NRC 2015-0017, Response to NRC 10 CFR 50.54(f) Request for Information Regarding Near-Term Task Force Recommendation 2.1, Flooding - Submittal of Flooding Hazards Revaluation Report

Response to NRC 10 CFR 50.54(f) Request for Information Regarding Near-Term Task Force Recommendation 2.1, Flooding - Submittal of Flooding Hazards Revaluation Report

ML15071A413
Person / Time
Site:	Point Beach
Issue date:	03/12/2015
From:	Mccartney E Point Beach
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NRC 2015-0017
Download: ML15071A413 (130)

Text

NEXTeraM ENERGV_.

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March 12, 2015 NRC 2015-0017 10 CFR 50.54(f)

U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Point Beach Nuclear Plant, Units 1 and 2 Docket 50-266 and 50-301 Renewed License Nos. DPR-24 and DPR-27 NextEra Energy Point Beach, LLC, Response to NRC 10 CFR 50 .54(f) Request for Information Regarding Near-Term Task Force Recommendation 2.1 , Flooding- Submittal of Flooding Hazards Revaluation Report References :

1. U.S. Nuclear Regulatory Commission , Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Recommendations 2.1, 2.3 and 9.3 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident, dated March 12, 2012 (ML12073A348), and letter Enclosure 2 (ML12056A048)

2. U.S. Nuclear Regulatory Commission, Prioritization of Response Due Dates for Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f)

Regarding Flooding Hazard Reevaluations for Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident, dated May 11 ,

2012 (ML12097A509)

3. David L. Skeen, U.S. Nuclear Regulatory Commission, to Mr. Joseph E. Pollock, Nuclear Energy Institute, Trigger Conditions for Performing an Integrated Assessment and Due Date for Response, dated December 3, 2012 (ML12326A912)

4. NextEra Energy, Inc., 60-Day Response to NRC 10 CFR 50 .54(f) Request for Information Regarding Near-Term Task Force Recommendation 2.1, Flooding , dated January 24, 2013 (ML13028A473)

On March 12, 2012, the NRC staff issued a Request for Information pursuant to Title 10 of the Code of Federal Regulations 50.54(f) regarding Recommendations 2.1, 2.3 and 9.3 of the Near-Term Task Force Review of insights from the Fukushima Dai-ichi accident (Reference 1). of that letter requested submittal of a flooding hazards reevaluation report. By letter dated May 11, 2012 (Reference 2), Point Beach Nuclear Plant, Units 1 & 2, was prioritized as Category 3, requiring submittal of the flooding hazards reevaluation by March 12, 2015. The enclosure to this letter provides the requested report.

NextEra Energy Point Beach, LLC, 6610 Nuclear Road , Two Rivers, WI 54241

Document Control Desk Page 2 The enclosed flooding hazards reevaluation (FHR) report demonstrates that one hazard, Local Intense Precipitation, exceeds the current design basis for Point Beach Nuclear Plant, Units 1 and 2. The results of all other hazards evaluated are bounded by the current licensing basis. An Integrated Assessment will be performed for the Local Intense Precipitation event and will be submitted by March 12, 2017 (Reference 3). Interim actions are not required as the existing station design and procedure actions are adequate to implement the Flexible Coping Capability (FLEX) strategies during a Local Intense Precipitation event.

It should be noted that the FHR report indicates that the station is protected from a current licensing basis maximum precipitation event by natural site drainage. The station is currently implementing modifications to provide additional protection for the Primary Auxiliary Building and Containment facades due to a maximum precipitation event caused by the current licensing basis combination of snowmelt and precipitation. These modifications have not yet been included in the Updated Final Safety Analysis Report (UFSAR). Consequently, the modifications are not reflected in the FHR report.

This letter contains one new regulatory commitment:

1. An Integrated Assessment will be performed for the Local Intense Precipitation event and will be submitted by March 12, 2017.

If you have any questions, please contact Mr. Michael Millen, Licensing Manager, at (920) 755-7845.

I declare under penalty of perjury that the foregoing is true and correct. Executed on March 12, 2015.

Sincerely, D~f)~

(~~r c. M '"'"-rl"~Y Eric McCartney Site Vice President NextEra Energy Point Beach, LLC Enclosure cc: Administrator, Region Ill, USNRC Resident Inspector, Point Beach Nuclear Plant, USNRC Project Manager, Point Beach Nuclear Plant, USNRC

ENCLOSURE NEXTERA ENERGY POINT BEACH, LLC POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2 FLOODING HAZARDS REEVALUATION REPORT FPL-076-FHRPR-002, REVISION 2 127 pages follow

FlLOHDIDJfN<G JHfAZAJRJI))§ RJEJEVAJL1UATll ON JRJEJP>OR'f JF'JP>JL-076-JFJEHRJP>JR-002, RlE V][Slf0 N 2 IN RESPONSE TO THE 10 CFR 50.54(f) INFORMATION REQUEST REGARDING NEAR"TERM TASK FORCE RECOMMENDATION 2.1:

FLOODING for the JP>@nnnt Be~clhl NttncBe~r JP>B~nnt Unnnts ]_ & 2 6610 Nucleat* Road Two RiveJ*s, Wisconsin 54241-9516 Facility Operating License Nos. DPR-24 and DPR-27 Presented to:

NextEm Energy Resources 700 Universe Boulevard Juno Beach, Florida 33408-2683 Prepared by:

Enercon Services, Inc.

1501 Ardmore Boulevard, Suite 200 Pittsburgh, Pennsylvania 15221-4451 March 6, 2015 Printed Name/Title Affiliation Signnture Dnte

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Prepnrel'! Shnun W. Kline, Ph.D./ LRE ENERCON 316/2015 Reviewer: Snndra C. Dinzeo, P.E. I MGR - ENERCON

- -- 3/6/2015 Approvcr:

Site Sponsor:

Gernld E. Williams, P.E. I MGR Wn~ne B. Fromm

- ENERCON NEE

-~ 316/2015

~~.

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding ENERCON NextEra Energy- PBNP March 6, 2015 Excellence-Every project. Every day FPL-076-FHRPR-002, Revision 2 Table of Contents 1.0 PURPOSE ... .. .... ... .... .. .................. .. .......... .... .... .... ... .... .. .. ... ..... .... ..... .. .......... ....... .......................... ... 9 1.1 Background ..... ..... ....... ... ....... .. .. .... ............... ....... ... ......... ........ ... ... ... ... ......... ... .... ..... .. ..... ....... .. ..... 9 1.2 Requested Actions ... .... ... .... .. .... ...... .......... .. ...... .... .... .. ... .......... ........... ......... ... ...... .. ..................... . 9 1.3 Requested Information ..................... .. ....... .. .. .... ... .. .. ...... .. ..... ........... ... .... .. ..................... ............. 10 1.4 Applicable Guidance Docu1nents ......... ................................ ...... ... .. .. ....................... ... ............... . 11 2.0 SITE INFORMATION ...................................... ................................................. ........................... 12 2.1 Datums and Projections .......................... .... ... .. ............................. ........ .. ... ........................... ...... 12 2.1.1 Horizontal Datums and Projections ........ .... .. .. .............................................. .. .............. .. .... 12 2.1.2 Ve1tical Datums .. .. ...... ....... .. ............... ...... .. ...... ...... .. ...... .. ..... ........... .. .... .... ..... ... ............. ... 12 2.1.3 Ve1tical Datmn Conversions .................................................. .. ......................... .. ..... .. ..... .... 13 2.2 PBNP Plant Description ......... ... .. ..... ...... .. ..... ... ..... ..... .. ..... ...... .... ...... ... .. .... ........ .... ...... ... .... ... ... .. 13 2.2.1 PBNP Topography .................................. .......................................... .. ................................ 13 2.3 Flood-Related and Flood Protection Changes to the Licensing Basis since License Issuance ... 14 2.3.1 2012 Flooding Walkdown Summary .... ................ .. .. ........ .. .... ...... .... .. .. .................. .......... .. 14 2.3 .2 Flood Protection Features and Protected Equipment.. ................ .... .. .. .. .. .. .. .. .......... ...... .. .... 15 2.4 Hydrosphere ... ..... .... ........... ................. .. .. .... .. ...................... ... .................. ... .... .... ......... ............... 16 2.4.1 Climate .. .. .. .. .. .. .......................... .... .... ... ......... .. ........... .. .. ...... ..... ....... ........ ........... .. ... ....... .... 16 2.4.2 Rainfall ................... .. ......... ................ ...... .... .. .. .. .. ........ .... ........ .. .. .. .... .......... .... .................... 16 2.4.3 Severe Weather .. .. ................. .... ..... ...... .......................... ...... .. .................. .. ............ ........ .. ... 16 2.4.4 Wind ......... .................. .... ... ... ......... ... ... ... ... ..... ... .... .. ......... ....... ... ..... .... .. .. .... ... .................. ... 17 2.4.5 Ice Storms ...... .. .. ...... .. ................. ... .. ....... ....................................... .. ................................... 17 2.4.6 General Lake Michigan Hydrology .. ........................ .. ...... ........ ............ .. ........ .. .... .. .. .......... 17 3.0 CURRENT LICENSE BASIS FOR FLOODING HAZARDS .............................. .. .. .. .. ............... 20 3.1 CLB- Maximum Precipitation Flood .......... .......... .. ...... ............ .. .. .... ........................................ 20 3.2 CLB- Riverine (Streams and Rivers) Flooding ...................................................... .. ........ .. ....... 20 3.3 CLB- Dam Breaches and Failure Flooding .... ........ ........ .. .............. .. .... .. .... .. ...... .. ..................... 20 3.4 CLB- Lake Michigan Flooding ................................................................................................. 20 3.4.1 Storm Surge Background ............ ... ... ..................... .... ........ .. .... .................. ........................ . 20 3.4.2 Astrono1nical Tides .. ........ .. ............................. .............. .. ......................................... .... .. .... . 21 3.4.3 Maximum Historical Lake Michigan Water Level ................ .. .... .. .. .. ...... .. .. ...... .. .. .. ........... 21 3.4.4 Probable Maximum Windstorm ..... ..... .... .. ..................................................... ..... ..... ........... 21 3.4.5 WaveAction ...................................................... .. ............................................................... 21 3.4.6 Wave Runup ......................................... .. ... ............ .. .. ............ .. ............. .. ...... .. ..................... 21 3.4.7 Maxi1nU1n Stann Surge .................................... .. ........ ........ .... ............... .. ........................... . 22 3.4.8 Seiche ... ... ...... .... ..... ................. ....... ... ........................................... ........... .... ....... ........... .. .... 23 3.5 CLB- Tsunami Flooding ................ .. .......... .... .. ...... .. .. ..... .... ..... .. .. .. ........ ...... .................. ........... 23 3.6 CLB- Ice-Induced Flooding ........................................ .... .... .. ................ .. .. .. .............. ..... .. ......... 23 3 .7 CLB- Chmmel Migration or Diversion Flooding .................................... .. ................................ 24 3.8 CLB- Combined Events Flooding ...... .. .... ...... .. .. .. .. .......................... .. .............. .. .............. .. ....... 24 3.9 CLB -Flooding Protection ................................... .. .................................................................... 24 Page 1 of69

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding ENERCON NextEra Energy- PBNP March 6, 2015 Excellence-Every project. Every day.

FPL-076-FHRPR-002, Revision 2 3 .I 0 CLB - Low Water Effects ..... ............ ..... ... ............ ............................. ......... .......................... ..... 26 3.11 CLB - Hydrostatic, Hydrodynamic, Sediment, and Debris Loading ............ .. ... ..... .. ... .... ...... ..... 26 3.12 CLB- Waterborne Projectiles ................. .. .. ... .. ........ ............. ... ................. .. ......... ....... ............... 26 4.0 FLOODING HAZARDS REEVALUATION ................................................. .... ......... ................. 28 4.1 Local Intense Precipitation ......... .. ....... .................................................... ... ....... ..................... ..... 28 4.1.1 Local Intense Precipitation Intensity and Distribution ............... ... ... ................................... 28 4.1.2 Runoff and Routing Model Overview ......................... ........ .... ....... .............. ....................... 29 4.1.3 Surface Topography Generation ........ .............................. ...... ............................................. 29 4.1.4 Obstructions and Flow Impediments ............................................ .... ................. ................. 29 4.1.5 Surface Infiltration and Roughness Characteristics .......... ........ .................. .. ....... .... .. .... ... .. 30 4.1.6 Storm Drain Network .................................. .. .. .. ....... .. ................................... .... .. .. ......... ..... 30 4.1.7 RunoffModel Scenarios ....................... ... ... .... ......... ...... ...... ........................ ... ... ..... ...... ... ... 30 4.1. 8 Runoff Model Processes and Successful Application Criteria ..... ............... .. ...................... 31 4.1.9 Model Results .... .. ............ ........................................................... ................................ ..... .. . 32 4.2 Riverine Flooding .................................................................................... ........ ...... ....... .............. 33 4.3 Da1n Breaches and Failures .. ............................ ........................................ ..... .. .... .. ...................... 33 4.4 Probable Maximu1n Storm Surge ..... ............................ ....... .. ...... ... .. .. ................ ....... ..... ... .......... 33 4.4.1 Methodology Overview ..................................... ..... ....... ....... ... ...................................... .. ... 33 4.4.2 Development of Model Domain ................ ............... ........ .. .... .. ............................ ............... 34 4.4.3 Model Processes ........................... .... ........ .. ........................ ..................... ... .... .. ................... 36 4.4.4 Physical Parameters and Model Constants .. .......... .................. .. ............. ............ .. .. .... .. ...... 36 4.4.5 Nutnerical Parameters .. ..................... ........... ........................ .. ....... ....................... .... .. ....... .. 38 4.4.6 Antecedent Lake Level .... ....................... .................. ................... ...................... ...... ..... ...... 39 4.4. 7 Probable Maximum Windstorm Development ......................... ........ ....... ..... ........ .. ............ 40 4.4.8 Storm Surge Model Calibration ......................... ... .............. ..... .. ......................................... 41 4.4.9 Probable Maximum Storm Surge Methodology .... ........... ..... ........................... ... .. ............. 44 4.4.1 0 Storm Surge Results ... ................. ........................ .... .. .... ....... ..... ................................. ... ... ... 4 7 4.5 Seiche ...... ..... .. .... ............... ............. .......... .......... ...................... .. .. .............................. .. ............ .. . 48 4.5.1 Squall Line Event Development ............... .. ..... ....... ... ................................ ...... ..... .. .... ...... .. 48 4.5.2 Model Development. ................................. .... ........... .. ............................. ....... ..... .. .... .......... 49 4.5.3 Seiche Model Validation ......................... .............................. ............................ .. .... ............ 49 4.5.4 Maximutn Seiche Results ... ....... ... ............................... ........... ....... ... ................................... 49 4.6 Probable Maxitnum Tsunmni ............ .. .. .......... .... ........ ........................ .. ... .. ..... ..... .. ..................... 50 4.7 Ice-Induced Flooding and Effects .... .... ... ... ......................................... ........ .. ... .... ... .. .................. 50 4.7.1 Ice Cover ...... .................. ...... ... ........ ..... ............................ ...... ..... ................ ........................ 50 4.8 Channel Migration or Diversion ........................... .. .. .. .... ....... ....................... ........ ... ... ..... .. ......... 51 4.9 Cotnbined Events Flooding ... ... ............................ .. .... ...... ........... .... .................... ....... .. .. .. .. ... ...... 51 4.10 Low Water Effects ................ ............ .. ..... ... .... ...................................... .. .. ....... ..... .. .............. ..... . 51 4.11 Hydrostatic, Hydrodynamic, and Sediment Loading ... .. ...... ....... ...................... .......................... 51 4.11.1 Local Intense Precipitation Loading ....... .. ........ ... .. ..... ................................... .. .. ........... ...... 52 4.11.2 Probable Maximum Storm Surge Loading ......... ...... .................................. .. ....... ............... 53 4.12 Debris and Waterborne Projectiles ....... ............................... ................ ..... .. .............................. .. 53 5.0 COMPARISON WITH CURRENT DESIGN BASIS .... .... ...... .. .......................... ..... ... ................ 55 Page 2 of69

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding F.:r ENE R C 0 N NextEra Energy- PBNP March 6, 2015 Excellence-Every project. Every day.

FPL-076-FHRPR-002, Revision 2 5.1 Precipitation Flooding ..... ....... ... ........ ...... ..... .... ...... ............ ....... ... ..... ............. ....... ....... ......... ...... 55 5.2 Riverine Flooding ........................................ .. .... ..... ..... .. ................................................. ..... ... .... 55 5.3 Dam Breaches and Failures .................... .. .. ... ..... .... .. ....................................... .. .......................... 55 5.4 Storm Surge ..................................... .... ... ........ ... .............................. .. ..... .... .. ........ .. ........ ...... .. .... 55 5.5 Seiche ................................. ... ..... ...... .......... ..... ................... .......................... ............................... 56 5.6 Tsunami Flooding .... .. ... .......................... ..... ................................ .......... ....... ... .. ..... .................... 56 5.7 Ice-Induced Flooding ...... .. .......... .. .......................................... .................. .. .... ............................ 56 5.8 Channel Migration or Diversion Flooding .................... .... .. ............ ........ .................................... 56 5.9 Combined Events Flooding ............... ............... ............................ .. .. .. .... .... ...... .......... ... ........... ... 56 5.10 Low Water Effects ......................................................................................... ............................. 56 5.11 Hydrostatic, Hydrodynamic, and Sediment Loads ...... ............................................................ .. . 57 5.12 Debris and Waterborne Projectiles ................................................................................... .. ..... ... 57 5.13 Sutnmary of Comparison .... .................................................... ...... ... ..... ...................................... 57 6.0 INTERIM EVALUATION AND ACTIONS .................. .. .. ................ .......................................... 58 6.1 Local Intense Precipitation .. .. ............ .......... ....... ......................................................................... 58 6.2 Riverine Flooding .................. .. ....... ..... ......... ......................................... ......................... ..... .. ..... 59 6.3 Datn Breaches and Failures ...................................................... .... .......................................... .. ... 59 6.4 Storm Surge ... ... .. ... ................................................... .. .. .... ... .. ..... .... ........ .. ........................ .. ........ 59 6.5 Seiche .... .............. .................................................................... .. .. .. .............................................. 60 6.6 Tsunami .................................. ... .. .. .......... .... .. .. ................................... .... .. .. ...... ....... ... .. .... ........... 60 6.7 Ice-Induced Flooding .................................................... ... ......... .. ...... .......................................... 60 6.8 Channel Migration or Diversion Flooding ............... ......... ........... ... ............................................ 60 6.9 Combined Events Flooding ........................................... .. ........... .... .. .......................................... . 60 6.10 Low Water Effects ......... .. ......... ............. .. .. ..................................................... .. .......................... 60 6.11 Hydrostatic, Hydrodynamic, and Sediment Loads ........ .................... ......................................... 60 6.12 Debris and Waterborne Projectiles ................................ .. ...... .. ................................................... 60 7.0 ADDITIONAL ACTIONS ............................................ ........... ....... ... ................................ .. .. ...... . 61

8.0 REFERENCES

... .. ............... .................................................... .. .......... .. ............................. ........... 62 Page 3 of69

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding ENERCON NextEra Energy- PBNP March 6, 2015 Excellence-Every project. Every day.

FPL-076-FHRPR-002, Revision 2 List of Tables Table 2.1 Vertical Datum Conversions Table 3.1 CLB Precipitation Flood Event Maximum WSELs at POls Table 3.2 CLB Wave Runup Table 4.1 Site-specific Subhourly PBNP LIP Precipitation Depths Table 4.2 Site-Specific LIP Scenario A and Scenario B Maximum Flow Depths and WSELs at POls Table 4.3 Summary of Lake Level Frequency Analysis Results Table 4.4 Potential PMWS Scenarios Table 4.5 NOAA Tide and Water Level Stations Considered for Calibration and Validation Table 4.6 NOAA Buoy Stations Considered for Calibration and Validation Table 4.7 Delft3D-FLOW Storm Surge Calibration Simulations Table 4.8 Delft3D Final Calibrated Parameter Values Table 4.9 Summary of Parameters for Delft3D-FLOW Model Table 4.10 Summary of Parameter for Delft3D-WAVE Model Table 4.11 Peak WSEL from Synoptic Screening Events Table 4.12 PMSS Results at PBNP Table 4.13 Peak Seiche SWL from Squall Line Events Table 4.14 Low Water SWL from Synoptic and Squall Line Events Table 4.15 Hydrostatic and Hydrodynamic Loads during LIP Event Table 4.16 Waterborne Projectile Debris Impact Forces and Pressures Table 5.1 Comparison of CLB and FHR Flooding Levels by Mechanism and Component List of Figures Figure 2.1 PBNP Site Location Figure 4.1 PBNP Site Features Figure 4.2 PBNP LIP Hyetographs Figure 4.3 PBNP DTM Elevations Figure 4.4 PBNP Manning' s Roughness Coefficient Spatial Distribution Figure 4.5 PBNP Door Locations Figure 4.6 Direct Drainage Area to PBNP Figure 4.7 LIP Maximum Flow Depths - Scenario A Figure 4.8 LIP Maximum Flow Depths- Scenario B Figure 4.9 LIP TB Door 13 Water Depth Time Series- Scenario B Page 4 of69

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding F. r ENERCON NextEra Energy- PBNP March 6, 2015 Excellence-Every project. Every day.

FPL-076-FHRPR-002, Revision 2 Figure 4.10 Delft3D-FLOW Representation of Lake Michigan and Lake Huron Figure 4.11 Delft3D-FLOW Representation ofPBNP Nearshore Figure 4.12 NOAA Water Level Stations Considered for Calibration and Validation Figure 4.13 NOAA Buoy Stations Considered for Calibration and Validation Figure 4.14 NOAA Station 9087068 Final Calibration near PBNP Figure 4.15 NOAA Buoy 45022 Final Calibration in Shallow Water Figure 4.16 NOAA Station 9087068 Water Surface Elevation for the 1985 Validation Event Figure 4.17 NOAA Station 9087072 Water Surface Elevation for the 1990 Validation Event Figure 4.18 CJON Sensitivity Analysis Results for NOAA Buoy 45022 Figure 4.19 Depth-Induced Breaking Sensitivity (y = 0.73) for NOAA Buoy 45022 Figure 4.20 Depth-Induced Breaking Sensitivity (y = 0.55) for NOAA Buoy 45022 Figure 4.21 Nearshore Grid 4 Showing Observation Point Locations Figure 4.22 Wave Breaking Locations for PMWS (Scenario 13) with Adjusted Wind Fields Figure 4.23 Coefficient for Calculation of Overwater Wind Speed Figure 4.24 CDF of Observed Air and Water Temperature Differences at NOAA Buoy 45007; 95%

Exceedance (Blue Line)

Figure 4.25 Peak PMSS SWL at PBNP Figure 4.26 PMSS Results and Wave Runup on a Gently Sloping Impermeable Surface - South Approach Figure 4.27 Peak PMSS Inundation Map at PBNP Figure 4.28 Lake Huron Observed Versus Computed Values for July 13, 1995 Derecho Event Figure 4.29 Modeled Seiche Amplitudes near PBNP for Maximized May 31, 1998 Derecho Event Figure 4.30 Historical Tsunami Runup and Events near PBNP Figure 4.31 Historical Earthquake Events near PBNP Acronyms and Abbreviations AFW Auxiliary Feedwater ANSI/ANS American National Standards Institute and American Nuclear Society AOP Abnormal Operating Procedure ASCE American Society of Civil Engineers CDF Cumulative Distribution Function CEM Coastal Engineering Manual CFL Courant-Friedrichs-Lewy CFR Code of Federal Regulations Page 5 of69

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding ENERCON NextEra Energy- PBNP March 6, 20 I 5 Excellence-Every proj ect. Every day.

FPL-076-FHRPR-002, Revision 2 CLB Current License Basis COLA Combined License Application CWPH Circulating Water Pump House DTM Digital Terrain Model DIAC Daily Ice Analysis Charts ESP Early Site Permits ESRI Environmental Systems Research Institute FHR(R) Flooding Hazards Reevaluation (Report)

FLEX Flexible Coping Capability GCS Geographic Coordinate System HMR Hydrometeorological Repmi IA Integrated Assessment IGLD55 International Great Lakes Datum of I 955 IGLD85 International Great Lakes Datum of I 985 ISG Interim Staff Guidance JLD Japan Lessons-Learned Project Directorate JONSWAP JOint No1th Sea WAve Project LIP Local Intense Precipitation NAD27 No1th American Datum of 1927 NAD83 No1th American Datum of 1983 NAVD88 North American Ve1tical Datum of I988 NED National Elevation Dataset NEE NextEra Energy NEI National Energy Institute NGDC National Geophysical Data Center NOAA National Oceanographic and Atmospheric Administration NRC Nuclear Regulatory Commission NSE Nash-Sutcliffe (Model Quotient) Efficiency NTTF Near-Term Task Force NWS National Weather Service PAB Primary Auxiliary Building PBNP Point Beach Nuclear Plant Units 1 & 2 PMF Probable Maximum Flood Page 6 of69

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding ENERCON NextEra Energy- PBNP March 6, 2015 Excellence-Every project. Every day.

FPL-076-FHRPR-002, Revision 2 PMP Probable Maximum Precipitation PMSS Probable Maximum Storm Surge PMT Probable Maximum Tsunami PMWS Probable Maximum Windstorm POI Point oflnterest RFI Request for Information RMP Routine Maintenance Procedure RMSE Root Mean Square Error sco (Wisconsin) State Cmiographer's Office SSCs Structures, Systems and Components SWAN Simulating WAves Nearshore SWL Still Water Level TB Turbine Building (Hall)

The Lake Lake Michigan UFSAR Updated Final Safety Analysis Report UHS Ultimate Heat Sink USACE U.S. Army Corps of Engineers USGS U.S. Geological Survey USNIC U.S. National Ice Center WISCRS Wisconsin Coordinate Reference Systems WSEL Water Surface Elevation Units of Measure Degrees Fahrenheit ac-ft Acre-feet ac Acres ft Feet ft/s Feet per second hr Hours in. Inches in. Hg Inches of Mercury kg Kilogram knots Nautical miles per hour kWe Kilowatt -electric Page 7 of69

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding NextEra Energy- PBNP ENERCON March 6, 2015 Excellence-Every proj ect. Every day. FPL-076-FHRPR-002, Revision 2 MW Megawatt MWe Megawatt-electric m Meters mls Meters per second mbar Millibars (of pressure) mi Miles min Minutes mph Miles per hour lbs Pounds pcf Pounds per cubic foot psf Pounds per square foot s Seconds yr Years Page 8 of69

NTTF Recommendation 2.I (Hazard Reevaluations): Flooding ENERCON NextEra Energy- PBNP March 6, 20 IS Excellence-Every project. Every doy FPL-076-FHRPR-002, Revision 2 1.0 PURPOSE This report provides the NextEra Energy (NEE) Point Beach Nuclear Plant Units I and 2 (PBNP) response to the U.S. Nuclear Regulatory Commission's (NRC's) March I2, 20I2 Request for Information (RFI) pursuant to the post-Fukushima Near-Term Task Force (NTTF) Recommendation 2.1 Flooding Hazards Reevaluation (FHR) of PBNP.

1.1 Bacl<ground In response to the Fukushima Dai-ichi nuclear facility accident resulting from the March 1I, 20I1 earthquake and subsequent tsunami, the NRC established the NTTF to conduct a systematic review of NRC processes and regulations, and to make recommendations to the NRC for its policy direction. The NTTF rep01ted a set of recommendations that were intended to clarifY and strengthen the regulatory framework for protection against natural phenomena.

On March I2, 2012, the NRC issued an information request pursuant to Title 10 of the Code of Federal Regulations (CFR) Part 50, Section 50.54(t) (NRC, 2012) which included Enclosures I through 6, inclusive:

1. NTTF Recommendation 2.1: Seismic;

2. NTTF Recommendation 2.1: Flooding;

3. NTTF Recommendation 2.3: Seismic;

4. NTTF Recommendation 2.3: Flooding;

5. NTTF Recommendation 9.3: Emergency Preparedness; and

6. Licensees and Holders of Construction Permits.

In accordance with Enclosure 2 of the NRC I 0 CFR 50.54(t) letter request (NRC, 20 12), licensees are required to reevaluate the flooding hazards at their sites against present-day regulatory guidance and methodologies being used for early site permits (ESP) and combined license applications (COLA).

1.2 Requested Actions Per Enclosure 2 ofthe NRC 10 CFR 50.54(t) letter request (NRC, 2012):

"Addressees are requested to pe1jorm a reevaluation of all appropriate external flooding sources, including the effects ji"Oln local intense precipitation on the site, probable maximum flood (P.A1F) on stream and rivers, storm surges, seiches, tsunami, and dam failures. It is requested that the reevaluation apply present-day regulatmy guidance and methodologies being used for ESP and COL reviews including current techniques, sofhvare, and methods used in present-day standard engineering practice to develop the flood hazard. The requested information will be gathered in Phase I of the NRC staff's two phase process to implement Recommendation 2.1, and will be used to identify potential vulnerabilities.

Page 9 of69

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding

~. Jl E N E RC 0 N NextEra Energy- PBNP March 6, 2015 Excellence-Every proj ect. Every day.

FPL-076-FHRPR-002, Revision 2 For the sites where the reevaluated flood exceeds the design basis, addressees are requested to submit an interim action plan that documents actions planned or taken to address the reevaluated hazard with the hazard evaluation.

Subsequently, addressees should peJform an integrated assessment of the plant to identifY vulnerabilities and actions to address them. The scope of the integrated assessment report vvill include fit!! power operations and other plant configurations that could be susceptible due to the status of the flood protection features. The scope also includes those features ofthe ultimate heat sinks (UHS) that could be adversely affected by the flood conditions and lead to degradation of the flood protection (the loss of UHS fi'om non-flood associated causes are not included). It is also requested that the integrated assessment address the entire duration of the flood conditions. "

NEE PBNP submitted a 60-day response letter (Letter NRC-2012-0027) to the NRC titled, "NextEra Energy Point Beach, LLC's 60-Day Response to NRC Letter, Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Recommendations 2.1.2.3, and 9.3, of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident: dated March 12, 20 12," dated May I 0, 2012 (NEE, 20 12a). In the letter, NEE PBNP stated intentions regarding the RFI.

1.3 Requested Information This report provides the following requested information for PBNP, in accordance with Enclosure 2 of the NRC 10 CFR 50.54(f) letter request (NRC, 2012) :

a. Site information related to the flood hazards. Relevant structures, systems and components (SSCs) important to safety and the UHS are included in the scope of this reevaluation, and pertinent data concerning these SSCs are also included. Other relevant site data include the following:

i. Detailed site information (both designed and as-built), including present-day site layout, elevation of pe1tinent SSCs impmtant to safety, site topography, as well as pertinent spatial and temporal datasets (Section 2.0);

ii. Current design basis flood elevations for all flood-causing mechanisms (Section 2.3 .2);

iii. Flood-related changes to the licensing basis and any flood protection changes (including mitigation) since license issuance (Section 2.3);

iv. Changes to the watershed and local area since license issuance (Section 2.4);

v. Current license basis (CLB) flood elevations for all flood-causing mechanisms (Section 3.0);

and VI. Additional site details, as necessary, to assess the flood hazards (i.e., bathymetiy, walkdown results, and other pettinent data).

b. Evaluations of the flood hazm:ds for each flood-causing mechanism, based on present-day methodologies and regulatory guidance. Analyses are provided for each flood-causing mechanism that may impact the site, including local intense precipitation (LIP) and site drainage, flooding in streams and rivers, dam breaches and failures, storm surge and seiche, tsunami, channel migration or diversion, and combined effects. Mechanisms that are not applicable at the site may be screened Page 10 of69

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding ENERCON NextEra Energy- PBNP March 6, 2015 Excellence-Every project. Every day. FPL-076-FHRPR-002, Revision 2 out; however, justification should be provided. A basis will be provided for inputs and assumptions, methodologies and models used including input and output files, and other pe1tinent data (Section 4.0).

c. Comparison of current and reevaluated flood-causing mechanisms at the site. An assessment of the current design basis flood elevation to the reevaluated flood elevation for each flood-causing mechanism will be provided. This will include how the findings from Enclosure 2 of the 10 CFR 50.54(f) letter (i.e., NTTF Recommendation 2.1 FHR) supp01t this determination. If the current design basis flood bounds the reevaluated hazard for all flood-causing mechanisms, how this finding was determined will be included (Section 5.0).

d. Interim evaluation and actions taken or planned to address any higher flooding hazards relative to the design basis, prior to completion of the integrated assessment described below, if necessary (Section 6.0).

e. Additional actions beyond Requested Information Item l.d taken or planned to address flooding hazards, if any (Section 7.0).

1.4 Applicable Guidance Documents The following documents were used as guidance in performing the FHR analyses:

1. ANSI/ANS (1992), American National Standards Institute and American Nuclear Society (ANSI/ANS), "Determining Design Basis Flooding at Power Reactor Sites," ANSI/ANS-2.8-1992, La Grange Park, Illinois, July 28, 1992;

2. NRC (1977), "Design Basis Floods for Nuclear Power Plants," Regulatory Guide 1.59, Revision 2, Washington, D.C., August 1977, with errata dated June 30, 1980;

3. NRC ( 1978), "Standard Format and Content of Safety Analysis Reports for Nuclear Power Plants,"

Regulatory Guide 1.70, Revision 3, Washington, D.C., 1978;

4. NRC (2007), "Standard Review Plan for the Review of Safety Analysis Rep01ts for Nuclear Power Plants: L WR Edition," NUREG-0800, Washington, D.C., March 2007;

5. NRC (2009), "Tsunami Hazard Assessment at Nuclear Power Plant Sites in the United States of America Final Rep01t," NUREG/CR-6966, PNNL-17397, Washington, D.C., March 2009;

6. NRC (2011), "Design-Basis Flood Estimation for Site Characterization at Nuclear Power Plants in the United States of America," NUREG/CR-7046, Washington, D.C., November 2011;

7. NRC (20 13a), "Guidance for Performing a Tsunami, Surge and Seiche Hazard Assessment," Japan Lessons-Learned Project Directorate (JLD), Interim Staff Guidance (ISG), JLD-ISG-2012-06, Revision 0, January 4, 2013; and

8. NRC (2013b), "Guidance for Assessment of Flooding Hazards Due to Dam Failure,"

JLD-ISG-2013-01, Revision 0, July 29, 2013 .

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FPL-076-FHRPR-002, Revision 2 2.0 SITE INFORMATION PBNP is located in Manitowoc County in east-central Wisconsin on the western shore of Lake Michigan (the Lake), approximately 30 mi southeast of Green Bay and about 90 mi north-northeast of Milwaukee.

The site comprises approximately 1,260 ac owned by NEE. Farming is the predominant activity in this sparsely populated area of the state. The plant is situated in a productive dairy farming and vegetable canning region; however, heavy industry occurs to the south in Two Rivers and Manitowoc, and to the west in the Fox River Valley. Cooling water is drawn from an intake crib located 1,750 ft offshore in the Lake.

Figure 2.1 depicts the site location (NEE, 20 12c).

2.1 Datums and Projections Various horizontal and vertical datums and mapping projections are referenced throughout this rep01t. This section describes the horizontal and vettical datums and mapping projections used, their definitions and relationships, and the methods used to convett fi*om one datum or projection to another.

2.1.1 Horizontal Datums and Projections A horizontal datum is a system which defines an idealized surface of the eatth for positional referencing.

Two N01th American horizontal datums are used currently: the Nmth American Datum of 1927 (NAD27) and the Nmth American Datum of 1983 (NAD83). Latitude and longitude are typically used to identify location in spherical units.

A map projection is a mathematical transformation that convetts a three-dimensional (spherical) surface onto a flat, planar surface. Each projection produces a distmtion. Depending on their intended use, projections are chosen to preserve different relationships of characteristics between features. Projections in the United States are typically defined as State Plane coordinate systems with units of N01thing and Easting. The United States is divided into many State Plane maps, and large states can be defined by several maps. PBNP is within the extents of the Wisconsin South State Plane projection.

The PBNP site topographic and bathymetric surveys were performed in 2013 and 2014, respectively (NEE, 2014a). Both surveys use the Wisconsin Coordinate Reference Systems (WISCRS) of Manitowoc County horizontal projection (NEE, 2014a). The de facto horizontal geodetic datum and adjustment for WISCRS is NAD83 (SCO, 2012) .

2.1.2 Vertical Datums There are two types ofvettical datums: tidal and fixed. Fixed datums are reference level surfaces that have a constant elevation over a large geographical area. Tidal datums are standard elevations that are used as references to measure local water levels. Because of the negligible tidal oscillations in the Great Lakes, fixed datums are used near PBNP. The following is a list of datums referenced in this rep01t:

• International Great Lakes Datum of 1955 (IGLD55)- Fixed datum specific to the Great Lakes, referenced to mean water level at Pointe-au-Pere (Father Point), Rimouski, Quebec, Canada, over the period 1941 to 1956 (USACE, 1991).

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• International Great Lake Datum of 1985 (IGLD85)- Fixed datum specific to the Great Lakes, also referenced to the tide station and benchmark at Pointe-au-Pere (Father Point), Rimouski, Quebec, Canada over the period 1982 to 1988 . IGLD85 replaced IGLD55 in January 1992 (USACE, 1991).

• Nmth American Ve1tical Datum of 1988 (NA VD88)- Fixed vertical control datum determined by geodetic leveling, referenced to the tide station and benchmark at Pointe-au-Pere (Father Point),

Rimouski, Quebec, Canada (NOAA, 2013).

• PBNP Plant Datum (Plant Datum) - Fixed vertical datum where zero elevation is equivalent to

+580.2 ft-IGLD55 and +580.9 ft-IGLD85 (NEE, 2012c). The CLB, historical site survey drawings, and PBNP building structural elevations typically refer to this datum.

2.1.3 Vertical Datum Conversions Where required, ve1tical transformations were performed using the conversions shown in Table 2.1 (NEE, 2012c). Elevations throughout this repmt will be repmted in both ft-NA VD88 and ft-Plant Datum.'

Based on Table 2. 1, 0.0 ft-Plant Datum is equivalent to +581.3 ft-NAVD88.

2.2 PBNP Plant Description The reactors at PBNP are Westinghouse-designed, pressurized light-water moderated and cooled systems.

Unit 1 commenced commercial operation in December 1970; Unit 2 began commercial operation in October 1972. Each unit was originally licensed at a maximum core thermal power output of 1,518.5 MW.

Each steam and power conversion system, including its turbine generator, was originally designed to permit generation of 523.8 MW of gross electrical power. Each unit underwent a low pressure turbine retrofit modification which increased the unit design output to 537,960 kWe. In 2003, a measurement unce1tainty recapture power uprate was performed increasing each unit's rated thermal power level to 1,540 MW. In 201 0, an extended power up rate resulted in Units 1 and 2 increasing their output to 1,800 MW and approximately 640 MWe (NEE, 2012c).

2.2.1 PBNP Topography The ground surface at PBNP is gently rolling to flat with elevations varying from +584.3 to

+639.3 ft-NA VD88 (+3 to +58ft-Plant Datum). In the area around the plant, the land surface either slopes from west to east towards the Lake or to the north and south to divert runoff away from the plant. A topographic high point just to the west of the switchyard prevents any runoff inland of the plant from affecting plant operations (NEE, 2012c).

In relation to the Lake, a majority of the plant grounds are located at +607.3 ft-NA VD88

(+26 ft-Plant Datum). The only exception to this is the area near the Circulating Water Pump House (CWPH) where the plant draws its circulating water from the Lake and has a ground floor elevation of

+588.3 ft-NA VD88 (+7 ft-Plant Datum). On the east side of PBNP, the service roads slope down from

+607.3 ft-NA VD88 (+26 ft-Plant Datum) to around +588 .3 ft-NA VD88 (+7 ft-Piant Datum) near the 1

Note that the storm surge and seiche numerical model (Section 4.4) is set in a metric model datum, such that 0 m-Model Datum is equivalent to the 100-yr maximum Lake Michigan water level (Section 4.4.6). Results from the storm surge model were then conveiied to ft-NA VD88 and ft-Piant Datum for repmiing purposes.

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FPL-076-FHRPR-002, Revision 2 CWPH. The next closest structure to the Lake is the Units I and 2 Turbine Building (TB), approximately 100 ft inland from the CWPH. The ground floor elevation of the TB is +589.3 ft-NA VD88

(+8ft-Plant Datum) (NEE, 2012b).

2.3 Flood-Related and Flood Protection Changes to the Licensing Basis since License Issuance Since the initial license, there have been many changes made to the barriers and to the administrative protections for the postulated floods. This section begins with the 2012 Flooding Walkdown Repmt, its findings and the changes since that time. These changes reflect a fundamental change to the protection strategy for the wave run up.

2.3.1 2012 Flooding Walkdown Summary NEE submitted a Flooding Walkdown Report, dated November 14, 2012, in response to the 50.54(£)

information request regarding NTTF Recommendation 2.3 : Flooding for PBNP (NEE, 2012b). The walkdowns were performed in accordance with National Energy Institute (NEI) 12-07 (Revision 0-A),

"Guidelines for Performing Verification of Plant Flood Protection Features," dated May 2012 and endorsed by NRC on May 31,2012 (NEI, 2012).

Configuration and procedures were compared to the flood protection features credited in the CLB documents for external flooding events. Site-specific features credited for protection and mitigation against external flooding events were identified and evaluated. The results of the walkdown are summarized below.

2.3.1.1 Reasonable Simulations The only reasonable simulation conducted during the 2012 Flooding Walkdown was the installation ofthe temporary concrete jersey barriers as directed by a now-obsolete site procedure. Six barriers were installed on the south side to demonstrate the arrangement; only three barriers were installed on the nmth side due to constraints from construction occurring in the area at the time. No challenges to the time window or site resources needed for completion of the task were noted (NEE, 2012b).

2.3.1.2 Inspection Deficiencies and Corrective Actions The flooding walkdown resulted in the following inspection deficiencies and resulting corrective actions (NEE, 2012b):

• The concrete jersey barriers installed at the CWPH did not extend far enough to the nmth and south to provide a barrier up to +590.3 ft-NA VD88 (+9.0 ft-Plant Datum). Also due to uneven ground and features on the barriers, some gaps existed in the installed configuration. Work requests were written to add additional barriers and pour a concrete pad to correct these issues. This strategy was subsequently revised in October 2014 as discussed in Section 2.3.2.

• The site procedure for the installation of the concrete jersey barriers was found to be deficient. It did not identify that the barriers were being installed in a 8.5 .b staging area and also did not provide pe1tinent information for the support equipment that would be needed. Procedure changes were made to address these issues as well as institute a regular check on the staging condition of the barriers. This strategy was subsequently revised in October 2014 as discussed in Section 2.3 .2.

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FPL-076-FHRPR-002, Revision 2

• The control panel and battery for the diesel fire pump in the CWPH were below +590.3 ft-NA VD88

( +9.0 ft-Plant Datum). The control panel, which also has circuitry for the battery, contains electrical components at +589.68 ft-NA VD88 (+8.375 ft-Plant Datum) which is below the flood height of

+589.72 ft NA VD88 (+8.42 ft-Plant Datum). The Updated Final Safety Analysis Report (UFSAR) was updated to credit installed floor dampers for external as well as internal flooding. This reduced the flood height within the CWPH to +589.05 ft-NA VD88 (+7 .75 ft-Plant Datum).

• A catch basin in the plant yard near the northwest corner of the Unit 2 Fayade Building was covered with a metal plate. This plate was removed, and procedural controls to prevent this condition from reoccurring were evaluated.

• The UFSAR states that PBNP has nmth and west interceptor ditches outside of the plant yard to divett runoff to the Lake. The west side interceptor ditch runs between the plant yard and switchyard, but is obstructed by newly installed equipment and is not continuous. The nmth side ditch was not found. The UFSAR was updated to replace the nmthern interceptor ditch with the storm drain system, and to contain a reevaluation of the drainage near the western interceptor ditch.

The UFSAR was subsequently revised to remove credit for the storm drain system and west interceptor ditch as these features were conservatively not credited in the design basis maximum precipitation analysis.

• There were several instances of inadequate drainage ditch maintenance, including pattially obstructed culverts and some cases of drainage ditches needing to be cleared out or regraded. The maintenance program and suppotting documentation have been updated to accurately reflect the drainage ditch configuration on site and ensure its functionality. The ditches and culvetts have been cleaned under the Work Order process where the inspection criteria were not met. Ditches and culverts were conservatively not credited in the design basis maximum precipitation analysis.

2.3.1.3 Flood Protection Compliance PBNP was found to be in compliance with its flood protection requirements per the CLB upon completion of corrective actions for the above deficiencies (NEE, 2012b). However, an improved flood protection strategy was adopted in October 2014 (NEE, 20 15a; NEE, 20 14b; NEE, 20 14c) which is outlined in Section 2.3.2 below.

2.3.2 Flood Protection Features and Protected Equipment The changes to the external flood strategy in October 2014 began with a clear definition ofthe CLB flood.

The licensing basis at PBNP requires mitigation of design basis floods in rooms with SSCs impmtant to safety.

2.3.2.1 Protection against Wave Run up The CLB maximum wave runup elevation on a vertical structure is +589.72 ft-NA VD88

(+8.42 ft-Plant Datum). A duration for this CLB flood is not defined (NEE, 20 14b). Protection to

+590.3 ft-NA VD88 (+9.0 ft-Plant Datum) is provided by temporary barriers installed at the entrances to the CWPH and TB.

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NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding NextEra Energy- PBNP ENERCON March 6, 2015 Excellence-Every project. Every day. FPL-076-FHRPR-002, Revision 2 The site layout, consisting of the intake structure and rip-rap bank topography, are credited in the flooding evaluations, which demonstrate that the calculated flood level is bounded by the license basis flood level of +9.0 feet. Protection to +9.0 feet is provided by procedurally driven installation of temporary barriers at entrances to the CWPH and TB. When the Lake level exceeds administratively controlled limits, both units are brought to cold shutdown and barriers are installed. The Circulating Water, Condensate and Feedwater Systems are secured prior to installation of barriers at the TB doors/flood dampers in order to eliminate the major sources of internal flooding while the TB relief paths are blocked.

There are no openings in the CWPH walls, other than tight fitting doors, that have a bottom elevation less than +9.0 feet. In addition, storm drains are provided outside each of the CWPH doors. The TB, which is the structure next closest to the Lake, is more than 100ft from the top of the bank. The combination of this distance, the shoreline riprap and the storm drains mitigate Lake effect flooding.

2.3.2.2 Protection against Maximum Precipitation Flood The CLB maximum precipitation flood event is defined as the combined volume of water from the water content of snow in late March with a 50-yr recurrence fi*equency and the volume of water from a 6-hr rainfall with a 50-yr recurrence frequency. The topography of the site allows for the adequate natural drainage to remove the runoff and limit ponding near external access points to safety-related equipment (NEE, 2014b).

2.4 Hydrosphere 2.4.1 Climate The continental climate at PBNP is influenced by the storms which move eastward along the nmthern tier of the United States and by those that move nmtheastward fi*om the southwestern part of the country to the Great Lakes. However, the climate is modified by the Lake. During the spring, summer, and fall months, the Lake temperature differs greatly from the air temperature. In the spring and summer, cool daytime temperatures persist due to wind shifts fi*om westerly to easterly directions. In autumn, the relatively warm water of the Lake prevents nighttime temperatures from falling as low as they do further inland. Summer temperatures exceed 90°F for six days on average. Freezing temperatures occur 147 days in a year on average, and temperatures are below OOF for 14 days of the winter on average (NEE, 2014b).

2.4.2 Rainfall Rainfall averages about 28 in./yr, with 55 percent falling in the months of May through September. The maximum rainfall of 6.17 in. over a 24-lu* period occurred in September 1931. Snowfall averages about 45 in./yr; the maximum snowfall occurred in January 1947 and was 15 in. over a 24-lu* period (NEE, 2014b).

2.4.3 Severe Weather Tornadoes are relatively rare in the region nmth of Sheboygan, Wisconsin along the Lake shoreline.

Tornadoes occur in Wisconsin but only one has been repmted causing major property damage and injury to people in this region. This tornado occurred in Green Bay in 1959, 30 mi northwest of the site. Tornadoes appear to advance from the west with most of the tracks from the southwest. Maximum occurrence during Page 16 of69

,.. ENERCON NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding NextEra Energy- PBNP March 6, 20 I 5 Excellence-Every project. Every day.

FPL-076-FHRPR-002, Revision 2 the year is in June, with 90 percent rep01ted in May through September. Extreme winds are not expected to exceed 108 mph more than once in I 00 yr (NEE, 20 14b).

2.4.4 Wind On an annual basis, the winds blow onshore (i.e., from the Lake towards the western shore) an average of 33.8 percent of the time. Onshore winds are defined as those which blow from the north through the south-southeast. Annually, winds blow offshore (i.e., from the westem shore towards the Lake) an average of 63.5 percent of the time. Calm conditions are experienced the remaining 2.7 percent of the time (i.e., 100 percent- 33.8 percent- 63.5 percent= 2.7 percent) (NEE, 2014b).

During the spring season, the predominant wind directions during the period of record were northeasterly and south-southwesterly. Wind speeds tended to be above 10 mph from all directions but east. A very predominant south-southwest wind direction was noted over the summer. Again, wind speeds averaged near I 0 mph, with the exception of southeasterly quadrant winds. The lowest average wind speed was 4.4 mph from the east (NEE, 20 I 4b ).

During autumn, average wind speeds from the west ranged from 10 to 14+ mph. There were relatively frequent occurrences of winds approximately parallel to the shoreline in both the n01therly and southerly directions. The lowest wind speeds were again from the east (NEE, 2014b).

The onset of cold weather is evidenced by the increased frequencies of winds from the n01thwesterly quadrant. The winter season is characterized by a preponderance of winds from the northwest quadrant, observed to occur over 60 percent of the time. During the winter months, no average wind speed from any direction was below I 0 mph. The average wind speed from the north-northeast was over 20 mph (NEE, 2014b).

On an annual basis, PBNP experiences predominating spikes of higher frequency winds from the west-northwest and the south-southwest. Average wind speeds are generally quite high from all directions from south-southeast clockwise through n01theast. All average values are in excess of 10 mph. Significantly lower frequencies and lower wind speeds are observed with easterly winds, partially due to the Lake' s influence on winds traveling against the normal gradient flow (NEE, 20 I 4b ).

2.4.5 Ice Storms Ice storms are infrequent in this region of Wisconsin. Only a single transmission line extending from Green Bay to Kewaunee to Sturgeon Bay has experienced outages due to ice storms since 1940. Since rebuilding that line with improved conductors in 1956, only one outage has occurred (NEE, 20 I 4b ).

2.4.6 General Lake Michigan Hydrology Lake Michigan and Lake Huron are considered at unity with respect to drainage and water level since the two lakes are connected via the Mackinac Straits. The drainage basin for the two lakes comprises 115,700 mi 2 and has an average annual rainfall of31 in. (NEE, 2014b).

Lake Michigan is the third largest of the Great Lakes. The Lake is 307 mi long from north to south and has an average east-to-west width of 70 mi. It has a maximum depth of 923 ft, an average depth of 325 ft, and covers an area of 22,400 mi 2

• The total volume of water in the Lake is approximately 1,400 mi 3

• In the Page 17 of69

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding ENERCON NextEra Energy- PBNP March 6, 2015 Excellence-Every project. Every day. FPL-076-FHRPR-002, Revision 2 general vicinity of PBNP, the 30-ft depth contour of the Lake is between 1.0 and 1.5 mi offshore, and the 60-ft depth contour is between 3.0 and 3.5 mi offshore (NEE, 2014b) .

The water level in the Lake depends primarily on the runoff from the surrounding drainage basin. The nominal water level in the Lake at the time of the original license submittal was +579.3 ft-NA VD88

(-2.0 ft-Plant Datum). A maximum water level was recorded in 1886 at +583.0 ft-NAVD88

(+ 1.7 ft-Plant Datum) and the minimum recorded to date occurred in 1964 at +576.5 ft-NA VD88

(-4.8 ft-Plant Datum) (NEE, 2014b). The temperature stratification and circulation patterns of water in the Lake have very distinct characteristics, as described in the following sections.

2.4.6.1 Thermal Stratification At the beginning of March, a warming trend starts in the Lake and, at the end of May, all of the water in the Lake has reached approximately 40°F, which is the temperature of maximum water density. Until the temperature reaches this point, the surface water is colder than the deeper water in the Lake; the colder surface water, which remains at approximately 34°F, is lighter than the 40°F deeper water. This layer of colder water circulates on the surface of the warmer deep water, reaching depths of 25 to 30 ft from the surface (NEE, 2014b).

When all of the water in the Lake reaches approximately 40°F, the thermocline layer disappears and complete mixing of all the water in the Lake occurs. However, when the ambient air temperature wmms up the surface water, a thermocline layer is formed again at depths of30 to 50ft from the surface. This occurs from May to July and, at this time, parts of the water in the Lake reach 65°F to 70°F. Consequently, the wmmer and lighter surface water circulates above the denser and relatively stagnant 40°F water at the bottom of the Lake. This condition continues until a cooling trend statts in September, reaching a peak about the last part of January, at which time the water in the Lake again reaches an overall temperature of 40°F. At this time, complete mixing of the waters in the Lake takes place until a colder and lighter layer of surface water starts to build up (NEE, 2014b).

2.4.6.2 Currents, Tides, and Littoral Drift Surface currents in the Lake are generated primarily by wind stress on the water surface. The Lake surface wind-driven currents have speeds averaging 1 to 2 percent of the wind speeds. Thus, an average wind speed of 15 mph over the Lake would generate an average surface current of about 0.15 to 0.3 mph (0.22 to 0.44 ft/s). Such currents may persist for several days after the wind has ceased. On large water surfaces, the wind-driven current is theoretically 45 degrees to the right of the wind vector (e.g., the current would be to the east for a northward wind) due to the rotation of the emth (i.e., the Coriolis effect). On the western side of the Lake, the current is largely parallel to the shore and more nearly 22 degrees to the right of the prevailing wind (e.g., the current would be to the north-northeast for a nmthward wind) . The predominant current direction near the western shore during the period of greatest stratification is in the northerly direction. However, temporary reversals ofthe general trend may take place (NEE, 2014b).

Tides on the Lake created by the gravitational attraction of the moon and sun are insignificant. The total tidal range of oscillation does not exceed 0.17 ft (2 in.) (NEE, 20 14b).

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NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding I

I ENERCON NextEra Energy- PBNP March 6, 2015 Excellence-Every project. Every day FPL-076-FHRPR-002, Revision 2 Waves are responsible for most of the littoral drift on the Lake. In this specific area, the predominant drift appears to be to the n01th. Under unfavorable conditions, littoral drift may have a pronounced effect on the advance or retreat of cettain shorelines. At PBNP, the beach is narrow, ranging from 20 to 50 ft. The shoreline recession rates range from 2.5 to 5 ft/yr. Special protection is provided to control further recession of the shoreline at PBNP (NEE, 20 14b).

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NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding ENERCON NextEra Energy- PBNP March 6, 2015 Excellence- Every project. Every day FPL-076-FHRPR-002, Revision 2 3.0 CURRENT LICENSE BASIS FOR FLOODING HAZARDS This section describes the primary flooding mechanisms and their associated water surface elevations (WSELs) and effects at PBNP based on information contained in UFSAR Chapters 2 and 5 and AppendixA.7 (NEE, 2010; NEE, 2014b; NEE, 2014c). This section also summarizes PBNP's current flood protection features and procedures.

3.1 CLB- Maximum Precipitation Flood The CLB precipitation event for PBNP is the combination of the 6-hr rainfall with a 50-yr recurrence frequency and the water content of snow in late March with a 50-yr recurrence frequency. This combined volume of water is equivalent to 4.90 in. over the 6-hr duration. The topography of the site results in adequate natural drainage to remove this amount of water and limit ponding depth to prevent adversely affecting safety-related equipment (NEE, 20 14b). Maximum WSELs at PBNP points of interest (POls) are shown in Table 3.1.

3.2 CLB- Riverine (Streams and Rivers) Flooding No significant streams flow by or near the site. Two small creeks drain to the north and south. One creek discharges into the Lake about 1,500 ft nmth of the northern corner of PBNP property and the other near the center of PBNP property. Therefore, a PMF runoff analysis was not performed for the CLB (NEE, 2014b).

3.3 CLB- Dam Breaches and Failure Flooding There are no dams, area reservoirs, plant cooling water canals, or plant cooling water reservoirs planned for or located upstream from the site. Cooling water is supplied by the Lake as the primary source and UHS. In view of the topography and characteristics ofthe local streams, it seems unlikely that reservoirs of any substantial size will be built in the future. Dam failures were not considered a meaningful hazard at PBNP (NEE, 2014b).

3.4 CLB- Lake Michigan Flooding The CLB Lake flood level, +589.72 ft-NA VD88 (+8.42 ft-Plant Datum), is a combination of the historical maximum Lake elevation of +583.0 ft-NA VD88 (+1.7 ft-Plant Datum) coincident with +0.17 ft wind setup and +6.55 ft wave runup on a vertical surface. Bank protection is based on riprapping the slope adjacent to the beach. The wave runup will encounter this slope or the vertical faces formed by the front of the intake structure or adjacent sheet piling walls (NEE, 2014b).

3.4.1 Storm Surge Background The water level of the Lake is a function of a number of factors : the amount of snowmelt and runoff, long-term variation in the Lake level due to variations in water supply, storm surge, seiche, and wind setup. The frequency that the Lake rises to a patticular level is a function of the frequency ofthe individual independent contributing primary causes.

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NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding ENERCON NextEra Energy- PBNP March 6, 2015 Excellence-Every proj ect. Every day FPL-076-FHRPR-002, Revision 2 At any given time, the Lake level is a function of the still water level (SWL) plus wind-generated waves.

Breaking waves also produce runup onshore. Therefore, the resultant final water elevation is equal to the level of the Lake due to a storm surge, seiche, or other flooding mechanism plus the amount of run up due to breaking waves near the shore.

The maximum water surface level at PBNP is defined as the SWL produced by storm surge, seiche, wind setup, and wave run up at the shore.

Flooding on the Lake shoreline can occur due to storm surge produced by moving squall lines, seiche, and wave setup. In addition to these effects, wave run up could result in somewhat higher elevations at the Lake shore due to waves breaking on or near sloped or vertical surfaces.

3.4.2 Astronomical Tides Tides on the Lake created by the attraction of the moon and sun are quite small; the total range of oscillation does not exceed 0.17 ft (2 in.). The CLB does not use a tidal component in determining the maximum Lake flooding (NEE, 2014b).

3.4.3 Maximum Historical Lake Michigan Water Level The maximum Lake level of +582.0 ft-NA VD88 (+ 1.7 ft-Plant Datum) was recorded in 1886. This maximum Lake level was used to determine maximum Lake flooding (NEE, 2014b).

3.4.4 Probable Maximum Windstorm A sustained easterly wind velocity of 40 mph over a fetch length of70 mi and average depth of 465ft was used to determine the CLB wind setup component coincident with the maximum wave runup (Section 3 .4.6). The maximum storm surge was calculated based on a squall line with a pressure rise of 8 mbar (0.236 in. Hg) traveling at 65 knots (NEE, 2014b).

3.4.5 Wave Action The 500-yr frequency maximum, deep water wave height in the Lake was defined as 23.5 ft for a full-yr period and 18.0 ft for the ice-free period. Due to the extremely flat slopes of the beach near PBNP (1: 100 in the first 1,000 ft into the Lake and 1:200 for the next 4,000 ft into the Lake 2), such large waves would break far offshore and do not need to be considered for runup at PBNP. In this case, only waves oflesser height actually need to be evaluated for the runup on the beach (NEE, 2014b).

3.4.6 Wave Runup Two methods of wave runup analysis were followed in the CLB. In the first case, the 500-yr maximum full-yr, deep water wave was treated as impinging upon a breakwater with very flat slopes, with the toe of 2

Slopes are rep01ted as vertical (V) to horizontal (H), V:H.

Page 21 of69

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding NextEra Energy- PBNP ENERCON March 6, 2015 Excellence-Every project. Every day FPL-076-FHRPR-002, Revision 2 the slope located in a water depth of 12ft. The computed vertical height above normal water level for this case was 1.4 ft (NEE, 20 14b).

In the second case, an estimate of the probable maximum secondary wave, a wave height of 4.68 ft, was determined from the average depth (6 ft) prevailing after the larger deep water wave has broken and reformed (S&L, 1967). The runup on the beach above the water level was computed for a wave period of 8 s as 7.72 ft on a 1:1.5 smooth slope, 3 5.38 ft on a 1:1.5 riprap slope, and 6.55 ft on a vertical structure (Table 3.2) (NEE, 2014b).

Prolonged winds of high velocity tend to form a wind tide setup. Accordingly, a conservative wind setup of 0.17 ft was used, based on a sustained easterly wind velocity of 40 mph over a fetch length of 70 mi and average depth of 465 ft . Thus, the maximum expected run up on a ve1tical structure would be 6. 72 ft above the antecedent water level (i.e., 6.55 ft + 0.17 ft = 6.72 ft) (NEE, 2014b).

The maximum recorded water level in the Lake was +583.0 ft-NA VD88 (+1.7 ft-Piant Datum). Assuming conservatively that the maximum wave runup occurs simultaneously with the maximum level, the runup would reach to +589.72 ft-NA VD88 (+8.42 ft-Piant Datum) on a vertical structure (i.e.,

+580 ft-NA VD88 + 6.72 ft = 586.72 ft-NA VD88) (NEE, 2014b).

3.4.7 Maximum Storm Surge The CLB storm surge was calculated to be 4.14 ft due to the passage of a squall line with a pressure increase of8 mbar (0.236 in. Hg) and a simultaneous speed of movement of65 knots with a shoaling factor of3.5.

Adding this 4.14 ft of storm surge to the maximum recorded Lake level of +583.0 ft-NA VD88

(+ 1.7 ft-Piant Datum) results in an elevation of +587.14 ft-NA VD88 (+5.84 ft-Piant Datum), which is considerably lower than the TB grade floor elevation of +589.3 ft-NA VD88 (+8 .0 ft-Plant Datum) or the CWPH operating floor elevation of+588.3 ft-NAVD88 (+7.0 ft-Piant Datum) (NEE, 2014b).

The value of 4.14 ft was developed using Platzman's contours of amplitude for pressure. There are no contours for the Lake in the area near PBNP, so the reflected surge values for Waukegan, Illinois were used for a squall line moving east (i.e., 90 degrees) with a speed of 65 knots (75 mph). The resulting pressure rise was 0.05 ft. Using 8 mbar (0.236 in. Hg) and applying a 3.5 shoaling factor, the maximum surge due to pressure is 0.236 inHg 0.05 ft X 0.0 in Hg X 3.5 = 4.14 ft.

1 This amplitude was adjusted fmther based upon the wind velocity. For velocities greater than or equal to 70 knots (81 mph), a surge increase of 1 ft over the computed value is applied, so that the maximum storm surge becomes 5.14 ft (i.e., 4.14 ft + I ft = 5.14 ft), which is bounded by the maximum wave runup on a vertical structure. If the maximum surge occurs coincident with the maximum historical Lake level, the 3

Slopes are repmted as vertical (V) to horizontal (H), V:H.

Page 22 of 69

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding NextEra Energy- PBNP ENERCON March 6, 2015 Excellence- Every project. Every day FPL-076-FHRPR-002, Revision 2 maximum storm surge elevation will be +588.14 ft-NA VD88 (+6.84 ft-Piant Datum) (i.e.,

+583.0 ft-NA VD88 + 5.14 ft = +588 .14 ft-NA VD88), which is still below the TB floor level (NEE, 2014b).

3.4.8 Seiche Seiches are caused by a frontal squall line defining an abrupt change in atmospheric pressure in the range of 3.4 mbar (0.1 in. Hg) moving across the Lake at a high velocity. An average of20 seiches/yr occur near Chicago, but the rise in Lake level is often insignificant (NEE, 20 14b).

The open shoreline at PBNP will not be subject to reflection and should not produce any amplification of the seiche height. It appears logical to consider that the rise in water level due to the seiche would be a maximum of 1 to 2 ft. Historical records show that the peak rise in water level associated with a seiche can be achieved very quickly. The record seiche in Chicago on June 26, 1954lasted about 0.5 hr. The historical records did not reveal the coincident occurrence of a major seiche with a major high wave condition. Winds of high velocity have been recorded before or after seiches for relatively sh01t periods of time, but there is no basis to superimpose the conditions of the maximum wave upon the maximum seiche. Thus, a maximum seiche is not combined with the maximum Lake level, maximum wind setup and maximum wave runup in the combined effects analysis (NEE, 2014b).

3.5 CLB- Tsunami Flooding A tsunami was not considered a meaningful hazard to PBNP (NEE, 20 14b).

3.6 CLB- Ice-Induced Flooding No specific ice flooding design criteria are proposed for safety-related facilities since the facilities are located at an elevation which makes them invulnerable to any local ice activity. Local flooding due to ice formation is considerably below maximum surge conditions (NEE, 2014b) .

Ice flooding and associated effects were not considered meaningful hazards at PBNP. The U.S. Coast Guard rep01ted pile up of ice in the form of frozen spray and ice floes to a height of 30 to 40ft at the shore and extending about 100ft into the Lake. These observations were made at Rawley Point Lighthouse 5 mi south of the site. Similar conditions have been experienced at many power stations along the Lake (NEE, 2014b).

The primary reason for the buildup seems to be the formation of ice which is driven out to deep water by offshore winds and collected until a change in wind drives these ice floes towards the shore. As they approach shallow water, they ground and the offshore floes are driven up and over the grounded floes. The peak point in height of this buildup does not occur at the shoreline on extremely flat beaches, but some distance offshore. This action has given rise to reports of "ice shoves" which have damaged fish shanties on a beach or light wharf structures projecting into the water (NEE, 2014b).

Beach structures for power stations represent a massive installation and the history of such structures has shown no major damage from ice shoves even where these have been located next to the shoreline on shallow beaches. The outer wall of the intake fore bay, the only structure on the beach, is designed with Page 23 of69

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding ENERCON NextEra Energy- PBNP March 6, 2015 Excellence-Every project. Every day FPL-076-FHRPR-002, Revision 2 3-ft-thick reinforced concrete. This is considered adequate to withstand any pressure from the ice. The water intake is located 1,750 ft offshore in a water depth of 18ft, measured from the lowest recorded Lake level of +576.5 ft-NA VD88 (-4.8 ft-Plant Datum). Water is drawn from the intake crib through two 14-ft-diameter pipes buried below the Lake bed and will not be affected by ice. The cooling water is discharged through two flumes consisting of well-braced steel sheet piling driven 40ft into the Lake bed and protected by riprap. This is considered adequate to withstand any pressure from the ice. Other structures are located approximately 190 ft .from the beach line and are fUJther protected by the low bluff along the shoreline (NEE, 2014b).

3. 7 CLB- Channel Migration or Diversion Flooding No significant streams flow by or near the site. Channel migrations or diversions of the small creeks were not considered meaningful hazards at PBNP (NEE, 2014b).

3.8 CLB- Combined Events Flooding The combined CLB precipitation-snowmelt event is discussed in Section 3.1. The resulting maximum WSELs are listed in Table 3.1. The maximum storm surge was considered coincident with the maximum historical Lake level. The maximum flood level was the maximum wave runup on a vertical structure occurring during the maximum historical Lake level with wind setup from a sustained 40 mph easterly wind. No other combination events were considered in the CLB (NEE, 2014b).

3.9 CLB - Flooding Protection The extemal CLB protection at PBNP provides for the mitigation of CLB floods to prevent ingress of water from occurring in rooms with SSCs impmtant to safety with the exception of possible water intrusion to the service and fire water pump rooms in the CWPH during a wave runup event. The CLB does not specify which plant configurations are considered (NEE, 20 14b).

The CLB maximum probable wave runup from the Lake is +589.72 ft-NA VD88 (+8.42 ft-Plant Datum).

The CLB requires the installation of concrete barriers and sandbags to provide a flooding barrier at the CWPH that would protect equipment in the CWPH and TB from the flood waters up to +590.3 ft-NA VD88

(+9.0 ft-Piant Datum) (NEE, 2014b).

The following strategies are used to protect the CWPH from wave runup (NEE, 2014c):

• Monitoring of Lake level;

• Combining shore riprap with intake structure to reduce the total wave run up height;

• Constructing temporary barriers (i.e., concrete blocks and sandbags on the outside and sandbags on the inside) at CWPH rollup Door 336 and Door 340 (shown on Figure 4.5);

• Crediting sufficient frames at tight-fitting CWPH personnel Door 338 and Door 339 (shown on Figure 4.5) to protect against wave runup forces; and Page 24 of69

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding F.:dENERCON NextEra Energy- PBNP March 6, 2015 Excellence-Every project. Every day. FPL-076-FHRPR-002, Revision 2

• Placing sandbags inside of tight-fitting CWPH personnel Door 338 and Door 339 (shown on Figure 4.5) to protect from water ingress.

Futiher, the CWPH service water pump motors, at +590.63 ft-NA VD88 (+9.33 ft-Plant Datum), are the lowest safety-related component in the CWPH. All flooding-susceptible, safety-related equipment in the CWPH is mounted above the external CLB flood level and would not be subject to flooding, irrespective of other protection features. The augmented quality diesel fire pump control panel is mounted at

+589.675 ft-NA VD88 (+8.375 ft-Plant Datum), which exceeds the calculated levels inside the CWPH from the CLB external flood when crediting the floor flood relief dampers (NEE, 20 14c).

The fore bay pmiion of the intake structure extends 65 ft from the shoreline back to the CWPH and has vetiical walls extending to elevation +596.7 ft-NA VD88 (+ 15.4 ft-Plant Datum) parallel to the shoreline (i.e., east side of the CWPH) and to elevation +593.3 ft-NA VD88 (+ 12.0 ft-Plant Datum) perpendicular to the shoreline (i.e., nmih and south sides of the CWPH). These walls protect the CWPH pmiion of the intake structure from the runup due to a wave impinging on a vertical structure. The bank adjacent to the intake structure has riprap placed on a I :2 slope, and the runup pmiion will be somewhat less than the maximum of +589.72 ft-NA VD88 (+8.42 ft-Plant Datum) indicated above. If the waves break over the bank around the CWPH, storm drains are provided outside each of the doors of the CWPH and there are no openings in the walls, other than tight-fitting doors that have a bottom elevation less than +590.3 ft-NA VD88

(+9.0 ft-Plant Datum). In addition, storm drains are provided outside of the CWPH doors (NEE, 2014b; NEE, 2014c).

The following strategies are used to protect the TB, Control Building, and PAB (which are separate structures approximately 100ft inland from the CWPH) from wave runup (NEE, 2014c):

• Monitoring of Lake level.

• Combining shore riprap with intake structure to reduce the total wave runup height.

• Crediting the distance from the Lake to the TB to reduce the total wave runup height.

• Protecting from wave impact forces with the concrete and steel missile barriers for the diesel air intake louvers.

• Crediting sufficient frames at TB persmmel Door 2 and Door 11 (shown on Figure 4.5) to protect against wave runup forces.

• Sealing covers on Manhole Z-66A and Manhole Z-67 A to block conveyance into the Control Building.

• Operator-directed action to shut down operating reactors and secure secondary systems (i.e.,

cooling water, condensate, and feedwater) prior to the Lake reaching a critical level.

• Operator-directed action to detect and mitigate a leak from other non-Category I (seismic) sources.

• Procedurally installing temporary barriers at +589.3 ft-NA VD88 (+8.0 ft-Plant Datum) exterior doors and openings of the TB prior to the Lake reaching a critical level. These barriers and strategies inc! ude:

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NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding ENERCON NextEra Energy- PBNP March 6, 2015 Excellence-Every project. Every day.

FPL-076-FHRPR-002, Revision 2 Station a dedicated flood watch any time the extemal flooding barriers are in place; Open Auxiliary Feedwater Tunnel Door 6 and Door 19 prior to installation of turbine hall exterior barriers to protect against non-Category I (seismic) component rupture; Install steel stop logs outside ofTB roll up Door 4 and Door 13 (shown on Figure 4.5), TB Flood Dampers 1 and 2Z-329, and Maintenance Shop rollup Door 76 (shown on Figure 4.5) to protect from wave forces; Procedurally install Presray devices inside TB access Door 2 and Door 11 (shown on Figure 4.5) to limit water ingress; Place sandbags inside TB rollup doors, TB flood dampers, the Maintenance Shop roll up door, and Maintenance Shop access Door I (shown on Figure 4.5) to limit flood water ingress into the structures; and Install stackable, water-resistant stop logs on the inside of the air intake louvers to Rooms G-01 and G-02 to limit water ingress.

The installation of turbine hall extemal flooding barriers requires both units to be in Operation Mode 5, which is outside the mode of applicability for auxiliary feedwater operability. The Diesel Generator G-03/04 Building slab is at +609.3 ft-NA VD88 (+28.0 ft-Plant Datum), well exceeding the

+590.3 ft-NA VD88 (+9.0 ft-Plant Datum) CLB flood level.

3.10 CLB- Low Water Effects The lowest recorded Lake water level was +576.5 ft-NA VD88 (-4.8 ft-Plant Datum). The intake structure is 18ft below this level and sufficient water is still available to meet PBNP requirements. Low water levels related to surges, seiches, or tsunamis were not evaluated in the CLB (NEE, 2014b).

3.11 CLB- Hydrostatic, Hydrodynamic, Sediment, and Debris Loading Hydrostatic, hydrodynamic, sediment, and debris loading on permanent PBNP structures were not evaluated in the CLB. The wave barriers to be deployed during elevated Lake levels were designed to prevent sliding or overturning from hydrostatic and hydrodynamic forces associated with CLB maximum wave runup elevations (NEE, 2014b).

3.12 CLB- Waterborne Projectiles Waterborne projectiles were not considered in the CLB; however, tornado missiles were analyzed. The following tornado missiles were considered (NEE, 201 0; Bechtel, 1970):

I. A wood plank measuring 4 in. x 12 in. x 12 ft, weighing 200 lbs, traveling at a velocity of 440 ft/s (300 mph) and

2. An automobile with a cross-sectional area of20 ft 2, weighing 4,000 lbs, traveling at a velocity of74 ft/s (50 mph).

Page 26 of69

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding NextEra Energy- PBNP ENERCON March 6, 2015 Excellence-Every project. Every day. FPL-076-FHRPR-002, Revision 2 All Class I structures were designed to withstand tornado missiles. None of the analyzed missiles would penetrate the containment (NEE, 2010). From the above tornado missiles, the maximum design impact pressure is for the wood plank: 149,068 psf.

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NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding ENERCON NextEra Energy- PBNP March 6, 2015 Excellence-Every project. Every day.

FPL-076-FHRPR-002, Revision 2 4.0 FLOODING HAZARDS REEVALUATION The following sections discuss the flood-causing mechanisms, associated WSELs and related effects that were considered in the PBNP FHR. Selected PBNP site features are shown on Figure 4.1 for reference throughout Section 4.0.

4.1 Local Intense Precipitation LIP is a measure of high intensity, shmt duration precipitation at a given location. Generally, for smaller basin areas (up to 10 me), shorter storm durations produce the most critical runoff scenario. High intensity rainfall in a small area has a shmt concentration time and, therefore, a high intensity runoff. Thus, the shmter storm occurring over a small watershed will result in higher flow rates and depths at PBNP. As defined in NUREG/CR-7046 (NRC, 2011), the LIP event will be the 1-lu*, l-mi 2 probable maximum precipitation (PMP) at PBNP.

The sections below describe the LIP evaluation process for PBNP:

• LIP intensity and temporal distribution development (Section 4.1.1 );

• Runoff and routing model overview (Section 4.1.2);

• Surface topography generation (Section 4.1.3);

• Impediments and obstructions to flow (Section 4.1.4);

• Selection of surface infiltration and roughness characteristics (Section 4.1.5);

• Incorporation of yard drain network (Section 4.1.6);

• Runoff model scenarios evaluated (Section 4.1.7);

• Runoff transformation, translation, and conveyance processes (Section 4.1.8); and

• Model results (maximum water depths and flow velocities) (Section 4.1 .9).

4.1.1 Local Intense Precipitation Intensity and Distribution A site-specific LIP evaluation was used for PBNP, following a recommended storm-based approach (ANS/ANSI, 1992; WMO, 2009; NRC, 2011). The storm-based approach is detailed in Hydrometeorological Report (HMR) 33 (Riedel et al., 1956) and HMR 51 (Schreiner and Riedel, 1978).

The storm-based approach uses historical, regional rainfall data, which are maximized and transpositioned to occur at PBNP. The initial step in the storm-based approach was to identify a set of storms which represent extreme precipitation events, such that high rainfall totals occurred over short durations and small area sizes. Storm types included thunderstorms and intense rainfall associated with Mesoscale Convective Complexes. This procedure is similar to what is described in HMR 52, Section 6 (Hansen et al., 1982). A total of21 historical events from a similar meteorological and topographic setting were selected for detailed evaluation of LIP totals at PBNP. Thi1teen of these storms were previously analyzed in HMR 33 and HMR 51 by the National Weather Service (NWS) and U.S. Army Corps of Engineers (USACE).

Each historical storm event was modified by a transpositioning algorithm. The adjustment factor is a combination of the atmospheric moisture and terrain influences (e.g., elevation, temperature) on rainfall, Page 28 of69

,.. ENERCON Excellence- Every proj ect. Every day.

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding NextEra Energy- PBNP March 6, 2015 FPL-076-FHRPR-002, Revision 2 maximized and transpositioned to PBNP. The result is the rainfall total volume to be expected at PBNP if all contributing factors were maximized and occurred simultaneously. After adjustments were applied, the maximized and transpositioned May 1943 Mounds, Oklahoma storm event had the highest 1-hr rainfall; several other storms provided slightly smaller total rainfall amounts. The 1-hr, 1-mF total precipitation depth is 12.8 in.

To fully develop the temporal rainfall distributions (i.e., hyetographs), the hourly rainfall total was disaggregated into subhourly increments of 5, 15, and 30 min. A lack of sub hourly PMP-type storm data prevented an updated evaluation from being completed; therefore, the ratios derived in HMR 52 Figures 36 and 38 (Hansen et al., 1982) were applied to PBNP for the subhourly precipitation intensities. The site-specific 5-min, 15-min, 30-min, and 60-min LIP intensities are shown in Table 4.1. The peak LIP rainfall intensity is 4.4 in. over 5 min.

The total precipitation depths were applied to four hyetographs : (I) first qua1tile, (2) second qumtile, (3) third qumtile, and (4) fourth quartile (Figure 4.2). Each hyetograph is distinct based on the time to peak rainfall intensity. For example, the first qumtile hyetograph has the most intense precipitation at the beginning of the event, whereas the fourth qumtile hyetograph has the most intense precipitation at the end of the event. All four hyetographs have the same total rainfall (i.e., 12.8 in. over 1 hr). The hyetographs were used to determine the sensitivity of the temporal rainfall distribution and bounding maximum flow depths in Section 4.1.9.

4.1.2 Runoff and Routing Model Overview FL0-2D PRO (Build 14.08.09) software by FL0-2D Software, Inc. (FL0-2D, 2014) was used to evaluate the LIP runoff event at PBNP. FL0-2D PRO has a number of components to simulate street flow, building and obstructions, sediment transpmt, spatially variable rainfall and infiltration, floodways, and other flooding effects. Predicted flow depths and velocities between the grid elements are average hydraulic flow conditions computed for small time steps (on the order of seconds). Typical applications ofFL0-2D PRO have grid element resolution that ranges from 5 to 500 ft. The number of grid elements is theoretically unlimited but is confined practically by processing capability. The output files provide time-dependent WSELs, flow velocities, and other hydraulic parameters at each computational element (FL0-2D, 2014).

4.1.3 Surface Topography Generation A digital terrain model (DTM), derived primarily from a recent site topographic survey (NEE, 2014a),

shown on Figure 4.3, was impmted into FL0-2D PRO and a 5-ft resolution grid domain was developed because the typical flow pathways on the site are of that width or wider. The boundary elements were prescribed as outflow points with no hydrograph, allowing runoff to freely leave the domain.

4.1.4 Obstructions and Flow Impediments Obstructions and surface flow impediments include permanent buildings, temporary structures (e.g.,

storage containers), (wave) barriers, and topographic features . Buildings, temporary structures and barriers were entered explicitly into the DTM (Figure 4.3).

Runoff from the permanent building and temporary structure areas is a hydrologic feature of the model.

Permanent building roofs were incorporated as flat surfaces (Figure 4.3). This approach prevents rooftop Page 29 of69

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding ENERCON NextEra Energy- PBNP March 6, 2015 Exce llence-Every proj ect. Every day.

FPL-076-FHRPR-002, Revision 2 water storage and assumes roof drains are nonfunctional; runoff from building rooftops is routed directly to the ground adjacent to the building. The model layout captures building heights relative to each other to preserve anticipated runoff routing. FU!iher, the building heights used in the DTM were set higher than expected maximum runoff flow depths to prevent flow into buildings or roofs. Temporary structures were modeled as flat, raised surfaces with heights typical of storage containers. All rainfall in these areas was routed to adjacent ground cells.

The elevations of the model cells chosen to represent POls on the east side of the TB were set at

+589.3 ft-NA VD88 (+8.0 ft-Plant Datum) to accurately determine the flood elevations at TB east doors.

To ensure model stability, all elevations directly east of the TB were adjusted to +589.3 ft-NA VD88

(+8.0 ft-Plant Datum) (Figure 4.3).

4.1.5 Surface Infiltration and Roughness Characteristics Because of the large percentage of impervious, paved area across the model domain, the relatively shmi duration of the storm (i.e., 1 hr), and the extreme rainfall total (i.e., 12.8 in.), the antecedent conditions are assumed to be full ground saturation. Accordingly, zero infiltration was credited in the runoff model. This assumption is consistent with NUREG/CR-7046 (NRC, 2011).

Manning's equation, based on uniform, fully developed turbulent runoff flow, was used to determine hydraulic roughness. The assignment of overland flow roughness accounts for vegetation and surface irregularities. The following Manning's rouglmess coefficients (dimensionless) were selected:

• 0.02 for asphalt or concrete;

• 0.20 for open ground with debris; and

• 0.40 for shrubs and forest litter and/or pasture.

The spatial distribution of the designated Manning' s roughness coefficients at PBNP is provided on Figure 4.4.

4.1.6 Storm Drain Network The yard drain system was considered nonfunctioning (i.e., 100 percent blocked) in the runoff results presented in Section 4.1.9.

4.1. 7 Runoff Model Scenarios Two LIP scenarios were evaluated:

• Scenario A, which considered the temporary laydown areas (Figure 4.5) completely occupied with equipment/containers.

• Scenario B, which had the same occupied temporary laydown areas as Scenario A in addition to the temporary wave barriers installed adjacent to the CWPH (Section 3.9 contains details regarding temporary wave barrier deployment and positioning). In the FL0-2D model, the cells adjacent to the CWPH where the wave barriers would be installed were manually adjusted to be 3.5 ft higher for Scenario B.

Page 30 of69

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding ENERCON NextEra Energy - PBNP March 6, 2015 Excellence- Every p roject. Every day FPL-076-FHRPR-002, Revision 2 Assuming the temporary laydown areas are completely occupied removes the storage area and/or flow paths available if equipment, containers or barriers are not present there. Thus, Scenario A and Scenario B should be considered bounding if temporary structures are removed from the areas shown on Figure 4.5. Each scenario was evaluated for the four hyetographs detailed in Section 4.1. 1, such that eight total model simulations were completed (i.e., two scenarios times four hyetographs equals eight model simulations).

Thirty-three doors were identified as POls for the LIP evaluation (Figure 4.5). Time-dependent flow depths, velocity time series, maximum flow depths, and maximum WSELs were reported at each POI. The simulations were allowed to run for 10 hr to allow for flood recession and adequately capture the total duration of the LIP flood event at each POI.

4.1.8 Runoff Model Processes and Successful Application Criteria FL0-2D PRO is a simple, two-dimensional, physical process model based on a volume conservation model.

The general governing equations are the continuity equation (i.e., conservation of mass/volume) and dynamic wave momentum equation (i.e., conservation of motion). These equations are solved to route rainfall-runoff and flood hydrographs over unconfined surfaces or in channels (FL0-2D, 2013).

A set of pmtial differential equations (St. Venant or shallow water equations, which are derived from the conservation of mass and motion criteria described above) is solved using the second-order Newton-Raphson tangent finite difference method. The computational domain in the FL0-2D PRO model is discretized into uniform, square grid elements. The discharge is computed in eight different directions across the grid element boundary (FL0-2D, 2013).

The full dynamic wave equation is a second-order, nonlinear, hyperbolic differential equation. To solve the equation for flow velocity at a grid element boundary, the flow velocity is calculated initially with the diffusive wave equation using the average water surface slope (i.e., bed slope plus pressure head gradient).

This velocity is then used as a first estimate in the second-order Newton-Raphson tangent method to determine the roots of the full dynamic equation. Then, Manning's equation is applied to compute the friction slope. If the solution fails to converge after three iterations, the algorithm defaults to the diffusive wave solution (FL0-2D, 2013).

Successful FL0-2D PRO model applications meet the following criteria:

• A small volume conservation error;

• No invalid areas of inundation introduced by one-dimensional channel elements; and

• No numerical surging resulting from mismatched flow area, slope, and roughness.

The maximum mass balance error in the runs (volume conservation error) was less than 0.001 percent (6.1 x 10*4 ac-ft), which is within the acceptable continuity error range (FL0-2D, 2013). Fmther, since the PBNP runoff model does not contain one-dimensional channel elements, there are no invalid areas of inundation.

The maximum velocity and numerical surging are related to the area of inundation. Numerical surging is the result of a mismatch between flow areas, slope, and roughness and can cause an over-steepening of the flood wave. To avoid numerical surging, the FL0-2D PRO model is subject to the Courant-Friedrichs-Page 31 of69

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding ENERCON NextEra Energy- PBNP March 6, 2015 Excellence-Every project. Every day. FPL-076-FHRPR-002, Revision 2 Lewy (CFL) condition used for the explicit solution scheme. The CFL condition states that the numerical solution remains stable only for Courant numbers (C) less than or equal to 1.0, defined as:

_ IVI+c C - l!.x Equation 4.1 M

where:

C =Courant number (dimensionless);

V =flow velocity (ft/s);

c =wave celerity (ft/s);

Llx =grid size resolution (ft); and Lit =time step (s).

To preserve stability, a conservative maximum Courant number (Cnax) less than or equal to 0.6 is imposed on the floodplain cell solution. This setting forces a reduction in time step if the stability threshold is approached as the solution progresses. A 5-ft grid resolution (Llx) is used to describe the surface topography of PBNP (Section 4.1.3). The default time step (Lit) of FL0-2D PRO is 30 s (FL0-2D, 20 13). Violation of the CFL condition was a consideration for the PBNP FL0-2D PRO model. FL0-2D PRO internally modified the time step until the specified CFL condition (i.e., Equation 4.1) was met. The typical minimum time step during peak LIP runoff flows at PBNP was on the order of0.01 s.

A minimum depth of flow of0.01 ft was imposed across the computational elements to prevent small flow oscillations from unnecessarily increasing the computational time. As the PBNP LIP runoff model is primarily concerned with maximum flooding and therefore water depths greater than 0.01 ft, this modification was assumed to be valid.

A nonzero storage volume must be applied to each grid cell for FL0-2D PRO to compute a solution. A storage depth of0.01 ft was applied to all grid cells since 0.01 ft is small in comparison to the LIP rainfall of 12.8 in. over 1 hr. This mtificial abstraction was assumed to have a negligible effect on the final results.

Artificial viscosity and change of flow depth tolerance were not required to preserve numerical stability of the solution. Coefficients for these terms were set to zero.

The CFL condition was satisfied for all model simulations. Thus, all criteria were met for a successful FL0-2D PRO model application.

4.1.9 Model Results The direct drainage area for PBNP is mapped on Figure 4.6. The drainage area includes the power block and extends north and west, extending across the northern portion of the switchyard. In general, runoff is directed west to east, around the PAB and TB. Surface runoff ultimately flows around the notth and south sides of the CWPH and exits the site to the Lake.

Two scenarios were considered (A and B), as defined in Section 4.1.7. The maximum flow depths and peak WSELs (in ft-Plant Datum and ft-NA VD88) for Scenario A and Scenario B at the 33 POls are listed in Table 4.2. Maximum flow depths are mapped for the PBNP power block on Figure 4.7 (Scenario A) and Figure 4.8 (Scenario B). Since the CWPH wave barriers pattially obstruct the flood relief pathways to the Lake, the runoff takes longer to exit the site during Scenario B. Accordingly, the maximum ponded levels Page 32 of69

NTTF Recommendation 2.I (Hazard Reevaluations): Flooding ENERCON NextEra Energy- PBNP March 6, 20I5 Excellence- Every project. Every day FPL-076-FHRPR-002, Revision 2 at the east TB and CWPH are higher in Scenario B than Scenario A. Scenario A and Scenario B produced similar maximum flood levels for POls at other locations. In general, the third qumtile and fomth qumtile hyetographs resulted in the maximum flood elevations, with maximum flow depths up to +2.1 ft at the CWPH for the fomth qumtile LIP event. A flow depth time series at TB Door 13 (see Figure 4.5 for location) for LIP Scenario B, typical of the TB and CWPH POls, is shown on Figure 4.9. The peak flow depth (i.e., 2.6 ft) is reached near the end of the I -hr event; the flow depth drops to less than I in. after an additional 2 hr (i.e., approximately 3 hr from the beginning of the LIP event).

4.2 Riverine Flooding PBNP is located on Lake Michigan and there are no major streams or rivers that contribute to flooding at the site. The only contributing runoff drainage area to PBNP is less than 1 mF; there are no adjacent surface water run-ons to the site. Thus, the riverine PMF is not applicable to PBNP.

4.3 Dam Breaches and Failures There are no dams located upstream or downstream of PBNP; therefore, there is no potential for dam breach-related flooding.

4.4 Probable Maximum Storm Surge A computer-based numerical model is used to estimate the probable maximum storm surge (PMSS) and associated wave effects from a suite of theoretical design storms. The numerical model is developed using the Delft3D Version 4.00.01 software package (Deltares, 2011). The synthetic probable maximum windstorm (PMWS) events are developed in accordance with applicable guidance documents (e.g.,

ANSI/ANS, I 992; NRC, 2011; NRC, 20 13a), which provide the basis for the site-specific storm methodology.

The sections below describe the PMSS evaluation process at PBNP:

• Description of the Delft3D modeling system and processes (Sections 4.4.1, Section 4.4.2 and Section 4.4.3);

• Development of the numerical surge model and physical parameters (Section 4.4.4);

• Selection of numerical parameters (Section 4.4.5);

• Determination of antecedent Lake levels (Section 4.4.6);

• Development of design synoptic PMWS events suite (Section 4.4.7);

• Calibration and validation of the numerical surge model (Section 4.4.8);

• Description ofPMSS methodology (Section 4.4.9); and

• PMSS and wave run up maximum WSEL results (Section 4.4.10).

4.4.1 Methodology Overview The PMSS is simulated with a two-dimensional, depth-averaged unsteady flow characterizing storm surge and lake currents with Delft3D-FLOW Version 4.00.04.757 (Deltares, 2011). The Navier-Stokes equations for incompressible flow are solved under the shallow water and Boussinesq assumptions. These equations Page 33 of69

,.. ENERCON Excellence- Every project. Every doy NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding NextEra Energy - PBNP March 6, 2015 FPL-076-FHRPR-002, Revision 2 are reduced to an implicit finite difference approximation through the Crank-Nicholson numerical scheme (Deltares, 2014a). The simplifications incorporated into Delft3D-FLOW allow for shoaling within shallow water. A detailed review ofDelft3D benchmarking test cases is presented in Walstra and Koster (2006).

Wave transformation in Delft3D-WAVE is performed using Simulating WAves Nearshore (SWAN).

SWAN is a spectral wave model that evaluates the refracted wave height and wave angle based on a spectrum of waves using linear wave theory (Booij et al., 1999; Deltares, 2014b). The SWAN model accounts for (refractive) wave propagation due to current and depth and represents the physical processes of wave generation by wind, dissipation due to whitecapping, bottom friction, depth-induced wave breaking, and nonlinear wave-wave interactions (both quadruplets and triads) explicitly with state-of-the-m1 formulations (Booij et al., 1999; Deltares, 2014b). Wave blocking by currents is also explicitly represented in the model. The SWAN model is based on the discrete spectral action balance equation and is fu lly spectral (across all directions and frequencies). The latter implies that short-crested random wave fields propagating simultaneously from widely different directions can be accommodated (e.g., a wind sea with superimposed swell). SWAN computes the evolution of random, short-crested waves in coastal regions with deep, intermediate, and shallow water depths and ambient currents.

For these analyses, the Delft3D-FLOW and Delft3D-WAVE modules were used to simulate the coupled effects of flow movement (i.e., storm surge) and wave propagation (i.e., wave spectra, height, period, and setup) through a water body (i.e., Lake Michigan and Lake Huron) when acted upon by external forcing functions (i.e., wind and atmospheric pressure fields). The physical features of the numerical model were created from regional and local bathymetry and topography. The model was calibrated and validated to observed historical windstorms (December 1, 1985; December 2, 1990; and October 25, 2010). The antecedent Lake level (i.e., 100-yr high Lake level) is included in the numerical model.

For these analyses, the design synoptic windstorm event is selected in accordance with applicable guidance documents (e.g., ANSI/ANS, 1992; NRC, 2011; NRC, 2013a). ANSI/ANS (1992) and NRC (2011) state the following storm surge combination applies to coastal locations:

• PMSS with wind-wave activity and

• Lesser of the 100-yr or the maximum controlled water level in the enclosed body of water.

This combination event was evaluated for the PMWS occurring coincident with the 100-yr recurrence monthly average Lake level to determine the peak PMSS WSEL at PBNP.

4.4.2 Development of Model Domain The numerical model used a Cartesian coordinate system (Geographic Coordinate System [GCS] NAD27 Albers projection). The ve11ical datum of the model was set so that the 0 m-Model Datum was equivalent to the 100-yr high Lake level (Section 4.4.6).

A detailed numerical model was created from local and regional bathymetric and topographic data sources:

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FPL-076-FHRPR-002, Revision 2

• Lake Michigan and Lake Huron bathymetry (NOAA, 1999a; NOAA, 1999b) was obtained from the National Oceanic and Atmospheric Administration (NOAA) National Geophysical Data Center

,(NGDC) website with an approximate resolution of 90 m (NOAA, 20 14a). The horizontal datum is referenced to the World Geodetic System of 1984, and the vertical datum is referenced to the IGLD85 with a low water datum of+ 176.0 m.

• The 1/3-Arc Second (approximately 10m) National Elevation Dataset (NED) was obtained fi*om the U.S. Geological Survey (USGS) National Map Viewer (USGS, 2011). One NED (n45w88_13) covers the PBNP site area. It is referenced to GCS m-NAD83 (horizontal datum) and m-NA VD88 (vertical datum).

• Recent site topographic and bathymetric surveys were conducted (NEE, 20 14a). Horizontal coordinates reference WISCRS of Manitowoc County (in ft) and elevations are referenced to ft-Plant Datum .

These data required conversion to consistent horizontal (GCS NAD27 Albers projection) and vertical (1 00-yr high Lake level) datums and units for use as the base geometry for the numerical model.

Due to the size, bathymetry and geometry of the Great Lakes, six Delft3D-FLOW domains were necessary.

The coarsest grids represent conditions over Lake Michigan and Lake Huron. The extents of the domains were chosen to include the surrounding coast up to approximately 66 ft (20 m) above the 100-yr Lake level.

A horizontal resolution of 6,562 ft (2,000 m) was chosen to accurately represent the bathymetric contours of Lake Michigan and Lake Huron away fi*om PBNP (Figure 4.1 0).

Near PBNP, a grid resolution of 19.0 ft (5.8 m) was determined to be acceptable to represent PBNP' s coastline and nearshore bathymetry (Figure 4.11 ). In order to resolve the Delft3D-FLOW computations from the coarse grids to the PBNP nearshore grid, refinements of 1 to 7 were applied. A total of three grids were used to pass boundary conditions from the coarser lake grids to the PBNP nearshore grid.

As discussed in Deltares (2014a), mthogonality, aspect ratio, M (horizontal) smoothness, and N (vertical) smoothness limitations cannot be violated by grids using Cartesian coordinates. An evaluation of the estimated Courant number was calculated for each grid to determine the appropriate numerical time step to be used in Delft3D-FLOW simulations. Based on the resolution of the finest grid, a time step of 0.05 min (3 s) was chosen to meet Delft3D-FLOW Courant number (Equation 4.1) limitations (Deltares, 2014a).

The entire spatial domain of Lake Michigan and Lake Huron was enclosed within the coarse Delft3D-FLOW and Delft3D-WA VE grids. Open model boundaries, called "water-water" boundaries (Delta res, 20 14a), are created when the simulation domain covers only a portion of an open body of water.

Boundary condition forcing and reflectivity must be considered when a model domain includes open boundaries. As no open boundaries exist in the Delft3D model, there was no need to specify open water boundary conditions. Delft3D-FLOW grids were joined along each boundary through domain decomposition (Del tares, 20 14a). A total of 12 domain decomposition boundaries were created.

Delft3D-WAVE domain resolutions and extents were identical to the Delft3D-FLOW domains.

Delft3D-WA VE requires nested grids; therefore, each grid covers the extents ofthe finer, nested grids.

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FPL-076-FHRPR-002, Revision 2 4.4.3 Model Processes 4.4.3.1 Delft3D-FLOW Processes In Delft3D-FLOW, the hydrodynamics of storm surge conditions are simulated by solving the Navier-Stokes equations for incompressible free surface flow . The Navier-Stokes equations are reduced to two-dimensional, depth-averaged unsteady flow characterizing stmm surge and ocean currents with Delft3D-FLOW Version 4.00.04.757 (Deltares, 2011). The Navier-Stokes equations for incompressible flow are solved under the shallow water and Boussinesq assumptions. These equations are reduced to an implicit finite difference approximation through the Crank-Nicholson numerical scheme (Deltares, 2014a).

The simplifications incorporated in Delft3D-FLOW allow shallow water shoaling and inundation to be explicitly simulated. A detailed review of Delft3D benchmarking test cases is presented in Walstra and Koster (2006).

Delft3D-FLOW can be used to explicitly simulate open water boundary forcing, bed roughness boundary conditions, air-water boundary forcing through atmospheric inputs (wind and pressure), astronomic forcing on the water column, and direct flow inputs or outputs (inflows from streams, rivers, etc.).

4.4.3.2 Delft3D-WAVE Processes There are three generations of wave models available to compute the sea surface state in Delft3D-WAVE (i.e., SWAN) (Del tares, 20 14b). First generation wave models do not consider nonlinear wave interactions.

Second generation models parameterized these interactions and include the coupled hybrid and coupled discrete fmmulations. Third generation models explicitly represent all the physics relevant for the development of the sea state in two dimensions, without assumptions regarding the spectral space. Fwther, energy terms are described explicitly with the addition of bottom dissipation and reflection, diffraction, and refraction terms. For PBNP, the model computes the sea state from the hurricane using the third generation mode of physics.

The Delft3D-WAVE computations accounted for the following processes (Del tares, 20 14b): depth-induced breaking, nonlinear triad interactions, bottom friction, wind growth, whitecapping, refraction, and frequency shift.

4.4.3.3 Coupled Delft3D-FLOW and Delft3D-WAVE Model To account for the effect of flow on the waves (via setup, current refraction, and enhanced bottom friction) and the effect of waves on current (via forcing, enhanced turbulence, and enhanced bed shear stress), an online coupling ofDelft3D-WA VE with Delft3D-FLOW was performed. The Delft3D-WAVE model has a dynamic interaction with the Delft3D-FLOW module (i.e., two-way wave-current interaction). Through this dynamic coupling, both the effect of waves on current and the effect of flow on waves were modeled.

The Delft3D-FLOW and Delft3D-WAVE models were coupled every 30 min throughout the simulation.

4.4.4 Physical Parameters and Model Constants The following physical parameters are values associated with the conditions and prope1ties of the physical world used to represent surge and wave processes in the numerical model.

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NextEra Energy- PBNP March 6, 20 I5 FPL-076-FHRPR-002, Revision 2 4.4.4.1 Delft3D-FLOW Physical Parameters and Model Constants The physical parameters and constants of the model were selected as follows :

Gravitational Acceleration- A constant gravitational acceleration of 32.2 ft/s 2 (9.8I m/s 2) was used. The National Geodetic Survey, Office of Charting and Geodetic Services, establishes and maintains the basic national horizontal, vettical, and gravity networks of geodetic control (NOAA, I986). The gravitational constant varies slightly across the study area; however, a constant value of32.2 :ft/s2 (9.8I m/s 2) was selected for the model.

Water Density- A freshwater density of 62.4 pcf (I,OOO kg/m 3) was used (Street eta!., 1996).

Air Density- An air density of 0.08 pcf (1.28 kg/m 3) was used (Street eta!., 1996).

Wind Drag Coefficient- The wind drag coefficient is dependent on the wind speed, since the roughness of the water surface varies directly with wind speed. Previous formulations for wind drag were evaluated (Liu, I965; Wuest and Larke, 2003 ; Jensen eta!., 2012; Deltares, 2014a). The wind drag formulation was evaluated as a calibration parameter so that the best fit was selected.

Bottom Roughness- Calibrated, uniform Manning's roughness values were supplied to the Del:ft3D-FLOW model.

Wall Roughness- Due to the large size of the four coarsest Del:ft3D-FLOW domains, the free slip condition was used; in other words, zero tangential shear stress was applied at the model walls. In very large-scale hydrodynamic simulations, the tangential shear stress for all lateral boundaries or vettical walls can be safely neglected (Del tares, 20 II).

Horizontal Eddy Viscosity and Diffusivity- In Del:ft3D-FLOW, for the Reynolds-averaged Navier-Stokes equations, the Reynolds stresses are modeled using the eddy viscosity concept. The horizontal eddy viscosity is mostly associated with the contribution of horizontal turbulent motions and forcing that are not resolved (sub-grid scale turbulence) either by the horizontal grid or a priori removed by solving the Reynolds-averaged shallow water equations (Deltares, 20I1). The value for both horizontal eddy viscosity and horizontal eddy diffusivity depends on the flow and the grid size of the simulation. For large tidal areas with a grid that is hundreds of meters or more, the values for eddy viscosity and eddy diffusivity typically range from 0 :ft2/s to 1,076 :ft2/s (0 m2/s to 100 m2/s). Herbert (1987) found that horizontal eddy viscosity is approximately 538 :ft2/s (50 m2 /s) for the Gulf Stream due to internal waves. Therefore, 538 :ft2/s (50 m2/s) was used in the overall model domain for horizontal eddy viscosity and 538 :ft2/s (50 m2/s) was used for horizontal eddy diffusivity. For the fine grid model domains, a horizontal eddy viscosity of 54 :ft2/s (5 m2/s) was used. Deltares (2014a) recommends a typical value of 1I :ft2 /s to 108 :ft2/s (1 m2/s to 10 m2/s) for grid sizes on the order of I 0 m. Secondary flow, which adds the influence of helical flow to the momentum transport, was ignored due to the large size of the domain area as these flows are insignificant.

4.4.4.2 Delft3D-WAVE Physical Parameters and Model Constants The physical parameters and constants of the model were selected as follows :

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NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding ENERCON NextEra Energy- PBNP March 6, 2015 Excellence-Every project. Every day FPL-076-FHRPR-002, Revision 2 Notth Convention - The direction of notth with respect to the x-axis (i.e., Cartesian convention). The default value of90 degrees (i.e., x-axis pointing east) was selected for the model (Deltares, 2014b).

Wind and Wave Convention- The nautical convention for wind and wave direction was used, which measures the wind vector, so that the angle is the direction from which the waves are coming or from where the wind is blowing (Del tares, 20 14b).

Gravitational Acceleration - A constant gravitational acceleration of 32.2 ft/s 2 (9.81 m/s 2) was used, consistent with the value selected for the Delft3D-FLOW model.

Water Density- A freshwater density of 62.4 pcf (1 ,000 kg/m 3) was used, consistent with the value selected for the Delft3D-FLOW model.

Wave Forces- With the integration of the fully spectral SWAN model within the Delft3D model, it is possible to compute the wave forces on the basis of the energy wave dissipation rate or on the gradient of the radiation stress tensor (Del tares, 20 14b). The radiation stress tensor describes the additional forcing due to the presence of the waves, which changes the mean depth-integrated horizontal momentum in the fluid layer. As a result, varying radiation stresses induce changes in the mean surface elevation (wave setup) and the mean flow (wave-induced currents) (Deltares, 2014b). The wave forces were computed by the radiation stress tensor to account for wave setup in the model.

Depth-Induced Breaking- The process of depth-induced breaking is an improved version of the model proposed by Battjes and Janssen (1978). The model for the rate of dissipation is defined by the alpha and gamma parameters. These physically based values were treated as calibration parameters.

Nonlinear Triad Interactions - In Delft3D-WAVE nonlinear wave-wave interaction computations are carried out with the Discrete Interaction Approximation of Hasselmann et al. (1985). The model is defined by the alpha and beta parameters. These physically based values were treated as calibration parameters.

Similar to results presented in Alkyon (2003), these parameters showed no sensitivity to the model calibration.

Bottom Friction- The JOint Notth Sea WAve Project (JONSW AP) bottom friction formulation was used to represent the bottom friction for wave computations. The JONSWAP method is a semi-empirical methodology developed by Hasselmann et a!. (1973) which uses the CJON parameter to define the bottom roughness. This value was considered a calibration parameter.

4.4.5 Numerical Parameters 4.4.5.1 Delft3D-FLOW Numerical Parameters Advection Scheme for Momentum - In Delft3D-FLOW, three primary algorithms are available: Cyclic, Waqua, and Flooding schemes. In the Lake Michigan and Lake Huron storm surge model, the Cyclic method was used.

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FPL-076-FHRPR-002, Revision 2 Threshold Depth- The threshold depth is the depth above a grid cell which is considered to be wet. The threshold depth must be defined in relation to the change of the water depth per time step in order to prevent the water depth from becoming negative in just one simulation time step (Deltares, 2014a). In order to prevent this, the threshold depth is calculated in such a way that it is larger than the maximum distance the water level can fall over a half time step (the time which the flooding and drying algorithm uses). A threshold depth of 0.03 ft (0.1 m) was chosen based on numerical stability tests.

4.4.5.2 Delft3D-WAVE Numerical Parameters Spectral Space - The amount of diffusion of the implicit scheme in the directional space through the Directional space (COD) parameter and frequency space through the Frequency space (CSS) parameter (Deltares, 2014b).

Directional Space - A value of COD = 0 corresponds to a central scheme and has the largest accuracy (diffusion;::::; 0), but the computation may more easily generate spurious fluctuations. A value of COD= 1 corresponds to an upwind scheme and it is more diffusive and therefore preferable if (strong) gradients in depth or current are present (Del tares, 20 14b). The default value of COD= 0.5 was used in the model.

Frequency Space - A value of CSS = 0 corresponds to a central scheme and has the largest accuracy (diffusion;::::; 0), but the computation may more easily generate spurious fluctuations . A value of CSS = 1 corresponds to an upwind scheme and it is more diffusive and therefore preferable if (strong) gradients in current are present (De !tares, 20 14b). The default value of CSS = 0.5 was used in the model.

Accuracy Criteria - These options influence the criteria for terminating the iterative procedure in the Delft3D-WAVE computation (for numerical convergence criteria). In the PBNP storm surge model, Deltares (20 14b) recommended numerical accuracy criteria were sufficient for maintaining numerical stability.

Temporal Computation Mode - Delft3D-WA VE allows for wave computations to be performed in stationary mode, which conservatively assumes infinite time for development of wave fields from a static constant wind distribution and nonstationary mode, which explicitly accounts for time allowed for development ofwave fields (Deltares, 2014b). Numerical tests run on the Delft3D-WA VE model for Lake Michigan and Lake Huron indicated that the stationary computational method reproduced observed wave distributions with greater accuracy than the nonstationary method. The stationary mode is valid in a case of waves with a relatively short residence time in the computational area under consideration (i.e., the travel time of the waves through the region should be small compared to the time scale of the geophysical conditions, such as the wave boundary conditions, wind, tides, and storm surge) (Deltares, 2014b).

4.4.6 Antecedent Lake Level Delft3D-FLOW and Delft3D-WAVE simulations ofPMSS at PBNP used the 100-yr high Lake level as the antecedent condition. Simulations of the low water effects at PBNP used the 100-yr low Lake level as the antecedent water level.

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FPL-076-FHRPR-002, Revision 2 The 100-yr recurrence monthly average high and low water levels near PBNP were derived using a log-Pearson Type III statistical analysis. The estimated water levels were determined from two NOAA water level recording stations near PBNP: Kewaunee, Wisconsin (Station ID 9087068) (NOAA, 2014c) and Milwaukee, Wisconsin (Station ID 9087057) (NOAA, 2014h). Table 4.3 summarizes the results of the frequency analysis.

The most conservative high and low 100-yr Lake levels from Table 4.3 were used in subsequent analyses:

a 100-yr recurrence monthly average high water level of +583.1 ft-NA VD88 (+ 1.8 ft-Piant Datum) was used in the PMSS and seiche evaluations 4 and a 100-yr recurrence monthly average low water level of

+575.6 ft-NA VD88 (-5.7 ft-Plant Datum) was used in the low water effects evaluation.

4.4. 7 Probable Maximum Windstorm Development The synthetic probable maximum synoptic events are developed in accordance with applicable guidance documents (ANSI/ANS, 1992; NRC, 2011 ), which provide the basis for the site-specific storm methodology.

The spatially and temporally variable wind and pressure fields for each simulation were created using historically extreme storm events. The wind and pressure data for the probable maximum synoptic events were provided in 3-hr and 6-hr average intervals utilizing the NWS model reanalysis data (NOAA, 2014jj; NOAA, 20 14kk; NOAA, 20 14ll) and in 1-hr increments based on manual analysis for synthetic squall line events.

Most of the historical instances of sustained winds over 50 mph (22 rn/s) in the Great Lakes region are associated with deep low pressure areas which move through the region from the southwest to the nmtheast.

The general synoptic pattem is one in which the deep low pressure area results in a strong pressure gradient between the storm's center and the high pressure region to the north or west. Strong winds result from strong gradients. When the gradient is extreme and lasts for days, very strong winds can persist for an extended period. Due to the preferred track directions, the vast majority of the strongest sustained winds occur from the south or southwest. Low pressure centers as low as 955 mbar (equivalent to a Category 3 hurricane) have occurred near PBNP.

In other cases, tropical systems making landfall along the Gulf of Mexico coast or U.S. east coast move inland (e.g., Hurricane Hazel in 1954, Hurricane Sandy in 2012). By the time these storms reach the Great Lakes region, they have transitioned into extratropical cyclones; however, the general circulation and deep low pressure center persist. Thus, strong winds can remain. The preferred track direction of these storms is to the northwest, notth, or nmtheast.

Three-Iu* or 6-lu* wind and pressure data for 31 historical synoptic events from 1907 to 2012 were evaluated, which produced 45 maximized, potential synoptic PMWS scenarios (Table 4.4). Each scenario was maximized and transposed to occur directly over PBNP. Since pressure gradients are directly linked to strong winds, the analysis inherently captured the worst-case wind and pressure pattems that could reasonably be expected at PBNP. A comparison to regional weather station data revealed that the stotms listed in Table 4.4 significantly exceeded a 100,000-yr return period (i.e., 1o-s annual frequency) . When 4

The antecedent water level for all calibration and validation simulations was the present-day Lake level.

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NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding ENERCON NextEra Energy- PBNP March 6, 2015 Excellence-Every project. Every day FPL-076-FHRPR-002, Revision 2 combined independently with the 100-yr recurrence monthly average Lake level (i.e., less than 10*2 annual frequency), the combined PMSS event will have an annual frequency less than 10*6 .

4.4.8 Storm Surge Model Calibration 4.4.8.1.1 Calibration Overview Calibration and validation of a stmm surge model are critical to the success of PMSS modeling, the defensibility of the technical approach, and ultimately to acceptance of PMSS results. As required by NRC (20 11), the parameters of a given model may be calibrated using data of relatively large historical storm events and then validated on comparable storm events not used in the calibration. To verify the prediction capability of the coupled Delft3D-FLOW and Delft3D-WAVE model, calibration and validation are performed by comparing the model water level and wave outputs with measured historical storm surges and significant wave heights (Hs) for three independent storm events.

4.4.8.1.2 Historical Synoptic Events The model is calibrated and validated with observed historical storms (December 1, 1985; December 2, 1990; and October 25, 2010). The October 25, 2010 event was constructed at a 3-hr temporal resolution.

The December 1, 1985 and December 2, 1990 events were constructed at a 6-h.r temporal resolution based on availability of historical meteorological observations.

4.4.8.1.3 Historical Surge and Wave Observations Observed storm surge time series recorded at NOAA tide stations (NOAA, 20 I 4b through NOAA, 20 14r) were used to calibrate the simulated storm surges (Table 4.5; Figure 4.12). The observed wave characteristics time series recorded at NOAA buoy stations (NOAA, 2014s through NOAA, 2014gg) were used to calibrate the simulated wave fields (Table 4.6; Figure 4.13).

4.4.8.1.4 Selection of Calibration I Validation Events The October 25, 2010 storm was selected as the calibration event due to the finer temporal resolution of the atmospheric wind and pressure data (i.e., 3 hr versus 6 hr), as well as the availability of observed storm surge and wave characteristics (Table 4.5; Table 4.6). The remaining historical storms discussed above were used as model validation.

4.4.8.1.5 Calibration Methodology A typical calibration procedure consists of three steps that are repeated until the simulation results are deemed accurate enough for the desired application: (1) running the model; (2) crosschecking the results against actual measured data; and, if necessary, (3) adjusting the model parameters. In each case, simulation results are compared with measured (historical) observations obtained with other parameter values.

Knowledge is gained about the sensitivity of the different parameters in the model.

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NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding ENERCON NextEra Energy- PBNP March 6, 20 I 5 Excellence-Every project. Every day. FPL-076-FHRPR-002, Revision 2 The objective functions Root Mean Square Error (RMSE) and Nash-Sutcliffe model quotient efficiency (NSE) were used to maintain an objective view of model calibration adjustments (i.e., Step (3) described above).

Lr=l(yg- Y~/

RMSE= Equation 4.2 n

t t )2

( Yo-Ym NSE = l - "n Equation 4.3 L.t=l ( t Yo- Ybar 0

)2 where:

t =time step; n =total number of time steps; yo =observed value; Ym = simulated value; and YbarO = average of all observed values.

The NSE provides a quantitative measure of model performance on the interval (-oo, 1) (Nash and Sutcliffe, 1970). Values closer to I suggest better model performance, whereas values closer to -oo indicate poor model performance. An NSE value of 0 suggests the model's predictive power is equal to a model that simply reproduces the average of the observed time series. Numerical models producing an NSE value of 0 or less add no additional value. An NSE value of 1 suggests an ideal model that has no error in reproduction of observed data. Values between 0 and 1 suggest that use of the model adds value to the prediction; however, the transformation is not ideal. The RMSE represents the sample standard deviation between simulated and observed values.

The calibration and validation of the PBNP Delft3D-FLOW and Delft3D-WAVE model were completed as follows:

• Selected an historical calibration event based on availability of observed storm surge data, the available resolution of the wind and pressure forcing data, and the magnitude of the event.

• Performed a series of sensitivity simulations of the wind drag coefficient for the calibration event.

Calculated the objective functions RMSE and NSE of the WSEL time series to determine the calibration value for Delft3D-FLOW.

• Performed a series of sensitivity simulations of the Manning's roughness for the calibration event.

Calculated the objective functions RMSE and NSE of the WSEL time series to determine the calibration value for Delft3D-FLOW.

• Performed a series of sensitivity simulations of the Delft3D-WAVE solution technique to determine if a stationary or nonstationary solution produces more ideal results. Calculated the objective functions RMSE and NSE of Hs time series to determine the appropriate solution for Delft3D-WAVE. Reviewed peak wave period (T) and wave direction to verify model predictions .

• Performed a series of sensitivity simulations on the CmNbottom friction coefficient. Calculated the objective functions RMSE and NSE of Hs time series to determine the calibration value for Delft3D-WAVE. Reviewed T and wave direction to verify model predictions.

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FPL-076-FHRPR-002, Revision 2

• Performed a series of sensitivity simulations of the depth-induced breaking y parameter. Calculated the objective functions RMSE and NSE of Hs time series to determine the calibration value for Delft3D-WAVE. Reviewed T and wave direction to verify model predictions.

• Ran the remaining events as validation to determine if the final calibration parameter values are acceptable for storm surge modeling. Observed wave data exist only for the 201 0 event; therefore, only WSEL (i.e., Delft3D-FLOW) validation was performed.

4.4.8.1.6 Calibration Results Wind Drag Formulation- Several formulations for the wind drag coefficient over enclosed bodies of water have been proposed tlu*oughout the scientific literature. Liu (1965) studied wind waves generated over the Lake and proposed an empirical wind drag relationship. Jensen et al. (2012) similarly developed a wind drag relationship for the Lake through model calibration. Wuest and Lorke (2003) performed experiments on enclosed bodies of water and proposed an empirical wind drag relationship. For comparison, the default wind drag relationship proposed in De!tares (20 14a) was also evaluated.

Documentation of all model calibration iterations is presented in Table 4.7. Final calibration results are presented for NOAA Station ID 9087068 (Figure 4.14) and NOAA Buoy 45022 (Figure 4.15). Storm surge validation results are presented on Figure 4.16 and Figure 4.17, respectively. The following sections discuss the selection of final model calibration parameter values.

The ambient ice cover of the Great Lakes was evaluated for each calibration and validation event. Wang et al. (2012) demonstrate that ice cover was minimal for the 2010 calibration event. Assel (2014) demonstrates that ice cover for the 1985 and 1990 validation events was also minimal. The presence of some ice cover may have a conservative effect on the wind drag coefficient (Jensen et al., 2012).

Tlu*ough calibration to observed WSEL data for the 2010 event, it was determined that the relationship proposed in Liu (1965) best reproduced the observed WSELs (Table 4.7).

Bed Roughness - Bed roughness in the Manning's roughness formulation was treated as a calibration parameter; therefore, the final accepted value was determined through calibration. An initial value of 0.02 was selected based on discussion in Deltares (2014a). The roughness value was increased in each run. The RMSE and NSE objective function values did not significantly change between 0.03 and 0.04; therefore, a final value of 0.04 was selected.

JONSWAP Bottom Friction Coefficient (CmN)- The bottom friction model selected for Delft3D-WA VE is the empirical model of JONSW AP. The Delft3D-WAVE User Manual suggests Cson oM = CmN =

0.410 ft2s-3 (0.03 8 m2s- 3) for swell conditions and CmN = 0.721 ft 2s- 3 (0.067 m2s- 3) for fully developed wave conditions in shallow water. For the computational wave grid in this calculation, the bottom friction parameter (CmN) is determined using model calibration, using CmN= 0.721 ft 2 s- 3 (0.067 m2 s- 3) for the initial trial run.

The JONSWAP bottom friction coefficient was varied within the acceptable parameter range (0.06 to 0.075) (Deltares, 2014b). The results show no sensitivity to the CmN parameter (Figure 4.18). Alkyon (2003) similarly performed sensitivity analysis of CmN over several case studies and reached the same conclusion.

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FPL-076-FHRPR-002, Revision 2 Depth-Induced Breaking a Parameter - The depth-induced breaking a parameter was found to be not sensitive to the prediction of wave characteristics . This conclusion is similar to that presented in Alkyon (2003). This parameter was left at the default Delft3D-WA VE parameter value (Deltares, 2014b).

Depth-Induced Breaking y Parameter - The depth-induced breaking y parameter was varied within the acceptable parameter range (0.55 to 1.2) (Deltares, 2014b). As the depth-induced breaking only affects waves in shallow water, only results from Buoy 45022 were evaluated. The lower limit of the depth-induced breaking parameter (0.55) produced the most statistically significant calibration results (Table 4.8 for overall results and Figure 4.19 and Figure 4.20 for results at Buoy 45022).

Nonlinear Triad Interactions- Similar to results presented in Alkyon (2003), the parameters controlling the simulation of nonlinear triad interaction were not sensitive in the prediction of wave fields. These parameters were left at the default Delft3D-WAVE parameter values (Del tares, 20 14b).

4.4.8.1.7 Summary of Final Calibrated Model Parameters A summary of all the parameters used in the Delft3D-FLOW and Delft3D-WAVE models is presented in Table 4.9 and Table 4.10.

4.4.9 Probable Maximum Storm Surge Methodology 4.4.9.1 Overview of Probable Maximum Storm Surge Methodology The following steps were followed to evaluate the PMSS at PBNP:

• Simulated each hypothetical maximized and transposed synoptic event with the calibrated Delft3D-FLOW and Delft3D-WAVE model discussed in Section 4.4.8.

• Post-processed model results of each scenario to determine the time series of the PMSS SWL, Hs, and T.

• Calculated the runup for each scenario using an empirical formulation for wave runup on a gently-sloping impermeable surface (USACE, 2008). The scenario that produced the peak WSEL (i.e., PMSS SWL plus coincident wave run up) was determined to be the bounding PMWS scenario.

• Simulated the critical PMWS event(s) with the critical peak wind location while applying the overland to overtake and averaging duration adjustments to the PMWS meteorological forcing data to determine the PMSS.

• Calculated the wave runup on near vertical slope to determine the peak WSEL.

• Estimated the durations of flooding for which the peak WSEL was above +588.3 ft-NA VD88

(+7.0 ft-Piant Datum), +589.3 ft-NA VD88 (+8 .0 ft-Plant Datum), and +590.3 ft-NA VD88

(+9.0 ft-Plant Datum) from the bounding synoptic PMWS event.

4.4.9.2 Simulation of Maximized Synoptic Events Each hypothetical maximized and transposed synoptic event was simulated with the calibrated Delft3D-FLOW and Delft3D-WA VE models discussed in Section 4.4.8. The results of the Delft3D Page 44 of69

,.. ENERCON Excellence-Every project. Every day NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding NextEra Energy- PBNP March 6, 2015 FPL-076-FHRPR-002, Revision 2 simulations were evaluated to the no11h and south of the CWPH to determine the bounding event and location (Figure 4.21 ).

4.4.9.3 Calculation ofRunup on an Impermeable Gently-Sloping Surface Run up was calculated for wave characteristics simulated at Observation Points 1 and 2 (Figure 4.2 I).

Figure 4.22 demonstrates the PMWS-induced waves break completely along the beach and discharge flumes east of the CWPH and TB.

Wave runup was calculated for all potential PMSS scenarios using the empirical formula for runup on a smooth, impermeable slope as presented in USACE (2008). The equations for the calculation of run up are as follows:

Equation 4.4 Ru2%

Hs

= (A7+B)y

~

y y y r b h P Equation 4.5 where:

( =breaker number or Iribarren number (dimensionless);

¢ =beach slope (radians);

Ho =deep water wave height (m);

Lo =deep water wave length (m);

Ru2% = runup level (m) exceeded by 2 percent of breaking waves; Hs =significant wave height (m);

A, B s

=coefficients dependent on (dimensionless);

Yr =surface roughness reduction factor (dimensionless);

Yb =berm influence reduction factor (dimensionless);

Yh =non-Rayleigh distribution reduction factor (dimensionless); and yp = angle of incidence reduction factor (dimensionless).

Coefficients A and Bin Equation 4.5 are dependent on wave steepness((). The base equation is presented for runup on a smooth surface. The coefficient Yr accounts for wave runup reductions due to the presence of riprap (i.e., rough surface), such as that present at PBNP. The total combined reduction factor (i.e., the product ofYrYbYhYp) was set to be greater than or equal to 0.5. Calculated wave runup is added to the simulated PMSS SWL to determine the peak WSEL resulting from each scenario.

4.4.9.4 Sensitivity of Maximum Wind Location An additional sensitivity of the PMWS scenario was conducted by shifting the PMWS wind and pressure fields one and two meteorological grid cells (horizontal resolution: approximately 20 mi [32 km]) east of PBNP to determine if peak winds further over the Lake (rather than directly over PBNP) would produce a higher storm surge.

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FPL-076-FHRPR-002, Revision 2 4.4.9.5 Ovenvater Wind Speed Adjustment The bounding synoptic event wind speeds developed were representative of overland wind speeds. As events observed occurring overland are transposed over Lake Michigan and Lake Huron, an adjustment is applied to account for the estimated overwater wind speeds of the same event.

As discussed in Schwab and Morton (1984), the wind speed developed over open water often differs from that developed overland. Four relationships between overland and overwater wind speeds are proposed in Schwab and Morton (1984) (Figure 4.23). The relationship in Equation 4.6 was determined to be the most appropriate by the authors when evaluated against observed wind speed data:

Equation 4.6 where:

Uw = overwater wind speed (m/s);

UL =overland wind speed (m/s); and CiJ =constant (dimensionless) that is a function of the air-water temperature difference (L11) and UL.

NOAA Buoy 45007 was used to compile 10 yr (2004 to 2013) of observed air and water temperature observations. The distribution of LJT was calculated (Figure 4.24). The 95 percent exceedance value of -6° Celsius was conservatively used to determine CiJ(Figure 4.23).

A UL value of 33 ft/s (1 0 m/s) was assumed as these coefficients are applied to potential PMWS events. A value of 1.42 for CiJ was determined from Figure 4.23 and Figure 4.24. The entire PMWS wind field was modified by this constant.

4.4.9.6 Wind Speed Averaging Duration Adjustment When evaluating wave generation in water bodies of different sizes, different wind speed averaging intervals are appropriate. The USACE Coastal Engineering Manual (CEM) notes that if extreme wind speeds are being considered, wind speeds should be adjusted from the averaging interval of the observation to an averaging time appropriate for wave prediction (USACE, 2008). As per ANSI/ANS (1992),

Section 7.2.2.3.4, hourly values of pressure and wind fields should be used for each grid point of the water body. Additionally, the USACE Great Lakes Coastal Flood Study (USACE, 20 12) notes that if measured wind data are averaged at different time intervals (U;) than a 1-hr average (UJ6oo), adjustment to a 1-lu-averaging interval is recommended for the wave modeling application. CEM Figure II-2-1 (USACE, 2008, page II-2-4), which also includes the best-fit equations, was used for the wind speed averaging duration adjustment:

U*

- ' - = -0.15 log(ti) + 1.5334, where: 3,600 < ti < 36,000 seconds Equation 4.7 u36oo where:

U; =is wind speed (m/s);

UJ6oo = 1-h.r wind speed (i.e., 3600 s wind speed) (m/s); and t; =duration of i (s).

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NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding NextEra Energy - PBNP ENERCON March 6, 2015 Excellence- Every proj ect. Every day FPL-076-FHRPR-002, Revision 2 For all wind forcing data developed with a 3-hr time step, a constant velocity adjustment for the 3-hr (i.e.,

t,= l 0,800 s) averaging interval was developed as follows:

___l!j_

u3 6oo

= -0.15Iog(ti) + 1.5334 = 0.928386 Equation 4.8 u36oo = (___l!j_)-1 = 1.077 Equation 4.9 ui u 36oo 4.4.10 Storm Surge Results 4.4.10.1 Synoptic Event Screening Table 4.11 presents the peak WSEL for each synoptic event and the coincident breaking water depth (h),

Hs, T, and wave runup (R) calculated for a smooth impermeable sloped surface, based on the methodology described in Section 4.4.9.3 . Scenario 13 (i.e., the January 10-12, 1975 event from the southeast direction) produced the highest peak WSEL and was concluded to be the bounding PMWS case (Table 4.11).

4.4.10.2 Probable Maximum Storm Surge Maximum Water Surface Elevations The overwater wind adjustments and sampling interval adjustments described in Section 4.4.9.5 and Section 4.4.9.6, respectively, were applied to the bounding PMWS synoptic event (i.e., Scenario 13) to determine the PMSS and peak WSEL at PBNP. The results of the PMSS are presented in Table 4.12 and Figure 4.25 .

The WSEL at the maximum SWL, shown on Figure 4.25, is lower than plant grade at the CWPH and TB.

Thus, no standing water is present at any PBNP POls during the PMSS event. The location of 100 percent PMSS wave breaking occurred approximately 50ft (15m) east of the closest POI, Door 336 on the southern side of the CWPH (Figure 4.22). Therefore, wave runup on a vertical structure was not applicable for PBNP.

Rather, the wave runup was calculated using Equation 4.5 , as discussed in Section 4.4.9.3. Results of the PMSS and runup calculation are presented in Table 4.12. The runup on a gently-sloping impermeable surface reached a maximum WSEL of +589.7 ft-NA VD88 (+8.4 ft-Plant Datum) (Figure 4.26). The formulation accounted for the effects of surface roughness, berm elevation, and wave refraction on wave runup height; however, the maximum combined reduction factor was limited conservatively to 0.5.

However, the lateral landward extent of ove1topping is limited by the transfer of kinetic to potential energy as overtopping runup flows over a berm/riprap crest.

Since the PMSS SWL, +585.8 ft-NA VD88 (+4.5 ft-Pl ant Datum), at the time of maximum PMSS WSEL is slightly below the top of the riprap slope (approximately +586.3 ft-NA VD88 [+5.0 ft-Plant Datum]) on the south side of the CWPH/forebay, the wave runup will ove1top the berm and flow towards the CWPH.

Additional frictional losses and flow expansion between the riprap slope and CWPH were not considered.

Accordingly, the actual maximum WSEL at the wave barrier installed adjacent to CWPH rollup Door 336 is expected to be slightly less than that calculated (+589.7 ft-NA VD88 [+8.4 ft-Plant Datum]). Figure 4.27 shows a map view of the maximum PMSS inundation, including the estimated lateral extent of wave runup ove1topping the riprap slope protecting the beach.

The duration of inundation is estimated to be I 020 min, 120 min, and 0 min for +588.3 ft-NA VD88

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(+9.0 ft-Plant Datum), respectively (Figure 4.26). These durations are provided conservatively at the landward edge of the riprap slope and do not consider frictional losses or flow expansion as the ove1topped water travels towards the CWPH.

4.5 Seiche The same computer-based numerical model used in the PMSS evaluation (developed using the Delft3D Version 4.00.01 software package [Deltares, 2011]) was used to estimate the maximum seiche from a suite of theoretical design storms. Synthetic squall line (derecho) events were developed in accordance with applicable guidance documents (e.g., ANSVANS, 1992; NRC, 2011; NRC, 20 13a), which provide the basis for the site-specific storm methodology.

The maximum seiche at PBNP was evaluated from site-specific maximized squall line (derecho) events moving across the Lake. ANSI/ANS (1992) and NRC (2011) state the following storm surge combination applies to coastal locations:

• Maximum seiche with wind-wave activity and

• Lesser of the 100-yr or the maximum controlled water level in the enclosed body of water.

This combination was evaluated to determine the peak seiche SWL occurring coincident to the 100-yr recurrence monthly average high Lake level at PBNP.

4.5.1 Squall Line Event Development Historical squall lines (or derechos), which are widespread straight-line windstorms associated with fast-moving bands of severe thunderstorms, were analyzed. The winds in these storms can produce some ofthe highest instantaneous recorded wind gusts, but last only for a shmt time (i.e., less than 30 min) at a given location. A squall line can advance hundreds of miles during its lifetime; some squall li.nes have formed over the U.S. upper Midwest and advanced across the Great Lakes to the U.S . east coast. Squall lines occur exclusively during the warm season, generally from April through August.

Squall lines have multiple characteristics that eliminate them from PMWS consideration (with respect to PMSS):

• Shmt durations at pa~ticular locations due to fast forward speeds;

• It is physically impossible to have two consecutive squall lines over the same region due to the significant time required to recharge the required atmospheric parameters (i.e., at least 12 hr); and

• Squall line events do not occur within low pressure systems or remnant tropical storms (i.e.,

synoptic events) and would not be considered coincident with those discussed in Section 4.4.7.

Seventeen historical squall lines between 1909 and 2012 were analyzed to develop maximized, transposed squall lines (derechos). These synthetic storms were evaluated for potential seiches independent of the ,

PMSS. Since the squall lines initially move offshore at PBNP, the flooding impact at PBNP will be indirect:

the primary storm surge will occur along the eastern and/or southern shorelines of the Lake. The seiche will Page 48 of69

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NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding NextEra Energy - PBNP March 6, 2015 FPL-076-FHRPR-002, Revision 2 then propagate to the west and/or nmth after the squall line has passed completely over the Lake, due to the water surface gradient induced by pressure and winds of the squall line.

4.5.2 Model Development The calibrated numerical model developed to evaluate the PMSS was used for the seiche analysis. Refer to Section 4.4.2 through Section 4.4.6 and Section 4.4.8 for details of the numerical model. The same antecedent Lake level (i.e., 0 m-Model Datum) was used for the seiche simulations. A validation run of an historical squall line event was conducted to ensure the calibrated PMSS model functioned as expected (i.e., produced similar seiche amplitudes and periods) for the seiche evaluation (Section 4.5.3).

4.5.3 Seiche Model Validation The July 13-14, 1995 derecho event was evaluated to compare to the historical observations at Goderich, Ontario (Canada) and Port Huron, Michigan in Lake Huron to ensure the model accurately reproduced the recorded seiche amplitudes and periods (Figure 4.28). The model replicated the overall period of seiche oscillations. The maximum difference between positive and negative amplitudes was also similar at each location, although there was a slight shift to the positive direction (i.e., higher average SWL). Thus, it was concluded that the calibrated PMSS model was sufficient to use for the seiche evaluation without additional modifications.

4.5.4 Maximum Seiche Results 4.5.4.1 Squall Line Event Screening Four characteristic squall line events were used in the initial screening simulations: July 19-20, 1983; July 13-14, 1995; May 31, 1998; and April 19-20, 2011. It was found that the July 13-14, 1995 and May 31, 1998 derecho events produced the highest seiche amplitudes and would be analyzed further through transpositioning and maximization. The former event had sustained winds from the nmthwest, while the latter had significant east-to-west winds.

4.5.4.2 Squall Line Event Tnnsposition Sensitivity tests were completed by shifting the squall line pressure and wind fields to find the most critical case at PBNP. The overwater and duration corrections, detailed in Section 4.4.9.5 and Section 4.4.9.6, respectively, were applied in conjunction with a linear pressure decrease of 5 mbar.

4.5.4.3 Maximum Seiche Still Water Level The maximized, transposed May 31, 1998 derecho event generated the largest seiche amplitude (+ 1.0 ft

[+0.3 m]) at PBNP (Figure 4.29), such that the total maximum SWL above the 100-yr recurrence monthly average high Lake level due to a seiche event was +584.1 ft-NA VD88 (+2.8 ft-Plant Datum) (Table 4.13).

The maximum SWL was bounded by the maximum PMSS SWL; further, Hs during the PMSS event would be greater than during the seiche event since the seiche event occurs at PBNP after the squall line (derecho) has passed over the Lake and waves during the PMSS are generated by strong local winds. Thus, the peak Page 49 of69

NTTF Recommendation 2. I (Hazard Reevaluations): Flooding ENERCON NextEra Energy- PBNP March 6, 20 I 5 Excellence-Every project. Every day FPL-076-FHRPR-002, Revision 2 WSEL during the maximum seiche event is bounded by the peak PMSS WSEL (Section 4.4. I 0) and does not need to be numerically computed.

This SWL result is for a single squall line event. To amplify the initial seiche amplitude, forcing would need to be applied to the Lake at a resonant frequency to the basin's geometry. A fast Fourier transform was performed to establish the Lake's natural periods of oscillations. The dominant frequencies were found to be 40 min, 90 min, and I I 0 min. As discussed in Section 4.5 . I, subsequent strong squall lines must be spaced at least I2 lu* apatt in order for the necessary atmospheric conditions to recharge. Thus, a series of squall line or derecho events occurring at the Lake's characteristic resonant frequencies are physically impossible. Seiche amplification above the+ I .0 ft (+0.3 m) produced in the model simulations at PBNP is implausible.

4.6 Probable Maximum Tsunami The potential sources of a tsunami that may cause a probable maximum tsunami (PMT) for PBNP were analyzed from observational records and current scientific literature. Queries were performed in the NGDC tsunami, earthquake, and volcano databases to determine whether any historical events were rep01ted regionally or near PBNP (Figure 4.30) (NOAA, 20I4hh). The USGS database was queried for any possible tsunamigenic landslide activities in the Great Lakes, specifically Lake Michigan (USGS, 20I4a; USGS, 2014b).

No historical evidence was found of a potential tsunami occurring at or near PBNP due to earthquake (Figure 4.3 I), landslide, or volcanic activity. The New Madrid eatthquakes of I 811-1812 in Missouri were felt near PBNP (in Orchard Lake, Michigan) but a tsunami runup was not observed in the Lake (Lockridge et a!., 2002). The only historical "tsunami runup" events located in the databases were related to meteorological events; these events were not classified as true tsunami events but rather seiches (Section 4.5).

4.7 Ice-Induced Flooding and Effects NRC (20 11) states that "in the hierarchal hazard assessment framework, it may be possible to determine whether a flood caused by another flood-causing mechanism at or near the site may exceed that resulting from an ice event. If such an alternative and bounding flood is found, no fmther analysis for the ice-induced flooding is necessary." Accordingly, a calculation was completed to determine whether ice-induced flooding would require fmther hydraulic modeling analysis, or if another flood scenario is bounding.

The USACE Ice Jam Database (USACE, 20I4) was queried to obtain information regarding historical ice events located in the Manitowoc-Sheboygan Watershed . No ice jams were identified. Therefore, fmther consideration of ice-induced flooding (including the effects offrazil ice) was not required.

4.7.1 Ice Cover Records regarding ice cover on the Lake were obtained from the U.S. National Ice Center (USNIC) website (USNIC, 20I4). These records consist of Daily Ice Analysis Chatts (DIAC) and are available (digitally) from 1995 tlu*ough the present.

The winter of2013-2014 was the worst on record with regard to ice coverage on the Lake (NOAA, 20I4ii).

Therefore, the DIAC for 20I3-2014 (tlu*ough March 7, 2014) were reviewed to obtain the maximum Page 50 of69

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding NextEra Energy- PBNP March 6, 2015 Excellence-Every project. Every day FPL-076-FHRPR-002, Revision 2 recorded ice thickness for the area of the Lake adjacent to PBNP: 1.0 ft (0.30 m) from March 3, 2014 through March 7, 2014.

Review of the DIAC indicates that ice thickness was greatest at the far northwest area of the Lake (Sturgeon Bay), with a maximum overall ice thickness from February 23, 2014 through March 7, 2014 of 3.9 ft (1.2 m).

4.8 Channel Migration or Diversion PBNP is located on Lake Michigan with no major streams or rivers nearby. Therefore, channel migration or diversion is not an applicable flooding hazard.

4.9 Combined Events Flooding The combination flooding analysis was performed in accordance with guidelines in ANSI/ANS (1992) and NRC (2011). PBNP is a "shore" location on an "enclosed body of water." For this location, combined event flooding involving surges, seiches, tsunamis, and tides might produce maximum flood levels.

Because PMP flooding of streams and rivers cannot affect the site, combined events involving a riverine PMF will have no impact on PBNP. Because there are no dam failure-related flooding hazards, dam flooding combinations are precluded fi*om analysis. Thus, the only combined event flood hazard is the storm surge-related combination:

• PMSS and seiche with wind-wave activity and

• Lesser of the 100-yr or the maximum controlled water level in the enclosed body of water.

This combination is the same as that analyzed in Section 4.4 and Section 4.5 for PMSS and seiche, respectively. Refer to those sections for the descriptions and results of the analyses.

4.10 Low Water Effects NRC (2013a) states that "drawdown may be an issue when SSCs depend on water sources where storm surge or seiche may affect the availability of water." Accordingly, low water effects were simulated using the same calibrated numerical model as the PMSS and maximum seiche evaluations. The antecedent Lake level was the 100-yr recurrence monthly average low Lake level of +575.6 ft-NAVD88

(-5.7 ft-Plant Datum), which was set at -2.3 m-Model Datum. The two worst-case squall line events (discussed in Section 4.5) and eight synoptic events (four shifted and four transposed) were evaluated to determine which produced the minimum SWL at PBNP. This case was then modified with the overwater and duration corrections detailed in Section 4.4.9.5 and Section 4.4.9.6, respectively.

The results from the nine (i.e., eight screening and one final) low water simulations are listed in Table 4.14.

The bounding case was the maximized October 29 to November 1, 2012 synoptic event from the nmthwest, shifted nmth with wind corrections applied. The minimum SWL was +572.3 ft-NA VD88

(-9.0 ft-Plant Datum), produced by a setdown of -3.3 ft during the October 29, 2012 to November 1, 2012 northwest transposed synoptic event, shifted north with the overwater and duration corrections.

4.11 Hydrostatic, Hydrodynamic, and Sediment Loading Neither the PMSS nor maximum seiche peak produced standing water at the POls shown on Figure 4.5.

However, the peak PMSS WSEL indicated wave runup could reach the wave barrier adjacent to Door 336 Page 51 of69

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding ENERCON NextEra Energy- PBNP March 6, 2015 Excellence- Every project. Every day.

FPL-076-FHRPR-002, Revision 2 on the southern side of the CWPH. The only other applicable flooding-induced loadings result from the LIP event.

4.11.1 Local Intense Precipitation Loading The static (i.e., hydrostatic) and impact (i.e., hydrodynamic) forces were determined from the modeled WSEL and velocity time series at each POI. The hydrostatic pressure increases in proportion to the water depth due to the increasing weight that is exetted from above. From USACE (2008), the hydrostatic pressure varies fi*om zero at the water surface to a maximum at the base of the wall, given by:

Equation 4.10 where:

Ps = hydrostatic pressure (psf);

Yw =specific unit weight of freshwater (=62.4 pet); and hw =water depth (ft).

Once the maximum static pressure was calculated, a maximum hydrostatic force per horizontal unit length was then calculated:

Equation 4.11 where:

Fs = maximum hydrostatic force per horizontal unit length (lbs/ft);

= hydrostatic pressure (psf); and

=water depth (ft).

The hydrodynamic impact pressure due to the velocity of LIP surface runoff was estimated using the velocity time series at each POI. From FL0-2D (2013), the hydrodynamic pressure (pd) is represented by:

Equation 4.12 where:

pd =hydrodynamic impact pressure (psf);

k =empirical coefficient (dimensionless);

Pf =freshwater density (=1.94 slugs/ft3); and v =maximum velocity (ft/s).

A maximum hydrodynamic force per horizontal unit length (Fd) was then calculated:

Fd = Pdhd Equation 4.13

=maximum hydrodynamic force per horizontal unit length (lbs/ft);

= hydrodynamic impact pressure (psf); and

=water depth at maximum velocity (ft/s).

The maximum static and impact forces were summed to determine the maximum total force at each POI through the LIP event. The resulting static, impact, and total forces for LIP Scenario A and Scenario B are listed in Table 4.15 at each PBNP POI. The maximum total force occurred during Scenario B for most Page 52 of69

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding p:* ENERCON NextEra Energy- PBNP March 6, 2015 Excellence- Every proj ect. Every day FPL-076-FHRPR-002, Revision 2 POls due to the excess ponding near the CPWH and TB caused by the runoff obstruction from the temporary wave barriers. For the two CWPH doors protected by the temporary wave barriers (Door 336 and Door 340), the impact forces were computed from the computational cells adjacent to the wave barriers.

Since the temporary barriers and sandbags are expected to eliminate impact forces (i.e., flowing water) at the doors, the listed hydrodynamic forces are conservative.

The drainage area for PBNP consists mostly of concrete and paved surfaces which contain very few unconsolidated pariicles. The only area of predominantly unconsolidated material is along the beach east of the CWPH which, due to the topography, does not drain towards the power block. Thus, significant sediment accumulation at any evaluated POI is not expected.

4.11.2 Probable Maximum Storm Surge Loading During the peak of the PMSS event, some wave runup is expected to reach the wave barrier adjacent to CWPH Door 336. A surging breaking wave force was calculated at the wave barriers and would be bounding for all PBNP POls. The breaking wave force was computed with a relationship presented in USACE (2008):

Equation 4.14 where:

Fsurge =breaking wave force (lbs/ft);

Yw =specific unit weight offreshwater (=62.4 pcf);

Hb =breaking wave height (ft);

X1 =lateral distance from SWL to structure in runup zone (ft);

jJ =beach slope (degrees); and Ra =wave runup above SWL (ft).

For a breaking wave height (Hb) of 2.4 ft, lateral distance (X1) of 50 ft (15 m), beach slope (fJ) of 3.57 degrees, and total runup height (Ra) of 3.9 ft, the total breaking wave force (Fwrge) was found to be approximately 3 lbs/ft. This loading is bounded by the total hydrostatic and hydrodynamic loading at Door 336 during the LIP Scenario A event, 278 .2 lbs/ft (Table 4.15).

4.12 Debris and Waterborne Projectiles Guidance states that debris loads on SSCs impo1iant to safety should be considered and that the methodologies for determining impact loads described in American Society of Civil Engineers (ASCE)

Standard 7-10 (ASCE, 2010) are acceptable (NRC, 2013a). Accordingly, ASCE 7-10 (ASCE, 2010) was used to calculate impact loads. Per ASCE 7-10 (ASCE, 2010), impact loads are those that result from logs and other objects striking buildings, structures, or paris thereof.

Per ASCE 7-10 (ASCE, 2010), a 1,000 lb object can be considered a reasonable average for waterborne debris. This represents a reasonable weight for trees, logs, and other large woody debris that are the most common forms of damaging debris nationwide. This weight corresponds to a log approximately 30 ft in length and just under 1 ft in diameter. This reference also notes that regional or local conditions should be Page 53 of69

NTTF Recommendation 2.I (Hazard Reevaluations): Flooding NextEra Energy- PBNP ENERCON March 6, 20I5 Excellence-Every proj ect. Every day. FPL-076-FHRPR-002, Revision 2 considered to determine the debris object weight. ASCE 7-IO (ASCE, 20IO) states that debris weight generally falls into three classes for coastal locations as follows:

I. In the Pacific Notthwest, a 4,000 lb debris weight is typical due to the large trees and logs in this area;

2. In other coastal areas where piers and large pilings are available locally, debris weights may range from I ,000 to 2,000 lbs; and

3. In other coastal areas where large logs and pilings are not expected, debris will likely be derived from failed decks, steps, and building components and will likely average less than 500 lbs.

Although there are no piers located near PBNP, a debris object weight (W) of 2,000 lbs was selected conservatively to determine the maximum impact load. To account for the larger weight, a slightly larger diameter of I.25 ft was used to calculate the resulting pressure. The I .25-ft diameter offsets the improbable length: a 1-ft diameter, 2,000 lb log would have a length of 60 ft.

ASCE 7-I 0 (ASCE, 20 10) presents a relationship for the magnitude of impact forces :

F = nWvCICoCvCBRmax Equation 4.I5 2gllt where:

F =impact force (lbs);

W =debris/projectile weight (lbs);

v =maximum flow velocity (ft/s);

g =gravitational acceleration (32.2 ft/s 2);

Llt =impact duration time (0.03 s [ASCE, 2010]);

C1 = impottance coefficient (1.3 [ASCE, 2010]);

Co =orientation coefficient (0.8 since direct impact is unlikely [ASCE, 2010]);

Cn =depth coefficient (1.0 [ASCE, 2010]);

CB =blockage coefficient (1.0 [ASCE, 2010]); and Rmax =maximum response ratio for impulsive loads (1.8 [ASCE, 2010]).

Impact pressures (pi, psf) were evaluated by dividing the impact force (F) by the cross-sectional area (A, ft 2) of the debris (i.e., Pi = FIA). A range of potential flow velocities was considered: I to 20 ft/s. Table 4.I6 summarizes the debris impact force and pressure for the entire flow velocity range. The maximum waterborne projectile impact force (F=I2I,76I lbs) and pressure (p,=99,220 psf) occurred for a flow velocity of20 ft/s.

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NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding p:* ENERCON NextEra Energy- PBNP March 6, 2015 Excellence-Every proj ect. Every day. FPL-076-FHRPR-002, Revision 2 5.0 COMPARISON WITH CURRENT DESIGN BASIS 5.1 Precipitation Flooding The CLB combined rainfall-snowmelt event for PBNP is 4.90 in. over 6 hr. The maximum WSELs produced by the CLB combined event are listed in Table 3 .I. The short duration of the maximum WSELs does not adversely affect SSCs.

The site-specific LIP evaluated in the FHR for PBNP is 12.8 in. over 1 hr. Four temporal distributions (first quartile, second quartile, third quartile, and fourth quartile) of the rainfall total were evaluated to detennine the sensitivity to precipitation timing. Further, two scenarios conesponding to potential site configurations were considered, as detailed in Section 4.1.7. The maximum flow depths and WSELs produced for the FHR LIP Scenario A and Scenario B events are listed in Table 4.2. In general, the third quartile and fowth quattile hyetographs resulted in the maximum flood elevations, with maximum flow depths up to +3.4 ft at the CWPH. The FHR WSELs and maximum flow depths exceed the CLB at the each POI.

5.2 Riverine Flooding The CLB and FHR concluded that PBNP is not affected by flooding from streams, rivers, or canals.

5.3 Dam Breaches and Failures The CLB and FHR concluded that PBNP is not affected by flooding from dam breaches or failures.

5.4 Storm Surge The CLB maximum PMSS WSEL is +589.72 ft-NA VD88 (+8.42 ft-Plant Datum), which is a result of the historical maximum Lake level of +583.0 ft-NA VD88 (+ 1.7 ft-Plant Datum), +0.17 ft of wind setup, and

+6.55 ft of wave runup on a vettical structure (i.e., +583.0 ft-NA VD88 + 0.17 ft + 6.55 ft =

+589.72 ft-NA VD88). The flood protection level is +590.3 ft-NA VD88 (+9.0 ft-Plant Datum), providing a minimum physical margin of +0.58 ft (i.e., +590.3 ft-NA VD88- [+589.72 ft-NA VD88] = +0.58 ft) .

The FHR maximum PMSS SWL was below the grade elevation at the CWPH and TB POls (Figure 4.5 for POI layout). As described in Section 4.4.1 0, the maximum PMSS SWL is a combination of the I 00-yr recurrence monthly average high Lake level (+583 .1 ft-NA VD88 [+ 1.8 ft-Plant Datum]) and a maximum storm surge of +4.5 ft. The WSEL at the maximum SWL, shown on Figure 4.25, is lower than plant grade at the CWPH and TB. Some wave runup is expected to overtop the riprap crest to a maximum temporary peak WSEL of+589.7 ft-NAVD88 (+8.4 ft-Plant Datum). Frictional losses and expansion of flow as the overtopped water volume travels landward are expected to reduce this maximum WSEL before reaching the nearest POI (CWPH Door 336 [Figure 4.5]). Thus, the FHR concluded that PBNP is not affected by flooding fi*om the PMSS event and that available physical margin increased to at least +0.6 ft.

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NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding NextEra Energy- PBNP ENERCON March 6, 2015 Excellence-Every project. Every day. FPL-076-FHRPR-002, Revision 2 5.5 Seiche The CLB proposes that a maximum seiche of 1 to 2 ft could occur. The FHR concluded that the maximum seiche to impact PBNP is 1.0 ft in amplitude. When considered with the I 00-yr recurrence monthly average high Lake level (+583.1 ft-NAVD88 [+1.8 ft-Plant Datum]), the maximum seiche SWL is

+584.1 ft-NA VD88 (+2.8 ft-Plant Datum). Thus, the CLB and FHR concluded that PBNP is not affected by flooding from a seiche event.

5.6 Tsunami Flooding A tsunami was not considered a meaningful hazard to PBNP per the CLB . The FHR determined that there were no earthquakes, landslides, or volcanic eruptions that would generate a tsunami in the Lake near PBNP. Therefore, the CLB and FHR concluded that PBNP is not affected by flooding from tsunamis.

5.7 Ice-Induced Flooding Ice-induced flooding and associated effects were not considered meaningful hazards at PBNP per the CLB .

The FHR indicates that ice jams have not been recorded in the watershed surrounding PBNP. Therefore, further consideration of ice-induced flooding (including the effects of frazil ice) was not required.

5.8 Channel Migration or Diversion Flooding The CLB and FHR Rep011 (FHRR) concluded that PBNP is not affected by flooding from channel migration or diversion since no streams of significance flow near PBNP.

5.9 Combined Events Flooding Combined flooding events related to storm surge and seiche flooding apply to PBNP and are addressed in Section 4.4 and Section 4.5, respectively. The relevant combined event comparisons are provided in Section 5.4 and Section 5.5 for storm surge and seiche flooding, respectively. All other combination events (e.g. , riverine PMF, dam breaches and failures, tsunami) were screened and do not affect PBNP.

5.10 Low Water Effects The CLB historical low water level was +576.5 ft-NA VD88 (-4.8 ft-Plant Datum). No additional wind setdown was considered in the CLB. The FHR considered an antecedent Lake level of +575.6 ft-NA VD88

(-5.6 ft-Plant Datum), which was the 100-yr recurrence monthly average Lake level. The maximum wind setdown was -3 .31 ft, producing the minimum SWL at the intake structure of +572.3 ft-NA VD88

(-9.0 ft-Plant Datum). The FHR low water level is below the CLB historical low water level.

A decreasing Lake level will manifest itself as a decreasing pump bay level. For any given Lake level, the pump bay level will vary based on the number of circulating water pumps that are running. Current PBNP procedures require operators to monitor pump bay level and to take actions, including securing some or all circulating water pumps as needed to assure pump bay level remains above +569.8 ft-NA VD88 Page 56 of69

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding v.*r ENE R C 0 N Excellence-Every project. Every day NextEra Energy- PBNP March 6, 2015 FPL-076-FHRPR-002, Revision 2

(-11.5 ft-Plant Datum). Remaining above that level assures operability limits of the service water system are not exceeded. If Lake level is below +572.3 ft-NA VD88 (-9.0 ft-Plant Datum), there remains sufficient margin in these existing operating procedures to assure pump bay level remains above +569.8 ft-NA VD88

(-11.5 ft-Plant Datum). Thus, there is no impact to PBNP based on the low water effects.

5.11 Hydrostatic, Hydrodynamic, and Sediment Loads Hydrostatic, hydrodynamic, and sediment loads were not considered in the CLB. However, the CLB did include airborne tornado missile design criteria for Class I structures. The FHR combined hydrostatic and hydrodynamic loads at the POls (Table 4.15) were bounded by the maximum tornado impact pressure by a significant margin for Class I structures. Non-Class I structures or other POls not considered in the FHR would need to be evaluated independently to determine the effect of LIP hydrostatic and hydrodynamic loading and/or wave runup forces on the southern side of the CWPH.

5.12 Debris and Waterborne Projectiles Flood debris and waterborne projectiles were not considered in the CLB. However, the CLB did include airborne tornado missile design criteria for Class I structures. The FHR waterborne projectile impact pressures (Table 4.16) were compared to the CLB tornado missiles, and found that sufficient margin existed for Class I structures, even at the highest range of expected flood velocities. Further, the PMSS SWL does not reach the CWPH POls (Figure 4.5) or further inland. Thus, waterborne projectiles will not impact any POI considered in the FHR.

5.13 Summary of Comparison The CLB-FHR comparisons discussed in Section 5.1 through Section 5.12 are summarized in Table 5.1.

The reevaluated LIP maximum flow depths exceed the CLB maximum flow depths. The reevaluated PMSS (with wave runup) maximum WSELs are below maximum CLB levels.

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NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding ENERCON NextEra Energy- PBNP March 6, 2015 Excellence-Every project. Every day FPL-076-FHRPR-002, Revision 2 6.0 INTERIM EVALUATION AND ACTIONS This section identifies interim actions to be taken before the Integrated Assessment (IA) is completed. It identifies the items to be addressed in the IA and the rationale for doing so.

6.1 Local Intense Precipitation The FHR LIP analysis is for a duration of one hour and the maximum depth of accumulated ponded water in the power block area is approximately +3.4 ft. Additional interim actions to address LIP flood heights that exceed CLB flood heights are not needed to assure PBNP's successful implementation of Flexible Coping Capability (FLEX) strategies.

Implementation of the site FLEX strategies requires equipment access via the Unit 1 and Unit 2 TB doors.

If those doors are unavailable for access, the door near the station heating boilers is used as an alternate.

The maximum water height at the TB doors from a LIP event is 2.6 ft and decreases rapidly, to less than one inch within three hours after the start of the LIP event (Figure 4.9). The maximum water height at the door near the heating boiler room is 2.2 ft, which decreases to approximately three inches within three hours after the start of the LIP event. FLEX strategies rely on these doors for access, but not until three hours after the stati of the evaluated Beyond Design Basis event. LIP water levels will not impact access at three hours into the event.

In addition to availability of the doors discussed above, implementation of the site FLEX strategies also relies on ce1iain installed station equipment. Equipment relied upon includes the Turbine Driven Auxiliary Feedwater (AFW) Pump, the Diesel Driven fire pump and the DC distribution system. The Turbine Driven AFW Pump is located in the AFW Pump Room. The Diesel Driven Fire Pump is located in the CWPH.

Two of the four safety related batteries at the station are located in the Vital Switchgear Room along with DC distribution busses DO 1 and D02 and three safety related battery chargers. Thus, the three areas with equipment relied upon for FLEX are the AFW Pump Room, the Vital Switchgear Room, and the CWPH.

If the TB rollup doors should fail during the LIP event, the external flood waters would enter the TB, resulting in 2.6 ft of flood height at the doors to the AFW Pump Room and the Vital Switchgear Room.

Calculation 2013-0021 Revision 1 addresses structural integrity of the doors to these rooms during a flood of up to 2 ft (NEE, 20 13). That calculation concludes that these doors have a large structural margin to withstand 2ft of water because the calculation contains several very large conservatisms (NEE, 2013). It is reasonable to conclude that the higher flood height of 2.6 ft (an increase of 30%) will not affect the conclusion of the calculation. Thus, there is reasonable assurance that these doors will remain structurally intact during and after a LIP event if the TB rollup doors are assumed to fail.

Regarding potential leakage past the doors to the AFW Pump Room and the Vital Switchgear Room, existing procedural requirements provide adequate protection during flooding at the site. Abnormal Operating Procedure (AOP) 13C Revision 38 is entered for a flood watch or warning or for actual significant water intrusion into the plant (NEE, 2015a). The AOP contains actions for operators to specifically monitor these two rooms and install sandbags to protect equipment in the two rooms (NEE, 2015a). Routine Maintenance Procedure (RMP) 9422 Revision 0 provides instruction for sandbag staging and placement (NEE, 2015b). The RMP requires an inventory of2,400 sandbags on site, and materials on hand to fill an additionall,OOO sandbags (NEE, 2015b). These procedural actions and sandbag inventories Page 58 of69

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding NextEra Energy- PBNP ENERCON March 6, 2015 Excellence-Every p roj ect. Every day FPL-076-FHRPR-002, Revision 2 are sufficient to control leakage past these room doors and assure equipment availability inside these rooms during the increased flood levels of a LIP event.

If the extemal doors in the CWPH should fail during the LIP event, water external to the building would flow into the CWPH and out the flood relief gates to the Lake. Calculation 2009-0008 Revision 2 addresses flood scenarios by establishing an acceptable flood height inside the CWPH, and then calculating the flow rate into the CWPH from a given flood height outside the CWPH (NEE, 20 14d). The calculation assumes all doors are fully open, and considers an external flood height of 2 ft (NEE, 20 14d). At that flood height, the calculation concludes that flood water will be sufficiently relieved through two of the eight flood relief gates without flooding critical equipment in the CWPH (NEE, 20 14d). A comparison can be made using this same method for the higher flood heights of 2.3 ft in the LIP event. In that case, the flood waters are relieved adequately through the flood relief gates and the internal flood height remains below the new Diesel Driven Fire Pump. Thus, it is concluded that during and after a LIP event the Diesel Driven Fire Pump will remain available for implementation of the FLEX strategies.

During high Lake level conditions, wave barriers 3.5 ft high are procedurally installed outside the CWPH rollup doors and sandbags are installed to seal the rollup doors. When the barriers are installed, the maximum LIP flood heights near the CWPH doors are projected to increase to 3.4 ft. It is reasonable to conclude that any leakage into the CWPH will be quickly relieved through the flood relief gates and no substantial water build up would occur inside the CWPH. It is therefore concluded that the Diesel Driven Fire Pump will remain available in a LIP event with the CWPH wave barriers in place.

In addition, further evaluations will be performed as part of the IA to assure protection of existing plant safety related equipment during a LIP event. Most of the ingress points into the plant for the higher flood levels projected from a LIP event are the same points of interest for a precipitation event flood defined in the CLB. Ingress points will be considered for specific corrective actions in the IA. Possible contributions by the yard drain system will also be considered along with preventive maintenance and inspection requirements to assure the system remains available as a drainage path. These and other specific corrective actions to protect safety-related equipment for the LIP event will be evaluated and identified in the IA report.

6.2 Riverine Flooding No interim measures are required since this hazard does not apply to PBNP. Therefore, this hazard will not be addressed in the IA.

6.3 Dam Breaches and Failures No interim measures are required since this hazard does not apply to PBNP. Therefore, this hazard will not be addressed in the IA.

6.4 Storm Surge No interim measures are required for this hazard since reevaluated PMSS levels would not adversely affect critical SSCs. The reevaluated PMSS levels are bounded by the CLB at the TB and CWPH POls.

Therefore, this hazard will not be addressed in the IA.

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,.. ENERCON Excellence- Every project. Every day.

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding NextEra Energy- PBNP March 6, 2015 FPL-076-FHRPR-002, Revision 2 6.5 Seiche No interim measures are required for this hazard since maximum reevaluated seiche levels are bounded by the reevaluated PMSS. Therefore, this hazard will not be addressed in the IA.

6.6 Tsunami No interim measures are required since tsunami flooding does not apply to PBNP. Therefore, this hazard will not be addressed in the IA.

6.7 Ice-Induced Flooding No interim measures are required since ice-induced flooding does not apply to PBNP. Therefore, this hazard will not be addressed in the IA.

6.8 Channel Migration or Diversion Flooding No interim measures are required since channel migration or diversion flooding does not apply to PBNP.

Therefore, this hazard will not be addressed in the IA.

6.9 Combined Events Flooding Combined flooding event comparisons related to storm surge and seiche flooding apply to PBNP and are addressed in Section 5.4 and Section 5.5, respectively. As discussed in Section 6.4 and Section 6.5, no interim measures are required for the storm surge or seiche hazards, respectively, and combined events will not be addressed in the IA.

6.10 Low Water Effects No interim measures are required since the existing site procedures bound the low water level effects.

6.11 Hydrostatic, Hydrodynamic, and Sediment Loads The loading from hydrostatic, hydrodynamic, and sediment loads on potentially impacted structures is bounded by design loading from tornado missiles for Class I structures at or above the minimum POI elevation evaluated . Therefore, this hazard will not be addressed in the IA for Class I structures. Other structures may be reevaluated as necessary. No interim actions are required.

6.12 Debris and Waterborne Projectiles The loading from debris and waterborne projectiles on potentially impacted structures is bounded by design loading from tornado missiles for Class I structures at or above the minimum POI elevation evaluated.

Therefore, this hazard will not be addressed in the IA for Class I structures. Other structures may be reevaluated as necessary. No interim actions are required.

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NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding F.:d ENERCON NextEra Energy - PBNP March 6, 2015 Excellence- Every p roject. Every day FPL-076-FHRPR-002, Revision 2 7.0 ADDITIONAL ACTIONS There are no additional actions identified as of the date of this submittal.

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NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding NextEra Energy- PBNP F.:dENERCON March 6, 2015 Excellence-Every proj eel. Every day. FPL-076-FHRPR-002, Revision 2

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NOAA (2014b), National Oceanic and Atmospheric Administration (NOAA), U.S. Department of Commerce, "Station 9087044, Calumet Harbor, Illinois," Available at http://tidesandcuJTents.noaa.gov/waterlevels.html? id=9087044, Accessed on June 6, 20 I 4.

NOAA (2014c), National Oceanic and Atmospheric Administration (NOAA), U.S. Depmtment of Commerce, "Station 9087068, Kewaunee, Wisconsin," Available at http://tidesandcurrents.noaa.gov/waterlevels.html? id=9087068, Accessed on June 6, 2014.

NOAA (2014d), National Oceanic and Atmospheric Administration (NOAA), U.S. Depmtment of Commerce, "Station 9087088, Menominee, Michigan" Available at http://tidesandcurrents.noaa.gov/waterlevels.html? id=9087088, Accessed on June 6, 2014.

Page 64 of69

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding NextEra Energy- PBNP March 6, 2015 Excellence-Every project. Everyday FPL-076-FHRPR-002, Revision 2 NOAA (2014e), National Oceanic and Atmospheric Administration (NOAA), U.S. Department of Commerce, "Station 9087096, P01i Inland, Michigan" Available at http://tidesandcurrents.noaa.gov/waterlevels.html? id=9087096, Accessed on June 6, 2014.

NOAA (2014f), National Oceanic and Atmospheric Administration (NOAA), U.S. Depmiment of Commerce, "Station 9087079, Green Bay, Wisconsin" Available at http://tidesandcurrents.noaa.gov/waterlevels.html? id=9087079, Accessed on June 6, 2014.

NOAA (2014g), National Oceanic and Atmospheric Administration (NOAA), U.S. Depmiment of Commerce, "Station 9087023, Ludington, Michigan" Available at http://tidesandcurrents.noaa.gov/waterlevels.html? id=9087023 , Accessed on June 6, 2014.

NOAA (2014h), National Oceanic and Atmospheric Administration (NOAA), U.S. Depmiment of Commerce, "Station 9087057, Milwaukee, Wisconsin" Available at http://tidesandcurrents.noaa.gov/waterlevels.html? id=9087057, Accessed on June 6, 2014.

NOAA (2014i), National Oceanic and Atmospheric Administration (NOAA), U.S. Depmiment of Commerce, "Station 9087072, Sturgeon Bay Canal, Wisconsin" Available at http://tidesandcurrents.noaa.gov/waterlevels.html? id=9087072, Accessed on June 6, 2014.

NOAA (2014j), National Oceanic and Atmospheric Administration (NOAA), U.S. Depmiment of Commerce, "Station 9087031, Holland, Michigan" Available at http://tidesandcurrents.noaa.gov/waterlevels.html? id=908703 I , Accessed on June 6, 2014.

NOAA (20141,:), National Oceanic and Atmospheric Administration (NOAA), U.S. Depmiment of Commerce, "Station 9087064, Manitowoc, Wisconsin" Available at http://tidesandcurrents.noaa.gov/waterlevels.html? id=9087064, Accessed on June 6, 2014.

NOAA (20141), National Oceanic and Atmospheric Administration (NOAA), U.S. Depmiment of Commerce, "Station 9087028, Muskegon, Michigan" A vail able at http://tidesandcurrents.noaa.gov/waterlevels.html? id=9087028, Accessed on June 6, 2014.

NOAA (2014m), National Oceanic and Atmospheric Administration (NOAA), U.S. Department of Commerce, "Station 9075080, Mackinaw City, Michigan" Available at http://tidesandcurrents.noaa.gov/waterlevels.html? id=9075080, Accessed on June 6, 2014.

NOAA (2014n), National Oceanic and Atmospheric Administration (NOAA), U.S. Department of Commerce, "Station 9075065, Alpena, Michigan" Available at http://tidesandcurrents.noaa.gov/waterlevels.html? id=9075065, Accessed on June 6, 2014.

NOAA (2014o), National Oceanic and Atmospheric Administration (NOAA), U.S. Depmiment of Commerce, "Station 9075035, Essexville, Michigan" Available at http://tidesandcurrents.noaa.gov/waterlevels.html? id=9075035 , Accessed on June 6, 2014.

NOAA (2014p), National Oceanic and Atmospheric Administration (NOAA), U.S. Department of Commerce, "Station 9075014, Harbor Beach, Michigan" Available at http://tidesandcurrents.noaa.gov/waterlevels.html? id=9075014, Accessed on June 6, 2014.

Page 65 of69

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding NextEra Energy- PBNP ENERCON March 6, 2015 Excellence- Every project. Every day FPL-076-FHRPR-002, Revision 2 NOAA (2014q), National Oceanic and Atmospheric Administration (NOAA), U.S. Depatiment of Commerce, "Station 9075002, Lakep01i, Michigan" Available at http://tidesandcurrents.noaa.gov/waterlevels.html? id=9075002, Accessed on June 6, 2014.

NOAA (2014r), National Oceanic and Atmospheric Administration (NOAA), U.S. Depatiment of Commerce, "Station 9014098, Foti Gratiot, Michigan" Available at http://tidesandcurrents.noaa.gov/waterlevels.html? id=9014098, Accessed on June 6, 2014.

NOAA (2014s), National Oceanic and Atmospheric Administration (NOAA), U.S. Depatiment of Commerce, "Station PNLM4," Available at http://www.ndbc.noaa.gov/station page.php?station=PNLM4, Accessed on June 9, 2014.

NOAA (2014t), National Oceanic and Atmospheric Administration (NOAA), U.S. Department of Commerce, "Station 45022," Available at http://www.ndbc.noaa.gov/station page.php?station=45022, Accessed on June 9, 2014.

NOAA (2014u), National Oceanic and Atmospheric Administration (NOAA), U.S. Department of Commerce, "Station 45002," Available at http://www.ndbc.noaa.gov/station page.php?station=45002, Accessed on June 9, 2014.

NOAA (2014v), National Oceanic and Atmospheric Administration (NOAA), U.S. Department of Commerce, "Station CBRW3," Available at http://www.ndbc.noaa.gov/station page.php?station=CBRW3 , Accessed on June 9, 2014.

NOAA (2014w), National Oceanic and Atmospheric Administration (NOAA), U.S. Depattment of Commerce, "Station 450 14," Available at http://www.ndbc.noaa.gov/station page.php?station=450 14, Accessed on June 9, 2014.

NOAA (2014x), National Oceanic and Atmospheric Administration (NOAA), U.S. Department of Commerce, "Station GBL W3," Available at http://www.ndbc.noaa.gov/station page.php?station=GBLW3 , Accessed on June 9, 2014.

NOAA (2014y), National Oceanic and Atmospheric Administration (NOAA), U.S. Depatiment of Commerce, "Station 45024," Available at http://www.ndbc.noaa.gov/station page.php?station=45024, Accessed on June 9, 2014.

NOAA (2014z), National Oceanic and Atmospheric Administration (NOAA), U.S. Depattment of Commerce, "Station 45161 ," Available at http://www.ndbc.noaa.gov/station page.php?station=45161 ,

Accessed on June 9, 2014.

NOAA (2014aa), National Oceanic and Atmospheric Administration (NOAA), U.S. Department of Commerce, "Station 450 13," Available at http://www.ndbc.noaa.gov/station page.php?station=450 13, Accessed on June 9, 2014.

NOAA (2014bb), National Oceanic and Atmospheric Administration (NOAA), U.S. Department of Commerce, "Station 45007," Available at http://www.ndbc.noaa.gov/station page.php?station=45007, Accessed on June 9, 2014.

Page 66 of69

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding ENERCON NextEra Energy- PBNP March 6, 2015 Excellence-Every project. Every day FPL-076-FHRPR-002, Revision 2 NOAA (2014cc), National Oceanic and Atmospheric Administration (NOAA), U.S. Department of Commerce, "Station 45170," Available at http://www.ndbc.noaa.gov/station page.php?station=45170, Accessed on June 9, 2014.

NOAA (2014dd), National Oceanic and Atmospheric Administration (NOAA), U.S. Depmtment of Commerce, "Station BHRI3," Available at http://www.ndbc.noaa.gov/station page.php?station=BHRI3 ,

Accessed on June 9, 2014.

NOAA (2014ee), National Oceanic and Atmospheric Administration (NOAA), U.S. Department of Commerce, "Station 45003 ," Available at http://www.ndbc.noaa.gov/station page.php?station=45003 ,

Accessed on June 9, 2014.

NOAA (2014ff), National Oceanic and Atmospheric Administration (NOAA), U.S . Department of Commerce, "Station MACM4," Available at http://www.ndbc.noaa.gov/station page.php?station=MACM4, Accessed on June 9, 2014.

NOAA (2014gg), National Oceanic and Atmospheric Administration (NOAA), U.S. Department of Commerce, "Station 45008," Available at http://www.ndbc.noaa.gov/station page.php?station=45008, Accessed on June 9, 2014.

NOAA (2014hh), National Oceanic and Atmospheric Administration (NOAA), U.S. Department of Commerce, "Natural Hazards Data, Images and Education," Available at http://www.ngdc.noaa.gov/hazard/hazards.shtml, Accessed on February 28, 2014.

NOAA (2014ii), National Oceanic and Atmospheric Administration (NOAA), National Climatic Data Center, U.S. Depmtment of Commerce, "National Climatic Data Center," Available at http://ncdc.noaa.gov/sotc/national/2014/2/supplemental/page-6, Accessed on March 7, 2014.

NOAA (2014jj), National Oceanic and Atmospheric Administration (NOAA), Emth System Research Laboratory, Physical Science Division, "20 111 Century Reanalysis (V2) Data Composites," Available at http://www.esrl.noaa.gov/psd/data/composites/subdaily 20thc/, Accessed on June 30, 2014.

NOAA (2014ld{), National Oceanic and Atmospheric Administration (NOAA), Emth System Research Laboratory, Physical Science Division, "6-Hourly NCEP/NCAR Reanalysis Data Composites," Available at http://www.esrl.noaa.gov/psd/data/composites/hour/, Accessed on June 30, 2014.

NOAA (201411), National Oceanic and Atmospheric Administration (NOAA), Emth System Research Laboratory, Physical Science Division, "3-Hourly NCEP North American Regional Reanalysis (NARR)

Composites," Available at http://www.esrl.noaa.gov/psd/cgi -bin/data/narr/plothour.pl., Accessed on June 30, 2014.

NRC (1977), U.S. Nuclear Regulatory Commission (NRC), "Design Basis Floods for Nuclear Power Plants," Regulatory Guide 1.59, Revision 2, Washington D.C., August 1977, with errata dated June 30, 1980.

NRC (1978), U.S. Nuclear Regulatory Commission (NRC), "Standard Format and Content of Safety Analysis Reports for Nuclear Power Plants," Regulatory Guide 1.70, Revision 3, Washington, D.C., 1978.

Page 67 of69

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding NextEra Energy- PBNP ENERCON March 6, 2015 Excellence-Every project. Every day FPL-076-FHRPR-002, Revision 2 NRC (2007), U.S. Nuclear Regulatory Commission (NRC), "Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: L WR Edition," NUREG-0800, Washington, D.C.,

March 2007.

NRC (2009), U.S . Nuclear Regulatmy Commission (NRC), "Tsunami Hazard Assessment at Nuclear Power Plant Sites in the United States of America Final Repmt," NUREG/CR-6966 PNNL-17397, Washington, D.C., March 2009.

NRC (2011), U.S. Nuclear Regulatory Commission (NRC), "Design-Basis Flood Estimation for Site Characterization at Nuclear Power Plants in the United States of America," NUREG/CR-7046, Washington, D.C., November 2011.

NRC (2012), U.S. Nuclear Regulatory Commission (NRC), "Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Recommendations 2.1, 2.3 , and 9.3, of the Near-term Task Force Review oflnsights from the Fukushima Dai-ichi Accident," Washington, D.C., March 12, 2012.

NRC (2013a), U.S. Nuclear Regulatory Commission (NRC), "Guidance for Performing a Tsunami, Surge, or Seiche Hazard Assessment," JLD-ISG-2012-06, Revision 0, Washington, D.C., January 4, 2013.

NRC (2013b), U.S. Nuclear Regulatory Commission (NRC) "Guidance for Assessment of Flooding Hazards Due to Dam Failure," JLD-ISG-2013-01 , Revision 0, July 29, 2013 .

Riedel et al. (1956), Reidel, J.T., J.F. Appleby, and R.W. Schloemer, Weather Bureau, U.S. Department of Commerce, "Seasonal Variation of the Probable Maximum Precipitation East of the l05 1h Meridian for Areas from 10 to 1000 Square Miles and Durations of 6, 12, 24, and 48 Hours," Hydrometeorological Repmt (HMR) No. 33 , Washington, D.C., 1956.

S&L (1967), Sargent and Lundy Engineers (S&L), "Point Beach Nuclear Plant, Wisconsin Michigan Power Company, Maximum Deep Water Waves & Beach Run-up at Point Beach," Janumy 14, 1967.

Schreiner and Riedel (1978), Schreiner, L.C. and J.T. Riedel, National Weather Service (NWS), National Oceanic and Atmospheric Administration (NOAA), U.S. Department of Commerce, "Probable Maximum Precipitation Estimates, United States East of the 105 1h Meridian," Hydrometeorological Repmt (HMR)

No. 51 , Washington, D.C., 1978.

Schwab and Morton (1984), Schwab, D. and J. Morton, "Estimation of Overlake Wind Speed from Overland Wind Speed: A Comparison of Three Methods." Journal of Great Lakes Resources, 10, pp. 68-72.

SCO (2012), Wisconsin State Cartographer's Office (SCO), " Wisconsin Coordinate Reference Systems,"

Second Edition, Madison, Wisconsin, 2012.

Street et al. (1996), Street, R.L. , G.Z. Watters, and J.K. Vennmd, "Elementary Fluid Mechanics,"

7th Edition, John Wiley & Sons, 784 p., 1996.

USACE (1991), U.S. Army Corps of Engineers (USACE), Nmth Central Division, "Great Lakes Levels, International Great Lakes Datum," Update Letter No. 76, November 4, 1991 .

USACE (2008), U.S. Army Corps of Engineers (USACE), "Coastal Engineering Manual,"

EM 1110-2-1100.

Page 68 of69

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding P: .r E N E R C 0 N NextEra Energy - PBNP March 6, 2015 Excellence-Every project. Every day. FPL-076-FHRPR-002, Revision 2 USACE (2012), U.S. Army Corps of Engineers (USACE), "Statistical Analysis and Storm Sampling Approach for Lakes Michigan and St. Clair, Great Lakes Coastal Flood Study," 2012 Federal Interagency Initiative.

USACE (2014), U.S. Army Corps of Engineers (USACE), "National Ice Jam Database, Bulletin and Survey," Available at http://icejams.crrel.usace.army.mil/, Accessed on March 7, 2014.

USGS (2011), U.S. Geological Survey (USGS), "113 -Arc Second National Elevation Dataset," National Elevation Dataset grid n45w088_1, United States Geological Survey National View Website," Available at http://viewer.nationalmap.gov/viewer, Accessed on December 1, 2014.

USGS (2014a), U.S. Geological Survey (USGS), "Landslide Hazards Program," Available at http://landslides.usgs.gov, Accessed on March 4, 2014.

USGS (2014b), U.S. Geological Survey (USGS), "Landslide Monitoring," Available at http://landslides.usgs.gov/monitoring, Accessed on March 4, 2014.

USNIC (2014), U.S. National Ice Center (USNIC), "National Ice Center," Available at http://www.natice.noaa.gov/products/great lakes.html , Accessed on March 7, 2014.

Walstra and Koster (2006), Walstra, D.J.R. and L. Koster, Delft Hydraulics, "Benchmarking Database for Delft3D," November 2006.

Wang et al. (2012), Wang, J., R. Assel, S. Waltersheid, A. Clites, and X. Bai, "Great Lakes Ice Climatology Update: Winter 2006-2011 Description of the Digital Ice Cover Dataset," National Oceanic and Atmospheric Administration Technical Memorandum GLERL-155.

WMO (2009), World Meteorological Organization (WMO), "Manual for Estimation of Probable Maximum Precipitation," Operational Hydrology Report No. 1045, Geneva, 2009.

Wuest and Lorke (2003), Wuest, A. and A. Lorke, "Small-scale Hydrodynamics in Lakes," Annual Review ofFluid Mechanics 35, pp. 373-412.

Page 69 of69

NTTF Recommendation 2.1 (Hazard Reevaluations) : Flooding NextEra Energy - PBNP ENERCON March 6, 2015 Excellence-Every project. Every day. FPL-076-FHRPR-002, Revision 2 Table 2.1- Vertical Datum Conversions Datum Input (Conversion from)

Datum Output (Conversion to) ft- ft- ft- ft-Plant IGLDSS IGLD85 NAVD88 Datum ft-IGLDSS 0.0 -0.7 - 1.1 +580.2 ft-IGLD85 +0.7 0.0 -0.4 +580.9 ft-NAVD88 + 1.1 +0.4 0.0 +581.3 ft-Plant Datum -580.2 -580.9 -581.3 0.0 Sample Conversions: 600.0 ft-NA VD88 = 18.7 ft-Plant Datum (i.e., 600.0 ft- 581.3 ft = 18.7 ft) 599.6 ft-IGLD85 = 600.0 ft-NA VD88 (i.e., 599.6 ft + 0.4 ft = 600.0 ft)

References:

NEE, 2010; NEE, 2012c

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding NextEra Energy - PBNP ENERCON March 6, 2015 Excellence-Every project. Every day FPL-076-FHRPR-002, Revision 2 Table 3.1- CLB Precipitation Flood Event Maximum WSELs at POls Maximum WSEL POI (Door Maximum Flow Building Location) Depth (ft) 5 (ft-Piant Datum) (ft-NAVD88)

~ NIA +8.1 +589.4 2 0.4 +8.1 +589.4 Turbine 4 0.2 +8.1 +589.4 Building 11 0.3 +8.2 +589.5 13 0.1 +8.2 +589.5 600 NIA +26.9 +608.2 601 0.1 +27.2 +608.5 Diesel N/A 602 +27.6 +608.9 Generator 603 N/A +27.3 +608 .6 604 0.2 +27.6 +608.9 151 0.2 +26.1 +607.4 152 0.3 +26 .2 +607.5 154 0.4 +26.3 +607.6 Unit 1 & N/A +607.2 209 +25.9 Unit2 210 0.1 +26.1 +607.4 231 1.0 +26.6 +607.9 232 1.0 +26.6 +607.9 310 0.1 +25.7 +607.0 311 NIA +25.7 +607.0 Service N/A 312 +25 .8 +607.1 Building 313 0.1 +25.9 +607.2 314 0.1 +25.9 +607.2 336 0.7 +7.6 +588.9 338 0.7 +7.7 +589.0 CWPH 339 0.8 +7.8 +589.1 340 0.6 +7.6 +588.9

References:

NEE, 2014b 5 N/A for maximum flow depth indicates a maximum flow depth <0.1 ft, not necessarily 0.0 ft.

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding NextEra Energy- PBNP ENERCON March 6, 2015 Excellence- Every project. Every day FPL-076-FHRPR-002, Revision 2 Table 3.2- CLB Wave Run up Vertical Height Wind Maximum Lake Level Total WSEL Type of Surface6 of Run up (ft) Setup (ft) (ft-Piant Datum) (ft-Piant Datum) 1:1% Riprap Slope +5.38 +0.17 +1.7 +7.25 Vertical Structure +6.55 +0.17 +1.7 +8.42

References:

NEE, 2014b 6 Slopes are repmied as ve1tical (V) to horizontal (H), V:H.

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding ENERCON NextEra Energy- PBNP March 6, 2015 Excellence-Every project. Every day FPL-076-FHRPR-002, Revision 2 Table 4.1- Site-Specific Subhourly PBNP LIP Precipitation Depths Time (min) Precipitation Depths (in) 60 12.8 30 9.9 15 6.9 5 4.4 References : None

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding ENERCON NextEra Energy- PBNP March 6, 2015 Excellence- Every project. Every day. FPL-076-FHRPR-002, Revision 2 Table 4.2 -Site-Specific LIP Scenario A and Scenario B Maximum Flow Depths and WSELs at POls Scenario A Scenario B '

]>OJ Maximum Maximum WSEL Maximum Maximum WSEL Building (Door Location) Flow Depth Flow Depth, (ft) (ft-Plant (ft) (ft-Piant (ft-NAVD88) (ft-NAVD88)

Datum) Datum) 1 1.9 +9.9 +591.2 2.5 +10.5 +591.8 2 1.9 +9.9 +591.2 2.5 +10.5 +591.8 Turbine 4 1.9 +9.9 +591.2 2.5 +10 .5 +591.8 Building 11 2.1 +10.1 +591.4 2.6 +10 .6 +591.9 13 2.1 +10 .1 +591.4 2.6 +10.6 +591.9 600 0.2 +26.4 +607.7 0.2 +26.4 +607.7 601 0.1 +28 .0 +609.3 0.1 +28.0 +609.3 Diesel 602 0.5 +28.0 +609.3 0.5 +28.0 +609.3 Generator 603 0.3 +27.8 +609.1 0.3 +27.8 +609.1 604 0.7 +28.0 +609.3 0.7 +28.0 +609.3 151 1.9 +27.7 +609.0 1.9 +27 .7 +609.0 152 2.1 +28.0 +609.3 2.1 +28.0 +609.3 154 2.3 +28.2 +609.5 2.3 +28.2 +609.5 159 2.4 +28.3 +609.6 2.4 +28.3 +609.6 Unit 1 &

167 2.2 +28.2 +609.5 2.2 +28.2 +609.5 Unit2 209 1.0 +27.1 +608.4 1.0 +27.0 +608.3 210 1.9 +27 .7 +609.0 1.9 +27.8 +609.1 231 2.3 +28.2 +609.5 2.3 +28.2 +609.5 232 2.5 +28 .2 +609.5 2.5 +28.2 +609.5 310 1.0 +26.4 +607.7 1.0 +26.4 +607.7 311 0.9 +26.7 +608.0 0.9 +26.7 +608.0 Service 312 0.9 +26 .8 +608.1 0.9 +26.8 +608 .1 Building 313 1.2 +27 .0 +608 .3 1.2 +27.0 +608.3 314 1.1 +27.1 +608.4 1.1 +27.0 +608.3 336 2.1 +9.2 +590.5 2.5 +9.8 +591.1 338 2.8 +9.8 +591.1 3.4 +10.5 +591.8 CWPH 339 2.8 +10.0 +591 .3 3.3 +10.5 +591.8 340 2.3 +9.6 +590.9 2.6 +9.9 +591.2 G501 2.1 +27.9 +609.2 2.1 +27.9 +609.2 G502 2.1 +27.9 +609.2 2.1 +27.9 +609.2 GS 2.2 +28.0 +609.3 2.2 +28.0 +609.3 G503 Building G504 2.0 +27.9 +609.2 2.0 +27.9 +609.2 GSOS 1.8 +27.7 +609.0 1.8 +27.7 +609.0

References:

None

NTTF Recommendation 2. I (Hazard Reevaluations): Flooding NextEra Energy - PBNP ENERCON March 6, 2015 Excellence-Every project. Every day. FPL-076-FHRPR-002, Revision 2 Table 4.3- Summary of Lake Level Frequency Analysis Results 100-Year Recurrence Monthly 100-Year Recurrence Monthly Average High Lake Level at PBNP Average Low Lake Level at PBNP (ft-NAVD88) (ft-Plant Datum) (ft-NAVD88) (ft-Plant Datum)

Kewaunee, WI7 +583.1 +1.8 +575.6 -5.7 Milwaukee, WI8 +583.1 +1.8 +575.9 -5.4

References:

ESRI, 2012; NOAA, 2014c; NOAA, 2014h 7

Kewaunee station is approximately 12.7 miles from PBNP, measured using ArcGIS (ESRI, 20 12).

8 Milwaukee station is approximately 90.1 miles from PBNP, measured using ArcGIS (ESRI, 20 12).

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding NextEra Energy- PBNP ENERCON March 6, 2015 Excellence- Every project. Every day FPL-076-FHRPR-002, Revision 2 Table 4.4- Potential PMWS Scenarios Scenario Event (Date- Approach Direction) 1 January 18-21, 1907- Southwest 2 January 18-21, 1907- West 3 March 21-22, 1913- Southwest 4 March 21-22, 1913- West 5 November 7-10, 1913- North 6 November 7-10, 1913- Northwest 7 October 19-21, 1916- Northeast 8 October 20-24, 1929- North 9 October 10-11, 1949- South 10 December 24-26, 1965- Northwest 11 January 10-12, 1975 - Northwest 12 January 10-12, 1975- South 13 January 10-12, 1975- Southeast 14 January 25-28, 1978- North 15 January 25-28, 1978- Southwest 16 April 3-4, 1982- Nmiheast 17 Apri13-4, 1982- Nmihwest 18 January 23-24, 1982- East 19 January 23-24, 1982- Southeast 20 January 4-5, 1982- Nmiheast 21 December 1-2, 1985- Northeast 22 March 4-5, 1985- East 23 December 15-17, 1987-East 24 December 15-17, 1987- Southeast 25 September 22-24, 1989- Nmih 26 September 22-24, 1989- Nmiheast 27 December 3-4, 1990- East 28 December 3-4, 1990- Nmihwest 29 November 9-12, 1998- South 30 November 9-12, 1998- Southeast 31 November 9-12, 1998- Southwest 32 March 9-11, 2002 - Nmihwest 33 March 9-11, 2002 - West 34 November 11-14, 2003 - Nmihwest 35 November 11-14, 2003- South 36 November 11-14, 2003 - Southwest 37 December 27-29, 2008- South 38 December 27-29, 2008- Southwest 39 December 27-29, 2008- West 40 October 27-28, 2010- Nmihwest 41 October 27-28, 2010- Southwest 42 October 27-28, 2010 - West 43 October 29-November 1, 2012- Nmih 44 October 29-November 1, 2012- Northeast 45 October 29-November 1, 2012- Northwest

References:

None

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding F.)J ENERCON NextEra Energy- PBNP March 6, 2015 Excellence-Every project. Every day.

FPL-076-FHRPR-002, Revision 2 Table 4.5- NOAA Tide and Water Level Stations Considered for Calibration and Validation Station ID Latitude Longitude 1985 Event 1990 Event 2010 Event 9087044 41.73 -87.54 60 minute 60 minute 6 minute 9

9087068 44.46 -87.50 60 minute unused data 6 minute 9087088 45 .10 -87.59 no data no data 6 minute 9087096 45.97 -85 .87 60 minute 60 minute 6 minute 9087079 44.54 -88.01 60 minute 60 minute 6 minute 9087023 43 .95 -86.44 60 minute 60 minute 6 minute 9087057 43 .00 -87.89 60 minute 60 minute 6 minute 9087072 44.80 -87.31 60 minute 60 minute 6 minute 9087031 42.77 -86 .20 60 minute 60 minute 6 minute 9087064 44.09 -87.65 no data no data no data 9087028 43.23 -86.34 no data no data no data 9075080 45.78 -84.73 60 minute 60 minute 6-minute 9075065 45.06 -83.43 no data no data 6-minute 9075035 43.64 -83 .85 60 minute 60 minute 6 minute 9075014 43.85 -82.64 60 minute 60 minute 6 minute 9075002 43 .14 -82.49 60 minute 60 minute 6 minute 9014098 43.01 -82.42 60 minute 60 minute 6 minute References : NOAA, 2014b through NOAA, 2014r 9

"unused data" indicated that greater than 50% of the water level observations during the event were rejected by NOAA (i.e. ,

data flag = '999').

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding NextEra Energy- PBNP ENERCON March 6, 2015 Excellence-Every proj ect. Every day. FPL-076-FHRPR-002, Revision 2 Table 4.6- NOAA Buoy Stations Considered for Calibration and Validation Station ID Depth(m) Latitude Longitude 1985 Event 1990 Event 2010 Event PNLM4 - 45.97 -85.87 No No Yes 45022 2.98 45.40 -85.09 No No Yes 45002 173 45.34 -86.41 No unused data 10 Yes CBRW3 - 45.20 -87.36 No No Yes 45014 13 44.80 -87.76 No No No GBLW3 - 44.65 -87.90 No No unused data6 45024 - 43.98 -86.56 No No No 45161 25 43.18 -86.36 No No No 45013 20 43.10 -87.85 No No No 45007 160 42 .67 -87.03 unused data6 No Yes 45170 19 41.76 -86.97 No No No BHRI3 - 41.65 -87.15 No No unused data 6 45003 134.7 45.36 -82.90 No No Yes MACM4 - 45.78 -84.72 No No unused data6 45008 54.3 44.28 -82.42 unused data6 No Yes

References:

NOAA, 2014s through NOAA, 2014gg 10 "unused data" indicated that greater than 50% of the water level observations during the event were rejected by the following rejection criteria:

• All data with data flag= '999' were removed fi*om consideration.

• All wave direction values 2: 360 degrees were removed from consideration.

• All Hs 2: 10 m were removed from consideration.

• All periods of repeating Hs were removed from consideration.

• All peak wave period values (1) 2: 10 s were removed fi*om consideration.

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding NextEra Energy- PBNP ENERCON March 6, 2015 Excellence-Every proj ect. Every day.

FPL-076-FHRPR-002, Revision 2 Table 4. 7- Delft3D-FLOW Storm Surge Calibration Simulations Manning's n Air Calibration Wind Drag RMSE NSE Coefficient density (m)11 Notes Simulation Formulation (dimensionless)

(dimensionless) (kg/m 3) 1 Del tares (20 14a) 0.02 I 0.092 0.613 -

2 Jensen eta!. (2012) 0.02 1 0.100 0.538 -

3 Liu (1965) 0.02 1 0.089 0.634 -

Wuest and Larke 4

(2003) 0.02 1 0.098 0.559 -

5 Liu (1965) 0.01 1 0.100 0.543 -

6 Liu (1965) 0.03 1 0.086 0.661 -

7 Liu (1965) 0.04 1 0.086 0.663 -

Extended 9 Liu (1965) 0.04 1.28 0.096 0.559 time series References : Liu, 1965; Wuest and Lorke, 2013; Jensen eta!., 2012; Deltares, 2014a 11 RMSE and NSE are calculated for water surface elevation simulated and observed data across all available sites.

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding I ENERCON NextEra Energy - PBNP March 6, 2015 Excelle nce-Every project. Every day.

FPL-076-FHRPR-002, Revision 2 Table 4.8- Delft3D Final Calibrated Parameter Values Calibrated Parameter Value Wave scheme Stationary Wind drag coefficient Liu (1965)

Manning's roughness 0.04 CJQN 0.067

"=

'Y (Depth-induced breaking) 0.55 References : Liu, 1965

NTTF Recommendation 2.1 (Hazard Reevaluations) : Flooding ENERCON NextEra Energy- PBNP March 6, 2015 Excellence-Every proj ect. Every day.

FPL-076-FHRPR-002, Revision 2 Table 4.9- Summary of Parameters for Delft3D-FLOW Model Grid Lal{e Michigan Lake Huron Strait of Flow Grid 2 Reference Parmeters Flow Grid 1 Flow Grid2 Mackinac Grid Type Rectangular Rectangular Rectangular Rectangular -

Grid Cell Size 2km 2km 0.66 km 0.285 km -

Grid Cells M 129 196 43 176 -

Direction Grid Cells N Direction 268 183 94 183 -

Reference Model datum Model datum Model datum Model datum -

Datum Cartesian Cartesian Cmiesian Cartesian GCS Nmih GCS Nmih GCS North GCS North Coordinate System American 1927 American I 927 American 1927 American I927 -

NAD I927 NAD I927 NAD 1927 NAD I927 Albers projection Albers projection Albers projection Albers projection Numbe~r of I I 1 I -

Layers Thin Dams None Specified None Specified None Specified None Specified -

None Specified None Specified None Specified

~

D*)'Points None Specified -

Time Step - 0.25 min 0.25 min 0.25 min 0.25 min -

Wind and Wind and Wind and Wind and Physical Pressure Forcing; Pressure Forcing; Pressure Forcing; Pressure Forcing; Del tares Processes "'-

Online Wave Online Wave Online Wave Online Wave (20I4a)

Modeled Interactions Interactions Interactions Interactions Initial Condition Uniform at 0 m Uniform at 0 m Uniform at 0 m Uniform at 0 m -

Water Level Open

~

Boundary N/A N/A N/A N/A -

Conditions Boundary Conditions NIA N/A N/A N/A -

Type Number of Boundary 0 0 0 0 -

Conditions Open Boundary N/A N/A N/A N/A -

Condition Pressure Open Boundal)'

Condition N/A N/A N/A N/A -

Refle~;tion Coefficient

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding NextEra Energy- PBNP ENERCON March 6, 2015 Excellence-Every project. Every day. FPL-076-FHRPR-002, Revision 2 Grid Lake Michigan Lake Huron Strait of Flow Grid 2 Reference Parmeters Flow Grid 1 Flow Grid 2 Maclrinac Gravitational NOAA 9.81 m/s 2 9.81 m/s 2 9.81 m/s2 9.81 m/s 2 Acceleration (1986)

Street et al.

Water Density 1000 kg/m 3 1000 kg/m 3 1000 kg/m 3 1000 kg/m 3 (1996)

Street et al.

Air Density 1.28 kg/m 3 1.28 kg/m 3 1.28 kg/m 3 1.28 kg/m 3 (1996)

A- 0.00063 at A- 0.00063 at A- 0.00063 at A- 0.00063 at 0 m/s 0 m/s 0 m/s 0 m/s Wind Drag B- 0.0025 at B -0.0025 at B- 0.0025 at B- 0.0025 at Del tares Coefficient 25 m/s 25 m/s 25 m/s 25 m/s (2014a)

Breakpoints C- 0.0025 at C- 0.0025 at C- 0.0025 at C- 0.0025 at

~

100 m/s 100 m/s 100 m/s 100 m/s Spatially varied Spatially varied Spatially varied Spatially varied Bottom Manning's n Manning's n Marming's n Manning's n -

Roughness (0.02 uniform) (0.02 uniform) (0.02 uniform) (0.02 uniform)

Stress Formulation Del tares Fredsoe Fredsoe Fredsoe Fredsoe due to Wave (2014a)

Forces WaJI Deltares Roughness Slip Free Slip Free Slip Free Slip Free Slip (2014a)

Condition Eddy Vjscosity Uniform at 1 Uniform at 1 Uniform at 1 Uniform at 1 Deltares I Diffusivity m2/s m2/s m2/s m2/s (2014a)

Space Varying Space Varying Space Varying Space Varying Wind Wind and Wind and Wind and Wind and -

Pressure Pressure Pressure Pressure Drying and Grid Cell Centers Grid Cell Centers Grid Cell Centers Grid Cell Centers Flooding and Faces and Faces and Faces and Faces Check at Depth Grid Cell Grid Cell Grid Cell Grid Cell Specified at Corners Corners Corners Corners Depth at Grid Maximum Maximum Maximum Maximum -

Cell Centers Depth at Grid Mean Mean Mean Mean -

Cell Faces Advection Scheme for Cyclic Cyclic Cyclic Cyclic -

Momentum Threshold 0.1 m 0.1 m 0.1 m 0.1 m -

Depth Marginal None None None None -

Depth Smoothing 60 min 60 min 60 min 60 min -

Time

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding r.* ENERCON Excellence- Every project. Every day.

NextEra Energy- PBNP March 6, 2015 FPL-076-FHRPR-002, Revision 2 Grid Lal<e Michigan Lake Huron Strait of Flow Grid 2 Reference Parmeters Flow Grid 1 Flow Grid 2 Mackinac Threshold Depth for N/A NIA N/A N/A -

Critical Flow Limiter

References:

NOAA, 1986; Street eta!., 1996; Del tares, 20 14a

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding 1\:d ENERCON NextEra Energy- PBNP March 6, 2015 Excellence-Every project. Every day.

FPL-076-FHRPR-002, Revision 2 Table 4.10- Summary of Parameter for Delft3D-WAVE Model Grid Parmeters Wave Grid 1 Reference Grid Type Rectangular -

Grid Cell Size 2km -

Grid Cells MDirection 335 -

Grid Cells N Direction 286 -

Reference Datum Model Datum -

Cartesian Coordinate System GCS North American 1927 NAD 1927 Albers projection Spec. Res. N Directions 36 -

Lowest Freq. 0.01 Hz -

Highest Freq. 1Hz -

N bins 24 -

BoundaryHs N/A -

Boundary- Peal{ p~riod N/A -

Boundary (nautical) N/A -

Boundary -Directional Spreading N/A -

Gravity 9.81 m/s2 NOAA (1986)

Water density 1000 kg/m 3 Street et al. ( 1996)

North w.r.t. x-axis 90 (deg) -

Minimum depth 0.05 (m) -

Generation Mode 3'd generation Del tares (20 14b)

Depth-induced breaking alpha 1 Deltares (2014b)

Depth-induced breaking gamma 0.73 Del tares (20 14b)

Non-linear triad interactions alpha 0.1 Del tares (20 14b)

Non-linear triad interactions beta 2.2 Deltares (20 14b)

Bottom friction type JONSWAP Del tares (20 14b)

JONSWAP Coefficient 0.067 m2 I s3 Del tares (20 14b)

Wind Growth Activated Del tares (20 14b)

Whitecapping Komen et al. Del tares (20 14b)

Wave Propagation- Refraction Activated Deltares (20 14b)

Wave Propagation- Frequency Shift Activated Del tares (20 14b)

Directional space scheme 0.5 -

Frequency space scheme 0.5 -

Relative Change Hs-TmOl 0.1 -

Percentage wet criteria 98% -

Relative Change Hs 0.1 -

Relative Change TMOl 0.1 -

N Iterations 15 -

References:

NOAA, 1986; Street eta!., 1996; De !tares, 20 14b

,.. ENERCON Excellence- Every project. Every day NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding NextEra Energy- PBNP March 6, 2015 FPL-076-FHRPR-002, Revision 2 Table 4.11 -Peak WSEL from Synoptic Screening Events WSEL WSEL Hs (ft-Scenario Approach h (ft) T (s) R (ft) (ft-(ft) Plant NAVD88)

Datum) 1 1 11.0 2.9 4.6 1.4 +3 .5 +584.8 1 2 9.4 2.7 4.5 1.2 +3.2 +584.5 2 1 11.0 2.1 3.4 0.9 +2.9 +584.2 2 2 9.4 2.0 3.3 0.8 +2 .7 +584.0 3 1 11.3 . 4.3 6.0 2.5 +4.8 +586.1 3 2 9.7 3.8 5.9 2.0 +4.3 +585.6 4 1 11.3 4.3 5.9 2.5 +4.9 +586 .2 4 2 10.0 4.4 6.0 2.6 +5.2 +586.5 5 1 11.1 2.7 4.4 1.4 +3 .6 +584.9 5 2 9.5 2.6 4.4 1.2 +3.3 +584.6 6 1 10.9 1.5 3.6 0.7 +2 .6 +583.9 6 2 8.8 3.0 5.1 1.1 +2.6 +583.9 7 1 10.9 2.3 3.9 1.0 +3 .0 +584.3 7 2 9.3 2.6 3.6 1.0 +3.0 +584.3 8 1 10.7 4.3 5.1 1.6 +3.3 +584.6 8 2 9.1 4.3 5.2 1.7 +3.4 +584.7 9 1 11.7 3.9 5.9 3.0 +5.7 +587.0 9 2 10.1 4.0 6.3 2.8 +5 .5 +586.8 10 1 10.9 4.3 5.4 1.8 +3.7 +585.0 10 2 9.3 4.3 5.4 1.9 +3.8 +585.1 11 1 10.5 3.9 5.1 1.4 +3.0 +584.3 11 2 8.9 3.9 5.1 1.5 +3.0 +584.3 12 1 11.8 4.1 5.8 3.1 +6.0 +587.3 12 2 10.2 4.0 6.0 2.8 +5.5 +586.8 13 1 11.6 4.3 7.1 3.3 +6.0 +587.3 13 2 10.2 4.1 8.2 3.4 +6.3 +587.6 14 1 10.8 3.9 7.9 2.1 +3.9 +585 .2 14 2 9.2 3.7 7.8 2.0 +3. 8 +585.1 15 1 10.8 3.9 7.9 2.1 +3 .9 +585.2 15 2 9.2 3.7 7.8 2.0 +3 .8 +585 .1 16 1 11.0 4.0 7.0 2.1 +4.1 +585.4 16 2 9.4 3.7 7.0 2.0 +4.0 +585.3 17 1 10.7 3.6 4.4 1.3 +3.1 +584.4 17 2 9.1 3.4 4.7 1.4 +3 .1 +584.4 18 1 10.8 4.1 4.6 1.5 +3 .3 +584.6 18 2 9.3 5.0 6.4 1.5 +3.3 +584.6 19 1 11.1 4.8 5.5 2.1 +4.2 +585 .5 19 2 9.5 4.7 5.5 2.2 +4.3 +585.6 20 1 11.4 4.5 5.1 2.4 +4.8 +586.1 20 2 9.9 4.3 5.3 2.3 +4.8 +586 .1 21 1 10.9 4.4 7.1 2.2 +4.1 +585.4 21 2 9.3 3.9 7.0 1.9 +3.9 +585 .2 22 1 11.0 5.0 5.5 1.5 +3.4 +584.7

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding NextEra Energy- PBNP ENERCON March 6, 2015 Excellence- Every project. Every day. FPL-076-FHRPR-002, Revision 2 WSEL WSEL Hs (ft-Scenario Approach h (ft) T (s) R (ft) (ft-(ft) Plant NAVD88)

Datum) 22 2 9.4 4.8 5.5 1.7 +3.7 +585.0 23 1 11.4 4.3 5.5 2.3 +4.7 +586.0 23 2 9.8 4.4 5.6 2.3 +4.7 +586.0 24 1 11.3 4.7 5.3 2.5 +4.7 +586.0 24 2 9.7 4.4 5.4 2.2 +4.6 +585 .9 25 1 11.0 3.8 5.9 2.0 +4.1 +585.4 25 2 9.2 3.6 7.1 1.9 +3.7 +585.0 26 1 11.0 4.7 6.7 1.9 +3.9 +585.2 26 2 9.4 4.7 6.8 2.1 +4.0 +585.3 27 1 10.8 4.6 5.1 1.6 +3.4 +584.7 27 2 9.2 4.3 5.1 1.7 +3.5 +584.8 28 1 11.1 4.5 5.9 2.4 +4.5 +585.8 28 2 9.5 4.0 5.9 1.9 +4.1 +585.4 29 1 12.7 7.1 8.6 1.4 +5.1 +586.4 29 2 11.1 6.2 8.5 1.5 +5 .2 +586.5 30 1 11.0 1.2 3.2 0.5 +2.5 +583.8 30 2 9.4 1.3 3.2 0.5 +2.5 +583 .8 31 1 12.7 7.1 8.6 1.4 +5.0 +586.3 31 2 11.1 6.2 8.5 1.5 +5 .2 +586.5 32 1 11.0 3.8 5.7 2.0 +4.0 +585.3 32 2 9.4 3.4 5.4 1.5 +3.5 +584.8 33 1 11.3 4.7 5.7 2.5 +4.7 +586.0 33 2 9.6 4.2 5.8 2.I +4.4 +585.7 34 1 I 1.0 2.0 3.8 0.9 +2.9 +584.2 34 2 9.4 1.9 3.8 0.8 +2.8 +584.1 35 1 Il.O 2.5 4.8 1.3 +3.3 +584.6 35 2 9.4 2.3 4.6 1.0 +3.0 +584.3 36 1 11.5 4.1 5.8 2.6 +5.1 +586.4 36 2 9.8 3.7 5.6 2.1 +4.6 +585.9 37 1 11.3 4.7 6.2 2.7 +5 .0 +586.3 37 2 9.8 4.6 6.7 2.6 +4.9 +586.2 38 1 I 1.2 2.8 5. I 1.6 +3.8 +585.I 38 2 9.5 2.6 4.9 1.3 +3.5 +584.8 39 1 I 1.4 2.8 4.4 1.7 +4.1 +585.4 39 2 9.7 2.6 4.3 I.4 +3.7 +585.0 40 1 10.7 2.0 3.2 0.6 +2.4 +583 .7 40 2 9.1 2.0 3.2 0.6 +2.4 +583 .7 41 1 11.8 4.0 5.3 3.0 +5.9 +587.2 41 2 10.2 4.1 5.8 2.7 +5 .5 +586.8 42 1 11.0 0.9 1.5 0.2 +2.2 +583.5 42 2 9.4 0.9 1.6 0.2 +2.2 +583.5 43 1 10.7 4.3 5.2 1.6 +3.3 +584.6 43 2 9.1 4.2 5.2 1.7 +3.4 +584.7 44 1 11.4 4.2 4.8 2.3 +4.7 +586.0 44 2 9.9 4.4 5.4 2.4 +4.9 +586 .2

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding p;:*r E N E R C 0 N NextEra Energy- PBNP March 6, 2015 Excellence- Every p roject. Every day.

FPL-076-FHRPR-002, Revision 2 WSEL WSEL Hs (ft-Scenario Approach h (ft) T (s) R (ft) (ft-(ft) Plant NAVD88)

Datum) 45 1 10.7 3.1 4.6 1.2 +2.8 +584.1 45 2 9.1 3.1 4.5 1.2 +2.9 +584.2

References:

None

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding ENERCON NextEra Energy- PBNP March 6, 2015 Excellence-Every project. Every day FPL-076-FHRPR-002, Revision 2 Table 4.12- PMSS Results at PBNP Peal{ WSEL at PMSSSWLH Water Wave Beach Riprap Scenario Hs T Depth (ft- Run up (ft-(ft) (s) (ft- (ft-(ft) Plant (ft) 13 Plant NAVD88) NAVD88)

Datum) Datum)

PMSS 3.7 2.4 11.0 +4.5 +585.8 +3 .9 +8.4 +589.7

References:

None 12 SWL is presented at the timestep of maximum WSEL, this is not necessarily the peak SWL.

13 Runup is calculated using the empirical USACE (2008) formulae for runup on a gently sloping, impermeable surface.

,.. ENERCON Excellence- Every project. Every day NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding NextEra Energy- PBNP March 6, 2015 FPL-076-FHRPR-002, Revision 2 Table 4.13- Peak Seiche SWL from Squall Line Events Antecedent Lake Level,t 4 Maximum Seiche Total Maximum SWL, Squall Line Event (ft-NAVD88) (ft-Plant Datum) Amplitude, (ft) (ft-NAVD88) (ft-Piant Datum)

Maximized May 31,

+583.1 +1.8 + 1.0 +584.1 +2.8 1998 Derecho Event

References:

None 14 Antecedent Lake level for the maximum seiche simulations was the 100-year recurrence monthly average high Lake level, +583 .1 ft-NAVD88 (+ 1.8 ft-Plant Datum).

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding NextEra Energy- PBNP ENERCON March 6, 2015 Excellence-Every project. Every day FPL-076-FHRPR-002, Revision 2 Table 4.14- Low Water SWL from Synoptic and Squall Line Events Antecedent Lake Level, 15 Maximum Minimum SWL, Wind Event (ft-NAVD88) (ft-Plant Datum) Setdown, (ft-NAVD88) (ft-Piant Datum)

(ft)

Jan . 25-28, 1978 N

+575.6 -5.7 -1.0 +574.6 -6.7 Transposed Synoptic Jan. 25-28, 1978 SW

+575 .6 -5.7 -0.3 +575.3 -6.0 Transposed Synoptic Oct. 27-28,2010 NW

+575.6 -5.7 -1.2 +574.4 -6.9 Transposed Synoptic Oct. 29-Nov. 1, 2012 NW

+575.6 -5.7 -1.3 +574.3 -7.0 Transposed Synoptic Oct. 27-28, 2010 NW Transposed Synoptic, +575.6 -5 .7 -1.1 +574.5 -6.8 Shifted E Oct. 27-28,2010 NW Transposed Synoptic, +575.6 -5.7 -1.3 +574.3 -7.0 Shifted N Oct. 29-Nov. 1, 2012 NW Transposed Synoptic, +575 .6 -5 .7 -1.3 +574.3 -7.0 Shifted E Oct. 29-Nov. 1, 2012 NW Transposed Synoptic, +575.6 -5.7 -1.3 +574.3 -7.0 Shifted N Jul. 13-14, 1995 Shifted

+575.6 -5.7 -0.3 +575.3 -6.0 Squall Line May 31, 1998 Shifted

+575.6 -5.7 -0.9 +574.7 -6.6 Squall Line Oct. 29-Nov. 1, 2012 NW Transposed Synoptic,

+575.6 -5.7 -3.3 +572.3 -9.0 Shifted N with Wind Corrections

References:

None 15 Antecedent Lake level for the low-water simulations was the 100-year recurrence monthly average low Lake level,

+575.6 ft-NA VD88 (-5.7 ft-Plant Datum).

NTTF Recommendation 2.1 (Hazard Reevaluations) : Flooding ENERCON NextEra Energy- PBNP March 6, 2015 Excellence-Every proj ect. Every day.

FPL-076-FHRPR-002, Revision 2 Table 4.15- Hydrostatic and Hydrodynamic Loads during LIP Event Scenario A Scenario B Door Static Impact Total Static Impact Total Force, Force, Force, Force, Force, Force, (lbs/ft) (lbs/ft) (lbs/ft) (lbs/ft) (Ibs/ft) (lbs/ft) 1 112.6 1.0 113.7 195.0 3.5 198.5 2 112.6 1.9 114.5 195.0 6.7 201.7 Turbine 4 112.6 0.7 113.3 195.0 3.5 198.5 Building 11 137.6 2.7 140.2 210.9 7.4 218.3 13 137.6 3.2 140.8 210.9 7.0 217.9 600 1.2 0.1 1.3 1.2 0.1 1.3 601 0.3 0.0 0.3 0.3 0.0 0.3 Diesel 602 7.8 0.5 8.3 7.8 0.4 8.2 Generator 603 2.8 0.7 3.5 2.8 0.7 3.5 604 15.3 0.1 15.4 15.3 0.1 15.4 151 112.6 1.3 113.9 112.6 1.4 114.0 152 137.6 6.6 144.2 137.6 8.3 145.9 154 165.0 6.0 171.0 165.0 3.4 168.4 159 179.7 6.6 186.3 179.7 4.5 184.2 Unit 1 &

167 151.0 5.4 156.4 151.0 3.5 154.5 Unit2 209 31.2 1.1 32.3 31.2 1.1 32.3 210 112.6 0.7 113.4 112.6 1.0 113.7 231 165.0 5.6 170.6 165.0 5.8 170.9 232 195.0 8.2 203.2 195.0 8.7 203.7 310 31.2 2.4 33.6 31.2 4.3 35.5 311 25.3 27.5 52.8 25.3 26.7 52.0 Service 312 25 .3 24.3 49.6 25.3 23.2 48.4 Building 313 44.9 11.2 56.1 44.9 9.1 54.1 314 37.8 2.2 39.9 37.8 2.1 39.9 33616 137.6 140.6 278.2 195.0 70.3 265.3 338 244.6 22.3 266.9 360.7 69.9 430.5 CWPH 339 244.6 21.2 265.8 339.8 29.4 369.1 34012 165.0 102.7 267.7 210.9 205.2 416.2 G501 137.6 2.2 139.8 137.6 2.9 140.5 G502 137.6 1.1 138.7 137.6 1.2 138.8 G5 G503 151.0 0.4 151.4 151.0 0.7 151.8 Building G504 124.8 6.7 131.5 124.8 4.1 128.9 G505 101.1 38.2 139.3 101.1 31.2 132.3

References:

None 16 For Scenario B, the cells adjacent to Door 336 and Door 340 were manually elevated to account for temporary wave barriers. Loading values were taken from the closest, unaltered model cells; accordingly, the Scenario B total forces apply only to the barriers at these locations. The Scenario B hydrostatic force component still applies to Door 336 and Door 340. Thus, the bounding total force at Door 340 is for Scenario A (267.7 lbs/ft).

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding ENERCON NextEra Energy- PBNP March 6, 2015 Excellence-Every proj ect. Every day.

FPL-076-FHRPR-002, Revision 2 Table 4.16- Waterborne Projectile Debris Impact Forces and Pressures Waterborne Waterborne Projectile Velocity Projectile Impact (ft/s) Impact Pressure Force (lb)

-~f)_

1 6,088 4,961 2 12,176 9,922 3 18,264 14,883 4 24,352 19,844 5 30,440 24,805 6 36,528 29,766 7 42,6 16 34,727 8 48,704 39,688 9 54,792 44,649 10 60,881 49,610 11 66,969 54,571 12 73 ,057 59,532 13 79,145 64,493 14 85,233 69,454 15 91,321 74,415 16 97,409 79,376 17 103,497 84,337 18 109,585 89,298 19 115,673 94,259 20 121,761 99,220

References:

None

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding ENERCON NextEra Energy- PBNP March 6, 2015 Excellence- Every proj ect. Every day.

FPL-076-FHRPR-002, Revision 2 Table 5.1- Comparison of CLB and FHR Flooding Levels by Mechanism and Component Current License Basis Flood Hazard Reevaluation Mechanism (CLB) (FHR)

- .~....= PMP/LIP 4.9 in. over 6 ht* 17 12.8 in. over 1 ht*

....co:

....c.

C.J PMP/LIPMaximum Flow Up to 0.8 ft at CWPH Up to 3.4 ft at CWPH

<U

~ "" Depths (See Table 3 .I) (See Table 4.2)

Riverine N/A N/A Dam Breaches and Failures N/A N/A

+583.0 ft-NA VD88 +583.1 ft-NA VD88 Antecedent Lal{e Level

(+ 1.7 ft-Plant Datum) (+ 1.8 ft-Plant Datum) 00 Maximum Storm Surge 5.14ft 18 4.5 ft 00

~ 6.55 ft on ve1tical structure N/A on vertical structure20 Poe Maximum Wave Runup 5.38 ft on 1:1.5 riprap slope 19 3.9 ft on 1:2 riprap slope

+589.72 ft-NAVD88 +589.7 ft-NA VD88 PeakWSEL

(+8.42 ft-Plant Datumf 1 (+8.4 ft-Plant Datum)22

+583 .1 ft-NA VD88 Antecedent Lal{e Level N/A

<U (+ 1.8 ft-Plant Datum)

..=

C.J

'Qj Maximum Seiche Amplitude 1 to 2ft 1.0 ft 00

+584.1 ft-NA VD88 PeakSWL N/A

(+2.8 ft-Plant Datum)

Tsunami N/A N/A Ice-Induced Effects N/A N/A 17 This volume of water is the sum of the water content of snow in late March with a 50-year recurrence frequency and the volume fi*om a six-hour rainfall with a 50-year recurrence frequency (NEE, 20 14b).

18 Storm surge of +4.14 ft added to the maximum recorded Lake Michigan water level, +583.0 ft-NAVD88

(+ 1. 7 ft-Plant Datum) and a + 1.0 ft increase for velocities equal or greater than 70 knots (NEE, 20 14b ).

19 Slopes are repmied as ve1iical (V) to horizontal (H), V:H.

20 There is no standing water at PBNP ve1iical structures during the PMSS event; therefore, there is no wave runup directly on a ve1iical structure (Section 4.4.1 0).

21 Maximum flood elevation equals the maximum recorded Lake Michigan water level, +583.0 ft-NA VD88

(+ 1.7 ft-Plant Datum), +0.17 ft of wind tide setup, and +6.55 ft of wave run up on a ve1iical structure (NEE, 20 14b).

22 Maximum combined storm surge and wave runup above the 100-year recurrence monthly average high Lake level at the crest of the riprap slope. Peak WSEL does not necessarily occur at maximum storm surge or maximum wave runup (NEE, 2014b).

NTTF Recommendation 2.1 (Hazard Reevaluations): Flooding F~*r E N E RC 0 N NextEra Energy- PBNP March 6, 2015 Excellence-Every project. Every day FPL-076-FHRPR-002, Revision 2 Current License Basis Flood Hazard Reevaluation Mechanism (CLB) (FHR)

- +576.5 ft-NA VD88 +575.6 ft-NA VD88 Antecedent Lake Level

..."=

l.

~ (-4.8 ft-Plant Datum) (-5.7 ft-Plant Datum)

Maximum Wind Setdown N/A -3.3 ft

~

Q

....:l +576.5 ft-NA VD88 +572.3 ft-NA VD88 Minimum SWL

(-4.8 ft-Plant Datum) (-9.0 ft-Plant Datum)

References : NEE, 2014b

NextEra Energy (NEE)

Point Beach Nuclear Plant (PBNP)

ENERCON Flooding Hazards Reevaluation Report (FHRR)

Figure 2.1 PBNP Site Location

References:

ESRI, 2012 FPL-076-FHRPR-002 REV. 2

NextEra Energy (NEE)

Point Beach Nuclear Plant (PBNP)

ENERCON Flooding Hazards Reevaluation Report (FHRR)

Figure 4.1 PBNP Site Features

References:

ESRI, 2012 ; NEE, 2014b FPL-076-FHRPR-002 REV. 2

14 12

~

~ "' 10

(.)

.51 s:::

.Q ell

.-;:: 8

.e.

(.)

~

A..

-~

6

l E

l u

4 0

0 10 20 30 40 so 60 Time (minutes)

- Quartile 1 - Quartile 2 - Quartile 3 - Quartile 4 NextEra Energy (NEE)

Point Beach Nuclear Plant (PBNP)

-:d ENERCON Flooding Hazards Reevaluation Report (FHRR) Figure 4.2 PBNP LIP Hyetographs

References:

FPL-076-FHRPR-002 REV. 2

re-ea 48

• 50 0 85 170 340 Feet

41. ~s

12.4 1 2.; - 32 10

• 24 8* 10

. 0.9*8

- -i- 0.9 NextEra Energy (NEE)

Point Beach Nuclear Plant (PBNP)

ENERCON Flooding Hazards Reevaluation Report (FHRR)

Figure 4.3 PBNP DTM Elevations

References:

FPL-076-FHRPR-002 REV. 2

Legend

• -- - ,sito Bo11nd'*ry it.lnnlngJ'Ii NNtt1Lilo

~

M

!* -_,., -ct_ ,~~of,_~.,__, 1- --to-NextEra Energy (NEE)

Point Beach Nuclear Plant (PBNP)

ENERCON Flooding Hazards Reevaluation Report (FHRR)

Figure 4.4 PBNP Manning's Roughness Coefficient Spatial Distribution

References:

FPL-076-FHRPR-002 REV. 2

• Doorlocation J Temporary Structure Permanent Structure Switchgear Enclosure Turbine Building Units 1 & 2 Facade

• • ~

il

~ I

,j

, *1

.~

0 100 20<0, NextEra Energy (NEE) ~ ENERCON Point Beach Nuclear Plant (PBNP)

Figure 4.5 Flooding Hazards Reevaluation Report (FHRR)

PBNP Door Locations

References:

FPL-076-FHRPR-002 REV. 2

LEGEND

• PBNP Doors or Intere-st D Per mar cn t Sttuctures f~ j Temporary Structures r:::J Fl0 *2D Bo ll'ldary

- - ToJX19raphic C{}ntoors 0 120 240 4SO Peet Croin<J(te Basin Jr-+-~-+--lr-+-~-+~1 NextEra Energy (NEE)

Point Beach Nuclear Plant (PBNP)

Flooding Hazards Reevaluation Report (FHRR)

Figure 4.6 Direct Drainage Area at PBNP

References:

FPL-076-FHRPR-002 REV. 2

NextEra Energy (NEE)

Point Beach Nuclear Plant (PBNP)

Flooding Hazards Reevaluation Report (FHRR)

Figure 4.7 LIP Maximum Flow Depths- Scenario A

References:

FPL-076-FHRPR-002 REV. 2

0.61- 1.00

- 1.01-1 .40

- 1.41 - 2.00

. 2.01-2.70

- 2,71-4.10

- 4.11-6.20 250 NextEra Energy (NEE)

Point Beach Nuclear Plant (PBNP)

ENERCON Flooding Hazards Reevaluation Report (FHRR)

Figure 4.8 LIP Maximum Flow Depths- Scenario B

References:

FPL-076-FHRPR-002 REV. 2

Point Beach LIP Grid Cell 73842 3~------~------~----~------~------~------~

Scenmio B Door 13 2.573 ft 2.5 -

..c 0.

~ 1.5 3:

0 u.. 1 0.5 0~ 0 2 I

4 6 8 10 12 Elapsed Time (hours)

NextEra Energy (NEE)

Point Beach Nuclear Plant (PBNP)

Flooding Hazards Reevaluation Report (FHRR)

<<JJ ENERCON Figure 4.9 LIP TB Door 13 Water Depth Time Series- Scenario B References : FPL-076-FHRPR-002 REV. 2

initial bed l~evel (m) 6 27 -Oct-20*10 00:00:00

]x 10 2 300 2.6 I ......__..,.... ,._ .l' l.:.:ift\.~

200 1

2.5 ~

1 -

J .. ill ,,. "J J.'I "' I n

I I 100

'E2.4

- <!)

~

~

I { ' *, .it, l- ..... :1 0'

'E!

8

(,;)

2~3 J \- * -10 2.1 -200

x coordinate ~m) _,~

NextEra Energy (NEE) Point Beach Nuclear Plant (PBNP)

                                                                                                                              ~:d ENERCON Flooding Hazards Reevaluation Report (FHRR)                                                                              Figure 4.10 Delft3D-FLOW Representation of Lake Michigan and Lake Huron

References:

FPL-076-FHRPR-002 REV. 2

initial bed level {m) 27~Oct.-201 0 00:*00:00 2.397 "X 1or;. 2.3965 25

                                                                                                                     .20
           'E       .2.396
           - ( !)
            '(6 15 s::
           ~ ...

0 10 8 2.39~5 5

                     .2.395                                                                                            I)
                                                                                                                       -5 2.394.5                          I
                         *6 .715       6.72      6.725         6.73         6~735  *6 .74 6.745        6.75 1              *- 11)1 x coordinate {m) -).                  x 10 15
                                                                                                                        -15 NextEra Energy (NEE)

Point Beach Nuclear Plant (PBNP) F.:;d ENERCON Flooding Hazards Reevaluation Report (FHRR) Figure 4.1 1 Delft3D-FLOW Representation of PBNP Nearshore

References:

FPL-076-FHRPR-002 REV. 2

N

                                                                                                             ~

A e NOAA Water Level Statio11n 0 25 50 100 Miles ............ Great Lakes Sihorellne I ro 11 1 1- ~ _,. 1 I NextEra Energy (NEE) Point Beach Nuclear Plant (PBNP) F::ji ENERCON Flooding Hazards Reevaluatio n Report (FHRR) Figure 4.12 NOAA Water Level Stations Considered for Calibration and Validation

References:

NOAA, 2014b through NOAA, 2014r FPL-076-FHRPR-002 REV. 2

N~ A .A 45003 45008 A L

                                                                                      -    Great lak.es S!li lorellne 0     25 50                           A  NOAA 'B uoy Stations I  I   I~ I I li I I I NextEra Energy (NEE)

Point Beach Nuclear Plant (PBNP) F:~ ENERCON Flooding Hazards Reevaluation Report (FHRR) Figure 4.13 NOAA Buoy Stations Considered for Calibration and Validation

References:

NOAA, 2014s through NOAA, 2014gg FPL-076-FHRPR-002 REV. 2

NO,AA Station: 9087068 177 *------~----~----~----~----~----~ RMISE: 0.068 m 176.5 NSE*: 0.,681 u:; 1'75.5 f/)

~

175

                                                                 - .Simulated
                                                                  ---...O'bserved 2:0           40       60          80                           120 E lapsed T1 ime (hours),

NextEra Energy {NEE) Point Beach Nuclear Plant {PBNP) Flooding Hazards Reevaluation Report {FHRR) Figure 4.14 NOAA Station 9087068 Final Calibration Near PBNP

References:

NOAA, 2014c FPL-076-FHRPR-002 REV. 2

NOAA Buo,y: 45022 15*r---------,------,-----.-------,r-;=:====::r:======::::;., RMSE: r0 .483 m S'imulated

                                                                       . o~bserved NSE: Or834 10
     ~

E

     .5!3 U)

I:

5 40 60 80 100 120 Elapsed Time (hours) NextEra Energy (N EE) Point Beach Nuclear Plant (PBNP) ENERCON Flooding Hazards Reevaluation Report (FHRR) Figure 4.1 5 NOAA Buoy 45022 Final Calibration in Shallow Water

References:

NOAA, 2014t FPL-076-FHRPR-002 REV. 2

180 .----* .. **.-.- - - ,------ RMSE:: Oe03a m 1

1. 79 1 NS~ E: ~0,7,22 176 1

                                                                ' - s~mu!ated
                                                                  ----* Observed 11750 20              40        60                00            100 E~apsed Tim~ (h.ou rs.)

NextEra Energy (NEE) Point Beach Nuclear Plant (PBNP)

                                                   ~ ENERCON Flooding Hazards Reevaluation Report (FHRR)

Figure 4.16 NOAA Station 9087068 Water Surface Elevation for the 1985 Validation Event

References:

NOAA, 2014t FPL-076-FHRPR-002 REV. 2

                                       !N OAA Station: 9087072:

1180 RMSE:* Oe076* m 179 NS E: o~N466 w 177 tn 3: ..... ... 176

                                                                    - s :limu~ted
                                                                    ----*Observed 20         AD*     eo           eo           100           120 Elapsed l ime (~ou ~s)

NextEra Energy (NEE) Point Beach Nuclear Plant (PBNP) ENERCON Flooding Hazards Reevaluation Report (FHRR) Figure 4.17 NOAA Station 9087072 Water Surface Elevation for the 1990 Validation Event

References:

NOAA, 2014i FPL-076-FHRPR-002 REV. 2

15 r-----.------.------r- . ----~====~====~ Cjon =0.060

                                                                  - ~--* Cjon ~      0.0 75, 1

10 E

    -~

il) J: 5

                                                                             ----*         ~

o ~------~------~j--------L-*------~l~------~~------~ 0 20 40 60 80 100 120 Elapsed Trime (hours) NextEra Energy (N EE) Point Beach Nuclear Plant (PBNP) Flooding Hazards Reevaluation Report (FHRR) 0 ENERCON Figure 4.18 C JoN Sensitivity Analysis Results for NOAA Buoy 45022

References:

FPL-076-FHRPR-002 REV. 2

NOAA Buoy: 450.2*2 RMSE: 0.503 m 1

• S*im ul~ded

                                                                        . o~bserved NSE: 0..82 10 E

D)

     *-U)
     ~

5 0 ~----~------~----~~~----~----~----~ 0 20 40 60 80 100 120 Elapsed Time (hours) NextEra Energy (NEE) Point Beach Nuclear Plant (PBNP) ENERCON Flooding Hazards Reevaluation Report (FHRR) Figure 4.19 Depth-Induced Breaking Sensitivity (y =0.73) for NOAA Buoy 45022

References:

NOAA, 2014t FPL-076-FHRPR-002 REV. 2

NOAA Buoy: 4502*2 15 r---~----~----~----~====~==~ RMSE: 0.483 m

• S:hin ulated
• Obse~rved NSE*: Q.834 10'

    ~

E Dl U)

I:

5 20 40 60 80 100 120 Elapsed T1ime (hours) NextEra Energy (NEE) Point Beach Nuclear Plant (PBNP) F.:tl ENE R C 0 N Flooding Hazards Reevaluation Report (FHRR) Figure 4.20 Depth-Induced Breaking Sensitivity (y =0.55) for NOAA Buoy 45022

References:

NOAA, 2014t FPL-076-FHRPR-002 REV. 2

25 6 Initial Bed Elevation (m-Model Datum) X 10 20 2.3959 15 2.3958 10 t

           -2.3957                                                                                                              5
           -~E
           *=
            "E 2.3956 0

0 0 (.)

                                                                                                                                -5
             >- 2.3955
                                                                                                                                -10 2.3954
                                                                                                                                -15 2.3953 6.725   6.726     6.727    6.728       6.729  6.73     6.731 6.732 6.733   6.734                  -20 x coordinate (m) - )                            5 X 10
                                                                                                                                -25 Coordinate System- Cartesian GCS NAD27, Albers projection NextEra Energy (NEE)

Point Beach Nuclear Plant (PBNP) 1\:ll ENERCON Flooding Hazards Reevaluation Report (FHRR) Figure 4.21 Nearshore Grid 4 Showing Observation Point Locations

References:

FPL-076-FHRPR-002 REV. 2

1 Fraction Breaking (Percent) 6 X 10 0.9 2.3958 0.8 2.3958 2.3958 0.7 t 2.3957 g IV 2.3956 0.6 a; 0.5

                   .!: 2.3956
                   'E 0

8 2.3956 0.4 2.3955 0.3 2'.3954 2.3954 0.2 2.3954 6.726 6.727 6.728 ;6.729 6.73 6.731 6.732 6.733 0.1 x coordinate (m) - >- X 105: Coordinate System- Cartesian GCS NAD27, Albers projection 0 NextEra Energy (NEE) Point Beach Nuclear Plant (PBNP) Flooding Hazards Reevaluation Report (FHRR) Figure 4.22 Wave Breaking Locations for PMWS (Scenario 13) with Adiusted Wind Fields

References:

FPL-076-FHRPR-002 REV. 2

                                                      ~ T     (~c) a: . . . 15*- * - 10 b: - ~ 6 C: -.5-.oQI a: *o-s e:        .5 -"o
                                                    ~~       10..-15
                                                  ~~---liillli e
                                                    ~~            ........ ,

o *......._~~~~~~~~~.i!i-~-~ o 2*,s .s.o 1~5 1o~. o Ovedand* Wind Speed (m .s ~ *1 ) NextEra Energy (NEE) Point Beach Nuclear Plant (PBNP) ENERCON Flooding Hazards Reevaluation Report (FHRR) Figure 4.23 Coefficient for Calculation of Overwater Wind Speed

References:

Schwab and Morton, 1984 FPL-076-FHRPR-002 REV. 2

10 5-

       .. 1Q
       -15 _~-------~----------~--~--------~~~~

0 0.2 0.4* 0.6 0.8 1 Cumulative Distribution Function (CDF) NextEra Energy (NEE) Point Beach Nuclear Plant (PBNP) ENERCON Flooding Hazards Reevaluation Report (FHRR) Figure 4.24 CDF of Observed Air and Water Temperature Differences at NOAA Buoy 45007; 95% Exceedance (Blue Line)

References:

FPL-076-FHRPR-002 REV. 2

water level (m) 6 10-Jan-197518:15:00 x10 I 2.3958 0.95 2.3958* 2 .3958, O.B 2.3957 1' 0..85 E' 2.395:6,

         - 2.395:6; (I)
          ~
         "0 o..s
          ~

8 2.395:6 0.75 2.395S 2.3954 0.7 2.3954 2.3954 0.66 6.726 6.727 6.728 *6.729 6.73 6.731 16.732 x coordinate (m) ~ X 10 5 0.6; NextEra Energy (NEE) Point Beach Nuclear Plant (PBNP)

                                                                                                  ,;JJ   ENERCON Flooding Hazards Reevaluation Report (FHRR)                                     Figure 4.25 Peak PMSS SWL at PBNP

References:

FPL-076-FHRPR-002 REV. 2

E' 1.5

c.5 Q) 1 0

Cl

                .5 0.5 ro e!          0 00 0  10      20      30       40        50       60         70 1

e

               -19        0.5 ii)

I:

10 20 30 40 50 60 70 15

                 ~
                 '0 0

10

                 *c:::

Q) 5 0. 0 0 10 20 30 40 50 60 70 2 g g-1 c:

J 0::

10 20 30 40 50 60 70 3

                    .S2
                    ...J
                                    ,I I
                    ~~yw 0

0 10 20 30 " 40

                                                           .. ,~

Elapsed Time (hours) 50 60 70 NextEra Energy (NEE) Point Beach Nuclear Plant (PBNP) ENERCON Flooding Hazards Reevaluation Report (FHRR) Figure 4.26 PMSS Results and Wave Runup on a Gently Sloping Impermeable Surface- South Approach

References:

FPL-076-FHRPR-002 REV. 2

200 400 Feel NextEra Energy (NEE) Point Beach Nuclear Plant (PBNP) ENERCON Flooding Hazards Reevaluation Report (FHRR) Figure 4.27 Peak PMSS SWL Inundation Map at PBNP

References:

ESRI, 2012; NEE, 2014b FPL-076-FHRPR-002 REV. 2

Lake Huron Observed Computed Water Level at Goderich, Ontario 177.2 177 ***--*~***- *'*"*--* - ,,._.. , ......... *-*-* j-*-*-**- ....__ * *~--- *****-*-*

           ~      176.8 L{)

CX) 0 176.6 _J C) 176.4 I Qi (!) _J 2rn s 16:00 17:00 18:00 19:00 20:00 21 :00 22:00 23:00 00:00 01 :00 02:00 03:00 04:00 05:00 July 13, 1995 Time July 14, 1995 Lake Huron Observed Computed Water Level at Port Huron, Michigan 177.5 - ([) CX) 0 _J 177 1-* - - - - ' ~-* --- I , =-... ---- -

                                                                                                                           \."'                        I-----                                --J C)
                                                                                                       ---~'                                           :
           ~~
                 ' 176.51:c _ _ _ _             ,----

(!) _J \ I

            '-                                                                                   .... .1' -*****

2

           ~
                             - - - Port Huron, Mlobs
                             ~    -  Port Huron. Ml""""

1 75~~~-~~-~~~-~~--~~~--~~--~~~--~~--~~~~~~--~~~~ 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 00:00 01 :00 02:00 03:00 04:00 05:00 July 13, 1995 July 14, 1995 Time NextEra Energy (NEE) Point Beach Nuclear Plant (PBNP) F.:d ENERCON Flooding Hazards Reevaluation Report (FHRR) Figure 4.28 Lake Huron Observed Versus Modeled Values for July 13, 1995 Derecho Event

References:

FPL-076-FHRPR-002 REV. 2

Grid 4 Observation Points- May 31 , 1998 Derecho Event 0 0 0 0 0 0 0 0 0 llmf8-) 0 0 0 0 0 0 0 0

                     <'0 0
                                ~

0

                                         'i N

0 N

                                                ,.... 0 0         .,.
                                                                    ~             u; M

a;

                                                                                            ;i1; c-;

0 0 (I)

                     ~

0 (I) iri 0 CIO

                                         ~

CIO

                                                ...a; (I) 0 0
                                                          <0
                                                                    ~*
                                                                    <0 0
                                                                                  <0
                                                                                            ~

CIO

                                                                                                      ~
                                                                                                      <0 8:          8:        $...      8:     g:        0>        0>            0>        0>        a>
         ....        .,..                ....   ...>.     ~         0>

c

                                                                                  ~

c. a> c.

                                                                                                      ~

t

          ...:>..     .,:>..     ...:>..  ...>.  ...       1:

1  ::J  ::J  ::J  :>

         ~

i'i

                     ~
                               ~

M

                                         ~

lf 7

7 b ... 7 0 7 0 7<F-0 NextEra Energy (NEE) Point Beach Nuclear Plant (PBNP) ENERCON Flooding Hazards Reevaluation Report (FHRR) Figure 4.29 Modeled Seiche Amplitudes near PBNP for Maximized May 31, 1998 Derecho Event References : FPL-076-FHRPR-002 REV. 2

                                                                                                                                                  .l S a uft s t e. *
                                                                                                                                   ,o-r,!Jarfe
                                                                 **             *~
                                                                                     ~
                                                                                       ~
                                                              ,_                       I ,:_

l'vt I EJJ N I SC N ~ IN *

                                       , ~ ~LI I tt    I 'C tr..;.;    ,..--         .-

• 1 rv111 1JVC1LI kee

                                                                    .o
                            , -~....             rvU Jd is           n                                                           L a n s il-ig
                                            ~

Q .

                          . "<<,.~.

J~* r_..*

                                                  ~-                             .** c hi a g I LL.IN O l                                I NDL            N A          -

S l r il g fi l l:l o *0 lnr *Ii a n a li s C in inn a t

                                                                                                                     .I
                                                           ,.                         r                   L oui::.v ille
                                                           '                                                    0 Legend K ~ NT               . Y *.

• Tsunami Runup

**  Tsunami Event Point Beach Nuclear Plant                                            0    75

r 150 300 Miles NextEra Energy (NEE)

Point Beach Nuclear Plant (PBNP) ENERCON Flooding Hazards Reevaluation Report (FHRR) Figure 4.30 Historical Tsunami Runup and Events near PBNP

References:

NOAA, 2014hh FPL-076-FHRPR-002 REV. 2

                      ~~ ~u a ~ire

" WISCO NS IN I J

                                                                                                                                    ~
                                                                                                                                    ~

I

                                                                                                                              ...~-

I I

                                                                                                                           ~

La *c?.Js<§e** Fond 0 ':.. J ... .. . dul ~ c

                       .. .                 ~~~-
                                       . .. "J**            -:
                                                        ~                                               .-;:;-.
                                                    ,: ;    \~('Q ,-'1'~1! t.t.;, *'

rV! aciison _~~ l'v1ilwau kee l 1.

                                               .I                                                                                                  ~ra n d Rapids         /   1
                                                  '\
                                                                                                                                                 \               Lansin g looJ                              ' D u~u9;~- ---- - --

I 0

                                                                     )                                                                      K::tlamazoo Portag~

c~oor_ "' .... 0 Rapid s** 0 0 f,p aq* south Bend Gl Legend

• Significant Earthquakes
• Strong Motion Location 0 40 80 160 Miles
• Point Beach Nuclear Plant NextEra Energy (NEE)

Point Beach Nuclear Plant (PBNP) F.:JJ ENERCON Flooding Hazards Reevaluation Report (FHRR) Figure 4.31 Historical Earthquake Events near PBNP

References:

NOAA, 2014hh FPL-076-FHRPR-002 REV. 2}}