ML14177A086

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NRC Presentation Slides for Public Meeting with Southern on Seismic Reevaluation (GMRS)
ML14177A086
Person / Time
Site: Hatch  Southern Nuclear icon.png
Issue date: 06/26/2014
From:
Office of Nuclear Reactor Regulation
To:
Balazik M, NRR/JLD, 415-2856
References
Download: ML14177A086 (21)
v • d • e


Text

Near-term Task Force Recommendation 2 1 Seismic Recommendation 2.1 Seismic Hazard Evaluation Southern June 26, 2014

References for Meeting References for Meeting

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  • Meeting Feedback Form (request from mfb@nrc.gov)
  • May 9, 2014, NRC letter regarding Seismic Screening and Prioritization Results for central and eastern US Licensees (ML14111A147)
  • May 21, 2014, NRC memo providing preliminary staff ground motion response spectra for central and ground motion response spectra for central and eastern Licensees (ML14136A126)
  • Meeting Summary to be issued within 30-day

Meeting Introduction Meeting Introduction

Purpose:

support information exchange and begin dialog to have d

di f h f h i

diff common understanding of the causes of the primary differences between the preliminary NRC and licensee seismic hazard results

Background:

NRC and licensee seismic hazard require resolution

Background:

NRC and licensee seismic hazard require resolution to support a final seismic screening decision and to support related follow-on submittals Outcomes:

  • Begin NRC and licensee resolution to support regulatory decisions and development of seismic risk evaluations, as decisions and development of seismic risk evaluations, as appropriate
  • Establish resolution path, including timelines and identification of potential information needs

Look-ahead:

l Potential Next Steps

  • NRC will consider the meeting information NRC will consider the meeting information
  • Potential paths:

Li b it l

t l i f ti b

d

- Licensee submits supplemental information based on public meeting dialog NRC staff issues a request for information

- NRC staff issues a request for information

- Licensee sends a revision or supplement to the seismic hazard report seismic hazard report

  • NRC completes screening review and issues th fi l

i d t i

ti l tt the final screening determination letter

Hatch Units Nuclear Plant Hatch Units Nuclear Plant Sarah Tabatabai Office of Research Office of Research June 26, 2014

Screening Screens in: Expedited Approach, Seismic Risk, High Frequency, SFP Evaluations P i iti ti G

2 Prioritization Group: 2 0.6 Licensee SSE (Unit 1)

Licensee SSE (Unit 2) 0.4 0.5 tion (g)

(

)

Licensee GMRS NRC GMRS (Updated) 0 2 0.3 ctral Accelera 0.1 0.2 Spec 0

0.1 1

10 100 Frequency (Hz)

Stratigraphy Site Geologic Column (Source: FSAR Figure 2.5-8, Rev. 19)

Control Point Control Point NRC SSE Control Point El. 129 ft Submittal SSE Control Point El. 129 ft SS Co o

o 9

SS Co o

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Vs Profile Development Vs Profile Development NRC Template velocity profile for Submittal ISFSI data used to develop near Template velocity profile for Vs=400 m/s (1312 ft/sec) from SPID used for entire profile.

Template velocity profile supported ISFSI data used to develop near surface Vs profile (i.e. to a depth of 229 ft). Deeper portions of the profile (i.e. below a depth of 509 ft) by Vs data found in the literature were developed with nearby oil well exploration (Vp) data

Epistemic Uncertainty in Vs Profiles Profiles NRC Applied a scale factor of 1.2 to the Submittal Applied a scale factor of 1.57 to the pp ed a sca e ac o o o

e base case profile for development of the upper and lower case profiles pp ed a sca e ac o o 5

o e

base case profile for development of the upper and lower case profiles

Vs Profiles Shear-Wave Velocity (ft/sec) 0 500 0

2000 4000 6000 8000 10000 12000 y (

)

0 50 0

2000 4000 6000 8000 Shear-Wave Velocity (ft/sec)

NRC-BC NRC-LBC 1000 1500 t) 50 100 150 NRC-UBC Licensee-BC Licensee-LBC Licensee-UBC 1500 2000 2500 ontrol Point (ft 150 200 ntrol Point (ft) 2500 3000 epth Below Co 250 300 pth Below Con 3500 4000 De NRC-BC NRC-LBC NRC-UBC 350 400 Dep 4500 5000 NRC UBC Licensee-BC Licensee-LBC Licensee-UBC 450 500

0 0

2000 4000 6000 8000 10000 Shear-Wave Velocity (ft/sec)

Hawthorn Fm.

T F

Vs=2450 +/-200 ft/s in upper 50-100 ft (FSAR)

Information from other sites:

Saxena (2008) Vs=1500 -

1900 ft/s (Hawthorn Fm )

500 1000 Tampa Fm.

Undifferentiated Oligocene Ocala Fm.

Vogtle COL: Vs=2650 ft/s Parker (2008) Vs=2296 ft/s (Ocala Fm.)

1900 ft/s (Hawthorn Fm.)

1500 nt (ft)

Lisbon Fm.

Tallahata Fm.

Wilcox Group Clayton Fm.

at 149 ft (Lisbon Fm.)

Odum et al (2003):

Vs=2805 ft/s at 98 ft (Wilcox Group) 2000 2500 w Control Poin Post Tuscaloosa Deposits (Wilcox Group) 3000 3500 Depth Below Tuscaloosa Fm.

Odum et al (2003):

Vs=2840 ft/s at 98 ft 3500 4000 NRC-BC Undifferentiated Early Cretaceous Deposits (Tuscaloosa Fm.)

4500 5000 NRC-LBC NRC-UBC Licensee-BC Pre-Cretaceous Basement Rock

0 0

2000 4000 6000 8000 10000 Shear-Wave Velocity (ft/sec) 500 1000 An average Poissons ratio of 1500 nt (ft)

Lisbon Fm.

g 0.43 is reported for the Lisbon Formation at the Farley site 2000 2500 w Control Poi NRC-BC NRC-LBC 3000 3500 Depth Belo NRC-UBC Licensee-BC (v=0.25)

Licensee-BC (v=0.33) 4000 Licensee-BC (v=0.45) 4500 5000

Aleatory Uncertainty in Vs Profiles NRC S b itt l NRC 60 Randomizations Using USGS B Site Conditions Submittal 30 Randomizations Using USGS B C and D Site Conditions for B Site Conditions B, C, and D Site Conditions for the Upper-Range, Median, and Lower-Range Profiles, Respectively ln = 0.25 Upper 50 ft.

ln = 0.15 Below 50 ft.

ln = 0.25 Upper 90 ft.

ln = 0.15 Below 90 ft.

Epistemic Uncertainty in Shear Modulus and Damping Curves Modulus and Damping Curves NRC M1 Submittal M1 M1 EPRI Soil: 0 - 276 ft EPRI Rock: 276 - 500 ft Linear & No Damping: > 500 ft M1 Av. of EPRI 50-120 ft & 120-250 ft:

0 - 129 ft Av. of EPRI 120-250 ft & 250-500 ft:

p g M2 Peninsular: 0 - 276 ft Linear & 1% Damping: 276 500 ft 129 - 279 ft Idriss & Boulanger Weathered Rock Curves: 279 to 509 ft Linear & Kappa Based Damping: >

Linear & 1% Damping: 276 - 500 ft Linear & No Damping: > 500 ft Linear & Kappa-Based Damping: >

500 ft

Kappa and Epistemic Uncertainty NRC Kappa was calculated for each Submittal Calculated a kappa distribution2 for Kappa was calculated for each base case profile using Q values from Campbell (2009). A ln=0.2 was applied to determine the range Calculated a kappa distribution2 for each base case Vs profile based on a median kappa of 0.04 sec (i.e. a deep soil site) and a ln=0.4 of kappas for each base case profile.

Base Case Kappas LBC: 0 0571 Kappa Distribution kL: 0 024 LBC: 0.057 BC: 0.040 UBC: 0.030 kL: 0.024 kM: 0.040 kU: 0.067 1Imposed an upper limit of 0.04 sec based on the SPID Guidance 2Clarification needed

Amplification Functions p

5 6

NRC (Input PGA = 0.01 g)

NRC (Input PGA = 0.2 g)

NRC (Input PGA = 0.5 g)

Licensee (Input PGA = 0.01 g) 3 4

fication Licensee (Input PGA = 0.2 g)

Licensee (Input PGA = 0.5 g)

NRC Sigma (Input PGA = 0.01 g)

NRC Sigma (Input PGA = 0.2 g)

NRC Sigma (Input PGA = 0.5 g)

Licensee Sigma (Input PGA = 0.01 g) 2 3

Amplif Licensee Sigma (Input PGA = 0.2 g)

Licensee Sigma (Input PGA = 0.5 g) 0 1

0.1 1

10 100 Frequency (Hz)

GMRS Comparison 1

0.1 tion (g) ectral Accelerat NRC GMRS 0.01 Spe Licensee GMRS Hatch Unit 2 SSE Hatch Unit 1 SSE 0.001 0.1 1

10 100 Frequency (Hz)

Licensee GMRS (NRC Calc.)

Primary Differences Primary Differences

  • Kappa

- Southern considered Hatch to be a deep soil site and used a median kappa of 0.04 sec, while the NRC placed an upper limit of 0.04 sec on kappa Classification as a deep soil site inconsistent with Vs

- Classification as a deep soil site inconsistent with Vs base cases

  • Large differences in shear-wave velocities Large differences in shear wave velocities below a depth of approximately 500 ft due to an assumed Poissons ratio to an assumed Poisson s ratio
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