ML13120A132
| ML13120A132 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar, Sequoyah  |
| Issue date: | 04/29/2013 |
| From: | James Shea Tennessee Valley Authority |
| To: | Andrew Hon Plant Licensing Branch II |
| Hon A NRR/DORL/LPL2-2 | |
| References | |
| Download: ML13120A132 (30) | |
Text
Sequoyah and Watts Bar Nuclear Plants NTTF Recommendation 2.1, Flooding Hazard Reevaluation Report Extension Request April 29 2013 April 29, 2013
Agenda Introduction Joe Shea, VP Nuclear Licensing Kevin Casey, Sr. Program Manager Tennessee River Operations Overview Kevin Casey, Sr. Program Manager Fukushima Response Project, Licensing SQN and WBN Hazard Reevaluation Report Task Schedule Update Kevin Casey TVA Dam Stability Analysis K
i C
TVA Dam Stability Analysis TVA Dam Screen Process PMF and Seismic Stability Analysis Seismic and Combined Events Evaluation Methodology Multiple Dam Failure Event Evaluation Methodology Kevin Casey Critical Path for SQN & WBN HRR Submittal TVA Review of Draft Dam Failure Interim Staff Guidance (ISG)
Kevin Casey Current Flood Protection Joe Shea Current Flood Protection Joe Shea Impact to Browns Ferry Nuclear Plant Joe Shea Impact to Watts Bar Nuclear Plant, Unit 2 Joe Shea 2
TVA Nuclear Power Group Impact to Watts Bar Nuclear Plant, Unit 2 Joe Shea Closing Remarks Joe Shea
Introduction Schedule Update Improve to March 2015 Review of Draft Interim Staff Guidance Stability of Guidance 3
TVA Nuclear Power Group
TVA River Operations and Dams Kevin Casey, Sr. Program Manager Fukushima Response Project, Licensing
TVA River Operations Managing the Rivers of the Tennessee Valley TVA is unique in its responsibility and ability to manage the Tennessee River and its major tributaries through a system of 49 major dam projects The Tennessee watershed is complex, draining over 40,000 square miles River Operations provides operational control of the reservoirs in the Tennessee River System in an integrated fashion, including:
Flood Control Water Quality Navigation Hydropower Q
y Water Supply Recreation TVA has been a leader in river forecasting for several decades The Tennessee River is a well-researched and understood river system 5
TVA Nuclear Power Group and understood river system Many river modeling systems in place today had origins based in part on consultation with TVA experts
TVA River Operations Potentially Critical TVA Dams APPALACHIA BLUE RIDGE CHATUGE CHEROKEE BOONE CHICKAMAUGA DOUGLAS FONTANA FORT LOUDOUN FORT PATRICK HENRY HIWASSEE MELTON HILL HENRY NOTTELY SOUTH HOLSTON TELLICO WATAUGA WATTS BAR NORRIS 6
TVA Nuclear Power Group
SQN and WBN HRR Status Kevin Casey, Sr. Program Manager Fukushima Response Project, Licensing
SQN and WBN HRR Status Main Task Status Update - March 2015 Task Start Finish Status 1a Main River Modeling Code Migration (SOCH to HEC-RAS)
May 2012 Nov 2012 Complete 1b Tributary River Modeling Code Migration (SOCH to HEC-RAS)
March 2013 Nov 2013 In-progress 2
Confirm critical storm PMP selection Dec 2012 Jan 2013 Complete 3
Perform local intense precipitation analysis for SQN/WBN Sept 2012 May 2013 In-progress 3
SQN/WBN Sept 2012 May 2013 In progress 4a Sunny Day Dam Failure - WBH - east embankment failure Jan 2013 Feb 2013 Complete 4b Sunny Day Dam Failure - Tributary Dams March 2013 Nov 2014 In progress 5
Perform PMF simulations - 2 storms - all dams stable Feb 2013 March 2013 In progress 5
Perform PMF simulations 2 storms all dams stable Feb 2013 March 2013 In progress 6
Evaluate Stability of 18 dams under PMF conditions Sept 2012 March 2014 In-progress 7
Perform PMF simulations using results of stability analysis April 2014 Dec 2014 Not Started 8
Develop dam specific seismic hazards Feb 2013 April 2013 In-progress 9
Evaluate seismic stability of 18 dams Sept 2012 March 2014 In-progress 10 Perform simulations using results of seismic stability analysis April 2014 Dec 2014 Not Started 8
TVA Nuclear Power Group 11 Perform simulations to quantify uncertainties June 2014 Dec 2014 Not Started 12 Prepare HRRs with results and interim actions, as required Jan 2015 March 2015 Not Started
TVA Dam Stability Analysis Kevin Casey, Sr. Program Manager Fukushima Response Project, Licensing
TVA Dam Stability Analysis TVA Dam Screening Process Flowchart 10 TVA Nuclear Power Group
TVA River Operations Potentially Critical TVA Dams with Structures IDd Dam Projects Types of Dam Features Embankments Concrete Spillways Intake Gates Other Features
- ofHydro Units Embankments Concrete Spillways IntakeGates OtherFeatures Units 1 Apalachia 0
1 10 1
Penstock, Lined&Unlined Tunnel,SurgeChannel 2
2 BlueRidge 1
0 8
2 Ungated spillway 1
3 Boone 1
1 5
6 Sluiceway 3
4 Chatuge 4
0 50 2
Penstock 1
5 Cherokee 4
1 9
4 8 Sluices 4
6 Chickamauga 2
1 18 6
1 Lock 4
7 Douglas 11 1
11 4
8 Sluices 4
8 Fontana 0
1 4
3 6-Sluices, Emergency Spillway 3
9 Fort Loudoun 2
1 14 6
1 Lock 4
9 FortLoudoun 2
1 14 6
1 Lock 4
10 FortPatrick Henry 0
1 5
4 None 2
11 Hiwassee 0
1 7
2 2-Penstock,4-LinedSluices 2
12 MeltonHill 0
1 3
3 1 Lock 2
13 Norris 1
1 3
2 2-Penstock,8 Sluices 2
14 Nottely 2
0 50 2
Steel Lined Tunnel 1
14 Nottely 2
0 50 2
SteelLinedTunnel 1
15 SouthHolston 2
0 1
1 PowerTunnel,Sluiceway, LinedTunnel,Emergency Spillway 1
16 Tellico 4
1 3
0 EmergencySpillway 0
PowerTunnel,Sluiceway, i
d l
11 TVA Nuclear Power Group 17 Watauga 1
0 1
1 LinedTunnel 2
18 WattsBar 3
1 20 6
1 Lock 5
TOTAL 38 13 222 52 58 43
TVA Dam Stability Analysis PMF and Seismic Stability Analysis Flowchart 12 TVA Nuclear Power Group
TVA Dam Stability Analysis PMF and Seismic Stability Analysis Flowchart (contd) 13 TVA Nuclear Power Group
TVA Dam Stability Analysis Detailed Field Investigation Status Flow Diagram Dam Projects Dam Structure Borings (Complete/Total)
Status j
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p
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Embankments Concrete 1 Apalachia 2/10 0/0 In-progress 2 Blue Ridge 0/0 0/0 Complete 3 Boone 15/15 0/0 Complete 4 Chatuge 51/51 0/0 Complete 4 Chatuge 51/51 0/0 Complete 5 Cherokee 42/42 0/0 Complete 6 Chickamauga 33/58 0/0 In-progress 7 Douglas 68/79 4/4 In-progress 8 Fontana 5/6 0/0 In-progress 9 Fort Loudon 48/58 13/13 In progress 14 TVA Nuclear Power Group 9 Fort Loudon 48/58 13/13 In-progress
TVA Dam Stability Analysis Detailed Field Investigation Status Flow Diagram Dam Projects Dam Structure Borings (Complete/Total)
Status j
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p
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Embankments Concrete 10 Fort Patrick Henry 3/6 0/0 In-progress 11 Hiwassee 0/4 4/26 In-progress 12 Melton Hill 0/9 0/0 Not Started 13 Norris 7/17 0/0 In-progress 13 Norris 7/17 0/0 In-progress 14 Nottely 26/49 0/0 In-progress 15 South Holston 40/40 0/0 Complete 16 Tellico 32/37 4/4 In-progress 17 Watauga 3/24 0/0 In-progress 18 Watts Bar 35/45 2/10 In-progress 15 TVA Nuclear Power Group p
g
TVA Dam Stability Analysis Seismic and Combined Events Evaluation Methodology TVA assumed the following in development of the SQN and WBN HRR proposed schedule:
D l
b bili ti i
i h d
l i (PSHA) 1 10 3 10 4 10 5 if Develop probabilistic seismic hazard analysis (PSHA) 1 x 10-3, 10-4, 10-5 uniform hazard response spectra for each potentially critical dam including deaggregation plots for use in multiple dam failure evaluations due to a single seismic event 2012 EPRI CEUS source model 2012 EPRI CEUS source model 2004/2006 EPRI attenuation model Site amplification using dam specific geologic profiles Perform combined events (seismic + flood) stability evaluations of dams 1 x 10-4 uniform hazard response spectra and 25 year flood inflows 1/2 of 1 x 10-4 uniform hazard response spectra and 500 year flood inflows Based on draft NEI white paper and several previous public meeting discussions 16 TVA Nuclear Power Group
TVA Dam Stability Analysis Multiple Dam Failure Event Evaluation Methodology TVA is developing evaluation methodologies to address multiple dam failure evaluations due to a single seismic event and will consider the draft ISG Utilizing outside resources through Jack R. Benjamin & Associates, Inc TVA will present details of its multiple dam failure methodology to the NRC on or before June 30, 2013 as stated in the SQN and WBN HRR extension request letter 17 TVA Nuclear Power Group
TVA Dam Stability Analysis Critical Path Tasks for SQN & WBN HRR Submittal March 2014 Complete 18 dam stability analyses October 2014 Perform PMF March 2015 Perform PMF Simulations (21,400 sq mi storm)
March 2015 Submit WBN HRR to NRC 2012 2013 2015 December 2014 Finalize Wind Wave Run-up Calc 2014 December 2014 Perform PMF Simulations (21,400 sq mi storm) w/ Downstream Dam June 2014 Develop PMF DRC for 18 Dams August 2014 March 2015 Submit SQN HRR to NRC w/ Downstream Dam Failures August 2014 Develop HEC-RAS Unsteady Flow Rules for PMF 18 TVA Nuclear Power Group
TVA Review of Draft ISG TVA Review of Draft ISG Kevin Casey, Sr. Program Manager Fukushima Response Project, Licensing
TVA Review of Draft ISG TVA has begun a thorough review of the draft ISG and has identified the following areas as impacting current analysis assumptions:
Use of USBR risk based analysis methods vs TVA dam stability deterministic methods Requirement for 10-6 annual exceedance probability of combined events (seismic + flood)
Detailed seismic analysis of spillways, gates, outlet works, and other appurtenances Consideration for potential impact from barges on navigable waterways At least one turbine should always be assumed to be down (e g for maintenance or other reasons) in At least one turbine should always be assumed to be down (e.g. for maintenance or other reasons) in performing flood routings.
TVA will continue to review the guidance and TVA will submit formal comments on the draft ISG as requested in the Federal Register Notice.
requested in the Federal Register Notice.
20 TVA Nuclear Power Group
TVA-Current Flood Protection TVA Current Flood Protection Joe Shea, VP Nuclear Licensing
TVA -Current Flood Protection Hydrology Actions Taken by TVA TVA has taken several actions to mitigate flood risk:
Comprehensive review and updating of TVA Hydrology modeling and calculations (Complete)
Fukushima Response
Conducted walkdowns to review impacted systems, structures and components and identify physical margins
Ran simulation to show feasibility of closing HESCO barrier openings (Complete)
Ran simulation to show feasibility of closing HESCO barrier openings (Complete)
Perform monthly inspections of HESCO flood barriers until permanent modification complete (Continuous)
Flood Mode preparation procedure improvements including reasonable simulation
Flood Mode preparation procedure improvements including reasonable simulation by December 31, 2013 (Scheduled)
Modifications to address flood mode operations
Diesel Generator barriers (SQN) (Complete)
Essential Raw Cooling Water (ERCW) barrier (SQN) (Complete) g
(
)
(
) (
p
)
Flood Mode Spool Piece Reduction (SQN and WBN) (In Design)
Intake Pumping Station (IPS) barrier (WBN) (In Design)
Thermal Barrier Booster Pump (TBBP) barrier (WBN) (Complete)
Main Control Room / Shutdown Board Room chiller barriers (WBN)
(Complete) 22 TVA Nuclear Power Group
Spent Fuel Pool Pumps and Skimmer pumps barrier (WBN) (Complete)
TVA has committed to complete permanent modifications to replace HESCO barriers at four dams upstream of SQN and WBN by October 2015
TVA -Current Flood Protection Hydrology Actions Taken by TVA (Contd) 23 TVA Nuclear Power Group
TVA -Current Flood Protection Coordination between NPG and River Operations River Operations ability to control river flows, reservoir storage levels, river temperatures and levels presents TVA with unique advantages to enhance and protect nuclear plant operations, including:
One vision and mission O
Owns river system operations and nuclear plants
Dam release coordination
Shared Responsibility for Nuclear and Dam Safety The River Forecast Center (RFC) staff utilizes forecasts of significant precipitation events, allowing for implementation of actions that can be taken to mitigate hydrothermal and flood challenges The RFC operates 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> a day, 365 days a year
Monitors 200+ rain gauges, 60+ stream flow gauges, reservoir headwater, tailwater and discharge at 49 dams
Reviews and revises river discharge schedule 2-4 times a day, and provides flood warning notification based on pre-determined conditions
Utilizes procedures that require NPG review of any changes and assumptions used to model river conditions to determine impact to site licensing basis (e.g., Intergroup Agreement: Nuclear Operations and River Operations; Coordination of Hydrology Issues)
NPG and RO&R procedures require early communication with sites to identify any potential flooding diti b
d di t d i it ti l
t d
l 24 TVA Nuclear Power Group conditions based on predicted precipitation volumes not measured volumes
TVA -Current Flood Protection History of Recorded Floods The TN valley has not experienced a flood in recorded history which has exceeded plant grade at either SQN and WBN.
740 739.2 728 WBN Flooding Elevations vs Site Grade 750 SQN Flooding Elevations vs Site Grade 680 690 700 710 720 730 728 717.2 716.3 701 698.2 697 684 681 680 690 700 710 720 730 740 722 705 701 690.5 688.5 687.8 687 682 676 670 680 670 680 It is TVAs position that the likelihood of such an event occurring 25 TVA Nuclear Power Group It is TVA s position that the likelihood of such an event occurring within the extension request timeframe is very low.
TVA-Impact to Browns Ferry Nuclear Plant TVA Impact to Browns Ferry Nuclear Plant Joe Shea, VP Nuclear Licensing
Impact to Browns Ferry Nuclear Plant
BFN identified as Priority 2 site, hazard reevaluation report due March 2014
In addition to the 18 dams impacting SQN and WBN, 4 additional dams required t
b l
d f BFN to be analyzed for BFN NICKAJACK GUNTERSVILLE TIMS FORD WHEELER
BFN HRR cannot be competed prior to completion of SQN/WBN HRR analysis work
BFN Recommendation 2.1 Project has started j
27 TVA Nuclear Power Group
TVA-Impacts to Watts Bar Nuclear Plant, Unit 2 TVA Impacts to Watts Bar Nuclear Plant, Unit 2 Joe Shea, VP Nuclear Licensing
Impact to Watts Bar Nuclear Plant, Unit 2 Watts Bar Unit 2 Licensing Basis
SECY-07-0096 established the considerations for WBN Units 1 and 2 having the same licensing basis licensing basis
The WBN Unit 1 licensing basis, as modified by the License Amendment Request currently under review by the Staff is appropriate for Unit 2
Fukushima Orders for FLEX and Spent Fuel Pool Instrumentation will be implemented
WBN 2 will follow the WBN Unit 1 lead in the Flood Hazard Reevaluation and Actions
WBN 2 will propose a license condition to track the Flood Hazard Reevaluation commitments
WBN2 ill i l
t th I
d Fl d Miti ti C
biliti di d i TVA
WBN2 will implement the Improved Flood Mitigation Capabilities discussed in TVAs April 16, 2013, letter to NRC TVA considers the current licensing approach to external flood hazards as described in g
pp the WBN Unit 2 FSAR as supplemented by the improvements described in TVAs letter dated June 13, 2012, as providing sufficient basis for supporting a finding that the licensing basis will provide adequate protection against design basis external floods.
29 TVA Nuclear Power Group
Cl i
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Closing Remarks Joe Shea, Vice President, Nuclear Licensing