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MONTHYEARML1014504112010-05-19019 May 2010 Cycle 16 - 180-Day Steam Generator Inspection Report Project stage: Request ML1014800182010-06-0707 June 2010 Request for Additional Information Regarding the 90-Day and 180-Day Steam Generator Tube Inspection Reports for Cycle 16 Refueling Outage Project stage: RAI ML1020202002010-07-16016 July 2010 Response to Request for Additional Information Regarding the 90-Day and 180-Day Steam Generator Tube Inspection Reports for Cycle 16 Refueling Outage Project stage: Response to RAI ML1022905322010-08-0202 August 2010 SG Tube ISI RAIs Project stage: Other ML1023001742010-08-13013 August 2010 Response to Request for Clarification of Response to Request for Additional Information Regarding the 90-Day and 180-Day Steam Generator Tube Inspection Reports for Cycle 16 Refueling Outage, Dated July 16, 2010 Project stage: Response to RAI ML1024304462010-08-31031 August 2010 SQN 2 SG ISI Report Clarification Project stage: Other 2010-07-16
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Category:Letter
MONTHYEARML24032A0202024-01-31031 January 2024 NPDES Biocide/Corrosion Treatment Plan Annual Report, Cy 2023 ML23319A2452024-01-29029 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 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 ML24018A0142024-01-17017 January 2024 Engine Systems, Inc., Report No. 10CFR21-0137, Rev. 1, 56913-EN 56913 ML24011A3182024-01-11011 January 2024 Submittal of Discharge Monitoring Report (Dmr), October 2023 ML24011A3172024-01-11011 January 2024 Submittal of Discharge Monitoring Report (Dmr), September 2023 ML24011A3202024-01-11011 January 2024 Submittal of Discharge Monitoring Report (Dmr), December 2023 ML24011A3162024-01-11011 January 2024 Submittal of Discharge Monitoring Report (Dmr), August 2023 ML24011A3192024-01-11011 January 2024 Submittal of Discharge Monitoring Report (Dmr), November 2023 IR 05000327/20234422024-01-11011 January 2024 95001 Supplemental Inspection Report 05000327/2023442 and 05000328/2023442 and Follow-Up Assessment Letter ML24010A2132024-01-10010 January 2024 CFR 21.21 Final Report Regarding Siemens Medium Voltage Circuit Breakers ML24018A0952024-01-0404 January 2024 Engine Systems, Inc., 10CFR21 Reporting of Defects and Non-Compliance Report No. 10CFR21-0137, Rev. 0 ML24004A0332024-01-0303 January 2024 Interim Report of a Deviation or Failure to Comply Crompton Instruments Type 077 Ammeter ML24004A0402024-01-0303 January 2024 Response to NRCs November 8, 2023, Request for Additional Information - Related to Independent Spent Fuel Storage Installation CNL-23-068, 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 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) ML23346A1222023-12-12012 December 2023 Annual Non-Radiological Environmental Operating Report - 2023 IR 05000327/20234202023-11-28028 November 2023 Security Baseline Inspection Report 05000327/2023420 and 05000328/2023420 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 ML23324A4362023-11-0909 November 2023 Exam Corporate Notification Letter Aka 210-day Letter ML23307A0822023-11-0808 November 2023 Request for Additional Information August 4, 2022, Exemption Request for Deviating from the Conditions of Certificate of Compliance No. 1032, Amendment No. 3, Related to Sequoyah Nuclear Plant Independent Spent Fuel Storage Installation IR 05000327/20230032023-11-0303 November 2023 Integrated Inspection Report 05000327/2023003 and 05000328/2023003 ML23306A1592023-11-0202 November 2023 Enforcement Action EA-22-129 Inspection Readiness Notification ML23292A0792023-10-19019 October 2023 Tennessee Valley Authority - Emergency Plan Implementing Procedure Revision, Includes EPIP-5, Revision 58, General Emergency IR 05000327/20230112023-10-16016 October 2023 Triennial Fire Protection Inspection Report 05000327/2023011 and 05000328/2023011 ML23285A0882023-10-12012 October 2023 Submittal of Sequoyah Nuclear Plant, Units 1 and 2, Submittal of Updated Final Safety Analysis Report Amendment 31 ML23284A4252023-10-11011 October 2023 10 CFR 50.59 and 10 CFR 72.48 Changes, Tests, and Experiments Summary Report; Commitment Summary Report; and Update to the Fire Protection Report ML23283A2792023-10-10010 October 2023 Revisions to the Sequoyah Nuclear Plant Units 1 and 2 Technical Requirements Manual ML23279A0612023-10-0505 October 2023 Paragon Energy Solutions LLC, Part 21 Final Report Re Potential Defect with Eaton Jd and Hjd Series Molded Case Circuit Breakers (Mccbs) ML23277A0462023-10-0404 October 2023 Revisions to the Sequoyah Nuclear Plant Units 1 and 2 Technical Specification Bases ML23275A0272023-09-29029 September 2023 Submittal of Discharge Monitoring Report (DMR) Quality Assurance Study 43 Final Report 2023 ML23271A1662023-09-28028 September 2023 Registration of Spent Fuel Storage Cask Pursuant to 10 CFR 72.212(b)(2) 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 IR 05000327/20234032023-09-14014 September 2023 Cyber Security Inspection Report 05000327/2023403 and 05000328/2023403 (Cover Letter) ML23257A0062023-09-14014 September 2023 Enforcement Action EA-22-129 Inspection Postponement Request ML23254A2192023-09-11011 September 2023 Emergency Plan Implementing Procedure Revisions ML23254A0652023-09-0707 September 2023 Registration of Spent Fuel Storage Cask Pursuant to 10 CFR 72.212(b)(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 05000327/20230052023-08-29029 August 2023 Updated Inspection Plan for Sequoyah Nuclear Plant, Units 1 and 2 - Report 05000327/2023005 and 05000328/2023005 ML23233A0122023-08-17017 August 2023 Unit 1 Cycle 25 Refueling Outage - 90-Day Inservice Inspection Summary Report - Supplement ML23233A0142023-08-15015 August 2023 Discharge Monitoring Report (Dmr), July 2023 ML23215A1212023-08-0303 August 2023 301 Exam Administrative Items (2B) Normal Release ML23215A1572023-08-0303 August 2023 Enforcement Action EA-22-129 Inspection Readiness Notification 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 2024-01-04
[Table view] Category:Request for Additional Information (RAI)
MONTHYEARML23307A0832023-11-0808 November 2023 Enclosure - Request for Additional Information HDI-Sequoyah NDE Exemption Request 10-30-2023 ML23307A0822023-11-0808 November 2023 Request for Additional Information August 4, 2022, Exemption Request for Deviating from the Conditions of Certificate of Compliance No. 1032, Amendment No. 3, Related to Sequoyah Nuclear Plant Independent Spent Fuel Storage Installation ML23062A5952023-02-27027 February 2023 Staff follow-up Questions to Tva'S 12/19/2022 Response of the Staff'S Rsi Regarding 08/04/2022 SQN Exemption Request ML23062A5942023-02-27027 February 2023 Enclosure - NRC SQN Exemption Rsi Response Staff Follow Up Questions ML22343A0692022-12-0808 December 2022 NRR E-mail Capture - Request for Additional Information - Sequoyah Nuclear Plant, Units 1 and 2, and Watts Bar Nuclear Plant, Units 1 and 2, License Amendment Request to Revise Technical Specification 3.4.12 (L-2022-LLA-0103) ML22257A0622022-09-14014 September 2022 Requalification Program Inspection - Sequoyah Nuclear Plant ML22255A0842022-09-0909 September 2022 Document Request for Sequoyah Nuclear Plant - Radiation Protection Inspection - Inspection Report 2022-04 ML22227A0272022-08-11011 August 2022 NRR E-mail Capture - Request for Additional Information Related to Alternative Requests RP-11 for Sequoyah Nuclear Plant, Units 1 and 2, and IST-RR-9 for Watts Bar Nuclear Plant, Units 1 and 2 ML22214A1582022-08-0202 August 2022 NRR E-mail Capture - Request for Additional Information for Sequoyah Units 1 and 2 License Amendment Request for Fire and Seismic PRA Modification to 10 CFR 50.69 (L-2022-LLA-0033) ML22151A0102022-05-27027 May 2022 NRR E-mail Capture - Revised Request for Additional Information Re Sequoyah Nuclear Plant Alternative Request RV-02 ML22151A0092022-05-26026 May 2022 NRR E-mail Capture - Request for Additional Information Re Sequoyah Nuclear Plant Alternative Request RV-02 ML22146A3322022-05-26026 May 2022 NRR E-mail Capture - Request for Additional Information Related to Sequoyah Nuclear Plant'S LAR to Adopt TSTF-505 ML22144A1002022-05-12012 May 2022 NRR E-mail Capture - Request for Additional Information Related to Tva'S Request to Revised the TVA Plants' Radiological Emergency Plans ML21237A4952021-08-25025 August 2021 Document Request for Sequoyah Nuclear Plant - Radiation Protection Inspection - Inspection Report 2021-04 ML21160A0352021-06-0303 June 2021 Document Request for Sequoyah Nuclear Plant - Radiation Protection Inspection - Inspection Report 2021-03 ML21095A0482021-04-0505 April 2021 NRR E-mail Capture - Sequoyah Nuclear Plant, Units 1 and 2 - Request for Additional Information Regarding Request to Transition to Westinghouse Fuel ML21092A0972021-04-0202 April 2021 Notification of Inspection and Request for Information for NRC Problem Identification and Resolution Inspection ML20259A4782020-09-15015 September 2020 Emergency Preparedness Program Inspection Request for Information ML20261H4172020-09-14014 September 2020 NRR E-mail Capture - Sequoyah Nuclear Plant, Units 1 and 2 - Request for Additional Information Regarding Hydrologic UFSAR Update ML20261H4162020-09-0202 September 2020 NRR E-mail Capture - Draft Request for Additional Information - Sequoyah Nuclear Plant, Units 1 and 2, Request to Revise UFSAR Hydrologic Analysis ML20189A2112020-07-0101 July 2020 Request for Additional Information Regarding Hydrologic UFSAR Update ML20106F1042020-04-14014 April 2020 Request for Additional Information Regarding the Hydrologic Analysis LAR ML20161A3902020-04-0909 April 2020 Request for Supporting Information for the Sequoyah SPRA Audit Review - Follow-up to Plant Response Question 5 ML20098D8612020-04-0707 April 2020 Notification of an NRC Fire Protection Team Inspection (FPTI) (NRC Inspection Report 05000327/2020012 and 05000328/2020012) and Request for Information) ML20036E2842020-02-0505 February 2020 20200123 - Sequoyah Radiation Safety Inspection Document Request Letter ML19323D7562019-11-18018 November 2019 Nrc'S Request for Additional Information - Exigent Amendment ML19235A0992019-08-22022 August 2019 Emergency Preparedness Program Inspection Request for Information ML19162A2462019-06-11011 June 2019 RP Inspection Document Request 2019-03 ML19149A6222019-05-29029 May 2019 NRR E-mail Capture - Request for Additional Information - Sequoyah Nuclear Plant, Units 1 and 2, Request for Alternative to 18-ISI-1 EPID: L-2019-LLR-0006 ML19148A7912019-05-28028 May 2019 NRR E-mail Capture - Sequoyah Nuclear Plant and Watts Bar Nuclear Plant - Final Request for Additional Information Related to Request for Alternative to OM Code Requirements ML19015A4192019-01-15015 January 2019 NRR E-mail Capture - RAI - Sequoyah Nuclear Plant, Units 1 and 2, LAR to Adopt 10 CFR50.69 Risk-informed SSC ML18344A0752018-12-10010 December 2018 NRR E-mail Capture - Request for Additional Information - Sequoyah 1 and 2, Request to Modify Essential Raw Cooling Water Motor Control Center Breakers and to Revise Updated Final Analysis Report (SQN-TS-17-04) ML18296A0022018-10-22022 October 2018 NRR E-mail Capture - Additional Information Needs - Sequoyah Units 1 and 2, Request to Modify Essential Raw Cooling Water Motor Control Center Breakers Revise Updated Final Analysis Report (SQN-TS-17-04) ML18283B0592018-10-10010 October 2018 NRR E-mail Capture - Additional Information Needs Identified During Audit - Sequoyah 1 and 2, Request to Modify Essential Raw Cooling Water Motor Control Center Breakers Revise Updated Final Analysis Report (SQN-TS-17-04) ML18283A6232018-09-25025 September 2018 04 RP Inspection Document Request ML18233A1942018-08-21021 August 2018 NRR E-mail Capture - Additional Information Needs Identified - Sequoyah 1 and 2, Request to Modify Essential Raw Cooling Water Motor Control Center Breakers and to Revise Updated Final Analysis Report (SQN-TS-17-04) ML18138A1102018-05-17017 May 2018 Enclosurequest for Additional Information (Letter to E. D. Schrull Request for Additional Information Regarding Tennessee Valley Authority'S Decommissioning Funding Plan Update for Browns Ferry and Sequoyah Isfsis) ML18057A6372018-02-23023 February 2018 NRR E-mail Capture - Request for Additional Information Related to TVA Fleet Topical Report TVA-NPG-AWA16 - EPIC: L-2016-TOP-0011) ML17191A2062017-07-0606 July 2017 NRR E-mail Capture - Sequoyah Nuclear Station, Unit 1 & 2 - Request for Additional Information Related to LAR for Technical Specification 3.8.1.17 Note Modification (CAC Nos. MF9398 and MF9399) ML17150A0792017-05-23023 May 2017 NRR E-mail Capture - Request for Additional Information Related to TVA Fleet LAR for EAL Change to Adopt NEI-99-01 Rev.6 (CAC Nos. MF9054 - MF9060) ML17112A0402017-04-20020 April 2017 NRR E-mail Capture - Sequoyah Nuclear Station, Unit 1 & 2 - Request for Additional Information Related to LAR for Technical Specification 3.8.1, AC SOURCES-OPERATING ML17004A0612017-01-0404 January 2017 Notification of NRC Triennial Fire Protection Inspection (Team)(Report 05000327/2017007 and 05000328/2017007) ML15194A3882015-07-13013 July 2015 Request for Additional Information Related to LAR to Revise Ice Condenser Ice Mas Tech Spec ML15175A2912015-06-24024 June 2015 E-mail Re. Request for Additional Information RR RP-07 ML15159B1642015-06-22022 June 2015 Requests for Additional Information for the Review of the Sequoyah Nuclear Plant, Units 1 and 2, License Renewal Application-Set 25 (TAC Nos. MF0481 and MF0482) ML15050A0962015-02-19019 February 2015 E-mail Re. Request for Additional Information Related to LAR to Ice Condendser Inc Mass Tech Spec ML15042A4702015-02-11011 February 2015 E-mail Re. Request for Additional Information Related to License Amendment Request to Revise Technical Specification on Ultimate Heat Sink ML14318A8052014-11-12012 November 2014 Requalification Program Inspection - Sequoyah Nuclear Plant ML14254A2042014-09-22022 September 2014 Requests for Additional Information for the Review of the Sequoyah Nuclear Plant, Units 1 and 2, License Renewal Application - Set 22 (TAC Nos. MF0481 and MF0482) ML14220A2132014-08-0808 August 2014 E-mail Re. Request for Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard 805 2023-02-27
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UNITED NUCLEAR REGULATORY WASHINGTON, D.C. 20555-0001 June 7, 2010 Mr. Rodney 1\/1. Krich Vice President, Nuclear Licensing Tennessee Valley Authority 3R Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 SEQUOYAH NUCLEAR PLANT, UNIT 2 -REQUEST FOR ADDITIONAL INFORMATION REGARDING THE 90-DAY AND 180-DAY STEAM GENERATOR TUBE INSPECTION REPORTS FOR CYCLE 16 REFUELING OUTAGE (TAC NOS. ME3400 AND ME3971)
Dear Mr. Krich:
By letters dated February 19 and May 19, 2010, Tennessee Valley Authority submitted 90-day and 180-day steam generator tube inspection reports, respectively for the Cycle 16 refueling outage (fall 2009) in accordance with Technical Specification Section 6.9.1.16.2 for Sequoyah Nuclear Plant, Unit 2. The Nuclear Regulatory Commission staff is reviewing the submittal and has determined that additional information is required to complete its evaluation.
The enclosed request for additional information was discussed with Mr. Rodney Cook of your staff on June 2, 2010, and it was agreed that a response would be provided by July 16, 2010. If you have any questions regarding this matter, I can be reached at 301-415-1564.
Sincerely, Siva P. Lingam, Project Manager Plant Licensing Branch 11-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-328
Enclosure:
Request for Additional Information cc w/encl: Distribution via Listserv REOUEST FOR ADDITIONAL INFORMATION REGARDING THE CYCLE 16 90-DAYand 180-DAY STEAM GENERATOR TUBE INSPECTION REPORTS SEOUOYAH NUCLEAR PLANT, UNIT 2 DOCKET NO. 50-328 By letters dated February 19 and May 19, 2010 (Agencywide Documents Access and Management System (ADAMS) Accession Nos. ML 100550767 and ML 101450411, respectively), Tennessee Valley Authority submitted the Cycle 16 refueling outage (fall 2009) 90-day and 180-day steam generator tube inspection reports, respectively, per Technical Specification Section 6.9.1.16.2 for Sequoyah Nuclear Plant (SON), Unit2. In addition to these reports, the U.S. Nuclear Regulatory Commission (NRC) staff summarized additional information concerning the 2009 SG tube inspections at SON, Unit 2 in a letter dated December 10, 2009 (ADAMS Accession No. ML093360644).
In order to complete its review of the above documents, the NRC staff needs the following additional information: Please discuss the scope and results of your secondary side steam drum inspections. Prior to shutting down for your fall 2009 steam generator tube inspections, a small primary-to-secondary leak rate existed. Please discuss whether any leakage was observed after starting up from the fall 2009 refueling outage (RFO). If so, discuss the possible source of any leakage and any implications for your inspection and repair criteria. On page E 1-10 of your February 19, 2010, letter, it was indicated that the voltage growth was determined based on the historic review of 3743 distorted support indications.
Please confirm this number since you detected 3747 indications at the supports, which included five indications that were only identified with a rotating probe. Please confirm that for every support indication identified during the fall 2009 RFO, you reviewed the historic data to determine if an indication was present; and, if an indication was present, you determined the growth rate of that indication and included it in your growth rate distribution. From Table 4-7 of your February 19, 2010, letter, the number of tubes examined on the cold-leg was calculated to be 3189. This is two tubes less than the number of tubes in service. Please discuss whether the cold-leg portion of each tube was examined with a bobbin coil probe. If not, discuss how this was accounted for in your operational assessment. In steam generators 2 and 3 (Tables 4-7 and 4-8 of your February 19, 2010, letter, respectively) the ratio of new indications in tubes tested with worn probes is higher than the ratio of new indications in tubes tested with good probes. This possibly indicates that the worn probes are missing indications (although the overall average from all four steam generators indicates that the ratios of these two quantities are comparable).
Please Enclosure
-2 discuss any corrective action taken in response to these results or discuss why no corrective action was needed. The largest indication of outside diameter stress corrosion cracking (ODSCC) at the tube support elevations grew from approximately 0.4 volts in 2008 to 6.6 volts in 2009. The 0.4 volt indication in 2008 had been inspected with a worn probe. Please discuss any insights on the reason for such a high growth rate. For example, is the growth rate of indications in tubes inspected with a worn probe significantly higher than the growth rate of indications in tubes inspected with "good" probes (Le., probes that passed the probe wear criterion)? During the fall 2009 RFO, the voltages of two of the indications of outside diameter stress corrosion cracking at the tube support plates exceeded your projections.
The methodology for projecting the end-of-cycle voltage distribution for such indications was intended to be conservative in terms of projecting the number and severity of the flaws (and therefore conservative in estimating the accident induced leakage and burst probability).
This under prediction in the severity of the indications led to under predicting the burst probability in steam generator
- 4. Although no performance criteria were exceeded, the results appear to question the conservatisms of the methodology and may become a safety concern if your projections become closer to the performance criteria.
Given these results, please discuss whether any changes to your assessment methodology are needed to ensure your projections will be conservative. On page E2-2 of your February 19, 2010, letter, you reported the operational assessment leakage for "GL [Generic Letter] 95-05" flaws as 1.760 gallons per minute. This value does not match the most limiting value reported on page E 1-82 of that letter. Please clarify. Please clarify the first sentence of the second paragraph on page E2-2 of your February 19, 2010, letter. In particular, confirm that you assessed the leakage contribution from all primary water and outside diameter stress corrosion cracking indications at or below the top of the tubesheet in your condition monitoring and operational assessment.
- 10. Please discuss whether any of the tubes had the bottom of the WEXTEX transition located more than 2.88-inches below the top of the tubesheet.
If so, discuss how many tubes had this condition.
- 11. Please clarify the indication and location columns in Table 2 on page E2-5 of your February 19, 2010, letter. In particular address why there are two indication columns, two "location 1" columns, and two "location 2" columns. 12. Several ODSCC indications were reported in the tubesheet region. Please discuss whether these indications were below the bottom of the expansion transition.
If so, discuss how a corrosive environment was achieved below the bottom of the WEXTEX transition (e.g., did the tube lose contact with the tubesheet).
If the tube is not in contact with the tubesheet, discuss any implications to W*.
-13. Two indications were attributed to wear from a loose part in steam generator
- 4. A possible loose part signal was not evident in the eddy current data. Please discuss whether a visual inspection was performed to confirm the absence of a loose part at these locations.
Since a loose part may not be conductive or may be a small distance away from the tube and therefore not detected during the eddy current examination, discuss whether an assessment was performed for the continued wear of these tubes. If not, discuss why not. 14. On page 6 of 101 in the May 19, 2010, letter, it was indicated that twelve indications of axial OOSCC was detected in the free span region in three tubes. This appears to contradict the information on page 4 of 101 where four tubes are identified as being plugged for this degradation mechanism.
Is this difference a result of counting the one tube that was plugged for axial OOSCC in the sludge pile region as an axial OOSCC indication in the free span? If not, please explain the difference.
- 15. On page 8 of 101 in the May 19, 2010, letter, it was indicated that the U2C15 operational assessment predicted the limiting accident leakage to be 1.34 gallons per minute and the limiting burst pressure as 4.55E-4. These values do not appear to match those reported on page 5-6 of your February 19, 2010, letter. Please clarify. 16. Please clarify the nature of the geometry affect at the first tube support plate intersection in the tube that was preventively plugged.
Mr. Rodney M. Krich Vice President, Nuclear Licensing Tennessee Valley Authority 3R Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 SEQUOYAH NUCLEAR PLANT, UNIT 2 -REQUEST FOR ADDITIONAL INFORMATION REGARDING THE 90-DAY AND 180-DAY STEAM GENERATOR TUBE INSPECTION REPORTS FOR CYCLE 16 REFUELING OUTAGE (TAC NOS. ME3400 AND ME3971)
Dear Mr. Krich:
By letters dated February 19 and May 19, 2010, Tennessee Valley Authority submitted 90-day and 180-day steam generator tube inspection reports, respectively for the Cycle 16 refueling outage (fall 2009) in accordance with Technical Specification Section 6.9.1.16.2 for Sequoyah Nuclear Plant, Unit 2. The Nuclear Regulatory Commission staff is reviewing the submittal and has determined that additional information is required to complete its evaluation.
The enclosed request for additional information was discussed with Mr. Rodney Cook of your staff on June 2, 2010, and it was agreed that a response would be provided by July 16, 2010. If you have any questions regarding this matter, I can be reached at 301-415-1564.
Sincerely, IRA! Siva P. Lingam, Project Manager Plant Licensing Branch 11-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-328
Enclosure:
Request for Additional Information cc w/encl: Distribution via Listserv DISTRIBUTION:
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