GNRO-2014/00027, Entergy Seismic Hazard and Screening Report (CEUS Sites), Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi.

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Entergy Seismic Hazard and Screening Report (CEUS Sites), Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi.
ML14090A098
Person / Time
Site: Grand Gulf Entergy icon.png
Issue date: 03/31/2014
From: Kevin Mulligan
Entergy Operations
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
GNRO-2014/00027
Download: ML14090A098 (43)
v • d • e


Text

Entergy Operations, Inc.

P. O. Box 756 Port Gibson, MS 39150 Kevin Mulligan Site Vice President Grand Gulf Nuclear Station Tel. (601) 437-7400 GNRO-2014/00027 March 31,2014 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001

SUBJECT:

. Entergy Seismic Hazard and Screening Report (CEUS Sites), Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident Grand Gulf Nuclear Station, Unit 1 Docket No. 50-416 License No. NPF-29

REFERENCES:

1. NRC Letter, Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Recommendations 2.1, 2.3, and 9.3, of the Near- Term Task Force Review of Insights from the Fukushima Dai-ichi Accident, dated March 12,2012
2. NEI Letter, Proposed Path Forward for NTTF Recommendation 2. 1:

Seismic Reevaluations, dated April 9, 2013, ADAMS Accession No. ML13101A379

3. NRC Letter, Electric Power Research Institute Final Draft Report XXXXXX, "Seismic Evaluation Guidance: Augmented Approach for the Resolution of Fukushima Near- Term Task Force Recommendation 2.1:

Seismic, " as an Acceptable Alternative to the March 12, 2012, Information Request for Seismic Reevaluations, dated May 7, 2013, ADAMS Accession No. ML13106A331

4. EPRI Report 1025287, Seismic Evaluation Guidance, Screening, Prioritization and Implementation Details (SPID) for the Resolution of Fukushima Near- Term Task Force Recommendation 2. 1: Seismic, ADAMS Accession No. ML12333A170
5. NRC Letter, Endorsement of EPRI Final Draft Report 1025287, "Seismic Evaluation Guidance, " dated February 15, 2013, ADAMS Accession No. ML12319A074
6. Entergy letter to NRC, Entergy's Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding the Seismic Aspects of Recommendation 2. 1 of the Near- Term Task Force Review of Insights from the Fukushima Dai-ichi Accident - 1.5 Year Response for CEUS Sites, dated September 12, 2013, ADAMS Accession No. ML13254A311, GNRO-2013/00068

GNRO-2014/00027 Page 2 of 3

Dear Sir or Madam:

On March 12, 2012, the Nuclear Regulatory Commission (NRC) issued Reference 1 to all power reactor licensees and holders of construction permits in active or deferred status. Enclosure 1 of Reference 1 requested each addressee located in the Central and Eastern United States (CEUS) to submit a seismic hazard evaluation within 1.5 years from the date of Reference 1.

In Reference 2, the Nuclear Energy Institute (NEI) requested NRC agreement to delay submittal of the final CEUS seismic hazard evaluation so that an update to the Electric Power Research Institute (EPRI) ground motion attenuation model could be completed and used to develop that information. NEI proposed that descriptions of subsurface materials and properties and base case velocity profiles be submitted to the NRC by September 12, 2013 (Reference 6), with the remaining seismic hazard and screening information submitted by March 31,2014. NRC agreed with that proposed path forward in Reference 3.

Reference 4 contains industry guidance and detailed information to be included in the Seismic Hazard Evaluation and Screening Report submittals. NRC endorsed this industry guidance in Reference 5.

The attached Seismic Hazard Evaluation and Screening Report for Grand Gulf Nuclear Station Unit 1 (GGNS) provides the information described in Section 4 of Reference 4 in accordance with the schedule identified in Reference 2.

This letter contains no new regulatory commitments.

If you have any questions or require additional information, please contact Jeffery A.

Seiter at 601-437-2344.

I declare under penalty of perjury that the foregoing is true and correct. Executed on March 31, 2014.

Sincerely, L __

~~--...

KJM/jas 2:::::::--

Attachment:

GGNS Seismic Hazard and Screening Report (CEUS Sites) cc: (see next page)

GNRO-2014/00027 Page 3 of 3 cc: Mr. Marc L. Dapas Regional Administrator, Region IV U. S. Nuclear Regulatory Commission 1600 East Lamar Boulevard Arlington, TX 76011-4511 U. S. Nuclear Regulatory Commission Attn: Director, Office of Nuclear Reactor Regulation One White Flint North Washington, DC 20555-0001 U. S. Nuclear Regulatory Commission ATTN: Mr. A. Wang, NRR/DORL Mail Stop OWFN/8 G14 Washington, DC 20555-0001 NRC Senior Resident Inspector Grand Gulf Nuclear Station Port Gibson, MS 39150

Attachment to GNRO-2014/00027 GGNS Seismic Hazard and Screening Report (CEUS Sites)

Seismic Hazard and Screening Report for Grand Gulf Nuclear Station

Table of Contents Page 1.0 Introduction 2 2.0 Seismic Hazard Reevaluation 3 2.1 Regional and Local Geology 4 2.2 Probabilistic Seismic Hazard Analysis 4 2.2.1 Probabilistic Seismic Hazard Analysis Results 4 2.2.2 Base Rock Seismic Hazard Curves 6 2.3 Site Response Evaluation 6 2.3.1 Description of Subsurface Material 6 2.3.2 Development of Base Case Profiles and Nonlinear Material Properties 9 2.3.2.1 Shear Modulus and Damping Curves 12 2.3.2.2 Kappa 12 2.3.3 Randomization of Base Case Profiles 13 2.3.4 Input Spectra 13 2.3.5 Methodology 14 2.3.6 Amplification Functions 14 2.3.7 Control Point Seismic Hazard Curves 19 2.4 Ground Motion Response Spectrum 20 3.0 Plant Design Basis and Beyond Design Basis Evaluation Ground Motion 21 3.1 SSE Description of Spectral Shape 22 3.2 Control Point Elevation 22 3.3 IPEEE Description and Capacity Response Spectrum 23 4.0 Screening Evaluation 23 4.1 Risk Evaluation Screening (1 to 10 Hz) 23 4.2 High Frequency Screening (>10 Hz) 23 4.3 Spent Fuel Pool Evaluation Screening (1 to 10Hz) 23 5.0 Interim Actions 23 6.0 Conclusions 24 7.0 References 25 Appendix A 27 1

1.0 Introduction Following the accident at the Fukushima Daiichi nuclear power plant resulting from the March 11,2011, Great Tohoku Earthquake and subsequent tsunami, the Nuclear Regulatory Commission (NRC) established a Near-Term Task Force (NTTF) to conduct a systematic review of NRC processes and regulations and to determine if the agency should make additional improvements to its regulatory system. The NTTF developed a set of recommendations intended to clarify and strengthen the regulatory framework for protection against natural phenomena. Subsequently, the NRC issued a 50.54(f) letter (U.S. NRC, 2012) that requests information to assure that these recommendations are addressed by all U.S.

nuclear power plants. The 50.54(f) letter (U.S. NRC, 2012) requests that licensees and holders of construction permits under 10 CFR Part 50 reevaluate the seismic hazards at their sites against present-day NRC requirements. Depending on the comparison between the reevaluated seismic hazard and the current design basis, the result is either no further risk evaluation or the performance of a seismic risk assessment. Risk assessment approaches acceptable to the staff include a Seismic Probabilistic Risk Assessment (SPRA), or a Seismic Margin Assessment (SMA). Based upon the risk assessment results, the NRC staff will determine whether additional regulatory actions are necessary.

This report provides the information requested in items (1) through (7) of the "Requested Information" section and Attachment 1 of the 50.54(f) letter (U.S. NRC, 2012) pertaining to NTTF Recommendation 2.1 for the Grand Gulf Nuclear Station (GGNS), located in Claiborne County, Mississippi. In providing this information, Entergy followed the guidance provided in the Seismic Evaluation Guidance: Screening, Prioritization, and Implementation Details (SPID) for the Resolution of Fukushima Near- Term Task Force Recommendation 2.1: Seismic (EPRI, 2013a). The Augmented Approach, Seismic Evaluation Guidance: Augmented Approach for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic (EPRI, 2013b),

has been developed as the process for evaluating critical plant equipment as an interim action to demonstrate additional plant safety margin prior to performing the complete plant seismic risk evaluations.

The original geologic and seismic siting investigations for GGNS were performed in accordance with Appendix A to 10 CFR Part 100 and meet General Design Criterion 2 in Appendix A to 10 CFR Part 50. The Safe Shutdown Earthquake (SSE) Ground Motion was developed in accordance with Appendix A to 10 CFR Part 100 and used for the design of seismic Category I systems, structures and components.

In response to the 50.54(f) letter (U.S. NRC, 2012) and following the guidance provided in the SPID (EPRI, 2013a), a seismic hazard reevaluation for GGNS was performed. For screening purposes, a Ground Motion Response Spectrum (GMRS) was developed.

Based on the results of the screening evaluation, no further evaluations will be performed.

2

2.0 Seismic Hazard Reevaluation .

The Grand Gulf Nuclear Station is located in Claiborne County, Mississippi. The plant site is located near the east bank of the Mississippi River, approximately 25 miles south of Vicksburg and 37 miles northeast of Natchez. The community of Grand Gulf is approximately 1-1/2 miles to the north. The town of Port Gibson is about 6 miles southeast of the plant site. This area is in the Loess or Bluff Hills and Mississippi Alluvial Valley subprovinces of the Gulf Coastal Plain physiographic province. The site is underlain by approximately 13,000 ft of Cretaceous and Cenozoic sands, gravels, clays, marls, claystones, sandstones, and limestones. The Catahoula Formation of Miocene age is the foundation-bearing stratum for the major plant structures. It consists primarily of hard-to-very-hard silty-to-sandy clay, clayey silt, and locally indurated or cemented clay, sand and silt layers. (Entergy, 2013)

The site lies within the Gulf Coast Basin tectonic province which is the major geologic and tectonic region along the Gulf Coast. The province is bounded on the north by the Monroe uplift and Jackson dome about 60 miles north of the site. The northern most fault zone in the province is the Baton Rouge fault zone, located 110 miles south of the site. No seismic activity has been recorded on the Baton Rouge fault zone. (Entergy, 2013)

Infrequent earthquakes have occurred randomly in this province; however, they are not known to be associated with any specific geologic structure. Faults in the Gulf Coast Basin originate, so far as is known, within the sedimentary pile, and, therefore, resemble large-scale slumping more than tectonic faulting. Lack of any known association with earthquakes indicates these faults are not potential sources of vibratory ground motion large enough to be of engineering concern. The maximum historical intensity in the tectonic province is intensity VI on the Modified Mercalli Intensity Scale of 1931, which was recorded near Donaldsonville, Louisiana, about 140 miles south of the site. (Entergy, 2013)

The Mississippi Embayment tectonic province is a structurally distinct region in the central Mississippi Valley area. It extends from the Monroe uplift and Jackson dome northward to southern Illinois. The closest approach of the Mississippi Embayment tectonic province is about 60 miles north of the site. Within this province, the New Madrid fault zone, which trends south-southwest from the head of the Mississippi Embayment, possibly as far south as about 15 miles northwest of Memphis, offsets embayment sediments and is considered capable. Detailed investigations have established that the fault zone does not extend farther south than Memphis, Tennessee, 220 miles north of the site. South of Memphis scarcely any seismic activity has been recorded. Therefore, there is no reason to assume that the maximum event associated with the New Madrid seismic zone (Intensity XII on the Modified Mercalli Intensity Scale of 1931) could occur south of Memphis, Tennessee. Further study indicates that no other earthquakes associated with either the Mississippi Embayment or the Gulf Coast tectonic province, or any other tectonic province, are as important to the site as are the New Madrid or Donaldsonville earthquakes. Also, no surface faults exist within 5 miles of the site. Consequently, based on the seismicity of both the Gulf Coast Basin tectonic province and Mississippi Embayment 3

tectonic province (New Madrid seismic zone), the SSE is conservatively selected at 0.15g at foundation grade on the Catahoula Formation. (Entergy, 2013)

2. 1 Regional and Local Geology The Grand Gulf Nuclear Station is located near the east bank of the Mississippi River in Claiborne County, Mississippi. The site is located within an extensive structural and depositional province known as the Gulf Coast Basin. The sediments contained within the basin form the subdued terrain that is characteristic of the Gulf Coastal Plain physiographic province, which includes nearly all of the region within 200 miles of the site. The basin is filled by a series of sedimentary formations composed chiefly of fine sand, silt, clay, marl, limestone and chalk, which range in age from Jurassic to Holocene and are mainly unconsolidated. (Entergy, 2013)

In the site region, two major tectonic provinces, the Gulf Coast Basin and Mississippi Embayment tectonic provinces, occur within the Gulf Coastal Plain. The site is located in the Gulf Coast Basin tectonic province. The northern boundary of the province corresponds approximately with the latitude of the northern flanks of the Monroe uplift and Jackson dome.

To the west and east, the northern boundary of the province is assumed to occur at the landward limits of exposed Upper Cretaceous strata. The Gulf Coast Basin merges with the Atlantic Coastal Plain in south Georgia and Florida. (Entergy, 2013)

The Mississippi Embayment tectonic province extends northward from the Monroe uplift and Jackson dome into southern Illinois. The province corresponds to the region flanking the Mississippi River covered by Cenozoic sediments. The structural grain is generally northeast-southwest, although several major buried features trend northwest-southeast. (Entergy, 2013)

There is no evidence to suggest that surficial or subsurface materials at the site have been affected by prior earthquake activity. No faults were encountered by the numerous site borings

  • or exposed in any of the excavations. (Entergy, 2013)

The depth to the Paleozoic basement bedrock at the site is reportedly 13,000 ft. The materials above the basement surface are not welliithified and can be expected to yield plastically to any applied stress. No evidence of stresses in the overlying materials was discovered during the investigation of the site or the surrounding area. (Entergy, 2013) 2.2 Probabilistic Seismic Hazard Analysis 2.2. 1 Probabilistic Seismic Hazard Analysis Results In accordance with the 50.54(f) letter (U.S. NRC, 2012) and following the guidance in the SPID (EPRI, 2013a), a Probabilistic Seismic Hazard Analysis (PSHA) was completed using the recently developed Central and Eastern United States Seismic Source Characterization (CEUS-SSC) for Nuclear Facilities (CEUS-SSC, 2012) together with the updated Electric Power Research Institute (EPRI) Ground-Motion Model (GMM) for the Central and Eastern United 4

States (CEUS) (EPRI, 2013c). For thePSHA, a lower-bound moment magnitude of 5.0 was used, as specified in the 50.54(f) letter (U.S. NRC, 2012). (EPRI, 2014)

For the PSHA, the CEUS-SSC background seismic sources out to a distance of 400 miles (640 km) around GGNS were included. This distance exceeds the 200 mile (320 km) recommendation contained in Reg. Guide 1.208 (U.S. NRC, 2007) and was chosen for completeness. Background sources included in this site analysis are the following (EPRI, 2014):

1. Extended Continental Crust-Atlantic Margin (ECC_AM)
2. Extended Continental Crust-Gulf Coast (ECC_GC)
3. Gulf Highly Extended Crust (GHEX)
4. Mesozoic and younger extended prior - narrow (MESE-N)
5. Mesozoic and younger extended prior - wide (MESE-W)
6. Midcontinent-Craton alternative A (MIDC_A)
7. Midcontinent-Craton alternative B (MIDC_B)
8. Midcontinent-Craton alternative C (MIDC_C)
9. Midcontinent-Craton alternative D (MIDC_D)
10. Non-Mesozoic and younger extended prior - narrow (NMESE-N)
11. Non-Mesozoic and younger extended prior - wide (NMESE-W)
12. Oklahoma Aulacogen (OKA)
13. Paleozoic Extended Crust narrow (PEZ_N)
14. Paleozoic Extended Crust wide (PEZ_W)
15. Reelfoot Rift (RR)
16. Reelfoot Rift including the Rough Creek Graben (RR-RCG)
17. Study region (STUDY_R)

For sources of large magnitude earthquakes, designated Repeated Large Magnitude Earthquake (RLME) sources in NUREG-2115 (CEUS-SSC, 2012) modeled for the CEUS-SSC, the following sources lie within 1,000 km of the site and were included in the analysis (EPRI, 2014):

1. Charleston
2. Commerce
3. Eastern Rift Margin Fault northern segment (ERM-N)
4. Eastern Rift Margin Fault southern segment (ERM-S)
5. Marianna
6. Meers
7. New Madrid Fault System (NMFS)
8. Wabash Valley 5

The Grand Gulf Nuclear Station is located within the gulf region of the CEUS approximately 87 miles (140 km) from the mid-continent region border. For each of the above background sources, the Gulf version of the updated CEUS EPRI GMM are used to model the seismic wave travel path. For the NMFS, Commerce, ERM-N, ERM-S, Marianna, Meers, and Wabash RLMEs, a combination of Gulf (50%) and mid-continent (50%) GMMs are used based on the relative fraction of the seismic wave travel paths through these regions from source to site. For the Charleston RLME source, a combination of Gulf (17%) and mid-continent (83%) GMMs are created based on the relative travel path from the center of the Charleston Local zone to the site. (EPRI, 2014) 2.2.2 Base Rock Seismic Hazard Curves Consistent with the SPID (EPRI, 2013a), base rock seismic hazard curves are not provided as the site amplification approach referred to as Method 3 has been used. Seismic hazard curves are shown below in Section 2.3.7 at the SSE control point elevation.

2.3 Site Response Evaluation Following the guidance contained in Seismic Enclosure 1 of the 50.54(f) Request for Information (U.S. NRC, 2012) and in the SPID (EPRI, 2013a) for nuclear power plant sites that are not founded on hard rock (defined as 2.83 km/sec), a site response analysis was performed for GGNS. (EPRI, 2014) 2.3.1 Description of Subsurface Material The GGNS is located in west-central Mississippi about 25 miles (40 km) south of Vicksburg near the east bank of the Mississippi River in Claiborne County. This area is in the Loess or Bluff Hills and Mississippi Alluvial Valley subprovinces or the Gulf Coastal Plain physiographic province. The site is underlain by approximately 13,000 ft (4,000 m) of Cretaceous and Cenozoic sands, gravels, clays, marls, claystones, sandstones, and limestones Precambrian basement rocks are at a depth of about 27,000 ft (8,200 m). (Entergy, 2013)

The information used to create the site geologic profile at the GGNS is shown in Table 2.3.1-1.

This profile was developed using information documented in (Entergy, 2013). As indicated in Table 2.3.1-1, the SSE Control Point is defined at elevation 87 ft at the top of the Catahoula clay formation.

6

Shear Depth Compression Young's Shear Bulk Elevation Wave Density Poisson's Range Soil Description Wave Modulus Modulus Modulus (feet) Velocity (pcf) Ratio (feet) Velocity (fps) (ksf) (ksf) (ksf)

(fps) 197 to 127 70 Loess - Silt 1,400 670 105 0.35 3,950 1,460 4,390 127 to 107 20 Terrace - Silty Clay 4,600 1,100 119 0.47 13,200 4,470 73,000 107 to 87 20 Terrace - Sand 6,000 1,600 125 0.46 29,000 9,940 121,000 SSE Control Point at 87 -

base mat of structures 87 to 67 20 Catahoula - Clay 6,560 1,600 120 0.47 28,000 9,540 156,000 Catahoula - Clay and 67 to 17 50 Silt with Silty Sand 6,560 1,640 120 0.47 29,500 10,000 164,000 Layers Catahoula - Clay and 17 to -33 50 Silt with Silty Sand 6,400 1,720 120 0.46 32,200 11,000 134,000 Layers Catahoula - Clay and

-33 to -103 70 Silt with Silty Sand 6,730 1,715 120 0.47 32,200 11,000 179,000 Layers 7

The following description of the general geology of the site is taken directly from plant-specific information (Entergy, 2013):

"The Grand Gulf Nuclear Station is located near the east bank of the Mississippi River in Claiborne County, Mississippi, about 25 mi south of Vicksburg and 37 mi northeast of Natchez. [...] This area is in the Loess or Bluff Hills and Mississippi Alluvial Valley subprovinces or the Gulf Coastal Plain physiographic province. The site is underlain by approximately 13,000 ft of Cretaceous and Cenozoic sands, gravels, clays, marls, claystones, sandstones, and limestones."

"The Quaternary sediments in the site vicinity consist of sands, gravels, silts, and clays of Holocene and Pleistocene ages. In the site area, fluvial material occurring within the Mississippi Alluvial Valley and its tributaries, ranges in thickness from 22 to 182 ft. The average thickness is approximately 93 ft. In the bluff area, the older fluvial sediments range in thickness from 0 to 151 ft and are overlain by 22 to 82 ft of loess."

"The Holocene Series consists of alluvium and colluvial deposits with in the Loess Hills and the Mississippi Alluvial Valley. [... ] Borings near the foot of the bluff and in the tributary valleys that drain the bluff area encountered colluvial deposits up to 47ft thick.

Along the bluff the colluvium generally consists of a brown silt, clayey silt, or silty clay, which is derived from the Loess bluff."

"The bluffs adjacent to the Alluvial Valley are composed of Pleistocene loess. The average preconstruction thickness at the site is 65 feet, with extremes of 22 and 82 ft.

The upper 10 to 15 feet of loess consists of a moist clayey silt. Below this depth the loess consists of a dry, homogeneous layer of unstratified silt which generally occurs along old drainage channels or areas where impermeable terrace clays form shallow basins in which infiltrating water accumulates."

"Underlying the loess are unnamed, "pre-loess," terrace deposits comprised primarily of clayey silt, silty clay and sand. [...] Where penetrated, the thickness ranged from 8 to 151 ft and averaged 51 ft."

"Most deep site borings encountered the Miocene age Catahoula Formation. The Catahoula consists of a hard-to-very-hard, gray-to gray-green, silty-to-sandy clay, and clayey silt and sand, with some locally indurated or cemented clay, sand, and silt seams.

[...] The maximum estimated thickness of the Catahoula Formation at the site is 320 ft."

"Unconformably underlying the Catahoula Formation is the Vicksburg Group, a sequence of four formations of Oligocene age. These formations, from youngest to oldest, are the Bucatunna, the Byram, the Glendon, and the Mint Spring. [...] The Bucatunna is a 53-ft thick layer of stiff-to hard greenish-black-to-black clay with a thin, gray, fine sand seams. [...] The Byram Marl, underlying the Bucatunna, is hard-to-very-hard, green-to-gray, fine sandy, calcareous clay approximately 5 ft thick. [...]

8

Comformably underlying the Byram Marl is the Glendon Formation. It consists of a series of interbedded, light gray, fossiliferous limestones and hard-to-partly-indurated, grayish-green, fine sandy, calcareous clays. Total thickness is about 46 ft. [...]

Underlying the Glendon is the Mint Spring Marl. Forty feet of the Mint Spring Marl was penetrated at the site; however, the total thickness of the formation was not determined.

The formation consists of hard, grayish green fossiliferous, glauconitic sand and clay."

"The Catahoula Formation of Miocene age is the foundation-bearing stratum for the major plant structures. It consists primarily of hard-to-very-hard silty-to sandy clay, clayey silt, and locally indurated or cemented clay, silt and sand layers. The in-situ shear wave velocity of the Catahoula Formation is 1700 to 1800 fps and the compressional wave velocity is 6400 to 6700 fps."

The GGNS site consists of a layer of Holocene Alluvium (145 ft) consisting of clay, silt, sand and gravel. Next is a thin layer of Pleistocene Loess (82 ft) consisting of silt and Terrace Deposits (151 ft) consisting of clay, sand and gravel. This is followed by a deposit of Miocene Catahoula Clay (320 ft) consisting of silty fine sandy clay, partly indurated. Below the Catahoula Clay is deposits for Oligocene (Vicksburg Group) consisting of Bucatunna (53 ft of stiff-hard black clay/fine sand), Byram Marl (5 ft of Hard Sandy Clay), Glendon Limestone (46 ft of Interrended Fossiliferous Limestone and Hard Calcareous Clay), Mint Spring Marl (40 ft of Hard Calcareous Clay) and Forest Hill (60 ft of Silty Micaceous Clay, Sandstone, and Silts). (Entergy, 2013) 2.3.2 Development of Base Case Profiles and Nonlinear Material Properties Table 2.3.1-1 shows the recommended shear-wave velocities and unit weights versus depth and elevation for the best estimate single profile to an elevation of -103 ft (-31 m). This elevation is at a depth of 190 ft (58 m) below the SSE Control Point. In-situ shear and compressional-wave velocity measurements at the site were made in the Catahoula clay formation (Entergy, 2013). Recommended shear-wave velocities listed in Table 2.3.1-1 were taken as the mean base-case profile (P1) in the top 190 ft (58 m). Beneath this depth the profile was extended to a depth of 4,000 ft (1,219 m) using the Vs30 270 m/sec (886 ftls)profile template from the SPID (EPRI, 2013a). The depth of 4,000 ft (1,219 m) was considered adequate to reflect amplification over the lowest frequency of interest, about 0.5 Hz (EPRI, 2013a). (EPRI, 2014)

Lower (P2)- and upper (P3)- range profiles were developed with a scale factor of 1.25 reflecting uncertainty in measured velocities to a depth of 190 ft (58 m). To accommodate increased epistemic uncertainty below a depth of 190 ft (58 m) reflecting assumed shear-wave velocities, a scale factor of 1.57 was used. To alleviate the development of a low velocity zone in the softer profile (P2) below 190 ft (58 m), the discontinuity in profile P2 at 190 ft (58 m) was smoothed to a depth of about 400 ft (122 m), where the full scale factor of 1.57 was reached.

The scale factors of 1.25 and 1.57 reflect a a~ln of about 0.2 and about 0.35 respectively based on the SPID (EPRI, 2013a) 10th and 90th fractiles which implies a scale factor of 1.28 on a~ln.

Depth to Precambrian basement was taken at 4,000 ft (1,219 m) randomized +/-1 ,200 ft (366 m).

9

The three shear-wave velocity profiles are shown in Figure 2.3.2-1 and listed in Table 2.3.2-1 (EPRI, 2014)

Vs profiles for Grand Gulf Site Vs (ft/sec) o 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 O+--+--..-__...__-w----I----I----I----I----I----I----I-----I 500 ;---t-il--

1000 +---+-

-Profile 1

!:. 2000 +--+--~+__-&amar -Profile 2

.c

~

Q. ~Profile3

~ 2500 +--+--fi-l-----iH----I--+--I----I----I----I----I------i 3000 . _ - --l----11-- ----. . -...t - - - - i - ' - - - . - - - - -

3500 +----I---+---......--I-----fl--I---+--+--+---I-----I 4500 -'----'----'----'----'----'----'----'----'---~----'

Figure 2.3.2-1 Shear-wave velocity profiles for the GGNS. (EPRI, 2014)

Table 2.3.2-1 Layer thicknesses, depths, and shear-wave velocities (Vs) for 3 profiles, GGNS (EPRI, 2014)

Profile 1 Profile 2 Profile 3 thickness depth Vs thickness depth Vs thickness depth Vs (ft) (ft) (ft/s) (ft) (ft) (ftls) (ft) (ft) (ftls) 0 1600 0 1280 0 2000 10.2 10.2 1600 10.2 10.2 1280 10.2 10.2 2000 10.2 20.3 1600 10.2 20.3 1280 10.2 20.3 2000 12.5 32.8 1640 12.5 32.8 1312 12.5 32.8 2050 12.5 45.3 1640 12.5 45.3 1312 12.5 45.3 2050 4.6 49.9 1640 4.6 49.9 1312 4.6 49.9 2050 7.9 57.7 1640 7.9 57.7 1312 7.9 57.7 2050 12.5 70.2 1640 12.5 70.2 1312 12.5 70.2 2050 12.5 82.7 1720 12.5 82.7 1376 12.5 82.7 2150 12.5 95.1 1720 12.5 95.1 1376 12.5 95.1 2150 12.5 107.6 1720 12.5 107.6 1376 12.5 107.6 2150 12.5 120.1 1720 12.5 120.1 1376 12.5 120.1 2150 14.1 134.2 1715 14.1 134.2 1372 14.1 134.2 2144 14.1 148.3 1715 14.1 148.3 1372 14.1 148.3 2144 10

Table 2.3.2-1 Layer thicknesses, depths, and shear-wave velocities (Vs) for 3 profiles, GGNS (EPRI, 2014)

Profile 1 Profile 2 Profile 3 thickness depth Vs thickness depth Vs thickness depth Vs (ft) (ft) (ftls) (ft) (ft) (ftls) (ft) (ft) (ftls) 14.1 162.4 1715 14.1 162.4 1372 14.1 162.4 2144 14.1 176.5 1715 14.1 176.5 1372 14.1 176.5 2144 14.1 190.6 1715 14.1 190.6 1372 14.1 190.6 2144 17.7 208.3 1800 17.7 208.3 1312 17.7 208.3 2826 17.7 226.0 1800 17.7 226.0 1312 17.7 226.0 2826 17.7 243.8 1800 17.7 243.8 1312 17.7 243.8 2826 6.2 250.0 1800 6.2 250.0 1312 6.2 250.0 2826 44.0 294.0 1800 44.0 294.0 1312 44.0 294.0 2826 32.8 326.8 1873 32.8 326.8 1312 32.8 326.8 2941 32.8 359.6 1873 32.8 359.6 1312 32.8 359.6 2941 32.8 392.4 1873 32.8 392.4 1312 32.8 392.4 2941 40.0 432.4 2005 40.0 432.4 1283 40.0 432.4 3147 40.0 472.4 2005 40.0 472.4 1283 40.0 472.4 3147 27.6 500.0 2005 27.6 500.0 1283 27.6 500.0 3147 52.5 552.5 2005 52.5 552.5 1283 52.5 552.5 3147 40.0 592.5 2005 40.0 592.5 1283 40.0 592.5 3147 42.7 635.2 2005 42.7 635.2 1283 42.7 635.2 3147 42.7 677.8 2005 42.7 677.8 1283 42.7 677.8 3147 42.7 720.5 2005 42.7 720.5 1283 42.7 720.5 3147 65.6 786.1 2182 65.6 786.1 1396 65.6 786.1 3425 65.6 851.7 2182 65.6 851.7 1396 65.6 851.7 3425 65.6 917.3 2182 65.6 917.3 1396 65.6 917.3 3425 65.6 982.9 2182 65.6 982.9 1396 65.6 982.9 3425 65.6 1048.6 2182 65.6 1048.6 1396 65.6 1048.6 3425 65.6 1114.2 2359 65.6 1114.2 1510 65.6 1114.2 3704 65.6 1179.8 2359 65.6 1179.8 1510 65.6 1179.8 3704 65.6 1245.4 2359 65.6 1245.4 1510 65.6 1245.4 3704 65.6 1311.0 2359 65.6 1311.0 1510 65.6 1311.0 3704 65.6 1376.6 2359 65.6 1376.6 1510 65.6 1376.6 3704 131.2 1507.9 2552 131.2 1507.9 1634 131.2 1507.9 4007 131.2 1639.1 2552 131.2 1639.1 1634 131.2 1639.1 4007 131.2 1770.3 2552 131.2 1770.3 1634 131.2 1770.3 4007 131.2 1901.6 2552 131.2 1901.6 1634 131.2 1901.6 4007 131.2 2032.8 2552 131.2 2032.8 1634 131.2 2032.8 4007 131.2 2164.0 2871 131.2 2164.0 1837 131.2 2164.0 4507 131.2 2295.3 2871 131.2 2295.3 1837 131.2 2295.3 4507 131.2 2426.5 2871 131.2 2426.5 1837 131.2 2426.5 4507 131.2 2557.7 2871 131.2 2557.7 1837 131.2 2557.7 4507 131.2 2689.0 2871 131.2 2689.0 1837 131.2 2689.0 4507 11

Table 2.3.2-1 Layer thicknesses, depths, and shear-wave velocities (Vs) for 3 profiles, GGNS (EPRI, 2014)

Profile 1 Profile 2 Profile 3 thickness depth Vs thickness depth Vs thickness depth Vs (ft) (ft) (ftls) (ft) (ft) (ftls) (ft) (ft) (ftls) 164.0 2853.0 3054 164.0 2853.0 1955 164.0 2853.0 4795 164.0 3017.1 3054 164.0 3017.1 1955 164.0 3017.1 4795 164.0 3181.1 3054 164.0 3181.1 1955 164.0 3181.1 4795 164.0 3345.1 3054 164.0 3345.1 1955 164.0 3345.1 4795 164.0 3509.2 3054 164.0 3509.2 1955 164.0 3509.2 4795 490.5 3999.7 3054 490.5 3999.7 1955 490.5 3999.7 4795 3280.8 7280.5 9285 3280.8 7280.5 9285 3280.8 7280.5 9285 2.3.2.1 Shear Modulus and Damping Curves Site-specific nonlinear dynamic material properties were not available for the soils at the GGNS.

The soil material over the upper 500 ft (150 m) was assumed to have behavior that could be modeled with either EPRI cohesionless soil or Peninsular Range (PR) G/G max and hysteretic damping curves (EPRI, 2013a). Consistent with the SPID (EPRI, 2013a), the EPRI soil curves (model M1) were considered to be appropriate to represent the more nonlinear response likely to occur in the materials at this site. The PR curves (EPRI, 2013a) for soils (model M2) was assumed to represent an equally plausible alternative more linear response across loading level. (EPRI, 2014) 2.3.2.2 Kappa Base-case kappa estimates were determined using Section B-5.1.3.1 of the SPID (EPRI, 2013a) for a deep, greater than 3,000 ft (1,000 m), CEUS soil site. Kappa for a soil site with greater than 3,000 ft (1 km) was assumed to have maximum value of 0.04 s (Table 2.3.2-2).

Epistemic uncertainty in profile damping (kappa) was considered to be accommodated at design loading levels by the multiple (2) sets of G/G max and hysteretic damping curves. (EPRI, 2014) 12

Table 2.3.2-2 Kappa Values and Weights Used for Site Response Anal/ses. (EPRI, 2014)

Velocitv Profile Kappa(s)

P1 0.040 P2 0.040 P3 0.040 Velocity Profile Weiahts P1 0.4 P2 0.3 P3 0.3 G/G max and Hvsteretic Damoina Curves M1 0.5 M2 0.5 2.3.3 Randomization of Base Case Profiles To account for the aleatory variability in dynamic material properties that is expected to occur across a site at the scale of a typical nuclear facility, variability in the assumed shear-wave velocity profiles has been incorporated in the site response calculations. For GGNS, random shear wave velocity profiles were developed from the base case profiles shown in Figure 2.3.2-

1. Consistent with the discussion in Appendix 8 of the SPID (EPRI, 2013a), the velocity randomization procedure made use of random field models which describe the statistical correlation between layering and shear wave velocity. The default randomization parameters developed in (Toro, 1997) for United States Geological Survey "A" site conditions were used for this site. Thirty random velocity profiles were generated for each base case profile. These random velocity profiles were generated using a natural log standard deviation of 0.25 over the upper 50 ft and 0.15 below that depth. As specified in the SPID (EPRI, 2013a), correlation of shear wave velocity between layers was modeled using the footprint correlation model. In the correlation model, a limit of +/- 2 standard deviations about the median value in each layer was assumed for the limits on random velocity fluctuations. (EPRI, 2014) 2.3.4 Input Spectra Consistent with the guidance in Appendix 8 of the SPID (EPRI, 2013a), input Fourier amplitude spectra were defined for a single representative earthquake magnitude (M 6.5) using two different assumptions regarding the shape of the seismic source spectrum (single-corner and double-corner). A range of 11 different input amplitudes (median Peak Ground Accelerations (PGAs) ranging from 0.01 to 1.5g) were used in the site response analyses. The characteristics of the seismic source and upper crustal attenuation properties assumed for the analysis of GGNS were the same as those identified in Tables 8-4,8-5,8-6 and 8-7 of the SPID (EPRI, 2013a) as appropriate for typical CEUS sites. (EPRI, 2014) 13

2.3.5 Methodology To perform the site response analyses for the GGNS, a random vibration theory approach was employed. This process utilizes a simple, efficient approach for computing site-specific amplification functions and is consistent with existing NRC guidance and the SPID (EPRI, 2013a). The guidance contained in Appendix B of the SPID (EPRI, 2013a) on incorporating epistemic uncertainty in shear-wave velocities, kappa, non-linear dynamic properties and source spectra for plants with limited at-site information was followed for the GGNS. (EPRI, 2014) 2.3.6 Amplification Functions The results of the site response analysis consist of amplification factors (5% damped pseudo absolute response spectra) which describe the amplification (or de-amplification) of hard reference rock motion as a function of frequency and input reference rock amplitude. The amplification factors are represented in terms of a median amplification value and an associated standard deviation (sigma) for each oscillator frequency and input rock amplitude. Consistent with the SPID (EPRI, 2013a) a minimum median amplification value of 0.5 was employed in the present analysis. Figure 2.3.6-1 illustrates the median and +/-1 standard deviation in the predicted amplification factors developed for the eleven loading levels parameterized by the median reference (hard rock) peak acceleration (0.01 g to 1.50g) for profile P1 and EPRI soil G/G max and hysteretic damping curves (EPRI, 2013a). The variability in the amplification factors results from variability in shear-wave velocity, depth to hard rock, and modulus reduction and hysteretic damping curves. To illustrate the effects of more linear response at the GGNS deep soil site, Figure 2.3.6-2 shows the corresponding amplification factors developed with PR curves for soil (model M2). Between the more nonlinear and more linear analyses, Figures 2.3.6-1 and Figure 2.3.6-2 respectively show little difference across structural frequency as well as loading level. Tabular data for Figure 2.3.6-1 and Figure 2.3.6-2 is provided For Information Only in Appendix A. (EPRI, 2014) 14

c ....

CI ~ g cO U

Cl CJ 4-0

~

CL E

a:

"7 INPUT MOTION O.OlG I INPUT MeTICl-l O.OSG 9 a....

c .....

.~ ~ ~

-+-'

cO U

~CJ 0

.,.., 8 =:l a...

E a: ....

I INPUT MOTION O. lOG I INPUT MOTICl-l O.20G

~ 9 c ....

a ~ 9

+'

to U

0

...... Cl 0

~

a...

E a: ....

I INPUT MOTION O.30G INPUT l'IOTICti O.40G 9 9 10 -1 to 0 1() 1 10 2 10 -1 10 0 111 1 10 2 Frequenc~ (Hz) Frequenc~ (Hz)

AMPLIFICATION, GRAND GULF, M1P1Kl M6.5, 1 CORNER; PRGE 1 OF 2 Figure 2.3.6-1 Example suite of amplification factors (5% damping pseudo absolute acceleration spectra) developed for the mean base-case profile (P1), EPRI soil modulus reduction and hysteretic damping curves (model M1), and base-case kappa at eleven loading levels of hard rock median peak acceleration values from O.Otg to 1.50g. M 6.5 and single-corner source model. (EPRI, 2013a) (EPRI, 2014) 15

c ....

o 9 CJ

-0

+J

((j u

~o 0

..... ~ I----------=""O":~----___l 0 a...

E a: ....

I INPUT MOTION a.SOG I INPUT MOTION O.75G 9 ~..J-...I.....I....I...I.lu.u.._.I..-I....L..I....I..I.l..l.l.....--I..--L.....L..LIL.ll.IJ ~ L..-....L......I.....I.....L.LII.U.L_.L..-l....L..I...LL1..LL..---l...--L....L.L..I..L1.JJ c ....

0';:

IIJ U

0

..... 0 a....

E a:

INPUT t1OTI~ 1.2SG c:

o ::!

+'

/(1 (J

~o 0

a...

E a: ....

I INPUT MOTION 1,SOG 10 -1 to 0 10 1 10 2 Fr E' qU en c ~ (Hz)

AMPLIFICATION, GRAND GULF, M1P1Kl M6.S} 1 CORNER: PRGE Z OF Z Figure 2.3.6-1 (cant.)

16

c-o g g

+J I(j u

':0 Cl

.,.., 0

~

a...

E a: .....

I INPUT MOllON a.GiG I INPUT MOTION O.05G Sl ~

c

+'

o~ 0 10 (J

':0

..... 0 C)

S!

a...

E IT i INPUT MOTION a.tOG I INPuT MOTION O.20G e 9 c::

.....oS: ~

+'

to U

~o Cl

..... 0

~

Q...

E a: ..... .....I I

INPUT MOTION O.30G INPUT MOTION a.40G 9 9 10 -1 to a 10 1 10 2 10 -1 10 0 10 1 10 2 FreguEnc~ (Hz) FrEguenc~ (Hz)

AMPLIFICATION) GRAND GULF, M2P1Kl M6.5) 1 CORNER: PRGE 1 OF Z Figure 2.3.6-2 Example suite of amplification factors (5% damping pseudo absolute acceleration spectra) developed for the mean base-case profile (P1), Peninsular Range curves for soil (model M2), and base-case kappa at eleven loading levels of hard rock median peak acceleration values from 0.01 g to 1.50g. M 6.5 and single-corner source model. (EPRI, 2013a) (EPRI, 2014) 17

c ....

og 9

~

([j u

0 0 4-

.,..., CJ

~

CL E

10 U

~o

...... 0 a....

E cc

-I 9

INPUT ~OTION 1.S0G 10 -1 Ul 0 10 1 10 2 FreguEnc~ (Hz)

AMPLIFICATION} GRAND GULF, M2P1K1 M6.S} 1 CORNER; PRGE 2 OF Z Figure 2.3.6-2 (cant.)

18

2.3.7 Control Point Seismic Hazard Curves The procedure to develop probabilistic site-specific control point hazard curves used in the present analysis follows the methodology described in Section 8-6.0 of the SPID (EPRI, 2013a).

This procedure (referred to as Method 3) computes a site-specific control point hazard curve for a broad range of spectral accelerations given the site-specific bedrock hazard curve and site-specific estimates of soil or soft-rock response and associated uncertainties. This process is repeated for each of the seven spectral frequencies for which ground motion equations are available. The dynamic response of the materials below the control point was represented by the frequency and amplitude-dependent amplification functions (median values and standard deviations) developed and described in the previous section. The resulting control point mean hazard curves for GGNS are shown in Figure 2.3.7-1 for the seven spectral frequencies for which ground motion equations are defined. Tabulated values of mean and fractile seismic hazard curves and site response amplification functions are provided in Appendix A. (EPRI, 2014)

Total Mean Soil Hazard by Spectral Frequency at Grand Gulf OJ 1E-3 u

s::::

OJ -25Hz "C

OJ OJ u

-10Hz

)( 1E-4

....0 OJ ,~,,--' 5 Hz

> -=PGA u

s::::

OJ

, -2.5 Hz C'"

1E-5 ---~

-1Hz

....OJ

~

ra -0.5 Hz s::::

s:::: 1E-6

<t 1E-7 +-----'---'-----'--.....-..--i.....<'-'-+---------"------'---'----'--'I''----'~~--'----'---'--'--'-"_'_i 0.01 0.1 1 10 Spectral acceleration (g)

Figure 2.3.7-1 Control point mean hazard curves for spectral frequencies of 0.5, 1.0,2.5,5.0, 10,25 and PGA (100) Hz at GGNS. (EPRI, 2014) 19

2.4 Control Point Response Spectrum The control point hazard curves described above have been used to develop Uniform Hazard Response Spectra (UHRS) and the GMRS. The UHRS were obtained through linear interpolation in log-log space to estimate the spectral acceleration at each spectral frequency for the 10-4 and 10-5 per year hazard levels. Table 2.4-1 shows the UHRS and GMRS accelerations for a range of frequencies. (EPRI, 2014)

Table 2.4-1 UHRS and GMRS for GGNS. (EPRI, 2014)

Frequency 10-4 UHRS 10-5 UHRS GMRS (Hz) (0) (0) (g) 100 6.96E-02 1.82E-01 9.03E-02 90 6.98E-02 1.86E-01 9.17E-02 80 7.01E-02 1.90E-01 9.34E-02 70 7.05E-02 1.95E-01 9.55E-02 60 7.09E-02 2.01 E-01 9.79E-02 50 7.16E-02 2.09E-01 1.01 E-01 40 7.29E-02 2.20E-01 1.06E-01 35 7.41 E-02 2.29E-01 1.10E-01 30 7.62E-02 2.41 E-01 1.15E-01 25 8.01E-02 2.62E-01 1.24E-01 20 8.59E-02 2.66E-01 1.27E-01 15 1.00E-01 2.89E-01 1.40E-01 12.5 1.12E-01 3.09E-01 1.51 E-01 10 1.26E-01 3.25E-01 1.61 E-01 9 1.35E-01 3.42E-01 1.70E-01 8 1.47E-01 3.66E-01 1.83E-01 7 1.55E-01 3.85E-01 1.92E-01 6 1.59E-01 3.92E-01 1.96E-01 5 1.65E-01 3.94E-01 1.98E-01 4 1.62E-01 3.75E-01 1.90E-01 3.5 1.62E-01 3.63E-01 1.85E-01 3 1.57E-01 3.44E-01 1.76E-01 2.5 1.45E-01 3.10E-01 1.60E-01 2 1.50E-01 3.19E-01 1.65E-01 1.5 1.46E-01 3.03E-01 1.57E-01 1.25 1.43E-01 2.94E-01 1.53E-01 1 1.30E-01 2.65E-01 1.38E-01 0.9 1.34E-01 2.73E-01 1.42E-01 0.8 1.19E-01 2.53E-01 1.31 E-01 0.7 1.12E-01 2.37E-01 1.23E-01 0.6 1.13E-01 2.40E-01 1.24E-01 0.5 9.40E-02 2.05E-01 1.05E-01 20

Table 2.4-1 UHRS and GMRS for GGNS. (EPRI, 2014)

Frequency 10-4 UHRS 10-5 UHRS GMRS (Hz) (g) (g) (g) 0.4 7.52E-02 1.64E-01 8.41E-02 0.35 6.58E-02 1.43E-01 7.36E-02 0.3 5.64E-02 1.23E-01 6.30E-02 0.25 4.70E-02 1.02E-01 5.25E-02 0.2 3.76E-02 8.18E-02 4.20E-02 0.15 2.82E-02 6.14E-02 3.15E-02 0.125 2.35E-02 5.12E-02 2.63E-02 0.1 1.88E-02 4.09E-02 2.10E-02 The 10-4 and 10-5 UHRS are used to compute the GMRS at the control point and are shown in Figure 2.4-1.

Mean Soil UHRS and GMRS at Grand Gulf 0.4 QO -lE-S UHRS c"

0

',p 0.3

"'cu

~

-GMRS Qi u

u

.......... lE-4 UHRS

"'u

...., 0.2

~

v1J)=~~'~'~ ~~~-.,_

cu Q,

V) 0.1

~ ' ~......,...~r.-r. ..  !

r-.,j""fl

o. I I III

-r----'----'---'---'--"'--'-'--'-t------'--'----'--"--'--'--'-'-j---"----'---'-----'-'--'---'--'-j 0.1 1 10 100 Spectral frequency, Hz Figure 2.4-1 UHRS for 10-4 and 10-5 and GMRS at control point for GGNS (5% damped response spectra). (EPRI, 2014) 3.0 Plant Design Basis and Beyond Design Basis Evaluation Ground Motion The design basis for Grand Gulf is identified in the Updated Final Safety Analysis Report (FSAR) (Entergy, 2013) and other pertinent documents.

21

3. 1 SSE Description of Spectral Shape The SSE is based on the seismicity of both the Gulf Coast Basin tectonic province arid the zone of tectonism in the Mississippi Embayment tectonic province which is referred to as the New Madrid seismic zone. The maximum vibratory ground motion at GGNS is associated with the Gulf Coast Basin maximum potential earthquake for frequencies greater than about 1 to 2 cycles per second. The peak horizontal acceleration at the site due to this event does not exceed 0.1 g. However,Jor additional conservatism an SSE of 0.15g was selected. The maximum vibratory ground motion at the site for low frequencies is associated with the New Madrid seismic zone maximum potential earthquake. (Entergy,2013)

The SSE is defined in terms of a PGA and a design respons,e spectrum. Table 3.1-1 shows the Spectral Acceleration (SA) values as a function of frequency for the 5% damped horizontal SSE.

(Entergy, 2013)

Table 3.1-1 SSE for GGNS. (Entergy, 2013)

Frequency SA (Hz) (g) 100 0.15 33 0.15 25 0.15 22 0.15 10 0.30 6.7 0.40 5.0 0.40 2.5 0.40 2.0 0.40 1.0 0.20 0.50 0.10 0.26 0.036 0.10 0.009 The original SSE spectrum tabulation was augmented with additional spectral points to better define the spectrum in the frequency range of interest.

3.2 Control Point Elevation Section 2.5, Page 2.5-2 of the GGNS FSAR (Entergy, 2013) states that "the safe shutdown earthquake (SSE) is conservatively selected at 0.15g at foundation grade on the Catahoula formation." As such, the SSE control point elevation is defined at elevation 87 ft, which is the top of the Catahoula Formation (Entergy, 2013). The bottom of the foundation of the highest safety-related structure is 3'-6" below, at Elev. 83'-6".

22

3.3/PEEE Description and Capacity Response Spectrum The Individual Plant Examination of External Events (IPEEE) was performed as a reduced scope. Because GGNS screens-out from performing any further evaluations, the IPEEE was not reviewed.

4.0 Screening Evaluation In accordance with SPID Section 3 (EPRI, 2013a), a screening evaluation was performed as described below.

4.1 Risk Evaluation Screening (1 to 10 Hz)

In the 1 to 10Hz part of the response spectrum, the SSE exceeds the GMRS. Therefore, a risk evaluation will not be performed. Additionally, based on the SSE and GMRS comparison, GGNS will screen-out of -the expedited seismic evaluation described in EPRI 3002000704 (EPRI, 2013b) as proposed in a letter to the NRC (ML13101A379) dated April 9, 2013 (NEI, 2013) and agreed to by the NRC (ML13106A331) in a letter dated May 7, 2013 (U.S. NRC, 2013).

4.2 High Frequency Screening (> 10 Hz)

Above 10Hz, the SSE exceeds the GMRS. Therefore, the High Frequency Confirmation will not be performed.

4.3 Spent Fuel Pool Evaluation Screening (1 to 10 Hz)

In the 1 to 10 Hz part of the response spectrum, the SSE exceeqs the GMRS. Therefore, a Spent Fuel Pool evaluation will not be performed.

5.0 Interim Actions Based on the screening evaluation, the expedited seismic evaluation described in EPRI 3002000704 will not be performed.

Consistent with NRC letter (ML14030A046) dated February 20, 2014, (U.S. NRC, 2014) the seismic hazard reevaluations presented herein are distinct from the current design and licensing bases of GGNS. Therefore, the results do not call into question the operability or functionality of Structures, Systems, and Components and are not reportable pursuant t01 0 CFR 50.72, "Immediate notification requirements for operating nuclear power reactors," and10 CFR 50.73, "Licensee event report system".

The NRC letter also requests that licensees provide an interim evaluation or actions to demonstrate that the plant can cope with the reevaluated hazard while the expedited approach 23

and risk evaluations are conducted. In response to that request, NElletter dated March 12, 2014 (NEI, 2014), provides seismic core damage risk estimates using the updated seismic hazards for the operating nuclear plants in the Central and Eastern United States. These risk estimates continue to support the following conclusions of the NRC GI-199 Safety/Risk Assessment (U.S. NRC, 2010):

Overall seismic core damage risk estimates are consistent with the Commission's Safety Goal Policy Statement because they are within the subsidiary objective of 10*4/year for core damage frequency. The GI-199 Safety/Risk Assessment, based in part on information from the U.S. Nuclear Regulatory Commission's (NRC's) Individual Plant Examination of External Events (IPEEE) program, indicates that no concern exists regarding adequate protection and that the current seismic design of operating reactors provides a safety margin to withstand potential earthquakes exceeding the original design basis.

GGNS is included in the March 12, 2014 risk estimates. Using the methodology described in the NEI letter, all plants were shown to be below 10-4/year; thus, the above conclusions apply (NEI, 2014).

In accordance with the Near-Term Task Force Recommendation 2.3, GGNS performed seismic walkdowns using the guidance in EPRI Report 1025286 (EPRI, 2012). The seismic walkdowns were completed and captured in Fukushima Seismic Walkdown Report GNRO-2012/00141 (Entergy, 2012). The goal of the walkdowns was to verify current plant configuration with the existing licensing basis, to verify the current maintenance plans, and to identify any vulnerabilities. The walkdown also verified that any vulnerabilities identified in the IPEEE (Entergy, 1995) were adequately addressed. The results of the walkdown, including any identified corrective actions, confirm that GGNS can adequately respond to a seismic event.

6.0 Conclusions In accordance with the 50.54(f) request for information (U.S. NRC, 2012), a seismic hazard and screening evaluation was performed for GGNS. A GMRS was developed solely for the purpose of screening for additional evaluations in accordance with the SPID (EPRI, 2013a). Based on the results of the screening evaluation, no further evaluations will be performed.

24

7.0 References 10 CFR Part 50. Title 10, Code of Federal Regulations, Part 50, "Domestic Licensing of Production and Utilization Facilities," U.S. Nuclear Regulatory Commission, Washington DC.

. 10 CFR Part 50.72. Title 10, Code of Federal Regulations, Part 50.72, "Immediate Notification Requirements for Operating Nuclear Power: Reactors," U.S. Nuclear Regulatory Commission, Washington DC.

10 CFR Part 50.73. Title 10, Code of Federal Regulations, Part 50.73, "Licensee Event Report System," U.S. Nuclear Regulatory Commission, Washington DC.

10 CFR Part 100. Title 10, Code of Federal Regulations, Part 100, "Reactor Site Criteria," U.S.

Nuclear Regulatory Commission, Washington, DC.

CEUS-SSC (2012). "Central and Eastern United States Seismic Source Characterization for Nuclear Facilities," U.S. Nuclear Regulatory Commission Report, NUREG-2115; EPRI Report 1021097, 6 Volumes; DOE Report# DOE/NE-0140.

Entergy (1995). "Grand Gulf Nuclear Station Engineering Report for IPEEE Reduced Scope Seismic Margin Assessment (SMA)," GGNS-94-0053, Revision 0, dated January 5, 1995.

Entergy (2012). "Seismic Walkdown Report - Entergy's Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding the Seismic Aspects of Recommendation 2.3 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident; Grand Gulf Nuclear Station, Unit *No. 1; Docket No. 50-416; License No. NPF-29," GNRO-2012/00141 , dated November 27, 2012.

Entergy (2013). "Grand Gulf Nuclear Station Updated Final Safety Analysis Report," Docket No.

50-416,2013.

EPRI (2012). "Seismic Walkdown Guidance for Resolution of Fukushima Near-Term Task Force Recommendation 2.3: Seismic," EPRI 1025286, Draft 7 Report, May 2012.

EPRI (2013a). "Seismic Evaluation Guidance Screening, Prioritization and Implementation Details (SPID) for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic," EPRI 1025287, February 2013.

EPRI (2013b). "Seismic Evaluation Guidance: Augmented Approach for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1 - Seismic," EPRI 3002000704, Final Report, May 2013.

EPRI (2013c). "EPRI (2004, 2006) Ground-Motion Model (GMM) Review Project," EPRI 3002000717, 2 volumes, June 2013.

EPRI (2014). "Grand Gulf Seismic Hazard and Screening Report," Electric Power Research Institute, Palo Alto, CA, dated February 14, 2014.

NEI (2013). NEI Letter to NRC, "Proposed Path Forward for NTTF Recommendation 2.1 :

Seismic Reevaluations," April 9, 2013.

NEI (2014). NEI Letter to NRC, "Seismic Risk Evaluations for Plants in the Central and Eastern United States," March 12, 2014.

Toro (1997). Appendix of: Silva, W.J., Abrahamson, N., Toro, G., and Costantino, C. (1997).

"Description and Validation of the Stochastic Ground Motion Model," Report Submitted 25

to Brookhaven National Laboratory, Associated Universities, Inc., Upton, New York 11973, Contract No. 770573.

U.S. NRC (2007). "A Performance-Based Approach to Define the Site-Specific Earthquake Ground Motion," U.S. Nuclear Regulatory Commission Reg. Guide 1.208.

U.S. NRC (2010). "Implications of Updated Probabilistic Seismic Hazard Estimates in Central and Eastern United States on Existing Plants," GI-199, September 2, 2010.

U.S. NRC (2012). NRC (E Leeds and M Johnson) Letter to All Power Reactor Licensees et aI.,

"Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f)

Regarding Recommendations 2.1,2.3 and 9.3 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident," March 12, 2012.

U.S. NRC (2013). NRC Letter, Eric J. Leeds to Joseph E. Pollock, NEI "Electric Power Research Institute Final Draft Report XXXXXX, Seismic Evaluation Guidance:

Augmented Approach for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic, As an Acceptable Alternative to the March 12, 2012, Information Request for Seismic Reevaluation," dated May 7, 2013.

U.S. NRC (2014). NRC Letter, Eric J. Leeds to All Power Reactor Licensees, "Supplemental Information Related to Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Seismic Hazard Reevaluations for Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-Ichi Accident," dated February 20, 2014.

26

Appendix A Tabulated Data 27

Table A-1 a. Mean and Fractile Seismic Hazard Curves for PGA at GGNS.

(EPRI, 2014)

AMPS(Q) MEAN 0.05 0.16 0.50 0.84 0.95 0.0005 4.69E-02 1.87E-02 3.42E-02 4.63E-02 6.17E-02 7.13E-02 0.001 2.90E-02 1.07E-02 1.95E-02 2.72E-02 4.01 E-02 4.98E-02 0.005 6.92E-03 2.53E-03 3.95E-03 6.26E-03 9.51 E-03 1.46E-02 0.01 3.70E-03 9.93E-04 1.67E-03 3.19E-03 5.66E-03 8.23E-03 0.015 2.37E-03 4.77E-04 8.35E-04 1.87E-03 3.95E-03 6.09E-03 0.03 7.53E-04 9.11 E-05 1.64E-04 4.13E-04 1.29E-03 2.64E-03 0.05 2.31 E-04 2.10E-05 4.07E-05 1.05E-04 3.14E-04 8.72E-04 0.075 8.28E-05 6.93E-06 1.46E-05 3.95E-05 1.08E-04 2.96E-04 0.1 4.02E-05 3.47E-06 7.77E-06 2.13E-05 5.66E-05 1.32E-04 0.15 1.55E-05 1.42E-06 3.37E-06 9.51 E-06 2.42E-05 4.83E-05 0.3 3.29E-06 2.72E-07 6.93E-07 2.13E-06 5.50E-06 1.01 E-05 0.5 9.35E-07 6.00E-08 1.67E-07 5.75E-07 1.60E-06 3.01 E-06 0.75 3.07E-07 1.46E-08 4.31 E-08 1.74E-07 5.20E-07 1.07E-06

1. 1.30E-07 4.50E-09 1.42E-08 6.73E-08 2.19E-07 4.77E-07 1.5 3.54E-08 7.23E-10 2.53E-09 1.49E-08 5.66E-08 1.51 E-07
3. 2.77E-09 1.29E-10 1.98E-10 8.00E-10 3.90E-09 1.49E-08
5. 3.07E-10 1.11 E-1 0 1.21 E-10 1.82E-10 5.05E-10 1.90E-09 7.5 4.34E-11 1.11 E-10 1.21 E-10 1.72E-10 1.95E-10 4.01 E-10
10. 9.80E-12 1.11 E-1 0 1.11 E-1 0 1.72E-10 1.72E-10 2.04E-10 Table A-1 b. Mean and Fractile Seismic Hazard Curves for 25 Hz at GGNS.

(EPRI, 2014)

AMPS(Q) MEAN 0.05 0.16 0.50 0.84 0.95 0.0005 5.06E-02 2.46E-02 3.95E-02 5.05E-02 6.36E-02 7.34E-02 0.001 3.28E-02 1.44E-02 2.35E-02 3.14E-02 4.19E-02 5.50E-02 0.005 8.78E-03 3.57E-03 5.20E-03 7.89E-03 1.16E-02 1.90E-02 0.01 4.86E-03 1.57E-03 2.46E-03 4.31 E-03 7.03E-03 1.05E-02 0.015 3.20E-03 8.23E-04 1.34E-03 2.64E-03 5.05E-03 7.55E-03 0.03 1.06E-03 1.67E-04 2.80E-04 6.54E-04 1.84E-03 3.42E-03 0.05 3.22E-04 3.68E-05 6.64E-05 1.60E-04 4.63E-04 1.21 E-03 0.075 1.17E-04 1.20E-05 2.39E-05 6.00E-05 1.51 E-04 4.13E-04 0.1 5.97E-05 6.36E-06 1.32E-05 3.47E-05 8.12E-05 1.92E-04 0.15 2.62E-05 3.05E-06 6.73E-06 1.82E-05 4.07E-05 7.34E-05 0.3 7.90E-06 9.37E-07 2.32E-06 6.26E-06 1.31 E-05 2.01 E-05 0.5 3.21 E-06 3.57E-07 9.51 E-07 2.57E-06 5.42E-06 8.23E-06 0.75 1.45E-06 1.46E-07 3.95E-07 1.11 E-06 2.49E-06 3.84E-06

1. 7.80E-07 7.34E-08 1.98E-07 5.83E-07 1.32E-06 2.16E-06 1.5 2.96E-07 2.42E-08 6.64E-08 2.10E-07 5.05E-07 8.98E-07
3. 4.23E-08 2.25E-09 6.45E-09 2.49E-08 7.23E-08 1.55E-07
5. 7.73E-09 3.42E-10 8.85E-10 3.73E-09 1.32E-08 3.14E-08 7.5 1.68E-09 1.49E-10 2.39E-10 7.55E-10 2.88E-09 7.55E-09
10. 5.19E-10 1.21 E-10 1.62E-10 2.92E-10 9.93E-10 2.42E-09 28

Table A-1c. Mean and Fractile Seismic Hazard Curves for 10 Hz at GGNS.

(EPRI, 2014)

AMPS(g) MEAN 0.05 0.16 0.50 0.84 0.95 0.0005 5.88E-02 3.57E-02 4.77E-02 5.83E-02 7.13E-02 8.00E-02 0.001 4.01 E-02 2.10E-02 3.01 E-02 3.95E-02 5.05E-02 5.91 E-02 0.005 1.04E-02 4.90E-03 6.73E-03 9.79E-03 1.36E-02 1.90E-02 0.01 5.57E-03 2.25E-03 3.23E-03 5.12E-03 7.89E-03 1.04E-02 0.015 3.81 E-03 1.29E-03 1.95E-03 3.42E-03 5.66E-03 7.66E-03 0.03 1.70E-03 3.90E-04 6.17E-04 1.29E-03 2.84E-03 4.43E-03 0.05 7.53E-04 1.25E-04 2.07E-04 4.56E-04 1.29E-03 2.39E-03 0.075 3.37E-04 4.56E-05 8.00E-05 1.82E-04 5.27E-04 1.15E-03 0.1 1.76E-04 2.16E-05 3.95E-05 9.51 E-05 2.53E-04 5.91E-04 0.15 6.61 E-05 7.45E-06 1.51 E-05 3.84E-05 9.24E-05 2.07E-04 0.3 1.21 E-05 1.31 E-06 3.01E-06 8.23E-06 1.92E-05 3.42E-05 0.5 3.58E-06 3.42E-07 8.47E-07 2.53E-06 6.17E-06 1.02E-05 0.75 1.30E-06 1.07E-07 2.80E-07 8.85E-07 2.25E-06 3.90E-06

1. 6.01 E-07 4.25E-08 1.18E-07 3.95E-07 1.05E-06 1.87E-06 1.5 1.84E-07 1.01 E-08 2.96E-08 1.13E-07 3.33E-07 6.09E-07
3. 1.86E-08 5.50E-10 1.77E-09 8.98E-09 3.23E-08 7.34E-08
5. 2.85E-09 1.62E-10 2.57E-10 1.11 E-09 4.70E-09 1.31 E-08 7.5 5.71 E-10 1.20E-10 1.53E-10 2.64E-10 1.02E-09 2.88E-09
10. 1.69E-10 1.11 E-1 0 1.21 E-10 1.72E-10 3.79E-10 1.01 E-09 Table A-1d. Mean and Fractile Seismic Hazard Curves for 5.0 Hz at GGNS.

(EPRI, 2014)

AMPS{g) MEAN 0.05 0.16 0.50 0.84 0.95 0.0005 7.06E-02 4.77E-02 5.75E-02 7.03E-02 8.35E-02 9.24E-02 0.001 5.35E-02 2.96E-02 4.01 E-02 5.35E-02 6.73E-02 7.66E-02 0.005 1.52E-02 6.83E-03 9.93E-03 1.46E-02 2.07E-02 2.49E-02 0.01 7.54E-03 3.33E-03 4.70E-03 7.23E-03 1.04E-02 1.27E-02 0.015 5.03E-03 1.98E-03 2.88E-03 4.77E-03 7.13E-03 8.98E-03 0.03 2.40E-03 6.54E-04 1.04E-03 2.07E-03 3.79E-03 5.35E-03 0.05 1.19E-03 2.32E-04 3.84E-04 8.47E-04 2.01 E-03 3.23E-03 0.075 5.85E-04 8.98E-05 1.53E-04 3.52E-04 9.51 E-04 1.90E-03 0.1 3.26E-04 4.37E-05 7.66E-05 1.79E-04 4.98E-04 1.15E-03 0.15 1.28E-04 1.49E-05 2.76E-05 6.54E-05 1.74E-04 4.56E-04 0.3 2.08E-05 2.29E-06 4.77E-06 1.23E-05 2.92E-05 6.45E-05 0.5 5.25E-06 5.42E-07 1.27E-06 3.57E-06 8.47E-06 1.51 E-05 0.75 1.74E-06 1.49E-07 3.73E-07 1.16E-06 3.01 E-06 5.27E-06

1. 7.76E-07 4.98E-08 1.29E-07 4.70E-07 1.40E-06 2.49E-06 1.5 2.34E-07 7.03E-09 2.13E-08 1.16E-07 4.37E-07 8.47E-07
3. 2.47E-08 2.01E-10 5.66E-10 7.34E-09 4.43E-08 1.07E-07
5. 3.96E-09 1.21 E-10 1.72E-10 7.55E-10 6.17E-09 1.84E-08 7.5 8.28E-10 1.11 E-1 0 1.23E-10 2.04E-10 1.18E-09 4.01 E-09
10. 2.57E-10 1.11E-10 1.21 E-10 1.72E-10 4.01E-10 1.34E-09 29

Table A-1e. Mean and Fractile Seismic Hazard Curves for 2.5 Hz at GGNS.

(EPRI, 2014)

AMPS(Q) MEAN 0.05 0.16 0.50 0.84 0.95 0.0005 7.03E-02 4.83E-02 5.66E-02 7.03E-02 8.35E-02 9.37E-02 0.001 5.30E-02 3.09E-02 3.90E-02 5.20E-02 6.83E-02 7.66E-02 0.005 1.48E-02 6.93E-03 9.51 E-03 1.40E-02 2.01 E-02 2.46E-02 0.01 7.09E-03 3.09E-03 4.31 E-03 6.73E-03 9.93E-03 1.21 E-02 0.015 4.64E-03 1.77E-03 2.57E-03 4.37E-03 6.73E-03 8.47E-03 0.03 2.19E-03 5.35E-04 8.72E-04 1.87E-03 3.57E-03 5.05E-03 0.05 1.07E-03 1.74E-04 3.05E-04 7.55E-04 1.84E-03 2.96E-03 0.075 5.04E-04 6.17E-05 1.11 E-04 2.88E-04 8.60E-04 1.69E-03 0.1 2.63E-04 2.80E-05 5.05E-05 1.34E-04 4.31 E-04 9.79E-04 0.15 9.08E-05 8.35E-06 1.55E-05 4.19E-05 1.34E-04 3.57E-04 0.3 1.11 E-05 9.37E-07 2.01 E-06 5.42E-06 1.64E-05 3.79E-05 0.5 2.30E-06 1.79E-07 4.31 E-07 1.32E-06 3.68E-06 7.03E-06 0.75 7.11E-07 4.56E-08 1.20E-07 4.19E-07 1.20E-06 2.35E-06

1. 3.15E-07 1.55E-08 4.37E-08 1.72E-07 5.50E-07 1.11 E-06 1.5 9.79E-08 2.84E-09 8.85E-09 4.37E-08 1.72E-07 3.79E-07
3. 1.13E-08 1.90E-10 4.01 E-10 2.80'E-09 1.82E-08 5.12E-08
5. 1.94E-09 '1.21 E-10 1.64E-10 3.63E-10 2.64E-09 9.24E-09 7.5 4.21E-10 1.11 E-1 0 1.21 E-10 1.72E-10 5.66E-10 2.04E-09
10. 1.32E-10 1.11 E-1 0 1.21 E-10 1.72E-10 2.46E-10 7.23E-10 Table A-H. Mean and Fractile Seismic Hazard Curves for 1.0 Hz at GGNS.

(EPRI, 2014)

AMPS(g) MEAN 0.05 0.16 0.50 0.84 0.95 0.0005 5.60E-02 2.88E-02 4.01 E-02 5.66E-02 7.13E-02 8.12E-02 0.001 3.83E-02 1.64E-02 2.53E-02 3.79E-02 5.12E-02 6.00E-02 0.005 1.05E-02 4.13E-03 6.26E-03 9.93E-03 1.46E-02 1.84E-02 0.01 5.47E-03 1.87E-03 2.92E-03 5.12E-03 8.12E-03 1.02E-02 0.015 3.72E-03 1.01 E-03 1.72E-03 3.42E-03 5.75E-03 7.55E-03 0.03 1.80E~03 2.60E-04 5.27E-04 1.46E-03 3.14E-03 4.56E-03 0.05 8.75E-04 7.55E-05 1.67E-04 5.83E-04 1.60E-03 2.64E-03 0.075 4.06E-04 2.42E-05 5.66E-05 2.22E-04 7.45E-04 1.38E-03 0.1 2.08E-04 9.93E-06 2.39E-05 9.79E-05 3.68E-04 7.66E-04 0.15 6.79E-05 2.72E-06 6.54E-06 2.68E-05 1.11 E-04 2.72E-04 0.3 6.56E-06 2.46E-07 5.91 E-07 2.35E-06 9.11 E-06 2.68E-05 0.5 9.95E-07 3.57E-08 9.37E-08 3.79E-07 1.51 E-06 3.90E-06 0.75 2.50E-07 7.03E-09 2.10E-08 9.11 E-08 4.07E-07 9.93E-07

1. 1.05E-07 2.16E-09 6.73E-09 3.52E-08 1.67E-07 4.43E-07 1.5 3.42E-08 4.50E-10 1.36E-09 8.72E-09 5.12E-08 1.57E-07
3. 4.90E-09 1.31E-10 1.84E-10 7.34E-10 5.91 E-09 2.32E-08
5. 1.01 E-09 1.11 E-1 0 1.25E-10 2.01 E-10 1.07E-09 4.70E-09 7.5 2.54E-10 1.11 E-10 1.21 E-10 1.72E-10 3.09E-10 1.21 E-09
10. 8.84E-11 1.11 E-1 0 1.21 E-10 1.72E-10 1.92E-10 4.77E-10 30

Table A-1g. Mean and Fractile Seismic Hazard Curves for 0.5 Hz at GGNS.

(EPRI, 2014)

AMPS(a) MEAN 0.05 0.16 0.50 0.84 0.95 0.0005 2.99E-02 1.49E-02 2.16E-02 2.92E-02 3.84E-02 4.56E-02 0.001 1.83E-02 8.72E-03 1.25E-02 1.77E-02 2.39E-02 3.01 E-02 0.005 5.34E-03 1.72E-03 2.80E-03 4.98E-03 7.89E-03 1.02E-02 0.01 3.02E-03 5.75E-04 1.13E-03 2.68E-03 4.90E-03 6.64E-03 0.015 2.08E-03 2.57E-04 5.75E-04 1.72E-03 3.63E-03 5.20E-03 0.03 9.23E-04 4.70E-05 1.29E-04 5.66E-04 1.74E-03 3.01 E-03 0.05 4.01E-04 1.07E-05 3.28E-05 1.74E-04 7.55E-04 1.55E-03 0.075 1.73E-04 2.88E-06 9.37E-06 5.58E-05 2.96E-04 7.45E-04 0.1 8.61 E-05 1.11 E-06 3.57E-06 2.25E-05 1.32E-04 3.95E-04 0.15 2.78E-05 2.76E-07 8.60E-07 5.58E-06 3.68E-05 1.34E-04 0.3 2.83E-06 2.19E-08 6.93E-08 4.25E-07 2.96E-06 1.25E-05 0.5 4.39E-07 2.88E-09 1.04E-08 6.54E-08 4.83E-07 1.82E-06 0.75 1.05E-07 5.83E-10 2.25E-09 1.46E-08 1.20E-07 4.70E-07

1. 4.18E-08 2.49E-10 7.77E-10 5.20E-09 4.56E-08 2.01 E-07 1.5 1.32E-08 1.60E-10 2.35E-10 1.31 E-09 1.20E-08 6.73E-08
3. 2.04E-09 1.11 E-1 0 1.27E-10 2.07E-10 1.32E-09 9.51 E-09
5. 4.59E-10 1.11 E-1 0 1.21 E-10 1.72E-10 3.05E-10 1.92E-09 7.5 1.25E-10 1.11 E-10 1.21 E-10 1.72E-10 1.79E-10 5.42E-10
10. 4.59E-11 1.11 E-10 1.11 E-1 0 1.72E-10 1.72E-10 2.76E-10 31

Table A-2. Amplification Functions for GGNS. (EPRI, 2014)

Median Sigma Median Sigma Median Sigma Median Sigma PGA AF In(AF} 25 Hz AF In(AF} 10 Hz AF In(AF} 5 Hz AF In(AF}

1.00E-02 1.53E+00 5.75E-02 1.30E-02 1.19E+00 5.74E-02 1.90E-02 1.14E+00 8.61 E-02 2.09E-02 1.60E+00 1.08E-01 4.95E-02 1.02E+00 6.60E-02 1.02E-01 5.44E-01 6.87E-02 9.99E-02 9.16E-01 1.12E-01 8.24E-02 1.49E+00 1.18E-01 9.64E-02 8.72E-01 6.94E-02 2.13E-01 5.00E-01 7.34E-02 1.85E-01 8.47E-01 1.18E-01 1.44E-01 1.42E+00 1.22E-01 1.94E-01 7.51 E-01 7.36E-02 4.43E-01 5.00E-01 7.89E-02 3.56E-01 7.65E-01 1.25E-01 2.65E-01 1.34E+00 1.27E-01 2.92E-01 6.87E-01 7.78E-02 6.76E-01 5.00E-01 8.37E-02 5.23E-01 7.09E-01 1.30E-01 3.84E-01 1.27E+00 1.33E-01 3.91 E-01 6.43E-01 8.10E-02 9.09E-01 5.00E-01 8.71 E-02 6.90E-01 6.64E-01 1.35E-01 5.02E-01 1.21 E+OO 1.38E-01 4.93E-01 6.09E-01 8.36E-02 1.15E+00 5.00E-01 9.01 E-02 8.61 E-01 6.26E-01 1.39E-01 6.22E-01 1.16E+00 1.43E-01 7.41 E-01 5.49E-01 8.72E-02 1.73E+00 5.00E-01 9.34E-02 1.27E+00 5.52E-01 1.46E-01 9.13E-01 1.06E+00 1.54E-01 1.01 E+OO 5.05E-01 9.22E-02 2.36E+00 5.00E-01 9.85E-02 1.72E+00 5.00E-01 1.52E-01 1.22E+00 9.79E-01 1.65E-01 1.28E+00 5.00E-01 9.62E-02 3.01 E+OO 5.00E-01 1.02E-01 2.17E+00 5.00E-01 1.58E-01 1.54E+00 9.07E-01 1.74E-01 1.55E+00 5.00E-01 1.00E-01 3.63E+00 5.00E-01 1.05E-01 2.61 E+OO 5.00E-01 1.61 E-01 1.85E+00 8.52E-01 1.83E-01 Median Sigma Median Sigma Median Sigma 2.5 Hz AF In(AF} 1 Hz AF In(AF} 0.5 Hz AF In(AF}

2.18E-02 1.76E+00 1.13E-01 1.27E-02 2.33E+00 1.75E-01 8.25E-03 2.25E+00 1.85E-01 7.05E-02 1.68E+00 1.14E-01 3.43E-02 2.26E+00 1.70E-01 1.96E-02 2.23E+00 1.80E-01 1.18E-01 1.64E+00 1.15E-01 5.51 E-02 2.23E+00 1.67E-01 3.02E-02 2.23E+00 1.80E-01 2.12E-01 1.58E+00 1.17E-01 9.63E-02 2.18E+00 1.63E-01 5.11 E-02 2.23E+00 1.81 E-01 3.04E-01 1.53E+00 1.19E-01 1.36E-01 2.15E+00 1.59E-01 7.10E-02 2.23E+00 1.82E-01 3.94E-01 1.49E+00 1.21 E-01 1.75E-01 2.12E+00 1.57E-01 9.06E-02 2.23E+00 1.83E-01 4.86E-01 1.45E+00 1.23E-01 2.14E-01 2.09E+00 1.54E-01 1.10E-01 2.23E+00 1.84E-01 7.09E-01 1.37E+00 1.25E-01 3.10E-01 2.04E+00 1.51 E-01 1.58E-01 2.23E+00 1.87E-01 9.47E-01 1.30E+00 1.29E-01 4.12E-01 2.02E+00 1.50E-01 2.09E-01 2.23E+00 1.88E-01 1.19E+00 1.24E+00 1.35E-01 5.18E-01 2.00E+00 1.51 E-01 2.62E-01 2.23E+00 1.89E-01 1.43E+00 1.21 E+OO 1.37E-01 6.19E-01 1.98E+00 1.51 E-01 3.12E-01 2.23E+00 1.90E-01 32

Tables A-3a and A-3b are tabular versions of the typical amplification factors provided in Figures 2.3.6-1 and 2.3.6-2. Values are provided for two input motion levels at approximately 10-4 and 10-5 mean annual frequency of exceedance. These factors are unverified and are provided For Information Only. The figures should be considered the governing information.

33

Table A-3a. Median AFs and sigmas for Model 1, Profile 1, for 2 PGA levels.

For Information Only M1 P1 K1 Rock PGA=0.0964 M1 P1 K1 PGA=0.194 Freq. med. Freq. med.

(Hz) Soil SA AF sigma In{AF) (Hz) Soil SA AF sigma In{AF) 100.0 0.092 0.958 0.056 100.0 0.158 0.815 0.062 87.1 0.092 0.939 0.056 87.1 0.158 0.795 0.062 75.9 0.093 0.908 0.056 75.9 0.158 0.761 0.062 66.1 0.093 0.849 0.056 66.1 0.159 0.699 0.063 57.5 0.093 0.749 0.056 57.5 0.159 0.599 0.063 50.1 0.093 0.638 0.057 50.1 0.159 0.500 0.063 43.7 0.094 0.546 0.057 43.7 0.160 0.425 0.063 38.0 0.095 0.495 0.057 38.0 0.161 0.389 0.064 33.1 0.096 0.468 0.058 33.1 0.164 0.372 0.065 28.8 0.098 0.471 0.059 28.8 0.167 0.380 0.067 25.1 0.101 0.475 0.061 25.1 0.172 0.387 0.070 21.9 0.105 0.510 0.062 21.9 0.178 0.421 0.073 19.1 0.111 0.537 0.068 19.1 0.187 0.448 0.081 16.6 0.119 0.596 0.076 16.6 0.199 0.497 0.090 14.5 0.128 0.659 0.087 14.5 0.214 0.559 0.100 12.6 0.138 0.724 0.100 12.6 0.232 0.622 0.116 11.0 0.148 0.784 0.097 11.0 0.247 0.679 0.113 9.5 0.159 0.873 0.121 9.5 0.266 0.765 0.125 8.3 0.173 1.022 0.138 8.3 0.288 0.897 0.142 7.2 0.188 1.176 0.145 7.2 0.315 1.046 0.147 6.3 0.198 1.307 0.138 6.3 0.334 1.180 0.144 5.5 0.204 1.403 0.117 5.5 0.345 1.279 0.127 4.8 0.208 1.450 0.088 4.8 0.354 1.339 0.096 4.2 0.209 1.495 0.087 4.2 0.357 1.393 0.091 3.6 0.205 1.496 0.087 3.6 0.351 1.407 0.087 3.2 0.204 1.574 0.110 3.2 0.347 1.475 0.111 2.8 0.199 1.608 0.096 2.8 0.343 1.536 0.100 2.4 0.195 1.704 0.105 2.4 0.335 1.627 0.109 2.1 0.189 1.801 0.104 2.1 0.325 1.737 0.109 1.8 0.184 1.953 0.096 1.8 0.315 1.880 0.094 1.6 0.170 2.083 0.116 1.6 0.290 1.999 0.114 1.4 0.166 2.347 0.099 1.4 0.280 2.242 0.110 1.2 0.152 2.426 0.135 1.2 0.263 2.390 0.136 1.0 0.131 2.312 0.148 1.0 0.226 2.278 0.135 0.91 0.129 2.481 0.124 0.91 0.222 2.459 0.122 0.79 0.105 2.217 0.139 0.79 0.183 2.240 0.140 0.69 0.099 2.329 0.163 0.69 0.170 2.326 0.159 0.60 0.098 2.625 0.132 0.60 0.167 2.625 0.124 0.52 0.080 2.518 0.198 0.52 0.137 2.534 0.196 0.46 0.068 2.531 0.173 0.46 0.115 2.552 0.177 0.10 0.003 2.388 0.152 0.10 0.005 2.398 0.159 34

Table A-3b. Median AFs and sigmas for Model 2, Profile 1, for 2 PGA levels.

For Information Only M2P1K1 PGA=0.0964 M2P1K1 PGA=0.194 Freq. med. Freq. med.

(Hz) Soil SA AF sigma In(AF) (Hz) Soil SA AF sigma In(AF) 100.0 0.097 1.010 0.045 100.0 0.170 0.875 0.046 87.1 0.097 0.991 0.045 87.1 0.170 0.854 0.046 75.9 0.098 0.958 0.045 75.9 0.170 0.818 0.046 66.1 0.098 0.896 0.045 66.1 0.170 0.751 0.046 57.5 0.098 0.791 0.045 57.5 0.171 0.644 0.046 50.1 0.098 0.673 0.045 50.1 0.172 0.538 0.046 43.7 0.099 0.577 0.046 43.7 0.173 0.458 0.047 38.0 0.100 0.525 0.046 38.0 0.175 0.421 0.047 33.1 0.102 0.497 0.046 33.1 0.178 0.404 0.049 28.8 0.105 0.503 0.047 28.8 0.182 0.414 0.051 25.1 0.108 0.509 0.048 25.1 0.188 0.425 0.052 21.9 0.113 0.549 0.052 21.9 0.196 0.465 0.058 19.1 0.120 0.582 0.058 19.1 0.208 0.500 0.066 16.6 0.129 0.642 0.064 16.6 0.224 0.558 0.074 14.5 0.140 0.719 0.074 14.5 0.242 0.631 0.083 12.6 0.151 0.789 0.083 12.6 0.261 0.699 0.089 11.0 0.161 0.853 0.082 11.0 0.278 0.763 0.090 9.5 0.171 0.944 0.098 9.5 0.296 0.850 0.096 8.3 0.189 1.119 0.120 8.3 0.326 1.015 0.116 7.2 0.204 1.276 0.126 7.2 0.354 1.177 0.127 6.3 0.214 1.413 0.122 6.3 0.371 1.313 0.126 5.5 0.219 1.505 0.101 5.5 0.381 1.412 0.102 4.8 0.223 1.556 0.092 4.8 0.388 1.470 0.094 4.2 0.222 1.591 0.102 4.2 0.388 1.514 0.105 3.6 0.216 1.579 0.106 3.6 0.378 1.514 0.108 3.2 0.215 1.657 0.106 3.2 0.370 1.575 0.108 2.8 0.206 1.663 0.092 2.8 0.359 1.608 0.089 2.4 0.202 1.760 0.098 2.4 0.350 1.700 0.095 2.1 0.194 1.852 0.108 2.1 0.337 1.800 0.111 1.8 0.191 2.027 0.109 1.8 0.330 1.970 0.111 1.6 0.177 2.158 0.126 1.6 0.304 2.092 0.128 1.4 0.171 2.424 0.098 1.4 0.292 2.336 0.097 1.2 0.153 2.448 0.138 1.2 0.266 2.415 0.139 1.0 0.133 2.340 0.155 1.0 0.230 2.316 0.143 0.91 0.129 2.489 0.134 0.91 0.224 2.472 0.132 0.79 0.105 2.212 0.139 0.79 0.182 2.226 0.139 0.69 0.099 2.327 0.161 0.69 0.169 2.320 0.157 0.60 0.098 2.627 0.141 0.60 0.167 2.623 0.138 0.52 0.080 2.517 0.198 0.52 0.137 2.530 0.199 0.46 0.068 2.520 0.167 0.46 0.114 2.529 0.165 0.10 0.003 2.387 0.154 0.10 0.005 2.394 0.161 35

NUCLEAR QUALITY RELATED I

EN-L1-106 REV. 13 MANAGEMENT MANUAL NRC Corres ondence ATTACHMENT 9.4 NRC SUBMITTAL REVIEW Sheet 1 of 2 {Typical}

Design Engineering / Tori certification Per EN-L1-1 06 Att. 9.5 Liggans-Robinson Supervisor, Design Engineering certification/concurrence Per EN-L1-1 06 Att. 9.5

/ Fred Hopkins Director Regulatory & concurrence Performance Improvement /

Tom Coutu N/A S ection II Correspondence s creening Does this letter contain commitments? If "yes," identify the commitments with due Yes 0 dates in the submittal and in Section III. When fleet letters contain commitments, a No ~

PCRS LO (e.g., LO-LAR, LO-WT) should be initiated with a CA assigned to each applicable site to enter the commitments into the site's commitment management system.

Does this letter contain any information or analyses of new safety issues performed at NRC Yes 0 request or to satisfy a regulatory requirement? If "yes," reflect requirement to update the No ~

UFSAR in Section III.

Does this letter require any document changes (e.g., procedures, DBDs, FSAR, TS Bases, Yes 0 etc.), if approved? If "yes," indicate in Section III an action for the responsible No ~

department to determine the affected documents. (The Correspondence Preparer may indicate the specific documents requiring revision, if known or may initiate an action for review.)

Does this letter contain information certified accurate? If "yes," identify the information Yes ~

and document certification in an attachment. (Attachment 9.5 must be used.) No D EN-L1-106 REV 13

NUCLEAR QUALITY RELATED EN-L1-106 REV. 13 MANAGEMENT INFORMA110NAL USE MANUAL NRC Corres ondence ATTACHMENT 9.4 NRC SUBMITTAL REVIEW Sheet 2 of 2 Section III Actions and Commitments Required Actions Due Date Responsible Dept.

Note: Actions needed upon approval should be captured in the appropriate action tracking system N/A N/A N/A Commitments Due Date Responsible Dept.

Note: When fleet letters contain commitments, a PCRS LO should be initiated with a CA assigned to each applicable site to enter the commitments into the site's commitment management system.

N/A N/A N/A S ectlon IV F"InaIDocument S*Ignofff or Su b mltta Correspondence Preparer Tori Liggans-Robinson / See EN-L1-106 Att. 9.5 Final Submittal Review (optional) Fred Hopkins / See EN-L1-106 AU. 9.5 Responsible Department Head Jeffery A. Seiter I ~~

EN-LI-106 REV 13

~Entergy NUCLEAR MANAGEMENT QUAUTY RELATED EN-Ll-106 I REV. 13 INFORMA110NAL USE MANUAL NRC Correspondence ATTACHMENT 9.5 CER11FICA110N REFERENCE FORM Sheet 1 of 1 Letter Number: I GNRO-2014/00027

Subject:

Entergy Seismic Hazard and Screening Report (CEUS Sites), Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident Certifiable Statement(s): Use one of the following methods to identify certifiable statements in the table below:

1 Identify location in submittal (e.g., page 3, para 2, sentence 1) OR, 2 Paste in the exact words of the statement(s) OR, 3 State "see attachment" and attach a copy of the correspondence with the certifiable statements indicated (e.g., by redlining, highlighting, or underlining, etc.).

Each statement or section of information being certified should be uniquely numbered to correspond with the supporting documentation listed below.

Objective Evidence or Basis of Peer Review: List the supporting documents in the table below and attach a copy of the documents OR give basis of peer review. Large documents need not be attached.

Certifiable Statement(s) Objective Evidence or Basis of Peer Review GNRO-2014/00027

Attachment:

GGNS Seismic Grand Gulf Seismic Hazard Report, AREVA Hazard and Screening Report (CEUS Sites) Document Number 51-9218842-003 Individual certifying the statement(s): Certification may be documented using e-mail, telecom, "sign off" sheet, or inter-office memorandum. The form of documentation should specifically identify the information bein~rtified Tori L.

Name RObinson~~~eSign Department Engineering 3-21-14 Date Peer Review: Prior to signing for certification, determine if a Peer Review is required per section 5.4[2](c). Indicate "N/A" if not required.

Fred HOPki~p---------;De-sr9h Engineering 3-21-14 Name ~ ~ Department Date EN-L1-106 REV 13

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