Letter Sequence Response to RAI |
---|
EPID:L-2020-LRO-0084, (VCSNS) Unit 1 - Special Report (Spr) 2020002 - Steam Generator Tube Inspection Report (Approved, Closed) |
|
MONTHYEARML20296A6922020-10-20020 October 2020 (VCSNS) Unit 1 - Special Report (Spr) 2020002 - Steam Generator Tube Inspection Report Project stage: Request ML20349A3262020-12-14014 December 2020 (Vcsns), Unit 1 - Response to NRC Request for Additional Information Regarding RF-24 Steam Generator Tube Inspection Report Project stage: Response to RAI ML21131A0402021-05-11011 May 2021 NRR E-mail Capture - V.C. Summer, Unit 1 - Final RAI for the Spring 2020 RFO Sgtir Review Project stage: RAI ML21154A1802021-06-0303 June 2021 Response to NRC Request for Additional Information Regarding RGF-25 Steam Generator Tube Inspection Report Project stage: Response to RAI ML21180A4052021-06-29029 June 2021 (Vcsns), Unit 1 - Supplement to Request for Additional Information Regarding RF-25 Stem Generator Tube Inspection Report Project stage: Supplement ML21201A3262021-08-0202 August 2021 Review of Steam Generator Inservice Inspection Report End of the Twenty Fifth Refueling Outage Project stage: Approval 2021-05-11
[Table View] |
|
---|
Category:Letter
MONTHYEARML24038A0322024-02-0707 February 2024 (Vcsns), Unit 1, 10 CFR 21 Report - Emergency Diesel Generator Flash Contactor Relay IR 05000395/20230042024-01-31031 January 2024 Integrated Inspection Report 05000395/2023004 ML24022A1582024-01-22022 January 2024 (Vcsns), Unit 1 - Reply to a Notice of Violation: EA-23-093 ML24022A1202024-01-22022 January 2024 Notification of Target Set Inspection and Request for Information (NRC Inspection Report 05000395/2024403) ML24018A0112024-01-18018 January 2024 CFR 21 Report Emergency Diesel Generator Fuel Oil Piping IR 05000395/20240112024-01-17017 January 2024 Notification of VC Summer Station Comprehensive Engineering Team Inspection - U.S. Nuclear Regulatory Commission Inspection Report 05000395/2024011 ML23361A1042023-12-21021 December 2023 Inservice Testing Program for Pumps and Valves Fifth Interval Update and Associated Relief and Alternative Requests IR 05000395/20230912023-12-21021 December 2023 Final Significance Determination of a White Finding and Notice of Violation and Assessment Followup Letternrc Inspection Report 05000395/2023091 ML23354A1802023-12-20020 December 2023 301 Examination Report with Cover Letter ML23347A0492023-12-12012 December 2023 Technical Specification Bases Changes Updated Through November 2023 ML23334A2462023-11-30030 November 2023 Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation ML23334A2372023-11-30030 November 2023 (Vvsns), Unit 1 - Annual Commitment Change Summary Report ML23332A1942023-11-28028 November 2023 (Vcsns), Unit 1, Correction of Typographical Error in License Amendment Request - Inverter Allowed Outage Time (AOT) Extension ML23317A2242023-11-0909 November 2023 (Vcsns), Unit 1 - License Amendment Request - Inverter Allowed Outage Time (AOT) Extension ML23289A1172023-11-0303 November 2023 Tribal Request for Scoping Comments Concerning the Environmental Review of the V.C. Summer SLRA ML23289A1152023-11-0303 November 2023 Ltr to R. Nelson - Request for Scoping Comments Concerning the Environmental Review of the V.C. Summer SLRA ML23289A1162023-11-0303 November 2023 Ltr to W. Emerson - Request for Scoping Comments Concerning the Environmental Review of the V.C. Summer SLRA IR 05000395/20234032023-11-0101 November 2023 Material Control and Accounting Program Inspection Report 05000395/2023403 Cover IR 05000395/20230032023-11-0101 November 2023 Integrated Inspection Report 05000395/2023003 ML23284A1792023-10-16016 October 2023 Subsequent License Renewal Application Online Reference Portal ML23275A0142023-10-11011 October 2023 SLRA - Acceptance and Opportunity for Hearing - Letter ML23284A1662023-10-10010 October 2023 (Vcsns), Unit 1 - Request for Regulatory Conference; (EA-23-093) IR 05000395/20230902023-10-0404 October 2023 NRC Inspection Report 05000395/2023090 and Preliminary Yellow Finding and Apparent Violation IR 05000395/20230112023-09-27027 September 2023 Focused Engineering Inspection Report 05000395/2023011 ML23250A3112023-09-20020 September 2023 Request to Revise Reactor Vessel Material Surveillance Capsule Withdrawal Schedules ML23244A2352023-09-18018 September 2023 Request to Use a Subsequent Edition of the ASME Code, Section XI ML23230A0012023-09-15015 September 2023 Request to Use a Provision of a Previous Edition of the ASME Boiler and Pressure Vessel Code, Section XI, for Non-Destructive Examinations ML23235A0432023-09-0505 September 2023 Receipt and Availability of the Subsequent License Renewal Application IR 05000395/20234012023-08-30030 August 2023 Security Baseline Inspection Report 05000395/2023401 ML23242A1192023-08-29029 August 2023 (Vcsns), Unit 1 - Inservice Inspection (ISI) Owner'S Activity Report (OAR) for Refueling Outage 27 ML23243B0362023-08-25025 August 2023 Request for FEMA Consultation on the Dominion Energy Proposal to Consolidate the Emergency Operations Facility for the Virgil C. Summer Nuclear Station Unit 1 IR 05000395/20230052023-08-23023 August 2023 Updated Inspection Plan for Virgil C. Summer Nuclear Station (Report 05000395 2023005) ML23233A1752023-08-17017 August 2023 Application for Subsequent Renewed Operating License IR 05000395/20230022023-08-14014 August 2023 Integrated Inspection Report - Integrated Inspection Report 05000395/2023002 and Apparent Violation IR 05000395/20230102023-08-12012 August 2023 Biennial Problem Identification and Resolution Inspection Report 05000395/2023010 ML23207A1102023-07-26026 July 2023 NRC Regulatory Issues Summary 2023-01 Preparation and Scheduling of Operator Licensing Examinations IR 05000395/20234412023-07-17017 July 2023 95001 Supplemental Inspection Report 05000395/2023441 and Follow Up Assessment Letter ML23190A0012023-07-0909 July 2023 Special Report 2023-003 Inoperable Radiation Monitoring Instrumentation Channel ML23187A5092023-07-0606 July 2023 Request for Federal Emergency Management Agency Consultation on the Dominion Energy Proposal to Consolidate the Emergency Operations Facility for the Virgil C. Summer Nuclear Station Unit 1 ML23178A1682023-06-26026 June 2023 2022 Annual Report of Emergency Core Cooling System (ECCS) Model Changes Pursuant to the Requirements of 10 CFR 50.46 ML23173A1052023-06-22022 June 2023 Special Report 2023-002 Inoperable Loose-Part Monitoring System Channel ML23163A2352023-06-12012 June 2023 Request to Use a Later Edition of the ASME Boiler and Pressure Vessel Code, Section XI, for the SPS Sixth Inservice Inspection (Isi) Intervals and VCSNS Fifth ISI Interval ML23159A2332023-06-0808 June 2023 License Amendment Request - Emergency Response Organization Augmentation Time Change, Emergency Operations Facility Relocation and Other Emergency Plan Changes ML23156A3092023-06-0505 June 2023 Requalification Program Inspection Virgil C. Summer Nuclear Station Unit 1 - 05000395/2023003 2024-02-07
[Table view] Category:Response to Request for Additional Information (RAI)
MONTHYEARML22353A5462022-12-19019 December 2022 (Vcsns), Unit 1 - Alternative Request to Defer ASME Code Section XI Inservice Inspection Examinations for Pressurizer and Steam Generator Pressure-Retaining Welds and Full Penetration Welded Nozzles Response to Request ML22300A2202022-10-27027 October 2022 (VCSNS) Unit 1, Alternative Request Rr-4-26 Application for Alternative Request - Extension of Steam Generator Primary Inlet Nozzle Dissimilar Metal Weld Inspection Interval (Volumetric Examination) RAI ML22020A2262022-01-20020 January 2022 Response to Request for Additional Information to License Amendment Request LAR-20-203 Application for Technical Specification Change Regarding Risk-Informed Justification for the Relocation of Specific Surveillance Frequency ML21180A4052021-06-29029 June 2021 (Vcsns), Unit 1 - Supplement to Request for Additional Information Regarding RF-25 Stem Generator Tube Inspection Report ML21168A2612021-06-17017 June 2021 (Vcsns), Unit 1 - NRC Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-water Reactors - Final Supplemental Response ML21154A1802021-06-0303 June 2021 Response to NRC Request for Additional Information Regarding RGF-25 Steam Generator Tube Inspection Report ML21007A3232021-01-0707 January 2021 License Amendment Request LAR-20-142 Request for Technical Specification Change Technical Specification 3.6.4, Containment Isolation Valves Response to Request for Additional Information (RAI) ML21007A3402021-01-0707 January 2021 (Vcsns), Unit 1 - License Amendment Request LAR-20-176 Update of Analytical Method to the Core Operating Limits Report with the Full Spectrum Loss of Coolant Accident Approach - Response to Request for Additional Info ML20349A3262020-12-14014 December 2020 (Vcsns), Unit 1 - Response to NRC Request for Additional Information Regarding RF-24 Steam Generator Tube Inspection Report ML19282E2612019-10-0909 October 2019 Response to Follow-Up Question to PRA RAI 03, License Amendment Request - LAR-16-01490 NFPA 805 Program Revisions ML19224B1152019-08-12012 August 2019 Response to NRC Follow-Up Question PRA RAI 03, License Amendment Request - LAR-16-01490 NFPA 805 Program Revisions ML19119A3652019-04-29029 April 2019 (Vcsns), Unit 1 - License Amendment Request - LAR-16-01490, NFPA 805 Program Revisions: Response to Request for Additional Information ML19071A3572019-03-11011 March 2019 Request for License Amendment to Virgil C. Summer Nuclear Station Technical Specification 3.8.2., D.C. Sources - Operating, Surveillance Requirements 4.8.2.1.b.2 and 4.8.2.1.c.3 - Request for Additional Information RC-18-0116, (Vcsns), Unit 1 - Request for a One-Time Extension to the Surveillance Frequency 4.4.4.6 of the Core Exit Temperature Instrumentation - Response to Request for Additional Information2018-09-11011 September 2018 (Vcsns), Unit 1 - Request for a One-Time Extension to the Surveillance Frequency 4.4.4.6 of the Core Exit Temperature Instrumentation - Response to Request for Additional Information RC-18-0100, (Vcsns), Unit 1 - Technical Specification Change Request for the Revision of the Surveillance Frequency of the Turbine Trip Functional Unit: Response to Request for Additional Information2018-08-22022 August 2018 (Vcsns), Unit 1 - Technical Specification Change Request for the Revision of the Surveillance Frequency of the Turbine Trip Functional Unit: Response to Request for Additional Information RC-18-0090, (Vcsns), Unit 1 - Relief Request RR-4-16, Request for Alternative to Implement Code Case N-513-4, Evaluation Criteria for Temporary Acceptance of Flaws in Moderate Energy Class 2 or 3 Piping Response to Request...2018-07-12012 July 2018 (Vcsns), Unit 1 - Relief Request RR-4-16, Request for Alternative to Implement Code Case N-513-4, Evaluation Criteria for Temporary Acceptance of Flaws in Moderate Energy Class 2 or 3 Piping Response to Request... RC-18-0084, Virgil C Summer Nuclear Station (Vcsns), Unit 1 - Relief Request RR-4-15, Request for Alternative to Implement Code Case N-513-4, Evaluation Criteria for Temporary Acceptance of Laws in Moderate Energy Class 2 or 3 Piping Response to Requ2018-07-0303 July 2018 Virgil C Summer Nuclear Station (Vcsns), Unit 1 - Relief Request RR-4-15, Request for Alternative to Implement Code Case N-513-4, Evaluation Criteria for Temporary Acceptance of Laws in Moderate Energy Class 2 or 3 Piping Response to Reques RC-18-0046, License Amendment Request LAR-14-01541 Integrated Leak Rate Test Peak Calculated Containment Internal Pressure Change Request for Additional Information2018-04-19019 April 2018 License Amendment Request LAR-14-01541 Integrated Leak Rate Test Peak Calculated Containment Internal Pressure Change Request for Additional Information RC-18-0036, (Vcsns), Unit 1 - Relief Request RR-4-13, Use of a Risk-Informed Process as an Alternative for the Selection of Class 1 and Class 2 Piping Welds - Response to Request for Additional Information2018-04-0202 April 2018 (Vcsns), Unit 1 - Relief Request RR-4-13, Use of a Risk-Informed Process as an Alternative for the Selection of Class 1 and Class 2 Piping Welds - Response to Request for Additional Information RC-17-0134, Response to Request for Supplemental Information, License Amendment Request - LAR-15-01424; Implementation of WCAP-15376-P-A, Revision 12017-09-27027 September 2017 Response to Request for Supplemental Information, License Amendment Request - LAR-15-01424; Implementation of WCAP-15376-P-A, Revision 1 RC-17-0093, License Amendment Request - LAR-15-01424 Implementation of WCAP-15376-P-A, Revision 1 - Risk-Informed Assessment of the RTS and ESFAS Surveillance Test Intervals and Reactor Trip Breaker Test and Completion Times, Response To.2017-07-0606 July 2017 License Amendment Request - LAR-15-01424 Implementation of WCAP-15376-P-A, Revision 1 - Risk-Informed Assessment of the RTS and ESFAS Surveillance Test Intervals and Reactor Trip Breaker Test and Completion Times, Response To. RC-17-0088, Implementation of WCAP-15376-P-A, Revision 1 - Risk-Informed Assessment of the RTS and ESFAS Surveillance Test Intervals and Reactor Trip Breaker Test and Completion Times - Response to Request for Additional Information2017-06-22022 June 2017 Implementation of WCAP-15376-P-A, Revision 1 - Risk-Informed Assessment of the RTS and ESFAS Surveillance Test Intervals and Reactor Trip Breaker Test and Completion Times - Response to Request for Additional Information RC-17-0032, Spent Fuel Evaluation Supplemental Report, Response to NRC for Information Pursuant to 10 CFR 50.54(f) Regarding Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-Ichi Accident2017-03-30030 March 2017 Spent Fuel Evaluation Supplemental Report, Response to NRC for Information Pursuant to 10 CFR 50.54(f) Regarding Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-Ichi Accident ML17087A1512017-03-28028 March 2017 Response to Request for Additional Information on VC Summer Sfpli RC-17-0019, Response to Request for Additional Information Regarding License Amendment Request LAR-15-01424, Implementation of WCAP-15376-P-A, Revision 12017-02-0606 February 2017 Response to Request for Additional Information Regarding License Amendment Request LAR-15-01424, Implementation of WCAP-15376-P-A, Revision 1 RC-16-0147, VC Summer Nuclear Station, Unit 1, Response to Generic Letter 2016-01, Monitoring of Neutron-Absorbing Materials in Spent Fuel Pools Pursuant to Title 10 9f the Code of Federal Regulations 05.54(f)2016-11-0303 November 2016 VC Summer Nuclear Station, Unit 1, Response to Generic Letter 2016-01, Monitoring of Neutron-Absorbing Materials in Spent Fuel Pools Pursuant to Title 10 9f the Code of Federal Regulations 05.54(f) ML16235A2422016-08-18018 August 2016 Response to Request for Information for Triennial Fire Protection Baseline Inspection RC-16-0091, Response to Request for Additional Information on Relief Request RR-III-12 Proposed Alternative Inspection Requirements for Piping Welds2016-06-0202 June 2016 Response to Request for Additional Information on Relief Request RR-III-12 Proposed Alternative Inspection Requirements for Piping Welds RC-16-0077, Relief Request RR-III-12, Proposed Alternative Inspection Requirements for Piping Welds - Response to Request for Additional Information2016-05-0606 May 2016 Relief Request RR-III-12, Proposed Alternative Inspection Requirements for Piping Welds - Response to Request for Additional Information RC-16-0046, Response to Request for Additional Information on Relief Request RR-III-2, Proposed Alternative Inspection Requirements for Piping Welds2016-03-18018 March 2016 Response to Request for Additional Information on Relief Request RR-III-2, Proposed Alternative Inspection Requirements for Piping Welds RC-16-0036, License Amendment Request - LAR-15-01424 - Implementation of WCAP-15376-P-A, Revision 1, Response to Request for Supplemental Information2016-03-0707 March 2016 License Amendment Request - LAR-15-01424 - Implementation of WCAP-15376-P-A, Revision 1, Response to Request for Supplemental Information RC-16-0031, License Amendment Request - LAR-12-04269, License Basis Changes in Steam Generator Tube Rupture Analysis Supplement Response2016-03-0404 March 2016 License Amendment Request - LAR-12-04269, License Basis Changes in Steam Generator Tube Rupture Analysis Supplement Response RC-16-0039, Exigent License Amendment Request - LAR (16-00848), Technical Specification Change Request for Emergency Feedwater System Limiting Condition for Operation 3.7.1.2 Action B - Response to Request for Additional..2016-03-0303 March 2016 Exigent License Amendment Request - LAR (16-00848), Technical Specification Change Request for Emergency Feedwater System Limiting Condition for Operation 3.7.1.2 Action B - Response to Request for Additional.. RC-16-0001, V.C. Summer, Report of Full Compliance with March 12, 2012, Commission Order Modifying Licenses with Regard to Reliable Spent Fuel Pool Instrumentation (Order EA-12-051) and Responses to Requests for Additional Information2016-01-22022 January 2016 V.C. Summer, Report of Full Compliance with March 12, 2012, Commission Order Modifying Licenses with Regard to Reliable Spent Fuel Pool Instrumentation (Order EA-12-051) and Responses to Requests for Additional Information RC-16-0006, Response to Request for Additional Information to License Amendment Request - LAR-12-04269, License Basis Changes in Steam Generator Tube Rupture Analysis2016-01-14014 January 2016 Response to Request for Additional Information to License Amendment Request - LAR-12-04269, License Basis Changes in Steam Generator Tube Rupture Analysis RC-15-0186, Response to Request for Information (NRC Inspection Report No. 05000395/2015404)2015-11-11011 November 2015 Response to Request for Information (NRC Inspection Report No. 05000395/2015404) IR 05000395/20154042015-11-11011 November 2015 V.C. Summer, Unit 1 - Response to Request for Information (NRC Inspection Report No. 05000395/2015404) RC-15-0160, Response to Request for Information (NRC Inspection Report No. 05000395/2015404)2015-09-25025 September 2015 Response to Request for Information (NRC Inspection Report No. 05000395/2015404) ML15310A0762015-09-21021 September 2015 Response to Request for Information to Support the Cyber Security Inspection RC-15-0142, License Amendment Request, LAR 12-04269, License Basis Changes in Steam Generator Tube Rupture Analysis, Response to Request for Additional Information2015-09-10010 September 2015 License Amendment Request, LAR 12-04269, License Basis Changes in Steam Generator Tube Rupture Analysis, Response to Request for Additional Information RC-15-0116, Response to NRC Request for Information Baseline Radiation Safety Inspection2015-07-13013 July 2015 Response to NRC Request for Information Baseline Radiation Safety Inspection 2022-12-19
[Table view] |
Text
V.C. Summer Nuclear Station Bradham Blvd & Hwy 215, Jenkinsville, SC 29065
~ Dominion Mailin g Address: ~ Energy P.O. Box 88, Jenki n sville, SC 29065 Dominion Energy. co m December 14, 2020 Document Control Desk Serial No.20-409 U.S. Nuclear Regulatory Commission VCS UC/BAB/Rev 0 Washington, DC 20555 Docket No. 50-395 License No. NPF-12 DOMINION ENERGY SOUTH CAROLINA (DESC)
VIRGIL C. SUMMER NUCLEAR STATION (VCSNS) UNIT 1 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING RF-24 STEAM GENERATOR TUBE INSPECTION REPORT References : 1. DESC Letter, "Special Report (SPR) 2019-002 - Steam Generator Tube Inspection Report," dated May 14, 2019 (ADAMS Accession No. ML19134A372)
- 2. E-mail from NRC Senior Project Manager, Vaughn Thomas, "Summer, Unit 1-Final RAls for the SG Tube Inspection Report Review," dated November 16, 2020 (ADAMS Accession No. ML20321A211)
In Reference 1, DESC submitted a Technical Specification required report related to steam generator inspections performed during the Virgil C. Summer Unit 1 Twenty-Fourth Refueling Outage. In Reference 2, the NRC Staff provided a request for additional information (RAI) regarding this report. The enclosure to this letter provides the DESC responses to the RAI.
If you have any questions or require additional information, please contact Mr. Michael Moore at (803) 345-4752.
Sincerely, ~
~~pard Site Vice President V.C . Summer Nuclear Station Commitments contained in this letter: None
Enclosure:
Response to NRC Request for Additional Information cc: G. J. Lindamood - Santee Cooper L. Dudes - NRC Region II V. Thomas - NRC Project Mgr.
NRC Resident Inspector
Serial No.20-409 Docket No.: 50-395 Enclosure Response to NRC Request for Additional Information Virgil C. Summer Nuclear Station (VCSNS) Unit 1 Dominion Energy South Carolina, Inc. (DESC)
Serial No.20-409 Docket No.: 50-395 Enclosure - RAI Response: Page 1 of 3 DESC RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING VCSNS Unit 1 RF-24 STEAM GENERATOR TUBE INSPECTION REPORT NRC Request for Additional Information:
- 1. Please discuss if there were any anomalies noted during the primary side visual inspections performed on each SG.
- 2. The NRG staff has the following questions regarding the secondary side inspections performed on each SG;
- a. Please discuss if there were any anomalies noted during the secondary side inspections performed on each SG.
- b. Section 3.4, "Foreign Object Wear," of the fa/12018 SG tube inspection report states that two foreign object wear indications were identified in tubes Row 25, Column 72 (R25C72) and R11 0C77 in SG A, and two foreign object wear indications were identified in tubes R91C88 and R92C87 in SG B. Please discuss whether the foreign objects were still present at the time of the inspection and if they were removed from the SGs.
- c. Section 6.0, "Tubes Plugged during the Inspection Outage," of the fa/12018 SG tube inspection report states that a total of 10 tubes were plugged; 3 plugged due to foreign object wear and 7 plugged due to possible loose parts (PLPs). Please confirm whether the PLPs were newly identified during RFO24, how many total PLPs there were in the seven tubes, and describe any additional actions taken to further evaluate these PLPs.
DESC Response to RAI 1:
As noted in the RF-24 Condition Monitoring and Final Operational Assessment, in response to NSAL 12-1, Revision 1, the visual inspection of the SG channel head bowl included inspections of the entire channel head internal surfaces; specifically the entire tubesheet, cladding, divider plate, and associated welds/components. This visual inspection confirmed that the channel head bowl in each SG was in satisfactory condition and identified no signs of degradation, rust, deformation, or abnormal conditions.
DESC Response to RAI 2a:
As noted in Special Report (SPR) 2019-002 - Steam Generator Tube Inspection Report, secondary side inspections were performed during RF-24 for the top of the tubesheet, top support plate, and stream drum in all three steam generators. Inspection results from the RF-24 Condition Monitoring and Final Operational Assessment are discussed below.
Top of the Tubesheet (TTS)
Post sludge lancing TTS visual inspections included inspections performed from the periphery (annulus between the tube bundle and shroud ID) and the no-tube lane.
Additionally, inner bundle passes were performed across both the hot leg and cold legs to pass through the kidney region of each steam generator. Other than the foreign object
Serial No.20-409 Docket No.: 50-395 Enclosure - RAI Response: Page 2 of 3 related findings discussed below, no abnormal conditions were identified during the TTS inspections.
Top (9th ) Tube Support Plate (TSP)
Visual inspections of the top (9 th ) TSP along the no-tube lane region were performed in each SG. The inspections focused on the general condition of the TSP including the general condition of sludge/fouling of the no-tube lane, TSP ligaments, and low row U-bends. The inspection also covered webbing or bridging between the tubes/broaches, tube-to-tube bridging and blocked/partially blocked flow/broached holes. Inner bundle passes (hot leg and cold leg), at right angles to the 9th support no-tube lane, were also performed to the extent possible. These visual inspections identified no conditions adverse to quality, with the exception of heavy deposit formations. Tube denting was identified in SG Cat the 09H Top Support Plate which could be related to the heavy deposit formation.
The deposit accumulation identified in RF-24 (Fall 2018) was one of the drivers for the SG chemical cleaning performed in RF-25 (Spring 2020).
Steam Drum All steam drum components including the feedring and associated spray-nozzles (spray cans), various manways/access hatches, primary and secondary separators, sludge collectors, level tap nozzles, ladders, and attachments were inspected in each SG during RF-24. Additionally, the outlet nozzle flow limiting venturi was also inspected in SG A.
The purpose of these inspections was to identify evidence of corrosion, erosion, chemical deposition, foreign material, or other degradation, and conditions not commensurate with design. No conditions adverse to quality were identified. However, foreign material was found inside the feedring spray-nozzles (spray cans) in each steam generator. Foreign material determined to be a threat to tube integrity was removed from the feedrings and spray-nozzles.
DESC Response to RAI 2b:
The RF-24 (Fall 2018) steam generator inspections found no foreign objects present at the foreign object wear locations in SG A at tube R25-C72, SG Bat tube R91-C88, and SG Bat tube R92-C87. Gasket material and a round sludge ball were identified at the wear location in SG A at tube R 11 0-C77. The gasket material was identified to be stuck in the tube broach on one end at tube R110-C77 with the other end elevated between (and touching) tubes R109-C78 and R108-C77. As such, tubes R110-C77, R108-C77, and R109-C78 were preventively plugged. During RF-25 (Spring 2020), the gasket material was visually confirmed at the same as-left location from RF-24. The sludge ball could not be removed in RF-24 but was considered loose or free to move and not a threat to tube integrity.
DESC Response to RAI 2c:
From the RF-24 Condition Monitoring and Final Operational Assessment, there were seven (7) tubes plugged due to PLPs. Five (5) of these tubes had new PLP single indications whose locations were not accessible by secondary side inspection/foreign object search and retrieval (SSI/FOSAR). These indications were at locations on the
Serial No.20-409 Docket No.: 50-395 Enclosure - RAI Response: Page 3 of 3 01 C or 01 H Tube Support Plate that do not have inspection ports. Although these five locations could not be visually inspected, based on the locations, it is surmised that the single PLP indications in SG A at tube R111-C62 and tube R113-C62 are for the same foreign object. This is also the case for the PLP indications in SG C at tube R11 0-C91 and tube R 111-C92. The final tube plugged due to inaccessible PLPs at the 01 C or 01 H Tube Support Plate was in SG A at tube R95-C34. The remaining two (2) PLPs were associated with confirmed foreign objects that could not be removed (a piece of flexitallic gasket and a sludge ball located on the hot leg side of the baffle plate). Tubes R 108-C77 and R109-C78 (along with tube R110-C77 which was plugged due to loose part wear) were plugged to bound the piece of flexitallic gasket.
The RF-24 Condition Monitoring and Final Operational Assessment determined that with the exception of the flexitallic gasket and sludge ball in SG A at tube R11 0-C77, no known loose foreign objects were returned to service in RF-24. The Condition Monitoring and Final Operational Assessment concluded the following with regard to foreign objects:
- The foreign object wear indications observed during RF-24 did not exceed the condition monitoring limits.
- Reasonable assurance is provided that the foreign objects being returned to service at RF-24 should not experience foreign object wear to the point of violating structural and/or leakage integrity.
- Reasonable assurance is provided that any potential foreign objects that could enter the steam generators over cycles 25, 26, and 27, should not experience foreign object wear to the point of violating structural and/or leakage integrity.
It should be noted that no new foreign object wear indications were identified in RF-25.
Foreign object wear was detected in SG B; however, this was a repeat wear indication with no increase in depth, which was expected since no part was found at the affected tube location during RF-24.