofsitedata,laboratorydetecEonlimits,&healthrisklevels.
• Remedydidnotachievestandards&pumpflowratesbelowEPAcriteriasoremedyshutdownby2001.UNCconEnuesZone3pumping.
UNCMillSiteGroundWaterHistory1980s-2015(3of4)
• UNCrequestedalternaEvestopumping:technicalwaiverforstandards;insEtuEonalcontrols–nosupportfromNN,BIA,NMED.
• 2004-2006:beginformalprocesstoevaluateotherremedies&buildadecisionsupportdocumentrepositorytorevisethe1988RODcleanupstandardswhichneedrevision.
• 2006:SiteWideSupplementalFeasibilityStudy(SWSFS)beganinaphasedapproach.
UNCMillSiteGroundWaterHistory1980s-2015(4of4)
• 2008:Part1SWSFScompleted,ProUCLstaEsEcalstudyofUNCgroundwaterdatatocomputerevisedbackgroundvaluesforearlyCOCvaluesthatwereusedas1988RODstandards.
• 2010:Part2SWSFSAlternaEveremedyscreeninganalysis&costesEmateaccordingcompletedtoEPAcriteria.
• 2017:(?)Part3DetailedalternaEveremedyanalysis&costtoachieverevised/proposedvaluesforupdatedRODstandards.
PrimarygeochemicalreacEonforbufferingseepageimpactedgroundwater
Uv.HCO3CovariantRelaEonship
UNCMillSite–Status&Future• 2015:NRCapprovedAmendment52toUNCLicenseto
reviseGroundwaterProtecEonStandardsforselectmetals&radionuclidesin3hydrostraEgraphicunits.
• 2016-2017++:Part3SWSFScompleted(?)thenEPAsystemaEcallystartsrevisionprocessto1988ROD?
• Lookingforward:UNCSiteneedstoachieveclosure&beremovedfromNPLinordertomovesitestewardshipunderUMTRCAtoDepartmentofEnergy(DOE)LegacyManagementbytransferofLicense.
• NECRminewastetobedisposedatUNCSite&closedunderNRCLicense-neverbeendonebefore?
• NRC,EPAs,NN,UNC-GE,&DOEworkingtogether.• DOEwillbecomelong-termsitemanager??
The End.
Thank you.
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