ML13276A050
| ML13276A050 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar, Sequoyah  |
| Issue date: | 09/30/2013 |
| From: | James Shea Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML13276A050 (10) | |
Text
Tennessee Valley Authority, 1101 Market Street, Chattanooga, Tennessee 37402 September 30, 2013 10 CFR 50.54(f)
ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Sequoyah Nuclear Plant, Units 1 and 2 Facility Operating Licenses Nos. DPR-77 and DPR-79 NRC Docket Nos. 50-327 and 50-328 Watts Bar Nuclear Plant, Unit 1 Facility Operating License No. NPF-90 NRC Docket No. 50-390 Watts Bar Nuclear Plant, Unit 2 Construction Permit No. CPPR-92 NRC Docket No. 50-391
Subject:
Second Quarterly Status Report to the Flooding Hazard Reevaluation Report Extension Request and Response to the Request for Additional Information Related to the Review of Potential Breaches of HESCO Flood Barriers and Earthen Embankments Affecting the Updated Hydro Analysis Results
References:
- 1. Letter from TVA to NRC, "Tennessee Valley Authority (TVA) - Extension Request Regarding the Flooding Hazard Reevaluation Report Required by NRC Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Recommendation 2.1, Flooding, of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident," dated March 12, 2013 (ML13080A073)
- 2. Letter from TVA to NRC, "Revised Commitments for the Extension Request Regarding the Flooding Hazard Reevaluation Report Required by NRC Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Recommendation 2.1, Flooding, of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident," dated May 9, 2013 (ML13133A004)
Printed on recycled paper I W (,-
U.S. Nuclear Regulatory Commission Page 2 September 30, 2013
- 3. Letter from NRC to TVA, "Sequoyah Nuclear Plant, Units 1 and 2, and Watts Bar Nuclear Plant, Units 1 and 2 - Relaxation of Response Due Dates Regarding Flooding Hazard Reevaluations for Recommendation 2.1 of the Near-Term Task Force Review of the Insights from the Fukushima Dai-ichi Accident," dated July 1, 2013 (ML13163A296)
- 4. Letter from TVA to NRC, "First Quarterly Status Report to the Flooding Hazard Reevaluation Report Extension Request Including Technical Pager Regarding Methodology for Multiple Dam Failures Due to Seismic Events," dated July 19, 2013 (ML13206A003)
- 5. Electronic Mail from NRC to TVA, "SQN 1 & 2 and WBN RAIs on TVA's Letter Dated January 18, 2013 (ML13025A262) - HESCO Flood Barriers and Earthen Embankments," dated July 23, 2013 (ML13205A165)
- 6. JLD-ISG-2013-01, "Guidance for Assessment of Flooding Hazards Due to Dam Failure," Revision 0 (ML13151A153)
- 7. Electronic Mail from TVA to NRC, "Quarterly Update/HESCO analysis RAI's," dated September 18, 2013 By letter dated March 12, 2013, the Tennessee Valley Authority (TVA) requested an extension to the schedule for submitting the Flooding Hazard Reevaluation Reports (HRRs) for the Sequoyah Nuclear Power Plant (SQN), Units 1 and 2, and the Watts Bar Nuclear Plant (WBN), Units 1 and 2 (Reference 1). After meeting with the Nuclear Regulatory Commission (NRC) on April 29, 2013, TVA committed in a follow-up letter dated May 9, 2013, to provide the SQN and WBN Flooding HRRs to the NRC by March 12, 2015 (Reference 2). The NRC approved the extension request in a July 1, 2013, letter to TVA (Reference 3).
TVA also committed in Reference 2 to provide periodic quarterly status reports of completed actions and progress to completing the HRRs to the SQN and WBN NRC Project Managers starting in June, 2013. TVA provided the first quarterly update in a meeting with the NRC on June 27, 2013, and submitted the written update on July 19, 2013 (Reference 4).
The purpose of this letter is to submit the second quarterly status report regarding the status of completed actions and progress to completing the HRRs. Progress continues on track to complete the HRRs as scheduled to meet the requested March 12, 2015, completion date. of this letter provides details to the status of tasks required for completion of the HRRs.
U.S. Nuclear Regulatory Commission Page 3 September 30, 2013 TVA will provide the third quarterly update regarding the status of completed actions and progress to completing the SQN and WBN HRRs by December 31, 2013, consistent with Commitment I in the Enclosure of IVA's letter to NRC dated May 9, 2013.
This letter also addresses the Request for Additional Information (RAI) related to the review of potential breaches of HESCO flood barriers and earthen embankments affecting the updated hydro analysis results. These RAls were received by electronic mail (email) on July 23, 2013 (Reference 5). A response was requested by August 31, 2013. Development of the HRRs will use Interim Staff Guidance (ISG) JLD-ISG-201 3-01, "Guidance for Assessment of Flooding Hazards Due to Dam Failure,n (Reference 6). Section 7 of the ISG provides specific guidance for analysis of hydrologic failure modes, including consideration of barge impacts. Because consideration of barge impacts will be addressed as indicated in the ISG, TVA confirmed via email (Reference 7) that the RAI response would be addressed when this evaluation is completed. provides the commitment by TVA to address the RAI related to the review of the potential breaches of HESCO flood barriers and earthen embankments affecting the updated hydro analysis results with the HRR. The due date for the HRR is March 12, 2015.
If you have questions regarding this matter, please contact Kevin Casey at (423) 751-8523.
Res~lly, J. lý. Ahea Vice President, Nuclear Licensing
Enclosures:
- 1. 2nd Quarterly Update for NTTF Recommendation 2.1, Flooding Hazard Reevaluation Report (HRR) Extension Request, September 30, 2013
- 2. List of Commitments cc (w/Enclosures):
NRC Regional Administrator - Region II NRR Director - NRC Headquarters NRC Senior Resident Inspector - Sequoyah Nuclear Plant NRC Senior Resident Inspector - Watts Bar Nuclear Plant NRR Project Manager - Sequoyah Nuclear Plant NRR Project Manager - Watts Bar Nuclear Plant, Unit I NRR Project Manager - Watts Bar Nuclear Plant, Unit 2
ENCLOSURE 1 2nd QUARTERLY UPDATE FOR NTTF RECOMMENDATION 2.1, FLOODING HAZARD REEVALUATION REPORT (HRR) EXTENSION REQUEST, SEPTEMBER 30, 2013
ENCLOSURE This update provides the status of the main tasks for completing the Flooding Hazard Reevaluation Reports (HRRs) outlined in the 1st quarterly update (Reference 3 of the cover letter). These main tasks are listed in Table 1 of this enclosure. As noted in the scheduled finish column, none of the tasks were scheduled to complete this quarter, July 1, 2013 to September 30, 2013. Tasks 1b, Tributary River Modeling Code Migration, 4b, Sunny Day Dam Failure - Tributary Dams, 6, Evaluate Stability of 18 dams under Probable Maximum Flood (PMF) conditions, and 9, Evaluate seismic stability of 18 dams, are in progress and are currently on track to finish as indicated in Table 1.
As presented in the 1st quarterly update, sub-tasks to Task 6 and Task 9 were outlined in Flowcharts 1 and 2. Completion of these sub-tasks also continues as indicated in Table 2 of this enclosure. As noted in Table 2, Field Investigations (Borings) have been completed for all 18 dams. Laboratory Testing was completed for the Chickamauga, Douglas, Fontana, Fort Loudoun, Fort Patrick Henry, Hiwassee, Nottely, and Watts Bar dams during this quarter.
Completion of the Laboratory Testing for the Appalachia, Melton Hill, Norris, and Watauga dams has been revised as indicated in Table 2. These revised dates do not impact the overall scheduled completion of the PMF and Seismic Stability Analysis tasks.
In the 1st quarterly update, TVA provided a technical paper regarding a methodology for evaluating multiple dam failures due to seismic events (Enclosure 2 of Reference 3 of the cover letter). TVA will utilize this methodology for evaluation of multiple dam failures due to a single seismic event in lieu of the methodology presented in Section 5.5 of the interim staff guidance, JLD-ISG-2013-01, "Guidance for Assessment of Flooding Hazards Due to Dam Failure.". This methodology has been incorporated in the overall task schedule as a sub-task to Task 9.
Progress on the status of this methodology will be reported in the 3rd quarterly update consistent with Commitment 1 in the Enclosure of TVA's letter to NRC dated May 9, 2013.
Overall, progress continues to complete the HRRs as scheduled to meet the requested March 12, 2015, completion date.
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TABLE I MAIN TASK STATUS UPDATE - SEPTEMBER 2013 TAKS-- FNS SAU Main River Modeling Code Migration la (SOCH to HEC-RAS) May 2012 Nov 2012 Complete 2 Confirm critical storm PMP selection Dec 2012 Jan 2013 Comnlete Aqiinnv flzav fl~m Pnihi ir - WRI-I -anct mhnnkmanf fniII ira 5 Perform PMF simulations - 2 storms - all dams stable 7 Perform PMF simulations usir 11 Perform simulations to auantifv uncertainties June 2014 Dec 2014 Not Started E1-2 of 5
FLOWCHART I PMF AND SEISMIC STABILITY ANALYSIS FLOWCHART (Note - Blocks 1 - 5 are sub-tasks to Tasks 6 & 9 on next page)
(Note - See Table 2 for status of blocks 2 - 4 for each individual dam)
Gahe avial dam.
spcii dat n6 Determine Analysis/
Acceptance Criteria based on TVA dam safety criteria Pefr fiel in etg to of0 4
-7a=strcue Model Dam Structures GT Strudl/ANSYS - Concrete GeoStudio - Earthen Embankments 5
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FLOWCHART 2 PMF AND SEISMIC STABILITY ANALYSIS FLOWCHART Develop Dam Specific Seismic Hazards (Task 8) 6 Perform Stability Analyses (PMF & Seismic) kr (Tasks 6 & 9) 7 Compare ReSUItS to Acceptance Criteria 8 Yes L
I No Yes I No 7, 7.T 77 "W"T,,
-.I"7711P.,t Stability Analysis Complete E1-4 of 5
TABLE 2 PMF AND SESIMIC STABILITY ANALYSIS STATUS BY DAM (updates as of 09/20/2013 noted in bold text)
Field Investigation Laboratory Develop Dam PMF and Seismic Stability Dam (Borings) Testing Specific Analysis Pr((#
complete/total # borings tC - estimate Hazards (scheduled completion)
Project (#cmlt/oa oig)to completion)
Block 2 Block 3 Block 4 Block 7 1 Appalachia Complete 10/10 ETC 09/30/14 Complete 03/31/14 2 Blue Ridge Complete - 0/0 N/A Complete 03/31/14 3 Boone Complete - 15/15 Complete Complete 03/31/14 4 Chatuge Complete - 51/51 Complete Complete 03/31/14 5 Cherokee Complete - 41/41 Complete Complete 03/31/14 6 Chickamauga Complete 52/52 Complete Complete 03/31/14 7 Douglas Complete - 75/75 Complete Complete 03/31/14 8 Fontana Complete - 6/6 Complete Complete 03/31/14 9 Fort Loudoun Complete - 57/57 Complete Complete 03/31/14 10 Fort Patrick Henry Complete - 6/6 Complete Complete 03/31/14 11 Hiwassee Complete - 4/4 Complete Complete 03/31/14 12 Melton Hill Complete - 717 ETC 10/31114 Complete 03/31/14 13 Norris Complete - 20/20 ETC 10/15/14 Complete 03/31/14 14 Nottely Complete - 48/48 Complete Complete 03/31/14 15 South Holston Complete - 40/40 Complete Complete 03/31/14 16 Tellico Complete - 53/53 Complete Complete 03/31/14 17 Watauga Complete - 24/24 ETC 10/11/14 Complete 03/31/14 18 Watts Bar Complete - 60/60 Complete Complete 03/31/14 E1-5 of 5
ENCLOSURE2 LIST OF COMMITMENTS
- 1. TVA to address the RAI related to the review of the potential breaches of HESCO flood barriers and earthen embankments affecting the updated hydro analysis results with the Hazard Reevaluation Report. The due date for the HRR is March 12, 2015.
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