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MONTHYEARML11157A0422009-11-0202 November 2009 Enclosure 2, Calculation RSOFLHROGCDX00033320090003, PMF Temporary Modification Analysis. Project stage: Other ML1016504272010-06-14014 June 2010 E-mail - R. Martin to J. Stringfellow Regarding Acceptance of Application Dated May 12, 2010 Project stage: Acceptance Review ML1022104402010-08-0606 August 2010 Final Safety Analysis Report (FSAR) - Response to Requests for Additional Information Project stage: Response to RAI ML1028003472010-10-0404 October 2010 Final Safety Analysis Report (FSAR) - Response to Requests for Additional Information Project stage: Response to RAI ML11154A1412011-04-14014 April 2011 Enclosure 3, Calculation RSOGENROGCDX00033320110002, Seismic Evaluation of Hesco Baskets. Project stage: Other ML11112A1372011-04-20020 April 2011 Response to Request for Additional Information Regarding Final Safety Analysis Report Section 2.4 Project stage: Response to RAI ML11154A1392011-06-0101 June 2011 Information Presented in the May 11-12, 2011 Tva/Nrc Meeting Regarding Final Safety Analysis Report Section 2.4 Project stage: Meeting ML11154A1402011-06-0101 June 2011 Enclosure 1, 05/11/2011 Presentation Package Temporary Dams' Modification Project. Project stage: Other ML11306A1932011-10-31031 October 2011 Results of the Hydrology Analysis Without Use of Sand Baskets Project stage: Other ML12255A2002012-09-0606 September 2012 Long-Term Stability Analysis Methodology Project stage: Other 2011-10-31
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Category:Letter
MONTHYEARML23319A2452024-01-29029 January 2024 Issuance of Amendment Nos. 366 and 360; 164 and 71 Regarding the Adoption of TSTF-567, Revision 1, Add Containment Sump TS to Address GSI-191 Issues ML24008A2462024-01-18018 January 2024 Revision to the Reactor Vessel Material Surveillance Capsule Withdrawal Schedule CNL-24-017, Tennessee Valley Authority - Central Emergency Control Center Emergency Plan Implementing Procedure and Emergency Preparedness Department Procedure Revisions2024-01-17017 January 2024 Tennessee Valley Authority - Central Emergency Control Center Emergency Plan Implementing Procedure and Emergency Preparedness Department Procedure Revisions CNL-24-016, Supplement to Application to Modify the Technical Specification Surveillance Requirement 3.9.5.1 (WBN-TS-21-14)2024-01-10010 January 2024 Supplement to Application to Modify the Technical Specification Surveillance Requirement 3.9.5.1 (WBN-TS-21-14) CNL-23-052, Application to Adopt TSTF-427-A, Revision 2, Allowance for Non-Technical Specification Barrier Degradation on Supported System Operability2024-01-0909 January 2024 Application to Adopt TSTF-427-A, Revision 2, Allowance for Non-Technical Specification Barrier Degradation on Supported System Operability CNL-23-062, Application to Revise the Technical Specifications Section 3.8.2, AC Sources-Shutdown, to Remove Reference to the C-S Diesel Generator (WBN-TS-23-018)2024-01-0808 January 2024 Application to Revise the Technical Specifications Section 3.8.2, AC Sources-Shutdown, to Remove Reference to the C-S Diesel Generator (WBN-TS-23-018) ML23346A1382024-01-0303 January 2024 Regulatory Audit Summary Related to Request to Increase the Number of Tritium Producing Burnable Absorber Rods CNL-23-069, Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation2023-12-21021 December 2023 Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation IR 05000390/20234412023-12-21021 December 2023 Plantfinal Significance Determination for a Security-Related Greater than Green Finding, Nov, and Assessment Follow-up, 05000390-2023441 and 05000391-2023441-Public CNL-23-036, Application to Revise Function 5 of Technical Specification Table 3.3.2-1, Engineered Safety Feature Actuation System Instrumentation, for the Sequoyah Nuclear Plant and Watts Bar Nuclear Plant (SQN-TS-23-02 and WBN-TS-23-08)2023-12-18018 December 2023 Application to Revise Function 5 of Technical Specification Table 3.3.2-1, Engineered Safety Feature Actuation System Instrumentation, for the Sequoyah Nuclear Plant and Watts Bar Nuclear Plant (SQN-TS-23-02 and WBN-TS-23-08) IR 05000390/20234042023-12-14014 December 2023 Security Baseline Inspection Report 05000390/2023404 and 05000391/2023404 CNL-23-001, Rebaseline of Sections 3.1 and 3.2 of the Technical Specifications (WBN-TS-23-01)2023-12-13013 December 2023 Rebaseline of Sections 3.1 and 3.2 of the Technical Specifications (WBN-TS-23-01) ML23293A0572023-12-0606 December 2023 Issuance of Amendment Nos. 163 and 70 Regarding Adoption of TSTF-501-A, Revision 1, Relocate Stored Fuel Oil and Lube Oil Volume Values to Licensee Control IR 05000390/20230102023-11-30030 November 2023 RE-Issue Watts Bar Nuclear Plant - Biennial Problem Identification and Resolution Inspection Report 050000390/2023010 and 05000391/2023010 and Apparent Violation CNL-23-067, Central Emergency Control Center Emergency Plan Implementing Procedure Revisions2023-11-27027 November 2023 Central Emergency Control Center Emergency Plan Implementing Procedure Revisions IR 05000390/20230032023-11-13013 November 2023 Integrated Inspection Report 05000390/2023003 and 05000391/2023003 and Apparent Violation ML23312A1432023-11-0808 November 2023 Submittal of Dual Unit Updated Final Safety Analysis Report (UFSAR) Amendment 5 CNL-23-059, Supplement to Sequoyah Nuclear Plant, Units 1 and 2, and Watts Bar Nuclear Plant, Units 1 and 2, Application to Revise Technical Specifications to Adopt TSTF-567-A, Revision 1, Add Containment Sump TS to Address GSI-191 Issues (SQN-TS-23-2023-09-20020 September 2023 Supplement to Sequoyah Nuclear Plant, Units 1 and 2, and Watts Bar Nuclear Plant, Units 1 and 2, Application to Revise Technical Specifications to Adopt TSTF-567-A, Revision 1, Add Containment Sump TS to Address GSI-191 Issues (SQN-TS-23-03 CNL-23-061, Tennessee Valley Authority - Central Emergency Control Center Emergency Plan Implementing Procedure Revision2023-09-20020 September 2023 Tennessee Valley Authority - Central Emergency Control Center Emergency Plan Implementing Procedure Revision ML23251A2002023-09-11011 September 2023 Request for Withholding Information from Public Disclosure for Watts Bar Nuclear Plant, Units 1 and 2 CNL-23-057, Central Emergency Control Center Emergency Plan Implementing Procedure Revisions. Includes CECC-EPIP-1, Revision 76 and CECC-EPIP-9, Revision 642023-09-0505 September 2023 Central Emergency Control Center Emergency Plan Implementing Procedure Revisions. Includes CECC-EPIP-1, Revision 76 and CECC-EPIP-9, Revision 64 IR 05000390/20230052023-08-30030 August 2023 Updated Inspection Plan for Watts Bar Nuclear Plant, Units 1 and 2 - Report 05000390/2023005 and 05000391/2023005 ML23233A0042023-08-28028 August 2023 Proposed Alternative to the Requirements of the ASME Boiler and Pressure Vessel Code for Upper Head Injection Dissimilar Metal Butt Welds IR 05000390/20230022023-08-16016 August 2023 Reissue - Watts Bar Nuclear Plant - Integrated Inspection Report 05000390/2023002 and 05000391/2023002 ML23220A1582023-08-0909 August 2023 Integrated Inspection Report 05000390/2023002 and 05000391/2023002 CNL-23-045, License Amendment Request to Revise Technical Specification Table 1.1-1 Regarding the Required Number of Fully Tensioned Reactor Pressure Vessel Head Closure Bolts (WBN-TS-23-010)2023-08-0707 August 2023 License Amendment Request to Revise Technical Specification Table 1.1-1 Regarding the Required Number of Fully Tensioned Reactor Pressure Vessel Head Closure Bolts (WBN-TS-23-010) CNL-23-028, Application to Revise Technical Specifications to Adopt TSTF-567-A, Revision 1, Add Containment Sump TS to Address GSI-191 Issues (SQN-TS-23-03 and WBN-TS-23-06)2023-08-0202 August 2023 Application to Revise Technical Specifications to Adopt TSTF-567-A, Revision 1, Add Containment Sump TS to Address GSI-191 Issues (SQN-TS-23-03 and WBN-TS-23-06) ML23192A4472023-07-31031 July 2023 Staff Assessment of Updated Seismic Hazards at TVA Sites Following the NRC Process for the Ongoing Assessment of Natural Hazards Information CNL-23-055, Tennessee Valley Authority - Emergency Preparedness Department Procedure Revision. Includes EPDP-3, Revision 3, Emergency Plan Exercises and Preparedness Drills2023-07-25025 July 2023 Tennessee Valley Authority - Emergency Preparedness Department Procedure Revision. Includes EPDP-3, Revision 3, Emergency Plan Exercises and Preparedness Drills IR 05000390/20230112023-07-24024 July 2023 Quadrennial Focused Engineering Inspection (FEI) Commercial Grade Dedication Report 05000390 2023011 and 05000391 2023011 CNL-23-053, Tennessee Valley Authority - Radiological Emergency Plan Revisions2023-07-18018 July 2023 Tennessee Valley Authority - Radiological Emergency Plan Revisions CNL-23-020, Application to Revise Technical Specifications to Adopt TSTF-501-A, Revision 1, Relocate Stored Fuel Oil and Lube Oil Volume Values to Licensee Control (WBN-TS-22-06)2023-06-28028 June 2023 Application to Revise Technical Specifications to Adopt TSTF-501-A, Revision 1, Relocate Stored Fuel Oil and Lube Oil Volume Values to Licensee Control (WBN-TS-22-06) CNL-23-049, Tennessee Valley Authority - Radiological Emergency Plan and Central Emergency Control Center Emergency Plan .2023-06-26026 June 2023 Tennessee Valley Authority - Radiological Emergency Plan and Central Emergency Control Center Emergency Plan . ML23122A2322023-06-0707 June 2023 Issuance of Amendment Nos. 162 and 69 Regarding Change to Date in Footnotes for Technical Specification 3.7.11, Control Room Emergency Air Temperature Control System (Creatcs) CNL-23-044, Transmittal of Revision 3 to WCAP-18774-P and WCAP-18774-NP, Addendum to the Rotterdam Dockyard Company Final Stress Report for 173 P.W.R. Vessels TVA III & IV (Report No. 30749-B-030, Rev. 3) - Evaluation of One Closure Stud Out2023-06-0101 June 2023 Transmittal of Revision 3 to WCAP-18774-P and WCAP-18774-NP, Addendum to the Rotterdam Dockyard Company Final Stress Report for 173 P.W.R. Vessels TVA III & IV (Report No. 30749-B-030, Rev. 3) - Evaluation of One Closure Stud Out IR 05000390/20234032023-05-30030 May 2023 Cyber Security Inspection Report 05000390/2023403 and 05000391/2023403 ML23131A1812023-05-23023 May 2023 Correction to Amendment No. 161 to Facility Operating License No. NPF-90 CNL-23-042, Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions2023-05-16016 May 2023 Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions IR 05000390/20220032023-05-0909 May 2023 Reissue Watts Bar Nuclear Plant - Integrated Inspection Report 05000390/2022003 and 05000391/2022003 ML23125A2202023-05-0505 May 2023 Issuance of Amendment No. 161 Regarding a Change to Footnotes for Technical Specification Table 1.1-1 Modes (Emergency Circumstances) IR 05000390/20230012023-05-0404 May 2023 Integrated Inspection Report 05000390/2023001 and 05000391/2023001 CNL-23-043, Emergency License Amendment Request to Relax the Required Number of Fully Tensioned Reactor Pressure Vessel Head Closure Studs in Technical Specification Table 1.1-1, Modes (WBN-TS-23-09)2023-05-0404 May 2023 Emergency License Amendment Request to Relax the Required Number of Fully Tensioned Reactor Pressure Vessel Head Closure Studs in Technical Specification Table 1.1-1, Modes (WBN-TS-23-09) CNL-23-032, Clinch River, Sequoyah, Units 1 and 2, Watts Bar, Unit 1 and 2, Nuclear Quality Assurance Plan, TVA-NQA-PLN89-A, Revision 412023-04-27027 April 2023 Clinch River, Sequoyah, Units 1 and 2, Watts Bar, Unit 1 and 2, Nuclear Quality Assurance Plan, TVA-NQA-PLN89-A, Revision 41 CNL-23-030, Tennessee Valley Authority - Hydrologic Engineering Center River Analysis System Project Milestone Status Update2023-04-27027 April 2023 Tennessee Valley Authority - Hydrologic Engineering Center River Analysis System Project Milestone Status Update CNL-23-033, Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revision2023-04-24024 April 2023 Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revision CNL-23-029, Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions2023-04-11011 April 2023 Radiological Emergency Plan and Central Emergency Control Center Emergency Plan Implementing Procedure Revisions ML23072A0652023-04-0505 April 2023 Units 1 and 2 Issuance of Amendment Nos. 364 and 358; 160 and 68 Regarding a Revision to Technical Specification 3.4.12 ML23073A2762023-04-0303 April 2023 Individual Notice of Consideration of Issuance of Amendments to Facility Operating Licenses, Proposed No Significant Hazards Consideration Determination, and Opportunity for a Hearing (EPID L-2023-LLA-0029) (Letter) CNL-23-023, Annual Insurance Status Report2023-03-30030 March 2023 Annual Insurance Status Report CNL-23-024, TVA Guarantee of Payment of Deferred Premiums - 2022 Annual Report2023-03-29029 March 2023 TVA Guarantee of Payment of Deferred Premiums - 2022 Annual Report 2024-01-09
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Tennessee Valley Authority, Post Office Box 2000, Spring City, Tennessee 37381-2000 September 6, 2012 10 CFR 50.36 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001 Watts Bar Nuclear Plant, Unit 2 NRC Docket No. 50-391
Subject:
Watts Bar Nuclear Plant (WBN) Unit 2 - Long-Term Stability Analysis Methodology
Reference:
- 1. TVA Letter to NRC dated April 20, 2011, "Response to Request for Additional Information Regarding Final Safety Analysis Report Section 2.4 (TAC NO. ME3945)"
The purpose of this submittal is to provide information to satisfy the following commitment previously made in Reference 1. The previous commitment verbiage is as follows:
"TVA will provide an update of the WBN Unit 2 FSAR to describe the long-term stability analysis methodology following the completion of the finite element analyses. .. " provides a summary of the long-term stability analysis methodology. provides the list of regulatory commitments contained within this letter.
U.S. Nuclear Regulatory Commission Page 2 September 6, 2012 I declare under penalty of perjury that the foregoing is true and correct. Executed on the 6 th day of September, 2012.
Respectfully, Raymond A. Hruby, Jr.
General Manager, Technical Services Watts Bar Unit 2
Enclosure:
- 1. Summary of the Long-Term Stability Analysis Methodology
- 2. New Regulatory Commitment cc (Enclosures):
U. S. Nuclear Regulatory Commission Region II Marquis One Tower 245 Peachtree Center Ave., NE Suite 1200 Atlanta, Georgia 30303-1257 NRC Resident Inspector Unit 2 Watts Bar Nuclear Plant 1260 Nuclear Plant Road Spring City, Tennessee 37381
Enclosure 1 Summary of the Long-Term Stability Analysis Methodology Summary In 2009, the Probable Maximum Flood (PMF) analysis for the Watts Bar Nuclear Plant (WBN) site was revised to address a number of issues, including non-conservative assumptions. The revised PMF analysis resulted in a higher PMF level for the WBN site.
This prompted a re-evaluation of stability for dams upstream of WBN.
Both Cherokee and Douglas Dams were re-evaluated with higher PMF levels using the current nuclear design and licensing basis criteria and satisfactorily meet those criteria.
However, a simplified, conservative re-evaluation to present day industry standard criteria resulted in a lower than allowable factor of safety for sliding and overturning for the concrete portions of Cherokee Dam which prompted a more refined finite element analysis. Present day industry standard criteria specify a cracked base analysis methodology that was not used in nuclear design and licensing basis calculation nor had not been used historically in the evaluations of TVA dams. The cracked base analysis is implemented if tension exists in the base of the dam. Then cracking in the foundation is assumed resulting in increased uplift pressure in the cracks forming at the base of the dam. Douglas Dam is included in the extent of condition because it is of similar design to Cherokee Dam.
Recently completed finite element analyses for both Cherokee and Douglas Dams utilizing current industry standards (Ref. 1) indicate the potential for failure of portions of the dams in extreme flood events. As a result, Cherokee and Douglas Dams will require modifications to ensure that the dams meet the current industry stability criteria. While the finite element analyses are informative, and TVA will be prudently taking action to upgrade the dam, these analyses do not invalidate the nuclear design basis analysis of record.
The analyses which determine the design basis flood or PMF elevations for WBN credit the stability of Cherokee and Douglas Dams for PMF headwater and tailwater loading conditions.
Section 2.4.3.4 of the Watts Bar Nuclear Plant UFSAR states:
"For concrete dam sections, comparisons were made between the original design headwater and tailwater levels and those that would prevail in the PMF. If the overturning moments and horizontal forces were not increased by more than about 20%, the structures were considered safe against failure. All upstream dams passed this test except Douglas, Fort Loudoun, and Watts Bar. Original designs showed the spillway sections of these dams to be most vulnerable. These spillway sections were examined in further detail and judged to be stable."
The critical headwater elevation for Cherokee Dam and Douglas Dam at which the factor of safety for some blocks is not satisfactory is 1,085 ft and 1,015 ft. respectively. The probabilities of reaching these critical headwater elevations are small. During studies completed in 2004, a total of 140 hypothetical design storms were analyzed at Cherokee and Douglas Dams. None of these design storms, including some with estimated E1-1
Enclosure I Summary of the Long-Term Stability Analysis Methodology recurrence intervals in excess of 10,000 years, produced headwater elevations greater than 1,075 ft. and 1,002.3 ft. respectively, well below the critical headwater elevations.
Therefore, it can be judged that the probabilities of exceeding the critical headwater elevations are significantly smaller than lx1 0-4.
TVA is committed to prudently pursuing a dam safety improvement project as described below. The modifications for Cherokee and Douglas Dams will be designed and implemented prior to WBN Unit 2 startup.
Extent of Condition Review In 2010, TVA developed the Dam Safety Governance organization in an effort not related to the Cherokee/Douglas issue or the PMF analysis update. Through efforts of this organization, TVA has recently adopted the Federal Energy Regulatory Commission (FERC) and other State and Federal dam safety provisions as the basis for the design and evaluation of TVA dams as specified in TVA-SPP-27. 1. TVA's River Operations' Non Power Assets program has initiated a multi-year dam safety improvement program which will systematically evaluate all the dams using criteria which incorporates current industry standards/practices. As these dams are found to require modifications, the findings will be prioritized and remediated as appropriate.
Conclusion Cherokee and Douglas Dams have been evaluated to the licensing and design basis for updated PMF elevations which found the dams to be stable. In addition, the Cherokee and Douglas Dams were also evaluated using the analysis of record with more limiting assumptions of no cohesion, uplift pressure without drain efficiency, and tailwater reduction for the spillway sections; and the dams were found stable. However, an analysis, using current industry criteria, indicates stability concerns with Cherokee and Douglas Dams.
Cherokee Dam and Douglas Dam finite element analyses have been completed (References 2 and 3) which refine the area of the dam which is susceptible to potential instability during PMF loading. These references are available for NRC review. TVA is committed to prudently pursuing a dam safety improvement project. The modifications for Cherokee and Douglas Dams will be designed and implemented prior to WBN Unit 2 startup.
References
- 1. "Stability Analysis of Concrete Structures," EM 1110-2-2100, U.S. Army Corps of Engineers, December 2005.
- 2. "Cherokee Dam - Stress and Stability Analysis of the Concrete Sections Using 3D Finite Element Analysis - 100% Submittal," Calculation RSOCRHROGCDX000326201 10001 Revision 1, dated May 9, 2012.
- 3. "Douglas Dam - Stress and Stability Analysis of the Concrete Sections Using 3D Finite Element Analysis - 100% Submittal," Calculation RSODGHROGCDX000326201 10001 Revision 1, dated August 30, 2012.
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ENCLOSURE 2 New Regulatory Commitment TVA is committed to prudently pursuing a dam safety improvement project. The modifications for Cherokee and Douglas Dams will be designed and implemented prior to WBN Unit 2 startup.
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