ML061920330
| ML061920330 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 04/14/2006 |
| From: | Southern Nuclear Operating Co |
| To: | Office of Nuclear Reactor Regulation |
| araguas C, NRR/DNRL/NAPB,415-3637 | |
| References | |
| Download: ML061920330 (57) | |
Text
Vogtle Early Site Permit Seismic Activities NRC Public Meeting April 14, 2006 1
Meeting Objectives
- Inform the NRC
- Obtain NRC feedback 2
Agenda 9:00 Introductions and Opening Remarks NRC/SNC 9:10 ESP Site Location and Description Tom McCallum SNC ESP Technical PM 9:20 Ground Motion Program Overview Don Moore SNC Consulting Engineer 9:40 Geological and Seismological Scott Lindvall Investigations William Lettis & Associates 10:00 Geophysical and Geotechnical Jose Clemente Investigations Bechtel Corporation
Agenda (continued) 10:20 Summary of Seismic Hazard for Robin McGuire Vogtle Site Risk Engineering, Inc 10:40 Determination of SSE Ground Robin McGuire Motion Risk Engineering, Inc 11:10 Plans for AP1000 and Vogtle Site Don Moore Assessment SNC Consulting Engineer 11:30 Discussion NRC and SNC 11:50 Opportunity for Public Comment 12:00 Adjourn
ESP Site Location and Description Tom McCallum ESP Technical Project Manager Southern Nuclear Operating Company
Southern Company Plan
- Two Units at VEGP Site
- Westinghouse AP-1000 Technology
- Decision to construct pending 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 ESP Prep File ESP ESP Begins 8/06 Approval ESP COL Prep COL Begins File COLA Approval Commercial COL Operation Unit 3 - 5/15 Unit 4 - 5/16 Procurement (Long Lead Items) Fuel Site First Load Prep Concrete 11/14 Site Work 6
Plant Vogtle 7
Unit 3 Containment North 8
8
Savannah River Existing VEGP Site Intake Structure Switchyard Power Block Cooling Towers 9
Intake Access Road and Structure Intake Line Expanded Barge Slip Batch Plant Discharge Line Haul Route Switchyard Expanded PA Construction Unit 4 Unit 3 ISFSI Entrance (shared)
Construction Laydown Area Cooling Towers 10
Ground Motion Program Overview Don Moore Consulting Engineer Southern Nuclear Operating Company
Seismic Program Overview Seismic Program Organization Southern Nuclear Ground Motion Overall Review and Advisory Project Management Panel Bechtel Project Mgt and Geotechnical Tasks William Lettis Risk Engineering Bechtel San Francisco
& Associates PSHA & Site Transfer Geological and Development of SSE Functions Seismological Tasks 12
Seismic Program Overview Ground Motion Review and Advisory Panel Reasons for Formation:
- Seismic hazard considerations are significant
- Approach to developing SSE is being updated
- Seismic ground motion issues are complex and require multi-disciplined effort
- Review by outside experts to ensure defensible approach 13
Seismic Program Overview Ground Motion Review and Advisory Panel Panel Members Member Area of Expertise Dr. Martin Chapman Southeastern US seismicity Dr. Robert P. Kennedy Seismic ground motion for design Dr. Carl Stepp Probabilistic Seismic Hazard Analysis (PSHA)
Dr. Robert Youngs Site response to seismic input at rock 14
Seismic Program Overview Ground Motion Review and Advisory Panel Activities
- Two panel meetings have been held to review tasks and comment
- Provided ongoing review and comment on specific tasks, e.g., Charleston Update 15
Seismic Program Overview Other Outside Assistance Savannah River Site
- Provided technical staff support for seismic survey and other tasks
- Provided significant amount of data from SRS geotechnical investigations 16
Seismic Program Status Activity Schedule Geological, seismological, and geotechnical Complete investigations for ESP Update of EPRI-SOG per RG 1.165 including Complete update of Charleston Source Rock hazard characterization April 2006 Soil/rock profile development and site transfer May 2006 function development Site-specific SSE June 2006 Submit ESP application August 2006 Interactions with Westinghouse on AP1000 COLA 17
Geological and Seismological Investigations Scott Lindvall William Lettis & Associates, Inc.
William Lettis & Associates, Inc
Evaluation of Tectonic Features within 25 miles
- Literature review
- Contact local researchers
- Air photo interpretation
- Aerial reconnaissance
- Field reconnaissance
- Review of seismicity
- Seismic reflection profiles at Vogtle 19
Site Vicinity Tectonic Features and Seismicity (25-mile radius) 20
Summary of Geological and Seismological Investigations
- None of the Site Vicinity (25 miles) or Site Area (5 miles) Tectonic Features are Capable Tectonic Sources
- Non-tectonic deformation and related features mitigated by removal of strata overlying Blue Bluff marl 21
Pen Branch Fault
- Triassic Basin normal fault that separates Paleozoic crystalline basement from Triassic basin sediments
- Reactivated as a SE-side-up reverse fault in Cenozoic
- Youngest deformed unit is late Eocene
- Non-capable PBF associated with similar, non-capable faults of the Atlantic Coastal Plain that exhibit a lack of post-Miocene activity
- No geomorphic expression in Pleistocene Savannah River terraces or older landscape 22
Reasons for Seismic Reflection Survey
- Vogtle ESP geologic investigation indicated the location of the Pen Branch fault and basin boundary could be close to the ESP site
- The PBF is non-capable, but separates rocks of different velocities
- Seismic survey was performed to determine:
- 1. If PBF is close to the site, and
- 2. The geometry of the Dunbarton Basin boundary to help constrain velocity profile 23
Seismic Reflection Profiles 24
Location of Pen Branch fault at top of basement in seismic profile Crystalline Structure Contours of top of Blue Bluff Marl Basement from Drawing AX6DD377 Rock 45 Pen Branch Fault Triassic Basin Rock Vertical Projection from Top of Basement 25
NW Section through Site B-1003 Coastal Plain Sediments Fault Tip Crystalline Basement Triassic Basin Rock Rock 26
Results of Reflection Survey
- Non-Capable Pen Branch fault imaged
- Strikes N34E to N45E and dips 45SE
- Juxtaposes Triassic basin rocks against higher velocity Paleozoic crystalline rocks to NW
- Basement rocks vertically separated across fault (SE-side-up) and consistent with separations and sense of slip observed at SRS
- Triassic basin rock underlies two proposed units 27
Geophysical and Geotechnical Investigations Jose Clemente Principal Geotechnical Engineer Bechtel Corporation
ESP Subsurface Investigation 12 borings, including 1 to a depth of 1,338 ft (290 ft into rock) 11 CPTs, including 3 seismic CPTs Geophysical testing of 3 boreholes, including:
- Suspension P-S Velocity Logging (p-wave and s-wave velocity measurements)
- Caliper/Natural Gamma Measurements
- Resistivity/Spontaneous Potential Measurements
- Boring Deviation Measurements 15 new ground water observation wells (10 above and 5 below the Blue Bluff Marl)
Laboratory testing 29
General Subsurface Profile Coastal Plain Sediments Q Upper sand stratum-Barnwell Group:
X Depth ranging from 78 to 154 ft-Average of 94 ft X Very loose to very dense Blue Bluff marl stratum - Lisbon Formation:
X Thickness ranging from 63 to 95 ft (3 boreholes)-About 76 ft average thickness X Very hard, slightly sandy, cemented, calcareous silt/clay Q Lower sand strata-Coastal Plain Deposits; X Dense sands X Thickness of 900 ft (at B-1003)
Q Dunbarton Triassic Basin Bedrock (1,049 ft below grade at B-1003)
Q Ground water elevation is 165 ft (55-60 ft below grade) 30
0 Upper Sands Blue Bluff Marl 200 Near-Far Receivers, Vs Coastal Near-Far Receivers, Vp Plain Deposits 400 S-wave and 600 P-wave Velocity DEPTH (ft)
Measurements 800 Borehole B-1003 Receiver to Receiver Vs and Vp Analysis 1000 Dunbarton 1200 Triassic Basin 1400 0 5000 10000 15000 20000 VELOCITY (ft/s) 31
Construction Excavation The upper sands - Barnwell Group:
Q Have highly variable density along the depth and from borehole to borehole Q A shelly, very porous material was encountered at the bottom of the Barnwell Group/top of Blue Bluff Marl that caused severe drilling fluid losses Q These soils were completely removed and replaced with compacted granular fill for construction of existing Units 1 and 2.
Q For these reasons, these soils will be removed 32
Preliminary Powerblock Excavation Plan 785 385 1725 2125 33
Cross Section Normal to PBF Grade EL. 220 MSL Marl B-1004 B-1002 Cretaceous-Tertiary Coastal Plain Deposits B-1003 Paleozoic Crystalline Basement Bedrock Triassic Basin Bedrock 34
Summary of Seismic Hazard at Vogtle Risk Engineering, Inc.
Robin K. McGuire NRC Meeting, Rockville April 14, 2006 35
Steps taken to meet RG1.165
- Effect of additional seismicity, 1985 through mid-2005
- Update of EPRI-SOG seismic sources to account for new source information
- Update of EPRI-SOG ground motion models (using EPRI 2004)
Replication of EPRI-SOG hazard at Vogtle 2005 85%
1E-2 Ann. Freq. Exceedance.
EPRI-SOG 85%
1E-3 2005 mean 1E-4 EPRI-SOG mean 1E-5 2005 median EPRI-SOG 1E-6 median 10 100 1000 PGA, cm/s^2 37
Historical Earthquakes 38
Comparison of catalog seismicity for triangular source
.01 Annual freq. of exceed.
.001 Triangular source thru 1984
.0001 Triangular source thru 2004
.00001 4.5 5.5 6.5 7.5 magnitude (mb) 39
Updated Charleston Seismic Source
- Logic Tree -
40
Updated Charleston Seismic Source (UCSS) 41
Seismic hazard from Charleston, 1 Hz 1E-2 Annual freq. exceedance 1E-3 A
1E-4 B 1E-5 BP 1E-6 C Total 1E-7 1E-8 0.01 0.1 1.
1 Hz SA, g 42
Deaggregation of 1Hz, 5E-5 hazard 43
Deaggregation of 10Hz, 5E-5 hazard 44
Mean rock UHS, 2006 results Rock mean UHS, Vogtle 10.
Spectral Acceleration, g.
Frequency, Hz 45
Hazard comparison for Vogtle: 2006 results and EPRI-SOG Comparison of mean rock UHS results 10.
Spectral acceleration, g.
2006 1E-5 EPRI-SOG
Frequency, Hz 46
Calculation of soil hazard
- Develop soil profile with properties
- Determine soil amplitudes for multiple rock input amplitudes (frequencies from 100 Hz to 0.1 Hz) (1D SHAKE analysis) using M and R from deaggregation (high- and low-frequency spectra)
- Convolve rock hazard with site amplification (including uncertainties in input motion and soil properties) to obtain soil UHS for multiple annual frequencies (NUREG/CR-6728 Approach 2A)
- Develop vertical spectra using V/H ratios (NUREG/CR-6728) 47
Illustrative cross-section at location of new units B-1003 Coastal Plain Sediments Fault Tip Crystalline Basement Triassic Basin Rock Rock 48
Shear-wave velocity measurements at Vogtle and SRS B-1003: R1-R2 0
500 1000 Bottom of Coastal Plain 1500 DRB-11 shifted Depth (ft) 2000 DRB-10 shifted DRB-9 shifted 2500 R1-R2: shallow R1-R2: deep 3000 1050 ft 9,200 ft/sec 3500 Rock Velocity Picks Slope 0.6 4000 Slope 0.9 Slope 1.3 4500 0 2000 4000 6000 8000 10000 12000 Shear-Wave Velocity (ft/sec) 49
Determination of SSE Ground Motion Risk Engineering, Inc.
Robin K. McGuire NRC Meeting, Rockville April 14, 2006 50
Definition of SSE
- SSE is defined here as the site-specific, risk-informed, response spectrum that represents the ground motion that meets regulatory criteria.
- The SSE is a free-field ground motion defined at a specified control point.
- The SSE will subsequently be modified by structure-specific analyses (accounting for foundation size, etc) to define a Design Response Spectrum (DRS) 51
Method for calculating Vogtle SSE
- Risk (performance-goal) based approach is aimed at achieving a Seismic Core Damage Frequency (SCDF) less than a target SCDF goal.
- The target SCDF goal is the industry-proposed value of mean 5E-6/yr (Ref: NEI letter, Heymer to Imbro dated 3/30/06)
- Table 2.2 of NUREG 1742 summarizes existing plant seismic PRA results using EPRI-type hazard curves; overall results:
- Median value 1.2E-5/yr
- Mean value 2.5E-5/yr
- SSE response spectrum will be defined to meet this target goal.
52
Control point for Vogtle ESP SSE
- Per SRP 3.7.1 and 3.7.2: for profiles consisting of one or more thin soil layers overlaying competent material, the control motion should be located at an outcropat the top of the competent material.
- Approximately 90 of existing soil above the Blue Bluff marl unit will be removed and replaced with engineered backfill.
- Therefore, the SSE will be specified at the top of the Blue Bluff marl unit.
53
Plans for AP1000 / Vogtle Site Assessment Don Moore Consulting Engineer Southern Nuclear Operating Company
Plans for AP1000 Assessment
- Exchange of information started with Westinghouse AP1000 soil site parameters Vogtle site soil conditions
- Monitor Westinghouse/NRC interactions on soil technical report APP-GW-GLR-015, Extension of Nuclear Island Seismic Analyses to Soil Sites
- Perform evaluations to demonstrate Vogtle site compatibility with AP1000 design 55
Summary of Key Points
- Purpose of seismic survey was to identify rock type/profile below ESP site
- Using EPRI-SOG seismic hazard model with update of Charleston Seismic Source
- Developing site transfer functions using NUREG/CR-6728 method 2A
- Defining control point of SSE at top of competent material (Blue Bluff Marl)
Discussion 57