ML14177A086

NRC Presentation Slides for Public Meeting with Southern on Seismic Reevaluation (GMRS)

ML14177A086
Person / Time
Site:	Hatch
Issue date:	06/26/2014
From:	Office of Nuclear Reactor Regulation
To:
Balazik M, NRR/JLD, 415-2856
References
Download: ML14177A086 (21)

Text

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

References for Meeting

• Licensee Presentation Slides - ML14176B239

• NRC Presentation Slides - ML14177A086

• Public Meeting Agenda - ML14169A437

• M ti FFeedback Meeting db k FForm ((requestt ffrom mfb@nrc.gov) fb@ )

• 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 eastern Licensees (ML14136A126)

• Meeting Summary to be issued within 30-day

Meeting Introduction

Purpose:

support information exchange and begin dialog to have common understanding d di off the h causes off the h primary i diff differences between the preliminary NRC and licensee seismic hazard results

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 appropriate

• Establish resolution path, including timelines and identification of potential information needs

Look-ahead:

Potentiall Next Steps

• NRC will consider the meeting information

• Potential paths:

- Licensee Li submits b it supplemental l t l iinformation f ti bbased d

on public meeting dialog

- NRC staff issues a request for information

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

• NRC completes screening review and issues th fi the finall screening i d determination t i ti lletter tt

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

Screening

• Screens in: Expedited Approach, Seismic Risk, High Frequency, SFP Evaluations

• Prioritization P i iti ti G Group: 2 0.6 Licensee SSE (Unit 1)

Licensee SSE ((Unit 2))

0.5 Licensee GMRS NRC GMRS (Updated)

Specctral Acceleration (g) 0.4 0.3 02 0.2 0.1 0

0.1 1 10 100 Frequency (Hz)

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

Control Point NRC Submittal SSE Control SS Co o Point o El. 129 9 ft SSE Control SS Co o Point o El. 129 9 ft

Vs Profile Development NRC Submittal Template velocity profile for ISFSI data used to develop near Vs=400 m/s (1312 ft/sec) from surface Vs profile (i.e. to a depth of SPID used for entire profile. 229 ft). Deeper portions of the Template velocity profile supported 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 NRC Submittal Applied pp ed a sca scale e factor ac o oof 1.2 to o the e Applied pp ed a sca scale e factor ac o oof 1.57 5 to o the e

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

Vs Profiles Shear-Wave Velocity y ((ft/sec))

Shear-Wave Velocity (ft/sec) 0 2000 4000 6000 8000 10000 12000 0 2000 4000 6000 8000 0 0

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

Information from other sites: Shear-Wave Velocity (ft/sec) 0 2000 4000 6000 8000 10000 Vs=2450 +/-200 ft/s in upper 0 50-100 ft (FSAR) Saxena (2008) Vs=1500 - Hawthorn Fm.

1900 ft/s (Hawthorn Fm.)

Fm ) TTampa FFm.

500 Undifferentiated Oligocene Parker (2008) Vs=2296 ft/s Ocala Fm.

(Ocala Fm.)

Vogtle COL: Vs=2650 ft/s 1000 at 149 ft (Lisbon Fm.) Lisbon Fm.

Odum et al (2003): 1500 Tallahata Fm.

Wilcox Group Depth Below w Control Poin nt (ft)

Vs=2805 ft/s at 98 ft (Wilcox Group) Clayton Fm.

2000 2500 Post Tuscaloosa Deposits 3000 Odum et al (2003):

Vs=2840 ft/s at 98 ft Tuscaloosa Fm.

3500 (Tuscaloosa Fm.)

4000 Undifferentiated Early NRC-BC Cretaceous Deposits NRC-LBC 4500 Pre-Cretaceous NRC-UBC Basement Rock Licensee-BC 5000

Shear-Wave Velocity (ft/sec) 0 2000 4000 6000 8000 10000 0

500 An averageg Poissons ratio of 1000 Lisbon Fm.

0.43 is reported for the Lisbon Formation at the 1500 Depth Below Control Point (ft)

Farley site 2000 NRC-BC 2500 NRC-LBC NRC-UBC 3000 Licensee-BC (v=0.25)

Licensee-BC (v=0.33) 3500 Licensee-BC (v=0.45) 4000 4500 5000

Aleatory Uncertainty in Vs Profiles NRC S b itt l Submittal 60 Randomizations Using USGS 30 Randomizations Using USGS B Site Conditions B C, B, C and D Site Conditions for the Upper-Range, Median, and Lower-Range Profiles, Respectively ln = 0.25 Upper 50 ft. ln = 0.25 Upper 90 ft.

ln = 0.15 Below 50 ft. ln = 0.15 Below 90 ft.

Epistemic Uncertainty in Shear Modulus and Damping Curves NRC Submittal M1 M1 EPRI Soil: 0 - 276 ft Av. of EPRI 50-120 ft & 120-250 ft:

EPRI Rock: 276 - 500 ft 0 - 129 ft Linear & No Damping:

p g > 500 ft Av. of EPRI 120-250 ft & 250-500 ft:

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

Linear & No Damping: > 500 ft 500 ft

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

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

Amplification p Functions 6

NRC (Input PGA = 0.01 g)

NRC (Input PGA = 0.2 g)

NRC (Input PGA = 0.5 g) 5 Licensee (Input PGA = 0.01 g)

Licensee (Input PGA = 0.2 g)

Licensee (Input PGA = 0.5 g) 4 NRC Sigma (Input PGA = 0.01 g)

NRC Sigma (Input PGA = 0.2 g)

Ampliffication NRC Sigma (Input PGA = 0.5 g)

Licensee Sigma (Input PGA = 0.01 g) 3 Licensee Sigma (Input PGA = 0.2 g)

Licensee Sigma (Input PGA = 0.5 g) 2 1

0 0.1 1 10 100 Frequency (Hz)

GMRS Comparison 1

Spe ectral Accelerattion (g) 0.1 NRC GMRS 0.01 Licensee GMRS Hatch Unit 2 SSE Hatch Unit 1 SSE Licensee GMRS (NRC Calc.)

0.001 0.1 1 10 100 Frequency (Hz)

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 base cases

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