RS-12-166, Company, Llc’S 180-day Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding the Flooding Aspects of Recommendation 2.3 of the Near-Term Task Force Review of Insights from

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Company, Llc’S 180-day Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding the Flooding Aspects of Recommendation 2.3 of the Near-Term Task Force Review of Insights from
ML12332A304
Person / Time
Site: Clinton 
Issue date: 11/27/2012
From: Kaegi G
Exelon Generation Co
To:
Office of Nuclear Reactor Regulation, Document Control Desk
References
RS-12-166
Download: ML12332A304 (28)
v • d • e


Text

10 CFR 50.54(f)

RS-12-166 November 27, 2012 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk 11555 Rockville Pike Rockville, MD 20852 Clinton Power Station, Unit 1 Facility Operating License No. NPF-62 NRC Docket No. 50-461

Subject:

Exelon Generation Company, LLCs 180-day Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding the Flooding Aspects of Recommendation 2.3 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident

References:

1. NRC Letter, Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Recommendations 2.1, 2.3, and 9.3, of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident, dated March 12, 2012
2. NRC Letter, Endorsement of Nuclear Energy Institute (NEI) 12-07, Guidelines For Performing Verification Walkdowns of Plant Flood Protection Features, dated May 31, 2012
3. Exelon Generation Company, LLCs 90-day Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding Recommendations 2.1 and 2.3, of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident (Flooding), dated June 11, 2012 On March 12, 2012, the Nuclear Regulatory Commission (NRC) issued Reference 1 to all power reactor licensees. Enclosure 4 of Reference 1 contains specific Requested Actions, Requested Information, and Required Responses associated with Recommendation 2.3 for Flooding. On June 11, 2012, Exelon Generation Company, LLC (EGC) submitted the 90-day response requested in Enclosure 4 of Reference 1, confirming that EGC would use the NRC-endorsed flooding walkdown procedure (Reference 3).

U.S. Nuclear Regulatory Commission 180-Day Response to 50.54(f) Letter NTTF Recommendation 2.3: Flooding November 27, 2012 Page 2 For flooding Recommendation 2.3 (walkdowns), Enclosure 4 of Reference 1 states that within 180 days of the NRC's endorsement of the walkdown process (Reference 2), each addressee will submit a final response, including a list of any areas that are unable to be inspected due to inaccessibility and a schedule for when the walkdown will be completed. This letter provides the Clinton Power Station, Units 1 and 2 180-day response to Reference 1 for Flooding Recommendation 2.3.

Conditions identified during the walkdowns were documented and entered into the corrective action program. to this letter provides the requested information for Clinton Power Station.

This letter contains new regulatory commitments, which are identified in Enclosure 2.

Should you have any questions concerning the content of this letter, please contact Ron Gaston at (630) 657-3359.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 27th day of November 2012.

Respectfully, Glen T. Kaegi Director - Licensing & Regulatory Affairs Exelon Generation Company, LLC

Enclosures:

1.

Flooding Walkdown Report In Response To The 50.54(f) Information Request Regarding Near-Term Task Force Recommendation 2.3: Flooding for the Clinton Power Station

2. Summary of Regulatory Commitments cc:

Director, Office of Nuclear Reactor Regulation Regional Administrator - NRC Region III NRC Senior Resident Inspector - Clinton Power Station NRC Project Manager, NRR - Clinton Power Station Illinois Emergency Management Agency - Division of Nuclear Safety U.S. Nuclear Regulatory Commission 180-Day Response to 50.54(f) Letter NTTF Recommendation 2.3: Flooding November 27, 2012 Page 2 For flooding Recommendation 2.3 (walkdowns), Enclosure 4 of Reference 1 states that within 180 days of the NRC's endorsement of the walkdown process (Reference 2), each addressee will submit a final response, including a list of any areas that are unable to be inspected due to inaccessibility and a schedule for when the walkdown will be completed. This letter provides the Clinton Power Station, Units 1 and 2 180-day response to Reference 1 for Flooding Recommendation 2.3.

Conditions identified during the walkdowns were documented and entered into the corrective action program. to this letter provides the requested information for Clinton Power Station.

This letter contains new regulatory commitments, which are identified in Enclosure 2.

Should you have any questions concerning the content of this letter, please contact Ron Gaston at (630) 657-3359.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 27th day of November 2012.

Respectfully,

~~

61en T. Kaegi Director - Licensing & Regulatory Affairs Exelon Generation Company, LLC

Enclosures:

1. Flooding Walkdown Report In Response To The 50.54(f) Information Request Regarding Near-Term Task Force Recommendation 2.3: Flooding for the Clinton Power Station
2. Summary of Regulatory Commitments cc:

Director, Office of Nuclear Reactor Regulation Regional Administrator - NRC Region III NRC Senior Resident Inspector - Clinton Power Station NRC Project Manager, NRR - Clinton Power Station Illinois Emergency Management Agency - Division of Nuclear Safety U.S. Nuclear Regulatory Commission 180-Day Response to 50.54(f) Letter NTTF Recommendation 2.3: Flooding November 27, 2012 Page 2 For flooding Recommendation 2.3 (walkdowns), Enclosure 4 of Reference 1 states that within 180 days of the NRC's endorsement of the walkdown process (Reference 2), each addressee will submit a final response, including a list of any areas that are unable to be inspected due to inaccessibility and a schedule for when the walkdown will be completed. This letter provides the Clinton Power Station, Units 1 and 2 180-day response to Reference 1 for Flooding Recommendation 2.3.

Conditions identified during the walkdowns were documented and entered into the corrective action program. to this letter provides the requested information for Clinton Power Station.

This letter contains new regulatory commitments, which are identified in Enclosure 2.

Should you have any questions concerning the content of this letter, please contact Ron Gaston at (630) 657-3359.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 27th day of November 2012.

Respectfully,

~~

61en T. Kaegi Director - Licensing & Regulatory Affairs Exelon Generation Company, LLC

Enclosures:

1. Flooding Walkdown Report In Response To The 50.54(f) Information Request Regarding Near-Term Task Force Recommendation 2.3: Flooding for the Clinton Power Station
2. Summary of Regulatory Commitments cc:

Director, Office of Nuclear Reactor Regulation Regional Administrator - NRC Region III NRC Senior Resident Inspector - Clinton Power Station NRC Project Manager, NRR - Clinton Power Station Illinois Emergency Management Agency - Division of Nuclear Safety

U.S. Nuclear Regulatory Commission 180-Day Response to 50.54(f) Letter NTTF Recommendation 2.3: Flooding November 27, 2012 Page 3 Flooding Walkdown Report In Response To The 50.54(f) Information Request Regarding Near-Term Task Force Recommendation 2.3: Flooding for the Clinton Power Station (24 pages)

FLOODING WALKDOWN REPORT IN RESPONSE TO THE 50.54(f) INFORMATION REQUEST REGARDING NEAR-TERM TASK FORCE RECOMMENDATION 2.3: FLOODING for the CLINTON POWER STATION 8401 Power Road, Clinton, IL 61727 Facility Operating License No. NPF-62 NRC Docket No. 50-461 Exelon.

Exelon Generation Company, LLC 4300 Winfield Road, Warrenville IL 60555 Prepared by; Sargent & Lundy LLC 55 East Monroe Street, Chicago, IL 60603 100% Report, Rev. 1 (supersedes Rev. 0 in its entirety)

November 9, 2012 Printed Name/Title Preparer:

Dean W. Robinson Program Manager,_Sargent & Lundy Independent Reviewer:

Engineering Manager:

Lead Responsible Engineer:

Branch Manager:

Senior Manager:

Corporate Acceptance:

Signature Date Jeffrey Kerruish Manager,_Sargent&Lundy Rick Goetzke Project Manager, Sargent & Lundy 4i 144L,L1L

,-41+Ftl NI

/q / Iz Sr j k tLZ2 I I i1 O Ii Z.

FLOODING WALKDOWN REPORT IN RESPONSE TO THE 50.54(f) INFORMATION REQUEST REGARDING NEAR-TERM TASK FORCE RECOMMENDATION 2.3: FLOODING Preparer:

Independent Reviewer:

Engineering Manager:

Lead Responsible for the CLINTON POWER STATION 8401 Power Road, Clinton, IL 61727 Facility Operating License No. NPF-62 NRC Docket No. 50-461 4£F' ExeLon.

Exelon Generation Company, LLC 4300 Winfield Road, Warrenville IL 60555 Prepared by:

Sargent & Lundy LLC 55 East Monroe Street, Chicago, IL 60603 100% Report, Rev. 1 (supersedes Rev. 0 in its entirety)

November 9,2012 Printed Name/Title Dean W. Robinson Signature Program Manager, Sargent & Lundy Jeffrey Kerruish Manager, Sargent & Lundy Rick Goetzke Project Manager, Sargent & Lundy Engineer:

WA L I U L-BranchManage~

=/~~~IL:

. ~~~~~~~~~~~~~~~~~~~~~~~~

Senior Manager:

Corporate Acceptance:

FLOODING WALKDOWN REPORT IN RESPONSE TO THE 50.54(f) INFORMATION REQUEST REGARDING NEAR-TERM TASK FORCE RECOMMENDATION 2.3: FLOODING Preparer:

Independent Reviewer:

Engineering Manager:

Lead Responsible for the CLINTON POWER STATION 8401 Power Road, Clinton, IL 61727 Facility Operating License No. NPF-62 NRC Docket No. 50-461 4£F' ExeLon.

Exelon Generation Company, LLC 4300 Winfield Road, Warrenville IL 60555 Prepared by:

Sargent & Lundy LLC 55 East Monroe Street, Chicago, IL 60603 100% Report, Rev. 1 (supersedes Rev. 0 in its entirety)

November 9,2012 Printed Name/Title Dean W. Robinson Signature Program Manager, Sargent & Lundy Jeffrey Kerruish Manager, Sargent & Lundy Rick Goetzke Project Manager, Sargent & Lundy Engineer:

WA L I U L-BranchManage~

=/~~~IL:

. ~~~~~~~~~~~~~~~~~~~~~~~~

Senior Manager:

Corporate Acceptance:

Joseph V. Bellini/Flooding SME 11/20/12

NTTFRecommendation2.3(Walkdowns):Flooding ClintonPowerStation ExelonCorporation November9,2012 Revision1

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Contents

1.

EXECUTIVE

SUMMARY

............................................................................................................................... 2

2.

PURPOSE.................................................................................................................................................... 3

a.

Background........................................................................................................................................... 3

b.

SiteDescription..................................................................................................................................... 4

c.

RequestedActions................................................................................................................................ 6

d.

RequestedInformation......................................................................................................................... 7

3.

METHODOLOGY......................................................................................................................................... 8

a.

OverviewofNEI1207(WalkdownGuidance)..................................................................................... 8

b.

ApplicationofNEI1207....................................................................................................................... 9

c.

ReasonableSimulations...................................................................................................................... 10

d.

WalkdownInspectionGuidance......................................................................................................... 11

4.

RESULTS................................................................................................................................................... 12

a.

RequestedInformationItem2(a)-DesignBasisFloodHazards........................................................ 12

b.

RequestedInformationItem2(b)-CLBProtectionandMitigationFeatures.................................... 13

c.

RequestedInformationItem2(c)-FloodWarningSystems.............................................................. 15

d.

RequestedInformationItem2(d)-FloodProtectionSystem/BarrierEffectiveness......................... 15

e.

RequestedInformationItem2(e)-ImplementationofWalkdownProcess...................................... 16

f.

RequestedInformationItem2(f)-FindingsandCorrectiveActionsTaken/Planned........................ 17

g.

RequestedInformationItem2(g)-Cliff-EdgeEffectsandAvailablePhysicalMargin..................... 19

h.

RequestedInformationItem2(h)-Planned/NewlyInstalledFloodProtectionEnhancements....... 20

5.

CONCLUSIONS.......................................................................................................................................... 20

6.

REFERENCES............................................................................................................................................. 22

NTTFRecommendation2.3(Walkdowns):Flooding ClintonPowerStation ExelonCorporation November9,2012 Revision1

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1. EXECUTIVE

SUMMARY

In response to the Nuclear Regulatory Commission (NRC) Request for Information regarding NearTerm TaskForce(NTTF)Recommendation2.3,afloodingprotectionwalkdownwasconductedatClintonPower Station(CPS)toidentifyandaddressplantspecificdegraded,nonconforming,orunanalyzedconditionsof the plants flood protection features. The flooding walkdown was conducted between August 21 and August31,2012andincludedvisualinspectionsoffloodprotectionfeaturesandareasonablesimulationof theapplicablefloodprotectionproceduresteps.

The scope of the flooding walkdown was developed following a detailed review of all relevant current licensingdocuments.SinceCPSissituatedabovethelake/riverprobablemaximumflood(PMF)level,the stationreliesalmostentirelyonpassivefeaturesincorporatedinthedesigntokeepwateroutoftheplant, specifically site runoff from a local intense precipitation (LIP) event and groundwater. The flooding walkdownscopeconsistedoffourmainparts.

The walls, floors and penetrations through the walls and floors in the Circulating Water Screen HouseShutdownServiceWater(SX)cubicleswereinspected.Theserooms,locatedabovenormal lakewaterlevel,aredesignedandcreditedinthecurrentlicensingbasis(CLB)toremaindryduring aPMFwhenthelakelevelrisesabovetheroomfloorsandpartwayupthewalls.

Tworeasonablesimulationswereconducted.Thefirstwasanexercisetoinstallthewatertightfloor hatchintheSXBpumproom,todemonstratethataCPSAbnormalLakeLevelprocedurecould beimplementedintheeventofhighlakewaterlevel,astheseproceduralstepshavenotbeen performedinthepast.ThesecondsimulationwaslaterperformedtoensuretheSXpumproom roofhatchescouldbeopenedifneededtoprovidepersonnelaccessduringaflood.

An outdoor walkdown was conducted to ensure no topography changes, added structures or securitybarriersaffectsitedrainageasdescribedintheCLB.

The belowgrade structures (i.e., basement walls and basement slabs and penetrations through thesewallsandfloors)inthemainpowerblockwereinspected.TheseareasarecreditedintheCLB tokeepgroundwaterandrunofffromLIPoutofthesafetyrelatedbuildings.

Themethodologyandacceptancecriteriafortheevaluationoffloodprotectionfeatureswasdeveloped basedonNEIreport1207[Rev0A],GuidelinesforPerformingVerificationWalkdownsofPlantProtection Features.

Thevisualinspectionsofwalls,floorsandpenetrationsthroughthewallsandfloorsconcludedthatthere arenoobservablestructuraldeficienciesthatmayimpactthestructuresabilitytoperformitsintended flood protection function. The reasonable simulations demonstrated the applicable procedure can be performedsuccessfully.

Issue Reports (IRs) were entered into the Corrective Action Program (CAP) for all observations not immediately judged as acceptable. These issues were addressed in CAP and they were not reportable deficiencies.

NTTFRecommendation2.3(Walkdowns):Flooding ClintonPowerStation ExelonCorporation November9,2012 Revision1

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Recommended enhancements to the SX B pump room floor hatch were documented in IRs and implementedasdescribedintheresponsetoItem2(f),FindingsandCorrectiveActionsTaken/Planned.No otherchangesweredeterminednecessaryasaresultofthefloodwalkdownsatCPS.

Whetherconduitsfrommanholesorcablevaultscouldprovideapathforgroundwaterorrainwaterto enter safety related buildings was considered relevant to the walkdown scope. Conduits from manholes/cablevaultsgenerallyarenotroutedtosafetyrelatedbuildingsatCPS.Inafewcases,thereare entering conduits that turn upwards and terminate above grade level such that no path for water is provided.Thewalkdownscopeincludedinspectionsoftheexternalconduitseals.Internalconduitseals couldnotbevisuallyinspected;however,plantdesigndocumentationprovidesreasonableassurancethat the internal seals are installed, and evidence of groundwater/rainwater leakage through conduits into safetyrelatedbuildingsatCPSwasnotidentifiedduringthewalkdowns.Itwasconcludedthatconduitsat CPSdonotprovideapathforgroundwaterorrainwatertoentersafetyrelatedbuildings.

Asmallportionofthetotalfloorandwallareasandafewofthepenetrationswithinthewalkdownscope weredeemedinaccessibleandwerenotinspected.Reasonableassurancethattheseportionsofthewalls andfloorsandtheinaccessiblepenetrationsareacceptableisbasedonthefactthatvisualinspectionof accessiblewalls,floorsandpenetrationsthroughouttheplantrevealednodeficienciesordegradationthat wouldpreventperformanceoffloodprotectionfunctions.PerformanceofanexercisetoopentheSXpump room roof hatches was not completed, as demonstration of hatch removal would damage the roof. A simulationofthisprocesswassubsequentlysuccessfullyperformed.Thecondenserpitfloorareainthe TurbineBuildingwasconsideredarestrictedaccessareaandinspectionforsignsofgroundwaterinleakage wasdeferreduntilanoutage,asdoseinthisareaissignificantlyreducedwhentheplantisnotoperating.

ThenextrefuelingoutageatCPSiscurrentlyscheduledforOctober2013.

Performanceofthewalkdownsandsimulationsprovidedconfirmationthatfloodprotectionfeaturesarein place,areingoodconditionandwillperformascreditedinthecurrentlicensingbasis.Observationsnot immediatelyjudgedasacceptablewereaddressedanddispositionedundertheCAPprogram.Atotalof17 IRswereenteredintotheCAPasaresultofthiseffort.ThesearedescribedinTable2intheConclusions sectionofthisreport.

2. PURPOSE
a. Background InresponsetothenuclearfueldamageattheFukushimaDaiichipowerplantduetotheMarch11,2011 earthquakeandsubsequenttsunami,theUnitedStatesNuclearRegulatoryCommission(NRC)established theNearTermTaskForce(NTTF)toconductasystematicreviewofNRCprocessesandregulations,andto make recommendations to the Commission for its policy direction. The NTTF reported a set of recommendationsthatwereintendedtoclarifyandstrengthentheregulatoryframeworkforprotection againstnaturalphenomena.

OnMarch12,2012,theNRCissuedaninformationrequestpursuanttoTitle10oftheCodeofFederal Regulations,Section50.54(f)(10CFR50.54(f)or50.54(f))(Reference3)whichincludedsix(6)enclosures:

[NTTF]Recommendation2.1:Seismic

[NTTF]Recommendation2.1:Flooding

NTTFRecommendation2.3(Walkdowns):Flooding ClintonPowerStation ExelonCorporation November9,2012 Revision1

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[NTTF]Recommendation2.3:Seismic

[NTTF]Recommendation2.3:Flooding

[NTTF]Recommendation9.3:EP LicenseesandHoldersofConstructionPermits InEnclosure4ofReference3,theNRCrequestedthatlicenseesperformfloodprotectionwalkdownsto identify and address plantspecific degraded, nonconforming, or unanalyzed conditions and cliffedge effects(throughthecorrectiveactionprogram)andverifytheadequacyofmonitoringandmaintenance procedures. Cliffedge effects were defined by the NTTF Report (Reference 5), which noted that the safetyconsequencesofafloodingeventmayincreasesharplywithasmallincreaseinthefloodinglevel.

WhiletheNRCusedthesametermastheNTTFReportintheMarch12,201250.54(f)informationrequest (Reference3),theinformationtheNRCexpectsutilitiestoobtainduringtheRecommendation2.3:Flooding Walkdowns is different. To clarify, the NRC is now differentiating between cliffedge effects (which are dealt with under Enclosure 2 of Reference 3) and a new term, Available Physical Margin (APM). APM informationwillbecollectedduringthewalkdowns,butwillnotbereportedintheresponsetoEnclosure4 of Reference 3. The collected APM information will be available for use in developing the response to ofReference3.

Structures,systems,andcomponents(SSCs)importanttosafetyaredesignedeitherinaccordancewith,or meettheintentof,AppendixAto10CFRPart50,GeneralDesignCriteria(GDC)2.GDC2statesthatSSCs important to safety at nuclear power plants must be designed to withstand the effects of natural phenomena, including floods, without loss of capability to perform their intended safety functions. For flooding walkdowns, identifying/addressing plantspecific degraded, nonconforming, or unanalyzed conditions (through the corrective action program) and verifying the adequacy of monitoring and maintenanceproceduresisassociatedwithfloodprotectionandmitigationfeaturescreditedinthecurrent design/licensing basis. New flood hazard information will be considered in response to Enclosure 2 of Reference3.

OnbehalfofExelonGenerationCompany,LLC(Exelon),thisreportprovidestheinformationrequestedin theMarch12,201250.54(f)letter;specifically,theinformationlistedundertheRequestedInformation sectionofEnclosure4,paragraph2(athroughh).TheRequestedInformationsectionofEnclosure4, paragraph1(athroughj),regardingfloodingwalkdownprocedures,wasaddressedviaExelonsJune 11,2012,acceptance(Reference1)oftheindustrywalkdownguidance(Reference2).

b. SiteDescription PerUpdatedSafetyAnalysisReport(USAR)Section2.4(Reference13)CPSislocated6mileseastofthecity ofClinton,DeWittCountyincentralIllinois.ThecondensercoolingwaterisprovidedfromtheUshaped cooling lake (Lake Clinton) that has been formed by construction of a dam just downstream from the confluenceoftheNorthForkofSaltCreekwithSaltCreek.TheSaltCreekandNorthForkfingersoftheU shapedlakeextend14milesand8miles,respectively,upstreamfromthedam.Thedrainageareaofthe lakeis296mi2.Thesurfaceareaofthelakeis4895acres(7.65mi22.6%ofthedrainagearea)andthe storagecapacityis74,200acrefeetatanormalpoolelevationof690feet.(Allelevationsarebasedon meansealevel(MSL)datum,U.S.G.S.,1929adjustment.)

NTTFRecommendation2.3(Walkdowns):Flooding ClintonPowerStation ExelonCorporation November9,2012 Revision1

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Thestationislocatedbetweenthetwofingersofthelakewithastationgradeelevationof736feetand plantmainfloorelevationof737feet.Thestationisapproximately31/2milesnortheastofthedamand1 milesouthofIllinoisHighway54.ThestationCirculatingWaterScreenHouseislocatedontheNorthFork fingerofthelakewiththecirculatingwaterdischargingbackintotheSaltCreekfingerthroughadischarge flume.

Aconcreteservicespillwaywithanogeetypecrestisprovidedonthewestabutmentofthedamtopass floods.Anauxiliaryspillwayisprovidedontheeastabutmenttopassfloodsmoreseverethanoncein100 yearsrecurrenceincludingtheprobablemaximumflood(PMF).Alakeoutletstructureislocatednearthe west abutment to provide a minimum downstream release of 5 cfs. The ultimate heat sink for the emergencycorecoolingsystemisprovidedwithinthecoolinglakebyconstructingasubmergeddamacross theNorthForkwithanapproachchannelleadingintotheCirculatingWaterScreenHouse.

ThePMFrunoffintothelakeroutedthroughthespillwayswillraisethelakewaterleveltoelevation708.8 feetatthedamsite.ThebackwatereffectalongtheNorthForkfingerwillraisethePMFwaterlevelatthe stationsitetoelevation708.9feet.Superimposingthewindwaveeffectduetoasustained40mphwind actingontheprobablemaximumwaterlevelwillresultinwaverunupelevationsof711.9feetand713.8 feetforsignificantwavesandmaximum(1%)waves,respectively,atthestationsite.Forpurposesofthe walkdowns performed for this report, the PMF is taken as 713.8 feet. The station's Seismic Category I structureswithgradeelevationof736feetwillnotbeaffectedbythePMFdesignconditions.However, floodprotectionforthesafetyrelatedsystemsandcomponentsintheCirculatingWaterScreenHouseis providedtoelevation714feet.

ThefollowingprotectionmeasuresareadoptedforSeismicCategoryIsystemsandcomponentslocatedin theCirculatingWaterScreenHouseandlocatedbelowthePMFlevel.

a.

Waterstopsareprovidedinallconstructionjointsuptothemaximumfloodlevel.

b.

Watersealringsareprovidedforallpenetrationsinexteriorwallsbelowthemaximumfloodlevel.

c.

Watertight doors designed to withstand the hydrostatic head of the maximum flood level are providedforalldoorwayslocatedonboththeentrancewallsandtheinternalwallsoftheSXpump roomswhicharebelowthemaximumfloodlevel.

d.

Ahatchisprovidedontheroofoftheessentialservicewaterpumpstructure(elevation730feet) foraccessduringPMF.

ThemeasureslistedabovearenotrequiredattheCPSmainpowerblockbuildings,becausegradeatthe stationsiteiswellabovethePMFlevel.However,thesemeasuresareadoptedfortheportionsofthe structures at the station site located below the maximum groundwater level. Per the CPS USAR, the groundwatertableattheCPSsiteisconservativelytakenaselevation730feet.Allsubstructuresbelow elevation730feetattheCPSsitearedesignedtowithstandfullhydrostaticheadofgroundwater.

Theareassurroundingtheplantaregradedtodirectsurfacerunoffawayfromtheplant.Thestationarea is provided with a drainage system which will drain into Salt Creek and the North Fork; however, it is conservatively assumed in the USAR analysis that the local surface drainage system would not function duringtheLIPevent.

TheestimatedmaximumwatersurfaceelevationaroundtheplantasaresultofLIPislowerthantheplant floorelevationof737.0feet,exceptonthenorthernsideoftheplantovertheportionsenclosedbythe

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curvedtracks5,6,and7wheretheelevationwouldbeabout737.2feet.Onlythesouthernhalfofthe structure contains safetyrelated equipment. About 0.2 foot depth of water standing outside on the northernsideofthestructureabovetheplantfloorelevation737.0feetwouldnotaffectthesafetyrelated systemfunctionsbecause thereisnobelowgradesafetyrelatedequipmentinthenorthernhalfofthe plant.Thefloordrainsystemwouldtakecareofthewaterthatmightenterthebuilding.Therefore,the safetyrelateditemswouldnotbeaffectedbysurfacewateringressintothenorthernsideofthestructure.

The maximum water surface elevation due to a LIP is 736.8 feet in the immediate station area where safetyrelatedfacilitiesarelocated(southernhalfofthemainpowerblockstructure).Withthestation floorelevationat737feet,thesafetyrelatedfacilitieswouldnotbeaffectedbytheLIP.

FortheUnit2excavation,ithasbeenconservativelyestimatedthatduringthe48hourPMPevent,without consideringtheprotectingeffectofthesurroundingearthbermsandwithoutthebenefitofanydrainage outoftheexcavation,theelevationoftheimpoundedrainwaterrunoffwillbe728ft.

AccesstothestationisviaIllinoisHighway54.Thegroundtopographyalongthestationaccessrouteis favorablyhighandthegradeshavebeenlocatedwellabovethePMFlevel.Thestationaccessroaddoes notcrossanystreamandwillnotbeaffectedbyanyfloodconditionsatthesite.

c. RequestedActions PerEnclosure4ofReference3,theNRCrequeststhateachlicenseeconfirmuseoftheindustrydeveloped, NRCendorsed,floodwalkdownprocedures

orprovideadescriptionofplantspecificwalkdownprocedures.

In a letter dated June 11, 2012 (Reference 1), Exelon confirmed that the flooding walkdown procedure (Reference2),endorsedbytheNRConMay31,2012,willbeusedasthebasisforthefloodingwalkdowns.

OtherNRCsrequestedactionsinclude:

(1) PerformfloodprotectionwalkdownsusinganNRCendorsedwalkdownmethodology; (2) Identifyandaddressplantspecificdegraded,nonconforming,orunanalyzedconditions,aswellas, cliffedge effects through the corrective action program, and consider these findings in the Recommendation2.1hazardevaluations,asappropriate; (3) Identifyanyotheractionstakenorplannedtofurtherenhancethesitefloodprotection; (4) Verifytheadequacyofprograms,monitoringandmaintenanceforprotectionfeatures;and (5) ReporttotheNRCtheresultsofthewalkdownsandcorrectiveactionstakenorplanned. of Reference 3 also states, If any condition identified during the walkdown activities represents a degraded, nonconforming, or unanalyzed condition (i.e. noncompliance with the current licensingbasis)foranSSC,describeactionsthatweretakenorareplannedtoaddresstheconditionusing theguidanceinReference6,includingenteringtheconditioninthecorrectiveactionprogram.Reporting requirementspursuantto10CFR50.72shouldalsobeconsidered.

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d. RequestedInformation PerEnclosure4ofReference3,
1. TheNRCrequeststhateachlicenseeconfirmthatitwillusetheindustrydeveloped,NRCendorsed, floodingwalkdownproceduresorprovideadescriptionofplantspecificwalkdownprocedures.As indicatedpreviously,ExelonsletterdatedJune11,2012(Reference1),confirmedthattheflooding walkdownprocedure(Reference2),endorsedbytheNRConMay31,2012,willbeusedasthe basisforthefloodingwalkdowns.
2. The NRC requests that each licensee conduct the walkdown and submit a final report which includesthefollowing:
a. Describe the design basis flood hazard level(s) for all floodcausing mechanisms, including groundwateringress.
b. Describe protection and mitigation features that are considered in the licensing basis evaluationtoprotectagainstexternalingressofwaterintoSSCsimportanttosafety.
c. Describeanywarningsystemstodetectthepresenceofwaterinroomsimportanttosafety.
d. Discuss the effectiveness of flood protection systems and exterior, incorporated, and temporary flood barriers. Discuss how these systems and barriers were evaluated using the acceptancecriteriadevelopedaspartofRequestedInformationitem1.h.
e. Presentinformationrelatedtotheimplementationofthewalkdownprocess(e.g.,detailsof selectionofthewalkdownteamandprocedures)usingthedocumentationtemplatediscussed inRequestedInformationitem1.j,includingactionstakeninresponsetothepeerreview.
f.

Results of the walkdown including key findings and identified degraded, nonconforming, or unanalyzed conditions. Include a detailed description of the actions taken or planned to addresstheseconditionsusingtheguidanceinRegulatoryIssuesSummary200520,Revision1, Revision to NRC Inspection Manual Part 9900 Technical Guidance, "Operability Conditions AdversetoQualityorSafety,"includingenteringtheconditioninthecorrectiveactionprogram.

g. Documentanycliffedgeeffectsidentifiedandtheassociatedbasis.Indicatethosethatwere enteredintothecorrectiveactionprogram.Alsoincludeadetaileddescriptionoftheactions takenorplannedtoaddresstheseeffects.SeenoteinSection2aregardingtheNRCschangein positiononcliffedgeeffects.
h. Describe any other planned or newly installed flood protection systems or flood mitigation measures including flood barriers that further enhance the flood protection. Identify results andanysubsequentactionstakeninresponsetothepeerreview.

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3. METHODOLOGY
a. OverviewofNEI1207(WalkdownGuidance)

InacollaborativeeffortwithNRCstaff,NEIdevelopedandissuedreport1207[Rev0A],Guidelinesfor PerformingVerificationWalkdownsofPlantProtectionFeatures,datedMay2012(Reference2).TheNRC endorsed NEI 1207 on May 31, 2012 with amendments. NEI 1207 was updated to incorporate the amendments and reissued on June 18, 2012. On June 11, 2012, Exelon issued a letter to the NRC (Reference1)statingthattheendorsedfloodingwalkdownprocedure(Reference2)willbeusedasthe basisforthefloodingwalkdowns.NEI1207providesguidanceonthefollowingitems:

Definitions o IncorporatedBarrier/Feature o TemporaryBarrier/Feature o ExteriorBarrier/Feature o CurrentLicensingBasis(CLB) o DesignBases o Inaccessible o RestrictedAccess o Deficiency o FloodProtectionFeatures o ReasonableSimulation o VisualInspection o CliffEdgeEffects o AvailablePhysicalMargin o VarietyOfSiteConditions o FloodDuration Scope o BasisforEstablishingWalkdownScope o IdentifyFloodProtectionFeatures(WalkdownList)

Methodology o DevelopWalkdownScope o PrepareWalkdownPackages o WalkdownTeamSelectionandTraining o PerformPreJobBriefs o InspectionofFloodProtectionAndMitigationFeatures General IncorporatedorExteriorPassiveFloodProtectionFeatures IncorporatedorExteriorActiveFloodProtectionFeatures TemporaryPassiveFloodProtectionFeatures TemporaryActiveFloodProtectionFeatures ProcedureWalkthroughandReasonableSimulation o ReviewofTheMaintenanceandMonitoringofFloodProtectionFeatures o ReviewofOperatingProcedures o DocumentationofAvailablePhysicalMargins

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o DocumentingPossibleDeficiencies o RestrictedAccess,orInaccessible AcceptanceCriteria EvaluationandReportingResultsofTheWalkdown RelatedInformationSources Examples WalkdownRecordForm SampleTrainingContent WalkdownReport

b. ApplicationofNEI1207 Exelonsapproachtothefloodingwalkdownsincludedthreephases:

Phase1-Preparation,Training,DataGathering,andScoping Exelon developed a fleetwide program and training course for walkdown team members to providecompleteandconsistentimplementationofNEI1207guidelines.Inadditionallwalkdown teammemberscompletedtheapplicableNANTeLtrainingandtesting.Datagatheringbeganwith identificationofstationspecificlicensingcommitmentsandstationdesignbasisrelativetoexternal floodingevents.Thisincludedreview oftheCPSUSAR,identificationofdrawingsshowingflood protection features and review of station procedures and calculations relative external flooding events. A walkdown scope was developed to capture station features credited as performing a floodprotectionfunctioninthecurrentlicensingbasis.Awalkdownlistwaspreparedidentifying thespecificfeaturestobeinspected.Foreachfeatureonthewalkdownlistawalkdownpackage waspreparedforusebythewalkdownteaminperforminganddocumentingthewalkdown.

ThescopedevelopedforthewalkdownsatCPSincludedthefollowing:

The floors and exterior watertight walls (up to PMF elevation) of the shutdown service water(SX)pumproomsintheCirculatingWaterScreenHouse.Scopeincludedinspection ofallpenetrationsandwatertightdoorsinthewallsinspected.InteriorwallsbetweenSX pumproomswerenotinspected.

Thefloorsandexteriorwatertightwalls(uptomaximumwaterlevelduetolocalintense precipitation (LIP) resulting from PMP) of all main power block buildings. This included exterior walls and basement floors of the Auxiliary, Fuel, Control, Diesel Generator, RadwasteandTurbinebuildings.Interiorwallsbetweenthebuildingswerenotinspected.

The Containment building was not included in the inspection scope because it has no exteriorwallsandtheflooriscreditedwithleaktightnessbasedontheperiodicIntegrated Leak Rate Testing (ILRT) and by comparison with the results of floor inspections of the surroundingbuildings(noissueswithfloorswereidentified).Thefloordrainsystemsinthe TurbineandRadwastebuildingswereincludedintheinspectionscopeastheyarecredited inaddressingpostulatedinleakageduetothemaximumLIPwaterlevel.

Whetherconduitsfrommanholesorcablevaultscouldprovideapathforgroundwateror rain water to enter safety related buildings was considered relevant to the walkdown

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scope. Conduits from manholes/cable vaults generally are not routed to safety related buildings at CPS. In a few cases there are entering conduits that turn upwards and terminateabovegradelevelsuchthatnopathforwaterisprovided.Thewalkdownscope included inspections of the external conduit seals. Internal conduit seals could not be visuallyinspectedbutareprovidedbydesign.Evidenceofgroundwater/rainwaterleakage throughconduitsintosafetyrelatedbuildingsatCPShasnotbeenidentifiedinthepastand wasnotidentifiedduringthewalkdowns.ConduitsatCPSdonotprovideapathforground waterorrainwatertoentersafetyrelatedbuildings.

An outdoor walkdown was conducted to ensure no topography changes or added structuresorsecuritybarriersaffectsitedrainageasdescribedintheCLB.

Phase2-InspectionsandReasonableSimulations Visual inspection of each feature and reasonable simulation, where applicable, was performed during the walkdowns and the results were documented on the Walkdown Record Forms. The condition of each feature as observed was compared to the acceptance criteria defined in the Supplemental Walkdown/Inspection Guidance (Reference 16). Two reasonable simulations were conducted; an exercise to install the watertight floor hatch in the SX B pump room to demonstratetheCPSprocedurecouldbeimplementedintheeventofhighlakewaterlevelanda simulationofthestepsrequiredtoopentheSXpumproomroofhatchestoprovideaccessduringa flood.

Phase3-FinalReporting The Walkdown Record Forms were completed and assembled into a package that included a summaryandacoverpagetodocumentamanagementreviewoftheentirepackage.Completion of the Walkdown Record Forms was performed in accordance with the guidance provided in Section7ofNEI1207.AFloodingWalkdownReport(thisreport)waspreparedtoaddressthe items outlined in the Requested Information section of the Recommendation 2.3: Flooding enclosurefromthe10CFR50.54(f)letter.

c. ReasonableSimulations A procedure walkthrough, or Reasonable Simulation, was conducted for temporary and/or active features that require manual/operator actions to perform their intended flood protection function. The purpose of the reasonable simulations was to verify the procedure or activity can be executed as specified/written.PerNEI1207,reasonablesimulationincludedthefollowing:

Verifythatanycreditedtimedependentactivitiescanbecompletedinthetimerequired.Time dependentactivitiesincludedetection(somesignalthattheeventwilloccur,hasoccurred,oris occurring), recognition (by someone who will notify the plant), communication (to the control room),andaction(byplantstaff).

Verifythatspecifiedequipment/toolsareproperlystagedandingoodworkingcondition.

Verifythatconnection/installationpointsareaccessible.

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Verifythattheexecutionoftheactivitywillnotbeimpededbytheeventitisintendedtomitigate or prevent. For example, movement of equipment across unpaved areas on the site could be impededbysoftsoilconditionscreatedbyexcessivewater.

Reviewtherelianceonthestationstafftoexecuterequiredfloodprotectionfeatures.Ifduringthe review several activities are identified to rely on station staff, then perform and document an evaluationoftheaggregateeffectonthestationstafftodemonstrateallactionscanbecompleted asrequired.

Verify that all resources needed to complete the actions will be available. (Note that staffing assumptionsmustbeconsistentwithsiteaccessassumptionsinemergencyplanningprocedures.)

Showthattheexecutionoftheactivitywillnotbeimpededbyotheradverseconditionsthatcould reasonably be expected to simultaneously occur (for example, winds, lightning, and extreme air temperatures).

Personnel/departments that have responsibility for supporting or implementing the procedure shouldparticipateinthesimulationeffort.

The simulation should demonstrate that the personnel assigned to the procedure do not have otherdutiesthatcouldkeepthemfromcompletingtheirfloodprotectionactivitiesduringanactual event.Actionsthatwouldbeperformedinparallelduringaneventshouldbesimulatedinparallel; notcheckedindividuallyandtheresultscombined.

Reasonablesimulationneednotrequiretheactualperformanceofthenecessaryactivitiesifthey have been previously performed and documented or it is periodically demonstrated and documentedthattheactivitiescanbecompletedinthecreditedtime.

AreviewofCPSproceduresidentifiedoneprocedurerequiringoperatoractiontoprotectsafetyrelated equipment in response to flooding concerns. CPS 4303.02 (Reference 17) requires monitoring the screenhousetunnelforinleakageintheeventofhighlakewaterlevel.TheopenaccesshatchintheSX BpumproomflooristobeclosedintheeventofinleakagetoreestablishSXpumproomwatertight integrity. As installation of the hatch had not been previously performed and documented, CPS demonstrated that hatch installation can be implemented if required. In addition, a simulation was performedtoprovideassurancetheSXpumproomroofhatchescanbeopenedduringaPMF.

d. WalkdownInspectionGuidance AWalkdownInspectionGuidancewasdevelopedbyExelontosupplementNEI1207,basedlargelyon AppendixAofNEI1207(Examples).Theguidancewasintendedtosupplement,notsupersede,NEI1207 andprovideinspectionguidanceforspecificfeatures,listedbelow.

IncorporatedorExteriorPassiveFeatures:

o SiteElevationsandTopography o EarthenFeatures(i.e.,FloodProtectionBerm,Dike,Levee) o ConcreteandSteelStructures o Wall,Ceiling,andFloorSeals(e.g.PenetrationSeals,CorkSeals) o PassiveFloodBarriersorWaterDiversionStructures

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o DrainsandCatchBasins o PlugsandManholeCovers o DrainagePathways(Swales,SubsurfaceDrainageSystem,etc.)

o PipingandCableVaultsandTunnels,ElectricalCableConduit o FloorHatches o FlapGate/BackwaterValve/DuckbillValve o FloodWall IncorporatedorExteriorActiveFeatures:

o CreditedWaterTightDoors o CreditedNonWatertightDoors o Pumps o WaterLevelIndication o GateValves TemporaryPassiveFeatures:

o PortableFloodBarriersandInflatableRubberSeals o FloodGate TemporaryActiveFeature o Pumps

4. RESULTS TheinformationrequestedinReference3,Enclosure4,underparagraph2oftheRequestedInformation section,isprovidedbelow.ThecontentsofeachitemweredevelopedinaccordancewithReference2, AppendixD.
a. RequestedInformationItem2(a)-DesignBasisFloodHazards Describe the design basis flood hazard level(s) for all floodcausing mechanisms, including groundwater ingress.

The CPS design basis for external flooding is described in CPS USAR Sections 2.4 and 3.4. CPS is designedtobeprotectedfromtheeffectsoflakefloodingandLIPevent.InadditionCPSisdesignedto beprotectedagainstgroundwateringress.

Thecoolinglakeisdesignedtowithstandtheeffectsofaprobablemaximumstormoccurringoverthe entiredrainagebasinabovethedamsite.IntheSaltCreekbasin,therearenoexistingorproposed dams upstream from CPS; therefore flood waves induced from dam failures that affect the safety relatedstructureswereconsideredirrelevantinthedesignbasisfloodingevaluation.Massivelandslide fromthevalleywallsintothecoolinglakecausedbyaseismicdisturbancewasnotconsideredbecause oflackofsusceptibletopographicandgeologicalfeatures.Givenitsproximityawayfromcoastalareas, flooding due to tsunami was not considered at CPS. Therefore, the governing design basis PMF conditionishighwaterinthelake.Allthesafetyrelatedstructuresareprotectedagainstthisevent.

(USARSection2.4.2.2)

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ThedesignbasisPMFlakestillwaterlevelforCPSiselevation708.9feet.Superimposingthewindwave effectduetoasustained40mphwindactingontheprobablemaximumwaterlevelwillresultinwave runup elevations of 711.9 feet and 713.8 feet for significant waves and maximum (1%) waves, respectively,atthestationsite.Forpurposesofthestationwalkdownsperformedforthisreport,the PMFistakenas713.8feet.ThiselevationisapplicabletotheCirculatingWaterScreenHouseSXpump rooms.Theseroomsaredesignedtobefloodprotectedtoelevation714feet.(USARSections2.4.2.2 and2.4.10)

CPSmainpowerblockbuildingsaresituatedatgradeelevation736feet,wellabovethePMFlevel.The portionsofthebuildingsubstructureslocatedbelowthemaximumgroundwaterlevelaredesignedto prevent groundwater ingress. Per the licensing basis, the groundwater table at the CPS site is conservativelytakenaselevation730feet.Allsubstructuresbelowelevation730feetattheCPSsite aredesignedtowithstandfullhydrostaticheadofgroundwater.(USARSection2.4.2.3)

LIPhasbeendeterminedtoresultinamaximumwatersurfaceelevationof736.8feetintheimmediate station area where safetyrelated facilities are located (southern half of the main power block structure). The analysis assumes that local surface drainage systems do not function during the LIP event.Theareassurroundingtheplantaregradedtodirectsurfacerunoffawayfromtheplant.The stationfloorelevationisatelevation737feetandexteriorpowerblockwallsaredesignedtobeflood barriersto737feet.Thedesignbasiswaterelevationattheexteriorpowerblockwallsis736.8feet, exceptwherethewallsareadjacenttotheUnit2excavation,asdescribedbelow.Thenorthernhalfof the main power block structure contains no below grade safetyrelated equipment. Ponding on the northern side of the plant over portions enclosed by curved railroad tracks is estimated to be at elevation737.2feet.Thebuildingfloordrainsystemwouldtakecareofanywaterthatmightenterthe building.(USARSection2.4.2.3)

FortheUnit2excavationithasbeenconservativelyestimatedinthelicensingbasisthatduringthe48 hourPMPevent,withoutconsideringtheprotectingeffectofthesurroundingearthbermsandwithout thebenefitofanydrainageoutoftheexcavation,theelevationoftheimpoundedrainwaterrunoffwill be 728 feet. For purposes of the station walkdown and this report the water level in the Unit 2 excavationistakenas728feet.(USARSection2.4.2.3)

USARSection2.4addressesadditionalfloodingmechanismsthatareeithernotcriticalornotbounding forCPS.ProbablemaximumsurgeandseichefloodingisnotboundingforCPSbecausethereisnolarge bodyofwaternearthesitewheresignificantstormsurgesandseicheformationscanoccur.Thesizeof thecoolinglakeisnotlargeenoughtodevelopasurgeorseichefloodingcondition.Thestationwillnot besubjectedtotheeffectsoftsunamifloodingbecausethesiteisnotadjacenttoacoastalarea.The effects of the PMF on the lake water level resulting from ice formation are less than that of the probablemaximumsummerflood.

b. RequestedInformationItem2(b)-CLBProtectionandMitigationFeatures Describeprotectionandmitigationfeaturesthatareconsideredinthelicensingbasisevaluationtoprotect againstexternalingressofwaterintoSSCsimportanttosafety.

TheonlysafetyrelatedequipmentatClintonPowerStationthatcouldbedirectlyimpactedbyflooding of the Salt Creek and Clinton Lake are the SX pumps and associated equipment. These pumps are

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installedinwatertightcompartmentsintheCirculatingWaterScreenHouse.Thewallsoftheserooms aredesignedtobefloodprotectedtoelevation714feet.PMFlevelis708.9feet.Superimposingthe windwaveeffectwillresultinamaximumwaverunupelevationof713.8feet.Hatchesareprovidedon theroofoftheessentialservicewaterpumpstructure(elevation730feet)foraccesstoeachoftheSX pumproomsduringPMF.(USARSections2.4.2.2and2.4.10)

Withinthemainpowerblockstructures,thereissafetyrelatedequipmentlocatedbelowgradeinthe Auxiliary,Containment,Fuel,ControlandDieselGeneratorbuildings.Nosafetyrelatedequipmentis locatedbelowgradeintheTurbineorRadwastebuildings.TheportionoftheContainmentBuilding located at and below grade is enclosed by the Auxiliary and Fuel buildings. Consequently, the ContainmentBuildinghasnoexteriorwallsbelowgrade.Allofthebuildingswithexteriorwallsbelow grade,includingtheTurbineandRadwastebuildings,aredesignedtobewatertightuptoplantfloor elevation737feet,whichisabovethegradeelevation736feet.Potentialsourcesofexternalflooding ofthemainpowerblockbuildingsareLIPandgroundwateringress.Fordesignpurposesandperthe licensingbases,thegroundwatertableattheCPSsiteisconservativelytakenaselevation730feet.All substructuresbelowelevation730feetattheCPSsitearedesignedtowithstandfullhydrostatichead ofgroundwater.LIPhasbeendeterminedtoresultinamaximumwatersurfaceelevationof736.8feet intheimmediatestationareawheresafetyrelatedfacilitiesarelocated(Auxiliary,Fuel,Controland DieselGeneratorbuildings).LocalsurfacedrainagesystemsareassumednottofunctionduringtheLIP event.Theareassurroundingtheplantaregradedtodirectsurfacerunoffawayfromtheplant.The stationfloorisatelevation737feetandexteriorpowerblockwallsaredesignedtobefloodbarriersto 737 feet. Ponding on the northern side the Turbine and Radwaste buildings is estimated to be at elevation737.2feet.Thebuildingfloordrainsystemwouldtakecareofanywaterthatmightenterthe building.(USARSection2.4.2.3)

Ingeneral,allfloodprotectionfeaturesatCPSthataredesignedtoprotectsafetyrelatedequipment arepassiveincorporatedfeatures.TheonlyactivefeaturesarethesumppumpsintheSXpumprooms and the roof hatches for access to these rooms during a flood. The sump pumps are not explicitly creditedinthelicensingbasis,butwouldservetoprotecttheSXpumpsshouldasmallamountofwater leakintotheSXpumprooms.Onepassivetemporaryfloodprotectionfeaturewasidentified;thefloor hatchintheSXBpumproom.ProcedureCPS4303.02requiresinstallationofthishatchintheevent ofhighlakewaterlevel(elevation694ft.)andleakageintotheSXpipetunnel.TheCPSprocedurealso requires sandbagging at the CirculatingWater Screen House in the event of flooding,however, this actionisdesignedtoprovideprotectionforthenonsafetyrelatedcirculatingwaterpumpmotorsand othernonsafetyrelatedplantassets.Reasonablesimulationofthisactionwasthereforeconsidered outsidethescopeofthiseffort.

ThefloodprotectionfeaturesatCPSaredesignedsuchthattheireffectivenessisnotdependenton concurrentweatherconditionsoronfloodingduration.Inaddition,CPSfloodprotectionfeaturesare designedtofunctionduringanyplantmodeofoperation.

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c. RequestedInformationItem2(c)-FloodWarningSystems Describeanywarningsystemstodetectthepresenceofwaterinroomsimportanttosafety.

CPShasnowarningsystemsinroomsimportanttosafetycreditedtodetectfloodingfromexternal sources. While not credited for detection of external flooding, each of the SX pump rooms in the CirculatingWaterScreenHouseisequippedwithalevelswitchintheroomsumpwhichwillalarmif highwaterlevelisdetected.Similarly,sumpsineachofthemainpowerblockbuildingswillalarmif highwaterlevelisdetected.

d. RequestedInformationItem2(d)-FloodProtectionSystem/BarrierEffectiveness Discuss the effectiveness of flood protection systems and exterior, incorporated, and temporary flood barriers.Discusshowthesesystemsandbarrierswereevaluatedusingtheacceptancecriteriadevelopedas partofRequestedInformationItem1.h[inEnclosure4oftheMarch12,2012,50.54(f)letter]

Section6ofNEI1207definesacceptanceas:

Flood protection features are considered acceptable if no conditions adverse to quality were identified during walkdowns, verification activities, or program reviews as determined by the licenseesCorrectiveActionProgram.Conditionsadversetoqualityarethosethatpreventtheflood protection feature from performing its credited function during a design basis external flooding event and are deficiencies. Deficiencies must be reported to the NRC in the response to the 50.54(f)letter.

AsindicatedinSection3d,inspectionguidancewasdeveloped,supplementingNEI1207,toprovide morespecificcriteriaforjudgingacceptance.Allobservationsthatcouldnotbeimmediatelyjudgedas acceptablewereenteredintoCAPwhereanevaluationoftheobservationcanbemade.

Thepurposeofthewalkdowns,performedinresponsetotheNRCRequestforInformationregarding NTTFRecommendation2.3,istoverifyconformancewiththeCPScurrentlicensingbasis.Theadequacy ofthecurrentlicensingbasiswillbeaddressedinresponsetoRecommendation2.1.

Acceptancecriteriaforvisualinspectionsperformedduringthewalkdownsweredevelopedtoensure thatanyconditionsadversetoqualitywereidentified.Considerationstakenintoaccountwhenflood protectionfeatureswerereviewedincludedthefollowing:

Floodprotectionconfigurationisinaccordancewithdesigndrawingsandthestationcurrent licensingbasis.

Visualinspectiondidnotidentifyanymaterialdegradation.Adetailedlistingofacceptance criteriaforvisualinspectionswasutilizedbythewalkdownteamduringperformanceofthe walkdowns.

Whenapplicable,PMsorperiodicinspectionsareinplace,withintheirrequiredperiodicity,and ofadequatescope.

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Notopographychanges,includingsecuritybarrierinstallations,adverselyaffectthesite drainage.

Walkdownswereconductedtoverifytheexteriorwallsandfloorscreditedforkeepingwateroutof safetyrelatedareasarecapableofperformingtheirintendedfunctionbasedonvisualobservations.In addition,penetrationsthroughthesewallsandfloorswereinspectedtoverifytheircondition.Flood protectionfeaturesinspectedatCPSalsoincludedflooddoorstotheSXpumprooms,thesumppumps intheSXpumproomsandtheroofhatchesforaccesstotheSXpumproomsduringaflood.Anoutdoor walkdownwasconductedtoensurenotopographychangesoraddedstructuresorsecuritybarriers affectsitedrainageasdescribedintheCLB.Whetherconduitsfrommanholesorcable vaultscould provideapathforgroundwaterorrainwatertoentersafetyrelatedbuildingswasconsideredrelative tothewalkdownscope.Conduitsfrommanholes/cablevaultsgenerallyarenotroutedtosafetyrelated buildingsatCPS.Inafewcasesthereareenteringconduitsthatturnupwardsandterminateabove gradelevelsuchthatnopathforwaterisprovided.Thewalkdownscopeincludedinspectionsofthe externalconduitseals.Internalconduitsealscouldnotbevisuallyinspectedbutareprovidedbydesign.

Evidenceofgroundwater/rainwaterleakagethroughconduitsintosafetyrelatedbuildingsatCPSwas notidentifiedduringthewalkdowns.ConduitsatCPSdonotprovideapathforgroundwaterorrain watertoentersafetyrelatedbuildings.

Thewalkdowns,simulations,anddocumentreviewsverifythatfloodprotectionfeaturesincorporated intheCPSdesignprovideeffectivebarriersforkeepingexternalfloodingfromreachingsafetyrelated systemsandequipment.TheSXpumproomsintheCirculatingWaterScreenHousewillprovideflood protectionfromPMFlevelfloodingofthelake.Theexteriorwallsofthemainpowerblockbuildings preventingressofgroundwater.Thefloorelevationatthemainpowerblockbuildingsiselevatedabove grade to prevent water from local intense precipitation from entering safety related buildings. No topography changes or new security barriers will prevent drainage following a LIP event. The walkdowns,simulations,anddocumentreviewsdid,however,resultinsomeobservationsthatcould notbeimmediatelyjudgedasacceptable.ThesewereenteredintoCAPfordisposition.

Inadditiontothesewalkdowns,thestationstructuralmonitoringprogram(References14and15)and preventativemaintenanceactivitiesasreferencedintheindividualwalkdownpackagerecordsprovide forongoingverificationoffloodbarriereffectiveness.

e. RequestedInformationItem2(e)-ImplementationofWalkdownProcess Presentinformationrelatedtotheimplementationofthewalkdownprocess(e.g.,detailsofselectionof the walkdown team and procedures) using the documentation template discussed in Requested Information Item 1.j [in Enclosure 4 of the March 12, 2012, 50.54(f) letter], including actions taken in responsetothepeerreview.

StationwalkdownswereimplementedinaccordancewiththeguidelinesprovidedinNEI1207.TheCPS walkdown team included three Sargent & Lundy employees as well as the CPS Lead Responsible Engineerforfloodingissues.Allteammemberswerefamiliarwiththestationlicensingbasisrelativeto external flooding and have completed both NANTeL based training and Exelon specific training on implementationoftheNEI1207guidelines.TheSargent&Lundyteamconsistedoftwomechanical

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engineersfamiliarwithClintonPowerStationandonecivilengineerwithexperienceinsitedrainage issues. At least two Sargent & Lundy team members performed all visual inspections. Walkdown resultsweredocumentedusingtheNEI1207recommendedform.Walkdownpackages,oneforeach feature, were prepared in advance and included the NEI 1207 walkdown form, with Parts A and B already completed, as well as reference drawings and documentation. The remaining parts of the walkdown forms were finalized after the feature walkdown was completed, and the identified observationswereenteredinCAP.

f. RequestedInformationItem2(f)-FindingsandCorrectiveActionsTaken/Planned Resultsofthewalkdownincludingkeyfindingsandidentifieddegraded,nonconforming,orunanalyzed conditions.Includeadetaileddescriptionoftheactionstakenorplannedtoaddresstheseconditionsusing theguidanceinRegulatoryIssuesSummary200520,Rev1,RevisiontoNRCInspectionManualPart9900 TechnicalGuidance,OperabilityConditionsAdversetoQualityorSafety,includingenteringthecondition inthecorrectiveactionprogram.

Thewalkdownscopewasdevelopedtoconfirmthatfloodprotectionfeaturescreditedinthecurrent licensingbasisareacceptableandcapableofperformingtheircreditedfloodprotectionfunctions.For CPSthescopeprimarilyconsistedofvisualinspectionsoffloorsandexteriorwatertightwallsbothinthe SXpumproomsandinthemainpowerblock.The scopeincludedvisualinspectionofallapplicable penetrationsandwatertightdoors.Inaddition,anoutdoorwalkdownwasconductedtoconfirmsurface drainage provisions have not been impacted by changes to topography, such as might result from installationofnewsecuritybarriers.Inspectionsofcreditedwalkdownfeatureswereperformedbythe walkdown team following the guidance provided in NEI 1207 and were documented in walkdown packages using the NEI 1207 walkdown forms. Walkdown record forms are retained on site as discussedinSection7ofReference2.Wheredegraded,nonconformingorunanalyzedconditionswere identified,thesefindingsweredocumentedandenteredintoCAP.

Theinspectionsofwalls,floorsandpenetrations/sealsverifiedthatcreditedfloodbarriersareinplace andappearcapableofperformingtheirintendedfloodprotectionfunction,however,someIRswere generatedandenteredintotheCAP.Thesehavebeenaddressedandarenotreportabledeficiencies.

Tworeasonablesimulationswereconducted.Thefirstwasanexercisetoinstallthewatertightfloor hatchintheSXBpumproom,todemonstratetheCPSprocedurecouldbeimplementedintheevent ofhighlakewaterlevel.Installationofthehatchwasdemonstratedsuccessfully.Issuesrelativetothe hatchwereidentifiedduringthevisualinspectionwalkdownandwereaddressedasdescribedbelow.

CorrespondingIRswereenteredintoCAPandaddressed.Theseissuesarenotreportabledeficiencies.

ThesecondsimulationdemonstratedthattheprocessofopeningtheSXpumproomroofhatchescan beperformedduringaPMFifrequired.

Atotalof17IRsweregeneratedintheprocessofperformingthewalkdowns.Thesearesummarized below and are listed, along with the resolution status, in Table 2 in the Conclusions section of this report.

ObservationsNotImmediatelyJudgedasAcceptable The SX B pump room at the Circulating Water Screen House is equipped with a floor hatch at elevation699ft.toprovideaccesstotheSXtunnelunderneath.Thehatchcoverisnotinstalledandhas beenstoredinanotherroominthebuilding.Thewatertighthatchmustbeinstalledpriortolakelevel

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reaching 699 ft. to prevent flooding of the SX B pump room. Procedure CPS 4303.02 requires monitoring of the SX tunnel for leakage when the lake water level reaches 694 ft. and requires installationofthehatchcoverwhenleakageisnoted.Thewalkdownteaminspectedthehatchopening, inspectedthehatchcoverandwitnessedasimulationduringwhichthehatchcoverwasinstalled.A numberofissueswereidentifiedasaresult.AnexistingIR01197998addressedthestoragelocationof thehatchcover.IR01404215recommendedprotectingtheboltholesinthefloorfromcorrosionand debrisandotherimprovementstofacilitatefutureinstallation,andIR01405906initiatedreplacement ofthehatchcovergasket,asitsconditionwasdegraded.Thehatchcoverhasnowbeenrelocatedandis stored in the SX B pump room near the opening (EC 390374, Reference 18). Handles have been attached to the hatch to facilitate safe installation and removal (EC 390417, Reference 19).

Improvementsmadeincludefabricationofanewgasketforthehatchcover,stagingthisgasketwith the hatch cover, cleaning out of the bolt holes, and verifying proper thread engagement of the bolts/bolt holes. Other minor enhancements to be completed include working the hatch cover bolt holestoimprovealignmentwiththefloorboltholes,installthegasketattheflooropening,andprovide aprotectivecoveroverthegasketandboltholes.

IR 01404339 documents a minor gouge in the sealant material in one of the SX A pump room penetrationseals.Thisconditionwasdeterminednottoimpactthefloodprotectionfunctionofthe seal.

IR01403121documentstheneedtoupdatetheUSARdescriptionofdrainageinthevicinityoftherail road tracks on the north side of the plant. Some of the tracks have been removed. The asbuilt conditionimprovesdrainageinthevicinityandthusdoesnotadverselyimpactcalculatedfloodingdue tolocalintenseprecipitation.

EachoftheSXpumproomsattheCirculatingWaterScreenHouseisequippedwithapersonnelaccess hatchintherooftoprovideaccessduringaflood.ThesehatchesarelocatedwellabovethePMFlevel.

Their flood function is to be opened in the event access is required and normal access doors are flooded. These hatches are built into the building roof. Demonstration of hatch removal to provide access would damage the roof. IRs 01404493 and 01423001 were generated concluding that a simulationwouldbeconductedtoverifytheroofhatchescouldbeopenedifrequired.Thissimulation wassuccessfullyperformedunderWO1553183.Theresultsdocumentthattheroofhatchescouldbe openedinanacceptableperiodoftime(lessthan2hours)withavailablestationresourcesbeforewater reachesPMFlevel.

Performanceofthewalkdownsandsimulationsprovidedconfirmationthatfloodprotectionfeaturesat CPSareinplace,areingoodcondition(exceptasnotedabove)andwillperformascreditedinthe current licensing basis. Observations not immediately judged as acceptable were addressed and dispositionedundertheCAPprogram.

ObservationsDesignatedthroughCAPasDeficient None.

ObservationsAwaitingFinalDispositioninCAP None.

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RestrictedAccessAreas InspectionofthecondenserpitfloorareaintheTurbineBuildingwasdeferreduntilanoutageasdose inthisareaissignificantlyreducedwhentheplantisnotoperating.ThisisdocumentedinIR01407573.

ThenextrefuelingoutageatCPSiscurrentlyscheduledforOctober2013.Reasonableassurancethat thisportionofthefloorisacceptableduringtheinterimisbasedonthefactthatvisualinspectionofthe floor in the remainder of the turbine building revealed no deficiencies or degradation that would preventperformanceofitsfloodprotectionfunction.

InaccessibleAreas A small portion of the total floor andwall areas and a small portion of the penetrations within the walkdownscopeweredeemedinaccessibleandwerenotinspected.Thesefeaturesareinlockedhigh radiationareasorwerephysicallyinaccessible(buriedorblockedfromvisualinspectionbyanelectrical junction box or other obstruction). The inaccessible features are documented in IRs 01405838, 01405843,01407623,01405862,01405858,01405864,01405866,01405880,01405872and01407747.

Reasonableassurancethattheinaccessibleportionsofthewallsandfloorsareacceptableisbasedon the fact that visual inspection of the walls and floors in these buildings and throughout the plant revealednodeficienciesordegradationthatwouldpreventperformanceoffloodprotectionfunction.

Reasonableassurancethatthesepenetrationsareacceptableisbasedonthefactthatvisualinspection revealednosignsofcurrentorpastgroundwaterleakagethroughthesepenetrationsandinspectionsof similar penetrations in these buildings that are sealed from the inside did not show signs of seal degradationthatwouldpreventperformanceoffloodprotectionfunctions.

g. RequestedInformationItem2(g)-Cliff-EdgeEffectsandAvailablePhysicalMargin Documentanycliffedgeeffectsidentifiedandtheassociatedbasis.Indicatethosethatwereenteredinto the corrective action program. Also include a detailed description of the actions taken or planned to addresstheseeffects.

Cliffedge effects were defined in the NTTF Report (Reference 5) as the safety consequences of a floodingeventmayincreasesharplywithasmallincreaseinthefloodinglevel.AsindicatedinSections 3.12ofNEI1207,theNRCisnolongerexpectingtheRecommendation2.3:FloodingWalkdownsto includeanevaluationofcliffedgeeffects.TheNRCisnowdifferentiatingbetweencliffedgeeffects, whichareaddressedinEnclosure2ofReference3,andAvailablePhysicalMargin(APM).

AsindicatedinSections3.13ofNEI1207,APMdescribesthefloodmarginavailableforapplicableflood protectionfeaturesatasite(notallfloodprotectionfeatureshaveAPMs).TheAPMforeachapplicable floodprotectionfeatureisthedifferencebetweenlicensingbasisfloodheightandthefloodheightat whichwatercouldaffectanSSCimportanttosafety.

Whereapplicable,APMinformationwascollectedduringthewalkdownsinaccordancewithguidance providedinNEI1207andthefinalresolutiontoFAQ006.APMwascollectedtoprimarilysupportthe responsetoEnclosure2ofReference3and,assuch,isnotincludedinthisreport.APMdeterminations did not involve calculating cliffedge effects (i.e. the safety consequences). During the Integrated Assessment(seeEnclosure2ofReference3),thecliffedgeeffectsandtheassociatedsafetyriskswill

NTTFRecommendation2.3(Walkdowns):Flooding ClintonPowerStation ExelonCorporation November9,2012 Revision1

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beevaluatedusingtheAPMsandotherinformation,suchasthespecificSSCsthataresubjectedto floodingandthepotentialavailabilityofothersystemstomitigatetherisk.

SincethewalkdownswerecompletedpriortothefinalresolutionofFAQ006(September13,2012),

APM information was collected and documented on the Walkdown Record Form using the old approach;thatis,asimplemeasurementofthedifferencebetweenthelicensingbasisfloodheight andthefloodheightatwhichwatercouldaffectanSSCimportanttosafety.

h. RequestedInformationItem2(h)-Planned/NewlyInstalledFloodProtection Enhancements Describe any other planned or newly installed flood protection systems or flood mitigation measures including flood barriers that further enhance the flood protection. Identify results and any subsequent actionstakeninresponsetothepeerreview.

EnhancementstotheSXpumproomfloorhatchwereimplementedasdescribedintheresponseto Item2(f).Nootherplannedornewlyinstalledfloodprotectionenhancementsweredeterminedtobe necessaryasaresultofthefloodwalkdownsatCPS.

5. CONCLUSIONS Visual inspections of walls, floors and penetrations provided reasonable assurance that credited flood barriers are capable of performing their intended function. All IRs entered into the CAP have been addressedandarenotreportabledeficiencies.Areasonablesimulationwasconductedanddemonstrated thattheinstallationoftheSXpumproomfloorhatchcanbeperformedsuccessfully.Enhancementstothe SXpumproomfloorhatchwereimplementedasdescribedintheresponsetoItem2(f).Nootherchanges weredeterminednecessaryasaresultofthefloodwalkdownsatCPS.Performanceofanexercisetoopen theSXpumproomroofhatcheswasnotcompleted,asdemonstrationofhatchremovalwoulddamagethe roof;asimulationofthisprocesswassubsequentlysuccessfullyperformed.

Asmallportionofthetotalfloorandwallareaswithinthewalkdownscopeweredeemedinaccessibleand were not inspected. Reasonable assurance that these portions of the walls and floors are acceptable is based on the fact that visual inspection of the walls, floors and penetrations in these buildings and throughout the plant revealed no deficiencies or degradation that would prevent performance of flood protectionfunctions.InspectionofthecondenserpitfloorareaintheTurbineBuildingwasdeferreduntil theOctober2013outageasdoseinthisareaissignificantlyreducedwhentheplantisnotoperating.

Nooperabilityissueswereidentifiedandnodegraded,nonconformingorunanalyzedconditionsrequire performanceofadditionalactions.

Table1providesasummaryofthenumberandtypeoffeaturesincludedinthewalkdownscope.

Table2providesthelistoftheIRsgeneratedandenteredintothestationcorrectiveactionprogram(CAP) asaresultofthewalkdown.ThestatusofeachIRatthetimeofthisreportisindicated.NoneoftheseIRs resultedinanoperabilityconcernandnonearereportabledeficiencies.

NTTFRecommendation2.3(Walkdowns):Flooding ClintonPowerStation ExelonCorporation November9,2012 Revision1

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Table1:FeaturesIncludedintheWalkdownScope Type

  1. ofVisual Inspections
  1. ofSimulations, DrillsorExercises Incorporated/ExteriorPassive 39 0

Incorporated/ExteriorActive 9

3*

TemporaryPassive 1

1 TemporaryActive 0

0 Totals 49 1

  • One(1)simulationwasperformedtoaddressthese3features.

Table2:IRsGeneratedinCAP IRNumber Description ProposedResolution Status/Resolution 01405838 RHRBroomfloorinaccessible Accesswassubsequentlygranted androominspectioncompleted Closeasis.

01405843 InaccessiblepenetrationsinAux Buildingwestwall Evaluateandprovidejustification foracceptance Reasonableassurance providedthatfeaturewill performasdesigned.

01407623 InaccessiblepenetrationsinDiesel Buildingsouthwall Evaluateandprovidejustification foracceptance Reasonableassurance providedthatfeaturewill performasdesigned.

01405862 InaccessiblefloorareasinFuel Building Evaluateandprovidejustification foracceptance Reasonableassurance providedthatfeaturewill performasdesigned.

01405858 InaccessiblepenetrationsinFuel Buildingeastwall Evaluateandprovidejustification foracceptance Reasonableassurance providedthatfeaturewill performasdesigned.

01405864 InaccessiblepenetrationsinFuel Buildingsouthwall Evaluateandprovidejustification foracceptance Reasonableassurance providedthatfeaturewill performasdesigned.

01405866 InaccessiblepenetrationsinFuel Buildingwestwall Evaluateandprovidejustification foracceptance Reasonableassurance providedthatfeaturewill performasdesigned.

01403121 USARSection2.4.2.3description requiresupdateregardingcurved railroadtracksnorthofplant.Tracks havebeenremoved.

InitiateUSARchangepackage StatementinUSARwillbe updated.

01405880 InaccessibleroomfloorsinRadwaste Building Evaluateandprovidejustification foracceptance Reasonableassurance providedthatfeaturewill performasdesigned.

01405872 Inaccessiblepenetrationsin RadwasteBuildingnorthwall Evaluateandprovidejustification foracceptance Reasonableassurance providedthatfeaturewill performasdesigned.

NTTFRecommendation2.3(Walkdowns):Flooding ClintonPowerStation ExelonCorporation November9,2012 Revision1

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IRNumber Description ProposedResolution Status/Resolution 01404493 DeferredSXpumproomsimulation asopeninghatchdamagesroof Scheduleopeningofroofhatches tocorrespondwithplannedroof replacementorevaluatedand providejustificationfor acceptance ClosetoIR01423001 01423001 OpeningofSXpumproomroof hatchesnottobeperformed.

Reclassifyasinaccessible PerformsimulationtoopenDiv.3 SXpumproomhatch Simulationwasperformed underWO01553183task 14.

01404339 SmalllossofBiscomaterialinSX roompenetrationseal Evaluateandprovidejustification foracceptance Reasonableassurance providedthatfeaturewill performasdesigned.

01405906 GasketinSXroomfloorhatchis degraded.

ReplacegasketinSXroomfloor hatch WorkOrder01431449 replacedgasket.

01404215 IssueswithSXroomfloorhatch installation ProtectboltholeswithFMEcover, improvehatchstorage,enhance hatchinstallationprocedure WorkOrder01431449will implementenhancements 01407747 CondensatepolisherroomG,H&J inaccessible Evaluateandprovidejustification foracceptance Reasonableassurance providedthatfeaturewill performasdesigned.

01407573 Deferredcondenserpitfloor inspection Inspectduringstationoutage whenareadoseratesarelow Reasonableassurance providedthatfeaturewill performasdesigned.SCRF#

5802tracksdeferral.

6. REFERENCES
1. ExelonLettertoU.S.NuclearRegulatoryCommission.ExelonGenerationCompany,LLCs90Day ResponsetoMarch12,2012RequestforInformationPursuanttoTitle10oftheCodeofFederal Regulations50.54(f)RegardingRecommendations2.1and2.3,oftheNearTermTaskForceReview ofInsightsfromtheFukushimaDaiichiAccident(Flooding).June11,2012.
2. Nuclear Energy Institute (NEI), Report 1207 [Rev 0A]. Guidelines for Performing Verification WalkdownsofPlantProtectionFeatures.May2012[NRCendorsedMay31,2012;updatedandre issuedJune18,2012].
3. U.S.NuclearRegulatoryCommission.LettertoLicensees.RequestforInformationPursuanttoTitle 10oftheCodeofFederalRegulations50.54(f)RegardingRecommendations2.1,2.3,and9.3ofthe NearTermTaskForceReviewofInsightsfromtheFukushimaDaiichiAccident.March12,2012.
4. U.S. Nuclear Regulatory Commission. Demonstrating the Feasibility and Reliability of Operator ManualActionsinResponsetoFire.NUREG1852.October2007.
5. U.S.NuclearRegulatoryCommission.RecommendationsforEnhancingReactorSafetyinthe21st Century,TheNearTermTaskForceReviewofInsightsfromtheFukushimaDaiichiAccident.July12, 2011.
6. U.S.NuclearRegulatoryCommission.OperabilityDeterminations&FunctionalityAssessmentsfor ResolutionofDegradedorNonconformingConditionsAdversetoQualityorSafety.NRCInspection

NTTFRecommendation2.3(Walkdowns):Flooding ClintonPowerStation ExelonCorporation November9,2012 Revision1

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Manual. Part 9900: Technical Guidance. Regulatory Issues Summary 200520, Revisions 1.

September26,2005.

7. InstituteofNuclearPowerOperations.FukushimaDaiichiNuclearStationFuelDamageCausedby EarthquakeandTsunami.INPOEventReport111.March15,2011.
8. U.S. Nuclear Regulatory Commission. Followup to the Fukushima Daiichi Nuclear Station Fuel Damage Event. Inspection Manual. Temporary Instruction 2515/183. ML113220407. November 2011.
9. U.S. Nuclear Regulatory Commission. Inspection of Structures, Passive Components, and Civil Engineering Features at Nuclear Power Plants. Inspection Manual. Inspection Procedure 62002.

Section03.01(h),Dams,EmbankmentsandCanals.

10. U.S.NuclearRegulatoryCommission.EvaluateReadinesstoCopewithExternalFlooding.Inspection Procedures.Attachment71111.01.AdverseWeatherProtection.Section02.04.
11. U.S.NuclearRegulatoryCommission.NRCInspectorFieldObservationBestPractices.NUREG/BR 0326,Rev.1.August2009.
12. U.S.NuclearRegulatoryCommission.FloodProtectionforNuclearPowerPlants.RegulatoryGuide 1.102.
13. CPSUSAR,Rev.14
14. ProcedureERAA450,Rev.1,StructuresMonitoring
15. ProcedureERCL4501006,Rev.1,ClintonStructuresMonitoringInstructions
16. SupplementalWalkdown/InspectionGuidance,Rev.1,August17,2012
17. ProcedureCPS4303.02,Rev.10a,AbnormalLakeLevel
18. EC390374,StagingLocationfortheDiv2PumpRoomHatchCoverat699
19. EC390417,FabricationInstallationofHandlesontheDivisionIISXPumpRoomAccessHatchCover

U.S. Nuclear Regulatory Commission 180-Day Response to 50.54(f) Letter NTTF Recommendation 2.3: Flooding November 27, 2012 Page 4

SUMMARY

OF REGULATORY COMMITMENTS The following table identifies commitments made in this document. (Any other actions discussed in the submittal represent intended or planned actions. They are described to the NRC for the NRCs information and are not regulatory commitments.)

COMMITMENT TYPE COMMITMENT COMMITTED DATE OR "OUTAGE" ONE-TIME ACTION (Yes/No)

PROGRAMMATIC (Yes/No)

Exelon Generation Company, LLC (EGC) will complete the inspection of Clinton Power Station condenser pit floor area in the Turbine Building, classified as restricted access and deferred due to inaccessibility.

C1R14 Winter 2013 Yes No

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