ML15204A323

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Waterford, Unit 3 - Attachment 2 to WF3-CS-15-00010, Rev. 0, Document 51-9227040-000, Fukushima Flood Hazard Reevaluation Report, Pp. 1 Through 3-61
ML15204A323
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Site: Waterford Entergy icon.png
Issue date: 07/21/2015
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AREVA
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Document Control Desk, Office of Nuclear Reactor Regulation
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ML15204A344 List:
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W3F1-2015-0042 51-9227040-000, WF3-CS-15-00010, Rev. 0
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{{#Wiki_filter:Attachment 2 toW3F1 -2015-0042Page 1 of 265Attachment 2 toW3FI -2015-0042Flood Hazard Reevaluation Report(264 pages) ATTACHMENT 9.1ENGINEERING REPORT COVER SHEET & INSTRUCTIONSATTACHMENT 9.1 ENGiNEERING REPORT COVER SHEET & INSTRUCTIONSEngineering Report No. WF3-CS-15-00010 Rev 0Page 1 of 264ENTERGY NUCLEAREngineering Report Cover SheetEngineering Report Title:Waterford Steam Electric Station Unit 3 Fukushima Flood Hazard Re-evaluation ReportEngineering Report Type:New [] Revision [] Cancelled [] Superseded [SSuperseded by: __________Applicable Site(s)IP1 ElANOl ElEC No. 58788iP2 ElAN02 El1P3 ElECH ElJAF ElGGNS ElPNPS ElRBS []vyD[PLP ![--Report Origin:LI Entergy [] VendorVendor Document No.: 51-9227040-00Quality-Related: [] YesARE VA / See AREVA Cover Pages[] NoPrepared by:Design Verified:Reviewed by:Approved by:Responsible Engineer (Print Name/Sign)ARE VA / See ARE VA Cover PagesDesign Verifier (if required) (Print Name/Sign)Stephen Picard I See Associated ECDate: 7/9/15Date: 7/9/15Date: 7/13/15Date: 7/13/15Reviewer (Print Name/Sign)Chris Talazac / See Associated ECSupervisor / Manager (Print Name/Sign)EN-DC-147 REV 6 A20004-021 (01/30/2014)ARE VAAREVA Inc.Engineering Information Record51Document No.:-9227040 -000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportPage 1 of 263 ARE VA20004-021 (0 1/3012014)Document No.: 61-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportSafety Related? [J YES liNODoes this document establish design or technical requirements? L---YES I] NODoes this document contain assumptions requiring verification? [j YES Does this document contain Customer Required Format? -NOSignature Blocki[ ........PegealSectionsName and PILP, R/LR, Pr-epared/ReviewedlTitlelDlseipline , _A.CRF, A Date Approved or CommentsDanielsc tsT.ivBrown LP 7if" Al!l -EnvironmentalAnalys~is ,____...___,...Kenneth D. Hturu " 'Secains 3.1. 3.2, 3.3, 3.4, 3.6, 3.7,"3.8,GzA Civil Enginee an 3.9Advisory Engineer, '/q //.--5Environmental -Analysis______ ___________________Dvd ...." ....one -/' -.... ..-.... Sections 3.1, 3.2, 3.3, 3,4, 3.6, 3.7, 3.5,GMA Hydraulicad39Barbara Hua. AeAllFirst Line Leader,Radiological &"EnvironmentalAnalysis I___________ .. ....___Note: P/LP designates Preparer (P), Lead Preparer (LP)RILR. designates Reviewer (R), Lead Reviewer (LR)A-CRF designates Project Manager Approver of Customer Required Format (A-CRF)A designates ApproverlRTM -Verification of Reviewer IndependenceProject Manager Approval of Customer References (NIA if not applicable)........Page 2 AARE VA20004-021 (01/30/2014)Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportRecord of RevisionRevision Pages/Sections/No. Paragraphs Changed Brief Description / Change Authorization000 All Initial release.Page 3 A 20004-021 (01/30/2014)A R E VA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportOverviewThis report describes the approach, methods, and results from the re-evaluation of flood hazards at the WaterfordSteam Electric Station (WSES). It provides the information, in part, requested by the U.S. Nuclear RegulatoryCommission (NRC) to support the evaluation of the NRC staff recommendations for the Near-Term Task Force(NTTF) review of the accident at the Fukushima Dai-ichi nuclear facility.Section 1.0 provides introductory information related to the flood hazard. The section includes backgroundregulatory information, scope, general method used for the re-evaluation, assumptions, the elevation datum usedthroughout the report, and a conversion table to determine elevations in other common datum.Section 2.0 describes detailed WSES site information, including present-day site layout, topography, and currentlicensing basis flood protection and mitigation features. The section also identifies relevant changes since licenseissuance to the local area and watershed as well as flood protections.Section 3.0 presents the results of the flood hazard re-evaluation. It addresses each of the eight flood-causingmechanisms required by the NRC as well as a combined effect flood. In cases where a mechanism does not applyto the WSES site, a justification is included. The section also provides a basis for inputs1 and assumptions,methods, and models used.Section 4.0 compares the current and re-evaluated flood-causing mechanisms. It provides an assessment of thecurrent licensing and design basis flood elevation to the re-evaluated flood elevation for each applicable flood-causing mechanism evaluated in Section 3.0.Section 5.0 presents an interim evaluation and actions taken, or planned, to address those higher flooding hazardsidentified in Section 4.6J relative to the current licensing and design basis.Section 6.0 describes the additional actions taken to support the interim actions described in Section 5.0. Notethat no additional actions were identified as necessary.The report also contains one appendix. Appendix A background information used to determine the specificelevation differencet for the site datum relative to National Geodetic Survey reference stations.Page 4 A 20004-021 (01/30/2014)A R EVA Document No.: 51-9227040-000Water-ford Steam Electric Station Flooding Hazard Re-Evaluation ReportExecutive SummaryThis report satisfies the "Hazard Reevaluation Report" Request for Information pursuant to 10 Code of FederalRegulations (CFR) 50.54(f) by the NRC dated November 12, 2012, NTTF Recommendation 2.1 FloodingEnclosure 2.The report describes the approach, methods and results from the re-evaluation of flood hazards at Water-fordSteam Electric Station (WSES). This report addresses the eight flood-causing mechanisms and a combined effectflood, identified in Attachment I to Enclosure 2 of the NRC information request. No additional flood causingmechanisms were identified for WSES.Each of the re-evaluated flood causing mechanisms and the potential effects on the WSES site are described inSections 3.0 and 4.0 of this report.The methodology of the flood hazard reevaluation documented in this report follows the Hierarchical HazardAssessment approach, as described in NUREG/CR-7046, "Design-Basis Flood Estimation for SiteCharacterization at Nuclear Power Plants in the United States of America", NRC Interim Staff Guidance, asappropriate, and their supporting reference documents.Screened mec hanisms have been evaluated at a high level and determined to n~ot be applicable to the floodinghazard for WSES.The WSES design basis flood level and associated design basis protections are challenged by two floodmechanisms. The direct precipitation and rooftop drainage during the Local Intense Precipitation event results inponding in the Dry Cooling Tower Basins, with potential to impact equipment important to safety. Additionally,the WSES deoign basis is challenged by flooding due to the combined effects fa combined effect flood scenarioresulting in wave overtopping the east side of the Nuclear Plant Island Structur'e. Interim evaluations of theimpacts of those two flood mechanisms are addressed in Section 5.0.An evaluation was performed to determine the impact of inundation due to the two flood mechanisms thatchallenge the WSES design basis. The results of this evaluation indicate that there are no impacts to equipmentimportant to safety as a result of the re-evaluated flood elevations.Page 5 AA R EVA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportTable of ContentsPageSIGNATURE BLOCK ........................................................................................... 2RECORD OF REVISION ....................................................................................... 3OVERVIEW ..................................................................................................... 4EXECUTIVE SUMMARY....................................................................................... 5LIST OFTABLES ............................................................................................... 9LIST OFFIGURES ............................................................................................ 11ACRONYMS AND ABBREVIATIONS........................................................................ 1

41.0 INTRODUCTION

...................... .............................................................. 1-1S 1.1 Purpose ................................. ...................................................... 1-11.2 Scope ......................................................................................... 1-11.3 Method......................................................................................... 1-11.4 Assumptions.................................................................................. 1-21.5 Elevation Values.............................................................................. 1-2S 1.6 References............................. ....................................................... 1-22.0 INFORMATION RELATED TO THE FLOOD HAZARD............................................ 2-12.1 Detailed Site Information .................................................................... 2-12.1.1 SiteLayout ................................................................................... 2-12.2 Current Design Basis Flood Elevation................................. i..................... 2-12.2.1 Elevation of Safety Structures, Systems and Components ............................... 2-12.3 Current Licensing Basis Flood Protection and Mitigation Features....................... 2-22.3.1 CLB Flood Causing Mechanisms ........................................................... 2-22.4 Licensing Basis Flood-Related and Flood Protection Changes........................... 2-32.5 Watershed and Local Area Changes ....................................................... 2-32.5.1 Watershed Changes ......................................................................... 2-32.5.2 Local Area Changes ......................................................................... 2-32.6 Additional Site Details -Walkdown Results................................................ 2-32.7 References ................................................................................... 2-43.0 FLOOD HAZARD RE-EVALUATION ............................................................... 3-13.1 Local Intense Precipitation .................................................................. 3-23.1.1 Local Intense Precipitation -External to NPIS............................................. 3-23.1.2 Local Intense Precipitation -Internal to NPIS.............................................. 3-53.1.3 Conclusions ................................................................................. 3-183.1.4 References.................................................................................. 3-183.2 Flooding in Rivers and Streams ........................................................... 3-623.2.1 Method ...................................................................................... 3-62Page 6 AA R EVA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportTable of Contents(continued)Page3.2.2 Results......................................................................................... 3-623.2.3 Conclusions ................................................................................... 3-653.2.4 References .................................................................................... 3-653.3 Dam Breaches and Failures ................................................................. 3-713.3.1 Method......................................................................................... 3-713.3.2 Results......................................................................................... 3-723.3.3 Conclusions.................................................................................... 3-733.3.4 References .................................................................................... 3-733.4 Storm Surge................................................................................... 3-813.4.1 Location and Hydrologic Setting..... ........................................................ 3-813.4.2 Methodology................................................................................... 3-823.4.3 Assumptions................................................................................... 3-863.4.4 Results......................................................................................... 3-863.4.5 Conclusions ................................................................................... 3-963.4.6 References ........................ ............................................................ 3-963.5 Seiche........................................................................................ 3-1373.5.1 Seiche Screening Discussion .............................................................. 3-1373.5.2 References................................................................................... 3-1373.6 Tsunamis..................................................................................... 3-1383.6.1 Methodology ................................................................................. 3-1383.6.2 Tsunami Results............................................................................. 3-1383.6.3 Conclusions.................................................................................. 3-1413.6.4 References................................................................................... 3-1423.7 Ice-Induced Flooding........................................................................ 3-1473.7.1 Method ....................................................................................... 3-1473.7.2 Ice-Induced Flooding Results .............................................................. 3-1473.7.3 Conclusions.................................................................................. 3-1473.7.4 References................................................................................... 3-1483.8 Channel Migration or Diversion ............................................................ 3-1493.8.1 Method ....................................................................................... 3-1493.8.2 Results ....................................................................................... 3-1493.8.3 Conclusions.................................................................................. 3-1503.8.4 References................................................................................... 3-1503.9 Combined Effect Flood...................................................................... 3-1513.9.1 Methodology ................................................................................. 3-1513.9.2 Assumptions ................................................................................. 3-1543.9.3 Results ....................................................................................... 3-155Page 7 AA R EVA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportTable of Contents(continued)Page3.9.4 Conclusions................................................................................ 3-1623.9.5 References................................................................................. 3-1624.0 FLOOD PARAMETERS AND COMPARISON WITH CURRENT LICENSING BASIS .......... 4-14.1 Summary of Current Licensing Basis and Flood Reevaluation Results.................. 4-14.2 References ................................................................................... 4-15.0 INTERIM EVALUATION AND ACTIONS TAKEN OR PLANNED................................. 5-15.1 LIP Flooding in DCT Basins.............................. ................................... 5-15.1.1 Potential Impacts of LIP Flooding in DCT Basins................................ 5-15.1.2 Actions Taken Due lto LIP Flooding in DCT Basins.............................. -5.2 Controlling Combined Effect Flooding ...................................................... 5-'15.2.1 Potential Impacts of Controlling Combined Effect Flooding..................... 5-15.2.2 Actions Taken Due to Controlling Combined Effect Flooding................... 5-26.0 ADDITIONAL ACTIONS.............................................................................. 6-1APPENDIX A: ELEVATION DATUM C9NVERSION ................................................. A-I1Page 8 AA R EVA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportList of TablesPageTABLE 3-1: LIP MODEL RESULTS ................................................................ 3-21TABLE 3-2: STORMS USED TO CALCULATE THE SITE-SPECIFIC LIP VALUES........... 3-22TABLE 3-3: POINT (1-MI2) LOCAL INTENSE PRECIPITATION DEPTHS AT WSES ......... 3-23TABLE 3-4: SITE-SPECIFIC PMP RAINFALL DISTRIBUTION.................................. 3-24TABLE 3-5: DCT BASINS SUMMARY OF CONTRIBUTING AREAS ........................... 3-28TABLE 3-6: MSIV AREAS SUMMARY OF CONTRIBUTING AREAS........................... 3-29TABLE 3-7: DCT BASINS STORAGE AREAS SUMMARY....................................... 3-30TABLE 3-8: REACTOR BUILDING ROOF DRAIN CAPACITY (THREE 6-INCH ROOF DRAINS)3-31TABLE 3-9: ONE 3-INCH-DIAMETER SCUPPER CAPACITY.................................. 3-33TABLE 3-10: ONE 4-1NCH-DIAMEh-ER ROOF DRAIN CAPACITY..............................3-434TABLE 3-11: TWO 6-INCH-DIAMETER ROOF DRAINS CAPACITY........................... 3-35TABLE 3-12: MSIV WEST DRAINS CAPACITY (TWO 5-INCH-DIAMETER FLOOR DRAINS)3-36TABLE 3-13: MSIV EAST DRAIN CAPACITY (ONE 4-INCH-AND ONE 5-INCH DIAMETERSCUPPER)................................................................................ 3-37TABE 314 DC BAIN DEPTHS SUMMARY (FT)...................33TABLE 3-15: MSIV AREAS MAXIMUM PONDING DEPTHS SUMMARY ...................... 3-39TABLE 3-16: SUMMARY OF LANDFALL LOCATIONS ........................................ 3-100TABLE 3-17: PMH PARAMETER RANGES FOR WSES .................................. .....3-101TABLE 3-18: TOP 10 EXTREME WATER LEVELS FROM STORM SURGE/ STORM TIDE ALONGTHE U.S. GULF: COAST FROM 1880-2013 FROM SURGEDAT DATABASE... 3-102TABLE 3-19: STERIC WATER LEVEL ADJUSTMENT ......................................... 3-102TABLE 3-20: COMPARISON OF ADCIRC SIMULATED RESULTS AND OBSERVED HIGHWATER MARKS -HURRICANE KATRINA (2005) ................................. 3-103TABLE 3-21 : COMPARISON OF ADCIRC SIMULATED RESULTS AND OBSERVED HIGHWATER MARKS -HURRICANE RITA (2005)....................................... 3-103TABLE 3-22: COMPARISON OF ADCIRC SIMULATED RESULTS AND OBSERVED HIGHWATER MARKS -HURRICANE GUSTAV (2008).................................. 3-104TABLE 3-23: COMPARISON OF ADCIRC SIMULATED RESULTS AND OBSERVED HIGHWATER MARKS -HURRICANE IKE (2008) ........................................ 3-104TABLE 3-24: ADCIRC SIMULATED ANTECEDENT HIGH WATER LEVEL.................. 3-104TABLE 3-25: ADCIRC STORM PARAMETER SENSITIVITY SIMULATIONS................ 3-105TABLE 3-26: FINAL PMSS STORM SET AND ADCIRC-SIMULATED RESULTS........... 3-106TABLE 3-27: ADCIRC SIMULATED RESULTS -WITH OFFSHORE AND POST-LANDFALLDECAY................................................................................... 3-106TABLE 3-28: ADCIRC SIMULATED RESULTS -ADJUSTED FOR ANTECEDENT WATER LEVELAND PROJECTED SUBSIDENCE.................................................... 3-107TABLE 3-29: RESULTS SUMMARY FOR CONTROLLING ALTERNATIVES ................ 3-165TABLE 3-30: WAVE RESULTS FOR H.1 ......................................................... 3-167Page 9 AA R EVA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportList of Tables(continued)PageTABLE 3-31: SUMMARY OF WATER LEVEL AND WAVE OVERTOPPING RESULTS ....3-168TABLE 3-32: HYDROSTATIC LOADING CALCULATION RESULTS.......................... 3-169TABLE 3-33: HYDRODYNAMIC LOADING CALCULATION RESULTS....................... 3-169TABLE 3-34: DEBRIS IMPACT CALCULATION RESULTS..................................... 3-170TABLE 3-35: ADCIRC+S WAN RESULTS FOR REPRESENTATIVE STORMS (FT, NAVD88-2004.65) ................................................................................. 3-171TABLE 3-36: SIMULATED ANTECEDENT WATER LEVELS ALONG COASTLINE AND IN THEMISSISSIPPI RIVER ................................................................... 3-172TABLE 3-37: 25-YEAR AID. 500-YEAR FLOOD FLOWS AND STAGES ................t.....3-173TABLE 3-38: MAXIMUM SIGNIFICANT WAVE CREST ELEVATIONS IN MISSISSIPPI RIVERNEAR WSES ............................................................................ 3-174TABLE 3-39: TIME-STAGE RELATIONSHIP -MISSISSIPPI RIVER LEVEE................ 3-174TABLE 3-40: TIME-STAGE RELATIONSHIP -INITIAL WATER LEVEL AT WSES ........ 3-175TABLE 3-41: SWAN OUTPUTS FOR REPRESENTATIVE STORMS AT WSES............. 3-176TABLE 4-1: FLOOD ELIdVATION COMPARISON ...........................................!.......4-2Page 10 AAR EVA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportList of FiguresPageFIGURE 2-1: SITE LOCATION MAP ................................................................ 2-5FIGURE 2-2: SITE TOPOGRAPHY AND LAYOUT ................................................ 2-6FIGURE 3-1: LIP HYETOGRAPH................................................................... 3-40FIGURE 3-2: FLO-2D MODELED SITE FEATURES............................................. 3-41FIGURE 3-3: WSES LIP LOCATIONS OF INTEREST ........................................... 3-42FIGURE 3-4: RELEVANT NPIS DETAILS ......................................................... 3-43FIGURE 3-5: PIPES CONNECTING THE FHB TO DCT BASINS ............................... 3-44FIGURE 3-6: FLOW CHART SHOWING MAJOR STEPS INVOLVED IN CALCULATING THESITE-SPECIFIC PMP FOR LIP ........!................................3-45FIGURE 3-7: DOMAIN USED TO IDENTIFY STORMS USED IN THE ANALYSIS............ 3-46FIGURE 3-8: LOCATIONS OF STORMS USED TO CALCULATE LIP VALUES FOR WSES3-47FIGURE 3-9: FHB AIR INTAKE AND EXHAUST OPENINGS ELEV. +1 FT, MSL............. 3-48FIGURE 3-10: DCT BASINS CONTRIBUTING AREAS LAYOUT................................ 3-49FIGURE 3-11: DCT BASINS STORAGE AREAS LAYOUT ...................................... 3-50FIGURE 3-12: MSIV CONTRIBUTING AREAS LAYOUT........................................ 3-51FIGURE 3-13: DOT BASINS AND FHB DEPTHS-I1 SUMP PUMP STARTINGAFTER 30 MINUTES .................................................................... 3-52FIGURE 3-14: DOT BASINS AND FHB FLOOD DEPTHS -1 SUMP PUMP STARTINGAFTER 0 MINUTES...................................................................... 3-53FIGURE 3-15: DCT BASINS AND FHB FLOOD DEPTHS -1 SUMP PUMP AND 1PORTABLE PUMP STARTING AFTER 30 MINUTES................................ 3-54FIGURE 3-16: DCT BASINS AND FHB FLOOD DEPTHS -1 SUMP PUMP AND IPORTABLE PUMP STARTING AFTER 0 MINUTES ................................. 3-55FIGURE 3-17: DCT BASINS AND FHB FLOOD DEPTHS -1 SUMP PUMP STARTINGAFTER 30 MINUTES AND I PORTABLE PUMP STARTING AFTER 1 HOUR .... 3-56FIGURE 3-18: DCT BASINS AND FHB FLOOD DEPTHS-I1 SUMP PUMP STARTINGAFTER 30 MINUTES AND 1 PORTABLE PUMP STARTING AFTER 3 HOURS .3-57FIGURE 3-19: DCT BASINS AND FHB FLOOD DEPTHS-I1 SUMP PUMP STARTINGAFTER 30 MINUTES, I PORTABLE PUMP STARTING AFTER 1 HOUR AND IPORTABLE PUMP STARTING AFTER 3 HOURS ................................... 3-58FIGURE 3-20: DCT BASINS AND FHB FLOOD DEPTHS -I1 SUMP PUMP STARTINGAFTER 0 MINUTES AND 1 PORTABLE PUMP STARTING ........................ 3-59FIGURE 3-21: MSIV EAST FLOOD DEPTHS...................................................... 3-60FIGURE 3-22: MSIV WEST FLOOD DEPTHS..................................................... 3-61FIGURE 3-23: HYDRAULIC CONTROL STRUCTURES IN THE LOWER MISSISSIPPIRIVER BASIN ............................................................................ 3-67FIGURE 3-24: PROJECT DESIGN FLOOD FOR THE LOWER MISSISSIPPI RIVER BASIN3-68FIGURE 3-25: HEC-RAS CROSS SECTIONS..................................................... 3-69FIGURE 3-26: LEVEES IN SOUTHERN LOUISIANA............................................. 3-70Page 11 AA R E VA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportFIGURE 3-27: REGIONAL LOCUS MAP OF HYDRAULIC STRUCTURES .................... 3-75FIGURE 3-28: USGS HUC WATERSHED BOUNDARIES ....................................... 3-76FIGURE 3-29: MAJOR DAMS IN LOWER MISSISSIPPI REGION WATERSHED UPSTREAMOF WSES ................................................................................. 3-77FIGURE 3-30: MAJOR DAMS IN ARKANSAS-WHITE-RED REGION WATERSHED ........ 3-78FIGURE 3-31: DISTANCE TO CLOSEST UPSTREAM DAM IN LOWER MISSISSIPPIREGION WATERSHED ................................................................. 3-79FIGURE 3-32: DISTANCE TO CLOSEST UPSTREAM DAM IN ARKANSAS-WHITE-REDREGION WATERSHED ................................................................. 3-80FIGURE 3-33: OVERVIEW OF PROCESS FOR COASTAL FLOODING CALCULATIONS 3-1 08FIGURE 3-34: DETERMINISTIC SLOSH SIMULATIONS -STORM TRACKS .............. 3-109FIGURE 3-35: DETERMINISTIC SLOSH SIMULATIONS -LANDFALL LOCATION MAP .. 3-110FIGURE 3-36: HIGHEST STORM TIDE WATER LEVELS ALONG THE U.S. GULF COASTFROM 1880 TO 2013 (SURGEDAT, 2014) .......................................... 3-111FIGURE 3-37: TRACKS OF MAJOR HURRICANES FROM 1851 -2010 .................... FIGURE 3-38: CHRONOLOGY OF THE LOOP CURRENT.................................... 3-113FIGURE 3-39: SCATTER PLOT -DP VERSUS RMAX ..............................................3-114FIGURE 3-40: SCATTER PLOT -VMA~XS VERSUS BEARING.................................. 3-115FIGURE 3-41: SCATTER PLOT -VMAXS VERSUS VF.............................................. 3-116FIGURE 3-42: SCATTER PLOT -VMAKS VERSUS RMAX........................................ 3-117 1FIGURE 3-43: SCATTER PLOT -VMAXS VERSUS Ap........................................ 3-118FIGURE 3-44: HURRICANE DATA CAPTURE ZONE FOR WSES ........................... 3-119FIGURE 3-45: FULL CAPTURE ZONE (GOM) VERSUS SUB-CAPTURE ZONE (LAT N26+)3-120FIGURE 3-46: MATRIX SCATTER PLOT- FULL CAPTURE ZONE ......................... 3-121FIGURE 3-47: MATRIX SCATTER PLOT -SUBSET DATA CAPTURE ZONE.............. 3-122FIGURE 3-48: POST-LANDFALL DECAY OF SELECTED HISTORICAL HURRICANES .. 3-123FIGURE 3-49: PRESSURE DEFICIT VERSUS RADIUS OF MAXIMUM WINDS FOR VMAXS>= 96 KNOTS ........................................................................... 3-124FIGURE 3-50: SCATTER PLOT -RMAx VERSUS Ap ........................................... 3-125FIGURE 3-51: HURRICANE INTENSITY VERSUS FORWARD SPEED...................... 3-126FIGURE 3-52: ADCIRC MESH ..................................................................... 3-127FIGURE 3-53: ADCIRC MESH RESOLUTION NEAR WSES.................................. 3-128FIGURE 3-54: ADCIRC MESH ELEVATIONS................................................... 3-129FIGURE 3-55: COMPARISON OF TIDE PHASE AND AMPLITUDE ALONG COASTLINE 3-130FIGURE 3-56: ADCIRC SIMULATED ANTECEDENT WATER LEVELS .......................3-131FIGURE 3-57: STORM TRACKS OF ADCIRC SENSITIVITY SIMULATIONS ............... 3-132FIGURE 3-58: ADCIRC PMSS SIMULATIONS -LANDFALL LOCATION MAP.............. 3-133FIGURE 3-59: MAXIMUM ELEVATIONS -STORM 202 WITH DECAY ...................... 3-134FIGURE 3-60: MAXIMUM ELEVATIONS NEAR WSES -STORM 202 WITH DECAY.....3-135FIGURE 3-61: WATER LEVEL TIME SERIES PLOTS -STORM 202 WITH DECAY......3-136FIGURE 3-62: LOCATION OF WSES RELATIVE TO THE GULF OF MEXICO .............. 3-143FIGURE 3-63: LOCUS MAP........................................................................ 3-144Page 12 AA R EVA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportFIGURE 3-64: LOCUS MAP WITH ELEVATION DATA (LAGIC, 2004)........................ 3-145FIGURE 3-65: SHADED RELIEF OF THE GULF OF MEXICO (USGS, 2009)................ 3-146FIGURE 3-66: TOPOGRAPHIC RELIEF OF WSES............................................. 3-177FIGURE 3-67: EFFECTIVE FETCH LENGTH (H.1)............................................. 3-178FIGURE 3-68: FLO-2D -H.1 MAXIMUM WATER SURFACE ELEVATION NEAR NPIS .... 3-179FIGURE 3-69: FLO-2D -H.1 MAXIMUM FLOW DEPTH NEAR NPIS......................... 3-180FIGURE 3-70: FLO-2D -H.1 MAXIMUM VELOCITY NEAR NPIS............................. 3-181FIGURE 3-71: FLO-2D- H.1 MAXIMUM VELOCITY VECTORS NEAR NPIS................ 3-182FIGURE 3-72: FLO-2D -H.2 MAXIMUM WATER SURFACE ELEVATION NEAR NPIS .... 3-183FIGURE 3-73: FLO-2D -H.2 MAXIMUM FLOW DEPTH NEAR NPIS ........................ 3-184FIGURE 3-74: FLO-2D -H.2 MAXIMUM VELOCITY NEAR NPIS............................. 3-185FIGURE 3-75: FLO-2D -H.2 MAXIMUM VELOCITY VECTORS NEAR NPIS................ 3-186FIGURE 3-76: REGIONAL AERIAL PHOTO LOCUS MAP..................................... 3-187FIGURE 3-77: MAXIMUM 16)-MINUTE WINDS IN THE GULF OF MEXICO FOR STORM 3023-188FIGURE 3-78: MAXIMUM 10-MINUTE WINDS IN THE GULF OF MEXICO FOR STORM402C ...................................................................................... 3-189FIGURE 3-79: MAXIMUM 10-MINUTE WINDS NEAR WSES FOR STORM 302............ 3-190FIGURE 3-80: MAXIMUM 10-MINUTE WINDS NEAR WSES FOR STORM 4020 ......... 3-191FIGURE 3-81: MAXIMUM UN..ADJUSTED WATER SURFACE ELEVATIONS FOR STQRM302 ....................................................................................... 3-192FIGURE 3-82: MAXIMUM UNADJUSTED WATER SURFACE ELEVATIONS FOR STORM402C ...................................................................................... 3-193FIGURE 3-83: MAXIMUM UNADJUSTED WATER SURFACE ELEVATIONS NEAR WSESFOR STORM 302 ....................................................................... 3-194FIGURE 3-84: MAXIMUM UNADJUSTED WATER SURFACE ELEVATIONS NEAR WSESFOR STORM 402C..................................................................... 3-195FIGURE 3-85: MISSISSIPPI RIVER WAVE CREST ELEVATION AND WAVE DIRECTIONMAP (STORM 402C)................................................................... 3-196FIGURE 3-86: FLO-2D -H.3 (402C) MAXIMUM WATER SURFACE ELEVATION NEARNPIS ...................................................................................... 3-197FIGURE 3-87: FLO-2D -H.3 (4020) MAXIMUM FLOW DEPTH NEAR NPIS................ 3-198FIGURE 3-88: FLO-2D -H.3 (4020) MAXIMUM VELOCITY NEAR NPIS .................... 3-199FIGURE 3-89: FLO-2D -H.3 (4020) MAXIMUM VELOCITY VECTORS NEAR NPIS......3-200FIGURE 3-90: TIME SERIES OF STANDING WAVE CREST ELEVATIONS FOR STORM(302) AT WSES ......................................................................... 3-201FIGURE 3-91: TIME SERIES OF STANDING WAVE CREST ELEVATIONS FOR STORM(402C) AT WSES ....................................................................... 3-202Page 13 AAR EVADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportAcronyms and AbbreviationsAcronym/Abbreviation Description10CFR50.54(f) Title 10 of the Code of Federal Regulations, Section 50.54(f)ANS American Nuclear SocietyANSI American National Standards InstituteASCE American Society of Civil EngineersASPRS American Society for Photogrammetry and Remote SensingAWL Antecedant Water LevelCCEF Controlling Combined Effect FloodGEM Coastal Engineering ManualCFR Code of Federal Regulationscfs cubic ft per secondCLB Current License BasisCO-OPS Center for Operational Oceanographic Products and ServicesDA Depth-AreaDAD Depth-Area-DurationDBFE Design Basis Flood ElevationDCT A Dry Cooling Tower AlphaDCT B Dry Cooling Tower BravoDEM Digital Elevation ModelDTM Digital Terrain ModelFEMA Federal Emergency Management AgencyFERC Federal Energy Regulatory CommissionFUB Fuel Handling BuildingFIS Flood Insurance StudyPage 14 AA R EVADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportAcronym/Abbreviation Descriptionfps ft per secondFSAR Final Safety Analysis ReportFSU Florida State UniversityMeteorological Criteria for Standard Project Hurricane and Probable MaximumFT Hurricane Windfields, Gulf and East Coast of the United States, Technical ReportFTGEV Generalized Extreme ValueGIS Geographic Information SystemsGoM Gulf of MexicoGSOD Global Surface Summary of Day DataHEC-RAS Hydrologic Engineering Center River Analysis SystemHI-A Hierarchical Hazard AssessmentHMR Hydrometeoro logical ReportHSDRRS Greater New Orleans Hurricane and Storm Damage Risk Reduction SystemHURDAT Hurricane DatabaseHWM High Water MarkISFSJ Independent Spent Fuel Storage InstallationISG Interim Staff Guidance (NRC)LiDARLight Detection and RangingLIP Local Intense PrecipitationLMSL Local Mean Sea LevelLOOP Loss of Offsite Powermb millibarsMCC Motor Control CenterMPI Maximum Potential IntensityMRGO Mississippi River Gulf OutletPage 15 AARE VADocument No.: 5 1-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportAcronymlAbbreviation DescriptionMSIV Main Steam Isolation Valve AreaMSL Mean Sea LevelNAD83 North American Datum of 1983NAVD88 North American Vertical Datum of 1988NESDIS National Environmental Satellite, Data, and Information ServiceNGDC National Geophysical Data CenterNGVD29 National Geodetic Vertical Datum of 1929NiD National Inventory of DamsNOAA National Oceanic and Atmospheric AdministrationNOS National Ocean ServiceNuclear Plant Island StructureNRC U.S. Nuclear Regulatory CommissionNTHMP National Tsunami Hazard Mitigation ProgramNTTF Near-Term Task ForceNWS National Weather ServiceODMI Operational Decision Making IssueORCS Old River Control StructurePDF Project Design FloodPMF Probable Maximum FloodPMH Probable Maximum HurricanePMP Probable Maximum PrecipitationPMSS Probable Maximum Storm SurgeRAB Reactor Auxiliary BuildingRAMMB Regional and Mesoscale Meteorology BranchRMSE Root Mean Square ErrorPage 16 AARE VADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportAcronym/Abbreviation DescriptionSLR Sea Level RiseSPF Standard Project FloodSSCs Structures, Systems and ComponentsSST Sea Surface TemperatureUH-S Ultimate HeatsinkUSACE U.S. Army Corps of EngineersUSBR U.S. Bureau of ReclamationUSGS U.S. Geological SurveytUTC coordinated universal timeVBS Vehicle Barrier SystemVma maximum wind speed it1 ktWCT A Wet Cooling Tower AlphaWCT B Wet Cooling Tower BravoWMO World Meteorological OrganizationWSES Waterford Steam Electric StationPage 17 AA R EVA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation Report

1.0 INTRODUCTION

Following the Fukushima Dai-ichi accident on March 11, 2011l, which resulted from an earthquake andsubsequent tsunami, the U.S. Nuclear Regulatory Commission (NRC) established the Near-Term Task Force(NTTF) to review the accident. The NTTF subsequently prepared a report with a comprehensive set ofrecommendations.In response to the NTTF recommendations, and pursuant to Title 10 of the Code of Federal Regulations, Section50.54(f), the NRC has requested information from all operating power licensees (NRC, 2012). The purpose of therequest is to gather information to re-evaluate seismic and flooding hazards at U.S. operating reactor sites.Waterford Steam Electric Station (WSES), located on the west bank of the Mississippi River in Killona,Louisiana, is one of the sites required to submit information. WSES is located near river mile 130, upstream ofand approximately 25 miles west of New Orleans, Louisiana.The NRC information request to flooding hazards requires licensees to re-evaluate their sites using updatedflooding hazard information and present-day regulatory guidance and methodologies and then compare the resultsagainst the site's current licensing basis (CLB)I for protection and mitigation from external flood events.1.1 PurposeThis report satisfies the "Hazard Reevaluation Report" Request for Information pursuant to 10 Code of FederalRegulations (CFR) 50.54(f) by the NRC dated November 12, 2012, NTTF Recommendation 2.1 FloodingEnclosure 2.The report describes the approach, methods an~t results from the re-evaluation of flood hazards at WSES.1.2 ScopeThis report addresses the eight flood-causing mechanisms and a combined effect flood, identified in Attachment 1to Enclosure 2 of the NRC information request (NRC, 2012). No additional flood causing mechanisms wereidentified for WSES.Each of the re-evaluated flood causing mechanisms and the potential effects on the WSES site are described inSections 3.0 and 4.0 of this report.1.3 MethodThis report follows the Hierarchical Hazard Assessment (HHA) approach, as described in NURIEG/CR-7046,"Design-Basis Flood Estimation for Site Characterization at Nuclear Power Plants in the United States ofAmerica" (NRC, 2011), NRC Interim Staff Guidance (IS G), as appropriate, and their supporting referencedocuments.A Hi-A consists of a series of stepwise, progressively more refined analyses to evaluate the hazard resulting fromphenomena at a given nuclear power plant site to structures, systems and components (SSCs) important to safetywith the most conservative plausible assumptions consistent with the available data. The HHA starts with themost conservative, simplifyTing assumptions that maximize the hazards from the maximum probable event. If theassessed hazards result in an adverse effect or exposure to any SSCs important to safety, a more site-specifichazard assessment is performed for the probable maximum event.The HHA approach was carried out for each flood-causing mechanism, with the controlling flood being the eventthat resulted in the most severe hazard to the SSCs important to safety at WSES. The steps involved to estimatethe design-basis flood typically included the following:1. Identify flood-causing phenomena or mechanisms by reviewing historical data and assessing thegeohydrological, geoseismic and structural failure phenomena in the vicinity of the site and region.Page 1-1 AA R EVA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation Report2. For each flood-causing phenomena, develop a conservative estimate of the flood from the correspondingprobable maximum event using conservative simplifying assumptions.3. If any SSCs important to safety are adversely affected by flood hazards, use site-specific data and/or morerefined analyses to provide more realistic conditions and flood analysis, while ensuring that these conditionsare consistent with those used by Federal agencies in similar design considerations.4. Repeat Step 2 until all SSCs important to safety are unaffected by the estimated flood, or if all feasible site-specific data and model refinement options have been used.Section 3.0 of this report provides additional HHA detail for each of the flood-causing mechanisms evaluated.Due to use of the HHA approach, the results (water elevation) for any given flood hazard mechanism may besignificantly higher than results that could be obtained using more refined approaches. Where initial, overlyconservative assumptions and inputs result in water elevations bounded by the CLB or water elevations that poseno credible hazard to the site, no subsequent refined analyses are required to develop flood elevations that aremore realistic or reflect a certain level of probability.1.4 AssumptionsAssumptions used to support the flood re-evaluation are described in Section 3.0 and its subsections, and dependon the mechanism being evaluated. Details relating to assumption justifications are discussed further inreferenced, supporting documentation. None of the assumptions require verification, i.e., need to be confirmedprior to use of the results.Discussions in this report which incl~.ide the terminology "design basis" indicates information develop~ed todetermine flooding hazard and requirements for flood protection, as indicated in Section 2.4 of the WSES F SAR(WSES, 2013).By definition, CLB (per 10OCFR54.3(a)) includes any NRC requirements, current and effective licenseecommitments, operation, and any design basis information for the site as documented in the most recent finalsafety analysis report.For the purposes of the WSES Flood Hazard Re-evaluation Report, the two terms, design basis and licensingbasis, can be considered to have the same meaning.1.5 Elevation ValuesElevations in the WSES Final Safety Analysis Report (FSAR) (WSES, 2013) refer to the Plant Datum, Mean SeaLevel (MSL). To convert elevations from the North American Vertical Datum of 1988 (NAVD88)-2004.65 toMSL (Plant Datum), 1.43 ft is added to the NAVD88-2004.65 elevation (see Appendix A). For the purpose ofthis report, elevations referenced as MSL refer to the Plant Datum. Note that for this location, MSL is notequivalent to the National Geodetic Vertical Datum of 1929 (NGVD29), or the Mean Sea Level Datum of 1929.This is due to ongoing settlement in the Mississippi Delta region.1.6 ReferencesNRC, 2011. NUREG/CR-7046, Design-Basis Flood Estimation for Site Characterization at Nuclear Power Plantsin the United States of America -NUREG/CR-7046, U.S. Nuclear Regulatory Commission, November 2011.(ADAMS Accession No. ML 1132 1A195)NRC, 2012. Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(0 RegardingRecommendations 2.1, 2.3 and 9.3 of the Near-Term Task Force Review of Insights from the Fukushima Dai-IchiAccident, U.S. Nuclear Regulatory Commission, March 2012. (ADAMS Accession No. ML12053A340)WSES, 2013. WSES Updated Final Safety Analysis Report, 2013, See AREVA Document No. 38-9243507-000.Page 1-2 AA REVA Document No.: 5 1-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation Report2.0 INFORMATION RELATED TO THE FLOOD HAZARD2.1 Detailed Site InformationThe WSES site is located on the west (right descending) bank of the Mississippi River near River Mile 130,approximately 25 miles upstream of New Orleans (See Figure 2-1). The site area consists of over 3000 acres withapproximately 7500 ft of river frontage. The WSES site grade ranges from approximately 14.5 ft MSL on thesouth side to 17.5 ft MSL on the north side (WSES, 2013, Section 2.4.1I). The river frontage of the WSES siteconsists of United States Army Corps of Effgineers (USACE) maintained levee with a top elevation ofapproximately 30 ft MSL.2.1.1 Site LayoutFigure 2-2, Site Topography and Layout, shows the WSES site layout and topography, including importantfeatures and locations related to flood hazards (AREVA, 2014).The following buildings are identified in Figure 2-2 using acronyms:* Fuel Handling Building (FHB)o Dry Cooling Tower Alpha (DCT A)* Dry Cooling Tower Bravo (DCT B)* Wet Cooling Tower Alpha (WCT A)SWet Cooling Tower Bravo (WCT B)* Reactor Auxiliary Building (RAB)* Nuclear Plant Island Structure (NPIS)* Main Steam Isolation Valve Area (MSIV East and MSIV West)2.2 Current Design Basis Flood ElevationThe current design basis and related flood elevation from natural sources is described in the WSES FSAR (WSES2013, Section 2.4) and in the Fukushima Flooding Walkdown Report Engineering Report for Entergy WaterfordSteam Electric Station Unit 3 NTTF Recommendation: 2.3 Flooding (Walkdown Report) (WSES, 2012) requiredas part of the response to the 10 CFR 50.54(f) letter.The design basis flooding event at WSES is a levee failure during a Probable Maximum Flood on the MississippiRiver (PMF) and a Probable Maximum Hurricane (PMH) at the mouth of the Mississippi River. This results in amaximum Design Basis Flood Elevation (DBFE) of 27.6 ft MSL (WSES, 2013, Section 2.4).Note that the information and elevations indicated in Section 2.2 (including subsections) are taken from theWSES FSAR (WSES, 2013) and the WSES Walkdown Report (WSES, 2012).Additionally, Probable Maximum Precipitation (PMP) induced ponding in the DCT areas is postulated to remainbelow a height of 1.6 ft, which is below any SSCs important to safety in those areas.2.2.1 Elevation of Safety Structures, Systems and ComponentsAll SSCs important to safety are flood protected because they are enclosed in a rectangular box-like reinforcedconcrete structure 380 ft. long, 267 ft. wide, and extending 64.5 ft. below grade known as the NPIS. The NPJSwall has a minimum protection elevation of 29.25 ft MSL. (WSES, 2012)There are a total of seven exterior, flood-protected access doors below 29.25 ft MSL which prevent flood watersfrom entering the NPIS. In the Reactor Auxiliary Building there are three doors located in the east exterior wall,Page 2-1 AA R EVA Document No.: 5 1-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation Reportand two located in the west exterior wall above 21 ft MSL. In the Component Cooling Water System area thereare two flood doors located in the west exterior wall above 21 ft MSL. In the Fuel Building area there is oneremovable flood-protected gate (modified to be welded shut) located by the spent fuel cask decontamination areaabove elevation 20 ft MSL. (WSES, 2012)The Dry Cooling Towers are located within the NPIS wall, but are open vertically to the atmosphere. As a result,there is potential for precipitation to infiltrate directly into the DCT areas. Inside DCT A and DCT B, there aresump pump motors and motor control centers (MCCs) for the ultimate heatsink (UHS) that are potentiallyvulnerable to flooding. The critical heights (above building slab) for SSCs inside DCT A and DCT B aresummarized below (WSES, 2001I). Flooding can exceed the height of the sump pump motors without directlyimpacting plant safety, but exceeding the heig ht of the UHS MCCs would result in loss of the UHS.Dry Cooling Tower Sump Pump Motor Motor Control Center for UHSAlpha (DCT A) l.5l ft 1.66Bravo (DCT B) 1.41 ft 1.652.3 Current Licensing Basis Flood Protection and Mitigation FeaturesThe NPIS common foundation mat and exterior wall system are designed to withstand all loadings and postulatedfloods as well as to minimize water intrusion. All exterior doors of the NPIS at plant grade or below the DBFE,which lead to areas that house and protect SSCs important to safety, are designed as flood protection doors towithstand the hydrostatic pressures due to the DBF$ and prevent water intrusion. Four valves form the floodbarrier for the FHB by providing a barrier between the Spent Fuel Pool Cask Decontamination Area (open to thetrain bay which is not flood protected) and the FHB sump. (WSES, 2012)Additionally, each DCT cell, and open area adjacent to the cells, is provided with area drains. The WCTs areprovided with overflows at their high water level elevations, which spill onto the open areas adjacent to them. Allarea drains in each Cooling Tower area are interconnected by a network of drainage piping which terminates at anarea drain sump for DCT A and at an area drain sump for DCT B. Each drain area sump is provided with a set ofmotor driven sump pumps. Each cooling tower area is also provided with a diesel powered sump pump. Duringthe design basis Probable Maximum Precipitation (PMP) event, it is assumed that one motor driven sump pump isengaged within 30 minutes of the onset of the event, and the diesel powered sump pump is engaged within 3hours of the onset of the event.The lowest elevation of the Fl-B (-35 ft MSL) is considered as rain water storage capability for the DCT areas.Water level equalization between the two areas occurs through four 4 inch pipes installed under two door sillslocated at each side of the FlAB. To maintain negative pressure in the FlAB, these pipes have two flappersinstalled, one per train. These flappers do not impede the flow of water into the FlAB. Two-thirds of the pipesneed to remain unblocked to maintain the necessary equalization rate.The FHB, RAB, and Reactor Building, have roof drains. There are a combined 21 drains of various sizes (4, 5,and 6 inch) credited for these three buildings. There are also 14 scuppers on the RAB roof. The FlAB and RABmust maintain two-thirds of their roof drainage capacity.2.3.1 CLB Flood Causing MechanismsThe potential impacts from several flood causing mechanisms are evaluated in the WSES FSAR (WSES, 2013,Section 2.4). These events include: PMP over the plant site; Levee failure during PMF; and PMH inducedProbable Maximum Storm Surge (PMSS) at the mouth of the Mississippi River; PMH- PMSS through BaratariaBay (with coincident wind waves); Probable Dam Failures, Seismically Induced; Probable Maximum Surge andSeiche Flooding; Probable Maximum Tsunami Flooding; Ice Effects; and Cooling Water Canals. Of these floodPage 2-2 AA R EVA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation Reportmechanisms, the controlling scenarios are the PMH induced PMSS at the mouth of the Mississippi Rivercoincident with a PMF and Levee Failure, and the PMP over the site with respect to ponding in the DCT areas.The DBFE for the WSES site is due to the Combined Effect scenario of a PMH induced PMSS at the mouth ofthe Mississippi River coincident with a PMF and levee failure at the site. The resulting flood level is a stillwaterelevation of 27.6 ft MSL. This scenario does not include appreciable wind-generated waves due to theconfiguration of the flood. The design basis flood level for the DCT areas due to rainfall runoff is 1.6 ft ofponding. (WSES, 2012)2.4 Licensing Basis Flood-Related and Flood Protection ChangesThere have been no significant changes to the licensing basis with respect to flooding or flood protection.2.5 Watershed and Local Area Changes2.5.1 Watershed ChangesThe Lower Mississippi River (including t~e Mississippi River segment which borders WSES) is navigated, and the USAGE New Orleans District is responsible for maintaining navigable conditions. As part ofthis responsibility, USAGE actively maintains revetments and flood control structures that have been constructedto minimize the risk of channel diversions, bank erosion, and instability. The absence of major morphologicalchanges in the region of the river adjacent to the site indicates that the river channel segment bordering WSES hasnot migrated in the past even though other parts of the river have exhibited a tendency to migrate. (See Section3.8)An extensive levee system has been conslructed in southeast Louisiana. The levee system and hydraulic c~ntrolstructures are owned and maintained by the USAGE and interconnect the Mississippi River floodplain with theAtchafalaya River floodplain for the purposes of maintaining channel stability, navigation and flood control. TheUSAGE structures along the Mississippi River and Atchafalaya River were designed based on the MississippiRiver and Tributaries Project Design Flood. In the past few years (subsequent to Hurricane Katrina in 2004), anew round of levee repairs and improvement projects have been completed, which are referred to as the GreaterNew Orleans Hurricane and Storm Damage Risk Reduction System. (See Section 3.4.1)2.5.2 Local Area ChangesDuring the initial phase of construction from 1975 to 1978 the plant settled approximately 0.75 ft resulting in anNPIS minimum protection elevation change from 30.0 ft MSL to 29.25 ft MSL (WSES, 2012). Since that initialsettlement, ongoing regional settlement has resulted in a cuffrent NPIS wall minimum height of 29.18 ft MSL(AREVA, 2014).2.6 Additional Site Details -Walkdown ResultsThe findings reported in the Walkdown Report (WSES, 2012) indicate that there is sufficient protection availableat the site to ensure the safe operation of the plant in the event of a design basis flood. The inspections includedall features credited for protection from the design basis flood, including all penetration or door seals below theminimum flood protection elevation of 29.25 ft MSL.During the walkdowns, conditions that did not meet the acceptance criteria were entered into the CorrectiveAction Program at WSES. The operability reviews of these conditions determined that the issue did not preventsafe plant operation or create a flooding risk for any safety-related equipment at the site. Based on the results ofthe visual inspections and the information provided in the current licensing basis at WSES, safe operation of theplant would be maintained in the event of a design basis external flooding event. (WSES, 2012)Page 2-3 AA R E VA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation Report2.7 ReferencesARE VA, 2014. Waterford Nuclear Generating Station -WSES: Aerial Mapping Validation Report, prepared byMcKim & Creed, July 2014. See AREVA Document No. 38-9226991-000.WSES, 2001. WSES Calculation EC-M99-010, Revision 0-2, August 2001, See AREVA Document No. 38-9243507-000.WSES, 2012. Flooding Walkdown Report -Entergy's Response to NRC Request for Information Pursuant to 10CFR 50.54(f) Regarding the Flooding Aspects of Recommendation 2.3 of the Near-Term Task Force Review ofInsights from the Fukushima Dai-Ichi Accident, Waterford Steam Electric Station, Unit 3 (Waterford 3), DocketNo. 50-382, License No. NPF-38, 2012. (ML12333A147)WSES, 2013. WSES Updated Final Safety Analysis Report, 2013, See AREVA Document No. 38-9243507-000.Page 2-4 AARE EVADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportFigure 2-1: Site Location MapAny illegible text or features in this figure are not pertinent to the technical purposes of this document.Page 2-5 AARE VADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportFigure 2-2: Site Topography and Layout10 50100 200 300 400I II I ' m I FeetAny illegible text or features are not pertinent to the technical purposes of this document. Site topography,orthoimagery, and plant structure delineation from AREVA, 2014.Page 2-6 AA R EVADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation Report3.0 FLOOD HAZARD RE-EVALUATIONThis section details the evaluation of the eight flood causing mechanisms and combined effects for WSES asdetailed in Attachment 1 to Enclosure 2 of the NRC information request. No additional flood causingmechanisms were identified for WSES.Page 3-1 AA R EVA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation Report3.1 Local Intense Precipitation3.1.1 Local Intense Precipitation -External to NPISThis section addresses the potential for flooding at WSES due to Local Intense Precipitation (LIP) outside of theNPIS wall. The potential for flooding due to the LIP inside the NPIS is addressed in Section 3.1.2. The LIP eventis a distinct flooding mechanism that consists of a short-duration, locally heavy rainfall centered upon the plantsite itself.This section summarizes the External LIP evaluation documented in AREVA Calculation No. 32-9226993-000(AREVA, 2014a).3.1.1.1 MethodThe HI-A approach described in NUREG/CR-7046 (NRC, 2011) was used for the evaluation of the LIP and theresultant water surface elevation at WSES. The HI-A approach for external LIP used the following steps:I. Develop LIP/PMP inputs.2. Develop the FLO-2D computer model with site Jfeatures.3. Perform flood simulations in FLO-2D to calculate maximum flood depths throughout the WSES site (notincluding ponding inside the NPIS/DCT areas).3.1.1.2 ResultsAll SSCs important to safety are located within the NPIJ; which is a "reinforced concrete box structure with solidexterior walls" (WSES, 2013) and is protected from external flooding to elevation 29.18 ft MSL (27.7 ft,NAVD88; AREVA, 2014b). Exterior doors that lead to areas containing safety-related equipment within theNPIS, that are located below the flood protected elevation, are watertight (WSES, 2013). The power block ofWSES is virtually enclosed by concrete barriers, referred to herein as the Vehicle Barrier System (VBS), and isconstructed from concrete blocks placed end to end to create a continuous barrier.The FLO-2D model for LIP flooding analysis at WSES uses 2014 topographic mapping results (AREVA, 2014b)to generate ground elevations and associated flood water surface elevations.3.1 .1 .2.1 PrecipitationNote that the CLB evaluation of PMP for WSES used rainfall from Hydrometeorological Report No. 33 (HMR-33) (NOAA, 1956): 11.67 inches over one hour and 30.7 inches over 6-hours. HMR-33 has since beensuperseded by Hydrometeorological Reports No. 51 (HMR-51I) (NOAA, 1978) and No. 52 (HMR-52) (NOAA,1982). HMR-5 1 and HMR-52 provide generic PMP guidance for areas in the United States east of the 105thmeridian. This LIP evaluation conservatively uses rainfall parameters from HMR-5 1 and HMR-52, in accordancewith NUREG/CR-7046 (NRC, 2011, Section 3.2). Note that since the results for the external LIP obtained usingHMR-51I and HMR-52 were acceptable, the external LIP analysis did not require using site-specific PMPinformation to refine the generic HMR-5 1 and HMR-52 inputs, in accordance with the HI-A approach.A front-loaded temporal distribution was used as per NUREG/CR-7046 (NRC, 2011I). The sub-divisions from thesecond hour to the sixth hour are based on recommendations in NUREG/CR-7046, Appendix B. The one-square-mile, one-hour duration PMP was estimated from I-MR-52 (NOAA, 1982) to be 19.4 inches. The one-hour PMPwas further subdivided into shorter duration increments based on the methodology of HMR-52. The sub-one hourdivision ratios are 0.32-, 0.50-, and 0.73 in the first 5-, 15-, and 30-minutes, respectively (Appendix B; NOAA,1982). The ten-square-mile, six-hour duration PMP was estimated from HMR-51 (NOAA, 1978) as 32 inches.The ten-square-mile, six-hour duration PMP hyetograph is shown in Figure 3-1. The 5-minute incremental rainfalldepth from the second hour to the sixth hour was calculated as 0.21 ft (i.e. 2.52 inches) and is the differencePage 3-2 AAR EVA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation Reportbetween the ten-square-mile, six-hour duration PMP and the one-square-mile, one-hour duration PMP spreadevenly in 5-minute increments over the five hour period (NRC, 2011).3.1.1.2.2 FLO-2D Model DevelopmentDue to anticipated unconfined flow characteristics outside of the NPIS, a two-dimensional hydrodynamiccomputer model, FLO-2D, was used for this calculation. FLO-2D is a physical process model that routes floodhydrographs and rainfall-runoff over unconfined flow surfaces or in channels using the dynamic waveapproximation to the momentum equation (AREVA, 201 4c). The watershed applicable for the LIP analysis wascomputed internally within FLO-2D based on the digital terrain model (DTM) limits input into FLO-2D(AREVA, 2014b).The FLO-2D model includes topography, site location, and building structures. Grid elements along the modelcomputational boundary were selected as outflow grid elements.3.t.1.2.3 FLO-2D Computer Model with Site FeaturesThe FLO-2D model developed for the LIP analysis was based on WSES site features including: topography, sitelocation, VBS layout, and structures. The selected grid element size for the project was 10 ft by 10 ft. Theelevation data used to develop the FLO-2D model consist of 2014 DTM data (AREVA, 2014b) for WSES. Flowobstructions due to buildings were also included in the model. The main input parameters for the WSES FLO-2Dmodel include:Elevation Data: Elevation grid for the project area was calculated based on the site topographic survey plan forWSES (AREVA, 2014b). The surveyed topographic map is in Louisiana South (1702) State Plane CoordinateSystem, North American Datum (NAD) (Conus) (horizontal) datum and elevations are in NAVD88 (GEdIID12A) (vertical) datum. The unit of the survey is U.S. ft. The elevation data imported into the FLO-2D model issupplemented by surveyed information.The methodology of the topographic survey was Light Detection And Ranging (LiDAR), with resulting dataprovided in AutoCADTM format (AREVA, 201 4b). The DTM used was extracted from the AutoCAD file.Additional elevation data was used based on the topographic site plan produced along with the DTM.Topographic data for WSES was developed based on a site-specific aerial survey using methodology consistentwith the need for first-order level of accuracy. The topographic survey performed in 2014 at WSES was requiredto meet the American Society for Photogrammetry and Remote Sensing (ASPRS) Class I Accuracy Standard for1" =100' planimetrics and 1-foot contour intervals, with +/- 1 ft horizontal accuracy, +/- 0.33 ft Root MeanSquare Error (RMSE) vertical accuracy for 1 foot contours and +/- 0.17 ft RMSE vertical accuracy for spotelevations and DTM points, at well-defined points. Additional designated critical structures and locations withrespect to site flooding impacts were identified and surveyed with a vertical accuracy of +/- 0.17 ft. Themethodology of the topographic survey was aerial LIDAR mapping of the site with sufficient control points forcalibration meeting the mapping standard, and conventional ground survey loops for the critical structures andlocations (AREVA, 2014b).FLO-2D grid element elevation data was interpolated based on imported DTM points from the topographic surveyof the site that were added to the working region. Interpolation methods available in FLO-2D include:* Using a user specified minimum number of closest DTM points within the vicinity of a grid element tocompute the grid elevation;* Using a user specified radius of interpolation which defines a circle around each grid element node toselect DTM points for use in computing the grid element elevation; and* Using an inverse distance weighting formula exponent to assign elevations to the grid element from theDTM points.Model grid elevations cannot be more accurate than the survey they are based upon. Therefore model gridelevations have a minimum level of uncertainty of +/- 0.17 ft. A minimum of two closest DTM points within thePage 3-3 AA R E VA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation Reportvicinity of a grid element was used in computing grid elevations. The density of spot elevations on the DTMprovided for adequate coverage for each grid element. Interpolated grid elevations at all critical points were spotchecked against the survey elevations and adjustments were made as needed. Model interpolation errors aretherefore believed to be very minimal.Uncertainty regarding onsite flood elevations is generally limited to the level of accuracy of the site survey. Thenature of the two dimensional flow model is such that the impact of potential inaccuracy in the elevation of anysingle grid element is generally mitigated by the surrounding grid elements. LIP results were computed asmaximum water surface depths, which was then compared to the known height of flood protection at criticalelements, thus reducing uncertainty related to potential issues with elevation datum normalization.Buildings: Buildings at WSES were incorporated into the FLO-2D model by manually adjusting grid elementelevations based on the site survey and the high resolution orthoimagery (AREVA, 2014b). Area ReductionFactors and Width Reduction Factors were not used. Grid elements that were completely within the aerial extentof a building were assigned elevations at least 5 ft higher than the surrounding topography. Uniform elevationswere assigned to grid elements representing a single building to ensure that runoff from rooftops are uniformlydistributed to the surrounding areas. For buildings with different rooftop elevations adjacent to each other (asestimated based on DTM data (ARII VA, 201 4b), the relative change in rooftop elevations were represented as a2-ft relative difference in building grid element elevations. This ensures that general flow directions of runofffrom rooftops are considered.Outflow Grid Elements: Grid elements along the computational boundary were selected as outflow grid elements,as shown in Figure 3-2.Levee Strucctures: The VBS at WSEO was modeled using the levee structure component in FLO-2D. lLeveestructures in FLO-2D confine flow 6n the floodplain surface by blocking one or more of the eight av~iilable flowdirections. When the flow depth exceeds the levee height, the discharge over the levee is computed using thebroad crested weir flow equation with a weir coefficient of 3.1 (FLO-2D, 2014). The top elevation of the VBSwas set at elevation four ft above the underlying grid elevation (WSES, 2012). With the exception of the vehicleopening on the Northeastern end of the site, the site is fully enclosed within the VBS.Infiltration and Surface Roughness: Rainfall was directly transformed into runoff within FLO-2D. No initialabstractions and/or infiltration were used.The land use categories were selected based on aerial photography assessment (AREVA, 2014b). The Manning'sroughness coefficient values for the grid elements generally range from 0.02 for concrete and asphalt surfaces to0.20 for areas with short trees.3.1.1.2.4 LIP Simulation ResultsThe results of the WSES FLO-2D LIP model are summarized in Table 3-1. Locations of interest are shown onFigure 3-3. The LIP maximum water surface elevations outside the NPIS range from 16.4 ft MSL (15.9 ftNAVD88) near the southeast side of the Independent Spent Fuel Storage Installation (ISFSI) pad to 20.5 ft MSL(19.1 ft NAVD88) between the West Side Access and Tool Room. The maximum flow depths range from 0.5 ftat the southeast side of the NPIS to 1.1 ft at the southeast side of the ISFSI. The maximum velocities range from0.2 ft per second (fps) at the southeast side of the ISFSI to 2.2 fps on the southwest side of the NPIS. Flood waterwithin the VBS generally flows away from the relatively higher grounds in the vicinity of the NPIS toward therelatively lower grounds at the southeast and southwest ends of the site and overtops the VBS to exit the site.The FLO-2D reference manual (FLO-2D, 2014) provides three keys to a successful project application. Theseinclude volume conservation, area of inundation, and maximum velocities and numerical surging. The resultsindicate a successful model application (AREVA, 2014a).Page 3-4 AA R EVA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation Report3.1.2 Local Intense Precipitation -Internal to NPISThis section addresses the flooding inside the NPIS (specifically the DCT areas and the MSIV areas) at WSESdue to rooftop runoff and direct precipitation from the LIP event. The LIP event results from the PMP eventcentered over the site area and the local watershed.This section summarizes the NPIS LIP evaluation documented in AREVA Calculation No. 32-9231496-000(AREVA, 2015ha).3.1.2.1 BackgroundThe following information is paraphrased from the WSES FSAR (WSES, 2013), unless otherwise noted. AllSSCs important to safety at WSES are located within the NPIS. The NPIS is a "reinforced concrete box structurewith solid exterior walls" according to the WSES FSAR and is protected from external flooding to approximately13 ft above general site grade. Exterior doors that lead to areas containing safety-related equipment within theNPIS that are located below the flood protected elevation are watertight. Relevant NPIS details are shown onFigure 3-4.As shown in Figure 3-4, tlhe NPIS consists of DCTs A and B, open areas adjacent to the D&1Ts, WCTs A and B,the FHB, the Reactor Building, and the RAB. DCTs A and B and the adjacent open areas are not covered byroofs and are open to the atmosphere allowing for falling precipitation and runoff from adjacent roofs toaccumulate. The MSIV areas, located in the wings of the RAB, are also susceptible to falling precipitation. TheFHB, Reactor Building, and RAB, with the exception of the MSJV areas, are roofed structures with varying roofelevations.For the purpose of this report, the term "DCT Basins" is defined as the areas in and around the DCTs that arehydraulically-connected at the mat foundation finished floor elevation of -34.75 ft MSL to the DCT sump pumps.These areas include the DCTs and the open areas adjacent to the DCTs (Figure 3-4). Equalization of pondingdepths within each DCT Basin occurs via backflow of the floor drainage system (WSES, 1992). It should benoted that four 4-inch-diameter pipes hydraulically connect the sub-basement of the FHB to DCT Basin A andanother four 4-inch-diameter pipes connect the sub-basement of the FHB to DCT Basin B (Figure 3-5; WSES,1986; WSES, 1991lc). The pipes have a flapper (i.e., check) valve system that allows water to flow into but notout of the FHB (WSES, 1986).There are six air intake/exhaust openings on the top of the north side of the FHB that are open to the atmosphereallowing for falling precipitation to accumulate in the sub-basement of the FHB, which has a finished floorelevation of -34.75 ft, MSL (WSES, 2013, Section 9.3.3.2.1.2).Roof drains, scupper drains, and floor drains convey runoff from the Reactor Building dome, RAB roof, andMSIV areas to pipes that discharge outside of the NPIS. The drains were assumed to be 100-percent openbecause the area of the grate covering the respective pipe openings is much larger than the pipe openings. Inaddition, WSES has and will create additional operational plans to ensure that these pipes are free from debris thatmay block flow through them (WSES 2014a, WSES 2015a, WSES 2015b). These drains and scuppers areassumed to discharge freely away from the NPIS because rooftop elevations are at least elevation 41 ft MSL orhigher, indicating that backwater effects at the drain/scupper outlet are unlikely given that typical site grade isbetween 14.5 and 17.5 ft MSL (WSES, 1997).3.1.2.2 MethodologyThis report determines the ponding depths within the Dry Cooling Tower (DCT) Basins and the Main SteamIsolation Valve (MSIV) areas (see Figure 3-4); locations that contain SSCs important to site safety.The methodology is based on the use of a conservation of mass (i.e., volumetric balance) approach in a simplerelation of inflow to, outflow from, and changes in storage within the NPIS areas as follows:Page 3-5 AA R E VA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportInflow = Outflow + Change in Storage (Equation 1)Where:Inflow =Runoff from contributory areas and/or direct inputs from rainfall, cubic ft;Outflow = Discharge from pumping and/or drains (connected to piping leading out of the NPIS), cubic fi;Change in Storage --Ponding within NPIS areas, cubic ft.This analysis also incorporates the following updates relative to the existing design basis analysis:* This analysis uses site-specific PMP values developed in a separate calculation (AREVA, 2015b). The6-hour PMP includes embedded 5-minute, 15-minute, 30-minute, and 60-minute duration PMP valueswhereas the existing design basis analysis evaluated only the 6-hour and 1-hour duration PMP. Thus, thisanalysis uses greater precipitation intensities than the existing design basis analysis.* The mass balance time step increment used for this analysis ranges from one minute to five minutes toallow for calculation of resultant flood depths based on PMP durations as short as five minutes. Theexisting design basis analysis uses a 30-minute to one-hour time step increment. Thus, this analysis usesshorter time step increments than the existing design basis analysis.* The variation of pipe flow with flood depth (e.g., hydraulic head) is accounted for in this analysis. Theexisting design basis analysis used a volumetric approach that does not appear to consider hydrauliclimitations due to pipe characteristics and available hydraulic head at each time step.o The capacities of the scuppers and roof drains on the Reactor Building dome, RAB Roof Al,RAB Roof A2, RAB Roof A3, RAB Roof Bl, RAB Roof B2 and RAB Cl were assumed to be100-percent open because the area of the grate covering the respective pipe openings is muchlarger than the pipe openings. In addition, WSES has and will create additional operational plansto ensure that these pipes are free from debris that may block flow through them (WSES 201 4a,WSES 2015a, WSES 2015b).This updated analysis has a modeling period of 7-hours (i.e., one hour longer than the LIP). Although there is noprecipitation during the last hour of the modeling period, the outflows from pumping are considered to continue.3.1.2.2.1 RainfallA site-specific meteorology study was performed in accordance with the HHA methodology to calculate the LIPat the 1-square mile area size for duration ofh5-, 15-, and 30-minutes and I- through 6-hours at WSES. This sitespecific evaluation is documented in a separate calculation (ARE VA, 2015b).3.1.2.2.2 DCT BasinsThe method of analysis for determining the ponding depths in the DCT Basins is described in general termsbelow:1. Calculate inflows:a. Calculate temporally distributed precipitation.b. Calculate areas that will directly contribute to ponding inside the NPIS and transform rainfall torunoff for these areas.c. Calculate potential overflows from surrounding building roofs by transforming rainfall to runoffand apportioning based on roof configurations and parapet storage.2. Calculate storage volumes:a. Calculate areas where ponding can occur (i.e. storage areas).b. Calculate reductions in storage volume due to equipment foundations, internal walls, etc.Page 3-6 AA R E VA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation Report3. Calculate outflows:a. Calculate the outflows from Reactor Building and RAB roof drains and scupper drains.b. Calculate sump pump discharges.c. Calculate rating curve for flow into the FHB.4. Calculate ponding depth in each DCT Basin using the mass balance approach and computed depth-to-volume relationship for both basins. Due to the differing contributing areas and storage areas betweenDCT Basin A and DCT Basin B, the two areas were modeled separately to account for the possibility ofdiffering ponding depths.3.1.2.2.3 MSIV AreasThe two MSIV areas of the RAB are not hydraulically connected to either DCT Basin but are potentiallysusceptible to flooding due to direct precipitation (i.e., the areas are open to the atmosphere allowing for fallingprecipitation to accumulate). The MSIV areas have a parapet wall height of 24.5 ft MSL (WSES, 2001ic), whichprevents overflow from the MSIV areas to the DCT Basins because the height of the parapet walls is sign~ificantlygreater than the LIP depth (Figure 3-4).The existing design basis calculation for ponding within the MSIV areas, Calculation ECMl3-0O1 (Entergy,2014), indicates that the MSIV areas are protected from overflowing rainwater from the surrounding RAB roofs(see "Noncontributing Roof Area" in Figure 3-4) by a 15 inch high parapet wall and that the RAB roof drains,located in the surrounding roofs of the RAB, are adequately sized to handle the PMP rainfall (Entergy, 2014).This report follows the same approach (i.e., mass balance computations) used in the existing design basis1calculation (Entergy, 2014), but it refines two design inputs to reevaluate the maximum ponding depths w~ithin theMSIV areas including:* Updated PMP values from site-specific meteorology study; and* Floor drains and scupper drains discharge during LIP.The method of analysis for calculating the ponding depths in the MSIV areas is described in general terms below:1. Calculate inflows:a. Use temporally distributed precipitation previously calculated.b. Calculate areas that will directly contribute to ponding inside the MSIV areas and transformrainfall to runoff for these areas.c. Calculate potential overflows from surrounding building roofs by transforming rainfall to runoffand apportioning based on roof configurations and parapet storage.2. Calculate areas where ponding can occur (i.e. storage areas).3. Calculate outflows:a. Calculate the outflows from Reactor Building and RAB roof drains and scupper drains.b. Calculate outflows from the MSIV area drains.4. Calculate ponding depth in each MSIV area using the mass balance approach.No infiltration losses were considered in the calculation for the ponding depths within the DCT Basins or theMSIV areas (i.e., the site and contributory areas are assumed to be 100-percent impervious).Page 3-7 AA R EVA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation Report3.1.2.3 Results3.1.2.3.1 Calculate InflowsCalculate RainfallThe LIP event is a distinct flooding mechanism that consists of locally heavy rainfall centered over the site areaand the immediate local watershed. Initial analyses indicated that using generalized PMP values from HMR-5 1and HMR-52 would exceed the current design basis for the DCT SSCs important to safety. Therefore, inaccordance with the HHA approach, a site-specific meteorology study was performed to refine the generalizedPMP estimates provided by HMR-5 1 and HMR-52. The site-specific PMP study incorporates numerousimprovements over the generalized HMR-51 1 HMR-52 guidance, including the usage of 40+ years of additionalprecipitation records and several technological advancements in the analyses of historic extreme storms. Section5.2 of American National Standards Institute!/American Nuclear Society (ANSI/ANS)-2.8-1992 (ANS, 1992)indicates that parameters of the PMP should be determined by a meteorological study using a storm basedapproach. This analysis followed the storm-based approach as followed in HMR-53 (NOAA, 1980) and HMR-5 1(NOAA, 1978). The World Meteorological Organization (WMO) Manual for PMP determination (WMO, 2009)recommends this same approa~ch. Figure 3-6 displays the major steps used in the calculation ofjthe 1- and 6-hour,I-square mile PMP.The initial step in the development of the site-specific PMP values was to identify a set of storms which representrainfall events that are PMP-type local storm events. This included all storms used in HMR-51I (NOAA, 1978)and HMR-52 (NOAA, 1982), all storms included in the USACE Storm Studies analyses (USACE, 1973), as wellas more recent storms. Emphasis was placed on storms which produced high intensity rainfall shortdurations (6 hours or less). Th~e storm search domain included a region from the Central Plainsf (south of 41 0Nlatitude) through the Gulf of Mexico, east/west to locations within +/- 1,000 ft of the site elevation (Figure 3-7).These general guidelines for the storm search domain and transposition limits are similar to those described inHMR-5 1, Section 2.4.2 (NOAA, 1978). The storms which are important for LIP development at the WSES siteare known from previous storm analyses and storm maximization completed in the region (e.g. NOAA, 1978,NOAA, 1982, AWA, 2008, AWA, 2012, AWA, 2014).The storm-based approach uses actual data from historic rainfall events which have occurred over the site and inregions transpositionable to the site. These rainfall data are maximized in-place following standard maximizationprocedures (NOAA, 1978), then transpositioned to WSES.This resulted in 22 events being evaluated for use in the site-specific PMP calculation (Figure 3-8 and Table 3-2).Eleven of the storms were not covered by the HMR or USACE analyses. For these newly identified extremerainfall events without published Depth-Area-Duration (DAD) analyses, hourly rainfall grids and DADs werecomputed using the SPAS computer program (Parzybok et al., 2014). There are two main steps in the SPASDAD analysis: 1) the creation of high-resolution hourly precipitation grids and 2) the computation of Depth-Area(DA) rainfall amounts for various durations. Because this process has been the standard for many years (all DADproduced by the NWS in FIMR 51 used this procedure) and holds merit, the SPAS DAD analysis process used inthis study attempts to mimic the NWS procedure as much as possible. By adopting this approach, consistencybetween the newly analyzed storms and the hundreds of storms already analyzed by the NWS is achieved.Storm maximization is the process of increasing rainfall associated with an observed extreme storm under thepotential condition that additional moisture could have been available to the storm for rainfall production. This isaccomplished by increasing the surface dew points (or sea surface temperatures, SSTs) to some climatologicalmaximum and calculating the enhanced rainfall amounts that could potentially have been produced if thoseenhanced amounts of moisture had been available when the storm occurred. In-place storm maximization isapplied to each storm. This study utilized the 6-, 12-, and 24-hour average 100-year recurrence interval dew pointclimatology and SST +2 sigma monthly average climatology. The development and results of these updated dewpoint and SST climatologies were extensively peer reviewed and accepted for use in PMP calculation by FederalPage 3-8 AA R EVA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportEnergy Regulatory Commission (FERC) and state dam safety regulators (AWA, 2008 and AWA, 2013,respectively).Once each storm is maximized in-place, it is then transpositioned from its original location to the site. Transfer ofa storm from where it occurred to a location that is meteorologically and topographically similar is known asstorm transpositioning. The transpositioning process accounts for differences in moisture and elevation betweenthe original location and WSES. For a given storm event to be considered transpositionable, there must be ofsimilar meteorological / climatological and topographical characteristics at its original location versus the newlocation. The general guidelines described in HMR-51 Section 2.4.2 are followed in this analysis.The process produces a total adjustment factor that is applied to the original rainfall data for each storm. Theresult represents the maximum rainfall each storm could have produced at WSES had all factors leading to therainfall been ideal. Table 3-2 provides each value used in this calculation, including the observed or derived 1-hour and 6-hour rainfall, the calculated total adjustment factor for each storm, and the resulting total adjusted 1-and 6-hour rainfall amounts.After the maximization and transposition factors were calculated for each storm, the results were applied to themaximum 1- and 6-pour value for each storm to calculate the maximized 1- and 6-ho~ir 1-mi2 value. The largestof these values results in the site-specific LIP for the site (Table 3-3). After adjustments were applied, the Thrall,TX September 1921 storm had the highest 1-hour and 6-hour rainfalls, with several other storms providingsupport with slightly smaller values. Note that the Smethport, Pennsylvania July 1942 storm, which produced the4- and 6-hour world record rainfall, was outside of the transposition limits to WSES shown in Figure 3-7,therefore this storm did not influence the LIP values at WSES. The refined transposition limits used in thiscalculation result in lower LIP values compared to HMR-52 for locations where the Smethport storm apparentlyinfluenced PMP valies. Smoothing of the PMP/LIP contours in HMR-51 and HMRI52 necessarily had toencompass the Smethport maximized in-place rainfall far beyond its explicit transposition limits. This over-envelopment effect extended well beyond the intended transposition limits of the Smethport storm (e.g. HMR-52Figure 26) because the PMP/LIP contours required smoothing and fitting over surrounding regions.For final applications, the 1-hour value is then required to be split into sub-hourly increments of 5-, 15-, 30-minutes. Therefore, the ratios derived in FIMR-52 (Figures 36-3 8 of I-MR-52; NOAA, 1982) were appliedspecific to the site location. The PMP depths results from the site-specific meteorology study are shown in Table3-3 and Table 3-4.This site-specific LIP study provided differences in LIP values from those presented in HMR-52. However, thiscalculation explicitly addressed elevation, used updated in-place maximization factors, and explicitly definedtransposition limits for each storm considered. These improved site-specific evaluations result in more accuratePMP values because specific characteristics of meteorology and topography of the site were considered, while inHMR-5 1 and HMR-52 they were not.Calculate Directly Contributing AreasOpen areas subject to direct precipitation were considered to be directly contributing areas. The rooftops ofsurrounding buildings were considered separately since only a portion of rainfall on the rooftops can overflowinto the areas of interest (i.e., the DCT Basins and the MSIV areas).DCT Basins Directly Contributing AreasThe "directly contributing areas" are open to the atmosphere and are subject to direct precipitation-inducedponding. DCT Basin A consists of the open areas on the west side of the NPIS including the wet cooling towerarea. Note that the enclosed walkway over DCT Basin A (labeled as "Full Contributing Roof with StorageBeneath" in Figure 3-4) is a flat roof with no parapet wall. Therefore, it was conservatively assumed that theprecipitation that fell on this roof would accumulate in the open area below the roof at elevation -34.75 ft MSLand would contribute to flooding at DCT Basin A. DCT Basin B consists of the open areas on the east side of theNPIS including the wet cooling tower area (see Figure 3-4 and Figure 3-10). It was assumed that 100-percent ofPage 3-9 AA R E VA Document No.: 51-9227040-000VWaterford Steam Electric Station Flooding Hazard Re-Evaluation Reportthe internal walls and 50-percent of the external walls of the DCTs contribute to ponding within the DCT Basinsbased on visual inspection.There are six air intake/exhaust structures on the north side of the FHB (Figure 3-9; WSES, 2011 a and WSES,2011 b). These horizontal openings were considered directly contributing areas since they are open to theatmosphere and allow precipitation to pool within the sub-basement of the FHB (WSES, 2013, Section9.3.3.2.1.2). The volume of water added to the system by these openings affects the available storage volumewithin the FHB that can be used by each DCT Basin.Areas directly contributing to ponding were calculated using AutoCAD and were based on the site survey data(AREVA, 2014b). Figure 3-10 outlines the directly contributing areas and the calculated values for DCT BasinA, DCT Basin B and the FHB air intake and exhaust openings are summarized in Table 3-5.MSIV Areas Directly Contributing AreasThe direct contributing area of MSIV East consists of the open area (i.e., covered by pervious overhead grating)on the eastt wing of the RA and the contributing area of MSIV West consists of the open area on the west wingof the RAB (see Figure 3-4). Ponding due to direct precipitation inflow is based on the MSIV areas that weretaken from the existing design basis calculation for ponding within MSIV areas, Calculation ECMI13-001(Entergy, 2014) because this information was not captured by the site survey (AREVA, 2014b). The area ofMSIV East was calculated at 4,051 square ft and the contributing are of MSIV West was calculated at 4,140square ft (Entergy, 2014).arbequp to performance of this evaluation, the MSJV storage areas revised to 4,088 square ft for eachCalculate Overflow Volumes from Surrounding~ Roof AreasThe surrounding roof areas with parapet walls adjacent to the open areas of the DCT Basins (Figure 3-4) willcontribute to ponding if the depth of pooling on the roof overtops the parapet walls. The volume of water thatwould overtop the parapet walls and flow into a particular area was calculated using a percentage based on theperimeter of roof that water can overtop and the length of roof that is shared with the area of interest. Theoverflow from the parapet walls was assumed to occur uniformly around the perimeter available for overflow. Itwas considered that the roof of the West Side Access Building, adjacent to WCT A, drains away from the NPISand does not contribute to ponding (see Attachment 8.3 of WSES, 2001b).DCT Basins Overflow Volumes from Surrounding Roof AreasThe following list includes the roofs and roof sections analyzed that had the potential to overflow and affect theDCT basins:* FH-JB Roof: Fuel Handling Building Roof that does not overflow to other areas.* RAB Roof Al: Roof Section Al of Reactor Auxiliary Building at El. 106.5 that drains to DCT A.* RAB Roof A2: Roof Section A2 of Reactor Auxiliary Building at El. 91.0 that drains to DCT A.* RAB Roof A3: Roof Section A3 of Reactor Auxiliary Building at El. 66.0 that drains to DCT A.* RAB Roof B 1 : Roof Section B 1 of Reactor Auxiliary Building at El. 80.5 that drains to DCT B.* RAB Roof B2: Roof Section B2 of Reactor Auxiliary Building at El. 41.0 that drains to DCT B.* RB Dome: Roof Section of Reactor Building that drains to DCT A and B.Page 3-10 AA R EVA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportFuel Handling Building RoofThe parapet walls on the roof of the FHB (Figure 3-4) are 33 inches high (WSES, 1991 b) and its roof drainsconvey flow beyond the NPIS (WSES, 2013). If the roof drains were completely blocked, the maximum depth ofponding would be equal to the 6-hour PMP of 27 inches (AREVA, 2015b). The 6-hour PMP would be containedwithin the parapet walls of the FHB roof and no overflow into the DCT Basins would occur. Water falling on theFHB was therefore not considered to contribute to ponding within the DCT Basins.Reactor Auxiliary Building RoofsThe RAB is comprised of roofs with varying elevations. The MSIV areas that are directly adjacent to the ReactorBuilding at elevation 46 ft MSL (Figure 3-4) have a tall parapet wall that is 24.5 ft high (WSES, 2001la).Flooding in the MSIV areas would not contribute to ponding within the DCT Basins because the 6-hour PMP is27 inches.Other RAB roofs adjacent to the DCT Basins were also considered. These roofs are labeled as "RAB RoofAlI",I'RAB Roof A2", "RAB Roof A3", "RAB RoofBl", and "RAB on Figure 3-4 and Figure 3-10. Theroofs labeled as RAB Roof Al, RAB Roof A2, and RAB Roof A3 contribute water to DCT Basin A. The roofslabeled as RAB Roof B 1 and RAB Roof B2 contribute water to DCT Basin B.The RAB roofs adjacent to the DCT Basins are drained by scuppers and roof drains (WSES, 1993). The RABRoof Al, RAB Roof A2, RAB Roof A3, and RAB Roof B1 are drained by 3-inch-diameter scuppers, and RABiRoof B2 is drained by a 4-inch-diameter roof drain (WSES, 199i). These scuppers and roof drains wereconsidered to be available and 100-percent clear because the area of the grate covering the respective pipeopenings is much larger than the pipe openings. In addition, WSES has operational plans to ensure that thesepipes and grates are free from debris that may block flow through them (WSES 2014a, WSES 2015a, WSES2015b). The parapet walls on these roofs are 1 foot (12 inches) high (WSES, 2001b). Overflow would occur ifthe depth of water exceeded the parapet walls.RAB Roof A1RAB Roof A1 is at a higher elevation than the surrounding roofs. If water on RAB Roof A1 reaches the height ofthe parapet wall, it would uniformly overflow the perimeter of the roof. The northern edge of RAB Roof Al isadjacent to RAB Roof A2. The water that would overflow this portion of RAB Roof A1 is expected to contributeto the ponding water on RAB Roof A2. The mass balance computations indicate that the 3-inch-diameter scuppercombined with the rooftop storage is sufficient to prevent overflow to RAB Roof A2 during the LIP.RAB Roof A2RAB Roof A2 is at a higher elevation than the roofs to the north, west and east. Uniform overflow over thesethree sides occurs if water on RAB Roof A2 reaches the height of the parapet wall. The northern edge of RABRoof A2 is adjacent to RAB Roof A3. The water that would overflow this portion of RAB Roof A2 is expectedto contribute to the ponding water on RAB Roof A3. The mass balance computations indicate that the 3-inch-diameter scupper combined with the rooftop storage is sufficient to prevent overflow to RAB Roof A3 during theLIP.RAB Roof A3RAB Roof A3 is at a higher elevation than the roofs to the north and west. The northern edge of RAB Roof A3 isadjacent to DCT Basin A. The water that would overflow this portion of RAB Roof A3 is expected to contributeto the ponding water in DCT Basin A. The mass balance computations indicate that the 3-inch-diameter scuppercombined with the rooftop storage is sufficient to prevent overflow to DCT Basin A during the LIP.Page 3-11 AA R EVA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportRAB Roof BlRAB Roof B1 is at a higher elevation than the surrounding roofs. A portion of the northern edge of RAB RoofB1 is adjacent to RAB Roof B2. The water that would overflow this portion of RAB Roof B1 is expected tocontribute to the ponding water on RAB Roof B2. The mass balance computations indicate that the 3-inch-diameter scupper combined with the rooftop storage is sufficient to prevent overflow to RAB Roof B2 during theLIP.RAB Roof B2RAB Roof B2 is at a higher elevation than the roof to the north, which is the DCT Basin. The water that wouldoverflow the northern portion of RAB Roof B2 is expected to contribute to the ponding water in DCT Basin B.The mass balance computations indicate that the 4-inch-diameter roof drain combined with the rooftop storage issufficient to prevent overflow to DCT Basin B.Reactor Building RoofThe Reactor Building is a domed structure surrounded by an approximately 4'-ft wide walkway with a 21l-inchhigh parapet wall (WSES, 2002a and Section 2.4.2.3.3 tof WSES, 2013). Precipitation falling over the area of thedome will pool along the perimeter at the walkway (WSES, 2002a). Once water reaches the height of the parapetwall, it spills over the parapet wall around the perimeter of the dome. A portion of the overflowing water willcontribute to DCT Basin A, DCT Basin B, and the RAB roof. The circumference of the dome was calculated at484 ft, 263 ft of which would contribute water to either DCT Basin A or DCT Basin B. Approximately 54-percent of the volume of water overflowing the parapet wall will contribute to ponding in the DCT Basins;therefore 27-percent would contribute to each DCT Bas in. The volume of water that flows over the southernportion of the RB dome, adjacent to the RAB, will contribute to the MSLV areas on Figure 3-4. The volume ofwater that overtops this section of the Reactor Building dome will not contribute to ponding in the DCT Basins.The Reactor Building roof walkway is drained by three 6-inch-diameter roof drains (WSES, 1993). These roofdrains were considered to be available and 100-percent clear.MSIV Areas Overflow Volumes from Surrounding Roof AreasReactor Auxiliary Building RoofsThe existing MSIV area calculation ECMl3-001 (Entergy, 2014), indicates that the MSIV areas are protectedfrom overflowing rainwater from the surrounding RAB roofs (see "Noncontributing Roof Area" in Figure 3-4) bya parapet wall and that the RAB roof drains, located in the surrounding roofs of the RAB, are adequately sized tohandle the CLB PMP rainfall (Entergy, 2014). However, due to the updated PMP values (AREVA, 2015Sb) thatare higher than the PMP values calculated in the existing MSIV area calculation, the overflow potential from theRAB roofs into the MSIV areas was reevaluated in this report. The roofs labeled as "RAB RoofCl", "RAB RoofC2", "RAB Roof C3", and "RAB Roof C4" shown in Figure 3-4 were included as roof areas contributing toflooding to the MSIV areas. Note that RAB Roof C5 does not contribute to flooding into the MSIV areas due toits lower elevation (46.0 ft MSL) than surrounding roof elevations.The surrounding roof areas with parapet walls adjacent to the open areas of the MSIV areas (Figure 3-12)contribute to ponding if the depth of pooling on the roof overtops the parapet walls. The parapet wall thatseparates the RAB Roof CI (former Noncontributing Roof Area" in Figure 3-4) from both the MSIV areas isapproximately 17 inches high according to a plant drawing (WSES, 1991 d). Note that the parapet wall storagesfor RAB Roofs C2, C3, and C4 were conservatively not accounted for in the overflow potential from RAB RoofCl to the MSIV areas calculations (see Figure 3-4).The RAB Roofs C2, C3, and C4 are located within the RAB Roof C extent and are at a higher elevation than theRAB Roof Cl (see Figure 3-4). Contributing inflows from RAB Roofs C2, C3, and C4 were directly translated toPage 3-12 AA R E VA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportRAB Roof Cl as no storage was credited for these parapet walls. The contributing areas of RAB Roofs Cl, C2,C3, and C4 are included in Table 3-6.RAB RoofCl1 is at a lower elevation than the surrounding roofs except for RAB Roof C5 located south of RABRoof Cl1. If water on the surrounding RAB Roofs Al1, A2, B 1, and B2 reach their respective height of the parapetwall, a portion of the overflow would discharge into RAB Roof Cl1 but the results show that runoff does notoverflow RAB Roofs Al, A2, B 1, and B2. Direct overflow from the reactor building walkway dome into theRAB RoofCl1 was accounted for in the mass balance computations. Approximately 100 ft (21-percent of domeperimeter) of the volume of water overflowing the parapet wall will discharge into RAB Roof Cl1. The massbalance computations indicate that the two six-inch-diameter roof drains combined with the roof top storage issufficient to prevent overflow from RAB Roof Cl. Note that other available roof drains and scuppers in the RABRoof Cl were not credited in the mass balance computations because they were not necessary. However, if theseunaccounted drains were to be credited, the maximum ponding depth at RAB Roof C1 would be lower.Reactor Building RoofThe circumference of the dome was calculated at 484 ft, 121 ft of which would directly contribute water to eitherMSIV East or MSIV West. Approximately }5-percent of the volume of water overflowing the parapet wall contribute to ponding in the MSIV areas, therefore 12.5-percent would contribute to each MSIV area.3.1.2.3.2 Calculate Storage VolumesDCT Basins Storage AreasStorage areas in which water would pond the separate DCTs within each DCT Basin, the open areas~adjacent to the DCTs in each DCT Basin, ant the sub-basement of the FHB. These areas are shown in Figurer3-11. The obstructed areas due to the WCTs, internal walls, equipment foundations, etc. were calculatedseparately and subtracted from the total storage areas.Areas were calculated using AutoCAD based on the site survey (AREVA, 20 14b) where available. If a storagearea was not captured by the site survey (i.e. it is located under/within a roof area), drawing G-580O, Sheet 3"Nuclear Plant Island Structure -Flood Wall Penetrations" (WSES, 1991 a) was used.Areas 1 through 9 compose DCT Basin B and Areas 10 through 16 compose DCT Basin A. A summary of thecalculated storage areas is presented in Table 3-7.MSIV Areas Storage AreasStorage areas within the MSIV areas include only the MSIV areas themselves. The storage area of MSIV East of4,051 square ft and MSIV West of 4,140 square ft were taken from the existing design calculation, ECM 13-001(Entergy, 2014).Equipment important to safety is located at least one foot off of the ground in the MSIV areas. Cables conduitsare potentially located within one foot of the floor and are designed to be temporarily submerged in water withoutbeing adversely impacted (Entergy, 2014). These conduits do not significantly affect storage volumes in theMSIV. Therefore, volume reductions are not present in the storage calculations.Subsequent to performance of this evaluation, the MSIV storage areas were revised to 4,088 square ft for eachMSIV area.Calculate RAB Roofs and Reactor Roof Storagze CapacityThe maximum storage volume that the Reactor Bulding dome parapet wall can accommodate without overtoppingis 4,063 cubic ft. The maximum storage volume the parapet walls can accommodate without overtopping RABPage 3-13 AA R EVA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportRoof A1, RAB Roof A2, RAB Roof A3, RAB Roof Bl, and RAB Roof B2 is respectively: 1,299, 387, 1,142,885, and 1,089 cubic ft.The maximum storage volume the parapet walls can accommodate without overtopping RAB Roof Cl isapproximately 25,160 square ft x 1.42 ft (17 inches) =35,727 cubic ft.Calculate Storage Volume ReductionsNo storage volume reductions were calculated for the MSIV areas. The following discussion covers the storagevolume reductions for the DCT Basins and FHB.The storage volumes for obstructions within each storage area were calculated and subtracted from the storagevolume calculated above on a depth-varying basis (e.g., storage volume reductions are different depending on theponding depth). Obstructions included, but were not limited to, conduit floor penetrations, columns, andequipment foundations. Fifty-percent of the volume occupied by the sump pumps was assumed to be availablefor ponding to account for the sump pumps and associated equipment (WSES, 2001ib). Fifty-percent of thevolume occupied by the shelving and storage locations was assumed to be available for ponding (WSES, 2001lb).The volume reduction of the air acczumulators was assumed to be equal to a rectangular shape of length andwidth of the accumulators and a height equal to that of the depth of ponding (WSES, 2001tb). The 10-inch-diameter and 12-inch-diameter pipes and the 20-inch-diameter CCW piping that run at elevation -33 ft, MSLwithin DCT Basins A and B and the FHB were assumed to be fully submerged. The previous calculationassumed these pipes were half submerged, bounded at 24-inches of ponding depth (WSES, 2001 b) and therefore,the previous values were conservatively multiplied by 2 in this updated calculation. A reduction in the availablestorage volume would directly lead to a greater depth of ponding.The adjusted storage volumes available at a particular ponding depth were calculated by subtracting thecumulative volume reductions from the unadjusted DCT volumes for DCT A and DCT B, respectively. A plot ofthe adjusted volumes versus the ponding depth was created and a linear regression equation was developed. Thelinear regression equation was used to calculate the overall ponding depth based on the calculated volume ofwater in each DCT Basin. The linear regression equations are as follows:Depth of = 0.00011412

  • Volume of Waterino~cr BasinA +t 0.10501908 (Equation 2)Depth of Podn~r ai = 0.00012632
  • Volume of Waterin OCt Basin B +r 0.08710623 (Equation 3)Depth of Pondingrnu = 0.00021901
  • Volume of WaternflFB + 0.00462122 (Equation 4)3.1.2.3.3 Calculate OufflowsCalculate RAE Roofs and Reactor Building Roof Drain CapacityThe three 6-inch-diameter drains on the Reactor Building dome walkway, the 3-inch-diameter scuppers on RABRoof Al1, RAB Roof A2, RAB Roof A3, and RAB Roof Bl, the 4-inch-diameter drain on RAB Roof B2, and thetwo six-inch-diameter drains on RAB Roof Cl1 were considered as outflows when calculating the potentialoverflow from the roofs. The roof drains and scuppers do not contribute to ponding in DCT Basins A or B, or theMSIV areas (e.g., runoff entering the roof drains and/or scuppers flows out of the NPIS system).The capacity of the drains and scuppers is dependent, in part, on the head of water above the drain (e.g., the depthof water pooling on the Reactor Building dome walkway). The capacities were assumed to be 100-percent openbecause the areas of the grate covering the pipe openings are much larger than the pipe openings. In addition,WSES has operational plans to ensure that these pipes and grates are free from debris that may block flow throughthem (WSES 2014a, WSES 2015a, WSES 2015b).Page 3-14 AkAR EVA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportThe capacities of the drains and scuppers were calculated based on the general weir equation (Equation 5) and theorifice flow equation (Equation 6). The, calculated flows using the two equations at each depth were comparedand the lesser of the flows at each depth was used as the limiting flow.The scuppers and roof drains will act as weirs until the water pooling along the Reactor Building dome walkwayand the RAB roof tops reaches a transitional depth into orifice flow. The capacity of the weirs was calculatedusing the equation below:Q2 = CLH3/2 (Equation 5)Where:Q= flow; cubic ft per second; cfs;C= weir coefficient; 3.0 (USACE, 2010);L= perimeter/circumference; ft;H= height of ponding water; ft.The capacity of the draiijs as orifices was calculated using the equation, below:Q = CJ~X(Equation 6)Where:Q= flow; cfs;C= orifice coefficient; 0.8 (USACE, 2010);A= area of orificg.; square ft;g= acceleration due to gravity; 32.2 ft per square second;h= height of ponding water relative to the orifice center-line; ft.It is possible for water to overflow the 21-inch parapet wall along' the Reactor Building dome root, and/or the 12-inch parapet walls along the RAB Roof Al, RAB Roof A2, RAB Roof A3, RAB Roof Bl, and RAB Roof B2,and/or the 17-inch parapet wall along the RAB Roof C1 boundary with the MSIV areas if the volume of waterentering the system (i.e. the precipitation) is greater than the volume of water that can be removed from thesystem by the roof drains and stored within the parapet surrounded area.The volume of water that can be stored along the perimeter of the dome was calculated by using the crosssectional area of the walkway as it changes with ponding depth and multiplying it by the circumference of thewalkway at its center. The curve of the dome was considered to be negligible and the cross sectional area wasessentially a trapezoid. The area of the trapezoid was calculated by adding the area of a rectangle (i.e., thewalkway) to the area of a triangle (i.e., approximating the shape of the dome).The volume of water that can be stored on the rooftops of RAB Roof Al, RAB Roof A2, RAB Roof A3, RABRoofBl1, RAB Roof B2, and RAB Roof Cl1 were calculated based on their respective roof top areas and the 12-inch high parapet walls (except for RAB Roof Cl1 that has 17-inch parapet walls).The rate at which precipitation was falling was compared to the rate at which volume was exiting via the drains.The calculated Reactor Building roof drain capacities in relation to ponding depths are presented in Table 3-8.The drain flow transitioned from weir flow to orifice flow at about 4 inches of depth and the maximum capacityof the three pipes with water depth just reaching the top of the parapet wall (assuming no obstmuction) is 5.0 cfs(i.e., 1,500.8 cubic ft per five minutes). The maximum storage volume the parapet wall can accommodate withoutovertopping is 4,063 cubic ft.The calculated 3-inch-diameter scuppers capacity in relation to ponding depths on RAB Roof Al, RABl Roof A2,RABl Roof A3, and RAB Roof B1 are presented in Table 3-9. The drain flow transitioned from weir flow toorifice flow at about 2 inches of depth and the maximum capacity of each scupper with water depth just reachingthe top of the parapet wall assuming no obstruction) is 0.32 cfs (i.e., 94.5 cubic ft per five minutes).Page 3-15 AA R EVA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportThe calculated 4-inch-diameter roof drain capacity in relation to ponding depths on RAB Roof B2 is presented inTable 3-10. The drain flow transitioned from weir flow to orifice flow at about 3 inches of depth and themaximum capacity of each scupper with water depth just reaching the top of the parapet wall (assuming noobstruction) is 0.56 cfs (i.e., 168.1 cubic ft per five minutes).The calculated combined capacity of the two six-inch-diameter roof drains in relation to ponding depths on RABRoof Cl is presented in Table 3-11. The drain flow transitioned from weir flow to orifice flow at about 4 inchesof depth and the maximum capacity of the two pipes with water depth just reaching the top of the parapet wall(assuming no obstruction) is 3.0 cfs (i.e., 900 cubic ft per five minutes).Calculation Pumping Discharge for DCT BasinsEach DCT Basin is hydraulically connected to one sump pump (Figure 3-4). These sump pumps were consideredas an outflow from the NPIS. It was assumed that a loss of offsite power (LOOP) would occur during an extremeprecipitation event (WSES, 2001ib). As a result of a LOOP, the sump pump in the FHB sub-basement wasassumed to be offline because it is not typically connected to the emergency diesel generators (WSES, 2001 b).Following the LOOP, it was assumed that the sump pumps would not begin to operate until 30 minutes after thestart of precipitation to allow for operator to restart the pumps (WSES, 2001 b).Each DCT sump pump is rated for 350 gallons per minute (gpm) (WSES, 2014b). The pump flow wasconservatively reduced to 300 gpm, while aligned with an inoperable circulating water system, which wasassumed to occur during a LOOP (WSES, 2002b). Therefore, a constant pumping rate of 300 gpm was used afterthe initial 30 minute setup time (WSES, 2001lb).A constant pumping rate of 300 gpm was used for each sump pump throughout the duration of the 6-hour durationLIP and in the hour following the end of precipitation. The pumping rate was converted to cubic ft per minute(cfm; 40.1 cfm) and then multiplied by 5 (200.5 cubic ft per 5 minutes) where necessary to match the timeinterval used in calculating the ponding depths. The following additional pump combinations / operationalassumptions (i.e., sensitivity analysis) were calculated:I. One installed sump pump for each DCT Basin starting 30 minutes after the onset of precipitation (300gpm) -Base Case;2. One sump pump for each DCT Basin starts immediately (i.e., at the first minute of precipitation).3. Two pumps in each DCT basin starting after 30 minutes: One sump pump and one portable pump in eachDCT Basin. The portable pumps are rated at the same capacity as the installed sump pumps. Theinstalled sump pumps and portable pumps started after the initial 30 minute setup time.4. Two pumps in each DCT basin starting at the onset of precipitation: One installed sump pump and oneportable pump starting at the beginning of precipitation.5. One installed sump pump starting after 30 minutes and one portable pump starting one hour after thebeginning of precipitation in each DCT basin.6. One installed sump pump starting after 30 minutes and one portable pump starting three hours after thebeginning of precipitation in each DCT basin.7. One installed sump pump starting after 30 minutes, one portable sump pump starting 1 hour after thebeginning of precipitation, and one portable pump starting 3 hours after the beginning of precipitation (atotal of three pumps), in each DCT basin.8. One installed sump pump at the beginning of precipitation and one portable pump starting 30 minutesafter the beginning of precipitation, in each DCT basin.Calculate Flow into the Fuel Handling Building for DCT BasinsThe FHB sub-basement is connected to each DCT Basin via four, 4-inch-diameter pipes, each with a flapper (i.e.,check) valve below Doors D204 and D206 (Figure 3-5) (WSES, 1986). The flapper valves allow water to flowPage 3-16 AkA R E VA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation Reportinto but not out of the FHB sub-basement (WSES, 1986). Thus, the FHB acts as a storage reservoir. The volumeof water from each DCT Basin that can be diverted into and stored within the FHB sub-basement was calculatedbased on the hydraulic capacity of the pipes and the head differential between the water in the DCT Basins andthe FHB. Flow through the pipes for a given head differential was calculated using CulvertMaster.CulvertMaster is a program designed to aid in analyzing and designing culverts using the US Federal HighwayAdministrations' Hydraulic Design of Highway Culverts (HDS-5) methodologies. CulvertMaster calculates theflow through the pipes based on the size, quantity, and roughness coefficient (AREVA, 2012). The four, 4-inch-diameter pipes below Doors D204 and D206 (Figure 3-5) are made of steel and were assigned a Manning'sroughness coefficient of 0.013 (USDOT, 2011) with an invert elevation of -34.75 ft, MSL (WSES, 1986) inCulvertMaster. The pipes were assigned a length of 3 ft (WSES, 1991 c).Note that the FUB sump pump was conservatively assumed to be offline as a result of LOOP because it is notconnected to the emergency diesel generators (WSES, 2001 b).Calculate MSIV Area Drains OutflowMSIV West has two 5-inch roof drains that drain outside the NPIS (Entergy, 2014). MSIV East has one 4-inchand one 5-inch scupper that drain outs i~te the NPIS (Entergy, 2014). The calculated capacity of the two ifive-inch-diameter floor drains in relation to ponding depths on MSIV West area is presented in Table 3-12. The dtrain flowtransitioned from weir flow to orifice flow at about 3 inches of depth and the maximum computed outflow of thetwo pipes combined relative to the computed maximum depth (assuming no obstruction) is 1.34 cfs (i.e., 80 cubicft per five minutes). The maximum storage computed in the MSIV West is approximately 2,560 cubic ft.The calculated four-inch-diameter and five-inch diameter scupper drains capacity in relation to ponding depths onMSIV East area is presented in Table i~-13. The drain flow transitioned from weir flow to orifice flow about 3inches of depth on both scupper drains. The maximum computed outflow of the two pipes combined relative tothe computed maximum depth (assuming no obstruction) is 1.17 cfs (i.e., 70 cubic ft per five minutes). Themaximum storage computed in the MSIV East is approximately 2,785 cubic ft.Calculate Ponding DepthsA spreadsheet-based mass (volumetric) balance of the inflows, outflows, and storage volumes was used tocalculate a maximum ponding depth in each DCT Basin and MSIV area as a result of the LIP. A variable 1-minute to 5-minute time step was used in the analysis. The spreadsheet-based mass balance is included in the LIPCalculation (AREVA, 2015a).DCT Basins Pondinn DepthsMaximum ponding depths within the DCT Basins due to the LIP for each pumping scenario are shown in Table3-14. This calculation has a modeling period of 7-hours (i.e., one hour longer than the LIP). Although there is noprecipitation during the last hour of the modeling period, the outflows from pumping are considered to continue.The total inflow from precipitation into DCT Basin A was calculated at 26,254 cubic ft. The total inflow fromprecipitation into DCT Basin B was calculated at 27,138 cubic ft. The total inflow from precipitation into theFHB was calculated at 1,026 cubic ft.The calculations for the inflows and outflows can be found in Appendix C of the LIP Calculation (ARE VA,2015Sa).The inflows, outflows, and capacity of the FHB pipes were combined with the storage volume reductionregression equations to produce resulting ponding depths. Figure 3-13 through Figure 3-20 are time series plotsshowing the depth of ponding in DCT Basin A, DCT Basin B, and the FHB.MSIV Areas Pondinn DeothsPage 3-17 AAXR E VA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportThe inflows and outflows were combined with the linear storage volume relation to produce resulting pondingdepths.The equations calculated for each MSIV area are as follows:Volume of WaterMstv East = 4,051 ft2
  • Depth of PondingMstv East (Equation 7)Volume of WaterMswv West --= 4,140 ft2
  • Depth of Ponding~stv Vwest (Equation 8)Resultant maximum flood depths of 0.69 ft and 0.62 ft within the MSIV East and West areas, respectively, werecalculated. Ponding depths within the MSJV areas due to the LIP are shown in Table 3-15. Figure 3-21 andFigure 3-22 are time series plots showing the depth of ponding MSIV East and West, respectively. Thecalculations for the inflows and outflows can be found in Appendix I of the LIP Calculation (AREVA, 2015Sa).The updated MSIV storage areas provided after performance of this evaluation do not result in significant changesto the results of the initial MSIV ponding levels reported above.3.1 .3 ConclusionsThe results of the LIP analysis at WSES indicate that the computed flood depths are well the NPIS floodprotection level of 12 to 15 ft above the general site grade in the vicinity of the NPIS and, therefore, no externalLIP flood impacts are anticipated at WSES.Maximum computed flood depths within the DCT Basins due to LIP ponding vary depending on the number andstart time of pumps available. Maximum flood depths in DCT Basin A range from 1.18 ft to 1.53 ft for theconditions analyzed. Maximum flood depths in DCT Basin B range from 1.27 ft to 1.63 ft for the conditionsanalyzed. Maximum flood d~pths in MSIV East and MSIV West are 0.69 ft and 0.62 ft, respebtively.3.1.4 ReferencesAREVA, 2012. AREVA Document No. 38-9192493 -000, "Computer Software Certification -BentleyCulvertMaster v.3.3", GZA GeoEnvironmental, Inc., October 12, 2012.AREVA, 2014a. AREVA Document No. 32-9226993-000, "Waterford Steam Electric Station Flooding HazardRe-evaluation -Local Intense Precipitation," GZA GeoEnvironmental, Inc., 2014.ARE VA, 2014b. Waterford Nuclear Generating Station -WSES: Aerial Mapping Validation Report, prepared byMcKim & Creed, July 2014. See AREVA Document No. 38-9226991-000.ARE VA, 2014c. AREVA Document No. 3 8-9225054-000, "Computer Software Certification -FLO-2D ProModel, Build No. 14.03.07", GZA GeoEnvironmental, Inc., June 1 6, 2014.AREVA, 2015a. AREVA Document No. 32-9231496-000, "Waterford Steam Electric Station Flooding HazardRe-Evaluation -Nuclear Power Island Structure Local Intense Precipitation," GZA GeoEnvironmental, Inc.,2015.AREVA, 2015b. AREVA Document No. 32-9233937-000, "Waterford Steam Electric Station Flooding HazardRe-Evaluation -Probable Maximum Precipitation," GZA GeoEnvironmental, Inc., 2015.AWA, 2008. Applied Weather Associates, Statewide Probable Maximum Precipitation (PMP) Study for the stateof Nebraska, Prepared for Nebraska Dam Safety, Lincoln, NE, 2008AWA, 2012. Applied Weather Associates, Site-Specific Probable Maximum Precipitation (PMP) Study for theTarrant Regional Water District-Benbrook and Floodway Basins, Ft Worth, TX, 2012.AWA, 2013. Applied Weather Associates, Statewide Probable Maximum Precipitation (PMP) Study for the Stateof Ohio, Ohio Dam Safety, Columbus, OH, 2013.Page 3-18 AA R IEVA, Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportAWA, 2014. Site-Specific Probable Maximum Precipitation Study for the Duck River Basin, Alabama, preparedfor Utilities Board of the City of Culiman, AL, 2014.Entergy, 2014. "MSIV Area Flooding Analysis," Calculation ECM13-001, Revision 0, Entergy, 2014, SeeAREVA Document No. 3 8-9243507-000.FLO-2D, 2014. FLO-2D Pro Reference Manual, FLO-2D Software, Inc., Nutrioso, Arizona (www.flo-2d.com).NOAA, 1956. Seasonal Variation of the Probable Maximum Precipitation east of the 105th Meridian for areasfrom 10 to 1000 square miles and durations of 6, 12, 24, and 48 hours. Hydrometeorological Report No. 33 by USDepartment of Commerce, 1956.NOAA, 1978. Probable Maximum Precipitation Estimates -United States East of the 105th Meridian,Hydrometeorological Report No.5 1 (HMR-5 1) by US Department of Commerce & USACE, National Oceanicand Atmospheric Administration, June 1978.NOAA, 1980. Seasonal Variation of'l 0-square-mile Probable Maximum Precipitation Estimates, United StatesEast of the 105th Meridian, Hydrometeorological Report No.53 (HMR-53) by US Department of Commerce andUS Nuclear Regulaitory Commission, National Oceanic and Atmospheric Administration, April 1980.NOAA, 1982. Application of Probable Maximum Precipitation Estimates -United States East of the 105thMeridian, NOAA Hydrometeorological Report No.52 (HMR-52) by US Department of Commerce & USACE,August 1982.NRC, 2011. NUREG/CR-7046: Design-Basis Flood Estimation for Site Characterization at Nuclear Power Plantsin the United States of America", U.S. Nuclear Regulatory Commission, Springfield, VA, National TechnicalInformation Servic@, 2011.Parzybok, et al., 2006. Parzybok T.W. and E.M. Tomlinson 2006: A New System for Analyzing Precipitationfrom Storms, Hydro Review, Vol. XXV, No. 3, 58-65, 2006.USACE, 1973. US Army Corps of engineers (USACE), US Army 193 6-1973, Storm Rainfall in the UnitedStates, Depth-Area-Duration Data, Office of Chief of Engineers, Washington, D.C.USACE, 2010. U.S. Army Corps of Engineers Hydrologic Engineering Center, River Analysis System HEC-RAS, Hydraulic Reference Manual, Version 4.1, January 2010.USDOT, 2011. U.S. Department of Transportation Federal Highway Administration "Introduction to HighwayHydraulics -Appendix B." http://www.fhwa.dot.gov/engineeringihydraulics/pubs/08OgO/appb.cfmn. Updated4/7/2011. Accessed 11/24/2014.WMO, 2009. World Meteorological Organization (WMO), Manual for Estimation of Probable MaximumPrecipitation, Operational Hydrology Report No 1045, WMO, Geneva, 2009.WSES, 1986. WSES Drawing LOU-861-HV-100, Revision 0, "Flapper Assembly Detail at FHB Doors D-204 &D-206 for Maintaining Neg. Press.," April 1986. See AREVA Document No. 38-9243507-000.WSES, 1991a. WSES Drawing G-580 ShJ/et 3, Revision 2, "Nuclear Plant Island Structure Flood WallPenetrations -Sh. 3 Plan," April 1991 See AREVA Document No. 3 8-9243507-000.WSES, 1991b. WSES Drawing LOU-1564 G-589, Revision 8, "Fuel Handling Building Floor at El. +46.00 &Roof- Masonry," July 1991 See AREVA Document No. 3 8-9243507-000.WSES, 1991c. WSES Drawing LOU-1564 G-593 Sheet 1, Revision 13, "Fuel Handling Building Exterior &Interior Walls Masonry Sh. 1," July 1991. See AREVA Document No. 38-9243507-000.WSES, 1991d. WSES Drawing LOU-1564 G-560 Sheet 1, Revision 9, "Reactor Auxiliary Building Roof Slab atEL. +69.00 Masonry Sh. 1," April 1991. See AREVA Document No. 38-9243507-000.Page 3-19 AkA R EVA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportWSES, 1992. WSES Drawing LOU-1564 G-874 Sheet 1, Revision 11l, "Fuel Handling Building Plan El. -34.75-Sh. 1 Plumbing & Drainage," September 1992. See AREVA Document No. 3 8-9243507-000.WSES, 1993. WSES Drawing LOU-1564 G-889, Revision 8, "Roof Plan Plumbing & Draining," August 1993.See AREVA Document No. 38-9243507-000.WSES, 1997. WSES Drawing LOU-1564 G-880 Sheet 2, Revision 22, "Riser Diagrams & Details -Plumbing &Drainage," October 31, 1997. See AREVA Document No. 38-9243507-000.WSES, 2001a. WSES FSAR Figure 2.4-8, Revision 11, "Roof Drainage," May 2001. See AREVA DocumentNo. 38-9243507-000.WSES, 200lb. WSES Calculation EC-M99-0l0, Revision 0-2, August 2001. See AREVA Document No. 38-9243507-000.WSES, 2001c. WSES Drawing G-2 10, Revision 20, "General Arrangement Cooling Towers Plan," April, 2001.See ARE VA Document No. 38-9243507-000.WSES, 2002a. WSES Drawing G-148, Revision 23, "General Arrangement Reactor Building Sections,"Septembbr 2002. See AREVA Document No. 38-9243507-000.WSES, 2002b. WSES Calculation EC-M97-029, Revision 0, "Dry Cooling Tower Area Drain Sump PumpMinimum Capacity," May 2002. See AREVA Document No. 38-9243507-000.WSES, 2011a. WSES Drawing G-580 Sheet 1, Revision 3, "Nuclear Plant Island Structure Flood WallPenetrations -Sh. 1 Plan," April 2011 See AREVA Document No. 38-9243507-000.WSES, WSES Drawing G-580 Sheet 2, Revision 3, "Nuclear Plait Island Structure Flood WallPenetrations -Sh. 2 Plan," April 2011. See AREVA Document No. 3 8-9243507-000.WSES, 2012. WSES Drawing G493 Sheet 10, Revision 0, "Vehicle Barrier Sections & Details" February 2012(Appendix HI). See AREVA Document No. 38-9243507-000.WSES, 2013. WSES Updated Final Safety Analysis Report, 2013. See AREVA Document No. 38-9243507-000.WSES, 2014a. WSES Procedure Number OP-901-521 (Attachment 4) -"Severe Weather and Flooding,"Revision 315, 2015. See AREVA Document No. 38-9243507-000.WSES, 2014b. WSES Specification Document LOU-1564.089A, Revision 6, "Sump Pumps and Accessories -Nonnuclear," February 2014. See AREVA Document No. 38-9243507-000.WSES, 2015a. WSES CR Number 2015-2 125 -"Potential Flooding in Dry Cooling Tower (DCT) Areas basedon Fukushima Flood Hazard Reevaluation (FHlE) -Local Intense Precipitation Calculation," Revision 0, April 14,2015. See AREVA Document No. 3 8-9243507-000.WSES, 2015b. W SES CR Number 2015-01282, April 28, 2015. See AREVA D ocument No. 38 -9243507-000.Page 3-20 AARE VADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportTable 3-1: LIP Model ResultsRepresentative Grid Element LIP Peak Water Surface Maximum MxmmFoLocation Grid Element Elevation (ft, Elevation -With VBS (ft, Flow Depth Vlct fsNumber NAVD88) NAVD88) (ft) Vlct fsNorthwest corner of 1,8 571. ..NPIS 1,8 571. ..Northeast side of1586.0807NPIS 17,8331586.0807Southeast side of.3,1157620510NPIS 3,1 571. ..Between Tool Roomand RW Solid Bldg on 2,2Southwest side of 247018.2 19.1 0.9 2.2NPISBetween West SideAccess and ToolRoom on West side of 22,524 18.5 19.0 0.5 1.7NIPSNorthwest side of 1,7 561. ..NPIS 1,7 561. ..Southeast side of 4,8 471. ..ISFSI 4,8 471. ..Page 3-21 AARE EVADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportTable 3-2: Storms Used to Calculate the Site-Specific LIP ValuesMainmum 1-hour Maximu 6-lmi2 Rainfall hour liMax 6-hour Using HMAR 52 Rainfall Using WVaterford WVaterford 1- W~aterford 6-Max IOmj2 Ratio or SPAS I-7lm 52 Ratio or Total Adjustment hour bud hour imi2 PrecipitationStorm Name State Lat Lon Year Month Day Rainfall Rainfall Data SPAS Data Factor PM? PM? SourceST.GEORGE ___f GA 30.521 -82.038 !1911 !8 28 __ 19.10 14.90 8-91 15.20 122, 10.87 18.54 jSA3-1ITH AL ...... ... .. _ -i o 9T -7.297 -9 E -____-___-_..... -TO..... ..... .. 6.... ....--.-.... --:......... ...... LE ...... ..... .... -6:- ...--i .. ..NEOHOFL LSTT -OKS t 368_5 -95.6010 1926 9 1 2 1 400 _ 1340 8 .01 13.67 145 .9 I 2 'PAS EOUNA -,. OAL 35.177 -86.067 19293 '. 12 29.600 10..39 _ 82.5 ,~- 10..239 13 1.251 1 29.9 SPAS 1320YBs.NEBE OW -TX 29.0303 -9682.2 1936' 6 0 52100; 14.09 8 .37 14.328 1.10 10052 171'5 GMS5-EGLSO TX 2O' -97.5009 1940 6, 29 2.7 11,!. 00 6 .,0 .778 11.22 12,7 I 8495 14417 G{LL,.EWTE OKX 362.507 -96..91019401 9 27 24.00 1 8.92 42.9 18.42 1. .1 i 3.90 T .7 JSPAS 1429TRETO ............. .941 0 1 35.00 .7.7-2_I-3 I 13.1 106 -5 MOUD .S~ q O.....87.9606 0? 3- 16 17-i.00 t 16.-1 --8 .. ..T .. 8.2. 1...2a- ... 1.....9 .11 -- 22 56 --- _ 132S 6IVE LAK TX.. .. .....32670i~ 9Lb .59,6- 1943--- 69 5..... 16--- .50V -14.20-i- -- 849.... J .... 1448... ... ......... ..... 119....0.1 17.... 4 i? ...._sW33 ....Page 3-22 AAR EVADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportTable 3-3: Point (1-mi2) Local Intense Precipitation Depths at WSESWaterfordPMP Depth (in) at 1-hour 1-squareTime (mai) ,mile ,60 15.830 11.515 7.95 5.0WaterfordPMP Depth (in) at 6-hour 1-squaremile27.0Page 3-23 AA R EVADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportTable 3-4: Site-Specific PMP Rainfall DistributionTime Step .incremental PMP' Cumulative PMPValues .* Depths , ...Depths,:(hours), * (inches) .... , ,0.000 071.0000 0.000.... 1.0000 1.000, 0.033 ' 1.0000 2.000:0.067 ' 1.0000 4.000"0.083 " 1.0000 5.000* '0.100 .... 0,2900 5.2900.&17' 0.2900 5.580'0.133' 0.2900 5.870*=0.150., 0.2900 6.1600.2900 6.4500.1.. 83: 0.2900 6.740Si0.200 0.2900 7.030,' 0.217i '"' 0.2900 7.3207.6104'"'0.250 ' 0.2900 7.900S 0.2400 8.1400230.2400 8.3800.300 0.2400 8.6200.317 0.2400 8.8600.333 ..... 0.2400 9.1000.350 ' 0.2400 9.340**0.367 ... 0.2400 9.5800.2400 9.8200.2400 10.0600.417 :, 0.2400 10.3006.1433 .... 0.2400 10.5400.450 ..., 0.2400 10.7800.467 ... 0.2400 11.0200.483 0.2400 11.2600.500 , 0.2400 11.5000.517 0.1433 11.643*0.533' 0.1433 11.7870.550 .... 0.1433 11.9300.567 '0.1433 12.073S0.583 0.1433 12.2170.600 0.1433 12.3600.1433 12.5030,633 :, 0.1433 12.6470.650 0.1433 12.790Page 3-24 AAR EVADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportTime , Inii~cremental PMP ! Cumulati~ve PMP'; i0.I 0.1433 12.933, '01;683T ;!,i 0.1433 13,077;!; 13.2200.717 0l ii; .1433 13.363.1433 13.507.700.1433 13.6506.767!O ;! 0.1433 13.793i": ,! , 0.1433 13 .9370 0. 1433 14.080,, 0... .1433 14.2230.8i:;!;i:6i3;'}ii!ii: 0.1433 14.367:?:!!0:850,.: : 0.1433 14.510-:!: ; 0.1433 14.7970.1433 14.9400.1~0.1433 15.08309.33,;i 0.1433 15.2270 0!'; .1433 15.370-:: 0.1433 15.513Q )9183 ; 0.1433 15.65771i!'.000-. 0 !'i: O. 1433 15.8001.083 0.1867 15.9871.167 0.1867 16.1731.250 0.1867 16.3601.333 0.1867 16.5471.417 0.1867 16.7331.500 0.1867 16.9201.583 0.1867 17.1071.667 0.1867 17.2931.750 0.1867 17.4801.833 0.1867 17.6671.917 0.1867 17.8532.000 0.1867 18.0402.083 0.1867 18.2272.167 0.1867 18.4132.250 0.1867 18.6002.333 0.1867 18.7872.417 0.1867 18.9732.500 0.1867 19.1602.583 0.1867 19.3472.667 0.1867 19.5332.750 0.1867 19.720Page 3-25 AAR EVADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportTieStp Incremental PMP :Cumulative PMP;Values 1 Depths 2 ._Depths,(hours) (inches). (inches)2.833 0,1867 19.9072.917 0.1867 20.0933.000 0.1867 20.2803.083 0.1867 20.4673.167 0.1867 20.6533.250 0.1867 20.8403.333 0.1867 21.0273.417 0.1867 21.2133.500 0.1867 21.4003.583 0.1867 21.5873.667 0.1867 21.7733J750 0.1867 21.9603.833 0.1867 22.1473.917 0.1867 22.3334.000 0.1867 22.5204.083 0.1867 22.70741167 0.1867 22.8934.250 0.1867 23.0804.333 0.1867 23.2674.417 0.1867 23.4534.500 0.1867 23.6404.583 0.1867 23.8274.667 0.1867 24.0134.750 0.1867 24.2004.833 0.1867 24.3874.917 0.1867 24.5735.000 0.1867 24.7605.083 0.1867 24.9475.167 0.1867 25.1335.250 0.1867 25.3205.333 0.1867 25.5075.417 0.1867 25.6935.500 0.1867 25.8805.583 0.1867 26.0675.667 0.1867 26.2535.750 0.1867 26.4405.833 0.1867 26.6275.917 0.1867 26.8136.000 0.1867 27.0006.083 0.0000 27.0006.167 0.0000 27.0006.2500.000027.000Page 3-26 AARE EVADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation Reportr*' Va ues~ -: ,,.Depths2 ____..... (hours) (inhes (inches). ... ... .....6.333 0.0000 27.0006.417 0.0000 27.0006.500 0.0000 27.0006.583 0.0000 27.0006.667 0.0000 27.0006.750 0.0000 27.0006.833 0.0000 27.0006.917 0.0000 27.0007.000 0.0000 27.000Notes:]1. Time steps are in 1 minute increments for durationsless than 1 hour. For durations greater than 1 hour, thetime step is 5 minutes.2. PMP depths are from WSES Calculation 32-9233937-000 (AREVA, 2015).Page 3-27 AAR EVADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportTable 3-5: OCT Basins Summary of Contributing AreasContributin........g...................ea ... , :.;: Areas from EC-M99-01 0 Percent DifferenceDCT Basin A 11,197Exterior walls 312DCT Basin ATotal 11,041 11,122 1%DCT Basin B 11,720Exterior walls 573OCT Basin B Total 11,434 11,359 -1%Reactor Building Dome 18,627 18,627 0%RAB Roof B1 885 882 0%RAB Roof B2 1,089 1,100 1%RAB Roof Al 1,299 1,248 -4%RAB R~oof A2 387 360 -7%RAB Roof A3 1,142 1,170 2%1 782 783 784 745 746 74FHB AirlExhaust 1, 2 456 273 -40%Notes:1. Areas are considered directly contributing to ponding.2. FHB Air/Exhaust areas based of scaled drawing only (WSES, 201 Ia) since they were notcaptured by the site survey (AREVA, 2014). Areas includes 50-percent of adjacent exteriorwalls.3. Areas were calculated using AutoCAD.4. Areas were drawn in AutoCAD based on the site survey, unless otherwise noted.Page 3-28 AARE 'VADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportTable 3-6: MSIV Areas Summary of Contributing AreasAreasSquare FtMSIV East1 4,051MSIV West1 4,140Reactor Building Dome 2 18,527RAB Roof C1 3 25,160RAB Roof C2 3 195RAB Roof C3 3 445RAB Roof C4 3475Notes:1. areas taken from Calculation ECM13-001 (Entergy, 2014). I2. Reactor Building Dome area calculated as described in the DCT Basin and FHB Flooding Calculations.(WSES, 2013)3. Areas were calculated using AutoCAD and were based on the site survey data (AREVA, 2014).Page 3-29 AAR EVADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportTable 3-7: DCT Basins Storage Areas SummaryStorage Area, Area from WSES, 2001b Percent Difference1 409 411 0%2 527 546 -3%3 431 434 -1%4 423 518 -18%5 427 434 -2%6 517 532 -3%7 4,181 4,274 -2%8 360 353 2%9 764 765 0%DCT B 8,041 8,267 -3%10 392 397 -1%11 563 560 0%12 440 434 1%13 417 518 -19%14 432 434 0%15 522 518 1%16 6,071 5,95k 2%DCT A 8,838 8,813 0%FHB 5,867 6,595 -11%Notes:1. Areas 1-6, 8 and 11-15 are based off of a combination of the site survey (AREVA,2014) data and the scaled drawing (WSES, 1991a). Remaining areas, including theFHB, are based off of the scaled drawing (WSES, 1991a) since they are not capturedby the site survey.2. Area 16 in this calculation is a combination of Areas 16, 17, and 18 fromCalculation EC-M99-010 (WSES, 2001b).3. Difference in FHB areas is due to accounting for some interior walls thatCalculation EC-M99-010 (WSES, 2001b) takes into consideration in a later part of thecalculation.Page 3-30 AARE EVADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportTable 3-8: Reactor Building Roof Drain Capacity (Three 6-Inch Roof Drains)... .. : ...... , Comparison and Resulting Flow , .....Depth Weir Flow Orifice Flow Resulting Value'1 Resulting Value'1(cubic ft per 5(ft) (cfs) (cfs) (cfs) minutes)0.00 0.00 0.00 0.00 0.00.04 0.12 0.77 0.12 36.10.08 0.34 1.09 0.34 102.00.13 0.62 1.34 0.62 187.40.17 0.96 1.54 0.96 288.60.21 1.34 1.73 1.34 403.30.25 1.77 1.89 1.77 530.10.29 2.23 2.04 2.04 612.70.33 2.72 2.18 2.18 655.00.38 3.25 2.32 2.32 694.70.42 3.80 2.44 2.44 732.30.46 4.39 2.56 2.56 768.10.50 5.00 2.67 2.67 802.20.54 5.64 2.78 2.78 835.00.58 6.30 2.89 2.89 866.50.63 6.99 2.99 2.99 896.90.67 7.70 3.09 3.09 926.30.71 8.43__ 3.18_____ 3.18 954.80.75____ 9.18_____ 3.28_____ 3.28 982.50.79 9.96__ 3.36______ 3.36 1009.4__.83 _1__.7_ 3.45 3.45 1035.70.81.73.54 3.54 1061.20.92 12.41 3.6 3.62 1086.20.96 13.26 3.7 3.70 1110.6101413.83.78 1134.51.04____ 15.03 3.86_ 3.86 1157.91.08 __15.__4 3.94_____ 3.94 1180.81.13 16.87 4.01 4.01 1203.3.71784.84.08 1225.41.21 18.78 4.16_____ 4.16 1247.11.25 19.76 4.23___ 4.23 1268.41.29 20.75 4.04.30 1289.41.33 21.77 4.74.37 1310.01.38 22.79 4.43______ 4.43 1330.31.42 23.84____ 4.50______ 4.50 1350.3Page 3-31 AARE VADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation Report______,_ _________Comparison and Resulting FIow* _________________; ,Depth Weir Flow Orifice Flow Resulting Value 1 Resulting Value 1(ft) (cfs) (cfs) (cfs) (cubic ft per 5___________ _____________minutes)1.46____ __ 4.90___.5_ 4.57 1370.01.50 25.97 4.63 4.63 1389.51.54 27.06__ 4.70_____ 4.70 1408.61.58 28.17 4.76 4.76 1427.6__ .63___ ___.______._ 4.82 1446.2__ .67___ 30.42 4.88 4.88 1464.6.73154.44.94 1482.81.75____ 32.73____ 5.00_____ 5.00 1500.8Note:1. "Resulting Value" is the lesser or the weir flow and the orifice flow.Page 3-32 AARE EVADocument No.: 5 1-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportTable 3-9: One 3-Inch-Diameter Scupper Capacity_______ .............. Com aison aind R ulit gFOw ______Depth Weir Flow Orifice Flow Resulting Value 1 Resulting Value 1(ft) (cfs) (cfs) (cfs) minubitpes)50.00 0.00 0.00 0.00 0.00.04 0.02 0.06 0.02 6.00.08 0.06 0.09 0.06 17.00.13 0.10 0.11 0.10 31.20.17 0.16 0.13 0.13 38.60.21 0.22 0.14 0.14 43.20.25 0.29 0.16 0.16 471.30.29 0.37 0.17 0.17 51.10.33 0.45 0.18 0.18 54.60.38 0.54 0.19 0.19 57.90.42 0.63 0.20 0.20 61.00.46 0.73 0.21 0.21 64.00.50 0.83 0.22 0.22 6 .90.54 0.94 0.23 0.23 69.60.58 1.05 0.24 0.24 72.20.63 1.16 0.25 0.25 74.70.67 1.28 0.26 0.26 77.20.71 1.40 0.27 0.27 79.60.75 1.53 0.27 0.27 81.90.79 1.66 0.28 0.28 84.10.83 1.79 0.29 0.29 86.30.88 1.93 0.29 0.29 88.40.92 2.07 0.30 0.30 90.50.96 2.21 0.31 0.31 92.61.00 2.36 0.32 0.32 94.51. 'Resulting Value" is the lesser or the weir flow and the orifice flow.Page 3-33 AAR EVADocument No.: 51-9227040-000Waterford Steam Electric Station Fiooding Hazard Re-Evaluation ReportTable 3-10: One 4-Inch-Diameter Roof Drain Capacity_______ ' ,, ... " ; iCompar~ison and Resulting Flow .. ..... .......:Depth Weir Flow Orifice Flow Resulting Value 1 Resulting Value 1(cubic ft per 5(ft) (cfs) (cfs) (cfs) m in utes)0.00 0.00 0.00 0.00 0.00.04 0.03 0.11 0.03 8.00.08 0.08 0.16 0.08 22.70.13 0.14 0.20 0.14 41.70.17 0.21 0.23 0.21 64.10.21 0.30 0.26 0.26 76.70.25 0.39 i0.28 0.28 84.00.29 0.49 0.30 0.30 90.80.33 0.60 0.32 0.32 97.00.38 0.72 0.34 0.34 102.90.42 0.84 0.36 0.36 108.50.46 0.97 0.38 0.38 113.80.50 1.11 !0.40 0.40 118.80.54 1.25 0.41 0.41 123.70.58 1.40 0.43 0.43 128.40.63 1.55 0,44 0.44 132.90.67 1.71 0.46 0.46 137.20.71 1.87 0.47 0.47 141.50.75 2.04 0.49 0.49 145.60.79 2.21 0.50 0.50 149.50.83 2.39 0.51 0.51 153.40.88 2.57 0.52 0.52 157.20.92 2.76 0.54 0.54 160.90.96 2.95 0.55 0.55 164.51.00 3.14 0.56 0.56 168.1Note:1. "Resulting Value" is the lesser or the weir flow and the orifice flow.Page 3-34 AAR EVADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportTable 3-11: Two 6-Inch-Diameter Roof Drains Capacity_ _ _ _ " ___. ___ _ o m p ariso n and R esulting Flow " ". ..... ....Oepth Weir Flow Orifice Flow Resulting Value Resulting Value 1(ft) (cfs) (cfs) (cfs) (cubic ft per 5 minutes)0.00 0.00 0.00 0.00 0.00.04 0.08 0.51 0.08 24.00.08 0.23 0.73 0.23 68.00.13 0.42 0.89 0.42 125.00.17 0.64 1.03 0.64 192.40.21 0.90 1.15 0.90 268.90.25 1.18 1.26 1.18 353.40.29 1.48 1.36 1.36 408.50.33 1.81 1 1.46 1.46 436.70.38 2.16 1.54 1.54 463.20.42 2.53 1.63 1.63 488.20.46 2.92 1.71 1.71 512.00.50 3.33 1.78 1.78 534.80.54 3.76 I 1.86 1.86 556.60.58 4.20 1.93 1.93 577.70.63 4.66 1.99 1.99 597.90.67 5.13 2.06 2.06 617.50.71 5.62 2.12 2.12 636.60.75 6.12 2.18 2.18 655.00.79 6.64 2.24 2.24 673.00.83 7.17 2.30 2.30 690.40.88 7.71 2.36 2.36 707.50.92 8.27 2.41 2.41 724.10.96 8.84 2.47 2.47 740.41.00 9.42 2.52 2.52 756.31.04 10.02 2.57 2.57 771.91.08 10.63 2.62 2.62' 787.21.13 11.25 2.67 2.67 802.21.17 11.88 2.72 2.72 816.91.21 12.52 2.77 2.77 831.41.25 13.17 2.82 2.82 845.61.29 13.84 2.87 2.87 859.61.33 14.51 2.91 2.91 873.31.38 15.20 2.96 2.96 886.91.42 15.89 3.00 3.00 900.2Note:1. "Resulting Value" is the lesser or the weir flow and the orifice flow.Page 3-35 AARE EVADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportTable 3-12: MSIV West Drains Capacity (Two 5-Inch-Diameter Floor Drains)Comparison and Resulting Flow Depth Weir Flow Orifice Flow Resulting Value'1 Resulting Value'1(ft) (cfs (cs) (fs)(cubic ft per 5(ft)cfs) cfs) cfs)m in utes)0.00 0.00 0.00 0.00 0.00.04 0.07 0.36 0.07 20.00.08 0.19 0.51 0.19 56.70.13 0.35 0.62 0.35 104.10.17 0.53 0.71 0.53 160.30.21 0.75 0.80 0.75 224.10.25 ,0.98 0.88 0.88 262.6,0.29 1.24 0.95 0.95 283.7I0.33 1.51 1.01 1.01 303.20.38 1.80 1.07 1.07 321.60.42 2.11 1.13 1.13 339.00.46 2.44 1.19 1.19 355.60.50 !2.78 1.24 1.24 371.4)0.54 3.13 1.29 1.29 386.60.58 3.50 1.34 1.34 401.20.63 3.88 1.38 1.38 415.20.67 4.28 1.43 1.43 428.90.71 4.68 1.47 1.47 442.00.75 5.10 1.52 1.52 454.90.79 5.53 1.56 1.56 467.30.83 5.97 1.60 1.60 479.50.88 6.43 1.64 1.64 491.30.92 6.89 1.68 1.68 502.90.96 7.37 1.71 1.71 514.21.00 7.85 1.75 1.75 525.21.04 8.35 1.79 1.79 536.11.08 8.86 1.82 1.82 546.71.13 9.37 1.86 1.86 557.11.17 9.90 1.89 1.89 567.31.21 10.43 1.92 1.92 577.4Notes:1. "Resulting Value" is the lesser or the weir flow and the orifice flow.Page 3-36 AARE VADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportTable 3-13: MSIV East Drain Capacity (one 4-Inch-and one 5-Inch Diameter Scupper)4" Scupper4" Scupper ______ " Scupper + 5'ScupperDept Weir Orifice Resulting Resulting Weir Orifice Flow Resulting Resulting Resultingh Flow Flow Value 1 Value 1 Flow Value V'u Value(cubic ft per (cubic ft per (cubic ft per(ft) (cfs) (cfs) (cfs) (ints) Cf s) (cfs) (cfs) 5miue) 5ints0.00 0.00 0.00 0.00 0.0 0.00 0.00 0.00 0.0 0.00.04 0.03 0.11 0.03 8.0 0.03 0.18 0.03 10.0 18.00.08 0.08 0.16 0.08 22.7 0.09 0.25 0.09 28.3 51.00.13 0.14 0.20 0.14 41.7 0.17 0.31 0.17 52.1 93.70.17 0.21 0.23 0.21 64.1 0.27 0.36 0.27 80.2 144.30.21 0.30 0.26 0.26 76.7 0.37 0.40 0.37 112.0 188.70.25 0.39 0.28 0.28 84.0 0.49 0.44 0.44 131.3 215.30.29 0.49 0.30 0.30 90.8 0.62 0.47 0.47 141.8 232.60.33 0.60 0.32 0.32 97.0 0.76 0.51 0.51 151.6 248.70.38 0.72 0.34 0.34 102.9 0.90 0.54 0.54 160.8 263.70.42 0.84 0.36 0.36 108.5 1.06 0.57 0.57 169.5 278.00.46 0.97 0.38 0.38 113.8 1.22 0.59 0.59 177.8 291.60.50 1.11 0.40 0.40 118.8 1.39 0.62 0.62 185.7 304.50.54 1.25 0.41 0.41 123.7 1.57 0.64 0.64 193.3 317.00.58 1.40 0.43 0.43 128.4 1.75 0.67 0.67 200.6 328.90.63 1.55 0.44 0.44 132.9 1.94 0.69 0.69 207.6 340.50.67 1.71 0.46 0.46 137.2 2.14 0.71 0.71 214.4 351.70.71 1.87 0.47 0.47 141.5 2.34 0.74 0.74 221.0 362.50.75 2.04 0.49 0.49 145.6 2.55 0.76 0.76 227.4 373.00.79 2.21 0.50 0.50 149.5 2.77 0.78 0.78 233.7 383.2Page 3-37 AARE VADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation Report4" Scupper4" Scupper ___________5" Scupper + 5"Dept Weir "Orifice Resulting Resulting Weir Orifice Flow 1eutn Resulting Resultingh Flow Flow Value'= Value'z Flow Value Value__________ _______Value(cubic ft per (cubic ft per (cubic ft per(ft) (cfs) (cfs) (cfs) 5 minutes) (cfs) (cfs) (cfs) 5 minutes) 5 minutes)0.83 2.39 0.51 0.51 153.4 2.99 0.80 0.80 239.7 393.20.88 2.57 0.52 0.52 157.2 3.21 0.82 0.82 245.7 402.90.92 2.76 0.54 0.54 160.9 3.45 0.84 0.84 251.4 412.40.96 2.95 0.55 0.55 164.5 3.68 0.86 0.86 257.1 421.61.00 3.14 0.56 0.56 168.1 3.93 0.88 0.88 262.6 430.71.04 3.34 0.57 0.57 171.5 4.17 0.89 0.89 268.0 439.61.08 3.54 0.58 0.58 174.9 4.43 0.91 0.91 273.3 448.31.13 3.75 0.59 0.59 178.3 4.69 0.93 0.93 278.5 456.81.17 3.96 0.61 0.61 181.5 4.95 0.95 0.95 283.7 465.21.21 4.17 0.62 0.62 184.8 5.22 0.96 0.96 288.7 473.4Note: 1. "Resulting Value" is the lesser or the weir flow and the orifice flow.Page 3-38 AARE VADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportTable 3-14: DCT Basins Maximum Ponding Depths Summary (ft)Tablei 3-15:30MSIVuAreasndMaximunutPonding Dafters0Sminute~~ ~ ~and I ?urnpit~ ! 1u~~S~tn>f&I~or adIPmBasinast0,AMSIV West 0,62Page 3-39 AAR EVADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportFigure 3-1: LIP Hyetograph7.006.005.00o3.00a..2.001.000.0010.1 0.5 0.9 1.3 1.8 2.2 2.6 3.0 3.4Time (hours)3.8 4.3 4.7 5.1 5.5 5.9Page 3-40 AA R EVA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportFigure 3-2: FLO-2D Modeled Site FeaturesFigure not to scale.Page 3-41 AARE VADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportFigure 3-3: WSES LIP Locations of InterestAny illegible text for features in this figure are not pertinent to the technical purposes of this document. Figure not to scale.Page 3-42 AARE VADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportFigure 3-4: Relevant NPIS DetailsAny illegible text or features in this figure are not pertinent to the technical purposes of this document. Figure not to scale. (WSES, 2001 a)Page 3-43 AARE EVADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportFigure 3-5: Pipes Connecting the FHB to DCT BasinsF I-~ ~ cec~4~4 ~FHB Sub-Basewnmt i ~ ..-~~RTFCArLP4r2~PL~L47~I..~- i~MLLA~)/~ ~t I~L7I bC~ CIYP F3I~ TI~4 4-{yS~CT~ON A ~LUi ~TAILAny illegible text or features in this figure are not pertinent to the technical purposes of this document. Figure not to scale. (WSES, 1986 and WSES, 1991a)Page 3-44 AARE EVADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportFigure 3-6: Flow Chart Showing Major Steps Involved in Calculating the Site-Specific PMP for LIPcitS~tPage 3-45 AA R E VADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportFigure 3-7: Domain Used to Identify Storms Used in the AnalysisStorm Search DomainWaterford Steam Electric Stationtf~ 8w 9fw w 16 1°w CotPage 3-46 AAR E VA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportFigure 3-8: Locations of Storms Used to Calculate LIP Values for WSESLocations of LIP StormsWaterford Steam Electric Station~~HAMI,$OheWIJUO , Miles 0 100 200 304) 400 600Note: Any illegible text or features in this figure are not pertinent to the technical purposes of this documentPage 3-47 AA R EVADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportFigure 3-9: FHB Air Intake and Exhaust Openings Elev. +1 ft, MSLAny illegible text or features in this figure are not pertinent to the technical purposes of this document. Figure not to scale. (WSES, 2011 lb)Page 3-48 AARE EVADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportFigure 3-10: DCT Basins Contributing Areas Layouto p w tw.....Page 3-49 AAR EVAFigure 3-tDocumentsiNo.:tor1-9227040-000uFigure 3-11: DCT Basins Storage Areas LayoutPage 3-50 AARE VADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportFigure 3-12: MSIV Contributing Areas Layout6 3 ...... 13.. ...Page 3-51 AARE EVADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportFigure 3-13: DCT Basins and FHB Flood Depths-I1 Sump Pump Starting after 30 Minutes1.751.51.25a.0.50.0007.000-51.000 2.000 3.000 4.000Time (hours)Basin A --wDCT Basin B -*4FHB5.0006.000Page 3-52 AARE EVADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportFigure 3-14: DCT Basins and FHB Flood Depths -1 Sump Pump Starting after 0 Minutes[ -[ -[1.751.51.250,I0.510.20imJ(hurs0.000-e--DCT0Basin0 .00 T Basi 0 5B0006HB0Time (hours)-DCT Basin A OCT Basin B -~-FHB7.000Page 3-53 AAR EVADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportFigure 3-15: DCT Basins and FHB Flood Depths -1 Sump Pump and 1 Portable Pump Starting after 30 Minutes1.75 Tr1.51.250.750.560.750-0.0001.000 2.000 3.000 4.000Time (hours)--DCT Basin A ---DCT Basin B -*4FHB5.0006.000e7.000Page 3-54 AARE EVADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportFigure 3-16: DCT Basins and FHB Flood Depths -1 Sump Pump and 1 Portable Pump Starting after 0 Minutes[ 1.5 T____ ______________________1.25Oia.0.750.250.0001.000 2.000 3.000 4.000 5.000 6.000Time (hours)Basin A DCT Basin B 7 age300Page 3-55 AA R E VA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportFigure 3-17: DCT Basins and FHB Flood Depths -1 Sump Pump Starting after 30 Minutes and 1 Portable Pump Starting after 1 Hour1.2 _ _-_ _ _ I- _ _4-a.S0.750 "t -0.000 1.000 2,000 3.000 4,000 5.000 6.000 7.000Time (hours).=-DCT Basin A --.-DCT Basin B ,--4-FHBPage 3-56Page 3-56 AA R EVA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportFigure 3-18: DCT Basins and FHB Flood Depths-I1 Sump Pump Starting after 30 Minutes and 1 Portable Pump Starting after 3 Hours1.5 -_ _ _ _ _1.25 " ______a.-w0.7a-o0.5 -0.000 1.000 2.000 3.000 4.000 5.000 6.000 7.000Time (hours)-.Basin A Basin B -4NIFHBPage 3-57 AARE VADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportFigure 3-19: OCT Basins and FHB Flood Depths -1 Sump Pump Starting after 30 Minutes, 1 Portable Pump Starting after 1 Hour and 1Portable Pump Starting after 3 Hours1.751.51.25a,0.50.20 170.0001.0002.000 3.000 -4.000 --Time (hours)-.DCT Basin A -4DCT Basin B --(--FHB5.0006.0007.000Page 3-58 AA RE VA Document No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportFigure 3-20: DCT Basins and FHB Flood Depths -1 Sump Pump Starting after 0 Minutes and 1 Portable Pump Starting1.5 _________ ________ -t_______1.25 ________40.7'4-'0 IC,00.000 1.000 2.000 3.000 4.000 5.000 6.000 7.000Timea(hours)Page 3-59 AARE VADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportFigure 3-21: MSIV East Flood Depths0.800.700.60A ';n040a._~0.200.10 -0.00-0.0001.000 2.000 3.000 4.000 5.000 6.000 7.000Time (hours)8.00 3-0Page 3-60 AARE EVADocument No.: 51-9227040-000Waterford Steam Electric Station Flooding Hazard Re-Evaluation ReportFigure 3-22: MSIV West Flood Depths0.70-0.60-0.50.0.40 a.0.20.10.1000.000-1.000 2.000 3.000 4.000 5.000 6.000 7.000Time (hours)8.000-6Page 3-61}}
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