ML23193A906

6 to Updated Final Safety Analysis Report, Chapter 2, Site Characteristics

ML23193A906
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Site:	Millstone
Issue date:	06/28/2023
From:	Dominion Energy Nuclear Connecticut
To:	Office of Nuclear Reactor Regulation
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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

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

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

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

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

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

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

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

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 < 2FRACTION 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

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)

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)

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)

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

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

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

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

List of Figures (Continued) mber Title 3 Locations of Hydrographic Field Survey Stations, June to October 1965 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

List of Figures (Continued) mber Title 27 Inputs to One Dimensional Setdown Model 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

List of Figures (Continued) mber Title 1-16 Contour Diagram of Poles to Joint Planes - Final Grade 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

List of Figures (Continued) mber Title 4-13 Geologic Map of Final Grade, Northeast Quadrant of Containment Walls 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

List of Figures (Continued) mber Title 4-41 Shorefront and Dredging Plan 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'

List of Figures (Continued) mber Title 4-67 Geologic Profile Section N-N' 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

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.

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.

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.

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.

nt fuel is selected based on the Unit 3 spent fuel strategy and the NUHOMS Technical cification requirements for fuel qualification. The Dry Shielded Canister (DSC) consists of a l and basket assembly, which can accommodate 32 fuel assemblies. The DSC is inserted into ansfer cask and placed in the cask pit area of the Unit 3 spent fuel pool for fuel loading. Once ed, the transfer cask/DSC is ready for draining, drying, closure operations and ontamination in the Unit 3 fuel building. The transfer cask is utilized to transfer the loaded C from Unit 3 to the ISFSI pad for loading into an Horizontal Storage Module (HSM). The M array consists of precast concrete components forming a series of concrete storage modules dry shielded canisters storing spent fuel.

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.

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 ected to decrease in population. By the year 2010 (the last year of projections), the town's ulation is projected to be 18,080 (Connecticut Office of Policy and Management, Interim 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

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.

3.3 Transient Population 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

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 ns where the economic and social relationships meet the specified criteria of metropolitan racter and integration.

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.

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.

6 Rhode Island Department of Administration, Projections by County, 1990-2020, 1989.

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.

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.

TOTAL POPULATION  % CHANGE MUNICIPALITY 1960 1970 1980 1990 1960-1970 1970-1980 1980-1990 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.

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

Distance to Plant Sector 0-1 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8-9 9-10 TOTA N 16 722 866 784 116 213 542 209 536 1,717 5,721 NNE 13 359 1,146 1,978 1,861 1,622 1,666 2,242 2,192 3,142 16,221 NE 165 455 839 3,888 10,584 7,752 8,164 8,129 911 1,961 42,848 ENE 22 455 292 4,963 971 7,186 3,748 3,047 1,008 2,662 24,354 E 0 636 413 1,804 193 552 0 63 1,434 904 5,999 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 1,682 W 0 178 1,061 1,014 440 763 475 562 881 408 5,782 WNW 0 476 1,165 1,964 346 239 211 1,654 509 417 6,981 NW 0 634 873 1,192 1,140 644 599 101 209 81 5,473 NNW 148 314 892 522 646 918 221 429 456 314 4,860 Total 364 4,372 8,086 18,200 16,383 20,201 16,098 16,594 8,251 11,894 120,443

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,

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

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

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

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

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

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

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

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

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

Sector 0-1 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8-9 9-10 Total 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 21,773 Note: Includes student enrollment only.

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

Sector 0-1 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8-9 9-10 Total 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 15,120 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 20,046 Note: Firms with 50 employees or more. Excludes plant employee population.

Sources: Telephone survey conducted in March 1992.

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.

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.

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.

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

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

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.

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.

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

Sector 0-1 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8-9 9-10 Averag 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.

Sector 0-1 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8-9 9-10 Averag 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.

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.

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.

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

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

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

FIGURE 2.1-3 SITE LAYOUT FIGURE 2.1-4 SITE PLAN

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

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.

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.

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

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

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.

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.

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.

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

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)

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)

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:

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

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).

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)

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

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).

thheld under 10 CFR 2.390 (d)(1) 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

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.

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):

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

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.

perature of 30C (80F), 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)

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.

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.

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.

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.

ANGLE Postulated Missile Type (Table A)

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

Anhydrous ammonia 264 803 - -

FIGURE 2.2-1 MAJOR INDUSTRIAL, TRANSPORTATION AND MILITARY FACILITIES FIGURE 2.2-2 INSTRUMENT LANDING PATTERNS AT TRUMBULL AIRPORT

CONTROL ROOM 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

ropical origin affects the Millstone site region.

1.1.2 Temperature, Humidity, and Precipitation mean annual temperature is approximately 51F 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 3F to 5F cooler than nearby inland stations. Temperatures of 90F or greater ur an average of seven days per year at Bridgeport, while temperatures of 100F or greater e occurred only in July and August; with an extreme maximum of 103F 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 -20F 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.

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

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).

udy 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).

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.

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).

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

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.

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.

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 ur. 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.

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.

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 0C.

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

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.

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.

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.

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.

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.

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)

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)

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

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)

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

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

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

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 T 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,

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

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

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

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

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)

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)

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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)

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)

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

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

E. Episodes of Ambient Temperature Below 0.0F:

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

E. Episodes of Ambient Temperature Below 0.0F:

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

F. Episodes of Ambient Temperature Above 86.0F:

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

F. Episodes of Ambient Temperature Above 86.0F:

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

ABLE 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

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

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

TABLE 2.3-23 WIND DIRECTION/STABILITY CLASS/VISIBILITY JOINT FREQUENCY DISTRIBUTION AT MILLSTONE CLICK HERE TO SEE TABLE 2.3-23

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

CLICK HERE TO SEE TABLE 2.3-24

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

CLICK HERE TO SEE TABLE 2.3-25

ABLE 2.3-26 MILLSTONE STABILITY CLASS DISTRIBUTION USING DELTA-T FOR STABILITY DETERMINATION CLICK HERE TO SEE TABLE 2.3-26

ABLE 2.3-27 MILLSTONE STABILITY CLASS DISTRIBUTION USING SIGMA THETA FOR STABILITY DETERMINATION CLICK HERE TO SEE TABLE 2.3-27

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

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

TABLE 2.3-30 SEASONAL AND ANNUAL ATMOSPHERIC MIXING DEPTHS AT MILLSTONE CLICK HERE TO SEE TABLE 2.3-30

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

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

TABLE 2.3-33 MONTHLY

SUMMARY

OF DATA RECOVERY RATES/

METEOROLOGICAL SYSTEM CLICK HERE TO SEE TABLE 2.3-33

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

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.

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.

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.

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

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.

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

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

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

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.

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 pendent 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:

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:

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),

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.

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

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

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).

inforced 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.

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.

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

temperature extremes of the water in Niantic Bay and Long Island Sound are 80F maximum 33F 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

-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 - - --------

Pa 1 - (2.4.8)

- + fu + -------------------- - b y t x y y y h + w y 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)

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

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.

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

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.

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:

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:

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 2

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:

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.

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.

10 Chow, V.T. 1964. Handbook of Applied Hydrology. McGraw Hill.

11 Department of the Army 1952, Rev. 1965. Standard Project Flood Determinations. Civil Engineer Bulletin No. 52-8. Washington, D.C.

12 Ebasco Services Incorporated 1966. Design and Analysis Report, Millstone Nuclear Power Station, Unit 1, Docket No. 50-245, Section II-5.0, Geology and Seismology.

13 Essex Marine Laboratory 1965. Study on Current Velocity, Temperature and Salinity Measurement in the Millstone Point Area. Wesleyan University, Middletown, Conn.

06457.

14 Freeman, J.C. Jr; Baer, L; and Jung, G.H. 1957. The Bathystrophic Storm Tide. Journal of Marine Research, Vol 16, No. 1.

15 Goldsmith, R. 1960. Surficial Geologic Map of the Uncasville Quadrangle, Connecticut, U.S. Geologic Survey, Quadrangle Map, GQ-138, Washington, D.C.

16 Hansen, E.M., Schreiner, L.C., and Miller, J.F. 1982. Application of Probable Maximum Precipitation Estimates - U.S. East of the 105th Meridian. Hydrometeorological Report No. 52. National Weather Service, NOAA, U.S. Department of Commerce, Washington, D.C.

17 Harris, D.L. 1963. Characteristics of the Hurricane Storm Surge. Technical Paper No.

48. U.S. Weather Bureau (now NOAA), Washington, D.C.

18 Harrison, W. and Wilson, W.S. 1964. Development of the Methods for Numerical Calculation of Wave Refraction. Technical Memorandum 6. U.S. Army Corps of Engineers.

19 Housing and Home Finance Agency 1952. Snow Load Studies, Housing Research Paper 19, Washington, D.C.

20 Liang, H.C. and Tsai, C.E. 1979. Far-Field Thermal Plume Prediction for Units 1, 2, and 3, Millstone Nuclear Power Station, NERM-49, Stone & Webster Engineering Corp.,

Boston, Mass.

21 Marinos, G. and Woodward, J.W. 1968. Estimation of Hurricane Surge Hydrographs.

Journal of Waterways Harbors Division, ASCE, Vol 94, WW2, 5945, p 189-216.

22 National Oceanic and Atmospheric Administration 1968. Interim Report -

Meteorological Characteristics of the Probable Maximum Hurricane, Atlantic and Gulf

23 Northeast Utilities Service Company 1975. Summary Report, Ecological and Hydrographic Studies, May 1966 through December 1974. Millstone Nuclear Power Station, Berlin, Conn.

24 Putnam, J.A. and Johnson, J.W. 1949. The Dissipation of Wave Energy by Bottom Friction. Trans. American Geophysical Union, Vol 30, No. 1.

25 Redfield, A.C. and Miller, A.R. 1957. Water Levels Accompanying Atlantic Coast Hurricanes. Meteorological Monographs, Vol 2, No. 10. American Meteorological Society, Boston, Mass.

26 Robertson, J.B. 1974. Digital Modeling of Radioactive and Chemical Waste Transport in the Snake River Plain Aquifer at the National Reactor Testing Station, Idaho, USGS IDO-22054. U.S. Geologic Survey, Washington, D.C.

27 Schreiner, L.C. and Riedel, J.T. 1978. Probable Maximum Precipitation Estimates, U.S.

East of the 105th Meridian. Hydrometeorological Report No. 51. National Weather Service, NOAA, U.S. Department of Commerce, Washington, D.C 28 Adams, E. E. 1999. Historical Review of Dilution Calculations for Millstone Nuclear Power Station, MIT, Cambridge, Mass.

29 US Army Corps of Engineers 1965. Hurricane Protection Project Design Memorandum No. 1. New London Hurricane Barrier. New England Division, Waltham, Mass.

30 US Army Corps of Engineers 1977. Shore Protection Manual. Coastal Engineering Research Center, Fort Belvoir, Va.

31 US Coast and Geodetic Survey 1965. Study on Tidal Current Data. In Units 1 and 2 Environmental Report Docket No. 50-245 and 50-336, Appendix B, Section III-H, Washington, D.C.

32 US Weather Bureau (now NOAA) 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 />. Hydrometeorological Report No. 33, Washington, D.C.

33 Wilson, B.W. 1955. Graphical Approach to Forecasting of Waves in Moving Fetches.

Technical Memorandum 73. U.S. Army Corps of Engineers, Beach Erosion Board, Washington, D.C.

34 Wilson, B.W. 1963. Deep Water Wave Generation by Moving Wind Systems. ASCE Transaction 128, Part IV, p 104-131.

ABLE 2.4-1 CONNECTICUT PUBLIC WATER SUPPLIES WITHIN 20 MILES OF MILLSTONE 3 CLICK HERE TO SEE TABLE 2.4-1

BLE 2.4-2 MAXIMUM WAVE HEIGHTS GENERATED BY SLOW, MEDIUM, AND HIGH SPEED STORMS (DEEP-WATER FETCH)

CLICK HERE TO SEE TABLE 2.4-2

TABLE 2.4-3 MAXIMUM SHALLOW WATER WAVES (AFTER REFRACTION)

SLOW SPEED PROBABLE MAXIMUM HURRICANE CLICK HERE TO SEE TABLE 2.4-3

TABLE 2.4-4 MAXIMUM SHALLOW WATER WAVES (AFTER REFRACTION)

MEDIUM SPEED PROBABLE MAXIMUM HURRICANE CLICK HERE TO SEE TABLE 2.4-4

BLE 2.4-5 MAXIMUM SHALLOW WATER WAVES (AFTER REFRACTION) HIGH SPEED PROBABLE MAXIMUM HURRICANE CLICK HERE TO SEE TABLE 2.4-5

TABLE 2.4-6 LOWEST TIDES AT NEW LONDON, CONNECTICUT 1938-1974 CLICK HERE TO SEE TABLE 2.4-6

LOCA Coincident with LOP Loss of Power (LOP Normal Normal Unit Minimum Normal Operating Cooldown Engineered Safety Engineered Safety Hot Cold Condition (1) Condition Features Features Shutdown Shutdo 6

(106 Btu/hr) (106 Btu/hr) (106 Btu/hr) (10 Btu/hr) (106 Btu/yr) (106 Btu/

Service Water 178.97 (2) (2) (2) (2) (2)

System Circulating Water 8,200 (3) 0 0 0 0 0 System (after RHR cooling commences)

TOTAL 8378.97 (2) (2) (2) (2) (2)

NOTES:

(1) These are maximum heat loads.

(2) See Table 9.2-2.

(3) An approximate value for operation with 1 to 5 inches of backpressure on the turbine.

Usage Location Dilution Factor Travel Decay Time (hr) asure Beach 12.6 0.0 rkness Memorial 36.0 0.0 terford State Park 36.0 0.0 ean Beach Park 21.0 0.0 escent Beach 40.0 0.0 cky Neck State Park 30.0 0.0 Cook Point 43.0 0.0 ge of Initial Mixing Zone** 3.0 0.0 r Field 36.0 0.0 000 ft south of discharge)

TES:

or discharge from Millstone 2 and 3 For Millstone 2 and 3 operation within 500 to 1,000 ft from the discharge point (quarry cut)

Number and Size of Structure A* (ft) B* (ft) C* (ft) D* (lb/ft2) Scruppers ntrol Building 1.58 0.63 99 2 at 128 in2 = 256 in2 xiliary Building North 0.50 34 South 0.50 42 el Building El 106'-0" 1.65 108 El 101'-9" 1.67 109 El 93'-10" 1.88 122 El 61'-5" 1.15 88 in Steam Valve Building El 85'-11 1/4" 0.25 35 El 71'-2" 0.25 73 gineering Safety Features ilding El 56'-9" 0.75 47 ntainment Enclosure 2.06 0.83 118 8 at 128 in2 = 1024 ilding in2 culating and Service Water mphouse (CSWP)

El 39'-0" 1.98 1.31 87 El 26'-0" 1.31 87 drogen Recombiner 0.92 57 2 at 90 in2 = 180 in2 ilding TES:

Difference between drain low point and top of parapet.

Difference between drain low point and top of lowest roof curb.

Difference between drain low point and bottom of overflow scupper.

Maximum load (lb/ft2) applied by maximum ponding (assume that roof drains are clogged);

H2O @ 4C (62.4 pcf).

WHERE APPLICABLE A B A C

CSWP ROOF ONLY OTHER SAFETY RELATED STRUCTURE ROOFS

COMPUTATIONS Computed Flow (cfs)

Surface Area Concentration Time at Down stream End Drainage Basin (acre) (minutes) of Drainage Basin

& C1 (2) 9.58 14.8 267 6.43 12.6 351 TES:

rainage areas A and B are graded such that their flows do not contribute to the areas of safety related structures.

rainage areas C and C1 are conservatively combined to provide worst case water flows.

SAFETY-RELATED STRUCTURES Maximum W. S.

Elevation at Doors Drainage Basin Structure to Structure (ft msl)

C Auxiliary Building 24.85 C Control Building 24.27 C Emergency Generator Enclosure 24.27 D Main Steam Valve Building 24.85 D Hydrogen Recombiner Building 24.85 D Auxiliary Building 24.85 D Engineered Safety Features Building 24.85 D Fuel Building 24.85 D RWST/SIL Valve Enclosure 24.85 D Demineralized Water Storage Tank Block House 24.85

TABLE 2.4-12 ROOF AREA AND PONDING LEVEL DUE TO PMP (1)CATEGORY I STRUCTURES Other Roof/Area Total Area Peak Elevation Top Elevat Draining to this Considered Peak Flow of Water Elevation of Bott Plan Area of Structure's Roof (3) in Flow off Q=CIA(4) Parapet (ft, Surface (5) Scup Structures Roof (2) (ft2) (Structure/Ft2) Roof (ft2) (cfs) msl) (ft, msl) (ft, Control Bldg. 5,916 Turbine Bldg. / 2,587 8,503 13.74 92'-4" 92'-5" 91'-

Auxiliary Bldg.

North End 7,956 ----- 7,956 12.86 94'-0" (6) 94'-1 1/2" (7) -----

South End 7,912 Containment Encl. 12,445 20.11 93'-6" (6) 93'-10" (7) -----

Structure /4,247 Fuel Bldg. / 286 Fuel Bldg.

El 106'-0" 2,912 Cont. Enc. Strct. / 956 3,868 6.25 107'-4" 107'-5" -----

El 101'-9" 1,950 Fuel Bldg. / 443 2,393 3.87 103'-0" 103'-1" -----

El 93'-10" 4,352 Liq. Wst. Bldg. / 72 5,514 8.91 94'-8" 94'-9" -----

El 61'-5" 3,264 Fuel Bldg. / 3,942 7,846 12.68 56'-8 1/2" 56'-10 1/2" -----

Main Steam Valve Bldg.

El 85'-11 1/4" 2,900 Aux. Bldg. / 12,445 17,628 28.5 86'-2" 86'-8" -----

Cont. Encl. Strt. / 2,283 El 71'-2" 928 Main. Stm. Valve / 17,628 18,556 30.0 71'-7 5/8" 72'-2" -----

Eng. Safety Feat. 6,931 Cont. Strt. Enc. / 5,628 12,559 20.3 57'-3" 57'-4" -----

Bldg.

Cont. Strt. Encl. 18,252 ----- 18,252 29.5 187'-0" 186'-10" 185

Other Roof/Area Total Area Peak Elevation Top Elevat Draining to this Considered Peak Flow of Water Elevation of Bott Plan Area of Structure's Roof (3) in Flow off Q=CIA(4) Parapet (ft, Surface (5) Scup Structures Roof (2) (ft2) (Structure/Ft2) Roof (ft2) (cfs) msl) (ft, msl) (ft, Hyd. Rec. Bldg. 2,104 Cont. Strt. Enc. / 1,327 4,029 6.5 51'-10" 51'-11" -----

ESF Bldg. / 598 Circ. and SW Pumphouse El 39'-0" 10,126 ---- 10,126 16.4 40'-3 1/2" 40'-7" -----

El 26'-0" 612 C&SW Pumphse / 840 1,452 2.4 27'-3 1/2" 27'-7" -----

1. Based on HMR 51/52.

2. From SWEC Drawing No. 12179-EA-20A-1.

3. Effective area.

4. C = 1.0; i = 70.4 in./hr (peak 5 min. period); A = total runoff area flowing over parapet.

5. Assume entire length of parapet as weir.

6. Elevation of curb at low point.

7. Over curb at low point; all other flow on roof is sheet flow.

TABLE 2.4-13 OVERFLOW LENGTH OF THE PARAPET WALL ON THE ROOF USED IN PMP ANALYSIS - CATEGORY I STRUCTURES CLICK HERE TO SEE TABLE 2.4-13

FIGURE 2.4-1 FACILITIES LOCATED ON THE SITE

LABORATORY

FIGURE 2.4-7 SITE GRADE AND DRAINAGE BASINS FOR PMP RUNOFF ANALYSIS

SLOW SPEED OF TRANSLATION MEDIUM SPEED OF TRANSLATION HIGH SPEED OF TRANSLATION

EAST SOUTH SOUTH SOUTH

FIELD WIND FIELD - MILLSTONE

FIGURE 2.4-33 PROBABLE SEEPAGE PATH FROM BORON RECOVERY TANK AND WASTE DISPOSAL BUILDIN TO LONG ISLAND SOUND

BUILDINGS BUILDING

ROOM s section provides information regarding seismic, geologic, and geotechnical characteristics of site and the surrounding region.

following companies and personnel performed tests on materials from the site:

1. American Drilling and Boring Company, Providence, Rhode Island, under the direction of Stone & Webster Engineering Corporation (S&W), drilled test borings, performed standard penetration tests, sampled soil, cored rock, performed pressure tests on selected holes, and installed piezometers.

2. Weston Geophysical Engineers, Incorporated, Westboro, Massachusetts, conducted cross-hole and down-hole surveys and refraction and reflection surveys to determine in situ seismic wave velocities and the varying depths to founding strata. S&W performed additional cross-hole surveys using an impact source.

3. Geotechnical Engineers, Inc., Winchester, Massachusetts, performed cyclic triaxial and resonant column tests on beach sands in the vicinity of the circulating and service water pumphouse.

4. Geochron Laboratories, Cambridge, Massachusetts, performed potassium-argon (K-Ar) dating to determine the age of rock and fault gouge samples.

5. Dr. R. T. Martin, Massachusetts Institute of Technology, Cambridge, Massachusetts, and Dr. R. C. Reynolds of Dartmouth College, Hanover, New Hampshire performed x-ray diffraction tests to determine the clay mineral composition of the fault gouge samples.

6. Dr. R. A. Wobus, Williams College, Williamstown, Massachusetts, performed petrographic analysis of thin sections from fault zones.

7. Dr. E. Ingerson, University of Texas, Austin, Texas, analyzed quartz crystals found in the fault zone to determine the conditions of formation.

8. Dr. D. W. Caldwell, Groton, Massachusetts, performed consulting services to determine the age of till at the Millstone site.

9. Dr. K. Tsutsumi, Tufts University, Medford, Massachusetts, performed unconfined compression strength tests on rock specimens taken from borings.

10. Dr. Robert F. Black, University of Connecticut, Storrs, Connecticut, performed consulting services regarding the age and origin of features found in site glacial deposits.

information contained in this section was obtained from the following:

2. Detailed mapping of rock after the removal of overburden and the excavation of structures.

3. Interviews with authorities on regional geology.

4. Rock and soil borings.

5. Laboratory tests of representative soil and rock samples.

6. Interpretation of aerial photographs, Earth Resources Technology Satellite (ERTS) imagery, gravity, and aeromagnetic maps.

7. Geophysical surveys on the site.

8. Piezometer installations and groundwater monitoring.

9. Bedrock pressure testing (holding test and pressure flow test).

10. Age dating of rock samples.

11. Fluid inclusion studies.

12. Petrographic studies.

13. Blast monitoring.

site is located on a low peninsula on the north shore of Long Island Sound and the east shore he Niantic River. Bedrock is highest on the eastern portion of the site and dips to the west ards Long Island Sound. The reactor containment and most other Category I structures on the ern side of the site are founded on bedrock, whereas the control, emergency generator, waste osal enclosure, turbine building, are founded on dense basal till which overlies the rock. The ulating and service water pumphouse is also founded on bedrock. The bedrock surface falls sharply from the main site area to approximately el -32 feet in the area of the pumphouse.

tion 2.5.1 presents the regional and site area geology and geologic history. A discussion of onal faulting and tectonics and their relationship to rock types at the site is discussed in detail.

tion 2.5.2 presents the regional seismicity and describes the selection of the site safe shutdown hquake (SSE) of 0.17 g and the operating basis earthquake (OBE) of 0.09 g.

tion 2.5.3 describes the faulting encountered at the site during construction. A description of origin and nature of the faults mapped at final excavation grades is included in this section.

il, and stability and liquefaction analyses based on these studies are also included in this ion, as well as maps and tables from the geological mapping program.

tion 2.5.5 presents the results of stability analyses on two safety related slopes at the site: the tainment excavation and the shoreline slope.

bankments or dams (Section 2.5.6) are not included in the plant design.

shown on Figure 2.5.1-1 the site lies in the Seaboard Lowland section of the New England siographic province. The site is located in a geologically complex region characterized by amorphosed and folded rocks of Ordovician-Silurian age. This area has been affected by four genies: the Avalonian (575 million years ago m.y.a.), the Taconian (465-445 m.y.a.), the dian (400-370 m.y.a.), and the Alleghenian (230-260 m.y.a.). The surrounding region has also n affected by rifting ranging in age from Triassic to Jurassic. Since then the region has been le, with the exception of epeirogenic uplift during Cretaceous and Tertiary times, and isostatic ound, resulting from the removal of the weight of ice covering the region during Pleistocene e.

site lies in an area of low seismic activity. Only 13 earthquakes of Intensity V, Modified calli (MM) or greater, have been recorded within a distance of 50 miles of the site in more 300 years. The nearest significant earthquake was at East Haddam, Connecticut, in 1791. Its enter was approximately 25 miles north of the site. Even though this earthquake is recorded in Earthquake History of the United States (USCGS 1965) as having an intensity of VIII MM, iled studies by Rev. Linehan, Director, Weston Geophysical Observatory, based on newspaper ounts and other records of the time, indicate that the intensity was no higher than VI to VII

. Maximum intensity of ground motion experienced at the site in approximately 300 years of rded history has not exceeded Intensity V MM, which would correspond to an acceleration of to 0.03g.

lts believed to be related to Triassic tectonics have been found in the excavation for Millstone otassium-argon methods of dating clay gouge found within the faults indicate that the last vity along these faults occurred approximately 142 m.y.a.; therefore, these faults are not able features (NNECO. 1975, 1976, 1977, 1982). There is no capable fault at or near the site.

hick layer of very dense basal till blankets the site. The bedrock surface is irregular and was ially smoothed. Most major plant safety related structures are founded on hard, crystalline rock. The control building is founded on structural backfill overlying till and bedrock.

re has been no commercial mining in the area other than the now inactive granite quarry, ted approximately 1,200 feet to the southeast of the Millstone 3 plant area. The soils and rock erlying the site are strong, stable materials that are not susceptible to loss of strength, sidence, or other instabilities during earthquake motion. The gradation and the density of the are such that liquefaction is precluded. The soils and rock underlying the site are of very low meability. The groundwater table is highest in the northern part of the site and slopes gradually ards the shoreline. There are some isolated wells in the area; however, there is no industrial, estic, or municipal use of groundwater from these wells.

1.1 REGIONAL GEOLOGY w England is characterized by a series of intensely folded anticlinoria and synclinoria trending he northeast. The geology of these folds has been made more complex by igneous activity, amorphism, and faulting. Extensive glaciation has modified landforms and deposited or

ions that follow.

1.1.1 Regional Physiography and Geomorphology Millstone site is located in the Seaboard Lowland section of the New England physiographic vince (Figure 2.5.1-1). The New England province is divided into five sections by Fenneman 38): the Taconic, the Green Mountain, the White Mountain, the New England Upland, and the board Lowland. The Connecticut Valley Lowland is discussed by Fenneman (1938), but not sidered as a separate province. Just southwest of Millstone Point along the coast of necticut lies the Coastal Plain province. These sections are not necessarily characterized by orm geological terrain, but are defined primarily by similar topographic expression.

tion 2.5.1.2 discusses the local physiography and its significance to the site.

Seaboard Lowland section is a smooth, low-lying belt extending from Connecticut north to w Brunswick. In Connecticut, the Lowland varies in width from 6 to 16 miles, and as it swings hward in Rhode Island and Massachusetts, it widens to approximately 50 miles in theastern Massachusetts. The relatively low altitude of the seaboard section is not primarily to a difference in rock resistance, though the parts underlain by the Carboniferous sediments lower and flatter than the rest (Fenneman 1938). Along Long Island Sound, it is probable that rrow zone was covered by Cretaceous formations of the coastal plain (Fenneman 1938). This e has a steeper seaward slope than the upland and is considered by Fenneman (1938) to be part he pre-Schooley peneplain. In the Millstone site area, this zone is characterized by glacial wash and moraines with some swamp deposits.

Taconic section, the westernmost subdivision of the New England province, extends from roximately 12 miles southeast of Poughkeepsie, New York, northward to approximately land, Vermont. The zone is fairly narrow with a maximum width of about 25 miles, and the is mostly mountainous. The mountains consist mainly of strongly metamorphosed sediments, predominantly schists and slates.

Green Mountain section borders the Taconic section to the northeast. This highland section nds from western Massachusetts into Canada. The Green Mountains are underlain by resistant talline rocks of Precambrian age.

White Mountain section consists of a series of mountain ranges from the White Mountains of w Hampshire northeastward to the Katahdin group in Maine. This section is underlain mainly metamorphosed sedimentary and volcanic rocks of Paleozoic age and igneous rocks of the ite Mountain Plutonic-Volcanic series (Billings 1956).

New England Upland section, the largest section of the New England physiographic vince, extends from Canada to the Highlands area of southeastern New York and northern w Jersey. This section typically reflects underlying fold belts and has the appearance of a eau dissected by narrow valleys and containing scattered monadnocks (Fenneman 1938). It first believed that a single peneplain existed at one time and extended from Long Island

exact origin of the peneplain is still questioned. Two hypotheses have been brought forth for origin of the plateau: marine terracing and terracing by normal erosion (Fenneman 1938).

ther explanation is widely accepted, although a combination of the two seems more plausible.

Connecticut Valley Lowland trends northerly through the New England Upland section from Connecticut shore to just north of Greenfield, Massachusetts. The Lowland is underlain by dstone, conglomerate, and shale, which is less resistant to weathering, and diabase which is e resistant. There is an abrupt change to crystalline rocks on both sides of the depression.

th of the New England Lowland section is the Atlantic Coastal Plain physiographic province.

s section (Figure 2.5.1-1) encompasses Cape Cod, Long Island, southern New Jersey, and the hore islands and shoals. In the site area, the Coastal Plain sediments are submerged by the antic Ocean. These sediments are of late Cretaceous and Tertiary ages and thicken seaward.

ure 2.5.1-2 shows a distribution of pre-Pleistocene sediments off the New England coast. The ement is believed to be a continuation of that found underlying southern New England.

ciation has greatly changed much of New England. The rock outcrops have been rounded and othed and the valleys filled with glacial deposits. The rivers in many cases had to develop channels after being dammed by glacial deposits.

stocene glacial deposits are widespread throughout New England. End moraines occur along southern margins and are prominent along Long Island, Block Island, Martha's Vineyard, e Cod, and in southern Rhode Island and Connecticut (Schafer and Hartshorne 1965). End aines have been mapped in the site area by Flint (1975) and Goldsmith (1964) and are shown he Site Surficial Map (Figure 2.5.1-3).

1.1.2 Regional Structure Millstone site area lies in the northern portion of the Appalachian Mountain system. The alachians extend from Alabama to Newfoundland as a series of ranges formed by a number of cessive deformations during the Paleozoic era.

northern Appalachians can be separated into a number of distinct geologic sections. The ternmost area, the foreland, is relatively undeformed. This area includes the Catskill Plateau, Hudson-Champlain and the St. Lawrence Lowlands, and consists mainly of gently dipping, mentary rocks of Early Paleozoic age.

arrow belt of deformed and metamorphosed lower Paleozoic carbonate rocks, east of the land, forms the northern extension of the Valley and Ridge province. These rocks are similar hose of the Catskill Plateau: however, they have undergone at least two deformations and have n broken by thrust faults and high-angle gravity faults.

westward into place above middle Ordovician shales (Figures 2.5.1-4 and 2.5.1-5).

New England section is a series of north-south anticlinoria and synclinoria that parallel the eral trend of the Appalachian Mountain belt. They are, from west to east: the Green Mountain clinorium, the Connecticut-Gaspe synclinorium, the Bronson Hill anticlinorium, the rimack synclinorium, and the Rockingham anticlinorium, the Merrimack synclinorium, and Rockingham anticlinorium. The Merrimack synclinorium in southeastern New England ends uptly on the east along the Clinton-Newbury and Lake Char fault zones. East of the fault zone a belt of Precambrian and Lower and Middle Paleozoic igneous and metamorphic rocks of ous lithologies. Figure 2.5.1-4 shows the major stratigraphic units associated with these ctural belts and Figure 2.5.1-5 shows the structural units.

Green Mountain anticlinorium is made up of a series of massifs that are intensely sheared and amorphosed Paleozoic rocks with a Precambrian core. They are, from north to south: the en Mountain, the Berkshire, and the Housatonic massifs.

Hudson Highlands group of rocks including schists, gneisses, granites, and minor marbles of cambrian age are exposed along much of the anticlinorium. This structural high is believed to arate the miogeosynclinal sequence on the west from the eugeosynclinal sequence on the east.

eugeosynclinal sequence is generally considered as a homoclinal sequence, of intensely ed and sheared rocks of early Paleozoic age. In the trough of the Connecticut-Gaspe clinorium is a series of domes surrounded by the entire synclinorial sequence. The clinorium is a major tectonic unit that extends from Long Island Sound along the Connecticut er to the Gaspe Peninsula and into Newfoundland. The east limb is masked by the younger tic sediments and basalt flows of the Connecticut Valley Triassic Basin.

crest of the Bronson Hill anticlinorium coincides with an echelon series of Ordovician gneiss es (Naylor 1968, Thompson et al., 1968). The metamorphosed sediments and volcanic rocks rdovician and Devonian ages are stratigraphically continuous with those of the Connecticut-pe synclinorium. The gneiss domes are believed to have been the loci of volcanic islands hin the eugeosynclinal trough during Early Paleozoic time (Naylor 1968, Thompson et al.,

8).

Merrimack synclinorium shares its west limb with the Bronson Hill anticlinorium, which udes metamorphosed lower and middle Paleozoic clastic sediments. Metamorphism and onism have greatly confused the geology of the area. Metamorphic grade increases from north outh within the synclinorium. The synclinorium has been intruded by rocks belonging to the onian New Hampshire Plutonic series (Billings 1956, Page 1968, Foland et al., 1971). The thern extent of the Merrimack synclinorium is obscured by the Honey Hill fault and the local ing and refolding of the Ordovician rocks south of the Honey Hill fault.

ozoic metamorphic units of primarily sedimentary origin.

Merrimack synclinorium and the Rockingham anticlinorium end abruptly along the Clinton-wbury fault zone. East of this fault and the Lake Char fault lies a belt of Precambrian and lower middle Paleozoic igneous and metasedimentary rocks. Granites, granite gneisses, schists, and anic deposits are characteristic of this area. The Precambrian basement of southeastern New land is younger than that of the Green Mountains to the west (Naylor 1975). The geologic ain in this southeastern New England belt is comparable to that of the Avalon Peninsula in wfoundland (Rodgers 1972). A number of Late Paleozoic basins have been superimposed on e rocks: Boston, Norfolk, Woonsocket, North Scituate, and Narragansett Basins. The ragansett Basin is slightly to moderately metamorphosed with a maximum staurolite grade in southwest corner (Weston Observatory 1976). The Boston Basin is only slightly amorphosed (Rodgers 1970).

ng the southern New England coast is an east-west belt of rocks extending eastward from the ern edge of the Connecticut Valley Triassic Basin (Figure 2.5.1-4). In Connecticut, the strip is e up of complexly folded metasediments and a number of gneiss domes. The domes range in from late Precambrian to early Paleozoic (Naylor 1968, Rodgers 1970). The Millstone site is ted in this region adjacent to the Lyme Dome (Section 2.5.1.2). In Rhode Island, the strip sists of massive, relatively undeformed Late Pennsylvanian or Early Permian granites rragansett Pier and Westerly Granite) which intrude the Narragansett Basin deposits, and cambrian gneisses.

taceous and post-Cretaceous sediments have masked the seaward extension of the alachian structures to the south and east. Figure 2.5.1-2 shows the inferred distribution of the stal plain material. Figure 2.5.1-5 shows what is considered to be the seaward thickening ge of Cretaceous, Tertiary, and Quaternary sediments dipping to the southeast. These ments unconformably overlie the pre-Cretaceous rock surface that dips seaward at a low le. Recent work by Sheridan (1974) indicates that there are some very deep, possibly fault-nded basins beneath the outer shelf and beyond, containing carbonates and evaporates of ssic-Triassic and Permo-Carboniferous age (Figure 2.5.1-6). A number of somewhat lower Triassic and Permo-Carboniferous basins have been hypothesized in papers by Ballard Uchupi (1972, 1975) (Figure 2.5.1-6). Table 2.5.1-1 gives the lithologies, ages, and thickness he coastal plain sediments off the southern New England coast. Figure 2.5.1-2 shows the nt of the Cretaceous sediments and the unconformably overlying Tertiary sediments. A thin eer of reworked glacial outwash and clastic material covers most of the shelf area (Hoskins 7). Relief on the surface of the continental shelf of the Long Island, Block Island, and Rhode nd Sounds and in the Buzzards Bay area has been observed by seismic profiling. Tagg and upi (1967) believe these irregularities to be caused by fluvial erosion and modified by glacial ion and deposition.

physical studies in the Gulf of Maine indicate that its tectonic history is similar to that of the w England coast. Late Paleozoic and Early Mesozoic basins are also believed to exist in this (Ballard and Uchupi 1972, 1975). These structures are covered by differing amounts of post-

ments and the Tertiary-lower Pleistocene strata from the Pleistocene glacial deposits (Ballard Oldale 1973). Moraine deposits cover much of the Gulf of Maine and Georges Bank area llard and Oldale 1973). The topographic expression is believed by Ballard and Oldale (1973) e due to the result of stream erosion during Tertiary and early Pleistocene time.

1.1.3 Regional Stratigraphy generalized regional geologic map (Figure 2.5.1-4) shows the distribution of significant rock es in the region surrounding the Millstone site. The regional geologic section (Figure 2.5.1-5) taken trending east-west from the Appalachian Plateau in New York to the eastern edge of the ssic sediments and then southeastward through the Millstone site to the Coastal Plain ments.

regional stratigraphic correlation chart (Figure 2.5.1-7) gives a number of stratigraphic mns with correlations between regions of similar latitude as well as correlations between ons of similar longitude. Therefore, correlations are given parallel to and across the regional

d. Figure 2.5.1-8 gives more detailed stratigraphic information for areas within the site on. A detailed description of the rock units shown on this chart is included as Tables 2.5.1-1 ugh 2.5.1-7.

1.1.4 Regional Tectonics Northern Appalachians have been affected by four major orogenies: the Avalonian, Taconian, dian, and possibly the Alleghenian. The Avalonian and the Alleghenian orogenies mainly cted the southeastern portions of New England. The first three of these orogenies have duced a complex series of anticlinoria and synclinoria that constitute the New England land

s. The prominent structural belts are the Green Mountain anticlinorium, the Connecticut ey-Gaspe synclinorium, the Bronson Hill anticlinorium, the Merrimack synclinorium, and the kingham anticlinorium, all discussed in Section 2.5.1.1.2 and shown on Figure 2.5.1-6. These clinoria and synclinoria trend parallel to the Appalachian Mountain belt. Section 2.5.1.1.5 usses the geologic history.

etailed description of regional tectonics is included in this section, which forms the basis for subdivision of New England into tectonic provinces (Section 2.5.2.2).

1.1.4.1 Domes and Basins mentioned in Section 2.5.1.1.2, gneiss domes are present in the Connecticut Valley clinorium and the Bronson Hill anticlinorium.

se domes differ geologically because the gneiss cores of those in the synclinorium may consist ly of Precambrian basement from beneath the Paleozoic sequence, whereas, the core gneisses he anticlinorium seem to be intrusions into the pre-Silurian part of the rock sequence (Rodgers 0). The Lyme and Willimantic domes (Figure 2.5.1-5) lie east of the Bronson Hill

bron Gneiss, Brimfield Schist, Tatnic Hill Formation, and Quinebaug Formation) and have a cambrian-Cambrian core (Ivoryton Group, Plainfield Formation, and Sterling Plutonic Group) ndgren and Ebblin 1972).

most prominent basins in the region are the Triassic basins of the Connecticut Valley and w York-New Jersey and Pennsylvania areas, and the Carboniferous basins of southeastern New land (Figure 2.5.1-6). Offshore basins have been located by geophysical methods south of w England and in the Gulf of Maine (Section 2.5.1.1.2).

1.1.4.2 Faulting effects of the different stages of mountain building are widespread throughout New England.

varying types of faults present in different sections have allowed a reconstruction of the logic history and an increased understanding of the tectonic forces related to each orogeny.

racteristic crustal structures have been left by the Taconian and Acadian orogenies and later he rifting during the Triassic-Jurassic period.

area most affected by the Taconian orogeny is along the Hudson River from approximately bury, Vermont, to the vicinity of Poughkeepsie, New York, and eastward into western ssachusetts. The region exhibits a number of gravity slices that slid off an uplifted block to the during middle to late Ordovician time (Bird 1969).

umber of thrust faults are noticeable in New England. The Ammonoosuc fault in western New mpshire (Figure 2.5.1-6) trends N25E (Rodgers 1970) and dips at approximately 38 degrees to northwest. Silicified zones have been noted along the fault and the displacement has been mated to be 7,000 feet (Billings 1956). The fault offsets the metamorphic isograds associated h the Acadian orogeny: however, it is intruded by granitic rocks associated with the White untain magma series (Billings 1956). Potassium-argon studies on biotite from the Conway nite yield a radiometric age of 172 3 m.y.a. (Foland et al., 1971) indicating no movement g this fault since the granitic intrusion. Rodgers (1970) suggests that the Ammonoosuc may normal fault; however, Billings (1956) considers it a thrust fault.

ther major thrust fault system, the Lake Char-Honey Hill, lies in southern and eastern necticut. The Honey Hill, the east-west segment, extends from Chester near the Connecticut er eastward to south of Preston. The Lake Char section runs north-south from Lake Char in ssachusetts to Preston, Connecticut. The fault system is characterized by zones of cataclastic ks up to 2,500 feet thick (Dixon and Lundgren 1968). The plane of the fault is an irregular, ped surface. The dip of the Honey Hill section is generally at low angles to the north with a imum at 55 degrees in the Preston area; the Lake Char section dips westward at roximately 10 degrees (Dixon and Lundgren 1968). The Honey Hill part of the system is roximately 14 miles from the Millstone site.

thrust fault activity along the Lake Char-Honey Hill system is thought to have begun in the dle to late Devonian and continued into the Permian period (170-225 m.y.a.). Movement on

vement on the fault plane was toward the southeast (Dixon and Lundgren 1968). Dixon and dgren (1968) believe that movement associated with the Lake Char-Honey Hill system prised the last pre-Triassic activity in the area.

ently, Lundgren and Ebblin (1972) have hypothesized that the thick zones of cataclastic rock related to relative upward movement of basement at different places and at different times m late Devonian to Permian. This intense folding developed major cataclastic units in zones of h shear between mantling rock and basement complexes. Three different episodes of uplift ught about the present alignment of structure in southern Connecticut.

gers (1970) indicates that late movements occurred sometime after Carboniferous, but before late Triassic. The Honey Hill fault is cut by faulting believed to be related to Triassic rifting dgers 1970, Goldsmith 1967c).

ther to the northeast in Massachusetts is another large thrust fault system, the Clinton-wbury, paralleling the Bloody Bluff system. Skehan (1969, 1973), Castle et al. (1976), and on (1976) have suggested that the Clinton-Newbury - Bloody Bluff system is a continuation of Lake Char-Honey Hill system of Connecticut. The Clinton-Newbury -Bloody Bluff zones run heasterly from south of Worcester to Newburyport and into the Gulf of Maine (Skehan 1969).

ailed mapping linking the Lake Char to the Bloody Bluff has yet to be done. Exposures in the chusett-Marlboro tunnel indicate that these faults dip to the northwest and are reverse in nature ehan 1968). The average direction of tectonic transport is to the east, similar to that of the e Char-Honey Hill fault. The dominant faulting is later than the metamorphism and is bably late Paleozoic to mid-Mesozoic (Skehan 1968). A prominent number of northerly ding, younger, high-angle faults have been observed throughout the New England area, some ing the thrust faults associated with the Clinton-Newbury system.

northern border of the Triassic Newark Basin is bounded by a series of closely spaced parallel faults that commonly trend N30E to N50E and dip to the southeast. This Ramapo fault em has a complex history of movements dating back to late Precambrian (Ratcliffe 1971).

e Triassic rejuvenation of the old fracture system produced the Newark depositional basin.

mal faulting associated with the regional rifting and the deposition of the coarse glomerates in the basin continued into the Jurassic (Ratcliffe 1971). Page et al. (1968) have orted recent seismic activity in the vicinity of the Ramapo, but there has been no movement cted at the surface.

Triassic Connecticut Valley Basin extends from the Connecticut shore northward to the ssachusetts-Vermont border. The basin averages about 20 miles in width and exposes clastic mentary deposits interlayered with basalt flows and sills generally dipping to the east. At the ern edge, the deposits are abruptly ended by a west dipping normal fault zone. It has been erally accepted that the Connecticut portion of the basin was formed by faulting that was temporaneous with the deposition of the clastic sediments, and the fault zone of the east side gs into contact the Triassic sediments with the Paleozoic crystalline rocks to the east (Wheeler 9, Sanders 1960). The northern part of the Triassic Basin may have had a slightly different

hern portion of the basin has been established in the Mineral Hill area of Montague, ssachusetts (NUSCO. 1974). This fault has been interpreted as a thrust fault, which was later tivated with minor normal displacement. Potassium-argon radiometric dating of fault gouges nd along this fault and other small faults in the region yielded dates between 140 and 180

.a. (NUSCO. 1974). These dates reflect the movement related to the extension tectonics of the ssic-Triassic period.

umber of smaller faults are associated with the Carboniferous basins of eastern Massachusetts eastern Rhode Island. Some of these faults bound the basin. Many of the faults associated h the Boston Basin are thrust faults. These are smaller splays off the large Bloody Bluff fault em previously mentioned (Nelson 1976). These faults were originally formed during the pressional forces associated with the Acadian orogeny. Movement along the faults is believed e associated with the climax of the regional metamorphic event (Nelson 1976). Nelson (1976) cates that another near-surface fault system is post-Pennsylvanian in age, and that this system be related to the faulting of the Pennsylvanian rocks of Rhode Island.

eastern margin of the Woonsocket and North Scituate Basins is bounded by high angle faults inn and Oliver 1962). Although a short portion of the western boundary of the Narragansett in is a normal fault (Quinn 1971), silicification along this fault may indicate some association h Triassic activities (Rodgers 1970). Other small faults on the northeast edge of the ragansett Basin bring Pennsylvanian sedimentary rocks in contact with older plutonic rocks.

physical studies by Ballard and Uchupi (1975) indicate a number of basins in the Gulf of ne and the Georges Bank. These basins were postulated to be bounded by faults associated h the Triassic-Jurassic period. As shown on Figure 2.5.1-6, these authors suggest a boniferous basin extending offshore northeast of the Boston Basin. However, rock samples vered from these areas by Ballard and Uchupi (1975) fail to support the existence of these physically-inferred basins.

shore geophysical studies by McMaster (1971) indicate a fault occurring southwest of Block nd. Recent work performed by Weston Geophysical Engineers, Inc., for New England Power mpany (1976) and by the USGS (Needell and Lewis 1982) has indicated that this fault, named New Shoreham fault, lies slightly east and extends further northward then originally indicated McMaster (1971). It is a normal fault, striking approximately N30-50W and dipping at roximately 75 degrees to the northeast. The fault displaces sediments identified as Cretaceous; ever, Pleistocene deposits are undisturbed. The nearest approach of the New Shoreham fault pproximately 21 miles southeast of Millstone Point (Figure 2.5.1-6).

ny faults have recently been investigated throughout New England. These investigations cate that the last episode of movement was associated with Jurassic-Triassic tectonics. Lyons Snellenburg (1971) have investigated three normal faults in New Hampshire. The study uded the radiometric dating of the clay gouge generated during faulting. Radiometric testing ormed on the illite portion of the clay gouge yielded ages between 157 and 164 m.y.a.

4).

th-south trending high-angle faults have been analyzed in the Charlestown, Rhode Island area.

assium-argon test results on the illite clay gouge indicated dates ranging from 169 to 226

.a. (NEPCo. 1976).

h-angle, north-south trending normal faults uncovered in the excavation of Millstone 3 have been investigated (NNECO 1975, 1976, 1977) and are discussed in greater detail in tion 2.5.3.2. Radiometric age determinations on clay gouge indicate dates ranging from 109 to m.y.a.

h-angle normal faults are quite common in southern New England. Two of these faults, the tern Hill (Rodgers 1970) and the unnamed fault in the Uncasville quadrangle, (Goldsmith 7c), cut the Honey Hill fault. The unnamed fault in Uncasville (Goldsmith 1967c) dies out roximately 10.5 miles northeast of Millstone Point. These faults are believed to be related to rifting associated with the Trassic-Jurassic period because radiometric age dating indicates the last activity along some of these faults occurred in that period. Rodgers (1975), Skehan 75), and Goldsmith (1973) believe that the hydrothermal activity, typically silicification, along ts of this type represents the youngest known tectonically related event in southern New land.

1.1.4.3 Tectonic Summary structural pattern of New England (Figure 2.5.1-6) is characterized by strong north-northeast ds. The major anticlinoria and synclinoria, the alignment of domes and basins, the trend of the ting, and the alignment of most of the granitic intrusions indicate a constant and pervasive onic force acting in the same orientation for a prolonged period of time.

ny of the features are the result of compressional forces acting throughout the region during ch of the Paleozoic era. The area has undergone folding, igneous intrusion, refolding, and sequently, thrust faulting.

Mesozoic era was characterized by faulting and igneous activity differing from that of the ozoic era. Normal faulting associated with extensional forces is well developed in the thern New England area. The intrusion of diabase dikes and sills is also associated can be erved, physiographic and tonal. Tonal linear features may be due to a change in vegetation, reas physiographic lineaments generally are due to topographic expression accentuated by ion. These features are probably related to structural discontinuities, chiefly faults, shear es, and joints (O'Leary et al., 1976).

1.1.4.4 Remote Sensing d Satellite (LANDSAT) photographs of Connecticut, Rhode Island, southern Massachusetts, eastern New York were studied to identify linear features or lineaments. A lineament is

umably reflects a subsurface phenomenon (O'Leary et al., 1976). Two types of lineaments can bserved, physiographic and tonal. Tonal linear features may be due to a change in vegetation, reas physiographic lineaments generally are due to topographic expression accentuated by ion. These features are probably related to structural discontinuities, chiefly faults, shear es, and joints (O'Leary et al., 1976).

ure 2.5.1-9 shows the LANDSAT photographs used for the study, and Figure 2.5.1-10 shows lineaments greater than 10 miles long identified on the photographs. The explanation for the ations shown on Figure 2.5.1-10 are given in Table 2.5.1-8. The linear features shown on ure 2.5.1-10 are grouped into three categories:

1. Those coinciding with mapped faults

2. Those coinciding with mapped geologic contacts

3. Those which are not identifiable with either of the above, but associated with topographic expression lineaments shown on Figure 2.5.1-10 are, for the most part, due to differences in topography.

se differences may be due entirely to the resistance to erosion of the varying rock units. The ority of the lineaments coincide with geologic contacts which have been accentuated by the ion of rivers and streams. As can be seen on Figure 2.5.1-10 and listed in Table 2.5.1-8, es of weakness within rock masses have also accounted for a number of the lineaments.

ional joint patterns and mapped faults are easily identifiable on the LANDSAT photographs.

se often correspond to topographic lows due to the erosion of the broken and more easily thered material.

1.1.4.5 Structural Significance of Geophysical Studies physical studies have aided in the interpretation of the geology of New England. The magnetic and Bouguer gravity maps relating to regional geologic features are presented on ures 2.5.1-11 and 2.5.1-12, respectively.

aeromagnetic information shown on Figure 2.5.1-11 generally conforms to the regional logic trends observed in New England.

umber of areas exhibit strong alignment or high intensity of magnetic character. The Lake r-Honey Hill system in Connecticut and the Clinton-Newbury fault zone in Massachusetts are most prominent lineations on the aeromagnetic map. The Cape Ann area, north of Boston, is racterized by its high magnetic intensity. This is caused by the combination of the high nsities related to the basic rock of the Salem Gabbrodiorite and the existence of a highly ted and brecciated zone. The northwestern and southern boundaries of the Cape Ann area ely coincide with the Clinton-Newbury, the Bloody Bluff, and the Boston border faults

aller, less striking anomalies occur in the site area, in the Cape Cod area, and in central ssachusetts just east of the Connecticut River Valley Triassic Basin. The anomaly in the lstone area follows the folded pattern of the interlayed metasedimentary and metavolcanic ks. The rock with very high susceptibilities apparently wraps around the structural features cent to the site (Lyme dome, Figures 2.5.1-13 and 2.5.1-14) and extends out into Long Island nd (Barosh and Pease 1974). The anomalies on Cape Cod are probably due to large basic usive bodies (Barosh et al., 1974). The north-south trending anomaly east of the Triassic Basin entral Massachusetts is related to the presence of metavolcanic rocks of high magnetic eptibility. Barosh and Pease (1974) indicate that the metavolcanic rocks to the south are less netically susceptible due to the effects of retrograde metamorphism and they are not noted on aeromagnetic map.

all isolated anomalies can be observed on the east side of the axis of the Green Mountain clinorium. A series of ultramafic bodies extending from Canada southward to Massachusetts ehan 1961) may be the cause of these anomalies.

ure 2.5.1-12 shows the regional gravity in relation to the geologic structures of New England the trend of the gravity anomalies corresponding to the differing structural alignment. The t prominent anomaly is along the axis of the Green Mountain anticlinorium. This gravity high ears to be caused by the relative uplift of a dense lower crust (Kane et al., 1972). In the eastern ion of New England, it is still apparent that the gravity anomalies follow the structural trend.

s trend is sharply broken by the large negative anomaly encompassing the White Mountains of w Hampshire. Other locally pronounced anomalies are found throughout New England and for the most part, associated with igneous masses. The large anomaly on Cape Ann is bably due to mafic rock underlying the Cape Ann series.

1.1.5 Regional Geologic History Regional Geologic Map (Figure 2.5.1-4) shows the distribution and generalized age tionships of rocks in the New England area.

geologic history of New England is complex because the region has been subject to several genies during the Precambrian and Paleozoic eras. The early and middle Paleozoic rocks esent geosynclinal sequences which have been deformed and recrystalized to varying degrees ng the disturbances discussed below.

nger, relatively unchanged rocks are found in the Carboniferous basins in southeastern New land and in the Triassic-Jurassic basins in south-central New England and New Jersey-nsylvania.

youngest igneous activity in New England took place in the Mesozoic Era. The passive lacement of the White Mountain series during the Jurassic and Cretaceous periods, and the

Precambrian erences have been recognized between the Precambrian rocks in the western part of New land and those of eastern New England. Basement rocks of western New England belong to Grenville province. The older Precambrian rocks in this province include those in the core of Adirondack Mountains and those of the Green Mountain, Berkshire, Housatonic, and Hudson hlands massifs (Figure 2.5.1-6). Isachsen (1964) considers the Manhattan Prong to be cambrian and is considered by Naylor (1975) to be part of the western basement. These rocks characterized by high temperature, high pressure (granulite facies) metamorphism at 1,100 to 0 m.y.a. and may include units that formed significantly earlier (Naylor 1976). Rodgers 68a) suggests that the eastern edge of the North American continent during the Cambrian and ly Ordovician periods coincided with the eastern edge of these massifs.

cambrian rocks of eastern New England are believed to be associated with the Avalonian geny (Rodgers 1972). At Hoppin Hill, Massachusetts, the Dedham Granodiorite is onformably overlain by lower Cambrian slate that is lithologically similar to sequences in wfoundland (Skehan 1968). The eastern basement is considered to be a thick sequence of dominantly mafic volcanic rocks with intercalated metasedimentary rocks and granitic to broic plutons lying underneath fossiliferous lower and middle Cambrian strata (Naylor 1976).

idium-strontium (Rb-Sr) whole-rock ages for the Hoppin Hill Granite, Northbridge and ford Granite, and the Dedham Granodiorite date from 514 to 591 m.y.a. (Fairbairn et al.,

7). The eastern basement is nowhere characterized by granulite facies metamorphism and has yielded zircon or rubidium-strontium whole-rock ages greater than 650 m.y.a. This basement esents a period of widespread volcanism and plutonism with peak activity between 600 and m.y.a. (Naylor 1975). The eastern basement lies, for the most part, east of the Lake Char-ton Newbury fault system. Naylor (1976) considers the gneisses along the southeastern coast onnecticut to be part of the eastern basement and not an eastward extension of the Bronson sequence. The Millstone site lies in this sequence and it is discussed in greater detail in tion 2.5.1.2. Late Precambrian through early Devonian stratified sequences occupy most of area between the eastern and western basements (Naylor 1975).

Early Paleozoic o bands of Cambrian rocks are observed in New England; one along the Hudson and mplain Valleys extending northward to Quebec, and the other in scattered outcrops along the ent-day coast (Theokritoff 1968). The western band was a sand-carbonate shelf sloping ply eastward and grading into a basin of mud deposition. The eastern band consists mainly of d deposits around nonvolcanic islands. During early and middle Cambrian, Pacific province nas occupied sites on the shelf and adjacent parts of the basin, whereas Acado-Baltic faunas upied sites around the island chains (Theokritoff 1968).

imentation continued into the Ordovician period. In early middle Ordovician, much of both platform carbonates and terrain to the east were folded and became emergent (Berry 1968).

masses to the east, and the deposition of deltaic sediments westward from these lands (Berry 8). The uplifts were the surface effects of the orogenic deformation at depth accompanied by

-grade metamorphism (Rodgers 1970). Also associated with these events, referred to as the onian orogeny, was the intrusion of plutons related to the Highlandcroft magma series (Berry 8). During much of middle Ordovician time, a series of volcanoes and islands existed along present day Bronson Hill anticlinorium. Much of eastern Connecticut is underlain by asedimentary, metavolcanic, and plutonic rocks related to this volcanic-island chain.

ivity related to the Taconian orogeny occurred as a discontinuous series of disturbances ween 450 to 500 m.y.a. with the area of maximum deformation located in western New land (Rodgers 1970).

Middle Paleozoic ing the Silurian period, those areas uplifted by the Taconian orogeny were gradually roached upon and eventually covered (Boucot 1968). Volcanic rocks continued to be deposited g the Bronson Hill anticlinorium and volcanic activity became apparent along the Avalonian from southern New Brunswick through southeastern Maine to eastern Massachusetts dgers 1970). A belt coinciding with the present-day Merrimack synclinorium was the locus of thickest sequence of Silurian sediment in the New England region (Boucot 1968).

ywackes and thick argillaceous sandstones characterize this sequence.

bonate sequences reached a maximum in the earliest part of the Devonian period in western w England (Rodgers 1970, Boucot 1968). Clastic material was deposited upon this calcareous uence as the land mass to the east expanded westward (Boucot 1968).

middle Devonian, deposition had ceased throughout the region and the area then underwent its t severe deformation, metamorphism, and granitic intrusions (Rodgers 1970). The Acadian geny is responsible for most of the folding in the rocks presently exposed through the region.

belt of maximum intensity of this activity extends southward from central Newfoundland to ern Connecticut (Rodgers 1970). Faulting related to the Acadian Orogeny is widespread ughout the region. Disturbance of the regional metamorphic isograds indicates that folding faulting continued after the peak of metamorphism (Thompson et al., 1968).

Late Paleozoic deposition of material from this period is concentrated in the southeastern part of the region.

Boston Basin of eastern Massachusetts and the Narragansett, Norfolk, Woonsocket, and uate Basins of Rhode Island and southeastern Massachusetts are the only remnants of mentation. Rocks in these basins consist generally of coarse clastic sediments of continental in. The basins are controlled by faulting; the Boston Basin by high-angle reverse faulting lson 1976) and the Narragansett by high-angle normal faulting (Weston Observatory 1976).

amorphism has only slightly affected the Boston Basin, whereas the Narragansett Basin has,

ormation during the late Paleozoic is not widespread throughout New England. The eghenian orogeny has affected some areas of southern New England. The major manifestation his orogeny is the granitic intrusion in southern Rhode Island and Connecticut. The gentle ing and the metamorphism of the Narragansett Basin sediments may also be attributed to the ghenian orogeny. Activity along the region's extensive system of thrust faults may have tinued into the Permian period. A thermal disturbance yielding K-Ar dates of 230 to 260

.a. has been observed in an area 60 to 80 miles wide extending northward from the southern necticut coast to southwestern Maine, the cause of which is still unknown (Zartman et al.,

0). The igneous activity in Rhode Island and Connecticut may account for the southern extent; ever, Permian granitic intrusions are not observed further north. Granitic and pegmatitic usions related to the Westerly Granite intrude the Monson Gneiss at the Millstone site.

assium-argon dating (NNECO. 1975) also indicates that the Monson Gneiss at the site has n affected by the thermal disturbance described by Zartman et al. (1970) (Section 2.5.1.2).

Mesozoic and Cenozoic ard the end of the Triassic period, a series of linear, generally fault-bounded troughs formed which continental clastic sediments and volcanics accumulated. Two of these basins are arent in this region: the Connecticut Valley Triassic Basin and the Newark-Delaware Basin ure 2.5.1-9). Similar basins beneath and beyond the continental shelf off the eastern and thern coasts of New England have been inferred by geophysical studies (Sheridan 1974, lard and Uchupi 1972 and 1975, Mayhew 1974). Dikes of Triassic-Jurassic age are common ughout the region. High-angle faulting related to the rifting is also widespread throughout thern New England (Section 2.5.1.1.4.2).

eous activity in the region continued with the intrusion of the White Mountain onic-volcanic series. These rocks are found from northern to southeastern New Hampshire, thern Maine, and east central Vermont. Age determinations indicate that activity associated h the White Mountain series began in the Triassic and continued into the early Cretaceous od, 216 to 112 m.y.a. (Foland et al., 1971, Armstrong and Stump 1971). This plutonism-anism represents the last known localized tectonic activity that has occurred in the region of site. Further north, igneous activity continued with the intrusion of the Monteregian Hills onic rocks. The latest activity associated with the Monteregian Hills is approximately 100

.a. (NUSCO. 1974).

Appalachian Mountains have apparently undergone continuous erosion since late Paleozoic ept in the areas of down-dropped Triassic fault blocks (Rodgers 1967). After Jurassic eplanation of the Piedmont Plateau and what presently underlies the Coastal Plain, a broad parallel to the coast was submerged. Material eroded from the exposed Piedmont was osited in the coastal area in the form of a seaward thickening wedge. This wedge is inantly Cretaceous in age (Figures 2.5.1-2 and 2.5.1-5), but includes some thin deposits of iary age.

ept in detail, were similar to those of today (Flint 1975). The ice scoured the land leaving tered deposits throughout the area and advancing to and beyond the southern New England st. Glacial deposits are the sole rock type exposed on eastern Long Island, Cape Cod, and tucket. The ice began to retreat from the Connecticut coast approximately 15,000 years ago nt 1975). Temporary advances and retreats of the front of the glacier caused deposits of end aines prominent throughout southern Connecticut and Rhode Island (Flint 1975). Pleistocene osition on the submerged Coastal Plain is dominated by a complex series of sedimentary uences separated by unconformities. These relationships are the result of fluvial and marine cesses active during regressions and transgressions of the sea (Knott and Hoskins 1968).

1.2 SITE GEOLOGY Millstone site is located at the southern tip of Millstone Point in Waterford, Connecticut. The is a low lying peninsula within the Seaboard Lowland section of the New England siographic province. Its physiography is discussed in Section 2.5.1.2.1.

Millstone area, like the rest of New England, was covered with glacial ice until roximately 15,000 years ago. The glaciers deposited a thick layer of glacial till and, as they ded, left end moraine and outwash deposits. The surficial geology of the area surrounding the lstone site is shown on Figure 2.5.1-3.

bedrock geology is characterized by extensive deformation, metamorphism, and intrusion by ous bodies. The bedrock geology of the 5-mile radius is shown on Figure 2.5.1-13.

geology of the eastern portion of Connecticut is made difficult to decipher by the complex ing and faulting of the Late Paleozoic era. The tectonic features of the eastern section of necticut are shown on Figure 2.5.1-14. As shown on this figure, the Millstone site lies roximately 30 miles east of the Triassic Border fault, and approximately 15 miles south of the ey Hill fault. The area south of the Honey Hill fault is complexly folded. The site lies on the limb of the recumbent Hunts Brook syncline which mantles the Lyme dome. The site location h relation to these structures is shown on Figure 2.5.1-14.

1.2.1 Site Physiography Seaboard Lowland section of the New England physiographic province narrows along the necticut coast, as shown by Figure 2.5.1-1. In the Millstone Point area, this section narrows pproximately 15 miles, bordered on the north by the New England Upland section and just th of the site by the Coastal Plain physiographic province.

most striking topographic expression in the area is the north-south trending ridges and eys. The area is drained by a number of brooks and also the Thames, Niantic, and the necticut Rivers, the latter approximately 8 miles west of the site.

ptured, by weathering and rainwater runoff, essentially to its surface existing before glaciation urred (Flint 1975). End moraine and glacial stream deposits are also prevalent throughout the on (Figure 2.5.1-3).

Millstone site is located on a small peninsula near the mouth of the Niantic River. Wave on has eroded the blanket of till from the promontories of Millstone Point, exposing rock. The orked material was deposited as beach sand in the protected areas. Eolian deposits are found ome locations, and tidal marshes and swampy areas are common.

ch of the plant area has been graded and backfilled during the construction of the three units of power generating facilities now at Millstone Point.

re is no physiographic evidence indicative of actual or potential localized subsidence, mass ting, or landslides in the vicinity of the site.

1.2.2 Local Stratigraphy site surficial and site bedrock maps are shown as Figures 2.5.1-3 and 2.5.1-13, respectively.

se maps cover approximately the area within the 5-mile radius of the site. The age tionships and descriptions of the differing bedrock units found within this region are shown on ure 2.5.1-13.

site is underlain by the Monson gneiss of pre-Silurian age and the Westerly Granite of nsylvanian or younger age. The bedrock units shown on Figure 2.5.1-13 are dominated by asedimentary and metavolcanic rocks of Cambrian or possibly Precambrian or Ordovician

. The metasedimentary and metavolcanic units have been intruded by several granitic masses, which the Sterling Plutonic Group is the oldest. The granitic gneisses seem to have been laced at fairly deep levels in the crust, for they are associated with migmatites and are mately intermingled with, and grade into, some associated metasedimentary and metavolcanic isses (Goldsmith and Dixon 1968). The Sterling gneiss units have not been noted tigraphically above the Monson gneiss in the site area. The younger granitic intrusions are the ular granites located in the Lyme dome and the Westerly Granite located along the coastline.

se granites are believed to be Permian in age (Goldsmith 1967b).

distribution of Quaternary surficial material is shown on Figure 2.5.1-3. This material udes such glacial deposits as glacial till, end moraine deposits, and stream deposits. Younger mp, littoral, alluvial, and eolian deposits also occur.

1.2.3 Site Stratigraphy excavation for Millstone 3 has been extensively mapped. These maps are shown and cribed in Section 2.5.4.1. In the site area, the bedrock surface is very irregular and completely ered with glacial till. Construction activities from Millstone 1 and 2 disturbed the naturally osited material in the site area which, for the most part, was replaced with artificial fill.

ioclase (45 percent), quartz (35 percent), and biotite (15 percent). Sericite, garnet, apatite, ote-clinozoisite, and zircon are also present (NNECo. 1975). The Monson gneiss is medium-ned, light gray with strong biotite foliation. A number of biotite segregation bands were erved throughout the excavation (Section 2.5.4).

Monson gneiss is intruded by pegmatite and granite sills related to the Westerly Granite ch was quarried on Millstone Point until 1960. The distinction between a granitic and a matitic intrusion is a subtle one. Both intrusions are related to the same source and variable n sizes are inherent in each. The Westerly Granite is considered to be a dike rock consisting of y to pink, fine-to-medium-grained, equigranular granite composed of oligoclase, microcline, quartz. The pegmatitic intrusions are similar in composition to the Westerly Granite usions except for their coarser grain size. Biotite, muscovite, and accessory minerals are also ent in smaller percentages (Goldsmith 1967b, Lundgren 1967).

entire bedrock surface at Millstone is covered by a layer of glacial till consisting of both basal ablation tills. The basal till is a dense, unsorted soil material plastered and compacted into e by the weight and dynamic pressure of an actively moving glacier. The ablation till was osited as the ice retreated. It is generally an unsorted material and, because it was subjected to ghter load than the basal till, it is less dense.

basal till consists of a mixture of cobble and boulder size rock fragments, gravel size erial, sand, and some silt binder. The ablation till is irregularly stratified with lenses of sand gravel and mixtures of cobbles, gravel, sand, and silts.

cial stream deposits are also present on Millstone Point (Figure 2.5.1-3), for the most part sisting of stratified sands with some silts and gravel.

nger beach, swamp, and marsh deposits are also observed in the site area (Figure 2.5.1-3).

beach deposits are chiefly well sorted sand and pebbly gravel deposited by current and wave on.

1.2.4 Local Structural Geology Millstone site lies on the southeastern coast of Connecticut. The regional tectonic map ure 2.5.1-6) shows the location of the site with respect to the major structural features of New land. Figure 2.5.1-14 illustrates the generalized tectonic elements of eastern Connecticut and ure 2.5.1-13 shows the structure within the 5-mile radius.

tectonic map of eastern Connecticut (Figure 2.5.1-14) shows the major folds and faults that e affected the region. Three orogenies (Taconian, Acadian, Alleghenian) have structurally left r imprint on a series of complexly deformed rocks. As shown by the site bedrock geology map ure 2.5.1-13), the Lyme dome, Hunts Brook syncline, and two smaller anticlines lie within site area. The larger structural features, such as the Bronson Hill anticlinorium, the Merrimack

structural trend south of Honey Hill is generally east-west, whereas, in the remaining portions he state, the structural trends are north-south, paralleling the regional trend.

north-south and east-west structures tend to meet in the Killingworth dome. This is not a ple dome and must have reached its present form and acquired its complicated internal cture in several stages (Lundgren and Thurrell 1973). Recumbent isoclinal folds are common ughout and the dome itself may consist of a series of antiforms and synforms.

Lyme dome, east of the Killingworth dome (Figure 2.5.1-14), also appears to be a simple clinal structure; however, the dome is mantled by the folded isoclinal Hunts Brooks syncline.

extent of the dome is marked by the contact between the Mamacoke Formation, Monson iss, or the Brimfield schist with the Plainfield Formation (Figure 2.5.1-13). The broad internal cture of the dome is indicated by the pattern of the middle unit of the Plainfield Formation and alaskite units (Sterling Plutonic Group) and by the foliation pattern (Lundgren 1967).

tribution of the stratigraphic units indicates that the dome is a northward plunging anticline.

Lyme dome lies just west of the Millstone site (Figure 2.5.1-13).

Selden Neck dome, which parallels the Honey Hill fault, is the last major dome south of the

t. This dome is essentially an overturned, possibly recumbent, anticline having a folded axial ace that dips north or northwest (Lundgren 1966).

Hunts Brook syncline, which separates the Selden Neck dome from the Lyme dome, is the prominent fold south of the Honey Hill fault. The isoclinal syncline bends around the Lyme e and the trace of the axial plane lies within the belt of the Brimfield schist and the Tatnic Hill mation. The axial plane of the Hunts Brook syncline dips away from the Lyme dome; in the lstone area, the syncline dips to the east with the site lying on the overturned limb.

Hunts Brook syncline meets the Chester syncline in the Killingworth dome area. Lundgren

66) has proposed two theories concerning the relationship between these two synclines. If the ts Brook syncline is a folded overturned syncline with a nearly horizontal axis, then this axis bably meets the axis of the Chester syncline at a right angle, implying that the Hunts Brook med after or during the development of the recumbent Chester syncline. However, if the Hunts ok syncline plunges steeply to the northwest, then it could merge with the Chester syncline eath the Selden Neck dome (Lundgren 1966).

Chester syncline is a recumbent isoclinal syncline trending north from the Killingworth dome on and exhibiting a complexly folded axial plane which parallels the Monson anticline until it hes a point north of the Honey Hill fault which it parallels for some distance (Figure 2.5.1-o smaller anticlines are shown on Figure 2.5.1-13. Both are overturned isoclinal anticlines h their axial planes dipping to the northwest. The area is complexly folded and it appears that two anticlines may actually be one.

Honey Hill fault (Section 2.5.1.1.4.2) lies approximately 15 miles north of the Millstone site.

closest mapped fault is approximately 10 miles northeast of the site in the Uncasville drangle (Figure 2.5.1-14). This fault trends north-south and is believed by Goldsmith (1973) e a normal fault related to Triassic tectonics. The amount of displacement is unknown, but it is wn to cut the Honey Hill fault (Goldsmith 1967c). This faulting is thought to be related to the tern Hill fault further to the east due to its similar attitude. The Triassic Border fault lies roximately 30 miles west of the site (Figure 2.5.1-14).

umber of faults have been uncovered during the construction of Millstone 3 and are discussed etail in Section 2.5.3.2.

1.2.4.1 Site Structural Geology Millstone site lies on the overturned eastern limb of the Hunts Brook syncline (Figure 2.5.1-The axial plane of the syncline in the site area dips to the east as shown on Section A-A of ure 2.5.1-13. Detailed mapping of the excavation has yielded much information on the logy of Millstone Point (Sections 2.5.3.2 and 2.5.4.1).

site is founded for the most part on the Monson gneiss which is part of a series of lower eozoic metavolcanic and metasedimentary rocks and granitic gneisses that underlie most of ern Connecticut (Goldsmith and Dixon 1968). The Monson gneiss at the site area is light gray, ium grained, thinly layered with light feldspathic and dark biotite and hornblendic layers ldsmith 1976b). It consists of plagioglase (45 percent), quartz (35 percent), and biotite (15 ent) with accessories of garnet, apatite, epidote-clinozoisite, and zircon (NNECo. 1975). The ation is a well defined alignment of biotite flakes. Figure 2.5.1-15 is a lower hemisphere plot wing the foliation readings taken from final grade mapping. The average foliation attitude for points is N67W, 48NE. Segregation bands of biotite are apparent throughout the site.

Monson gneiss has been intruded by a series of pegmatite and granite bodies. For the most

, these granitic intrusions are parallel to the foliation and believed to be related to the injection the Westerly Granite (Goldsmith 1967b), which is a prominent intrusion throughout theastern Connecticut and Rhode Island (Goldsmith 1967b).

ting is well developed at the site with the major joint set striking N03W and dipping 63NE.

ure 2.5.1-16 gives a contour diagram of poles to joint planes for the joints observed while ping final grade. Minor joint sets have attitudes of N02W, 78SW; N69E, 74SE; and N48W, E. The joints generally exhibit smooth, planar surfaces with a majority having a coating of rite and some showing iron oxide staining. Jointing at the site is discussed further in tion 2.5.3.2.3. Slickensides were found in 241 locations. Figure 2.5.1-17 gives the contour of these data. The points are concentrated along the east-west axis, indicating that the major ction of displacement is east-west. The points also indicate the association of the slickensides h high angle planes, thus implying a minor readjustment of dip-slip type.

d northerly and dip at high angles east or west. The other fault is a minor low angle thrust.

ure 2.5.1-18 shows the location of these faults. The faults are all incapable features with the activity occurring approximately 142 m.y.a. Slickenside information and a section through t 18 in the Millstone 2 and 3 condensate polishing facilities indicate that the faulting is of the mal type, with some oblique dip-slip movement.

1.2.5 Site Geological History geological history of southeastern Connecticut is obscured by the complex folding and amorphism that the area has undergone. The Taconian, Acadian, and Alleghenian orogenies e affected the area to a varying extent (Goldsmith and Dixon 1968).

ages of the rocks present in the site area are still in doubt. The Monson gneiss, the New don gneiss, the Mamacoke Formation, and the Plainfield Formation are pre-Silurian in age, most probably the rocks range in age from late Precambrian or Cambrian to Ordovician, ldsmith 1976). The Brimfield schist, which lies unconformably beneath the Bolton Group, is ilar to and can be traced into the Partridge Formation and the Ammonoosuc volcanics of dle Ordovician age (Goldsmith and Dixon 1968). Two major plutonic rocks are present in the area, the Sterling Plutonic Group and the Westerly Granite. The older Sterling Plutonic Group elieved to be Cambrian or older in southern Connecticut and does not occur stratigraphically ve the Monson Gneiss around Millstone Point (Goldsmith and Dixon 1968). However, the ling Group is younger that the Monson gneiss, so the Sterling may be Ordovician or younger.

youngest rock type present in the site area is the Westerly Granite, which is regarded as mian (Lundgren 1967). A granitic intrusion other than the Sterling Plutonic Group or Westerly nite occurs in the Lyme dome. This nodular granite is believed to be older than the Westerly nite and younger than the granitic intrusions of the Sterling Plutonic Group (Goldsmith 7b).

relationship of the rocks within the site area is shown on the stratigraphic chart for the ounding area (Figure 2.5.1-7) and described in Tables 2.5.1-1 through 2.5.1-7. Figure 2.5.1-hows the distribution of the bedrock units.

origin of the oldest rocks found in the site area, the Plainfield and the Mamacoke Formations, bscure. These probably were originally quartz sandstone, limestone and dolostone, and shale ndgren 1966). The age of these rocks is still questioned, although it is believed that the rocks of Cambrian age (Page 1976). The remaining rocks in the site region with the exception of the ular and Westerly Granites are probably Ordovician in age.

Monson and New London gneisses are believed to be metamorphosed andesitic and dacitic anics and associated intrusions (Lundgren 1967). As mentioned in Section 2.5.1.1.5, the ent day Bronson Hill anticlinorium was the location of a series of volcanoes and islands ch served as a source area for much of the middle Ordovician period.

contiguous granitic gneisses in southern Connecticut suggest a Cambrian or older age ldsmith and Dixon 1968). However, the Monson gneiss, outside of the site area, has been d as 472 m.y.a. 15 (Brookins and Hurley 1965) and radiometric work by Zartman et al.

65) implies that the Quinebaug Formation, correlated with the Monson, is middle Ordovician.

Sterling gneisses seem to have been emplaced at fairly deep levels in the crust, for they are ciated with migmatites and are intimately intermingled with and grade into some associated asedimentary and metavolcanic gneisses (Goldsmith and Dixon 1968). The Sterling Plutonic up is widespread in Rhode Island, underlying most of the central portion of the state and sidered to be late Precambrian or Cambrian in age.

s, the age relations are problematic and have not been resolved to date.

Brimfield schist consisted originally of shale imbedded with minor amounts of quartz, dstone, limestone, andesitic and basaltic pyroclastics, and manganese-bearing chert. The osition of this pelitic unit represents a major change in the character of sedimentation, as anic rocks are of subordinate importance in the section above the base of the Brimfield and nic Hill Formations (Lundgren 1964). The Brimfield and Tatnic Hill Formations may have n deposited as geographically separate facies of a single stratigraphic unit (Lundgren 1964).

Brimfield schist is the youngest pre-Pennsylvanian rock found within the site area.

ch of the deformation that occurred in the Millstone area has been attributed to the Acadian geny, which affected much of central and eastern New England. The initial stages in the mation of the complex structure now observed are the north-south trending recumbent isoclinal s (Monson anticline and Chester syncline) which were formed in response to an east-west pression during early stages of post-Silurian metamorphism (Figure 2.5.1-14) (Lundgren 4). Deformations continued with the development of the east-west trending anticlines and clines, the Selden Neck dome and Hunts Brook syncline, respectively. Most of the major ures of the map pattern in the rocks south of the Honey Hill fault are the combined result of formation of the Lyme dome and the antiform at Chester. This uplift deformed the Hunts ok syncline, the Selden Neck dome, and the Honey Hill fault, resulting in the present ctural configuration.

amorphism accompanied the structural development mentioned above. Metamorphism of all rocks produced assemblages characteristic of the upper amphibolite facies (Lundgren 1966).

dgren (1964) believes the metamorphism took place when the rocks were deeply buried, bably at depths of 15 to 20 kilometers where the temperature was 550 to 650C.

amorphism presumably began during the Devonian period but may have continued into the mian (Lundgren 1963).

Honey Hill faulting also was initiated during the Acadian orogeny as part of the eastward lacement of the recumbent Chester syncline. Movement along the Honey Hill fault is believed e southeasterly, continuing beyond the period of peak metamorphism (Dixon and Lundgren 8).

ng the folding and uplifts of the Acadian orogeny. Movement along the Honey Hill fault may e continued into the Permian period.

owing the highly active Acadian orogeny was a milder period of gentle folding, granitic usion, and localized thermal activity. The Alleghenian orogeny affected only the southeastern ion of New England, mainly Rhode Island and southeastern Connecticut. The main ifestation of the Alleghenian orogeny was the intrusion of the Narragansett Pier Granite and Westerly Granite. The Pennsylvanian sediments of the Narragansett Basin of Rhode Island ibit folding associated with this orogeny. The thermal activity is exhibited by a narrow band nding from southern Connecticut to southwestern Maine. These rocks yield potassium-argon s of 230 to 260 m.y.a. The actual cause of this disturbance is still questioned although it could attributed to contact metamorphism related to contemporaneous igneous activity, alteration ciated with major faulting, regional metamorphism in late Paleozoic time, or burial followed plift and erosion (Zartman et al., 1970).

Millstone site has been affected by thermal disturbance and granitic intrusion. Granitic usions parallel to the foliation of the Monson gneiss, folded and overturned during the dian orogeny, are widespread throughout the site area.

assium-argon dating of biotite from the gneiss and the granitic intrusions at the site yielded a ge of ages from 208 to 273 m.y.a. (NNECo. 1975). At Millstone Point, the thermal disturbance ld be attributed to contact metamorphism during emplacement of the Westerly Granite.

most recently known expression of tectonic activity in the local area is faulting related to ssic-Jurassic rifting. Small high angle faults and joints associated with the larger Triassic ts of the Triassic Basin (Figure 2.5.1-14) are common in the Clinton quadrangle to the west ndgren and Thurrell 1973) and in the Moodus and Colchester quadrangles to the north ndgren et al., 1971). Goldsmith (1967a) shows two small high-angle faults in the Uncasville drangle northeast of the site, which he believes to be related to the Triassic-Jurassic tectonics ldsmith 1973). No faults are shown adjacent to the site on the quadrangle maps. In the process mapping the excavation at the Millstone site, eleven fault zones were uncovered ction 2.5.3.2). Potassium-argon dating of clay gouge from some of these fault zones indicates the last activity along these zones occurred about 142 m.y.a. Also associated with the ssic-Jurassic periods are the deposits of arkosic clastic sediments in the Connecticut Basin, usive igneous activity, and related injection of basic dikes throughout southern New England.

rothermal activity, typically silicification, is commonly found along faults related to the ssic-Jurassic tectonics. Rodgers (1975), Skehan (1975), and Goldsmith (1973) believe that the rothermal activity represents the youngest known tectonically related event in southern New land.

ent study of dikes in southwestern Rhode Island and eastern Connecticut indicates that a few prophyre dikes may be as young as Cretaceous. Their relation to hydrothermal activity is not wn.

es, and hills, similar to those of today (Flint 1975). Cretaceous and Tertiary sediments are ent south of the site (Figure 2.5.1-2). The northernmost previous extent of these deposits is nown. During Tertiary and Quaternary time, alternating periods of transgression and ession occurred along the coast of southern New England. The two major regressions took e during the Oligocene epoch and during the Pleistocene glaciation (Garrison 1970).

dence from outside the site area indicates that during the last million years or more, necticut was covered by continental glaciers at least twice, and possibly several times, ever, evidence of only one glaciation is found locally (Flint 1975). The ice at its maximum hed its outer limit along a line on, or south of, what is now Long Island and culminated roximately 18,000 years ago (Flint 1975). Pollen studies and radiocarbon dates on samples n in New London show that glaciation took place more than 13,000 years ago (Goldsmith 0, 1962a). Caldwell (Appendix 2.5A), after visiting the Millstone site, indicated that the last osition of till was approximately 18,000 years ago and that ice covered the area until about 00 years ago. The cumulative effect of the glaciation was to smooth, round off, and widen e of the valleys and to remove most of the pre-existing regolith (Flint 1975).

Millstone area is covered with glacial till, end moraine deposits, and outwash sands as shown Figure 2.5.1-3. The end moraines are common across Rhode Island and southern Connecticut.

y were deposited when the recession of the glacial margin slowed or stopped for some period nt 1975).

avations along the discharge tunnel uncovered slumped and faulted ablation till and outwash osits. These features were found to be quite common in the outwash and are believed to be ted to penecontemporaneous soft sediment deformations, in some cases associated with ting out of buried ice blocks (NNECO. 1982).

ce the glacial period, the surficial geology has been most drastically changed by the rise in sea l, which reworked the glacial outwash and eroded till and rock promontories, then depositing material on the beach to be reworked by the wind to form dunes.

1.2.6 Site Engineering Geology Category I structures at Millstone 3 are founded on rock, dense basal till, or compacted nular backfill. The properties of the subsurface materials are given in Section 2.5.4.2.

country rock at the site is the Monson gneiss. This gneiss exhibits a well-developed foliation to the alignment of biotite flakes. Segregation bands of biotite were also uncovered at the site.

ure 2.5.1-15 shows that the attitude of the foliation is quite consistent at N67E, 48NE. Jointing he site is also very well-developed. The contour plot of the Lower Hemisphere projection ure 2.5.1-16) indicates one major joint set with three minor sets. The most prominent set has verage attitude of N03W, 63NE. The minor sets have attitudes of N02W, 78SW; N69E, 74SE; N48W 07NE.

geology of the excavation is also described in Section 2.5.4.1. Maps showing the geology of floors and walls of structure excavations accompany this description. During the mapping of excavation, eleven fault zones were uncovered. The relationship between these faults is shown Figure 2.5.1-18 and shown in greater detail on the geology maps associated with tion 2.5.4.1.

old granite quarry is located in the Westerly Granite about 1,200 feet south-southeast of the t area. This quarry was in operation as an open pit, unsupported excavation from 1830 to

0. The rock is sound and self-supporting, and this excavation does not influence the stability he site in any way. Neither the Westerly Granite nor the Monson gneiss are ore-bearing and e are no mining activities at present and none are anticipated in the future.

h the basal and overlying ablation tills are relatively impervious. The only water flow through gneiss noted during construction was along intersecting joints that extended upward to the ace. This flow was handled quite readily by sumps located throughout the excavation.

manent sumps have been located around the structures to take care of this groundwater flow ng the operation of the plant. The site groundwater conditions are covered in detail in tion 2.4.13 and the structure dewatering system is described in Section 3.8.5.1.

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1.1-103 Sanders, J.E. 1960. Structural History of Triassic Rocks of the Connecticut Valley Belt and Its Regional Implications. N. Y. Acad. Sci., Section of Geological Sciences, p 119 132.

1.1-104 Schafer, J.P. and Hartshorne, J.H. 1965. The Quaternary of New England. In: The Quaternary of the United States. Wright, H. E., Jr. and Frey, D. C., Princeton University Press, Princeton, New Jersey, p 113-128.

1.1-105 Schnabel, R. W. 1960. Bedrock Geology of the Avon Quadrangle, Connecticut. U.S.

Geological Survey, Quadrangle Map GQ 370, Washington, D.C.

1.1-106 Sheridan, R.D. 1974. Atlantic Continental Margin of North America. In: The Geology of Continental Margins. Burk, C.A. and Drake, C. L. (ed.) Springer-Verlag, New York, p 301 407.

1.1-107 Shride, A. F. 1976. Stratigraphy and Correlation of the Newbury Volcanic Complex, Northeastern Massachusetts. In: Contributions to the Stratigraphy of New England.

Page, L. R. (ed.) Geol. Soc. America, Mem 148, p 147 178.

1.1-108 Skehan, J. W. and Abu-moustafa, A.A. 1976. Stratigraphic Analysis of Rocks Exposed in the Wachusett-Marlborough Tunnel, East-Central Massachusetts. In:

Contributions to the Stratigraphy of New England. Page, L. R. (ed.) Geol. Soc.

America, Mem 148, p 217 240.

1.1-109 Skehan, J. W. 1961. The Green Mountain Anticlinorium in the Vicinity of Wilmington and Woodford, Vermont. Vermont Development Department, Bull. No.

17.

Appalachian Geology: Northern and Maritime. John Wiley and Sons, Inc., New York, p 281 290.

1.1-111 Skehan, J.W. 1969. Tectonic Framework of Southern New England and Eastern New York in North Atlantic Geology and Continental Drift. Memoir 12, Amer.

Assn. of Petroleum Geologists, p 793 814.

1.1-112 Skehan, J.W. 1973. Subduction Zone between the Paleo-American and the Paleo-African Plates in New England. Geofisica Internacional, 13, No. 4, p 291 308.

1.1-113 Skehan, J. W. 1975. Oral Communication with L. Martin and F. Vetere, S&W.

1.1-114 Snyder, G. L. 1964. Bedrock Geology of the Willimantic Quadrangle, Connecticut.

U.S. Geological Survey, Quadrangle Map GQ 335, Washington, D.C.

1.1-115 Snyder, G. L. 1970. Bedrock Geology and Magnetic Maps of the Marlborough Quadrangle, East-Central Connecticut. U.S. Geological Survey, Quadrangle Map GQ 791, Washington, D.C.

1.1-116 Stanley, R. S. 1964. The Bedrock Geology of the Collinsville Quadrangle. State Geological and Natural History Survey, Connecticut, Quadrangle Report No. 16, Washington, D.C.

1.1-117 Stetson, H. C. 1949. The Sediments and Stratigraphy of the East Continental Margin; Georges Bank to Norfolk Canyon. Contribution No. 487 from the Woods Hole Oceanographic Institution, Woods Hole, Mass., No. 2, p 1 34.

1.1-118 Suter, R.; deLaguna, W.; and Perlmutter, N. M. 1949. Mapping of Geologic Formations and Aquifers of Long Island, New York. New York Dept. of Conservation, Water Power and Control, Connecticut, Bull. GW-18, p 212.

1.1-119 Sutter, J.F. 1971. K-Ar Relationships in Mylonite Rocks (Abs). A.G.U. Trans., V. 52,

p. 367-368.

1.1-120 Tagg, A.R. and Uchupi, E. 1967. Subsurface Morphology of Long Island Sound, Block Island Sound, Rhode Island Sound and Buzzards Bay. U.S. Geological Survey, Prof. Paper 575 C, p C92 C96.

1.1-121 Theokritoff, G. 1968 Cambrian Biogeography and Biostratigraphy in New England.

In: Studies of Appalachian Geology: Northern and Maritime. John Wiley and Sons, Inc., New York, p 9 22.

Geology: Northern and Maritime. John Wiley and Sons, Inc., New York, p 203-218.

1.1-123 Tuttle, C.R.; Allen, W.B.; and Hahn, B.W. 1961. A Seismic Record of Mesozoic Rocks on Block Island, Rhode Island. U.S. Geological Survey, Prof. Paper 424-C, p 254-330.

1.1-124 Uchupi, E. and Emery, K. O. 1967. Structural Control of Continental Margin of Atlantic Coast of Eastern United States. Amer. Assn. of Petroleum Geologists, Bull.

51, p 223 234.

1.1-125 U.S. Coast and Geodetic Survey (USCGS). 1965. Earthquake History of the United States, Part I. U.S. Dept. of Commerce, Washington, D. C.

1.1-126 U.S. Geological Survey 1972, LANDSAT Photographs E-1077-15011 and E-1096-15072, Washington, D.C.

1.1-127 Weed, E.G.A.; Minard, J.P.; Perry, W.J., Jr.; Rhodehamel, E.C.; and Robbins, E.I.

1974. Generalized Pre-Pleistocene Geologic Map of the Northern United States Atlantic Coastal Margin. U.S. Geological Survey, Quadrangle Map I 861, Washington, D.C.

1.1-128 Weston Observatory. 1976. The Pennsylvanian Coal-Bearing Strata of the Narragansett Basin. National Science Foundation, Grant No. AER76-02147.

1.1-129 Wheeler, G. 1939. Triassic Fault-Line Deflections and Associated Warping. Jour.

Geological, 47, p 337 370.

1.1-130 White, W. S. 1968. Generalized Geologic Map of the Northern Appalachian Region.

In: Studies of Appalachian Geology: Northern and Maritime. Zen (ed.) John Wiley and Sons, Inc., New York.

1.1-131 Zartman, R. E. and Marvin, R. F. 1971. Radiometric Age (Late Ordovician) of the Quincy, Cape Ann, and Peabody Granites from Eastern Massachusetts. Geological Soc. Amer., Bull. 82, p 937 958.

1.1-132 Zartman, R. E. and Naylor, R. 1972. Structural Implications of Some U Th Pb Zircon Isotopic Ages of Igneous Rocks in Eastern Massachusetts (Abs). Geological Soc. America Abs, 4, No. 7 p 5 55.

1.1-133 Zartman, R.E.; Hurley, P.M.; Krueger, H.; and Gileth, B.J. 1970. A Permian Disturbance of K Ar Radiometric Ages in New England: Its Occurrence and Cause.

Geol Soc. Amer. Bull. 81, p 3359 3374.

U.S. Geological Survey, Prof. Paper 525 D, Washington, D.C., p D1 D10.

1.1-135 Zen, E-an 1967. Time and Space Relationships of the Taconic Allochthon and Autochthon. Geological Soc. America, Spec. Paper 97, p 107.

1.1-136 Zen, E-an; White, W.S.; Hadley, J.B.; and Thompson, J.B., Jr. (ed.) 1968. In: Studies of Appalachian Geology: Northern and Maritime. John Wiley and Sons, Inc., New York.

1.1-137 Zietz, I.; Gilbert, F.; and Kirby, J.R. 1972. Aeromagnetic Map of New England. U.S.

Geol. Survey Open-File Report, 12 sheets.

ABLE 2.5.1-1 ROCK FORMATIONS OF THE COASTAL PLAIN OFF SOUTHERN NEW ENGLAND CLICK HERE TO SEE TABLE 2.5.1-1

TABLE 2.5.1-2 ROCK FORMATIONS OF WESTERN CONNECTICUT CLICK HERE TO SEE TABLE 2.5.1-2

BLE 2.5.1-3 ROCK FORMATIONS OF EASTERN CONNECTICUT AND WESTERN RHODE ISLAND CLICK HERE TO SEE TABLE 2.5.1-3

ABLE 2.5.1-4 ROCK FORMATIONS OF CENTRAL RHODE ISLAND (AND NOT INCLUDED IN PREVIOUS DESCRIPTIONS)

CLICK HERE TO SEE TABLE 2.5.1-4

TABLE 2.5.1-5 ROCK FORMATIONS IN NORTHERN AND EASTERN RHODE ISLAND AND SOUTHERN MASSACHUSETTS CLICK HERE TO SEE TABLE 2.5.1-5

TABLE 2.5.1-6 ROCK FORMATIONS OF CENTRAL MASSACHUSETTS CLICK HERE TO SEE TABLE 2.5.1-6

TABLE 2.5.1-7 EAST OF CLINTON-NEWBURY FAULT SYSTEM, EASTERN MASSACHUSETTS, AND NEW HAMPSHIRE CLICK HERE TO SEE TABLE 2.5.1-7

TABLE 2.5.1-8 DESCRIPTIONS OF LINEAMENTS FROM LANDSAT PHOTOGRAPHS (SHOWN ON FIGURE 2.5.1-10)

CLICK HERE TO SEE TABLE 2.5.1-8

FIGURE 2.5.1-1 REGIONAL PHYSIOGRAPHIC MAP Revision 3606/29/23 MPS-3 FSAR 2.5.1-45

FIGURE 2.5.1-2 REGIONAL PRE-PLEISTOCENE SEDIMENTS OF THE CONTINENTAL MARGIN Revision 3606/29/23 MPS-3 FSAR 2.5.1-46

Revision 3606/29/23 MPS-3 FSAR 2.5.1-47 FIGURE 2.5.1-3 SITE SURFICIAL GEOLOGY

Revision 3606/29/23 MPS-3 FSAR 2.5.1-48 FIGURE 2.5.1-4 REGIONAL GEOLOGIC MAP

FIGURE 2.5.1-5 REGIONAL GEOLOGIC SECTION Revision 3606/29/23 MPS-3 FSAR 2.5.1-49

Revision 3606/29/23 MPS-3 FSAR 2.5.1-50 FIGURE 2.5.1-6 REGIONAL TECTONIC MAP

FIGURE 2.5.1-7 STRATIGRAPHIC CORRELATION CHART FOR THE SITE AND SURROUNDING REGION)

Revision 3606/29/23 MPS-3 FSAR 2.5.1-51

FIGURE 2.5.1-8 REGIONAL STRATIGRAPHIC CORRELATION CHART (SHEET 1)

Revision 3606/29/23 MPS-3 FSAR 2.5.1-52

FIGURE 2.5.1-8 REGIONAL STRATIGRAPHIC CORRELATION CHART (SHEET 2)

Revision 3606/29/23 MPS-3 FSAR 2.5.1-53

FIGURE 2.5.1-8 REGIONAL STRATIGRAPHIC CORRELATION CHART (SHEET 3)

Revision 3606/29/23 MPS-3 FSAR 2.5.1-54

FIGURE 2.5.1-9 LANDSAT PHOTOGRAPHS OF CONNECTICUT, RHODE ISLAND, SOUTHERN MASSACHUSETTS, AND EASTERN NEW YORK Revision 3606/29/23 MPS-3 FSAR 2.5.1-55

FIGURE 2.5.1-10 LINEAMENT MAP FROM LANDSAT PHOTOGRAPHS Revision 3606/29/23 MPS-3 FSAR 2.5.1-56

Revision 3606/29/23 MPS-3 FSAR 2.5.1-57 FIGURE 2.5.1-11 REGIONAL AEROMAGNETIC MAP

FIGURE 2.5.1-12 REGIONAL BOUGUER GRAVITY MAP Revision 3606/29/23 MPS-3 FSAR 2.5.1-58

Revision 3606/29/23 MPS-3 FSAR 2.5.1-59 FIGURE 2.5.1-13 SITE BEDROCK GEOLOGY

FIGURE 2.5.1-14 TECTONIC MAP OF EASTERN CONNECTICUT Revision 3606/29/23 MPS-3 FSAR 2.5.1-60

Revision 3606/29/23 MPS-3 FSAR 2.5.1-61 FIGURE 2.5.1-15 CONTOUR DIAGRAM OF POLES TO FOLIATION PLANES - FINAL GRADE

Revision 3606/29/23 MPS-3 FSAR 2.5.1-62 FIGURE 2.5.1-16 CONTOUR DIAGRAM OF POLES TO JOINT PLANES - FINAL GRADE

Revision 3606/29/23 MPS-3 FSAR 2.5.1-63 FIGURE 2.5.1-17 CONTOUR PLOT OF BEARING AND PLUNGE OF SLICKENSIDES - FINAL GRADE

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.1-18 GENERALIZED LOCATION OF FAULTS Revision 3606/29/23 MPS-3 FSAR 2.5.1-64

site region is characterized by earthquakes of low to moderate intensity. During the past 300 rs, only 13 earthquakes greater than or equal to Intensity V Modified Mercalli (MM) have n reported within 50 miles of the site. The site lies in the Southeastern New England-Maritime tonic Province. The largest earthquake in this province was an Intensity VI (MM) event which urred in 1904 east of Eastport, Maine. Two moderate size earthquakes have occurred in the odus, Connecticut area, located in the adjacent New England Province, in 1568 (Intensity VII M)) and 1791 (Intensity VI-VII (MM)). The maximum earthquake potential at the site is med to be due to an earthquake of Intensity VII (MM) occurring close to the site. This esponds to a peak ground acceleration of 0.10 g. The safe shutdown earthquake (SSE) has servatively been specified as 0.17 g. The operating basis earthquake (OBE) has been specified

.09 g, which corresponds to approximately half the SSE.

2.1 SEISMICITY st of the information on earthquake activity in the northeastern United States is based on orical reports, old diaries, and newspaper accounts. These earthquakes are classified on the s of intensity corresponding to the Modified Mercalli scale. This scale, developed in 1931 and cribed in Table 2.5.2-1, is based on observations of the effects of earthquakes and damage to ctures. The instrumental monitoring of earthquakes began in the mid 1920s in the northeastern ted States. Magnitude, a measure of earthquake energy, is determined from instrumental data.

number of seismographic stations has greatly increased in recent times. At present, Weston ervatory of Boston College, Lamont-Doherty Geological Observatory of Columbia versity, Massachusetts Institute of Technology, University of Connecticut, Pennsylvania State versity, and Delaware Geological Survey operate seismographic stations in the northeast and rdinate the publication of the Northeastern United States Seismic Network (NEUSSN) etin. Figure 2.5.2-1 shows the location of stations in this network and Table 2.5.2-2 lists the tions and other pertinent data for these stations. Historical reports of earthquakes and rmation obtained from instrumental coverage in recent years form the basis of this mination of the seismicity of the site region.

2.1.1 Completeness and Reliability of Earthquake Cataloging n though major historical catalogs carry entries dating back almost three centuries, the erage of this period is not continuous. The completeness and reliability of the data are related population distribution and, recently, to the seismograph network coverage. Therefore, uracy of epicentral coordinates and the assigned maximum intensities must be evaluated fully.

the earlier historical events, epicenters were located closer to population centers due to the ence of reports from the true epicentral area. The intensity of an earthquake at a given location ends not only on accurate and complete human observations, but also on foundation ditions, design, type, and quality of building construction. Construction practices, particularly himneys in the earlier centuries, were certainly not those envisioned in the Modified Mercalli

mological information for the instrumental period (since 1900) must also be evaluated fully. Seismic instrumentation began in the early 1900s in the United States and Canada with gressively improved quality of earthquake data. Epicentral locations based on felt reports were plemented and somewhat controlled by instrumental data. From the 1900s until the 1960s, y a few seismographs operated in the eastern United States. Most of these stations were part of regional network operated by the Jesuit Seismological Association. In the early decades, erous factors, such as the type of instrumental response, lack of accurate time control, ward configuration, use of graphical methods, and limited knowledge of crustal velocities e potential sources of errors. These produced large uncertainties in the epicentral coordinates ch, in many cases, amounted to tens of kilometers.

ce the 1960s, increased interest in understanding local seismicity has resulted in the lementation of dense seismographic networks. Seismic data in the northeastern United States now gathered by NEUSSN and reported in its bulletin. NEUSSN reports earthquake ocentral locations and magnitudes determined through the cooperation of several institutions.

hough the coverage of this network is uneven, it is now capable of detecting and locating all hquakes in New England of magnitude greater than or equal to 2.0 (Chiburis 1979; Sbar and es 1977). Chiburis (1979) has recently examined the seismicity of New England based on nt earthquakes and has reevaluated the location and intensity of several earlier events.

2.1.2 Earthquake History dies of the earthquake history of the site region are based on the Chiburis (1979) catalog.

le 2.5.2-3 lists all earthquakes with intensity greater than or equal to IV (MM) within 200 es of the site and all instrumentally located earthquakes regardless of magnitude. The table lists the date, origin time, epicentral coordinates, epicentral intensity, magnitude, seismic ment, and a description of location. Except for the seismic moments, which were determined Street and Turcotte (1977), all other information is from Chiburis (1979). The earthquakes d in Table 2.5.2-3 and plotted on Figure 2.5.2-2 show that the site is located in an area of low oderate seismicity.

cumulative historical seismicity data (Figure 2.5.2-2) reveal the presence of several distinct s of concentrated seismic activity. They are: Moodus, Connecticut; Narragansett Bay, Rhode nd; Cape Ann, Massachusetts; the area around Ossipee, New Hampshire; northern New York; theastern New York; northeastern New Jersey; and the Hudson River Valley. These are ussed in terms of their location, areal extent, level of historical seismicity, and their tectonic ework as inferred from current research.

Activity in Southern New England as of central Connecticut, near East Haddam and Moodus, and the region near Narragansett in Rhode Island and southeastern Massachusetts have experienced a low level of activity.

nts ranging in magnitude to approximately 3.5.

Activity in Southeastern New York and Northeastern New Jersey seismic activity in southeastern New York, eastern Pennsylvania, and New Jersey is racterized by several repeated occurrences of Intensity VII (MM) earthquakes. Three of these nts occurred near New York City in 1737, 1884, and 1927. Two others occurred in thwestern New Jersey in 1840 and 1871. Several Intensity VI events are also distributed ughout this area of low level activity.

ent investigations by Page et al. (1968), Aggarwal and Sykes(1978), and Sbar and Sykes

77) propose a spatial correlation of instrumentally recorded, small earthquakes with the mapo fault system, which extends in a northeasterly direction parallel to the Appalachian trend his region. Available focal mechanism solutions for this area, by Aggarwal and Sykes (1978),

gest high angle reverse faulting along planes that parallel mapped or inferred segments of the heast-trending Ramapo system.

White Mountains Plutons area of central New Hampshire and northeastern Massachusetts, including the Cape Ann

, once considered to be a segment of a continuous Boston-Ottawa seismic trend by Sbar and es (1973), is presently interpreted as a separate seismic region. Recently, Sbar and Sykes

77) have recognized the presence of a seismicity gap in Vermont and western New Hampshire.

ensive regional investigations, geological and geophysical, conducted for the Preliminary ety Analysis Report (PSAR) of Pilgrim Unit 2 (BECo 1976a), have stressed the individual ty of this seismic zone. The largest events to affect this region are the Intensity VIII (MM) e Ann earthquake of 1755 and three Intensity VII (MM) events, one near Cape Ann in 1727, two near Ossipee, New Hampshire on December 20 and 24, 1940. Street and Turcotte (1977) gest a magnitude of 5.4 for the Ossipee events, based on reanalysis of several seismograms.

larger earthquakes in the Ossipee and Cape Ann areas have been individually correlated to ain plutons of the White Mountains series in combination with anomalous country rock ting in the Pilgrim Unit 2 PSAR (BECo 1976a), whereas the Nuclear Regulatory Commission associated these earthquakes with a larger zone of weakness, and the United States Geological vey, following Hadley and Devine (1974), has correlated the earthquakes with northeast-ding faults.

ent activity in this region, including central New Hampshire and the Cape Ann area, appears e low. Two events ranging in magnitude to just over 3.0 have been reported in the last decade.

seismicity of Maine, characterized by a maximum Intensity VI (MM), is spatially distributed he central and west-central regions, the New Brunswick border area, and the Quebec border on near northern New Hampshire.

o Intensity VI (MM) earthquakes, one located in the ocean off Portland in 1957 and the other r the Maine-Quebec border in 1973, are both assigned magnitudes of 4.8. For the 1973 event, miller (1975) determined an oblique strike-slip focal mechanism with nodal planes oriented 4E and N37W.

Hudson River Valley earthquake epicenters have been located in the Hudson River Valley. The largest of these hquakes was Intensity VII (MM) near Lake George, New York, on April 20, 1931.

hough a number of large earthquakes (Intensity IX-XI (MM)) have occurred in the St.

rence River Valley, these earthquakes fall outside the 200-mile radius and, therefore, are ussed in Section 2.5.2.4 with relation to maximum earthquake potential at the site.

cumulative historical seismicity data, carefully interpreted, can yield valuable information on spatial and temporal distribution of larger and more significant earthquake events and the tion of zones of concentrated activity. Four years of operation of the NEUSSN have produced mplete record of accurately located events of magnitude 1.8 to 2.0 and larger in the region.

r and Sykes (1977) and Chiburis (1979) have noted that the spatial distribution of this rumental seismicity closely tracks the distribution of less accurately located historical events, reinforcing confidence that older events are fairly well located and that areas of seismic vity are relatively stationary.

2.1.3 Seismicity within 50 Miles of the Site thquake activity within 50 miles of the site is listed in Table 2.5.2-4 and shown on ure 2.5.2-3. There have been 50 earthquakes of intensity greater than or equal to Intensity IV M). Almost half of this earthquake activity has occurred in the Moodus-East Haddam area, ut 25 miles northwest of the site. A temporary microearthquake network (five stations) has n installed in this area by Professor E. Chiburis of Weston Observatory to examine the nature significance of this activity.

ge earthquakes have occurred in the Moodus area in 1568, with epicentral Intensity VII (MM),

on May 16, 1791, with Intensity VI-VII (MM) (Chiburis 1979). The earthquake of May 16, 1, was felt over an area of 35,000 square miles extending from Boston to New York. Several rshocks were reported for the next few days.

ce 1791, at least 40 earthquakes have been lightly felt in the East Haddam-Moodus area. A derate earthquake took place in the same epicentral area on November 14, 1925 and, although portedly did some minor damage at Hartford and Windham, it was not strong enough to be

rmined epicenter about 19 miles northwest of the site. The earthquake had a maximum nsity of IV (MM) and was generally felt from Old Lyme, Connecticut, on the south to East tford on the north. The most recent earthquake in the Moodus area was of magnitude 2.2 in 6.

thquake activity within 10 miles of the site has been limited to four very slight earthquakes h maximum intensities of Intensity III (MM). Two of these earthquakes occurred in New don on November 23, 1894 and August 9, 1935; one occurred in Groton on August 1, 1852; the fourth was felt in Mystic, Moodus, and Norwich on September 20, 1938.

2.1.4 Earthquakes Felt at the Site determine the earthquake hazard at the site, it is necessary to examine how severely the site has n affected by large earthquakes in the past. This examination for Millstone 3 is based on ilable historical records. A discussion of these earthquakes follow.

June 11, 1638 (46.5N, 72.5W, Intensity IX (MM))

s earthquake, centered in the St. Lawrence River Valley, probably near Three Rivers, Quebec, felt throughout New England with no damage reported except to chimneys at Plymouth and m, Massachusetts. Perley (1891) described the chimneys at Plymouth as follows: The mneys of the first houses here were built on the outside at the ends of the houses, with the tops ng just above the roof. They were massive piles of rough and uneven stones, generally some feet square, besides being nearly perpendicular. Imperfectly built, without mortar except for ng, they readily yielded to the terrible shaking they received, and the tops of many of them fell striking on the house or on the ground. Felt (1899) reported that the shock was felt in necticut, Narragansett, Pascataquack, and surrounding areas. Based on available reports and intensity attenuation characteristics of other earthquakes occurring in the vicinity of the St.

rence River Valley, the estimated maximum intensity of the earthquake at the site was IV-V M).

February 5, 1663 (47.6N, 70.1W, Intensity X (MM))

s earthquake was centered in the St. Lawrence River northeast of Quebec City and was felt r a 750,000-square-mile area of eastern North America, accompanied by landslides along the Maurice, Batiscan, and St. Lawrence Rivers. Other damage was confined to cracked chimneys the like. Effects in New England were similar to those of the 1638 earthquake. Brigham

71) reported that on the shore of Massachusetts Bay, houses were shaken so that pewter fell m the shelves and the tops of several chimneys were broken. Based on available reports and nsity attenuation characteristics of other earthquakes occurring in the vicinity of the St.

rence River Valley, the estimated maximum intensity of this earthquake at the site was IV-V M).

epicenter of this earthquake was located off the coast of northeastern Massachusetts.

ximum damage in the intensity range of VI to VII (MM) occurred near the mouth of the rimack River where no buildings were thrown down but parts of walls of several cellars fell nd the tops of many chimneys were shaken off (Crowell, 1868). Slight damage equivalent to nsity V (MM) consisting of cracked chimneys was noted as far north as Portsmouth, New mpshire; as far west as Lowell, Massachusetts; and as far south as Boston, Massachusetts. The hquake was felt over an estimated area of 75,000 square miles from the Kennebunk River in ne to the Delaware River south of Philadelphia. The intensity distribution of this earthquake is wn on Figure 2.5.2-4. Based on available reports, the estimated maximum intensity of this hquake at the site was IV (MM).

September 16, 1732 (45.5N, 73.6W, Intensity VIII (MM))

s earthquake was centered near Montreal where 300 homes were damaged and 7 people were ed. It was felt in Boston and throughout New England and possibly as far south as Maryland.

ed on available reports and the intensity attenuation characteristics of other earthquakes urring in the vicinity of the St. Lawrence River Valley, the estimated maximum intensity of earthquake at the site was IV (MM).

December 18, 1737 (40.8N, 74.1W, Intensity VII (MM))

s earthquake appears quite similar to the earthquake of August 10, 1884, in that it was felt m Boston, Massachusetts, to New Castle, Delaware and the epicenter was located in the New k City area where some chimneys were thrown down and bells rang. Although the damage in epicentral area appears similar, it is possible that the epicentral intensity of the 1737 hquake may have been one intensity less (or Intensity VI (MM)) due to the difference in the struction quality over the 147-year interval between earthquakes. Based on available reports a comparison of this earthquake with the 1884 earthquake, the probable intensity in the nity of the site was IV (MM) with an estimated maximum intensity of V (MM).

November 18, 1755 (42.7 0.1N, 70.3 0.1W, Intensity VIII (MM))

s earthquake had its epicenter off the Massachusetts coast, east of Cape Ann. It was felt over stimated area of 300,000 square miles from the Chesapeake Bay in Maryland on the south to Annapolis River in Nova Scotia on the north and from Lake George in New York on the west pproximately 200 miles east of Cape Ann (ship thought to have run aground). Most of the age (Intensity VI (MM) or greater) from this earthquake occurred along the coast from the w Hampshire-Massachusetts line south to the Boston area. Some slight damage to chimneys ensity V (MM)) occurred as far north as Portland and Brunswick, Maine; as far south as uate, Massachusetts; and as far west as the Lowell, Massachusetts and Nashua, New mpshire area. The intensity distribution for this earthquake is shown on Figure 2.5.2-5.

orts, the estimated maximum intensity of this earthquake at the site was V-VI (MM).

May 16, 1791 (41.5N, 72.5W, Intensity VI-VII (MM))

epicenter of this earthquake was located in the vicinity of East Haddam, Connecticut. This hquake was felt over an area of 35,000 square miles extending from Boston to New York.

mination of the dates and times mentioned in the technical references suggests that a number arthquakes occurred; the first and largest on May 16, 1791, at 8:00 pm, with a number of rshocks during the next few days.

only reports of damage were from the East Haddam area where stone walls and the tops of mneys were thrown down and latched doors were thrown open. Linehan (1964) reports that a up of professors from Wesleyan University visited the East Haddam area in 1841 and was able onfirm these reports. However, contrary to the original reports, the professors found that only large stone had been displaced (it was in a tenuous position to begin with) and that no fissures opened in the earth.

ty houses of pre-1791 construction were still occupied in the East Haddam-Middletown area ate as 1938. A study of the houses in the East Haddam area shows that they were not of sturdy struction nor had deep foundations, yet none were structurally damaged in the 1791 hquake. The fact that some stone walls or chimneys might have been damaged could be buted to an earthquake of intensity not more than V (MM), as there was little brick used and stones were glacial cobbles. Clay and fibers made up the morta (Linehan 1964).

vious reports of this earthquake placed the intensity at VIII (MM). However, Linehan (1964) cludes that the intensity of the seismic event which was felt in East Haddam on May 16, 1791 no greater than V-VI (MM). If the disturbance was of Intensity VIII (MM), the damage ld have been considerable in ordinary substantial buildings, with partial collapse, as defined he MM scale. There is no record of any damage to buildings, even though most of these were rly constructed. Therefore, the intensity of these earthquakes could have been no higher than VII (MM).

wspaper accounts indicate that the earthquake was strongly felt without any reported damage artford or New Haven, Connecticut. The intensity distribution for this earthquake is shown on ure 2.5.2-6. Based on Linehan's analysis of the earthquake's effects in the East Haddam-odus area and other available accounts, the estimated maximum intensity of the earthquake in vicinity of the site was V (MM).

October 17, 1860 (47.5N, 70.1W, Intensity VII to IX (MM))

s earthquake had its epicenter in the St. Lawrence River Valley, northeast of Quebec City, and felt over an area of 700,000 square miles extending as far south as Newark, New Jersey, and ar west as Auburn, New York and included most of New England. The earthquake was ngly felt in Maine, but no damage was reported there or elsewhere in New England. Based on

site was IV (MM).

October 20, 1870 (47.4N, 70.5W, Intensity IX (MM))

s earthquake was centered near Baie-St. Paul, Quebec, and was felt over a 1,000,000 square-e area of eastern Canada and the northeastern United States. The damage reported in the ted States included some bricks thrown from chimneys in Lewiston, Maine and some window s broken in Portland, Maine. In Springfield, three distinct periods of vibration were noticed h the longest estimated at 7 to 8 seconds; while at Hartford, a single shock lasting a minimum 0 seconds was felt.

ed on available reports, the estimated maximum intensity of this earthquake at the site was IV M).

August 10, 1884 (40.6N, 70.4W, Intensity VII (MM))

s earthquake was felt over an estimated 70,000 square-mile area of the northeastern United es and had its epicentral location in the New York City area. The greatest damage occurred in aica and Amityville on western Long Island, New York, where some walls were cracked, ounting for the epicentral intensity of VII (MM). The epicentral location is further evidenced moderate aftershock which took place on August 11, 1884, and was felt in a number of towns western Long Island.

analysis of this earthquake by Rockwood (1885) resulted in the isoseismal map shown on ure 2.5.2-7. Rockwood's map was based on more than 215 observations, of which 30, all hin Rockwood's Isoseismal IV, reported some damage such as fallen bricks and cracked ter. As shown on the figure, the site is located within Rockwood's Isoseismal III.

he southern Connecticut area, damage included some bricks shaken from chimneys and a few ked walls at New Haven, and dishes thrown from shelves and broken at Bridgeport. The ck was strongly felt at Hartford, but no damage was reported.

ew London, the earthquake was felt by everyone and the water in the harbor was reportedly ated. Reports also indicate a few instances of cracked and fallen plaster but no damage to mneys (The Day 1884).

ed on Rockwood's data and other available reports, the estimated maximum intensity in the area was V (MM).

February 10, 1914 (45N, 76.9W, Intensity VII (MM), Magnitude 5.5) s earthquake had its epicenter about 25 miles west of Lanark, Ontario, and was felt over a

,000 square-mile area including New England, New York State, and Pennsylvania. Some age was reported in New York State with minor damage noted as far east as Albany. The

vailable reports of this earthquake, the estimated maximum intensity at the site was IV (MM).

March 1, 1925 (47.6N, 70.1W, Intensity IX (MM), Magnitude 7.0) s earthquake, which had its epicenter in the St. Lawrence River Valley northeast of Quebec

, was felt over approximately 2,000,000 square miles of North America, extending as far th as Virginia and west to the Mississippi River. Important damage was confined to a narrow along the St. Lawrence River Valley. Isoseismals prepared by the Dominion Observatory of ada and shown on Figure 2.5.2-8 indicate that most of New England experienced intensities II and IV (MM), the exception being extreme northern Maine, which probably experienced an nsity of V to VI (MM). The shock was generally felt throughout Connecticut with a maximum nsity of IV (MM) in the site area.

November 14, 1925 (41.5N, 72.5W, Intensity V to VI (MM))

s earthquake was felt over an 850 square-mile area of central Connecticut. Minor damage was orted at Hartford where some plaster fell and at Windham where dishes fell from shelves.

wspaper reports indicated that the earthquake was strongly felt from the Haddam-Middletown to Hartford.

ng the southern Connecticut coast, the earthquake was generally felt but no damage reported.

ilable reports indicate intensities of III to IV (MM) in the site area.

December 20, and 24, 1940 (43.8N, 71.3W, Intensity VII (MM), Magnitude 5.8) epicenters of these earthquakes were located near Lake Ossipee, New Hampshire. Damage of nsity VII (MM) occurred at Tamsworth and Wonalancet, New Hampshire, while damage of nsity VI (MM) was noted in a dozen localities in central New Hampshire and western Maine.

shocks were felt over a 150,000 square-mile area of the United States including all of New land, New York, and New Jersey. The earthquakes were noticeably felt in the vicinity of the but no damage was reported.

isoseismal map prepared by the Northeast Seismological Association, Figure 2.5.2-9, cates that the intensity of these earthquakes in the vicinity of the site was IV (MM).

2.2 GEOLOGIC STRUCTURES AND TECTONIC ACTIVITY site region encompasses a large segment of the northern Appalachian region. This region has ergone at least four orogenies, Mesozoic rifting and igneous activity, epeirogenic uplift, and iation. The tectonics and geologic history are discussed in Section 2.5.1. Figure 2.5.2-2 ws the regional geologic structure and the locations of epicenters within the 200 mile radius of site.

White Mountains Plutonic Province -- comprise most of the area. The remaining provinces the Coastal Plain, the Blue Ridge and Piedmont, the Northern Valley and Ridge, the alachian Plateau, the Central Stable Region, the Grenville, and the Monteregian Plutonic vince. The provinces are delineated on the basis of the following criteria:

1. Style and degree of deformation

2. The age of orogenic, igneous, or tectonic activity

3. The age of the basement rocks se provinces are shown on Figure 2.5.2-10.

Southeastern New England-Maritime Province site is located in the southwestern edge of the Southeastern New England-Maritime Province.

western boundary follows the Honey Hill Lake Char-fault system northward into ssachusetts. The rock fabric and structural trends are different than those of the New England vince to the west. The province is characterized by Late Precambrian basement rock overlain mildly metamorphosed rocks of Carboniferous age. Unlike the remainder of New England, the cts of the Alleghenian orogeny are apparent within the province.

Southeastern New England area is considered by Skehan (1973) to be a piece of the Paleo-ican continental plate with the Clinton-Newbury fault zone being the collision boundary.

gers(1970) considers the rocks east of the Clinton-Newbury fault to be similar to those of the lon Peninsula of Newfoundland. The reopening of the Atlantic Ocean, which began in the sozoic, isolated the pieces of the African continent. Gravity and magnetic data also indicate the province boundary represents a juncture between two discrete crustal blocks in near tatic equilibrium.

erse faulting is prominent in the intensely faulted zone between the Clinton-Newbury and e Char faults and the Boston Border fault, although transcurrent or strike-slip components exist. Northeastward along the Norumbega fault, the movement has been right lateral and exceed several hundred kilometers. Skehan (1973) considers the area to be an ancient duction zone, although all the elements have not been demonstrated. Certainly, large scale erthrusting has played a major role in the development of the province.

New England Province west of the Southeastern New England-Maritime Province lies the New England Province, nding southward to 4030'N latitude. The New England Province is structurally similar to the dmont. The region has been strongly affected by the Taconic and Acadian Orogenies, whereas Blue Ridge and Piedmont Province and the Valley and Ridge Province to the south were cted by the Alleghenian orogeny. Grenville-age basement is exposed in the cores of the

cambrian basement disappears beneath the high grade metamorphic rocks of the Merrimack clinorium to the east. The structural fabric of the province suggests a Paleozoic compressive ss directed from the east or southeast. The presence of the New Hampshire Plutonic series laced during the Acadian Orogeny aids in distinguishing the New England Province from the theastern New England-Maritime Province.

White Mountains Plutonic Province emplacement of magmas of the White Mountains Plutonic-Volcanic Series began in the sozoic and overprinted the Paleozoic effects. The series was intruded along a north-northwest d extending offshore of Cape Ann, Massachusetts, into northern New Hampshire, Vermont, southern Quebec, crossing the older structural grain of the Appalachians. Radiometric dating shown that the igneous activity began in and continued sporadically throughout the Mesozoic (BECo 1976a). All the plutons are related in age, shape, magnetic signature, gross eralogy, and mode of intrusion. The zone has been spatially correlated with a region of mic activity in New Hampshire and Massachusetts.

s zone is defined to include all mapped occurrences of White Mountains Plutonic-Volcanic es rocks and is extended offshore to include a group of magnetic anomalies similar to the hore structures. It extends northwestward to include Mt. Ascutney in Vermont and northward ncompass Mt. Megantic in southern Quebec. Southeastward, it includes the Agamenticus plex and Cape Nedick pluton.

Monteregian Plutonic Province s province, which represents an overprinting similar to the White Mountains intrusives, is posed mainly of alkaline, basic, and ultrabasic intrusives of Cretaceous age. They intrude y Paleozoic folded metasedimentary and undeformed sedimentary rocks of the New England vince. The trend of the plutonic belt cuts across the Paleozoic structural grain. The Cretaceous

, duration and mode of emplacement, size of plutons, extreme alkalic nature, contact tionships, and evidence of explosive activity distinguish the Monteregian plutons from the ite Mountain Series. The zone is defined to include all known occurrences of Monteregian rocks including several subsurface magnetic anomalies. It extends to the Oka Complex on northwest and surrounds Mt. Shefford and Mt. Brome on the northeast. The zone includes the tingsville stock near Rutland, Vermont, and all known alkalic dike occurrences in the mplain Valley. It has also been the site of a moderate amount of seismic activity and includes September 16, 1732, Intensity VIII (MM) event near Montreal.

Coastal Plain Province Atlantic Coast section of this province lies seaward of the Piedmont, New England, and theastern New England-Maritime Provinces. It is characterized by gently seaward-dipping, onsolidated Jurassic, Cretaceous, and Tertiary sediments overlying Precambrian or Early

tonically, the province is characterized as a zone of subsidence, occurring mainly since the ssic and persisting through most of the Tertiary. Several arches and embayments exist in the ement rocks and serve to subdivide the Coastal Plain into distinct sedimentary basins, some of ch contain between 10 and 12 km (32,800 and 39,400 ft) of sediments of Jurassic age and nger. Most of the deposits were placed in relatively shallow water indicating a progressive nwarping of the edge of the continent toward the oceanic floor.

Grenville Province Grenville Province borders the New England Province on the northwest and forms a belt 250 es wide from Lake Huron to the Atlantic in Labrador. The rocks of the province are divided ost evenly between medium grade marbles, quartzites and gneisses, and higher grade gneisses plutonic rocks of a slightly older series. An appendage of the Grenville Province occurs in w York State as the Adirondack uplift. Distinctive anorthosite bodies of the Adirondacks are uded in the Grenville Province because they were deformed during the Grenville orogeny ween 1.1 and 1.3 billion years ago. The Grenville Province appears to be an orogenic belt built inst the stabilized older part of the shield and is more nearly comparable to the orogenic belts he Paleozoic.

er Paleozoic platform rocks do exist in the Ottawa-Bonnecherre graben west of Logan's Line thin veneer on Grenville basement rocks. They represent a portion of the Central Stable ion which has been isolated by the uplift of the intervening Adirondacks. Their tectonic ility is related to the general stability of the underlying Grenville and, therefore, for simplicity, are included in the Grenville Province.

Piedmont-Blue Ridge Province Piedmont-Blue Ridge Province is characterized by metamorphosed Precambrian and Early ozoic eugeosynclinal rocks which were deformed during the Taconic and Alleghenian genies and may have been recrystallized during the Acadian orogeny. It includes the Blue ge anticlinorium, a relatively narrow belt of folded and faulted upper Precambrian crystalline sts and gneisses which were thrust westward several kilometers over the rocks of the valley ridge. Terrains of intrusive igneous rocks are notable in the Piedmont of Virginia and North olina. Long, narrow, graben structures filled with continental deposits of late Triassic age are erimposed intermittently on the crystallines from Pennsylvania to South Carolina. The effects each orogeny had on the rocks in the Piedmont are not yet fully understood due to the lack of rop, lack of fossils, and the strong recrystallization.

southern and eastern boundaries of the Piedmont are drawn at the present westward limit of taceous Coastal Plain deposits. Piedmont geology certainly continues beneath the Coastal n for some distance but the line where Coastal Plain mobility becomes the dominant force is ently not well established. The northern boundary of the Piedmont with the New England vince is hidden beneath the Triassic Newark Basin.

Appalachian Plateau Province borders the Central Stable Region on the east and on the south ts limit in New York. Geologically, the province is a broad, gentle, elongated basin whose ngest rocks are of probable Early Permian age. The basin forms the western part of the former alachian geosyncline with sediments thickening generally southeastward from the Cincinnati-dlay arch. Grenville basement dips beneath the province in the same direction. The basement dient steepens through central Ohio demarking the westernmost edge of Appalachian Plateau vince (USNRC 1977). Deformation of the province had its greatest development during the t-Early Permian Allegheny orogeny and resulted in gentle folding and uplift of the mentary pile with perhaps some decollement movements along weak units within the section.

d epeirogenic movements have been the only tectonic events to affect the province since Late ozoic time.

Valley and Ridge Province Valley and Ridge Province lies east of the Appalachian Plateau except at the north end where New England Province intervenes. The Valley and Ridge Province contains the major portions he sediments which were deposited in the Appalachian geosyncline, of which it comprises the theastern part. The province is characterized by unmetamorphosed Paleozoic sediments that e tightly folded and faulted during the Allegheny orogeny, about 250 million years ago.

nse pressure exerted from the southeast folded the sediments into large synclines and clines, some strongly overturned to the northwest. Thrust faults were commonly developed, icularly south of Central Virginia. The Valley and Ridge Province has been divided into hern and southern sections based on the difference in structural styles. The northern section is inated by folding, whereas the southern section is characterized by thrust faulting. In ition, the southern section has historically experienced a higher level of seismic activity while northern section is nearly aseismic (USNRC 1977, USNRC 1978). The boundary between the provinces is somewhat indistinct but is believed to occur between Roanoke and the James er in Central Virginia, roughly along latitude 37-45' north. A striking change in the trend of ey and Ridge structures also occurs at this line; the folds to the north trend about N25 E, reas the faults to the south trend N70E. The nature of the structural discontinuity is not wn but may be related to basement transcurrent faulting (Cardwell, et al., 1968).

Central Stable Region Central Stable Region is the westernmost tectonic province of concern to the analysis tained herein. The province is bounded on the east by the Appalachian Plateau Province and north and northeast by the Grenville Province and the New England Province. The Coastal n bounds the province on the south. The Central Stable Region extends westward to the east k of the Rocky Mountains and includes a wide variety of morphology and structure. The vince is made up of a foundation of Precambrian crystalline rock with a veneer of sedimentary er which varies widely in thickness. It represents the craton or central stable area of the North erican crustal plate. Deformation since the Precambrian has been restricted to the elopment of several broad basins, arches, domes, and similar features. Several of the basins

nwarps followed by long periods of erosion. The eastern boundary of the province represents western limit of effects from the Allegheny orogeny. The boundary follows the steepening of basement contours as the gradient increases to form the Appalachian Basin.

2.3 CORRELATION OF EARTHQUAKE ACTIVITY WITH GEOLOGIC STRUCTURES OR TECTONIC PROVINCES relationship between earthquake locations and geologic structures is important in assessing hquake hazard for a particular site. The absence of major spatial displacements through orical times that might be associated with tectonic activity in eastern United States makes the ciation of larger historical earthquakes with specific structures difficult. Only during the past to 15 years have seismologists been able to determine earthquake locations with sufficient ision to relate them to geologic structures.

2.3.1 Correlation with Geologic Structures White Mountain Plutons majority of the significant seismic activity in New England has been associated with the ite Mountains Plutonic Province. The strong concentration of events in southern New mpshire and northeastern Massachusetts has been spatially associated with plutons of the ite Mountains (Figure 2.5.2-2). A detailed investigation of the White Mountains Plutons has cated that the Ossipee, New Hampshire, earthquakes and the Cape Ann earthquake are ciated with the plutons (BECo 1976a). The largest activity was located off Cape Ann in 1755.

as assigned Intensity VIII (MM). Also, there have been a number of Intensity VII (MM) nts, two in Ossipee, New Hampshire in December 1940, and another located off Cape Ann in 7.

Ramapo Fault Ramapo fault system, which bounds the Triassic-Jurassic Newark graben on its northwest in northeastern New Jersey and southeastern New York, has been known for about 100 years has been commonly presumed to be an inactive fault. Aggarwal and Sykes (1978) have erved a spatial correlation of some epicenters in southeastern New York with surface traces of ts in the area. A large majority of events lie on or very close (0.5 to 1.2 miles) to the faults.

thermore, an examination of focal mechanism solutions shows that for each of the solutions, of the nodal planes trends north to northeast, which is also the predominant trend of the faults his area. The spatial correlation of one nodal plane with the trend of the mapped faults suggests earthquakes in this area occur along pre-existing faults.

sidering both geology and seismicity, the Ramapo fault is not considered capable in ordance with the criteria for capable faults in 10 CFR 100, Appendix A. This was established he Atomic Safety and Licensing Board (USNRC 1977) in 1977, after extensive hearings on issue.

most earthquake activity in the site region cannot be correlated with geologic structures, it is med (in accordance with 10 CFR 100, Appendix A) that these earthquakes are associated h the tectonic provinces (Figure 2.5.2-10) in which they occur. A discussion of earthquake vity in various tectonic provinces follows.

ch of the seismicity of the Grenville Province is associated with the LaMalbaie seismic zone the Monteregian Plutonic Zone, considered to be separate source areas and described below.

remaining activity is confined to a broad belt of epicenters extending from the Adirondack ft northwestward into southwestern Quebec and eastern Ontario to the vicinity of Kirkland

e. The largest historical events in this province were the 1944 Cornwall-Massena event of nsity VIII (MM) and the 1935 Timiskaming, Quebec earthquake of magnitude 6.2 which had picentral intensity of VII (MM).

Monteregian Plutonic Province overprints the older structural features of the Grenville and w England Provinces. Its seismicity includes the easternmost part of the prominent belt of enters which trends northwestward across the Grenville Province. The largest historical hquake within the Monteregian Plutonic Province occurred at Montreal in 1732. Earlier logs have listed this event as Intensity IX (MM); however, recent evaluations of original ounts (Chiburis 1979; NYSE&G 1978) conclude that the epicentral intensity did not exceed I (MM).

LaMalbaie Seismic Zone lies outside the 200-mile radius on the boundary between the nville Province and the New England Province. It occurs as a distinct concentration of enters extending northeast from Quebec City. The LaMalbaie Zone is the most important mic source in the northeast in terms of energy released. Historically, numerous large hquakes have occurred in this zone with intensities ranging from VII to X (MM). A junction of the Charlevoix meteoritic impact structure with the tectonic boundary between the nville Province and the Appalachian structures of the New England Province has been cribed by Leblanc and Buchbinder (1977) as a likely structural basis for the concentration of in release in this zone.

major seismicity of the New England Province is related to the White Mountains Plutonic vince described above. The remainder of the province is characterized by a band of activity ch trends along the coast from northern New Jersey to eastern Connecticut. This area has erienced earthquakes up to Intensity VII (MM). These have occurred in 1737 and 1884 at New k City and 1791 at Haddam, Connecticut. Another diffuse pattern of epicenters of maximum nsity VI (MM) occurs in coastal and central Maine. Minor microearthquake activity is also orted to originate along the Ramapo fault in New Jersey and New York (Aggarwal and Sykes 8).

thquakes in 1568 and 1791 near East Haddam, Connecticut, are also part of the New England vince since these have not been associated with any specific geologic structures or faults. An stigation is currently in progress to study the Moodus noises. However the noises have not n associated with specific faults.

nsity V (MM). The largest earthquake in this province was an Intensity VI (MM) event which urred in 1904 east of Eastport, Maine.

Atlantic Coastal Plain Province has experienced a number of minor earthquakes throughout historic record. Exclusive of the Charleston, South Carolina area, the largest events have been ntensity VII (MM). These occurred in 1871, 1884, and 1927 near the boundary with the New land and Piedmont Provinces in northern New Jersey and near New York City.

Piedmont-Blue Ridge Province exhibits a fairly low level of seismicity throughout its length h diffuse areas of higher activity in central Virginia and western South Carolina. The largest orical earthquake in the province was of Intensity VII (MM). It occurred in central Virginia in 5.

2.4 MAXIMUM EARTHQUAKE POTENTIAL maximum earthquake potential for the site is evaluated by utilizing maximum earthquakes ciated with all nearby tectonic provinces and geologic structures. This analysis is made for different sets of conditions. First, actual site intensities resulting from larger historical hquakes are determined. Second, the maximum potential site intensities resulting from othetical events are calculated. These hypothetical events are specified as the largest known hquakes in each adjoining tectonic province. Each is postulated to occur at the point where its vince or structure most closely approaches the site.

2.4.1 Maximum Historical Site Intensity etailed analysis of large historical earthquakes in the northeastern United States indicates ction 2.5.2.1.4) that four earthquakes have been felt with intensities of V (MM) or greater at site. The 1755 Cape Ann earthquake caused damage corresponding to Intensity V-VI (MM) at ns near the site. The East Haddam-Moodus earthquake of 1791 was reportedly felt strongly no damage resulted at such localities as Hartford and New London, indicating an intensity of roximately V (MM). A similar intensity value is indicated for the Millstone site. Data ected by Rockwood indicate that the 1884 earthquake, with an epicenter approximately in the w York City area, was felt at the site with a probable intensity of V (MM). Bricks were thrown m chimneys and a few walls were cracked at New Haven, and plaster was cracked and odged at New London. The 1737 earthquake with epicentral location also in the New York area appears similar to the 1884 earthquake and may have been felt with an intensity of V at site.

clear that these four earthquakes in the site region caused Intensity V or V-VI (MM) at the

. The epicentral intensity of these four earthquakes was either VII, VI-VII, or VIII (MM). In site region, the 1755 Cape Ann earthquake was of highest intensity (VIII (MM)). Earthquakes er than the 1755 Cape Ann, for example, have all occurred outside the site region in the albaie area of the St. Lawrence River Valley. Large earthquakes in this zone are estimated to e caused Intensity IV-V (MM) at the site. The 1886 Charleston earthquake of Intensity X

2.4.2 Maximum Earthquake Potential from Tectonic Province Approach account for the possibility of large errors in epicentral determination, especially for events urring prior to 1950 and in the absence of capable faults, the largest known earthquake in each vince was attenuated to the site from points of nearest approach of the tectonic province in ch the earthquakes occurred, using the conservative attenuation relationship of Howell and ultz (1975). Justification for this procedure is that individual epicenters are not properly ted and, therefore, cannot be associated with specific structures.

site is located in the Southeastern New England-Maritime Tectonic Province. The largest hquake in this province was of Intensity VI (MM). The New England Tectonic Province is y near the site and several earthquakes of Intensity VII (MM) have occurred in this province 68 and 1791 at Moodus and 1737 and 1884 at New York City). Assuming that these hquakes occur at the nearest approach point of the New England Province to the site (20 km),

nsity at the site would be VII (MM). The Coastal Plain Province is also close to the site (about km). The 1927 earthquake near Asbury Park, New Jersey, was in the Coastal Plain Province had an epicentral intensity of VII (MM). A similar earthquake in the Coastal Plain Province r the site would cause Intensity VII (MM) at the site. Only one earthquake of Intensity VIII M) is associated with any of the provinces or structures in the site region. This earthquake urred near Cape Ann, Massachusetts, in the White Mountains Plutonic Province. Such an hquake occurring in that province at a minimum distance from the site (170 km) would cause intensity of V-VI (MM). In other tectonic provinces in the site region, the maximum intensity arthquakes was VII (MM). Therefore, the effect of these earthquakes would be less than VII M).

he eastern United States, earthquakes with intensities greater than VIII (MM) have occurred y in LaMalbaie, Quebec; Charleston, S.C.; and New Madrid, Missouri. Earthquake activity at e places is assumed to be associated with specific structures and, based on historical data, ld not cause greater effects at the site than Intensity IV-V (MM). Therefore, the maximum hquake potential at the site due to earthquakes occurring within 10 to 20 km of the site is nsity VII (MM).

2.5 SEISMIC WAVE TRANSMISSION CHARACTERISTICS OF THE SITE perties of subsurface materials at the site are discussed in detail in Section 2.5.4. The pressional and shear wave velocities of in situ materials are tabulated in Section 2.5.4.4.3 and er properties of the in situ materials are described in Section 2.5.4.2. The groundwater ditions at the site are discussed in Section 2.5.4.6.

safe shutdown earthquake (SSE) value of 0.17 g is applied to the bedrock surface. For ctures founded on soils, the effect of the overburden on the earthquake motion has been sidered in soil-structure interaction computations, as discussed in Section 3.7B.2.4.

discussed in Section 2.5.2.4, the maximum earthquake potential at the site is an Intensity VII nt occurring 10 to 20 km from the site. Murphy and O'Brien (1977) have published an analysis cceleration-intensity correlations using a new worldwide data base and a variety of statistical dels. Their correlation equation relating Intensity I (MM) and peak horizontal ground eleration (Ah) is:

log Ah = 0.25 I + 0.25 re Ah is in cm/sec2. For a Modified Mercalli Intensity VII earthquake, this equation gives an rage horizontal component peak acceleration of 0.10 g. In order to be conservative in the lstone 3 plant design, the SSE is specified as 0.17 g. The duration of strong ground motion ciated with an Intensity VII earthquake is estimated at 6 seconds using an assumed threshold eleration value of 0.05 g according to Bolt (1973).

2.7 OPERATING BASIS EARTHQUAKE tudy of the earthquake history of the site region has shown that the maximum historical nsity at the site has been V-VI (MM), corresponding to a peak horizontal ground acceleration 0.05 g (Murphy and O'Brien 1977). In accordance with 10 CFR 100, Appendix A, the rating basis earthquake is taken to be at least one half of the SSE, or 0.09 g.

2.8 REFERENCES

FOR SECTION 2.5.2 2.1-1 Aggarwal, Y. P. and Sykes, L. R. 1978. Earthquakes, Faults and Nuclear Power Plants in Southern New York and Northern New Jersey. Science, Vol 200, p 425-429.

2.1-2 Bolt, B. A. 1973. Duration of Strong Ground Motion. Proceedings of the Fifth World Conference on Earthquake Engineering, Rome, Italy, Vol 1, p 1304-1308.

2.1-3 Boston Edison Company 1976a. Summary Report - Geologic and Seismologic Investigations. Pilgrim Unit 2, USNRC Docket No. 50-471. Boston, Mass.

2.1-4 Boston Edison Company 1976b, Historical Siesinicity of New England. Pilgrim Unit 2, USNRC Docket No. 50-471.

2.1-5 Brigham, W. J. 1871. Volcanic Manifestations in New England. Memories of the Boston Society of Natural History, Vol 2, p 1-28.

2.1-6 Brooks, J. E., S. J. 1960. A Study in Seismicity and Structural Geology, Part II -

Earthquakes of Northeastern United States and Eastern Canada. Obs. Geophys.

College Jean-de-Brebeuf, Bull. Geophys., No. 7, 12-40.

2.1-8 Chiburis, E. C. 1979. Seismicity of New England. (In press).

2.1-9 Coffman, J. L., and Von Hake, C. A. 1973. Earthquake History of the United States.

Publication 41-1, U.S. Dept. of Commerce, Supt. of Documents, Washington, D.C.

2.1-10 Crowell, R. D. D. 1868. History of the Town of Essex from 1634-1868. Town Press of Samuel Bowles and Company, Springfield, Mass., p 143-144.

2.1-11 Felt, J. D. 1899. Annals of Salem, Boston. James Munroe & Company, Boston, Mass.

2.1-12 Hadley, J. B. and Devine, J. F. 1974. Seismotectonic Map of the United States.

USGS Miscellaneous Field Studies, Map MF-620.

2.1-13 Howell, B. F. and Schultz, T. R. 1975. Attenuation of Modified Mercalli Intensity with Distance from the Epicenter. Bulletin of the Seismological Society of America, Vol 65, No. 3, p 651-666.

2.1-14 Leblanc, G. and Buchbinder, G. 1977. Second Microearthquake Survey of the St.

Lawrence Valley near LaMalbaie, Quebec. Canadian Journal of Earth Sciences, Vol 14, No. 12, p 2778-2789.

2.1-15 Linehan, D. 1964. Report on the Seismicity of the East Haddam-Moodus Area of Connecticut. Prepared for Stone & Webster Engineering Corporation by Weston Geophysical Research, Inc., Westboro, Mass.

2.1-16 Murphy, J. R. and O'Brien, L. J. 1977. The Correlation of Peak Ground Acceleration Amplitude with Seismic Intensity and Other Physical Parameters. Bulletin of the Seismological Society of America, Vol 67, No. 3, p 877-915.

2.1-17 New York State Electric and Gas Corporation 1978. Preliminary Safety Analysis Report. Amendment 2, New Haven Units 1 and 2, Docket No. STN50-506 and STN50-507.

2.1-18 Page, R. A.; Molnar, P. H.; and Oliver, J. 1968. Seismicity in the Vicinity of the Ramapo Fault, New Jersey-New York. Bulletin of the Seismological Society of America, Vol 68, No. 2, p 681-688.

2.1-19 Perley, S. 1891. Historic Storms of New England. Salem Press Publishing and Printing Company, Salem, Mass.

2.1-20 Rockwood, C. G., Jr. 1885. Notices of Recent Earthquakes. American Journal of Science and Arts, Third Series, Vol 29, p 425.

2.1-22 Sbar, M. L. and Sykes, L. R. 1973. Contemporary Compressive Stress and Seismicity in Eastern United States. Bulletin of the Geological Society of America, Vol 84, p 1861-1882.

2.1-23 Sbar, M. L. and Sykes, L. R. 1977. Seismicity and Lithospheric Stress in New York and Adjacent Areas. Journal of Geophysical Research, Vol 82, p 5771-5786.

2.1-24 Skehan, J. W. 1973. Subduction Zone between the Paleo-American and Paleo-African Plates in New England. Geofisica International (Mexico), Vol 13, No. 4, p 291-308.

2.1-25 Smith, W. E. T. 1966. Earthquakes of Eastern Canada and Adjacent Areas, 1928-1959. Dom. Observ. Publ., Vol 32, p 87-121.

2.1-26 Street, R. L. and Turcotte, F. T. 1977. A Study of Northeastern North American Spectral Moments, Magnitudes and Intensities. Bulletin of the Seismological Society of America, Vol 67, No. 3, p 599-614.

2.1-27 The Day 1884. New London, Conn., August 11.

2.1-28 United States Earthquakes 1940. U.S. Dept. of Commerce, U.S. Coast and Geodetic Survey, Washington, D.C.

2.1-29 U.S. Nuclear Regulatory Commission 1977. Atomic Safety and Licensing Appeal Board. 6NRC547 (1977), Indian Point Units 1, 2, and 3, Docket No. 50-3, 50-247, 50-286.

2.1-30 U.S. Nuclear Regulatory Commission 1978. Safety Evaluation Report, Erie Power Station, Docket No. 50-580, 50-581.

2.1-31 Wetmiller, R. J. 1975. The Quebec-Marine Border Earthquake, 15 June 1973.

Canadian Journal of Earth Sciences, Vol 12, p 1917-1928.

2.1-32 Winthrop, J. 1757. An Account of the Earthquake Felt in New England and the Neighboring Parts of America on the 18th of November 1755. Philosophical Transactions, Vol 50, Part 1, p 1-18.

TABLE 2.5.2-1 MODIFIED MERCALLI (MM) INTENSITY SCALE OF 1931 CLICK HERE TO SEE TABLE 2.5.2-1

TABLE 2.5.2-2 LIST OF OPERATING SEISMIC STATIONS CLICK HERE TO SEE TABLE 2.5.2-2

TABLE 2.5.2-3 CHRONOLOGICAL CATALOG OF EARTHQUAKE ACTIVITY WITHIN 200 MILES OF THE SITE CLICK HERE TO SEE TABLE 2.5.2-3

TABLE 2.5.2-4 LIST OF EARTHQUAKES WITHIN THE 50-MILE RADIUS CLICK HERE TO SEE TABLE 2.5.2-4

FIGURE 2.5.2-1 LOCATION OF SEISMIC STATIONS FIGURE 2.5.2-2 EPICENTERS OF EARTHQUAKES WITHIN 200-MILE RADIUS FIGURE 2.5.2-3 LOCATION OF EARTHQUAKES WITHIN THE 50-MILE RADIUS FIGURE 2.5.2-4 ISOSEISMAL MAP, EARTHQUAKE OF NOVEMBER 9, 1727 FIGURE 2.5.2-5 ISOSEISMAL MAP, EARTHQUAKE OF NOVEMBER 18, 1755 FIGURE 2.5.2-6 ISOSEISMAL MAP, EARTHQUAKE OF MAY 16, 1791 FIGURE 2.5.2-7 ISOSEISMAL MAP, EARTHQUAKE OF AUGUST 10, 1884 FIGURE 2.5.2-8 ISOSEISMAL MAP, EARTHQUAKE OF MARCH 1, 1925 (FEBRUARY 28, 1925 EST)

IGURE 2.5.2-9 ISOSEISMAL MAP, EARTHQUAKES OF DECEMBER 20 AND 24, 1940

FIGURE 2.5.2-10 TECTONIC PROVINCES e of the published geology maps show faults in the vicinity of the site. Figure 2.5.1-13 shows mposite bedrock geologic map for the area surrounding the site. The closest mapped fault to site is in the Uncasville quadrangle, 10.5 miles northeast of the Millstone site (Goldsmith 7a). Faulting has also been observed in the Clinton quadrangle, approximately 17 miles west he site, and in the Moodus and Colchester quadrangles, approximately 15 miles north of the (Lundgren et al., 1971; Lundgren and Thurrell 1973). These faults are all believed to be high-le faults related to extension tectonics of Late Triassic-Jurassic time (Lundgren et al., 1971; dgren and Thurrell 1973; Goldsmith 1973).

y-two faults were found during the mapping of the rock excavation for Millstone 3 between 1979 and July 1982. Forty of the faults have apparent displacements equal to or less than one with the remaining faults exhibiting apparent displacements greater than one foot. The extent he areas mapped shows eleven separate fault zones with numerous minor associated faults.

ure 2.5.1-18 shows the general location of these faults. Table 2.5.3-1 lists the faults mapped at site and provides a reference for those faults discussed in previous reports (NNECo. 1975; 6; 1977; 1982).

ples from the gouge zone of faults T-2, T-3, 1541, and 2819 were taken at final excavation de in the containment structure and discharge tunnel excavations. Petrographic analyses, x-ray raction studies, and potassium-argon radiometric dating were performed on these samples.

ay diffraction studies were performed on material from faults 1940, 2282, 2339, and 2781 ch indicated that the material was not suitable for age dating. The results of these tests are ussed in detail in Section 2.5.3.2. Table 2.5.3-2 describes the samples and shows the tests ormed. The analyses and tests show excellent agreement with previous studies performed at site (NNECo. 1975; 1976; 1977).

3.1 GEOLOGIC CONDITIONS OF THE SITE tion 2.5.1.2 discusses the stratigraphy, structural geology, and geologic history of the site area etail. The bedrock geologic map and cross section of the site area and the tectonic setting of ern Connecticut are shown on Figures 2.5.1-13 and 2.5.1-14, respectively.

3.2 EVIDENCE OF FAULT OFFSET published geologic maps which include the site area do not indicate the presence of faulting.

tudy of LANDSAT photographs (Figure 2.5.1-9) of southern New England identifies ineaments greater than 10 miles long. None falls within the 5-mile radius of the site.

ure 2.5.1-10 shows the lineaments and Section 2.5.1.1.4.4 discusses them.

umber of small faults were uncovered at the site during excavation and were mapped in detail.

larger faults were observed and mapped both at top of rock and at final excavation grade. One t (508) (NNECo. 1975) was mapped at top of rock and not observed at final grade; others nd at final grade were not observed at the rock surface. Figure 2.5.1-18 shows all of the faults overed during the mapping at the site. The larger faults exhibiting brecciated and silicified

ven fault zones (T-1, T-2, T-3, 18, 471-1541, 1599, 1940, 2250, 2282-2295, 2339-2347, and

0) have been found in the main site area and pumphouse excavations. Figure 2.5.1-18 also ws the remaining ancillary faults. Two of the smaller faults, 508 and 368, terminate within the ts of the main site excavation. Fault 508 is the only fault that was mapped at top of rock that not noted at final grade. The other faults extend beyond the boundary of the excavation at t in one direction. Fault 1541 in the auxiliary building was mapped as fault 461 in the tainment excavation. Displacement along this fault dies out before intersecting the thwestern wall of the containment.

st of the faults trend to the north and dip at high angles either to the east or to the west.

le 2.5.3-1 lists their characteristics. Slickenside information (Figure 2.5.1-17) indicates that sense of movement was in an east-west direction (dip slip). Slickenside information in the T-2,

, and 2339 fault zones indicates that the motion along the fault was oblique. Exposures of the ts (T-2, 18, and 1541) in the excavation walls indicate that they are normal (gravity) faults.

refore, the oblique motion along the larger faults has a greater dip slip component.

o of the larger faults, T-2 and T-3, were previously studied in detail immediately after their overy during the mapping of the bedrock surface (NNECo. 1975). Figures 2.5.3-1 through 3-3 show the detailed maps of these faults at final excavation grade. Both faults are racterized by a zone of gouge, breccia, microbreccia, and cataclasite derived from the Monson iss and igneous rocks which intrude the Monson Gneiss. Hydrothermal fluids have permeated gouge zones of these faults. Free-growing crystalline quartz was found in the T-2 zone, and sy quartz coated the fracture surfaces and vugs in the breccias and cataclasite of the T-3 fault

e. Drusy quartz was also found in open cavities adjacent to T-2.

brecciated zone of T-2 varies in thickness from 4 to 6 inches. However, in some areas the e widens to 1.5 feet, and in others narrows to a single, nearly clean fracture. For the most part, breccia is partially to completely rehealed. The clay gouge varies in thickness along the fault e although it rarely exceeds 1.0 inch. The T-3 brecciated zone is similar to that of T-2, except imensions. The fault zone varies in thickness from 6 inches to 2 feet, and the clay gouge cally forms a thin, 0.5 to 2 inch, continuous seam. It is occasionally found as a thin filling ween brecciated blocks. Both zones are moderately to severely weathered with much of the stained by iron oxide.

lt T-2 trends N15W, dips at 70 degrees to the east, and is located on the eastern side of the tainment excavation. The geologic maps of the walls of the containment and of the discharge nel, Figures 2.5.4-11 through 2.5.4-14 and 2.5.4-3 through 2.5.4-5, respectively, show a ion across the fault in four locations. The largest fault at the site, T-3, lies on the western edge he rock exposure in the excavation. T-3 strikes N28W and dips 70 degrees to the east.

le 2.5.3-1 shows the apparent displacements of the faults in the horizontal plane and lists the ulated displacements, determined from the offset pegmatite veins and from slickenside rmation. The eastern blocks of T-3, T-2, 1599, and most of the faults in the pumphouse appear

omplex irregular pegmatitic intrusion has obscured the contacts in the vicinity of faults 2250 2282 making it impossible to determine the sense of development.

lt 1940 shows low-angle thrust displacement of between 1.0 and 2.0 inches toward the heast. The southwest dipping fault zone consists of a zone of weathered and fractured rock clay varying from less than 1.0 inch to about 10 inches thick. The fault ends at joint 198 but is lleled by a similar zone about 3 feet below it. This parallel zone crosses joint 198 but ends at t T-2 in a southwesterly direction. Projection of 1940 updip places the intersection of the fault h the rock surface in the vicinity of the demineralized water storage tank. Geologic mapping of area did not reveal the trace of the fault at the surface. Hydrothermal activity along the fault is ent by the presence of smectite clay in the gouge which is probably related to the same period ydrothermal activity shown in the high angle faults at the site.

r separate fault zones were uncovered in the pumphouse excavation (2250, 2282, 2330 plus 7, and 2380) with smaller faults splaying from these zones, as shown by Figures 2.5.1-18 and 4-8. These faults are similar in trend, fault zone composition, and amount and type of lacement to those faults uncovered in the main excavation. The shear zones of the faults in the phouse were characterized by hydrothermal quartz. Clay gouge was generally restricted to y thin coatings on fracture surfaces.

r other faults (2781, 2817, 2818, and 2819) were found in the discharge tunnel excavation and included in Figure 2.5.1-18 and in Figures 2.5.4-19 through 2.5.4-22. A separate report has n submitted detailing the investigation of these faults (NNECo. 1982).

lt 2781 dips 45 degrees to the west and shows reverse displacement of a biotite seam of 2.5 es. Clay from the 0- to 4-inch thick fault zone was found unsuitable for age dating. Till and wash directly overlying the fault was examined and found to be not disturbed. The largest fault overed in this portion of the discharge tunnel consists of three related faults, numbers 2817, 8, and 2819. Offset of pegmatite veins up to 1.5 feet were observed across 2817 and 2818, reas no continuity could be determined across 2819 in the width of the excavation. Fault ge material from 2819 produced a K/Ar age date of 142 million 6 million years. The zone was d with undisturbed drusy quartz and also showed no disruption of overlying stratified and tratified glacial deposits. Faults 2894 and 2899 (NNECo. 1982) show 4-inch and 0.5-inch lacements, respectively, on very narrow fault zones. Displacements on both faults were erved to end within the excavation.

3.2.1 Petrographic Analysis samples were taken from the T-2 and T-3 fault zones at final excavation grade to determine geologic history of the faulting. Figures 2.5.3-1 through 2.5.3-3 show the location of these ples. Table 2.5.3-2 lists the samples and gives a general description of each.

endix 2.5B includes a report on the petrographic analyses performed by Dr. Reinhard A.

bus of Williams College, Williamstown, Massachusetts. The work described herein

ographic analyses of the samples indicate that the fault zones have undergone at least one od of deformation, and possibly more. The cataclasite samples (2F, 5F, 6F, 9F, and 11F) sist mainly of a very fine-grained matrix of subhedral quartz prisms. For the most part, these ms exhibit no preferred orientation. Chlorite is also common in the matrix, along with some mose muscovite. The remainder of the cataclasite is made up of quartz, plagioclase, and mica ments. The fragments indicate that large pieces have undergone some deformation. The rtz crystals are highly strained and the plagioclase twin lamellae have been deformed. All of larger fragments have been altered and chlorite is present between many of the crystals.

orite has replaced the plagioclase in many places, and, where it has not been replaced, the ioclase has been altered to a highly-birefringent clay (Appendix 2.5B).

ple 12F is a sample of the Monson Gneiss taken adjacent to the T-3 fault zone. Hand cimens of the gneiss appear to be sheared. The analysis indicates that quartz present in the thin ion is very highly strained and that the plagioclase has been altered to highly birefringent clay.

bus (Appendix 2.5B) classifies this as an altered biotite-quartz-andesine gneiss.

petrographic analysis by Wobus (Appendix 2.5B) indicates that the material from the two erent fault zones, T-2 and T-3, is similar. He has classified the material in the zones as rothermally altered and silicified cataclasite. Samples taken from the bedrock surface ping also indicate the same results (NNECo. 1975).

geologic history inferred from the petrographic study is as follows:

1. Formation of a breccia and cataclasite from faulting of Monson Gneiss and the pegmatites.

2. The injection of hydrothermal fluids producing a matrix of subhedral quartz, and altering the original breccia to produce a highly birefringent clay.

3. Fracturing and granulation of the crystallized quartz matrix.

4. Continuation of hydrothermal activity resulting in the development of chlorite and plumose muscovite in the cracks and fractures.

5. Weathering effects, varying with the degree of silicification.

3.2.2 Clay Mineralogy, Fluid Inclusion Analysis, and Radiometric Dating ples of the clay gouge in the fault zones were taken at final excavation grade. Table 2.5.3-2 these samples, their location, and the tests performed. Six samples were analyzed by x-ray raction and radiometrically dated using the potassium-argon (K/Ar) method. Five of the ples (7F, 10F, 13F, 14F, and 15F) were taken from the larger T-2 and T-3 fault zones. Sample was taken from a small fault shown as 1541-461 on Figures 2.5.1-18 and 2.5.4-6. The

samples were analyzed to determine their composition by x-ray diffraction techniques prior eing radiometrically dated. Dr. R. T. Martin of the Massachusetts Institute of Technology, bridge, Massachusetts performed these analyses. His report is included as Appendix 2.5C.

r studies made by Dr. Martin on clay gouge materials have been reported in detail in Geologic pping of the Bedrock Surface (NNECo. 1975) and Report on Small Fault in Warehouse 5 -

lstone 2 and Condensate Polishing Facility (NNECo. 1976).

samples were comprised mainly of quartz and clay. Feldspar is noted in three of the samples 13F, and 14F); however, the amount is small enough to have no effect on the age determined K/Ar methods. The clay portion of the gouge consists of smectite, chlorite, and illite.

1Md, 1M, and 2M polymorphs are the mica polymorphs (illite) of the clay size fraction. The tive amounts of the polymorphs are summarized below from Dr. Martin's report pendix 2.5C):

1F 7F 10F 13F 14F 15F 2M 0 0.12 0 0 0 0 1M 0 0.13 0.42 0.22 0.20 0.42 1M 0.17 0.28 0.09 0.24 0.18 0 mplete loss of argon is possible as a result of intense cataclastic deformation (Sutter 1971).

ns and Snellenburg (1971) have previously performed K/Ar dating of illite gouge and have cated that the 1Md mica polymorphs are developed at the time of faulting and are authigenic.

1Md polymorph is a low temperature mineral. Both the 1Md and the 1M polymorphs appear e metastable, even at low temperatures (Velde 1965). With increasing temperature, the 1Md,

, 2M reaction takes place (Yoder and Eugster 1955). The temperature necessary for the ation of the reaction from 1Md to 1M at low pressures is no greater than 250C (Velde 1965).

rtz crystals found in the brecciated zones of T-2 and T-3 at the bedrock surface were tested to rmine their temperature of formation by Dr. Earl Ingerson of the University of Texas at Austin ECo. 1975). The temperature range for the hydrothermal formation of these quartz crystals is C to 198C. This information, together with Dr. Martin's analysis indicating the relative unts of the mica polymorphs, infers that some of the 1Md polymorphs may have reverted to 1M polymorph. Apparently, the hydrothermal activity was not intense enough or long enough omplete the reaction.

2M polymorph was noted in only one sample, 7F. Because it appears in only one sample, it ms unlikely that the 2M polymorph is caused by the completion of the reaction. The 2M ymorph is common in most igneous and metamorphic rocks (Velde 1965). Since both rock es are involved in the faulting at Millstone, the 2M polymorph in Sample 7F may be a

chron Laboratories, Cambridge, Massachusetts, dated the samples analyzed by Dr. Martin.

results of the potassium-argon testing performed by Geochron Laboratories on samples from l excavation grade are included in Appendix 2.5D and are summarized in Table 2.5.3-3. The ples ranged in age from 109 to 200 m.y.a. Three samples from T-3 (10F, 13F, and 15F) were lyzed and yielded dates of 1827, 1556, and 1787 m.y.a. Dates of 2007 and 1656 m.y.a.

e obtained on samples taken from T-2 (7F and 14F). Sample 1F was taken from a smaller t, 1541. The age indicated by the K/Ar method for this sample was 1095 m.y.a.

of the samples tested yield results that are consistent with previous tests performed on samples m Millstone, with the exception of 1F. Table 2.5.3-3 lists the dates of samples previously ed at Millstone. These samples had a range of ages between 168 to 198 m.y.a. Excluding the from Sample 1F, the average age of faulting from all tests performed on the clay gouge from Millstone site is 176 m.y.a.

date on Sample 1F is considerably lower than the other dates. Compared to the other samples n at final grade, this sample had considerably smaller amounts of the illite fraction pendix 2.5C), and a higher ratio of smectite to illite. The smectite may have formed after the ge material, due to weathering, hydration of the illite, or by hydrothermal alteration. The nger date may reflect the interference of the smectite portion of the sample. As mentioned in tion 2.5.3.2.1, hydrothermal alteration is quite prominent, and the fault zone has been uenced by weathering.

e samples of gouge were taken from fault 1940 in the engineered safety features building and ts 2282 and 2339 in the Millstone 3 pumphouse. Dr. R. C. Reynolds of Dartmouth College lyzed the clay mineralogy of these samples. His reports are included as Appendix 2.5E.

ge amounts of smectite and little illite were present in the samples (B, C, and D) from fault 0 which precluded K/Ar dating of the material. Samples P-1 and P-2, taken from faults 2282 2339, respectively, were composed mostly of kaolinite with a small percentage of ntmorillinite (Appendix 2.5E). A trace of illite was noticed in sample P-2 but neither sample ld be dated.

form and quantity of the smectite present in the samples from fault 1940 does, however, cate a probable hydrothermal origin for the material. The kaolinite from the faults in the phouse (P-1 and P-2) was found to have a crystalline structure, also indicative of a rothermal origin. The date of the last hydrothermal event, as indicated by the studies of faults, and T-3, is between 168 and 198 m.y.a.

y gouge samples from faults 2781 and 2819 (NNECo. 1982) in the discharge tunnel were also lyzed by Dr. R. C. Reynolds. His study indicated the material from fault 2781 was not suitable age dating, as it comprised mostly original micas from the parent rock. The material from 9 was found to contain sufficient authigenic illite and was suitable for age dating. It produced

/Ar age date of 142 million +1-6 million years.

K/Ar age dating, petrographic analysis, x-ray diffraction studies, soils mapping, and the iled mapping of the fault zones indicate that the faults at the Millstone site are incapable ures. The petrographic analysis shows that the cataclasite has been silicified and rothermally altered, and that the fractures and cracks have been filled with chlorite. Prismatic rtz crystals, drusy quartz, and the silicified cataclasite found in the fault zones would be tured and/or granulated if any additional movement had occurred.

radiometric age dates on the fault gouge indicate that the last activity along the faults urred approximately 142 m.y.a. Silicified breccias, microbreccias, and cataclasites within the and T-3 zones indicate that earlier episodes of movement and silicification occurred. The ence of the 1M mica polymorph indicates that the unordered 1Md has undergone changes ated by the heat associated with the introduction of hydrothermal fluids along the fault zones.

tabulation in Section 2.5.3.2.2 summarizes the relative amounts of polymorphs from the y diffraction analysis reported in Appendix 2.5C. It was found that the clay gouge is prised mainly of 1M and 1Md polymorphs. Therefore, the dates obtained by radiometric lysis indicate some hydrothermal heating of the clay gouge zone - the last activity along the ts.

petrographic and radiometric studies are reinforced by the published geologic history of the on (Section 2.5.1.1.5) and of the site area (Section 2.5.1.2.4.1). Detailed mapping of the avation showed that the most prominent joint set trends northerly and dips at high angles to the or west, as shown on Figure 2.5.1-16. All of the smaller faults parallel the prominent ting, indicating that the same tectonic forces were responsible for their formation. Slickenside rmation (Figure 2.5.1-17) and exposures in the excavation indicate that the major component movement is down-dip. Regionally, a prominent northerly joint set exists. Many of these aces also exhibit slickensides (Lundgren et al., 1971; Lundgren and Thurrell 1973). West of site, the Triassic-Jurassic Basin is bordered by a northerly trending, high angle fault (Rodgers 0). The Clinton quadrangle to the west and the Moodus and Colchester quadrangles to the h of the site are cut by numerous high-angle faults related to the major Triassic faults to the t (Lundgren et al., 1971; Lundgren and Thurrell 1973). All available information indicates the forces necessary to develop most of the jointing and faulting at Millstone Point are related he extensional regime of the Juro-Triassic period. The compressional forces evident by faults 0 and 2781 may have resulted from shear couples associated with the tensional forces or may e been the result of pre-Triassic tectonism during the Allegheny Orogeny. Hydrothermal vity along the faults represents the youngest known fault-related event in southern New land (Goldsmith 1973; Skehan 1975; Rodgers 1975).

lstone Point, like much of New England, is covered by a layer of glacial till. The till has been erved to overlie several faults at the site. No disturbance of the till has been noted (NNECo, 5, 1982). Caldwell (Appendix 2.5A) estimated the age of the till at the site to be roximately 18,000 years old. Flint (1975) estimates that the margin of the glacier had melted k to the line of the present Connecticut coast about 15,000 years ago.

faulting at the site is related to the Triassic-Jurassic rifting as stated in Section 2.5.1.1.4.2 or r events as in the case of fault 1940.

3.3 EARTHQUAKES ASSOCIATED WITH CAPABLE FAULTS re is no evidence of capable faults within the 5-mile radius of the site. As stated in tion 2.5.2.3.1, the majority of the significant seismic activity has been associated with the ite Mountain Plutonic Province. Some activity has been associated with the Ramapo fault em (Aggarwal and Sykes 1978); however, the fault is not considered capable (NRC 1977).

3.4 INVESTIGATION OF CAPABLE FAULTS re are no capable faults within the site area. The faults uncovered in the excavation are ussed in Section 2.5.3.2.

3.5 CORRELATION OF EPICENTERS WITH CAPABLE FAULTS discussed in Section 2.5.2.3.2, there has been no spatial correlation between earthquakes and ts in the site region. Some correlation has been suggested with the Ramapo fault in New York New Jersey. As discussed in Section 2.5.2.3.1, however, the Ramapo is not considered able (NRC 1977).

3.6 DESCRIPTION

OF CAPABLE FAULTS re are no capable faults within 5 miles of the site.

3.7 ZONE REQUIRING DETAILED FAULTING INVESTIGATION ven incapable fault zones have been uncovered during excavation at the site. These faults have n mapped in detail and are discussed in Section 2.5.3.2. Figure 2.5.4-6 shows the map of the rs of structures. There are no other zones requiring detailed investigation.

3.8 RESULTS OF FAULTING INVESTIGATION re is no evidence of capable faulting within the 5-mile radius of the site. The faults at the site related to the rifting associated with the Triassic-Jurassic Period or older, with the last activity urring approximately 142 m.y.a.

3.9 REFERENCES

FOR SECTION 2.5.3 3.1-1 Aggarwal Y. P. and Sykes, L. R. 1978. Earthquakes, Faults, and Nuclear Power Plants in Southern New York and Northern New Jersey. Science, Vol. 200, No.

4340, p 425-429.

3.1-3 Goldsmith, R. 1967a. Bedrock Geologic Map of New London Quadrangle, Connecticut. U.S. Geological Survey, Quadrangle Map GQ 574, Washington, D.C.

3.1-4 Goldsmith, R. 1973. Oral Communication with L. Martin and D. Carnes, Stone &

Webster Engineering Corp., Boston, Mass.

3.1-5 Lundgren, L., Jr.; Ashmead L.; and Snyder, G. L. 1971. The Bedrock Geology of the Moodus and Colchester Quadrangles. State Geological and Natural History Survey, Quadrangle Report No. 27.

3.1-6 Lundgren, L., Jr. and Thurrell, R. F. 1973. The Bedrock Geology of the Clinton Quadrangle. State Geological and Natural History Survey of Connecticut, Quadrangle Report No. 29.

3.1-7 Lyons, J. B. and Snellenberg, J. 1971. Dating Faults. Geological Soc. Amer., Bull.

82, p 1749 1752.

3.1-8 Northeast Nuclear Energy Co. (NNECo.) 1975. Geologic Mapping of Bedrock Surface, Millstone Nuclear Power Station Unit 3. NRC Docket No. 50-423, Hartford, Conn.

3.1-9 Northeast Nuclear Energy Co. (NNECo.) 1976. Report on Small Fault Uncovered in Warehouse No. 5 Unit 2 and Condensate Polishing Facility, Millstone Nuclear Power Station Unit 3. NRC Docket No. 50-423, Hartford, Conn.

3.1-10 Northeast Nuclear Energy Co. (NNECo.) 1977. Fault in the Demineralized and Refueling Water Tank Area, Millstone Nuclear Power Station Unit 3. NRC Docket No. 50-423, Hartford, Conn.

3.1-11 Northeast Nuclear Energy Co. (NNECo.), 1982, Report on Faults and Soil Features Mapped in the Discharge Tunnel Excavation, Millstone Nuclear Power Station -

Unit 3, NRC Docket No. 50-423.

3.1-12 Nuclear Regulatory Commission 1977. 6 NRC 547(1977) Atomic Safety and Licensing Appeal Board Hearings on Indian Point, Units 1, 2, and 3 (Dockets No.

50-3, 50-247), (50-286) ALAB-436.

3.1-13 Rodgers, J. 1970. The Tectonics of the Appalachians. John Wiley and Sons, Inc.,

New York, NY.

3.1-14 Rodgers, J. 1975. Oral Communication with L. Martin and P. Mayrose, Stone &

Webster Engineering Corp., Boston, Mass.

3.1-16 Skehan, J. W. 1961. The Green Mountain Anticlinorium in the Vicinity of Wilmington and Woodford, Vermont. Vermont Development Department, Bull. No.

17, Montpelier, Vt.

3.1-17 Suter, R.; deLaguna, W.; and Perlmutter, N. M. 1949. Mapping of Geologic Formations and Aquifers of Long Island, New York. New York Dept. of Conservation, Water Power and Control, Conn. Bull. GW-18, p 212, Albany, NY.

3.1-18 Sutter, J. F. 1971. K-Ar Relationships in Mylonite Rocks (Abs). A.G.U. Trans., Vol.

52, p. 367-368.

3.1-19 Velde, B. 1965. Experimental Determination of Muscovite Polymorph Stabilities, Amer. Mineral., Vol. 50, p. 436-449.

3.1-20 Yoder, H. S. and Eugster, H. P. 1955. Synthetic and Natural Muscovites, Geochim et Cosmochim Acta, Vol. 8, p. 225-280.

TABLE 2.5.3-1 LIST OF FAULTS CLICK HERE TO SEE TABLE 2.5.3-1

TABLE 2.5.3-2 LIST OF SAMPLES CLICK HERE TO SEE TABLE 2.5.3-2

TABLE 2.5.3-3 LIST OF K/AR AGE DETERMINATIONS OF FAULT GOUGE CLICK HERE TO SEE TABLE 2.5.3-3

FIGURE 2.5.3-1 T-2 FAULT ZONE, FINAL EXCAVATION GRADE - NORTHERN SECTION Revision 3606/29/23 MPS-3 FSAR 2.5.3-14

FIGURE 2.5.3-2 T-2 FAULT ZONE, FINAL EXCAVATION GRADE - SOUTHERN SECTION Revision 3606/29/23 MPS-3 FSAR 2.5.3-15

FIGURE 2.5.3-3 T-3 FAULT ZONE, FINAL EXCAVATION GRADE Revision 3606/29/23 MPS-3 FSAR 2.5.3-16

stability of the soil and rock underlying the Millstone Nuclear Power Station - Unit 3 ndations was evaluated using the results of detailed field and laboratory investigations, both r to and during construction. The field investigations consisted of borings, standard etration tests, piezometer installations, water pressure tests, geologic mapping, and seismic eys to determine compressional and shear wave velocity. Laboratory testing was conducted to rmine the physical properties of the soil and rock. A detailed listing of the site investigation gram is included at the beginning of Section 2.5. Evaluations of the subsurface conditions, soil rock properties, and results of stability analyses are presented herein. Analyses incorporate vibratory ground motion associated with the safe shutdown earthquake (SSE) where ropriate.

4.1 GEOLOGIC FEATURES geologic setting and site structural geology of the Millstone 3 site is discussed in tions 2.5.1.2 and 2.5.3, and the local geology is shown on the site bedrock geology map ure 2.5.1-13).

rock surface, mapped prior to excavation, is fresh with few zones of weathering. The thering is not excessive and occurs generally in highly jointed areas or along a fault zone. The of rock has been glacially smoothed and eroded by outwash waters. Many of the joints have n filled with glacial till. In the southern portion of the main excavation in the discharge tunnel

, six low angle joints (394, 398, 424, 425, 577, 645) exhibiting slight displacement due to the ging action of the glacial ice have been mapped. The location of these joints are shown on ures 2.5.4-1 through 2.5.4-5.

evidence of large stress concentrations developed during the rock excavation for Millstone 3.

re was no observable stress relief in the form of popping rock, rock bursts, or notable rock vement. No significant problems were noted from rock stresses in the Millstone Point quarry le and Gregory 1911; Dale 1923). However, Niles (1975-76) indicated that the thin webs of k between closely spaced holes had popped while line drilling, and that the drills had become nd.

close spacing of the drill holes and the binding of the drills were probably caused by the ase of the residual stress in the rock mass.

Geologic Mapping During Construction al excavation grades and most of the top of rock were geologically mapped during excavation the safety related structures. A summary report of the mapping of the bedrock surface and e subsequent reports concerning faults subsequently uncovered at the site have been mitted to the Nuclear Regulatory Commission (NRC) (NNECo. 1975, 1976, 1977, 1982).

ults of site geologic mapping are discussed in Sections 2.5.1.2 and 2.5.3. Field sketches were pared for the floors of structures at the scale of 1:120, and the walls and the major fault zones e prepared at a scale of 1:60. These scales have been reduced in this document for publication

bols, and slickensides correspond to descriptions listed in Tables 2.5.4-1, 2.5.4-2, and 2.5.4-espectively.

geologic maps of the containment and engineered safety features (ESF) building excavation ls are shown on Figures 2.5.4-10 through 2.5.4-14 and 2.5.4-18. Tables 2.5.4-4, 2.5.4-5, and 4-6 list the joint, foliation, and slickenside information for the containment and ESF dings, respectively.

excavation walls of the auxiliary building pipe tunnel pit and the north wall of the excavation shown on Figures 2.5.4-15 through 2.5.4-17. The service water pipeline walls and discharge nel excavation floor and walls are shown on Figures 2.5.4-1 through 2.5.4-5 and 2.5.4-19 ugh 2.5.4-27. Lists of joint, foliation, and slickenside information are given in Tables 2.5.4-7, 4-8, and 2.5.4-9, respectively.

igneous intrusions and biotite concentrations that cross the site are numbered for continuity for distinguishing the different intrusions that cross discontinuities caused by faulting and ation differences in the excavation.

faults uncovered at the site are shown on Figures 2.5.4-6 and 2.5.4-19 and are listed in le 2.5.3-1. The nature and age of the faults are discussed in detail in Section 2.5.3.2.

4.2 PROPERTIES OF SUBSURFACE MATERIALS eries of investigations was conducted in the field and in the laboratory to determine the perties of the subsurface materials existing at the site and the compacted backfill materials cessed from offsite sources. Materials underlying the site include beach sand, unclassified am deposits, ablation till, basal till, and hard, crystalline bedrock of the Monson Gneiss mation. The field investigations included soil and rock borings, geologic mapping, piezometer allation and monitoring, water pressure testing of the bedrock, seismic refraction and ection surveys, and cross-hole and up-hole seismic surveys. The field testing is described in il in Section 2.5.4.3. The laboratory investigations included index property and gradation rminations of onsite soils, moisture-density relations, and direct shear testing of compacted kfill, shear modulus, and damping determination and cyclic and static triaxial testing of beach ds, unconfined compression testing of bedrock core samples, and joint and foliation friction rmination for bedrock surfaces.

oratory testing of site soils and backfill source materials was conducted in the Stone &

bster Engineering Corporation (SWEC) Soils Laboratory. Field testing for backfill control ng placement was conducted in the SWEC Field Quality Control Laboratory, located onsite.

mpacted backfill test results are discussed in Section 2.5.4.5.2. Intact rock core specimens e tested for unconfined compressive strength and unit weight by Prof. K. Tsutsumi of Tufts versity. Results of these tests are presented in Table 2.5.4-10. Direct shear tests along jointed foliated rock surfaces on specimens selected from NX core samples were performed in the EC Soils Laboratory. A description of these tests is presented in Section 2.5.5.2 and data are

he pumphouse. The results of this study are presented in the GEI report, Appendix 2.5F.

solidated undrained (CIU) tests were also performed on samples of the beach sands in the EC Soils Laboratory. The results of these tests are tabulated in Table 2.5.4-12 and endix 2.5G.

rlying the bedrock at the Millstone site are five groups of soils. They are from youngest to est: artificial fill, beach deposits, unclassified stream deposits, ablation till, and basal till. Each hese is discussed in the following sections.

4.2.1 Artificial Fill ficial fill material is comprised of a mixture of till, waste rock materials excavated from the lstone 1 and 2 sites, and some quarry waste. Consequently, it is a heterogeneous mixture.

se fill materials were not placed in controlled thin-lift construction and are not a satisfactory ndation material for structures of any kind. All artificial fill has been excavated when ountered and no structures, pipelines, or electrical ducts are founded on this material.

4.2.2 Beach Deposits beach deposits are the youngest naturally occurring material in the site area. These are ent for the most part only in the cove east of Bay Point, in the area of the circulating and ice water pumphouse. For the most part they consist of uniform silty sand. The beach deposits generally denser than the alluvium deposits due to wave action from Long Island Sound.

ic and cyclic triaxial and resonant column tests were performed on the beach deposits to estigate liquefaction potential and obtain shear strength parameters for slope stability analyses he shoreline area. The results of these tests are tabulated in Table 3 of Appendix 2.5F. These lyses are discussed in Section 2.5.4.7, 2.5.4.8, and 2.5.5.2.

mposite plots of relative density and corrected blow count (N) vs effective overburden stress ed on Gibbs-Holtz relations are presented on Figures 2.5.4-28 and 2.5.4-29, respectively.

se plots show that the beach sand is a medium dense deposit with an average relative density pproximately 70 percent, with most points denser than 60 percent. Some points do plot lower, these low density values are generally indicative of the looser, unsaturated sand near the und surface.

major plant structure, pipeline, or duct is founded on the beach deposits. This material was avated and replaced with compacted select backfill under portions of the service water line, remains in place along the shoreline, adjacent to the circulating and service water pumphouse.

4.2.3 Unclassified Stream Deposits lassified glacial stream deposits west and southwest of Millstone 3 consist of sands with some and gravels. Thicknesses of the deposits vary, and exposed cuts reveal the sediment to be

nt of the unclassified stream deposits is shown on the site surficial geology map ure 2.5.1-3).

major plant structure, pipeline, or duct is founded on unclassified stream deposits. Prior to allation of any foundations, all underlying loose deposits were removed to sound basal till or rock and replaced with compacted backfill, as discussed in Section 2.5.4.5.2.

4.2.4 Ablation Till ation till overlies the dense basal till in the area where the major plant structures are located.

s material consists of glacially transported debris which was deposited as the supporting and/

nclosing ice melted away from it. The ablation till has not been compacted by ice and is, efore, less dense than the basal tills, but is still a strong, stable soil. Both the basal till and the rlying ablation till are relatively impervious. The ablation till is more pervious than the basal because it is irregularly stratified with lenses of sand and gravel and mixtures of cobbles, vels, sands, and silts.

dation analyses and moisture content determinations were conducted on split spoon samples he ablation till. The gradation curves indicate that the ablation till is a silty sand, with typically o 40 percent finer than the No. 200 sieve. The gradation curves are presented on Figure 2.5.4-plotted with the Lee & Fitton (1969) and Kishida (1969) gradation envelopes of soils most ly to liquefy during the earthquake. The ablation tills at the Millstone site are significantly e widely graded and coarser than the soils typified by these envelopes. The natural moisture tent of the ablation till varies from 5 to 15 percent. Moisture content determinations from split on samples of various overburden materials at the site is presented in Table 2.5.4-13.

roximately 500 feet of the circulating water discharge tunnel in the vicinity of Millstone stack ounded on crushed stone and concrete fill overlying ablation till. At all other structures, the tion till was removed to sound basal till or bedrock and replaced with compacted backfill, if uired, as discussed in Section 2.5.4.5.2.

4.2.5 Basal Till al till overlies bedrock at the site area, varying in thickness from less than 5 feet in the phouse area on Niantic Bay to over 40 feet under the turbine building. The basal till is a very se material of low permeability consisting of a widely graded mixture of cobble and boulder-rock fragments, gravel-size material, sand, and some silt binder. The basal till was overridden compacted by ice during the glacial period, accounting for its characteristic very dense state high strength.

dation analyses and moisture content determinations were conducted on split spoon samples he basal till. Although only the minus 1 inch portion of the basal till was tested, the gradation ves presented on Figure 2.5.4-30 show that the basal till consists of a widely graded silty sand

) with 10 to 25 percent finer than the No. 200 sieve and a coefficient of uniformity (D60/D10)

le 2.5.4-14. A detailed discussion of the liquefaction potential of the basal till is presented in tion 2.5.4.8.2 and a discussion of the static stability of structures founded on basal till is uded in Section 2.5.4.10.1.

stic constants have been determined by seismic cross-hole and up-hole surveys. Details of this y are presented in Section 2.5.4.4.3 and Appendix 2.5HThe average Young's modulus (E) rmined for the basal till was 4 x 105 psi and the average shear modulus (G) determined was x 105 psi. A Poisson's ratio of 0.44 has been calculated based on these values of E and G.

4.2.6 Monson Gneiss country rock at the site is the Monson Gneiss. At the site area, the Monson Gneiss is thinly red with light feldspathic and dark biotitic and hornblendic layers. The foliation is well ned and exhibits a consistent northwest trend. Based on data accumulated during geologic ping at the site during excavation, the average foliation attitude of the Monson Gneiss is W, 48NE, (N54W, 48NE grid north). A stereonet projection of the foliation is presented on ure 2.5.1-15.

ting at the site is characterized by an average attitude of N03W, 63NE (N10E, 63SE). (All kes are referenced to true north, which is 13.5 degrees east of grid north. Bearings in ntheses represent grid north.) Minor joint sets observed at the site are N02W, 78NW, (N11E, W) and N69E, 74SE (N82E, 74SE). A low angle joint set oriented at N48W (N35W) dips 7 rees northeast. A lower hemisphere stereonet plot of poles to the joint planes is shown on ure 2.5.1-16 and a complete list of all measured joints and foliations is presented in les 2.5.4-1, 2.5.4-4, 2.5.4-7 and 2.5.4-2, 2.5.4-5, and 2.5.4-8, respectively. In general, the ts are linear and tight and exhibit smooth surfaces. A large number of the joints are coated h chlorite and many exhibit iron oxide staining.

ect shear tests were performed on several joint and foliation surfaces. These tests indicate that average residual shear stress for joint surfaces is 34.5 degrees, and the average residual shear ss for the foliation is equal to 32 degrees. Details of the testing program are presented in endix 2.5I.

onfined compression and density tests were performed on nine core samples of Monson iss and two samples of Westerly Granite. The unconfined compressive strength of the nson Gneiss varied from approximately 4,000 to 14,000 psi, with an average value of 10,000 The unit weight of Monson Gneiss ranged from 161 to 168 pcf, with an average value of 165 The Westerly Granite was slightly stronger and less dense. The average unconfined pressive strength of the two samples was approximately 13,000 psi and the unit weight raged 157 pcf. The results of the rock compression tests are tabulated in Table 2.5.4-10.

eophysical survey was performed, consisting of measuring compressional P wave and sverse S wave velocities using both down-hole and cross-hole techniques. Average values

e 4 x 106 psi, 1.5 x 106 psi, and 0.33, respectively. The geophysical investigations are ussed in detail in Section 2.5.4.4.3 and Appendix 2.5H.

4.3 EXPLORATION tal of 95 test borings, both vertical and inclined, were drilled in the rock and soil at the site.

boring locations are presented on Figures 2.5.4-31 and 2.5.4-32. Table 2.5.4-15 is a listing ll boring coordinates, ground elevations, top of rock elevations, and groundwater elevations at time of drilling. Complete boring logs are presented in Appendix 2.5J. The logs describe the and rock types, the location, elevation, and type of samples recovered, the standard etration test value (N), and the core recovery and rock quality designation (RQD) of the rock. Geologic profiles are presented on Figures 2.5.4-33 through 2.5.4-35 and the basal till ace contour map is presented as Figure 2.5.4-36.

locations of boreholes in which water levels were taken are shown on Figure 2.5.4-37.

undwater elevations were monitored in borings 301 to 310 prior to construction, and the undwater fluctuations over a 2-year period for borings 303, 310, 311, 312, and 317 are shown phically on Figure 2.5.4-38. These wells were disturbed during construction; therefore, there o record reported in these wells subsequent to December 1973. Site groundwater conditions, ed on regional data, site piezometers, and observations during construction, are discussed in il in Sections 2.4.13 and 2.5.4.6.

er pressure tests were performed in three borings to assess the degree of weathering and meability of the bedrock. The results of the tests are presented in Table 2.5.4-16.

eismic refraction survey to determine compression wave velocities and depths to various strata performed by Weston Geophysical Engineers, Incorporated (WGEI) and is discussed in tion 2.5.4.4.1. The location of the seismic refraction lines and the seismic profiles are ented in Appendix 2.5K.

mic cross-hole and up-hole techniques were employed at the site in order to determine the es of dynamic moduli and Poisson's ratio for the ablation till, basal till, and bedrock. The lts are tabulated and discussed in Section 2.5.4.4.3. The WGEI report on these tests is ented as Appendix 2.5H.

4.4 GEOPHYSICAL SURVEYS physical surveys were conducted to determine the nature and extent of subsurface materials at site. The studies included a seismic refraction survey of the site in the vicinity of the major ctures, an offshore seismic and bathymetric survey employing refraction and reflection niques, and seismic cross-hole and down-hole surveys to determine compressional and shear e velocities of subsurface materials.

eismic refraction survey was performed by WGEI to investigate subsurface conditions at the

. The purpose of the study was to determine compression wave velocities and depths of surface materials, and to prepare a preliminary bedrock contour map of the site area.

d procedures employed during the refraction survey are detailed in Appendix 2.5K.

refraction survey identified three major strata at the site according to seismic velocity. The r surface overburden material, identified as ablation till and discussed in detail in tion 2.5.4.2.4, typically has a seismic velocity ranging from 1,500 to 2,000 fps, indicative of a ium dense to dense, unconsolidated material. The transition between saturated ablation till moderately dense basal till corresponds to a zone with a seismic velocity between 5,000 and 0 fps. The very dense basal till, discussed in detail in Section 2.5.4.2.5, has a seismic velocity pproximately 6,700 fps. The thickness and extent of each of the overburden strata are shown he subsurface profiles in Appendix 2.5K.

harp increase in the seismic velocity was observed at the bedrock surface, indicating the ence of any extensive zones of weathered rock. This was verified during excavation for ctures. Typical seismic velocity values for the bedrock were approximately 12,000 fps, cative of a hard, massive, unweathered rock type. The soundness of the rock has been verified m the logging of rock cores from boreholes and from geologic mapping. The rock contour map ined from the seismic survey and shown on Sheet 3 of 8 in Appendix 2.5K agrees with the tour map of the bedrock surface shown on Figure 2.5.4-39, which is based on actual survey of the rock surface measured during construction.

4.4.2 Offshore Seismic and Bathymetric Survey eismic and bathymetric survey was conducted by WGEI to contour the Long Island Sound om and the bedrock surface offshore from Millstone Point, in the vicinity of the intake and harge structures, as shown on Figure 1 of Appendix 2.5L. Detailed profiling of the bedrock ace was obtained in some areas by means of continuous reflection techniques. Velocity values the different materials were determined from a seismic refraction survey. These values were d in computing depths to the reflecting horizons and for identifying the type of overburden erial and the quality of the bedrock.

bedrock and bottom contour maps for the four areas surveyed are presented in endix 2.5L.

4.4.3 Seismic Velocity Measurements mic velocity measurements using an explosive source were conducted at the site to rmine compressional P wave velocities and transverse, or shear, S wave velocities of the erlying materials. Both down-hole and cross-hole techniques were utilized. Elastic parameters basal till and bedrock obtained from these tests were used as the design basis for foundations hese materials. The field procedure is described in detail in Appendix 2.5H.

l -50 feet. Down-hole velocity measurements were made from el +5 feet to el -99 feet. There good agreement in the values between the two techniques.

ocity measurements of the overburden materials further distinguish between the two tills at the

. Shear wave velocity for the ablation till is approximately one-third lower than for the denser al till.

following seismic velocity profile is representative of materials in the vicinity of the turbine ding:

Seismic P Wave Elevation (ft) Material Technique (fps) S Wave (fps)

+15 to +4 Ablation Till Cross-hole 5,600 1,400

+ 4 to -24 Basal Till Cross-hole 6,800 2,200

-24 to -44 Bedrock Cross-hole 12,800 6,500 following seismic velocity profile is representative of materials in the vicinity of the reactor tainment structure:

Seismic Elevation (ft) Material Technique P Wave (fps) S Wave (fps)

+10 to -50 Bedrock Cross-hole 12,800 6,500

+ 5 to -99 Bedrock Down-hole 13,500 6,500 mic velocity measurements were made using an impact source of shear wave energy to rmine P and S wave velocities of materials underlying the discharge tunnel in the area of Millstone stack. Bedrock is overlain by basal till, ablation till, alluvium, and fill. The rburden in this area is up to 60 feet in thickness. In these tests, geophones were lowered into ch receiving holes to pick up arrival times generated from impact blows on a split-spoon pler positioned at the same elevation. The following seismic velocity profile is representative aterials in the vicinity of the discharge tunnel near the ventilation stack:

Elevation (ft) Material P Wave (fps) S Wave (fps)

+14 to + 2 Fill 1,363-3,060 814-1,238

+ 2 to -13 Alluvium 4,820-5,818 383-684

-13 to -18 Ablation Till 6,053-6,597 398-654

-18 to -30 Basal Till 7,539-7,603 1,246-2,387

rces.

values below are for low strain values from field generated tests and may not necessarily be d as design input. Final values used in design are calculated for individual structures.

Young's Modulus, E Shear Modulus, G Material (psi) (psi) Poisson's Ratio Rock 4 x 106 1.5 x 106 0.33 Basal Till 4 x 105 1.4 x 105 0.44 Ablation Till 2.7 x 104 9.0 x 103 0.49 4.5 EXCAVATIONS AND BACKFILL extent of excavations and backfill for major Seismic Category I structures is shown on ure 2.5.4-40. Final grading, which includes dredging and backfilling in the vicinity of the ulating and service water pumphouse, is shown on Figure 2.5.4-41. Profiles delineating the nt of the excavation and backfill are shown on Figures 2.5.4-33 through 2.5.4-35. Geologic ping of the excavated surfaces is described in Section 2.5.4.1.

4.5.1 Excavation founding materials for major plant structures are listed in Table 2.5.4-14. Most of the major ty related structures are founded on bedrock, with the exception of the control building, rgency diesel generator building, and the hydrogen recombiner building. The control building ounded on basal till. Isolated zones of softened till were excavated and replaced with fill crete or compacted structural backfill. The emergency generator enclosure building wall ings are founded on basal till. The diesel generator pads are supported on approximately 8 feet tructural backfill basal till as shown on Figure 2.5.4-55 (Geologic Profile J-J'). The hydrogen mbiner is founded on concrete fill overlying bedrock.

st of the circulating water discharge tunnel is founded on bedrock. Near the ventilation stack, a distance of approximately 500 feet, the discharge tunnel is founded on crushed stone and crete fill overlying basal till. Section 2.5.4.8.4 and Figure 2.5.4-51 (Geologic Profile H-H")

cribe the founding conditions of the discharge tunnel in this area.

service water intake lines are founded on bedrock in the main plant area; however, between main plant area and the pumphouse they are founded on soil. When soil was encountered as a nding material, all unsuitable overburden was removed to sound basal till. Where the invert ation was higher than the excavated grade, compacted structural backfill was placed in thin to the subgrade elevation of the pipe encasement. All compacted structural backfill was ed in accordance with procedures described in Section 2.5.4.5.2. Figure 2.5.4-52 (Geologic

locations of field density tests of structural backfill placed beneath the service water intake s near the pumphouse, where the deposit of beach and outwash sand was removed above the al till, are presented in Figure 2.5.4-53. Table 2.5.4-19 summarizes the results of the density s in this area.

k in the containment area was blasted and excavated in segmented areas, each approximately eet deep. Rock bolts, discussed in Section 2.5.4.12, were installed in the southwest sector of excavation to prevent potential sliding failures along the foliation. In addition, intercept drains e installed into the southwest excavation face to reduce the hydrostatic pressure on the ation and joint planes. No rock slides were noted during the time the excavation was in ice. However, some areas were overbroken due to blasting and to subsequent scaling rations to remove loosened rock wedges. The overbreak areas were localized and generally ted in size to approximately 2 cubic yards and less. The surfaces of the wedges generally formed to the predominant joint sets mapped at the site and discussed in Section 2.5.4.1. The re and extent of overbreak experienced during site excavation is considered normal for rock of this type and does not indicate instability in the rock mass.

ious techniques were utilized when blasting near the perimeter of structures to limit overbreak minimize damage to adjacent rock. The methods used include line drilling, cushion blasting, plitting, and smooth wall blasting. The purpose of each of these techniques was to develop a ar plane along the perimeter of the excavation so that the excavated rock breaks cleanly from face. In line drilling, the perimeter holes were closely spaced and left unloaded during the

t. Cushion blasting was used to blast a narrow berm left from a previous blast. A single row of ely spaced holes was drilled along the berm, lightly loaded, and fired simultaneously.

splitting consisted of the firing of a single row of lightly loaded, closely spaced holes, prior to primary blast. The purpose was to produce a crack along the line of presplit holes which the sequent primary blast could break. Smooth wall blasting is similar to cushion blasting except the lightly loaded perimeter holes were the last delay in the blast.

trolled blasting techniques were used to limit the vibrations felt at Millstone 1 and 2 and to lude any structural damage to concrete or bedrock near the blast. Peak particle velocity was sured for each blast, using Sprengnether 3 - component seismographs. No damage to any cture or component in the two operating units or the Millstone 3 construction site was erved as a result of the blasting.

inflow of water into the excavation was controlled by means of pumping from local sumps.

s was possible due to the low permeability of the soils and the tightness of the joints in the rock. Concrete working mats were poured on all foundation surfaces upon excavating each in order to minimize the impact of construction activities on the undisturbed founding aces.

e softening of the basal till in sections of the excavation was observed. The softening is butable to the exposure of the till to the affects of weathering and construction traffic. When

avation, softened till approximately 1 foot in thickness was hand-excavated to firm till and aced with structural backfill. The extent of the softening was verified by excavating two test ches into the till to a depth of 4 feet. No additional softened till was encountered below the ened surface layer. The groundwater level was maintained below the subgrade by pumping m sumps outside the structure, and no seepage infiltrated the excavation after removal of the ened till and placement of the structural backfill.

4.5.2 Backfill egory I structures founded totally or partially on structural backfill include the control building emergency generator enclosure building. In addition, sections of the service water line and e of the buried electrical ducts are founded on Category I structural backfill.

erial used for Category I structural backfill is predominantly obtained from glacial outwash osits located at the Romanella Pit in North Stonington, Connecticut. Test data on borrow erial from the Romanella Pit have been previously reported in July and November 1974 and included in Appendix 2.5M. A small percentage is obtained from other borrow sources having ilar geologic characteristics. A description of the borrow material from three alternate sources ted in the towns of North Stonington, Preston, and Canterbury is included in a report mitted in June 1976 and is included herein as Appendix 2.5M.

structural backfill is processed at the borrow pit by means of passing the soil through a screen, uring that the maximum particle size and gradation meet the backfill specification uirements. For Category I structural fill, the gradation limits are:

U.S. Standard Cumulative Sieve Size Percent Passing 3 inches 100 3/4 inch 75 to 100 3/8 inch 65 to 90 No. 10 40 to 60 No. 40 15 to 35 No. 100 0 to 20 No. 200 0 to 15 fficient of Uniformity, Cu = D60/D10 10.

structural backfill was compacted to 95 percent of the maximum dry density determined from Modified Proctor Test, ASTM D1557, Method D. Moisture content was maintained within

ontinuing program of testing, inspection, and documentation was in effect during construction nsure satisfactory placement of backfill. Category I structural backfill was tested every 500 ic yards for conformance to the specified gradation limits prior to being allowed into the struction area. In addition, the maximum density was determined by ASTM D1557, Method for every 500 cubic yards of fill placed. Field density tests, using ASTM D1556, were ormed for each lift of fill, but not less than one test for every 500 cubic yards of fill placed.

ations of field density tests under the emergency generator enclosure and control building are wn in Figure 2.5.4-54, and the test results are summarized in Table 2.5.4-20. Cross-sections wing generalized subsurface profiles beneath these two structures are presented in ures 2.5.4-55 (Section J-J') and 2.5.4-56 (Section K-K').

ar strength of compacted backfill materials was determined from drained direct shear tests on ples compacted to 95 percent of maximum dry (ATMS D1557) density. Samples tested in the ct shear box contained only the minus No. 4 portion of the sample. For consistency, the imum density was also determined on the minus No. 4 portion of the sample. However, the imum density of the minus 3/4-inch fraction was tested in the field, and it can be assumed that maximum density of the minus No. 4 fraction would be less than the maximum density inable at the site on the whole sample. Consequently, testing the minus No. 4 fraction results alues of shear strength more conservative than would be expected for the whole soil sample. A parison of maximum densities for the minus No. 4 and minus 3/4-inch fractions for esentative samples from the major borrow areas used for Category I structural backfill is ented below:

@ 95%

d max d max d max @ 90%

(-3/4") (-#4) RX (-#4) d max (-#4)

Backfill Source (pcf) (pcf) (deg) (deg)

Romanella Pit (Sample 136.4 129.5 41.5 --

R)

Preston Pit 138.8 131.0 35.0 34.6 No. Stonington Pit 148.0 136.1 37.9 34.0 Canterbury Pit 140.0 131.6 39.4 34.0 Hathaway Pit (Waterford) 129.7 121.1 39.1 --

Ledyard Pit (Soneco) 132.6 122.9 41.4 --

strains:

2 2630 2.17 - e 1/2 (2.5.4-1)

G max = ---------------------------------------- o 1+e re:

Gmax = maximum shear modulus in psi e = void ratio o = effective octahedral stress in psi d ratio was calculated assuming full saturation and a water content equal to 12 percent, which esents the water content at full saturation for a density of 95 percent of maximum, based on moisture-density curve for Sample R in Appendix 2.5M. The octahedral stress was assumed e equal to two-thirds of the effective overburden stress for a particular depth. The maximum ar modulus at a depth of 10 feet, which corresponds to the midpoint of the backfill layer eath the emergency generator enclosure building, is 13,400 psi. A profile of Gmax vs effective fining pressure is plotted on Figure 2.5.4-42.

esonant column test was performed on a sample of the structural backfill compacted to 95 ent of a maximum dry density. The values of Gmax plotted on Figure 2.5.4-42 obtained from test are in agreement with the Hardin and Black (1968) equation. The low strain damping o was calculated to be 1.4 percent.

ng's modulus for static strain levels was obtained through an iterative process where a value vertical strain was used to obtain a reduction factor for the G value. The value of E was ulated using the equation:

E = 2G(1+u) (2.5.4-2) re:

u = Poisson's ratio strain level assumed was checked with the expected strain level caused by the structural ing, using the equation:

(2.5.4-3)

= ---------z E

e = Vertical strain z = Increase in vertical stress from structure load E = Calculated value of Young's Modulus the emergency diesel generator enclosure building, the calculated vertical strain was roximately 10-3, and Young's modulus at a depth of 10 feet was approximately 10,000 psi. The ile of E static vs effective confining pressure is also plotted on Figure 2.5.4-42.

kfill placed behind concrete walls is described in Section 2.5.4.10.3.

4.5.3 Extent of Dredging acilitate the flow of water into the service and circulating water pumphouse, an intake channel been dredged to the limits shown on Figure 2.5.4-41. Side and longitudinal slopes of the ke channel are designed at 10 and 5 percent, respectively. The beach slope varies from 20 to ercent and is protected with heavy armor, as discussed in Section 2.5.5.1.

ings and laboratory testing in the beach area adjacent to the circulating and service water phouse indicate that the beach sands are generally moderately dense, with occasional thin es of less dense material. Liquefaction analyses of these sands, discussed in tion 2.5.4.8.3.2, indicate that a general liquefaction of the sand adjacent to the pumphouse is hly unlikely. If the looser zones do liquefy, the extent of the failure would be strictly local and ld not cause a massive soil movement into the dredged channel.

4.6 GROUNDWATER CONDITIONS undwater observations have been documented in previous reports (Ebasco 1966; Bechtel poration 1969). Water level readings in borehole piezometers were taken for the Millstone 3 study between 1971 and 1973. In addition, pressure testing of rock in three boreholes and ng installation of rock anchors in the turbine and service buildings was conducted to rmine the permeability of the rock mass. Also, temporary drains were installed in sections of containment excavation face and the inflow of water into all excavations was observed ughout construction. These observations form the design bases for groundwater at the site, as ussed below.

4.6.1 Design Basis for Groundwater undwater observations at the site prior to construction were made in piezometers installed in eral borings. Listings of the water elevations and dates of reading are presented in Table 2.5.4-Three borings, 303, 310, and 311, were continually monitored over a 2-year period. A plot of ation vs date for water levels in these boreholes is shown on Figure 2.5.4-38. As a result of e observations, a stabilized groundwater level contour map, based on the water levels

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 indicates that bedrock acts as a groundwater divide, isolating the soils of the of Millstone Point from soils further inland. Thus, groundwater recharge would primarily be to absorption of local precipitation, with probable migration of the waters to the immediately cent Long Island Sound. Little groundwater is present in the crystalline bedrock, and virtually f the groundwater movement is restricted to the soil overburden.

asurements taken during previous investigations (Bechtel Corporation 1969) showed average ux rates into test pits of about 8 gallons per hour, and it was concluded that both the ablation basal tills were relatively impervious. The ablation till soils are more pervious than the basal and occasionally exhibit partial stratification, including sporadic sand lenses. Thus, the upper ions of the soil transmits water more readily than the underlying dense basal tills.

structures are designed for the groundwater levels shown in Table 2.5.4-14 which are based groundwater contours plotted on Figure 2.5.4-37. No safety-related permanent dewatering em is required to lower groundwater levels. These groundwater contours represent average undwater elevations of the site prior to the start of construction. A comparison of groundwater tours with the top of basal till contours on Figure 2.5.4-36 verifies that the primary medium groundwater flow is the permeable surficial soil overlying the basal till. Recharge of the undwater occurs mainly from precipitation infiltrating through the surficial soils, and flowing ard Long Island Sound and the outwash deposits above the till.

struction of the plant results in large changes to the site geohydraulic conditions. Site grade been lowered to a uniform elevation of +24 feet from the original site grade which varied m elevation 26 feet to 30 feet. The major plant structures are founded at approximately ation 0 feet on blasted rock excavations and backfilled from subgrade level to the ground ace with fill materials of relatively high permeability. The backfilled zones under and around e structures and the circulating water intake pipelines provide a continuous hydraulic conduit groundwater flow from the plant area to Long Island Sound. Therefore, the average water ls prior to construction are not necessarily representative of post-construction groundwater ditions. Design groundwater levels used in plant design are shown in Table 2.5.4-14.

eepage diversion system, consisting of a series of underdrains and porous concrete, has been alled under and around several structures to minimize the amount of seepage into the ement of structures founded below the groundwater table. The quantity of seepage expected to iverted through the system is small, due to the low permeability of the basal till and rock at site. This system is not considered safety related because dewatering is not necessary to ensure stability of any structure. However, enough leakage occurs to require pumping for equipment ection. The containment and all other Category I structures are protected from groundwater ow by a waterproof membrane below the groundwater level. Water which penetrates or umvents the membrane is diverted to the Engineered Safety Features Building porous

ty-related pump (see Section 9.3.3 for details of this system.)

er levels measured in borings taken at the site in early 1972 indicate a groundwater ometric surface with a 3-percent gradient generally sloping from northeast to southwest, as wn on Figure 2.5.4-37.

discussed in Section 2.4.2.2, Flood Design Considerations, the controlling event for flooding he Millstone 3 site is a storm surge resulting from the occurrence of the probable maximum icane (PMH). The maximum stillwater level resulting from hurricane surge was calculated to elevation 19.7 feet msl. As shown on Figure 2.4-9, the water level drops significantly with e, so that after 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> the flood level is at elevation 17 feet and after 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> the surge level sides to elevation 10 feet. A continuous hydraulic connection would occur across the site from main structure area to the shorefront through the backfill placed around structures and the kfill placed in the circulating water pipeline trench. It can be expected that the maximum undwater level due to flooding would not exceed elevation 19.7 feet and would probably be because of head losses in the soil. According to Figure 2.4-9, the water level drops to 17 feet r 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.

design groundwater levels for major safety-related structures shown on Table 2.5.4-14 are all al to or greater than elevation 19 feet with the exception of the hydrogen recombiner building, ch has a design groundwater level of 18 feet. However, founding grade is at elevation 20 feet this structure, which is founded on concrete fill placed directly on bedrock. Design criteria for d conditions are discussed in Section 3.4.

4.6.2 Groundwater Conditions During Construction ing construction, the inflow of water into the excavations was controlled by pumping from ps located outside of the building lines adjacent to structures. Most flow through the rburden was transported through the sand lenses. All water-softened material was removed replaced with a fill concrete working mat as described in Section 2.5.4.5.1. The rate of inflow sufficiently low to allow enough time to pour the concrete working mat without further ening of the till.

inage pipes were installed in the southwest face of the containment excavation in order to eve the hydrostatic pressure on the bedrock joint and foliation surfaces. Very little water was erved flowing through these pipes, indicating that the quantity of flow through the bedrock is ll and that the permeability of the rock is low.

er pressure tests were performed in three boreholes prior to construction. These tests indicated the rock within the site area is generally massive with slight to moderate interconnected ting. A summary of the water pressure test data from the boreholes is included in Table 2.5.4-Additional pressure tests were performed prior to installation of rock anchors in the turbine service buildings. These tests further verified the low permeability of the rock mass.

4.7 RESPONSE OF SOIL AND ROCK TO DYNAMIC LOADING Seismic Category I structures and associated piping are founded either on bedrock, basal till, tructural backfill. Portions of the circulating water discharge tunnel are founded on ablation in the vicinity of the Millstone stack north of Millstone Unit 1. A listing of the founding strata all Category I structures is included in Table 2.5.4-14.

d crystalline bedrock forms the basement complex of the area. The overlying dense basal till sists of a hard, compact soil which has been heavily preloaded by continental ice. Static and amic properties of the basal till and bedrock are discussed in Sections 2.5.4.2.5 and 2.5.4.2.6, ectively. Static and dynamic properties for the compacted structural backfill are discussed in tion 2.5.4.5.2.

bedrock, basal till, ablation till, and structural backfill are stable materials under vibratory ion caused by the SSE. The basal till, ablation till, and structural backfill are not susceptible to efaction, as discussed in Section 2.5.4.8.

soil-structure interaction analyses for Seismic Category I structures founded on soil were ormed using the computer program PLAXLY-3. The nonlinear behavior of the subgrade was ounted for by use of the computer program SHAKE (LaPlante and Christian 1974) which was d to determine the strain-corrected soil properties. The subsurface material properties used in SSI analysis are discussed in Section 2.5.4.7.1. The method of SSI analysis and the results are ussed in Section 3.7.2.4.

response of buried piping to seismic loadings is discussed in Section 3.7.3.12.

shorefront west of the circulating and service water pumphouse consists of a structural fill beach and outwash and slope varying from 5H:1V to 10H:1V, protected by graded layers of or stone. A plan showing the extent of the shoreline protection system is presented on ure 2.5.4-41. A typical section is shown on Figure 2.5.5-1. Static and dynamic properties of beach sands are discussed in Section 2.5.4.2.2 and documented in the reports in endix 2.5F and 2.5G. The liquefaction potential of the beach and outwash sand is discussed in tion 2.5.4.8. The stability of the shoreline slopes under static and dynamic loading is discussed ection 2.5.5.2.

service water intake pipes, between the circulating and service water pumphouse and the n plant area, are embedded in a rectangular concrete encasement. Soils encountered in the eline excavation include beach and outwash sands, unclassified stream deposits, and ablation These soils were removed under the pipeline to dense basal till and replaced with Category I ctural backfill. The fill was placed at a 1:1 slope from the till surface to the base of the asement and compacted to the requirements outlined in Section 2.5.4.5.2. The sides of the asement were backfilled with nonstructural fill similar to the material used to backfill behind

4.7.1 Subsurface Material Properties Used in SSI Analysis subsurface profiles used in the soil-structure interaction analyses for the control building and emergency generator enclosure (EGE) are idealized, horizontal profiles based on subsurface lorations conducted at the site and described in Section 2.5.4.3. Both of these structures are nded on dense basal till overlying bedrock. The computer program SHAKE was used to rmine strain corrected values of shear modulus obtained from low strain values previously rmined from field testing, laboratory testing, or empirical formulae based on laboratory test

. The program iterates to obtain values of modulus that are compatible with strain levels uced in a particular soil layer by a specific earthquake. The strain levels normally induced by hquakes of magnitudes similar to the Millstone SSE are several orders of magnitude higher the low strain levels achieved during laboratory or field testing, resulting in a reduction in ar modulus when these properties are corrected for strain and input into PLAXLY-3.

soil-structure model used in the EGE analyses is shown on Figure 2.5.4-72. This idealized ile was selected to conservatively model the subsurface conditions under the EGE and in the

-field. The geologic profiles presented in Figures 2.5.4-55, 2.5.4-56, and 2.5.4-71 indicate the rock surface slopes from approximately elevation 0 feet at the east end of the structure to ast elevation -10 feet at the west end. In the north-south direction, the sloping evacuation face ween the control building and the south end of the EGE was backfilled with structural fill over basal till. The extent of structural fill is shown on Section J-J (Figure 2.5.4-55) and ure 2.5.4-54. Because the depth and extent of the structural fill under the EGE is limited, it assumed that the model used in the SHAKE analysis is sufficiently conservative to account local variations in the subgrade and their effect on structural response.

soil properties input into the SHAKE calculation are listed in Table 2.5.4-21A for the free-d model and Table 2.5.4-22B for the structure-effects model. Three earthquake time histories, m the Taft, Helena and Parkfield earthquakes, were normalized to the site SSE peak eleration value of.17g and input at bedrock. Shear modulus and damping iterations were ormed within the SHAKE program in accordance with the curves marked Resonant Column t on Figures 2.5.4-73 and 2.5.4-74. These curves were developed from empirical formulae resonant column tests performed on samples of compacted structural fill from the Millstone

. These test results are presented on Figure 2.5.4-42. The tests show good correlation with ves present by Seed and Idriss in the SW-AJA report (1972).

strain corrected values of shear modulus and damping in the free-field are presented in le 2.5.4-21A. The mean value for each layer was calculated and used to represent the vidual soil layer properties used in the PLAXLY model shown on Figures 3.7B-11 and 3.7B-The Millstone site artificial earthquake was input at bedrock and the soil was modeled as a te element mesh. The use of SHAKE to perform shear modulus and damping iterations cludes the need to iterate in the PLAXLY model. A discussion of the soil-structure interaction lysis is presented in Section 3.7B.2.4.

. Shear wave velocities were used to define soil stiffness. The low strain and strain-corrected properties for the free field case are listed in Table 2.5.4-23.

4.8 LIQUEFACTION POTENTIAL foundation materials beneath some of the Seismic Category I structures consist of limited ths of dense to very dense basal tills and/or compacted select granular backfill. These erials are not susceptible to liquefaction under earthquake motions as described in the owing sections.

4.8.1 Structural Backfill ed on studies of soils where liquefaction has been observed (Seed 1968, Lee and Fitton 1969, hida 1969), it is concluded that the structural backfill described in Section 2.5.4.5.2 in areas w the groundwater table is not susceptible to liquefaction, as discussed below.

1. A liquefiable soil is generally a uniform sand with a uniformity coefficient of not more than 10 (Kishida 1969). The structural backfill has a uniformity coefficient ranging from 25 to 50 (Figure 2.5.4-44).

2. A soil having a relative density of more than 75 percent is not likely to liquefy (Kishida 1966, 1969; Koizumi 1966; Lee and Seed 1967; Seed and Lee 1966).

Accordingly, compaction criteria of the structural backfill given in Section 2.5.4.5.2 have been designed to yield a relative density higher than 75 percent.

3. According to the envelope of most liquefiable soils given by Lee and Fitton (1969), which also contains the envelope given by Kishida (1969), the average particle size, D, of the most liquefiable soils envelope is between 0.02 and 0.7 mm, whereas the corresponding particle size of the structural backfill used is larger than 1.0 mm (Figure 2.5.4-44).

concluded, therefore, that the structural backfill compacted as outlined in Section 2.5.4.5.2 is susceptible to liquefaction during the SSE.

4.8.2 Basal Tills ed on the regional geologic history, the basal tills are very dense deposits consisting of well ded materials ranging in size from boulders to clay (Section 2.5.1.2.3). Figure 2.5.4-30 shows dation curves for the basal till specimens. These specimens were recovered by split spoon pling with a 1 3/8-inch inside-diameter sampler. The gradation curves show that the till is well ded with a uniformity coefficient of about 80 and many particles larger than 3/8 inch. Larger icles present in the till (1 3/8+ inches) could not be recovered by the split spoon. The actual dation curves for the samples would therefore be shifted to the left of those on the figures, lting in a still wider graded soil than shown.

elope from sand deposits which liquefied in Japan. Kishida also notes that a criterion for uefiable soils is that the uniformity coefficient is generally less than 10. The gradation curves the basal till do not satisfy this criterion and are not enclosed within the envelopes developed ither Lee and Fitton or Kishida.

onclusion, the well graded grain size characteristics and the high relative density of the basal preclude the possibility of liquefaction in terms of criteria developed by Kishida (1969) and and Fitton (1969).

4.8.3 Beach and Glacial Outwash Sands circulating and service water pumphouse is located on the shorefront of Long Island Sound, roximately 200 feet west of the Millstone 2 intake structure. The pumphouse is founded on rock; however, the intake channel and adjacent slopes consist of beach and glacial outwash d to approximately el -40 feet. Based on the results of grain size analyses of samples obtained m the pumphouse area, the beach and glacial outwash sands consist mostly of medium to fine silty sand with a few layers of gravelly sand. High concentrations of mica are found ughout the sands in this area.

grain size ranges for beach and outwash sands in the pumphouse area are shown on ure 2.5.4-57. Envelopes of the most liquefiable soils are also shown on these figures.

beach and outwash sands are saturated below sea level. Grain size analyses indicate that a efaction analysis of the sands should be performed to determine whether these sands could efy and slide into the intake channel, causing a potential blockage of the service water inlet es. The analyses described in Sections 2.5.4.8.3.1 and 2.5.4.8.3.2 show that the safety factor inst liquefaction for the beach and glacial outwash sands is greater than 1.1 for the site SSE 7g. Therefore, these sands would not liquefy as a result of the SSE.

4.8.3.1 Dynamic Response Analysis of Beach and Glacial Outwash Sands dynamic response analysis of the shorefront sand deposits has been evaluated to assess the ntial amplification or deamplification of ground motions applied to the bedrock surface. This luation was made using the SHAKE (LaPlante and Christian 1974) computer program for lysis of the vertical transmission of horizontal shear stresses induced by the SSE through a red system. This program treats the strain dependence of the shear modulus and damping ratio n iterative manner.

onservative, idealized profile was selected due to the variability of the rock surface and sisted of 40 feet of sand (the maximum sand thickness in the area) overlying 5 feet of basal till bedrock. The sand layer was divided into four layers, each 10 feet thick, and the till was lyzed as a single layer. Groundwater level was established at 10 feet below the ground surface, corresponds to the mean high water level in Niantic Bay. The shear moduli and damping os of the sand were obtained from tests discussed in Section 2.5.4.2.2 and described in detail in

dulus of the basal till and bedrock was determined from geophysical surveys described in tion 2.5.4.4.1.

values of shear modulus (G) and damping (D) used in the SHAKE analysis for each layer are:

Layer Depth (ft) Soil Type Gmax (ksf) Dmax (%)

1 0-10 Sand 600 1.8 2 10-20 Sand 1,250 1.8 3 20-30 Sand 1,600 1.8 4 30-40 Sand 1,800 1.8 5 40-45 Till 2,500 1.8 reduction of Gmax with strain was performed through a series of iterations, based on the tionship 1/2 G = 1000K 2 m (2.5.4-4) re:

K2 = a constant that varies with shear strain, developed from resonant column tests and plotted on Figure 2.5.4-45, m = the mean principal effective stress in psf, and G = the shear modulus at a particular shear strain in psf.

time history of the following earthquakes, normalized to the site SSE value of 0.17g, were ut at the bedrock surface:

1. 1965 Olympia Earthquake (S86W component)

2. 1935 Helena Earthquake (west component)

3. 1971 San Fernando Earthquake (Pacoima Dam, N74W component) s analysis indicated that the average maximum acceleration would be 0.27g at ground surface the free-field case of the beach prior to construction of the shoreline slopes. The average shear ss induced by the earthquake, assumed to be 0.65 of the peak value, was calculated to vary m 107 psf at a depth of 5 feet to 410 psf at a depth of 42.5 feet for an effective strain level of than 0.1 percent. Shear stresses vs depth are plotted on Figure 2.5.4-46.

cedures for liquefaction analyses, developed by Seed et al. (Seed and Lee 1966, Seed and ss 1967, 1971), require the following quantitative evaluations:

1. The magnitude of shear stresses induced at varying depths in the underlying sand due to earthquakes.

2. The resistance of the sands to liquefaction, which may be expressed as the cyclic shear stress necessary to cause initial liquefaction in the number of cycles estimated to occur in an earthquake of the intensity selected (also known as the significant number of cycles to cause liquefaction).

resistance of a soil to liquefaction is expressed as a factor of safety, equal to the ratio of the ar strength available to resist liquefaction to the shear stresses induced by the earthquake.

SSE at the site is based on an Intensity VI-VII earthquake which corresponds to a magnitude pproximately 5.3 using relationships developed by Gutenberg and Richter (1942). Based on ure 2.5.4-58 from Seed, Idriss, et al. (1975), the irregular shear stress time history of the SSE be represented by five equivalent cycles of loading.

shear stresses induced by the SSE were calculated using the SHAKE program, assuming a imum bedrock acceleration of 0.17g. A discussion of the analysis and results for the sand is uded in Section 2.5.4.8.3.1.

cyclic shear stress necessary to cause initial liquefaction, or the shear strength available to st liquefaction, was determined from cyclic triaxial tests conducted on undisturbed samples m borings in the vicinity of the pumphouse. The testing program and results are described in il in Appendix 2.5F.

shear stress necessary to cause initial liquefaction in the field, res, is calculated from the owing equation:

1 - 3 res = v ------------------ C r (2.5.4-5) 2 c cyc

v= Vertical effective stress 1 - 3

- = Cyclic stress ratio 2

c cyc Cr = Reduction factor to be applied to laboratory triaxial test data to obtain the stress conditions causing liquefaction in the field.

the beach and glacial outwash sands at the site, the factor of safety was calculated at depths of 15, 25, 35, and 40 feet below the ground surface. The cyclic stress ratio for a particular depth vertical effective stress was determined from Figure 2.5.4-47, a plot of cyclic stress ratio vs fining pressure. This plot is based on test data from Figure 21 of Appendix 2.5F, assuming efaction occurs at a strain of 10 percent double amplitude.

factors of safety for liquefaction, based on Cr equal to 0.60, are shown in Table 2.5.4-18. The imum factor of safety calculated from laboratory tests is 1.25 at a depth of 40 feet. This factor afety is sufficiently large considering the conservative assumptions included in the analysis.

additional method of assessing liquefaction potential can be developed by comparing standard etration resistance data from the vicinity of the pumphouse structure with standard penetration stance data from sites which have been subjected to earthquakes. This method, described in il below, also indicates there is no danger of liquefaction in the beach sands at the site.

empirical approach relating standard penetration resistance data (N values) to liquefaction ntial was proposed by Seed, Arango, and Chan (1975), who presented cyclic strengths based empirical data from sites which did and did not experience liquefaction during earthquakes.

o included were data from large-scale shake table tests by DeAlba, Chan, and Seed (1975) ch were corrected to account for effects of stress history and multidirectional shaking. Based hese data, Figure 6-1 of Seed et al. (1975) (included herein as Figure 2.5.4-48) presents lower nds of the cyclic stress ratios causing liquefaction versus the standard penetration resistances ands for magnitudes 5 to 6 and 7 to 7 1/2 earthquakes, corrected to an effective overburden sure of 1 ton per square foot (N1) based on the Gibbs and Holtz (1957) correlation of relative sity of sands to blow count and effective stress. A plot of N1 values vs effective stress used in method is the SPT blow count for borings P1 through P8 and I2, I3, I8, I9, and I10 is included igures 2.5.4-28 and 2.5.4-29. The mean value of corrected blow count for these borings was ulated as 20.0, which corresponds to a cyclic stress ratio of 0.278 for a magnitude 5 to 6 hquake, using Figure 2.5.4-48. When compared with the earthquake induced shear stresses ined from the SHAKE analysis described in Section 2.5.4.7, the minimum factor of safety inst liquefaction calculated by this method was 1.68 at a depth of 15 feet.

ery conservative factor of safety against liquefaction was also calculated using a cyclic stress o based on the mean corrected blow count less one standard deviation. An N1 value of 13.1 used to obtain a cyclic stress ratio of 0.185 from Figure 2.5.4-48. The minimum factor of

eptable, considering the fact that the mean value of N1, less one standard deviation, is well w the mean value originally used by Seed et al. in determining the curves in Figure 2.5.4-48.

additional conservatism in the analysis is the use of the magnitude 6.0 relationship for rmining the cyclic stress ratio. The SSE at the site is based on an Intensity VI-VII earthquake, ch corresponds to a magnitude of approximately 5.3, using relationships developed by enberg and Richter (1942).

factor of safety against liquefaction at various depths for each analysis is presented on ure 2.5.4-49. It can be concluded that liquefaction would not occur in the beach and glacial wash sands adjacent to the circulating and service water pumphouse, and that the shorefront is le against sliding failures due to liquefaction of the sand. The stability against sliding of the refront during the SSE is discussed in Section 2.5.5.2.

4.8.3.3 Liquefaction Analyses of Beach Area Sands using 2-Dimensional Dynamic Response Analysis uefaction analyses performed on the sands at the shorefront and discussed in tions 2.5.4.8.3.1 and 2.5.4.8.3.2 were based on the assumption that the subsurface conditions his area could be modeled conservatively as a 40-foot deep uniform sand layer overlying 5 feet asal till and bedrock. An additional analysis was performed in which the sloping bedrock and und surfaces to the west of the circulating and service water pumphouse were incorporated a 2-dimensional dynamic response model to determine earthquake-induced shear stresses.

section selected for the 2-dimensional dynamic response model is similar to the slope ility profile shown on Figure 2.5.5-4. The liquefaction potential of the saturated glacial wash sands was determined by comparing the induced effective shear stresses calculated from dynamic model with the dynamic shear strength of the sand available to resist initial efaction previously determined from corrected blowcount values obtained from standard etration tests performed on beach area borings.

computer program PLAXLY (Plane Strain Dynamic Finite Element Analysis of Soil-cture Systems) was used to calculate earthquake-induced shear stresses within the soil profile.

initial value of low strain shear modulus and damping, total unit weight, and Poisson's ratio he elements were assigned in accordance with the following table.

Depth Gmax Damping Unit Wt Poisson's Soil Type (ft) (ksf) (min) (pcf) Ratio Outwash Sand 0-10 600 0.02 123 0.49 10-20 1,250 0.02 123 0.49 20-30 1,500 0.02 119 0.49 30-40 1,800 0.02 119 0.49 Basal Till 20,160 0.02 145 0.40 Bedrock 216,000 165 0.40 Armor Stone 0-14 900 150

strain compatible shear moduli and damping ratios of the soil were determined through a es of iterations within the PLAXLY program. The time histories of the four earthquakes listed w were normalized to the site SSE peak acceleration of 0.17g and input at the rigid base of the del. These earthquake records were selected because they were recorded at rock sites or stiff sites and therefore would be expected to approximately match dynamic response at the lstone site.

Taft S69E 1952 Kern County Earthquake Helena N-S 1935 Montana Earthquake Pacoima Dam S16F 1971 San Fernando Earthquake Temblor N65W Parkfield Earthquake profile used in the analysis is shown on Figure 2.5.4-75.

uefaction potential was calculated at each element for the six sections shown on this figure.

results of the PLAXLY analysis and the calculated values of safety factor against liquefaction presented in Table 2.5.4-25.

blowcount data used in Sections 1 to 5 were obtained from onshore borings in the shorefront

. The blowcount data from boring I21 was used to represent soil conditions in Section 6 ause the borings indicate that the sands offshore are denser than the onshore sands. The amic shear strength of the sand was calculated by determining the corrected blowcount (N1) ccordance with methods established by Gibbs and Holtz (1957), in which the corrected wcount data are corrected for an effective overburden stress of 1 tsf. The N1 values are plotted h vertical effective stress on Figures 2.5.4-28 and 2.5.4-29. The mean value of N1 was ulated from these data and used to determine the cyclic stress ratio to resist initial liquefaction m the Seed, et al, (1975) curve presented on Figure 2.5.4-48. The curve for Magnitude 6 hquakes was used to obtain a nonliquefaction cyclic stress ratio of 0.27, which was used in the lyses performed on Sections 1 to 5. For Section 6, a mean N1 value of 28 was calculated and a ss ratio of 0.42 was used in the liquefaction analysis.

earthquake-induced shear stresses were computed by averaging the peak shear stress values ined for each of the four earthquakes at each element in the PLAXLY model. The effective ar stress was obtained by multiplying the average of the four peak values by a factor of two-ds. Seed and Idriss (1971) recommend multiplying the absolute maximum shear stress value factor of 0.65 to obtain the equivalent uniform cyclic shear stress. This value was compared h the dynamic shear strength of the soil at each element to obtain the safety factor against efaction.

results of the analyses, presented in Table 2.5.4-25, indicate that the safety factor for ments 1 to 5 are all greater than 1.25. Low safety factors were determined for Section 6, mainly ause of the low vertical effective stress near the surface of the intake channel at elevation -29

nomenon limited to the intake channel only. The post-earthquake slope stability analysis ented in Section 2.5.5.2.1 was reanalyzed to consider the effect of liquefaction of the sand in intake channel (Soil 7 on Figure 2.5.5-4) on stability of the shorefront slopes. The ulations show no change in the safety factor of the critical failure circle, indicating that the refront slopes would not fail in the event that the sand in the intake channel would liquefy.

an be concluded from these analyses that liquefaction of the shorefront slopes would not occur that liquefaction of the intake channel bottom would not affect the integrity of the shorefront es adjacent to the circulating and service water pumphouse or result in a condition that would e the service water system inoperable. The soil underlying the service water pipe encasement cent to the pumphouse is not susceptible to liquefaction.

servatively postulating that liquefaction could occur during the site SSE, a study was made to rmine whether sliding of the slope into the intake channel would cause blockage of the ice water intake pumps. Data from slides caused by liquefaction during the Alaskan thquake of 1964, (Seed, 1968) indicate that flow slides maintain a slope steeper than 5 percent.

uming that the saturated sand overlying basal till adjacent to the pumphouse liquefies and s toward the intake channel, with a final slope of 5 percent, then it can be shown that 7 feet of er remains available for suction below the pump intakes. Therefore, it can be concluded that n in the highly unlikely event that liquefaction of the glacial outwash sands were to occur, the t would have an adequate supply of water available for cooling of safety-related systems.

4.8.4 Ablation Till circulating water discharge tunnel extends 1,700 feet from the main plant area to the lstone quarry east of Millstone 1. For approximately 1,200 feet, the tunnel is founded on rock. However, in the vicinity of the ventilation stack north of Millstone 1, bedrock drops ply to a trough. The maximum thickness of the overburden in this trough is approximately 60

. Borings 402 through 412 were drilled in this area to determine the subsurface conditions. A s-section of the trough along the discharge tunnel is presented on Figure 2.5.4-51. The tion of the section is shown on Figure 2.5.4-31. In this area, which extends for approximately feet, the fill and alluvium overlying the ablation and basal tills were excavated and replaced h crushed stone and concrete fill to the base elevation of the discharge tunnel. Because the tion till is a sandy material below the groundwater table, the liquefaction potential was lyzed. The analysis described in Section 2.5.4.8.4.1 shows that liquefaction of the ablation till ot possible under the site SSE. The structural fill and basal till have been shown to be liquefiable in Sections 2.5.4.8.1 and 2.5.4.8.2, respectively.

4.8.4.1 Dynamic Response Analysis of Ablation Till dynamic response of the ablation till has been evaluated to determine earthquake-induced ar stresses caused by ground motions applied at the bedrock surface and amplified through the profile. This evaluation was made using the computer program SHAKE, similar to the lysis in Section 2.5.4.8.3.1.

ountered in boring 411, which encountered the deepest rock, and represents the most servative profile in the study area. The generalized soil profile (Figure 2.5.4-50) used in the lysis of the tunnel consisted of 5 feet of structural fill, 13 feet of ablation till, and 22 feet of al till. Groundwater level was established at 10 feet below the ground surface, elevation +4

, based upon the average groundwater levels measured in borings 407 and 411. (See ure 2.5.4-31 for locations). The shear moduli values of the soils were obtained from cross-tests described in Section 2.5.4.4.3. The values of shear modulus (G) and damping (D) for strain levels used in the SHAKE analysis for each layer are:

Layer Elevation (ft) Depth (ft) Soil Type Gmax (ksf) Dmax (%)

1 +14 to -8 0-22 Discharge Tunnel -- 0.5 2 -8 to -13 22-27 Structural Fill 1.93 x 103 0.5 3 -13 to -26 27-40 Ablation Till 1.30 x 103 0.5 4 -26 to -48 40-62 Basal Till 2.0 x 104 0.5 reduction of Gmax with strain was performed through a series of iterations similar to the hod described in Section 2.5.4.8.3.1 using the same earthquake records normalized to 0.17g.

s analysis indicated that the average maximum shear stress in the ablation till induced by the

, varied from 515 psf to 533 psf. The average shear stress is assumed to be 0.65 of the peak e.

4.8.4.2 Liquefaction Analysis of Ablation Till cedures used for liquefaction analysis of the ablation till were similar to the empirical roach described in Section 2.5.4.8.3.2.

ndard penetration resistance data (N1 values) were related to liquefaction potential in ordance with methods developed by Seed, Arango, and Chan (1975) and DeAlba, Chan, and d (1975). N1 values for the ablation till were obtained from borings taken at the discharge nel location (400 series) and samples of ablation till from the main plant borings (300 series).

rage corrected blow count values and average N1 values less one standard deviation (N1-):

Midpoint of Induced Layer Shear Shear Shear Elevation Stress Strength Strength (ft) (psf) Mean N1 (psf) F.S. N1- (psf) F.S.

-15.2 515 28.7 1,079 2.10 15.5 578 1.12

-19.5 531 28.7 1,218 2.29 15.5 652 1.23

-23.9 533 28.7 1,357 2.60 15.5 726 1.36 an be concluded, therefore, that the ablation till under the discharge tunnel is not susceptible to efaction, even considering the ultraconservative case of the shear strength calculated from the n corrected blow count less one standard deviation.

4.9 EARTHQUAKE DESIGN BASIS afe shutdown earthquake of 0.17g and a 1/2 SSE value of 0.09g in the horizontal direction and

-thirds of these values in the vertical direction, input at the bedrock surface, have been used as design bases for seismic loading at the site. The derivation of these values is described in tions 2.5.2.6 and 2.5.2.7.

structures founded on soils, amplification effects have been considered by means of a soil-cture interaction analysis using the computer program PLAXLY-3 described in detail in tion 3.7.2.4.

the liquefaction analysis of the beach sands adjacent to the circulating and service water phouse, the SSE value of 0.17g was input at the bedrock surface, and the average amplified und motion at the surface determined from the SHAKE program using three earthquake rds and described in Section 2.5.4.8.3.1 was calculated to be 0.27g. Consequently, a value of g was conservatively used for the entire soil column as the average seismic loading of reline slopes in the stability analysis described in Section 2.5.5.2.

4.10 STATIC STABILITY 4.10.1 Bearing Capacity le 2.5.4-14 summarizes the bearing pressures for mats or individual spread footings founded arious foundation materials.

selection of the bearing capacity values used in footing design were based on the bearing acity formulae (Terzaghi and Peck 1967, Vesic 1975) for an estimated angle of internal friction basal till equal to 40 degrees and for structural backfill equal to 34 degrees. The total unit

les varying from 35 to 41.5 degrees for the structural fill compacted to 95 percent of the imum modified Proctor density. Inputting the relevant soil parameters described above, and ng into account the effect of the groundwater table, the bearing capacity formula for square ings or mats on basal till reduces to:

qall = 1.9 D + 1.1 B (2.5.4-6) qall (max) = 12 ksf structural backfill:

qall = 0.9 D + 0.4 B (2.5.4-7) qall (max) = 8 ksf re:

qall = Allowable bearing capacity in ksf with a minimum safety factor = 3 D = Depth of embedment (feet)

B = Width of footing (feet) le 2.5.4-24, Bearing Capacity of Major Structures, presents a summary of the allowable ring capacity for the material beneath each structure. In all cases, the factor of safety is greater 3, which is the minimum required value.

ed on Teng (1962), the design bearing capacity of foundations on rock is commonly taken as to 1/8 of the crushing strength (factor of safety of 5 to 8). A value of 200 ksf was selected for maximum allowable bearing capacity of bedrock at the site. This corresponds to roximately 1/7 of the average unconfined compressive strength of approximately 1,440 ksf 000 psi) reported in Table 2.5.4-10. The 200 ksf value also corresponds to the presumptive ace bearing value given by the Connecticut Basic Building Code (1978) for massive talline rock, including granite and gneiss.

m Table 2.5.4-14, the maximum average foundation pressure for a structure on rock is 8 ksf.

s, the factor of safety against a bearing capacity failure is much greater than 3 for all structures nded on rock.

4.10.2 Settlement of Structures k and soil supported Seismic Category I structures experience only elastic displacements er the design loads. Analyses using linear elasticity principals, assuming rigid foundations, cate that the vertical settlements of structures founded on rock are very small under the design s, as shown by the summary included in Table 2.5.4-14.

71). The main steam valve, auxiliary, and engineered safety features buildings, founded on k, were analyzed using equations for rigid rectangular mats on a semi-infinite mass developed Whitman and Richart (1967). Structures founded totally or partly on soil, such as the control, rgency diesel generator enclosure, fuel, and waste disposal buildings, were analyzed using tions obtained by Sovinc (1969) for rigid rectangles on a finite layer. The settlement of the erlying rock layer was also estimated using the Whitman and Richart equations.

stic properties of the rock and basal till are discussed in Section 2.5.4.4.3. The elastic modulus for static strain levels was estimated equal to 10,000 psi, as discussed in Section 2.5.4.5.2.

le 2.5.4-14 indicates that the maximum estimated settlement within any one structure occurs he emergency generator enclosure building and is equal to 0.40 inch. Most of this settlement lts from the conservative assumption that the south footing of the EGE is founded on 9 feet of ctural fill. Maximum estimated differential settlement between adjacent structures occurs ween the control building and the emergency generator enclosure building, and is equal to ut 0.40 inch. The rate of these settlements would essentially be the same as the rate of loading ause of elastic nature of the bearing material.

4.10.3 Lateral Earth Pressures magnitude and distribution of lateral earth pressures is a function of the allowable yielding of wall, the backfill material characteristics, water pressure, surcharge loads from adjacent ctures, and, for seismically designed structures, the earthquake loading. The concrete ndation walls were conservatively assumed to be rigid, unyielding walls. Therefore, the fficient of earth pressure at rest, Ko, has been used in evaluating lateral loads on these walls.

mpaction specifications prohibited the use of heavy vibratory compactors within 5 feet of all crete structures. Light compactors were used when backfilling against structures in order to imize residual lateral stresses in the fill due to the applied compactive effort. For the backfill e site, a value of Ko = 0.5 was used.

kfill placed behind walls consisted of well graded sands and gravels compacted to 90 percent maximum density (ASTM D1557) to minimize the horizontal loads induced by high pactive stresses. Tests on similar soils, compacted to 90 percent of maximum dry density and orted in Section 2.5.2.5.2, resulted in friction angles in excess of 34 degrees.

amic loadings include pressures due to the soil mass, water, and surcharge, accelerated in the ical and horizontal directions. Methods of analysis are based on procedures proposed by nonobe (1929), Okabe (1926), and Seed and Whitman (1970) and are graphically depicted on ure 2.5.4-43.

4.11 DESIGN CRITERIA design criteria and minimum required factors of safety for bearing capacity, hydrostatic uplift oyancy), and sliding (against lateral pressures) are summarized below:

Terzaghi and Peck 1967).

2. Hydrostatic Uplift - The determination of the buoyant force, and the weight of the structures can be made relatively precisely. Therefore, a factor of safety against hydrostatic uplifting of 1.1 was determined to be adequate under the normal water levels shown on Figure 2.5.4-37, considering the dead load of the structure only.

For high water level conditions, the dead load of the structure plus equipment load is at least 1.1 times the buoyant force of water.

3. Sliding - Either of two methods has been used to determine the factor of safety against sliding. One method considers that only frictional forces at the base resist sliding. A minimum factor of safety of 1.1 is required. The second method includes base friction and the resisting force due to passive earth pressure. For this method, a minimum factor of safety of 2.0 is required.

iscussion of the bearing capacity analysis is included in Section 2.5.4.10.1. The loads used for rmining lateral pressures on structures are discussed in Section 2.5.4.10.3.

design limits for the foundations of all Category I structures are discussed in the structural eptance criteria in Section 3.8.5.5.

4.12 TECHNIQUES TO IMPROVE SUBSURFACE CONDITIONS Category I structures are founded on either high quality, intact rock, undisturbed basal till, or pacted, select granular fill. Therefore, no improvement of the founding material below any cture was required.

k dowels were installed around the periphery of the auxiliary building to provide stability ng seismic loading. These dowels consist of 2 1/4-inch diameter, grade 60 steel bar with 10 s of fusion bonded epoxy coating for double corrosion protection. The dowels were designed ct as a passive support system, with stressing occurring only during seismic loading. Six test els of varying lengths were loaded to the yield strength of the bar (240 kips) to verify design meters.

k anchors were installed in the turbine building to provide resistance to overturning due to ado loading. These anchors consisted of a 1 1/4-inch diameter, high strength steel bar athed in a corrugated PVC casing and fully grouted for double corrosion protection. Each hor was proof loaded to 150 kips and then the load was reduced to 125 kips for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The hor was subsequently locked off at a permanent load of 25 kips and encased in the concrete ndation mat.

k anchors were installed in the service building to provide resistance to uplift loads due to yant forces and seismic forces. These anchors consisted of 1 3/8-in diameter, high strength l bar sheathed in a corrugated PVC casing and fully grouted for double corrosion protection.

ultimate strength of each anchor is 237 kips, with a working load equal to 60 percent of the

ed off at a load of 40 kips, which corresponds to the hydrostatic uplift component of the hor design load. The remaining capacity of the anchor is mobilized during seismic loading.

porary rock bolts were installed in the southwest sector of the containment excavation face to vent potential sliding failures along the foliation planes. These bolts consisted of Grade 60 l, No. 11 reinforcing bars with a working load of 45 kips. Anchorage of the rock bolts was vided by Celtite polyester resin encapsulation.

ailed geologic mapping of bedrock surfaces at the site, described in detail in Section 2.5.4.11, tified certain preferred joint surfaces that may cause potential sliding planes with the tainment excavation face. As a result of these findings, a reinforced concrete ring beam was ed in the annular space between the excavation face and the containment exterior wall to ilize the wedges. The slope stability analysis for the containment excavation is discussed in il in Section 2.5.5.1. The structural analysis is discussed in Chapter 3.

4.13 STRUCTURE SETTLEMENT st of the Category I structures at the site are founded on sound bedrock. Predicted settlements d in Table 2.5.4-14 for these structures are very small. Settlement predictions for structures nded on basal till or structural backfill indicate that the maximum expected settlement is less 0.4 inch and that this settlement occurs over a relatively short period of time due to the elastic re of the subsurface materials. Settlement has been monitored for the control, fuel, waste osal, and emergency generator enclosure buildings during construction. A plan of the location he settlement monitoring benchmark locations is shown on Figure 2.5.4-59. Plots of observed y settlement versus time for these structures are presented in Figures 2.5.4-60 through 2.5.4-The records show no significant movement of any structure, although some heave has urred due to rebound from excavation. Settlement of these structures has been periodically sured, and it has been determined that there does not appear to be any significant movement he monitoring points. Records of these measurements are being maintained, in accordance h Procedure No. SP-CE-223, as permanent plant records.

4.14 CONSTRUCTION NOTES significant problems were encountered during construction that required extensive redesign of ctures. A small amount of basal till was excavated and replaced with structural backfill eath the control building due to inflow of groundwater during excavation. This occurrence is ussed in detail in Section 2.5.4.5.1.

concrete backfill in the annular space between the containment exterior wall and the avation face was modified because of data obtained from the geologic mapping program. The crete backfill was revised to be a reinforced concrete structural support to resist the potential ure of rock wedges subjected to seismic loading and maintain the isolation of the containment cture from external forces. This ring beam is discussed in detail in Sections 2.5.5.1 and 5.3.

4.1-1 Bechtel Corporation, 1969. Subsurface, Geophysical, and Groundwater Investigations. In: Preliminary Safety Analysis Report, Millstone Nuclear Power Station - Unit 2.

4.1-2 Butterfield, R. and Banjerjee, P. K. 1971. A Rigid Disc Embedded in an Elastic Half Space. Geotechnical Engineering, Vol 2, No. 1, p 35-52.

4.1-3 Dale, T. N. 1923. The Commercial Granites of New England. U.S. Geol. Survey, Bulletin 738, p 448.

4.1-4 Dale, T. N. and Gregory, H. E. 1911. The Granites of Connecticut. U.S. Geol.

Survey, Bulletin 484, p 109-122.

4.1-5 DeAlba, P.; Chan, C. K.; and Seed, H. B. 1975. Determination of Soil Liquefaction Characteristics by Large-Scale Laboratory Tests. Earthquake Engineering Research Center, Report No. EERC 75-14, University of California, Berkeley, Calif.

4.1-6 Ebasco Services, Inc. 1966. Geology and Seismology. In: Design Analysis Report.

Millstone Nuclear Power Station - Unit No. 1, Section 5.0.

4.1-7 Gibbs, H. J. and Holtz W. G. 1957. Research on Determining the Density of Sands by Spoon Penetration Testing. Proceedings, Fourth International Conference on Soil Mechanics and Foundation Engineering, Vol 1, London, England, p 35-39.

4.1-8 Gutenberg, B. and Richter, C. F. 1942. Earthquake Magnitude, Intensity, Energy, and Acceleration. Seismological Society of American Bulletin, Vol 32, p 163-191.

4.1-9 Hardin, B. O. and Black, W. L. 1968. Vibration Modulus of Normally Consolidated Clay. Journal of the Soil Mechanics and Foundation Division, ASCE, Vol 94, No.

SM2.

4.1-10 Hardin, B. O. and Richart, F. E., Jr. 1963. Elastic Wave Velocities in Granular Soils.

Journal of the Soil Mechanics and Foundation Engineering Division, ASCE, Vol 89, SM1.

4.1-11 Kishida, H. 1966. Damage to Reinforced Concrete Buildings in Niigata City with Special Reference to Foundation Engineering. Soils and Foundations, Vol VI, No. 1, p 71-88.

4.1-12 Kishida, H. 1969. Characteristics of Liquefied Sand during Mino-Owari, Tohnankai, and Fuklai Earthquakes. Soils and Foundations, Vol IX, No. 1, p 75-92.

4.1-13 Koizumi, Y. 1966. Change in Density of Sand Subsoil Caused by the Niigata Earthquake Records. Transactions of the Architectural Institute of Japan,

4.1-14 LaPlante, F. and Christian, J. T. 1974. Earthquake Response Analysis of Horizontally Layered Sites (SHAKE). Stone & Webster Engineering Corporation, Computer Department User's Manual, ST-211, Boston, Mass.

4.1-15 Lee K. L. and Fitton, J. A. 1969. Factors Affecting the Cyclic Loading Strength of Soil. In: Vibration Effects of Earthquakes on Soils and Foundations. ASTM STP450, American Society of Testing and Materials.

4.1-16 Lee, K. L. and Seed, H. B. 1967. Cyclic Stress Conditions Causing Liquefaction of Sand. Journal of the Soil Mechanics and Foundations Engineering Division. ASCE, Vol 93, No. SM1.

4.1-17 Mononobe, N. 1929. Earthquake-Proof Construction of Masonry Dams.

Proceedings, World Engineering Conference, Vol 9, p 275.

4.1-18 Niles, W. H. 1975-76. Geological Agency of Lateral Pressure Exhibited by Certain Movements of Rocks. Proc. Boston Soc. of Natural History, Vol 18, p 279.

4.1-19 Northeast Nuclear Energy Company (NNECo.) 1975. Geologic Mapping of Bedrock Surface. Millstone Nuclear Power Station-Unit 3, Docket No. 50-423, Waterford, Conn.

4.1-20 Northeast Nuclear Energy Company (NNECo.) 1976. Report on Small Fault in Warehouse No. 5 - Unit 2 Condensate Polishing Facility. Millstone Nuclear Power Station-Unit 3, Docket No. 50-423, Waterford, Conn.

4.1-21 Northeast Nuclear Energy Company (NNECo.) 1977. Fault in Demineralized and Refueling Water Tank Area. Millstone Nuclear Power Station-Unit 3, Docket No.

50-423, Waterford, Conn.

4.1-22 Okabe, S. 1926. General Theory of Earth Pressure. Journal, Japanese Society of Civil Engineers, Vol 12, No. 1.

4.1-23 Seed, H. B. 1968. Landslides during Earthquakes Due to Liquefaction. Journal of the Soil Mechanics and Foundation Engineering Division, ASCE, Vol 94, No. SM5.

4.1-24 Seed, H. B.; Arrango, I.; and Chan, C. K. 1975. Evaluation of Soil Liquefaction Potential during Earthquakes. Earthquake Engineering Research Center, Report No.

EERC 75-28, University of California, Berkeley, Calif.

4.1-25 Seed, H. B. and Idriss, I. M. 1967. Analysis of Soil Liquefaction: Niigata Earthquake. Journal of the Soil Mechanics and Foundation Engineering Division, ASCE, Vol 93, No. SM3.

ASCE, Vol 97, No. SM9.

4.1-27 Seed, H.B.; Idriss, I.M.; Makdisi, F. and Banjeree, N.R. 1975. Representation of Irregular Stress Time Histories by Equivalent Uniform Stress Series in Liquefaction Analysis. Earthquake Engineering Research Center, Report No. EERC 75-29; University of California, Berkeley, Calif.

4.1-28 Seed, H. B. and Lee, K. L. 1966. Liquefaction of Saturated Sands during Cyclic Loading. Journal of the Soil Mechanics and Foundation Engineering Division.

ASCE, Vol 92, No. SM6.

4.1-29 Seed, H. B. and Whitman, R. V. 1970. Design of Earth Retaining Structures for Dynamic Loading. Proceedings, ASCE Specialty Conference on Lateral Stresses and Design of Earth Retaining Structures, Cornell University, Ithaca, NY.

4.1-30 Shannon and Wilson Inc. and Agbabian-Jacobsen Associates. 1972. Soil Behavior Under Earthquake Loading Conditions. Report prepared by Union Carbide Corporation for U.S. Atomic Energy Commission.

4.1-31 Sovinc, I. 1969. Displacements and Inclinations of Rigid Footings Resting on a Limited Elastic Layer of Uniform Thickness. Proceedings of the Seventh International Conference on Soil Mechanics and Foundation Engineering, Vol 1, p 385-389.

4.1-32 State of Connecticut, Basic Building Code, Seventh Edition, 1978. Building Officials and Code Administrators International, Inc. Homewood, Illinois.

4.1-33 Teng, W.C. 1962. Foundation Design, Prentice Hall, Inc., Englewood Cliffs, New Jersey.

4.1-34 Terzaghi, K. and Peck, R. 1967. Soil Mechanics in Engineering Practice. Second Edition, John Wiley and Sons, Inc., New York, NY.

4.1-35 Vesic, A. S. 1975. Bearing Capacity of Shallow Foundations. In: Foundation Engineering Handbook. Wenterkon, H. F. and Fang, H. Y. (ed.) Van Nostrand-Reinhold, New York, NY.

4.1-36 Whitman, R. V. and Richart, F. E., Jr. 1967. Design Procedures for Dynamically Loaded Foundations. Journal of the Soil Mechanics and Foundation Engineering Division, ASCE, Vol 93, No. SM6.

TABLE 2.5.4-1 LIST OF JOINTS - FINAL GRADE FLOORS OF STRUCTURES CLICK HERE TO SEE TABLE 2.5.4-1

BLE 2.5.4-2 LIST OF FOLIATIONS - FINAL GRADE FLOORS OF STRUCTURES CLICK HERE TO SEE TABLE 2.5.4-2

TABLE 2.5.4-3 LIST OF SLICKENSIDES - FINAL GRADE FLOORS OF STRUCTURES CLICK HERE TO SEE TABLE 2.5.4-3

TABLE 2.5.4-4 LIST OF JOINTS - FINAL GRADE CONTAINMENT AND ENGINEERED SAFETY FEATURES BUILDING WALLS CLICK HERE TO SEE TABLE 2.5.4-4

TABLE 2.5.4-5 LIST OF FOLIATIONS - FINAL GRADE CONTAINMENT AND ENGINEERED SAFETY FEATURES BUILDING WALLS CLICK HERE TO SEE TABLE 2.5.4-5

TABLE 2.5.4-6 LIST OF SLICKENSIDES - FINAL GRADE CONTAINMENT AND ENGINEERED SAFETY FEATURES BUILDING WALLS CLICK HERE TO SEE TABLE 2.5.4-6

TABLE 2.5.4-7 LIST OF JOINTS - FINAL GRADE WALLS OF STRUCTURES CLICK HERE TO SEE TABLE 2.5.4-7

ABLE 2.5.4-8 LIST OF FOLIATIONS - FINAL GRADE WALLS OF STRUCTURES CLICK HERE TO SEE TABLE 2.5.4-8

TABLE 2.5.4-9 LIST OF SLICKENSIDES - FINAL GRADE WALLS OF STRUCTURES CLICK HERE TO SEE TABLE 2.5.4-9

TABLE 2.5.4-10 ROCK COMPRESSION TEST RESULTS CLICK HERE TO SEE TABLE 2.5.4-10

ABLE 2.5.4-11 DIRECT SHEAR TEST RESULTS FROM JOINT AND FOLIATING SURFACES CLICK HERE TO SEE TABLE 2.5.4-11

Boring No. Sample Depth (ft) Elev (ft msl) t (lb/cu ft) Water Content (%) d (lb/cu ft) Gs Su (ksf) f (de P3 UP4A2 32.0 -18.65 117.2 32.9 88.2 2.75 1.9 33 P4 UP1A2 5.0 -01.13 114.9 29.8 88.5 2.76 1.6 41 P7 UP3A2 29.6 -25.80 116.3 32.9 87.5 2.77 2.2 35 P8 UP1A 12.0 -01.48 122.1 12.3 108.7 - 1.3 27

• Table 3 in Appendix 2.5F gives data on dynamic properties.

TABLE 2.5.4-13 NATURAL WATER CONTENTS OF SPLIT SPOON SAMPLES CLICK HERE TO SEE TABLE 2.5.4-13

Maxi Average Calcu Static Average Thickness Design Sta Bearing Founding Founding Thickness Till Structural Dimensions of Groundwater Settle Structure Load (psf) Grade (ft) Material (ft) Fill (ft) Foundation (ft) Elevation (ft) (in Containment 7,480 -38.7 Rock - - 158 diameter 21 0.04 Main Steam 5,000 +9.0 Rock - - 70 x 60 19 0.01 Valve Auxiliary 4,860 -0.5 Rock - - 177 x 102 23 0.02 Engineered 3,050 -0.5 Rock - - 139 x 47 21 0.01 Safety Features Control 3,810 -0.5 Till 0 to 10 - 120 x 103 19 0.02 to Emergency 3,070 +9.0 Till 10 10 Strip 19 0.01 to Generator Enclosure (EGE)

Emergency 1,230 +1.5 Till 10 4 65 x 32 19 less th Generator Oil 0.01 Tank Emergency 1,500 +18.50 Structural 17 9.5 44 x 12 19 0.25 Generator Backfill Mats Refueling 4,000 +15.0 Rock - - Octagon 64 - less th Water Storage inside diameter 0.01 Tank

Maxi Average Calcu Static Average Thickness Design Sta Bearing Founding Founding Thickness Till Structural Dimensions of Groundwater Settle Structure Load (psf) Grade (ft) Material (ft) Fill (ft) Foundation (ft) Elevation (ft) (in Demineralize 4,000 +14.5 Rock - - Octagon 40 - less th d Water inside diameter 0.01 Storage Tank Fuel 4,500 +3.0 Rock - - 93 x 112 23 less th 0.01 Waste 4,500 +0.5 Till 2 to 8 114 x 48 23 0.02 Disposal (Liquid)

Waste 3,030 +19.5 Structural 23 7 114 x 38 23 0.25 Disposal Backfill (Solid)

Hydrogen 4,490 +20.0 Concrete Fill - - 56 x 50 18 less th Recombiner 0.01 NOTE: All foundations are structural mat except EGE which is strip footing and slab on grade.

ELEVATIONS *

(SEE BOTH LOGS (Appendix 2.5J) FOR EXACT VALUES)

(Changes made to this table in 1997 correct transcription errors associated with the original submission.)

Site Coordinates Surface Groundwater Elevation Depth Drilled Top of Rock Boring No. North/South East/West (ft) (ft) Elevation (ft) Elevation (ft) Dat 301 N1562 E505 28.4 36.0 12.4 20.4 12-15-71 302 N1458 E421 28.2 75.0 15.7 17.7 12-22-71 303 N1635 E335 29.3 30.0 19.3 22.8 12-18-71 304 N1533 E371 28.5 75.0 14.5 19.5 12-21-71 305 N1448 E347 26.2 125.0 7.2 17.0 12-21-71 306 N1383 E346 24.1 75.0 10.6 12.6 12-15-71 307 N1558 E258 28.4 37.5 18.4 19.2 12-13-71 308 N1446 E267 24.8 75.0 14.8 18.0 12-17-71 309 N1632 E167 27.3 48.0 -0.7 17.3 12-13-71 310 N1433 E185 25.6 45.0 1.6 17.0 12-24-71 311 N1232 E213 20.9 50.0 -9.1 8.6 12-21-71 312 N1544 E123 25.9 65.0 -20.1 15.9 12-29-71 313 N1388 E113 22.7 66.5 -23.8 15.9 12-28-71 314 N1628 E062 24.9 53.0 -8.1 15.9 12-14-71 315 N1433 E076 23.3 63.0 -19.7 14.2 12-23-71 316 N1270 W010 15.6 53.0 -17.4 6.4 12-30-71

(SEE BOTH LOGS (Appendix 2.5J) FOR EXACT VALUES)

(Changes made to this table in 1997 correct transcription errors associated with the original submission.)

Site Coordinates Surface Groundwater Elevation Depth Drilled Top of Rock Boring No. North/South East/West (ft) (ft) Elevation (ft) Elevation (ft) Dat 317 N1446 E322 25.3 74.5 15.8 16.6 12-27-71 318 N1415 E115 25.0 67.0 -22.5 16.3 01-12-72 319 N1708 E065 25.0 79.3 -10.2 16.6 11-11-72 320 N1705 E183 28.3 26.0 12.5 20.6 11-02-72 321 N1808 E174 27.6 71.1 -19.0 13.1 11-03-72 322 N1808 E264 30.3 35.0 6.3 22.2 10-31-72 323 N1708 E264 29.3 32.0 12.3 21.1 10-30-72 324 N1718 E364 30.1 51.3 -4.9 21.6 10-26-72 325 N1718 E476 30.1 47.0 -6.7 21.3 10-18-72 326 N1432 E476 27.0 85.3 17.9 16.5 10-10-72 327

• N1510 E456 28.7 111.3 20.8 20.8 11-02-72 328

• N1593 E384 29.1 144.3 10.5 16.4 10-12-72 329

• N1520 E369 28.1 120.7 13.2 15.3 10-26-72 330

• N1521 E309 28.2 106.0 19.4 20.8 11-15-72 331

• N1460 E375 27.4 112.5 9.0 18.3 11-07-72 I-1 N1720 W980 18.1 31.5 7.6 6.6 12-31-71 I-2 N1520 W450 9.3 68.5 -38.2 1.3 01-14-72

(SEE BOTH LOGS (Appendix 2.5J) FOR EXACT VALUES)

(Changes made to this table in 1997 correct transcription errors associated with the original submission.)

Site Coordinates Surface Groundwater Elevation Depth Drilled Top of Rock Boring No. North/South East/West (ft) (ft) Elevation (ft) Elevation (ft) Dat I-3 N1097 W370 0.6 48.4 -34.2 -1.2 11-17-72 I-4 N1260 W200 16.5 50.3 -9.0 1.1 11-15-72 I-5 N1470 W20 20.1 75.0 -22.9 7.8 11-08-72 I-6 N1529 W150 20.3 46.5 -11.2 6.3 09-10-73 I-7 N1388 W205 18.2 47.0 -13.9 3.2 09-06-73 I-8 N1257 W310 14.7 58.5 -28.8 0.6 09-07-73 I-8A N1258 W307 14.8 18.0 I-9 N1225 W538 7.4 55.5 -30.6 I-10 N1148 W409 5.0 60.9 -40.9 1.7 09-10-73 I-10A N1121 W368 5.4 19.2 I-11 N1073 W279 7.1 60.0 -10.9 1.1 09-12-73 I-12 N0989 W171 9.0 29.0 -5.0 2.5 09-14-73 I-14 N1020 W485 -4.5 36.8 -41.3 Offshore I-15 N0948 W394 -4.6 51.8 -40.6 Offshore I-19A N0837 W272 -12.0 22.4 -19.4 Offshore I-20 N0970 W692 -10.8 55.1 -52.9 Offshore I-21 N0902 W574 -11.0 61.0 -57.0 Offshore

(SEE BOTH LOGS (Appendix 2.5J) FOR EXACT VALUES)

(Changes made to this table in 1997 correct transcription errors associated with the original submission.)

Site Coordinates Surface Groundwater Elevation Depth Drilled Top of Rock Boring No. North/South East/West (ft) (ft) Elevation (ft) Elevation (ft) Dat I-22 N0814 W433 -20.0 45.3 -56.3 Offshore I-23 N0836 W766 -14.1 22.5 -27.1 Offshore I-24 N0708 W679 -17.7 38.2 -40.9 Offshore DT-1 N0980 E580 15.1 44.5 -9.4 5.0 12-30-71 DT-2 N0250 E1040 9.8 150.0 1.8 3.3 01-11-72 DT-3 S0690 E1360 10.6 150.0 3.6 3.6 01-07-72 401 N1303 E487 21.9 35.3 0.2 12.2 06-04-74 402 N0950 E840 16.4 28.0 -0.1 8.9 06-04-74 403 N0710 E925 12.8 60.7 -33.7 404 N0388 E924 11.7 36.2 -4.4 405 N0301 E720 17.7 42.6 9.9 13.0 05-29-74 406 N800 E924 14.03 44.5 -20.5 6.03 04-30-80 407 N625 E924 14.94 65.0 -45.1 4.94 04-30-80 408 N788.12 E879.83 14.36 45.0 -29.1 - -

409 N782.27 E870.02 14.54 39.0 -19.5 5.54 05-02-80 410 N775.21 E860.03 14.36 39.0 -19.6 - -

411 N519.2 E922.6 13.94 64.5 -47.6 3.44 05-08-80

(SEE BOTH LOGS (Appendix 2.5J) FOR EXACT VALUES)

(Changes made to this table in 1997 correct transcription errors associated with the original submission.)

Site Coordinates Surface Groundwater Elevation Depth Drilled Top of Rock Boring No. North/South East/West (ft) (ft) Elevation (ft) Elevation (ft) Dat 402 N463.6 E921.2 13.34 57.0 -35.2 - -

P-1 N1037 W313 1.4 28.7 -22.3 P-2 N1109 W415 3.0 48.8 -41.0 P-3 N1188 W383 13.4 58.6 -40.3 P-4 N1046 W270 3.9 19.5 -10.6 P-5 N1010 W218 5.6 16.0 -5.4 P-6 N1068 W207 17.7 28.0 -5.3 P-7 N1165 W495 3.8 43.0 -34.2 P-8 N1315 W705 10.5 45.5 -30.0 P-9 N1292 W825 7.2 12.5 -0.3 P-10 N1254 W770 4.4 21.7 -12.3 T-1 N1287 E428 21.1 31.5 -1.4 T-2 N1234 E465 19.2 31.0 -3.3 T-3 N1234 E428 19.8 38.0 -8.2 T-4 N1159 E388 16.9 38.7 -16.8 T-5 N1208 E308 17.9 36.0 -4.1 T-6 N1250 E309 20.2 27.0 -1.8

(SEE BOTH LOGS (Appendix 2.5J) FOR EXACT VALUES)

(Changes made to this table in 1997 correct transcription errors associated with the original submission.)

Site Coordinates Surface Groundwater Elevation Depth Drilled Top of Rock Boring No. North/South East/West (ft) (ft) Elevation (ft) Elevation (ft) Dat T-7 N1186 E220 20.6 42.0 -7.4 Q-1 N0097 E323 2.7 50.0 -36.3-42.8 Offshore Q-2 N0095 E294 3.3 55.0 -46.7 Offshore Q-3 N0009 E330 -5.0 33.0 -33.0 Offshore Q-4 N0002 E299 -5.8 42.0 -42.8 Offshore B-1 N1175 E061 19.3 34.5 -8.2 B-2 N1172 E60.5 19.8 50.0 -25.2 B-3 N1109 E152 14.8 33.5 -13.7 B-4 N1059 E152 16.9 41.0 -17.6 B-5 N1012 E120 16.6 21.5 0.5 B-6 N1066 E061 17.0 21.0 2.5 NOTE:

• 45 degree angle boring

TABLE 2.5.4-16

SUMMARY

OF WATER PRESSURE TEST DATA CLICK HERE TO SEE TABLE 2.5.4-16

TABLE 2.5.4-17 GROUNDWATER OBSERVATIONS CLICK HERE TO SEE TABLE 2.5.4-17

TABLE 2.5.4-18 FACTORS OF SAFETY AGAINST LIQUEFACTION OF BEACH SANDS CLICK HERE TO SEE TABLE 2.5.4-18

TABLE 2.5.4-19 IN-PLACE DENSITY TEST RESULTS ON CATEGORY I STRUCTURAL BACKFILL BENEATH THE SERVICE WATER INTAKE PIPE ENCASEMENT CLICK HERE TO SEE TABLE 2.5.4-19

TABLE 2.5.4-20 IN-PLACE DENSITY TEST RESULTS AT CONTROL AND EMERGENCY GENERATOR ENCLOSURE BUILDINGS CLICK HERE TO SEE TABLE 2.5.4-20

ANALYSIS Taft Helena Parkfield Top of Layer Elevatio G (2)

Layer n (ft) Soil Type t (pcf) Gmax (psi) G (1 ) (psi) G (2) (ksf) D (3) G (2) (ksf) D (3) (ksf) D 1 24 Fill 143 1.2 X 104 3810 613 0.087 457 0.140 576 0.10 2 15 Fill 143 1.63 X 104 5324 778 0.104 825 0.116 697 0.12 3 (4) 10 Basal till 145 1.4 x 105 1.28 x 105 18,800 0.014 18,715 0.014 17,968 0.01 4 0 Basal till 145 1.4 x 105 1.20 x 105 17,850 0.018 17,249 0.022 16,913 0.02 5 -10 Basal till 145 1.4 x 105 1.12 x 105 16,981 0.022 16,077 0.025 15,470 0.02 6 -20 Bedrock - 1.5 x 106 -

NOTE:

1. Gg = The average of the G's for the 3 earthquakes.

2. G = Strain corrected shear modulus (ksf).

3. D = Strain corrected damping ratio.

4. The structure is founded on the basal till at the top of Layer 3. Soil stiffness was modeled using shear modulus.

ABLE 2.5.4-22B EMERGENCY GENERATOR ENCLOSURE - SOIL PROPERTIES WITH STRUCTURE EFFECTS FROM SHAKE ANALYSIS CLICK HERE TO SEE TABLE 2.5.4-21B

ABLE 2.5.4-23 EMERGENCY GENERATOR ENCLOSURE - SOIL PROPERTIES WITH STRUCTURE EFFECTS FROM SHAKE ANALYSIS CLICK HERE TO SEE TABLE 2.5.4-22

Approximate Allowable 1 Dimensions of Approximate Approximate Ultimate Bearing Contact Area Foundation Foundation Static Bearing Capacity Facto Structure (ft) Depth (ft) Load (ksf) Capacity (ksf) (ksf) Saf Containment 158 diam 62.7 7.48 - 200 26 Main Steam Valve 70 x 60 15.0 5 - 200 40 Auxiliary 177 x 102 24.5 4.86 - 200 41 Engineered Safety Features 139 x 47 24.5 3.05 - 200 65 Control 120 x 103 24.5 3.81 488 12 128 Emergency Generator Enclosure 10 strip 15.0 3.07 128 12 41 Emergency Generator Oil Tank 65 x 32 22.5 1.23 102 8 83 Refueling Water Storage Tank Octagon 64 I.D. 9.0 4 - 200 50 Demineralized Water Storage Tank Octagon 40 I.D. 9.5 4 - 200 50 Fuel 93 x 112 21.0 4.5 - 200 44 Waste Disposal (Liquid) 114 x 48 23.5 4.5 288 12 64 Hydrogen Recombiner 56 x 50 4.0 4.49 - 200 44 Discharge Tunnel 17 wide 32.5 to 22.5 3.59 56 2 8 15 Circulating Water Pumphouse 142 x 84 46.0 4.55 - 200 44 NOTES:

1. See FSAR Section 2.5.4.10

2. Bearing capacity determined for structure on concrete fill over ablation till

BLE 2.5.4-25 RESULTS OF TWO-DIMENSIONAL LIQUEFACTION ANALYSIS OF BEACH AREA SANDS CLICK HERE TO SEE TABLE 2.5.4-24

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-1 GEOLOGIC MAP OF FINAL GRADE, SERVICE WATER LINE WALLS - EAST Revision 3606/29/23 MPS-3 FSAR 2.5.4-67

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-2 GEOLOGIC MAP OF FINAL GRADE, SERVICE WATER LINE WALLS - WEST Revision 3606/29/23 MPS-3 FSAR 2.5.4-68

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-3 GEOLOGIC MAP OF FINAL GRADE, SOUTH WALL OF DISCHARGE TUNNEL Revision 3606/29/23 MPS-3 FSAR 2.5.4-69

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-4 GEOLOGIC MAP OF FINAL GRADE, NORTH WALL OF DISCHARGE TUNNEL Revision 3606/29/23 MPS-3 FSAR 2.5.4-70

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-5 GEOLOGIC MAP OF FINAL GRADE, EAST WALL OF DISCHARGE TUNNEL Revision 3606/29/23 MPS-3 FSAR 2.5.4-71

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-6 GEOLOGIC MAP OF FINAL GRADE, FLOORS OF STRUCTURES Revision 3606/29/23 MPS-3 FSAR 2.5.4-72

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-7 GEOLOGIC MAP OF FINAL GRADE, SERVICE WATER LINE FLOOR - WEST Revision 3606/29/23 MPS-3 FSAR 2.5.4-73

Revision 3606/29/23 MPS-3 FSAR 2.5.4-74 Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-8 GEOLOGIC MAP OF FINAL GRADE, PUMPHOUSE FLOOR

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-9 GEOLOGIC MAP OF FINAL GRADE, SERVICE WATER LINE FLOOR - EAST Revision 3606/29/23 MPS-3 FSAR 2.5.4-75

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-10 GEOLOGIC MAP OF FINAL GRADE, SOUTHEAST QUADRANT OF CONTAINMENT WALLS Revision 3606/29/23 MPS-3 FSAR 2.5.4-76

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-11 GEOLOGIC MAP OF FINAL GRADE, SOUTHWEST QUADRANT OF CONTAINMENT WALLS Revision 3606/29/23 MPS-3 FSAR 2.5.4-77

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-12 GEOLOGIC MAP OF FINAL GRADE, NORTHWEST QUADRANT OF CONTAINMENT WALLS Revision 3606/29/23 MPS-3 FSAR 2.5.4-78

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-13 GEOLOGIC MAP OF FINAL GRADE, NORTHEAST QUADRANT OF CONTAINMENT WALLS Revision 3606/29/23 MPS-3 FSAR 2.5.4-79

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-14 GEOLOGIC MAP OF FINAL GRADE, ENGINEERED SAFETY FEATURES, BUILDING SUMP WALLS Revision 3606/29/23 MPS-3 FSAR 2.5.4-80

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-15 GEOLOGIC MAP OF FINAL GRADE, AUXILIARY BUILDING PIPE TUNNEL PIT WALLS Revision 3606/29/23 MPS-3 FSAR 2.5.4-81

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-16 GEOLOGIC MAP OF FINAL GRADE, NORTH WALL OF EXCAVATION Revision 3606/29/23 MPS-3 FSAR 2.5.4-82

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-17 GEOLOGIC MAP OF FINAL GRADE, NORTHEAST AND SOUTHEAST PUMPHOUSE WALLS Revision 3606/29/23 MPS-3 FSAR 2.5.4-83

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-18 GEOLOGIC MAP OF FINAL GRADE ENGINEERED SAFETY FEATURES BUILDING WALL Revision 3606/29/23 MPS-3 FSAR 2.5.4-84

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-19 GEOLOGIC MAP OF FINAL GRADE DISCHARGE TUNNEL FLOOR Revision 3606/29/23 MPS-3 FSAR 2.5.4-85

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-20 GEOLOGICAL MAP OF FINAL GRADE DISCHARGE TUNNEL FLOOR Revision 3606/29/23 MPS-3 FSAR 2.5.4-86

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-21 GEOLOGICAL MAP OF FINAL GRADE NORTH WALL OF DISCHARGE TUNNEL Revision 3606/29/23 MPS-3 FSAR 2.5.4-87

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-22 GEOLOGICAL MAP OF FINAL GRADE SOUTH WALL OF DISCHARGE TUNNEL Revision 3606/29/23 MPS-3 FSAR 2.5.4-88

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-23 GEOLOGIC MAP OF FINAL GRADE DISCHARGE TUNNEL FLOOR Revision 3606/29/23 MPS-3 FSAR 2.5.4-89

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-24 GEOLOGIC MAP OF FINAL GRADE DISCHARGE TUNNEL FLOOR Revision 3606/29/23 MPS-3 FSAR 2.5.4-90

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-25 GEOLOGIC MAP OF FINAL GRADE WEST WALL OF DISCHARGE TUNNEL Revision 3606/29/23 MPS-3 FSAR 2.5.4-91

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-26 GEOLOGIC MAP OF FINAL GRADE EAST WALL OF DISCHARGE TUNNEL Revision 3606/29/23 MPS-3 FSAR 2.5.4-92

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-27 GEOLOGIC MAP OF FINAL GRADE DISCHARGE WEIR ROCK FACE Revision 3606/29/23 MPS-3 FSAR 2.5.4-93

Revision 3606/29/23 MPS-3 FSAR 2.5.4-94 FIGURE 2.5.4-28 CORRECTED BLOW COUNT PLOT, PUMPHOUSE AREA SANDS, ONSHORE BORING COMPOSITE

Revision 3606/29/23 MPS-3 FSAR 2.5.4-95 FIGURE 2.5.4-29 CORRECTED BLOW COUNT PLOT, PUMPHOUSE AREA SANDS, BORINGS P1 TO P8 COMPOSITE

M FIGURE 2.5.4-30 GRAIN SIZE DISTRIBUTION CURVES (SHEET 1)

Revision 3606/29/23 MPS-3 FSAR 2.5.4-96

FIGURE 2.5.4-30 GRAIN SIZE DISTRIBUTION CURVES (SHEET 2)

Revision 3606/29/23 MPS-3 FSAR 2.5.4-97

FIGURE 2.5.4-30 GRAIN SIZE DISTRIBUTION CURVES (SHEET 3)

Revision 3606/29/23 MPS-3 FSAR 2.5.4-98

FIGURE 2.5.4-30 GRAIN SIZE DISTRIBUTION CURVES (SHEET 4)

Revision 3606/29/23 MPS-3 FSAR 2.5.4-99

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-31 BORING LOCATION PLAN Revision 3606/29/23 MPS-3 FSAR 2.5.4-100

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-32 PLOT PLAN SHOWING LOCATIONS OF THE BORINGS AND THE GEOLOGIC SECTIONS Revision 3606/29/23 MPS-3 FSAR 2.5.4-101

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-33 GEOLOGIC PROFILE, SECTIONS A-A', B-B' Revision 3606/29/23 MPS-3 FSAR 2.5.4-102

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-34 GEOLOGIC PROFILE, SECTIONS C-C', D-D', E-E' Revision 3606/29/23 MPS-3 FSAR 2.5.4-103

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-35 GEOLOGIC PROFILE, SECTIONS F-F" AND G-G' Revision 3606/29/23 MPS-3 FSAR 2.5.4-104

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-36 TOP OF BASAL TILL CONTOUR MAP Revision 3606/29/23 MPS-3 FSAR 2.5.4-105

Revision 3606/29/23 MPS-3 FSAR 2.5.4-106 Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-37 GROUNDWATER CONTOUR MAP

Revision 3606/29/23 MPS-3 FSAR 2.5.4-107 FIGURE 2.5.4-38 GROUNDWATER OBSERVATIONS IN BOREHOLES

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-39 BEDROCK SURFACE CONTOUR MAP Revision 3606/29/23 MPS-3 FSAR 2.5.4-108

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-40 GENERAL EXCAVATION PLAN Revision 3606/29/23 MPS-3 FSAR 2.5.4-109

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-41 SHOREFRONT AND DREDGING PLAN Revision 3606/29/23 MPS-3 FSAR 2.5.4-110

Revision 3606/29/23 MPS-3 FSAR 2.5.4-111 FIGURE 2.5.4-42 MODULUS VS EFFECTIVE CONFINING PRESSURE, STRUCTURAL FILL

FIGURE 2.5.4-43 LATERAL PRESSURE DISTRIBUTION Revision 3606/29/23 MPS-3 FSAR 2.5.4-112

FIGURE 2.5.4-44 GRADATION CURVES FOR CATEGORY I STRUCTURAL FILL Revision 3606/29/23 MPS-3 FSAR 2.5.4-113

FIGURE 2.5.4-45 K2 VS SHEAR STRAIN FOR BEACH SANDS Revision 3606/29/23 MPS-3 FSAR 2.5.4-114

Revision 3606/29/23 MPS-3 FSAR 2.5.4-115 FIGURE 2.5.4-46 EARTHQUAKE INDUCED SHEAR STRESSES IN BEACH SANDS

Revision 3606/29/23 MPS-3 FSAR 2.5.4-116 FIGURE 2.5.4-47 CYCLIC STRESS RATIO VS CONFINING PRESSURE FOR BEACH SANDS

Revision 3606/29/23 MPS-3 FSAR 2.5.4-117 FIGURE 2.5.4-48 CYCLIC STRESS RATIO VS PENETRATION RESISTANCE OF SAND

Revision 3606/29/23 MPS-3 FSAR 2.5.4-118 FIGURE 2.5.4-49 FACTOR OF SAFETY AGAINST LIQUEFACTION OF BEACH SANDS

Revision 3606/29/23 MPS-3 FSAR 2.5.4-119 FIGURE 2.5.4-50 IDEALIZED SOIL PROFILE LIQUEFACTION ANALYSIS OF ABLATION TILL UNDER DISCHARGE TUNNEL

FIGURE 2.5.4-51 GEOLOGIC PROFILE, SECTION H-H

Revision 3606/29/23 MPS-3 FSAR 2.5.4-120

FIGURE 2.5.4-52 GEOLOGIC PROFILE, SECTION I-I

Revision 3606/29/23 MPS-3 FSAR 2.5.4-121

FIGURE 2.5.4-53 LOCATION OF FIELD DENSITY TESTS - SERVICE WATER INTAKE LINE Revision 3606/29/23 MPS-3 FSAR 2.5.4-122

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-54 LOCATION OF FIELD DENSITY TEST - EMERGENCY GENERATOR ENCLOSURE AND CONTROL BUILDING Revision 3606/29/23 MPS-3 FSAR 2.5.4-123

FIGURE 2.5.4-55 GEOLOGIC PROFILE, SECTION J-J' Revision 3606/29/23 MPS-3 FSAR 2.5.4-124

FIGURE 2.5.4-56 GEOLOGIC PROFILE, SECTION K-K' Revision 3606/29/23 MPS-3 FSAR 2.5.4-125

FIGURE 2.5.4-57 GRAIN SIZE DISTRIBUTION CURVES - PUMPHOUSE AREA OUTWASH SANDS (SHEET 1)

Revision 3606/29/23 MPS-3 FSAR 2.5.4-126

FIGURE 2.5.4-57 GRAIN SIZE DISTRIBUTION CURVES - PUMPHOUSE AREA OUTWASH SANDS (SHEET 2)

Revision 3606/29/23 MPS-3 FSAR 2.5.4-127

Revision 3606/29/23 MPS-3 FSAR 2.5.4-128 FIGURE 2.5.4-58 EQUIVALENT NUMBERS OF UNIFORM STRESS CYCLES BASED ON STRONGEST COMPONENTS OF GROUND MOTION

Withhold under 10 CFR 2.390 (d) (1)

FIGURE 2.5.4-59 PLAN OF SETTLEMENT MONITORING BENCHMARK LOCATIONS Revision 3606/29/23 MPS-3 FSAR 2.5.4-129

FIGURE 2.5.4-60 CONTROL BUILDING SETTLEMENT (SHEET 1)

Revision 3606/29/23 MPS-3 FSAR 2.5.4-130

FIGURE 2.5.4-60 CONTROL BUILDING SETTLEMENT (SHEET 2)

Revision 3606/29/23 MPS-3 FSAR 2.5.4-131

FIGURE 2.5.4-61 EMERGENCY GENERATOR ENCLOSURE SETTLEMENT Revision 3606/29/23 MPS-3 FSAR 2.5.4-132

FIGURE 2.5.4-62 .SOLID WASTE BUILDING SETTLEMENT Revision 3606/29/23 MPS-3 FSAR 2.5.4-133

FIGURE 2.5.4-63 LIQUID WASTE BUILDING SETTLEMENT Revision 3606/29/23 MPS-3 FSAR 2.5.4-134

FIGURE 2.5.4-64 FUEL BUILDING SETTLEMENT Revision 3606/29/23 MPS-3 FSAR 2.5.4-135

FIGURE 2.5.4-65 GEOLOGIC PROFILE SECTION L-L' Revision 3606/29/23 MPS-3 FSAR 2.5.4-136

FIGURE 2.5.4-66 GEOLOGIC PROFILE SECTION M-M' Revision 3606/29/23 MPS-3 FSAR 2.5.4-137

FIGURE 2.5.4-67 GEOLOGIC PROFILE SECTION N-N' Revision 3606/29/23 MPS-3 FSAR 2.5.4-138

FIGURE 2.5.4-68 GEOLOGIC PROFILE SECTION O-O' Revision 3606/29/23 MPS-3 FSAR 2.5.4-139

FIGURE 2.5.4-69 GEOLOGIC PROFILE SECTION P-P' Revision 3606/29/23 MPS-3 FSAR 2.5.4-140

FIGURE 2.5.4-70 GEOLOGIC PROFILE SECTION Q-Q' Revision 3606/29/23 MPS-3 FSAR 2.5.4-141

FIGURE 2.5.4-71 GEOLOGIC PROFILE SECTION R-R' Revision 3606/29/23 MPS-3 FSAR 2.5.4-142

Revision 3606/29/23 MPS-3 FSAR 2.5.4-143 FIGURE 2.5.4-72 SOIL-STRUCTURE INTERACTION EMERGENCY GENERATOR ENCLOSURE

Revision 3606/29/23 MPS-3 FSAR 2.5.4-144 FIGURE 2.5.4-73 SHEAR MODULUS CURVE TYPE 2 SOIL (STRUCTURAL BACKFILL AND BASAL TILL)

Revision 3606/29/23 MPS-3 FSAR 2.5.4-145 FIGURE 2.5.4-74 DAMPING CURVE TYPE 2 SOIL (STRUCTURAL BACKFILL AND BASAL TILL)

FIGURE 2.5.4-75 SHOREFRONT PROFILE USED IN LIQUEFACTION ANALYSES Revision 3606/29/23 MPS-3 FSAR 2.5.4-146

topography in the plant area is generally flat with the final grade at el +24 feet in the major t area. Detailed analyses were performed to determine static and dynamic stability of two

-made slopes at the site. The beach and outwash sand and armor stone slope at the shoreline, cent to the pumphouse, was analyzed using circular failure surfaces according to methods eloped by Bishop (1955) and incorporated in the LEASE II (SWEC 1977) computer program.

analysis showed that the slope (Figure 2.5.5-1) was safe under an average amplified seismic ing of 0.25g and under static conditions.

vertical rock cut excavated for the containment structure, (Figure 2.5.5-2) was analyzed by ming failure planes developed along fully continuous joint and foliation surfaces. Methods eloped by Hendron et al. (1971) and incorporated into the computer program SWARS-2P EC 1974b) were used to analyze slope stability of this rock cut under both static and dynamic ing conditions. It was determined that the stability of these slopes was inadequate to maintain ation of the containment structure walls from the external load applied by the rock wedges. As sult, a continuous structural hoop or ring beam was constructed in the annular space between containment walls and the rock face. The purpose of this ring beam is to transfer any rock ing from the less stable areas where potential failure wedges may form to the more stable s elsewhere around the containment, maintaining isolation of the rock loads from the tainment exterior walls. Section 3.8.1.1 discusses the details of the ring beam design.

5.1 SLOPE CHARACTERISTICS 5.1.1 Shoreline Slope lan of the shoreline in the vicinity of the Millstone 3 pumphouse is shown on Figure 2.5.4-41.

he east of the pumphouse, a reinforced concrete seawall with post-tensioned rock anchors has n built between the pumphouse and the Millstone 2 intake structure to retain the earth and ect the structures from wave action. On the west side of the pumphouse, extending in a herly direction, is a reinforced concrete retaining wall keyed into rock. The purpose of this l is to protect the circulating and service water lines from being undermined due to wave on on the adjoining slope. To the west of the pumphouse, a variable slope has been cut in the ch and outwash sand to provide for a transition from the offshore intake channel at el -32 feet he pumphouse area site grade at el +14 feet. The slope varies from five horizontal to one ical immediately adjacent to the pumphouse, to ten horizontal to one vertical near Bay Point, western extent of the beach. Compacted backfill was placed in areas where additional fill was uired to meet these grade requirements.

ultilayer stone armor zone was placed on the slope for protection against wave action during probable maximum hurricane. The maximum significant wave height of 13 feet was used to gn the slope protection system. The techniques used are described in the U.S. Army Shore tection Manual (USA CERC 1975).

armor layer is designed as a 2-layer system. The weight of stone was obtained from the ation:

W = ---------------------------------------------

3 K D S r - 1 cot re:

Wr = unit weight of the stone = 160 pcf H = design wave height = 13 ft Sr = specific gravity of rock with respect to seawater = 2.5 q = angle of slope = 5:1 = 11.3 KD = stability coefficient = 3.5 (assuming 2 layers of randomly placed rough angular quarrystone, a breaking wave, and a structure trunk with 0 to 5 percent armor layer damage).

individual stone weight of 6,000 pounds was obtained for the primary armor stone cover layer.

ange of 0.75W to 1.25W was allowed in specifications. Stone sizes, based on cubic shapes, ged from 3.0 to 3.6 feet.

thickness of the 2 armor layers was calculated as 7.7 feet. A minimum still water level of ation -3 feet was assumed in calculating the bottom of the primary armor layer at elevation feet. A secondary rock protection layer, referred to as Type B material, was calculated to be pound stone. Two layers of secondary protection, varying in size from 300 pounds to 700 nds with 75 percent greater than 500 pounds, with a minimum thickness of 3.6 feet, were rmined as necessary underlayment for the primary armor stone layer. This secondary layer placed on a continuous filter fabric layer.

in situ beach sands and compacted fill layers are overlain by filter fabric, which prevents ration of finer materials into the rock protection layers. Figure 2.5.5-1 shows a detailed cross-ion of the slope protection system. Stone for the slope protection was obtained from bedrock viously blasted during excavation at the site and from offsite sources.

ings P1 through P10 and I1 through I12 were drilled onshore in the vicinity of the pumphouse.

P-series of borings included undisturbed sampling of the saturated beach sands using the erberg sampler. The location of these borings is shown on Figure 2.5.4-31. A geologic profile ss this area is shown on Figure 2.5.4-35. The depth of sand along the beach varies from zero ay Point and the area just west of the Millstone 2 intake structure, where exposed rock is ent, to a maximum of approximately 40 feet in the vicinity of the Millstone 3 pumphouse.

beach and outwash sand deposits overlie a thin layer of basal till, generally less than 5 feet k which covers the bedrock. The relative density of the beach sand determined from the bs-Holtz correlation of blow count data averages approximately 70 percent. The data points plotted on Figure 2.5.4-28. No extensive or continuous loose zones were detected in these ngs.

reactor containment building is founded on bedrock at approximately el -39 feet. Top of rock es from approximately el 0 feet to el 20 feet, as shown on the bedrock surface contour map ure 2.5.4-39). The excavation walls are vertical, with a 9-inch bench at el -17 feet. The avation of bedrock for the containment is described in detail in Section 2.5.4.5.1.

a result of detailed geologic mapping of the bedrock surface during construction, described in tion 2.5.4.1.1, additional preferred joint sets were noted beyond those previously reported in local geological literature (Goldsmith 1967). These joint sets have been interpreted from the eonet projection plots for top of bedrock mapping previously reported (NNECo. 1975) and ted from final excavation grade data on Figure 2.5.1-16. Cross sections through the critical ges are shown on Figure 2.5.5-2.

assumption that failure surfaces develop in the bedrock along joint and foliation surfaces is y conservative. For this to occur, joint and foliation surfaces must be at least as long as the zontal projection of the wedge failure surfaces and must extend from the rock surface to a imum elevation of -27 feet, which corresponds to the top of the containment mat. There is no evidence that this situation does occur around the containment structure, particularly with ect to the minor joint sets. However, for the purposes of analysis, the joint and foliation planes modeled as flat, smooth continuous surfaces.

ect shear tests were conducted on samples of both foliation and joints to determine the tional values for each plane. A direct shear device capable of developing the low normal es representative of field conditions and sensitive enough to measure the shear force was used est NX core samples of rock from the borings previously taken in the vicinity of the tainment structure. A description of the samples tested is shown in Table 1 of Appendix 2.5I.

peak and residual values are plotted on Figure 2 of Appendix 2.5I. For analysis, a friction le of 32 degrees was used for the foliation, equals 34 degrees for the predominant joint set 04E and equals 37 degrees for the minor joint sets. These values do not take into account added strength of the asperities, which was significant for the higher normal stresses.

5.2 DESIGN CRITERIA AND ANALYSIS 5.2.1 Shoreline Slope omputer program, LEASE II (Limiting Equilibrium Analysis of Slopes and Embankments)

EC 1977), was used to analyze the stability of the shoreline slope. This program, part of ICES egrated Civil Engineering System--VI M3, dated November 1969), is accepted and widely d by soil mechanics and foundation engineers for analyzing slope stability problems. This ion is an update of an earlier version and provides for making dynamic analyses. LEASE II is ently being run on an IBM-370 Operating System, Model 165 at the SWEC Computer Center.

ASE II calculates three different factors of safety. The methods of analysis include the plified Bishop method of slices, the Fellenius method of slices, and the Rankine wedge hod. The simplified Bishop method of analysis was used to compute factors of safety of the

itman and Bailey indicate that the error involved in the simplified Bishop method is usually than 5 percent and, therefore, recommend it be used for slope stability analyses.

shoreline slope shown on Figure 2.5.4-41 was analyzed for static, dynamic, and post-hquake conditions. The slope to the west of the circulation and service water pumphouse is l-shaped. It is 5H to 1V at the steepest portion and decreases to 10H to 1V adjacent to the ke channel. Conservative assumptions were made in constructing the analytical model for the e stability analysis. The end constraints of three dimensional geometry were ignored and the re slope was assumed to be 5H:1V. A section through the modeled slope together with a mary of the results of the slope stability analysis is presented on Figure 2.5.5-1. Factors of ty are defined as the available shear resistance along a postulated failure surface divided by maximum driving forces along that surface.

ure 2.5.4-37 shows a groundwater gradient from the main plant area toward Long Island nd. Groundwater levels in boring 316, which is approximately 250 feet from the pumphouse, ed between elevations 6.4 and 8 feet. Water levels of elevation +6 feet onshore and -6 feet hore were conservatively selected to maximize the destabilizing forces in the analysis. These ls represent approximately four times the normal tidal range, and elevation +6 feet esponds to an appropriate flood tide level at the site.

strength properties used in the stability analysis were selected on the basis of standard etration tests and of cyclic triaxial and consolidated undrained (CIU) triaxial tests on isturbed samples, as reported in Appendixes 2.5G and 2.5F, respectively. The effect of sible pore pressure buildup in the beach and outwash sands was accounted for in the stability lysis for the post-earthquake conditions.

tatic slope stability analysis was conducted using the assumptions described above together h strengths for the various slope materials as shown on Figure 2.5.5-1. The effective internal tion angles assigned to the beach and glacial outwash sand were selected on the basis of dard penetration tests and of the CIU triaxial tests on undisturbed samples. The CIU tests (see endix 2.5G and Figure 2.5.5-5) revealed effective internal friction angles of 33 to more than degrees for the samples tested. For internal friction, an angle of 34 degrees was used in the lysis. The minimum factor of safety against slope failure for the static case is 2.9, which is quate. The dynamic slope stability during the SSE was evaluated by using a pseudo-static roach and undrained shear strengths of the soils. Input horizontal and vertical accelerations of 5g and 0.17g were based on the average amplified accelerations described in tions 2.5.4.8.3.1 and 2.5.4.9. Acceleration directions were selected to maximize instability.

rained strength parameters for the beach and glacial outwash sands were derived based on rained triaxial compression test results reported in Appendix 2.5G. Stress paths and data from e tests indicate that during undrained loading the average A parameter at maximum obliquity 0.13. The values of A ranged from +0.33 to -0.16. An A parameter equal to 0.5 and an rnal friction angle of 34 were used to derive the undrained strengths of the beach and glacial wash sands. These values are considered to be conservative based on the in situ density and

l of each layer.

ults of the pseudo-dynamic stability analysis indicate that the minimum factor of safety inst slope failure is 0.9 for the assumed conditions. This result is very conservative because of assumptions made about slope geometry and end effects. An additional analysis was ormed on this slope considering only the horizontal component of seismic loading, and a ty factor of 1.16 was calculated for the same failure circle.

to the low factor of safety obtained, an analysis was performed to estimate the deformations ch could theoretically occur along the postulated failure surface during earthquake loading.

analysis is based on an approach presented by Newmark (1965) using the computer program ES (Seismically Induced Displacement of Embankments and Slopes, SWEC, 1979) which ulates the cumulative mono-directional sliding displacement of a rigid body shaken by an hquake. An input earthquake accelerogram is represented by a maximum 12,000 point time ory of acceleration. No motion is assumed to occur within the slope until the strength of the is exceeded; i.e., the limiting acceleration producing a safety factor of 1.0 is exceeded.

lytical equations governing rigid solution are then solved incrementally on the assumption the input acceleration varies linearly from point to point, and that the displacements are ulative throughout the duration of the earthquake. Each of the three earthquakes used to pute the dynamic response of the soil were used (Section 2.5.4.8.3). Their time histories were ed to the appropriate average amplified accelerations (i.e., vertical acceleration of 0.17g and zontal acceleration of 0.25g) described above. Results from each of these earthquakes cate maximum cumulative slope movements less than 0.1 inch. The limiting horizontal and ical acceleration used were 0.2g and 0.12g, respectively. These results indicate that if there is movement of the slope during the SSE, the movement would be negligible. There would be dverse effect to any safety related system component or structures.

ost-earthquake stability analysis was performed to quantify the effect of pore pressure erated by the earthquake. The magnitude of pore pressure buildup was estimated from results yclic triaxial tests (Appendix 2.5F) considering such factors as the number of equivalent les, cyclic shear stress levels, confining pressures, material density, and gradation. The pore sure buildup for 5 cycles of loading on samples which most closely represent the in situ dition and dynamic loading was between 40 and 60 percent of the effective confining sure. An estimated pore pressure buildup of 50 percent was used to evaluate the post-hquake slope stability. Therefore, the soil properties are the same as in the static case but the e pressures are increased during the LEASE analysis. Results of the post-earthquake analyses al that the minimum factor of safety against slope failure is 1.4. This is considered acceptable.

analysis of slope stability indicates that the shoreline slope is stable under static, dynamic, post-earthquake conditions.

ddition to the above analysis, where the shorefront slope was considered to consist of a orm deposit of outwash sand to el -40 feet, the actual subsurface conditions were modeled to rmine whether a more critical cross-section existed due to sloping bedrock conditions at the refront. The actual soil profiled in this area is shown on Figure 2.5.4-52. This condition was

sloping rock condition used in the slope stability analysis showing soil properties and slope metry is shown on Figure 2.5.5-4.

minimum safety factor for static loading conditions is 3.2 for a circular arc failure surface.

s compares to a safety factor of 2.9 for the circular failure surface in the analysis for a uniform th of sand to el -40 feet indicating that the sloping rock profile is less critical than the uniform d profile. Also, the dynamic analysis for the sloping rock profile is less critical than the orm sand profile because the magnitude of the dynamic forces is reduced due to less lification through the stiffer till and because of the shallower depth to bedrock. The minimum ty factor for dynamic loading conditions is comparable with the uniform sand profile when ilar dynamic forces are assumed.

rgenstern-Price wedge failure analyses were also performed to further investigate the sloping k profile. Safety factors for static loading conditions of 4.14 for shallow wedge and 3.54 for per wedge failure surfaces were calculated. These safety factors against slope failure are her than the circular arc safety factor of 3.2 and confirm the inherent conservatism of the ular arc failure analysis.

uefaction of the shoreline slopes was also investigated. The analyses (Section 2.5.4.8.3) show the beach sands would not liquefy when subjected to the SSE.

5.2.2 Containment Rock Cut o computer programs have been developed to evaluate field data and compute the stability of k slopes. JTPLOT(ST-212) (SWEC 1974a) is used to reduce data from joint and foliation eys and to prepare contoured stereographic plots, such as those on Figures 2.5.1-15 and 1-16. SWARS-2P (SWEC 1974b) is used to analyze the stability of tetrahedral rock wedges med by the intersections of joint and foliations surfaces with the vertical excavation face. The are input in geological notation and are converted internally to the format required for rock hanics calculations. All possible combinations of joints are automatically considered. Effects eismic loads, rock bolts, surcharges, point loads, and several types of piezometric loads are uded in the analysis. In designing a restraining hoop or ring beam, the forces required to ilize the sliding wedges are input into the program as hypothetical rock bolts, with the load ributed across the projected vertical area of the rock wedge. A minimum safety factor of 1.1 considered acceptable for determining required stabilizing forces.

he analysis, the surcharge loading from adjacent structures was accelerated in the vertical ction, and soil surcharge was accelerated both vertically and horizontally. Water pressure was applied to the rock wedge surfaces, on the assumption that the differential head acts directly he containment wall. However, the buoyant weight of the rock was used to account for the ence of groundwater. This assumption is considered conservative because the buoyant weight ctively reduces the resistive forces. Wedges smaller than 100 cubic feet were disregarded, on assumption that these wedges were formed by the intersection of two high angle joint sets, and e probably removed during blasting and scaling operations.

ibit a high density of fractures that could produce these wedges. Figure 2.5.5-7 is a tograph showing the rock surface commonly found in the area of the main steam valve ding.

forces applied by the rock wedges on the ring beam are shown on Figure 2.5.5-3. The imum forces act in the southwest quadrant, due to the effect of the weaker foliation planes ch dip into the excavation face in this area. Other areas of instability can be attributed to the h dip angles of the jointing, which are inherently unstable when subjected to seismic and harge loadings. The design of the structural support, or ring beam, which transfers this load und the excavation, maintaining the isolation of containment structure from these external s, is discussed in detail in Section 3.8.1.1.

5.3 LOGS OF BORINGS boring logs are included in Appendix 2.5J. No borings were taken in borrow areas for erials used onsite.

5.4 COMPACTED FILL ctural backfill used to raise the shoreline slopes to final design lines meets the requirements ined in Section 2.5.4.5.2.

5.5 REFERENCES

FOR SECTION 2.5.5 5.1-1 Bishop, A.W., 1955. The use of the Slip Circle in the Stability Analysis of Slopes.

Geotechnical, Vol V.

5.1-2 Goldsmith, R. 1967. Bedrock Geologic Map of Niantic Quadrangle, Penn. U.S.

Geological Survey Quadrangle Map GQ-575, Washington, D.C.

5.1-3 Hendron, A.J.; Cording, E.J.; Aiyer, A.K., 1971. Analytical and Graphical Methods for the Analysis of Slopes in Rock Masses. NCG Technical Report No. 36.

5.1-4 Northeast Nuclear Energy Co. (NNECo.), 1975. Geologic Mapping of Bedrock Surface. Millstone Nuclear Power Station - Unit 3, Docket No. 50-423.

5.1-5 Stone & Webster Engineering Corporation (SWEC), 1974a. Stereographic Projection of Joints (JTPLOT). Computer Program ST-212. SWEC, Boston, Mass.

5.1-6 Stone & Webster Engineering Corporation (SWEC), 1974b. Analytical Method for Analysis of Stability of Rock Slopes; SWARS-2P. Computer Program ST-214.

SWEC, Boston, Mass.

Boston, Mass.

5.1-8 Stone & Webster Engineering Corporation (SWEC), 1979. Seismically Induced Displacements of Embankments and Slopes, Sides. Computer Program GT-009.

SWEC, Boston, Mass.

5.1-9 U.S. Army Coastal Engineering Research Center, 1975. Shore Protection Manual.

Department of the Army, Corps of Engineers, Washington, D.C. Vol II, Ch. 7.

5.1-10 Whitman, R.V. and Bailey, W.A., 1967. Use of Computers for Slope Stability Analyses. Journal of Soil Mechanics and Foundations Division, ASCE. Vol 93, SM4.

5.1-11 Whitman, R.V. and Moore, P.J., 1963. Thoughts Concerning the Mechanics of Slope Stability Analyses. Proceedings, Second Pan American Conference on Soil Mechanics and Foundation Engineering.

EXCAVATION BUILDING embankments or dams have been constructed at the Millstone site.

APPENDIX 2.5A- AGE OF TILL AT MILLSTONE POINT D.W. Caldwell, PhD

D. W. Caldwell, Ph.d.

Till at Millstone Point till exposures at Millstone are inadequate for the purpose of establishing their time of osition. The best exposures exist along an embankment some 200 feet long and from 10 to 15 high just to the west of the switchyard northeast of the plant. Part of this exposure has about 5 of artificial fill, covered by six inches of concrete. Beneath the fill, a grey, compact, clay -

h till is exposed. This till has few large stones and the matrix is closely jointed. At the northern of the embankment, the till is less compact and less jointed. The complete exposure is equate to determine the relationship between the two exposures of till, that is, whether one till nitely underlies the other or whether a single till simply changes in its texture and pactness from one exposure to another.

ause of the rarity of two-till exposures in New England, it is most probable that a single body ill, changing in its physical character from one place to the next, exists at the Millstone site. A ll likelihood exists that there are two separate bodies of till at Millstone, a fact which can only stablished by further and more extensive excavation.

Two-till Problem in New England several localities in southern New England there is evidence of two tills, believed to be of erent ages (Schafer and Hartshorn, 1965; Pessl and Schafer, 1968). The older till is usually pact, contains much silt and clay and has closely spaced jointing. Oxidation in the older till ges to depths of 10 or more feet. Drumlins are generally composed of the older till.

younger till is generally less compact, is sandier and does not contain numerous joints or ated structures. Oxidation is less than 3 feet and is usually absent altogether.

Age of Older Till hree localities in New England organic material beneath the lower till has been dated. At New ron, Maine, wood embedded in weathered sand, lying between two tills, has a radiocarbon age more than 44,000 years B.P. (W-910; Caldwell, 1959). Wood at the base of an exposure of till allingford, Connecticut, has been dated as more than 40,000 years B.P. (Y-451). Peat overlain rumlin sediments in Worcester, Massachusetts, has been dated as more than 38,000 years B.P.

647, L-380). All of these listed C-14 ages of the older till are (or were at the time of analysis) ond the range of carbon-14 analysis, although they are probably post-Sangamon in age, that is, than about 100,000 years old. Without deposits of organic material at other till localities in w England, it is not possible to relate them to these three till sites where dating has been sible.

emplacement of the younger till is more firmly established than that of the older till, but her has been dated as completely and as consistently as they have been in the mid-west.

last (Wisconsin) ice sheet covered all of New England and its terminal position is marked by moraines on Long Island (Ronkonkoma moraine) and the Islands (Nantucket moraine on thas Vineyard and Nantucket). The advance of this ice sheet is dated by organic material, r than the advance, incorporated in till at Harvard, Massachusetts (21,200 1,000 years B.P.;

44), and shells in drift on outer Cape Cod (20,700 2,000 years B.P.). On Marthas Vineyard t material in clay (15,300 800 years B.P.; W-1187) is overlain by till from a slight readvance he ice margin.

Marthas Vineyard moraine can be traced by underwater topography to Block Island and to g Island and the Ronkonkoma moraine, about 50 miles south of Millstone Point. The chart

. 1) presents the spatial and temporal relationship of the advance of the Wisconsin ice over the lstone area about 18,000 years ago. This is the approximate age of the upper part of the till at lstone (assuming there are two tills) or all the till (assuming there is but one till).

retreat of the Wisconsin ice from its terminus at the Ronkonkoma - Block Island moraine is d by numerous C-14 ages of organic material overlying the upper till. At Rogers Lake, Lyme, necticut, basal peat overlying last till is 14,240 240 years B.P. (Y-950/51). Other dates of ilar material in Connecticut and Massachusetts are consistent with the Rogers Lake date.

t (1953, 1958) describes a short readvance of the ice to Middletown, Connecticut, before, but bably not long before, about 13,000 years ago. Following this readvance the ice melted dly up the Connecticut River Valley and Glacial Lake Hitchcock was formed in the valley by ck dam at Rocky Hill, Connecticut, north of Middletown. This lake was drained between 10 and 10,650 years B.P. (Y-253 and Y-251; Flint, 1956).

Conclusions last till deposition at Millstone Point occurred about 18,000 years ago. The area remained

- covered until about 14,000 years ago. If older till exists at Millstone, it may be equivalent to pre-Wisconsin-post-Sangamon till deposited more than 40,000 years ago. A more complete osure of the Millstone till would be required in order to establish the presence or absence of tills at the site.

erences for Appendix 2.5A A-1 Caldwell, D.W. 1959. Glacial Lake and Glacial Marine in the Farmington Area, Main.

Main Geological Survey Spec. Geol. Stud. 3.

A-2 Flint, R.F. 1953. Probable Wisconsin Substages and late Wisconsin Events in Northeastern United States. G.S.A. Bul. V 64, p 897-919.

A-4 Two Tills in Southern Connecticut. 1958. G.S.A. Bul. V 72, p 1687-1692.

A-5 Schafer, P. and Pessl, F. 1968. Two-till Problem in Naugatuck-Torrington Area, Western Connecticut. New England Intercol. Geol. Conf. Guidebook.

A-6 Schafer, P. and Hartshorn, J. 1965. The Quaternary of New England. In: The Quaternary of the United States, Wright, H.E. (Ed) Princeton Univ. Press.

CLICK HERE TO SEE APPENDIX 2.5B CLICK HERE TO SEE APPENDIX 2.5C CLICK HERE TO SEE APPENDIX 2.5D CLICK HERE TO SEE APPENDIX 2.5E CLICK HERE TO SEE APPENDIX 2.5F CLICK HERE TO SEE APPENDIX 2.5G CLICK HERE TO SEE APPENDIX 2.5H CLICK HERE TO SEE APPENDIX 2.5I CLICK HERE TO SEE APPENDIX 2.5J CLICK HERE TO SEE APPENDIX 2.5K CLICK HERE TO SEE APPENDIX 2.5L CLICK HERE TO SEE APPENDIX 2.5M