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MONTHYEARML21272A2002021-09-29029 September 2021
NRR E-mail Capture - Comanche Peak Unit 2 - Upcoming Steam Generator Tube Inservice Inspection (L-2021-NFO-0013)
Project stage: Other
ML22020A1782022-01-31031 January 2022
Summary of Conference Call Regarding the Fall 2021 Steam Generator Tube Inspections
Project stage: Other
2021-09-29
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Category:Meeting Summary
MONTHYEARML24019A0342024-01-30030 January 2024
Public Meeting Summary - 01-04-2024 - Comanche Peak LRA - Structures Monitoring Program
ML23255A0622023-09-18018 September 2023
Summary of August 7, 2023, Presubmittal Meeting with Vistra Operations Company LLC to Discuss the Proposed LAR to Relocate Refueling Operations TS 3.9.3, Nuclear Instrumentation, to the Technical Requirements Manual
ML23132A1572023-05-18018 May 2023
Summary of the License Renewal Environmental Audit (EPID Number: L-2022-LNE-004) (Docket Numbers 50-445 and 50-446)
ML23103A3002023-04-14014 April 2023
Summary of March 28, 2023, Presubmittal Meeting with Vistra Operations Company LLC to Discuss Proposed LAR to Take Exception to RG 1.81, Rev. 1, Shared Emergency and Shutdown Electric Systems for Multi-Unit Nuclear Power Plants,
ML23081A5232023-04-12012 April 2023
Public Scoping Meeting for Environmental Review of Comanche Peak Nuclear Power Plant (Cpnpp), Unit Nos. 1 and 2 License Renewal Application
ML23101A0432023-04-12012 April 2023
April 6, 2023, Summary of Meeting with Vistra Operations Company LLC to Discuss Proposed Alternative Regarding Inservice Testing of Various Thermal Relief Valves for Comanche Peak Nuclear Power Plant, Unit Nos. 1 and 2
ML22151A1842022-06-22022 June 2022
License Renewal Application May 26, 2022 Pre-submittal Public Meeting Summary
ML22147A0932022-06-0606 June 2022
2021 Annual Assessment Public Meeting Summary
ML22020A1782022-01-31031 January 2022
Summary of Conference Call Regarding the Fall 2021 Steam Generator Tube Inspections
ML21259A1492021-10-26026 October 2021
CPNPP, Unit Nos. 1 and 2 - Meeting Summary for Environmental Pre Submittal Meeting for Initial License Renewal Application on September 21, 2021
ML21259A1402021-10-0505 October 2021
Meeting Summary for Safety Pre Submittal Meeting for Initial License Renewal Application on September 21, 2021
ML21140A3892021-05-24024 May 2021
Riv Column 1 EOC 2020 Public Meeting Summary
ML21130A6832021-05-20020 May 2021
Summary of April 7, 2021, Presubmittal Meeting with Vistra Operations Company LLC Regarding the Proposed Exemption Request to Defer the Annual Force-On-Force Exercise for Comanche Peak Nuclear Power Plant, Unit Nos. 1 and 2
ML21124A0072021-05-10010 May 2021
Meeting Summary for Environmental Pre-Submittal Meeting for Initial License Renewal Application
ML21110A0602021-05-0707 May 2021
Summary of April 6, 2021, Meeting with Vistra Operations Company LLC to Defer the Biennial Emergency Planning Exercise for Comanche Peak Nuclear Power Plant, Unit Nos. 1 and 2
ML21099A2752021-04-15015 April 2021
Summary of Teleconference with Vistra Operations Company LLC to Discuss Proposed LAR to Adopt TSTF-505, Rev. 2, to Provide Risk-Informed Extended Completion Times for Comanche Peak, Units 1 and 2
ML20351A2592021-01-0505 January 2021
Summary of November 12, 2020, Teleconference with Vistra Operations Company LLC Proposed License Amendment Request for One-Time TS Revision to Replace Station Service Water Pump
ML20189A2832020-07-0707 July 2020
Summary of Region IV Annual Assessment Public Meeting
ML20115E3932020-04-30030 April 2020
Summary of April 6 and 7, 2020, COVID-19 Related Presubmittal Teleconferences with Vistra Operations Company LLC to Discuss Licensing Actions Supporting the Comanche Peak Unit No. 2 Spring 2020 Refueling Outage
ML20044D3052020-02-26026 February 2020
Summary of Teleconference with Vistra Operations Company, LLC to Discuss a Proposed License Amendment Request for Changes to Certain Emergency Action Levels for Comanche Peak Nuclear Power Plant, Unit Nos. 1 and 2 (EPID L-2020-LRM-000
ML19352E3172020-01-0808 January 2020
Summary of Teleconference with Vistra Operations Company LLC to Discuss a Proposed License Amendment Request to Change TS 3.8.1, AC Sources - Operating for Comanche Peak Nuclear Power Plant, Unit Nos. 1 and 2
ML19311C2122019-11-13013 November 2019
Summary of November 5, 2019, Teleconference with Vistra Operations Company LLC to Discuss a Proposed License Amendment Request to Change TS 3.8.1, Ac Sources - Operating for Comanche Peak Nuclear Power Plant, Unit Nos. 1 and 2
ML18275A3142018-10-16016 October 2018
Summary of September 17, 2018, Public Teleconference with Vistra Operations Company, LLC, on Proposed Changes to the Emergency Plan for Comanche Peak Nuclear Power Plant, Unit Nos. 1 and 2
ML17137A1742017-05-22022 May 2017
Summary of Conference Call Regarding the Spring 2017 Steam Generator Tube Inspections
ML16194A4962016-07-12012 July 2016
Summary of Annual Performance Assessment Meeting and Public Open House Regarding Comanche Peak Nuclear Power Plant 2015 Performance
ML15191A2282015-07-27027 July 2015
7/9/2015 Summary of Pre-submittal Meeting with Luminant Generation Company LLC to Discuss Submittal for License Amendment Request to Revise Technical Specification 3.8.1 for Comanche Peak Nuclear Power Plant, Units 1 and 2 (TACs MF6311 and
ML15191A2512015-07-0909 July 2015
July 9, 2015 Public Meeting: Comanch Peak Pre- Application Meeting, Emergency Diesel Generator Voltage and Frequency Technical Specification Changes
ML14188C4402014-07-22022 July 2014
6/3/2014 Summary of Meeting with Luminant Generation Company LLC to Discuss Proposed Modifications to Technical Specifications to Install Backup Transformer XST1A for Comanche Peak, Units 1 and 2
ML13067A0292013-03-15015 March 2013
2/28/13 - Summary of Meeting Via Conference Call with Luminant to Discuss Generic Safety Issue 191, Assessment of Debris Accumulation on PWR (Pressurized-Water Reactor) Sump Performance, for Comanche Peak, Units 1 and 2
ML12341A0812012-12-18018 December 2012
Summary of 11/15/12 Meeting with Luminant Generation Company LLC to Discuss Indirect License Transfers for Comanche Peak Nuclear Power Plant, Units 1 and 2
ML12332A3652012-12-18018 December 2012
Summary of Meeting with Luminant Generation Company LLC, to Discuss License Amendment Request for Approval of Revised Spent Fuel Criticality Analysis to Update Comanche Peak, Units 1 and 2, Technical Specifications (TAC Nos. ME8896-ME8897)
ML12283A3502012-10-25025 October 2012
Summary of 9/13/12 Meeting with Luminant Generation Company LLC to Discuss Proposed License Request for Approval of Revised Spent Fuel Criticality Analysis to Update Comanche Peak, Units 1 and 2, Technical Specifications
ML12229A5042012-09-19019 September 2012
8/6/2012 Summary of Conference Call with Luminant to Discuss Proposed License Amendment Request to Revise Technical Specification 3.8.1, AC Sources - Operating, to Support Installation of Backup Transformer at Comanche Peak, Units 1 and 2
ML12188A6972012-07-18018 July 2012
6/26/12 Summary of Meeting with Luminant Generation Company LLC to Discuss Proposed License Amendment Request to Revise TS 3.8.1, AC Sources - Operating, to Support Installation of Backup Transformer at Comanche Peak, Units 1 and 2 (TAC ME8
ML12072A3432012-03-12012 March 2012
3/6/2012 Summary of Meeting with Luminant Generation Company, LLC Regarding Planned Modifications to Resolve Fire Protection Circuit Interactions
ML1125904822011-10-14014 October 2011
Summary of Meeting with Luminant to Discuss Comanche Peak, Units 1 and 2, Proposed Request to Adopt Risk-Informed Technical Specification Task Force Initiative 8a, Relocate LCOs for RPS and ESFAS Instrumentation to Licensee Control
ML1114001482011-05-23023 May 2011
Summary of Conference Call on 4/14/2011 with Nrr/Dci/Csgb Regarding the Spring 2011 Steam Generator Tube Inspections
ML1114003142011-05-19019 May 2011
Summary of Public Meeting with Luminant Generation Company on Comanche Peak Nuclear Power Plant, Units 1 and 2, to Discuss 2010 End of Cycle Performance Assessment
ML1108004622011-03-28028 March 2011
3/17/11 Summary of Closed Meeting with Luminant Generation Company Via Conference Call to Discuss Generic Request for Additional Information Pertaining to Its Cyber Security Submittal
ML1101908002011-01-18018 January 2011
Summary of Meeting with Luminant Generation Company LLC Regarding a Preliminary Finding with Moderate Safety Significance
ML1034205662010-12-22022 December 2010
Memo Summary of the November 3, 2010, Public Meeting with the United States - Advanced Pressurized Water Reactor Design Centered Working Group to Discuss Inspections, Test, Analyses, and Acceptance Criteria, Conceptual Design Information.
ML1016501752010-06-21021 June 2010
6/10/10 Summary of Closed Meeting with Luminant Generation Company, LLC to Discuss Comanche Peak Nuclear Power Plant, Units 1 and 2 Implementation Plan/Information Pertaining to Defensive Strategy for Cyber Security Submittal
ML1013906402010-05-19019 May 2010
Summary of Public Meeting with Luminant Generation Company on Comanche Peak Nuclear Power Plant, Units 1 and 2, 2009 Performance
ML0924401642009-09-14014 September 2009
Meeting Summary, Pre-Application Meeting on with Luminant Generation Company LLC to Dicuss Future Amendment Request to Revise Comanche Peak Units 1 and 2 Startup Transformer Completion Times
ML0919705782009-07-31031 July 2009
Summary of Category 1 Meeting with Luminant Generation Company LLC, Resolution of Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors
ML0918303012009-07-0202 July 2009
Summary of Annual Performance Assessment Meeting for Comanche Peak Steam Electric Stations
ML0729204682007-10-29029 October 2007
09/25/2007, Summary of Meeting Between the U.S. Nuclear Regulatory Commission Staff and Strategic Teaming and Resource Sharing Representatives to Discuss License Renewal Activities
ML0720005052007-07-31031 July 2007
Summary of Meeting with Txu Generation Company LP to Discussed Regarding the Plans for Methodology Transition and Power Uprate
ML0717200702007-06-20020 June 2007
Summary of Meeting with Txu Power Regarding Comanche Peak Steam Electric Stations End-of-Cycle Assessment for 2006
ML0612204362006-05-18018 May 2006
Attachment 3 to Comanche Peak Conference Call
2024-01-30
[Table view] |
Text
January 31, 2022 Mr. Ken J. Peters Senior Vice President and Chief Nuclear Officer Attention: Regulatory Affairs Vistra Operations Company LLC Comanche Peak Nuclear Power Plant 6322 N FM 56 P.O. Box 1002 Glen Rose, TX 76043
SUBJECT:
COMANCHE PEAK NUCLEAR POWER PLANT, UNIT NO. 2 -
SUMMARY
OF CONFERENCE CALL REGARDING THE FALL 2021 STEAM GENERATOR TUBE INSPECTIONS (EPID L-2021-NFO-0013)
Dear Mr. Peters:
On November 4, 2021, the U.S. Nuclear Regulatory Commission staff participated in a conference call with representatives of Vistra Operations Company LLC (the licensee) regarding the ongoing steam generator tube inspection activities at Comanche Peak Nuclear Power Plant, Unit No. 2.
A summary of the conference call is provided in the enclosure..
If you have any questions, please contact me at 301-415-6256 or via e-mail at Dennis.Galvin@nrc.gov.
Sincerely,
/RA/
Dennis J. Galvin, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-446
Enclosure:
Conference Call Summary cc: Listserv
SUMMARY
OF NOVEMBER 4, 2021 CONFERENCE CALL REGARDING FALL 2021 STEAM GENERATOR TUBE INSPECTIONS AT COMANCHE PEAK NUCLEAR POWER PLANT, UNIT 2 DOCKET NO. 50-446 On November 4, 2021, the U.S. Nuclear Regulatory Commission (NRC) staff participated in a conference call with representatives of Vistra Operations Company, LLC (the licensee),
regarding the ongoing steam generator (SG) tube inspection activities at Comanche Peak Nuclear Power Plant, Unit No. 2 (Comanche Peak, Unit 2), during refueling outage 19. The licensee provided input prior to the conference call that is available in the Agencywide Documents Access and Management System at Accession No. ML22020A179. The licensee input includes additional inspection details using the NRC supplied SG tube inspection discussion points template with the licensee providing responses in color.
Comanche Peak, Unit 2, has four Westinghouse Model D5 SGs, each of which contains 4,570 thermally treated Alloy 600 tubes. Each tube has a nominal outside diameter of 0.750 inches and a nominal wall thickness of 0.043 inches. During SG fabrication, the tube ends were hydraulically expanded over the full depth of the tubesheet. The vertical sections of the tubes are supported on the hot-leg (HL) and cold-leg (CL) sides by horizonal stainless steel tube support plates (TSPs) with quatrefoil holes. The CL size also has a stainless steel flow distribution baffle and stainless steel preheater baffle plates, all with drilled holes. Some of the tubes in each SG were hydraulically expanded at selected preheater baffle plates to reduce tube vibration. Two sets of chrome-plated Alloy 600 anti-vibration bars support the U-bend section of the tubes.
Information provided by the licensee during the November 4, 2021, conference call is summarized below:
At the time of the call, eddy current tube inspection had been completed in SG 1 and SG 4 and was approximately 50 percent complete in SG 2 and SG 3. The remaining eddy current inspection was expected to be complete about 2 days after the call.
At the time of the call the following cases of degradation had been identified:
o A new degradation mechanism for Comanche Peak, Unit 2, axial outside diameter stress corrosion cracking (ODSCC) at a free span ding, was detected in one tube, in SG 1, row 1, column 69 (R1C69). The indication was located on the HL, approximately 18 inches above TSP H3 in the tubing free span. The maximum depth and length of the indication were sized at 62 percent through-wall (TW) and 0.19 inches long, respectively. Based on the screening criteria in industry guidelines, in situ pressure testing was not required.
The licensee discussed the results from historical review of the R1C69 tube inspection data with the NRC staff. The earliest change in the indication signal was in 2008, but the signal change did not meet reporting thresholds. In 2011, a rotating pancake coil (RPC) inspection revealed a signal that one of the two initial inspectors called a single axial indication, but the signal was dismissed during the resolution Enclosure
process. In 2014, a bobbin probe inspection showed a signal that was called as a distorted dent indication (DNI), but no RPC inspection was performed. In 2017, two inspectors called the indication from a bobbin inspection a DNI and called the indication from a RPC inspection a single volumetric indication; however, the called indication was dismissed during the resolution process. The NRC staff stated that the use of a probe with enhanced detection capability at the next inspection, for indications that were previously called crack-like until the resolution process, may result in earlier crack detection in a similar scenario. The licensee indicated it will consider if a change should be made to its inspection program.
o 369 anti-vibration bar wear indications (210 in SG 1, 50 in SG 2, 65 in SG 3, and 44 in SG 4), with a maximum depth of 39 percent TW.
o 21 TSP wear indications (9 in SG 1, 5 in SG 2, 2 in SG 3, and 5 in SG 4), with a maximum depth of 17 percent TW.
o 11 new and legacy foreign object wear indications (1 in SG 2, 1 in SG 3, and 9 in SG 4), with a maximum depth of 34 percent TW.
Condition monitoring limits were met for all indications at the time of the call.
Three tubes had been identified for plugging at the time of the call. One was the tube with axial ODSCC at a free span ding. The other two tubes being plugged were the last potential high-stress tubes still in service among the low-radius U-bend tubes (rows 1-9).
No new tubes with potentially high stress have been identified since the initial screening in 2003. As stated above, the licensee plans to plug two potentially high-stress low-row tubes this outage, which would leave 62 potential high-stress tubes (i.e., -2 sigma) in service, in rows 10 or higher.
No indications of primary-to-secondary leakage were observed during operation since the previous refueling outage, no exceptions were taken to the industry guidelines, and no in situ pressure tests, tube pulls, or secondary-side pressure tests were planned or performed during the current outage.
Eddy current inspections were performed of the tubes in all four SGs. The inspection scope included:
o Full-length bobbin probe examination of all in-service tubes, except for the U-bend section in rows 1 and 2.
o +Point' (rotating probe) inspection of the U-bend section of tubes in rows 1 and 2.
o +Point' probe inspection of all tubes from 3 inches above, to 15 inches below, the top of the tubesheet (TTS) on the HL. (Inspection is not required lower than 14.01 inches below the TTS.)
o +Point' probe inspection of all HL and CL TSP locations and from 3 inches above to 3 inches below the CL TTS in the potential high-stress tubes.
o +Point' probe inspection of all dents/dings with bobbin probe voltage greater than 5.0 volts on the HL and U-bend region, all dents/dings greater than 2.0 volts at and below TSP C7, and dents greater than 2.0 volts at TSP H3.
o +Point' probe inspection of legacy loose parts and foreign objects and possible loose part bobbin probe signals.
o Various other special interest examinations.
To detect loose parts and foreign objects, the licensee performed visual inspection of the TTS, preheater, and water box, and sludge lancing and TTS foreign object search and retrieval in all SGs. Upper bundle visual inspection was performed in SG 3, and preheater baffle plate C2 visual inspection was performed in SG 4. Scale profiling was being performed for all SGs and would be completed after the outage.
New foreign object wear was detected in two tubes in SG 4, with maximum depths of 34 and 15 percent TW. The wear was attributed to a wire mesh that was removed from between the tubes, two inches above baffle plate C2.
The licensee informed the NRC staff that four screws had been dropped in the SG bowls during the maintenance activities of the current outage. At the time of the call, one screw had been retrieved and the licensee was making plans for search and retrieval of the others.
The NRC staff did not identify any issues that required followup action at this time. However, the NRC staff requested notification if the licensee found any unexpected or unusual results in the remaining inspections.
ML22020A178 *by email OFFICE NRR/DORL/LPL4/PM NRR/DORL/LPL4/LA* NRR/DNRL/NCSG/BC*
NAME DGalvin PBlechman SBloom DATE 1/26/2022 1/24/2022 11/15/2021 OFFICE NRR/DORL/LPL4/BC* NRR/DORL/LPL4/PM*
NAME JDixon-Herrity DGalvin DATE 1/31/2022 1/31/2022
