Text

2 to Updated Final Safety Analysis Report, Chapter 2, Site Characteristics - (EPID L-2020-LRO-0076) - Redacted
	ML21208A418
Person / Time
Site:	Surry
Issue date:	09/30/2020
From:	; Virginia Electric & Power Co (VEPCO)
To:	; Office of Nuclear Reactor Regulation
	Thomas V
Shared Package
ML21208A006	List: ML21208A367; ML21208A409; ML21208A418; ML21208A424; ML21208A429; ML21210A125; ML21210A126; ML21210A127; ML21210A128; ML21210A129; ML21210A133; ML21210A135; ML21210A136; ML21210A137; ML21210A138; ML21210A139; ML21210A140;
References
	20-325, EPID L-2020-LRO-0076
	Download: ML21208A418 (216)
	v • d • e

Surry Power Station Updated Final Safety Analysis Report Chapter 2

Intentionally Blank Revision 52Updated Online 09/30/20 SPS UFSAR 2-i Chapter 2: Site Characteristics Table of Contents Section Title Page 2.1 GEOGRAPHY, DEMOGRAPHY AND POTENTIAL EXTERNAL HAZARDS 2.1-1 2.1.1 Site Location and Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-1 2.1.1.1 Site Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-1 2.1.1.2 Site Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-2 2.1.1.3 Boundaries for Establishing Effluent Release Limits . . . . . . . . . . . . . . . . . . . 2.1-2 2.1.2 Exclusion Area Authority and Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-3 2.1.2.1 Authority . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-3 2.1.2.2 Control of Activities Unrelated to Plant Operation . . . . . . . . . . . . . . . . . . . . . 2.1-3 2.1.2.3 Arrangements for Traffic Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-3 2.1.3 Population Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-3 2.1.3.1 Population Within 10 Miles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-3 2.1.3.2 Population Between 10 and 50 Miles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-4 2.1.3.3 Transient Population . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-4 2.1.3.4 Low Population Zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-5 2.1.3.5 Population Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-5 2.1.3.6 Population Density . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-6 2.1.4 Nearby Industrial, Transportation, and Military Facilities . . . . . . . . . . . . . . . . . 2.1-6 2.1.4.1 Location and Routes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-6 2.1.4.2 Description of Facilities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-6 2.1.4.3 Pipelines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-7 2.1.4.4 Waterways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-7 2.1.4.5 Roads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-8 2.1.4.6 Airports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-8 2.1.4.7 Projections of Facility Growth. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-9 2.1.5 Evaluation of Potential Accidents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-9 2.1.5.1 Explosions and Flammable Vapor Clouds . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-9 2.1.5.2 Toxic Chemicals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-11 2.1.5.3 Aircraft Accidents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-11 2.1 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-12 2.1 Reference Drawings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-14 2.2 METEOROLOGY AND CLIMATOLOGY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2-1 2.2.1 Meteorological Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2-1 2.2.1.1 Local Meteorology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2-1 2.2.1.2 Onsite Meteorological Measurements Program . . . . . . . . . . . . . . . . . . . . . . . 2.2-2

Revision 52Updated Online 09/30/20 SPS UFSAR 2-ii Chapter 2: Site Characteristics Table of Contents (continued)

Section Title Page 2.2.2 Climate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2-4 2.2.2.1 Tornadoes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2-5 2.2.2.2 Extreme Winds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2-7 2.2.2.3 Tropical Storms and Hurricanes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2-7 2.2 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2-8 2.3 HYDROLOGY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3-1 2.3.1 Surface Water Hydrology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3-1 2.3.1.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3-1 2.3.1.2 Floods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3-3 2.3.2 Ground-Water Hydrology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3-9 2.3 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3-11 2.3 Reference Drawings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3-12 2.4 GEOLOGY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-1 2.4.1 Geologic Investigations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-1 2.4.2 GeologySummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-3 2.4.2.1 Basic Geology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-3 2.4.2.2 Geologic History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-5 2.4.2.3 Structural Geology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-7 2.4.3 Soil Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-8 2.4.3.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-8 2.4.3.2 Pleistocene Clays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-8 2.4.3.3 Pleistocene Sands. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-8 2.4.3.4 Miocene Deposits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-11 2.4.3.5 Site Settlement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-11 2.4.4 Ground-Water Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-11 2.4.5 Liquefaction Potential . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-14 2.4.5.1 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-14 2.4.5.2 Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-15 2.4.6 Piling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-17 2.4.7 Foundation Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-18 2.4.7.1 Reactor Containment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-18 2.4.7.2 Spent-Fuel Building. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-20 2.4.7.3 Auxiliary Building and Control Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-20

Revision 52Updated Online 09/30/20 SPS UFSAR 2-iii Chapter 2: Site Characteristics Table of Contents (continued)

Section Title Page 2.4.7.4 Turbine Room . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-20 2.4.7.5 Miscellaneous Yard Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-20 2.4.7.6 Screen Well . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-20 2.4.8 Relative Earthquake Displacements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-21 2.4.9 Slope and Bank Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-23 2.4 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-26 2.5 SEISMOLOGY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5-1 2.5.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5-1 2.5.2 Tectonics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5-1 2.5.3 Seismicity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5-4 2.5.3.1 Earthquake History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5-4 2.5.3.2 Correlation of Epicenters with Geologic Structures . . . . . . . . . . . . . . . . . . . . 2.5-5 2.5.3.3 Identification of Active Faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5-7 2.5.4 Seismic Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5-7 2.5.4.1 Operating-Basis Earthquake (OBE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5-7 2.5.4.2 Design-Basis Earthquake (DBE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5-8 2.5.4.3 Seismicity Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5-9 2.5.5 Estimated Ground Acceleration for Design-Basis Earthquake . . . . . . . . . . . . . . 2.5-10 2.5.5.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5-10 2.5.5.2 Amplification Spectrum. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5-10 2.5.5.3 Available Strong Motion Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5-12 2.5.5.4 Theoretical Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5-13 2.5.5.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5-13 2.5.6 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5-13 2.5 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5-14

Revision 52Updated Online 09/30/20 SPS UFSAR 2-iv Chapter 2: Site Characteristics List of Tables Table Title Page Table 2.1-1 Major Military, Commercial and Industrial Facilities . . . . . . . . . . . . . . 2.1-15 Table 2.1-2 Tourist Attractions, Parks and Recreational Areas . . . . . . . . . . . . . . . . 2.1-16 Table 2.1-3 Airports Within 20 Miles of the Site . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-18 Table 2.1-4 Surry Onsite Chemicals (Largest Individual Container) . . . . . . . . . . . . 2.1-19 Table 2.2-1 Selected National Weather Service Stations for Meteorological Extremes in the Surry Site Region (Date of Occurrence) . . . . . . . . . . . 2.2-10 Table 2.2-2 Normals, Means, and Extremes - Richmond, Virginia . . . . . . . . . . . . . 2.2-11 Table 2.2-3 Normals, Means, and Extremes - Norfolk, Virginia . . . . . . . . . . . . . . . 2.2-13 Table 2.2-4 Monthly Meteorological Means for Temperature and Precipitation for Stations in the Surry Site Region . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2-15 Table 2.2-5 Surry Seasonal and Annual Mean Wind Speed Summary (MPH) 1974 - 1987 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2-16 Table 2.2-6 Horizontal (sq) Stability Categories . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2-16 Table 2.2-7 Vertical (T) Stability Categories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2-17 Table 2.2-8 Primary met tower instrument heights (agl)* . . . . . . . . . . . . . . . . . . . . 2.2-17 Table 2.2-9 Surry Seasonal and Annual Stability and Wind Speed Distribution 1974 - 1987 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2-18 Table 2.2-10 Meteorological Information Display Locations . . . . . . . . . . . . . . . . . . . 2.2-19 Table 2.3-1 Mean Monthly Discharge in CFS - James River at Station Site for Water Years 1935 through 1993 (i.e., October 1934 through September 1993) . . . . . . . . . . . . . . . . . . . . 2.3-13 Table 2.3-2 Duration Data Monthly Mean Discharge - Fresh Water James River at Surry Power Station (1935-1993) . . . . . . . . . . . . . . . . . 2.3-17 Table 2.3-3 Magnitude and Frequency of Flood Discharges on the James River Near Richmond, Virginia (For the Period of Record 1935 - 1993) . . . . . . . . 2.3-17 Table 2.3-4 Magnitude and Frequency of Flood Discharges at Station Site. . . . . . . 2.3-18 Table 2.3-5 Estimated Tidal Recurrence Interval at Old Point Comfort. . . . . . . . . . 2.3-18 Table 2.3-6 Components of Highest Stillwater Level (Open Coast) for the Probable Maximum Hurricane . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3-19 Table 2.3-7 Maximum-Probable-Flood Protection Levels for Class I Structures. . . 2.3-20 Table 2.4-1 Orogenic Movements in the Central Appalachian Region . . . . . . . . . . 2.4-28 Table 2.4-2 Density Data for Sand Members, from Onsite Tests in Cofferdam. . . . 2.4-29

Revision 52Updated Online 09/30/20 SPS UFSAR 2-v Chapter 2: Site Characteristics List of Tables (continued)

Table Title Page Table 2.4-3 Grain Size Analysis, Sand B, Cofferdam No. 1. . . . . . . . . . . . . . . . . . . 2.4-32 Table 2.4-4 Penetration Resistance from Borings, Sand A (Upper Sand) . . . . . . . . 2.4-33 Table 2.4-5 Penetration Resistance From Borings, Sand B (Lower Sand) . . . . . . . . 2.4-36 Table 2.4-6 Differential Movement (ft). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-39 Table 2.4-7 Piezometer Comparison Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-40 Table 2.4-8 Computed Ground Motion And Intensity, Liquefaction Analysis. . . . . 2.4-40 Table 2.4-9 Modal Dynamic Analysis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-40 Table 2.4-10 Shear Stress Value for Yard Area, Liquefaction Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-41 Table 2.4-11 Allowable Pile Holdings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-41 Table 2.4-12 Foundation Types. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-41 Table 2.4-13 Displacements Under Earthquakea . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-42 Table 2.4-14 Computed Deflections For Concrete-filled Pipe Pilings . . . . . . . . . . . . 2.4-44 Table 2.5-1 Modified Mercalli Intensity (Damage) Scale of 1931 (Abridged) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5-16 Table 2.5-2 Significant Earthquakes of All Earthquakes Within 50 Miles of Site and All Earthquakes of Intensity V or Greater Within 200 Miles of Siteb . . 2.5-17 Table 2.5-3 Earthquake Cycles of Significant Motion . . . . . . . . . . . . . . . . . . . . . . . 2.5-25

Revision 52Updated Online 09/30/20 SPS UFSAR 2-vi Chapter 2: Site Characteristics List of Figures Figure Title Page Figure 2.1-1 Ten Mile Surrounding Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-20 Figure 2.1-2 Fifty Mile Surrounding Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-21 Figure 2.1-3 Site Boundary and Major Structures . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-22 Figure 2.1-4 Site Boundary and Unrestricted Areas. . . . . . . . . . . . . . . . . . . . . . . . . 2.1-23 Figure 2.1-5 10 Mile Population Distribution- 1990 . . . . . . . . . . . . . . . . . . . . . . . . 2.1-24 Figure 2.1-6 10 Mile Population Distribution - 2000 . . . . . . . . . . . . . . . . . . . . . . . . 2.1-25 Figure 2.1-7 10 Mile Population Distribution - 2010 . . . . . . . . . . . . . . . . . . . . . . . . 2.1-26 Figure 2.1-8 10 Mile Population Distribution - 2020 . . . . . . . . . . . . . . . . . . . . . . . . 2.1-27 Figure 2.1-9 10 Mile Population Distribution - 2030 . . . . . . . . . . . . . . . . . . . . . . . . 2.1-28 Figure 2.1-10 50 Mile Population Distribution - 1990 . . . . . . . . . . . . . . . . . . . . . . . . 2.1-29 Figure 2.1-11 50 Mile Population Distribution - 2000 . . . . . . . . . . . . . . . . . . . . . . . . 2.1-30 Figure 2.1-12 50 Mile Population Distribution - 2010 . . . . . . . . . . . . . . . . . . . . . . . . 2.1-31 Figure 2.1-13 50 Mile Population Distribution - 2020 . . . . . . . . . . . . . . . . . . . . . . . . 2.1-32 Figure 2.1-14 50 Mile Population Distribution - 2030 . . . . . . . . . . . . . . . . . . . . . . . . 2.1-33 Figure 2.1-15 Population Density. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-34 Figure 2.1-16 Adjacent Pipelines and Waterways . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-35 Figure 2.1-17 Location of Airports. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1-36 Figure 2.2-1 Surry Seasonal Wind Direction Roses Low Level Winds 1974 - 1987 Season = Spring . . . . . . . . . . . . . . . . . 2.2-20 Figure 2.2-2 Surry Seasonal Wind Direction Roses Low Level Winds 1974 - 1987 Season = Summer . . . . . . . . . . . . . . . 2.2-21 Figure 2.2-3 Surry Seasonal Wind Direction Roses Low Level Winds 1974 - 1987 Season = Fall . . . . . . . . . . . . . . . . . . . 2.2-22 Figure 2.2-4 Surry Seasonal Wind Direction Roses Low Level Winds 1974 - 1987 Season = Winter. . . . . . . . . . . . . . . . . 2.2-23 Figure 2.2-5 Surry Seasonal Wind Direction Roses Low Level Winds 1974 - 1987 Season = Overall . . . . . . . . . . . . . . . . 2.2-24 Figure 2.2-6 Surry Seasonal Wind Direction Roses High Level Winds 1974 - 1987 Season = Spring . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2-25 Figure 2.2-7 Surry Seasonal Wind Direction Roses High Level Winds 1974 - 1987 Season = Summer. . . . . . . . . . . . . . . . . . . . . . . . . 2.2-26

Revision 52Updated Online 09/30/20 SPS UFSAR 2-vii Chapter 2: Site Characteristics List of Figures (continued)

Figure Title Page Figure 2.2-8 Surry Seasonal Wind Direction Roses High Level Winds 1974 - 1987 Season = Fall . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2-27 Figure 2.2-9 Surry Seasonal Wind Direction Roses High Level Winds 1974 - 1987 Season = Winter . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2-28 Figure 2.2-10 Surry Seasonal Wind Direction Roses High Level Winds 1974 - 1987 Season = Overall . . . . . . . . . . . . . . . . 2.2-29 Figure 2.2-11 Surry Seasonal Wind Persistence Roses Low Level Winds 1974 - 1987 Season = Spring . . . . . . . . . . . . . . . . . . . . . 2.2-30 Figure 2.2-12 Surry Seasonal Wind Persistence Roses Low Level Winds 1974 - 1987 Season = Summer. . . . . . . . . . . . . . . . . . . . 2.2-31 Figure 2.2-13 Surry Seasonal Wind Persistence Roses Low Level Winds 1974 - 1987 Season = Fall . . . . . . . . . . . . . . . . . . . . . . . 2.2-32 Figure 2.2-14 Surry Seasonal Wind Persistence Roses Low Level Winds 1974 - 1987 Season = Winter. . . . . . . . . . . . . . . . . 2.2-33 Figure 2.2-15 Surry Seasonal Wind Persistence Roses Low Level Winds 1974 - 1987 Season = Overall . . . . . . . . . . . . . . . . 2.2-34 Figure 2.2-16 Surry Seasonal Wind Persistence Roses High Level Winds 1974 - 1987 Season = Spring. . . . . . . . . . . . . . . . . 2.2-35 Figure 2.2-17 Surry Seasonal Wind Persistence Roses High Level Winds 1974 - 1987 Season = Summer . . . . . . . . . . . . . . . 2.2-36 Figure 2.2-18 Surry Seasonal Wind Persistence Roses High Level Winds 1974 - 1987 Season = Fall . . . . . . . . . . . . . . . . . . . 2.2-37 Figure 2.2-19 Surry Seasonal Wind Persistence Roses High Level Winds 1974 - 1987 Season = Winter . . . . . . . . . . . . . . . . 2.2-38 Figure 2.2-20 Surry Seasonal Wind Persistence Roses High Level Winds 1974 - 1987 Season = Overall . . . . . . . . . . . . . . . . 2.2-39 Figure 2.2-21 Locations of Meteorological Towers . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2-40 Figure 2.3-1 Isovel Field Probable Maximum Hurricane. . . . . . . . . . . . . . . . . . . . . 2.3-21 Figure 2.3-2 Probable Maximum Hurricane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3-22 Figure 2.3-3 Probable Maximum Hurricane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3-23 Figure 2.3-4 Probable Maximum Hurricane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3-24 Figure 2.3-5 Offshore Bottom Profile From Centerline of Chesapeake Bay -

Seaward on Course S 63 E. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3-25 Figure 2.3-6 PMH Surge and Wind Speed at Surry Site . . . . . . . . . . . . . . . . . . . . . 2.3-26

Revision 52Updated Online 09/30/20 SPS UFSAR 2-viii Chapter 2: Site Characteristics List of Figures (continued)

Figure Title Page Figure 2.3-7 Time - Hours After PMH 0 Isovel Passes James River Mouth Surge Hydrographs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3-27 Figure 2.3-8 Factors for Reducing Hurricane Wind Speeds When Center Over Land 2.3-28 Figure 2.3-9 Surge Hydrographs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3-29 Figure 2.4-1 Regional Physiography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-45 Figure 2.4-2 Regional Geology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-46 Figure 2.4-3 Columnar Geologic Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-47 Figure 2.4-4 Site Stratigraphic Column of Quaternary and Upper Miocene Formations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-48 Figure 2.4-5 Plan Location of Borings and Piezometers . . . . . . . . . . . . . . . . . . . . . 2.4-49 Figure 2.4-6 Subsurface ProfilesSheet 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-50 Figure 2.4-7 Subsurface ProfilesSheet 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-51 Figure 2.4-8 Undisturbed Sample Locations Containment Cofferdams. . . . . . . . . . 2.4-52 Figure 2.4-9 Penetration Test Data, Sand A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-53 Figure 2.4-10 Penetration Test Data, Sand B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-54 Figure 2.4-11 Vertical Effective Stress at Sample Location . . . . . . . . . . . . . . . . . . . 2.4-55 Figure 2.4-12 Preconsolidation Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-56 Figure 2.4-13 Interface Locations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-57 Figure 2.4-14 Piezometric Readings - 1970 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-58 Figure 2.4-15 Piezometric Readings - 1970 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-59 Figure 2.4-16 Piezometric Readings - 1970 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-60 Figure 2.4-17 Piezometric Readings - 1971 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-61 Figure 2.4-18 Piezometric Readings - 1971 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-62 Figure 2.4-19 Piezometric Readings - 1971 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-63 Figure 2.4-20 Precipitation Data Vicinity of Surry Station . . . . . . . . . . . . . . . . . . . . 2.4-64 Figure 2.4-21 Ground Motion Due to Earthquake . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4-65 Figure 2.4-22 North-South Section Through Surry Unit 2 . . . . . . . . . . . . . . . . . . . . . 2.4-66 Figure 2.5-1 Regional Tectonics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5-26 Figure 2.5-2 Regional Epicenter Map. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5-27 Figure 2.5-3 Amplification Spectra for Three Typical Earthquakes 10% Damping 2.5-28

Revision 52Updated Online 09/30/20 SPS UFSAR 2-ix Chapter 2: Site Characteristics List of Figures (continued)

Figure Title Page Figure 2.5-4 Amplification Spectra for Four Overburden Depths 10% Damping . . 2.5-29 Figure 2.5-5 Response Spectra Operational-Basis Earthquake . . . . . . . . . . . . . . . . 2.5-30 Figure 2.5-6 Response Spectra Design-Basis Earthquake . . . . . . . . . . . . . . . . . . . . 2.5-31

Revision 52Updated Online 09/30/20 SPS UFSAR 2-x Intentionally Blank

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-1 CHAPTER 2 SITE CHARACTERISTICS This chapter primarily describes the site characteristics for the Surry Power Station as they existed when the facility was licensed. As such, current site characteristics may not agree with these descriptions. The site characteristics described here include geography, demographics, nearby facilities, meteorology, hydrology, geology, and seismology. This information was gathered to support or develop the original plant design bases. Chapter 2 also contains evaluations of these site characteristics demonstrating how applicable siting criteria were met at the time of original licensing of the facility. Because this information is not expected to be used to support current or future plant operations or regulatory activities, Chapter 2 does not need to be updated to reflect minor changes to these site characteristics. However, this does not preclude the need to update this chapter to reflect significant changes to this information.

In the past, minor changes to site characteristics have been incorporated into Chapter 2.

While the updates were not required, these changes have not been removed. Therefore, some parts of this chapter reflect more recent information.

2.1 GEOGRAPHY, DEMOGRAPHY AND POTENTIAL EXTERNAL HAZARDS 2.1.1 Site Location and Description 2.1.1.1 Site Location This section gives a general description of the region surrounding the Surry Power Station.

Additional information can be found in the Surry Station Emergency Plan (Reference 1) and the safety analysis report (Reference 2) supporting the independent spent-fuel storage facility at for the Surry Power Station.

The Surry Power Station is located in Surry County, Virginia, on a point of land called Gravel Neck that juts into the James River from the south, as shown in Figure 2.1-1 and 2.1-16.

The site is at the end of Route 650 and south of and adjacent to the Hog Island State Wildlife Management Area. It is bordered by the James River on either side of the peninsula. The site is 4.5 miles west-north-west of Fort Eustis, 7 miles south of Colonial Williamsburg, and 8 miles east north east of the town of Surry. Jamestown Island, part of the Colonial National Historical Park, is to the northwest on the northern shore of the James River.

The site coordinates are:

Latitude Longitude Universal Transverse Mercator (UTM)

Unit 1 37° 9' 58" N 76° 41' 55" W 4,114,460 mN 349,200 mE zone 18s Unit 2 37° 9' 57" N 76° 41' 53" W 4,114,415 mN 349,280 mE zone 18s The area within 10 miles of the site covers parts of Surry, Isle of Wight, York, and James City Counties, and parts of the cities of Newport News and Williamsburg. Surry and Isle of Wight Counties are predominantly rural and characterized by farmland, wood tracts of land, and marshy

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-2 wetlands. York and James City Counties and the cities of Newport News and Williamsburg are more urban and are characterized by recreational areas and growing population centers. The Hog Island State Wildlife Management Area, immediately north of the site, is reached by a public access road running through the site. Public parking and viewing points are provided by the state within the refuge. The tip of the peninsula is very marshy and almost severed by many streams and creeks.

The region 10 to 30 miles east and southeast of the site is comprised of the Hampton, Newport News, Norfolk, and Portsmouth, Virginia urban areas. This general area is a major Atlantic Coast seaport and U.S. naval base, and the largest industry is shipbuilding. The site is 44 miles southeast of Richmond, Virginia. The Atlantic Ocean lies some 40 miles east of the site.

Figure 2.1-2 shows the site and the general topography over an area to a radius of about 50 miles.

2.1.1.2 Site Description The plant site comprises approximately 830 acres. The plant property lines, which are the same as the site boundary lines, are shown on Figure 2.1-3. Virginia Electric and Power Company (Virginia Power), owns, in fee simple, all of the land within the site boundary, both above and beneath the surface, with the exception of state route 650, which passes through the site to the Hog Island State Wildlife Management Area to the north.

The site boundary is clearly posted to ensure that it will not be transgressed by unauthorized individuals.

The ground surface at the site is generally flat, with steep banks sloping down to the river and to the low-level waterfowl refuge to the north. Station ground grade has been established at an elevation of 26.5 feet above the U. S. Coast & Geologic Survey mean sea level datum at Hampton Roads, Virginia.

Beyond the site boundaries, maximum land elevations within a 5-mile radius are generally in the range of 40 to 60 feet. Much of the region is characterized by marshes, extensive swamps, small streams, and pocosins. Water tables are very near to the surface throughout the entire area, accounting for the large amount of surface waters. Drainage throughout the area is toward Hampton Roads, on the Atlantic Ocean and near the mouth of Chesapeake Bay.

Control of law and order in Surry County is under the jurisdiction of the County Sheriffs Department and the Virginia State Police.

Significant site structures are shown on Figure 2.1-3.

2.1.1.3 Boundaries for Establishing Effluent Release Limits The release limits for liquid and gaseous effluents are based on the unrestricted areas as shown on Figure 2.1-4. For gaseous effluents, the unrestricted area is at or beyond the site boundary. For liquid effluents, the unrestricted area is at the discharge canal. Exposure of individuals to radiation in these areas will be within 10 CFR 20 limits. Since Vepco owns, in fee

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-3 simple, the land within the site boundary, it has total control over access to this area. Access is controlled by the security guard force.

2.1.2 Exclusion Area Authority and Control 2.1.2.1 Authority The Exclusion Area is the site boundary. The minimum distance from a reactor centerline to the site exclusion boundary as defined in 10 CFR 100 is 1650 ft. This is the distance for Unit 1, which is controlling and is sufficient, in conjunction with the plant design, to ensure that the dose limitations of 10 CFR 50.67 are met. Virginia Power has the authority to control activities within the Exclusion Area, including exclusion and removal of personnel and property. Virginia Power has total control over access to this area except for public access on State Route 650 to the Hog Island State Wildlife Management Area to the north of the site. A map of the site is shown in Figure 2.1-3.

2.1.2.2 Control of Activities Unrelated to Plant Operation No activities unrelated to plant operations (other than transit through the area) are permitted in the Exclusion Area without Virginia Power approval.

2.1.2.3 Arrangements for Traffic Control In the event of an emergency, local law enforcement officers will take control of traffic on State Route 650.

2.1.3 Population Distribution 2.1.3.1 Population Within 10 Miles Figure 2.1-1 shows the general locations of the municipalities and other cultural features within 10 miles of the Surry site. As indicated on Figure 2.1-1, the municipalities which are wholly or partly within 10 miles of the site are:

1990 Population1 Distance (miles) from Direction from Surry site Surry site City of Newport News 171,439 4.5 (closest point)2 ESE City of Williamsburg 11,530 7 N Town of Surry 190 8 WSW The population distribution within 10 miles of the site was computed by overlaying 1990 census block data (Reference 3), (the smallest unit of census data), on the grid shown on Figure 2.1-1 and summing the population of the census blocks falling in each of the polar sectors comprising the grid. The population of census blocks shared by more than one polar sector was apportioned based on the fraction of the census block area in each sector.

1. Reference 3

2. Fort Eustis. This is a U. S. Army installation and not part of any local municipality.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-4 The area of a census block is generally inversely proportional to the population of the census block. Thus, an urban census block may be geographically as small as a few city blocks.

However, a sparsely populated rural census block could be several miles across, but include only several residents. As a result, any error from the allocating process should be very small. The 10 mile population distribution for 1990 is shown on Figure 2.1-5.

Population projections for the areas within 10 miles of the Surry site for the years 2000, 2010, 2020 and 2030 are given in Figures 2.1-6 through 2.1-9, even though the current license expiration dates for the two Surry units are 2032 and 2033 respectively. Population projections were based on Virginia Population Projections prepared by the Virginia Employment Commission (Reference 4). For conservatism, the projected population of polar sectors encompassing portions of more than one jurisdiction was escalated at the highest rate among the applicable jurisdictions.

The 1990 resident populations within 5 and 10 miles of Surry Power Station site were 3216 and 122,097 persons, respectively.

2.1.3.2 Population Between 10 and 50 Miles Estimates of the 1990 resident population from 10 to 50 miles from the Surry site were computed using the same methodology used to develop the 10 mile population distribution. The population grid from 10 to 50 miles is shown on Figure 2.1-2 and the 50 mile population distribution for 1990 is shown on Figure 2.1-10.

Population projections for the areas between 10 and 50 miles for the years 2000, 2010, 2020 and 2030 were based on the same methodology as the 10 mile projections. These population projections are given in Figures 2.1-11 through 2.1-14.

The population contribution for the portion of northeastern North Carolina included in the 50 mile radius, which at its closest point is 42 miles from the site, was under 6000. The population growth projection was based on the adjacent Virginia jurisdictions. These jurisdictions are more urban than the included areas of North Carolina.

2.1.3.3 Transient Population Information concerning transient population for the area was collected from several sources as this information is not available from the 1990 census data. The area within 10 miles of the site to the south and west is predominantly rural and characterized by farm land, wooded tracts of land, and marshy wetlands. Since there are no significant industrial or commercial facilities in these directions, and none are anticipated, the transient employment population is likely to be out of, rather than into, the area.

General transient employment population figures in the Williamsburg and Newport News areas within 10 miles of the plant are not available. However, large employers in these areas within 10 miles of the Surry site are listed in Table 2.1-1.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-5 Transient population estimates for the tourist attractions, parks and recreational areas to the north, east and southeast are provided in Table 2.1-2. These figures were obtained from the individual attractions and the Virginia Division of Tourism (Reference 5). Total tourist figures in the Williamsburg area have not changed significantly over the last ten years. Ticket purchases at Colonial Williamsburg (Reference 6) and Jamestown and Yorktown National Historical Parks (Reference 7) have collectively decreased. Busch Gardens (Reference 8), located 5.4 miles NNE of the Surry site, and with an annual attendance of 2.1 million, is the largest single tourist attraction in the 10 mile area. Peak daily figures are estimated based on data provided by the Virginia Division of Tourism (Reference 5).

2.1.3.4 Low Population Zone The Low Population Zone, as shown in Figure 2.1-1, is bounded by a 3 mile-radius circle centered at the Unit 1 reactor containment building. The Low Population Zone boundary was established to ensure that the dose limitation requirements of 10 CFR Part 100 are met.

The resident population distribution within the Low Population Zone is indicated in Figures 2.1-5 through 2.1-9 based on the 1990 census and projections every 10 years through to the year 2030. In summary, the Low Population Zone population for 1990, and the projected population through 2030, are as follows:

1990 145 2000 161 2010 174 2020 186 2030 199 The only significant sources of transient population within the Low Population Zone are noted on Table 2.1-2. Use of the Hog Island State Wildlife Management Area has remained essentially constant since the Surry Station began (Reference 9) operation. Peak annual use of the Chippoaks Plantation State Park dropped from 125,000 in 1989 to 98,000 in 1991 (Reference 10).

Usage recovered to 115,552 in 1993. Future usage could be increased if additional camping facilities are added.

Considering the available road network leading from the Low Population Zone, together with the availability of private as well as public vehicles, there is reasonable assurance that these populations could be evacuated in a timely manner in the event of a design-basis accident.

2.1.3.5 Population Center The nearest population center with more than 25,000 residents is the city of Newport News, which had a 1990 population of 171,439. Fort Eustis, a U. S. Army Base, which is geographically adjacent to Newport News, is within 4.5 miles of the Unit 1 reactor containment building. The closest point of Newport News proper is 7 miles east-south-east of the site. Either of these distances is greater than the population center distance, which is one and one-third times the Low

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-6 Population Zone boundary distance, as required by 10 CFR 100. In addition, the dose limitations of 10 CFR 50.67 or RG 1.183, as applicable, are met with considerable conservatism. There are no closer population centers whose population is likely to reach 25,000 by 2030.

2.1.3.6 Population Density The cumulative resident population in 1990 to a distance of 50 miles in all directions from the plant is compared with the cumulative population resulting from a uniform population density of 500 people/sq. mile in Figure 2.1-15. Similarly, the projected cumulative resident population in 2030 to a distance of 50 miles in all directions from the plant is compared with the cumulative population resulting from a uniform population density of 1000 people/sq. mile.

2.1.4 Nearby Industrial, Transportation, and Military Facilities This section evaluates the effects of potential accidents associated with present and projected nearby industrial, transportation, and military facilities.

2.1.4.1 Location and Routes The James River shipping channel for ships and barges passes within 2.3 miles of the site, as shown on Figure 2.1-16. Route 650, a state secondary road, provides the only land access to the site. Portions of State Routes 10 and 31 pass within 10 miles of the site with the closest approach of State Route 10 being 4.5 miles from the site. The only railway within 10 miles is the CSXT Railway which is 6 miles to the northeast at its nearest approach to the site. The site is bordered on the east and west by the James River and is accessible by water craft at the east side pier. There are three airports within 10 miles of the site, Williamsburg-Jamestown Airport (5 miles NNW),

Felker AAF (5 miles ESE), and Melville (Reference 11). There are no federal airways within 5 miles of the plant (Reference 11). There are no known mines or stone quarries within 5 miles of the site or commercial nuclear facilities within 50 miles of the site.

2.1.4.2 Description of Facilities Lists of facilities and the hazardous materials they used or stored locally were obtained from local fire departments (Reference 12). There are no significant manufacturing facilities located within 5 miles of the Surry site. The closest industrial facility to the site is Anheuser-Busch, a brewery plant (5.5 miles NNE). There are no hazardous materials at the brewery that would pose a credible threat to the Surry site. BASF Corp., which operated the former Dow-Badische synthetic fibers factory 4.9 miles east-north-east, has closed the facility (Reference 13). Other significant facilities within 10 miles of the site are discussed in Table 2.1-1.

The only military installation within 5 miles of the site is the U. S. Army Transportation Center at Fort Eustis (4.5 miles east-south-east, at its closest point) (Reference 14). The U. S.

Naval Reservation, including the U. S. Naval Supply Center, the U. S. Naval Weapons Station (Reference 15) and Camp Peary, occupies a large portion of the land area north and northeast of the site between the James and York Rivers. The U. S. Naval Reservation is bordered to the east-southeast by the Yorktown portion of the Colonial National Historical Park. The U. S. Naval

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-7 Weapons Station lies 6.2 miles northeast of the site. The nature of hazardous materials on these facilities is confidential. Increased activities at these facilities is not anticipated.

2.1.4.3 Pipelines As shown on Figure 2.1-16, Columbia Gas Transmission Corporation and Colonial Pipeline Company own pipelines which cross the southeast corner of the site. A spur pipeline branches into the Surry Site from each of these lines to supply natural gas and No. 2 fuel oil, respectively, to the Gravel Neck Combustion Turbine Facility, which is located south of the intake canal. The Columbia Gas Transmission Corporation pipelines carry only natural gas and there are no plans to transport any other materials. The Colonial Pipeline Company pipeline carries No. 2 fuel oil.

There are no other pipelines within 5 miles of the facility. The specifications of the pipelines are listed below (References 16 & 17).

Line Year Built Diameter Max. Press. Depth Columbia Gas NW Line(1) 1960 8" 600 psi >30" SE Line (St. Rt. 626 to river)(1) 1971 10" 600 psi >30" SE Line (under river)(1) 1982 12" 600 psi >30" Spur to combustion turbines(2) 1969 12" 600 psi >30" Colonial Pipeline Main line(3) 1963 14" o.d. 1181 psi >30" land

> 48" river Spur to combustion turbines(4) 1990 12.75 150 psi >30"

1. Line isolation is provided by manual gate valves at State Route 626 and both sides of the river.

2. Line isolation is provided by manual gate valves at the junction with the transmission pipelines.

3. Line isolation is provided by slab gate valves on each side of the river.

4. Line isolation is provided by a slab gate valve at the junction with the transmission pipeline.

2.1.4.4 Waterways The James River, a major waterway with a 25-foot-deep channel, is navigable by seagoing vessels up to Richmond. A survey of dock facilities upstream of the Surry site was conducted to identify potentially hazardous materials transported past the site. Two categories of vessels use the river, closed container ships and bulk carriers. The container ships carry no Class 1 1 hazardous materials. Other hazardous materials are double contained and quantities are generally small. They are packed in drums or packages that are consolidated in large closed containers.

Container ships pass the site about 80 times per year. Shipment frequency is not expected to increase in the near future (Reference 18).

The only potentially explosive hazardous material routinely shipped in bulk is interface which is a mixture of gasoline and diesel oil that represents the transition between batches of

1. International Maritime Dangerous Goods (IMDG) Code, Hazardous Materials Classification Section

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-8 gasoline and diesel oil in a pipeline. Interface is shipped in 30,000 bbl (1.3 million gallon barges).

These shipments occur several times a month (Reference 19). Other materials, such as phenol, which is shipped in 5.5 million lb lots every few days, and occasional 2000-ton shipments of sulfuric acid are also transported past the site (Reference 20). Other flammable, non-explosive materials include asphalt and No. 6 fuel oil.

One facility shipped a number of barges containing up to 100,000 bbl (4.2 million gallons) of gasoline as recently as December 1991 before the dock was closed. The dock was reopened for one 100,000 bbl shipment in November 1993. However, the operator expects no future shipments and is considering closing the dock permanently (Reference 21).

Chemical compounds shipped along the James River are listed in Reference 22. Quantities and types of materials currently being shipped are similar.

The nearest point of the shipping channel is approximately 1.4 miles from the intake structure. In addition, the river depth at mean high tide for much of the distance between the intake structure and the channel is four feet or less. As a result, shipping on the James River does not constitute a hazard to the intake structure.

2.1.4.5 Roads State secondary Route 650 is the only land access to the Surry site. It ends at the Hog Island State Wildlife Management Area, north of the site. No chemicals or cargo are expected to be transported on this portion of Route 650 unless the chemicals are used by the Surry Power Station.

Chemicals stored onsite and evaluated for control room habitability are listed in Table 2.1-4.

Virginia Highway 10 is the only other primary state route that passes within 5 miles of the site. A list of chemical compounds transported on a regular basis by truck on Virginia Highway 10 in 1981 is also provided in Reference 22. This list was revalidated in 1994. This list does not include shipments of small amounts of chemical compounds shipped to and used by the local farmers and merchants in Surry and Isle of Wight Counties.

2.1.4.6 Airports There are two airports that are just over 5 miles from the site which can be seen on Figure 2.1-17. Information on these airports was obtained from the Virginia Division of Aviation and the individual airports. Williamsburg-Jamestown Airport, 5 miles north-north-west, has a 3200-foot paved runway. There is no control tower. Operations primarily involve single engine light planes and a small number of business jets. The trend of operations over the past few years is essentially flat with approximately 17,000 operations per year. Forty-five planes were based at the airport in 1993. The traffic patterns at the airport are to the southwest and do not normally involve passing over the river (Reference 23).

Felker AAF at Fort Eustis is 5 miles east-south-east of the site. This facility maintains a control tower and has a 3000-foot paved runway. Traffic at Felker is primarily U. S. Army

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-9 helicopters. There is also a flying club that operates light planes out of the facility. Helicopter operations are expected to decrease by 20% following transfer of certain training functions to another facility. Direct over flight of the station below 1500 feet is prohibited. Base legs and cross wind legs are three statute miles from the station (Reference 14).

Melville Airfield is a private grass strip about 6 miles west-south-west of the site. Only one plane is based there and the facility appears to see little use (Reference 24).

None of the airports expect significant facility changes that would affect use. No large commercial jets use any of these facilities. These and other airports potentially affecting the site are listed in Table 2.1-3.

2.1.4.7 Projections of Facility Growth Given their rural nature, none of the facilities in Surry or Isle of Wight Counties are expected to change in the near future.

2.1.5 Evaluation of Potential Accidents 2.1.5.1 Explosions and Flammable Vapor Clouds Possible sources of explosion and formation of flammable vapor clouds include the natural gas or No. 2 fuel oil carried by the pipelines passing near the site or explosive materials/chemicals used by nearby industrial facilities, carried by truck traffic on Virginia Highway 10, or carried by waterborne traffic on the James River.

2.1.5.1.1 Truck Traffic As shown in Reference 22, the largest explosive load transported on Highway 10 contains 8500 gallons of gasoline. The explosive force of this quantity of gasoline is estimated to be equivalent to 50,700 lb of TNT using a simple TNT equivalent yield formula (Reference 25).

According to NRC Regulatory Guide 1.91 (Reference 26), if this amount of gasoline were to explode, a peak overpressure of 1 psi would be experienced about 1900 feet away from the point of explosion; whereas, the closest approach of Highway 10 to the site is 4.5 miles. The value of 1 psi is cited by Regulatory Guide 1.91 as a conservative value of peak positive incident overpressure below which no significant damage would be expected.

Flammable vapor clouds formed from a spill of gasoline on the highway do not present an explosive hazard because gasoline vapor clouds are not known to detonate in unconfined areas (References 27, 28 & 30).

2.1.5.1.2 Waterborne Traffic Traffic on the James River is confined to a dredged ship channel which is approximately 2.3 miles distant from the Unit 1 containment. Interface product, carried by barge, is the only

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-10 chemical transported on the river that would present a potential explosion hazard. These shipments are limited in frequency to several per month.

Since interface product is a mixture of gasoline and diesel fuel, it is less explosive than pure gasoline. Conservatively assuming the whole barge is filled with 1,300,000 gallons of gasoline, and is involved in an explosion, the explosive force generated by this quantity of gasoline is estimated to be equivalent to 7,760,000 pounds of TNT (Reference 25).

Regulatory Guide 1.91 (Reference 26) indicates an overpressure of 1 psi would be experienced about 8000 feet (1.6 miles) downwind of the explosion.

2.1.5.1.3 Industrial Facilities As noted in Table 2.1-1, with the closure of the BASF fiber facility, the only offsite industrial facility within 5 miles of the Surry site using potentially explosive materials is the Propane Air Facility operated by Virginia Natural Gas which is 5 miles to the east-north-east. The propane is contained in buried tanks and does not represent a credible danger to the Surry Station (Reference 29).

The Gravel Neck Combustion Turbine Facility is located within the site boundary south of the intake canal. (See Figure 2.1-3.) The facility can burn either natural gas or No. 2 fuel oil which are fed into the facility through underground pipelines. The facility includes six (6) combustion turbines and has the capability to store approximately 6.5 million gallons of No. 2 fuel oil in three (3) above ground tanks. The facility is equipped with fire protection and fire suppression systems. The following features also help ensure that a fire at Gravel Neck will not adversely affect the Surry Power Station:

1. The Gravel Neck facility is located more than 2000 feet from the Surry Units with the intake canal separating them.

2. The fuel oil from a failed fuel oil storage tank would be contained by the dikes around the tanks.

3. The Gravel Neck facility is located more than 700 feet from the switchyard, over 200 feet from the transmission lines and over 1200 feet from the intake canal.

In addition, the flash point of the No. 2 fuel oil precludes the fuel from exploding under anticipated site conditions.

The combustion turbine casings are designed to contain the fragments of the rotor and associated blading should they fail. This eliminates external missile generation from the Gravel Neck site as a concern.

2.1.5.1.4 Pipelines Pipeline locations are shown in Figure 2.1-16. An explosion of natural gas occurring in the pipelines is considered to be impossible due to the absence of oxygen. However, potential

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-11 explosions may result from ruptured or leaking pipelines. As indicated in Regulatory Guide 1.91 (Reference 26), for an overpressure of about 1 psi to be experienced in the vicinity of the nuclear containments, in excess of the equivalent of 25,000 lb TNT of explosive material would be required.

The amount of natural gas, which would produce an explosive force equivalent to 25,000 lb TNT, corresponds to the contents of a 2.6-mile section of the pipe. In the case of a leaking pipeline, any potential explosion will not involve the whole quantity of the natural gas within the pipeline. This is because the natural gas will be dispersed and carried downwind by the ambient wind as soon as it leaks from the pipeline. For the case of a postulated ruptured pipeline, assuming the whole quantity is involved in an explosion and natural gas is escaping at sonic velocity, it will take more than 12 seconds to empty a 2.6-mile pipe section. The natural gas cloud will eventually occupy a volume of 450,000 ft3 without wind advection. If the gas cloud is advected by a very low wind, i.e., 1 meter per second, the elongated gas cloud will have a diameter of 135 feet. Since an unconfined natural gas vapor cloud is not known to explode (References 27, 28 & 30), and the assumption of an explosion event involving the entire contents of a 2.6-mile section of a natural gas pipeline is a very conservative assumption, the pipelines are not considered a significant hazard to plant operation.

The pipeline carrying No. 2 fuel oil is not considered an explosion hazard due to its flashpoint as discussed in Section 2.1.5.1.3 above.

2.1.5.2 Toxic Chemicals Potentially toxic chemicals associated with control room habitability and currently stored onsite are listed in Table 2.1-4. The list is comparable to that used for the Toxic Release Evaluation reported in Reference 31 and the chemical storage analysis in Reference 35. The effects of Halon release on control room habitability are discussed in Section 9.10.2.2.9 of the UFSAR. The quantity of dimethylamine is limited to 100 pounds (825 gallons of 2% solution) so as to not impact control room habitability as described in Regulatory Guide 1.78.

2.1.5.3 Aircraft Accidents The crash probability due to the flights passing near the Surry site from either of the two airports 5 miles from the site, Felker AAF and Williamsburg-Jamestown Airport, was reported in NUREG/CR-4550 (Reference 32) as about 1 x 10-6 per year, based on an assumed combined operations of 126,500 per year. Based on current actual annual operations of 101,000, the revised crash probability is 8.2 x 10-7. The majority of the general aviation operations from the two airports involve single engine light aircraft weighing less than 4000 lb, with 10% of the Williamsburg operations involving twins and small jets weighing less than 12,500 lb. Such small aircraft pose a minimal risk to the plant.

Melville, which lies 6 miles west-south-west of the site, is a private field with a 2900-foot unpaved runway. Use of the airfield is limited to a low volume of small aircraft. Any aircraft

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-12 accident probability due to operation of Melville airfield will be less than the probability due to operation of the two airports analyzed. There are no other airfields within 10 miles of the site.

Newport News/Williamsburg International Airport (Formerly Patrick Henry), 11 miles east-southeast of the site, is an international airport with 172,000, 109,000 and 180,000 operations in 1983, 1988 and 1993, respectively. In 1993 approximately 37,000 involved commercial aircraft (Reference 33). Based on NUREG-0800 (Reference 34), the probability of a aircraft accident occurring at the Surry site from commercial traffic associated with this airport is estimated to be 1.3 x 10-7 per year. Airports/airfields further away from the site are not considered to be significant in the aircraft accident probability analysis.

2.1 REFERENCES

1. Surry Power Station Emergency Plan, Virginia Electric and Power Company, January 1, 1994, Rev. 36.

2. Virginia Electric and Power Company, Dry Cask Independent Spent Fuel Storage Installation, Surry Power Station, Safety Analysis Report, Volumes 1 and 2, October 1982.

3. U.S. Department of Commerce, Bureau of the Census, 1990 Census of Population, Number of Inhabitants.

4. Virginia Population Projections 2010, with Supplemental projections for 2020 and 2030.

Virginia Employment Commission, June 1993.

5. Virginia Division of Tourism; Mark Brown, Analyst; meeting with D. Hostetler, Grove Engineering, 2/25/94; Fax, 3/7/94.

6. Colonial Williamsburg; Jayma Thibault, Office Manager, Visitors Center; Telecon with Brent Christ, Grove Engineering, 3/10/94.

7. Colonial National Historical Park; Kirk Kehrberg, Interpretive Support Specialist; Fax to Brent Christ, Grove Engineering, 3/10/94.

8. Busch Gardens; Cindy Lemke, Public Affairs; Telecon with Brent Christ, Grove Engineering, 3/9/94.

9. Hog Island State Wildlife Management Area; Clyde Abernathy, Refuge Manager; Telecon with D. Hostetler, Grove Engineering, 2/25/94.

10. Chippokes Plantation State Park; Mary Lou Devincenzi, Program Manager; Telecon with Brent Christ, Grove Engineering, 3/9/94.

11. NOAA, Washington, Sectional Aeronautical Chart, 54th Edition, August 19, 1993.

12. James City County; Trent Funkhouser, Director of Economic Planning; Meeting with Brent Christ, Grove Engineering, 2/25/94.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-13

13. BASF Corp.; Thomas Johnson, Coordinator; letter to Mr. Richard Miller, James City County Fire Department, dated February 7, 1994.

14. Fort Eustis; Ronald A. Johnson, Public Affairs Officer; letter dated March 10, 1994, letter dated April 13, 1994.

15. U.S. Naval Weapons Station; Tom Black, Public Affairs Officer; Telecon with Brent Christ, Grove Engineering, 3/9/94.

16. Columbia Gas Transmission Corp.; Floyd Goodwin, Area Superintendent; letter dated March 3, 1994; telecon with D. Hostetler, Grove Engineering, 4/14/94.

17. Colonial Pipeline Company; D. A. Barrett, Area Engineer; Letter dated April 14, 1994, telecon with D. Hostetler, Grove Engineering, 4/22/94.

18. Independent Container Lines; Thomas Kennedy, V.P., Marine Operations; meeting with Brent Christ, Grove Engineering, 2/16/94.

19. Primary Oil; Judy Reed, Transportation; Telecon with D. Hostetler, Grove Engineering, 3/17/94.

20. Allied Signal; Randy King, Transportation; Telecon with D. Hostetler, Grove Engineering, 3/17/94.

21. Exxon; Bill Bays, Terminal Superintendent; Telecon with D. Hostetler, Grove Engineering, 3/17/94.

22. NUS Corporation, Surry Offsite Toxic Chemical Release Analysis, Rockville, Maryland, June 1981.

23. Williamsburg Jamestown Airport; Jean Waltrip, Airport Manager; Telecon with Brent Christ, Grove Engineering, 3/9/94, Fax, 4/10/94.

24. Melville Airfield; Mrs. William E. Savage, Owner; Telecon with Brent Christ, Grove Engineering, 3/9/94.

25. W. C. Brasie and D. W. Simpson, Guidelines for Estimating Damage from Explosions, Chemical Engineering Process, American Institute of Chemical Engineers, 1968.

26. U.S. Nuclear Regulatory Commission, Evaluations of Explosions Postulated to Occur on Transportation Routes Near Nuclear Power Plants, Regulatory Guide 1.91, Rev. 1, February 1978.

27. U.S. Coast Guard, CHRIS: Hazardous Chemical Data, 1978.

28. V. C. Marshall, Unconfined Vapor-Cloud Explosions, Chemical Engineering, June 14, 1982.

29. Virginia Natural Gas, Ann Chamberlain, Vice President Telecon with D. Hostetler, Grove Engineering, 3/17/94.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-14

30. U.S. Nuclear Regulatory Commission, Safety Evaluation Report, Tennessee Valley Authority, Hartsville Nuclear Plant A and B, NUREG-0014, April 8, 1976.

31. NUS Corporation, Surry Onsite Toxic Chemical Release Analysis, Rockville, Maryland, January 1981.

32. U.S. Nuclear Regulatory Commission NUREG/CR-4550, Vol. 3, Rev 1, Part 3, Analysis of Core Damage Frequency: Surry Power Station, Unit 1; Dec. 1990.

33. Newport News/Williamsburg International Airport; John Mahaphy, Airport Manager; Telecon with Brent Christ, Grove Engineering, 3/9/94, Telecon with D. Hostetler Grove Engineering, 4/11/94.

34. U.S. Nuclear Regulatory Commission, Reactor Safety Study, An Assessment of Accident Risks in U.S. Commercial Nuclear Power Plants, NUREG-0800, July 1981.

35. Dominion Calculation, ME-0655, Rev. 0 and Addendums, SPS Chemical Storage Analysis.

2.1 REFERENCE DRAWINGS The list of Station Drawings below is provided for information only. The referenced drawings are not part of the UFSAR. This is not intended to be a complete listing of all Station Drawings referenced from this section of the UFSAR. The contents of Station Drawings are controlled by station procedure.

Drawing Number Description

1. 11448-FY-1D Plot Plan

Revision 52Updated Online 09/30/20 Table 2.1-1 MAJOR MILITARY, COMMERCIAL AND INDUSTRIAL FACILITIES Facility Locationa Emp. Primary Functions Comments Within Low Population Zone (3 miles)

Gravel Neck Combustion Turbine Facility 2000 feet SW Power generation Alternate fuels, natural gas and #2 fuel oil Within 5 miles Fort Eustis 4.5 miles ESE 18,200 U.S. Transportation Center Recent peak employment was 15,090 in 9/93 Within 10 miles Virginia Natural Gas Propane-Air Plant 5 miles ENE To provide supplemental Liquid Propane stored in gas during times of peak underground tanks load Anheuser Busch Breweryb 5.4 miles NNE 1100 Beer brewery Adjacent to Busch Gardens SPS UFSAR Busch Gardens 5.4 miles NNE 3000 Amusement park U.S. Naval Weapons Storage Facility 6.2 miles NE 2650 Storage of naval weapons Colonial Williamsburgb 7.4 miles N 3000 Historical preservation Includes volunteer workers

a. Closest point

b. Substantial overlap in annual attendance very likely because of close proximity of attractions. Total annual visitors to the Williamsburg area, includ-ing shoppers who do purchase tickets to the attractions, are estimated at 5,000,000 2.1-15

Revision 52Updated Online 09/30/20 Table 2.1-2 TOURIST ATTRACTIONS, PARKS AND RECREATIONAL AREAS Annual Peak Facility Location Usagea dailya Comments Within Low Population Zone (3 miles)

Chippokes Plantation State Park 2.5 miles SW 115,552 14,000 Peak daily use is during 2-day annual Pork, Peanut and Pine Festival (July)

Hog Island State Wildlife Management Adjacent to and 25,000 N/A Visitors to view wildlife. Primarily Area north of site over winter months Waterfowl Refuge, harbors wild geese, 4000 Hunters, by permit only during ducks, deer and cranes, as well as other hunting season of less than 15 days species of wildlife. during Nov., Dec., and Jan.

(Estimates by Refuge Manager)

Within 5 miles Jamestown Colonial National Historical 3.1 miles NW 300,000 1400 Open year round (Probably includes Parkb (Closest point) same peak daily visitors as SPS UFSAR Jamestown Settlement)

Bacons Castle 4.2 miles SSW 6500 50 Open April through October, weekends only, March and November. Closed December Carters Grove Plantationb 4.9 miles NE 259,000 2000

a. 1993 unless otherwise noted

b. Substantial overlap in annual attendance very likely because of close proximity of attractions. Total annual visitors to the Williamsburg area, including shoppers who do purchase tickets to the attractions, are estimated at 5,000,000 2.1-16

Table 2.1-2 (CONTINUED)

Revision 52Updated Online 09/30/20 TOURIST ATTRACTIONS, PARKS AND RECREATIONAL AREAS Annual Peak Facility Location Usagea dailya Comments Within 10 miles Busch Gardensb 5.4 miles NNE 2.1 million 18,000 Open April and October on weekends, May through September full time Jamestown Settlementb 6.2 miles NW 373,000 1750 Open year round (Probably includes same peak daily visitors as Jamestown Colonial National Historical Park)

Colonial Williamsburgb 7.4 miles N 909,000 4000 Open year round. Only includes ticket purchases, i.e. does not include non-paying visitors to the area Water Countryb 7.5 miles NNE 460,000 5000 Open late May through Labor Day SPS UFSAR Yorktown Colonial National Historical 9.2 miles ENE 310,000 1450 Park (Closest point)

a. 1993 unless otherwise noted

b. Substantial overlap in annual attendance very likely because of close proximity of attractions. Total annual visitors to the Williamsburg area, including shoppers who do purchase tickets to the attractions, are estimated at 5,000,000 2.1-17

Revision 52Updated Online 09/30/20 Table 2.1-3 AIRPORTS WITHIN 20 MILES OF THE SITE No. of Operations Longest Runway Distanc e Secto Comm. Total Length Airport Type (miles) r (1993) (1993) kd2 a Orient. (feet) Comments Felker AAF Military 5 ESE None 83,000 12,500 NW-SE 3000 72,000 rotary 11,000 light planeb Williamsburg- Civil 5 NNW None 18,000 12,500 NW-SE 3200 All small aircraftc Jamestown Melville Private 6 WSW None Few 18,000 SSW- 2900 Unpaved strip, no NNE facilities, no planes based there Newport News/ Civil 11 ESE 37,000 180,000 121,000 SW-NE 8000 Nearest facility Williamsburg (was serving commercial Patrick Henry) jets Langley AFB Military 19 ESE None Not Avail. 361,000 WSW- 10,000 Data on operations SPS UFSAR ENE not available

a. 10 miles k = 500 < 10 miles k = 1000

b. Light aircraft are virtually all single engine aircraft weighing less than 4000 lb used by a local flying club. Helicopters currently use range in weight from 3200 lb to 55,000 lb. However, all but two types will be transferred to another facility. The combined annual operations for the two remaining types, UH-1, Huey at 9500 lb and UH-60, Blackhawk at 22,000 lb, are projected to be about 58,000.

c. Operations for 1991, 1992 and 1993 were 17,000, 18,000 and 15,600 respectively. The highest figure was entered in this table. 90% of the operations involve single engine aircraft typically weighing 2000 lbs. with some up to 4000 lb. The remaining operations involve twins and small jets weighing less than 12,500 lb, the runway limit.

2.1-18

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-19 Table 2.1-4 SURRY ONSITE CHEMICALS (Largest Individual Container)

Chemical Quantity Gasoline 4000 gal Halon 7400 lb Sulfuric acid 9000 gal Ammonium hydroxide 1800 gal Carbon dioxide 17 tons No. 2 fuel oil 6,700,000 gal Hydrazine 345 gal Biocide (Bromochloro-5, 1000 lb 5-Dimethylhdantoin)

Ethanolamine 1500 gal Sodium bromide (40%) 3000 gal (6000 gal total)

Sodium hypochlorite (15%) 3000 gal (18,000 gal total)

Dimethylamine (2%) 350 gal

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-20 Figure 2.1-1 TEN MILE SURROUNDING AREA

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-21 Figure 2.1-2 FIFTY MILE SURROUNDING AREA

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-22 Figure 2.1-3 SITE BOUNDARY AND MAJOR STRUCTURES

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-23 Figure 2.1-4 SITE BOUNDARY AND UNRESTRICTED AREAS

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-24 Figure 2.1-5 10 MILE POPULATION DISTRIBUTION- 1990

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-25 Figure 2.1-6 10 MILE POPULATION DISTRIBUTION - 2000

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-26 Figure 2.1-7 10 MILE POPULATION DISTRIBUTION - 2010

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-27 Figure 2.1-8 10 MILE POPULATION DISTRIBUTION - 2020

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-28 Figure 2.1-9 10 MILE POPULATION DISTRIBUTION - 2030

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-29 Figure 2.1-10 50 MILE POPULATION DISTRIBUTION - 1990

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-30 Figure 2.1-11 50 MILE POPULATION DISTRIBUTION - 2000

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-31 Figure 2.1-12 50 MILE POPULATION DISTRIBUTION - 2010

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-32 Figure 2.1-13 50 MILE POPULATION DISTRIBUTION - 2020

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-33 Figure 2.1-14 50 MILE POPULATION DISTRIBUTION - 2030

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-34 Figure 2.1-15 POPULATION DENSITY

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-35 Figure 2.1-16 ADJACENT PIPELINES AND WATERWAYS

Revision 52Updated Online 09/30/20 SPS UFSAR 2.1-36 Figure 2.1-17 LOCATION OF AIRPORTS

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-1 2.2 METEOROLOGY AND CLIMATOLOGY 2.2.1 Meteorological Program 2.2.1.1 Local Meteorology Data acquired by the National Weather Service (References 1 through 6) and summarized by the Environmental Data Service have been utilized to determine the normals, means, and extremes of temperature, precipitation, relative humidity, and fog applicable to the Surry Power Station site region. Site data have been obtained from meteorological instrumentation located at the plant site and summarized for the period March 3, 1974, to December 31, 1987.

Climatological data in this report, indicative of both long term expected values and extreme events, have been provided to represent a range of meteorological conditions that are considered typical for the Surry Power Station site region. Through the years it is expectd that some values may change slightly, however, the values presented in this report are stilel considered to be representative of climatic conditions typical to the site region. Climatological extremes for selected meteorological stations in the region are presented in Table 2.2-1. Normals and extremes of temperature, precipitation, relative humidity, and fog are presented for Richmond and Norfolk in Tables 2.2-2, 2.2-3, and 2.2-4. The closest available fog data for Surry site are from the National Weather Service observation stations at Richmond International Airport, Richmond, and Regional Airport, Norfolk, Virginia. The local climatological data (1980) for Richmond indicates an average of 25-30 days per year of heavy fog, and the local climatological data for Norfolk indicates an average of 20-25 days per year of heavy fog. Heavy fog is defined by the National Weather Service as fog which reduces visibility to 0.25 mile or less (Reference 1). The frequency of fog conditions reported at Surry is expected to be more similar to the annual average of heavy fog reported at Richmond than at Norfolk (References 1 & 2). Surry is in close proximity to the James River and has a rural environment (i.e., land-use characteristics favorable for rapid radiation cooling of the ambient air with high specific humidity due to the close proximity of the River). The occurrence of heavy fog in the Norfolk area is less than in the Richmond area due to the moderating influence of the Atlantic Ocean.

The distribution of wind direction and speed is an important consideration when evaluating transport conditions relevant to site diffusion climatology. There are no significant topographic features that would have any major influence on wind direction distribution.

Seasonal and annual distributions of wind direction recorded at the Surry site meteorological tower for both the upper and lower level are presented in Figures 2.2-1 through 2.2-10. On an annual basis the predominant wind direction at both levels is from the southwest and south-southwest direction. Seasonal variations in average wind speed are presented in Table 2.2-5.

Wind persistence is important when considering potential effects from any radiological release. Wind persistence is defined as a continuous flow from a given direction or range of

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-2 directions. Periods of maximum wind persistence in 22.5 degree sectors recorded at the Surry site meteorological tower are presented in Figures 2.2-11 through 2.2-20. The maximum persistence period at the upper level was for 28 hours3.240741e-4 days 0.00778 hours 4.62963e-5 weeks 1.0654e-5 months , once from the south and once from the north-northeast.

At the lower level, the maximum persistence period was 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months from the west-southwest.

Atmospheric stability refers to the degree of wind turbulence. Stable conditions are associated with low turbulence and poor diffusion capability. Unstable conditions are associated with a high degree of turbulence and favorable diffusion characteristics. Atmospheric stability is classified into horizontal and vertical stability categories. The degree of wind variance or standard deviation of direction (sigma-theta) is used to determine horizontal stability. The vertical temperature differential (delta T) is used to determine vertical stability. The classification of sigma-theta data is presented in Table 2.2-6 and the classification of delta T data is presented in Table 2.2-7. The seasonal and annual frequency of horizontal (sigma-theta) stability classes and associated wind speeds for the Surry site are presented in Table 2.2-9. These distributions indicate that the wind is more stable at the upper level than at the lower level. Seasonal variations of the stability distribution presented are minor.

Table 2.2-1 lists some extremes of meteorological measurements for selected National Weather Service stations in the Surry region. The maximum amount of precipitation recorded at Norfolk for a 24-hour period was 11.4 inches which occurred in August of 1964. The maximum amount of precipitation recorded at Richmond for a 24-hour period was 8.79 inches during August 1955. The maximum monthly snowfall measured in the Norfolk area was 18.9 inches during February 1980, and the maximum monthly snowfall measured in Richmond was 28.5 inches during January 1940. The maximum 24-hour snowfalls observed were 21.6 inches at Richmond during January of 1940 and 12.4 inches at Norfolk in February 1980 (References 1

& 2). Once again, while these extreme values may change slightly through the years, they are still considered to be representative of extreme conditions typical to the site region.

2.2.1.2 Onsite Meteorological Measurements Program There are two towers installed on the Surry site. Their locations are illustrated on Figure 2.2-21. The primary site monitors wind direction and wind speed at two levels of the tower, ambient air temperature at the lower tower level, differential air temperature between tower levels, horizontal wind direction fluctuation at both tower levels, dewpoint temperature at the lower tower level, and rainfall at the base of the tower. The backup site monitors wind direction, wind speed, and horizontal wind direction fluctuation.

The nearest structures are 500 feet north-northwest and 150 feet northwest of the primary and backup towers, respectively. At the primary site, the nearest continuous tree line is approximately 50 feet south of the tower. Tree heights are 40 to 50 feet. At the backup site, the nearest tree line, with trees 10 to 15-feet high, is located approximately 50 feet south-southwest of the tower.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-3 The primary tower is a guyed, triaxial, open-latticed structure. On May 21, 2012, the primary tower wind and temperature instrument elevations were surveyed. Table 2.2-8 provides the survey and pre-survey above ground level (agl) instrument heights.

The backup tower is a freestanding, triaxial, open-latticed structure. The instrumentation on the backup tower is located at approximately 30.3 feet agl.

On the primary tower, the wind speed, wind direction, and sigma-theta sensors are mounted on booms longer than one-and-one-half times the tower face width. On the backup tower, the sensors are postmounted on top of the tower. The wind sensors are positioned such that the towers do not influence the prevailing south-southwest wind flow detected by the sensors. Temperature, differential temperature, and dewpoint temperature sensors are housed in motor-aspirated shields to insulate them from thermal radiation from the tower, solar, and terrestrial radiation.

Meteorological monitoring instrumentation is calibrated not less than semiannually.

Inspection, service, and maintenance are performed as required to ensure adequate data recovery.

Redundant recording systems are incorporated into the program to minimize data loss due to recorder failure. The data are listed, reviewed, and summarized into joint frequency distributions by using the atmospheric stability classification scheme shown in Table 1 of Regulatory Guide 1.23 (Proposed Revision 1).

Data from the sites primary and backup meteorological towers are transmitted to the control room and collected by the emergency response facility data acquisition system (ERFDAS). These parameters have been placed in the ERFDAS data base, thus making site meteorological field data available for display in the Technical Support Center (TSC), and the Corporate Emergency Response Center (CERC). Certain information is also hardwired for display on the control room meteorological panels. Table 2.2-10 identifies meteorological information transmitted and its display location. Additional information on emergency response facilities can be found in the Station Emergency Plan.

Temperature, differential temperature, wind speed, and wind direction from both the lower and upper primary tower level sensors are displayed on recorders in the control room, as are wind speed, wind direction, and sigma-theta from the backup tower.

A shelter is located at the base of each tower. The shelters have thermostatically-controlled heat and air conditioning to maintain an interior temperature within a range appropriate for proper equipment operation. The enclosures are located to minimize any micrometeorological effects on the tower instrumentation.

Inside the shelters, the signals are routed to the appropriate signal-conditioning equipment which go to (1) digital data recorders and (2) an interface with the intelligent remote multiplexer system.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-4 Microprocessor-based data acquisition systems are the primary method of data collection for offsite historical files. In addition to being transmitted real-time to the control room recorders and to the ERFDAS, the data from the primary data collection system are telemetered daily to a computer in the corporate office. The data are then reviewed for representativeness and reasonability, including a comparison with data from other Company meteorological tower sites.

Monthly, the data are transferred to the corporate mainframe computer for inclusion in the historical database. Backup collection consists of several remote data acquisition systems.

Meteorological instrumentation and data recording described above was upgraded to be consistent with Regulatory Guide 1.23, Onsite Meteorological Programs, Proposed Revision 1, and Regulatory Guide 1.97, Revision 3, Instrumentation for Light-water Cooled Nuclear Power Plants to Assess Plant and Environs Conditions During and Following an Accident, May 1983.

The meteorological sites and towers are consistent with Regulatory Guide 1.23, Onsite Meteorological Programs, February 1972.

2.2.2 Climate Data acquired by the National Weather Service (NWS) and summarized by the Environmental Data Service (EDS) were used to determine the regional climatology pertinent to the Surry site. References 1 and 2 were used to determine the climatological characteristics of Richmond and Norfolk, Virginia, and Reference 7 for the climatological characteristics of the region.

The Surry site is situated in a humid subtropical climate which is characterized by warm, humid summers and mild winters. During the summer months, this region is dominated by tropical maritime air masses, while during the winter season this area is in a transitional zone between polar continental and tropical maritime air masses.

The climatic characteristics of the site region are influenced by the Atlantic Ocean, the Chesapeake Bay, and the Appalachian Mountains. The Atlantic Ocean has a moderating effect on the temperature for the Surry region, whereas the Appalachians act as a barrier to deflect midwest winter storms to the northeast of the Surry region. Winters are mild and short, spring and fall weather is usually very comfortable, and summers are long, hot, and humid, frequently tempered by cool periods associated with east and northeast winds off the Atlantic Ocean.

Snow is not common during winter in the Tidewater area of Virginia. (The Tidewater area is defined as the Coastal Plain area of Virginia extending west to the Fall Line.) A snowfall of 10 inches or more a month in the Tidewater area is expected to occur once every 4 years. In general, the total accumulated snow for the Tidewater is approximately 10 inches each year.

Precipitation occurs mostly as rain in the site area. The summer months are usually associated with the greatest amount of precipitation. However, great amounts of rainfall have occurred during the fall season associated with the passages of tropical storms or hurricanes.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-5 The Bermuda high that develops off the coast of the United States during the spring and summer seasons results in a moist, southerly flow of air from the Caribbean and South Atlantic to the Surry region. During the fall and winter seasons, a semipermanent high-pressure cell develops over the midwest region of the United States, resulting in a prevailing northwesterly flow of air into the Surry region. The mean annual wind speed for the Norfolk area is approximately 11 mph, and the mean annual wind speed for Richmond is approximately 8 mph.

Thunderstorms are frequent during the summer months with the greatest occurrence during the month of July. Only a small percentage of the thunderstorms can be classified as severe.

Approximately four tornados are reported in Virginia each year, with the majority occurring east of the Blue Ridge Mountains.

An average of less than two hurricanes each year comes close enough to the coast to affect Virginia. These hurricanes can bring torrential rainfall to the Tidewater area, and high tides that result in flood conditions for low-lying areas along the coast. However, less than one hurricane per year actually crosses the state. A typical hurricane to affect the Tidewater area was Hurricane Dennis (August 1981), which brought 2.4 inches of rainfall to the Norfolk area and 0.25 inch to the Richmond area.

2.2.2.1 Tornadoes During the period of January 1951 through December 1987, a total of 49 tornadoes on land have been reported within a 50-mile radius of the Surry site for an average of 1.3 tornadoes per year within this radius. As additional years of data are included in the analyses, it is expected that averages may change slightly. However, the averages presented in this report are still considered to be appropriate estimates of conditions typical to the site region.

The probability of a tornado striking a point within a given area may be estimated as follows (Reference 8):

zt P = ----

A Where:

P = the mean probability per year z = the geometric mean tornado path area t = the mean number of tornadoes per year observed in the area of concern A For the region surrounding the Surry site, the computed geometric mean tornado path length was about 1.6 miles and the computed geometric mean path width reported was about 118 yards, based on examination of reported tornado statistics (Reference 9). These values yield a z of 0.106 square miles based on tornado data for the period of January 1951 through December 1987.

Using a 50-mile radius as a basis for A (excluding the Chesapeake Bay) and a value of

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-6 1.3 tornadoes per year for t, yields a probability of 1.73 x 10-5 per year, or a recurrence interval of about 58,000 years.

The Class 1 structures and systems, or parts thereof, whose failure might prevent the simultaneous cold shutdown of both reactor units during a loss-of-power incident will withstand by design a tornado with the following characteristics and associated effects:

1. Rotational wind velocity of 300 mph.

2. A pressure drop of 3 psi in 3 seconds.

3. Translational velocity of 60 mph.

4. Missile equivalent to a wooden utility pole 40-foot long, with 12-inch diameter, weighing 50 lb/ft3, and traveling in a vertical or horizontal direction at 150 mph.

5. Missile equivalent to a 1-ton automobile traveling at 150 mph.

The pressure change and translational velocity above have been adopted from the license applications of others. The pressure change of 3.0 psi is considered conservative. The greatest officially observed pressure change near a tornado was 0.34 psi (which occurred in a 2-minute period) recorded at the Topeka Airport on June 8, 1966, as reported by Galway (Reference 10).

The published work of Brooks (Reference 11) and Glaser (Reference 12) suggests that wind velocities of 220 to 300 mph would be produced by a central pressure difference of 1.1 to 1.5 psi.

Before adopting the tornado characteristics above, a tornado model was prepared to develop pressure and wind velocity criteria that were physically consistent. This tornado model was similar to the one suggested by Hoecker (Reference 13). The model included the following tornado specifications:

1. Overall diameter, 1000 ft.

2. Central pressure, 13.0 psia.

3. Central pressure difference, 1.5 psi.

4. Maximum pressure gradient, 0.02 psi/ft.

5. Radius of maximum winds, 200 ft.

Using this pressure structure and the cyclostrophic wind equation, an estimate of the maximum winds that would occur within such a tornado was obtained as follows (Reference 14):

rg p V2 = ----- ---

r where:

p/ r = maximum pressure gradient, 2.88 lb/ft2/ft (0.02 psi/ft) r = radius of maximum wind, 200 ft

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-7

= density of air, 0.075 lb/ft3 g = 32.2 ft/sec2 V = maximum wind velocity, fps The calculated maximum wind velocity of 338 mph compares with the design wind velocity of 300 mph, which is based on observed structural damage. Thus, the modeled tornado pressure distribution with a central pressure difference of 1.5 psi and a maximum pressure gradient of 0.02 psi/ft is physically consistent with accepted estimates of wind speeds associated with tornadoes. The model and derived estimates are also in agreement with the published works of Brooks, Glaser, and Hoecker. While the pressure difference of 1.5 psi is consistent with the other tornado characteristics chosen, the more conservative pressure difference of 3.0 psi has been used.

2.2.2.2 Extreme Winds Extreme wind data were obtained from studies by Thom (Reference 15) and Huss (Reference 16). Severe weather data were obtained from a variety of sources. Severe storm, tornado, and hurricane data were obtained from References 8, 9, 17, 18 and 19.

According to Thom, the extreme 1-mile wind speed at 30 feet above the ground for a 100-year recurrence interval for the Surry region is 105 mph. Based on a gustiness factor of 1.3 according to Huss, the highest instantaneous gust expected once in 100 years is 137 mph.

The fastest mile wind recorded at Norfolk based on the 1953 to 1987 period of record was a southerly wind with a speed of 78 mph (Reference 2). The fastest mile wind recorded at Richmond based on the 1951 to 1987 period of record was a southeasterly wind with a speed of 68 mph (Reference 1). Both of these extreme wind speeds occurred during the passage of Hurricane Hazel in October 1954. While greater extreme wind speeds may occur in the future, these values are considered to be representative of extreme conditions typical to the site region.

2.2.2.3 Tropical Storms and Hurricanes Since 1871 (when more complete weather recordkeeping began) through 1987, a total of 56 tropical storms or hurricane centers passed within 100 nautical miles of the Surry site (References 9 & 18). After 1885, weather records differentiated between tropical storms (less that 73 mph) and hurricanes (greater than 73 mph). From 1886 through 1987, there have been 34 passages of tropical storms, and 10 hurricanes have passed within 100 nautical miles of the site.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-8

2.2 REFERENCES

1. National Oceanic and Atmospheric Administration, Richmond, Virginia, 1987, Local Climatological Data, Annual Summary with Comparative Data, Environmental Data Services, Asheville, North Carolina.

2. National Oceanic and Atmospheric Administration, Norfolk, Virginia, 1987, Local Climatological Data, Annual Summary with Comparative Data, Environmental Data Service, Asheville, North Carolina.

3. National Oceanic and Atmospheric Administration, Climatological Data, Virginia, Annual Summary, 1987, Environmental Data Service, Asheville, North Carolina, 1988.

4. C. W. Crockett, Climatological Summaries for Selected Stations in Virginia - Holland, Water Resources Research Center, Virginia Polytechnic Institute and State University, 53, Blacksburg, Virginia, 1972.

5. C. W. Crockett, Climatological Summaries for Selected Stations in Virginia - Hopewell, Water Resources Research Center, Virginia Polytechnic Institute and State University, 53, Blacksburg, Virginia, 1972.

6. C. W. Crockett, Climatological Summaries for Selected Stations in Virginia - Williamsburg, Water Resources Research Center, Virginia Polytechnic Institute and State University, 53, Blacksburg, Virginia, 1972.

7. U.S. Department of Commerce, Climates of the States, Climate of Virginia, Climatography of the United States No. 60-44, Washington, D.C., 1981.

8. H. C. S. Thom, Tornado Probabilities, Monthly Weather Review 91, pp. 730-736 (1963).

9. National Oceanic and Atmospheric Administration, Storm Data, National Weather Records Center, Environmental Data Service, Asheville, North Carolina.

10. J. C. Galway, The Topeka Tornado of June 8, 1966, Weatherwise, Vol. 19, No. 4, August 1966.

11. E. M. Brooks, Tornadoes and Related Phenomena, Compendium of Meteorology, American Meteorological Society, Waverly Press, Inc., Baltimore, Maryland, 1951.

12. A. H. Glaser, Tornado Studies, Final Report, Texas A & M, January 1956.

13. W. H. Hoecker, Three-Dimensional Pressure Pattern of the Dallas Tornado and Some Resultant Implications, Monthly Weather Review, December 1961.

14. R. E. Huschke, Glossary of Meteorology, American Meteorological Society, Boston, Massachusetts, 1959, p. 151.

15. H. C. S. Thom, New Distribution of Extreme Mile Winds in the United States, ASCE Environmental Engineering Conference, Dallas, Texas, February 1967.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-9

16. P. O. Huss, Relation Between Gusts and Average Wind Speed, Report 140, David Guggenheim Airship Institute, Report 140, Cleveland, Ohio, 1946.

17. Climatological Data - National Summary, U.S. Department of Commerce, Weather Bureau, 1951-1958.

18. C. W. Cry, Tropical Cyclones of the North Atlantic Ocean, Technical Paper No. 55, National Oceanic and Atmospheric Administration, Washington, D.C., 1965.

19. National Oceanic and Atmospheric Administration, Climatological Data, Virginia, Environmental Data Service, Asheville, North Carolina, June 1982.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-10 Table 2.2-1 SELECTED NATIONAL WEATHER SERVICE STATIONS FOR METEOROLOGICAL EXTREMES IN THE SURRY SITE REGION (DATE OF OCCURRENCE)

Norfolk Richmond Maximum temperature, °F 104 (8/80) 105 (7/77)

Minimum temperature, °F -3 (1/85) -12 (1/40)

Maximum monthly rainfall, in. 13.8 (9/79) 18.87 (7/45)

Maximum monthly snowfall, in. 18.9 (2/80) 28.5 (1/40)

Maximum 24-hr rainfall, in. 11.4 (8/64) 8.79 (8/55)

Maximum 24-hr snowfall, in. 12.4 (2/80) 21.6 (1/40)

Fastest mile wind, mph 78 S (10/54) 68 SE (10/54)

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-11 Table 2.2-2 NORMALS, MEANS, AND EXTREMES - RICHMOND, VIRGINIA

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-12 Table 2.2-2 (CONTINUED)

NORMALS, MEANS, AND EXTREMES - RICHMOND, VIRGINIA

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-13 Table 2.2-3 NORMALS, MEANS, AND EXTREMES - NORFOLK, VIRGINIA

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-14 Table 2.2-3 (CONTINUED)

NORMALS, MEANS, AND EXTREMES - NORFOLK, VIRGINIA

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-15 Table 2.2-4 MONTHLY METEOROLOGICAL MEANS FOR TEMPERATURE AND PRECIPITATION FOR STATIONS IN THE SURRY SITE REGION Month Norfolk Richmond January Temp, °F 39.9 36.6 Precipitation, in. 3.72 3.23 February Temp, °F 41.1 38.9 Precipitation, in. 3.28 3.13 March Temp, °F 48.5 47.2 Precipitation, in. 3.86 3.57 April Temp, °F 58.2 57.8 Precipitation, in. 2.87 2.90 May Temp, °F 66.4 66.1 Precipitation, in 3.75 3.55 June Temp, °F 74.3 73.5 Precipitation, in. 3.45 3.60 July Temp, °F 78.4 77.8 Precipitation, in. 5.15 5.14 August Temp, °F 77.7 76.8 Precipitation, in. 5.33 5.01 September Temp, °F 72.2 70.2 Precipitation, in. 4.35 3.52 October Temp, °F 61.3 58.6 Precipitation, in. 3.41 3.74 November Temp, °F 51.9 48.9 Precipitation, in. 2.88 3.29 December Temp, °F 43.5 39.9 Precipitation, in. 3.17 3.39 Annual Temp, °F 59.5 57.7 Precipitation, in. 45.22 44.07

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-16 Table 2.2-5 SURRY SEASONAL AND ANNUAL MEAN WIND SPEED

SUMMARY

(MPH) 1974 - 1987 Upper Level Lower Level Spring 10.6 6.3 (March, April, May)

Summer 8.8 4.9 (June, July, August)

Fall 9.4 5.1 (September, October, November)

Winter 10.3 6.0 (December, January, February)

Annual 9.7 5.6 Table 2.2-6 HORIZONTAL () STABILITY CATEGORIES Range of Standard Stability Category Atmospheric Turbulence Deviation (degrees)

A - extremely unstable 22.5 High B - unstable 22.5 > 17.5 High C - slightly unstable 17.5 > 12.5 High D - neutral 12.5 > 7.5 Moderate E - slightly stable 7.5 > 3.8 Low F - stable 3.8 > 2.1 Low G - extremely stable 2.1 > Low

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-17 Table 2.2-7 VERTICAL (T) STABILITY CATEGORIES Range of Vertical Range of Vertical Temperature Temperature Stability Category Atmospheric Turbulence Gradient Gradient

(°C/100 m) (°F/1000 ft)

A - very unstable T < -1.9 T < -10.4 High B - moderately unstable -1.9 T < -1.7 -10.4 T < -9.3 High C - slightly unstable -1.7 T < -1.5 -9.3 T < -8.2 High D - neutral -1.5 T < -0.5 -8.2 T < -2.7 Moderate E - slightly stable -0.5 T < 1.5 -2.7 T < 8.2 Low F - moderately stable 1.5 T < 4.0 8.2 T < 22.0 Low G - very stable 4.0 T 22.0 T Low Table 2.2-8 PRIMARY MET TOWER INSTRUMENT HEIGHTS (AGL)*

Level Instrument Pre-Survey Survey**

Upper Wind 150.0 ft 151.2 ft Temperature 147.4 ft 149.4 ft Lower Temperature 31.5 ft 35.4 ft Wind 34.0 ft 34.7 ft Dew Point 31.5 ft N/S

(agl) above ground level

- Primary tower wind and temperature instruments surveyed 05/21/2012 but dew point not surveyed N/S

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-18 Table 2.2-9 SURRY SEASONAL AND ANNUAL STABILITY AND WIND SPEED DISTRIBUTION 1974 - 1987 A B C D E F G Spring (Mar, Apr, May)

Upper frequency, % 3.97 4.22 13.55 44.68 26.61 5.11 1.87 Wind Speed, mph (5.4) (6.8) (9.0) (11.5) (10.3) (8.6) (7.9)

Lower frequency, % 5.55 18.89 36.03 31.60 6.52 1.02 0.39 Wind Speed, mph (7.8) (10.4) (10.7) (11.1) (7.9) (5.6) (6.6)

Summer (June, July, Aug)

Upper frequency, % 5.46 5.65 14.86 37.26 27.22 6.81 3.11 Wind Speed, mph (5.0) (6.1) (7.6) (9.3) (8.7) (7.7) (7.4)

Lower frequency, % 10.36 19.75 30.34 31.37 9.81 1.65 1.72 Wind Speed, mph (6.2) (7.9) (8.4) (8.4) (6.8) (5.6) (4.5)

Fall (Sept, Oct, Nov)

Upper frequency, % 3.29 3.49 10.83 37.37 31.65 8.12 5.60 Wind Speed, mph (5.3) (6.1) (8.1) (10.3) (9.4) (8.1) (7.1)

Lower frequency, % 9.95 20.35 33.55 28.80 9.73 1.74 1.01 Wind Speed, mph (6.9) (8.6) (9.1) (8.8) (7.1) (5.6) (5.5)

Winter (Dec, Jan, Feb)

Upper frequency,% 2.66 2.94 9.08 45.55 30.72 6.41 3.03 Wind Speed, mph (4.9) (6.1) (8.1) (11.5) (10.1) (8.3) (7.3)

Lower frequency,% 5.88 17.55 37.73 41.29 10.25 1.43 1.33 Wind Speed, mph (6.3) (8.2) (9.2) (9.8) (7.4) (6.4) (3.1)

Annual Upper frequency,% 3.83 4.06 12.04 41.08 29.04 6.63 3.43 Wind Speed, mph (5.1) (6.3) (8.2) (10.7) (9.6) (8.1) (7.3)

Lower frequency,% 8.04 18.84 32.85 30.91 8.60 1.42 1.04 Wind Speed, mph (6.7) (8.9) (9.4) (9.5) (7.2) (5.6) (4.6)

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-19 Table 2.2-10 METEOROLOGICAL INFORMATION DISPLAY LOCATIONS Transmitted Locations ERFDAS Control Remote Primary Tower Parameters Data base Room Interrogation Wind direction (upper) x x x Wind speed (upper) x x x Sigma theta (upper) x Wind direction (lower) x x x Wind speed (lower) x x x Sigma theta (lower) x Ambient temperature (lower) x x x Dewpoint temperature (lower) x Delta ambient temperature (upper-lower) x x x Precipitation x Transmitted Locations ERFDAS Control Remote Backup Tower Parameters Data base Room Interrogation Wind speed x x x Wind speed x x x Sigma theta x x x Note: All parameters going to the ERFDAS data base will be available for printout in the TSC and CERC. The control room parameters are hardwired.

Remote readout of instrumentation is available at the primary and backup meteorological sites and from the Air Quality Departments system computer.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-20 Figure 2.2-1 SURRY SEASONAL WIND DIRECTION ROSES LOW LEVEL WINDS 1974 - 1987 SEASON = SPRING

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-21 Figure 2.2-2 SURRY SEASONAL WIND DIRECTION ROSES LOW LEVEL WINDS 1974 - 1987 SEASON = SUMMER

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-22 Figure 2.2-3 SURRY SEASONAL WIND DIRECTION ROSES LOW LEVEL WINDS 1974 - 1987 SEASON = FALL

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-23 Figure 2.2-4 SURRY SEASONAL WIND DIRECTION ROSES LOW LEVEL WINDS 1974 - 1987 SEASON = WINTER

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-24 Figure 2.2-5 SURRY SEASONAL WIND DIRECTION ROSES LOW LEVEL WINDS 1974 - 1987 SEASON = OVERALL

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-25 Figure 2.2-6 SURRY SEASONAL WIND DIRECTION ROSES HIGH LEVEL WINDS 1974 - 1987 SEASON = SPRING

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-26 Figure 2.2-7 SURRY SEASONAL WIND DIRECTION ROSES HIGH LEVEL WINDS 1974 - 1987 SEASON = SUMMER

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-27 Figure 2.2-8 SURRY SEASONAL WIND DIRECTION ROSES HIGH LEVEL WINDS 1974 - 1987 SEASON = FALL

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-28 Figure 2.2-9 SURRY SEASONAL WIND DIRECTION ROSES HIGH LEVEL WINDS 1974 - 1987 SEASON = WINTER

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-29 Figure 2.2-10 SURRY SEASONAL WIND DIRECTION ROSES HIGH LEVEL WINDS 1974 - 1987 SEASON = OVERALL

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-30 Figure 2.2-11 SURRY SEASONAL WIND PERSISTENCE ROSES LOW LEVEL WINDS 1974 - 1987 SEASON = SPRING

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-31 Figure 2.2-12 SURRY SEASONAL WIND PERSISTENCE ROSES LOW LEVEL WINDS 1974 - 1987 SEASON = SUMMER

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-32 Figure 2.2-13 SURRY SEASONAL WIND PERSISTENCE ROSES LOW LEVEL WINDS 1974 - 1987 SEASON = FALL

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-33 Figure 2.2-14 SURRY SEASONAL WIND PERSISTENCE ROSES LOW LEVEL WINDS 1974 - 1987 SEASON = WINTER

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-34 Figure 2.2-15 SURRY SEASONAL WIND PERSISTENCE ROSES LOW LEVEL WINDS 1974 - 1987 SEASON = OVERALL

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-35 Figure 2.2-16 SURRY SEASONAL WIND PERSISTENCE ROSES HIGH LEVEL WINDS 1974 - 1987 SEASON = SPRING

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-36 Figure 2.2-17 SURRY SEASONAL WIND PERSISTENCE ROSES HIGH LEVEL WINDS 1974 - 1987 SEASON = SUMMER

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-37 Figure 2.2-18 SURRY SEASONAL WIND PERSISTENCE ROSES HIGH LEVEL WINDS 1974 - 1987 SEASON = FALL

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-38 Figure 2.2-19 SURRY SEASONAL WIND PERSISTENCE ROSES HIGH LEVEL WINDS 1974 - 1987 SEASON = WINTER

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-39 Figure 2.2-20 SURRY SEASONAL WIND PERSISTENCE ROSES HIGH LEVEL WINDS 1974 - 1987 SEASON = OVERALL

Revision 52Updated Online 09/30/20 SPS UFSAR 2.2-40 Figure 2.2-21 LOCATIONS OF METEOROLOGICAL TOWERS

Revision 52Updated Online 09/30/20 SPS UFSAR 2.3-1 2.3 HYDROLOGY 2.3.1 Surface Water Hydrology 2.3.1.1 General Much of the region is characterized by marshes, extensive swamps, small streams, and pocosins. Water tables are very near the surface throughout the entire area, accounting for the large amount of surface waters. Drainage throughout the area is towards Hampton Roads, near the mouth of the Chesapeake Bay, and on to the Atlantic Ocean via the James River.

The James River is formed by the junction of the Cowpasture and Jackson Rivers in Botetourt County, Virginia, and flows easterly 340 miles before emptying into Hampton Roads at Newport News, Virginia.

The flow of water in the James River at the site consists of three components:

1. Fresh water discharge from the James River watershed.

2. Flow due to the oscillatory ebb and flood of the tide.

3. FLOW due to the circulation pattern caused by intrusion of saline water within the estuary.

The drainage area of the James River above the station site is 9517 square miles. The drainage area above the nearest gauge on the main stem of the James River near Richmond is 6757 square miles. An additional 1638 square miles of drainage area of tributaries between Richmond and the plant site is gauged, leaving 1122 square miles ungauged. Discharge records for the gauged tributaries below Richmond were used to estimate the discharge from the ungauged areas, and the total mean monthly discharge for each month for the period October 1934 to September 1993 was computed by summing the discharges from the gauged and ungauged watershed areas. These data are shown in Table 2.3-1 (References 1, 2, & 20).

In compiling the river discharge data, monthly mean flows have been used rather than daily mean flows. This choice was made because the cross-sectional area of the waterway in the 50 miles or so of tidal water between the station and Richmond increases significantly when compared with the stream above Richmond, and there is also a somewhat irregular, but significant, progressive increase in the cross-sectional area in this reach with distance downstream. The mean travel time for a flow of 14,000 cfs (a flow that is exceeded only 25% of the time) from Richmond to the site exceeds 20 days. Therefore, it can be assumed that short-period fluctuations in discharge at Richmond are considerably dampened at the station site.

Further, within the estuary proper there is considerable inertia in the response of the salinity pattern and the net non-tidal circulation to rapid variations in river discharge, thereby providing additional damping.

The 85-mile stretch of the James River between Richmond and the mouth of the river is subjected to tidal motion and is hence a tidal estuary. The site is located in the transition region

Revision 52Updated Online 09/30/20 SPS UFSAR 2.3-2 between the fresh water tidal river and the saline waters of the estuary proper. At a river discharge of about 10,000 cfs, the upstream portion of the site is in the fresh water river, and the salinity at the downstream side of the site is about 1 part/thousand. For river discharges less than 10,000 cfs (a condition occurring approximately 60% of the time), the water on both the upstream and downstream sides of the site will have varying concentrations of ocean-derived salts, depending on river discharge.

The tide in the James River is a semidiurnal tide, with two high waters and two low waters each lunar day of 24.84 hours9.722222e-4 days 0.0233 hours 1.388889e-4 weeks 3.1962e-5 months . The oscillatory ebb and flood of this tide constitute the dominant motion in the waterway in the vicinity of the site. The net downstream flow required to discharge the fresh water seaward through any waterway cross section represents but a small fraction of the tidal flows.

The U. S. Coast and Geodetic Survey (USC&GS) tidal current tables (Reference 3) show that the ebb current is longer and stronger than the flood current at the site. The average of maximum ebb currents is 1.3 knots (2.2 ft/sec) and the average of maximum flood currents is 1.1 knots (1.9 ft/sec). During spring tides, the ebb currents reach a maximum of 1.9 knots (3.2 ft/sec) and the flood currents a maximum of 1.6 knots (2.8 ft/sec). During the typical tidal period of 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months , 25 minutes, the current, on the average, will ebb for 7 hours8.101852e-5 days 0.00194 hours 1.157407e-5 weeks 2.6635e-6 months , 5 minutes, and flood for 5 hours5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months , 20 minutes. It should be noted that the data used to compile the USC&GS tables are based on near surface observations, made during periods of normal river discharge, and therefore do not reflect meteorological effects. The predominance of ebb flow over flood flow will decrease with decreasing river discharge.

Within the estuary proper, the salinity decreases in a more or less uniform manner from the mouth toward the head, and at any location increases with depth. Superimposed upon the oscillatory tide, there is a net non-tidal circulation in which the upper, less saline layers of water move seaward, while the deeper, more saline layers of water move up the estuary. The net non-tidal seaward-directed flow is stronger and, in the vicinity of the site, extends to greater depths on the southern side of the estuary (looking downstream) than on the northern side. At times, the boundary between these two counterflows becomes strongly sloped so that the seaward flow extends to all depths on the south side of the estuary, and the flow directed up the estuary occurs from bottom to surface on the north side of the estuary.

The volume rate of flow associated with this net non-tidal circulation pattern, while small compared to the oscillatory tidal flows, is several-fold larger than the volume rate of river discharge. In general, the higher the salinity, the larger the ratio of the volume rate of seaward flow in the surface layers to the fresh water discharge. Consequently, since the salinity at any given location increases with decreasing river discharge, the volume rate of flow associated with the net non-tidal circulation does not decrease directly with respect to the river discharge.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.3-3 There are no known or planned river control structures on the James River. Several small impoundments on tributaries in the upper reaches of the River do exist; however, their size and location would preclude any effect or danger to the safety-related structures at the station.

2.3.1.2 Floods 2.3.1.2.1 James River Flooding The sources of flooding in the James River at the Surry site are flood discharges due to watershed runoff and surge due to severe storms.

As described in Reference 4, river discharge data for the period 1935 to 1993 have been collected, analyzed, and presented in Table 2.3-1. Statistical analysis of these data give the results shown in Table 2.3-2 (Reference 21). Flood discharges for the various recurrence intervals for the James River near Richmond, Virginia, are given in Table 2.3-3 (References 5 & 22). Similar data for the James River at the Surry site are given in Table 2.3-4 (References 6 & 23).

The peak flood discharge at Richmond, Virginia, during the period from 1935 to 1993 occurred in June 1972 due to the excessive rainfall during Hurricane Agnes. Flood levels reported for Richmond were 4 to 5 feet higher than those recorded during the previous flood of record.

However, due to the wide flood plain at the site, the rise above normal water levels was relatively minor even during this severe flood.

It is highly unlikely that the formation of ice on the James River would obstruct the flow and cause flooding, due to the salinity of the river below the site. Thus, ice flooding is precluded as a source of flooding at the site.

An analysis of the probable rise in mean water level at the site associated with the flood discharges indicates that even for a flood discharge recurrence interval of only once in 50 years, the water level at the site would rise no more than 1 foot above normal mean river level, if not accompanied by unusual meteorological tides.

2.3.1.2.2 Hurricane Flooding The site is located approximately 32 nautical miles upstream of the confluence of the James and York Rivers and approximately 40 nautical miles from the mouth of the Chesapeake Bay where it enters the Atlantic Ocean.

Table 2.3-5 shows the estimated tidal recurrence interval at Old Point Comfort, near the mouth of the James River. Based on a review of data compiled since 1971, there were no significant high-water levels due to storm surge in this area. The two most severe storms, Hurricane Agnes in 1972 and Hurricane David in 1979, had both been classified tropical storms by the time they reached Virginia. Neither of these two hurricanes produced a large storm surge at the Virginia coast. The highest water level recorded at Norfolk, Virginia, in 100 years of record occurred in August 1933 and reached 8.6 feet mean sea level (MSL).

Revision 52Updated Online 09/30/20 SPS UFSAR 2.3-4 The probable maximum hurricane (PMH) was chosen as the most severe meteorological event at the Surry site. The characteristics of a probable maximum hurricane at latitude 37 as shown in Reference 9, are:

Central pressure index 26.97 in. Hg Radius of maximum winds 35 nautical miles Forward speed of translation 22 knots Maximum wind speed 135.4 mph Open coast surge during the PMH was calculated at the entrance to the Chesapeake Bay using methods based on the Bathystropic Storm Tide theory as described in References 7 and 8.

Theoretically, the highest open coast stillwater level consists of five components:

1. The highest astronomical tide.

2. An initial rise to account for short period anomalies.

3. The rise due to atmospheric pressure reduction.

4. The surge generated by the wind component acting perpendicular to the ocean bottom contours.

5. The surge generated by the wind component acting parallel to the ocean bottom contours.

Actual computation of the open coast surge was accomplished using two digital computer programs. The first program utilizes functions of wind speed, wind vector, and radial distance along the design axis and the traverse to compute the onshore and alongshore wind stress components, the rise in water level due to atmospheric pressure reduction for each time period at the beginning and end of each reach, and the average wind stress coefficient for each reach. The second program utilizes the output from the first program and the offshore bottom profile to compute the onshore and alongshore components of the open coast surge. The isovel field for probable maximum hurricane winds is shown in Figure 2.3-1.

The input data for the first program are shown in Figures 2.3-2 through 2.3-4. The Van Dorn wind stress coefficient was increased by 10%. The bottom friction factor used in the second program was calculated using the following equation, taken from Reference 8:

-6 1.85 4.58 x 10 x W K = -----------------------------------------------

1.3 S

where:

W = shelf width, nautical miles S = shelf slope, minutes

Revision 52Updated Online 09/30/20 SPS UFSAR 2.3-5 For this case, the bottom friction factor was computed to be 0.00355.

The offshore bottom profile used in the second program is shown in Figure 2.3-5.

Table 2.3-6 lists components of the highest stillwater level at the open coast for the probable maximum hurricane. Once the open coast stillwater level was determined, the storm surge was routed through the Chesapeake Bay and up the James River to the power station using the methods presented in Reference 9.

The mathematical model presented in Reference 10 consists of the one-dimensional continuity and momentum equations applicable to variable area estuaries, embayments, or sea-level canals. The equations are solved simultaneously by means of an explicit finite-difference scheme to yield values of tidal elevation and flow along the longitudinal axis of the waterway. The model takes into account the effects of wind stress, river inflow, ocean tidal hydrography and non-conveyance river water storage.

The entire James River from the river mouth at Chesapeake Bay to the head of tide at Richmond, Virginia, was considered in the model. The first 75 miles of the river reach from the river mouth was divided into 25-mile segments. An adequate storage area was provided in the model to account for the total tidal area of the remaining upstream river reach.

The model was first calibrated and verified with mean tide and spring tide elevations along the James River based on Tide Tables and Nautical Charts published by the National Ocean Service (References 11 & 12, respectively). The Mannings roughness coefficients ranged from 0.018 to 0.033 for the river reaches depending on the depth and river bottom and overbank characteristics. Good agreements between the recorded tide levels and model results at various locations along the James River were found. The model was then used for storm surge routing by applying the open coast PMH storm surge hydrography at the river mouth. In addition, a conservative average wind speed of 91 mph along the PMH maximum wind axis covering the entire river reach was used to account for wind setup along the river.

The storm surge hydrography based on the mean sea level (MSL) datum at Surry Power Station and calculated in the manner described above, is shown in Figure 2.3-6. Also shown in the same figure is the wind speed versus time. For comparison purposes, the open coast storm surge which was transposed to the mouth of the James River without attenuation is shown in Figure 2.3-7. The PMH stillwater level at the Surry Station river intake is 22.7 feet (Reference 17)

MSL. This surge level will result in reduced flow rates, due to reduced differential level driving head, in the gravity flow service water system. This is discussed in Section 9.9.1.3.

The size, period, and length of waves impinging on the east end of the site associated with the probable maximum hurricane were calculated using methods in Reference 13. These same methods were used to calculate run-up on slopes and the emergency pump house.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.3-6 The maximum calculated wind speed acting over the 3-nautical-mile fetch affecting the station was 120.5 mph. The average depth of the fetch was 23 feet, plus the surge depth at the site, bringing the total depth to 46.6 feet.

Using Figure 1-28 and Equation 1-27 of Reference 13, these factors produced waves at the east end of the site with the following characteristics:

Wave height 9.7 ft Wave length 159.0 ft Period 5.6 sec Using Figure 3-12 of Reference 13, assuming an average slope of bank of 1V to 5H, runup at the site was 8.24 feet for smooth slopes and 3.60 feet for rubble slopes. Since the slopes consist of material between the roughness of smooth and rubble slopes, these values were averaged, yielding a runup on slopes at the site of 5.9 feet. Consequently, the maximum runup elevation is approximately 28.6 feet MSL (22.7 feet MSL stillwater level at the site, plus 5.9-foot runup).

The maximum wind speed at the site was assumed to be 120.5 mph from the east. With the wind oriented in this direction, there would be no wave runup on the west side of the site. Waves would be generated and move in a westerly direction, impinging on the opposite shore.

In order to postulate waves on the west side of the site, it was assumed that waves would reflect off the opposite river bank and return to the west side of the site unattenuated. Wave runup elevations calculated in this manner will exceed those that can be reasonably expected at the west side of the site.

The average fetch was calculated in the manner described in Section 1.233b, Reference 13, and was found to be 3.2 nautical miles. The average depth of the river to the west of the site is 12.0 feet. When the river depth is added to the surge, the total water depth on the west side of the site is approximately 35 feet.

Using the methods outlined in Reference 13 and the above-mentioned data, wind-generated wave runup elevation was calculated for the west side of the site. The generated waves, impinging on the shoreline near Jamestown Island, possessed the following characteristics:

Wave height 8.5 ft Wave length 171.0 ft Period 6.2 sec Assuming the shoreline around Jamestown Island approximates a smooth beach with a 10-degree slope, Reference 14 gives a reflection coefficient of 0.15 for wave H/L = 0.05. Trees and brush in the area will tend to further reduce this factor. Using this factor, the reflected wave

Revision 52Updated Online 09/30/20 SPS UFSAR 2.3-7 height was calculated to be 1.3 feet. The unattenuated reflection of these waves was applied to the shore line on the west side of the station site.

Using Figure 3-12 of Reference 13, assuming the slopes in the area of the station discharge are approximately 1V to 2H, runup of waves on the west side of the site was calculated to be 1.3 feet above stillwater level in the vicinity of the discharge channel. The rock groins extending into the river and the topography between the river and the station will tend to minimize this calculated runup.

Maximum runup elevation for the west side of the site is 24.0 feet MSL. Critical equipment in this area is protected against flooding to Elevation 26.5 feet. The station grade of 26.5 feet MSL will accommodate a runup above stillwater level of 3.5 feet. In order to generate reflected waves of this magnitude, the reflection coefficient would have to be on the order of 0.4.

As shown in Reference Drawings 1 and 2, the emergency service water pumping equipment is housed in a reinforced-concrete structure above the deck of the circulating water intake structure. The floor and walls of the emergency pump room are watertight. A procedure requires the pump room entrance door to have a seal plate installed to limit water ingress into the pump house as discussed below before the arrival of the PMH to prevent inundation. Wave runup on the front of the structure is estimated to be well below the roof elevation of the structure (33.5 feet),

therefore overtopping will not occur.

Breaking waves during the probable maximum hurricane could impinge on the superstructure of the emergency service water pump house, which is located on the deck of the intake structure. Using Minikins method, as outlined on page 255 of Reference 13, the total resultant wave thrust on the wall is calculated to be approximately 29.3 kips/linear foot (Reference 19) acting at Elevation 22.7 feet MSL. The highly reinforced wall of the emergency service water pump house can withstand this loading.

The possibility of the river level being depressed below the suction level of the emergency service water pumps is extremely remote. The storm required to cause such a condition probably would be of the same magnitude as the probable maximum hurricane, and oriented in such a way that velocity components are downriver instead of upriver. For this to occur, the storm center must pass north of the river, and thus considerable filling by the storm would occur. Measurements of the probable maximum hurricane wind field indicate that downriver wind components could exist for about 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , and these components would vary between zero and a maximum and back to zero during the period. Thus, it is safe to say that the suction of the pumps would not be exposed for more than 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months .

The emergency service water pump diesels are protected against flooding in the remotely possible event of a probable maximum hurricane.

The maximum stillwater level at the screen well is calculated to be Elevation 22.7 feet MSL. The sill of the pump room door and the air intake louver openings are located at

Revision 52Updated Online 09/30/20 SPS UFSAR 2.3-8 Elevation 21 ft. 2 in. MSL. The doors are equipped with removable seal plates which, when installed, limit water ingress into the ESW pump house such that continued emergency service water pump operation is not jeopardized through this pathway during the design basis hurricane.

The air intake louver openings are protected against flooding to Elevation 24 feet MSL by watertight wells on the inside walls of the pump house. The openings are on the side of the building away from the surge.

In the unlikely event of a hurricane of postulated probable-maximum-hurricane magnitude at the Surry Power Station, there is a possibility of waves being generated, in the fetch formed between the circulating water intake structure and the east bank of the intake canal, of sufficient height and proper direction to cause intermittent surging of water into the emergency service water pump house through the air intake louvers located on the front of the structure.

To limit a buildup of water in the emergency service water pump house that could jeopardize emergency service water diesel operation, the air intake louvers are equipped with exterior covers which, when installed, limit water ingress into the ESW pump house. The exterior covers on these louvers prevent surging water from overtopping the watertight wells.

For both ESW pump house doors and the intake louver openings, the corresponding seal plates and exterior covers are required to be installed whenever hurricane conditions exist, or are forecast to exist, which would require their use to preclude significant water ingress.

With the normal air intake louvers covered, air for operation of the diesel-driven emergency service water pumps would be provided through the dampers located in the top of the pump house structure. The position of these dampers under the exhaust hood precludes any significant water entry into the pump house from wave overtopping or runup on the structure.

The elevation of the exhaust centerline is 36 ft. 6 in. MSL. This is sufficiently above the mean sea level to prevent flooding. It is possible that occasional waves may cause splash and spray up the walls of the structure to Elevation 36.2 feet MSL. These would not affect the integrity of the screen well, as the roof is watertight and the exhaust outlet is at an elevation above all wave generated splash, spray or flow and is configured to prevent any rainwater flow into the exhaust in such an event.

A minimum freeboard of greater than 4 feet is maintained between the canal water surface and the berm at Elevation +36 during hurricane flooding of the river (see Section 10.3.4.2).

In order to determine the maximum wave runup at the west end of the high-level intake canal, the wind at the station site was directed along the length of the canal. The following values were used in calculating the maximum wave runup, as described in Reference 15:

Canal depth range 20 - 25 ft Wind speed 120.5 mph

Revision 52Updated Online 09/30/20 SPS UFSAR 2.3-9 Effective fetch 1500 ft The waves generated possessed the following characteristics:

Wave height 1.7 ft Wave length 41 ft Period 1.6 sec Using Figure 3-12 of Reference 15 and assuming a smooth canal liner sloping 1V to 1.5H, the wave runup was calculated (Reference 18) to be 4.0 feet.

Since a minimum freeboard of greater than 4 feet is maintained during a hurricane, no overtopping is anticipated, and there will be no effect on the station.

A list of maximum-probable-flood protection levels for Class I structures is contained in Table 2.3-7.

2.3.2 Ground-Water Hydrology The hydrologic boundaries of the site proper are the James River on the east and west, Hog Island Creek to the north, and Chippokes and Hunnicut Creeks about 1 mile to the south.

Precipitation data pertaining to the site are contained in Section 2.2. A water budget analysis indicates that, of the total precipitation, 37% runs off and the remaining 63% is lost through evapotranspiration. Low soil permeabilities preclude significant ground-water recharge from local precipitation.

The soils in the site area, as described in Section 2.4, consist of a series (50 to 80 feet thick) of lenticularly interbedded fine sands, clays, and silts. These clay and silt members are essentially impermeable, and the sand member showed field permeabilities on the order of 1 x 10-4 cm/sec.

Twenty shallow wells within a 3-mile radius of the site obtain small supplies of water for domestic purposes from these sands. The closest shallow well in use is located 1.6 miles south of Unit 1 and supplies domestic water to a private residence. There is an abandoned shallow well near the south property line.

The above deposits are underlain by 240 to 270 feet of tough impermeable clay containing only occasional and limited sand members. At a depth of about 320 feet below the surface, Eocene and older sediments are encountered. The sand members of these sediments are excellent aquifers; many domestic wells and some industrial wells in the area obtain water supplies from this source. In general, yields range from 15 to 50 gpm; however, a well 799 feet deep at Bacons Castle, about 5 miles to the south, yielded under test 940 gpm with only 20.25 feet of drawdown.

The closest offsite deep wells are located on the State Waterfowl Refuge, about 1 mile north of the site; and at Drewry Point, approximately 0.6 mile southwest. Both wells are approximately

Revision 52Updated Online 09/30/20 SPS UFSAR 2.3-10 340 feet deep and have a yield of about 35 gpm. The well at Drewry Point is not in full-time use, since it serves a vacation cottage.

In addition to the 340-foot deep well on the State Waterfowl Refuge, which existed prior to station construction, there are nine operating water wells on the site property, which were constructed to serve several purposes. These wells are about 400 feet deep and obtain water from the Late Cretaceous sediments. Three of these wells yield 200 gpm each and are for makeup and domestic uses at the station. A separate well with a 100-gpm pump supplies the Training Center.

The hydraulic gradient is north, east, and west toward the James River. Both the deep well at Drewry Point and the shallow well south of the site up-gradient from the site. The deep well on the State Waterfowl Refuge is down-gradient from the site; however, it is not affected by water flow from the site. Based on the results of borings, the general geology of the area and the location of the site, the coefficient of permeability of the soil mass in a horizontal direction is estimated to be several orders of magnitude greater than in the vertical direction. Water that does not enter the soil will move laterally to the east, north, or west and discharge to the James River.

There is no possibility of surface or near-surface water migrating downward to enter the aquifers in strata of Eocene or older ages which supply deep wells. The results of various ground-water hydrology studies indicate that no adverse effects will result to the water resources in the region because of the operation of the station.

The monitoring of various wells is incorporated in the environmental sampling program for the station. Water quality analyses at Surry Power Station Units 1 and 2 show a chloride concentration ranging from 33 to 49 ppm. In general, the quality of water from the lower aquifers is good except very near the coast or where the potentiometric levels have dropped significantly below MSL.

Due to the isolated location of the plant site (James River on the north, east, and west sides, and a game refuge on the south side), no substantial industrial or residential development is anticipated in the immediate vicinity of the plant site. Therefore, no additional demand of a substantial nature upon the ground-water supply is expected.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.3-11

2.3 REFERENCES

1. D. W. Pritchard and J. H. Carpenter, Hydrology of the James River Estuary with Emphasis Upon the Ten-Mile Segment Centered on Hog Point, Virginia, Virginia Electric and Power Company, 1966.

2. Virginia Electric and Power Company, Surry Power Station, Independent Spent Fuel Storage Installation, Safety Analysis Report, October 1982.

3. Tidal Current Tables - Atlantic Coast of North America, published yearly by U. S.

Department of Commerce, Coast & Geodetic Survey.

4. Virginia Electric and Power Company, Surry Power Station, Units 3 and 4, Preliminary Safety Analysis Report, 1973.

5. State Water Control Board, Commonwealth of Virginia, Flood Frequency Data for the James River Near Richmond, Virginia, Gauge No. 20375, 1935-1979.

6. Magnitude and Frequency of Floods in the United States, U. S. Geological Survey Water Supply Paper 1673.

7. C. L. Bretschneider and J. I. Collins, Prediction of Hurricane Surge, and Investigation for Corpus Christi Texas, and Vicinity, NESCO Technical Report No. SN-120, prepared by National Engineering Science Co. for U. S. Army Engineer District, Galveston, Texas, 1963.

8. George Marinos and Jerry W. Woodward, Estimation of Hurricane Surge Hydrographs, Journal of Waterways and Harbors Division, ASCE, Vol. 94, No. WW2, May 1968, pp. 189-215.

9. Hydrometeorological Branch, U.S. Weather Bureau, Hurricane, Atlantic and Gulf Coasts of the United States, Interim Report, HUR 7-97, May 1968.

10. .Committee on Tidal Hydraulics, U.S. Army Corps of Engineers, The Computation of Tides and Currents in Estuaries and Canals, Technical Bulletin No. 16, June 1973.

11. U.S. Department of Commerce, National Oceanic Atmospheric Administration, National Ocean Service, Tide Tables, East Coast of North and South America, Yearly Publication.

12. U.S. Department of Commerce, National Oceanic Atmospheric Administration, National Ocean Service, Nautical Charts, United States-East Coast, Virginia-Chesapeake Bay, N. 12222, Cape Charles to Norfolk Harbor; No. 12248, James River, Newport News to Jamestown Island; No. 12251, James River, Jordan Point to Richmond.

13. U.S. Army Coastal Engineering Research Center, U.S. Army Corps of Engineers, Shore Protection, Planning and Design, Technical Report No. 4, U.S. Government Printing Office, Washington D.C., 1966

14. John J. Healy, Wave Damping Effect on Beaches, Proceedings, Minnesota International Hydraulics Convention, Minneapolis, Minn., August 1953, pp. 213-220.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.3-12

15. U.S. Army Coastal Engineering Research Center, U.S. Army Corps of Engineers, Shore Protection Manual, Vol. 1. U. S. Government Printing Office, Washington, D. C., 1984.

16. Stone & Webster Engineering Corporation Calculation, Probable Maximum Hurricane Open Coastal Surge 1493780 ENV-1 Rev. 0.

17. Stone & Webster Engineering Corporation Calculation, Probable Maximum Stillwater Level at Surry Site 1493780 ENV-2 Rev. 0.

18. Stone & Webster Engineering Corporation Calculation, Intake Canal Wave Runup for Surry Power Station 1493780 ENV-3 Rev. 1f

19. Virginia Power Calculation, CE-1062, Rev. 0, Surry Power Station Intake Structure Emergency Service Water Pump House Wave Thrust.

20. Virginia Power Calculation, CE-1229, Rev. 0, Surry UFSAR Update Table 2.3-1.

21. Virginia Power Calculation, CE-1230, Rev. 0, Surry UFSAR Update Table 2.3-2.

22. Virginia Power Calculation, CE-1233, Rev. 0, Surry UFSAR Update Table 2.3-3.

23. Virginia Power Calculation, CE-1234, Rev. 0, Surry UFSAR Update Table 2.3-4.

24. Virginia Power Letter to the State Dept. of Health, Amendments to the Waterworks Operation Permit No. 3181800-Surry Power Station, April 12, 1989.

2.3 REFERENCE DRAWINGS The list of Station Drawings below is provided for information only. The referenced drawings are not part of the UFSAR. This is not intended to be a complete listing of all Station Drawings referenced from this section of the UFSAR. The contents of Station Drawings are controlled by station procedure.

Drawing Number Description

1. 11448-FM-55A Arrangement: Intake Structure, Sheet 1, Unit 1

2. 11448-FM-55B Arrangement: Intake Structure, Sheet 2, Unit 1

Revision 52Updated Online 09/30/20 Table 2.3-1 MEAN MONTHLY DISCHARGE IN CFS - JAMES RIVER AT STATION SITE FOR WATER YEARS 1935 THROUGH 1993 (I.E., OCTOBER 1934 THROUGH SEPTEMBER 1993)

Water Year Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Year (Avg) 1935 5191 5011 20,951 22,488 14,827 20,490 32,045 8304 7830 6402 5298 19,092 13,965 1936 3145 8324 10,336 39,778 25,806 34,620 20,767 6702 4671 2849 3154 2157 13,504 1937 5711 2765 9137 36,185 19,862 10,693 27,926 13,040 6674 5289 9281 10,836 13,331 1938 24,819 11,887 8764 12,364 9991 13,118 9179 6437 15,797 17,190 12,997 3581 12,217 1939 2914 4934 9071 8997 26,181 19,751 10,359 5953 4666 7200 9128 3005 9247 1940 3096 4911 9552 5544 18,319 9215 18,959 10,018 16,688 7203 34,397 7616 11,559 1941 3447 7722 7832 11,332 6491 9135 22,105 3919 3527 8708 1971 1258 6537 1942 857 1415 3828 4510 6329 9306 5227 13,840 8358 3896 15,167 4836 6501 SPS UFSAR 1943 18,256 7319 12,771 14,106 21,118 17,614 14,073 11,788 7860 6649 2073 1508 11,221 1944 1476 2971 2659 6547 10,068 25,264 14,366 9823 3221 2312 2972 18,310 8053 1945 7251 4645 9886 13,750 12,804 12,297 8909 10,432 4178 10,654 4616 12,058 9280 1946 4294 5330 14,988 19,225 18,498 13,666 10,892 19,707 8209 6974 3846 2744 10,676 1947 2890 3455 4224 17,046 6241 13,376 13,026 6250 5107 4614 2686 3883 70,821 1948 4804 14,763 6476 9311 21,776 21,299 25,582 14,626 7700 4667 12,522 3051 2124 1949 7967 17,880 14,608 26,306 19,211 16,643 17,181 15,402 8626 13,777 9774 6254 15,814 2.3-13 1950 4734 11,681 8509 7858 17,805 13,292 7655 15,339 8790 6295 3895 13,268 10,012

Table 2.3-1 (CONTINUED)

Revision 52Updated Online 09/30/20 MEAN MONTHLY DISCHARGE IN CFS - JAMES RIVER AT STATION SITE FOR WATER YEARS 1935 THROUGH 1993 (I.E., OCTOBER 1934 THROUGH SEPTEMBER 1993)

Water Year Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Year (Avg) 1951 5073 4841 17,373 7512 17,023 15,945 21,682 8258 13,726 5190 3246 2419 10,165 1952 1827 5862 14,255 20,225 19,364 26,060 18,012 14,376 4884 4090 5870 6439 11,760 1953 2759 10,568 8983 16,907 17,642 24,795 14,829 10,005 5264 2842 1753 1618 9785 1954 1480 2207 5868 9705 7580 15,852 10,258 10,487 4231 2631 1486 954 6066 1955 5197 6395 9880 8058 12,374 25,728 12,307 5252 4733 3335 20,886 4665 9996 1956 5551 3459 2867 2992 11,632 10,921 11,667 4617 4176 3175 2259 2260 5342 1957 4270 8815 7461 7928 22,606 16,307 18,739 6662 6310 2116 1591 5050 8872 1958 4659 8761 17,261 16,549 17,213 20,480 26,168 20,890 6557 4537 6597 2652 12,675 SPS UFSAR 1959 2897 2949 6019 9769 6379 8496 18,616 6081 7729 3543 3874 2791 6665 1960 10,816 9065 11,290 10,307 23,161 17,069 25,301 14,660 7471 2971 4371 6735 11,870 1961 3169 3113 3700 5533 21,475 16,639 19,391 14,579 10,072 4995 4776 4125 9194 1962 15,220 7049 20,882 19,484 15,443 32,186 22,042 9135 9339 6809 3324 2621 13,677 1963 2552 8733 5498 13,541 9076 31,513 6740 4762 4410 1690 1139 1037 7567 1964 1133 2662 4740 14,509 16,992 15,649 9580 5522 2179 2071 1421 1630 6437 1965 2874 3106 6777 11,066 18,268 18,779 11,588 6452 3123 2521 1492 1413 7223 1966 2116 1687 1592 2233 15,165 11,597 4677 9696 3184 911 1350 1857 4840 2.3-14

Table 2.3-1 (CONTINUED)

Revision 52Updated Online 09/30/20 MEAN MONTHLY DISCHARGE IN CFS - JAMES RIVER AT STATION SITE FOR WATER YEARS 1935 THROUGH 1993 (I.E., OCTOBER 1934 THROUGH SEPTEMBER 1993)

Water Year Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Year (Avg) 1967 8731 4397 6400 11,895 10,158 22,175 5977 8725 4058 2541 6881 2446 7866 1968 7454 2952 14,857 11,486 9179 14,602 6415 7101 6025 2268 1990 1091 6961 1969 2549 5139 3594 6928 8806 14,861 7618 5152 5021 8109 25,541 3777 8109 1970 7148 1048 7199 14,249 15,710 9501 14,915 7435 2309 2725 2497 1073 6986 1971 1211 11,674 6779 10,268 23,950 11,404 12,290 18,062 19,724 3884 4366 5001 10,847 1972 21,218 9641 10,143 9644 25,296 13,872 14,189 19,476 42,208 15,284 10,241 3302 16,122 1973 31,379 28,135 26,270 16,934 28,639 25,154 30,660 18,229 9386 5449 4663 2862 18,914 1974 4396 4849 25,001 21,648 13,928 14,235 15,124 11,421 7591 3878 5399 11,377 11,571 SPS UFSAR 1975 2950 3321 9275 14,299 17,886 37,302 14,026 13,600 7566 13,807 5482 18,647 13,167 1976 11,034 7970 7676 23,943 13,398 9778 10,079 6000 9883 3498 1952 1904 8906 1977 21,507 8370 12,969 6552 7013 12,975 14,004 4334 2561 1616 1551 1875 7965 1978 3931 13,338 15,576 35,849 10,739 29,959 17,050 26,456 7012 4766 7425 2963 14,670 1979 2130 3156 8154 25,377 28,869 30,398 16,499 12,407 17,220 5321 5011 27,492 15,047 1980 27,223 17,836 10,691 24,528 9677 24,845 27,621 12,085 5017 3642 2272 1450 13,952 1981 2287 3067 2803 2446 6621 4459 5649 6093 7611 3899 2661 2649 4161 1982 2978 3253 6193 10,953 23,617 19,796 8420 7071 19,569 5397 5263 2427 9475 2.3-15

Table 2.3-1 (CONTINUED)

Revision 52Updated Online 09/30/20 MEAN MONTHLY DISCHARGE IN CFS - JAMES RIVER AT STATION SITE FOR WATER YEARS 1935 THROUGH 1993 (I.E., OCTOBER 1934 THROUGH SEPTEMBER 1993)

Water Year Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Year (Avg) 1983 3655 4780 13,321 6437 17,617 23,284 39,090 12,839 6860 3184 1775 1347 11,109 1984 4052 8408 18,860 12,653 27,924 30,781 32,994 16,147 6121 6035 12,157 4214 14,946 1985 3942 5073 8255 10,421 17,192 8330 6063 7088 4334 2947 11,345 3322 7308 1986 4646 42,041 12,822 6284 13,115 13,406 6195 5899 2910 1989 3571 2271 9526 1987 1670 3556 13,438 12,579 16,775 19,215 45,304 11,285 5457 2943 1397 13,332 12,158 1988 3066 6226 11,336 11,742 9654 6812 7524 10,553 4085 3174 2068 2052 6516 1989 1936 4686 4291 5775 8427 17,365 13,029 30,818 10,774 10,784 6235 12,372 10,562 1990 15,579 10,745 6852 19,947 17,792 11,915 16,503 15,785 9875 3910 3528 2205 11,181 SPS UFSAR 1991 12,018 5537 9444 23,244 8575 20,720 15,237 6212 4234 6159 5106 1991 9918 1992 1879 2433 6320 8735 9355 15,890 16,694 9688 11,478 4087 3138 3244 7724 1993 2929 9352 11,782 18,211 12,877 45,418 28,277 10,497 6239 2848 2230 1695 12,709 Note: Total drainage area is 9517 square miles, of which 8395 square miles is gauged. Figures in this table include estimates of the runoff for the 1122 square miles of ungauged drainage area.

2.3-16

Revision 52Updated Online 09/30/20 SPS UFSAR 2.3-17 Table 2.3-2 DURATION DATA MONTHLY MEAN DISCHARGE - FRESH WATER JAMES RIVER AT SURRY POWER STATION (1935-1993)

Percent of Months Mean Discharge is Mean Discharge, cfs Equalled or Exceeded 857 100 2504 90 4089 75 7948 50 14,200 25 20,908 10 Mean of mean monthly discharges - 10,229 cfs Maximum mean monthly discharge - 45,418 cfs, March 1993.

Table 2.3-3 MAGNITUDE AND FREQUENCY OF FLOOD DISCHARGES ON THE JAMES RIVER NEAR RICHMOND, VIRGINIA (FOR THE PERIOD OF RECORD 1935 - 1993)

Recurrence Interval, years Discharge, cfs 1.1 38,820 2 75,500 5 121,900 10 159,000 25 213,500 50 260,000 100 311,600

Revision 52Updated Online 09/30/20 SPS UFSAR 2.3-18 Table 2.3-4 MAGNITUDE AND FREQUENCY OF FLOOD DISCHARGES AT STATION SITE Recurrence Interval, Ratio of Discharge Discharge, years to Mean Annual Flood cfs 1.1 0.43 47,100 2 0.85 93,300 5 1.36 150,000 10 1.77 195,000 25 2.36 260,000 50 2.85 313,000 100 3.39 373,000 Table 2.3-5 ESTIMATED TIDAL RECURRENCE INTERVAL AT OLD POINT COMFORT Recurrence Interval, years Maximum Tide Level, ft MSL 1 3.9 5 5.1 10 5.8 25 6.9 50 7.8 100 8.5

Revision 52Updated Online 09/30/20 SPS UFSAR 2.3-19 Table 2.3-6 COMPONENTS OF HIGHEST STILLWATER LEVEL (OPEN COAST)

FOR THE PROBABLE MAXIMUM HURRICANE Atmospheric pressure reduction 2.02 Alongshore component 1.86 Onshore component 15.62 Open coast surge (subtotal) 19.50 Astronomical tide 3.40 Initial rise 0.50 Open coast stillwater level above mean low water 23.40 Open coast stillwater level above mean sea level 22.20

Revision 52Updated Online 09/30/20 SPS UFSAR 2.3-20 Table 2.3-7 MAXIMUM-PROBABLE-FLOOD PROTECTION LEVELS FOR CLASS I STRUCTURES Flood Protection Level, Class I Structure ft - MSL Containment structure 26.5 Cable vault and cable tunnel 26.5 Pipe tunnel between containment and auxiliary building 26.5 Main steam and feedwater isolation valve cubicle 27.5 Recirculation spray and low-head safety injection pump 26.5 cubicle Safeguards ventilation room 26.5 Auxiliary building 26.5 Fuel building 26.5 Control room 27.0 Emergency switchgear and relay room 26.5 Relay room 26.5 Battery room 26.5 Air-conditioning equipment room 26.5 Reactor trip breaker cubicle 45.25 Emergency diesel-generator room 26.5 Circulating water intake structure (emergency service water 24.0 pump house)

High-level intake structure 36.0 Seal pit Not Applicable

Revision 52Updated Online 09/30/20 SPS UFSAR 2.3-21 Figure 2.3-1 ISOVEL FIELD PROBABLE MAXIMUM HURRICANE

Revision 52Updated Online 09/30/20 SPS UFSAR 2.3-22 Figure 2.3-2 PROBABLE MAXIMUM HURRICANE

Revision 52Updated Online 09/30/20 SPS UFSAR 2.3-23 Figure 2.3-3 PROBABLE MAXIMUM HURRICANE

Revision 52Updated Online 09/30/20 SPS UFSAR 2.3-24 Figure 2.3-4 PROBABLE MAXIMUM HURRICANE

Revision 52Updated Online 09/30/20 SPS UFSAR 2.3-25 Figure 2.3-5 OFFSHORE BOTTOM PROFILE FROM CENTERLINE OF CHESAPEAKE BAY -

SEAWARD ON COURSE S 63 E

Revision 52Updated Online 09/30/20 Figure 2.3-6 PMH SURGE AND WIND SPEED AT SURRY SITE SPS UFSAR 2.3-26

Revision 52Updated Online 09/30/20 Figure 2.3-7 TIME - HOURS AFTER PMH 0 ISOVEL PASSES JAMES RIVER MOUTH SURGE HYDROGRAPHS SPS UFSAR 2.3-27

Revision 52Updated Online 09/30/20 Figure 2.3-8 FACTORS FOR REDUCING HURRICANE WIND SPEEDS WHEN CENTER OVER LAND SPS UFSAR 2.3-28

Revision 52Updated Online 09/30/20 SPS UFSAR 2.3-29 Figure 2.3-9 SURGE HYDROGRAPHS

Revision 52Updated Online 09/30/20 SPS UFSAR 2.3-30 Intentionally Blank

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-1 2.4 GEOLOGY 2.4.1 Geologic Investigations Investigations of geologic foundation conditions at the Surry Power Station site have included the following:

1. Investigations and studies made under supervision of Dames & Moore, and reported on November 17, 1967 (Reference 1):

a. Study and report on regional and local geology.

b. Study of ground-water and surface hydrology.

c. Borings - total number 55, maximum depth 200 feet.

d. Laboratory tests of soil samples from borings to determine, under static and dynamic loads, shear strength, compressibility, permeability, and relative density of soils.

e. Refraction seismic surveys to measure primary and shear wave velocities in near-surface soils.

f. Micromotion studies.

2. Investigations and studies made under supervision of Stone & Webster Engineering Corporation:

a. Ten borings by Penniman & Brown in the immediate area of the turbine building and reactor containment structures.

b. In-place density tests of Sand A and Sand B as found during excavation of containment structure cofferdam.

c. Lateral load test of two piles under the fuel building (report dated July 1968).

d. Direct load test on seven piles (report dated June 28, 1967).

e. Taking undisturbed block samples of Pleistocene clays for further testing by Hardin, and by Goldberg and Zoino.

f. Installed system of piezometers to monitor ground-water levels in several aquifers.

3. Dr. R. V. Whitman, Report on Foundation Dynamics for Proposed Nuclear Power Plant, July 1967.

4. Dr. Boddy O. Hardin - Tests on undisturbed block samples of Pleistocene clays, and on a slightly disturbed sample of Miocene clay to determine static shearing strengths and shear

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-2 moduli for dynamic loadings (reported under dates of October 5, November 11, and December 1, 1967).

5. Goldberg and Zoino - October 18, 1967, and December 7, 1967, reports of tests on Pleistocene sands and undisturbed clays for determination of:

a. Relative densities for sands.

b. Consolidation characteristics of clays.

c. Quick shear strength of clays.

d. Shear strength characteristics of clays for triaxial tests with pore pressure measured, test type C. U.

Routine water samples have been taken from the James River in the area of the station where the river water is brackish. Basic sulfide and carbonate precipitation methods were used to analyze the water, instead of simply boiling the water to dryness and counting the residue. During mid-1968, a sample from Cobham Bay had a carbonate activity of 20 pCi/liter. This was greater than other samples taken from the river.

To investigate possible causes, the beaches along Cobham Bay were explored. There are numerous locations where the high banks along the river have been washed away, exposing outcroppings of the Yorktown formation which date from the Miocene Epoch (more than approximately 12 million years old). It seems wherever the outcroppings exist, a black, heavy, sand-like material is very abundant on the beaches, varying up to about 1-in. thick and several feet wide. Several samples of the black sand were taken and, in addition, numerous fossilized whale bones that were also found in the area were taken. Gamma spectral analysis by Vepco indicated a relatively high Thorium-232 content in the black sand, and a relatively high Uranium-238 content in the fossils.

In early 1969, a representative of Froehling and Robertson, Inc., of Richmond, Virginia, took six samples of the black sand and sent them to International Chemical and Nuclear Corporation for an analysis. The existence of Thorium-232 and its decay daughters was confirmed.

During the early part of 1969, a majority of the beaches along the James River were explored in an effort to determine the extent of the black sand deposits. Deposits were found scattered all along the southern shore of Cobham Bay. Locations were also found at outcroppings on Burwells Bay, south of Hog Island. In addition, deposits were found on the north shore of the James River, near Camp Wallace, which is northeast of the station site.

In June 1969, a representative of the Virginia State Radiation Health group was shown the deposits on Cobham Bay.

Since the sample of Cobham Bay water of 1968, other grab samples have varied from non-detectable limits up to 49 pCi/liter, with the majority below 10 pCi/liter.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-3 2.4.2 GeologySummary 2.4.2.1 Basic Geology East of the Blue Ridge Mountains, Virginia may be divided into two broad physiographic units, the Piedmont Province and the Coastal Plain Province.

The Piedmont is essentially a bedrock plateau. Surface deposits are primarily residual soils derived from weathering of underlying bedrocks, which are basically a complex of meta-sediments of pre-Cambrian and early Paleozoic age, with some areas of sedimentary and igneous rocks of Triassic age.

The boundary between the Piedmont and Coastal Plain Provinces, termed the Fall Line, extends from New Jersey to Alabama and passes through Richmond and Petersburg. Slow regional downwarping along the axis of the Fall Line began in early Cretaceous time, about 120 million years ago, and continued through Tertiary time.

South and east of the Fall Line, the Piedmont surface was depressed to a gentle downward slope until, at Cape Henry, it is about 2800 feet below sea level. This downwarped surface formed a base on which Cretaceous and later sediments have been deposited in a general wedge-shaped mass, with individual members also being wedge-shaped and thickening toward the southeast.

Based on regional data, these sediments are undeformed. They show no evidence of metamorphism and even the earliest are still essentially clays and sands. All available evidence indicates that, since early Cretaceous time, the crystalline basement beneath the Coastal Plain has been tectonically dormant. No faults are known or suspected at the site or in the vicinity of the site.

The Surry site is located on Gravel Neck, in Surry County, Virginia. The site is located in the Coastal Plain physiographic province approximately halfway between the Atlantic Ocean and the Fall Zone (see Figures 2.4-1 & 2.4-2).

In Virginia, the Coastal Plain has a stair-step character composed of a series of plains that are successively lower from west to east and are separated from one another by scarps. In the site vicinity, four plains are recognized. From the highest to the lowest they are the 120-foot plain, 90-foot plain, 70-foot plain, and 45-foot plain. Also, three prominent scarps are present. They are the Surry scarp, the Peary scarp, and the Chippokes scarp.

The surface of the Coastal Plain slopes gently in an east-to-southeast direction from about Elevation +200 at the Fall Line to sea level at the coast and thence out under the ocean. The slope is not uniform, but is characterized by essentially flat areas separated by gentle slopes of a few degrees, which are termed scarps. The average slope in the region of the site is about 1.5 ft/mile (Reference 4).

During the progressive downwarping of the crystalline basement of the Coastal Plain, various portions of the area were above, at, or below sea level, with alternating periods of marine

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-4 and continental deposition occurring. A columnar geologic sections for the site area are shown on Figures 2.4-3 and 2.4-4.

The morphologic boundaries of Gravel Neck are the James River on the west, north, and east sides, and the Chippokes scarp to the south. This scarp is about 5 miles long, lies in a southeast-northwest direction, is 45 to 50 feet in height, and has a surface sloping downward toward the northeast at about 3 degrees. The site area is flat and featureless with an average Elevation of about 30 feet above mean sea level (MSL). In the immediate site area, there are no surface features indicative of actual or potential localized subsidence of landsliding. There is no history of surface mining, withdrawal of large quantities of fluids such as petroleum, or other activity by man which would cause settlement or ground disturbance. Heavy vegetation covers most of the site.

In the site area, surface deposits are sediments of the Norfolk Estuarine Formation of Pleistocene age, extending to depths of about 50 to 80 feet. The upper 20 to 35 feet of the Norfolk Formation consists of layers of brown and mottled brown sand, silty sand, and organic and inorganic silts and clays. Interspersed are thin lenses of iron-oxide cemented sands. The lower part of the formation consists of layers of gray sand, silty sand, and organic and inorganic silts and clays, many of which contain decayed vegetation and shell fragments. These most probably were deposited under estuarine, lagoonal, and swamp conditions. The Norfolk formation was deposited upon an erosional surface of the Yorktown formation during the late-Pleistocene age when the sea level rose to approximately Elevation 45 feet. At the end of the Pleistocene age the sea receded.

Erosion of the Norfolk sediments is continuing today in the site area. It is accompanied by deposition of recent alluvial deposits in stream valleys, marshes, and lagoons.

The Norfolk Formation unconformably overlies the Chesapeake Group of Miocene age.

Upper Miocene, Pliocene, and early Pleistocene deposits that may have existed have been removed by erosion. Within the site area, the surface of the Miocene sediments, estimated to be 240 feet thick, are found at elevations varying from -16 to -47 MSL. Consolidation tests made on samples from the Miocene deposits showed them to be overconsolidated by 4 to 5 tons/ft2 in excess of existing overburden pressures. This suggests that from 150 feet to 200 feet of material previously lying above the present Miocene was removed by erosion before deposition of the Pleistocene deposits.

The Chesapeake Formation, of Miocene age, in the site area consists of compact, very stiff, tough clays, green to dark gray in color, with occasional compact sand and silt members. Shell fragments are common. These soils are strong and stable, with moderate to high shearing strengths. Underlying the Miocene sediments are Eocene, Paleocene, and Cretaceous sediments.

These are estimated to be about 45, 55, and 800 feet thick, respectively, based on wells drilled in the general area. From seismic investigations about 2 miles southeast of the site, crystalline bedrock is estimated to be at a depth of about 1300 feet.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-5 2.4.2.2 Geologic History Although the complex evolutionary history of the Appalachian Highlands and that of the Coastal Plain is not completely understood, investigations by numerous geologists allow the following account of the basic geologic history of the central Appalachian region. Table 2.4-1 summarizes the major orogenic events, lists their area of influence, and comments on the character of the event.

Precambrian Intense metamorphic deformation occurred in the Precambrian age from 1100 to 800 million years ago (Grenville orogeny). Sedimentary and igneous rocks were metamorphosed to form the metamorphic crystalline rocks now known as the basement. These basement rocks are exposed today in the Blue Ridge province and Baltimore gneiss domes.

The Grenville orogeny was followed by a period in late-Precambrian time characterized by subaerial erosion that apparently stripped away most superficial structures. This tectonically inactive period was followed by orogenic movements.

The Avalonian orogeny occurred in very late-Precambrian time, 580 to 600 million years ago. This period of deformation was marked by very large and thick accumulations of clastic sediment and volcanics accompanied, if not caused, by sharp local uplifts and downwarps. The nature of these uplifts, whether they were folds, fault blocks, or islands, remains obscure. This period of intense tectonic activity marks the beginning of the differentiation of the Appalachian region from the rest of North America.

Early-Paleozoic Era The Avalonian orogeny was followed by the subaqueous deposition of thick carbonate and mud sequences, with some volcanics at the end of Cambrian and start of Ordovician time. In middle-Ordovician time, about 450 to 500 million years ago, the thick sequence of late-Precambrian and early-Paleozoic sediments was metamorphosed, deformed, and intruded by intense igneous activity. This period of deformation was called the Taconic orogeny and was the most intense tectonic event of the central Appalachian region.

A second orogeny, known as the Acadian orogeny, occurred during the Paleozoic age, about 360 to 400 million years ago. It was accompanied by regional metamorphism and granitic intrusion. Although very intense in the northern Appalachians, its effect in the central Appalachians is not well established.

Late Paleozic Era While the Piedmont and Blue Ridge provinces were undergoing metamorphism and igneous intrusion during the early- and mid-Paleozoic ages, the Valley and Ridge and Appalachian Plateau provinces were receiving sediments. At the end of the Paleozoic era, about 230 to 260 million

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-6 years ago, the entire sedimentary sequence of the Valley and Ridge and Appalachian Plateau provinces were receiving sediments. At the end of the Paleozoic era, about 230 million years ago, the entire sedimentary sequence of the Valley and Ridge was folded and faulted producing the present mountainous terrain. This period of deformation is known as the Allegheny orogeny. It was long considered the main Appalachian orogeny; however, it is now evident that it was only one event at the end of a series of deformations throughout the Paleozoic. Its effect in the Piedmont and Coastal Plain must have been nominal. There is no evidence to date showing any marked tectonic activity in these provinces from the Appalachian events.

Early Mesozoic Era The late-Triassic period, 190 to 200 million years ago, marked the last orogenic episode of the Appalachian region. Large regional arching was accompanied by development of downfaulted basins which were contemporaneously filled with Triassic continental sediments and lava flows.

Accompanying the regional arching was the development of dike swarms. In the region of study, dikes trend mostly northwest which is transverse to regional structural trends. The dike activity may have lasted as late as the Jurassic period.

The eastern-most margin of the crystalline rocks of the Piedmont province was downwarped during Mesozoic time with accompanying uplift and arching of the western Piedmont and Blue Ridge provinces. The result was an accelerated erosion of the western areas and deposition of the eroded material on the downwarping eastern portion. Uplift and relative subsidence was most rapid during Cretaceous and Miocene times.

In the site area, the first sediments deposited on top of the crystalline bedrock were a mixture of terrestrial, deltaic, and shallow marine sediments of early-Cretaceous age. By late-Cretaceous time, a shallow sea covered the site area and stayed in the area until late-Miocene time. During this time interval, a thick sequence of marine sediments was deposited which are the Mattaponi, Aquia, Nanjemoy, Chickahominy, Calvert, St. Marys, and Yorktown formations.

The oldest unit encountered in the borings at the site is the Yorktown formation. Regionally it consists of a sand facies and silt-clay facies. The sand facies is the result of terrestrial stream deposits in a shallow marine environment. The silty and clayey sequences are the result of estuary and lagoon environments. In the borings at the site, only the silt-clay facies were encountered.

In late-Miocene and early-Pliocene time, 11 million years ago, the sea level receded which exposed the upper beds of the Yorktown formation to erosion. Extensive erosion occurred, followed by a period of deposition of the Sedley and Bacons Castle formation. They consist of Pliocene sediments of fluvial and estuarine origin.

During late-Pliocene and early-Pleistocene times, 2 million years ago, extensive erosion occurred which removed much, or in some places all, of the Bacons Castle and Sedley formations. Subsequently, the sea encroached on the land to about Elevation +100 and deposited estuarine and littoral (beach) sediments of the Windsor formation.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-7 During mid-Pleistocene time, the sea receded in stages leaving step-like plains and scarps at each intermediate stage. Erosion was extensive and in the site area all of the Windsor formation and parts of the Yorktown formation were removed. The present valley of the James River was established during this time.

In late-Pleistocene time, the sea level rose for the last time to about Elevation +45 accompanied by the deposition of clayey sands of the Norfolk formation in marshes and nearshore marine environments.

From the end of the Pleistocene time to the present, the sea has receded and the erosion of Norfolk sediments is continuing today in the site area. It is accompanied by deposition of recent alluvial deposits in stream valleys, marshes, and lagoons.

2.4.2.3 Structural Geology The site area lies on the southern flank of the Chesapeake-Delaware embayment, a depositional basin that has been downwarping and receiving sediments since late-Jurassic time, approximately 140 million years ago. Present regional subsidence in the site area has been measured to be about 1 to 5 mm per year (Reference 2). The resulting dip of the sedimentary units is oceanward, toward the east. The dip of the late Tertiary units (Yorktown) in the site area is 2 to 7 feet per mile, southeast (Reference 3).

For bedrock structural contours from the Cretaceous through the Pleistocene eras, no abrupt thickening nor asymmetric isopach contour patterns are present as would be expected for fault type subsidence (Reference 2). Rather, large gradually varying isopach patterns are evident. These may be formed by gradual regional downwarping, differential compaction, erosion or as a function of distance from the sediment source (deposition). The isopach centers vary in location with geological time and are not correlative with any localized structural effect.

Except for an area near Yorktown, Virginia, the site area and vicinity is devoid of any structural features indicative of folding or faulting. Southeast of Yorktown, Virginia, the beds of the Yorktown formation (Miocene age, 25 to 11 million years old) show a reversal of the regional dip. The beds dip 8 to 55 feet per mile, northwest. The reversal area was once believed to be of tectonic origin. However, as a result of more recent studies by Johnson, 1972 (Reference 3), the warping appears to be contemporaneous with Miocene deposition and the result of differential compaction of underlying units in response to surface loading. The northwest tilting had ceased prior to Pleistocene deposition, 2 million years ago. The overlying Pleistocene sediments show no dip reversal and conform with the regional trends.

In the immediate site area, surface inspection and subsurface investigations show no evidence of structural deformation. The borings indicate no offsets or folding of strata. There is no surface or subsurface evidence of prior landslides, cratering, or fissures that may be indicative of prior intense earthquake effects.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-8 2.4.3 Soil Conditions 2.4.3.1 General Original ground through the area of the station was at approximately Elevation +34, except for a few small shallow erosional depressions leading toward the river or north to the low marsh areas of the adjacent Hog Island Game Refuge.

Finished yard grade in the station area is Elevation +26.5. From ground surface to approximately Elevation -38 is a series of alternating strata of clay and sands of Pleistocene age.

These lie unconformably on Miocene clays that have in their upper portion a series of thin sand lenses. These thin Miocene sand lenses were found intermittently between about Elevations -55 and -62, and were individually only a few inches to a foot or so in thickness.

The locations of borings in the station area are shown in Figure 2.4-5. Detailed subsurface profiles along two mutually perpendicular axes, one through the reactor centerline of the containment structures, and the other on a line midway between the two units, are shown in Figures 2.4-6 and 2.4-7, respectively. For convenience in descriptions and studies, the sand members shown in Figures 2.4-6 and 2.4-7 at about Elevation -5 have been called Sand A, those at about Elevation -35, Sand B, and the thin sands at about Elevation -55 in the upper portion of the Miocene clays, Sand C. Sand A was present in its natural state during the period of geological investigation, but was replaced by backfill in selected areas prior to construction.

Additional information on 1982 borings conducted in the vicinity of the Surry site can be found in Reference 2.

2.4.3.2 Pleistocene Clays The Pleistocene clays are dark olive to dark gray, and of low to medium plasticity. Atterberg limits plot along or slightly above Casagrandes A Line, with liquid limits ranging from about 35% to 50%, and liquidity indices of about 30 to 40%. Quick shear strengths of these clays range from 1100 to 2900 lb/ft2. These were obtained in tests on undisturbed block samples taken during excavation of the cofferdams for the reactor containment structures. Sensitivity of these clays was about 3 to 6, when sensitivity is defined as the ratio of shearing strengths in the undisturbed state to those after complete remolding, with no change in moisture. Shear moduli as determined in cyclic torsional shear tests (Reference 4) were found to be about 12,000 psi to 14,000 psi, using undisturbed samples reconsolidated to appropriate vertical effective stresses. These values agree satisfactorily with Hardins proposed relations for computing shear moduli based on void ratio and effective stress. Damping in these tests was about 0.03 of critical at strains of about 2 x 105 radians. Consolidation tests on undisturbed samples showed preconsolidation of about 0.5 to 0.75 tons/ft2 in excess of existing overburden.

2.4.3.3 Pleistocene Sands Investigations of the Pleistocene sand made using borings during the initial site investigations (borings 7 through 44) were later supplemented by an additional series of borings

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-9 (45 through 50A), which were made after the station area had been excavated to about Elevation +7. A third group, designated by the suffix A or B, was then made adjoining and paralleling selected borings from the first two series. The purpose of this last series was to determine whether relatively low blow counts recorded for some of the samples taken in the sand were truly representative of conditions. Great care was taken with these last borings to ensure proper sampling techniques. The locations of all borings in the area of the structures are shown in Figure 2.4-5.

In the first series of borings, samples were taken using a 2.5-inch i.d. sampler, driven by a 300-lb weight falling 18 inches, or by hydraulic pull-down. In certain of the second series of borings, samples were taken alternatively with the above equipment and with a 1-3/8-inch i.d.

sampler driven by a 140-lb weight falling 30 inches, commonly referred to as the standard penetration test.

Plotting of the results of the driving resistances against each other for the second series of borings indicated that, for soil requiring 10 blows for 12-inch penetration in the standard penetration test, the 2.5-inch sampler required from 7 to 8 blows.

In situ densities and relative densities of sand members A and B were established by direct measurements and by study of penetration resistances in borings.

Profiles of the soils as determined during the excavation of the cofferdams are shown in Figures 2.4-6 and 2.4-7. The two significant sand strata, A and B, are considered individually.

Their density has been investigated by direct measurement of in situ density, as found in tests made as the cofferdams were excavated, and measurement of the density of undisturbed boring samples. The locations and elevations are shown in Figure 2.4-8. Shown also in this figure are locations where undisturbed block samples of the Pleistocene clays were recovered. Results of these in-place density tests are shown in Table 2.4-2, separated into Sand A and Sand B. In making these in situ tests, an attempt was made to select the cleaner sand members by visual examination. Despite this precaution, silty sands and some having significant dry strengths were included, especially in Sand B, which contained more silt and clay than did Sand A. Table 2.4-3 shows gradings for samples taken at 12-inch intervals vertically in Sand B between Elevations -26.5 and -36.5. It should be noted that only two of the samples were clean, and these were taken from a well-graded thin-gravel member.

Maximum densities obtained in the modified Proctor compaction tests by vibration were determined for comparison with the in situ density for each test. Minimum densities were determined for a number of the samples, which were sufficiently clean to make the minimum density test procedure valid. Relative densities are tabulated showing the values of in situ relative density, as compared with maximum density from both vibration and compaction. These data show Sand A in situ relative densities. Relative densities for Sand B were not established because of general excessive siltiness, which interfered with establishing minimum densities satisfactorily.

In situ densities for these materials, in general, ranged from about 100 to 110 lb/ft3, with one

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-10 sample showing an in-place density of 94.2 lb/ft3, equivalent to 88% of the maximum modified Proctor density for that soil.

Also shown in Table 2.4-2 are relative densities obtained by Dames & Moore from tests made on undisturbed samples of these soils. Undisturbed samples for this purpose were taken using the Dames & Moore thin-wall sampler, or with a Pitcher sampler forced down by hydraulic pressure. Their results are in close agreement with the in situ tests.

The soil within the cofferdams was excavated using a 3-yard clam shell bucket dropped freely. In both Sand A and Sand B, because of the projection of the wales, excavation by this equipment left an annulus of soil approximately 3 feet wide against the sheeting. This soil annulus stood intact with vertical faces of 12 to 16 feet in height until removed later.

Table 2.4-4 shows the blow counts for all samples in the upper sand from the borings. These are arranged in two groups, Group 1 being for the initial series of borings, and Group 2 for the second series of borings made within the area excavated to Elevation +7. The table also gives the amount of overburden for each sample above the elevation of the sample at the time the boring was made. A second column of N values headed Adjusted Blow Count is shown. In this column, the blow count for the 2.5-inch sampler has been increased by the ratio of 10:8 to correlate the results using this sampler with the standard penetration tests. Table 2.4-5 shows similar data for the lower sands.

As previously noted, supplementary borings, identified by the subscript A or B, were made adjacent to a number of the earlier borings that had shown relatively low blow counts, or N values. These supplementary borings were made about 3 feet from the original borings, under very careful supervision and sampling techniques to ensure results free of disturbance or error.

Accordingly, where supplementary borings were made, data from the initial borings were omitted as being questionable.

These data are shown graphically in Figure 2.4-9 for Sand A and in Figure 2.4-10 for Sand B. On these graphs are shown the fraction of occurrences of different values of blow count for the Group 1 borings and Group 2 borings. In Sand A, particularly, the difference between the two groups of borings is quite marked. The overburden effective stress at the level where these samples were taken was of the order of 3500 to 4000 lb/ft2.

After the area was excavated to Elevation +7, much less energy was required to drive the sampler, as indicated by the distribution of blow counts.

Relative densities of the sands from the penetration test results have been determined using the Average Curve of Gibbs and Holtz (Reference 5). These data, together with the relative densities as determined from the in situ tests and undisturbed samples, are plotted in Figure 2.4-11.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-11 These data indicate that Sand A is of variable density, ranging from sand of medium density, having a minimum relative density of about 65%, to very dense sands with relative densities in excess of 95%. Sand B is more uniform. The loosest members again are of medium density, about 65 to 70% relative density, or possibly slightly greater, with the majority of the sand in the dense condition at about 80% or greater relative density. Also, it should be noted that Sand B contains considerable silt and clay, and is thus less susceptible to liquefaction than clean sands would be.

2.4.3.4 Miocene Deposits Underlying Sand B is the Miocene clay. The contact is an unconformity, i.e., erosional surface, varying from about Elevation -34 to Elevation -40 in the station area. The Miocene clays are very stiff, and of a gray-green color. Boring 15, which was sampled continuously below Elevation -5, showed several thin sand members varying from a few inches to about a foot in thickness individually, and having a total thickness of about 4 or 5 feet below about Elevation -55.

These sand members have been termed Sand C. This is a glauconitic, clayey, silty sand. It was definitely identified only in Boring 15, but sandy members were noted at about the same elevation in several of the other borings. It is believed to be of limited lateral extent.

The Miocene clay is heavily overconsolidated. Preconsolidation pressures as determined in consolidation tests are plotted in Figure 2.4-12. These show overconsolidation of about 4 to 5 tons/ft2. Atterberg limits for this material plot somewhat above Casagrandes A Line in the region of low to medium plasticity. Quick shearing strengths are about 400 to 500 lb/ft2. Shear moduli, as determined from torsional shear tests on a reconsolidated boring sample that may have been slightly disturbed, are about 16,000 psi. This is somewhat below the value computed after Hardin. Internal damping as measured in the torsional test is about 0.03 of critical at strains of about 2 x 10-5 radians.

2.4.3.5 Site Settlement A site survey conducted in May 1975 indicated that site settlement was not a problem at the Surry Power Station (Reference 6). A follow-up survey program was continued over the next 2 years to further monitor site elevations. The results of the follow-up survey program are given in Table 2.4-6.

The follow-up survey program indicated that a small amount of heave had occurred in the vicinity of both containment structures; however, the differential movement between safety-related structures was below the allowable tolerance of 0.5 inches (0.042 feet). As shown by Table 2.4-6, the maximum differential movement had been about 0.2 inches (0.016 feet).

Inspection of structural interfaces showed no visible evidence of differential displacements.

2.4.4 Ground-Water Level As a portion of the original boring investigation, slotted plastic pipes were installed in a number of the borings to permit observations of ground-water levels in the area. These proved

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-12 unsatisfactory. Accordingly, in September 1967, Casagrande-type piezometers were installed at five locations, as shown in Figure 2.4-5. These piezometers were installed after the start of excavation for the containment structures, and drainage incident to the construction was considered in locating the piezometers.

As previously discussed, the boring program indicated two principal sand strata under the proposed structures. Also, there is a thin sand member near the top of the Miocene clays. The piezometer program was designed to measure the water table elevations in these three strata.

There are five groups of piezometers. Groups P1 and P2 each contain three piezometers, one in Sand A and two in Sand B, with one near the top and one near the bottom. Groups P3 and P4 each contain two piezometers, one in Sand B and one in the thin stratum at about Elevation -55 in the underlying Miocene clays, Sand C. Group P5 contains two piezometers, one each in Sand A and Sand B.

All piezometers are bedded in clean sand and installed in permanent casings. Bentonite seals extend from the sand embedment up into the casings. Approximate tip elevations were selected from data obtained from nearby borings. This was refined with preliminary borings at the locations selected for each group of piezometers, and the final tip elevation adjusted as necessary to place each piezometer in the sand stratum selected for study.

Readings of the piezometers began on September 26, 1967, after they had been installed for at least a week, which provided time for stabilization. These readings were made at hourly intervals for a 24-hour period in order to include two tide cycles. No response to tides could be detected within the limits of accuracy of the read-out, which is estimated to be +/-0.1 feet.

Thereafter, readings on the piezometers were made once a day until October 6, 1967, when the read-out interval was changed to once a week.

On October 4, 1967, all piezometers were flushed, and the rate of fall noted. The rate of fall indicated that all piezometers were in good communication with the soils in which they were set.

Read-out of piezometers was continued at a weekly interval until June 1968, approximately 8 months, and then placed on a weekly to biweekly interval until October 1968, completing a year of observations. No significant variations were noted during this period. The range of piezometric level in the piezometers remote from the station was only about 1 foot throughout this period of observation. The highest ground-water level observed during this period in Groups P1 and P2, which are remote from the excavation, were as follows:

1. Group P-1 Sand A +2.2 on September 26, 1968 Sand B +2.8 on February 8, 1968

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-13

2. Group P-2 Sand A +4.3 on February 1, 1968 Sand B +3.8 on February 8, 1968 The range of fluctuation, high to low, through this period of observations was approximately as follows:

P-1-A (Sand A) 1.9 feet P-1-C (Sand B) 2.0 feet P-2-A (Sand A) 1.5 feet P-2-C (Sand B) 1.6 feet Additional piezometer data from 1967 and 1971 are shown for comparison purposes in Table 2.4-7 and Figures 2.4-14 through 2.4-19. The consistency of the readings over this period indicates that each stratum behaves as a continuous aquifer, rather than as a series of isolated lenses. Possible interconnection between Sands A and B was not established, but may exist.

Should interconnection exist, communication should be small, since the vertical permeability of these sands is estimated to be about two orders of magnitude smaller than the horizontal permeability. Additional information on groundwater level at or near the Surry site can be found in References 7 and 8.

Moderate seepage occurred through the interlocks of the sheeting for the cofferdams for the containment structures. This drainage resulted in significant drawdown on the water table in Sands A and B at the cofferdam. In addition, six subsurface relief drains constructed with sand filters were provided into the Miocene clays under each containment structure. Two penetrate to Elevation -105, and four to Elevation -65. They discharge to the drainage system by means of a pervious layer provided under the containment structure. Seepage from Sand C through the cofferdam sheeting, and from under the structure, is collected in the sumps and removed by a system of permanent pumps. These pumps are set and controlled to maintain the water level around the containment structure at about Elevation -33 +/-2 feet. The annular space between the cofferdam and walls of the containment structure was backfilled with select granular material that is pervious. This pervious backfill rests on pervious concrete, and is thus connected to and drained by the drainage system.

It is assumed that Sand A is continuous to the discharge canal, and thus would be exposed to inflow from the canal during high water levels in the river. The maximum flood on record in the James River is 234,000 cfs. This corresponds to about the flow in the average spring tide cycle at the site. A flood of this magnitude would raise the river water level at the site about 1 foot above normal level. As the installed piezometers indicated no response to tides, no response would be expected to a 1-foot increase in river water level.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-14 The maximum recorded water level near the site was Elevation +7.7, which occurred as a hurricane surge in August 1933. Hurricane surges are of very short duration; the entire cycle from normal water level to maximum level to return to normal occurs in 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months or less.

The sharp gradient observed in the piezometric level in Sand A, proceeding away from the containment cofferdam observed during the construction period, indicates that short-duration exposure of Sand A to a high water level in the discharge canal would not affect the piezometric level in Sand A at the location of the structures because of the low permeability of the soils and the distance of the station site from the river and discharge canal.

Precipitation for the 12 months, September 1966 through August 1967, for several stations, is shown in Figure 2.4-20. It should be noted that total precipitation in this 12-month period was approximately equal to the mean precipitation for the area. Precipitation for the months of July and August was greater than normal, August having approximately double the recorded average for the month. Considering the geography of the site and the character of the near-surface deposits, it is reasonable to assume that precipitation in the immediate months preceding would have the greatest effect on water table conditions.

As indicated previously, the drainage system of the containment cofferdams is permanent.

Observations showed piezometric levels during construction of about Elevation -5 in Sand A, and about Elevation -10 in Sand B near the containment structure cofferdams. Values approximating these levels may be anticipated during operations. However, piezometric levels in these sands have been assumed at Elevation +5 in studies of liquefaction potential. This is above values recorded remote from the units and is considered conservative.

2.4.5 Liquefaction Potential 2.4.5.1 Summary Analyses of the potential for liquefaction of the sand underlying the Surry Power Station, based on piezometric data for the site, prove that liquefaction would not occur in any stratum for an earthquake having a maximum ground acceleration of 0.15g, the design-basis earthquake.

If the maximum earthquake acceleration were increased to a hypothetical value of 0.25g, the analyses indicate acceptable factors of safety against liquefaction, based on maintaining, in the future, present piezometric levels by means of the drainage provided. Even if it were assumed that drainage of Sand A or Sand B ceased to function and piezometric levels rose to a general site area value of Elevation +5, the analyses, which are based on conservative assumptions, give factors of safety greater than unity for the loosest zones found in either Sand A or Sand B. This would indicate that even momentary liquefaction will not occur in either sand. Since, however, Sand A immediately underlies the foundation mat of the auxiliary building and control area, where even local distortion might be significant, Sand A was removed from under the fuel building, auxiliary building, and control area, and replaced by dense-graded granular fill placed and compacted to such density equal to or exceeding 95% of that obtained in the Modified

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-15 Density Test-ASTM-1557-66. This effectively precludes any possibility of liquefaction in Sand A at any point under these structures. Since liquefaction of small pockets of Sand B could not result in any distortion of these auxiliary structures, Sand B was not replaced beneath the foundations of these structures.

The thin sand members in the upper portion of the Miocene deposits are permanently drained to the sump pumps exterior to the containment structure. This sand would not be subject to liquefaction under a hypothetical earthquake of 0.25g because of the weight of the overburden and the prevailing drainage, which results in depressed piezometric levels. The remaining strata are clays of types that are not subject to liquefaction.

Liquefaction will not occur at any location under yard areas adjacent to station structures, since the weight of the overburden is sufficient to preclude it.

2.4.5.2 Analysis Stratigraphy, soil properties, and piezometric data for the site have been discussed in detail in Sections 2.4.3 and 2.4.4. Seven dynamic triaxial tests have been performed upon samples of these sands at their in situ densities. In none of the tests was a sudden, complete liquefaction experienced; rather, once the applied cyclic shear loads were made large enough, there was only a gradual increase in strain during each cycle of loading. Such behavior is consistent with the in situ relative densities and with the large content of fines in the sands, especially in Sand B. This program of dynamic triaxial tests is discussed in Reference 9. The procedures followed in the analysis to determine the factor of safety against liquefaction are given in Reference 10.

As discussed in Section 2.4.4, piezometric levels under the structures will be depressed below the general area piezometric level of Elevation +5 because of permanent drainage facilities provided within the cofferdams of the containment structures. Analysis indicates that, under any of the several structures considered, the highest future piezometric pressure level in Sand B will be at or below about Elevation -7. In the unlikely event that these drainage systems ceased to function, ground-water levels could rise to the general area piezometer level of Elevation +5.0.

Analyses of liquefaction potential have been made for two different assumptions:

1. Ground-water level at Elevation -7.

2. Ground-water level at Elevation +5.

The factor of safety against liquefaction at any given depth within a soil can be estimated by comparing the average peak shear stress caused by an earthquake to the shear stresses required to cause liquefaction. The procedures used for estimating these two quantities have been verified by the experiences at Niigata and Anchorage.

Reference 11 presents curves used to establish the shear stress required to cause liquefaction. These curves were derived from tests upon a sand that is especially susceptible to liquefaction. Tests upon sands from Surry demonstrate that these curves give a conservative estimate for the resistance to liquefaction by the sands at Surry.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-16 Reference 12 describes the basis for estimating the shear stresses caused by an earthquake.

These estimates are based upon dynamic analyses giving the shear stresses developed near ground surface during actual earthquakes.

Typical calculations for safety factors are also presented in Reference 13. The safety factors presented are conservative, since:

1. A conservative (high) estimate has been used for the shear stresses caused by the assumed earthquake.

2. A conservative (high) estimate has been made for the number of cycles of motion during the assumed earthquake, thus leading to a conservative (low) estimate for the shear stress that will cause liquefaction.

3. The stresses required to cause liquefaction have been estimated using curves applicable to a sand (Sacramento River No. 3) that is especially susceptible to liquefaction. The characteristics of the sands at Surry indicate that they possess a greater resistance to liquefaction, especially Sand B, which is predominantly very silty, and, in places, clayey.

Factors of safety against liquefaction and cumulative strains of 5% for various structures and the several strata are tabulated in Reference 14 for 0.15g maximum ground acceleration, the design-basis earthquake, and in Tables 9.12D-l and 9.12D-2 of the FSAR (Reference 15) for an assumed hypothetical 0.25g ground acceleration.

The factor of safety against liquefaction of Sand A is of significance only for the yard areas, since this sand has been removed and replaced under the Class I structures. Analysis even for the hypothetical 0.25g acceleration shows an average factor of safety against initial liquefaction in the yard areas of 2.0 for Sand A for a ground-water table of Elevation +5. The factor of safety against the development of a cumulative strain of 5%, which may be used as a measure of the strain at which significant settlements may be expected to occur, would be about 2.1. Within isolated pockets, where the relative density may be only 60%, the safety factor against 5% strain would be about 1.6 for the conservative assumption of ground water at Elevation +5.0.

For Sand B, factors of safety at hypothetical 0.25g acceleration for average conditions at estimated future piezometer levels, considering drainage provided, would be about 1.8 under the auxiliary building for initial liquefaction, and 1.9 for 5% cumulative strain. If drainage were not considered, and a piezometric level of Elevation +5 was assumed, the values for average soil conditions for initial liquefaction would range from 1.4 under the auxiliary building to 1.8 under yard areas, and against 5% cumulative strain from 1.5 to 1.9.

Even if there were a few pockets where the relative density was only 60%, the safety factors against 5% strain would range from 1.2 to 1.5, based on the conservative assumption of a ground-water table at Elevation +5.

For Sand C, calculations indicate probable average factors of safety of about 1.9 against initial liquefaction, and 2.0 against a cumulative strain of 5% under the containment structure.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-17 These are based on observed piezometric levels, considering the permanent drainage system. If there were isolated pockets of sand having a relative density of 60% within this member, the factor of safety would be 1.5 against a cumulative strain of 5%.

As a further check on shearing stresses, a modal dynamic analysis was made of the entire soil column using recently developed procedures by Dr. Whitman (Reference 16). For this purpose the record of the El Centro earthquake, normalized to give maximum particle velocities at the surface of about 6 in/sec and 8 in/sec, was used as input at the rock surface. Input data were normalized to surface particle velocity, since velocity is often considered a better measure of intensity than acceleration. Various relations between velocity and intensity have been enumerated in Neuman (Reference 17) and Medvedev (Reference 18). All possible interpretations of intensity VII, according to these published relations, were used in selecting velocity and intensity values used in the modal dynamic analysis.

Computed ground motion and intensity values are given in Table 2.4-8. The results of the modal dynamic analysis are given in Table 2.4-9. These results verify that a ground acceleration of 0.15g and a ground velocity of 9.0 in/sec are conservative for the Surry design-basis earthquake, which has intensity VII.

Comparable shear stress values for the yard area were used in the analysis of liquefaction potential, as shown in Table 2.4-10. The analysis was based on a surface acceleration of 0.15g and on piezometric data given in Section 2.4.4. The analysis further demonstrates that indicated shearing stresses used in the calculations and shown in Tables S9.12D-l and S9.12D-2 of the PSAR are conservative.

Considering the conservative nature of the calculations, such results are taken to imply that no liquefaction will occur at this site.

2.4.6 Piling Unit loading under the turbine-generator foundation, the spent-fuel pit, the main steam shielding and safeguard area, and the refueling water storage tank are such that founding on the Pleistocene sediments would have resulted in undesirably large settlements. Accordingly, these structures are founded on piles. As an aid in selecting the pile type and appropriate loadings to be used, a series of seven piles of two different types and different lengths were driven and load-tested. A report on this test pile program is given in Reference 19. Onsite test pile data are also contained in Reference 20.

Based on the results of these tests, and considering structural arrangements and loadings, it was decided to use open-end steel pipe piles with an outside diameter of 12.75 inches by 5/16 wall thickness. Piles are driven into and derive their support from the overconsolidated Miocene clays. Tip grades for all piles are Elevation -70. To minimize disturbances of the Pleistocene clays, and to avoid lateral displacements of the soil and of structures on or buried in the soil due to driving the piles, a hole of 12-inch nominal diameter was prebored for each pile to Elevation -40.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-18 Each pile was then cleaned out to Elevation -40 and the upper portion filled with concrete with a 28-day strength of 4000 psi.

Total lateral deflection of any given structure under dynamic loadings for clearance between structures and for design of piping, etc., is taken as the sum of shear deflections of the soil plus deflections of the piles relative to the soil. Lateral deflections of piles relative to the soil were computed using programs for lateral deflection of piles developed by Stone & Webster.

To verify these deflections, two piles driven under the spent-fuel pit were loaded laterally to shears associated with the operating-basis earthquake and the design-basis earthquake.

Test results were in excellent agreement with computed values. A report of this test is discussed in Reference 20. Stresses under vertical and lateral loadings are within normal working loads for these materials.

Allowable pile loadings for vertical loads are given in Table 2.4-11. Lateral loads are also given in Table 2.4-11. These loadings are conservative, as indicated by the results of the load tests conducted.

2.4.7 Foundation Design A summary tabulation of the type of foundation under each of the principal plant structures is given in Table 2.4-12.

2.4.7.1 Reactor Containment The reactor containment structures are founded directly on the highly preconsolidated Miocene clays, using 10-foot-thick reinforced-concrete mats. Founding grade is Elevation -41. A drainage layer consisting of 12 inches of compacted granular fill was placed directly on the clays.

The six drains under the reactor containment (Section 2.4.4) connect with and drain to this drainage layer. This layer in turn connects with and is drained by a system of permanent sumps that maintain the water level in the annulus between the cofferdam and the reactor containment structure at about Elevation -33+/-2 feet.

To construct the containment structures, the general area was excavated from original ground surface, approximately Elevation +34, to Elevation +26.5. An area encompassing the entire power station, that is, from south of the south wall of the turbine room to about 35 feet north of the north side of the containment structures, was excavated to about Elevation +7. Local excavation was then performed as necessary to reach founding grades of the various structures.

For the containment structures, this was done using two circular cofferdams consisting of steel sheet piling driven to tip grade Elevation -48. Each cofferdam is 150 feet in diameter. The sheeting was supported by reinforced-concrete ring wales. The annular space between the cofferdam and the structure is filled with porous concrete from Elevation -41 to Elevation -21.6, and above this level with carefully compacted granular fill. Both are pervious and connect with

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-19 and form a portion of the drainage system around the structure. The granular fill is blanketed with 2 feet of impervious material near the top of the cofferdam to exclude water from above.

A detailed analysis of the settlement of the containment structures, including effects of heave or rebound, which is an upward movement that usually occurs in the soils under excavations as an elastic response to the removal of the weight of the soil, is presented in Reference 18. Computations of rebound for the containment structures indicated a total rebound of about 0.21 feet, of which 0.09 feet was from excavation from Elevation +26 to Elevation +7, and 0.12 feet. from excavation within the cofferdams. Four reference points for measuring heave were installed at Elevation -41 within each cofferdam before starting excavation. Observation showed good agreement between predicted and observed rebounds. Rebounds for excavation from Elevation +7 to Elevation -41 near the center of each cofferdam after completion of excavation were measured at 0.12 feet in the cofferdam for Unit 1, and 0.15 feet in the cofferdam for Unit 2. This compares with the prediction of 0.12 feet. Rebound is largely an elastic response, and is recovered quickly as load is reapplied by construction.

Deadweight load of the containment structure is approximately 7300 lb/ft 2 , and is symmetrical. The actual weight of soil removed in excavating to Elevation -41 is about 8600 lb/ft2. However, the drainage provided under these structures results in an increase in effective stresses in the underlying soil. When these factors are evaluated, a small net increase in effective stress in the soil of about 0.75 tons/ft 2 in excess of that which existed before construction is indicated, assuming the drainage to be fully effective. This is discussed in detail in Reference 21. This net added load is small compared with the overconsolidation of 4 to 5 tons/ft2 in excess of effective stresses in these soils before start of excavation. Long-term settlements from this net loading are estimated to be less than 0.5 inch. Settlements of approximately the same magnitude are estimated for adjoining structures. Thus differential settlement between the containment structure and adjoining structures will be small.

Under the design-basis earthquake contact, the pressure under the containment is increased to 10,000 lb/ft2. Since the founding level is 66 feet below surrounding grade, the effective stress in the soil adjoining is approximately 6950 lb/ft2 considering drawdown of piezometric levels.

Shearing strength of the Miocene clays is about 4500 lb/ft2, and in the overlying Pleisocene clays about 1100 to 2900 lb/ft2, 1500 lb/ft2 being a conservative value for use as an average. The factor of safety against shear failure under the edge of the mat is in excess of 3.0, based on Terzaghis procedure for computing bearing values for shallow foundations. This approach is conservative, since it is based on a load over the entire foundation area, whereas for the rocking mode under the design-basis earthquake the highest contact pressure occurs only under a limited portion near the edge of the foundation.

Additional settlement under these earthquake-induced loadings will be negligible, since they are well within the preconsolidation of the clay, and, further, are of such short duration that no consolidation can occur.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-20 2.4.7.2 Spent-Fuel Building Foundations for this structure consist of a continuous reinforced-concrete mat at Elevation 0 ft. 10 in., which is in turn supported on pipe piles into the Miocene clays with tip grades at Elevation -70. For a complete discussion of loadings on the piles, see Section 2.4.6.

Sand A was excavated from beneath this structure and replaced with dense, select, granular fill.

Estimated long-term settlements of this structure will be on the order of 0.5 inches.

2.4.7.3 Auxiliary Building and Control Area These structures are founded on continuous reinforced-concrete mat foundations at Elevation -2. The mats were placed on dense, select, granular fills that replaced Sand A.

The deadload weights of these structures are less than the weight of soil removed. Soil loadings are, therefore, appreciably less than preconsolidation loadings of the Pleistocene deposits remaining. There will be small elastic settlement as loads are applied, and long-term settlements will be less than 0.5 inches. Average bearing weights are about 2.2 to 2.5 kips/ft2.

Factors of safety against edge failure exceed 3.0.

2.4.7.4 Turbine Room The turbine generators are founded on continuous reinforced-concrete mats supported by open-ended pipe piles driven to tip grades of Elevation -70. These units average about 5000 lb/ft2 load over the area of the mats. Estimated long-term settlements will be on the order of 0.5 inches.

The remainder of the structure is isolated from the turbine-generator foundation, and is founded on a system of continuous-strip spread footings, except for some internal columns, which are founded on spread footings. Net founding contact pressures were kept at or below 2 tons/ft2 at Elevation +4. Where foundations were carried deeper, contact pressures were increased at the rate of 120 lb/ft2 per foot of depth below Elevation +4.0. This recognizes the increase in bearing value allowable as footing depth below surrounding grade is increased. Bearing values are conservative, and were established considering shear strength and preconsolidation of the Pleistocene clays.

The average load of this structure is less than half the weight of soil removed. Accordingly, long-term settlements will be small.

2.4.7.5 Miscellaneous Yard Structures The excavation for the station is backfilled to yard grade with dense, compacted granular fill. Miscellaneous small structures such as pipe enclosures, tanks, etc., are founded on or in this structural fill.

2.4.7.6 Screen Well The river intake structure is founded on fine, clean Pleistocene sands with some interbedded clays at Elevation -27. Foundation is a reinforced-concrete mat.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-21 The area was investigated by borings 51 through 55. These sands are quite dense, with N values in the Pleistocene formations ranging from 23 to 115. The median N value for samples from the five borings is 45 blows per foot.

Considering their density, there is no possibility of liquefaction under this structure.

The river intake structure was constructed within a steel sheet pile cofferdam, and the sheeting anchored to the structure and left in place. Tip grade of the sheeting is Elevation -51.

Since the area behind the screenwell is at Elevation +11, and in front is dredged to Elevation -27, it is subject to imbalanced lateral earth loads. Its stability was analyzed and found to be satisfactory; values were as follows:

1. General slide failure through dike of intake canal:

a. Static FS = 2.24

b. For DBE FS = 1.53

2. Friction factors coefficient-of-sliding at foundation level (passive pressure from sheeting not considered):

a. Static (one cell empty) 0.4

b. DBE (operating condition) 0.4 2.4.8 Relative Earthquake Displacements Considering the varying types of foundations used, determination of relative motion or displacements between the several structures for design of piping and rattle space was necessary.

In these analyses, displacements due to vibration and to ground movement during earthquake have been considered as follows:

1. Translation, both horizontal and vertical, and rotation of the building relative to the static position of the soil-structure interface.

2. In addition, for the auxiliary building and fuel building, lateral deflection from shear of a column of soil extending from Elevation -40 to founding grade, in accordance with the procedures outlined in a report by Dr. R. V. Whitman (Reference 22).

3. For pile-supported structures, deflection of the piles relative to the soil in which they are embedded.

4. Flexure and shear distortions of the several structures in estimating movements above the founding grades.

Vertical motions are given at the exterior of each structure. These motions include vertical translation and vertical motion of the exterior of the structure due to rocking assumed to be coincident with the vertical translation.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-22 For the containment structure, values shown are the root mean square of the sum of the displacement for four modes of vibration, using a model with four degrees of freedom. For other structures, displacements for the fundamental periods were used, since these are relatively low, simple structures. Values of various elevations for the several structures are tabulated in Table 2.4-13.

Displacements of the piles relative to the ground were computed using a computer program developed for laterally-loaded piles and using values of the coefficient of subgrade reaction based upon physical properties of the several soil strata. Computed deflections for the 12.75-inch-diameter concrete-filled pipe piles are shown on Table 2.4-14.

To verify these displacements, a cyclic lateral load test was made on two piles located in the compacted fill area under the fuel building where Sand A was removed. These tests are discussed in Section 2.4.6. Computed and test deflections were in good agreement.

Maximum relative motions between structures were computed as the sum of the vibratory displacements of both structures at a given elevation, plus relative ground motion from Figure 2.4-21. The values so obtained are considered to be extremely conservative. They assume relative motions of the several structures to be perfectly opposed and coincident with simultaneous maximum earthquake motion displacement of appropriate direction.

To allow for these relative motions between structures, the following is provided:

1. A space of 6 inches is provided between the pile-supported fuel building and the auxiliary building, and between the fuel building and the containment structures. For other structures, the clearance is 3 inches. Intrusion of foreign material into these clearance spaces is prevented by compressible filler material.

2. Maximum relative motion between adjoining structures is included in the stress analyses of all piping that must extend from one building to another.

Adequate slack was left in electrical cables.

In addition to the movements resulting from structural vibration, there will be movements of the structures relative to each other, resulting from ground displacements from orbital earthquake motion. These have been estimated from the ground movement spectrum at periods corresponding to one-half wave length for the type of motion considered; that is, shear in the horizontal and vertical planes, and compression-rarefaction for push-pull motion, with relative motion taken as twice the spectral displacement.

Vertical motion has been assumed as two-thirds of the horizontal. These data are shown on Figure 2.4-21. This figure provides quantitative values for that portion of relative displacements between structures that is due to orbital particle motion under earthquake excitation. The relative displacement due to orbital motion is assumed to be twice the maximum single amplitude of ground displacement for a wavelength equal to twice the distance between the centroids of the

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-23 structures considered. Periods are computed from these wavelengths using primary and shear wave velocities as appropriate to the orientation or relative motion and for the soil at about founding elevation. Using these periods, the amplitudes of displacement can then be computed for maximum ground acceleration and velocity.

2.4.9 Slope and Bank Stability The site is essentially flat, except immediately at the river banks and along the north property line, where it slopes gently down to the lowlands of the game preserve. The nearest river bank is approximately 1800 feet west of the station, where the banks are about 5 feet to 25 feet high above the beach. The beach has very gentle slopes, and the river bottom offshore is nearly flat, reaching 6-foot depth about 1000 feet offshore.

The station is about 8800 feet west of the bank along the east side of the peninsula, and about 1800 feet south of the north property line. Prior to excavation, the ground surface in the station site area was generally level at about Elevation +34, except for a minor erosional channel with gentle side slopes which entered the area from the west. Adjacent to the station, the bottom of this depression was at about Elevation +24. The discharge canal follows this depression, to minimize excavation and disturbance of vegetation.

The site was excavated to a generally level grade at Elevation +26.5. Temporary excavation for the buildings and containment structures was made to about Elevation +7. After completion of construction, the area was backfilled with compacted soils to Elevation +26.5.

The discharge canal lies to the north of the station. Its centerline is approximately 380 feet from the centerline of the containment structures, and about 350 feet from the north wall of the fuel building. The cross section of the discharge canal and its relation to the station is shown in Figure 2.4-22.

The river banks and the open channel sections of the discharge canal are sufficiently distant from the station that these free-sloping surfaces will not affect the dynamic shear stresses at the station resulting from earthquake motions.

Along the river front, rather steep banks have developed because of the undercutting during heavy storm wave conditions; however, these banks are otherwise stable. Local slumping might develop under heavy earthquake conditions, but migration of such disturbance back to the station, a distance of about 1800 feet, could not occur. As indicated in Section 2.4.5, the sands underlying the site are not subject to liquefaction, and a flow slide could not develop in them.

The banks of the discharge canal at Surry have been investigated for stability. They have a factor of safety under static conditions of about 2.0.

Analyses of the stability of these banks under earthquake conditions have been made, following the basic concepts outlined by Newmark (Reference 23). In these studies, effects of increased pore pressure in the sand members under earthquake conditions have been considered.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-24 Slide analyses have been considered for two different modes of failure: a rotational slide in a perpendicular vertical plane, where it was assumed that the lower sands had adequate friction to establish the slip plane in the medium clays at about Elevation -20 to -25; and a block slide analysis in which it was assumed that failure would develop in the lower sands because of excess pore pressures developed in these members under earthquake vibration. Tests on these sands have shown that a significant number of cycles of loading are required between the cycle when pore pressures first became equal to the overburden stresses, and the cycle when cumulative strains reach 5%.

A conservative value for the residual strength was used for the first mode of analysis by assuming zero shear strength in the sand members; that is, pore pressures in these sands were assumed to be equal to the overburden pressures along the plane of shear, although this condition holds only for a portion of the time in each pulse. N/A for these assumptions was about 1.8 for an assumed earthquake of 0.5g horizontal and 0.10g vertical acting simultaneously, indicating an adequate factor of safety and no distortion of the bank for this mode.

N/A is the ratio of acceleration applied as a static force that the bank could withstand to the maximum single-pulse ground acceleration.

For analysis of the second mode, excess pore pressures developing in about 12 cycles of loading for varying ratios of /v (where is shear stress and v is vertical effective stress in soil mass) were determined from the results of the dynamic triaxial tests. Approximate shearing stresses and effective stresses were then evaluated at various points along the assumed plane of shear. From these data, excess pore pressures under dynamic loadings were determined. Since the excess pore pressures, as shown by the test results, ranged from a maximum to a minimum value in each cycle of loading, the mean value in each cycle was used in evaluating the excess pore pressure. These were then added to initial static-state pore pressure, assuming a 5-foot drawdown of the piezometric surface near the discharge canal to permit evaluating residual shearing strengths in the soil mass at various points under the slide block.

N was then determined from the ratio of the total residual shear strength to the total mass in the sliding block.

This analysis is conservative because of several factors. Excess pore pressures are zero at the start of earthquake motion, and several cycles of such motion are required, especially when the overburden effective stresses are high, before excess pore pressure becomes significant.

Therefore, there could be only a few cycles of motion, rather than the 12 used where the residual shearing strength would be of the minimal values assumed. It is assumed that the excess pore pressure peaks coincide with the peak of velocity in the sliding mass. The test data from which the pore pressure was established were conservative, since initial pore pressures that may have existed at the beginning of each series of loading cycles at a given stress level were ignored in plotting the values of /v.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-25 N/A values on this method of analysis were in excess of 0.5 for an earthquake having a horizontal acceleration of 0.15g and vertical acceleration of 0.10g.

These studies, therefore, indicate that for the design-basis earthquake at 0.15g horizontal earthquake acceleration, there would be no significant slides or movements of the discharge canal banks.

Stability analyses made of the banks of the intake canal, based on the assumption that a combined horizontal ground motion of 0.15g and vertical ground motion of 0.10g would act simultaneously to produce maximum shearing stresses, indicated a factor of safety of 1.5 corresponding to Newmarks N/A of approximately 2.0, which indicates no displacement.

Analysis was by the method of slices and assumed no loss of shear strength in sand members. If it is assumed that sand members suffered a complete loss of shear strength because of increased pore pressures under vibratory loadings, the factor of safety is reduced to 1.34. These values indicate the banks of the intake canal would be stable under earthquake conditions.

The intake canal is lined with mesh-reinforced concrete for its entire length. Since such a lining could be cracked or otherwise damaged in the event of earthquakes, an analysis was made of the rate of seepage loss. In this study, it was assumed the lining did not exist. The study was based on tests of permeability made during site investigations, described by Dames & Moore in Revised Report - Environmental Studies, Proposed Nuclear Power Plant, Surry, Virginia, November 17, 1967, and showed that seepage loss from the canal would be insignificant with respect to the volume of water stored. Further, the emergency service water pumps are sized with adequate margins to accommodate expected leakage from the canal. Therefore, the net loss of water from the canal, even in the event of severe damage to the lining, would be zero.

Because of the large depth and generous freeboard of the intake canal, as described in Section 10.3.4.2, settlement developing from an earthquake would not interfere with the effectiveness of the canal in providing emergency cooling.

No information was obtained after construction of the canal that would necessitate alteration of the analysis of the potential for settlement of, leakage from, or stability of the intake canal.

The estimated seepage rate from the intake canal is 40 gpm. The seepage rate can also be stated as. 00476% of the circulating water flow in the canal, with one unit operating. With two units operating, the percentage is halved. The quoted seepage rate of 40 gpm could vary by a factor of 20 or more without adversely affecting the safe-shutdown requirements for the plant.

The 40 gpm represents 0.027% of the minimum capacity of one service water pump. More detailed information on the service water system is contained in Section 9.9.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-26

2.4 REFERENCES

1. Dames & Moore, Revised Report - Environmental Studies, Proposed Nuclear Power Plant, Surry Virginia, November 17, 1967.

2. B. K. Meade, Report of the Subcommission on Recent Crustal Movements in North America, Paper presented at XV General Assembly of IUGG, International Association Geology, Moscow, USSR, August 2-14, 1971, NOS, NOAA, 1971.

3. G. H. Johnson, Geology of the Yorktown, Poquoson West, and Poquosa East Quadrangles, Report of Investigations 30, Virginia Division of Mineral Resources, 1972.

4. Surry PSAR, Supplement, pp. S9.12A-l to -8.

5. H. J. Gibbs and W. G. Holtz, Research on Determining the Density of Sands by Spoon Penetration Testing, Fourth International Conference on Soil Mechanics and Foundation Engineering, Vol. I, Butterworth, London, 1957.

6. Letter from C. M. Stallings, Vepco, to K. R. Goller, NRC,

Subject:

Differential Settlement Survey of May 1975, dated July 23, 1975, Ser. No. 541.

7. Virginia Electric and Power Company, Surry Power Station, Units 3 and 4, Preliminary Safety Evaluation Report, 1973.

8. Virginia Electric and Power Company, Surry Power Station, Independent Spent Fuel Storage Installation, Safety Analysis Report, October 1982.

9. Surry PSAR, Supplement, pp. S9.12C-l to -5, Table 9.12C-l, and Figure S9.12C-1.

10. Surry PSAR, Supplement, pp. S9.12D-l to -6 and Figures S9.12D-1, -2, and -3.

11. Surry PSAR, Supplement, pp. S9.12C-l to -5, and Figure S9.12C-1.

12. Surry PSAR, Supplement, Section S9.12A.

13. Surry PSAR, Supplement, Section S9.12D.

14. Surry PSAR, Supplement, p. S9.12D-4, Table S9.12D-l.

15. Surry PSAR, Supplement, Section S9.12D.

16. R. V. Whitman and J. M. Roesset, Theoretical Background for Amplification Studies, MIT Research Report, R69-15, March 1969.

17. F. Neuman, Earthquake Intensity and Related Ground Motion, University of Washington Press, Seattle, 1954.

18. S. V. Medvedev, Deformation and Strain in Foundations of Structures from Strong Earthquakes, in Problems in Engineering Seismology, No. 8, Akad. Nauk SSSR Inst. Fiziki Zemli Trudy, Vol. 28, Table 5.

19. Stone & Webster Corporation, Test Pile Program, Surry Power Station, July 1968.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-27

20. Stone & Webster Corporation, Lateral Load Pile Test, Surry Power Station, July 1968.

21. Stone & Webster Corporation, Rebound and Settlement Analysis, Surry Power Station.

22. R. V. Whitman, Report upon Foundation Dynamics for the Proposed Nuclear Power Plant at Surry, Virginia, Massachusetts Institute of Technology, Cambridge, Mass., July 1967.

23. N. M. Newmark, Effects of Earthquake on Dams and Embankments, Geotechnique, Vol. XV, No. 2, June 1965.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-28 Table 2.4-1 OROGENIC MOVEMENTS IN THE CENTRAL APPALACHIAN REGION Orogenic Episode and Approximate Time Interval Known Area of Influence Maximum Manifestation APPALACHIAN MOVEMENTS Palisadian Late Triassic Belt along central axis of Fault troughs, broad warping, (Carnian-Norian) 190 to 200 already completed mountain basaltic lava, dike swarms million years chain Allegheny Pennsylvania and/or Permian West side of central and Strong folding, also (Westphalian and later) 230 to southern Appalachians, middle-grade metamorphism 260 million years south-east side of northern and granite intrusion at least Appalachians; perhaps also in in southern New England Carolinian Piedmont Acadian Devonian, mainly Middle but Whole of northern Medium-to high-grade Episodic into Mississippian Appalachians, except along metamorphism, granite (Emsian-Givetian 360 to 400 northwest edge; as far intrusion million years) southwest as Pennsylvania Taconic Middle (and late) Ordovician General on northwest side of Strong angular unconformity, (Caradocian, locally probably northern Appalachians, local gravity slides, at least older) 450 to 500 million elsewhere; an early phase in low-grade metamorphism, years Carolinas and Virginia, granodmafic intrusion perhaps general in Piedmont province Avalonian Latest Precambrian 580 to Southeastern Newfoundland, Probably some deformation 600 million years Cape Breton Island, southern uplift of sources of coarse New Brunswick; probably arkosic debris, gravity slides also central and southern Appalachians GREENVILLE (PRE-APPALACHIAN) MOVEMENTS Late Precambrian 800 to 1100 Eastern North America, High-grade metamorphism, million years including western part of granitic and other intrusion Appalachian region

Revision 52Updated Online 09/30/20 Table 2.4-2 DENSITY DATA FOR SAND MEMBERS, FROM ONSITE TESTS IN COFFERDAM Percent Percent Minimum Modified Compaction Maximum Density, Sample Passing Field Density, Proctor, of Modified lb/ft, No. No. 200 Density lb/ft F&R Proctor Dry Vibratory Compaction Relative Density A B Vibration,% Ramming,%

Sand A (Upper Sand)

S1-1 12.3 107.6 NA 108.1 99.5 - - - -

S1-2 10.2 102.9 85.6 108.1 95.2 108.0 - 81 81 S2-1 6.0 101.3 75.9 101.7 99.6 104.0 102.0 92 98 S2-2 12.3 97.3 74.2 107.4 90.6 96.5 94.4 100 76 S2-3 16.8 94.3 66.6 105.3 89.6 92.5 102.1 85 80 S2-4 13.3 96.8 68.5 105.3 91.9 93.6 96.0 100 84 SPS UFSAR S2-5 22.1 105.2 68.8 113.1 93.0 96.0 96.5 100 89 S2-6 4.5 89.7 74.7 100.5 89.3 99.0 97.8 68 65 Sand B (Lower Sand)

S1-3 12.3 94.2 NA 106.9 88.1 S1-4 28.3 105.1 NA 108.9 96.5 S1-5 36.9 110.5 NA 118.8 93.0 S1-6 100.7 124.9 S1-7 103.7 -

2.4-29

Table 2.4-2 (CONTINUED)

Revision 52Updated Online 09/30/20 DENSITY DATA FOR SAND MEMBERS, FROM ONSITE TESTS IN COFFERDAM Percent Percent Minimum Modified Compaction Maximum Density, Sample Passing Field Density, Proctor, of Modified lb/ft, No. No. 200 Density lb/ft F&R Proctor Dry Vibratory Compaction Relative Density A B Vibration,% Ramming,%

Sand B (Lower Sand) (continued)

S1-8 108.1 117.9 S1-9 101.9 -

From Undisturbed Samples from Borings by Dames & Moore Boring Elevation Percent Field Laboratory Date Relative Passing Density Density,%

No. 200 Min Max SPS UFSAR Upper Sand A 46 +1.0 26 103.3 76.8 103.6 98

-4.0 93.0 81.0 99.3 70 49 +2 27 95.0 81.5 103.0 68

-0.5 90.8 79.5 97.6 67 Lower Sand B 46 -30 14 98.3 78.5 101.9 92

-32 6 97.0 75.3 98.5 95 2.4-30

Table 2.4-2 (CONTINUED)

Revision 52Updated Online 09/30/20 DENSITY DATA FOR SAND MEMBERS, FROM ONSITE TESTS IN COFFERDAM Percent Percent Minimum Modified Compaction Maximum Density, Sample Passing Field Density, Proctor, of Modified lb/ft, No. No. 200 Density lb/ft F&R Proctor Dry Vibratory Compaction Relative Density A B Vibration,% Ramming,%

Notes: Minimum Density - Minimum of three trials, tests give excellent reproducibility - ASTM-D20-49-64T.

Vibratory compaction A - Placed oven dry in six layers under surcharge of 1 psi - tapped firmly for 3 minutes after each layer was placed.

B - Same as above except sample saturated with excess water on surface.

Where relative density is computed using vibratory test data, the higher of the two test values was used.

For samples marked NA under Minimum Density, there was significant dry strength, making the test procedure not applicable.

SPS UFSAR 2.4-31

Revision 52Updated Online 09/30/20 Table 2.4-3 GRAIN SIZE ANALYSIS, SAND B, COFFERDAM NO. 1 Percent of Material Passing Sieve Elevation Size -26.6 -27.6 -28.6 -29.6 -30.6 -31.6 -32.1 -32.6 -33.6 -34.6 -35.6 -36.6 1 100 100 3/4 97. 88.4 1/2 85.2 65.8 3/8 100 78.9 54.7 No. 4 100 100 100 97.1 61.9 41.4 100 No. 10 100 99.9 100 93.9 99.4 95.7 100 55.0 31.7 99.6 No. 20 99.9 99.8 99.9 93.5 99.3 100 95.3 99.8 42.8 28.4 99.4 100 No. 40 99.2 99.6 99.8 93.1 99.0 99.8 94.1 99.5 27.3 20.6 98.7 99.9 No. 60 98.1 95.5 98.1 89.4 91.4 96.2 89.7 96.2 17.8 13.5 97.8 99.8 SPS UFSAR No. 140 57.9 26.5 41.0 35.1 15.8 30.0 23.2 43.7 3.5 2.0 58.8 73.6 No. 200 41.2 16.6 28.4 24.2 8.4 16.7 13.9 28.6 2.3 1.4 45.6 52.4 Note: All samples washed through No. 200 mesh screen.

2.4-32

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-33 Table 2.4-4 PENETRATION RESISTANCE FROM BORINGS, SAND A (UPPER SAND)

Adjusted Type Overburden Boring No. Blow Count, N Blow Count, N' Sampler Elevation, ft Effective Stress, psf Group 1 Borings (made from Elevation +26 or higher)

B-8A 25 25 SS -4.2 3210 B-8A 24 24 D&M -9.2 3498 B-9 12 15 D&M -5.0 4160 B-9 53 66 D&M -10.0 4450 B-11 19 24 D&M -3.0 3090 B-11 45 56 D&M -7.5 3350 B-12A 28 28 SS -6.7 3415 B-12A 24 24 SS -13.2 3790 B-13A 65 65 SS -8.2 3440 B-13A 26 26 SS -12.7 3700 B-14A 18 18 SS -12.78 3636 B-14A 26 26 SS -18.78 3980 B-15 48 60 D&M -5.0 3010 B-16 57 71 D&M -11.1 4490 B-17 25 31 D&M +4.0 3680 B-17 38 48 D&M 0.0 3920 B-17 49 61 D&M -5.8 4250 B-18 41 51 D&M -8.8 4030 B-18 36 45 D&M -13.0 4270 B-18 24 30 SS -18.5 4590 B-19A 24 24 SS -3.7 3035 B-19A 14 14 SS -8.7 3350 B-19A 13 13 SS -13.2 3610 B-19A 14 14 SS -18.2 3890 B-19A 15 15 SS -23.2 4190

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-34 Table 2.4-4 (CONTINUED)

PENETRATION RESISTANCE FROM BORINGS, SAND A (UPPER SAND)

Adjusted Type Overburden Boring No. Blow Count, N Blow Count, N' Sampler Elevation, ft Effective Stress, psf Group 1 Borings (made from Elevation +26 or higher)

B-19A 20 20 SS -28.2 4473 B-19A 20 20 D&M -31.6 4670 B-22 24 30 D&M +0.5 3980 B-22 28 35 D&M -4.5 4270 B-23A 29 29 SS +5.0 600 B-23A 11 11 SS 0.0 775 B-24 18 22 D&M -9.0 4570 B-25 50 62 D&M 0.0 3990 B-26 37 46 D&M -4.0 4220 B-26 70 87 D&M -6.3 4350 B-45A 11 14 D&M -3.0 850 B-45A 11 14 D&M -6.3 1040 B-45A 9 11 D&M -9.0 1200 B-45A 10 12 D&M -11.3 1330 B-47 15 19 D&M -4.3 900 B-48 21 21 SS -1.5 680 B-48 15 19 D&M -4.5 850 B-49A 24 30 D&M +4.0 430 B-49A 28 35 D&M +1.2 590 B-49A 33 41 D&M 0.0 660 B-49A 41 51 D&M -2.8 830 B-50A 7 9 D&M -1.0 610 B-50A 41 51 D&M -4.1 790 B-50B 8 8 SS -0.1 584 B-50B 11 11 SS -5.1 874 B-20A 17 17 SS +2.1 540

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-35 Table 2.4-4 (CONTINUED)

PENETRATION RESISTANCE FROM BORINGS, SAND A (UPPER SAND)

Adjusted Type Overburden Boring No. Blow Count, N Blow Count, N' Sampler Elevation, ft Effective Stress, psf Group 1 Borings (made from Elevation +26 or higher)

B-20A 15 15 SS -2.4 800 Notes: D&M - 2.5-inch i.d. sampler driven using 300-lb weight falling 18 inches.

SS - standard penetration test, 1-3/8-inch-i.d. sampler driven by 140-lb weight falling 30 inches.

Plotting of data from samples taken alternatively with both samplers indicates that soil requiring 10 blows per foot. for standard penetration test would require eight blows per foot with the D&M sampler. N' values have been adjusted by this ratio for samples taken with D&M sampler.

Boring designated by suffix A or 8A were made 3 feet south or 3 feet north of original boring.

Where supplementary boring has been made, original boring has been omitted.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-36 Table 2.4-5 PENETRATION RESISTANCE FROM BORINGS, SAND B (LOWER SAND)

Adjusted Type Overburden Boring No. Blow Count, N Blow Count, N' Sampler Elevation, ft Effective Stress, psf Group 1 Borings B-8A 18 18 SS -22.2 4248 B-8A 10 10 SS -27.2 4535 B-8A 18 18 SS -32.2 4825 B-9 25 31 D&M -15.0 4740 B-9 23 29 D&M -17.0 4850 B-11 13 16 D&M -27.0 4490 B-12A 12 12 SS -16.7 3990 B-12A 10 10 SS -22.7 4335 B-12A 10 10 SS -26.7 4567 B-12A 11 11 SS -31.7 4800 B-13A 58 58 SS -18.7 4045 B-13A 18 18 SS -23.7 4333 B-13A 22 22 SS -28.7 4622 B-13A 28 28 SS -33.7 4910 B-14 10 12 D&M -15.8 4760 B-14A 18 18 SS -12.8 3635 B-14A 26 26 SS -17.8 3922 B-14A 30 30 SS -22.8 4210 B-14A 25 25 SS -27.8 4500 B-15 17 21 D&M -24.8 4150 B-15 20 25 D&M -29.5 4430 B-16 12 15 D&M -29.7 5570 B-17 20 25 D&M -35.0 5950 B-18 17 21 D&M -20.5 4710 B-18 15 19 D&M -23.0 4850

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-37 Table 2.4-5 (CONTINUED)

PENETRATION RESISTANCE FROM BORINGS, SAND B (LOWER SAND)

Adjusted Type Overburden Boring No. Blow Count, N Blow Count, N' Sampler Elevation, ft Effective Stress, psf Group 1 Borings (continued)

B-18 13 16 D&M -28.5 5170 B-18 17 21 D&M -32.5 5400 B-19A 15 15 SS -24.2 4242 B-19A 20 20 SS -29.2 4530 B-19A 19 19 SS -34.2 4818 B-23A 14 14 SS -29.0 2683 B-23A 68 68 SS -33.0 2971 B-24 18 22 D&M -23.6 5420 B-24 17 21 D&M -28.5 5700 B-25 62 77 D&M -4.5 4250 Group 2 Borings B-20A 11 11 SS -24.9 2099 B-20A 20 20 SS -29.9 2387 B-20A 20 20 SS -34.9 2675 B-45 9 9 SS -29.3 2380 B-45 19 24 D&M -32.8 2580 B-47 19 19 SS -25.0 2100 B-47 16 20 D&M -28.0 2280 B-47 27 27 SS -31.2 2460 B-47 16 20 D&M -34.0 2620 B-48 27 34 D&M -39.3 2870 B-50 14 14 SS -21.2 1790 B-50A 8 8 SS -21.1 2036 B-50A 13 13 SS -26.6 2352 B-50A 23 23 SS -31.6 2640

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-38 Table 2.4-5 (CONTINUED)

PENETRATION RESISTANCE FROM BORINGS, SAND B (LOWER SAND)

Adjusted Type Overburden Boring No. Blow Count, N Blow Count, N' Sampler Elevation, ft Effective Stress, psf Group 2 Borings (continued)

B-50A 35 35 SS -35.6 2928 Notes: D&M - 2.5-inch i.d. sampler driven using 300-lb weight falling 18 inches.

SS - standard penetration test, 1-3/8 inch-i.d. sampler driven by 140-lb weight falling 30 inch.

Plotting of data from samples taken alternatively with both samplers indicates that soil requiring 10 blows per foot for standard penetration test would require eight blows per foot with the D&M sampler. N' values have been adjusted by this ratio for samples taken with D&M sampler.

Boring designated by suffix A or 8A were made 3 feet south or 3 feet north of original boring.

Where supplementary boring has been made, original boring has been omitted.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-39 Table 2.4-6 DIFFERENTIAL MOVEMENT (FT)

Survey 1 Survey 2 Survey 3 Survey 4 Interfacea 11-10-75 5-20-76 1-10-77 5-26-77 1 .005 .004 .005 .001 2 .006 .001 .004 .003 3 .004 .003 .002 .001 4 .003 .001 .006 .001 5 .005 .002 .010 .001 6 .008 .005 .006 .004 7 .002 .003 .001 .001 8 .002 .009 .013 .005 9 .009 .012 .016 .012 10 .001 .004 .004 .006 11 .001 .001 .001 .001

a. Interface Designations (see Figure 2.4-10)

1. Northwest corner, auxiliary building/southeast side, Unit 1 cable vault.

2. South side, Unit 1 containment/southwest corner, Unit 1 auxiliary feed pump room.

3. Northwest side, Unit 1 containment spray pump room/southwest side, Unit 1 safeguards valve pit.

4. Northeast corner, Unit 1 safeguards valve pit/west side, Unit 1 containment.

5. Northeast side, Unit 1 containment/northwest corner, fuel building.

6. Northeast corner, fuel building/northwest side, Unit 2 containment.

7. Southeast corner, Unit 2 containment/northeast corner, Unit 2 containment spray pump room.

8. Southeast corner, Unit 2 auxiliary feed pump room/southside, Unit 2 containment.

9. North side, service building/south side, Unit 2 containment.

10. Southwest corner, Unit 2 cable vault/northeast corner, auxiliary building.

11. North side, service building/southeast corner, auxiliary building.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-40 Table 2.4-7 PIEZOMETER COMPARISON DATA Piezometric Level Piezometer Tip in Sand 11-2-67 1-26-71 P1A A +1.1 +1.0 P1B A +1.3 +0.7 P1C B +1.9 +1.3 P2A A +3.7 +2.8 P2B B +3.5 +2.3 Table 2.4-8 COMPUTED GROUND MOTION AND INTENSITY, LIQUEFACTION ANALYSIS Ground Motion Intensity, MM Velocity, in./sec Acceleration, g After Neuman Medvedev 6.3 0.07 7.7 8.6 8.3 0.10 8.2 8.9 Table 2.4-9 MODAL DYNAMIC ANALYSIS Shear Stress, lb/ft2 At Elevation -5 At Elevation -30 5 largest peaks 5 largest peaks Velocity at surface, in./sec Max Avg Max Avg 6.1 250 180 380 280 8.3 350 250 540 390

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-41 Table 2.4-10 SHEAR STRESS VALUE FOR YARD AREA, LIQUEFACTION ANALYSIS Shear Stress, lb/ft2 (average of 8 largest peaks)

Ground Acceleration At Elevation -5 At Elevation -30 0.15g (DBE) 390 620 0.25g (hypothetical) 640 1025 Table 2.4-11 ALLOWABLE PILE HOLDINGS I. Vertical Loads Allowable Pile Loading Static load (dead load and fluid and 60 tons each equipment and design live load on floors)

Static and earthquake load 60 tons each, plus 1/3 increase for OBE, or 60 tons each, plus 1/2 increase for DBE II. Lateral Loads OBE 12 kips each DBE 22 kips each Table 2.4-12 FOUNDATION TYPES Structure Type of Foundation Reactor containment 10-ft reinforced-concrete mat on Miocene clay Fuel building 6-ft reinforced-concrete mat into preconsolidated Miocene clays, pile load 60 tons each Auxiliary building 4-ft reinforced-concrete mat on compacted granular fill, replacing Sand A Control house Reinforced-concrete mat on compacted granular fill, replacing Sand A Intake structure 3-ft reinforced-concrete mat on Pleistocene clays

Revision 52Updated Online 09/30/20 Table 2.4-13 DISPLACEMENTS UNDER EARTHQUAKEa Displacement, in.+/-

0.07g Acceleration 0.15g Acceleration Structureb E-W N-S Vertical at External Wall E-W N-S Vertical at External Wall Containment structure At mat (Elevation -40) 0.15 0.15 0.25 0.25 At Elevation +70 0.5 0.5 0.25 0.8 0.8 0.5 At top of dome 0.75 0.75 1.25 1.25 Fuel building Pile movement only 0.12 0.12 0.25 0.25 At foundation mat 0.25 0.35 0.5 0.65 At roof (Elevation +72) 0.4 0.6 0.2 0.7 1.1 0.4 SPS UFSAR Auxiliary building At foundation mat 0.2 0.2 0.4 0.4 At roof (Elevation +66) 0.5 0.5 0.25 0.9 0.9 0.5

a. Basic procedures used to compute values shown in this table, values that essentially represent motions of structures relative to the static position of ground, are given in Section 2.4.8. Soil values and computational procedures used in making these computations are given in Reference 16. The fuel building is supported on fixed end piles, and pile deflections, as indicated, are added to computed soil deflections for this structure in arriving at values shown in this table.

b. Clearance between structures: Fuel building to vapor containment and auxiliary building in. minimum at all levels.

Auxiliary building to vapor containment in. minimum at all levels.

Auxiliary building to control room and battery area in. minimum at all levels.

2.4-42

Table 2.4-13 (CONTINUED)

Revision 52Updated Online 09/30/20 DISPLACEMENTS UNDER EARTHQUAKEa Displacement, in.+/-

0.07g Acceleration 0.15g Acceleration Structureb E-W N-S Vertical at External Wall E-W N-S Vertical at External Wall Control room and battery area At foundation mat - 0.1 0.1 0.15 At Elevation +10 - 0.1 0.3 0.1 0.15 0.6 At Elevation +113 0.2 0.5 0.4 1.2 (roof trusses of turbine building)

Turbine pedestal At mat 0.2 0.25 0.1 0.3 0.4 0.2 At Elevation 58.5 0.3 0.5 0.5 0.8 SPS UFSAR

a. Basic procedures used to compute values shown in this table, values that essentially represent motions of structures relative to the static position of ground, are given in Section 2.4.8. Soil values and computational procedures used in making these computations are given in Reference 16. The fuel building is supported on fixed end piles, and pile deflections, as indicated, are added to computed soil deflections for this structure in arriving at values shown in this table.

b. Clearance between structures: Fuel building to vapor containment and auxiliary building in. minimum at all levels.

Auxiliary building to vapor containment in. minimum at all levels.

Auxiliary building to control room and battery area in. minimum at all levels.

2.4-43

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-44 Table 2.4-14 COMPUTED DEFLECTIONS FOR CONCRETE-FILLED PIPE PILINGS Shear Load at Top, kips Deflection, Free-End Pile, in. Deflection, Fixed-End Pile, in.

12 0.34 0.12 22 0.6 0.23 Note: The two shear loadings quoted correspond to the shear per pile at 0.07g operating-basis earthquake and 0.15g design-basis earthquake ground accelerations, and 0.05 and 0.10 damping, respectively.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-45 Figure 2.4-1 REGIONAL PHYSIOGRAPHY

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-46 Figure 2.4-2 REGIONAL GEOLOGY

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-47 Figure 2.4-3 COLUMNAR GEOLOGIC SECTION

Revision 52Updated Online 09/30/20 Figure 2.4-4 SITE STRATIGRAPHIC COLUMN OF QUATERNARY AND UPPER MIOCENE FORMATIONS SPS UFSAR 2.4-48

Revision 52Updated Online 09/30/20 Figure 2.4-5 PLAN LOCATION OF BORINGS AND PIEZOMETERS SPS UFSAR 2.4-49

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-50 Figure 2.4-6 SUBSURFACE PROFILESSHEET 1

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-51 Figure 2.4-7 SUBSURFACE PROFILESSHEET 2

Revision 52Updated Online 09/30/20 Figure 2.4-8 UNDISTURBED SAMPLE LOCATIONS CONTAINMENT COFFERDAMS SPS UFSAR 2.4-52

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-53 Figure 2.4-9 PENETRATION TEST DATA, SAND A

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-54 Figure 2.4-10 PENETRATION TEST DATA, SAND B

Revision 52Updated Online 09/30/20 Figure 2.4-11 VERTICAL EFFECTIVE STRESS AT SAMPLE LOCATION SPS UFSAR 2.4-55

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-56 Figure 2.4-12 PRECONSOLIDATION LOADS

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-57 Figure 2.4-13 INTERFACE LOCATIONS

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-58 Figure 2.4-14 PIEZOMETRIC READINGS - 1970

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-59 Figure 2.4-15 PIEZOMETRIC READINGS - 1970

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-60 Figure 2.4-16 PIEZOMETRIC READINGS - 1970

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-61 Figure 2.4-17 PIEZOMETRIC READINGS - 1971

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-62 Figure 2.4-18 PIEZOMETRIC READINGS - 1971

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-63 Figure 2.4-19 PIEZOMETRIC READINGS - 1971

Revision 52Updated Online 09/30/20 Figure 2.4-20 PRECIPITATION DATA VICINITY OF SURRY STATION SPS UFSAR 2.4-64

Revision 52Updated Online 09/30/20 SPS UFSAR 2.4-65 Figure 2.4-21 GROUND MOTION DUE TO EARTHQUAKE

Revision 52Updated Online 09/30/20 Figure 2.4-22 NORTH-SOUTH SECTION THROUGH SURRY UNIT 2 SPS UFSAR 2.4-66

Revision 52Updated Online 09/30/20 SPS UFSAR 2.5-1 2.5 SEISMOLOGY 2.5.1 General Site engineering seismology studies were performed to:

1. Evaluate the seismicity of the area.

2. Select the operating-basis earthquake (OBE) and design-basis earthquake (DBE) conditions.

A comprehensive description of the region seismicity (Reference 1) has been prepared, and a brief description of the seismic history of the region is included herein to assist in reviewing the seismicity of the site area.

2.5.2 Tectonics The tectonics of the region are largely dependent on the study of the Appalachian Highlands, especially that of the Blue Ridge and Piedmont provinces. The appearance of the Coastal Plain is a relatively recent event and is related to the late tectonic history of the Piedmont.

Coastal Plain tectonics will be introduced after a basic discussion of the early tectonics of the Appalachian Highlands which form the structural basis for the region. The tectonic features of the region are shown on Figure 2.5-1.

The Appalachian Highlands form a continuous mountain chain extending the length of the eastern North American shoreline from central Alabama to Newfoundland. The tectonic trends (fold axis, faults, foliation, structural pattern, igneous intrusives, etc.) or the Highlands, though locally irregular, generally are remarkably even. They are parallel to one another, and parallel to the general northeast-southwest trend of the mountain chain. Taken broadly, the chain is a series of arcs convex to the northwest. The central arc extends from New York City to southern Virginia (approximately 400 miles), and delineates the region known as the central Appalachians. Most of the site region is within this area. To the south is another arc which extends from southern Virginia to central Alabama (approximately 500 miles), and delineates the region known as southern Appalachians. It includes the most southern parts of the site region.

One of the most prominent structural features of the region is the western edge of the Blue Ridge province, known as the tectonic front (Reference 2). It marks the boundary between the highly deformed and metamorphosed crystalline rocks of the Blue Ridge and Piedmont provinces to the east and unmetamorphosed sedimentary rocks of the Valley and Ridge and Appalachian Plateau provinces to the west. Through most of central and northern Virginia there is no marked evidence of major faulting along the front. South of about latitude 36 degrees North the front is continuously faulted for the entire length of the southern Appalachians, 500 miles. From latitude 36 degrees to the Roanoke area the faulting is high-angle reverse. South of Roanoke it abruptly changes character to systems or low-angle thrust sheets. Some of these thrust faults have throws as great as 10 miles to the northwest. The closest approach of this faulted front to the site is 130 miles to the west.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.5-2 Immediately northwest of the tectonic front is the Valley and Ridge province and the Appalachian Plateau. These are separated by the Allegheny front, which marks the sharp transition between the intensely folded and faulted, rocks of the Valley and Ridge and the gently folded, and only locally-faulted, plateau rocks. The Allegheny front is approximately 200 miles from the site area.

Within the central Appalachian region, the Valley and Ridge province is structurally dominated by large, parallel, northeast-southwest trending fold systems rather than by faults as in the southern Appalachians. The main fold belts are the Massanutten synclinorium, Shenandoah synclinorium, and Nittany anticlinorium, approximately 140, 165 and 180 miles northwest of the site area, respectively. Two major fault zones also traverse the Valley and Ridge province in this area, the Staunton fault and the Little North Mountain fault. The Staunton fault is approximately 145 miles west-northwest of the site area and trends northeast to southwest, parallel with the regional structural fabric. It is a high-angle reverse fault along its 95-mile length through the central Appalachians. Near Roanoke, it joins the Catawba-Pulaski fault system which are low-angle thrust faults. Further northwest, about 150 miles from the site, is the Little North Mountain fault zone. This zone trends parallel to regional structure for a total length of about 190 miles and is a high-angle reverse fault, dipping southeast at its surface exposures.

All of the above mentioned tectonic features of the Valley and Ridge Province, regardless of their tectonic origin, date back to Paleozoic age with the most intense activity during the Allegheny orogeny, 230 to 260 million years ago. No active surface faulting is known in this area.

East of the tectonic front are the Blue Ridge and Piedmont provinces. The Blue Ridge province has been structurally folded and faulted into a complex anticlinorium. Through the area of study it is composed of metamorphosed Precambrian age, 1100 million-year-old gneiss with some small areas of younger Precambrian or Cambrian schists. Small faults are common throughout the anticlinorium. However, as shown on Figure 2.5-1, there is one large fault zone about 55 miles long trending northeast, parallel with the regional structure, just west of Charlottesville, Virginia. The faulting is high-angle reverse. It is about 120 miles northwest of the site. All of the above-mentioned tectonic features of the Blue Ridge are of Paleozoic age, with the most intense activity during the Taconic orogeny, 450 to 500 million years ago. No active surface faulting is known in this area.

Further east is the Piedmont province. It is primarily composed of early-to mid-Paleozoic sedimentary and igneous rocks that have been metamorphosed into schist, gneiss, and granitic gneisses. Within the older crystalline rocks are basins of unmetamorphosed sediments of Triassic age, 180+ million years old.

The boundary between the older Precambrian rocks of the Blue Ridge and the Piedmont does not appear to contain major faulting within the study area. In southern Virginia this transition is marked by a major fold belt known as the James River synclinorium which is faulted along the northwest. The synclinorium is 110 miles west of the site.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.5-3 In Northern Virginia, the eastern Blue Ridge boundary is slowly approached by the western fault system of the Culpeper Triassic Basin until, near the Maryland border, it intersects the Blue Ridge basement rock complex. This Triassic basin border fault, as well as all other known Triassic basin border faults, is a high-angle normal fault.

It is downfaulted on the east side with a vertical displacement of about 10,000 feet, a magnitude common to most large Triassic fault basins. The fault is part of a system that extends a distance of about 125 miles to the northeast and joints the Gettysburg and Newark-Delaware basin system, which are out of the area of study. It is about 110 miles northwest of the site. Other Triassic faults and associated sedimentary basins, which are of common origin and character, located within the study area are:

1. A Triassic basin just south of Charlottesville, Virginia, approximately 110 miles west of the site. It is about 25 miles long and faulted on both the east and west sides.

2. Dan River basin, approximately 120 miles west of the site. It is about 110 miles long and faulted on the west side.

3. Central Triassic faulting, located south of Arvonia syncline approximately 95 miles west of the site. The faulting extends intermittently for 70 miles along a northeast trend. The small basins formed are faulted on the west side.

4. Richmond basin, approximately 55 miles west of the site. It is the closest known faulting to the site area. The basin trends north-northeast and away from the site area. It appears to be about 65 miles long and faulted on both the east and west sides.

5. Deep River-Durham basin approximately 120 miles southwest of the site area. It is faulted primarily on the east side for about 160 miles.

6. Recent aeromagnetic data indicate the possibility of additional Triassic basin faulting east of the Baltimore area as shown on Figure 2.5-1.

Other Piedmont tectonic structures are of Paleozoic age, most of which are contemporaneous with the intense metamorphic and tectonic activity related to the Taconic and Acadian orogenies of 450 and 360 million years ago. The major fold belts include the James River synclinorium, previously mentioned, the Hardware anticline, the Arvonia-Columbia-Quantico syncline trend, the Virginia synclinorium and the Wake-Warren anticlinorium, about 110 miles west, 105 miles northwest, 90 miles northwest, and 80 miles southwest of the site, respectively. Faulting, though common on a localized scale throughout the Piedmont, is not prominent on a regional scale. Aeromagnetic data (Reference 3) indicate a major Paleozoic age lineament through central Virginia. It trends northeast across the State of Virginia and is about 100 miles northwest of the site. The lineament has not been identified by field mapping, but is inferred to be a metamorphosed and recrystallized fault trend (Reference 4).

Additional Paleozoic faulting is associated with the northwest side of the James River synclinorium, about 12 miles west of the site, and two faults associated with the Baltimore,

Revision 52Updated Online 09/30/20 SPS UFSAR 2.5-4 Maryland, area 140 miles north of the site. The James River synclinorium faults are westerly thrust faults, about 50 miles long, trending northeast. The Baltimore area faults trend northeast to north, are normal faults, and extend for a length of about 10 miles.

East of the Piedmont is the Atlantic Coastal Plain. The Coastal Plain is essentially an irregular, thick, dissected, eastward-facing wedge of unconsolidated to semi-consolidated sediments. The basement of this wedge consists of Paleozoic-age Piedmont-type rocks. They are largely igneous and low- to high-grade metamorphic rocks.

The site is located in the Coastal Plain, Physiographic Province. In Virginia, the province is bounded on the east by the Atlantic Ocean and on the west by the Fall Line and the Piedmont Physiographic Province. The crystalline basement rock crops out near the Fall Zone about 50 miles west of the site. From the Fall Zone, the basement surface slopes gently to the southeast, and is overlain by Cretaceous and Tertiary sediments that are about 1300 feet thick at the site.

The Coastal Plain sediments effectively mask the crystalline basement rock so that no faulting can be identified in the area. However, the available regional data and the geologic studies at the site indicate that the overlying Cretaceous and Tertiary sediments are essentially underformed in the site area. The absence of folding and faulting in the exposed sedimentary strata of the Coastal Plain in the vicinity of the site indicates that any displacements along possible unknown faults have been negligible.

2.5.3 Seismicity 2.5.3.1 Earthquake History The site is situated in a region that has experienced only infrequent minor earthquake activity. The closest major earthquakes to the site, the Charleston earthquakes of 1886, had their epicenters about 350 miles southwest of the site. No shock within 50 miles of the site has been large enough to cause structural damage. Since the region has been populated for over 300 years, it is probable that any earthquake of moderate intensity, VI or greater, would have been reported during this period. It is very likely that all earthquakes with intensities of V or greater within the last 200 years have been reported.

The first record of earthquake occurrence in the vicinity of the site was made in the late Eighteenth century. Since then, only about eight earthquakes with epicentral intensities of Modified Mercalli V or greater have been reported within 100 miles of the site. All intensity values in this report refer to the Modified Mercalli Scale as abridged in 1956 by Richter (Table 2.5-1). The intensity scale is a means of indicating the relative size of an earthquake in terms of its perceptible effects. Modified Mercalli intensity, where abbreviated, is designated as MM.

Forty-four earthquakes of intensity V (MM) or greater have been reported within 200 miles of the site from 1774 through September 1995. The largest of these are of epicentral intensity VIII

Revision 52Updated Online 09/30/20 SPS UFSAR 2.5-5 (MM). There has been no resultant structural damage at the site and the associated acceleration is estimated to have been less than 0.05g.

Listed in Table 2.5-2 and shown in Figure 2.5-2 are all known earthquakes from 1774 through September 1995 with epicentral locations within a 50-mile radius of the site and all earthquakes of intensity V (MM) or greater with epicentral locations within 200 miles of the site.

There are no known epicentral locations within a 30-mile radius of the site. The historical earthquakes of the region that are believed to have been felt at the site (Reference 5) are discussed in greater detail in Reference 6.

Most of the nearest recorded earthquakes in the region have occurred in the Piedmont Province, west of the Fall Zone. The closest approach of the Fall Zone to the site is about 50 miles. These shocks are generally related to known faults in the Piedmont rocks. Several shocks have occurred in the Richmond, Virginia, area, which is on the Fall Zone. This activity along the Fall Zone is consistent with similar occurrences both to the north and south of the site area.

2.5.3.2 Correlation of Epicenters with Geologic Structures Relative to the site, the most significant earthquakes and associated seismotectonic zones are believed to be the following:

1. 1897 Giles County, Virginia; intensity VIII (MM) - associated with the Appalachian seismic zone.

2. 1875 Richmond, Virginia; intensity VII (MM) - associated with the central Virginia seismic zone.

3. 1866 Charleston, South Carolina; intensity X (MM) - associated with the Charleston seismic area.

Giles County, Virginia The 1887 earthquake of Giles County, Virginia, of epicentral intensity VIII (MM), is part of what has been described by Bollinger (Reference 7) as the southern Appalachian seismic zone, and its northern extension the northern Virginia-Maryland seismic zone. The zone is characterized by a general northeast-southwest alignment of the epicenters of the larger shocks in the site region. The zone is roughly coincident with tectonic features of the Blue Ridge and the eastern side of the Valley and Ridge provinces. It is indicative of continued deep-seated crustal adjustments along zones of intense ancient tectonic deformations. The latest intense period of major deformation was the Allegheny orogeny, approximately 230 to 260 million years ago.

There is no evidence of active surface faulting along this trend today.

Richmond, Virginia

Revision 52Updated Online 09/30/20 SPS UFSAR 2.5-6 The Richmond area is the eastern-most extension of the central Virginia seismic zone described by Bollinger (References 8 & 9).

The central Virginia seismic zone is a relatively narrow, isolated zone of activity, offset from the Appalachian seismic zone and located in the Piedmont province, oblique to the northeast-southwest structural grain. This zone includes an east-west elongate cluster of low to moderate seismic activity. It extends from Richmond, Virginia, to the edge of the Blue Ridge province. It covers a relatively small area of about 16,500 square miles (Reference 9) and appears to be related to deep seismic activity in the vicinity of Triassic faulting.

The historical record of the region attests to the areal extent of the zone as described above.

The historical record is over 200 years old within a relatively well populated area. Therefore, shocks of intensity V (MM) and greater would have been recorded by the local populace.

Bollinger (Reference 9) has worked out the theoretical earthquake recurrence ratio for different levels of earthquake intensity for the eastern United States. For the large earthquake intensities the recurrence rates are VIII (MM) (51 years), and VII (MM) (13 years) and much less for the lower intensities.

Charleston, South Carolina The seismic history of the southeastern United States is dominated by earthquake activity in the Charleston area. Charleston is about 350 miles south of the site and represents the closest zone of major earthquake activity. Of the 850 earthquakes reported for the southeastern United States in the period of 1754 to 1971, 402 have been in the Charleston area. All of these shocks have been localized to a very limited area around Charleston. Based on the character of the epicentral record and the high frequency of shocks consistently within a small area, the Charleston area is treated as a seismotectonic province by itself. The largest shock that occurred here was the shock of epicentral intensity X (MM) on August 31, 1886. It was felt at the site with an intensity V (MM).

Other Events Another significant series of earthquakes in the Coastal Plain occurred near the northern New Jersey coast about 250 miles northwest of the Surry site, in 1927. The maximum reported epicentral intensity of these earthquakes was VII. Three shocks were felt over an area of about 3000 square miles, from Sandy Hook to Toms River, New Jersey. Highest intensities were felt from Asbury Park to Long Branch, where several chimneys fell, plaster cracked, and articles were thrown from shelves. This shock has not been related to any known geologic feature, although there is some suggestion that it could be related to possible geologic structures associated with the Hudson River Valley to the north.

There have been small shocks in the Coastal Plain closer to the site. Few of these earthquakes caused any structural damage, and they are of interest only in that they indicate the possible presence of unidentified faulting in the basement rock beneath the Coastal Plain.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.5-7 The closest reported earthquakes to the site were two small shocks felt only at Suffolk, Virginia, on April 19, 1918. It is possible that these shocks were not of tectonic origin; however, if they were valid earthquakes, they could indicate the presence of minor faulting in the basement rock close to the site.

2.5.3.3 Identification of Active Faults Based on the studies listed below, there is no known evidence for active faulting in the vicinity of the site (Reference 6).

1. Photo interpretation - Airphotos, topographic maps, and Earth Resources Observing Satellite (EROS) photos of the site area were examined. No evidence of surface rupture, surface warping, or offset of geomorphic features possibly indicative of faulting was found.

2. Aeromagnetic studies - Aeromagnetic mapping of the site and region was examined. There was no aeromagnetic feature indicative of faulting in the vicinity of the site. Some distant, regional features indicative of bedrock faulting were found. They are shown on Figure 2.5-1.

3. No macroseismic activity has been detected in the site area. The closest epicentral location is about 30 miles southeast of the site. It is of intensity III (MM) and not correlative with any known surface feature.

4. Detailed geologic mapping of the site area and vicinity in References 10, 11 and 12 show no evidence of surface or active faulting.

5. Borings drilled at the site indicate continuity of strata and are indicative of no significant (5 feet) fault displacements, dating back at least 2 million years as shown by the top of the erosional Micocene surface.

Regionally, there is no known active surface faulting. Surface expression in the form of active fault scarps have not been observed. Seismic activity within the region is believed to be due to deep-seated crustal adjustments along previous zones of structural deformation and weakness.

2.5.4 Seismic Design 2.5.4.1 Operating-Basis Earthquake (OBE)

The number of cycles of significant motion in a number of earthquake records has been analyzed. Observation indicates maximum acceleration occurs as a single peak (Reference 13)

(never appears more than once). Table 2.5-3 shows the number of cycles of motion in which an acceleration of half the peak is equalled or exceeded in a number of earthquake records. These were taken from accelerograms of the earthquakes listed. A decrease in acceleration to one-half the peak value corresponds approximately to a decrease of one order of intensity on the Modified Mercalli scale and, as a result, conservatively defines the number of cycles of significant motion.

For this site, the operating-basis earthquake is most probably characterized as a sharp, short local earthquake of Intensity VI or less. As indicated on Table 2.5-3, small, sharp earthquakes of

Revision 52Updated Online 09/30/20 SPS UFSAR 2.5-8 this type, such as Golden Gate '57 or Hollister, showed only a few cycles of significant motion.

For the design-basis earthquake, longer duration as well as larger accelerations would be expected. Even for great earthquakes such as El Centro '40 and Taft '52, which were much more intense than anticipated for the design-basis earthquake at Surry, there are only about 10 cycles of significant motion. Use of eight to ten cycles in analyses for the design-basis earthquake is reasonable and conservative.

The number of cycles of significant motion is important in demonstrating that fatigue failure due to stress reversals is not a critical consideration in designing the containment structure.

The number of loading cycles is also considered when evaluating the hazard of liquefaction for the design-basis earthquake.

The maximum estimated earthquake intensity at the Surry site is VI (MM). Based on correlations between intensity and peak acceleration (Reference 14), the peak acceleration values for intensity VI would be 0.0425g vertical and 0.066g horizontal. Also, monitoring sites are differentiated by geological classification (soft, intermediate, and hard). The Surry site most closely resembles the soft site condition (i.e., shallow and deep alluvium) as opposed to intermediate (sedimentary rock) or hard (igneous and metamorphic rock). The interpretation of their graph, of acceleration and intensity (Reference 14) indicates that the mean peak ground acceleration in the maximum direction (horizontal) on a soft site is about 65 cm/sec (Reference 2) or less than 0.07g.

On the basis of the seismic history of the area, it does not appear likely that the site will experience earthquake ground motion of more than a few percent of gravity during the economic life of the facility. However, Class I structures and equipment are designed to withstand a maximum horizontal ground acceleration of 7% of gravity. Vertical acceleration is taken as being two-thirds of horizontal, assumed acting simultaneously and in proper phase to be additive to loads or stresses from horizontal motions. It is believed that this magnitude of ground motion would not be exceeded at the site during an earthquake similar to any previously experienced in the area.

2.5.4.2 Design-Basis Earthquake (DBE)

For the safe and orderly shutdown of the station, all Class I structures and equipment are designed using a seismic factor equal to the ground acceleration at foundation level that might occur due to the maximum credible earthquake. The design-basis earthquake for this site would be a shock similar to one of the following:

1. The eastern Virginia earthquake of 1875 occurred as close to the site as its related geologic structure. It is estimated that the magnitude, m, of this earthquake was about 5 on the Richter Scale. It is probable that this earthquake was related to Piedmont structure, near the Fall Zone. However, it is impossible to locate precisely the epicenter of this shock from the limited data available. Since the earthquake and a subsequent aftershock were felt in Williamsburg, the epicenter of this shock may have been located east of the Fall Zone, in the

Revision 52Updated Online 09/30/20 SPS UFSAR 2.5-9 basement rock of the Coastal Plain. Thus, the conservative assumption is made that an epicentral intensity-VI earthquake could conceivably occur in the basement rock associated with some hypothetical geologic structure. The possibility of such an occurrence is believed to be quite remote.

2. The northern New Jersey earthquake of 1927 occurred close to the site. Since this shock occurred in the Coastal Plain and has not been related to any known geologic structure, the conservative assumption is made that it could be related to a hypothetical geological structure in the basement rock near the site. The magnitude, m, of this epicentral intensity-VII earthquake is estimated to have been about 5. Again, the possibility of such an occurrence is quite remote.

Based on the foregoing evaluation, the design-basis earthquake magnitude is very conservatively assumed to be as large as 5 to 5.5 (epicentral intensity-VII shock), originating in the basement rock close to the site. An occurrence of a shock of the same size as the largest of the 1886 Charleston shocks at a distance of 200 miles or so would result in significantly lower accelerations at the site.

2.5.4.3 Seismicity Measurement A seismic sensing and recording system, incorporating three remote triaxial accelerometers, is installed at the Surry Power Station. The system provides data on the frequency, amplitude, and phase relationship of the seismic response of the Unit 1 reactor containment structure, and provides data on the input vibratory ground motion at the site.

System calibration, testing, recording, and playback are accomplished at the recorder unit located in the control room. Two triaxial accelerometers are installed in the Unit 1 reactor containment structure. One instrument is located on the basement floor (Elevation -27 ft. 7 in.)

and the other instrument is located on the uppermost floor (Elevation 47 ft. 4 in.). The instruments are oriented so that the corresponding axes of each accelerometer are aligned in the same direction, and are located approximately above each other. They are mounted rigidly to the containment structure, so that the accelerometer records can be related to the containment structure movement, as required by Safety Guide 12, dated March 10, 1971.

The third triaxial accelerometer is installed in the free field accelerometer enclosure, located approximately 8 feet west of the security fence and 8 feet south of the sally port. The instrument enclosure is located on a 24-inch concrete foundation, and will record data on the free-field ground motion.

The system is capable of performing its required functions over the appropriate range of environmental conditions. A maintenance program is provided in accordance with the suppliers instruction manual.

The recorder unit will begin recording and initiate an alarm in the control room when actuated by the seismic trigger unit located with the free-field accelerometer. Recording will

Revision 52Updated Online 09/30/20 SPS UFSAR 2.5-10 continue until several seconds after the strong motion ground accelerations have decreased below the trigger setting, and this information will be available to the control room operator.

2.5.5 Estimated Ground Acceleration for Design-Basis Earthquake 2.5.5.1 General It is estimated that the maximum horizontal particle acceleration at planned foundation levels at the site, due to the design-basis earthquake, would be no more than about 15% of gravity.

The vertical motion is taken to be two-thirds of the horizontal motion, acting simultaneously with it.

This estimate has been arrived at by several procedures. One procedure was to compare the physical characteristics of the Surry site with those at sites where strong motion records are available (for example, Taft and El Centro, California). If the propagation of earthquake wave motion through the soil strata at the Surry site is comparable to other locations, and there is no unusual amplification of motion, especially in the frequency regions of significance to structures, then the available strong motion records can be used in estimating maximum ground acceleration at Surry. This comparison of site conditions was based upon the amplification spectrum.

Another procedure was based upon empirical formulas developed from a study of world earthquake occurrence by Japanese seismologists.

2.5.5.2 Amplification Spectrum The amplification spectrum was developed by computing wave motion through a layered model of the earths material, from basement rock up through any desired elevation within the overlying soil. In the model, vertically traveling waves were assumed to propagate through a medium in accordance with wave propagation theory for that medium, assuming any desired degree of damping. Thus, it was possible to model the subsurface conditions on the basis of the following physical properties for each stratum:

1. Thickness.

2. Shear wave velocity.

3. Density.

4. Damping.

A complete description of the procedure is presented in the Duke, Leeds, Matthieson, and Frazer paper (Reference 15).

Amplification spectra for the Surry site and the Taft and El Centro strong motion stations were compared using 10% of critical damping in the overlying soil strata. This damping value is considered conservative under the fairly large earthquake motion assumed for the design-basis earthquake.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.5-11 This comparison indicates that the amplification spectrum at the Surry site is approximately the same as that at the Taft, California, strong motion site, and appears to be lower than that at the El Centro, California, strong motion site.

The maximum expected amplification at the Surry site is about 2, and occurs at longer periods, about 0.75 seconds or more.

Amplification at long periods has been observed in other areas of deep soil strata (Mexico City, San Francisco, etc.). Available records on rocks and earthquake motion indicate that maximum acceleration and dominant frequencies occur at relatively short periods when the amplification ratio for the site is less than 2, and that at periods on the order of 0.75 seconds and longer, accelerations are much smaller. Since the motion at the ground surface is the product of the rock motion times the amplification ratio, it is apparent that, for an amplification spectrum as described here, the maximum acceleration at or near ground surface will be less than twice the maximum accelerations at the rock surface. Orbital particle velocities and displacements at the ground surface would be larger than at the rock surface, since these are larger for the longer periods.

In discussions with consultants of the Atomic Energy Commission, it was agreed that a maximum rock acceleration of 0.07g was appropriate at this site. If it were assumed that the amplification ratio was 2.0 even in the short period portions of the spectrum, a very conservative assumption, the maximum acceleration at the ground surface would be about 0.14g. It is pertinent to compare these theoretical studies with observations. Some recent observations have indicated amplification or soil ground motion over that of bedrock motion on the order of 3 to 4, and increased amplification as the soil thickness increases. These possibilities have been investigated by the use of the amplification spectrum. Figure 2.5-3 presents the results of varying layer thickness. Under small earthquake motions, the soil layers would act essentially as elastic media, and with small amounts of damping, amplification of 3 to 6 would be expected. As the earthquake motion increases in magnitude, damping would increase, thereby reducing the amplification of basement motion for larger earthquakes.

The computed amplification of 3 to 4 is consistent with observed amplification in small earthquakes and moderate soil thickness. Apparently, though, if the properties of the various strata remain essentially similar, the greater the thickness of overburden material, the lower the amplification as a result of damping in the soil.

This fact of decreasing amplification with increasing depth can be more easily visualized for the one-layer system as presented in Reference 16.

Thus these studies indicate:

1. On the basis of computed amplification ratios for the design-basis earthquake, a maximum horizontal ground acceleration of 0.15g is conservative.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.5-12

2. The amplification spectra for the site compare closely with those at other overburden sites for which instrumental records are available. No unusual amplifications would be expected because of the deep overburden. Accordingly, it is possible to evaluate the expected ground motion at Surry by comparison with available instrumental records from other overburden sites.

2.5.5.3 Available Strong Motion Data The magnitude 5 to 5.5 earthquake selected for the design-basis earthquake corresponds to a maximum epicentral intensity of about VII. The maximum intensity reported during any historical earthquake is referenced to the worst conditions at a particular location; i.e., the maximum amplitude of ground motion, adverse subsurface soil conditions, and poor construction.

These conditions may well have existed near the epicenters of the 1875 shock and the 1927 shock, and may have contributed to the maximum intensity reported. It is probable that similar earthquakes near the Surry Power Station site would result in a much lower maximum intensity for structures founded upon the firmer soils of the site. Therefore, the use of an intensity-VII shock as the design-basis earthquake is a conservative assumption. But, given the importance of the proposed facility, it has been assumed that the maximum expected ground motions, based on a historical evaluation of recorded ground motions, will occur at the Surry site.

Since the east coast of the United States has in general been seismically quiet, little data are available for the region around the site. However, a reasonable amount of instrument data is available for California earthquakes in the range of magnitudes from 5 to 5.5 at sites with subsurface conditions similar to the Surry site. Much of these data were originally presented by Gutenberg and Richter (Reference 17), and an attempt was made to develop an empirical relationship between epicentral intensity and maximum ground acceleration. The ground acceleration indicated for a maximum intensity of VII according to the Gutenberg and Richter formula is about 7% of gravity. This work was later continued by Hershberger (Reference 18).

Hershberger used these additional data to refine the Gutenberg and Richter formulas. The ground acceleration indicated for a maximum intensity of VII, according to Hershbergers data, is about 13% of gravity.

Several other investigators have also compiled instrumental data regarding earthquakes in the range of magnitudes being considered in the current study William K. Cloud (Reference 19),

in a paper reporting maximum accelerations during earthquakes, gives instrumental data for several shocks with magnitudes between 5 and 6. All but one of these records correspond to sites on soil. The maximum accelerations recorded during these shocks ranged between 10.2% and 17.3% of gravity, at epicentral distances of less than 13 miles. The average of these accelerations is about 14.5% of gravity.

John H. Wiggins, Jr. (Reference 20), reports maximum ground accelerations at epicentral distances of less than 20 miles for six California earthquakes with magnitudes between 5.2 and

Revision 52Updated Online 09/30/20 SPS UFSAR 2.5-13 5.6. The maximum recorded acceleration for any of these shocks was 15.9% of gravity for a magnitude 5.2 shock at a distance of 12 miles. The epicentral intensity of the shock was VII.

2.5.5.4 Theoretical Studies The possible ground accelerations at the site have also been analyzed on the basis of empirical formulas developed by Dr. Kiyoshi Kanai of Japan.

Using data from Japanese earthquakes, Dr. Kanai (Reference 21) has developed formulas relating earthquake magnitude to maximum particle acceleration in basement rock. According to the Kanai formulas, acceleration in the basement rock at Surry would be about 4 to 7% of gravity, and the maximum ground acceleration at foundation level would be about 10 to 13% of gravity.

2.5.5.5 Summary The preceding studies have evaluated the probable maximum acceleration for the design-basis earthquake at or near the ground surface by three different approaches. All three have indicated that a maximum horizontal ground acceleration of 0.15g at foundation levels is a conservative and reasonable value.

2.5.6 Conclusions It is concluded that the site will not experience any significant earthquake ground motion during the estimated useful life of the nuclear facility. Historically, there is no basis for expecting more than very minor ground motion at the site. However, to provide protection against the remote contingency of an earthquake, the Class I structures and equipment are designed to withstand and remain operating at an earthquake ground motion producing accelerations as high as 7% of gravity. For a safe and orderly shutdown of the station, a maximum horizontal ground acceleration of 15% of gravity is used. This ground acceleration might result from a magnitude 5 to 5.5 earthquake in the basement rock near the site. The seismic history and the known tectonics of the region indicate that the possibility of such an occurrence is quite remote. Vertical accelerations are taken as two-thirds the appropriate maximum ground accelerations acting simultaneously and in phase to produce maximum loads or stresses.

Design is based on the use of response spectra.

Dr. N. M. Newmark has indicated that the primary influence on the response of structures with varying natural frequencies results from:

1. The maximum ground acceleration for structures having a frequency of more than 2 cycles per second.

2. The maximum ground velocity for structures with natural frequencies between 0.3 cycles and 2 cycles per second.

3. The maximum ground displacement for structures with natural frequencies less than about 0.3 cycles per second.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.5-14 As previously indicated, the greatest amplification of the bedrock motion occurs for the longer periods. To allow for this, the spectra have been adjusted in the longer-period portions by normalizing these portions to somewhat higher values than the standard Housner spectra.

For frequencies higher than about 2 cycles per second, the Housner spectra have been followed, normalized to a horizontal ground acceleration of 7% of gravity for the operating-basis earthquake, and 15% of gravity for the design basis earthquake.

In the frequency range between 0.3 cycles per second and 2 cycles per second, Housners average spectra have been normalized to a maximum ground velocity of about 4 in/sec for the operating-basis earthquake, and 9 in/sec for the design-basis earthquake.

For frequencies lower than about 0.3 cycles per second, the spectra were prepared using data suggested by Drs. Newmark and Hall in a recent paper (Reference 22).

Although a relatively high degree of conservatism is introduced into the intermediate frequency range through this approach, the basic principal of average response spectra recorded for sites on deep overburden is adhered to. The resulting spectra used in design are shown on Figures 2.5-5 and 2.5-6 for the operating-basis earthquake and the design-basis earthquake, respectively.

2.5 REFERENCES

1. Weston Geophysical Research, Inc., Seismic Analysis, Surry Nuclear Power Plant Site, Virginia Electric and Power Company, Weston, Massachusetts.

2. G. W. Fischer, F. J. Pettijohn, J. C. Reed, Jr., and N. K. Weaver, Studies of Appalachian Geology Central and Southern, Interscience, New York, 1970.

3. S. K. Neuschel, Correlation of Aeromagnetics and Aeroradio Activity with Lithology in the Spotsylvania Area, Geologic Society of America Bulletin, V. 81, 1970, pp. 3575-3582.

4. M. W. Higgins, Personal Communications, 1973.

5. Weston Geophysical Research Inc., Seismic Analysis, Surry Nuclear Power Plant Site, Virginia Electric Power Company, 1967.

6. Virginia Electric and Power Company, Surry Power Station Independent Spent Fuel Storage Installation, Safety Analysis Report, October 1982.

7. G. A. Bollinger, Historical and Recent Seismic Activity in South Carolina, Bulletin of the Seismological Society of America, Vol. 62, No. 3, 1972.

8. G. A. Bollinger, Virginias Two Largest Earthquakes - December 22, 1875 and May 31, 1897, Bulletin of the Seismological Society of America, Vol. 61, No. 4, pp. 1033-1039, 1971.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.5-15

9. G. A. Bollinger, Seismicity of the Southeastern United States, Bulletin of the Seismological Society of America, Vol. 63, No. 5, pp. 1785-1808, October 1973.

10. G. H. Johnson, Geology of Yorktown, Poquoson West, and Poquoson East Quadrangles, Virginia Division of Mineral Resources, Report of Investigations 30, 1972.

11. K. F. Bick and N. K. Coch, Geology of the Williamsburg, Hog Island, and Bacons Castle Quadrangles, Virginia, Virginia Division of Mineral Resources, Department of Invest, No. 18, 1969.

12. Dames & Moore, Environmental Studies-Proposed Nuclear Power Plant, Surry, Virginia, Virginia Electric and Power Company, December 1, 1966.

13. N. H. Ambrasey and S. K. Sarma, Response of Dams to Strong Earthquakes, Geotechnique, September 1967.

14. Trifunac and Brady, The Correlation of Seismic Intensity Scales with the Peaks of Recorded Strong Ground Motion, Bulletin of the Seismological Society of America, Vol. 65, No. 1, pp. 139-162, February 1975.

15. R. B. Matthieson, C. M. Duke, D. J. Leeds, and J. C. Fraser, Site Characteristics of Southern California, Strong-Motion Earthquake Stations, UCLA Report No. 64-B, February 1964.

16. Surry PSAR, Supplement, pp. S9.13-13 to -18 and Figures S9.13A-l, -2, and -3.

17. B. Gutenberg and C. F. Richter, Earthquake Magnitude, Intensity, Energy and Acceleration, Second Paper, Seismological Society of America Bulletin, Vol. 46, pp.45-145, 1956.

18. J. Hershberger, A Comparison of Earthquake Accelerations with Intensity Ratings, Seismological Society of America Bulletin, Vol. 46, pp. 317-320, 1956.

19. W. K. Cloud, Maximum Accelerations During Earthquakes, unpublished report.

20. J. H. Wiggins, Jr., Construction of Strong Motion Response Spectra from Magnitude and Distance Data, Seismological Society of America Bulletin, Vol. 54, pp. 1257-1269, 1964.

21. K. Kanai, Improved Empirical Formulae for the Characteristics of Strong Earthquake Motions, Proceedings of Japan Earthquake Engineering Symposium, 1966, pp. 1-4.

22. N. M. Newmark and W. J. Hall, Seismic Design Criteria for Nuclear Reactor Facilities, May 25, 1967.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.5-16 Table 2.5-1 MODIFIED MERCALLI INTENSITY (DAMAGE) SCALE OF 1931 (ABRIDGED)

I. Not felt except by a very few under especially favorable circumstances. (I Rossi-Forel Scale).

II. Felt only by a few persons at rest, especially on upper floors of buildings. Delicately suspended objects may swing. (I to II Rossi-Forel Scale.)

III. Felt quite noticeably indoors, especially on upper floors of buildings, but many people do not recognize it as an earthquake. Standing motorcars may rock slightly. Vibration like passing of truck. Duration estimated. (III Rossi-Forel Scale.)

IV. During the day felt indoors by many, outdoors by few. At night some awakened. Dishes, windows, doors disturbed. Walls make creaking sound. Sensation like heavy truck striking building. Standing motorcars rocked noticeably. (IV to V Rossi-Forel Scale.)

V. Felt by nearly everyone, many awakened. Some dishes, windows, ect., broken. A few instances of cracked plaster. Unstable objects overturned. Disturbance of trees, poles, and other tall objects sometimes noticed. Pendulum clocks may stop. (V to VI Rossi-Forel Scale.)

VI. Felt by all. Many frightened and run outdoors. Some heavy furniture moved. A few instances of fallen plaster or damaged chimneys. Damage slight. (VI to VIII Rossi-Forel Scale.)

VII. Everybody runs outdoors. Damage negligible in buildings of good design and construction.

Slight to moderate in well-built ordinary structures. Considerably in poorly-built or badly-designed structures. Some chimneys broken. Noticed by persons driving motorcars.

(VIII Rossi-Forel Scale.)

VIII. Damage slight in specially-designed structures. Considerable in ordinary substantial buildings with partial collapse. Great in poorly-built structures. Panel walls thrown out of frame structures. Fall of chimneys, factory stacks, columns, monuments, walls. Heavy furniture overturned. Sand and mud ejected in small amounts. Changes in well water.

Persons driving motorcars disturbed. (VIII+ to IX Rossi-Forel Scale.)

IX. Damage considerable in specially-designed structures. Well-designed frame structures thrown out of plumb. Great in substantial buildings, with partial collapse. Buildings shifted off foundations. Ground cracked conspicuously. Underground pipes broken. (IX+

Rossi-Forel Scale.)

X. Some well-built wooden structures destroyed. Most masonry and frame structures destroyed with foundations. Ground badly cracked. Rails bent. Landslides considerable from river banks and steep slopes. Shifted sand and mud. Water splashed (slopped) over banks. (X Rossi-Forel Scale.)

XI. Few, if any, (masonry) structures remain standing. Bridges destroyed. Broad fissures in ground. Underground pipelines completely out of service. Earth slumps and land slips in soft ground. Rails bent greatly.

XII. Damage total. Waves seen on ground surface. Lines of sight and level distorted. Objects thrown into the air.

Revision 52Updated Online 09/30/20 Table 2.5-2 SIGNIFICANT EARTHQUAKES OF ALL EARTHQUAKES WITHIN 50 MILES OF SITE AND ALL EARTHQUAKES OF INTENSITY V OR GREATER WITHIN 200 MILES OF SITEb Epicentral N W Perceptible Distance Year Date Time Approximate Location Intensity Lat Long Area (Sq Mi) from Site 1774 Feb. 21 14: VI Va. 37.3 77.4 58,000 43.5 1774 Feb. 22 05: V-VI Va. 37.5 77.5 - 50.8 1802 Aug. 23 05: V Richmond, Va. 37.6 77.4 - 49.3 1807 Apr. 30 04:00 V Richmond-Fredricksburg Area - - - -

1811a Dec. 16 02:00 XII New Madrid, Mo. 36.6 89.6 2,000,000 705 1812a Jan. 23 - XII New Madrid, Mo. 36.6 89.6 - 705 1812a Feb. 7 - XII New Madrid, Mo. 36.6 89.6 - 705 1812 Apr. 22 04:00 IV Richmond, Va. 37.6 77.4 - -

1816 Dec. 31 13:00 III Norfolk, Va. 36.8 76.3 - 33.5 SPS UFSAR 1824 July 15 11:20 V W. Va.-Ohio - - 63,000 -

1826 Aug. 9 21:00 I-III Richmond, Va. 37.6 77.4 - -

1826 Aug. 10 12:00 II-III Richmond, Va. 37.6 77.4 - 49.3 1828 Mar. 9 22:00 V W.-Central Va. - - 218,000 49.3 1833 Aug. 27 06:00 V Charlottesville-Richmond, Va. 37.75 78. 61,000 84.3 1852

a. Beyond 200-mile distance but significant to study.

b. 1774 through 1995.

2.5-17

Table 2.5-2 (CONTINUED)

Revision 52Updated Online 09/30/20 SIGNIFICANT EARTHQUAKES OF ALL EARTHQUAKES WITHIN 50 MILES OF SITE AND ALL EARTHQUAKES OF INTENSITY V OR GREATER WITHIN 200 MILES OF SITEb Epicentral N W Perceptible Distance Year Date Time Approximate Location Intensity Lat Long Area (Sq Mi) from Site 1852a Apr. 29 13:00 VI Va.-N.C.-Tenn. (Mt. Rogers in 36.6 81.6 187,000 270 Va.)

1852 Nov. 2 18:35 VI Eastern Va. 37.75 78. 32,000 84.3 1853 May 2 09:20 V-VI Va.-W Va.-Ohio 38.5 79.5 72,000 179 1861 Aug. 31 05:22 VI SW Va.-W N.C. - - 300,000 -

1870a Oct. 20 11:25 IX Canada (Baie St. Paul) 47.4 70.5 1,000,000 780 1871 Oct. 9 - VII Wilmington, Del. 39.75 75.5 - 195 1872 June 4 22:00 III Chesterfield 37.60 77.4 9000 46.4 1875 Dec. 22 - VI Arvonia, Va. 37.5 77.5 50,000 50.8 SPS UFSAR 1883 Mar. 11 18:57 IV-V Harford County, Md. 39.5 76.5 - 164.5 1883 Mar. 12 00: V Harford County, Md. 39.5 76.4 - 163.7 1885 Jan. 2 21:16 V Loudon Co. Va Md.-Va. Border 39.2 77.5 9000 149.5 1885 Aug. 9 23:35 V Va. 37.7 78.8 29,000 121.5 1886a Aug. 31 21:51 X Charleston, S.C. 32.9 80.0 2,000,000 352 1889 Mar. 8 18:40 VI SE Pa. 40.0 76.75 4000 197 1897a May 3 12:18 VI Pulaski, Va. 37.1 80.7 150,000 222.5

a. Beyond 200-mile distance but significant to study.

2.5-18

b. 1774 through 1995.

Table 2.5-2 (CONTINUED)

Revision 52Updated Online 09/30/20 SIGNIFICANT EARTHQUAKES OF ALL EARTHQUAKES WITHIN 50 MILES OF SITE AND ALL EARTHQUAKES OF INTENSITY V OR GREATER WITHIN 200 MILES OF SITEb Epicentral N W Perceptible Distance Year Date Time Approximate Location Intensity Lat Long Area (Sq Mi) from Site 1897a May 31 13:58 VIII Giles County, Va. 37.3 80.7 280,000 222 1897 June 28 - V Roanoke, Va. 37.3 79.9 9500 176.5 1897 Dec. 18 18:45 V Ashland, Va. 37.7 77.5 10,000 57.2 1906 May 8 12:41 V Del. 38.7 75.7 400 118.2 1907 Feb. 11 08:22 VI Arvonia, Va. 37.7 78.3 2000 94.6 1908 Aug. 23 04:30 V Powhatan, Va. 37.5 77.9 450 71.0 1909 Apr. 2 02:25 V-VI W. Va.-Md.-Pa. 39.4 78.0 2500 174.5 1910 May 8 16:10 V Arvonia, Va. 37.7 78.4 350 99.5 1918 Apr. 9 21:09 V-VI Luray, Va. 38.7 78.4 100,00 139.0 SPS UFSAR 1918 Apr. 19 11:55 III Norfolk, Va. 36.9 76.3 - 33.2 1919 Sept. 5 21:46 VI Front Royal, Va. 38.8 78.2 - 141.0 1921 Aug. 7 01:30 VI New Canton, Va. 37.8 78.4 2800 100.5 1923 Dec. 31 - V Clarke County, Va. Boyse 39.2 78. - 156.5 Section 1924 Jan. 1 - IV-V Clarke County, Va. 39.2 78. - 156.5 1924 Dec. 25 - V Roanoke, Va. 37.3 75.9 - 177.0

a. Beyond 200-mile distance but significant to study.

2.5-19

b. 1774 through 1995.

Table 2.5-2 (CONTINUED)

Revision 52Updated Online 09/30/20 SIGNIFICANT EARTHQUAKES OF ALL EARTHQUAKES WITHIN 50 MILES OF SITE AND ALL EARTHQUAKES OF INTENSITY V OR GREATER WITHIN 200 MILES OF SITEb Epicentral N W Perceptible Distance Year Date Time Approximate Location Intensity Lat Long Area (Sq Mi) from Site 1925 July 14 16:20 IV Richmond, Va. 37.6 77.4 - 49.3 1927 June 10 02:16 V Augusta County, Va. 38. 79. 2500 140.0 1928 Oct. 30 06:45 IV Richmond, Va. 37.5 77.5 3100 50.8 1929 Dec. 25 21:56 VI Albemarle County, Va. 38.1 78.5 1000 120.0 1932 Jan. 4 23:05 V Buckingham County, Va. 37.6 78.6 800 110.3 1935a Nov. 1 03:30 V Elkins, W.Va. 38.9 75.9 - 212.0 1939 Nov. 14 21:54 V Salem County, N.J. 39.6 75.2 6000 187.2 1940 Mar. 25 - V Shenandoah Valley, Va. 38.9 78.6 400 157.5 1948 Jan. 4 - VI Buckingham, Va. 37.5 78.5 1700 108.3 SPS UFSAR 1949 May 8 06:01 IV-V Powhatan-Richmond, Va. 37.6 77.9 2700 72.5 1950 Nov. 26 02:45 V Buckingham County, Va. 37.7 78.4 900 99.5 1951 Mar. 9 02:00 - Richmond, Va. 37.6 77.4 - 49.3 1959a Apr. 23 20:58:41 VI Giles County, Va. 37.5 80.5 3000 210.0 Beyond 200-mile distance but significant to study.

1966 May 31 06:14:02 V Powhatan, Va. 37.6 78.0 28,000 78.8

a. Beyond 200-mile distance but significant to study.

b. 1774 through 1995.

2.5-20

Table 2.5-2 (CONTINUED)

Revision 52Updated Online 09/30/20 SIGNIFICANT EARTHQUAKES OF ALL EARTHQUAKES WITHIN 50 MILES OF SITE AND ALL EARTHQUAKES OF INTENSITY V OR GREATER WITHIN 200 MILES OF SITEb Epicentral N W Perceptible Distance Year Date Time Approximate Location Intensity Lat Long Area (Sq Mi) from Site 1968a Dec. 10 04:12 V SE N. J. 39.7 74.6 - 208.0 1969 Dec. 11 18:44 V Richmond, Va. 37.8 77.4 6500 61.0 1969 Dec. 11 23:44 V Richmond, Va. 37.8 77.4 3500 61.0 1973 Mar. 1 03:30 V-VI Delaware County, Pa. 39.8 75.3 - 200 1974 Mar. 23 09:49 - Shenandoah Valley, Va. 38.92 77.78 - 135.06 1974 Apr. 28 09:19 IV Wilmington, Del. 39.75 75.5 - 195.0 1974 Nov. 7 16:31 IV Charlottesville, Va. 37.75 78.20 - 92.45 1977 Feb. 10 19:14 V (VI) Wilmington, Del. 39.75 75.5 - 195.0 1977 Feb. 27 20:05 V Charlottesville, Va. 37.90 78.63 - 118.11 SPS UFSAR 1977 Sept. 30 20:53 - Louisburg, N.C. 36.05 78.35 - 120.46 1978 Feb. 25 03:53 IV Reidsville, N.C. 36.19 79.30 - 159.98 1978 Apr. 26 19:30 - Martinsburg, W. Va. 39.63 78.20 - 189.00 1978 Jul. 16 06:40 V Lancaster, Pa. 39.93 76.34 - 191.85 1978 Oct. 6 19:25 V York, Pa. 39.97 76.51 - 193.93 1978 Oct. 29 12:22 - Louisa County, Va. 38.03 78.10 - 97.86

a. Beyond 200-mile distance but significant to study.

b. 1774 through 1995.

2.5-21

Table 2.5-2 (CONTINUED)

Revision 52Updated Online 09/30/20 SIGNIFICANT EARTHQUAKES OF ALL EARTHQUAKES WITHIN 50 MILES OF SITE AND ALL EARTHQUAKES OF INTENSITY V OR GREATER WITHIN 200 MILES OF SITEb Epicentral N W Perceptible Distance Year Date Time Approximate Location Intensity Lat Long Area (Sq Mi) from Site 1978 Nov. 15 08:33 - Richmond, Va. 37.65 77.55 - 58.13 1979 Nov. 6 04:05 - Cumberland County, Va. 37.44 78.26 - 88.72 1979 Nov. 11 07:22 - Richmond, Va. 37.72 77.47 - 43.48 1980 Apr. 26 03:60 - Hanover County, Va. 37.77 77.58 - 64.47 1980 May 18 03:31 - Powhatan County, Va. 37.58 77.94 - 74.70 1980 May 18 22:34 - Louisa County, Va. 37.97 78.07 - 94.08 1980 Aug. 4 10:13 - Louisa County, Va. 38.07 77.76 - 85.85 1980 Sept. 21 10:03 - Marlinton, W. Va. 38.18 80.07 - 198.04 1980 Sept. 26 01:32 - Louisa County, Va. 38.07 77.76 - 86.22 SPS UFSAR 1980 Sept. 26 05:04 - Warrenton, Va. 38.78 77.72 - 124.97 1980 Oct. 11 22:40 - Louisa County, Va. 38.12 77.81 - 90.22 1980 Oct. 14 01:20 - Floyd County, Va. 37.08 80.23 - 195.53 1980 Nov. 5 21:48 Felt Marlinton, W. Va. 38.18 79.90 - 189.37 1980 Nov. 25 07:44 - Marlinton, W. Va. 38.10 80.12 - 198.83 1981 Jan. 19 21:54 - Buckingham County, Va. 37.73 78.44 - 103.95

a. Beyond 200-mile distance but significant to study.

b. 1774 through 1995.

2.5-22

Table 2.5-2 (CONTINUED)

Revision 52Updated Online 09/30/20 SIGNIFICANT EARTHQUAKES OF ALL EARTHQUAKES WITHIN 50 MILES OF SITE AND ALL EARTHQUAKES OF INTENSITY V OR GREATER WITHIN 200 MILES OF SITEb Epicentral N W Perceptible Distance Year Date Time Approximate Location Intensity Lat Long Area (Sq Mi) from Site 1981 Jan. 21 16:30 - Buckingham County, Va. 37.77 78.42 - 103.99 1981 Feb. 11 13:44 IV Buckingham County, Va. 37.72 78.44 - 103.70 1981 Feb. 11 13:51 III Buckingham County, Va. 37.75 78.41 - 102.95 1981 Feb. 11 13:52 Felt Buckingham County, Va. 37.72 78.45 - 104.21 1981 Mar. 20 04:02 - Richmond, Va. 37.52 77.68 - 59.96 1981 Apr. 9 07:13 - Powhatan County, Va. 37.48 77.82 - 66.12 1981 Apr. 9 07:35 - Powhatan County, Va. 37.47 77.87 - 68.51 1981 Apr. 16 13:49 - Cumberland County, Va. 37.61 78.22 - 89.78 1981 June 6 08:06 - Bath County, Va. 38.21 79.51 - 170.57 SPS UFSAR 1981 July 30 12:00 - Louisa County, Va. 38.19 78.09 - 104.50 1981 Oct. 3 09:56 - Burlington, N.C. 36.01 79.35 - 168.20 1981 Nov. 23 13:15 - Augusta County, Va. 38.24 79.05 - 149.15 1984 Apr. 23 01:36 - Lancaster County, Pa. 39.95 76.32 - 192.5 1984 Aug. 17 18:05 - Fluvanna County, Va. 37.87 78.32 - 101.3 1986 Feb. 2 21:50 - Hanover County, Va. 37.60 77.39 - 48.2

a. Beyond 200-mile distance but significant to study.

b. 1774 through 1995.

2.5-23

Table 2.5-2 (CONTINUED)

Revision 52Updated Online 09/30/20 SIGNIFICANT EARTHQUAKES OF ALL EARTHQUAKES WITHIN 50 MILES OF SITE AND ALL EARTHQUAKES OF INTENSITY V OR GREATER WITHIN 200 MILES OF SITEb Epicentral N W Perceptible Distance Year Date Time Approximate Location Intensity Lat Long Area (Sq Mi) from Site 1986 Dec. 10 11:30 - Richmond, Va. 37.59 77.47 - 51.0 1990 Jan. 13 20:47 - Baltimore County, Md. 39.37 76.85 - 151.7 1991 Mar. 15 06:54 - Goochland County, Va. 37.75 77.91 - 77.4 1993 Mar. 15 04:29 - Howard County, Md. 39.20 76.87 - 140.1 1994 Aug. 6 19:54 - Pamlico County, N.C. 35.10 76.79 - 142.7 1995 Aug. 3 13:07 - James City County, Va. 37.40 76.69 - 15.9

a. Beyond 200-mile distance but significant to study.

b. 1774 through 1995.

SPS UFSAR 2.5-24

Revision 52Updated Online 09/30/20 SPS UFSAR 2.5-25 Table 2.5-3 EARTHQUAKE CYCLES OF SIGNIFICANT MOTION Number of Cycles Earthquake Record of Significant Motiona Taft 1952 S69E 9 Taft 1952 N21E 9 El Centro 1940 NS 10 El Centro 1940 NS 2 Golden Gate 1957 NE 3 Golden Gate 1957 S80E 5 Olympia 1949 S86W 7 Helena 1935 NS 5 Helena 1935 EW 5 Eureka N79 E 4 Eureka N11W 7 Parkfield Site 2 2 Parkfield Site 5 N5W 1 Parkfield Site 5 N85E 1 Hollister 3

a. Number of cycles in which acceleration equals or exceeds one-half the peak acceleration for direction recorded.

Revision 52Updated Online 09/30/20 SPS UFSAR 2.5-26 Figure 2.5-1 REGIONAL TECTONICS

Revision 52Updated Online 09/30/20 SPS UFSAR 2.5-27 Figure 2.5-2 REGIONAL EPICENTER MAP

Revision 52Updated Online 09/30/20 Figure 2.5-3 AMPLIFICATION SPECTRA FOR THREE TYPICAL EARTHQUAKES 10% DAMPING SPS UFSAR 2.5-28

Revision 52Updated Online 09/30/20 Figure 2.5-4 AMPLIFICATION SPECTRA FOR FOUR OVERBURDEN DEPTHS 10% DAMPING SPS UFSAR 2.5-29

Revision 52Updated Online 09/30/20 Figure 2.5-5 RESPONSE SPECTRA OPERATIONAL-BASIS EARTHQUAKE SPS UFSAR 2.5-30

Revision 52Updated Online 09/30/20 Figure 2.5-6 RESPONSE SPECTRA DESIGN-BASIS EARTHQUAKE SPS UFSAR 2.5-31

Revision 52Updated Online 09/30/20 SPS UFSAR 2.5-32 Intentionally Blank

v t e Letter Sequence Other
EPID:L-2020-LRO-0076, (Open)
Initiation Acceptance... Administration Questions Answers Results Approval... Other: ML21208A367, ML21208A409, ML21208A418, ML21208A424, ML21208A429, ML21210A125, ML21210A126, ML21210A127, ML21210A128, ML21210A129, ML21210A133, ML21210A134, ML21210A135, ML21210A136, ML21210A137, ML21210A138, ML21210A139, ML21210A140, ML21231A013
MONTHYEAR2020-09-30 [Table View]

ML21208A418

Text

2.1 REFERENCES

2.2 REFERENCES

SUMMARY

2.3 REFERENCES

2.4 REFERENCES

Subject:

2.5 REFERENCES

Navigation menu

Search