ML093080034

Slides for Oconee Nuclear Station, Units 1, 2, and 3 - Meeting Slides - External Flood NRC Technical Meeting

ML093080034
Person / Time
Site:	Oconee
Issue date:	10/28/2009
From:	Duke Energy Carolinas
To:	Office of Nuclear Reactor Regulation
Arce, Jeannette 415-1596
Shared Package
ML093080062	List: ML093080034
References
FOIA/PA-2013-0213, FOIA/PA-2015-0348
Download: ML093080034 (36)

Text

-. .

OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY Oconee Nuclear Station External Flood NRC Technical Meeting Rockville, MD 10/28/09 Withhold from public disclosure 1 under 10 CFR 2.390 OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY

OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY Duke Attendees

~Rich Freudenberger, Manager ONS Safety Assurance Manager

~Jeff Thomas, Corporate Regulatory Compliance Manager

~ Tim Brown, ONS Project Manager

~Ray Mc Coy, ONS Principal Engineer

~Chris Ey, Manager Civil Engineering, HDR

~Andy Mc Coy, Ph.D., Water Resources Engineer, HDR Withhold from public disclosure 2 under 10 CFR 2.390 OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY

OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY Agenda

~Overview of Sensitivity Studies

~HEC-RAS Results

~HEC-RAS Model Confidence

~Selection & Justification of 20 Model Cases

~HEC-RAS Results and Input to Selected 20 Model Cases

~20 Model Highlights & Results

~Summary Withhold from public disclosure 3 under 10 CFR 2.390 OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY

OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY Sensitivity Studies

~Jocassee

-Breach Size

-Time to Failure

~Keowee

-Failure Sequence

-Breach Size

-Time to Failure

-West Saddle Dam Failure Withhold from public disclosure 4 under 10 CFR 2.390 OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY

OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY HEC-RAS Results Keowee Headwater 860 850

.~

-~

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~ M......

• 840 830 I.* ***

~

820 810 800 o 20 40 60 80 100 o Withhold from public disclosure 5 under 10 CFR 2.390 OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY

OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY Duke HEC-RAS Results wI Energy W. Saddle Dam Failure Keowee Headwater 850 845 840 835 830

• 825 820 815 810 805 800 50 60 70 80 90 100 110 Withhold from public disclosure 6 under 10 CFR 2.390 OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY

OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY HEC-RAS Results Oconee Intake Canal Dike Headwater 835 ,

830

.I-W 825 820 L.....-

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815 -

810 -

805 800 .J -1 a 20 40 60 80 100 120 Withhold from public disclosure 7 under 10 CFR 2.390 OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY

OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY Duke HEC-RAS Results wI Energy w. Saddle Dam Failure Oconee Intake Canal Dike Headwater 835 830 * **

825 *** ................... .... .......... ....

820 815 810 805 800 50 60 70 80 90 100 110 Withhold from public disclosure 8 under 10 CFR 2.390 OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY

OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY HEC-RAS Results Keowee Tailrace 830 810

~....#l~..¥J¥ .... ........ .......... ......

• 790 770 I. ...~ - -. _.

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+.

750 730 710 690 670 a 20 40 60 80 100 20 Withhold from public disclosure 9 under 10 CFR 2.390 OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY

OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY HEC-RAS Results wi W. Saddle Dam Failure Keowee Tailrace 830 810 790 * ***

770

• 750 730 710 690 670 50 60 70 80 90 100 110 Withhold from public disclosure 10 under 10 CFR 2.390 OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY

OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY HEC-RAS Model Confidence

~ Model confidence is measured by conservation of mass volume.

~ A key area of interest is at the connecting canal confluence with the Keowee Arm of the reservoir.

~ Mass volume calculated by integrating the discharge

-hydrographs for the various cases.

~ Integration of the Keowee River inflow hydrograph should equal the summation of the integrated hydrographs for the Keowee Dam and the Connecting Canal.

Withhold from public disclosure 11 under 10 CFR 2.390 OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY

OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY HEC-RAS Model Confidence Hydrograph Volume (cfs-hrs)

Connecting Keowee River Ke owee Dam& Net Hydrograph KeoweeDam Model Keowee Dam Connecting Canal Flow Inflow Connecting Canal Integration at Dam- Flow 0/0 0/0 Inflow Canal Inflow (Upstream) Volume River Junction Case 1 18,695,218 11,618,099 -7,077,118 18,695,218 0.7 62.1% 37.9%

Case 2 18,791,578 11,680,136 -7,111,442 18,791,578 0.1 62.2% 37.8%

Case 3 18,804,194 11,848,448 -6,955,747 18,804,195 -1.1 63.0% 37.0%

Mar-09 18,833,982 13,919,781 -4,914,201 18,833,982 -0.3 73.9% 26.1%

I HEC RAS Model Schematic I Keowee River Arm Inflow Connecting Canal Inflow to Little River Arm

. Canal Junction Keowee Dam Inflow I Keowee Dam I

Withhold from public disclosure 12 under 10 CFR 2.390 OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY

OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY Selection of 20 Model Cases J ocas s ee Dam Overtopping Breach Bottom Breach Bottom Breach Side Slopes (ft Time to Initial Piping Case Initiation .Elevation

.Elevation (ft msl) Width (ft) per ft) Failure (hrs) .Elevation (ft msl)

(ft msl)

I 800 250 1:1 2.6 1020 NA 2 800 425 1.55:1 & 0.7:1 2.8 1020 NA 3 800 600 1.55:1 & 0.7:1 3 1020 NA Keo~e Dam Including West Saddle Dam Breach Overtopping Breach Bottom Breach Bottom Breach Side Slopes (ft Time to Initial Piping Case Initiation Elevation

.Elevation (ft msl) Width (ft) per ft) Failure (hrs) Elevation (ft msl)

(ft msl) 1 670 500 1:1 2.8 NA 817 2 670 500 1:1 2.8 NA 817 3 670 500 1:1 2.8 NA 817 ONS Intake Canal Dike Overtopping Breach Bottom Breach Bottom Breach Side Slopes (ft Time to Initial Piping Case Initiation .Elevation

.Elevation (ft msl) Width (ft) per ft) Failure (hrs) .Elevation (ft msl)

(ft msl) 1 715.5 200 1:1 0.9 NA 817 2 715.5 200 1:1 0.9 NA 817 3 715.5 200 1:1 0.9 NA 817 Little River Dam Overtopping Breach Bottom Breach Bottom Breach Side Slopes (ft Time to Initial Piping Case Initiation Elevation Elevation (ft msl) Width (ft) per ft) Failure (hrs) Elevation (ft msl)

(ft msl) 1 670 290 1:1 1.9 NA 817 2 670 290 1:1 1.9 NA 817 3 670 290 1:1 1.9 NA 817 Withhold from public disclosure 13 under 10 CFR 2.390 OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY

OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY Duke Justification for 20 Energy Cases Selected

~Jocassee

• Case 1 - Modified Original Case (1992) o Bottom Breach width: 250 ft. (unchanged) o Bottom Breach elevation: 800 ft. MSL (unchanged) o Slope: 1:1 (unchanged) o Revised reservoir elevation from 1108 ft. to 1110 ft. MSL o Revised time to failure from 4 to 2.6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> (Froehlich value

-2.2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />) o Piping elevation: 1020 ft (Captures probable failure initiation at West Abutment) o Failure Progression: Sine Wave (Conservative portrayal of material loss through breach)

Withhold from public disclosure 14 under 10 CFR 2.390 OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY

OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY Justification for 20 Cases Selected

~Jocassee

• Case 2 - Conservative Case o Bottom Breach width: 425 ft (Average of Case 1 & 3) o Time to failure: 2.8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> (Adopted value between Froehlich and Walder & O'Connor)

• Case 3 - Worst Case o Bottom Breach width: 600 ft. (Simulates maximum bottom breach width of dam fill) o West Slope: 1.55:1 (Captures probable failure initiation at West Abutment) o East Slope: 0.7:1 (Froehlich suggested value) o Time to failure: 3.0 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> (Walder & O'Connor)

Withhold from public disclosure 15 under 10 CFR 2.390 OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY

OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY Justification for 20 Cases Selected

~ Keowee - All parameters held constant for all three cases

• Main Dam o Reservoir elevation: 800 ft. MSL o Bottom Breach elevation: 670 ft. MSL (Tailrace elevation) o Bottom Breach width: 500 ft (Site constraint) o Both side slopes: 1:1 (Froehlich suggested value) o Time to failure: 2.8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> (Froehlich suggested value adjusted to size of dam) o Overtopping trigger: 817 ft. MSL - 2 ft above crest (Based on downstream slope velocity profiles and soils) o Failure Progression: Sine Wave (Conservative portrayal of material loss through breach)

Withhold from public disclosure 16 under 10 CFR 2.390 OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY

OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY Justification for 20 Cases Selected

~Keowee

• West Saddle Dam o Bottom Breach elevation: 795 ft. MSL (Elevation of toe) o Bottom Breach width: 1680 ft (800/0 of total width engineering judgment) o Both side slopes: Vertical (Facilitates model input) o Time to failure: 0.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> (Based on velocity studies)

• Intake Dike o Bottom Breach elevation: 715.5 ft. MSL (Elevation of toe) o Bottom Breach width: 200 ft (Site constraint) o Both side slopes: 1:1 (Froehlich suggested value) o Time to failure: .9 hr. (Proportional to Main Dam breach area)

Withhold from public disclosure 17 under 10 CFR 2.390 OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY

OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY Justification for 20 Cases Selected

~Keowee

• Little River Dam o Bottom Breach elevation: 670 ft. MSL (Elevation of toe) o Bottom Breach width: 290 ft (Site constraint) o Both side slopes: 1: 1 (Froehlich suggested value) o Time to failure: 1.9 hours1.041667e-4 days <br />0.0025 hours <br />1.488095e-5 weeks <br />3.4245e-6 months <br /> (Proportional to Main Dam breach area)

Withhold from public disclosure 18 under 10 CFR 2.390 OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY

OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY HEC-RAS Results for Selected 20 Cases

~ Case 1 (Modified Original Case)

~ Keowee Headwater - 831.2 ft. MSL (16.2 ft. above dam crest)

~ Keowee Tailrace - 772.5 ft. MSL (2.5 ft. below T8 basement)

~ Intake Dike Headwater - 821.8 ft. MSL (6.8 ft. above dike crest)

~ Case 2 (Conservative Case)

~ Keowee Headwater - 835.3 ft. MSL (20.3 ft. above dam crest)

~ Keowee Tailrace - 776.7 ft. MSL (1.7 ft. above T8 basement)

~ Intake Dike Headwater - 822.7 ft. MSL (7.7 ft. above dike crest)

~ Case 3 (Worst Case)

~ Keowee Headwater - 839.4 ft. MSL (24.4 ft. above dam crest)

~ Keowee Tailrace - 780.0 ft. MSL (5.0 ft. above T8 basement)

~ Intake Dike Headwater - 823.1 ft. MSL (8.1 ft. above dike crest)

Withhold from public disclosure 19 under 10 CFR 2.390 OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY

OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY HEC-RAS Results for Selected 20 Cases Jocassee-Keowee Dam Breach Study Keowee Dam and ONS Dike Stage Hydrographs 2D Model Cases - HEC RAS Results 850 840 I

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Withhold from public disclosure 20 under 10 CFR 2.390 OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY

OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY HEC-RAS Input to Selected 20 Cases Input to 6,000,000

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Withhold from public disclosure 27 under 10 CFR 2.390 OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY

OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY HEC-RAS Results vs. 20 Model Results Scenario Breaching KeoweeDam Intake Dike HEC-RAS 20 HEC-RAS 20 Elevation Decimal Time Elevation Decimal Time Elevation Decimal Time Elevation Decimal Time Case 1 817 2.28 817 2.13 817 3.03 817 3.05 Case 2 817 2.25 817 2.11 817 2.93 817 2.97 Case 3 817 2.20 817 2.08 817 2.87 817 2.89 Scenario Maximum Water Surfaces Keowee Dam Intake Dike HEC-RAS 20 HEC-RAS 20 Elevation Decimal Time Elevation Decimal Time Elevation Decimal Time Elevation Decimal Time Case 1 831.2 3.50 834.7 3.05-3.50 821.8 3.33 821.9 3.43 Case 2 835.3 3.50 837.7 3.05-3.50 822.7 3.33 822.5 3.35 Case 3 839.4 3.17 841.6 3.05-3.50 823.1 3.17 823.0 3.28 Scenario Maximum Water Surfaces Swale Tailwater HEC-RAS 20 HEC-RAS 20 Elevation Decimal Time Elevation Decimal Time Elevation Decimal Time Elevation Decimal Time Case 1 826.6 4.00 826.6 4.08 772.3 5.33 799.7 4.63 Case 2 828.6 4.00 827.7 4.05 776.7 5.00 803.2 4.48 Case 3 830.8 3.83 829.0 3.93 780.0 4.83 807.2 4.25 Withhold from public disclosure 28 under 10 CFR 2.390 OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY

OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY HEC-RAS Results vs. 20 Model Results Scenario Total Volume Calculations Through Boundaries Over 10-hr(acre-ft)

Inflow Percent Outflow Percent HEC*RAS 20 HEC-RAS 20 Case 1 1,328,806 1,364,320 2.67 1,424,010 1,536,862 7.92 Case 2 1,370,834 1,369,540 -0.09 1,477,262 1,589,787 7.62 Case 3 1,394,457 1,393,885 -0.04 1,506,357 1,624,993 7.88 Withhold from public disclosure 29 under 10 CFR 2.390 OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY

OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY 2D Model Draft Results Case 1 Withhold from public disclosure 30 under 10 CFR 2.390 OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY

OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY 2D Model Draft Results Case 1 Withhold from public disclosure 31 under 10 CFR 2.390 OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY

OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY 2D Model Draft Results Case 2 Water Deoth(ftl:

Withhold from public disclosure 32 under 10 CFR 2.390 OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY

OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY 2D Model Draft Results Case 2 Withhold from public disclosure 33 under 10 CFR 2.390 OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY

OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY 2D Model Draft Results Case 3 Water Deoth(ftJ:

Withhold from public disclosure 34 under 10 CFR 2.390 OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY

OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY 2D Model Draft Results Case 3 1 2 3 4 5 6 7 8 9 10 Withhold from public disclosure 35 under 10 CFR 2.390 OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY

OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY Dulce Summary Energy

~ 101 HEC-RAS Sensitivity cases evaluated.

~Confidence in HEC-RAS model is high, based on mass volume integration of inflow vs. outflow at the model boundaries.

~20 model created, incorporating the Oconee site, model has over 40,000 elements.

~Cases selected for 20 model encompass a reasonable range of pertinent parameters.

~20 model results compare favorably to the HEC-RAS results, except for Keowee tailrace elevation.

Withhold from public disclosure 36 under 10 CFR 2.390 OFFICIAL USE ONLY - SENSITIVE-PROPRIETARY