ML18247A260

Revision 36 to Final Safety Analysis Report, Chapter 2, Site Characteristics

ML18247A260
Person / Time
Site:	Millstone
Issue date:	06/18/2018
From:	Dominion Energy Nuclear Connecticut
To:	Office of Nuclear Reactor Regulation
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References
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Millstone Power Station Unit 3 Safety Analysis Report Chapter 2: Site Characteristics

Table of Contents tion Title Page GEOGRAPHY AND DEMOGRAPHY ..................................................... 2.1-1 1 Site Location and Description..................................................................... 2.1-1 1.1 Specification of Location............................................................................ 2.1-1 1.2 Site Area ..................................................................................................... 2.1-1 1.3 Boundaries for Establishing Effluent Release Limits................................. 2.1-1 2 Exclusion Area Authority and Control ....................................................... 2.1-2 2.1 Authority ..................................................................................................... 2.1-2 2.2 Control of Activities Unrelated to Plant Operation .................................... 2.1-3 2.3 Arrangements for Traffic Control............................................................... 2.1-3 2.4 Abandonment or Relocation of Roads........................................................ 2.1-3 2.5 Independent Spent Fuel Storage Installation (ISFSI) ................................. 2.1-4 3 Population Distribution............................................................................... 2.1-4 3.1 Population Distribution within 10 miles ..................................................... 2.1-4 3.2 Population Distribution within 50 Miles .................................................... 2.1-5 3.3 Transient Population ................................................................................... 2.1-6 3.4 Low Population Zone.................................................................................. 2.1-6 3.5 Population Center ....................................................................................... 2.1-6 3.6 Population Density...................................................................................... 2.1-7 4 References For Section 2.1 ......................................................................... 2.1-7 NEARBY INDUSTRIAL, TRANSPORTATION, AND MILITARY FACILITIES........................................................................... 2.2-1 1 Locations and Routes.................................................................................. 2.2-1 2 Descriptions ................................................................................................ 2.2-1 2.1 Description of Facilities.............................................................................. 2.2-1 2.2 Description of Products and Materials........................................................ 2.2-3 2.3 Pipelines...................................................................................................... 2.2-5 2.4 Waterways .................................................................................................. 2.2-5 2.5 Airports ....................................................................................................... 2.2-5 2.6 Highways .................................................................................................... 2.2-6 28/18 2-i Rev. 31

tion Title Page 2.7 Railroads ..................................................................................................... 2.2-7 2.8 Projections of Industrial Growth................................................................. 2.2-7 3 Evaluation of Potential Accidents............................................................... 2.2-8 3.1 Determination of Design Basis Events .................................................... 2.2-12 3.1.1 Missiles Generated by Events near the Millstone Site ............................. 2.2-12 3.1.2 Unconfined Vapor Cloud Explosion Hazard ............................................ 2.2-19 3.1.3 .................................................................................................................. 2.2-19 3.1.4 Hydrogen Storage at the Site .................................................................... 2.2-22 3.1.5 Toxic Chemicals ....................................................................................... 2.2-22 3.2 Effects of Design Basis Events ................................................................. 2.2-24 4 References for Section 2.2 ........................................................................ 2.2-25 METEOROLOGY ...................................................................................... 2.3-1 1 Regional Climatology ................................................................................. 2.3-1 1.1 General Climate .......................................................................................... 2.3-1 1.1.1 Air Masses and Synoptic Features.............................................................. 2.3-1 1.1.2 Temperature, Humidity, and Precipitation ................................................. 2.3-2 1.1.3 Prevailing Winds......................................................................................... 2.3-2 1.1.4 Relationships of Synoptic to Local Conditions .......................................... 2.3-3 1.2 Regional Meteorological Conditions for Design and Operating Bases ...... 2.3-3 1.2.1 Strong Winds .............................................................................................. 2.3-3 1.2.2 Thunderstorms and Lightning..................................................................... 2.3-4 1.2.3 Hurricanes ................................................................................................... 2.3-4 1.2.4 Tornadoes and Waterspouts........................................................................ 2.3-4 1.2.5 Extremes of Precipitation............................................................................ 2.3-5 1.2.6 Extremes of Snowfall.................................................................................. 2.3-5 1.2.7 Hailstorms ................................................................................................... 2.3-5 1.2.8 Freezing Rain, Glaze, and Rime ................................................................. 2.3-6 1.2.9 Fog And Ice Fog ......................................................................................... 2.3-6 1.2.10 High Air Pollution Potential ....................................................................... 2.3-6 1.2.11 Meteorological Effects on Ultimate Heat Sink........................................... 2.3-6 28/18 2-ii Rev. 31

tion Title Page 2 Local Meteorology...................................................................................... 2.3-7 2.1 Normal and Extreme Values of Meteorological Parameters ...................... 2.3-7 2.1.1 Wind Conditions ......................................................................................... 2.3-7 2.1.2 Air Temperature and Water Vapor ............................................................. 2.3-7 2.1.3 Precipitation ................................................................................................ 2.3-8 2.1.4 Fog and Smog ............................................................................................. 2.3-8 2.1.5 Atmospheric Stability ................................................................................. 2.3-8 2.1.6 Seasonal and Annual Mixing Heights ........................................................ 2.3-9 2.2 Potential Influence of the Plant and Its Facilities on Local Meteorology .. 2.3-9 2.3 Local Meteorological Conditions for Design and Operating Bases ........... 2.3-9 2.3.1 Design Basis Tornado ................................................................................. 2.3-9 2.3.2 Design Basis Hurricane ............................................................................ 2.3-10 2.3.3 Snow Load ................................................................................................ 2.3-10 2.3.4 Rainfall...................................................................................................... 2.3-10 2.3.5 Adverse Diffusion Conditions .................................................................. 2.3-10 2.4 Topography ............................................................................................... 2.3-10 3 On-Site Meteorological Measurements Program ..................................... 2.3-11 3.1 Measurement Locations and Elevations ................................................... 2.3-11 3.2 Meteorological Instrumentation................................................................ 2.3-11 3.3 Data Recording Systems and Data Processing ......................................... 2.3-12 3.4 Quality Assurance for Meteorological System and Data.......................... 2.3-12 3.5 Data Analysis ............................................................................................ 2.3-13 4 Short-Term (Accident) Diffusion Estimates............................................. 2.3-13 4.1 Objective ................................................................................................... 2.3-13 4.2 Calculation ................................................................................................ 2.3-13 4.3 Results....................................................................................................... 2.3-13 5 Long Term (Routine) Diffusion Estimates ............................................... 2.3-14 5.1 Calculation Objective ............................................................................... 2.3-14 5.2 Calculations .............................................................................................. 2.3-14 5.2.1 Release Points and Receptor Locations .................................................... 2.3-14 5.2.2 Database.................................................................................................... 2.3-14 28/18 2-iii Rev. 31

tion Title Page 5.2.3 Models ...................................................................................................... 2.3-14 6 References for Section 2.3 ........................................................................ 2.3-14 HYDROLOGIC ENGINEERING ............................................................. 2.4-1 1 Hydrologic Description............................................................................... 2.4-1 1.1 Site and Facilities........................................................................................ 2.4-1 1.2 Hydrosphere................................................................................................ 2.4-1 2 Floods.......................................................................................................... 2.4-2 2.1 Flood History .............................................................................................. 2.4-2 2.2 Flood Design Considerations...................................................................... 2.4-3 2.3 Effect of Local Intense Precipitation .......................................................... 2.4-4 3 Probable Maximum Flood on Streams and Rivers ..................................... 2.4-7 4 Potential Dam Failures, Seismically Induced ............................................. 2.4-7 5 Probable Maximum Surge and Seiche Flooding ........................................ 2.4-7 5.1 Probable Maximum Winds and Associated Meteorological Parameters.... 2.4-7 5.2 Surge and Seiche Water Levels .................................................................. 2.4-8 5.3 Wave Action ............................................................................................. 2.4-10 5.3.1 Deep Water Waves ................................................................................... 2.4-10 5.3.2 Shallow Water Waves............................................................................... 2.4-12 5.3.3 Wave Shoaling .......................................................................................... 2.4-13 5.3.4 Wave Refraction ....................................................................................... 2.4-13 5.3.5 Wave Runup ............................................................................................. 2.4-14 5.3.6 Clapotis on Intake Structure ..................................................................... 2.4-14 5.4 Resonance ................................................................................................. 2.4-14 5.5 Protective Structures ................................................................................. 2.4-15 6 Probable Maximum Tsunami Flooding .................................................... 2.4-15 7 Ice Effects ................................................................................................. 2.4-16 8 Cooling Water Canals and Reservoirs ...................................................... 2.4-16 9 Channel Diversions................................................................................... 2.4-16 10 Flooding Protection Requirements ........................................................... 2.4-16 11 Low Water Considerations ....................................................................... 2.4-16 28/18 2-iv Rev. 31

tion Title Page 11.1 Low Flow in Rivers and Streams.............................................................. 2.4-16 11.2 Low Water Resulting from Surges, Seiches, or Tsunamis ....................... 2.4-17 11.3 Historical Low Water................................................................................ 2.4-18 11.4 Future Control........................................................................................... 2.4-18 11.5 Plant Requirements ................................................................................... 2.4-18 11.6 Heat Sink Dependability Requirements.................................................... 2.4-18 11.7 Dispersion, Dilution, and Travel Times of Accidental Releases of Liquid Effluents in Surface Waters ...................................................................... 2.4-19 12 Groundwater ............................................................................................. 2.4-23 12.1 Description and Onsite Use ...................................................................... 2.4-23 12.2 Sources...................................................................................................... 2.4-23 12.3 Accident Effects........................................................................................ 2.4-24 12.4 Monitoring or Safeguard Requirements ................................................... 2.4-28 12.5 Design Bases for Subsurface Hydrostatic Loading .................................. 2.4-28 13 Technical Specification and Emergency Operation Requirements .......... 2.4-28 14 References for Section 2.4 ........................................................................ 2.4-29 GEOLOGY, SEISMOLOGY, AND GEOTECHNICAL ENGINEERING ......................................................................................... 2.5-1 1 BASIC GEOLOGICAL AND SEISMIC INFORMATION ................... 2.5.1-1 1.1 Regional Geology .................................................................................... 2.5.1-1 1.1.1 Regional Physiography and Geomorphology .......................................... 2.5.1-2 1.1.2 Regional Structure ................................................................................... 2.5.1-3 1.1.3 Regional Stratigraphy .............................................................................. 2.5.1-6 1.1.4 Regional Tectonics .................................................................................. 2.5.1-6 1.1.4.1 Domes and Basins.................................................................................... 2.5.1-6 1.1.4.2 Faulting .................................................................................................... 2.5.1-7 1.1.4.3 Tectonic Summary ................................................................................. 2.5.1-10 1.1.4.4 Remote Sensing ..................................................................................... 2.5.1-10 1.1.4.5 Structural Significance of Geophysical Studies..................................... 2.5.1-11 1.1.5 Regional Geologic History .................................................................... 2.5.1-12 28/18 2-v Rev. 31

tion Title Page 1.2 Site Geology .......................................................................................... 2.5.1-16 1.2.1 Site Physiography .................................................................................. 2.5.1-16 1.2.2 Local Stratigraphy.................................................................................. 2.5.1-17 1.2.3 Site Stratigraphy .................................................................................... 2.5.1-17 1.2.4 Local Structural Geology....................................................................... 2.5.1-18 1.2.4.1 Site Structural Geology.......................................................................... 2.5.1-20 1.2.5 Site Geological History.......................................................................... 2.5.1-21 1.2.6 Site Engineering Geology ...................................................................... 2.5.1-24 1.3 References for Section 2.5.1 .................................................................. 2.5.1-25 2 VIBRATORY GROUND MOTION ....................................................... 2.5.2-1 2.1 Seismicity................................................................................................. 2.5.2-1 2.1.1 Completeness and Reliability of Earthquake Cataloging ........................ 2.5.2-1 2.1.2 Earthquake History .................................................................................. 2.5.2-2 2.1.3 Seismicity within 50 Miles of the Site..................................................... 2.5.2-4 2.1.4 Earthquakes Felt at the Site ..................................................................... 2.5.2-5 2.2 Geologic Structures and Tectonic Activity.............................................. 2.5.2-9 2.3 Correlation of Earthquake Activity with Geologic Structures or Tectonic Prov-inces ....................................................................................................... 2.5.2-14 2.3.1 Correlation with Geologic Structures .................................................... 2.5.2-14 2.3.2 Correlation with Tectonic Provinces ..................................................... 2.5.2-15 2.4 Maximum Earthquake Potential ............................................................ 2.5.2-16 2.4.1 Maximum Historical Site Intensity........................................................ 2.5.2-16 2.4.2 Maximum Earthquake Potential from Tectonic Province Approach..... 2.5.2-17 2.5 Seismic Wave Transmission Characteristics of the Site........................ 2.5.2-17 2.6 Safe Shutdown Earthquake .................................................................... 2.5.2-18 2.7 Operating Basis Earthquake................................................................... 2.5.2-18 2.8 References for Section 2.5.2 .................................................................. 2.5.2-18 3 SURFACE FAULTING .......................................................................... 2.5.3-1 3.1 Geologic Conditions of the Site............................................................... 2.5.3-1 28/18 2-vi Rev. 31

tion Title Page 3.2 Evidence of Fault Offset .......................................................................... 2.5.3-1 3.2.1 Petrographic Analysis .............................................................................. 2.5.3-3 3.2.2 Clay Mineralogy, Fluid Inclusion Analysis, and Radiometric Dating .... 2.5.3-4 3.2.3 Conclusions.............................................................................................. 2.5.3-7 3.3 Earthquakes Associated with Capable Faults .......................................... 2.5.3-8 3.4 Investigation of Capable Faults ............................................................... 2.5.3-8 3.5 Correlation of Epicenters with Capable Faults ........................................ 2.5.3-8 3.6 Description of Capable Faults.................................................................. 2.5.3-8 3.7 Zone Requiring Detailed Faulting Investigation ..................................... 2.5.3-8 3.8 Results of Faulting Investigation ............................................................. 2.5.3-8 3.9 References for Section 2.5.3 .................................................................... 2.5.3-8 4 STABILITY OF SUBSURFACE MATERIALS AND FOUNDATIONS ..................................................................................... 2.5.4-1 4.1 Geologic Features .................................................................................... 2.5.4-1 4.2 Properties of Subsurface Materials .......................................................... 2.5.4-2 4.2.1 Artificial Fill ............................................................................................ 2.5.4-3 4.2.2 Beach Deposits ........................................................................................ 2.5.4-3 4.2.3 Unclassified Stream Deposits .................................................................. 2.5.4-3 4.2.4 Ablation Till............................................................................................. 2.5.4-4 4.2.5 Basal Till.................................................................................................. 2.5.4-4 4.2.6 Monson Gneiss ........................................................................................ 2.5.4-5 4.3 Exploration............................................................................................... 2.5.4-6 4.4 Geophysical Surveys................................................................................ 2.5.4-6 4.4.1 Onshore Seismic Refraction Survey ........................................................ 2.5.4-7 4.4.2 Offshore Seismic and Bathymetric Survey.............................................. 2.5.4-7 4.4.3 Seismic Velocity Measurements.............................................................. 2.5.4-7 4.5 Excavations and Backfill ......................................................................... 2.5.4-9 4.5.1 Excavation ............................................................................................... 2.5.4-9 4.5.2 Backfill................................................................................................... 2.5.4-11 4.5.3 Extent of Dredging................................................................................. 2.5.4-14 28/18 2-vii Rev. 31

tion Title Page 4.6 Groundwater Conditions........................................................................ 2.5.4-14 4.6.1 Design Basis for Groundwater............................................................... 2.5.4-14 4.6.2 Groundwater Conditions During Construction...................................... 2.5.4-16 4.7 Response of Soil and Rock to Dynamic Loading .................................. 2.5.4-17 4.7.1 Subsurface Material Properties Used in SSI Analysis........................... 2.5.4-18 4.8 Liquefaction Potential............................................................................ 2.5.4-19 4.8.1 Structural Backfill.................................................................................. 2.5.4-19 4.8.2 Basal Tills .............................................................................................. 2.5.4-19 4.8.3 Beach and Glacial Outwash Sands ........................................................ 2.5.4-20 4.8.3.1 Dynamic Response Analysis of Beach and Glacial Outwash Sands ...................................................................................................... 2.5.4-20 4.8.3.2 Liquefaction Analysis of Beach and Glacial Outwash Sands................ 2.5.4-22 4.8.3.3 Liquefaction Analyses of Beach Area Sands using 2-Dimensional Dynamic Response Analysis......................................... 2.5.4-24 4.8.4 Ablation Till........................................................................................... 2.5.4-26 4.8.4.1 Dynamic Response Analysis of Ablation Till ....................................... 2.5.4-26 4.8.4.2 Liquefaction Analysis of Ablation Till .................................................. 2.5.4-27 4.9 Earthquake Design Basis ....................................................................... 2.5.4-28 4.10 Static Stability........................................................................................ 2.5.4-28 4.10.1 Bearing Capacity.................................................................................... 2.5.4-28 4.10.2 Settlement of Structures......................................................................... 2.5.4-29 4.10.3 Lateral Earth Pressures .......................................................................... 2.5.4-30 4.11 Design Criteria ....................................................................................... 2.5.4-30 4.12 Techniques to Improve Subsurface Conditions ..................................... 2.5.4-31 4.13 Structure Settlement............................................................................... 2.5.4-32 4.14 Construction Notes ................................................................................ 2.5.4-32 4.15 References for Section 2.5.4 .................................................................. 2.5.4-33 5 STABILITY OF SLOPES ....................................................................... 2.5.5-1 5.1 Slope Characteristics................................................................................ 2.5.5-1 5.1.1 Shoreline Slope ........................................................................................ 2.5.5-1 28/18 2-viii Rev. 31

tion Title Page 5.1.2 Containment Rock Cut............................................................................. 2.5.5-3 5.2 Design Criteria and Analysis ................................................................... 2.5.5-3 5.2.1 Shoreline Slope ........................................................................................ 2.5.5-3 5.2.2 Containment Rock Cut............................................................................. 2.5.5-6 5.3 Logs of Borings ....................................................................................... 2.5.5-7 5.4 Compacted Fill......................................................................................... 2.5.5-7 5.5 References for Section 2.5.5 .................................................................... 2.5.5-7 6 EMBANKMENTS AND DAMS ............................................................ 2.5.6-1 PENDIX 2.5A- AGE OF TILL AT MILLSTONE POINT .................................... 2.5A-1 PENDIX 2.5B- PETROGRAPHIC REPORTS, FINAL GRADE ..........................2.5B-1 PENDIX 2.5C- MINERALOGICAL ANALYSIS OF MILLSTONE FAULT GOUGE SAMPLES......................................................................................2.5C-1 PENDIX 2.5D- POTASSIUM - ARGON AGE DETERMINATION ................... 2.5D-1 PENDIX 2.5E- SEPARATION OF < 2 FRACTION AND CLAY ANALYSIS OF SAMPLES B, C, D (ESF BUILDING) AND P-1 AND P-2 (PUMPHOUSE).............................................................................2.5E-1 PENDIX 2.5F- DYNAMIC SOIL TESTING ON BEACH SANDS...................... 2.5F-1 PENDIX 2.5G- CONSOLIDATED UNDRAINED TESTS ON BEACH SANDS2.5G-1 PENDIX 2.5H- SEISMIC VELOCITY MEASUREMENTS ................................ 2.5H-1 PENDIX 2.5I- DIRECT SHEAR TESTS ON NATURAL ROCK JOINTS .......... 2.5I-1 PENDIX 2.5J- BORING LOGS..............................................................................2.5J-1 PENDIX 2.5K- SEISMIC SURVEY...................................................................... 2.5K-1 PENDIX 2.5L- SEISMIC AND BATHYMETRIC SURVEY ...............................2.5L-1 PENDIX 2.5M- LABORATORY TEST PROGRAM FOR PROPOSED ADDITIONAL STRUCTURAL BACKFILL SOURCES.....................................2.5M-1 28/18 2-ix Rev. 31

List of Tables mber Title 1 1990 Population and Population Densities Cities and Towns Within 10 Miles of Millstone 2 Population Growth 1960-1990 3 Population Distribution 1985 (0-20 km) 4 Population Distribution Within 10 Miles of Millstone - 1990 Census 5 Population Distribution Within 10 Miles of Millstone - 2000 Projected 6 Population Distribution Within 10 Miles of Millstone - 2010 Projected 7 Population Distribution Within 10 Miles of Millstone - 2020 Projected 8 Population Distribution Within 10 Miles of Millstone - 2030 Projected 9 Population Distribution 1985 (0-80 km) 10 Population Distribution Within 50 Miles of Millstone - 1990 Census 11 Population Distribution Within 50 Miles of Millstone - 2000 Projected 12 Population Distribution Within 50 Miles of Millstone - 2010 Projected 13 Population Distribution Within 50 Miles of Millstone - 2020 Projected 14 Population Distribution Within 50 Miles of Millstone - 2030 Projected 15 Transient Population Within 10 Miles of Millstone - 1991-1992 School Enrollment 16 Transient Population Within 10 Miles of Millstone (Employment) 17 Transient Population Within 10 Miles of Millstone State Parks and Forests (With Documented Attendance) 18 Low Population Zone Permanent Population Distributions 19 Low Population Zone School Enrollment and Employment 20 Metropolitan Areas Within 50 Miles of Millstone 1990 Census Population 21 Population Centers Within 50 Miles of Millstone 22 Population Density* 1985 (0-20 km) 23 Population Density 1985 (0-80 km) 24 Population Density Within 10 Miles of Millstone 1990 (People per Square Mile) 25 Population Density Within 10 Miles of Millstone 2030 (People per Square Mile) 28/18 2-x Rev. 31

mber Title 26 Population Density Within 50 Miles of Millstone 1990 (People per Square Mile) 27 Population Density Within 50 Miles of Millstone 2030 (People per Square Mile) 28 Cumulative Population Density 1985 29 Cumulative Population Density Within 50 Miles of Millstone 1990 (People per Square Mile) 30 Cumulative population Density Within 50 Miles of Millstone 2030 (People per Square Mile) 1 Description of Facilities 2 List of Hazardous Materials Potentially Capable of Producing Significant Missiles 3 Summary of Exposure Distance Calculation 4 Aggregate Probability of Explosion or Violent Rupture Capable of Missile Generation 5 Types of Tank Car Missiles 6 Tank Car Fragment Range (Feet) at 10-Degree Launch Angle 7 Estimated Ignition Probabilities 8 Probability of an Unconfined Vapor Cloud Explosion 1 Monthly, Seasonal, and Annual averages and Extremes of Temperature at Bridgeport, Conn. (1901-1981) 2 Mean Number of Days with Selected Temperature Conditions at Bridgeport, Conn.

(1966-1981) 3 Monthly, Seasonal, and Annual Averages and Extremes of Relative Humidity at Bridgeport, Conn. (1949-1981) 4 Monthly, Seasonal, and Annual Frequency Distributions of Wind Direction at Bridgeport, Conn. (1949-1980) 5 Occurrence of Bridgeport Wind Persistence Episodes within the same 22.5-Degree Sector (1949-1965) 6 Monthly, Seasonal, and Annual Frequency Distributions of Wind Direction at Bridgeport, Conn. (1949-1980) 7 Monthly, Seasonal, and Annual Wind Speed Extremes at Bridgeport, Conn. (1961-1990) 28/18 2-xi Rev. 31

mber Title 8 Mean Number of Days of Thunderstorm Occurrence at Bridgeport, Conn. (1951-1981) 9 Monthly, Seasonal, and Annual Averages and Extremes of Precipitation at Bridgeport, Conn. (1901-June 1982) 10 Estimated Precipitation Extremes for Periods up to 24 Hours and Recurrence Intervals Up to 100 Years 11 Monthly, Seasonal, and Annual Averages and Extremes of Snowfall at Bridgeport, Conn. (1893-June 1990) 12 Monthly, Seasonal, and Annual Averages of Freezing Rain and Drizzle at Bridgeport, Conn. (1949-1980) 13 Average Monthly, Seasonal, and Annual Hours and Frequencies (percent) of Various Fog Conditions (1949-1980) at Bridgeport, Connecticut 14 Monthly and Annual Wind Direction and Speed Distributions for Surface Winds, at Bridgeport, Conn. (1949-1980) 15 Monthly and Annual Wind Direction and Speed Distributions for 33-Foot Winds at Millstone (1974-1981) 16 Comparison of Wind Direction Frequency Distribution by Quadrant at Bridgeport, Conn. and Millstone 17 Comparison of Average Wind Speed by Quadrant at Bridgeport, Conn. and Millstone 18 Occurrence of Wind Persistence Episodes Within the Same 22.5-Degree Sector at Millstone (1974-1981) 19 Millstone Climatological Summary (1974-2000) 20 Comparison of Monthly and Annual Average Dry-Bulb and Dewpoint Temperature Averages at Bridgeport, Conn. and Millstone 21 Comparison of Monthly and Annual Average Relative Humidity Averages at Bridgeport and Millstone 22 Mean Number of Days with Heavy Fog at Bridgeport, Conn. and Block Island, Rhode Island (1951-1981) 23 Wind Direction/Stability Class/Visibility Joint Frequency Distribution at Millstone 24 Persistence of Poor Visibility ( 1 Mile) Conditions at Millstone (Hours) (1974-1981) 28/18 2-xii Rev. 31

mber Title 25 Bridgeport Pasquill Stability Class Distribution (1949-1980) 26 Millstone Stability Class Distribution Using Delta-T for Stability Determination 27 Millstone Stability Class Distribution Using Sigma Theta for Stability Determination 28 Comparison of Pasquill Stability Class Distribution at Bridgeport, Conn. and Millstone 29 Persistence of Stable Conditions (E, F, and G Stabilities) at Millstone (1974-1981) 30 Seasonal and Annual Atmospheric Mixing Depths at Millstone 31 On-site Meteorological Tower Measurements 32 Millstone Meteorological Tower Instrumentation 33 Monthly Summary of Data Recovery Rates/Meteorological System 34 Distances from Release Points to Receptors 1 Connecticut Public Water Supplies within 20 Miles of Millstone 3 2 Maximum Wave Heights Generated by Slow, Medium, and High Speed Storms (Deep-Water Fetch) 3 Maximum Shallow Water Waves (after Refraction) Slow Speed Probable Maximum Hurricane 4 Maximum Shallow Water Waves (after Refraction) Medium Speed Probable Maximum Hurricane 5 Maximum Shallow Water Waves (after Refraction) High Speed Probable Maximum Hurricane 6 Lowest Tides at New London, Connecticut 1938-1974 7 Circulating Water System and Service Water System Heat Loads 8 Dilution Factors and Travel Time

• 9 Category I Structures - Roof Survey 10 Input Data to Program HEC-2 Water Surface Computations 11 Computed Water Surface Elevations at Safety-Related Structures 12 Roof Area and Ponding Level Due to PMP (1)Category I Structures 13 Overflow Length of the Parapet Wall on the Roof Used in PMP Analysis - Category I Structures 28/18 2-xiii Rev. 31

mber Title 1-1 Rock Formations of the Coastal Plain off Southern New England 1-2 Rock Formations of Western Connecticut 1-3 Rock Formations of Eastern Connecticut and Western Rhode Island 1-4 Rock Formations of Central Rhode Island (and not Included in Previous Descriptions) 1-5 Rock Formations in Northern and Eastern Rhode Island and Southern Massachusetts 1-6 Rock Formations of Central Massachusetts 1-7 East of Clinton-Newbury Fault System, Eastern Massachusetts, and New Hampshire 1-8 Descriptions of Lineaments from LANDSAT Photographs (Shown on Figure 2.5.1-10) 2-1 Modified Mercalli (MM) Intensity Scale of 1931 2-2 List of Operating Seismic Stations 2-3 Chronological Catalog of Earthquake Activity within 200 Miles of the Site 2-4 List of Earthquakes within the 50-Mile Radius 3-1 List of Faults 3-2 List of Samples 3-3 List of K/Ar Age Determinations of Fault Gouge 4-1 List of Joints - Final Grade Floors of Structures 4-2 List of Foliations - Final Grade Floors of Structures 4-3 List of Slickensides - Final Grade Floors of Structures 4-4 List of Joints - Final Grade Containment and Engineered Safety Features Building Walls 4-5 List of Foliations - Final Grade Containment and Engineered Safety Features Building Walls 4-6 List of Slickensides - Final Grade Containment and Engineered Safety Features Building Walls 4-7 List of Joints - Final Grade Walls of Structures 4-8 List of Foliations - Final Grade Walls of Structures 28/18 2-xiv Rev. 31

mber Title 4-9 List of Slickensides - Final Grade Walls of Structures 4-10 Rock Compression Test Results 4-11 Direct Shear Test Results From Joint and Foliating Surfaces 4-12 Summary of Static Soil Properties for Beach Sands

• 4-13 Natural Water Contents of Split Spoon Samples 4-14 Foundation Data for Major Structures 4-15 List of Approximate Boring Locations, Ground Elevations, and Groundwater Elevations

• 4-16 Summary of Water Pressure Test Data 4-17 Groundwater Observations 4-18 Factors of Safety Against Liquefaction of Beach Sands 4-19 In-Place Density Test Results on Category I Structural Backfill Beneath the Service Water Intake Pipe Encasement 4-20 In-Place Density Test Results at Control and Emergency Generator Enclosure Buildings 4-23 Emergency Generator Enclosure - Soil Properties with Structure Effects from SHAKE Analysis 4-24 Bearing Capacity of Major Structures 4-25 Results of Two-Dimensional Liquefaction Analysis of Beach Area Sands 28/18 2-xv Rev. 31

List of Figures mber Title 1 General Site Location

-2 General Vicinity 3 Site Layout 4 Site Plan 5 Towns Within 10 Miles 6 1985 Population Distribution 0-20 km 7 Population Sectors for 0-10 Miles 8 Counties within 50 Miles 9 1985 Population Distribution 0-80 km 10 Population Sectors for 0-50 miles 11 Roads and Facilities in the LPZ 12 LPZ Population Sectors Distribution 1 Major Industrial, Transportation and Military Facilities 2 Instrument Landing Patterns at Trumbull Airport 3 Air Lanes Adjacent to Millstone Point 4 New London County-State Highways and Town Roads

-5 Propane Concentration Outside and Inside the Control Room 1 Topography in the Vicinity of Millstone Point 2 Topographical Profiles within 5 Miles of Site 3 Topographical Profiles within 5 Miles of Site 4 Topographical Profiles within 50 Miles of Site (Sheet 1) 5 Topographical Profiles within 50 Miles of Site (Sheet 1) 6 General Topography - 50 Miles (Sheet 1) 7 Meteorological Instrument and Data Quality Assurance Flow Diagram 1 Facilities Located on the Site 2 Public Water Supplies within 20 Miles of Site 3 Locations of Hydrographic Field Survey Stations, June to October 1965 28/18 2-xvi Rev. 31

mber Title 4 Tidal Currents Measured by Essex Marine Laboratory 5 Bottom Profiles Established by Essex Marine Laboratory 6 Frequency of Tidal Flooding at New London, Connecticut 7 Site Grade and Drainage Basins for PMP Runoff Analysis 8 Bottom Profile Along Path of Maximum Surface Winds 9 Coincident Wave and Surge Slow-Speed Probable Maximum Hurricane 10 Coincident Wave and Surge Medium-Speed Probable Maximum Hurricane 11 Coincident Wave and Surge High-Speed Probable Maximum Hurricane 12 Locus of Hurricane Eye, Hurricane Type: Large Radius, Slow Speed of Translation 13 Locus of Hurricane Eye, Hurricane Type: Large Radius, Medium Speed of Translation 14 Locus of Hurricane Eye, Hurricane Type: Large Radius, High Speed of Translation 15 Wave Transects on Long Island Sound 16 Areas Under Effect of Wave Shoaling and Wave Refraction 17 Wave Refraction Diagram, Block Island Sound Grid 18 Wave Refraction Diagram, Millstone Grid, Angle of Approach South 30 Degrees East 19 Wave Refraction Diagram, Millstone Grid, Angle of Approach West 85 Degrees South 20 Wave Refraction Diagram, Millstone Grid, Angle of Approach West 45 Degrees South 21 Wave Refraction Diagram, Millstone Grid, Angle of Approach West 17 Degrees South 22 Topography and Runup Transects, Millstone Location 23 Intake Transect A

-24 Runup Transect B (West) 25 Runup Transect C (East) 26 Wave Clapotis at Intake 27 Inputs to One Dimensional Setdown Model 28/18 2-xvii Rev. 31

mber Title 28 Large Radius, Probable Maximum Hurricane Isovel Field 29 Large Radius, Slow Speed of Translation Time Variant Wind Field - Millstone 30 Setdown Versus Wind Speed 31 Boundary of the Modeled Area 32 Onsite Well Locations 33 Probable Seepage Path From Boron Recovery Tank and Waste Disposal Building to Long Island Sound 34 Scupper Details - Control, Hydrogen Recombiner, and Containment Enclosure Buildings 35 Roof Plug Sealing Detail - Hydrogen Recombiner Building 36 Hatch Cover Details - Circulating Water Pumphouse Service Water Pump Cubicle 37 Hatch Cover Details - Control Building Mechanical Room 1-1 Regional Physiographic Map 1-2 Regional Pre-Pleistocene Sediments of the Continental Margin 1-3 Site Surficial Geology 1-4 Regional Geologic Map 1-5 Regional Geologic Section 1-6 Regional Tectonic Map 1-7 Stratigraphic Correlation Chart for the Site and Surrounding Region) 1-8 Regional Stratigraphic Correlation Chart (Sheet 1) 1-9 LANDSAT Photographs of Connecticut, Rhode Island, Southern Massachusetts, and Eastern New York 1-10 Lineament Map from LANDSAT Photographs 1-11 Regional Aeromagnetic Map 1-12 Regional Bouguer Gravity Map 1-13 Site Bedrock Geology 1-14 Tectonic Map of Eastern Connecticut 1-15 Contour Diagram of Poles to Foliation Planes - Final Grade 1-16 Contour Diagram of Poles to Joint Planes - Final Grade 28/18 2-xviii Rev. 31

mber Title 1-17 Contour Plot of Bearing and Plunge of Slickensides - Final Grade 1-18 Generalized Location of Faults 2-1 Location of Seismic Stations 2-2 Epicenters of Earthquakes within 200-Mile Radius 2-3 Location of Earthquakes within the 50-Mile Radius 2-4 Isoseismal Map, Earthquake of November 9, 1727 2-5 Isoseismal Map, Earthquake of November 18, 1755 2-6 Isoseismal Map, Earthquake of May 16, 1791 2-7 Isoseismal Map, Earthquake of August 10, 1884 2-8 Isoseismal Map, Earthquake of March 1, 1925 (February 28, 1925 EST) 2-9 Isoseismal Map, Earthquakes of December 20 and 24, 1940 2-10 Tectonic Provinces 3-1 T-2 Fault Zone, Final Excavation Grade - Northern Section 3-2 T-2 Fault Zone, Final Excavation Grade - Southern Section 3-3 T-3 Fault Zone, Final Excavation Grade 4-1 Geologic Map of Final Grade, Service Water Line Walls - East 4-2 Geologic Map of Final Grade, Service Water Line Walls - West 4-3 Geologic Map of Final Grade, South Wall of Discharge Tunnel 4-4 Geologic Map of Final Grade, North Wall of Discharge Tunnel 4-5 Geologic Map of Final Grade, East Wall of Discharge Tunnel 4-6 Geologic Map of Final Grade, Floors of Structures 4-7 Geologic Map of Final Grade, Service Water Line Floor - West 4-8 Geologic Map of Final Grade, Pumphouse Floor 4-9 Geologic Map of Final Grade, Service Water Line Floor - East 4-10 Geologic Map of Final Grade, Southeast Quadrant of Containment Walls 4-11 Geologic Map of Final Grade, Southwest Quadrant of Containment Walls 4-12 Geologic Map of Final Grade, Northwest Quadrant of Containment Walls 4-13 Geologic Map of Final Grade, Northeast Quadrant of Containment Walls 28/18 2-xix Rev. 31

mber Title 4-14 Geologic Map of Final Grade, Engineered Safety Features, Building Sump Walls 4-15 Geologic Map of Final Grade, Auxiliary Building Pipe Tunnel Pit Walls 4-16 Geologic Map of Final Grade, North Wall of Excavation 4-17 Geologic Map of Final Grade, Northeast and Southeast Pumphouse Walls 4-18 Geologic Map of Final Grade Engineered Safety Features Building Wall 4-19 Geologic Map of Final Grade Discharge Tunnel Floor 4-20 Geological Map of Final Grade Discharge Tunnel Floor 4-21 Geological Map of Final Grade North Wall of Discharge Tunnel 4-22 Geological Map of Final Grade South Wall of Discharge Tunnel 4-23 Geologic Map of Final Grade Discharge Tunnel Floor 4-24 Geologic Map of Final Grade Discharge Tunnel Floor 4-25 Geologic Map of Final Grade West Wall of Discharge Tunnel 4-26 Geologic Map of Final Grade East Wall of Discharge Tunnel 4-27 Geologic Map of Final Grade Discharge Weir Rock Face 4-28 Corrected Blow Count Plot, Pumphouse Area Sands, Onshore Boring Composite 4-29 Corrected Blow Count Plot, Pumphouse Area Sands, Borings P1 to P8 Composite 4-30 Grain Size Distribution Curves (Sheet 1) 4-31 Boring Location Plan 4-32 Plot Plan Showing Locations of the Borings and the Geologic Sections 4-33 Geologic Profile, Sections A-A', B-B' 4-34 Geologic Profile, Sections C-C', D-D', E-E' 4-35 Geologic Profile, Sections F-F" and G-G' 4-36 Top of Basal Till Contour Map 4-37 Groundwater Contour Map 4-38 Groundwater Observations in Boreholes 4-39 Bedrock Surface Contour Map 4-40 General Excavation Plan 4-41 Shorefront and Dredging Plan 28/18 2-xx Rev. 31

mber Title 4-42 Modulus vs Effective Confining Pressure, Structural Fill 4-43 Lateral Pressure Distribution 4-44 Gradation Curves for Category I Structural Fill 4-45 K2 vs Shear Strain for Beach Sands 4-46 Earthquake Induced Shear Stresses in Beach Sands 4-47 Cyclic Stress Ratio vs Confining Pressure for Beach Sands 4-48 Cyclic Stress Ratio vs Penetration Resistance of Sand 4-49 Factor of Safety Against Liquefaction of Beach Sands 4-50 Idealized Soil Profile Liquefaction Analysis of Ablation Till Under Discharge Tunnel 4-51 Geologic Profile, Section H-H

4-52 Geologic Profile, Section I-I

4-53 Location of Field Density Tests - Service Water Intake Line 4-54 Location of Field Density Test - Emergency Generator Enclosure and Control Building 4-55 Geologic Profile, Section J-J' 4-56 Geologic Profile, Section K-K' 4-57 Grain Size Distribution Curves - Pumphouse Area Outwash Sands (Sheet 1) 4-58 Equivalent Numbers of Uniform Stress Cycles Based on Strongest Components of Ground Motion 4-59 Plan of Settlement Monitoring Benchmark Locations 4-60 Control Building Settlement (Sheet 1) 4-61 Emergency Generator Enclosure Settlement 4-62 .Solid Waste Building Settlement 4-63 Liquid Waste Building Settlement 4-64 Fuel Building Settlement 4-65 Geologic Profile Section L-L' 4-66 Geologic Profile Section M-M' 4-67 Geologic Profile Section N-N' 28/18 2-xxi Rev. 31

mber Title 4-68 Geologic Profile Section O-O' 4-69 Geologic Profile Section P-P' 4-70 Geologic Profile Section Q-Q' 4-71 Geologic Profile Section R-R' 4-72 Soil-Structure Interaction Emergency Generator Enclosure 4-73 Shear Modulus Curve Type 2 Soil (Structural Backfill and Basal Till) 4-74 Damping Curve Type 2 Soil (Structural Backfill and Basal Till) 4-75 Shorefront Profile Used in Liquefaction Analyses 5-1 Section through Shorefront 5-2 Typical Wedge Geometry 5-3 Design Loads for Ring Beam 5-4 Shorefront Slope Stability Section - Sloping Rock Profile 5-5 Summary of CIU Test Results - Beach Area Outwash Sands 5-6 Potential Failure Wedges West Side of Containment Excavation 5-7 Rock Surface Near North Edge of Main Steam Valve Building 28/18 2-xxii Rev. 31

s section contains information on the geological, seismological, hydrological, meteorological, demographic characteristics of the Millstone site and vicinity to show the adequacy of the site m the safety viewpoint.

GEOGRAPHY AND DEMOGRAPHY 1 SITE LOCATION AND DESCRIPTION 1.1 Specification of Location Millstone site is located in the Town of Waterford, New London County, Connecticut, on the h shore of Long Island Sound. The 524-acre site occupies the tip of Millstone Point between ntic Bay on the west and Jordan Cove on the east and is situated 3.2 miles west-southwest of w London and 40 miles southeast of Hartford.

Millstone 3 containment structure is located immediately north of Millstone 1 and 2. The graphical coordinates of the centerline of each reactor are as follows:

Unit Latitude and Longitude Northing and Easting Millstone 3 N 41° 18'41" N 174, 710 W 72° 10'06" E 759, 770 Millstone 2 N 41° 18'35" N 174, 090 W 72° 10'06" E 759, 825 Millstone 1 N 41° 18'32" N 173, 800 W 72° 10'04" E 759, 965 1.2 Site Area site is owned by two tenants in common: Connecticut Light & Power Company and Western ssachusetts Electric Company, except for that portion of land designated for the Millstone lear Power Station, Unit 3 site which is owned by its participants in ownership. Figures 2.1-1 ugh 2.1-4 identify the site.

1.3 Boundaries for Establishing Effluent Release Limits lstone Point was thoroughly investigated for acceptability as a nuclear power plant site and nd to be suitable by the Atomic Energy Commission before the Millstone 1 Construction mit was issued in 1966, before the Millstone 1 Operating License DPR-21 was granted in 0, prior to the issuance of the Millstone 2 Construction Permit in December 1970, and prior to Millstone 2 Operating License DPR-65 in August 1976.

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exclusion area, as described in Section 2.1.2, is considered the restricted area. The restricted has been conspicuously posted and administrative procedures, including periodic patrolling, e been imposed to control access to the area. For the purpose of radiological dose assessment ccidents, the exclusion area boundary (EAB) was considered the actual site boundary for rland sectors, except in the Fox Island/discharge channel area on the south end of the site. For water sectors, the nearest land site boundary distance was used.

EAB boundary shown in Figure 2.1-3 is an example for a Millstone 3 containment release.

actual EAB distance varies as a function of the release point. The actual distances used for h sector for each release point are given inTable 2.3-34.

significant normal releases from Millstone 3 are discharged to the atmosphere via the lstone stack or through various Millstone 3 vents. The distance from the Millstone stack to the rest residential property boundary in the Millstone Point Colony development (Point A on ure 2.1-3) is approximately 2,415 feet. This development, adjacent to the eastern site ndary, consists of single family homes on 104 half-acre lots. It was developed from 1951 to present.

Colony development has its own beach and boat docking facility, shown as Recreation Area Figure 2.1-3, extending westward along Jordan Cove. The land is owned by Mr. H. Gardiner, who permits residents to use it for a fee of $1.00 per year.

land of the Colony development, the private beach, and the Millstone site were all originally ed by Mr. Gardiner. One of the conditions of the sale of the site to the Hartford Electric Light mpany and the Connecticut Light and Power Company was that permanent dwellings would er be permitted in the beach area. Because of this restriction, normal release doses are ulated at Point A rather than at the nearest point on the site boundary. The distance from the lstone 3 turbine building to Point A is approximately 2,750 feet. Point A is northeast of both Millstone 3 turbine building and the Millstone stack. The distance to the nearest land for each or for each release point used in dose calculations for normal effluents is given in tion 2.3.4.2.

2 EXCLUSION AREA AUTHORITY AND CONTROL 2.1 Authority Millstone Nuclear Power Station site is owned by Dominion Nuclear Connecticut, Inc.

C). Figures 2.1-1 through 2.1-4 identify the site.

exclusion area is equivalent to the area within the site boundary which is identified on ure 2.1-3. DNC, the operating company for all three units at the Millstone site, has the trolling authority for the exclusion area. Accordingly, DNC has the authority to determine all vities within the exclusion area.

28/18 2.1-2 Rev. 31

exclusion area is wholly owned as indicated above; DNC as the operating company has plete control of activities within the exclusion area, except for the passage of trains along the vidence & Worcester (P&W)/Amtrak Railroad track which runs east-west through the site.

ensure the safety of people within the exclusion area during an emergency, an emergency plan ction 13.3) for the site has been prepared. The plan includes provisions for alarms both inside outside buildings and delineates the evacuation routes and assembly areas to be used. The ty of people living or working adjacent to the exclusion area is protected during emergencies ording to the procedures outlined in the emergency plan. The State of Connecticut Emergency n also provides for the control of activities in that portion of the exclusion area extending hore through a written agreement between the Applicants and the U.S. Coast Guard at their ion in New London, Connecticut.

owners have encouraged public use of portions of the site. Ownership rights have not, ever, been relinquished, and the owners can, and have provision to, fulfill their obligations h respect to 10 CFR 20, Standards for Protection Against Radiation.

ortion of the exclusion area is leased to the Town of Waterford for public recreation and is d primarily for soccer and baseball games. Figure 2.1-3 shows the general location of these vities. No attempt is made to restrict the number of persons using these facilities. Estimates of imum attendance indicate that about 2,000 visitors could be within the exclusion area at any time at the soccer and baseball fields. The Emergency Plan provides for removal of the tors on site. The number and configuration of roads and highways assure ready egress from areas described above (Figures 2.1-2, 2.1-3 and 2.1-4).

2.3 Arrangements for Traffic Control uld the need ever arise, provisions to enforce traffic control have been made through the necticut State Police, as described in the Millstone Nuclear Power Station Emergency Plan ction 13.3).

2.4 Abandonment or Relocation of Roads August 30, 1965, a town meeting was called to close and discontinue roads to Millstone Point.

April 30, 1966, when the 8-month time for public appeal had passed, discontinuance of lstone Road became effective.

May 31, 1966, the Connecticut Public Utility Commission gave approval to construct a new ted access highway with a new bridge being built to highway specification 20-44 over the ent ConRail/Amtrak rail line approximately 305 meters (1,000 feet) east of Old Millstone d Bridge No. 45.07.

28/18 2.1-3 Rev. 31

shifted to the new limited access highway, which is shown as New Millstone Road on ure 2.1-3.

further road closing is necessary.

2.5 Independent Spent Fuel Storage Installation (ISFSI) ated on the east side of the site is an area that has been developed for an Independent Spent l Storage Installation (ISFSI). The licensing basis of the ISFSI includes the Transnuclear ety Analysis Report (SAR), Certificate of Conformance (C of C) No. 1004, Safety Evaluation ort (SER), and the 10 CFR 72.212 report which details compliance of the Millstone site with requirements of the SAR, C of C and SER. The general location of the area is south of the tchyard, west of the Millstone access road between the switchyard and the crossing of the n rail spur, north of the Main Stack. The approximate location is shown in Figures 2.1-3 and

4. This area consists of reinforced concrete storage pads and approach aprons.

eavy haul road is defined between the Unit 3 Railroad Canopy and the ISFSI area. This haul has been evaluated to adequately support the loads imparted by the ISFSI equipment.

3 POPULATION DISTRIBUTION 3.1 Population Distribution within 10 miles total 1990 population within 10 miles of the station was estimated to be 120,443. This ulation is expected to increase to about 129,846 people by the year 2000 and to a total of roximately 142,277 people by the year 2030 (New York State Department of Economic elopment, 1989 (Reference 2.1-1); State of Connecticut Office of Policy and Management, 1 (Reference 2.1-2); US Department of Commerce, Bureau of the Census, 1990 Census of ulation (Reference 2.1-3). The 10 mile area includes portions of, or all of, New London and dlesex Counties in Connecticut and a small portion of Suffolk County on Fishers Island which art of the town of Southold, New York. Figure 2.1-5 shows counties and towns within the 10 e area. Town populations and population densities are provided in Table 2.1-1.

Town of Waterford, in which Millstone 3 is located, contained a total population of 17,930 ple in 1990 at an average density of 547 people per square mile (US Department of Commerce eau of the Census 1991) (Reference 2.1-3). The population growth of Waterford was small h the 1990 total representing only a 0.5 percent increase over its 1980 population. Compared to ns immediately surrounding it, with the exception of New London, Waterford had the lowest ease in population between 1980 and 1990 (US Department of Commerce Bureau of the sus, 1991 (Reference 2.1-3)).

erford's growth has been consistently slowing down over the past 30 years, as shown in le 2.1-2. This slow growth is projected by state demographers to continue at a low rate ugh the year 2000, at which time the population is expected to reach 18,480. After that, it is 28/18 2.1-4 Rev. 31

ulation Projections, 1991 (Reference 2.1-2)). Population distribution by sector for the area hin 20 Km of Millstone 3 for 1985 (the expected first year of operation) is shown in Table 2.1-nd Figure 2.1-6 (Office of Policy and Management, State of Connecticut, Population jections to the Year 2000, February 1980 (Reference 2.1-4)). Population distribution by sector the area within 10 miles of Millstone 3 is shown for the years 1990, 2000, 2010, 2020 and 0 in Tables 2.1-4 through 2.1-8, which are keyed to the population sectors identified in ure 2.1-7.

ulation distribution within 10 miles is based on 1990 US Census data by Census Block ference 2.1-3). The population within a Census Block was assumed to be distributed evenly r its land area, unless USGS 7.5 minute quadrangle maps indicated the population to be centrated in only one portion of the Block. The proportion of each Block area in each grid or was determined and applied to the Block total population, yielding the population in each sector. Population projections, by municipality, supplied by Connecticut's Office of Policy Management provided growth factors for projection of populations (State of Connecticut ice of Policy and Management, Interim Population Projections, 1991 (Reference 2.1-2)).

3.2 Population Distribution within 50 Miles area within 50 miles of Millstone 3 includes portions, or all, of eight counties in Connecticut, counties in Rhode Island and one county in New York. Figure 2.1-8 shows counties and ns within the 50 mile area. In 1990, the 50-mile area contained approximately 2,835,159 ple (U.S. Department of Commerce), 1990 Census of Population and Housing (Reference 2.1-This population is projected to increase to about 3,223,654 by the year 2030 (Connecticut ice of Policy and Management, 1991 (Reference 2.1-2); New York State Department of nomic Development, 1989 (Reference 2.1-1); Rhode Island Department of Administration, 9 (Reference 2.1-6); US Department of Commerce, 1990 Census of Population and Housing, 1 (Reference 2.1-5). Population distribution by sector for the area within 80 Km of Millstone r 1985 (the expected first year of operation) is shown in Table 2.1-9 and Figure 2.1-9 (Office Policy and Management, State of Connecticut, Population Projections to the Year 2000, ruary 1980 (Reference 2.1-4); Economic Development Board, State of New York, Population jections, 1978 (Reference 2.1-7); Rhode Island Statewide Planning Program, Population jections, Technical Paper No. 83, Revised April 1979 (Reference 2.1-8)). Population ribution by sector for the area within 50 miles of Millstone 3 is shown for the years 1990, 0, 2010, 2020 and 2030 in Tables 2.1-10 through 2.1-14, which are keyed to the population ors identified in Figure 2.1-10.

ulation distribution and projections within the 50 mile region surrounding Millstone 3 were ulated based on population by municipalities and were assigned to sectors based on land area cation. Projections for the 50 mile area were based on country-wide projections.

28/18 2.1-5 Rev. 31

sonal population increases resulting from an influx of summer residents total approximately

00. However, many of the beaches and recreation facilities in the area are used by residents, therefore, do not represent any increase in population but instead a slight shift in population.

re are, however, a number of schools, industries, and recreation facilities which create daily seasonal variations in sector populations. Tables 2.1-15 through 2.1-17 show annular sector ulation variations resulting from school enrollments, industrial employment, and recreation lities (with documented attendance).

3.4 Low Population Zone low population zone (LPZ) surrounding Millstone 3 encompasses an area within a radial ance of about 2.4 miles. The distance was chosen based on the requirements of CFR 100.11. Figure 2.1-11 shows topographical features, transportation routes, facilities, and itutions within the LPZ.

LPZ contained approximately 9,846 people in 1990, with an average density of 545 people square mile. By the year 2030, the LPZ population is projected to increase to about 11,629, or verage density of 643 people per square mile (US Department of Commerce, Bureau of the sus, 1991 (Reference 2.1-3); Connecticut Office of Policy and Management, 1991 ference 2.1-2); US Geological Survey (Reference 2.1-9)). The LPZ population distribution for 0 and 2030 is shown in Table 2.1-18. Table 2.1-19 shows the 1991-1992 school and loyment distribution within the LPZ. Both tables are keyed to Figure 2.1-12.

ly and seasonal variations due to transient population are minimal within the LPZ. Several ches are located within the area; however, they are predominantly used by local residents and erally have no facilities for parking or accommodation of large groups. Three schools, Great k Elementary and Southwest Elementary in Waterford, and Niantic Elementary in East Lyme, located within the LPZ. Major employment consists of the Connecticut National Guard lity and Hendel Petroleum. The New London Country Club is also located within the LPZ.

3.5 Population Center closest population center to Millstone 3 (as defined by 10 CFR 100 to contain > 25,000 dents) is the City of New London which contained a 1990 population of 28,540 people at an rage population density of 5,189 people per square mile (US Department of Commerce eau of the Census 1991). The distance between Millstone 3 and the city's closest corporate ndary is about 3.3 miles to the northeast, just beyond the minimum distance requirement set 0 CFR 100.

city of New London is part of the New London - Norwich Metropolitan Statistical Area A) which contained an estimated 266,819 people in 1990 (US Department of Commerce eau of the Census, 1991 (Reference 2.1-3). An MSA is an area, defined by the US Census eau, that always contains a city or cities of specified population, with contiguous cities or 28/18 2.1-6 Rev. 31

region within 50 miles of Millstone 3 includes portions, or all, of 11 MSAs. The populations hese areas are shown in Table 2.1-20.

re were 38 population centers within 50 miles of Millstone 3, containing 25,000 or more ple in 1990. They are listed in Table 2.1-21 with the populations indicated.

3.6 Population Density population of the area within 50 miles of Millstone was approximately 2,835,159 in 1990, h an average density of 361 people per square mile. This density is lower than the NRC parison figure of 500 people per square mile (NRC Regulatory Guide 1.70, Revision 3).

hin 30 miles of Millstone, the population density is considerably less, at an average of 189 ple per square mile. By 2030, the 50-mile population is projected to increase to 3,223,654 or verage population density of about 410 people per square mile, considerably lower than the C comparison figure for end-year plant life of 1,000 people per square mile. Within 30 miles, average density will be 223 persons per square miles by the year 2030. Population densities by or for the areas within 20 km and 80 km of Millstone 3 for 1985 (the expected first year of ration) are shown in Table 2.1-22 and 2.1-23, respectively. Population densities by sector for 0 and 2030 are shown for within 10 miles of Millstone in Tables 2.1-24 and 2.1-25 ectively, which are keyed to Figure 2.1-7, and for within 50 miles of Millstone in Tables 2.1-d 2.1-27, respectively, which are keyed to Figure 2.1-10. Cumulative population densities for areas within 80 km of Millstone 3 for 1985 (the expected first year of operation) are shown in le 2.1-28. Cumulative population densities 1990 and 2030 are shown in Tables2.1-29 and 2.1-espectively.

4 REFERENCES FOR SECTION 2.1 1 New York State Department of Economic Development, Interim County, MSA and Region Projections, 1980-2010, 1989.

2 Connecticut Office of Policy Management, Interim Population Projections Series 91.1, 1991.

3 US Department of Commerce, Bureau of the Census, 1990 Census of Population, P.L.94-171 Counts by Census Block, 1991.

4 Office of Policy and Management, Comprehensive Planning Division, State of Connecticut, Population Projections for Connecticut Municipalities and Regions to the year 2000, February, 1980.

5 US Department of Commerce, Bureau of the Census, 1990 Census of Population and Housing - Connecticut, 1990 CPH-1-8, 1991.

28/18 2.1-7 Rev. 31

7 Economic Development Board, State of New York, Official Population Projections for New York State Counties, 1978.

8 Rhode Island Statewide Planning Program, Rhode Island Population Projections by County, City and Town, Technical Paper No. 83, Revised April 1979.

9 U.S. Geological Survey, 7.5-Minute Quadrangle maps.

10 US Nuclear Regulatory Commission, Regulatory Guide 1.70, Revision 3.

PPORTING REFERENCES ssachusetts Institute for Social and Economic Research, Revised Projections of the Population Massachusetts Cities and Towns to the Year 2000, 1991.

Department of Commerce, Bureau of the Census, State and Metropolitan Area Book 1991, a istical Abstract Supplement, 1991.

Department of Commerce, Bureau of the Census, 1990 Census P.L.94-171 Counts by nicipality - New York, 1991.

Department of Commerce, Bureau of the Census, 1990 Census P.L.94-171 Counts by nicipality - Rhode Island, 1991.

Department of Commerce, Bureau of the Census, Number of Inhabitants: Connecticut, PC(1)-

1971; PC80-1-A8, 1981.

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TOWNS WITHIN 10 MILES OF MILLSTONE 1990 POPULATION 1990 POPULATION DENSITY 1980 - 1990 MUNICIPALITY TOTAL (People/Square Mile) CHANGE (%)

st Lyme 15,340 451 10.6 oton (including City) 45,144 1,442 9.9 dyard 14,913 391 8.6 me 1,949 61 7.0 ntville 16,673 397 1.3 w London 28,540 5,189 -1.0 d Lyme 6,535 283 6.1 d Saybrook 9,552 637 2.9 terford 17,930 547 0.5 uthold, New York 19,836 394 3.5 shers Island)

TES:

ed on 1990 US Census of Population and Housing.

udes total 1990 population of all municipalities totally or partially within 10 miles of the site.

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TOTAL POPULATION  % CHANGE MUNICIPALITY 1960 1970 1980 1990 1960-1970 1970-1980 1980-199 East Lyme 6,782 11,399 13,870 15,340 68.1 21.7 10.6 Groton 29,937 38,523 41,062 45,144 28.7 6.6 9.9 Ledyard 5,395 14,558 13,735 14,913 169.8 -5.7 8.6 Lyme 1,183 1,484 1,822 1,949 25.4 22.8 7.0 Montville 7,759 15,662 16,455 16,673 101.9 5.1 1.3 New London 34,182 31,630 28,842 28,540 -7.5 -8.8 -1.0 Old Lyme 3,068 4,964 6,159 6,535 61.8 24.1 6.1 Old Saybrook 5,274 8,468 9,287 9,552 60.6 9.7 2.9 Waterford 15,391 17,227 17,843 17,930 11.9 3.6 0.5 SOURCES:

1980 Census of Population, Number of Inhabitants, Connecticut, PC80-1-A8, 12/81.

1970 Census of Population, Number of Inhabitants, Connecticut, PC(1)-A8, 4/71.

1980 Final Population and Housing Counts, Connecticut, PHC80-V-8, 3/81.

1990 Census of Population and Housing, Connecticut, CPH-1-8, 7/91.

06/28/18 2.1-10 Rev. 31

Distance (km) rection 0-2 2-4 4-6 6-8 8-10 10-20 Total 152 1,306 1,341 136 585 9,463 12,983 E 12 1,186 1,958 584 2,819 9,676 16,235 326 1,250 763 15,113 8,239 13,641 39,332 E 267 513 3,063 3,559 8,491 19,484 35,377 366 896 1,169 976 534 4,816 8,757 E 0 127 0 0 0 1,184 1,311 0 0 0 0 0 0 0 E 0 0 0 0 0 0 0 0 0 0 0 0 0 0 W 0 0 0 0 0 340 340 0 25 81 0 0 0 106 SW 0 1,183 193 757 1,960 2,309 6,402 0 727 1,102 411 428 8,463 11,131 NW 0 1,298 1,266 90 140 3,430 6,224 W 0 852 799 426 418 3,758 6,253 W 311 694 902 795 503 6,321 9,526 tal 1,434 10,057 12,637 22,847 24,117 82,884 153,976 28/18 2.1-11 Rev. 31

Distance to Plant Sector 0-1 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8-9 9-10 T N 16 722 866 784 116 213 542 209 536 1,717 5,7 NNE 13 359 1,146 1,978 1,861 1,622 1,666 2,242 2,192 3,142 16, NE 165 455 839 3,888 10,584 7,752 8,164 8,129 911 1,961 42, ENE 22 455 292 4,963 971 7,186 3,748 3,047 1,008 2,662 24, E 0 636 413 1,804 193 552 0 63 1,434 904 5,9 ESE 0 143 36 0 0 0 0 0 115 214 508 SE 0 0 0 0 0 0 0 0 0 0 0 SSE 0 0 0 0 0 0 0 0 0 0 0 S 0 0 0 0 0 0 0 0 0 0 0 SSW 0 0 0 0 0 0 0 0 0 0 0 SW 0 0 14 0 0 0 0 0 0 0 14 WSW 0 0 489 91 86 312 472 158 0 74 1,6 W 0 178 1,061 1,014 440 763 475 562 881 408 5,7 WNW 0 476 1,165 1,964 346 239 211 1,654 509 417 6,9 NW 0 634 873 1,192 1,140 644 599 101 209 81 5,4 NNW 148 314 892 522 646 918 221 429 456 314 4,8 Total 364 4,372 8,086 18,200 16,383 20,201 16,098 16,594 8,251 11,894 120 06/28/18 2.1-12 Rev. 31

Distance to Plant Sector 0-1 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8-9 9-10 TO N 18 778 932 845 126 230 582 225 578 1,852 6,16 NNE 14 387 1,234 2,131 2,006 1,749 1,796 2,415 2,366 3,389 17,4 NE 179 489 905 4,191 11,415 8,359 8,802 8,765 983 2,115 46,2 ENE 24 492 314 5,352 1,045 7,746 4,041 3,285 1,087 2,870 26,2 E 0 685 444 1,944 208 597 0 68 1,546 975 6,46 ESE 0 154 39 0 0 0 0 0 125 233 551 SE 0 0 0 0 0 0 0 0 0 0 0 SSE 0 0 0 0 0 0 0 0 0 0 0 S 0 0 0 0 0 0 0 0 0 0 0 SSW 0 0 0 0 0 0 0 0 0 0 0 SW 0 0 14 0 0 0 0 0 0 0 14 WSW 0 0 528 98 92 336 509 169 0 78 1,81 W 0 192 1,144 1,093 473 821 513 606 950 436 6,22 WNW 0 514 1,255 2,118 373 258 227 1,783 548 448 7,52 NW 0 684 940 1,285 1,229 695 646 108 226 88 5,90 Total 393 4,715 8,710 19,621 17,663 21,781 17,354 17,886 8,900 12,823 129, 06/28/18 2.1-13 Rev. 31

Distance to Plant Sector 0-1 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8-9 9-10 TO N 18 803 961 871 129 237 600 230 595 1,908 6,3 NNE 14 399 1,272 2,197 2,068 1,804 1,853 2,492 2,437 3,495 18, NE 184 504 930 4,321 11,767 8,617 9,074 9,036 1,013 2,180 47, ENE 25 507 324 5,518 1,078 7,988 4,166 3,387 1,119 2,960 27, E 0 707 458 2,005 215 616 0 70 1,593 1,005 6,6 ESE 0 159 41 0 0 0 0 0 138 255 593 SE 0 0 0 0 0 0 0 0 0 0 0 SSE 0 0 0 0 0 0 0 0 0 0 0 S 0 0 0 0 0 0 0 0 0 0 0 SSW 0 0 0 0 0 0 0 0 0 0 0 SW 0 0 15 0 0 0 0 0 0 0 15 WSW 0 0 545 102 95 346 525 175 0 79 1,8 W 0 198 1,179 1,126 488 847 530 625 981 443 6,4 WNW 0 529 1,294 2,184 385 266 234 1,838 566 461 7,7 NW 0 705 969 1,325 1,267 716 666 111 232 90 6,0 NNW 163 350 992 582 718 1,021 245 476 506 350 5,4 Total 404 4,861 8,980 20,231 18,210 22,458 17,893 18,440 9,180 13,226 133 06/28/18 2.1-14 Rev. 31

Distance to Plant Sector 0-1 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8-9 9-10 TO N 19 828 990 899 133 243 620 236 613 1,968 6,54 NNE 14 411 1,310 2,264 2,132 1,860 1,909 2,569 2,513 3,602 18,5 NE 188 519 960 4,455 12,134 8,885 9,355 9,318 1,044 2,247 49,1 ENE 25 523 333 5,689 1,110 8,236 4,296 3,492 1,151 3,052 27,9 E 0 728 472 2,067 222 635 0 72 1,642 1,036 6,87 ESE 0 162 41 0 0 0 0 0 144 268 615 SE 0 0 0 0 0 0 0 0 0 0 0 SSE 0 0 0 0 0 0 0 0 0 0 0 S 0 0 0 0 0 0 0 0 0 0 0 SSW 0 0 0 0 0 0 0 0 0 0 0 SW 0 0 15 0 0 0 0 0 0 0 15 WSW 0 0 562 105 98 356 541 180 0 80 1,92 W 0 205 1,216 1,161 504 874 546 644 1,011 450 6,61 WNW 0 544 1,336 2,252 398 274 242 1,895 583 476 8,00 NW 0 727 998 1,365 1,308 738 687 114 239 93 6,26 NNW 168 361 1,023 600 738 1,053 253 491 523 362 5,57 Total 414 5,008 9,256 20,857 18,777 23,154 18,449 19,011 9,463 13,634 138 06/28/18 2.1-15 Rev. 31

Distance to Plant Sector 0-1 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8-9 9-10 TOT N 19 855 1,021 927 136 250 638 242 631 2,027 6,74 NNE 14 425 1,351 2,334 2,196 1,916 1,968 2,650 2,590 3,712 19,15 NE 193 535 990 4,592 12,510 9,160 9,644 9,606 1,075 2,315 50,62 ENE 26 539 343 5,866 1,145 8,492 4,428 3,598 1,188 3,147 28,77 E 0 751 487 2,132 229 655 0 73 1,692 1,068 7,08 ESE 0 167 43 0 0 0 0 0 151 281 64 SE 0 0 0 0 0 0 0 0 0 0 SSE 0 0 0 0 0 0 0 0 0 0 S 0 0 0 0 0 0 0 0 0 0 SSW 0 0 0 0 0 0 0 0 0 0 SW 0 0 15 0 0 0 0 0 0 0 1 WSW 0 0 580 108 101 366 558 185 0 81 1,97 W 0 212 1,254 1,197 520 901 561 663 1,043 458 6,80 WNW 0 560 1,377 2,323 409 281 249 1,956 602 490 8,24 NW 0 748 1,029 1,407 1,349 761 708 116 246 95 6,45 NNW 174 371 1,055 618 761 1,085 261 507 539 374 5,74 Total 426 5,163 9,545 21,504 19,356 23,867 19,015 19,596 9,757 14,048 142,27 06/28/18 2.1-16 Rev. 31

Distance (km)

Direction 0-20 20-40 40-60 60-80 Total 12,983 24,346 48,558 22,966 108,853 E 16,235 48,297 28,695 42,400 135,627 39,332 13,723 24,719 224,759 302,533 E 35,377 27,604 33,732 117,868 214,581 8,757 14,326 8,982 122 32,187 E 1,311 0 674 0 1,985 0 2,038 0 0 2,038 E 0 4,457 0 0 4,457 0 8,906 2,657 0 11,563 W 340 8,979 21,915 2,602 33,836 106 5,869 20,269 210,804 237,048 SW 6,402 554 0 20,268 27,224 11,131 33,197 98,419 361,418 504,165 NW 6,224 16,353 124,272 276,965 423,814 W 6,253 12,395 102,235 483,164 604,047 W 9,526 13,152 55,071 129,100 206,849 tal 153,977 234,196 570,198 1,892,436 2,850,807 28/18 2.1-17 Rev. 31

1990 CENSUS Distance to Plant Sector 0-10 10-20 20-30 30-40 40-50 Total 5,721 22,283 26,357 32,610 18,658 105,629 E 16,221 34,824 23,730 27,465 35,598 137,838 42,848 9,444 11,334 29,987 199,334 292,947 E 24,354 23,914 16,498 43,001 99,721 207,488 5,999 10,712 7,992 10,920 0 35,623 E 508 0 0 836 0 1,344 0 0 807 0 0 807 E 0 0 2,420 0 0 2,420 0 1,614 13,541 0 0 15,155 W 0 2,443 12,569 14,807 4,498 34,317 14 938 22,042 8,252 143,933 175,179 SW 1,682 2,471 0 0 20,389 24,542 5,782 27,956 34,384 184,723 267,465 520,310 NW 6,981 12,474 27,895 148,259 259,824 455,433 W 5,473 6,215 31,331 191,767 365,578 600,364 W 4,860 8,809 17,850 115,424 78,820 225,763 tal 120,443 164,097 248,750 808,051 1,493,818 2,835,159 28/18 2.1-18 Rev. 31

2000 PROJECTED Distance to Plant Sector 0-10 10-20 20-30 30-40 40-50 Total 6,166 24,028 28,707 35,404 20,273 114,578 E 17,487 37,551 25,721 29,926 38,135 148,820 46,203 10,183 12,196 31,611 206,940 307,133 E 26,256 25,744 17,663 45,998 105,848 221,509 6,467 11,497 8,553 11,687 0 38,204 E 551 0 0 895 0 1,446 0 0 878 0 0 878 E 0 0 2,635 0 0 2,635 0 1,759 14,742 0 0 16,501 W 0 2,660 13,688 16,122 4,897 37,367 14 1,022 24,000 8,985 156,725 190,746 SW 1,810 2,641 0 0 22,201 26,652 6,228 29,887 36,343 195,006 281,709 549,173 NW 7,524 13,340 29,762 156,623 273,153 480,402 W 5,901 6,660 33,435 200,205 380,339 626,540 W 5,239 9,492 19,194 121,620 83,732 239,277 tal 129,846 176,464 267,517 854,082 1,573,952 3,001,861 28/18 2.1-19 Rev. 31

2010 PROJECTED Distance to Plant Sector 0-10 10-20 20-30 30-40 40-50 Total 6,352 24,773 30,056 36,785 21,101 119,067 E 18,031 38,716 26,730 31,421 39,720 154,618 47,626 10,499 12,626 32,221 210,368 313,340 E 27,072 26,652 18,530 48,258 109,494 230,006 6,669 11,986 8,981 12,272 0 39,908 E 593 0 0 940 0 1,533 0 0 920 0 0 920 E 0 0 2,761 0 0 2,761 0 1,847 15,445 0 0 17,292 W 0 2,788 14,344 16,896 5,132 39,160 15 1,073 25,151 9,416 164,248 199,903 SW 1,867 2,689 0 0 23,267 27,823 6,417 30,426 37,096 199,100 286,889 559,928 NW 7,757 13,590 30,311 159,776 278,156 489,590 W 6,081 6,807 34,052 202,762 384,902 634,604 W 5,403 9,778 19,778 123,964 85,735 244,658 tal 133,883 181,624 276,781 873,811 1,609,012 3,075,111 28/18 2.1-20 Rev. 31

2020 PROJECTED Distance to Plant Sector 0-10 10-20 20-30 30-40 40-50 Total 6,549 25,541 31,470 38,219 21,963 123,742 E 18,584 39,916 27,784 32,989 41,349 160,622 49,105 10,825 13,051 32,748 213,221 318,950 E 27,907 27,557 19,336 50,343 112,285 234,428 6,874 12,452 9,376 12,811 0 41,513 E 615 0 0 981 0 1,596 0 0 965 0 0 965 E 0 0 2,894 0 0 2,894 0 1,939 16,184 0 0 18,123 W 0 2,922 15,033 17,707 5,379 41,041 15 1,127 26,355 9,869 172,131 209,497 SW 1,922 2,737 0 0 24,383 29,042 6,611 30,974 37,863 203,283 292,190 570,921 NW 8,000 13,844 30,871 162,992 283,254 498,961 W 6,269 6,957 34,678 205,354 389,518 642,776 W 5,572 10,070 20,382 126,369 87,794 250,187 tal 138,023 186,861 286,242 893,665 1,643,467 3,148,258 28/18 2.1-21 Rev. 31

2030 PROJECTED Distance to Plant Sector 0-10 10-20 20-30 30-40 40-50 Total 6,746 26,332 32,953 39,716 22,860 128,607 E 19,156 41,155 28,879 34,637 43,058 166,885 50,620 11,159 13,494 33,286 216,112 324,671 E 28,772 28,495 20,176 52,519 115,158 245,120 7,087 12,937 9,789 13,375 0 43,188 E 642 0 0 1,024 0 1,666 0 0 1,011 0 0 1,011 E 0 0 3,033 0 0 3,033 0 2,036 16,957 0 0 18,993 W 0 3,062 15,755 18,558 5,637 43,012 15 1,183 27,619 10,342 180,394 219,553 SW 1,979 2,787 0 0 25,554 30,320 6,809 31,532 38,647 207,551 297,607 582,146 NW 8,247 14,102 31,441 166,276 288,449 508,515 W 6,459 7,110 35,317 207,981 394,192 651,059 W 5,745 10,373 21,003 128,835 89,919 255,875 tal 142,277 192,263 296,074 914,100 1,678,940 3,223,654 28/18 2.1-22 Rev. 31

Sector 0-1 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8-9 9-10 Tot N 0 310 0 0 0 0 0 74 0 413 797 NNE 0 0 0 374 897 2,073 174 0 0 444 3,962 NE 0 0 636 210 697 1,352 1,542 534 0 0 4,971 ENE 0 0 0 2,501 0 888 0 1,043 1,609 266 6,307 E 0 292 0 0 0 1,330 0 0 183 0 1,805 ESE 0 0 0 0 0 0 0 0 0 68 68 SE 0 0 0 0 0 0 0 0 0 0 0 SSE 0 0 0 0 0 0 0 0 0 0 0 S 0 0 0 0 0 0 0 0 0 0 0 SSW 0 0 0 0 0 0 0 0 0 0 0 SW 0 0 0 0 0 0 0 0 0 0 0 WSW 0 0 0 0 0 0 0 0 0 0 0 W 0 0 0 0 0 0 263 0 864 0 1,127 WNW 0 0 345 0 0 0 0 0 0 0 345 NW 0 0 0 843 0 0 0 0 0 0 843 NNW 0 0 0 298 1,250 0 0 0 0 0 1,548 TOTAL 0 602 981 4,226 2,844 5,643 1,979 1,651 2,656 1,191 21,77 Note: Includes student enrollment only.

Sources: Connecticut Department of Education listing of schools; Telephone survey conducted in March 1992.

06/28/18 2.1-23 Rev. 31

Sector 0-1 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8-9 9-10 Tot N 0 0 0 300 0 0 0 0 0 200 500 NNE 0 0 0 0 0 0 375 375 107 277 1,134 NE 0 0 375 80 831 0 375 375 0 0 2,036 ENE 0 0 0 0 8,800 5,500 820 0 0 0 15,12 E 0 0 0 0 0 0 0 0 0 0 0 ESE 0 0 0 0 0 0 0 0 0 0 0 SE 0 0 0 0 0 0 0 0 0 0 0 SSE 0 0 0 0 0 0 0 0 0 0 0 S 0 0 0 0 0 0 0 0 256 0 256 SSW 0 0 0 0 0 0 0 0 0 0 0 SW 0 0 0 0 0 0 0 0 0 0 0 WSW 0 0 0 0 0 0 0 0 0 0 0 W 0 0 0 0 0 0 0 0 0 0 0 WNW 0 0 0 0 0 0 125 125 0 0 250 NW 0 500 0 0 0 0 125 125 0 0 750 NNW 0 0 0 0 0 0 0 0 0 0 0 TOTAL 0 500 375 380 9,631 5,500 1,820 1,000 363 477 20,04 Note: Firms with 50 employees or more. Excludes plant employee population.

Sources: Telephone survey conducted in March 1992.

06/28/18 2.1-24 Rev. 31

STATE PARKS AND FORESTS (WITH DOCUMENTED ATTENDANCE)

TOTAL ANNUAL SUMMER DAILY CILITY LOCATION ATTENDANCE ATTENDANCE te Parks:

Bluff Point ENE/E 6-8 97,641 490

• Fort Griswold ENE 5-6 58,965 200

• Haley Farm ENE/E 7-9 11,675 60

• Harkness Memorial E 2-3 157,962 790

• Rocky Neck W 3-5 412,495 2,360 **

te Forests:

Nehantic WNW/NNW 7-10 81,146 400

• TES:

aily summer attendance based on 90% of yearly attendance from April through September.

ncludes campers from April 15 to September 15.

rce:

e of Connecticut DEP - Office of Parks and Forests, 1990 Park Attendance.

28/18 2.1-25 Rev. 31

DISTRIBUTIONS RECTION 1990 CENSUS 2030 PROJECTED 1,298 1,536 E 903 1,065 1,144 1,351 E 768 909 760 899 E 179 212 0 0 E 0 0 0 0 W 0 0 3 3 SW 429 506 1,025 1,211 NW 1,046 1,233 W 1,167 1,377 W 1,124 1,327 TAL LPZ 9,846 11,629 rces:

0 Census of Population and Housing.

necticut Office of Policy and Management, Interim Population Projections Series 91.1, 4/91.

28/18 2.1-26 Rev. 31

EMPLOYMENT DIRECTION SCHOOL EMPLOYMENT 310 0 E 0 0 0 75 E 0 0 292 0 E 0 0 0 0 E 0 0 0 0 W 0 0 0 0 SW 0 0 0 0 NW 345 0 W 0 500 W 0 0 TAL 947 575 TES:

1-1992 Student Enrollment.

ms with 50 employees or more.

rce:

phone survey conducted in March 1992; Connecticut Department of Education school listing.

28/18 2.1-27 Rev. 31

CENSUS POPULATION AREA 1990 POPULATION dgeport - Milford, CT PMSA 443,722 stol, CT PMSA 79,488 l River, MA-RI PMSA 157,272 rtford, CT PMSA 767,899 w Haven - Meriden, CT MSA 530,240 ssau - Suffolk, NY PMSA 2,609,212 w Britain, CT PMSA 148,188 w London - Norwich, CT-RI MSA 266,819 vidence, RI PMSA 654,869 terbury, CT MSA 221,629 ddletown, CT PMSA 90,320 TES:

SA - Primary Metropolitan Statistical Area.

A - Metropolitan Statistical Area.

al population of metropolitan areas completely or only partially within 50 miles of the site.

rce:

0 Census of Population 28/18 2.1-28 Rev. 31

STATE MUNICIPALITY 1990 POPULATION nnecticut Branford 27,603 Bristol 60,640 Cheshire 25,684 East Hartford 50,452 East Haven 26,144 Enfield 45,532 Glastonbury 27,901 Groton 45,144 Hamden 52,434 Hartford 139,739 Manchester 51,618 Meriden 59,479 Middletown 42,762 Milford 49,938 Naugatuck 30,625 New Britain 75,491 New Haven 130,474 New London 28,540 Newington 29,208 Norwich 37,371 Shelton 35,418 Southington 38,518 Stratford 49,389 Vernon 29,841 Wallingford 40,822 Waterbury 108,961 West Hartford 60,110 West Haven 54,021 Wethersfield 25,651 Windsor 27,817 28/18 2.1-29 Rev. 31

STATE MUNICIPALITY 1990 POPULATION ode Island Coventry 31,083 Cranston 76,060 Johnston 26,542 Newport 28,227 Warwick 85,427 West Warwick 29,268 w York Brookhaven 407,779 Southampton 44,976 TES:

nicipalities with 25,000 people or more.

nicipalities completely or only partially within 50 miles.

rce: 1990 U.S. Census of Population and Housing.

28/18 2.1-30 Rev. 31

Distance (km)

Average rection 0-2 2-4 4-6 6-8 8-10 10-20 0-20 194 575 345 25 83 161 166 E 15 522 504 106 405 169 212 566 557 194 2,970 1,759 234 525 E 1,214 218 786 1,990 1,255 334 482 1,538 386 403 1,903 482 305 383 E 0 279 0 0 0 142 147 0 0 0 0 0 0 0 E 0 0 0 0 0 0 0 0 0 0 0 0 0 0 W 0 0 0 0 0 126 126 0 305 686 0 0 0 520 SW 0 1,153 270 1,187 980 178 369 0 545 308 80 61 171 167 NW 0 727 324 17 20 60 83 W 0 550 217 78 63 64 82 W 492 969 286 154 71 107 126 erage 409 546 375 570 428 166 236 TES:

eople per square kilometer.

28/18 2.1-31 Rev. 31

Distance (km) rection 0-20 20-40 40-60 60-80 166 103 124 42 E 212 205 73 77 525 58 63 412 E 482 117 86 402 383 198 167 364 E 147 0 29 0 0 87 0 0 E 0 98 0 0 0 88 96 0 W 126 104 122 112 520 142 134 471 SW 369 194 0 907 167 151 302 781 NW 83 69 316 504 W 82 53 260 879 W 126 56 140 235 erage 236 104 163 416 28/18 2.1-32 Rev. 31

Sector 0-1 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8-9 9-10 Aver N 82 1,226 883 571 66 99 212 71 161 460 292 NNE 66 610 1,168 1,440 1,054 751 653 762 657 843 827 NE 842 772 855 2,830 5,993 3,591 3,200 2,761 273 526 2,183 ENE 112 772 298 3,612 550 3,328 1,469 1,035 302 714 1,241 E 0 1,080 421 1,313 109 256 0 21 430 242 306 ESE 0 243 37 0 0 0 0 0 34 57 26 SE 0 0 0 0 0 0 0 0 0 0 0 SSE 0 0 0 0 0 0 0 0 0 0 0 S 0 0 0 0 0 0 0 0 0 0 0 SSW 0 0 0 0 0 0 0 0 0 0 0 SW 0 0 14 0 0 0 0 0 0 0 1 WSW 0 0 498 66 49 145 185 54 0 20 86 W 0 302 1,082 738 249 353 186 191 264 109 295 WNW 0 808 1,188 1,429 196 111 83 562 153 112 356 NW 0 1,076 890 868 646 298 235 34 63 22 279 NNW 755 533 909 380 366 425 87 146 137 84 248 AVERAGE 116 464 515 828 580 585 394 352 155 199 384 Source: 1990 Census of Population.

06/28/18 2.1-33 Rev. 31

Sector 0-1 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8-9 9-10 Aver N 97 1,452 1,041 675 77 116 250 82 189 544 344 NNE 71 722 1,377 1,700 1,243 887 771 900 776 995 976 NE 985 908 1,009 3,345 7,084 4,243 3,780 3,263 322 621 2,579 ENE 133 915 350 4,272 648 3,933 1,736 1,222 356 844 1,466 E 0 1,275 496 1,553 130 303 0 25 507 286 361 ESE 0 284 44 0 0 0 0 0 45 75 33 SE 0 0 0 0 0 0 0 0 0 0 0 SSE 0 0 0 0 0 0 0 0 0 0 0 S 0 0 0 0 0 0 0 0 0 0 0 SSW 0 0 0 0 0 0 0 0 0 0 0 SW 0 0 15 0 0 0 0 0 0 0 1 WSW 0 0 591 79 57 170 219 63 0 22 101 W 0 360 1,278 872 294 417 220 225 313 123 347 WNW 0 951 1,404 1,692 232 130 98 664 180 131 420 NW 0 1,270 1,049 1,025 764 352 278 39 74 25 329 NNW 888 630 1,075 450 431 503 102 172 162 100 293 AVERAGE 136 548 608 979 685 691 466 416 183 235 453 Source: CT Office of Policy and Management, Interim Population Projections Series 91.1, 4/91.

06/28/18 2.1-34 Rev. 31

Sector 0-10 10-20 20-30 30-40 40-50 Average N 292 378 269 237 106 215 NNE 827 591 242 200 202 281 NE 2,183 160 116 218 1,129 597 ENE 1,241 406 168 313 564 423 E 306 182 81 79 0 73 ESE 26 0 0 6 0 3 SE 0 0 8 0 0 2 SSE 0 0 25 0 0 5 S 0 27 138 0 0 31 SSW 0 41 128 108 25 70 SW 1 16 225 60 815 357 WSW 86 42 0 0 115 50 W 295 475 350 1,345 1,514 1,061 WNW 356 212 284 1,079 1,471 928 NW 279 106 319 1,396 2,070 1,224 NNW 248 150 182 840 446 460 AVERAGE 384 174 158 368 528 361 Source: 1990 Census of Population and Housing.

06/28/18 2.1-35 Rev. 31

Sector 0-10 10-20 20-30 30-40 40-50 Average N 344 447 336 289 129 262 NNE 976 699 294 252 244 340 NE 2,579 190 138 242 1,224 662 ENE 1,466 484 206 382 652 499 E 361 220 100 97 0 88 ESE 33 0 0 7 0 3 SE 0 0 10 0 0 2 SSE 0 0 31 0 0 6 S 0 35 173 0 0 39 SSW 0 52 161 135 32 88 SW 1 20 281 75 1,021 447 WSW 101 47 0 0 145 62 W 347 536 394 1,511 1,685 1,187 WNW 420 240 320 1,210 1,633 1,036 NW 329 121 360 1,514 2,232 1,327 NNW 293 176 214 938 509 522 AVERAGE 453 204 189 416 594 410 Source: CT Office of Policy and Management, Interim Population Projections, Series 91.1, 4/91.

06/28/18 2.1-36 Rev. 31

Distance (km)

Direction 0-20 20-40 40-60 60-80 166 119 122 87 E 212 207 132 108 525 171 111 242 E 482 204 138 216 383 242 215 216 E 147 147 61 61 0 86 86 86 E 0 98 98 98 0 86 88 88 W 126 105 116 116 520 144 136 370 SW 369 344 344 640 167 155 233 469 NW 83 73 208 338 W 82 60 172 482 W 126 73 110 165 erage 236 134 150 260 28/18 2.1-37 Rev. 31

MILE)

Sector 0-10 0-20 0-30 0-40 0-50 N 292 357 308 277 215 NNE 827 650 423 326 281 NE 2,183 666 360 298 597 ENE 1,241 615 367 343 423 E 306 213 140 113 73 ESE 26 6 3 4 3 SE 0 0 5 3 2 SSE 0 0 14 8 5 S 0 21 86 48 31 SSW 0 31 85 95 70 SW 1 12 130 100 357 W 295 430 386 805 1,061 WNW 356 248 268 623 928 NW 279 149 244 748 1,224 NNW 248 174 178 468 460 Average 384 226 189 267 361 06/28/18 2.1-38 Rev. 31

SQUARE MILE)

Sector 0-10 0-20 0-30 0-40 0-50 N 344 421 374 337 262 NNE 976 768 505 394 340 NE 2,579 787 426 346 662 ENE 1,466 730 438 414 499 E 361 255 169 138 88 ESE 33 8 4 5 3 SE 0 0 6 3 2 SSE 0 0 17 10 6 S 0 26 108 60 39 SSW 0 39 107 119 88 SW 1 15 163 125 447 WSW 101 61 27 15 62 W 347 488 436 906 1,187 WNW 420 285 305 701 1,036 NW 329 173 277 818 1,327 NNW 293 205 210 529 522 Average 453 266 223 307 410 06/28/18 2.1-39 Rev. 31

06/28/18 2.1-40 Rev. 31 06/28/18 2.1-41 Rev. 31 06/28/18 2.1-42 Rev. 31 06/28/18 2.1-43 Rev. 31 06/28/18 2.1-44 Rev. 31 06/28/18 2.1-45 Rev. 31 06/28/18 2.1-46 Rev. 31 06/28/18 2.1-47 Rev. 31 06/28/18 2.1-48 Rev. 31 06/28/18 2.1-49 Rev. 31 06/28/18 2.1-50 Rev. 31 06/28/18 2.1-51 Rev. 31 1 LOCATIONS AND ROUTES area around the Millstone site contains three major industrial facilities (Dow Chemical poration, Pfizer Corporation, and Electric Boat Division of General Dynamics Corporation);

transportation facilities (Groton/New London) Airport and the New London Transportation ter; and four military installations (U.S. Navy Submarine Base, U.S. Coast Guard Academy, p Rell, and Stone's Ranch Military Reservation).

re is also an interstate highway (Interstate 95), passenger and freight railroad lines, gas ribution lines, above ground gas and oil storage facilities and two major waterways (Long nd Sound, Thames River) in the vicinity of the Millstone site.

re are no major gas transmission lines, oil transmission or distribution lines, underground gas age facilities, drilling or mining operations, or military firing, or bombing ranges near the site.

locations of the major industrial, transportation and military facilities are shown on ure 2.2-1. Aircraft patterns and routes are shown on Figures 2.2-2 and 2.2-3. Figure 2.2-4 ws the road and highway system in the area of the Millstone site.

2 DESCRIPTIONS 2.1 Description of Facilities ummary of the significant industrial, transportation, military, and industrial related facilities is wn in Table 2.2-1, as listed below.

1. Dow Chemical Corporation of Allen Point, Ledyard, Connecticut is located on the east bank of the Thames River approximately 10 miles north-northeast of the site.

Dow Chemical is a producer of synthetic compounds and employs approximately 115 persons.

2. Pfizer Corporation of Eastern Point Road, Groton, Connecticut is located on the east bank of the Thames River, approximately 4.9 miles east-northeast of the site.

Pfizer Corporation is a producer of pharmaceutical and medical supplies, employing approximately 3,000 persons.

3. Electric Boat Division of General Dynamics of Eastern Point Road, Groton, Connecticut is located approximately 5 miles east-northeast of the site. Electric Boat employs approximately 12,000 persons, and is a producer of submarines and oceanographic equipment for commercial industry and the U.S. Navy.

4. Groton/New London Airport, approximately 6 miles east-northeast of the site, handles regularly scheduled commercial passenger flights (Section 2.2.2.5).

Approximately 13 persons are employed at Groton/New London Airport on a 28/18 2.2-1 Rev. 31

employees.

5. The New London Transportation Center, located at City Pier, New London on the west bank of the Thames River, is approximately 4 miles northeast of the site.

Approximately 20 persons are employed there on a full time basis.

6. U.S. Navy Submarine Base, Groton, Connecticut is located on the east bank of the Thames River, approximately 7 miles northeast of the site. The base population includes approximately 8,500 military personnel. In addition, there are about 1,800 civilian employees at the base.

7. The U.S. Coast Guard Academy, New London, Connecticut is located on the west bank of the Thames River, approximately 5.6 miles northeast of the site.

Approximately 900 cadets attend the academy, while approximately 360 military and civilian personnel are employed here.

8. The Connecticut National Guard facility, located approximately 2 miles northwest of the site, is a training headquarters for the Connecticut Army National Guard. It is owned and operated by the Military Department of the State of Connecticut. On a full-time basis, it employs 16 persons (military and civilian), including the headquarters for the Connecticut Military Academy, Post Operations personnel, and the 745th Signal Company. On a part-time basis, during various weekends, Camp Rowland is occupied by varying numbers of troop units for administrative training maneuvers, billeting, and supply functions for the Connecticut Army National Guard. During the training maneuvers there may be from 300 to 1,200 people at the facility.

9. In addition to the Connecticut National Guard facility, the Military Department of the State of Connecticut also maintains a field training facility known as Stone's Ranch Military Reservation, located approximately 7 miles northwest of the site.

Fourteen persons are employed here full-time for two regional motor vehicle and equipment maintenance shops. It is also occupied on a part-time basis by varying numbers of troop units for periods of field training for the Connecticut Army National Guard. During some weekend training sessions there may be up to 500 people at the facility.

10. Hess Oil Corporation of Eastern Point Road, Groton, Connecticut is located on the east bank of the Thames River, approximately 5 miles east-northeast of the site. It is located north of Pfizer Corporation, and south of General Dynamics-Electric Boat Division and services as a fuel storage facility. There are about 14 persons employed there on a full time basis.

28/18 2.2-2 Rev. 31

northeast of the site on Great Neck Road, and employs about 75 people.

On the Millstone site, at the Fire Training Facility located approximately 2,800 feet to the north of the protected area (3,400 feet to Unit 3 Control Room), are two 1,000 gallon propane cylinders. The two cylinders are used to supply propane to the fire simulator.

12. Montville Station is a Fossil Fuel powered electric generating plant operated by Connecticut Light & Power Company in Montville, Connecticut. It is located on the west bank of the Thames River, approximately 9.5 miles north-northeast of the site. Approximately 67 people are employed there.

2.2 Description of Products and Materials

1. Dow Chemical produces organic compounds, such as Styron, Styrofoam, and a base product of latex paints. All materials are moved to and from the company by truck and/or railroad.

2. Pfizer Corporation produces organic compounds and pharmaceutical materials, such as citric acid, antibiotics, synthetic medicines, vitamins and caffeine. All materials are moved to and from Pfizer Corporation by truck and/or railroad.

3. The nature of products produced at Electric Boat requires that they handle substantial amounts of nuclear material which is licensed under the Naval Reactors Division. All material is moved by truck, railroad, and/or barge to and from the company with the exception of completed ships which leave under their own power.

4. Groton/New London Airport (Section 2.2.2.5)

5. The New London Transportation Center is a large complex in downtown New London in the City Pier area. It encompasses numerous facilities, including a train station, several ferry companies, commercial and private boat slips, an interstate bus terminal, local bus interchangers, and commercial land transportation facilities. It serves as the prime entrance and exit for New London for civilian and commercial travel.

6. The U.S. Navy Submarine Base provides logistics as well as training and operation of the base and its ships (nuclear and non-nuclear). All materials are moved by truck, railroad, barge and/or ship to and from this government installation.

7. The U.S. Coast Guard Academy is headquarters for indoctrination and training of future officers in the Coast Guard. All materials used at the academy are of the software nature and are moved by truck.

28/18 2.2-3 Rev. 31

administrative nature of its occupancy, the camp's operation has no effect on the Station's operation.

9. Stone's Ranch Military Reservation is a military field training facility for the Connecticut Army National Guard. Limited quantities of munitions and explosives are stored in underground bunkers at this facility. These materials are used in quarry operations for the Connecticut Army Corps of Engineers. No live ammunition is used at the facility. All materials are moved to and from Stone's Ranch by truck.

In addition, a small paved utility landing strip is located at Stone's Ranch. While capable of handling light, fixed-wing aircraft, the strip is not routinely used except for occasional rotary-wing operations. Because of its distance from the site, the limited quantity of materials stored and used, and the type of aircraft operations occurring at the facility, Stone's Ranch Military Reservation does not pose any hazard to the Millstone station.

No other military operations such as firing ranges, bombing ranges, ordnance depots, or missile sites exist near the Millstone site.

10. Hess Oil Corporation operates a fuel distribution and storage facility for home heating oil and kerosene. There are large above ground tanks capable of storing heating oil, residual fuel oil, and kerosene. The fuel arrives by ships or barges and is distributed by trucks.

11. Hendel Petroleum Company operates a fuel distribution facility for commercial and residential use. There are 5 above ground tanks (3-30,000 gallons and 2-16,000 gallons) which are capable of storing 126,000 gallons total of propane gas.

The facility also stores 40,000 gallons of gasoline, and 40,000 gallons of No. 2 fuel oil. The propane for the facility arrives by train and truck, and is distributed by truck.

The Fire Training Facility was constructed in 1994 for the purpose of training Millstone's fire brigade members. The Training Facility consists of six live burn mock-ups which replicate nuclear power plant fire hazards. Propane is used to fuel these fireplaces.

Two 1,000 gallon propane storage cylinders are located at the Training Facility.

These two cylinders are positioned such that their ends are pointed away from the Millstone site. Both cylinders are above ground domestic storage cylinders designed per ASME Code for Pressure Vessels,Section VIII Division 1-92.

12. The Montville Station Electric Generating Station is capable of providing 498 mW of electric power. Its generators are powered by fossil fuel. The fuel is stored in 28/18 2.2-4 Rev. 31

12,000 barrels of fuel each, and two small above ground tanks, capable of storing approximately 250 barrels of fuel each. The fuel arrives by barges or trucks.

2.3 Pipelines re are no major transmission lines within 5 miles of the site. There are two medium pressure distribution lines in the near proximity of the site. The nearest gas distribution line is roximately 2.9 miles from the site, located along Rope Ferry Road in Waterford. This 35 psi distribution line is a 6-inch plastic pipeline, buried approximately 3 feet deep. The control e for this line is located at the intersection of Clark Lane and Boston Post Road in Waterford.

second gas distribution line, in place and pressurized, ends at and serves the shopping center plex, near the intersection of I-95 and Parkway North, approximately 4 miles north of the site.

s 35 psi gas distribution line is an 8-inch plastic pipeline buried approximately 3 feet deep. The trol valve for this line is located at the complex where it intersects with Parkway North.

re are no oil transmission or distribution lines within 5 miles of the Millstone site.

2.4 Waterways ps that pass by the site in the shipping channels of Long Island Sound are of two types: general o freighters, usually partially unloaded, with drafts of 20 to 25 feet, and deep draft tankers h drafts of 35 to 38 feet. Both of these classes of ships must remain at least 2 miles offshore to vent running aground on Bartlett Reef.

oil barges pass to the shore side of Bartlett Reef, and since there are no tank farms in Niantic

, no oil barges pass within 2 miles of the site. The largest oil barges have a capacity of 60,000 els and draw 15 feet 6 inches of water.

ge traffic in the vicinity of the site has been diminishing over the past several years due to the rease in the amount of oil used by area facilities. Barge traffic is heaviest during the winter nths, and averages only 1 barge per day during these months. On the average of once a month, arge carrying 15,000 barrels of sulfuric acid is towed past the site outside of Bartlett Reef.

roximately 10 ships per day traverse the Reef in the vicinity, 6 miles of the site.

these reasons, it is concluded that shipping accidents would not adversely affect Millstone 3 ty related facilities.

2.5 Airports re is one airport within 6 miles of the site: The Groton/New London Airport.

ton/New London Airport, approximately 6 miles east- northeast of the site, handles regularly eduled commercial passenger flights. It is served by two airlines: Action Airlines, and U.S. Air ress. It has two runways: 5-23, 5,000 feet long; and 15-33, 4,000 feet long; which are both 28/18 2.2-5 Rev. 31

Figure 2.2-2, the landing patterns used do not direct traffic near the Millstone site.

largest commercial aircraft to use Groton/New London Airport on a regularly scheduled basis Beachcraft 1900's which carry approximately 19 passengers. The only jets using the airport on gular basis are two small chartered Cessna Citation which carry 10 passengers.

ing fiscal year 1980-1981, an average of 96,000 civilian takeoffs and landings occurred at ton/New London Airport. Comparatively, during Calendar Year 1995, about 78,700 civilian offs and landings occurred.

largest military aircraft to use Groton/New London Airport on an occasional basis is C-130's.

re are also two C-23's. Additionally, there are several military helicopters stationed at the ort.

1995 there were approximately 4,490 military flights, approximately half of which were tary helicopters. Millstone station is not in the flight path of these flights, and pilots are fed to avoid the site.

largest aircraft to ever use Groton/New London Airport is a Boeing 727. However, the use of and other large aircraft at Groton/New London is limited and very infrequent.

shown on Figure 2.2-3, the air lane nearest the site is V58 which is approximately 4 miles heast of the site. Other adjacent air lanes include V16, which is approximately 6 miles hwest of the site, and V308, which is approximately 8 miles east of the site. The nearest h-altitude jet route, J121-581, passes approximately 9 miles southeast of the site. A second jet e, J55, passes approximately 12 miles northwest of the site.

2.6 Highways area around the Millstone site is served by interstate, state, and local roads. These are shown Figure 2.2-4.

nearest major highway which would be used for frequent transportation of hazardous erials is U.S. Interstate 95, which is located 4 miles from the Millstone site.

er principal highways which pass near the site include U.S. Highway 1 which is located 3 es from the site, and State Highway 156, located 1.5 miles from the site.

se separation distances exceed the minimum distance criteria given in Regulatory Guide 1.91, ision 1 and provide assurance that any transportation accidents resulting in explosions or toxic releases of truck size shipments of hazardous materials would not have a significant adverse ct on the safe operation or shutdown capability of the unit. See Section 2.2.3 for a more iled evaluation of potential accidents.

28/18 2.2-6 Rev. 31

site is traversed from east to west by a Providence & Worcester (P&W)/Amtrak railroad t-of-way. The mainline tracks are about 1,795 feet from the Millstone 3 containment structure.

h P&W and Amtrak trains are currently diesel powered. However, Amtrak, the operator of the senger train service, plans to electrify its passenger trains, and has embarked on a project to struct overhead electric lines to power the trains. The project is currently scheduled for pletion in 1997. These new lines will be 23 feet above the rails and will not affect the site nor overhead transmission lines leading out of the site which traverse the railroad line above the ks. Additionally, Amtrak is considering raising the track bed as much as 3 feet at various nts along the railroad line, but does not plan to do this where it traverses the Millstone site.

thheld under 10 CFR 2.390 (d)(1) 2.8 Projections of Industrial Growth elines expansion of facilities is presently planned in the area for oil distribution within the theastern region of Connecticut. The gas distribution line along Rope Ferry Road ends at erford High School, approximately 2.9 miles from the Millstone site. The gas distribution line 95 and Parkway North ends at, and serves the shopping complex approximately 4 miles from Millstone site.

28/18 2.2-7 Rev. 31

previously mentioned, ship and barge traffic in the area of the Millstone site has decreased r the past several years. No new ship or barge traffic is anticipated at this time in the Niantic area on Long Island Sound near the location of the intake structures.

ports expansion of facilities at Groton/New London Airport is proposed although some rovements to the facility, such as expansion of the approach lights, and upgrading of the inal and runways is planned. Southeastern Connecticut Regional Planning Agency (SCRPA) mmends that a master plan be prepared for the airport before any major physical rovements are made. The agency has previously adopted the policy that Groton/New London port should remain a small feeder airport providing connection to larger airports and direct ice to a limited number of cities within a 500-mile radius.

hways ee major highway improvements were made for the area around the Millstone site. The section Route 85 between I-95 and Route I-395 (Formally Route 52) was widened in 1989 in nection with the new shopping mall built on Route 85, the widening of Cross Roads ween I-95 and Route 85 in 1990 for another new shopping mall on Cross Roads, and a new ge between Waterford and East Lyme was completed in 1991 to replace the Niantic River dge with a high rise bridge one mile long. This high-level draw bridge replaced the older lower ng bridge, creating a smoother flow of traffic along State Highway 156.

lroads 982 there was a transfer of the operating rights of freight service over coastal trackage from Rail to the Providence & Worcester (P&W) railroad. While this involved the trackage near site, there was no appreciable change in either the amount or the nature of freight traffic.

luation of potential accidents and identification of design basis events are discussed in tion 2.2.3.

3 EVALUATION OF POTENTIAL ACCIDENTS evaluation of potential accidents includes analysis of hazardous materials from both offsite ustrial, transportation, and military facilities within a 5-mile radius of the Millstone site, as l as from specified onsite sources. Section 2.2.1 defines industrial, transportation, and military lities that exist within 10 miles of the Millstone site. All major industrial plants are more than iles from Millstone. Likewise, due to the innocuous nature of operations at nearby military allations, as well as the location of the Groton/New London airport and the nature of traffic the flight routes into and out of the airport, no potential accidents from military installations rom aircraft have been postulated concerning the safe operation or shutdown capability of the t.

28/18 2.2-8 Rev. 31

ers with drafts of 35 to 38 feet (Section 2.2.2.4). Both of these classes of ships must remain at t 2 miles offshore to avoid running aground on Bartlett Reef. Approximately ten ships per day sverse the shipping channels in the vicinity of the site (Section 2.2.2.4).

ce there are no tank farms in Niantic Bay, oil barges do not pass to the shore side of Bartlett f or within 2 miles of the site. Barge traffic is heaviest in the winter, averaging only one ed oil barge daily, the largest having a capacity of 60,000 barrels and a draw of 15 feet-6 es of water (Section 2.2.2.4). On the average of once a month, a barge carrying 15,000 barrels ulfuric acid is towed past the site, outside of Bartlett Reef. Total round-trip traffic is less than hips per day.

tion 2.2.2.4 defines the nature of water use relative to commercial shipping and recreational ting. The only safety related structure subject to this evaluation is the circulating and service er pumphouse. Since there is no commercial water traffic in the area of the pumphouse, the y consideration that exists is the remote possibility of a runaway barge colliding with the phouse.

possible damage to the pumphouse by a drifting barge was investigated. The barge can roach the pumphouse only through the intake channel, which is perpendicular to the front of pumphouse. The relatively shallow bay bottom surrounding the intake channel prevents the ge from hitting the side of the pumphouse. Should a barge hit the pumphouse from the front, age would be limited to the front wall of the recirculation tempering water gallery, which ects seaward from the pumphouse. The service water pumps, which are the only safety related ipment housed in the pumphouse, are located approximately 50 feet from the front wall. The ration of these pumps would not be impaired and the water intake source would not be ked, as the water intake source lies between elevations (-) 28 feet 0 inch and (-) 8 feet 0 inch.

these reasons, it is concluded that shipping accidents would not adversely affect safety related lities.

possibility of facility impacts due to explosion or release of hazardous materials from ustrial facilities was considered for two facilities listed in Section 2.2.2. Hendel Oil Company Hess Oil Company were selected for evaluation based on proximity to the site and volume of erial stored. Several incident conditions were modeled for each facility using Automated ource for Chemical Hazard Incident Evaluation (ARCHIE) version 1.00 produced by FEMA/

DOT and USEPA. ARCHIE is a software planning tool which provides an integrated method assessment of vapor dispersion, fire and explosion impacts related to the discharge of ardous material into the terrestrial environment.

uts to the model include physical properties of the hazardous material such as molecular ght, boiling point, and vapor pressure for various temperatures. These were obtained from the mical Engineer's Handbook, Fifth Edition, 1973. The type and quantity of hazardous material hand at each facility was obtained from the facility managers. Conservative assumptions were e where applicable, the most notable of which was that all the tanks at a facility should be 28/18 2.2-9 Rev. 31

le tank at each facility, since a major fault in more than one storage tank in the absence of an losion was considered unlikely.

first event considered was the potential for toxic concentrations of propane to reach the site m a release of propane gas from a commercial facility, other than by explosion. A nearly antaneous release (1 minute duration) coupled with stability class F (most stable) and a low d velocity (4.5 mph) was chosen to minimize diffusion of the puff of propane. Hendel Oil mpany has a 30,000 gallon tank which is located 2.5 miles from the site. The plume is servatively assumed to be transported by the wind directly towards the Control Room tilation intakes. The maximum concentration reached at the intakes will be approximately 1 ppm 31 minutes after tank rupture. Using the same input parameters and methodology to ss infiltration to the pressurized control room as in FSAR Section 2.2.3.1.4, the concentration de the control room should reach a maximum value of 13.4 ppm 61 minutes after the tank ure. Both values are well below the toxic vapor limit of 20,000 ppm. The only scenario in ch concentration anywhere on the Millstone site reaches or exceeds the toxic vapor limit ld occur in the case of an instantaneous release of the contents of all 5 tanks (126,000 gallons) propane from Hendel Oil Company without explosion or fire. In this unlikely event, centrations at the control room intakes could reach 29,146 ppm 31 minutes after the start of release. Concentrations inside the Control Room would reach 58 ppm (well below the toxic or limit), 61 minutes after the release.

thheld under 10 CFR 2.390 (d)(1) 28/18 2.2-10 Rev. 31

to its further distance from the site (5 miles), and the lesser volatility of the kerosene, #2 fuel and residual fuel oil stored there, there is no impact on the Millstone plant from a fire or losion at the Hess Oil facility. For these reasons, it is concluded that explosion or release of ardous material from any of these facilities would not adversely affect the safe operation or tdown capabilities of the plant.

er land and water uses prevailing in the Millstone Point vicinity are such that the unit's intake cooling water is not jeopardized by ice blockage and/or damage (the ocean temperatures hibit significant icing), or release of corrosive chemicals or oil (only remote and distant hore releases are possible).

thheld under 10 CFR 2.390 (d)(1) 28/18 2.2-11 Rev. 31

thheld under 10 CFR 2.390 (d)(1) determination of design basis events therefore provides an analysis and discussion of:

1. missiles generated by offsite events near Unit 3;

2. unconfined vapor cloud explosion hazard;

3. hydrogen storage at the site; and

4. toxic chemicals stored at the site.

3.1.1 Missiles Generated by Events near the Millstone Site guidelines of NUREG-0800 state that the aggregate probability of exceeding plant design eria associated with all identified external man made hazards be less than 10-6. In particular total probability of penetrating site proximity missile strikes on safety- related structures uld be shown to be less than 10-7 per year or the design bases be modified to accommodate m.

relative importance of potential sources of missiles is derived from two primary factors: (1) nature of shipment loading, and (2) shipment frequency past the site. Several studies show that ment of flammable compressed gases are the most likely sources to produce transportation fragments in the event of an accident. Depending on the nature of hazardous material and the al accident scenario the tank fragments may travel sufficient distances and create a potential at of damage upon impact to a safety related structure at the site.

following algorithm is used to estimate the aggregate probability of a violent rupture or losion from a rail shipment of hazardous materials capable of producing large missiles able to h safety related structures at the site:

28/18 2.2-12 Rev. 31

Ti re:

Pr = Aggregate probability of missiles generating ruptures or explosions from rail accidents of significance to safety related structures (events/year)

R= Number of hazardous materials likely to produce violent ruptures or explosions with significant missiles generating capability (dimensionless)

E= Frequency of events which result in explosions or violent ruptures capable of producing significant missiles (events/shipment)

Si = Shipment frequency of i-th hazardous material past site (shipment/year)

Li = Track exposure length for the i-th material (miles)

Ti = Average shipment trip length for i-th material (miles) mber of Hazardous Materials, R hazardous materials considered likely to produce significant missiles in terms of size and ential range were selected from the Hazardous Materials Link Report (ConRail, 1980) between w Haven and New London, Connecticut, fr January 1978 through June 1979. These materials e also found to be prevalent in more recent accident/incident data contained in special DOT earch and Special Programs Administration computer outputs of March 26, 1981 (Research Special Programs Administration, U.S. Dept. of Transportation, March 1981), and April 15, 1 (Research and Special Programs Administration, U.S. Dept. of Transportation, April 1981) car rupture data from the Railroad Tank Car Safety Research and Test Project Report, 2-7 (Association of American Railroads and Railway Progress Institute, 1972), and eral other pertinent railroad accident reports by the National Transportation Safety Board tober 1971 through July 1980).

materials selected (Table 2.2-2) are flammable compressed gases since they are known to duce a characteristic tank rupture event. The rupture event may range from a single r-pressure followed with fire to a boiling liquid vapor explosion (BLEVE).

quency of Events, E incidence of significant missile generating events is relatively infrequent in the transport of ardous materials and the material specific data is unreliable to be useful for the present babilistic analysis. In addition, specific data supplied by ConRail for the period March 30, 6, through December 31, 1979, contained no incidents involving explosions. Instead, a 28/18 2.2-13 Rev. 31

5-1979. In terms of violent tank car ruptures or explosions per tank car mile, the predicted es were as follows:

PNL-3308 3.1 x 10-9 events/tank car mile DOT (75-79) 1.5 x 10-9 events/tank car mile Battelle report considers non-accident related tank ruptures as well as transportation dents and it is further stated that about 20 percent of ruptures occur in non-accident situations.

have used Battelle event frequency in the present analysis, even though we recognize it to be onstrably conservative. The present analysis also accounts for the contribution to the average from slightly higher incidence for propane and LPG shipments.

pment Frequency, Si pment frequencies are derived from applicable data in the ConRail link report for the period uary 1978 through June 1979 (ConRail, 1980). Tank cars per year and per train for the modities in question appear in Table 2.2-2.

re recent shipment frequency shipment data was obtained for the time period January 1992 ugh December 1992. Frequency of shipment of anhydrous ammonia has remained steady at 5 per year. Propane shipments have decreased to 35-40 cars per year. This evaluation was servatively based on the January 1978 through June 1979 shipment data.

ithheld under 10 CFR 2.390 (d)(1) rage Shipment Trip Length, Ti average shipment lengths for each hazardous material derived from one percent Waybill ple of U.S. Tank Car shipments, or Appendix E to the Final Phase O2 Report, Accident iew, AAR-RPI No. RA 02-2-18 (1982).

28/18 2.2-14 Rev. 31

results from the above analysis are summarized in Table 2.2-4. The aggregate probability of car violent ruptures or explosions which can produce significant missiles is conservatively mated to be 5.6 x 10-9 per year. This is considerably below the NUREG-0800, Section 3.5.1.5, gested limit (1 x 10-7) for conservatively estimated explosion probability.

ithheld under 10 CFR 2.390 (d)(1) have used NASA Report 3023 computer program entitled THRUST to calculate the eleration velocity and displacement distances of fragments propelled by a liquified pressed gas. The NASA analysis assumes that a large portion of the vessel containing a id/gas mixture, in equilibrium at greater than atmospheric pressure, separates from the rest of storage vessel. As the liquid under pressure converts to gas when exposed to atmospheric sure a thrust is produced causing the fragment to move away from the scene of accident.

types of tank car fragments are illustrated in Table 2.2-5. In type A, the tank is shown to ure in two equal halves. In type B, the tank car is assumed to split in 2:1 ratio and the smaller ment is assumed to move away from the accident scene. Type C and D ruptures are not sidered in this analysis because:

1. In type C, the man-way has no significant amount of liquid to provide it with thrust.

2. In type D, the leak is relatively too slow to create a violent change in vapor/liquid equilibrium within the tank.

ithheld under 10 CFR 2.390 (d)(1) 28/18 2.2-15 Rev. 31

Federal Railroad Administration retrofit standards J, S, and T, for pressurized tank car uire thermal insulation protection head puncture shields, self-couplers, and upgraded safety ef valve capacities. According to Folden (Personal Communication between S.N. Bajpai, EC, and Robert Folden, Federal Railroad Administration, 1982), these retrofits have been alled on existing tank cars. The new compressed gas tank cars also meet these provisions in pliance with Docket HM144 and modified in subsequent notices under Titles 173 and 174.

compliance with retrofit standards is expected to result in substantial reduction in severity of ent ruptures. The Federal Railroad Administration believes that compressed flammable gas car head punctures and fire induced violent ruptures are greatly reduced or eliminated in 90 ent of the cases as a result of the improvements.

ording to Folden, the S, J, and T retrofit requirements together with self-couplers have uced the violent ruptures considerably. The ruptures in ammonia tank cars are principally due aterial degradation. However, ruptures in ammonia tank are not violent. Folden described one dent involving ammonia in which the tank just opened up along the seam and the ammonia ped without any thrusting fragments.

present analysis is based on the data from past experience and does not include the safety rovements resulting from DOT required safety retrofits. This analysis also includes the tribution of non-accident ruptures because the Battelle (Giffen et al., 1980) propane risk ssment study has been used as the reference point for the calculation of the probability of strophic ruptures of other hazardous materials.

overall risk to the Millstone plant due to catastrophic ruptures resulting from transport of ardous materials is subject to additional reducing factors. These factors are included in REG-0800, Section 3.5.1.5, and according to the following model:

Pt = Pe x Pmr x Psc x Pp x N (2.2.3-2) re:

Pt = Total probability per year of a damaging missile strike Pe = Probability of an explosion or rupture potentially capable of missile generation Pmr = Probability of a missile reaching the plant (that is, distance to safety related structures)

Psc = Probability of a missile striking a critical area Pp = Probability of a missile energy exceeding the energy required to penetrate the safety related structures N = Number of missiles per explosion 28/18 2.2-16 Rev. 31

AR-RPI No. RA-01-2-7 (1972) shows that in approximately one-third of major ruptures, no ificant missiles are generated. Therefore, it is reasonable to incorporate a conditional bability (Pm) of missile generation to the model. Thus the conditional probability of missile eration Pm = 0.67.

thheld under 10 CFR 2.390 (d)(1) tank car fragments (e.g., elliptical head) have different punching-shear characteristics than a ing telephone pole moving at 200 mph. Tank car head missiles have been known to demolish k walls, but tend to bounce off built stonewalls with little damage to the structure (Personal mmunication between S.N. Bajpai and Robert Folden 1982).

28/18 2.2-17 Rev. 31

thheld under 10 CFR 2.390 (d)(1) 28/18 2.2-18 Rev. 31

thheld under 10 CFR 2.390 (d)(1) 3.1.3 mpressed liquified gases are shipped over the railroad line adjacent to the Millstone site. These es normally are propane and anhydrous ammonia. In the event of a catastrophic rupture, the ified gas is released to the atmosphere under pressure, and a fraction of the liquid is vaporized.

remaining liquid, due to the cooling effect, remains as chilled liquid and vaporizes further n contact with the ground. The rapid loss of lading results in the formation of an unconfined or cloud which is at least partially mixed with air.

probability of a vapor cloud explosion on the railroad line adjacent to the Millstone site is ed on the probability of a catastrophic rupture event, the probability of flammable vapor cloud mation, the probability of wind direction from the railroad sector (bounded by the 1 psi r-pressure radius), and the probability of the vapor cloud encountering an ignition source.

probability of a flammable vapor cloud explosion is thus:

R (2.2.3-3)

P ve = Pri X Prfi X fw X Pii i=1 28/18 2.2-19 Rev. 31

Pve = Probability per year of vapor cloud explosion R = Number of hazardous materials likely to produce vapor cloud Pri = Probability of catastrophic rupture events per year for the i-th hazardous material Pvfi = Probability of forming a flammable vapor cloud fw = Frequency of wind speed which promotes transport and mixing with air Pii = Probability of finding an ignition source given that a flammable vapor cloud is formed by the i-th hazardous material mber of Hazardous Materials, R hazardous materials likely to produce an unconfined vapor cloud explosion due to a strophic rupture event on the railroad line adjacent to the Millstone Site are propane and ydrous ammonia.

bability of Catastrophic Rupture Events, Pri probability of catastrophic rupture events per year involving the i-th hazardous material is mated using the model described in Section 2.2.3.1.1 of this report. These probabilities are ented in Table 2.2-4.

bability of Forming a Flammable Vapor Cloud, Prfi catastrophic rupture events involving flammable compressed gases do not necessarily result in formation of vapor clouds. The usual case is that ignition source is available in the immediate nity of accident and a fire usually results. Depending on the actual accident scenario, the fire, worst, would cause the tank car contents to be released and result in the formation of a eball. The fireball accident scenario has no incident pressures associated with it to be of cern for the plant structures. However, the formation of a flammable vapor cloud and its sequent ignition is of potential safety concern. The formation of a flammable vapor cloud also lies that an ignition source was not available in the immediate vicinity of the scene of dent.

idental spill data (U.S. Dept. of Transportation, March 1981) was used to estimate the bability of forming a vapor cloud given a catastrophic rupture event. This probability was servatively estimated as 0.1.

d Speed Frequency, fW orable wind speed would allow optimum transport and mixing of air with the vapor cloud. The bability of favorable wind speed is assumed to be 1.0.

28/18 2.2-20 Rev. 31

catastrophic rupture event involving flammable compressed gases, an immediate encounter h an ignition source would typically result in a torching effect. In this case, the released gas is sumed immediately and the flames are confined locally. The torching effect can lead to an rged fire or, at worst, the formation of a fireball. The probability of encountering ignition is in the immediate vicinity of the accident and decreases away from it. The probability of tion for the torching effect, fire, and fireball formation is therefore, nearly 1.0.

formation of a flammable vapor cloud in or around the scene of an accident implies that an ediate ignition source was not encountered. The probability of an unconfined vapor cloud ountering an ignition source then decreases from nearly one to some value less than 1.0, which ependent upon the area of the vapor cloud.

probability of ignition was estimated using Table 9-2 of the Battelle PNL 3308 Report fen et al., 1980). The use of this table requires an estimation of the area of the vapor cloud for nservatively estimated instantaneous release of the compressed liquid.

area of the unconfined vapor cloud was estimated by calculating: (1) the weight, i.e., vapor ume, of the liquid which vaporizes upon exit from a tank car and, (2) the depth of the onfined vapor cloud above the ground.

weight fraction, which vaporizes upon exit from a tank car, is given by:

Cv f = 1 - exp ------ ( T b - T i ) (2.2.3-4) re:

Cv = Liquid heat capacity

= Heat of vaporization Tb = Normal boiling point Ti = Initial temperature of the stored liquid f = Fraction of the liquid that flash vaporizes.

fraction vaporized, for both the hazardous materials, was under 0.4. To be on the conservative

, the fraction vaporized was taken to be 0.5. Thus, knowing the weight of tank car lading ch was vaporized, the volume of the vapor cloud was estimated. The fraction of air entrained he vapor cloud was ignored for this purpose.

thickness of the vapor cloud above ground level was estimated by the following relation n by Kaiser and Griffiths (1982):

28/18 2.2-21 Rev. 31

a u2 re:

L=2 h = Thickness of the vapor cloud

= Density differences between cloud vapor and ambient air a = Density of air u* = The vapor cloud spreading velocity spreading velocity was assumed to be equal to the wind velocity.

estimated ignition probabilities are presented in Table 2.2-7.

Probability of an Unconfined Vapor Cloud Explosion probability of an unconfined vapor cloud explosion at Millstone 3 was calculated using the del discussed above. These probabilities are presented in Table 2.2-8.

aggregate estimated probability of an unconfined vapor cloud explosion is 2.54 x 10-11, ch is several orders of magnitude lower than the recommended range in Regulatory Guide

. The unconfined vapor cloud and associated explosion pressure, therefore, does not stitute a design basis event for the Millstone 3 plant.

3.1.4 Hydrogen Storage at the Site tion 2.2.3.1 describes the generator hydrogen storage facility. Each high pressure storage tube estrained from movement by its supporting frame and is provided with an approved shutoff e, bursting disc assembly, and vent. The installation is posted with NO SMOKING signs ted no further than a distance of 25 feet away. A fire wall is constructed between the hydrogen age facility and the east-west access road. Unauthorized entry is prevented by chain link ing and a locked gate. Since the generator hydrogen facility poses no hazard to safety related ctures, systems, or components, no further consideration is therefore required.

3.1.5 Toxic Chemicals assessment of control room habitability following a postulated accidental release of ardous chemicals includes both onsite and offsite sources. The analysis is based on Regulatory de 1.78, Assumptions for Evaluating the Habitability of a Nuclear Plant Control Room ing a Postulated Hazardous Chemical Release. The release of any hazardous chemical stored 28/18 2.2-22 Rev. 31

uently passing within 5 miles of the control room are also evaluated. Frequent shipments are ned as exceeding 10 per year for truck shipments, 30 per year for rail shipments, and 50 per r for barge shipments.

the Millstone 3 site, two potential accidents involving two toxic chemicals were analyzed r to Licensing Application. Chlorine was stored onsite in two separate 55 ton railroad tank

. In addition, liquid propane had been transported prior to 1982 by ConRail within 5 miles of site at a frequency greater than 30 railroad carloads per year. The chlorine tanks were removed eptember 1986.

effect of an accidental release of each of the chemicals on control room habitability was luated by calculating vapor concentrations as a function of time both outside and inside the trol room. This calculation was performed using methodology outlined in NUREG-0570, ic Vapor Concentrations in the Control Room Following a Postulated Accidental Release, and zing the assumptions described in Regulatory Guide 1.78. A brief description of the erlying assumptions follows.

postulated accident, the entire contents of the largest single storage container are released, lting in a toxic vapor cloud and/or plume which is conservatively assumed to be transported he wind directly toward the control room intakes. The formation of the toxic cloud or plume is endent upon the chemical nature of the release and ambient environmental characteristics. The re amount of the chemical stored as a gas is treated as a puff or a cloud which has a finite ume determined from the quantity and density of the stored chemical. A toxic substance stored liquid with a boiling point below the ambient temperature forms an instantaneous puff, due to hing (rapid gas formation) of some fraction of the quantity stored. The remaining liquid forms uddle which quickly spreads into a thin layer on the ground, subsequently vaporizing and ming a ground-level vapor plume. A liquid that has a boiling point above the ambient perature forms a puddle which evaporates by forced convection, resulting in a ground-level me with no flashing involved. In all cases, the puff and/or ground-level plume is dispersed by ospheric turbulence as it is transported by the wind directly toward the control room intakes.

effects of this postulated accident scenario are described in Section 2.2.3.2.

habitability of the control room is evaluated by comparing the calculated chemical centrations inside the control room with known human toxicity limits. These limits are rmined to be the lowest concentration of a chemical that could interfere with an operator's ity to function properly and are obtained from Regulatory Guide 1.78 and other appropriate rences. The control room is considered to be uninhabitable when toxic limits are exceeded by mates of control room concentration. The input data required for the analysis include the mical's physical properties, control room parameters, atmospheric stability, wind speed, ance from the spill to the control room air intakes, quantity of chemical released, and toxicity ts. For low boiling point liquids (i.e., chlorine and propane), the boiling point, puff density, t of vaporization, specific heat, and liquid density are required as input.

28/18 2.2-23 Rev. 31

perature of 30°C (80°F), were utilized to obtain the condition which would result in a imum control room concentration.

control room parameters that were used as input to the propane analysis consisted of the owing:

Air intake height above ground: 65 feet Control room volume: 191,940 ft3 Normal ventilation flow rate: 1450 cfm control room volume used in this analysis is conservative relative to the actual value ented in Table 15.6-12.

escription of the operation of the control room pressurization system is presented in FSAR tion 9.4.0. For propane chemical sources, the contents of the largest single storage container e used as the amount of chemical released during a postulated accident.

3.2 Effects of Design Basis Events accidents involving transportation of propane and anhydrous ammonia have the potential of ming flammable vapor clouds as well as rail tank car missiles. However, the probability of e events near the Millstone 3 site is lower than the 1.0 x 10-7 per year for consideration of h events as recommended by NUREG-0800 (USNRC 1981a), Section 2.2.3. The sportation accidents on the ConRail rail line near the Millstone 3 site do not form a design s event. Therefore, probable effects of these accidents are not discussed. The results of the c chemical analysis are presented in Figure 2.2-5 for propane.

thheld under 10 CFR 2.390 (d)(1) 28/18 2.2-24 Rev. 31

1 AAR-RPI No. RA-01-2-7, 1972. Association of American Railroads and Railway Progress Institute Final Phase 01 Report on Summary of Ruptured Tank Cars Involved in Past Accidents, Revised July 1972. Chicago, Ill.

2 AAR-RPI No. RA-02-2-18, 1972. Association of American Railroads and Railway Progress Institute Final Phase 02 Report on Accident Review, Chicago III.

3 Chemical Rubber Company, 1972. Handbook of Chemistry and Physics 44th and 53rd Editions.

4 ConRail 1980. Hazardous Materials Link Report between New Haven and New London, Connecticut from January 1978 through June 1979.

5 Giffen, C.A. et al., 1980. An Assessment of the Risk of Transporting Propane by Truck and Train. Report prepared for the U.S. Department of Energy by Pacific Northwest Laboratory, Battelle Memorial Institute.

6 Iotti, R.C.; Krotuik W.J.; and DeBoisblanc, D.R. 1973. Report of Topical Meeting on Water Reactor Safety. USAEC Washington, D.C. Hazards to Nuclear Plants from a Near Site Gaseous Explosions. Paper, March 26-28, 1973.

7 Kaiser, G.D. and Griffiths, R.F. 1982. The Accidental Release of Anhydrous Ammonia:

A Systematic Study of the Factors Influencing Cloud Density and Dispersion, Journal of the Air Pollution Control Association, Vol. 32, No. 1.

8 NASA Report 3023, 1978. Workbook for Estimating the Effects of Accidental Explosions in Propellant Ground Handling and Transport Systems.

9 NTSB-RAR-72-6, 1971. National Transportation Safety Board Railroad Accident Report for Houston, Tex.

10 NTSB-RAR-1, 1972. National Transportation Safety Board Accident Report for East St.

Louis, Mo.

11 NTSB-RAR-75-7, 1974. National Transportation Safety Board Railroad Accident Report for Houston, Tex.

12 NTSB-RAR-79-11, 1979. National Transportation Safety Board Railroad Accident Report for Crestview, Fla.

13 NTSB-RAR-81-1, 1980. National Transportation Safety Board Railroad Accident Report for Muldraugh, Ky.

28/18 2.2-25 Rev. 31

15 Perry & Chilton 1973. Chemical Engineers Handbook, 5th Edition McGraw-Hill, Inc.

16 Personal Communication between S.N. Bajpai and Robert Folden, Federal Railroad Administration, Office of Safety, February 17, 1982.

17 Regulatory Guide 1.78, 1974. Assumptions for Evaluating the Habitability of a Nuclear Plant Control Room during a Postulated Hazardous Chemical Release.

18 Research and Special Programs Administration, U.S. Department of Transportation, Washington, D.C. 1981. Computer Printout of Incidents Involving Deaths, Injuries, Damages Greater than $50,000 or Evacuations. Run Dated March 26, 1981, Covering Period December 22, 1970 to September 5, 1980.

19 Research and Special Programs Administration, U.S. Department of Transportation, Washington, D.C. 1981. Computer Printout of Incidents Involving Fire and Explosions by ConRail. Run dated 4/15/81 Covering Period June 6, 1973 through November 1, 1980.

20 Rhoads, R.E. et al., 1978. An Assessment of Risk of Transporting Gasoline by Truck PNL-2133. Pacific Northwest Laboratory (Battelle Memorial Institute), Richland, Washington.

21 Siewert, R.D. 1972. Evacuation Areas for Transportation Accidents Involving Propellant Tank Pressure Bursts. NASA Technical Memorandum X68277.

22 Tilton, B.E. and Bruce, K.M. 1980. Review of Criteria for Vapor Phase Hydro Carbons, Environmental Criteria and Assessment Office. U.S. EPA-600/8-80 p 6-150.

23 U.S. Department of Transportation. Incidents Involving LPG and Ammonia, Computer Runs Prepared for Stone & Webster, 1981.

28/18 2.2-26 Rev. 31

Approx. No. Persons Approximate Distance Facility Location Employed or Stationed From Site Miles Sector Industrial

1.

• Dow Chemical Corp. Ledyard 115 10+ NNE

2. ** Pfizer Corporation Groton 3,000 4.9 ENE 3.** Electric Boat (Division of General Dynamics Groton 12,000 5 ENE Transportation

4. ** Groton/New London Airport (Trumbull) Groton 153 6 ENE

5. ** New London Transportation Center New London 20 4 NE Military

6. ** U.S. Navy Submarine Base Groton 10,300 7 NE

7. ** U.S. Coast Guard Academy New London 1,260 5.6 NE

8. ** Connecticut National Guard facility East Lyme 16 2 NW

9. ** Stone's Ranch Military Reservation East Lyme 14 7 NW Industrial Related Facilities

10. ** Hess Oil Corporation Groton 14 5 ENE

11. ** Hendel Petroleum Co. Waterford 75 2.5 NE

12.

• Montville Station Electric Generation Plant Montville 67 10 NNE NOTES:

• Not shown; located approximately near 10 mile radius, NNE of site.

• • Location of facility on Figure 2.2-1.

06/28/18 2.2-27 Rev. 31

PRODUCING SIGNIFICANT MISSILES 28/18 2.2-28 Rev. 31

28/18 2.2-29 Rev. 31 RUPTURE CAPABLE OF MISSILE GENERATION 28/18 2.2-30 Rev. 31

TABLE 2.2-5 TYPES OF TANK CAR MISSILES Tank Splits at Mid-Seam.

Tank Splits in 2:1 Ratio with the Smaller Section Thrusting.

Manway Separates Tank Punctured at Head.

28/18 2.2-31 Rev. 31

ANGLE Postulated Missile Type (Table A)

Hazardous Material Type A Type B Type C Type D Propane 142 370 - -

Anhydrous ammonia 264 803 - -

28/18 2.2-32 Rev. 31

28/18 2.2-33 Rev. 31 28/18 2.2-34 Rev. 31 06/28/18 2.2-35 Rev. 31 06/28/18 2.2-36 Rev. 31 28/18 2.2-37 Rev. 31 06/28/18 2.2-38 Rev. 31 CONTROL ROOM 28/18 2.2-39 Rev. 31

s section provides a meteorological description of the site and its surrounding areas.

porting data are included in accompanying tables. Tables 2.3-1 through 2.3-18, 2.3-20 ugh 2.3-30 and 2.3-33 provide information about the site climatology and meteorology. They the historical record for the site and are not updates on a continual basis. Table 2.3-19 also vides meteorological information but the information continues to be of interest and use to ion personnel. As such, it will be updated to reflect major changes which affect plant safety or needed. Tables 2.3-31 and 2.3-32 provide information regarding the ongoing site eorological monitoring program and will be updated as necessary. Tables 2.3-34 through 77 provide information regarding atmospheric diffusion estimates. They also provide orical record for the site and are not updated on a continual basis.

1 REGIONAL CLIMATOLOGY climatology of the Millstone site region may be reasonably described by data collected by the ional Weather Service at Bridgeport, Connecticut. The National Weather Service Station for dgeport is located at the Sikorsky Memorial (Bridgeport Municipal) Airport, approximately 50 es west-southwest of the site. The airport is located on a peninsula which protrudes into Long nd Sound in a similar manner to the Millstone site peninsula.

Bridgeport meteorological data are reasonably representative of the climate at the Millstone since both Bridgeport and the site are influenced by similar synoptic scale and mesoscale eorological conditions. Temperature data prior to January 1, 1948, and precipitation and wfall data prior to March 1, 1948, are from cooperative observers in the Bridgeport area.

owing these dates, all data were collected at Bridgeport Municipal Airport locations. From y 16, 1953, to February 29, 1960, and June 1, 1981, to June 30, 1982, the Bridgeport weather ion was closed between the hours of 11 p.m. and 6 a.m. During these time periods, hourly data e recorded 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> per day by the National Weather Service (NOAA 1971, 1990).

1.1 General Climate general climate of the region is described with respect to types of air masses, synoptic ures, general airflow patterns, temperature, humidity, precipitation, and relationships between optic-scale atmospheric processes and local meteorological conditions.

1.1.1 Air Masses and Synoptic Features Millstone site region has a continental climate, modified by the maritime influence of Long nd Sound and the Atlantic Ocean, immediately to the south and southeast. The general ward movement of air encircling the globe at middle latitudes transports large air masses into region. Four types of air masses usually produce the meteorology in the region of the lstone site: cold, dry continental polar air originating in Canada; warm, moist tropical air inating over the Gulf of Mexico and the Atlantic Ocean; cool, damp maritime air originating r the North Atlantic; and modified maritime air originating over the Pacific Ocean. Constant raction of these air masses produces a large number of migratory cyclones and accompanying 28/18 2.3-1 Rev. 31

ropical origin affects the Millstone site region.

1.1.2 Temperature, Humidity, and Precipitation mean annual temperature is approximately 51°F at Bridgeport, Connecticut. Due to the ximity of Long Island Sound and the Atlantic Ocean, both the heat of summer and the cold of ter are moderated. During the summer months, normal monthly temperatures near the reline average 3°F to 5°F cooler than nearby inland stations. Temperatures of 90°F or greater ur an average of seven days per year at Bridgeport, while temperatures of 100°F or greater e occurred only in July and August; with an extreme maximum of 103°F occurring in July

7. Freezing temperatures have not been recorded during the summer months (NOAA 1990).

ters are moderately cold, but seldom severe. Minimum daily temperatures during the winter nths are usually below freezing, but subzero (°F) readings are observed, on the average, less one day every two years. Below zero temperatures have been observed in each winter month, h an extreme minimum of -20°F occurring in February 1934 (NOAA 1971, 1990).

le 2.3-1 presents monthly, seasonal, and annual averages and extremes of temperature at dgeport (NOAA 1970, 1975, 1975, 1978, 1981; Weather Bureau 1959; Weather Bureau 1960),

le Table 2.3-2 gives the mean number of days with selected temperature conditions (NOAA 0, 1974, 1975, 1978, 1981).

normal annual precipitation at Bridgeport is well distributed throughout the year. Migratory

-pressure systems, and their accompanying frontal zones, produce most of the precipitation ughout the year. From late spring through early fall, bands of thunderstorms and convective wers produce considerable rainfall. These storms, often of short duration, frequently yield the viest short-term precipitation amounts. During the remainder of the year, the heaviest amounts ain and snow are produced by storms moving up the Atlantic coast of the eastern United es. Precipitation of 0.01 inch or more occurs approximately 117 days annually (NOAA 1990).

the average, relative humidity values are lowest during the winter and spring months in the y afternoon. Relative humidity values are at a maximum during the summer and fall months in early morning hours. On occasions, the humidity is uncomfortably high for periods up to eral days during the warmer months. Table 2.3-3 (NOAA 1970, 1974, 1975, 1978, 1981; AA 1949-1980) gives the monthly, seasonal, and annual averages and extremes of relative idity.

1.1.3 Prevailing Winds weather pattern in the region is controlled by the global band of prevailing westerly winds ughout most of the year. These winds act as the steering currents for synoptic scale weather ems which produce day-to-day weather changes.

28/18 2.3-2 Rev. 31

n humid southwesterly winds occur most frequently. Winds from the south through the t-southwest sectors occur nearly 42 percent of the time during the summer months, displaying increased activity of a sea breeze during these months. Table 2.3-4 presents monthly, onal, and annual frequency distributions of wind direction at Bridgeport, while Table 2.3-5 AA 1949-1980) shows directional persistence. Winds were assumed to persist if they ained in the same 22.5-degree sector for at least 5 consecutive hours.

annual frequency of calm winds (less than 2 mph) is 2.9 percent. The highest frequency of m and light winds (less than or equal to 3 mph) occurs during the summer season. Higher wind eds commonly occur from November through April when weather systems of synoptic scale strongest. Wind speeds greater than 25 mph occur 6.2 percent of the time during the months of ember through February. Table 2.3-6 (NOAA 1949-1980) gives the frequency distributions ind speed at Bridgeport.

1.1.4 Relationships of Synoptic to Local Conditions inland terrain in Connecticut is not pronounced enough to produce any significant local difications of synoptic conditions at the shoreline. The shoreline areas do, however, experience l modifications of synoptic patterns because of the temperature differences between air over and air over water. The most pronounced modification is the development of a diurnal sea ze, commonly experienced in the months of April through October on sunny days. During the time on these days, solar heating of land causes relative low pressure over land near ground l and relative high pressure over water offshore. This results in the setup of a mesoscale wind ulation near the shoreline from water to land, with a return flow aloft. This sea breeze is etimes strong enough to set up in the face of an offshore pressure gradient (i.e., northerly ds) but it most commonly occurs as a reinforcement of the typical summertime southwesterly d flow associated with an offshore high pressure system.

1.2 Regional Meteorological Conditions for Design and Operating Bases sonal and annual frequencies of severe weather phenomena are provided in this subsection.

1.2.1 Strong Winds ng winds, usually caused by intense low pressure systems, tropical cyclones, or passages of ng winter frontal zones, occasionally affect the region. For the period from 1961 through 0, the fastest mile wind speed recorded at Bridgeport was 74 mph occurring with a south wind eptember 1985. Table 2.3-7 lists extreme wind speeds on a monthly, seasonal, and annual s (NOAA 1990).

test-mile wind speeds of 50, 60, 70, 75, and 90 mph are expected to recur at the site in rvals of approximately 2, 10, 25, 50, and 100 years, respectively, according to a study by m (1968). Based on observations from Montauk Point (located about 23 miles southeast of lstone Point on the eastern tip of Long Island), the maximum reported wind speed in the 28/18 2.3-3 Rev. 31

1.2.2 Thunderstorms and Lightning nderstorms most commonly occur during the late spring and summer months, although they e been observed during all months of the year. Severe thunderstorms with strong winds, heavy

, intense lightning, and hail have infrequently affected the region. Table 2.3-8 presents the nthly, seasonal, and annual frequency of thunderstorm days at Bridgeport (NOAA 1990).

tudy of storm data indicates that intense lightning often accompanies strong thunderstorms in region. Lightning strikes have injured or killed people and animals, caused numerous power ures, and have damaged or destroyed dwellings by setting them afire (NOAA 1959-1981).

frequency of lightning strikes during a thunderstorm is dependent upon the storm's intensity development. A nomograph of the number of lightning strikes per year (normalized for a on with 30 thunderstorm days per year) as a function of isolated object height, indicates about rikes per year for a 450-foot object located on level terrain (Viemeister 1961).

quantity of charge flowing out of a single stroke is typically 20 coulombs with a range from o 50 coulombs (Tverskoi 1965). The current strength may reach 1.0 to 1.5x105 amperes; but 80 percent of the measured cases, it does not exceed 2.0x104 amperes (Tverskoi 1965). A onable estimate of 2.0 to 2.5x104 amperes (Tverskoi 1965; Neuberger 1965) is common for a y developed thunderstorm.

1.2.3 Hurricanes ms of tropical origin occasionally affect the region during the summer and fall months.

ording to a statistical study by Simpson and Lawrence (1971), the 50-mile segment of stline on which Millstone is located, was crossed by five hurricanes during the 1886 through 0 period.

1.2.4 Tornadoes and Waterspouts m a study of tornado occurrences during the period of 1955 through 1967 (augmented by 8-1981 storm data reports), the mean tornado frequency in the one-degree (latitude-longitude) are where the Millstone site is located is determined to be approximately 0.704 per year AA 1959-1981; Pautz 1969). Applying Thom's method for determining the probability of a ado striking a point on the Millstone site, it is conservatively estimated to be 0.00055 per year h a recurrence expected every 1,804 years (Thom 1963). Section 2.3.2.3.1 discusses the design s tornado.

erspouts have been observed over the waters of Long Island Sound (NOAA 1959-1981). Six erspouts were observed off shore of Connecticut from 1955 through 1967 (Pautz 1969).

28/18 2.3-4 Rev. 31

normal annual precipitation at Bridgeport is 43.63 inches. Since 1894, annual totals have ged from a minimum of 23.03 inches in 1964, to a maximum of 73.93 inches in 1972. Monthly ipitation totals have ranged from 0.07 inch in June 1949 to 18.77 inches in July 1897. Since 9, the maximum measured 24-hour rainfall has been 6.89 inches occurring in June 1972 AA 1971, 1990).

le 2.3-9 lists normal precipitation amounts and extreme 24-hour and monthly rainfall values ridgeport (NOAA 1970, 1974, 1975, 1978, 1981 and January - June 1982; Weather Bureau 0). Table 2.3-10 lists estimated extreme short term precipitation quantities (Hershfield 1961).

1.2.6 Extremes of Snowfall asurable snowfall has occurred in the months of November through April, although heavy wfall occurrences are usually confined to the months of December through March. The mean ual snowfall at the present Bridgeport location is 25.3 inches, with totals since 1932 ranging m 8.2 inches in the 1972-1973 season, to 71.3 inches in the 1933-1934 season. The maximum nthly snowfall, occurring in February 1934, was 47.0 inches. Since 1949, both the maximum sured snowfall in 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> (16.7 inches), and the greatest snowfall in one storm (17.7 inches) urred during the same storm in February 1969. The maximum measured snowfall in 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 7 inches) was matched again in January 1978. Snowfalls of 1.0 inch or more occur roximately 7 days annually. Table 2.3-11 gives the monthly, seasonal, and annual snowfall istics (NOAA 1971, 1990).

100-year recurrence maximum snow load is estimated to be 31 lb/sq ft (ANSI 1972).

uming a snow-to-water ratio of 8.7 to 1 (calculated using data from 10 snowstorms of

-inch precipitation or more during 1974 and 1975 (NOAA 1974-1975), the corresponding

-year snow depth is estimated to be about 52 inches. The 48-hour probable maximum winter ipitation snow accumulation is about 48 inches (Riedel et al., 1956). When added to a wpack of 52 inches, the total snow depth is about 100 inches. Snow load data available from a y conducted by the Housing and Home Finance Agency (1952) also suggests that the total ght of the 100-year recurrence maximum snow load when added to the maximum probable le storm accumulation would be about 60 lb/sq ft, or total depth of about 100 inches. (See tion 2.3.2.3.3 for design snow load information.)

1.2.7 Hailstorms ge hail, which sometimes accompanies severe thunderstorms, occurs infrequently in the lstone area. Based on a 1955 through 1967 study (Pautz 1969), hailstones with diameters ter than or equal to 0.75 inch occur at an average of 1.4 times per year in the 1-degree tude-longitude) square where the Millstone site is located. During the period of 1959 through 1, the largest hailstones observed in the 1-degree square containing the site were qualitatively cribed as baseball size, and occurred in Groton, Connecticut (5 miles northeast of the site),

May 29, 1969 (NOAA 1959-1981). Most hail reported in the area is less than 0.5 inches in meter.

28/18 2.3-5 Rev. 31

ezing rain and drizzle are occasionally observed during the months of December through ch, and only rarely observed in November and April. An average of 18.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> of freezing and 8.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> of freezing drizzle occur annually in the region. In the 32-year period, 1949 ugh 1980, all cases of freezing precipitation were reported as light (less than 0.10 inch per r), except for 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> of moderate (0.10 to 0.30 inch per hour). Table 2.3-12 presents average nthly, seasonal, and annual occurrences of freezing precipitation at Bridgeport (NOAA 9-1980).

ording to a study by Bennett (1959), based on 9 years of data, ice accumulations of greater 0.25 inch due to freezing precipitation may be expected to occur about one time per year. Ice umulations greater than 0.50 inch may be expected about once every two years. The maximum accumulation is estimated to be 1.68 inches based on Bridgeport observations (NOAA 1949 ugh 1981), and assuming a conservative average rainfall of 0.07 inch per hour.

1.2.9 Fog And Ice Fog average annual fog frequency (with visibility less than 7 miles) is 13.3 percent at Bridgeport, h the maximum monthly frequency of fog (16.4 percent) occurring in May (NOAA 9-1980). The average annual ground fog frequency is 2.2 percent, with October having the imum monthly frequency of 3.4 percent. Only 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> of heavy ice fog, a winter phenomenon, been recorded during the period of 1949 through 1980.

vy fog (visibility of 0.25 mile or less) occurs an average of 1.5 percent of the time, on about days annually (NOAA 1970, 1974, 1975, 1978, 1981), and predominantly during the months December through June. The maximum number of consecutive hours of heavy fog observed ng the period 1949 through 1964 was 26. Table 2.3-13 presents monthly, seasonal, and annual uencies of various fog conditions based on 1949 through 1980 data at Bridgeport, Connecticut AA 1949-1980).

1.2.10 High Air Pollution Potential Millstone site is in an area of relatively infrequent episodes of high air pollution potential.

continuous progression of large scale weather systems across North America frequently nges the air mass in the region and allows only infrequent extended periods of air stagnation.

ording to Holzworth (1972), high meteorological potential for air pollution occurs an average bout two times per year. A stationary high-pressure system over the eastern United States is erally the cause of these high air pollution potential days.

1.2.11 Meteorological Effects on Ultimate Heat Sink epression of water levels in Long Island Sound may result from an intense storm or hurricane ving up the Atlantic coast. The most conservatively calculated depression (NNECO 1974a) s not exceed the operable depth of safety related service water pumps in the intake structure ction 2.4).

28/18 2.3-6 Rev. 31

al meteorology for the Millstone site is described by weather observations taken over a year period (1949 through 1980) at Bridgeport and by data collected during a 8-year period 74 through 1981) by an instrumented meteorological tower at Millstone. The Bridgeport ther facility at Sikorsky Airport is located southeast of Bridgeport (an urban industrial area) about 1 mile from Long Island Sound. The Millstone meteorological tower is located on a nt of land right at the shore and is surrounded by water on three sides. The water temperatures he eastern end of Long Island Sound (Millstone area) tend to be somewhat cooler than water peratures in the western end (Bridgeport) because of water exchange with the Atlantic Ocean.

s is particularly true in the summer. In spite of these differences in location, the meteorological ditions are similar. Millstone data for a 8-year period (1974 through 1981) were compared re possible to Bridgeport data for the same period. The comparisons indicated that eorological conditions at the two locations were similar and thus that the 32-year Bridgeport base can be used to reasonably represent long-term meteorology at Millstone.

2.1 Normal and Extreme Values of Meteorological Parameters 2.1.1 Wind Conditions le 2.3-14 shows monthly and annual summaries of wind speed and direction at Bridgeport for 9 through 1980. Table 2.3-15 shows monthly and annual summaries of wind speed and ction at Millstone for 1974 through 1981, taken from the 10-meter level on the meteorological er.

le 2.3-16 compares the frequency of wind directions by quadrant at Millstone and Bridgeport the comparison period (1974 through 1980, and 1974 through 1981) and relates both to the rt-term (8-year) and long-term Bridgeport data base. There is good statistical agreement ween the sites. Table 2.3-17 compares the frequency of wind speeds by quadrant in a similar ner. Wind speeds at Bridgeport are somewhat higher; this may be due to the greater elevation he wind sensor at Bridgeport for a part of the comparison period and most of the long-term od. Nonetheless, there is reasonable agreement between the sites. Table 2.3-18 shows the ctional persistence by compass sector of 10-meter winds at Millstone from 1974 through

1. Table 2.3-5 shows the directional persistence by compass sector of winds at Bridgeport m 1949 through 1965.

2.1.2 Air Temperature and Water Vapor les 2.3-1 and 2.3-3 give the normal and extreme values of air temperature and humidity for years of Bridgeport data. Table 2.3-19 presents normal and extreme values of air temperature, point temperature, absolute humidity, and relative humidity for 19 years of Millstone data at 10-meter level. Tables 2.3-20 and 2.3-21 compare Bridgeport and Millstone data for the same period. Temperatures at Millstone are slightly cooler than at Bridgeport, probably reflecting ler water temperatures around Millstone, the presence of an urban heat island affecting dgeport, and closer proximity of the Millstone instrumentation to the shoreline. Dewpoint 28/18 2.3-7 Rev. 31

2.1.3 Precipitation les 2.3-9 through 2.3-12 give the normal and extreme values of precipitation based on long Bridgeport data. No precipitation data are collected at Millstone.

2.1.4 Fog and Smog le 2.3-13 provides a summary of fog conditions based on long term Bridgeport data. Most of heavy fog in the Millstone area is an advection type caused by the passage of warm moist air r relatively cold water. Since Millstone has greater exposure to the cooler waters of eastern g Island Sound and the Atlantic Ocean, the frequency of heavy fog there is expected to be ewhat greater than the frequency at Bridgeport. This expectation is borne out in Table 2.3-22, ch compares heavy fog occurrence at Bridgeport to that at Block Island (NOAA 1970, 1974, 5, 1978, 1981). Block Island has greater exposure to cool waters in all directions and eriences a higher frequency of heavy fog than Bridgeport. The frequency of occurrence of vy fog at Millstone is probably greater than that at Bridgeport but less than that at Block nd. The Millstone meteorological tower at one time had a visibility monitor, and joint uency summaries of visibility, wind direction, and atmospheric stability are provided for lstone data in Table 2.3-23. The visibility monitor reflects the occurrence of haze, rain, and w as well as fog and consequently may not be directly compared to either Bridgeport or Block nd fog occurrence data, which are derived from actual visual observations of fog.

le 2.3-24 provides monthly frequencies of the duration of poor visibility conditions (less than ile) as measured by the Millstone visibility monitor for a 8-year period. Similar information Bridgeport is not available.

2.1.5 Atmospheric Stability le 2.3-25 shows the percentage distribution of stability data within the seven classes specified Regulatory Guide 1.23 (Table 1.8-1) for the period 1949 through 1980 at Bridgeport. The hod used to assign a datum to a particular stability class is based on a parameterization of ming solar radiation and wind speed and is known as the STAR method. This method yields a percentage of cases in the A stability class (Pasquill classification method) at Bridgeport ause a solar angle of at least 60 degrees is required concurrent with relatively clear skies; this uirement is fulfilled only on sunny June and July days for a few hours around solar noon. Also,

, and G stabilities are constrained to occur only during nighttime hours by this program, and Bridgeport data are thus unable to reflect daytime occurrences of stable conditions such as e associated with the shallow inversions of a sea breeze.

le 2.3-26 shows the percentage distribution of stability data within seven classes for the 1974 ugh 1981 period at Millstone, based on vertical temperature difference measurement at three ls on the meteorological tower. Table 2.3-27 shows the same information, based on wind ction variance measurements at the four wind instrument levels on the tower.

28/18 2.3-8 Rev. 31

parable because of the differences in methodology.

le 2.3-29 shows cumulative frequency distributions of the duration of inversion conditions (E, nd G stability class) by month for the 1974 through 1981 data at Millstone, based on vertical perature difference measurements at three levels on the meteorological tower.

2.1.6 Seasonal and Annual Mixing Heights sonal and annual mixing height data for Millstone are adapted from Holzworth (1972) and wn in Table 2.3-30. No direct measurements of mixing height are made.

2.2 Potential Influence of the Plant and Its Facilities on Local Meteorology lstone 3 uses a once-through cooling water system, discharging its cooling water into an ting quarry, into which Millstone Units 1 and 2 also discharge, and then into Long Island nd. Thin wisps of steam fog occasionally form over the quarry and less frequently over the harge plume during the winter months, depending on tidal conditions and temperature erences between air and water. This fog dissipates rapidly as it moves away from the water

. The areal extent of the steam fog is negligible.

2.3 Local Meteorological Conditions for Design and Operating Bases 2.3.1 Design Basis Tornado design basis tornado for Millstone 3 (used for missile damage estimates) was developed from ulatory Guide 1.76 (Table 1.8-1). The specifications are as follows:

Maximum wind speed 360 mph Rotational speed 290 mph Maximum translational speed 70 mph Pressure drop 3.0 psi Rate of pressure drop 2.0 psi/sec ed on descriptions of Connecticut tornadoes (NOAA 1959-1981; Pautz 1969), a tornado more ere than this has never been recorded in Connecticut.

28/18 2.3-9 Rev. 31

design basis hurricane for Millstone (used for flooding and setdown estimates) was eloped in the Millstone 3 PSAR (NNECO 1974b). The specifications are:

Central pressure index 27.26 inches Peripheral pressure 30.56 inches Radius to maximum winds 55 miles Angle of maximum wind from direction of travel 115 degrees Maximum gradient wind 124 mph Speed of translation 17 mph s design hurricane is considerably more intense than the worst on record (Hurricane of 1938).

2.3.3 Snow Load design total snow load (Section 2.3.1.2.6) for Millstone (used for Category I building design) 0 lb/sq ft (depth of 100 inches). This is assumed to consist of a preexisting snowpack of depth nches and a 2-day winter snowstorm delivering another 52 inches. Conditions like this have been recorded on the Connecticut shoreline. The roofs of safety-related structures are gned for a snow load of 60 lb/sq ft. The roofs of nonsafety-related structures (convention) are gned for a snow load of 40 lb/sq ft which exceeds the ANSI requirement of 30 lb/sq ft.

2.3.4 Rainfall design maximum rainfall rate for Millstone (used in the original site flooding estimate) was inches in 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. Roof drainage was originally designed for a rainfall rate of 6.5 inches per

r. Site flooding and roof drainage have since been assessed for a rainfall rate of 17.4 inches in our. The maximum 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> rainfall recorded at Bridgeport was 6.89 inches in June 1972.

2.3.5 Adverse Diffusion Conditions occurrence of adverse diffusion conditions (low winds, high stabilities, sea breeze igation, long periods of directional persistence of winds, or long periods of persistence of high ilities) used for diffusion estimates at Millstone, are considered in the methodology of the usion estimates that appear in Sections 2.3.4 and 2.3.5.

2.4 Topography topography around Millstone is marked by low rolling hills rising inland from the shoreline.

maximum height of the surrounding terrain within 5 miles of the site is about 250 feet above n sea level (msl) at 3.2 miles to the north-northwest. To the south of the site, from east ugh west, is open water. Figure 2.3-1 shows the general topography of the Millstone area.

28/18 2.3-10 Rev. 31

iles to 50 miles.

3 ON-SITE METEOROLOGICAL MEASUREMENTS PROGRAM meteorological monitoring program at the Millstone site began in August 1965 to collect operational wind and temperature data for Millstone 1. The program initially consisted of ecting analog data from a 140-foot instrumented tower and manually digitizing these data into rly values which served as the basis for appropriate joint frequency distributions and ospheric diffusion analyses for both Millstone 1 and 2. After the publication of Regulatory de 1.23 (as Safety Guide 23 in 1972), the on-site meteorological program was found to be cient with respect to the requirements of this guide regarding both data recovery rates and rumentation specifications. In late 1973, a new meteorological tower which met the uirements of Regulatory Guide 1.23 was erected and instrumented. Eight full calendar years of (1974, 1981) from this new tower are used in the climatological summaries presented in this ion. The following sections refer only to the new tower and the on-site program after late 3.

992 a backup meteorological mast was installed near the EOF. The backup mast provides a ondary source of on-site meteorological data in the event data from the primary tower is not ilable. This mast consists of wind speed and direction instrumentation at the 33 foot level ve grade. Atmospheric stability can be estimated using the variance of the wind direction. The kup mast 33 foot wind data can be extrapolated upward to provide estimates of wind at heights ch correspond to the primary tower wind measurement elevations.

3.1 Measurement Locations and Elevations primary measurements are made at the meteorological tower. The tower is located on a point and about 1,200 feet south-southeast of the Millstone 1 turbine building, which is the nearest e structure. The top of this building is at elevation 105 feet, msl. The base of the tower is at roximate elevation 15 feet msl; plant grade for Millstone 1 and 2 is 14 feet msl, and for lstone 3 is 24 feet msl. The top of the tower is at 465 feet msl; the top of the Millstone stack is feet msl. Figure 1.2-1 shows the tower location with respect to plant layout. The tower sures meteorological parameters at five levels. All measurements are taken on the tower ept solar radiation which is taken to the south of the tower in a shadow-free area. Table 2.3-31 the measurements and their elevations. All measurements are continuous.

kup meteorological measurements are made at the backup meteorological mast. The base of backup mast is at 73 feet (MSL).

3.2 Meteorological Instrumentation instruments used on the tower and mast were selected for conformance with the mmendations of Regulatory Guide 1.23 and are listed in Table 2.3-32. All temperature sors are mounted in aspirated radiation shields.

28/18 2.3-11 Rev. 31

ly calibrated sensors. The removed wind speed sensors are sent to an instrument vendor for acement of worn components, recalibration to initial specifications, and certification. The oved wind direction sensors are reconditioned by an instrument technician by replacement of n components, recalibration to initial specifications, and certification. Temperature sensors temperature difference sensors are calibrated quarterly on the tower by immersion of both in baths; the resultant output is compared to 0°C.

tine inspection visits to the tower and mast are conducted by instrument technicians who cute a checklist designed to identify any instrument problems. Additionally, emergency visits made when a company meteorologist or other qualified person identifies an instrument blem through daily inspection of telemetered data. These procedures ensure prompt repair of malfunctioning instrument and a high rate of data recovery.

3.3 Data Recording Systems and Data Processing er and mast data is digitized and processed by data loggers. One data logger is located within instrument shelter at the base of the tower and receives tower and solar radiation data and one logger is located within the instrument shelter adjacent to the Site Training Facility and ives mast data. These data loggers provide digital data to the Unit 2 and Unit 3 plant process puters. The plant process computers relay this data to each of two Environmental Data uisition Network (EDAN) field minicomputers, through separate transmission paths. Tower mast data is available for display at each of these four, redundant digital recording systems.

EDAN host computer collects and saves data from all EDAN field minicomputers. Once ed on the host computer, the data are available for inspection, editing, and analysis. Data is ed on a mirrored disk system on the host computer. Periodic database backups are performed rotect against data loss. Additionally, recent data is available on each field computer for oration to the host, if necessary.

EDAN field minicomputers are checked for correct operation during scheduled inspections technicians. Emergency visits are made if inspection of telemetered data indicates the field icomputer is malfunctioning. Correct operation of the host computer is checked every work by a computer operator. Transfer of the data between the field and host computers is nitored by both a computer operator and by an automated process for detecting the failure of d computers to report to the host computer. Both field and host minicomputers undergo rous preventive maintenance programs. Troubleshooting is accomplished by on-call computer nicians. These procedures assure prompt repair of any malfunctioning component.

3.4 Quality Assurance for Meteorological System and Data ure 2.3-7 is a simplified diagram of the procedures developed to ensure that the entire path m sensor to the final data used for analyses is as free from errors as possible, that the data are of red quality, that questionable or bad data are corrected or deleted, and that an adequate rate of recovery is achieved. Table 2.3-33 shows the monthly and annual recovery rates for 8 years 28/18 2.3-12 Rev. 31

ormed and the basis for these operations, such as calibration adjustments and the deletion of during periods of instrument malfunction.

3.5 Data Analysis digital data recording system produces 15-minute average data that are directly suitable for ut into site climatology or atmospheric diffusion models.

nthly and annual joint frequency distributions of wind speed, wind direction, and atmospheric ility for each level on the meteorological tower are contained in Tables 2.3-15 and 2.3-18.

se analyses are based on Millstone data collected during 1974 through 1981. Section 2.3.2 pares these analyses with the long- term Bridgeport data (1949 through 1980). The data used repare these analyses are available in printed form or on magnetic tape and upon request may btained from the Environmental Programs Department.

4 SHORT-TERM (ACCIDENT) DIFFUSION ESTIMATES 4.1 Objective idents at Millstone 3 are assumed to result in airborne radioactive releases from various ase points. For various time periods after an accident, atmospheric diffusion factors (X/Q) e calculated for emissions from Millstone 3 at the exclusion area boundary (EAB) and low ulation zone (LPZ) for each downwind sector.

distances from each release point to the EAB in each sector are given in Table 2.3-34. The is taken to be 3860 meters in all sectors from any release point.

4.2 Calculation ident X/Q's were calculated using the basic methods of Regulatory Guide 1.145. For elevated ases, the X/Q's for the first four hours are calculated using a seabreeze fumigation model pted from Regulatory Guide 1.3. X/Q values for the control room were calculated using roved methods such as Regulatory Guide 1.194.

4.3 Results calculated X/Q's used in DBA radiological consequence calculations are presented with the of assumptions used in each calculation.

28/18 2.3-13 Rev. 31

5.1 Calculation Objective levels of radioactivity are routinely released from the Millstone stack and the MP3 vent.

ospheric Diffusion Factors (X/Q) based on site meteorological data are calculated for various nwind receptor locations of interest. The meteorological data is used to calculate the dose sequences to the public from routine airborne effluents. The calculated doses are submitted ually to the NRC.

5.2 Calculations 5.2.1 Release Points and Receptor Locations tine releases occur from both the MP3 vent and the Millstone stack. Releases from the lstone stack are considered elevated. The distances from each release point to the nearest land nearest residence in each downwind sector are listed in Table 2.3-34 and used in X/Q ulation.

5.2.2 Database culations are performed on a quarterly basis using the actual meteorology for that period.

5.2.3 Models X/Q and D/G values are calculated from hourly in-site meteorological data via methods pted from Regulatory Guide 1.111 using a conventional Gaussian plume model.

6 REFERENCES FOR SECTION 2.3 1 American National Standards Institute (ANSI) 1972. American National Standard Building Code Requirements for Minimum Design Loads in Buildings and Other Structures. New York, NY.

2 Bennett, I. 1959. Glaze, Its Meteorology and Climatology, Geographical Distribution, and Economic Effects. Technical Report EP-105. Quartermaster Research and Engineering Command, U.S. Army Environmental Protection Research Division, Office of Chief of Engineers, Washington, D.C.

3 Dunn, G. E. and Miller, B. I. 1960. Atlantic Hurricanes. Louisiana State University Press, Baton Rouge, La.

4 Hershfield, D. M. 1961. Rainfall Frequency Atlas of the United States for Durations from 30 Minutes to 24 Hours and Return Periods from 1 to 100 Years. Technical Paper No. 40, U.S. Department of Commerce, Weather Bureau, Washington, D.C.

28/18 2.3-14 Rev. 31

Agency, Office of Air Programs, Washington, D.C.

6 Ludlum, D. 1976. The Country Journal, New England Weather Book. Houghton Mifflin Co., Boston, Mass.

7 National Oceanic and Atmospheric Administration (NOAA) 1949-1980. WBAN Surface Observations (on magnetic tape) for Bridgeport, Connecticut. U.S. Department of Commerce, National Climatic Center, Asheville, NC.

8 National Oceanic and Atmospheric Administration (NOAA) 1959-1981. Storm Data.

U.S. Department of Commerce, Environmental Data Service, Asheville, NC.

9 National Oceanic and Atmospheric Administration (NOAA) 1970, 1974, 1975, 1978, 1981, 1990. Local Climatological Data. In: Annual Summary with Comparative Data, Bridgeport, Connecticut. U.S. Department of Commerce, National Climatic Center, Asheville, NC.

10 National Oceanic and Atmospheric Administration (NOAA) 1974-1975. Local Climatological Data, Bridgeport, Connecticut. U.S. Department of Commerce, Environmental Data Source (EDS), January 1974 - December 1975, Asheville, NC.

11 National Oceanic and Atmospheric Administration (NOAA) January- June 1982. Local Climatological Data. Monthly Summary Data, Bridgeport, Connecticut. U.S.

Department of Commerce, National Climatic Center, Asheville, NC.

12 Neuberger, H. 1965. Introduction to Physical Meteorology. Pennsylvania State University, p 237, University Park, Penn.

13 Northeast Nuclear Energy Company (NNECO) 1974a. Millstone Nuclear Power Station Unit 3, Preliminary Safety Analysis Report, Amendment 22, Question 2.10.

14 Northeast Nuclear Energy Company (NNECO) 1974b. Millstone Nuclear Power Station Unit 3, Preliminary Safety Analysis Report, Amendment 22, Question 2.11.

15 Pautz, M. E. (ed) 1969. Severe Local Storm Occurrences, 1955-1967. ESSA Technical Memorandum WBTM FCST 12, U.S. Department of Commerce, ESSA. Weather Analysis and Prediction Division, Weather Bureau, Silver Spring, Md.

16 Riedel, J. T.; Appleby, J. F.; and Schloemer, R. W. 1956. Seasonal Variation of the Probable Maximum Precipitation East of the 105th Meridian for Areas from 10 to 1,000 Square Miles and Durations of 6, 12, 24, and 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />. Department of Commerce, Weather Bureau, and Army Corps of Engineers, Hydrometeorological Report No. 33, Washington, D.C.

28/18 2.3-15 Rev. 31

Commerce, NOAA, National Weather Service, Asheville, NC.

18 Thom, H. C. S. 1963. Tornado Probabilities. Monthly Weather Review, p 730-731.

19 Thom, H. C. S. 1968. New Distributions of Extreme Winds in the United States.

Proceedings of the American Society of Civil Engineers, New York, NY. p 1787-1801.

20 Tverskoi, P.N. 1965. Physics of the Atmosphere, A Course in Meteorology (translated from Russian by the Israel Program for Scientific Translations). National Technical Information Service, U.S. Department of Commerce, Springfield, Va., p 527.

21 US Housing and Home Finance Agency, 1952. Snow Load Studies. Housing Research Paper 19. U.S. Department of Housing and Urban Development Headquarters, Washington, D.C.

22 US Nuclear Regulatory Commission, Office of Standards Development, Regulatory Guide 1.111, Rev. 0. Methods for Estimating Atmospheric Transport and Dispersion of Gaseous Effluents in Routine Releases from Light-Water-Cooled Reactors, Washington, D.C. March 1976.

23 US Nuclear Regulatory Commission, Calculation of Intermittent (Purge) Releases When Using Joint Frequency Data. Distributed during Public Meeting at Bethesda, Maryland, May 13, 1976.

24 US Nuclear Regulatory Commission, Office of Standards Development Regulatory Guide 1.111, Revision 1. Methods of Estimating Atmospheric Transport and Dispersion of Gaseous Effluents in Routine Releases from Light-Water-Cooled Reactors, Washington, D.C. July 1977.

25 United States Nuclear Regulatory Commission, Office of Standards Development Regulatory Guide 1.145 Rev. 0, Atmospheric Dispersion Models for Potential Accident Consequence Assessments at Nuclear Power Plants, August 1979, Washington, D.C.

26 Weather Bureau 1959. Climatography of the United States No. 60-6, Climates of the States, U.S. Department of Commerce, Conn.

27 Weather Bureau 1960. Climatography of the United States No. 10-23. In: Climatic Summary of the United States, Section 86 - Massachusetts, Rhode Island, and Connecticut U.S. Department of Commerce, Conn.

28 Viemeister, P. E. 1961. The Lightning Book. MIT Press, Cambridge, Mass, p 192-193.

29 Brumbach, J. J. 1965. The Climate of Connecticut. Dept. of Agriculture and Natural Resources, Bulletin Number 99.

28/18 2.3-16 Rev. 31

Consequences of a Loss of Coolant Accident for Boiling Water Reactors, June 1974, Washington, D.C.

31 U.S. Atomic Energy Commission, Directorate of Regulatory Standards, Regulatory Guide 1.76. Design Basis Tornado for Nuclear Power Plants, April 1974, Washington, D.C.

28/18 2.3-17 Rev. 31

OF TEMPERATURE AT BRIDGEPORT, CONN. (1901-1981)

Temperature °C (°F)

Highest Lowest Highest Lowest Average Absolute Average Absolute Monthly Monthly Normal Maximum Maximum Minimum Minimum Average Average gth of * * ** * ** *** ***

ord cember 1.0 4.7 19.4 -2.7 -24 3.8 -3.1 (33.8) (40.5) (67) (27.1) (-12) (38.8) (26.4) uary -1.0 2.7 20.0 -4.8 -26 3.8 -5.7 (30.2) (36.9) (68) (23.4) (-14) (38.8) (21.8) ruary -0.6 3.3 21.1 -4.5 -29 2.8 -9.1 (30.9) (37.9) (70) (23.9) (-20) (37.1) (15.6)

Winter -0.2 3.6 21.1 -4.0 -29 - -

(31.6) (38.4) (70) (24.8) (-20) rch 3.3 7.2 28.3 -0.7 -16 8.0 0.1 (37.9) (45.0) (83) (30.8) (3) (46.4) (32.1) ril 9.1 13.6 33.9 4.6 -13 11.8 6.3 (48.4) (56.5) (93) (40.3) (9) (53.3) (43.4) y 14.6 19.3 35.0 9.9 -2 17.3 10.6 (58.3) (66.7) (95) (49.9) (28) (63.2) (51.1)

Spring 9.0 13.4 35.0 4.6 -16 - -

(48.2) (56.1) (95) (40.3) (3) e 19.9 24.4 35.6 15.4 1 22.6 17.8 (67.9) (76.0) (96) (59.8) (34) (72.6) (64.0) y 23.2 27.5 39.4 18.9 7 25.2 21.2 (73.8) (81.5) (103) (66.1) (44) (77.4) (70.1) gust 22.6 26.9 38.3 18.3 6 24.5 20.0 (72.7) (80.4) (101) (64.9) (42) (76.1) (68.0) ummer 21.9 26.3 39.4 17.6 1 - -

(71.5) (79.3) (103) (63.6) (34) 28/18 2.3-18 Rev. 31

Temperature °C (°F)

Highest Lowest Highest Lowest Average Absolute Average Absolute Monthly Monthly Normal Maximum Maximum Minimum Minimum Average Average tember 19.2 23.6 37.2 14.7 0 21.4 16.4 (66.5) (74.5) (99) (58.4) (32) (70.5) (61.5) ober 13.8 18.4 32.2 9.2 -7 15.7 9.7 (56.8) (65.1) (90) (48.5) (20) (60.2) (49.4) vember 7.8 11.8 25.6 3.7 -13 10.3 3.6 (46.0) (53.3) (78) (38.7) (9) (50.5) (38.4)

Fall 13.6 17.9 37.2 9.2 -13 - -

(56.4) (64.3) (99) (48.5) (9)

Annual 11.1 15.3 39.4 6.8 -29 - -

(51.9) (59.5) (103) (44.3) (-20)

TES:

1941 through 1970 (30 years) (NOAA 1970, 1974, 1975, 1978, 1981) 1901 through 1181 (81 years) (NOAA 1954, 1959, 1963, 1970, 1974, 1975, 1978, 1981; Pautz 1969) 1931 through 1981 (51 years) (NOAA 1970, 1974, 1975, 1978, 1981) 28/18 2.3-19 Rev. 31

CONDITIONS AT BRIDGEPORT, CONN. (1966-1981)

Mean Number of Days Maximum Temperature Minimum Temperature 32°C 0°C 0°C -18°C (90°F) and Above (32°F) and Below (32°F) and Below (0°F) and Below cember 0 5 22

• uary 0 11 26

• ruary 0 8 24

• Winter 0 24 72

• rch 0 1 17 0 ril 0 0 4 0 y

• 0

• 0 Spring

• 1 21 0 e 1 0 0 0 y 3 0 0 0 gust 2 0 0 0 Summer 6 0 0 0 tember

• 0 0 0 ober 0 0 1 0 vember 0

• 7 0 Fall *

• 8 0 Annual 6 25 101 0 TES:

Less than 1 day every 2 years 28/18 2.3-20 Rev. 31

OF RELATIVE HUMIDITY AT BRIDGEPORT, CONN. (1949-1981)

Relative Humidity (%)

1 AM 7 AM 1 PM 7 PM Absolute Absolute (EST) (EST) (EST) (EST) Maximum Minimum gth of * ** ** ** *** ***

ord cember 72 73 62 68 100 14 uary 69 71 61 64 100 22 ruary 67 71 59 62 100 9 Winter 69 72 61 65 100 9 rch 69 72 58 62 100 11 ril 70 69 53 60 100 9 y 79 76 60 67 100 12 Spring 73 72 57 63 100 9 e 83 78 62 70 100 20 y 82 78 60 69 100 24 gust 83 79 61 71 100 24 Summer 83 78 61 70 100 20 tember 83 82 63 72 100 24 ober 77 78 60 69 100 21 vember 75 77 61 69 100 20 Fall 78 79 61 70 100 20 Annual 76 75 60 67 100 9 TES:

1968 through 1981 (14 Years) (NOAA 1970, 1974, 1975, 1978, 1981) 1966 through 1981 (16 Years) (NOAA 1978, 1981) 1949 through 1980 (26 Years; 1/1/49 through 4/30/53, 5/1/60 through 12/31/80) 28/18 2.3-21 Rev. 31

BRIDGEPORT, CONN. (1949-1980)

Frequency Distribution (%)

of Wind Direction December January February WINTER March April May SPRI N 8.7 8.2 8.8 8.6 8.6 7.0 5.4 7.0 NNE 5.5 5.2 4.9 5.2 4.9 4.1 4.2 4.4 NE 9.4 9.6 7.9 9.0 6.8 5.5 5.7 6.0 ENE 5.8 5.6 6.2 5.9 6.8 5.6 5.7 6.0 E 2.4 3.2 4.7 3.4 7.6 7.4 10.6 8.5 ESE 1.6 1.4 1.8 1.6 3.7 3.2 5.4 4.1 SE 1.2 1.1 1.6 1.3 2.1 2.3 3.4 2.6 SSE 1.3 0.9 1.1 1.1 1.6 2.2 3.0 2.3 S 1.5 1.6 1.9 1.7 3.0 4.7 5.6 4.5 SSW 1.8 2.0 2.3 2.1 3.5 5.3 6.4 5.1 SW 4.1 4.8 4.9 4.6 6.5 8.2 9.1 7.9 WSW 5.5 7.7 7.5 6.9 5.8 8.8 9.1 7.9 W 12.0 12.7 9.5 11.4 7.2 7.9 6.7 7.2 WNW 14.6 12.6 11.3 12.9 8.5 7.7 5.0 7.1 NW 12.6 12.0 13.5 12.7 11.1 8.9 5.6 8.5 NNW 9.0 8.6 9.2 8.9 9.5 8.5 5.9 8.0 Calm 3.0 2.9 2.9 2.9 2.9 2.7 3.1 2.9 Total 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 Total Hours 10,616 11,126 10,140 31,882 10,645 10,304 10,646 31,595 06/28/18 2.3-22 Rev. 31

BRIDGEPORT, CONN. (1949-1980) (CONTINUED)

Frequency Distribution

(%) of Wind Direction June July August SUMMER Sept. Oct. Nov. FALL ANNU N 5.4 5.4 7.2 6.0 8.3 9.0 8.8 8.7 7.6 NNE 3.4 3.7 5.3 4.1 7.4 6.4 6.0 6.6 5.1 NE 4.2 4.6 6.5 5.1 11.0 10.9 9.3 10.4 7.6 ENE 3.7 2.8 3.0 3.2 4.8 4.6 4.1 4.5 4.9 E 6.4 4.4 4.1 5.0 4.1 3.4 3.5 3.7 5.2 ESE 4.6 3.5 3.3 3.8 3.7 2.5 1.9 2.7 3.1 SE 3.6 3.3 3.1 3.3 2.9 2.3 1.9 2.4 2.4 SSE 3.2 3.5 3.3 3.3 2.8 2.2 1.9 2.3 2.2 S 7.5 7.8 7.3 7.5 4.6 3.4 2.7 3.5 4.3 SSW 7.6 8.3 8.3 8.1 5.2 3.7 3.0 4.0 4.8 SW 14.0 14.6 13.3 13.9 9.9 8.4 6.1 8.1 8.6 WSW 12.6 13.1 10.4 12.0 7.1 8.2 7.2 7.5 8.6 W 7.4 8.1 6.5 7.3 6.5 9.4 10.0 8.6 8.7 WNW 4.3 4.9 4.7 4.6 5.9 8.4 11.6 8.6 8.3 NW 5.1 4.8 5.6 5.1 7.0 8.1 11.0 8.7 8.8 NNW 4.2 4.3 5.1 4.5 5.9 6.9 8.9 7.2 7.2 Calm 2.8 3.1 3.3 3.1 2.8 2.4 2.4 2.5 2.9 Total 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 Total Hours 10,773 11,140 11,140 33,053 10,291 10,645 10,291 31,227 127,757 06/28/18 2.3-23 Rev. 31

SECTOR (1949-1965)

Hours of Persistence Direction 5 6 7 8 9 10 11 12 13 14 15 16 17 N 72 42 33 21 10 6 2 3 1 3 2 1 NNE 61 30 18 4 1 3 3 4 NE 107 64 55 37 24 16 16 8 4 9 5 4 4 ENE 52 38 19 11 6 8 11 3 1 1 1 E 51 29 22 14 10 6 5 4 5 2 1 1 ESE 30 22 5 9 5 3 4 SE 20 10 5 2 1 2 2 SSE 18 7 2 3 2 1 1 S 30 16 9 3 4 3 1 SSW 48 16 11 5 6 2 1 2 1 1 SW 124 67 53 28 21 9 7 3 4 1 3 2 WSW 115 74 37 18 9 11 5 4 3 3 1 1 W 70 45 37 9 13 14 1 3 2 2 2 WNW 101 59 42 31 19 5 6 4 6 2 3 2 NW 96 46 42 25 23 11 13 6 11 5 1 2 NNW 86 40 32 16 10 5 4 4 1 2 2 1 Total Persistence Episodes 1,081 605 422 233 165 106 72 50 43 30 16 16 11 06/28/18 2.3-24 Rev. 31

SECTOR (1949-1965) (CONTINUED)

Hours of Persistence Direction 19 20 21 22 23 24 25 26 27 28 29 thru 33 34 35 thru 40 41 >41 N 1 1 2 NNE 1 NE 2 2 1 1 1 1 3 ENE 1 1 1 1 E 1 1 1 1 ESE 7 SE 4 SSE 3 S 6 SSW 9 SW 1 1 3 WSW 1 2 W 1 1 WNW 1 2 NW 3 1 2 NNW 1 1 1 2 Total Persistence Episodes 8 5 4 1 1 3 0 0 2 1 0 1 0 2 2, 06/28/18 2.3-25 Rev. 31

BLE 2.3-6 MONTHLY, SEASONAL, AND ANNUAL FREQUENCY DISTRIBUTIONS OF WIND DIRECTION AT BRIDGEPORT, CONN. (1949-1980)

Frequency Distribution (%)

Wind Speed Class km/hr (mph) km/hr 1.6- 6.4- 12.8- 20.8- 30.4-(mph) 4.8 11.2 19.2 28.8 38.4 >40 Total Calm (1-3) (4-7) (8-12) (13-18) (19-24) (>25) Total Hours cember 3.0 6.1 16.2 28.1 29.8 11.2 5.6 100.0 10,616 uary 2.9 7.8 15.2 25.6 29.1 13.0 6.5 100.0 11,123 ruary 2.9 6.7 14.1 25.4 30.1 14.5 6.4 100.0 10,140 Winter 2.9 6.8 15.1 26.4 29.7 12.9 6.2 100.0 31,879 rch 2.9 6.7 13.7 26.8 29.8 13.6 6.6 100.0 10,645 ril 2.7 6.7 14.9 28.0 29.9 12.3 5.5 100.0 10,304 y 3.1 7.0 18.5 32.1 28.3 9.0 2.1 100.0 10,646 Spring 2.9 6.8 15.7 29.0 29.3 11.6 4.7 100.0 31,595 e 2.8 6.7 23.4 36.9 24.9 4.5 0.8 100.0 10,773 y 3.1 7.6 22.7 40.1 22.9 3.2 0.4 100.0 11,140 gust 3.3 8.3 21.9 38.9 23.7 3.6 0.3 100.0 11,140 ummer 3.0 7.5 22.7 38.6 23.9 3.8 0.5 100.0 33,053 tember 2.8 6.9 18.5 33.7 29.9 6.9 1.2 100.0 10,291 ober 2.4 6.3 18.0 32.6 29.3 9.0 2.06 100.0 10,645 vember 2.4 6.4 16.9 29.0 28.9 11.6 4.7 100.0 10,291 Fall 2.5 6.5 17.8 31.7 29.4 9.2 2.8 100.0 31,227 Annual 2.9 6.9 17.78 31.4 28.1 9.4 3.6 100.0 127,754 28/18 2.3-26 Rev. 31

BRIDGEPORT, CONN. (1961-1990)

Fastest-Mile Wind Direction*

Wind Speed of Fastest-Mile km/hr (mph) Wind Speed December 84.8 (53) WSW January 107 (67) NNW February 104 (65) NNW Winter 107 (67) NNW March 92.8 (58) E April 88 (55) NW May 80 (50) NNW Spring 92.8 (58) E June 60.8 (38) WNW July 64 (40) WNW August 92.8 (58) NE Summer 92.8 (58) NE September 121.3 (74) S October 92.8 (58) E November 92.8 (58) SE Fall 121.3 (74) S Annual 121.3 (74) S NOTE:

• Based on a 16-compass-point system 28/18 2.3-27 Rev. 31

BRIDGEPORT, CONN. (1951-1981)

Number of Days December

• January

• February

• Winter

• March 1 April 2 May 3 Spring 6 June 4 July 5 August 4 Summer 13 September 2 October 1 November

• Fall 3 Annual 22 NOTES:

• Less than 1 day every 2 years 28/18 2.3-28 Rev. 31

OF PRECIPITATION AT BRIDGEPORT, CONN. (1901-JUNE 1982)

Precipitation mm (inches)

Mean Number of Days with Precipitation 0.25 mm Maximum Minimum Maximum (0.01 Inch) or Normal Total Monthly Monthly in 24 Hours More gth of Record * ** ** *** ***

ember 87.4 (3.44) 250 -(9.85) 8.4 - (0.33) 93.7 -(3.69) 11 ary 68.8 (2. 71 ) 284 -(11.20) 10.0 -(0.40) 116.0 -(4.55) 11 uary 68.8 (2. 71 ) 169 -(6.65) 21.6 -(0.85) 58.7 -(2.31) 10 Winter 255.0 (8.86) - - 93.7 -(3.69) 32 ch 86.6 (3.49) 245 -(9.64) 7.4 - (0.29) 117 - (4.60) 11 l 86.1 (3.39) 239 -(9.41) 17.5 -(0.69) 84.0 -(3.32) 11 90.7 (3.57) 258.6 -(10.18) 12.4 -(0.49) 82.0 -(3.23) 11 Spring 265.4 (10.45) - - 117 -(4.60) 33 65.0 (2.56) 449.6 -(17.70) 1.8 -(0.07) 175 -(6.89) 9 87.4 (3.44) 476.8 -(18.77) 11.4 -(0.45) 151 -(5.95) 8 ust 96.5 (3.80) 337.6 -(13.29) 5.1 -(0.20) 101 -(3.97) 9 Summer 248.9 (9.80) - 175 -(6.89) 26 ember 73.2 (2.88) 359.4 -(14.15) 2.3 -(0.09) 119 -(4.67) 9 ber 70.9 (2.79) 272.3 -(10.72) 7.6 -(0.30) 109 -(4.28) 7 ember 97.3 (3.83) 259.6 -(10.22) 9.1 -(0.36) 103 -(4.07) 10 Fall 241.4 (9.50) - - 119 -(4.67) 26 ual 980.7 (38.61) - - 175 -(6.89) 117 28/18 2.3-29 Rev. 31

HOURS AND RECURRENCE INTERVALS UP TO 100 YEARS Estimated Precipitating Extremes rom (inches) at Different Recurrence Intervals iod of Rainfall 1 Year 10 Years 50 Years 100 Years minutes 22.9 (0.90) 41.9 (1.65) 53.3 (2.10) 61.0 (2.40) our 27.9 (1.10) 53.3 (2.10) 67.3 (2.65) 76.2 (3.00) ours 36.8 (1.45) 64.8 (2.55) 83.8 (3.30) 92.7 (3.65) ours 39.4 (1.55) 71.1 (2.S0) 92.7 (3.65) 103 (4.05) ours 47.0 (1.85) 90.2 (3.55) 112 (4.40) 130 (5.10) hours 62.2 (2.45) 107 (4.20) 135 (5.30) IS5 (6.10) hours 68.6 (2.70) 127 (5.00) 163 (6.40) 180 (7.10) 28/18 2.3-30 Rev. 31

OF SNOWFALL AT BRIDGEPORT, CONN. (1893-JUNE 1990)

Snow, Ice Pellets Mean Number of Maximum Maximum in Days Vith Occurrence Mean Total Monthly 24 Hours of 2.51 cm (1.0 Inch) cm (Inches) cm (Inches) cm (Inches) or More Length of Record * ** *

• December 11.8 (4.6) 65.5 (25.8) 19.8 (7.8) 2 January 19.5 (7.6) 77.0 (30.3) 42.4 (16.7) 2 February 19.0 (7.4) 119.4 (47.0) 42.4 (16.7) 2 Winter 50.3 (19.6) 6 March 11.5 (4.5) 92.0 (35.9) 28.2 (11.1) 1 April 1.3 (0.5) 20.5 (8.0) 15.4 (6.0) +

May T T T 0 Spring 12.8 (5.0) 1 June 0.0 0.0 0.0 0 July 0.0 0.0 0.0 0 August 0.0 0.0 0.0 0 Summer 0.0 0 September 0.0 0.0 0.0 0 October T 2.5 (1.0) 1.3 (.5) 0 November 1.5 (0.6) 84.5 (32.2) 16.9 (6.6) +

Fall 1.5 (0.6) +

Annual 64.6 (25.2) 119.4 (47.0) 42.4 (16.7) 7 NOTES:

T = trace

+Less than 1 day every 2 years

• 1949 through 1990 (41 years) (NOAA 1990)

• • 1893 through 1990 (97 years) (NOAA 1990, Brumbach 1965) 28/18 2.3-31 Rev. 31

RAIN AND DRIZZLE AT BRIDGEPORT, CONN. (1949-1980)

Freezing Rain Freezing Drizzle (hr) (hr)

Light* Moderate** Light*

December 5.4 0.1 2.9 January 7.7 0.0 2.7 February 3.3 0.0 1.5 Winter 16.4 0.1 7.1 March 2.0 0.0 1.3 April 0.1 0.0 0.0 May 0.0 0.0 0.0 Spring 2.1 0.0 1.3 June 0.0 0.0 0.0 July 0.0 0.0 0.0 August 0.0 0.0 0.0 Summer 0.0 0.0 0.0 September 0.0 0.0 0.0 October 0.0 0.0 0.0 November 0.1 0.0 0.1 Fall 0.1 0.0 0.1 Annual 18.5 0.1 8.5 NOTES:

• Less than 2.54 mm (0.1 inch) per hour

• • 2.54 to 7.62 mm (0.1 to 0.3 inch) per hour 28/18 2.3-32 Rev. 31

FREQUENCIES (PERCENT) OF VARIOUS FOG CONDITIONS (1949-1980) AT BRIDGEPORT, CONNECTICUT Ground Heavy Fog Fog Fog Average Average Average Total Number No. of Freq. No. of Freq. No. of Freq. of Sample Hours (%) Hours (%) Hours (%) Observations ecember 106 14.3 12 1.6 16 2.2 10,664 nuary 111 14.9 14 1.9 15 2.0 11,160 bruary 88 13.1 7 1.1 13 1.9 10,163 Winter 305 14.1 32 1.5 43 2.0 31,987 arch 107 14.4 11 1.5 16 2.1 10,664 pril 95 13.2 8 1.1 12 1.6 10,320 ay 122 16..4 13 1.7 24 3.2 10,664 Spring 325 14.7 31 1.4 51 2.3 31,648 ne 109 15.1 22 3.0 15 2.1 10,320 ly 92 12.4 21 2.8 7 0.9 10,664 ugust 100 13.5 24 3.2 3 0.4 10,664 Summer 300 13.6 66 3.0 24 1.1 31,648 ptember 80 11.1 22 3.0 2 0.3 10,320 ctober 67 9.0 25 3.4 7 0.9 10,664 ovember 85 11.8 14 2.0 4 0.5 10,320 Fall 232 10.6 61 2.8 13 0.6 31,304 nnual 1,165 13.3 193 2.2 131 1.5 126,587 28/18 2.3-33 Rev. 31

SPEED DISTRIBUTIONS FOR SURFACE WINDS, AT BRIDGEPORT, CONN. (1949-1980)

A. JANUARY Wind Speed Distribution (%) Within Wind Speed Class 1.6- 6.4- 12.8- 20.8- 30.4-km/hr 4.8 11.2 19.2 28.8 38.4 >40 All Wind Direction (mph) (1-3) (4-7) (8-12) (13-18) (19-24) (25) Speeds N 0.76 1.46 2.54 2.46 0.73 0.26 8.22 NNE 0.64 1.12 1.55 1.29 0.43 0.16 5.18 NE 1.45 1.82 2.51 2.21 1.20 0.41 9.60 ENE 0.64 1.07 1.59 1.61 0.40 0.32 5.64 E 0.35 0.58 0.96 0.76 0.38 0.19 3.22 ESE 0.22 0.34 0.43 0.30 0.12 0.04 1.44 SE 0.20 0.26 0.35 0.16 0.07 0.01 1.05 SSE 0.20 0.31 0.19 0.11 0.05 0.03 0.87 S 0.21 0.40 0.38 0.21 0.18 0.23 1.60 SSW 0.19 0.38 0.62 0.47 0.22 0.12 1.99 SW 0.46 0.92 1.37 1.38 0.54 0.14 4.80 WSW 0.33 1.03 1.95 2.40 1.44 0.55 7.69 W 0.58 1.31 3.22 4.67 1.88 0.98 12.65 WNW 0.42 1.31 3.15 4.58 2.11 1.05 12.62 NW 0.78 1.47 2.70 3.90 1.94 1.12 12.00 NNW 0.36 1.41 2.09 2.57 1.35 0.78 8.56 All Sectors 7.78 15.16 25.58 29.08 13.03 6.47 Calm = 2.89 28/18 2.3-34 Rev. 31

BRIDGEPORT, CONN. (1949-1980) (CONTINUED)

B. FEBRAURY Wind Speed Distribution (%) Within Wind Speed Class 1.6- 6.4- 12.8- 20.8- 30.4-km/hr 4.8 11.2 19.2 28.8 38.4 >40 All Wind Direction (mph) (1-3) (4-7) (8-12) (13-18) (19-24) (25) Speeds N 0.78 1.44 2.46 2.66 0.97 0.50 8.81 NNE 0.57 0.82 1.20 1.52 0.61 0.22 4.94 NE 0.89 1.46 2.29 2.35 0.71 0.22 7.91 ENE 0.39 0.79 1.43 2.10 0.95 0.51 6.16 E 0.30 0.30 0.80 1.22 1.31 0.74 4.68 ESE 0.13 0.48 0.67 0.39 0.16 0.02 1.84 SE 0.25 0.49 0.41 0.32 0.11 0.01 1.59 SSE 0.17 0.27 0.37 0.19 0.07 0.04 1.10 S 0.30 0.27 0.68 0.34 0.16 0.18 1.91 SSW 0.34 0.59 0.59 0.53 0.17 0.09 2.31 SW 0.43 0.97 1.61 1.37 0.33 0.16 4.86 WSW 0.29 1.20 2.23 2.47 1.08 0.26 7.52 W 0.34 1.19 2.94 3.06 1.39 0.61 9.53 WNW 0.41 1.05 2.55 3.89 2.41 1.02 11.32 NW 0.69 1.18 2.41 4.82 3.00 1.42 13.52 NNW 0.40 1.08 2.38 2.83 1.65 0.83 9.16 All Sectors 6.66 14.07 25.43 30.13 14.48 6.38 Calm = 2.85 28/18 2.3-35 Rev. 31

BRIDGEPORT, CONN. (1949-1980) (CONTINUED)

C. MARCH Wind Speed Distribution (%) Within Wind Speed Class 1.6- 6.4- 12.8- 20.8- 30.4-km/hr 4.8 11.2 19.2 28.8 38.4 >40 All Wind Direction (mph) (1-3) (4-7) (8-12) (13-18) (19-24) (25) Speeds N 0.47 1.10 2.37 3.11 1.18 0.34 8.57 NNE 0.48 1.11 1.70 1.20 0.30 0.15 4.94 NE 0.96 1.43 1.90 1.69 0.57 0.22 6.76 ENE 0.52 0.98 1.78 2.03 0.81 0.65 6.75 E 0.28 0.90 1.92 2.45 1.27 0.79 7.61 ESE 0.25 0.63 1.15 1.14 0.44 0.13 3.74 SE 0.19 0.56 0.80 0.43 0.11 0.00 2.09 SSE 0.18 0.39 0.53 0.32 0.10 0.10 1.62 S 0.42 0.67 0.92 0.58 0.34 0.09 3.03 SSW 0.23 0.49 1.08 1.13 0.46 0.11 3.50 SW 0.55 1.21 2.41 1.75 0.40 0.12 6.45 WSW 0.53 0.83 2.04 1.65 0.55 0.17 5.76 W 0.44 0.95 2.30 2.05 0.94 0.52 7.20 WNW 0.39 0.71 1.67 2.75 1.78 1.17 8.47 NW 0.46 0.80 2.10 4.01 2.48 1.27 11.12 NNW 0.39 0.90 2.12 3.50 1.84 0.76 9.52 All Sectors 6.73 13.65 26.78 29.79 13.57 6.60 Calm = 2.88 28/18 2.3-36 Rev. 31

BRIDGEPORT, CONN. (1949-1980) (CONTINUED)

D. APRIL Wind Speed Distribution (%) Within Wind Speed Class 1.6- 6.4- 12.8- 20.8- 30.4-km/hr 4.8 11.2 19.2 28.8 38.4 >40 All Wind Direction (mph) (1-3) (4-7) (8-12) (13-18) (19-24) (25) Speeds N 0.57 1.03 2.00 2.59 0.74 0.10 7.03 NNE 0.44 0.79 1.37 1.23 0.15 0.08 4.05 NE 0.64 0.97 1.83 1.47 0.50 0.10 5.49 ENE 0.35 0.96 1.20 1.76 0.87 0.44 5.58 E 0.39 0.86 2.00 2.34 1.13 0.71 7.42 ESE 0.22 0.62 1.04 0.90 0.28 0.11 3.17 SE 0.35 0.63 0.76 0.52 0.08 0.00 2.34 SSE 0.16 0.56 0.97 0.45 0.07 0.03 2.23 S 0.39 0.88 1.75 1.20 0.40 0.11 4.73 SSW 0.37 0.77 1.32 1.84 0.85 0.21 5.34 SW 0.64 1.36 2.50 2.85 0.74 0.11 8.20 WSW 0.51 1.45 3.24 2.66 0.76 0.21 8.82 W 0.38 1.36 2.83 2.16 0.76 0.39 7.87 WNW 0.38 0.82 1.50 2.30 1.63 1.04 7.66 NW 0.52 0.84 1.75 2.90 1.68 1.22 8.91 NNW 0.40 1.04 1.99 2.71 1.72 0.62 8.47 All Sectors 6.67 14.93 28.04 29.88 12.33 5.46 Calm = 2.69 28/18 2.3-37 Rev. 31

BRIDGEPORT, CONN. (1949-1980) (CONTINUED)

E. MAY Wind Speed Distribution (%) Within Wind Speed Class 1.6- 6.4- 12.8- 20.8- 30.4-km/hr 4.8 11.2 19.2 28.8 38.4 >40 All Wind Direction (mph) (1-3) (4-7) (8-12) (13-18) (19-24) (25) Speeds N 0.51 1.09 1.81 1.55 0.39 0.09 5.44 NNE 0.43 1.01 1.39 1.02 0.27 0.09 4.23 NE 0.63 1.43 1.65 1.44 0.48 0.06 5.68 ENE 0.28 1.15 1.75 2.03 0.36 0.16 5.72 E 0.46 1.42 3.56 3.93 0.91 0.27 10.55 ESE 0.26 1.27 2.00 1.53 0.28 0.09 5.43 SE 0.52 0.89 1.22 0.60 0.12 0.06 3.41 SSE 0.32 0.73 1.16 0.66 0.12 0.01 3.00 S 0.38 1.36 1.93 1.37 0.49 0.11 5.64 SSW 0.37 1.09 2.13 1.99 0.81 0.06 6.44 SW 0.63 1.31 3.49 2.86 0.74 0.06 9.08 WSW 0.40 1.36 3.64 2.85 0.73 0.12 9.09 W 0.48 1.60 2.40 1.59 0.44 0.15 6.65 WNW 0.38 0.86 1.28 1.42 0.79 0.33 5.04 NW 0.59 0.92 1.17 1.64 0.94 0.33 5.60 NNW 0.34 1.01 1.49 1.85 1.14 0.09 5.93 All Sectors 6.96 18.50 32.07 28.32 9.01 2.08 Calm = 3.07 28/18 2.3-38 Rev. 31

BRIDGEPORT, CONN. (1949-1980) (CONTINUED)

F. JUNE Wind Speed Distribution (%) Within Wind Speed Class 1.6- 6.4- 12.8- 20.8- 30.4-km/hr 4.8 11.2 19.2 28.8 38.4 >40 All Wind Direction (mph) (1-3) (4-7) (8-12) (13-18) (19-24) (25) Speeds N 0.48 1.51 1.80 1.21 0.33 0.06 5.38 NNE 0.35 1.24 1.02 0.73 0.05 0.01 3.41 NE 0.71 1.04 1.31 0.98 0.17 0.03 4.22 ENE 0.35 0.91 1.23 0.96 0.25 0.05 3.74 E 0.45 1.39 2.27 1.73 0.45 0.10 6.38 ESE 0.30 1.08 2.00 0.88 0.27 0.05 4.57 SE 0.44 1.18 1.32 0.63 0.06 0.00 3.59 SSE 0.29 1.07 1.43 0.38 0.03 0.00 3.19 S 0.60 1.86 2.90 1.83 0.31 0.02 7.51 SSW 0.29 1.45 3.02 .240 0.38 0.07 7.60 SW 0.62 2.89 5.84 4.19 0.39 0.03 13.95 WSW 0.55 2.58 3.84 3.29 0.36 0.03 12.64 W 0.32 2.11 3.21 1.63 0.14 0.01 7.42 WNW 0.26 1.17 1.22 1.13 0.36 0.14 4.28 NW 0.39 0.98 1.24 1.73 0.58 0.18 5.09 NNW 0.33 0.96 1.23 1.24 0.43 0.05 4.23 All Sectors 6.69 23.40 36.85 24.92 4.53 0.81 Calm = 2.89 28/18 2.3-39 Rev. 31

BRIDGEPORT, CONN. (1949-1980) (CONTINUED)

G. JULY Wind Speed Distribution (%) Within Wind Speed Class 1.6- 6.4- 12.8- 20.8- 30.4-km/hr 4.8 11.2 19.2 28.8 38.4 >40 All Wind Direction (mph) (1-3) (4-7) (8-12) (13-18) (19-24) (25) Speeds N 0.49 1.71 2.02 1.04 0.14 0.02 5.40 NNE 0.69 1.12 1.32 0.49 0.07 0.00 3.69 NE 0.76 1.38 1.51 0.78 0.12 0.00 4.55 ENE 0.33 0.68 0.97 0.70 0.14 0.00 2.83 E 0.39 0.82 1.69 1.12 0.26 0.14 4.42 ESE 0.19 0.75 1.60 0.72 0.23 0.00 3.48 SE 0.28 0.93 1.53 0.51 0.01 0.00 3.26 SSE 0.35 0.98 1.60 0.54 0.01 0.00 3.47 S 0.45 1.68 3.46 1.95 0.25 0.00 7.78 SSW 0.29 1.33 3.25 3.12 0.35 0.00 8.33 SW 0.64 2.58 6.80 4.24 0.34 0.01 14.60 WSW 0.64 2.70 6.30 3.15 0.26 0.03 13.08 W 0.67 2.52 3.62 1.16 0.14 0.02 8.12 WNW 0.46 1.39 1.50 1.15 0.29 0.10 4.88 NW 0.66 1.07 1.49 1.11 0.35 0.07 4.76 NNW 0.33 1.07 1.44 1.17 0.21 0.05 4.26 All Sectors 7.61 22.70 40.07 22.94 3.16 0.43 Calm = 3.09 28/18 2.3-40 Rev. 31

BRIDGEPORT, CONN. (1949-1980) (CONTINUED)

H. AUGUST Wind Speed Distribution (%) Within Wind Speed Class 1.6- 6.4- 12.8- 20.8- 30.4-km/hr 4.8 11.2 19.2 28.8 38.4 >40 All Wind Direction (mph) (1-3) (4-7) (8-12) (13-18) (19-24) (25) Speeds N 0.93 2.28 2.62 1.12 0.22 0.01 7.17 NNE 0.91 1.45 1.86 0.98 0.05 0.02 5.26 NE 1.28 1.64 1.86 1.52 0.20 0.01 6.51 ENE 0.31 0.78 0.93 0.82 0.15 0.00 2.99 E 0.39 0.76 1.51 1.21 0.26 0.01 4.14 ESE 0.27 0.66 1.28 0.95 0.11 0.03 3.30 SE 0.26 0.91 1.21 0.63 0.04 0.01 3.05 SSE 0.26 0.81 1.63 0.54 0.04 0.01 3.28 S 0.49 1.82 3.30 1.54 0.11 0.01 7.28 SSW 0.40 1.27 3.63 2.62 0.34 0.02 8.27 SW 0.52 2.28 5.83 4.20 0.41 0.02 13.26 WSW 0.40 1.84 4.60 3.05 0.49 0.04 10.41 W 0.37 1.37 3.32 1.14 0.28 0.00 6.48 WNW 0.39 1.15 1.86 1.00 0.28 0.02 4.69 NW 0.70 1.34 1.80 1.27 0.38 0.09 5.57 NNW 0.46 1.52 1.72 1.13 0.24 0.04 5.10 All Sectors 8.32 21.88 38.93 23.72 3.59 0.31 Calm = 3.25 28/18 2.3-41 Rev. 31

BRIDGEPORT, CONN. (1949-1980) (CONTINUED)

I. SEPTEMBER Wind Speed Distribution (%) Within Wind Speed Class 1.6- 6.4- 12.8- 20.8- 30.4-km/hr 4.8 11.2 19.2 28.8 38.4 >40 All Wind Direction (mph) (1-3) (4-7) (8-12) (13-18) (19-24) (25) Speeds N 0.83 2.14 2.87 1.96 0.39 0.07 8.25 NNE 0.97 1.94 2.20 1.69 0.49 0.12 7.41 NE 1.11 2.21 3.41 3.43 0.69 0.19 11.03 ENE 0.23 0.65 1.41 1.77 0.63 0.14 4.83 E 0.16 0.64 1.18 1.57 0.44 0.12 4.10 ESE 0.18 0.63 1.23 1.31 0.31 0.05 3.71 SE 0.25 0.66 1.15 0.75 0.08 0.02 2.91 SSE 0.19 0.55 1.28 0.62 0.11 0.02 2.77 S 0.21 1.04 1.95 1.16 0.19 0.02 4.57 SSW 0.22 0.76 1.65 1.77 0.67 0.17 5.24 SW 0.45 1.40 3.47 3.76 0.76 0.07 9.90 WSW 0.15 0.86 2.60 2.95 0.54 0.02 7.12 W 0.24 0.94 3.04 1.87 0.34 0.06 6.49 WNW 0.28 1.11 2.35 1.76 0.36 0.07 5.93 NW 0.82 1.79 1.97 1.89 0.42 0.11 6.99 NNW 0.66 1.21 1.90 1.65 0.51 0.01 5.93 All Sectors 6.94 18.52 33.66 29.91 6.91 1.22 Calm = 2.84 28/18 2.3-42 Rev. 31

BRIDGEPORT, CONN. (1949-1980) (CONTINUED)

J. OCTOBER Wind Speed Distribution (%) Within Wind Speed Class 1.6- 6.4- 12.8- 20.8- 30.4-km/hr 4.8 11.2 19.2 28.8 38.4 >40 All Wind Direction (mph) (1-3) (4-7) (8-12) (13-18) (19-24) (25) Speeds N 0.68 2.39 2.93 2.30 0.58 0.08 8.95 NNE 0.80 1.69 2.36 1.25 0.27 0.04 6.41 NE 1.03 2.18 3.30 3.44 0.83 0.10 10.88 ENE 0.31 0.65 1.46 1.45 0.52 0.17 4.55 E 0.21 0.66 0.96 0.94 0.46 0.22 3.44 ESE 0.22 0.32 0.85 0.74 0.24 0.14 2.50 SE 0.28 0.55 0.81 0.54 0.14 0.01 2.33 SSE 0.24 0.65 0.81 0.36 0.09 0.05 2.19 S 0.23 0.83 1.43 0.71 0.12 0.04 3.38 SSW 0.22 0.72 1.25 1.15 0.32 0.07 3.72 SW 0.41 1.19 2.72 3.02 0.77 0.24 8.35 WSW 0.28 0.85 2.73 3.11 0.88 0.35 8.20 W 0.24 1.17 3.27 3.46 0.97 0.26 9.37 WNW 0.23 1.34 3.12 2.57 0.86 0.26 8.38 NW 0.48 1.47 2.44 2.42 1.00 0.32 8.13 NNW 0.41 1.35 2.13 1.79 0.95 0.24 6.89 All Sectors 6.26 18.01 32.56 29.26 8.99 2.57 Calm = 2.35 28/18 2.3-43 Rev. 31

BRIDGEPORT, CONN. (1949-1980) (CONTINUED)

K. NOVEMBER Wind Speed Distribution (%) Within Wind Speed Class 1.6- 6.4- 12.8- 20.8- 30.4-km/hr 4.8 11.2 19.2 28.8 38.4 >40 All Wind Direction (mph) (1-3) (4-7) (8-12) (13-18) (19-24) (25) Speeds N 0.97 2.15 2.93 1.95 0.56 0.20 8.77 NNE 0.67 1.70 2.00 1.30 0.25 0.06 5.99 NE 1.07 1.95 2.94 2.58 0.54 0.17 9.25 ENE 0.26 0.68 1.04 1.29 0.54 0.24 4.06 E 0.22 0.48 0.75 0.91 0.54 0.56 3.47 ESE 0.13 0.45 0.51 0.40 0.30 0.15 1.92 SE 0.25 0.42 0.57 0.34 0.19 0.12 1.90 SSE 0.15 0.41 0.68 0.53 0.07 0.04 1.88 S 0.20 0.58 1.00 0.65 0.16 0.07 2.66 SSW 0.07 0.39 0.97 1.08 0.35 0.13 2.98 SW 0.32 0.80 1.81 2.22 0.65 0.29 6.08 WSW 0.25 0.85 2.40 2.53 1.11 0.40 7.17 W 0.20 1.14 3.07 3.54 1.59 0.48 10.02 WNW 0.45 1.34 3.63 4.03 1.58 0.54 11.58 NW 0.71 2.03 2.83 2.94 1.85 0.62 10.98 NNW 0.49 1.56 2.22 2.62 1.34 0.63 8.86 All Sectors 6.41 16.92 28.99 28.92 11.64 4.69 Calm = 2.43 28/18 2.3-44 Rev. 31

BRIDGEPORT, CONN. (1949-1980) (CONTINUED)

L. DECEMBER Wind Speed Distribution (%) Within Wind Speed Class 1.6- 6.4- 12.8- 20.8- 30.4-km/hr 4.8 11.2 19.2 28.8 38.4 >40 All Wind Direction (mph) (1-3) (4-7) (8-12) (13-18) (19-24) (25) Speeds N 0.83 2.04 2.69 2.27 0.66 0.25 8.72 NNE 0.61 1.52 1.66 1.25 0.40 0.03 5.46 NE 0.91 .86 2.57 3.06 0.84 0.14 9.38 ENE 0.35 1.06 1.63 2.04 0.49 0.24 5.81 E 0.17 0.58 0.71 0.56 0.20 0.23 2.43 ESE 0.14 0.38 0.44 0.23 0.17 0.20 1.55 SE 0.24 0.30 0.34 0.26 0.07 0.00 1.21 SSE 0.10 0.38 0.25 0.37 0.19 0.03 1.31 S 0.12 0.49 0.41 0.31 0.14 0.04 1.52 SSW 0.13 0.33 0.56 0.57 0.13 0.12 1.84 SW 0.29 0.63 1.36 1.14 0.54 0.12 4.08 WSW 0.27 0.84 1.64 1.73 0.63 0.34 5.45 W 0.30 1.06 3.67 4.46 1.75 0.77 12.02 WNW 0.36 1.53 4.38 5.07 2.20 1.07 14.61 NW 0.71 1.67 3.19 3.99 1.89 1.12 12.57 NNW 0.55 1.52 2.59 2.52 0.92 0.90 9.00 All Sectors 6.09 16.16 28.08 29.82 11.22 5.59 Calm = 3.04 28/18 2.3-45 Rev. 31

BRIDGEPORT, CONN. (1949-1980) (CONTINUED)

M. ANNUAL Wind Speed Distribution (%) Within Wind Speed Class 1.6- 6.4- 12.8- 20.8- 30.4-km/hr 4.8 11.2 19.2 28.8 38.4 >40 All Wind Direction (mph) (1-3) (4-7) (8-12) (13-18) (19-24) (25) Speeds N 0.69 1.69 2.41 2.01 0.57 0.16 7.53 NNE 0.63 1.29 1.63 1.16 0.28 0.08 5.06 NE 0.95 1.61 2.24 2.07 0.57 0.14 7.58 ENE 0.36 0.86 1.36 1.54 0.50 0.24 4.87 E 0.31 0.83 1.56 1.57 0.58 0.30 5.14 ESE 0.21 0.64 1.10 0.79 0.24 0.08 3.06 SE 0.29 0.65 0.88 0.47 0.09 0.02 2.40 SSE 0.22 0.60 0.91 0.42 0.08 0.03 2.25 S 0.34 1.00 1.69 1.00 0.24 0.08 4.33 SSW 0.26 0.80 169 1.57 0.42 0.10 4.83 SW 0.50 1.47 3.30 2.76 0.55 0.11 8.69 WSW 0.38 1.37 3.27 2.66 0.73 0.21 8.62 W 0.38 1.40 3.08 2.57 0.88 035 8.67 WNW 0.37 1.15 2.35 2.63 1.21 0.56 8.27 NW 0.63 1.29 2.09 2.70 1.36 0.66 8.73 NNW 0.42 1.22 1.93 2.12 1.01 0.41 7.12 All Sectors 6.93 17.87 31.51 28.01 9.31 3.52 Calm = 2.85 28/18 2.3-46 Rev. 31

TABLE 2.3-15 MONTHLY AND ANNUAL WIND DIRECTION AND SPEED DISTRIBUTIONS FOR 33-FOOT WINDS AT MILLSTONE (1974-1981)

CLICK HERE TO SEE TABLE 2.3-15 28/18 2.3-47 Rev. 31

BY QUADRANT AT BRIDGEPORT, CONN. AND MILLSTONE Wind Frequency Percentage by Quadrant Onshore Offshore Valid Data Data (Hours) Period ESE-S SSW-W WNW-N NNE-E Calm lstone* 58,193 1/1/74- 15.3 31.9 33.6 17.9 1.3 12/31/80 lstone* 66,392 1/1/74- 15.3 31.4 34.2 17.8 1.2 12/31/81 dgeport** 21,882 1/1/74- 12.2 34.5 31.3 20.1 1.9 12/31/80 dgeport** 127,933 1/1/49- 12.0 30.8 31.6 22.7 2.9 04/30/53 05/01/60-12/31/80 TES:

ind direction measured at the 33-foot tower level Observations recorded every third hour beginning March 1, 1965 28/18 2.3-48 Rev. 31

BRIDGEPORT, CONN. AND MILLSTONE Wind Frequency Percentage by Quadrant Onshore Offshore Valid Data (Hours) Data Period ESE-S SSW-W WNW-N NNE-E lstone* 58,193 1/1/74- 13.7 18.0 15.0 14.2 12/31/80 (8.5) (11.2) (9.3) (8.8) lstone* 66,392 1/1/74- 13.7 17.9 15.1 13.8 12/31/81 (8.5) (11.1) (9.4) (8.6) dgeport** 21,882 1/1/74- 16.1 19.5 21.1 19.3 12/31/81 (10.0) (12.1) (13.1) (12.0) dgeport** 127,933 1/1/49- 16.3 19.0 20.6 18.7 04/30/53 (10.2) (11.9) (12.9) (11.6) 05/01/60-12/31/80 TES:

ind direction measured at the 33-foot tower level Observation recorded every third hour beginning March 1, 1965 Wind speed measured at 48 feet above ground level until 6/19/61, at 84 feet above ground from 6/19/61 to 4/18/74, and 33 feet above ground from 4/18/74 to 12/31/78 28/18 2.3-49 Rev. 31

ABLE 2.3-18 OCCURRENCE OF WIND PERSISTENCE EPISODES WITHIN THE SAME 22.5-DEGREE SECTOR AT MILLSTONE (1974-1981)

CLICK HERE TO SEE TABLE 2.3-18 28/18 2.3-50 Rev. 31

A. Monthly and Annual Ambient Temperature Average Daily Average Daily Extreme Extreme Average Daily Mean Maximum Minimum Maximum Minimum Month °C (°F) °C (°F) °C (°F) °C (°F) °C (°F)

January -1.0 (30.3) 2.4 (36.4) -4.5 (23.8) 14.7 (58.5) -19.4 (-2.9)

February -0.3 (31.5) 3.0 (37.3) -3.6 (25.5) 16.9 (62.4) -19.3 (-2.7)

March 3.1 (37.5) 6.4 (43.5) -0.1 (31.8) 23.3 (73.9) -14.0 (6.8)

April 7.7 (45.8) 11.0 (51.8) 4.7 (40.4) 27.3 (81.1) -5.6 (21.9)

May 12.4 (54.3) 15.8 (60.5) 9.5 (49.0) 29.7 (85.5) 1.0 (33.8)

June 17.1 (62.8) 20.3 (68.6) 14.2 (57.5) 31.8 (89.2) 6.6 (43.9)

July 20.5 (69.0) 23.4 (74.1) 18.0 (64.3) 32.8 (91.0) 10.5 (50.9)

August 20.7 (69.3) 23.4 (74.1) 17.9 (64.3) 32.2 (90.0) 8.9 (48.0)

September 17.7 (63.8) 20.5 (68.9) 14.1 (57.4) 29.6 (85.3) 3.4 (38.1)

October 12.4 (54.3) 15.6 (60.0) 8.5 (47.2) 26.3 (79.3) -1.8 (28.8)

November 7.5 (45.6) 10.7 (51.2) 4.1 (39.3) 22.7 (72.9 -9.1 (15.6)

December 2.0 (35.6) 5.3 (41.5) -1.5 (29.4) 20.1 (68.1) -20.6 (-5.1) 1/1/74 - 12/31/00 10.0 (50.0) 13.1 (55.7) 6.8 (44.2) 32.8 (91.0) -20.6 (-5.1) 06/28/18 2.3-51 Rev. 31

B. Monthly and Annual Dew Point Average Daily Average Daily Extreme Average Daily Mean Maximum Minimum Maximum Extreme Minimum Month °C (°F) °C (°F) °C (°F) °C (°F) °C (°F)

January -5.8 (21.5) -1.7 (28.9) -9.8 (14.4) 12.6 (54.7) -29.0 (-20.2)

February -5.5 (22.0) -1.8 (28.8) -9.2 (15.5) 10.1 (50.2) -24.1 (-11.4)

March -3.0 (26.7) 0.8 (33.4) -6.5 (20.3) 13.0 (55.4) -24.6 (-12.3)

April 1.2 (34.1) 4.4 (40.0) -2.1 (28.2) 14.5 (58.1) -17.0 (1.4)

May 6.6 (43.8) 9.5 (49.1) 3.8 (38.8) 19.3 (66.7) -10.4 (13.4)

June 11.7 (53.1) 14.4 (57.9) 9.2 (48.5) 22.2 (72.0) -3.3 (26.1)

July 15.1 (59.1) 17.5 (63.5) 12.8 (55.0) 24.7 (76.5) 2.4 (36.3)

August 15.5 (60.0) 17.9 (64.3) 13.1 (55.6) 24.3 (75.7) 0.3 (32.5)

September 12.0 (53.7) 14.9 (58.9) 9.3 (48.7) 24.4 (75.9) -3.3. (26.1)

October 6.1 (43.0) 9.5 (49.1) 2.9 (37.2) 20.4 (68.7) -11.9 (10.6)

November 1.5 (34.7) 5.0 (41.0) -2.0 (28.3) 16.6 (61.9) -16.9 (1.6)

December -3.5 (25.7) 0.5 (32.9) -7.2 (19.0) 13.6 (56.5) -29.3 (-20.7) 1/1/74 - 12/31/00 4.3 (39.8) 7.6 (45.6) 1.2 (34.1) 24.7 (76.5) -29.3 (-20.7) 06/28/18 2.3-52 Rev. 31

C. Monthly and Annual Absolute Humidity Average Daily Average Daily Extreme Average Daily Mean Maximum Minimum Maximum Extreme Minimum Month °C (°F) °C (°F) °C (°F) °C (°F) °C (°F)

January 3.3 4.3 2.4 11.1 0.5 February 3.3 4.3 2.5 9.5 0.8 March 4.0 5.1 3.1 11.3 0.7 April 5.3 6.6 4.2 12.4 1.4 May 7.6 9.1 6.3 16.6 2.3 June 10.5 12.4 9.0 19.6 3.8 July 12.9 15.0 11.2 22.7 5.7 August 13.3 15.3 11.5 22.1 4.9 September 10.7 12.8 9.0 22.3 3.8 October 7.3 9.1 5.9 17.7 2.0 November 5.4 6.9 4.2 14.1 1.4 December 3.8 5.1 3.0 11.8 0.5 1/1/74 - 12/31/00 7.3 8.8 6.0 22.7 0.5 06/28/18 2.3-53 Rev. 31

D. Monthly and Annual Relative Humidity Average Daily Average Daily Extreme Average Daily Mean Maximum Minimum Maximum Extreme Minimum Month °C (°F) °C (°F) °C (°F) °C (°F) °C (°F)

January 71.2 85.7 56.4 100.0 18.1 February 68.9 84.4 53.3 100.0 16.0 March 67.0 82.9 50.7 100.0 14.8 April 66.2 82.4 49.3 100.0 14.1 May 69.8 85.1 53.5 100.0 14.7 June 72.4 87.1 57.1 100.0 18.3 July 72.3 86.0 58.4 100.0 23.6 August 73.6 86.7 60.1 100.0 22.9 September 71.2 85.3 57.2 100.0 19.9 October 67.4 82.7 52.6 100.0 17.9 November 67.0 80.7 53.0 100.0 16.1 December 68.6 82.6 54.7 100.0 22.8 1/1/74 - 12/31/00 69.6 84.3 54.7 100.0 14.1 06/28/18 2.3-54 Rev. 31

E. Episodes of Ambient Temperature Below 0.0°F:

Date(s) Time(s) Minimum (°F) Duration (hrs)

January 23, 1976 0300-0915 -2.0 6.50 January 18, 1977 0630-0800 -0.2 1.75 February 11, 1979 0315-0915 -2.7 6.25 February 12, 1979 0245-0315 -0.2 0.75 February 12, 1979 0345-0815 -1.5 4.75 February 14, 1979 0330-0830 -2.7 5.25 February 17, 1979 0700 -0.0 0.25 February 18, 1979 0230-0815 -2.0 6.00 December 25, 1980 0700-1400 -5.1 7.25 December 25-26, 1980 1645-0300 -1.8 10.50 January 5, 1981 0230-0300 -0.2 0.75 January 12, 1981 0445-0515 -0.0 0.75 January 12, 1981 0630-0800 -0.6 1.75 January 12, 1982 0800 -0.0 0.25 January 17-18, 1982 2215-0915 -2.9 11.25 January 22, 1984 0645 -0.0 0.25 January 22, 1984 0730 -0.4 0.25 January 16, 1994 0630-0930 -1.5 3.25 06/28/18 2.3-55 Rev. 31

E. Episodes of Ambient Temperature Below 0.0°F:

Date(s) Time(s) Minimum (°F) Duration (hrs)

January 19, 1994 0545-0815 -0.6 2.75 January 27, 1994 0345-0515 -0.2 1.75 January 16, 1994 0545-0730 -0.6 2.00 06/28/18 2.3-56 Rev. 31

F. Episodes of Ambient Temperature Above 86.0°F:

Date(s) Time(s) Maximum (°F) Duration (hrs)

July 18, 1977 1515-1800 87.6 3.00 July 7, 1981 1645-1830 88.7 2.00 June 24, 1983 1630-1700 86.9 0.75 July 16, 1983 1500-1615 88.7 1.50 July 16, 1983 1900 86.7 0.25 July 16, 1983 1945 86.5 0.25 August 20, 1983 1645-1845 89.4 2.25 July 12, 1984 1215-1515 91.0 3.25 July 24, 1984 1600-1830 88.2 2.75 August 8, 1984 1030-1230 90.0 2.25 August 17, 1984 1130-1730 88.3 6.25 August 31, 1984 1430-1730 89.6 3.25 August 18, 1987 1045-1245 87.6 2.25 July 23, 1989 1445 86.2 0.25 July 5, 1990 1245-1530 88.2 3.00 June 29, 1991 1145-1330 88.2 2.00 July 21, 1991 1800-1815 88.3 0.50 July 10, 1993 1615-1630 88.2 0.50 06/28/18 2.3-57 Rev. 31

F. Episodes of Ambient Temperature Above 86.0°F:

Date(s) Time(s) Maximum (°F) Duration (hrs)

July 10, 1993 1715-1745 86.7 0.75 June 19, 1994 1445-1715 89.2 2.75 July 15, 1995 1815-2030 88.5 2.50 July 30, 1995 1600-1745 87.3 2.00 July 22, 1998 1500 86.7 0.25 06/28/18 2.3-58 Rev. 31

BLE 2.3-20 COMPARISON OF MONTHLY AND ANNUAL AVERAGE DRY-BULB AND DEWPOINT TEMPERATURE AVERAGES AT BRIDGEPORT, CONN. AND MILLSTONE CLICK HERE TO SEE TABLE 2.3-20 28/18 2.3-59 Rev. 31

BLE 2.3-21 COMPARISON OF MONTHLY AND ANNUAL AVERAGE RELATIVE HUMIDITY AVERAGES AT BRIDGEPORT AND MILLSTONE CLICK HERE TO SEE TABLE 2.3-21 28/18 2.3-60 Rev. 31

ABLE 2.3-22 MEAN NUMBER OF DAYS WITH HEAVY FOG AT BRIDGEPORT, CONN. AND BLOCK ISLAND, RHODE ISLAND (1951-1981)

CLICK HERE TO SEE TABLE 2.3-22 28/18 2.3-61 Rev. 31

TABLE 2.3-23 WIND DIRECTION/STABILITY CLASS/VISIBILITY JOINT FREQUENCY DISTRIBUTION AT MILLSTONE CLICK HERE TO SEE TABLE 2.3-23 28/18 2.3-62 Rev. 31

ABLE 2.3-24 PERSISTENCE OF POOR VISIBILITY ( 1 MILE) CONDITIONS AT MILLSTONE (HOURS) (1974-1981)

CLICK HERE TO SEE TABLE 2.3-24 28/18 2.3-63 Rev. 31

BLE 2.3-25 BRIDGEPORT PASQUILL STABILITY CLASS DISTRIBUTION (1949-1980)

CLICK HERE TO SEE TABLE 2.3-25 28/18 2.3-64 Rev. 31

ABLE 2.3-26 MILLSTONE STABILITY CLASS DISTRIBUTION USING DELTA-T FOR STABILITY DETERMINATION CLICK HERE TO SEE TABLE 2.3-26 28/18 2.3-65 Rev. 31

ABLE 2.3-27 MILLSTONE STABILITY CLASS DISTRIBUTION USING SIGMA THETA FOR STABILITY DETERMINATION CLICK HERE TO SEE TABLE 2.3-27 28/18 2.3-66 Rev. 31

BLE 2.3-28 COMPARISON OF PASQUILL STABILITY CLASS DISTRIBUTION AT BRIDGEPORT, CONN. AND MILLSTONE CLICK HERE TO SEE TABLE 2.3-28 28/18 2.3-67 Rev. 31

BLE 2.3-29 PERSISTENCE OF STABLE CONDITIONS (E, F, AND G STABILITIES)

AT MILLSTONE (1974-1981)

CLICK HERE TO SEE TABLE 2.3-29 28/18 2.3-68 Rev. 31

ABLE 2.3-30 SEASONAL AND ANNUAL ATMOSPHERIC MIXING DEPTHS AT MILLSTONE CLICK HERE TO SEE TABLE 2.3-30 28/18 2.3-69 Rev. 31

TABLE 2.3-31 ON-SITE METEOROLOGICAL TOWER MEASUREMENTS PRIMARY METEOROLOGICAL TOWER Elevation (above base) *

(ft) (m) Measurements 447 136.3 Wind Speed and Variance Wind Direction and Variance Air Temperature Temperature Difference to 10 m Level 374 114.0 Wind Speed and Variance Wind Direction and Variance Temperature Difference to 10 m Level 142 43.3 Wind Speed and Variance Wind Direction and Variance Temperature Difference to 10 m Level 64 19.5 Air Temperature 33 10.0 Wind Speed and Variance Wind Direction and Variance Air Temperature Humidity 5 1.5 Solar Radiation **

BACKUP METEOROLOGICAL MAST Elevation (above base) ***

(ft) (m) Measurements 33 10.0 Wind Speed and Variance Wind Direction and Variance Base of tower at 15 ft msl Mounted on a platform to south of tower Base of mast at 73 ft msl 28/18 2.3-70 Rev. 31

ABLE 2.3-32 MILLSTONE METEOROLOGICAL TOWER INSTRUMENTATION Parameter Sensor Model nd Speed Climatronics F460 nd Direction Climatronics F460 mperature Climatronics 100093 mperature Difference Climatronics 100093 midity Climatronics 100098 lar Radiation Eppley 848 28/18 2.3-71 Rev. 31

TABLE 2.3-33 MONTHLY

SUMMARY

OF DATA RECOVERY RATES/

METEOROLOGICAL SYSTEM CLICK HERE TO SEE TABLE 2.3-33 28/18 2.3-72 Rev. 31

UNIT 3 UNIT 3 VENT MILLSTONE MILLSTONE STAC DOWNWIND CONTAINMENT TO MILLSTONE UNIT 3 VENT TO TO NEAREST STACK TO TO NEAREST SECTOR EAB STACK TO EAB NEAREST LAND RESIDENCE LAND RESIDENCE SSW 524 (2) 496 (2) 14,500 14,500 14,500 14,500 SW 524 (2) 496 (2) 3380 3380 3660 3820 WSW 524 (2) 496 (2) 3050 3050 3270 3290 W 524 (2) 496 (2) 2700 2700 3050 3070 WNW 524 (2) 649 2310 2310 2700 2760 NW 524 (2) 710 680 680 947 997 NNW 532 1029 690 690 1029 1029 N 782 1677 920 920 1695 1695 NNE 826 813 1550 1550 813 813 NE 548 496 (1) 840 840 496 736 ENE 524 (1) 496 (2) 600 810 1101 1560 E 524 (2) 496 (2) 1300 1300 1410 1480 ESE 524 (2) 496 (2) 1690 1690 1640 1760 SE 524 (2) 496 (2) 31,700 31,700 31,700 31,700 SSE 524 (2) 496 (2) 12,390 12,390 12,390 12,390 S 524 (2) 496 (2) 13,100 13,100 13,100 13,100 (1) Shortest Exclusion Area Boundary Distance in any Landward Sector (2) Water Sector, SO(1) is used when greater than shoreline distance 06/28/18 2.3-73 Rev. 31

06/28/18 2.3-74 Rev. 31 06/28/18 2.3-75 Rev. 31 06/28/18 2.3-76 Rev. 31 06/28/18 2.3-77 Rev. 31 06/28/18 2.3-78 Rev. 31 06/28/18 2.3-79 Rev. 31 06/28/18 2.3-80 Rev. 31 06/28/18 2.3-81 Rev. 31 06/28/18 2.3-82 Rev. 31 06/28/18 2.3-83 Rev. 31 information given here is sufficient for making an independent hydrological engineering ew of hydrologically related design bases, performance requirements, and bases for operation structures, systems, and components important to safety. It considers the hydrological nomena and conditions associated with the site. It also gives the flooding protection uirements and the emergency operation requirements.

1 HYDROLOGIC DESCRIPTION s section describes the site and all safety related elevations, structures, exterior accesses, ipment, and systems from the standpoint of hydrologic considerations.

1.1 Site and Facilities lstone Point is located on the north shore of Long Island Sound. To the west of the site is ntic Bay and to the east is Jordon Cove. Figure 2.4-1 shows the topography of the site, and ure 2.3-1 shows the general topography of the Millstone area. As discussed in Section 2.4.5, large radius, slow forward speed of translation, probable maximum hurricane (RL/ST PMH) used to calculate the maximum still water level, or surge, and the design basis flood level ximum combination of storm surge and wave runup). All safety related unit structures and ipment, except the circulating and service water pump house, are protected from flooding due torm surge by the site grade of elevation +24 feet msl. Flood protection of the pump house and er safety related structures and facilities from hydrologically or hydrometeorologically uced flooding is discussed in Section 3.4.1.

1.2 Hydrosphere public water supplies within a 20 mile radius of the site are identified on Figure 2.4-2. The ace and groundwater supplies within a 20 mile radius are identified and their characteristics listed in Table 2.4-1. This information was furnished by the Water Supplies Section, Bureau Health Promotion and Disease Prevention of the Connecticut State Health Department. The rest surface water supply is the New London Water Company's Lake Konomac, 6 miles north-hwest of the site. No surface drainage from the site could affect these reservoirs due to the ance involved, the topography, the expected groundwater gradient between the reservoir areas the site, and the generally impervious nature of the overburden on and near the site.

bedrock surface outcrops at the south end of Millstone Point and is generally covered with a r of dense glacial till towards the north end. Groundwater flows across the site through the vious outwash sands in a northeast-southwest direction towards Long Island Sound at roximately a 2-percent gradient, as shown on Figure 2.5.4-37. Some surface water collects in ressions in the marshy areas north of the site.

tion 2.4.13 describes the groundwater hydrology in the vicinity of the site.

28/18 2.4-1 Rev. 31

thern portion of Millstone Point is protected from wave action by concrete seawalls adjacent he intake structures of the three Millstone units.

mal tides at Millstone Point are semidiurnal with a mean range of 2.7 feet and a spring range

.2 feet. Tides in excess of the mean high water occur on an average as follows: in excess of 3 about once a year, in excess of 2 feet about 5 times a year, and in excess of 1 foot about 98 es a year. Mean high water (mhw) at Millstone Point is 1.3 feet msl. Mean low water (mlw) is feet msl.

al current measurements were made at various locations in the vicinity of Millstone Point, by Essex Marine Research Laboratory in 1965, and by the U. S. Coast and Geodetic Survey C&GS, now NOAA) in August and September of 1965. Figure 2.4-3 shows the location of survey stations.

results of the Essex Marine Laboratory tidal current survey (Figure 2.4-4), taken at the index ion indicate an asymmetry between the flood and ebb tides, with the flood tide achieving a k velocity of 1.75 fps and the ebb tide reaching a peak velocity of 1.48 fps. The USC&GS 5 data are generally consistent with the data collected by the Essex Marine Laboratory.

tom profiles (Figure 2.4-5) were run by Essex Marine Laboratory from Station 1 through ion 2 to the shoreline, and from Station 4 to Station 3 to the shoreline, with a continuous rding fathometer. Using a mean velocity of 0.857 fps for the tidal cycle beginning 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> ore low slack water on September 2, 1965 (obtained from the current survey) calculations w a mean tidal flow of 126,287 cfs in the Twotree Island Channel, and 79,186 cfs across the ion running from Station 4 northeast toward the shore.

2 FLOODS s section reviews the flood history in the vicinity of Millstone Point, flood design siderations, and the effects of local intense precipitation.

2.1 Flood History only sources of flooding that could affect Millstone 3 are direct rainfall and storm surge.

tion 2.3.1 discusses historical rainstorms. Historical hurricanes and the resulting surges are cribed in this section.

ce Millstone Point is a peninsula projecting into Long Island Sound, it is subjected to tidal ding from severe storms. The highest such flooding has resulted from the passage of icanes. The literature (NOAA 1968, U.S. Army Corps of Engineers 1965, Harris 1963, and field et al., 1957) indicates that twelve severe hurricanes have crossed coastal southern New land since 1635 and that four of these storms occurred in the past 40 years.

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ls recorded in the vicinity of Millstone Point.

Storm Center Flood Tide Date of Distance from Flood Tide Levels Hurricane Inland Crossing Millstone Point (msl in feet) 1/38 15 miles east of New Haven 20 miles west 9.7 4/44 Between Charlestown, RI, 35 miles east 6.2 and Pt. Judith, RI 1/54 Vicinity of Millstone Point Within vicinity 8.9 2/60 Vicinity of Millstone Point Within vicinity 6.0 ure 2.4-6 is a frequency plot of tidal flooding at New London, Connecticut, about 10 miles of Millstone Point. This figure was based on information presented in Plate 1-6 of the U.S.

y Corps of Engineers report (1965). The plot is based on 25.5 years of records (July 1938 -

ember 1963) at a recording tide gage located at the State Pier in New London since July 1938 149 year record (1815- 1963) of high water marks. The continuous tide record was used to ne the lower end of the frequency curve, and the record of high water marks was used to blish the upper portion of the curve. Because of the proximity of Millstone Point to New don and because of the similar exposure of the two areas to tidal flooding, the frequency plot epresentative of Millstone Point tidal flood frequencies. This plot indicates that the 9.7-foot l recorded during the 1938 hurricane would have a recurrence interval of about 335 years and 8.9-foot level reached in 1954 would have a recurrence interval of about 100 years.

2.2 Flood Design Considerations controlling event for flooding at the Millstone site is a storm surge resulting from the urrence of a probable maximum hurricane (Section 2.4.5). As discussed in Section 2.4.5, the imum still water level is +19.7 feet msl, and the associated wave runup elevation is +23.8 feet

. All safety related unit structures and equipment, except the circulating and service water phouse, are protected from flooding due to storm surge by the site grade elevation for Unit 3 24.0 feet msl. The service water pumps and motors are located at elevation +14.5 feet msl de watertight cubicles of the pumphouse. The walls of the cubicles are watertight to elevation

.5 feet msl, protecting the pump motor control centers and associated electrical equipment m flooding due to wave action and storm surge. The front wall of the intake structure extends levation +43.0 feet msl; it is designed to withstand the forces of a standing wave or clapotis h a crest elevation of +41.2 feet msl. Section 3.4.1 gives further flood design considerations on m surge and wave action.

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1. The design basis flood levels comply with Regulatory Guide 1.59, Revision 2, Positions C.1.b, C.1.e, and C.4.

2. Regulatory Guide 1.59, Revision 2, Positions C.1.a, C.1.c, C.1.d, C.2.a, C.2.b, C.2.c, C.2.d, and C.3 are not applicable.

er to Section 1.8 for clarification to Position C.1.

commitments for compliance are made or implied for the to be issued appendices.

2.3 Effect of Local Intense Precipitation rometeorological Report No. 33 (U.S. Weather Bureau 1956) was used to develop the design s probable maximum precipitation (PMP) for the site. In addition, the most recent PMP dance available on rainfall depth-duration relations, Hydrometeorological Reports No. 51 hreiner 1978) and No. 52 (Hansen 1982), collectively referred to as HMR-51/52, was used to rmined the impact of this ultra- conservative PMP-induced site flooding on plant safety-ted structures.

all season envelope PMP for the site based on HMR-51/52 is tabulated below. PMP values durations of 5 to 15 minutes for drainage basins of less than 1 square mile are applicable to the lstone site.

Probable Maximum Precipitation Hydromet Duration Rainfall Depth for 1 mi2 Area (inches) Report Number 5 min 5.86 52 15 min 9.22 52 30 min 13.2 52 1 hr 17.4 52 6 hr 26.0 51 storm drains are designed to pass, without flooding, a rainfall intensity of 6.5 iph for an mited duration.

tudy was performed to determine the impact of the HMR-51/52 PMP intensity on the roof.

f area and ponding level due to PMP for Category I structures are presented in Table 2.4-12.

ults of the study show that roofs of safety related structures are capable of withstanding loads to accumulation of rainwater (see Table 2.4-9). Scuppers are provided in parapet walls of the trol, hydrogen recombiner, and containment enclosure buildings to preclude the possibility of 28/18 2.4-4 Rev. 31

therproof and are located above the level of maximum ponding on the roofs.

ers of equipment removal hatches are located on curbs which are higher than the roof parapet ls with the exception of the hydrogen recombiner building, control building, and the ulating and service water pumphouse. The hydrogen recombiner building hatch is flush with roof slab. The entire roof is covered with a waterproof sheet membrane. The membrane is ered with a 6 inch thick reinforced concrete wearing slab. No leakage is anticipated. The ke pumphouse and control building hatch cover seals remain structurally intact under rostatic loading, which is not capable of overcoming the dead weight of the concrete hatch ers acting on the seals. Details for sealing of the hatch covers are provided on Figures 2.4-35, 36, and 2.4-37.

overflow lengths of the parapet wall on the roof used in PMP analysis for Category I ctures are presented in Table 2.4-13.

as estimated that the seal of the hatch cover on the control building roof would be under a imum depth of 3 inches of water for a short duration, during the peak roof ponding due to a P event. To make the seal watertight, a continuous 0.5 inch thick by 4 inch neoprene pad is ented to the sill angle, which is embedded along the perimeter of the hatch cover curb. The inch thickness envelopes the permitted tolerance in the construction of the hatch cover and the b.

ground elevation surrounding all buildings is elevation 24.0 feet msl with all safety related ding entrances and ground level floors set at elevation 24.5 feet except the Demineralized er Storage Tank (DWST) Block House and Refueling Water Storage Tank (RWST)/SIL Valve losure. The entrance elevation for the DWST Block House is elevation 24.33 feet with ground l floor set at elevation 24.0 feet msl and the entrance and ground level floor for the RWST/SIL ve Enclosure are set at elevation 24.33 feet msl. The yard area north of the control building the waste disposal building is depressed below elevation 24.0 feet to create a swale to drain PMP flood flow. The site was considered to be rendered impermeable due to saturation prior he onset of the precipitation of highest intensity.

site was divided into drainage basins according to the revised topography and plant layout as wn on Figure 2.4-7. Runoff hydrographs were developed using the U.S. Army Corps of ineers HEC-1 flood hydrograph computer program. The surface area of buildings that were hin the drainage basins were included in the runoff calculations. The following two servative assumptions were made for this analysis: (1) no credit was taken for the site storm nage system, and (2) zero infiltration rate was assumed for the analysis. Data for the drainage ns, runoff coefficients, and computed flows are presented in Table 2.4-10.

difications were made to the grading plan at the site boundary to prevent water in Basins A B from flowing into Basins C and D where the safety related structures are located.

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waste disposal building. Basin C consists of the yard area north of Basin C as constricted by ting structures. Basin D consists of the yard area south of the containment building. Flood er from basin C flows west past the waste disposal building to the area north of the control ding, and then over the roadway to the west of the site. Water from Basin C has been servatively assumed to contribute totally to Basin C flows. Water from Basin D flows east ween the containment building and the railroad tracks, through the Unit 2 area and on to the rry southeast of the site.

computed flows were then used to determine the water surface profile for each basin by zing the latest version of the U.S. Army Corps of Engineers HEC-2 Computer Program ter Surface Profiles, Computer Program 723-X6-L202A). The swales and depressions that m drainage channels were divided into reaches to construct the model. Cross sections were n to accurately describe the channel, site topography, and project features such as road crowns railroad tracks. The locations of the cross sections are shown on Figure 2.4-7. Conservative es for Manning's coefficient were chosen as follows: lawn areas 0.05, paved areas 0.015, bination paved and gravel areas 0.020 and gravel covered areas 0.025. PMP runoff was portioned into local incremental flows and then introduced at the appropriate cross sections.

computed water surface elevations at the safety related structures are summarized in le 2.4-11. In Drainage Basin C, the computed water surface elevation exceeds the door sill ation of 24.5 feet at the auxiliary building. In Drainage Basin D, the computed water surface ation exceeds the door sill elevation of 24.5 feet at the main steam valve, auxiliary, ineered safety features, fuel and hydrogen recombiner buildings. A detailed analysis sidering the effects of doors A-24-5 and A-24-6 in Drainage Basin D show that the water will exceed elevation 25 feet inside door A-24-5. A ramp and curb are installed inside auxiliary ding door A-24-5. The curb has a top elevation of 25.0 feet to keep runoff from Drainage in D from entering the auxiliary building.

ults of a detailed analysis of the hydrogen recombiner and main steam valve buildings showed the depth of any potential inleakage would be on the order of 0.16 feet which is substantially than the base of any safety related equipment. Detailed analysis of the engineered safety ures building showed that the depth of any potential inleakage would be in the order of 0.44 in the worst location which is substantially less than the base of any safety related equipment.

ailed analysis of the auxiliary building in Drainage Basin C and the fuel building in Drainage in D showed that any potential inleakage would be insignificant and would not affect any ty related equipment.

rainage Basin D, the computed water surface elevation 24.85 feet exceeds the entrance floor ation of 24.33 feet at the DWST Block House and the RWST/SIL Valve Enclosure. The worst mergence level of 24.85 feet would not affect any safety related equipment in the DWST ck House and RWST/SIL Valve Enclosure.

vice building exterior door may allow a small amount of inleakage into the service building.

s water may leak into the auxiliary building or control building. The total inleakage into the 28/18 2.4-6 Rev. 31

tified in Section 3.11.

ce the intensity of winter PMP is only about half of the annual PMP (U.S. Weather Bureau

6) and the snow accumulation on the road is plowed regularly, flooding at the site is not cipated in the winter.

3 PROBABLE MAXIMUM FLOOD ON STREAMS AND RIVERS re are no major rivers or streams in the vicinity of Millstone Point, nor are there any ercourses on the site. A number of small brooks flow into Jordan Cove, east of the site, and the Niantic River and thence to Niantic Bay, west of the site. Any flooding of these brooks, n as a result of the probable maximum precipitation, would not significantly raise the water ls in Niantic Bay, Jordan Cove, or Long Island Sound in the vicinity of the site. Additionally, ach area, local topography precludes flooding of any portion of the site from the landward 4 POTENTIAL DAM FAILURES, SEISMICALLY INDUCED ce there are no major rivers or streams in the vicinity of Millstone Point, the effects of ential dam failures, seismically induced, are not applicable.

5 PROBABLE MAXIMUM SURGE AND SEICHE FLOODING 5.1 Probable Maximum Winds and Associated Meteorological Parameters meteorological characteristics used to calculate the probable maximum storm surge at the lstone Point site are those associated with the PMH as reported by the U.S. National Oceanic Atmospheric Administration (NOAA) in their unpublished report HUR 7-97 (NOAA 1968).

R 7-97 describes the PMH as ...a hypothetical hurricane having that combination of racteristics which will make it the most severe that can probably occur in the particular region olved. The hurricane should approach the point under study along a critical path and at an mum rate of movement. The hurricane characteristics used in establishing the PMH include:

1. Central Pressure Index (CPI) - the minimum surface pressure in the eye of the hurricane

2. Radius of Maximum Wind (R) - the distance from the eye of the hurricane to the locus of maximum wind

3. Forward Speed (T) - the rate of forward movement of the hurricane center (eye)

4. Maximum Gradient Wind (Vgx) - the absolute highest wind speed in the belt of maximum winds 28/18 2.4-7 Rev. 31

where hurricane circulation ends R 7-97 presents values for each of those characteristics for each degree of north latitude along East Coast United States. Single values are presented for CPI and P and three values are given both R and T. Since Vgx is dependent upon Pn, CPI, and R, three values are also given for this meter. At the Millstone Point latitude (approximately 41 degrees north) the following PMH racteristics are recommended in HUR 7-97 (NOAA 1968).

1. CPI: 27.26 in Hg

2. R for small radius storm (RS): 8 nmi R for medium radius storm (RM): 24 nmi R for large radius storm (RL): 48 nmi

3. T for slow forward speed (ST): 15 knots T for high forward speed (HT): 51 knots T for high forward speed (HT): 51 knots

4. Vgx for RS: 131 mph (114 knots)

Vgx for RM: 128 mph (111 knots)

Vgx for RL: 124 mph (108 knots)

5. P: 30.56 in Hg PMH maximum gradient wind speeds are used for surge analysis only, design wind loads for ctures can be found in Section 3.3.1.

5.2 Surge and Seiche Water Levels hough frontal storms and squall lines cause tidal flooding in the Millstone Point area, by far the t severe flooding has resulted from hurricanes. For this reason, the PMH as defined in HUR 7 (NOAA 1968) was used to compute the design storm surge level at the site. The calculated l surge height or still water level includes the wind setup, the water level rise due to ometric pressure drop, the astronomical tide and forerunner or initial rise.

culation of the total surge height used a computerized bathystrophic storm surge model, which ased on procedures described in Freeman et al. (1957), Bodine (1971), Bretschneider et al.

63), and Marinos et al. (1968). This theory was derived from the momentum and continuity ations with basic physical assumptions (Freeman et al., 1957, Bodine 1971). The model has n used to predict hurricane surge with good agreement with observed data (Bretschneider et 1963, Marinos et al., 1968). Use of this model requires that the storm be brought ashore from 28/18 2.4-8 Rev. 31

ves onshore. In determining the maximum surge at Millstone Point, the locus of maximum ds is brought inshore along a track which passes just to the east of the eastern end of Long nd. This track produces the maximum surge heights at the mouth of Long Island Sound and sequently at Millstone Point.

of the bathystrophic storm surge program requires the input of several meteorological and sical parameters, including: the central pressure, the peripheral pressure, the maximum wind ed, the radius to maximum wind, the speed of translation, the initial rise, the astronomical tide, bottom profile along the track of the maximum winds, the bottom friction coefficient, and the pe of the curve describing the relationship between the ratio of wind speed at any point to imum surface wind speed and the ratio of the radius at any point to the radius to maximum

d. In addition, provision is made to enter a wind stress correction factor.

eneral, the maximum surge and maximum wave need not be coincidental. For this reason, e, wave heights, and corresponding runup at different times were considered. The maximum bination of the surge and runup on various plant structures were considered as the most severe d level for the site.

morandum HUR 7-97 (NOAA 1968) gives three different values for both radius to maximum d and speed of translation; therefore, it was necessary to compute nine different surge levels g all of the possible combinations of meteorological parameters. These calculations indicated the large radius (RL) slow speed of translation (ST) storm yields the highest surge level at lstone Point. The input parameters for this storm are as follows:

Central pressure 27.26 inches Hg Peripheral pressure 30.56 inches Hg Maximum gradient wind 124 mph (108 knots)

Radius to maximum wind 48 nmi Speed of translation 15 knots Astronomical tide (10 percent exceedance high tide) 2.4 feet above msl Initial rise (Regulatory Guide 1.59, Table C.1) 1.0 feet Bottom friction 0.0025 Wind stress coefficient factor 1.10 Bottom profile (Figure 2.4-8)

Hurricane track (Figure 2.4-12) ge analyses based on different types of hurricanes show that the large radius, slow forward ed hurricane produces the maximum stillwater level at the Millstone site.

28/18 2.4-9 Rev. 31

5.3 Wave Action ve characteristics are dependent upon wind speed and duration, wind direction, fetch length, water depth. Millstone Point is sheltered from the direct onslaught of open ocean waves by g Island. Moreover, the unit itself is located on the western side of the Point and a siderable distance (about 2500 feet) inland from the southernmost tip. Thus, the topography of Point itself protects the unit area from breaking waves during the period of peak tidal flooding n the winds are from the southeast quadrant.

maximizing hurricane effects, the hurricane track was bent in order to have the maximum d attack the site for the maximum possible time. The tracks are shown on Figures 2.4-12 ugh 2.4-14. Because of the location of the site, two possible methods of generating maximum es, deep- and shallow-water waves, were considered.

5.3.1 Deep Water Waves first method was to generate deep-water waves offshore of the continental shelf and let them pagate over the shelf to Block Island Sound, finally reaching the Millstone location. Two ependent analyses, one graphically by Wilson (1955, 1963) and the other computational by tschneider (1972) provide comparison for deep water waves.

Wilson Analysis ve forecasting in deep water depends on a number of empirical relationships involving the ables of significant wave height H, significant wave period T, wind velocity U, wind duration d length of the fetch F.

se relationships are as follows:

gH 1 gx 1/2 (2.4.1)

---

= 0.26 tan h --------- ------2 U

2 100 U c- = 1.40 tan h 4.36 gx 1/3 (2.4.2)

U 100 U 2 re:

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U = Wind velocity (fps) c = Deep water velocity of significant waves (fps) x = Finite fetch over deep water (ft) g = Acceleration due to gravity (ft/sec2) using Equations 2.4.1 and 2.4.2 and the fact that the group velocity of the wave is half of its e celerity, a H-t-F-T diagram covering the variables H, T, U, t, and F was constructed ording to Wilson's graphical method. A transect along the forward direction on the hurricane d field was then chosen, such that the wind components represent the maximum energy ilable for the wave generation. At this time, a space-time field of the wave generating wind ponent was constructed in conjunction with the hurricane forward velocity.

adjusting the space-time field in the t-F quadrant of the H-t-F-T diagram, different significant e heights and wave periods can be obtained for specific locations of the hurricane. This hod was applied to the RL ST, RL MT, and RL HT probable maximum hurricanes, with the lts given in Table 2.4-2. The low speed hurricane exhibited higher deep water waves than the ium or high speed hurricanes.

cial adaptation of the H-t-F-T diagram also gave information regarding time lags between e levels and wave heights. This was accomplished by determining distances from the icane eye to the actual wave and noting that the hurricane travels at its translational velocity the wave at its group velocity.

Bretschneider Analysis analysis by Bretschneider (1972) uses empirical data of 51 typical hurricanes to determine dimensional, stationary deep water wave field models. The maximum significant wave height to a stationary hurricane is as follows:

H R = k' RP (2.4.3) re:

28/18 2.4-11 Rev. 31

HR = Maximum significant wave height at R, stationary hurricane (ft)

R = Radius to maximum wind (nmi)

P = Central pressure reduction from normal (in Hg) a hurricane moving forward at a speed equal to or less than the critical forward speed (VCR =

exp RP/200), it can be shown that:

U 2 H R' = 1 + 2U

---

+ -------- H R (2.4.4)

UR UR U = 1/2 V cos (2.4.5) re:

HR = Maximum significant wave height (feet, corrected for forward speed of hurricane)

UR = Maximum wind speed (knots)

V = Forward speed of hurricane (knots)

= Angle position of the radius measured counter-clockwise from its axis (degrees) was found that Bretschneider's estimate of hurricane waves produced by slow moving icanes was in agreement with the graphical solution of Wilson (Table 2.4-2). Bretschneider provided formulation for calculating the critical wave speed. The medium and high-speed icanes were found to have forward speeds higher than the critical speed computed. Since tschneider's method included assumptions applying only to the slow moving storms, no parison was possible with the waves generated by medium and high speed storms.

5.3.2 Shallow Water Waves second method considers shallow water wave generation. The geographic characteristics of g Island Sound prevent deep-water waves from propagating through Long Island Sound.

wever, as hurricanes follow the track, moving over Long Island Sound and turning north-ward as shown on Figures 2.4-12 through 2.4-14, wind generates waves within the Sound. As ave grows in height and length, the attenuation of energy by bottom friction begins to hinder rowth. The wave attack on site thus depends on the complex interaction of shoaling, bottom tion, refraction, wind duration, and available fetch.

rgy loss due to bottom friction has been studied by Putnam and Johnson (1949), Bretschneider Reid (1954), and Bretschneider (1954a). Combining the deep-water wave relationship given Wilson (1963) and the shoaling and energy dissipation by friction Putnam and Johnson (1949),

28/18 2.4-12 Rev. 31

tschneider's method (1954b) is extensively used in this study with a conservative friction fficient of 0.01 as suggested by the U.S. Army Corps of Engineers, Shore Protection Manual 77). However, instead of using a constant wind, a variable wind for generating the wave was n to be the wind component along the specific direction of the hurricane.

ual bottom topography along the specific direction was also used. The location and bottom ography of the three transects considered for Long Island Sound are shown on Figure 2.4-15.

ve heights generated by the slow, medium, and high speed PMH are shown in Tables 2.4-3 ugh 2.4-5.

5.3.3 Wave Shoaling nges in deep-water waves occur as they cross the continental shelf into intermediate water ths. The effects which must be included are the combined effects of bottom friction, the tinued action of the wind, and the forward speed of the hurricane. All of these effects were n into account by a computer program following the method developed by Harrison and son (1964).

above method also makes use of dissipation functions, introduced by Putnam and Johnson 49), which obtain the reduction factor due to friction for any bottom slope, depth, initial wave ht, or wave period. The continued action of the wind was taken into account by using tschneider's (1954a) determination of energy added to wind stress. The results of wave height uction due to shoaling, with dissipation functions included, are shown in Table 2.4-2.

5.3.4 Wave Refraction process of refraction causes water waves to change direction when going from deep water to low water, because the inshore portion of the wave front travels at a lower velocity than does portion in deep water. It is this change in orthogonal directions which causes the wave heights e either magnified or reduced.

rogram by Harrison and Wilson (1964) was adopted for the wave refraction study.

h the depth information on the constructed grid layout and the incident wave period and angle, program constructed the wave rays inside the grid layout. In each ray construction step, a ar interpolation from wave celerities at four adjacent grid points was used. Wave refraction considered to be significant for waves traveling through the Block Island Sound grid (along h shoaling) and the Millstone grid (Figure 2.4-16). The actual areas considered, along with action diagrams at various angles of approach, are shown on Figures 2.4-17 through 2.4-21.

resulting wave heights after shoaling and refraction are shown in Table 2.4-2.

28/18 2.4-13 Rev. 31

wave data at three critical transects (Figures 2.4-22 through 2.4-25) was used to compute the ation of maximum wave runup. Saville's method of composite slopes (U.S. Army Corps of ineers 1977) was used, which relies on laboratory data to form curves relating the runup to e steepness, structure type, and the depth at the structure toe. In order to obtain a maximum up, the method of composite slopes was applied to several wave periods within the permissible ge along with several controlling depths. The maximum runup for transects B and C, which urs during the slow speed PMH, was calculated to be +23.8 feet msl and +21.2 feet msl, ectively.

5.3.6 Clapotis on Intake Structure water depth at the intake structure and the characteristics of the incident waves determine t type of waves would be formed at the intake, i.e., nonbreaking, breaking, or broken waves.

ailed analysis of incident waves showed only nonbreaking and broken waves are possible at intake of Millstone 3. The bottom profile leading to the intake structure is shown on ure 2.4-23.

ng the Miche-Rundgren (U. S. Army Corps of Engineers 1977) method, the maximum water l on the intake structure was calculated to be +41.2 feet msl. The maximum high water urred for the slow speed PMH at the time of the peak surge of +19.7 feet msl and a wave ht of 16.2 feet. Using this information, the maximum wave loading on the front of the intake cture was calculated and is shown on Figure 2.4-26.

5.4 Resonance onance phenomena in a water body excited by incident waves from the open sea are ciated with one or more of that body's natural periods. These natural periods vary with the

, shape, and depth of the water body. The extent of amplification at resonant period decreases h an increase in the order of harmonics considered. Therefore, in a resonant study, only the few lower harmonics are of concern.

the Millstone Point quarry in particular, neither the storm surge nor the waves associated with MH would cause the type of wave oscillations that are common in some harbors. The storm e is a long wave whose period is far greater than the natural period of the quarry which is mated to be about 1 minute. The net effect of the surge is to cause the water level in the quarry ary slowly in accordance with the water level variations in the immediately adjacent areas of g Island Sound.

ing the peak surge period, general flooding of the Millstone Point area causes the quarry to ome part of the open sea where resonance is not of concern. At a lower surge level, both before after the peak surge period, the quarry is connected to Long Island Sound by the discharge nnel which would allow waves to be transmitted in the quarry. However, because the incoming e period would be in the order of 10 seconds, about one-sixth of the estimated natural period g the long axis of the quarry, there would be no significant amplification of the waves 28/18 2.4-14 Rev. 31

pening the available wave energy.

ause the quarry is deep (about 100 feet), the wind fetch is short (about 1,400 feet), and there is utlet from the quarry to the Sound, there would be no natural period seiching in the quarry due ariable hurricane winds.

5.5 Protective Structures safety related structures and equipment, except the circulating and service water pumphouse, protected from flooding due to storm surge and wave action by the site grade elevation of +24 above msl. The effects of wave action on the pumphouse is the only topic discussed in this ion, flood protection of the pumphouse is discussed in Sections 2.4.1 and 3.4.1.

seaward wall of the intake structure is constructed of reinforced concrete designed to hstand the forces of a standing wave, or clapotis, with a maximum crest elevation of +41.2 feet

. The resultant hydrostatic pressure distribution on the intake wall is shown on Figure 2.4-26.

determine the maximum uplift pressure on the pumphouse floor, several combinations of surge l and coincident wave height for three different speed PMHs were examined. The maximum ft pressure on the watertight cubicles within the pumphouse was generated by the maximum e level of 19.7 feet msl and coincident wave height of 16.2 feet. The maximum net uplift sure on the pumphouse floor with openings was generated by a surge level at the same level he bottom of the pumphouse floor (11.5 feet msl) and a coincident wave height of 16.9 feet.

calculated maximum uplift pressure on the watertight cubicles is 863 psf. The calculated imum net uplift pressure on the pumphouse floor with openings is 557 psf. The pumphouse r, including the watertight cubicles, is designed to withstand pressure of more than 863 psf.

water level fluctuations within the pumphouse, resulting from storm surge and wave action, ld be dampened by the energy lost in passage through the restricted openings in the trash s, traveling screens, and operating deck. Internal water level fluctuations would be further nuated because water must enter the structure through a submerged opening (elevation -7 to feet) through which the pressure response factor would be less than unity.

ur protection for the service water lines located behind the pumphouse is provided by a crete retaining wall extending north from the west wall of the pumphouse.

reline protection in the vicinity of the pumphouse to prevent beach erosion is discussed in tion 2.5.5.1.

6 PROBABLE MAXIMUM TSUNAMI FLOODING areas of the North American continent most susceptible to tsunamis are those bordering the ific Ocean and the Gulf of Mexico. Millstone Point is located on the North Atlantic coastline 28/18 2.4-15 Rev. 31

7 ICE EFFECTS re is no history of ice in Niantic Bay or ice jam formation in the area of the circulating and ice water pumphouse. It is considered highly unlikely that ice would form or collect in a ner or amount sufficient to obstruct the flow to safety related pumps (Section 2.2.3).

einforced concrete curtain wall located at the front of the pumphouse and extending to -7.0 feet precludes floating or partially submerged ice from entering the pumphouse and damaging or cking the bar racks.

zil ice formation takes place in the presence of supercooling, where turbulence is too great to w surface ice to form, and can adhere to surfaces with a temperature equal to or less than the zing point of water. However, at velocities of less than 2 fps, submerged frazil ice rises to the ace and form sheet ice (Bureau of Reclamation 1974). Since the water velocity in the area of bar racks is approximately 1 fps, the possibility of submerged frazil ice adhering to the bar s is considered unlikely.

8 COOLING WATER CANALS AND RESERVOIRS re are no cooling water canals or reservoirs which would have any effect on safety related ipment.

9 CHANNEL DIVERSIONS re are no channel diversions to the cooling water supply which would have any effect on ty related equipment.

10 FLOODING PROTECTION REQUIREMENTS tion 3.4.1 discusses the flooding protection of safety related structures, and Section 2.4.2 gives tailed discussion of the design criteria for site and roof drainage facilities.

tion 2.4.13 states that there is one Technical Requirements Manual item and one plant cedure that describe the requirements for protection of safety related equipment and facilities to flooding.

11 LOW WATER CONSIDERATIONS 11.1 Low Flow in Rivers and Streams ce Millstone 3 does not depend on either rivers or streams as a source of cooling water, this ion is not applicable.

28/18 2.4-16 Rev. 31

bable minimum low water level at the Millstone 3 intake structure resulting from an urrence of a PMH oriented so as to cause maximum depression of the water surface (setdown) e site, is calculated to be -5.85 feet msl.

s estimate is based on a one-dimensional model with (U.S. Army Corp of Engineers 1977) h conservative assumptions regarding the hurricane track, wind field orientation, bottom ile, traverse line, and pressure effects. In addition, the model itself is inherently conservative ause it does not consider return flow along the sides of the negative surge axis.

large radius, slow speed of translation (LR/ST) PMH, with characteristics as specified in tion 2.4.5.1, is assumed to be the critical storm since the higher translational velocities of the h and medium speed of translation storms result in lesser offshore wind speeds on the ksides of those storms. The storm is assumed to approach along a track which is normal to the reline and which intersects the coast in western Rhode Island (Figure 2.4-27). The isovel ern of the LR/ST PMH is assumed to be the overwater isovel pattern, (Figure 2.4-28) lecting friction effects of overland traverse on the offshore part of the storm circulation. The d field at Millstone results from the advection of this isovel pattern along the specified track is shown on Figure 2.4-29. For the purpose of computing wind stress and resultant setdown, offshore wind directions considered to apply are from 315 degrees clockwise through 045 rees (with respect to true north). For the time period during which the winds are within this hore direction, the average offshore wind speed is 82 mph. This wind speed is assumed to be lied along the traverse line (axis) of an outward moving surge under steady state conditions re the water surface level is balanced by the wind stress. A constant wind direction parallel to surge traverse line is also assumed as a steady state condition.

surge traverse and bottom profile lines assumed for the model (Figure 2.4-27) are servative assumptions because the effects of Long Island are ignored and the surge is assumed e directed into the open ocean; that is, a traverse line inside Long Island Sound would not duce as much setdown because the length of available fetch would be much shorter and om friction effects more pronounced due to shallower water.

setdown at Millstone under the above assumptions was calculated for a wind speed of 82

h. Figure 2.4-30 shows a plot of calculated setdown versus wind speed for a range of wind eds from zero to 90 mph, added to the suggested 10-percent exceedence spring low tide level 0.75 feet mlw. At 82 mph the probable minimum low water level is calculated to be -4.45 feet or -5.85 feet msl.

design low water level of the service water pumps is -8.0 feet msl, compared to a servatively estimated -5.85 feet msl for probable minimum low water. Therefore, continuous ration of the service water pumps is ensured. The fire water pumps are supplied from two

,000 gallon storage tanks connected to the public water system of the Town of Waterford.

bable minimum low water has no effect on these pumps.

28/18 2.4-17 Rev. 31

torical low tides at New London, Connecticut, from 1938 to 1974 are given in Table 2.4-6.

minimum tide level recorded at New London was about -4.8 feet msl on December 11, 1943.

11.4 Future Control sideration of future control of the cooling water source is unnecessary since the plant uses er from Niantic Bay. The use of water from the Bay by future users would not affect the ling water supply because of the abundance of water available.

11.5 Plant Requirements ultimate heat sink consists of a single source of safety related cooling water, Long Island nd. Long Island Sound contains sufficient volume to provide cooling for extended time ods (greater than 30 days) to permit safe shutdown of the unit. The minimum safety related ling water flow required during accident conditions is provided in Table 9.2-1. Safety related t water requirements for all modes of operation are given in Table 9.2-1.

ing normal plant operation, cooling water is withdrawn from Long Island Sound and delivered wo of four available 15,000 gpm rated capacity service water pumps, enclosed in a Seismic egory I structure; the circulating and service water pumphouse (CSP). Figure 3.4-1 (sheets 3

4) shows the CSP (Section 3.4), configuration and minimum design operating water level.

h service water pump is designed to operate with a minimum submergence requirement of 4 11.6 Heat Sink Dependability Requirements ultimate heat sink for Millstone 3 is Long Island Sound. Sensible heat removed from both ty and non-safety related cooling systems during normal operation, shutdown, and accident ditions is discharged via the circulating and service water systems, through the quarry, and Long Island Sound. Both the circulating and service water systems have as their source of er Niantic Bay, which is fed from Long Island Sound. The ultimate heat sink (Section 9.2.5) sfies the requirements of Regulatory Guide 1.27.

g Island Sound is capable of dissipating waste heat under all environmental and operating ditions. Table 2.4-7 lists the heat loads rejected under various operating modes.

design low water level of elevation -8.0 feet msl for the service water pumps includes added servatism to the calculated extreme low water level of elevation -5.85 feet msl ction 2.4.11.2). The suction bells of the Millstone 3 circulating and service water pumps are ted at elevation -19.5 feet msl and elevation -13.0 feet msl, respectively; well below the low er levels. Therefore, during all operating conditions, sea water is available to the safety related ice water pumps. Table 9.2-1 gives the minimum cooling water flow required accident ditions for safety related service water loads. The circulating water system cooling water flow 28/18 2.4-18 Rev. 31

temperature extremes of the water in Niantic Bay and Long Island Sound are 80°F maximum 33°F minimum (see Section 9.2.1.1). Long Island Sound and Niantic Bay can provide a 30 supply of service water that does not exceed the design temperature, under any 30 day eorological conditions that result in maximum evaporation.

applicants have no knowledge of any history of significant ice formation in Niantic Bay. It is sidered highly unlikely that ice would form or collect in a manner or amount sufficient to truct the flow to the service water and circulating water pumps (Sections 2.4.7 and 2.2.3). A forced concrete curtain wall located at the front of the pumphouse and extending down to ation - 7.0 feet msl acts as an air seal and also prevents floating or partially submerged debris ice from entering the pumphouse. Additionally, the flow velocity at the bar racks is low ugh to cause frazil ice to rise to the surface and form sheet ice, such that there would not be kage affecting the service water pumps.

imentation that would affect the safety function of the service water pumps is considered kely. The suction bells of the circulating water pumps are at an elevation 6.5 feet lower than suction bells of the service water pumps. The rated flow capacity of the circulating water ps is approximately ten times larger than that of the service water pumps. Therefore, any ment that might settle in the pump bays downstream of the traveling screens would be oved by suction through the circulating water pumps before it could block the inlets to the ty related service water pumps. In the event that significant sedimentation should deposit on floor of the pumphouse bays, it would be removed by occasional dredging.

11.7 Dispersion, Dilution, and Travel Times of Accidental Releases of Liquid Effluents in Surface Waters persion characteristics and dilution capability of Niantic Bay and Long Island Sound for an dental release through the circulating water discharge tunnel is the only case discussed here.

tion 2.4.13 discusses the effects of contamination of groundwater, which subsequently flows Long Island Sound.

dictions of the dispersion and dilution of the accidental releases of liquid effluents in surface er are divided into two regions:

1. In the near-field, the dilution is due to momentum induced mixing and turbulence mixing created by the surface discharge jet from the quarry through the quarry cut into Long Island Sound.

2. In the far-field, the dilution is due to ambient tidal current in Niantic Bay and Long Island Sound.

assumed that no dilution occurred within the quarry. In the near-field at the edge of mixing e, the dilution factor was estimated to be 3 (E. E. Adams 1999). In the far-field dilution factors 28/18 2.4-19 Rev. 31

-dimensional equations of mass and momentum conservation:

ss:

- + ---- (2.4.6)

[ u ( h + ) ] + ----- [ v ( h + ) ] - = O t x y mentum:

u u u n 1 P a 1 (2.4.7)

---

+ u ----- + v ----- = - g ----- - --- --------- + fv + --------------------- ( w, x - b, x )

t x y x x ( h + )

---

v- + u ----v- + v ----v- = - g -----n - P a 1 (2.4.8)

- --------- + fu + --------------------- ( w, y - b, y )

t x y y y (h + )

re:

h = The wave height h = The mean water depth t = Time coordinate u and v = Velocity components in the x and y directions, respectively y = A source term which is defined as the discharge or intake rate per unit area at a specified grid point g = Gravitational constant Pa = Atmospheric pressure f = 2 sin = the Coriolis parameter hich:

= The angular velocity of the earth

= The latitude w and b = Shear stresses at the water surface and the bottom, respectively.

-2 2 2 b, x = gC u ( u + v )1/2 (2.4.9) 28/18 2.4-20 Rev. 31

re:

C = The Chezy coefficient ations 2.4.6 and 2.4.7 represent a two-dimensional transient hydrodynamic mathematical del in a general form. The source term is included because it would simulate the intake and harge flow effects on the ambient flow patterns. If the interested area is relatively small, Pa be assumed to be constant, and if there is no source or sink in the area ( = 0), then ations 2.4.6 and 2.4.7 are those shown in page 1.113-15 of Regulatory Guide 1.113.

numerical solution of Equations 2.4-6 through 2.4-8 was developed and a computer program written. In using the computer program, a collection of square cells, with the height equal to average water depth, is used to simulate Niantic Bay and the adjacent portion of Long Island nd. A grid size of 1,000 by 1,000 feet was used. Figure 2.4-31 illustrates the area modeled by cells. The solid line defines the closed boundary which was chosen to closely approximate the reline geometry from Black Point to Seaside Point. The dashed line defines the open boundary ch extends through the open water of Long Island Sound. The model boundary also includes Niantic River estuary.

model used tidal level information from the 1974 hydrographic hydrological survey as input btain flow pattern predictions (NUSCo. 1975). Current data from the same survey were used comparison and calibration. The bottom roughness (Manning's coefficient) was assumed to al one of three values (0.02, 0.03, or 0.045) depending on the bathymetric conditions and the city profiles obtained. A phase lag of 10.5 minutes was used across the model region (east to t). With these inputs and refinements, the model predicted the flow field and tidal heights hin the model region. A comparison of the predicted flow field velocities at points where ent meter measurements were available was performed (NUSCo. 1975). Reasonably good ement between current direction and magnitude existed between predicted and observed data.

output of the model indicates that during the strength of flood the flow pattern shows a eral westward circulation with maximum velocities of 2 fps in the Twotree Island Channel.

high slack stage occurs approximately 0.52 hour6.018519e-4 days <br />0.0144 hours <br />8.597884e-5 weeks <br />1.9786e-5 months <br /> after high tide. The flow pattern at this stage ws the low velocities and mixed directions characterizing this period of tide reversal. The tidal ent stage of the Niantic River estuary lags in time and still shows a moderate flooding current SCo. 1975).

strength of ebb develops about 4.05 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> after high tide and the flow pattern is from west to

. Finally, low slack water occurs and a general mixed flow pattern precedes a reversal ction. The tidal current stage of the Niantic River still lags the outer bay and shows an ebbing 28/18 2.4-21 Rev. 31

completely slack water conditions between the flood and ebb tides, a characteristic of rotary l current. Second, the time of lowest velocity does not always coincide with the high and low

, as is observed in other bays along open coastlines, but rather exhibits a lag of from 1/2 to 1 r usually (NUSCo. 1975).

resulting velocity field then becomes the advective mechanism in the following vertically raged conservation equation for the dissolved constituent concentration C (from Regulatory de 1.113):

--- ( HC ) + ----- ( uHC ) + ----- ( vHC ) =

t x y (2.4.11)

- C C

---

HK x ------ + ----- HK y ------ - HC x x y y re:

H = Depth from water surface to bottom Kx and Ky = Dispersion coefficients in the x and y directions, respectively l = Decay coefficient he numerical computation, an initial concentration Co is arbitrarily assigned as one of the ut data. The computer program computes the concentration, C(x,y), at every grid point in the rested area. The dilution factor, D, is given by:

Co D f = ----------------

- (2.4.12)

C ( x, y )

dispersion coefficients, kx, ky, used in the model described above were determined by using thermal plume survey data obtained in July 1977. In the process of calibrating the model for a

-unit operation, a sensitivity analysis shows that using a dispersion coefficient of 450 sq ft/sec h a limiting depth of 18 feet, the model yields results compatible with those from the dye ey (Liang and Tsai 1979).

cipal users of Niantic Bay or Long Island Sound waters in the vicinity of the plant are eational users. Table 2.4-8 summarizes areas of recreational water use and their esponding dilution factors. To be conservative, no travel time from the accidental release nt (quarry cut) to users was taken into consideration in calculating the concentrations of liquid taminants.

28/18 2.4-22 Rev. 31

ct this plant because of its distance from the site. No potential future users of Niantic Bay or g Island Sound water are known at this time.

12 GROUNDWATER 12.1 Description and Onsite Use undwater is not used as a source of plant water supply.

12.2 Sources Millstone site has several shallow wells near it, the nearest being about one-third of a mile m the station proper. None of these provides domestic drinking water, but one is used to water arby baseball field and to supply a drinking fountain at the field.

ee shallow wells (Figure 2.4-32) are located within 1.5 miles of the site; one nearly 1.5 miles he north-northeast, one approximately 1 mile to the northeast, the third approximately 0.5 mile he northwest.

ure 2.4-2 identifies the public water supplies within a 20 mile radius of the site.

undwater conditions on Millstone Point have been documented in previous studies for lstone 1 and 2, and have been observed by water level observations in borings drilled for the lstone 3 site study in 1972 (Section 2.5.4.6).

r to development of the site as a nuclear power facility, there existed a granite quarry located roximately 1,200 feet south- southeast of the Millstone 3 area. Observations of the water ls in the granite quarry show that the water level in the quarry before the existing discharge nnel opened it to the ocean, typically lay approximately 17 feet below the level of the adjacent g Island Sound. It is significant that this quarry was worked for over 100 years (1830-1960) at ances of as little as 200 feet from the waters of Long Island Sound without experiencing ble inflows of water indicating that the permeability of the bedrock is very low.

ssure tests (Table 2.5.4-16) were conducted in the vicinity of the quarry and in the tainment area as part of the Millstone 3 site study. These tests indicate that the bedrock is erally massive with slight to moderate interconnected jointing. Geologic mapping of the site rock indicated that the bedrock is fresh, hard crystalline rock with tight, moderately spaced ts. Very little inflow of water was noticed entering the excavations through the bedrock. These ervations also suggest that the permeability of the bedrock is very low, and that very little undwater or seawater seeps through the site bedrock.

h the basal till and the overlying ablation till are relatively impervious. The ablation till soils more pervious than the basal tills and occasionally exhibit partial stratification, including radic sand lenses; accordingly, the upper portions of the soil transmit water more readily than 28/18 2.4-23 Rev. 31

reline exhibited tidal fluctuations, suggesting that the occasional sand lenses can be quite meable (Bechtel 1972).

er levels measured in borings taken at the site in early 1972 indicate a groundwater ometric surface with a gradient generally sloping from northeast to southwest (Figure 2.5.4-alized perched groundwater conditions probably exist because of the irregular distribution of tion till materials of varying gradation and porosity. It is also likely that shallow, ponded er exists in localized bedrock troughs. The prevalence of bedrock outcrops to the north and hwest of the site indicate that bedrock acts as groundwater divide, isolating the soils of the tip Millstone Point from soils further inland.

ce there is no plant use of groundwater, and the plant area is isolated from soils further inland, e is no effect on groundwater on the site or surrounding areas.

undwater recharge would primarily be due to infiltration of local precipitation, with probable ration to the waters of the immediately-adjacent Long Island Sound. As previously described, e groundwater is present in the crystalline bedrock, and virtually all of the groundwater vement is restricted to the soil overburden. Measurements taken during previous investigations ldsmith 1960) showed average influx rates into test pits of about 8 gph and concluded that h the ablation and basal tills are relatively impervious.

12.3 Accident Effects hin a 5-mile radius of the Millstone 3 containment structure, public water supplies originate m ground sources, most of which are shallow wells and distant from the site. Three shallow ls shown on Figure 2.4-32 are located within 1.5 miles of the site. There are ridges in between Millstone 3 location and the wells which are undoubtedly underlaid by rock. They create a nage divide, the groundwater flowing to the east and west and to the south. Water or micals accidentally released during operation or accident conditions to the site surface would reach these wells. Accidental waste discharges would not affect public groundwater supplies e the Niantic River and Niantic Bay lie west and northwest of the site while accidental lage in the soil or rock column at the site while the Jordan Cove drainage basin is east of the

. Any accidental spillage in the soil or rock column at the site would be interrupted by these ies of water and would prevent contamination of distant groundwater sources. Elevations eeding those of the site and at-surface bedrock ridges preclude migration of contaminated undwater to the north.

investigation of possible diffusion in the groundwater was made, in case of an accidental id release of waste on the site outside the normal flow paths.

28/18 2.4-24 Rev. 31

estimated that 80 percent of tank volume (120,000 gal) liquid would be discharged into the und and eventually would reach the groundwater following the assumed tank failure. The tion of the boron recovery tank is such that the bedrock and basal till overlaying the rock h with very low permeability) have higher elevations to the south, east, and west of the tion. The rock contours to the northwest of the boron recovery tank indicate a depression sidered a channel through which the fluid might flow toward the trench for the circulating and ice water pipelines. The granular backfill to be used in this trench is estimated to have a her permeability than other surrounding soils (tills); hence, the trench offers the most probable for discharging the boron recovery tank liquid to Niantic Bay. Under these conditions, the th of the possible flow path (Figure 2.4-33) is approximately 1,230 feet.

e the boron recovery tank liquid reaches the groundwater, it is diluted by the groundwater ugh diffusion. In addition, the radioactive constituents in the liquid undergo radioactive decay.

filtering action and ion exchange action of the soil on particulates and solubles, respectively, he discharged liquid are neglected.

coefficients of permeability for each beach and outwash sand and the structural backfill have n determined using constant head and falling head tests. The permeabilities obtained during ing ranged between 1.2 x 10-4 to 2.7 x 10-3 cm/sec for the beach and outwash sand and ween 1.6 x 10-4 to 4.0 x 10-4 cm/sec for structural backfill. The coefficients of permeability for beach and outwash sand and the structural backfill are assumed equal 10-3 cm/sec.

ause the normal groundwater level at the location of the boron recovery tank is at elevation feet and Niantic Bay is at Elevation 0 feet, the hydraulic gradient along the flow path is:

22 - = 0.0179 or 1.79% (2.4.13) i = -----------

1230 effective porosity, ne, determined by porosity tests of soil samples from the site, equaled 0.1.

seepage velocity in the groundwater is given by Darcy's Law:

k -5 (2.4.14) 3.28x10 x 0.0179- = 5.87x10 - 6 ft/sec u = -----i = -----------------------------------------------

ne 0.1 time for the discharged liquid to travel from the boron recovery tank to the point of discharge Niantic Bay is given by:

28/18 2.4-25 Rev. 31

u 5.87x10

- 6 dispersion coefficients are related to the flow velocity by the dispersivity (Bredehoeft and der 1973), i.e:

K x, y = x, y u (2.4.16) re:

Kx,y = The horizontal dispersion coefficients; Kx is the component in the direction of the flow, Ky is in the direction perpendicular to the flow x,y = The corresponding longitudinal transverse components of the dispersivity u = Seepage velocity ues are assigned to, based on a best fit between the results of a mathematical model and the d data for the Snake River Plain aquifer (Robertson 1974). The former is an analytical roach to the three dimensional dispersion problem which simulates the continuous release of a taminant in a vertical line source. This calibration establishes a value for of 59 feet.

dehoeft and Pinder (1973) suggest the relation:

10 x = ------ y (2.4.17) 3 se results are generalized to other sites by assuming that, all other properties being equal, the perty of an aquifer that fixes the dispersivity is the porosity, such that:

n es (2.4.18) y = ys -------

ne re:

28/18 2.4-26 Rev. 31

ys = Transverse dispersivity for Snake River aquifer ne = Effective porosity for the aquifer of interest nes = Effective porosity for Snake River aquifer ause the local groundwater velocity (Equation 2.4.16) can be used to compute the horizontal ersion coefficients, it is subsequently assumed that Kz = ky.

the liquid from the boron recovery tank reaches the groundwater, several factors contribute to ispersion and dilution. These include advection, hydraulic dispersion, radioactive decay, and exchange. If the fluid flow is uniform, steady, and parallel to the x-axis, the hydraulic ersion coefficients are homogeneous, anisotropic and orders of magnitude greater than the ecular diffusion coefficients, and the radioactive decay and sorption processes are not sidered, the equation governing the distribution of contaminant is:

2 2 2 C + u ------

---

C C C C M' (2.4.19)

= K x ------- + K y --------- + K z --------- + ------

t x x y 2

z 2 ne re:

C = Contaminant concentration u = Seepage velocity M' = Rate of release of mass per unit volume of aquifer solution of Equation 2.4.19 for an instantaneous volume source in an aquifer of finite depth (2.4.20)

Co x - ut + l/ 2 x - ut - l/ y + b/ 2 y -b /2

- - erf -------------------------2 . erf ---------------------

C= ------ erf ------------------------- - .

- - erf ---------------------

4 1/2 1/2 1/2 1/2

( 4K x t ) ( 4K x t ) ( 4K y t ) ( 4K y t )

H2 - H1 nz 1- nH 2

---

nH 1 . n 2

Kt H

- + 2 H n H cos --------

- sin ------------- - sin -------------

H exp - -----

H z n=1 re:

28/18 2.4-27 Rev. 31

l, b = Source dimensions in the x and y direction, respectively H1, H2 = Upper and lower surface of the volume source H = Aquifer thickness x, y, z = Coordinates in the longitudinal, transverse, and vertical direction, respectively t = Time from initial release en input data are substituted in Equation 2.4.9, the minimum dilution factor for the undwater, Co/C, equals 73.

discharged liquid on reaching Niantic Bay is diluted further in that body of water. The hod used to calculate the dilution in Niantic Bay and Long Island Sound is the same method as cribed in Section 2.4.12. The only difference is that the released point is in the intake area ead of the circulating water discharge tunnel. The dilution factor upon entering Niantic Bay at Intake area is calculated to be 13,052 and at 1,000 feet from the point of discharge into Niantic is calculated to be 32,151. One-thousand feet was chosen arbitrarily as the point to calculate dilution factor in Niantic Bay so as to show the large dilution factor obtained in the bay.

12.4 Monitoring or Safeguard Requirements ce the potential for groundwater contamination is minimal, as discussed in Sections 2.4.13.2 2.4.13.3, procedures and safeguards to protect groundwater users are not necessary.

12.5 Design Bases for Subsurface Hydrostatic Loading re is no safety related permanent dewatering system for lowering groundwater levels for lstone 3. Safety related structures are designed for water pressure and buoyancy forces applied m their respective foundation levels to the design piezometric surface levels, as shown in ure 2.5.4-37 assuming saturated soil conditions to the water surface. Section 2.5.4.6 includes a ussion of groundwater conditions with respect to plant structure design and construction and tion 3.4 includes a discussion of flood design for Seismic Category I structures and ponents. Section 9.3.3 includes a description of the sump systems installed in the ESF lding for removal of groundwater inleakage collected in the porous concrete groundwater p.

13 TECHNICAL SPECIFICATION AND EMERGENCY OPERATION REQUIREMENTS rder to minimize the water associated impact of adverse hydrologically related events on ty related equipment and facilities, Millstone 3 has no related Technical Specification ussion. However, Technical Requirements Manual 3/4.7.6, Flood Protection, describes the sures required to provide flood protection for the service water pump cubicles.

28/18 2.4-28 Rev. 31

d protected portion of the circulating and service water pumphouse (Sections 2.4.1.1 and 1). Other safety related structures and components are protected from flooding by the site de of elevation 24.0 feet msl. AOP 3569 addresses safety measures to be taken in the case of ere weather conditions. These measures ensure that all watertight doors are in place and the p cubicle sump drain lines are isolated and thus all safety-related structures and components protected from flooding.

tion 2.4.2.3 states that there is no water associated impact in the safety related facilities, lting from local rainfall as severe as the probable maximum. Therefore, no technical cifications or emergency operating procedures are required, except as discussed above for the phouse.

14 REFERENCES FOR SECTION 2.4 1 Bechtel Corporation 1972. Final Safety Analysis Report, Millstone Nuclear Power Station, Unit 2, Docket No. 50-336, Sections 2.5 and 2.7.

2 Bodine, B.R. 1971. Storm Surge on Gulf Coast: Fundamentals and Simplified Predictions. Technical Memorandum 35. U.S. Army Corps of Engineers, Coastal Engineering Research Center, Washington, D.C.

3 Bredehoeft, J.D. and Pinder, G.F. 1973. Mass Transport in Flowing Groundwater. Water Resources Research, Vol 9, p 194-210.

4 Bretschneider, C.L. 1954a. Field Investigation of Wave Energy Loss of Shallow Water Ocean Waves. Technical Memorandum 46. U.S. Army Corps of Engineers, Beach Erosion Board, Washington, D.C.

5 Bretschneider, C.L. 1954b. Generation of Wind Waves Over a Shallow Bottom.

Technical Memorandum 51. U.S. Army Corps of Engineers, Beach Erosion Board, Washington, D.C.

6 Bretschneider, C.L. 1972. The Nondimensional Stationary Hurricane Wave Model.

Offshore Technology Conference, Preprint No. OTC 1517, Houston, Texas.

7 Bretschneider, C.L. and Collins, J.I. 1963. Prediction of Hurricane Surge: An Investigation for Corpus Christi, Texas, and Vicinity. NESCO Technical Report SN-120.

National Engineering Science Co. for U.S. Army Engineering District, Galveston, Texas.

8 Bretschneider, C.L. and Reid, R.O. 1954. Modification of Wave Height Due to Bottom Friction, Percolation and Refraction. Technical Memorandum 45. U.S. Army Corps of Engineers, Beach Erosion Board, Washington, D.C.

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10 Chow, V.T. 1964. Handbook of Applied Hydrology. McGraw Hill.

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