Vogtle AP1000 Seismic AssessmentStatus

March 1, 2007Don Moore, Consulting Engineer

Southern Nuclear Operating Company

Proposed Layout

Unit 3Unit 4

~800 feet ~1400 feet

ExistingUnits 1 & 2

North

Vogtle ESP & COL Schedule

FirstConcrete

FuelLoad 11/14

Site Work

2005 2010 20152006 2007 2008 2009 2011 2012 2013 2014

COL

ESP filed 8/06

File COLACOL

Approval

ESPApprovalESP

CommercialOperationUnit 3 - 5/15Unit 4 - 5/16

Cross Section Normal to PBF

Development of VogtleSite-Specific SSE

Updated EPRI PSHA• Update of Charleston Seismic Source• New Ground Motion Models (EPRI-04)• Did not use revision to sigma nor CAV filter

Site amplification per Approach 2ADefine SSE @ ground surface at hypothetical outcrop of highest competent in-situ material• Top of Blue Bluff marl (~86’depth)

Vertical SSE = V/H x Horiz. SSE

SSE at 86-foot Depth Control Point

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Horizontal SSE

Vertical SSE

Vogtle ESP SSE at Top of Blue Bluff Marl (86-foot Depth) [GMRS]

Vogtle Site-Specific AP1000 Nuclear Island 3D SASSI Analysis

Required for site compatibility due to site SSE & soil profile

Input motionSoil profile propertiesDevelop in-column time historiesUpdate Westinghouse 3D SASSI model of AP1000 NI

Analysis is in progress

Vogtle Site-Specific 3D SASSI/AP1000 NI

Input motion at outcrop at Elevation of AP1000 NI foundation (40’depth)

• Development of Horiz. SSE Spectrum at hypothetical outcrop at 40’ depth is consistent w/ PSHA/site amplification approach used for Vogtle ESP Horiz. SSE (86’depth)

• Used Vogtle Units 1&2 Engineered Backfill properties for fill above the top of Blue Bluff Marl (86’depth) [Expect similar values for Units 3&4]

• Used the same V/H ratio function @ 86’ depth to define vertical SSE at 40’ depth

Vogtle Horizontal SSE, Outcrop 40' Depth

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AP1000 HorizontalSSEHorizontal SSE @40' Depth Outcrop

(Input for Site-specific SSI analysis of AP1000 NI) [FIRS]

Elevation 220

Vogtle input motion SSE at hypothetical outcrop at 40’ depth for control point seismic input for site-specific SSI analysis of AP1000 nuclear island. These are Foundation Input Response Spectra (FIRS)

~900’ Coastal Plain

Sediments

76’ BlueBluff Marl

Vogtle ESP SSE defined at the free ground surface of a hypothetical outcrop of the highest competent in-situ layer (top of Blue Bluff Marl at depth of 86’). These are theSite-Specific Ground Motion Response Spectra (GMRS)

~86’Engineered

Backfill

Vogtle Site-Specific 3D SASSI/AP1000

Nuclear Island

Not to scale

Vogtle Site Specific 3D SASSI/AP1000 NI

Soil Profile Properties (Lower Bound, Best Estimate & Upper Bound)

• Mean soil profile properties base on site profile randomization to obtain site amplification factors

• Best Estimate=mean soil profile properties

• Used either + and – one sigma of Vs or 1/1.5 and 1.5 mean Gs whichever produced the largest spread

Vogtle Site Specific 3D SASSIAP1000 Nuclear Island

Calculate in-column time historiesat foundation horizon (40’depth)• N-S, E-W, and vertical TH for each of the 3 soil profiles

• Total 9 Time Histories (3 orthogonalcomponent TH x 3 soil profiles = 9 TH)

• Calculate Fourier amplitude spectra to determine highest frequency of interest (Freq. where Fourier amplitude falls

below 10% of max. Fourier amplitude)

Vogtle Site Specific 3D SASSIAP1000 Nuclear Island

Updating Westinghouse 3D SASSIModel of AP1000 NI

• Finite element mesh size adjustment to capture highest frequency of interest

• Vogtle 3 soil profiles (LB, BE, UB)

• Vogtle in-column time histories associated with each of the 3 soil profiles

• Initial runs using coherent motion (no coherency functions used)

Assessment of Vogtle AP1000 NIISRS to AP1000 NI DCD ISRS

Six key locations specified in the DCD

Three Vogtle ISRS (LB,BE,UB) < Certified Design ISRS @ each location ?

Identify any ISRS exceedances & their significance

Determine the need to use approved coherency functions

Assessment of Vogtle AP1000 NI ISRS to AP1000 NI DCD ISRS

Preliminary Results:

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ni20 Model - El. 265'

NOV 20 200519:25:57

ELEMENTS

REAL NUM29702734

ASB at Elevation 333.12’

ASB at Elevation 333.12’FRS Comparison X Direction

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ASB at Elevation 333.12’

FRS Comparison Y Direction

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ASB at Elevation 333.12’

FRS Comparison Z Direction

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