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| | number = ML111110513 | | | number = ML111110513 |
| | issue date = 04/21/2011 | | | issue date = 04/21/2011 |
| | title = Watts Bar, Unit 2, Withdrawal of a Previous Comment | | | title = Withdrawal of a Previous Comment |
| | author name = Stinson D | | | author name = Stinson D |
| | author affiliation = Tennessee Valley Authority | | | author affiliation = Tennessee Valley Authority |
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| =Text= | | =Text= |
| {{#Wiki_filter:}} | | {{#Wiki_filter:Tennessee Valley Authority, Post Office Box 2000, Spring City, Tennessee 37381-2000 April 21, 2011 10 CFR 50.34 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 - WITHDRAWAL OF A PREVIOUS COMMITMENT |
| | |
| | ==Reference:== |
| | TVA letter dated June 28, 2010, Watts Bar Nuclear Plant (WBN) Unit 2 - |
| | Request for Additional Information (RAI) Regarding Licensees Final Safety Analysis Report Amendment Related to Section 4.2.2, Reactor Vessel Internal Components (TAC No. ME2731) |
| | The purpose of this letter is to withdraw a previous commitment made in the referenced letter. |
| | In that letter, TVA committed to replace prior to Unit 2 operation the current Unit 2 clevis insert bolts to a design which uses X-750 alloy with a high temperature heat (HTH) treatment, rolled threads, and a larger radius on the undercut of the cap screw head. Upon further evaluation, TVA has determined that this replacement is unwarranted at this time. |
| | The justification for this withdrawal stems from the fact that the bolting failure phenomenon has only known to have occurred at one unit in the industry. The phenomenon appears to be time based, and the breakage only occurs after many operating cycles. In discussions with personnel at the affected plant, TVA has learned that the cause is not yet known and that any change might be at best neutral to solving the problem. TVA has also confirmed via these discussions that bolting at the affected plants other unit does not have the same issue. In addition, WBN Unit 1 has operated with the same type bolting since 1995 with no failure of these bolts. |
| | The initial NRC RAI cited the Staff Requirements Memorandum dated July 25, 2007 (ADAMS Accession No. ML093370274) directing TVA to look for opportunities to resolve issues where the unirradiated state of WBN Unit Bar 2 makes the issue easier to resolve. At this time, the root cause of the subject issue has not been determined, an industry resolution has not been established, the problem appears to be restricted to a single unit at another utility, and WBN |
| | |
| | U.S. Nuclear Regulatory Commission Page 2 April 21, 2011 Unit 1 has operated with the X-750 bolting approximately sixteen years with no failure of these bolts. Even though WBN Unit 2 is not yet irradiated, TVA has decided to withdraw the previous commitment to replace the X-750 alloy insert bolts since replacement is not a definite solution for a near term problem. |
| | If you should have any questions, please call Bill Crouch at (423) 365-2004. |
| | Respectfully, David Stinson Watts Bar Unit 2 Vice President cc: 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}} |
Letter Sequence Withdrawal |
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Results
Other: CNL-14-077, Responses to Degraded Voltage Issue Requests for Additional Information, ML102290358, ML102290360, ML102290361, ML102290362, ML102290363, ML102290364, ML102290365, ML102290366, ML102290367, ML102290368, ML102290383, ML102290384, ML102290385, ML102290386, ML102290387, ML102290388, ML102290389, ML102290390, ML102290391, ML102290392, ML102290403, ML102290404, ML102290405, ML102290406, ML102290407, ML102290408, ML102290409, ML102290410, ML102290411, ML102290414, ML102290439, ML102290440, ML102290441, ML102290442, ML102290443, ML102290444, ML102290445, ML102290446, ML102290447, ML102290448, ML102290458, ML102290459, ML102290460, ML102290461, ML102290462, ML102290463, ML102290464, ML102290465, ML102290466... further results
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MONTHYEARML1005500072010-03-11011 March 2010 Request for Additional Information Related to Licensee'S Final Safety Analysis Report Amendment 95 Related to Section 4.2.2, Reactor Vessel Internal Components Project stage: RAI ML1010405732010-04-0909 April 2010 Response to NRC Request for Additional Information Regarding Licensee'S Final Safety Analysis Report (FSAR) Amendment Related to Section 4.2.2, Reactor Vessel Internal Components. Project stage: Response to RAI ML1011303512010-05-0505 May 2010 Request for Withholding Information from Public Disclosure (Tac No. ME2731) Project stage: Withholding Request Acceptance ML1014500842010-06-23023 June 2010 Request for Additional Information Regarding Licensee'S Final Safety Analysis Report Amendment Related to Reactor Systems, Nuclear Performance and Code Review, Ansd Plant Systems Project stage: RAI ML1015402502010-06-24024 June 2010 Request for Additional Information Regarding Licensee'S Final Safety Analysis Report Amendment Related to Nuclear Performance and Code Review, Plant Systems, and Testing (Tac Nos. ME2731 and ME3091) Project stage: RAI ML1017903992010-06-28028 June 2010 Request for Additional Information (RAI) Regarding Licensee'S Final Safety Analysis Report Amendment Related to Section 4.2.2, Reactor Vessel Internal Components Project stage: Request ML1016200062010-06-29029 June 2010 Request for Additional Information Regarding Licensee'S Final Safety Analysis Report Amendment Related to Nuclear Performance and Code Review (Tac No. ME2731) Project stage: RAI ML1015304742010-07-0202 July 2010 Request for Additional Information Regarding Licensee'S Final Safety Analysis Report Amendment Related to Mechanical and Civil Engineering Systems Project stage: RAI ML1016000262010-07-0808 July 2010 Request for Additional Information Regarding Licensee'S Final Safety Analysis Report, Amendment Related to Quality and Vendor Branch Review Project stage: RAI ML1015303542010-07-12012 July 2010 Request for Additional Information Regarding Licensee'S Final Safety Analysis Report Amendment Related to Electrical Engineering Systems Project stage: RAI ML1018001562010-07-15015 July 2010 Request for Additional Information Regarding Licensee'S Final Safety Analysis Report Amendment Related to Chapter 8, Electric Power Project stage: RAI ML1023003272010-08-0505 August 2010 Final Safety Analysis Report Figure 9.2-4A (Dwg No. 1-47W845-5, R38) Project stage: Other ML1022904642010-08-0505 August 2010 Final Safety Analysis Report Figure 9.2-1 (Dwg No. 1-47W845-1, R56) Project stage: Other ML1023003282010-08-0505 August 2010 Final Safety Analysis Report Figure 9.2-4B (Dwg No. 1-47W845-7, R14) Project stage: Other ML1023003292010-08-0505 August 2010 Final Safety Analysis Report Figure 9.2-5 (Dwg No. 1-47W611-67-1, R8) Project stage: Other ML1023003302010-08-0505 August 2010 Final Safety Analysis Report Figure 9.2-6 (Dwg No. 1-47W611-67-2, R5) Project stage: Other ML1023003312010-08-0505 August 2010 Final Safety Analysis Report Figure 9.2-8 (Dwg No. 1-47W611-67-4, R5) Project stage: Other ML1023003322010-08-0505 August 2010 Final Safety Analysis Report Figure 9.2-9 (Dwg No. 1-47W611-67-5, R10) Project stage: Other ML1023003332010-08-0505 August 2010 Final Safety Analysis Report Figure 9.2-10 (Dwg No. 1-47W610-67-1, R27) Project stage: Other ML1023003342010-08-0505 August 2010 Final Safety Analysis Report Figure 9.2-10 Sh a (Dwg No. 1-47W610-67-1A, R16) Project stage: Other ML1023003352010-08-0505 August 2010 Final Safety Analysis Report Figure 9.2-11 (Dwg No. 1-47W610-67-2, R15) Project stage: Other ML1023003432010-08-0505 August 2010 Final Safety Analysis Report Figure 9.2-12 Sh a (Dwg No. 1-47W610-67-3A, R7) Project stage: Other ML1023003442010-08-0505 August 2010 Final Safety Analysis Report Figure 9.2-13 (Dwg No. 1-47W610-67-4, R17) Project stage: Other ML1023003452010-08-0505 August 2010 Final Safety Analysis Report Figure 9.2-11 Sh a (Dwg No. 1-47W610-67-2A, R8) Project stage: Other ML1023003462010-08-0505 August 2010 Final Safety Analysis Report Figure 9.2-12 (Dwg No. 1-47W610-67-3, R12) Project stage: Other ML1023003472010-08-0505 August 2010 Final Safety Analysis Report Figure 9.2-14 (Dwg No. 1-47W610-67-5, R14) Project stage: Other ML1023003482010-08-0505 August 2010 Final Safety Analysis Report Figure 9.2-14 (Dwg No. 1-47W610-67-5A, R2) Project stage: Other ML1023003492010-08-0505 August 2010 Final Safety Analysis Report Figure 9.2-16 (Dwg No. 1-47W859-4, R23) Project stage: Other ML1023003502010-08-0505 August 2010 Final Safety Analysis Report Figure 9.2-17 (Dwg No. 1-47W859-3, R18) Project stage: Other ML1023003512010-08-0505 August 2010 Final Safety Analysis Report Figure 9.2-18 (Dwg No. 1-47W859-2, R36) Project stage: Other ML1023003522010-08-0505 August 2010 Final Safety Analysis Report Figure 9.2-19 (Dwg No. 1-47W859-1, R47) Project stage: Other ML1023003602010-08-0505 August 2010 Final Safety Analysis Report Figure 9.2-23 (Dwg No. 1-47W611-70-1, R9) Project stage: Other ML1023003612010-08-0505 August 2010 Final Safety Analysis Report Figure 9.2-20 (Dwg No. 1-47W610-70-1, R23) Project stage: Other ML1023003622010-08-0505 August 2010 Final Safety Analysis Report Figure 9.2-21 (Dwg No. 1-47W610-70-2, R29) Project stage: Other ML1023003632010-08-0505 August 2010 Final Safety Analysis Report Figure 9.2-21A (Dwg No. 1-47W610-70-2A, R15) Project stage: Other ML1023003642010-08-0505 August 2010 Final Safety Analysis Report Figure 9.2-22 (Dwg No. 1-47W610-70-3, R17) Project stage: Other ML1023003652010-08-0505 August 2010 Final Safety Analysis Report Figure 9.2-24 (Dwg No. 1-47W611-70-2, R11) Project stage: Other ML1023003672010-08-0505 August 2010 Final Safety Analysis Report Figure 9.2-25 (Dwg No. 1-47W611-70-3, R4) Project stage: Other ML1023003682010-08-0505 August 2010 Final Safety Analysis Report Figure 9.2-25A (Dwg No. 1-47W611-70-4, R4) Project stage: Other ML1023003692010-08-0505 August 2010 Final Safety Analysis Report Figure 9.3-1 (Dwg No. 1-47W610-32-1, R15) Project stage: Other ML1023003962010-08-0505 August 2010 Final Safety Analysis Report Figure 9.5-25 (Dwg No. 1-47W610-82-1, R18) Project stage: Other ML1022903582010-08-0505 August 2010 Final Safety Analysis Report Figure 8.1.2 (Dwg No. 1-15E500-1, R31) Project stage: Other ML1022903602010-08-0505 August 2010 Final Safety Analysis Report Figure 8.1-2A (Dwg No. 1-15E500-2, R39) Project stage: Other ML1022903612010-08-0505 August 2010 Final Safety Analysis Report Figure 8.1-2B (Dwg No. 1-15E500-3, R19) Project stage: Other ML1022903622010-08-0505 August 2010 Final Safety Analysis Report Figure 8.1-3 (Dwg No. 1-45W700-1, R28) Project stage: Other ML1022903632010-08-0505 August 2010 Final Safety Analysis Report Figure 8.2-1 (Dwg No. 1-75W500, R18) Project stage: Other ML1022903642010-08-0505 August 2010 Final Safety Analysis Report Figure 8.3-6 (Dwg No. 1-45W760-211-8, R14) Project stage: Other ML1022903652010-08-0505 August 2010 Final Safety Analysis Report Figure 8.3-7 (Dwg No. 1-45W760-211-9, R16) Project stage: Other ML1022903662010-08-0505 August 2010 Final Safety Analysis Report Figure 8.3-8 (Dwg No. 1-45W760-211-10, R12) Project stage: Other ML1022903672010-08-0505 August 2010 Final Safety Analysis Report Figure 8.3-9 (Dwg No. 1-45W760-211-11, R13) Project stage: Other 2010-06-28
[Table View] |
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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. 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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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Text
Tennessee Valley Authority, Post Office Box 2000, Spring City, Tennessee 37381-2000 April 21, 2011 10 CFR 50.34 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 - WITHDRAWAL OF A PREVIOUS COMMITMENT
Reference:
TVA letter dated June 28, 2010, Watts Bar Nuclear Plant (WBN) Unit 2 -
Request for Additional Information (RAI) Regarding Licensees Final Safety Analysis Report Amendment Related to Section 4.2.2, Reactor Vessel Internal Components (TAC No. ME2731)
The purpose of this letter is to withdraw a previous commitment made in the referenced letter.
In that letter, TVA committed to replace prior to Unit 2 operation the current Unit 2 clevis insert bolts to a design which uses X-750 alloy with a high temperature heat (HTH) treatment, rolled threads, and a larger radius on the undercut of the cap screw head. Upon further evaluation, TVA has determined that this replacement is unwarranted at this time.
The justification for this withdrawal stems from the fact that the bolting failure phenomenon has only known to have occurred at one unit in the industry. The phenomenon appears to be time based, and the breakage only occurs after many operating cycles. In discussions with personnel at the affected plant, TVA has learned that the cause is not yet known and that any change might be at best neutral to solving the problem. TVA has also confirmed via these discussions that bolting at the affected plants other unit does not have the same issue. In addition, WBN Unit 1 has operated with the same type bolting since 1995 with no failure of these bolts.
The initial NRC RAI cited the Staff Requirements Memorandum dated July 25, 2007 (ADAMS Accession No. ML093370274) directing TVA to look for opportunities to resolve issues where the unirradiated state of WBN Unit Bar 2 makes the issue easier to resolve. At this time, the root cause of the subject issue has not been determined, an industry resolution has not been established, the problem appears to be restricted to a single unit at another utility, and WBN
U.S. Nuclear Regulatory Commission Page 2 April 21, 2011 Unit 1 has operated with the X-750 bolting approximately sixteen years with no failure of these bolts. Even though WBN Unit 2 is not yet irradiated, TVA has decided to withdraw the previous commitment to replace the X-750 alloy insert bolts since replacement is not a definite solution for a near term problem.
If you should have any questions, please call Bill Crouch at (423) 365-2004.
Respectfully, David Stinson Watts Bar Unit 2 Vice President cc: 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