ML070670331
| ML070670331 | |
| Person / Time | |
|---|---|
| Site: | Harris, Bellefonte, PROJ0740  |
| Issue date: | 03/01/2007 |
| From: | Progress Energy Carolinas |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| +reviewedjms3 | |
| Download: ML070670331 (20) | |
Text
1 Progress Energy Harris Site Status NuStart-NEI Seismic Workshop March 1, 2007
2 Harris Project Summary
- Two new AP1000 Units (HAR 2 and HAR
- 3) are planned adjacent (North) of HNP Unit 1
- Site Investigation performed April through December 2006
- COLA submittal in late 2007
3 Harris Site Location
4 Harris Location of New Units HAR 3 HAR 2 South
5 Harris Geotechnical Boring Layout SiteView NI
6 Harris Geotechnical Investigation Summary 4 Pairs of Profiles (depth < 100 ft)
SASW Surveys (Vs) 5 Profiles (depth < 70 ft)
MASW Surveys (Vs) 2 Boreholes (~200 ft depth)
Downhole Logging (Vp and Vs) 7 Boreholes (~150-200 ft depth)
P-S Suspension Logging (Compression and shear wave velocity [Vp and Vs])
~3200 Feet Seismic Refraction Surveys (Vp) 20 Groundwater Monitoring Wells
-50 at AP1000 Structures
-18 General Characterization
-15 at CTs and Conveyance Soil & Rock Borings
7 Harris Existing Subsurface Profile (Typical)
HAR-3 HAR-2 5 - 20 0 - 10 0 - 10 15 - 40 Top of Sound Rock 10 - 25 Top of Weathered Rock -
Transition Zone from Residual Soil to Sound Rock 0 - 25 Residual Soils - Reddish Brown.
Typically lean clays (CL), sandy silts (ML) and silty sand (SM)
8 Harris - Unit 2 Fence Diagram with S-Wave Velocity Profiles
9 Harris - Unit 3 Fence Diagram with S-Wave Velocity Profiles
10 Harris - Unit 2 - S-Wave Velocity Profiles - Adjusted Elevations
11 Harris - Unit 3 - S-Wave Velocity Profiles - Adjusted Elevations
12 Harris Rock Shear Wave Velocity
- Shear Wave Velocity (VS) below Reactor Island Basemat Elevation (220 feet above MSL) -
based on 7 suspension logging profiles to depth of ~200 feet bgs.
Standard Deviation Average Vs (fps)
Unit 981 6,079 HAR-3 779 6,227 HAR-2
13 Harris Preliminary Construction Plans
- Plant Site Grades
- Establish Plant Grade at Elevation = 260 feet.
- Establish Nuclear Island Basemat Subgrade on Competent Rock at Elevation = 220 feet.
- Nuclear Island:
- HAR-2: Rock Excavation (~1H:2V) to basemat subgrade.
- HAR-3: Plan to excavate as soil (~2H:1V) to basemat subgrade.
Overexcavate clay seams at basemat subgrade, backfill/grout with concrete fill.
- Other Structures:
- HAR-2: Excavate to Competent Rock and place Engineered Backfill (typically only 5 to 10 feet needed).
- HAR-3: Overexcavate and place Structural Backfill (up to 30 feet needed), OR construct deep foundations (caissons). To be finalized during detailed design.
14 Harris Site Seismicity
- Site sits in a region of relatively low seismicity
~ 100 km contribute to site hazard Charleston East Tennessee Central Virginia Harris Site Giles County
15 Harris Regional Physiographic Setting
16 Harris Site PSHA
- Use UCSS (Vogtle) update of Charleston seismic source
- Overlay reoccurring Charleston mb > ~6.5 earthquakes
- Limit Mmax to mb 6.5 for EPRI-SOG Charleston sources to prevent double counting
- Use EPRI-SOG expert team assessments for all other seismic sources
- No adjustments in rates needed
- Minor adjustments in Mmax and source combinations
17 Harris Site PSHA (Contd)
- Use EPRI (2004) Ground Motion Models
- Use EPRI (2006) (G1.3) Aleatory Variability (Sigma)
- Not expected to produce a large change in hazard
- Implementation will incorporate site response
18 Harris Site Geology
- Site sits in Durham subbasin of the Deep River basin
- Approximately 5,000 ft of Triassic sediments
- Shallow sediments consist of interbedded siltstones and sandstones
- VS 4,000-5000 ft/sec at foundation level, quickly rising to 6,000-7,000 ft/sec
19 Harris Site Response
- Compute amplification of Triassic sediments using NUREG/CR 6728 method 2B
- Shallow velocity profile based on site data to a depth of ~200 ft
- Deeper profile based on nearby deep bore hole and refraction lines
20 Harris Site SSE Ground Motions
- Use performance-based ASCE 43-05 methodology
- Define SSE at outcrop of weathered Triassic rocks - elevation ~250 ft
- Simultaneously compute motions at foundation level - elevation 220 ft