L-MT-13-099, Response to NRC Request for Information Re 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

Response to NRC Request for Information Re 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

ML13304B167
Person / Time
Site:	Monticello
Issue date:	10/31/2013
From:	Fili K Northern States Power Co, Xcel Energy
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
L-MT-13-099
Download: ML13304B167 (11)

Text

Xcel Energy October 31, 2013 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Monticello Nuclear Generating Plant Docket No. 50-263 Renewed Facility Operating License No. DPR-22 Monticello Nuclear Generating Plant 2807 W County Road 75 Monticello, MN 55362 L-MT-13-099 10 CFR 50.54(f)

NSPM'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

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, ADAMS Accession No. ML12056A046.

2.

NRC Letter, "Endorsement of EPRI Final Draft Report 1025287, 'Seismic Evaluation Guidance,"' dated February 15, 2013, ADAMS Accession No. ML12319A074.

3.

Electric Power Research Institute (EPRI) Report Number 1025287, "Seismic Evaluation Guidance: Screening, Prioritization and Implementation Details (SPID) for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic," dated November 2012, ADAMS Accession No. ML12333A170.

4.

Nuclear Energy Institute (NEI) letter to NRC, "Proposed Path Forward for NTTF Recommendation 2.1: Seismic Reevaluations," dated April 9, 2013, ADAMS Accession No. ML13101A379.

5.

NRC Letter, "EPRI Final Draft Report XXXXXX, 'Seismic Evaluation Guidance: Augmented Approach for the Resolution of 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.

Document Control Desk Page 2

6.

NSPM Letter to NRC, "Request Commitment Change for 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," dated September 12, 2013, ADAMS Accession No. ML13255A480.

On March 12, 2012, the NRC Staff issued Reference 1 to all power reactor licensees and holders of construction permits in active or deferred status. Enclosure 1 of Reference 1 contains specific Requested Actions, Requested Information, and Required Responses associated with Near-Term Task Force (NTTF) Recommendation 2.1, Seismic Evaluations. Enclosure 1 of Reference 1 requested each addressee in the Central and Eastern United States (CEUS) to submit a written response consistent with the requested seismic hazard evaluation information (items 1 through 7) by September 12, 2013. On February 15, 2013, NRC issued Reference 2, endorsing the Reference 3 industry guidance for responding to Reference 1. Section 4 of Reference 3 identifies the detailed information to be included in the seismic hazard evaluation submittals.

On April 9, 2013, NEI submitted Reference 4 to the NRC, requesting NRC agreement to delay submittal of some of the CEUS seismic hazard evaluation information so that an update to the EPRI (2004, 2006) 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 (items 3a and 3b in Section 4 of Reference 3) be submitted to NRC by September 12, 2013, with the remaining seismic hazard and screening information submitted to NRC by March 31, 2014. In Reference 5, the NRC agreed with this recommendation.

The enclosure to this letter contains the requested description of subsurface materials and properties, and base case velocity profiles for the Monticello Nuclear Generating Plant (MNGP). The information provided in the enclosure to this letter is an interim product of seismic hazard development efforts being performed for the industry by EPRI. The complete and final seismic hazard reports for MNGP will be provided to the NRC in the seismic hazard reevaluation submittals by March 31, 2014 in accordance with Reference 5.

This letter completes the commitment made in the Northern States Power Company, a Minnesota corporation (NSPM), d/b/a Xcel Energy, letter dated September 12, 2013 to submit the information identified in Items 3.a and 3.b for base case velocity profile and the description of subsurface materials and properties in Section 4 of Reference 3.

If there are any questions or if additional information is needed, please contact Ms. Jennie Wike, Licensing Engineer, at 612-330-5788.

Document Control Desk Page 3 Summary of Commitments This letter makes no new commitments and no revisions to existing commitments.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on October 31, 2013.

Karen D. Fili Site Vice President, Monticello Nuclear Generating Plant Northern States Power Company - Minnesota Enclosure cc:

Administrator, Region Ill, USNRC Director of Nuclear Reactor Regulation (NRR), USNRC Project Manager, MNGP, USNRC Resident Inspector, MNGP, USNRC

ENCLOSURE Monticello Nuclear Generating Plant Subsurface Materials and Properties, and Base Case Velocity Profiles 7 Pages to Follow

L-MT-13-099 Enclosure ENCLOSURE Monticello Nuclear Generating Plant NSPM Subsurface Materials and Properties, and Base Case Velocity Profiles 1.0 Introduction On March 12, 2012, the NRC Staff issued Reference 1 to all NRC power reactor licensees and holders of construction permits in active or deferred status. of Reference 1 contains specific Requested Actions, Requested Information, and Required Responses associated with Near-Term Task Force (NTTF) Recommendation 2.1, Seismic Evaluations. Enclosure 1 of Reference 1 requested each addressee in the Central and Eastern United States (CEUS) to submit a written response consistent with the requested seismic hazard evaluation information (items 1 through 7) by September 12, 2013. On February 15, 2013, NRC issued Reference 2, endorsing the Reference 3 industry guidance for responding to Reference 1. Section 4 of Reference 3 identifies the detailed information to be included in the seismic hazard evaluation submittals. In a letter dated September 12, 2013 (Reference 4), Northern States Power Company, a Minnesota corporation (NSPM), d/b/a Xcel Energy, committed to submit the information identified in Items 3.a and 3.b for base case velocity profile and the description of subsurface materials and properties in Section 4 of Reference 3.

This enclosure contains the descriptions of subsurface materials and properties, and base case velocity profiles for the Monticello Nuclear Generating Plant (MNGP). The information provided in this enclosure is an interim product of seismic hazard development efforts being performed for the industry by Electric Power Research Institute (EPRI). The complete and final seismic hazard reports for MNGP will be provided to the NRC in the seismic hazard reevaluation submittals by March 31, 2014.

2.0 Subsurface Materials and Properties, and Base Case Velocity Profiles The basic information used to create the site geologic profile at the MNGP was taken from References 5, 6, and 10. These references include boring logs that indicate approximately 100 feet of sand, silt, and clay overlying weathered sedimentary rock and granite. Three profiles were used to represent site uncertainties, as shown in Table 2 and Figure 1 of this enclosure. Profile P3 models depth to hard rock of 92 feet, with Profiles P1 and P2 representing uncertainty in depth to hard rock with a depth of about 600 feet, and alternative shear-wave velocities at deep depths. No information was available regarding measurement of shear-wave velocities at MNGP, as this information was not Page 1 of 7

L-MT 099 Enclosure NSPM recorded in the original site borings. Table 1 indicates the site geotechnical profile for the MNGP.

The Safe Shutdown Earthquake (SSE) Control Point is at the surface, and therefore, the profile was modeled up to the surface. For dynamic properties of soft rock layers, modulus and damping curves were represented with two (2) models. The first model used rock curves taken from Reference 7, the second model assumed linear behavior. These dynamic property models were weighted equally. For dynamic properties of sand, gravel, and clay layers, modulus and damping curves were also represented with two (2) models. The first model used soil curves taken from Reference 7, the second model used soil curves taken from References 8 and 9. These dynamic property models were weighted equally. To model the profile, rock modulus and damping curves from Reference 6 were paired with soil modulus and damping curves from Reference 7, and linear rock modulus and damping curves were paired with soil modulus and damping curves from References 8 and 9.

The three (3) base-case shear-wave velocity profiles used to model amplification at the site are shown in Figure 1. Profiles 1, 2, and 3 are weighted 0.4, 0.3, and 0.3, respectively. Thicknesses, depths, and shear-wave velocities (Vs) corresponding to each profile are shown in Table 2.

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L-MT-13-099 Enclosure NSPM Table 1 -Summary of Site Geotechnical Profile for MNGP1 (Reference 5)

Depth Shear Compressional Density2 Wave Range3 Soil/Rock Description (pcf)

Velocity2 Wave Velocity2 (feet)

(fps)

(fps) 0 (930')

Ground Surface Elevation 0-10 Fine to coarse sand with 119-127 NR NR gravel 10-20 Fine to coarse sand with 115-128 NR NR gravel and occasion cobbles 20-40 Medium sand with gravel 112-128 NR NR 40-50 Fine to medium sand with 116 NR NR fine sandy clay lenses transitioning to medium to coarse sand and gravel and silt boulders 50-60 Yellowish-brown grading 123 NR NR to gray grading 60-75 Medium grained quartz NR NR NR sandstone (medium hard),

friable to moderately well cemented 75-90 Decomposed granitic rock NR NR NR (medium soft)90-105 Decomposed diabase NR NR NR (medium soft) 105-110 Weathered granite rock NR NR NR (hard) with secondary quartz NOTES:

(1) Data taken from original construction Boring No. 1 which was near vicinity of power block (2) NR = Not Recorded Poisson's Ratio2 NR NR NR NR NR NR NR NR NR (3) Deepest Structure Foundation Elevation: the base mat of the combined Reactor, Turbine, and auxiliary buildings varies from 5' to 42' below grade (Intake Structure excluded).

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L-MT-13-099 Enclosure NSPM Table 2-Layer Thicknesses, Depths, and Vs for Three Profiles (MNGP)

Profile 1 Profile 2 Profile 3 thickness(ft) depth (ft)

Vs (ftls) thickness(ft) depth (ft)

Vs (ftls)

Thickness(ft) depth (ft)

Vs(ftls) 0 2150 0

1369 0

3376 5.0 5.0 2150 5.0 5.0 1369 5.0 5.0 3376 5.0 10.0 2150 5.0 10.0 1369 5.0 10.0 3376 5.0 15.0 2150 5.0 15.0 1369 5.0 15.0 3376 5.0 20.0 2150 5.0 20.0 1369 5.0 20.0 3376 5.0 25.0 2150 5.0 25.0 1369 5.0 25.0 3376 5.0 30.0 2150 5.0 30.0 1369 5.0 30.0 3376 5.0 35.0 2150 5.0 35.0 1369 5.0 35.0 3376 7.0 42.0 2150 7.0 42.0 1369 7.0 42.0 3376 5.0 47.0 2860 5.0 47.0 1822 5.0 47.0 4491 5.0 52.0 2860 5.0 52.0 1822 5.0 52.0 4491 5.0 57.0 2860 5.0 57.0 1822 5.0 57.0 4491 5.0 62.0 2860 5.0 62.0 1822 5.0 62.0 4491 5.0 67.0 2860 5.0 67.0 1822 5.0 67.0 4491 5.0 72.0 2860 5.0 72.0 1822 5.0 72.0 4491 5.0 77.0 2860 5.0 77.0 1822 5.0 77.0 4491 5.0 82.0 2860 5.0 82.0 1822 5.0 82.0 4491 5.0 87.0 2860 5.0 87.0 1822 5.0 87.0 4491 5.0 92.0 2860 5.0 92.0 1822 5.0 92.0 4491 10.0 102.0 5020 10.0 102.0 2714 10.0 102.0 9285 10.0 112.0 5020 10.0 112.0 2714 10.0 112.0 9285 10.0 122.0 5020 10.0 122.0 2714 10.0 122.0 9285 10.0 132.0 5020 10.0 132.0 2714 10.0 132.0 9285 10.0 142.0 5020 10.0 142.0 2714 10.0 142.0 9285 10.0 152.0 5020 10.0 152.0 2714 10.0 152.0 9285 10.0 162.0 5020 10.0 162.0 2714 10.0 162.0 9285 10.0 172.0 5020 10.0 172.0 2714 10.0 172.0 9285 10.0 182.0 5020 10.0 182.0 2714 10.0 182.0 9285 10.0 192.0 5020 10.0 192.0 2714 10.0 192.0 9285 10.0 202.0 5020 10.0 202.0 2714 10.0 202.0 9285 10.0 212.0 5020 10.0 212.0 2714 10.0 212.0 9285 10.0 222.0 5020 10.0 222.0 2714 10.0 222.0 9285 10.0 232.0 5020 10.0 232.0 2714 10.0 232.0 9285 10.0 242.0 5020 10.0 242.0 2714 10.0 242.0 9285 10.0 252.0 5020 10.0 252.0 2714 10.0 252.0 9285 10.0 262.0 5020 10.0 262.0 2714 10.0 262.0 9285 10.0 272.0 5020 10.0 272.0 2714 10.0 272.0 9285 Page 4 of 7

L -MT 099 Enclosure Profile 1 thickness(ft) depth (ft) 10.0 282.0 10.0 292.0 10.0 302.0 10.0 312.0 10.0 322.0 10.0 332.0 10.0 342.0 10.0 352.0 10.0 362.0 10.0 372.0 10.0 382.0 10.0 392.0 10.0 402.0 10.0 412.0 17.6 429.6 17.6 447.2 17.6 464.8 17.6 482.4 17.6 500.0 91.9 591.9 3280.8 3872.7 Vs (ft/s) thickness(ft) 5020 10.0 5020 10.0 5020 10.0 5020 10.0 5020 10.0 5020 10.0 5020 10.0 5020 10.0 5020 10.0 5020 10.0 5020 10.0 5020 10.0 5020 10.0 5020 10.0 5020 17.6 5020 17.6 5020 17.6 5020 17.6 5020 17.6 5020 91.9 9285 3280.8 NSPM Profile 2 Profile 3 depth (ft)

Vs (ft/s)

Thickness(ft) depth (ft)

Vs (ftls) 282.0 2714 10.0 282.0 9285 292.0 2714 10.0 292.0 9285 302.0 2714 10.0 302.0 9285 312.0 2714 10.0 312.0 9285 322.0 2714 10.0 322.0 9285 332.0 2714 10.0 332.0 9285 342.0 2714 10.0 342.0 9285 352.0 2714 10.0 352.0 9285 362.0 2714 10.0 362.0 9285 372.0 2714 10.0 372.0 9285 382.0 2714 10.0 382.0 9285 392.0 2714 10.0 392.0 9285 402.0 2714 10.0 402.0 9285 412.0 2714 10.0 412.0 9285 429.6 2714 17.6 429.6 9285 447.2 2714 17.6 447.2 9285 464.8 2714 17.6 464.8 9285 482.4 2714 17.6 482.4 9285 500.0 2714 17.6 500.0 9285 591.9 2714 91.9 591.9 9285 3872.7 9285 3280.8 3872.7 9285 Page 5 of 7

L-MT 099 Enclosure Vs profiles for Monticello Site Vs (ft/sec) 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 0

so 100 150 200 250

!+/-:.. 300

..r::.... g. 350 0

400 450 500 550 600 650 3.0 References L L I

i=+/-=

I I

I Figure 1 - V5 profiles for MNGP site Shear-wave velocity (Vs)

NSPM

-Profile 1

-Proflle2

=-Profile 3

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, ADAMS Accession No. ML12056A046.

2. NRC Letter, "Endorsement of EPRI Final Draft Report 1025287, 'Seismic Evaluation Guidance,"' dated February 15, 2013, ADAMS Accession No. ML12319A074.

3. Electric Power Research Institute (EPRI) Report Number 1025287, "Seismic Evaluation Guidance: Screening, Prioritization and Implementation Details (SPID) for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic," dated November 2012, ADAMS Accession No. ML12333A170.

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L-MT 099 Enclosure NSPM

4. NSPM Letter to NRC, "Request Commitment Change for 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," dated September 12, 2013, ADAMS Accession No. ML13255A480.

5. Monticello Nuclear Generating Plant Updated Safety Analysis Report (USAR), Revision 22.

6. MNGP Calculation, Geotechnical Reporl for the Independent Spent Fuel Storage Installation, Report No. CA-07-033, dated May 9, 2005.

7. EPRI Report TR-102293, "Guidelines for Determining Design Basis Ground Motions," Volumes 1-5, dated November 1993.

8. W.J. Silva, N. A. Abrahamson, G.R. Toro, and C. Costantino. Report to Brookhaven National Laboratory, "Description and Validation of the Stochastic Ground Motion Model," dated November 15, 1996, ADAMS Accession No. ML042800294.

9. N.A. Abrahamson, M.A. Walling, W.J. Silva (2008). "Nonlinear Site Amplification Factors for Constraining the NGA Models," Earlhquake Spectra, 24:1, 243-255.

10. NSPM Report, Site Geologic Conditions for Monticello Nuclear Generating Plant (MGNP), transmitted to the Electric Power Research Institute (EPRI) in October 2013.

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