CNL-21-040, Supplement to Expedited Application for Approval to Use a Growth Rate Temperature Adjustment When Implementing the Generic Letter 95-05 Analysis for the (WBN TS-391-21-002)

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Supplement to Expedited Application for Approval to Use a Growth Rate Temperature Adjustment When Implementing the Generic Letter 95-05 Analysis for the (WBN TS-391-21-002)
ML21082A118
Person / Time
Site: Watts Bar Tennessee Valley Authority icon.png
Issue date: 03/23/2021
From: Polickoski J
Tennessee Valley Authority
To:
Document Control Desk, Office of Nuclear Reactor Regulation
Shared Package
ML21082A117 List:
References
CNL-21-040, EPID L-2021-LLA-0026, GL-95-05, WBN TS-391-21-002 SG-CDMP-20-23-NP, Rev 2
Download: ML21082A118 (98)
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Text

Proprietary Information Withhold Under 10 CFR § 2.390 This letter is decontrolled when separated from Enclosure 1 TENNESSEE 1\14 VALLEY AUTHORITY 1101 Market Street, Chattanooga, Tennessee 37402 CNL-21-040 March 23, 2021 10 CFR 50.90 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001 Watts Bar Nuclear Plant Unit 2 Facility Operating License No. NPF-96 NRC Docket No. 50-391

Subject:

Supplement to Expedited Application for Approval to Use a Growth Rate Temperature Adjustment When Implementing the Generic Letter 95-05 Analysis for the Watts Bar Nuclear Plant Unit 2 Steam Generators (WBN TS-391-21-002) (EPID L-2021-LLA-0026)

Reference:

TVA letter to NRC, CNL-21-011, Expedited Application for Approval to Use a Growth Rate Temperature Adjustment When Implementing the Generic Letter 95-05 Analysis for the Watts Bar Nuclear Plant (WBN), Unit 2 Steam Generators (WBN TS-391-21-002), dated February 25, 2021 (ML21056A623 and ML21056A624)

In the referenced letter, Tennessee Valley Authority (TVA) submitted a request for an amendment to Facility Operating License No. NPF-96 for the Watts Bar Nuclear Plant (WBN),

Unit 2 to revise the WBN dual-unit Updated Final Safety Analysis Report (UFSAR) to apply a temperature adjustment to the growth rate calculation used to determine the end-of-cycle (EOC) distribution of indications of axial outside diameter stress corrosion cracking at tube support plates.

To assist the Nuclear Regulatory Commission (NRC) in their review of this license amendment request, Enclosure 1 to this letter contains Westinghouse Electric Company LLC (Westinghouse) Report, SG-CDMP-20-23-P, Revision 2, Watts Bar U2R3 Steam Generator Condition Monitoring and Final Operational Assessment, which is the operational assessment for the steam generator inspection conducted during the WBN Unit 2 Cycle 3 refueling outage (U2R3). contains information that Westinghouse considers to be proprietary in nature pursuant to 10 CFR 2.390, "Public inspections, exemptions, requests for withholding,"

paragraph (a)(4). Enclosure 2 contains a non-proprietary version of Enclosure 1. Enclosure 3 provides the Westinghouse Application for Withholding Proprietary Information from Public Disclosure CAW-21-5162 affidavit supporting this proprietary withholding request. The affidavit Proprietary Information Withhold Under 10 CFR § 2.390 This letter is decontrolled when separated from Enclosure 1

Proprietary Information Withhold Under 10 CFR § 2.390 This letter is decontrolled when separated from Enclosure 1 U.S. Nuclear Regulatory Commission CNL-21-040 Page 2 March 23, 2021 sets forth the basis on which the information may be withheld from public disclosure by the NRC and addresses with specificity the considerations listed in paragraph (b)(4) of Section 2.390.

Accordingly, TVA requests that the information, which is proprietary to Westinghouse, be withheld from public disclosure in accordance with 10 CFR Section 2.390. Correspondence with respect to the copyright or proprietary aspects of the items listed above or the supporting Westinghouse affidavit should reference CAW-21-5162 and should be addressed to Zachary S. Harper, Manager, Licensing Engineering, Westinghouse Electric Company, 1000 Westinghouse Drive, Suite 165, Cranberry Township, Pennsylvania 16066.

This letter does not change the no significant hazard considerations or the environmental considerations contained in the referenced letter. Additionally, in accordance with 10 CFR 50.91(b)(1), TVA is sending a copy of this letter and the enclosure to the Tennessee Department of Environment and Conservation.

There are no new regulatory commitments associated with this submittal. Please address any questions regarding this request to Kimberly D. Hulvey, Senior Manager, Fleet Licensing, at (423) 751-3275.

I declare under penalty of perjury that the foregoing is true and correct. Executed on this 23rd day of March 2021.

Respectfully, James T. Polickoski Director, Nuclear Regulatory Affairs

Enclosures:

1. Westinghouse Report SG-CDMP-20-23-P, Revision 2 (Proprietary)
2. Westinghouse Report SG-CDMP-20-23-NP, Revision 2 (Non-Proprietary)
3. Westinghouse Electric Company LLC Application for Withholding Proprietary Information from Public Disclosure (Affidavit CAW-21-5162) cc (Enclosures):

NRC Regional Administrator - Region II NRC Project Manager - Watts Bar Nuclear Plant NRC Senior Resident Inspector - Watts Bar Nuclear Plant Director, Division of Radiological Health - Tennessee State Department of Environment and Conservation Proprietary Information Withhold Under 10 CFR § 2.390 This letter is decontrolled when separated from Enclosure 1

Proprietary Information Withhold Under 10 CFR § 2.390 Enclosure 1 Westinghouse Report SG-CDMP-20-23-P, Revision 2 (Proprietary)

CNL-21-040 Proprietary Information Withhold Under 10 CFR § 2.390

Enclosure 2 Westinghouse Report SG-CDMP-20-23-NP, Revision 2 (Non-Proprietary)

CNL-21-040

WESTINGHOUSE NON-PROPRIETARY CLASS 3 SG-CDMP-20-23-NP March 2021 Revision 2 Watts Bar U2R3 Steam Generator Condition Monitoring and Final Operational Assessment

@Westinghouse

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 SG-CDMP-20-23-NP Revision 2 Watts Bar U2R3 Steam Generator Condition Monitoring and Final Operational Assessment Prepared for:

Tennessee Valley Authority Authors Name: Signature / Date For Pages Jay R. Smith *Electronically Approved All OSG/RSG Engineering & Chemistry Verifiers Name: Signature / Date For Pages Bradley T. Carpenter *Electronically Approved All Component Design & Management Programs Managers Name: Signature / Date For Pages Michael E. Bradley, Manager *Electronically Approved All Component Design & Management Programs

©2021 Westinghouse Electric Company LLC All Rights Reserved

  • Electronically Approved Records are Authenticated in the Electronic Document Management System SG-CDMP-20-23-NP March 2021 Revision 2 Page 2 of 90
      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Record of Revisions Revision Date Description 0 11/13/2020 Original Issue Revision for final Operational Assessment.

1 02/11/2021 (Note: Change bars are used in the left margins where substantial or technical changes occurred. Change bars are not used for editorial changes such as formatting and minor non-technical corrections.)

Revision to identify proprietary information for redaction.

Changes to text:

a) Table 2 Changed AVB Wear values for SG-1, SG-2 and Total.

b) Table 3 Changed Limiting/Total to 2 for the 20-29% TW line.

c) Table 3 Changed U2R2 Maximum Voltage values from +POINT probe values to bobbin coil values.

d) Section 3.1.4, Third Paragraph - Changed Two DSIs to Three DSI/DSVs.

e) Table 3 SG-3, R27C47 - changed indication code from SAI to MAI.

f) Section 3.2.1, second paragraph - added reference to Table A5-1.

2 See EDMS g) Section 3.2.3, second paragraph - added reference to Table A6-1.

h) Section 3.5, First Paragraph - Added the word tubesheet to the second sentence.

i) Section 4.5 second paragraph - clarified statement regarding low flow regions.

j) Table A5 In various places added redundant values and comments for duplicate tube numbers for clarity. Corrected gap velocity value for tube SG-1 R49C47.

(Note: Change bars are used in the left margins where substantial or technical changes occurred. Change bars are not used for editorial changes such as formatting and minor non-technical corrections.)

Trademark Notes:

+POINT and X-PROBE are trademarks or registered trademarks of Zetec, Inc. Other names may be trademarks of their respective owners.

RTAA and ST MAX are trademarks of Westinghouse Electric Company LL LLC, its affiliates and/or its subsidiaries in the United States of America and may be registered in other countries throughout the world. All rights reserved.

Unauthorized use is strictly prohibited. Other names may be trademarks of their respective owners.

SG-CDMP-20-23-NP March 2021 Revision 2 Page 3 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Table of Contents Executive Summary .......................................................................................................................................... 7 1.0 Introduction ................................................................................................................................... 9 2.0 Watts Bar U2R3 Primary Side Inspection Program .................................................................... 10 2.1 Base Scope Inspection Plan ........................................................................................................ 10 2.2 Inspection Expansion .................................................................................................................. 11 2.3 Inspection Results ....................................................................................................................... 11 2.3.1 Eddy Current Inspection Results................................................................................................. 11 2.3.2 Degradation Mechanism Summary ............................................................................................. 12 2.4 Tube Plugging and Stabilization ................................................................................................. 13 3.0 Condition Monitoring ................................................................................................................. 14 3.1 Existing Degradation Mechanisms ............................................................................................. 14 3.1.1 Volumetric Indications due to Tube Fabrication and Installation (Pre-Service)......................... 14 3.1.2 Mechanical Wear at Anti-Vibration Bars ................................................................................... 16 3.1.3 Mechanical Wear at Tube Support Plates ................................................................................... 18 3.1.4 Axial ODSCC at the Tube Support Plates (95-05 Applicable) ................................................... 20 3.1.5 Axial ODSCC at Tube Support Plates (GL 95-05 Not Applicable) ........................................... 22 3.1.6 Circumferential ODSCC at the Hot Leg Top of Tubesheet ........................................................ 22 3.1.7 Axial ODSCC at Expansion Transition and Sludge Pile ............................................................ 25 3.1.8 Axial PWSCC at Expansion Transition ...................................................................................... 26 3.1.9 Circumferential ODSCC at Freespan Dings ............................................................................... 26 3.1.10 Axial ODSCC at Freespan Dings................................................................................................ 28 3.2 Potential Degradation Mechanisms............................................................................................. 29 3.2.1 Mechanical Wear Due to Foreign Objects .................................................................................. 29 3.2.2 Outer Diameter Pitting of the Tube Material .............................................................................. 29 3.2.3 Tube-to-Tube Contact Wear ....................................................................................................... 30 3.2.4 Axial and Circumferential PWSCC in the U-bends .................................................................... 30 3.2.5 PWSCC at Tube Dents and Dings .............................................................................................. 30 3.2.6 SCC at Tube Bulges and Overexpansions .................................................................................. 31 3.2.7 Axial ODSCC in the Tube Freespan ........................................................................................... 31 3.2.8 SCC at Dents and Dings Coincident with a Manufacturing Burnish Mark ................................ 31 3.3 Resolution for Classification of Indications ................................................................................ 31 3.4 SG Channel Head Primary Side Bowl and Tube Plug Visual Inspections ................................. 32 3.5 Noise Monitoring Summary........................................................................................................ 33 3.6 Secondary Side Activities ........................................................................................................... 35 3.6.1 Top of Tubesheet Cleaning ......................................................................................................... 35 3.6.2 Top of Tubesheet FOSAR........................................................................................................... 36 3.6.3 Upper Steam Drum Inspections .................................................................................................. 36 3.7 Condition Monitoring Conclusions ............................................................................................. 36 4.0 Operational Assessment .............................................................................................................. 37 4.1 Mechanical Wear at AVBs ......................................................................................................... 37 4.2 Mechanical Wear at Tube Support Plates ................................................................................... 38 4.3 Stress Corrosion Cracking .......................................................................................................... 39 4.3.1 Circumferential ODSCC at Tubesheet Expansion Transitions ................................................... 41 4.3.2 Axial ODSCC at Tubesheet Expansion Transitions ................................................................... 46 4.3.3 Axial PWSCC at Expansion Transitions..................................................................................... 48 4.3.4 Axial ODSCC at TSP Intersections Excluded from GL 95-05 ................................................... 50 4.3.5 Circumferential ODSCC at Freespan Dings ............................................................................... 52 4.3.6 Axial ODSCC at Freespan Dings................................................................................................ 54 4.4 Cumulative Effect of Probabilistic Analyses .............................................................................. 57 4.5 SG Secondary Side Foreign Objects ........................................................................................... 58 4.6 Operational Assessment Conclusions ......................................................................................... 59 5.0 References ................................................................................................................................... 60 SG-CDMP-20-23-NP March 2021 Revision 2 Page 4 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 List of Tables Table 2-1. Watts Bar U2R3 SG Eddy Current Inspection - Final Indication Summary ................................... 12 Table 2-2. Watts Bar U2R3 Degradation Mechanism Summary ....................................................................... 13 Table 3-1. Watts Bar Unit 2 VOL Indications from Pre-Service Inspection ..................................................... 15 Table 3-2. Watts Bar U2R3 AVB Wear Indications Summary ......................................................................... 17 Table 3-3. Watts Bar U2R3 AVB Wear Summary ............................................................................................ 17 Table 3-4. Watts Bar U2R3 TSP Wear Indications - All SGs ........................................................................... 19 Table 3-5. Axial ODSCC at TSP and FDB Summary ....................................................................................... 21 Table 3-6. Watts Bar U2R3 Axial ODSCC at TSP Locations Excluded from GL 95-05.................................. 22 Table 3-7. Watts Bar U2R3 Circumferential ODSCC at HTS Bounding Size Parameters ............................... 24 Table 3-8. Watts Bar U2R3 Axial ODSCC at Expansion Transition/Sludge Pile ............................................. 26 Table 3-9. Watts Bar U2R3 Axial PWSCC at Expansion Transition ................................................................ 26 Table 3-10. Watts Bar U2R3 Circumferential ODSCC at Freespan Dings ....................................................... 28 Table 3-11. Watts Bar U2R3 Axial ODSCC at Freespan Dings........................................................................ 29 Table 3-12. Watts Bar U2R3 SG 95th Percentile Bobbin Noise Measurements ............................................... 34 Table 3-13. Watts Bar U2R3 SG Tubesheet Deposit Removal ......................................................................... 35 Table 3-14. Watts Bar U2R3 SG FOSAR Summary ......................................................................................... 36 Table 4-1. Circumferential ODSCC at HTS FBM Simulation Results Summary .............................................. 42 Table 4-2. Axial ODSCC at HTS FBM Simulation Results Summary .............................................................. 47 Table 4-3. Axial PWSCC at HTS FBM Simulation Results Summary .............................................................. 50 Table 4-4. Axial ODSCC at TSP Location Excluded from GL 95-05 FBM Simulation Results Summary....... 52 Table 4-5. Circumferential ODSCC at Freespan Dings FBM Simulation Results Summary ............................. 54 Table 4-6. Axial ODSCC at Freespan Dings FBM Simulation Results Summary ............................................. 56 Table 4-7. Combination of Probability of Leakage Results ................................................................................ 58 Table A2-1: Watts Bar U2R3 SG Tube Structural and Condition Monitoring Limits ..........64 Table A2-2: Updated NDE Sizing Technique Regression and Standard Error .....65 Table A3-1: Watts Bar U2R3 Tube Plug and Stabilization List for SG-1......66 Table A3-2: Watts Bar U2R3 Tube Plug and Stabilization List for SG-2 ......................................................... 67 Table A3-3: Watts Bar U2R3 Tube Plug and Stabilization List for SG-3 ......................................................... 68 Table A3-4: Watts Bar U2R3 Tube Plug and Stabilization List for SG-4 ......................................................... 72 Table A4-1. Watts Bar U2R3 Circumferential ODSCC at HTS Sizing Summary ............................................ 73 Table A5-1: Watts Bar U2R3 Possible Loose Part Indications (PLPs) .............................................................. 76 Table A6-1: Watts Bar U2R3 Tube Proximity Indications (PRX), All SGs....................................................... 85 SG-CDMP-20-23-NP March 2021 Revision 2 Page 5 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 List of Figures Figure 3-1. Watts Bar Unit 2 VOL Indications Traceable to Pre-Service Inspection ........................................ 16 Figure 3-2. Watts Bar U2R3 AVB Wear Indications Map ................................................................................ 18 Figure 3-3. Watts Bar U2R3 TSP Wear Indications Map .................................................................................. 20 Figure 3-4. Watts Bar U2R3 Circumferential ODSCC at Top of Tubesheet Expansions Tubesheet Map ........ 24 Figure 3-5. Watts Bar SG-1 Hot Leg Channel Head Cladding Indication ......................................................... 32 Figure 3-6. Watts Bar SG-3 Hot Leg TSP (Center) Bobbin Noise Comparison - U2R1 Through U2R3 ......... 34 Figure 3-7. Watts Bar U2R3 +POINT Hot Leg TTS Expansion Transition Noise Distribution, All SGs ........ 35 Figure 4-1. Watts Bar Unit 2 AVB Wear Growth Rate Distributions ............................................................... 38 Figure 4-2. Watts Bar Unit 2 TSP Wear Growth Rate Distributions ................................................................. 39 Figure 4-3. Watts Bar Unit 2 Maximum Depth POD Distribution for Circumferential ODSCC at HTS ......... 43 Figure 4-4. Watts Bar Unit 2 Circumferential ODSCC Undetected Flaw Length Distribution ........................ 43 Figure 4-5. Watts Bar Unit 2 Simulated Circumferential ODSCC PDA Distribution ....................................... 44 Figure 4-6. Watts Bar Unit 2 Circumferential ODSCC Maximum Depth Growth Distribution, 617oF ............ 44 Figure 4-7. Watts Bar Unit 2 Circumferential ODSCC Length Growth Distribution, 617oF ............................ 45 Figure 4-8. Watts Bar Unit 2 Circumferential ODSCC PDA Growth Distribution, , 617oF ............................. 45 Figure 4-9. Watts Bar Unit 2 Maximum Depth POD Distribution for Axial ODSCC at HTS .......................... 48 Figure 4-10. Watts Bar Unit 2 Maximum Depth POD Distribution for Axial PWSCC at HTS ........................ 50 Figure 4-11. Watts Bar Unit 2 POD Distribution for Axial ODSCC at Freespan Dings <5v............................ 56 Figure A5-1. Watts Bar U2R3 Tube Possible Loose Part Indications in All SGs ............................................. 84 Figure A6-1. Watts Bar U2R3 Tube Proximity Indications in All SGs............................................................. 90 List of Attachments - Watts Bar U2R3 As-Implemented SG Inspection Scope .......................................................... 62 - Watts Bar U2R3 SG Tube Structural and Condition Monitoring Limits .................................. 64 - Watts Bar U2R3 Tube Plug and Stabilization Listing ............................................................... 66 - Watts Bar U2R3 Circumferential ODSCC at HTS Sizing Summary ........................................ 73 - Watts Bar U2R3 Possible Loose Part (PLP) Indications........................................................... 76 - Watts Bar U2R3 Tube Proximity Indications ........................................................................... 85 SG-CDMP-20-23-NP March 2021 Revision 2 Page 6 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Executive Summary The Watts Bar U2R3 steam generator (SG) inspection was conducted after cumulative service equivalent to approximately 3.354 effective full power years (EFPY). The Cycle 3 duration was 1.359 EFPY. This was the third in-service inspection (ISI) of the Watts Bar Unit 2 SGs. No SG primary-to-secondary leakage was reported during this operating interval. Watts Bar U2R3 represents the second inspection of the first 60 effective full power months (EFPM) Technical Specification sequential period. Based on the U2R3 SG eddy current and visual inspection data, there were five existing degradation mechanisms in the Watts Bar Unit 2 SGs and four new degradation mechanisms were detected during the U2R3 inspection. The existing degradation mechanisms following Watts Bar U2R3 are:

Volumetric Indications due to Fabrication and Installation (Pre-service)

Mechanical Wear at Anti-Vibration Bars (AVBs)

Mechanical Wear at Tube Support Plates (TSPs)

Circumferential Outer Diameter Stress Corrosion Cracking (ODSCC) at the Hot Leg Tubesheet Expansion Transition Axial ODSCC at the Hot Leg Tube Support Plate Intersections Axial ODSCC at Hot Leg Expansion Transition/Sludge Pile, NEW Mechanism Axial ODSCC at Freespan Dings, NEW Mechanism Circumferential ODSCC at Freespan Dings, NEW Mechanism Axial Primary Water Stress Corrosion Cracking (PWSCC) at Hot Leg Expansion Transition, NEW Mechanism No tubes have exhibited degradation exceeding the tube integrity criteria given in the Degradation Assessment (DA) for the U2R3 outage (Reference 3). No tubes required in situ pressure testing to support the Condition Monitoring (CM) assessment based on the DA and Electric Power Research Institute (EPRI) In Situ Pressure Test Guidelines (Reference 6). Condition monitoring assessment for each existing degradation mechanism was demonstrated to satisfy the steam generator structural and leakage performance criteria at U2R3 for degradation mechanisms not addressed by Nuclear Regulatory Commission (NRC) Generic Letter 95-05 voltage-based repair criteria for axial ODSCC at tube support plate and flow distribution baffle (FDB) locations. Evaluation of degradation addressed by Generic Letter 95-05 are provided separately.

A total of 189 tubes were plugged as a result of the U2R3 SG inspections. Seventy-one (71) of these were stabilized for circumferential degradation prior to plugging. A summary of the number of plugged tubes in the Watts Bar Unit 2 SGs following U2R3 is provided below.

No. No. Total No.

No. Plugged Plugged Plugged SG  % Plugging Tubes Prior to During After U2R3 U2R3 U2R3 1 4,674 25 9 34 0.73%

2 4,674 34 22 56 1.20%

3 4,674 14 122 136 2.91%

4 4,674 21 36 57 1.22%

Total 18,696 94 189 283 1.51%

Revision 1 of this document provides the results of the final Operational Assessment (OA). The final OA has been performed considering the degradation detected and degradation growth rates observed with respect to future inspection plans. The OA concludes that SG structural and leakage integrity will be maintained through to the end of the Cycle 4 operating period for all degradation mechanisms not addressed by the NRC GL 95-05 voltage-based alternate repair criteria for axial ODSCC at TSP and FDB intersections. The SG-CDMP-20-23-NP March 2021 Revision 2 Page 7 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 evaluations for steam line break and conditional probability of burst evaluations for degradation addressed by GL 95-05 are provided separately.

SG-CDMP-20-23-NP March 2021 Revision 2 Page 8 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 1.0 Introduction This Condition Monitoring and Operational Assessment (CMOA) has been developed for the Tennessee Valley Authority (TVA) following the Watts Bar Unit 2 3rd Refueling Outage (U2R3) SG tube in-service inspection and assessment conducted in the fall of 2020. The assessments have been performed to meet the requirements and intent of NEI 97-06 Revision 3 (Reference 2). In preparation for the inspection, and to assure that the inspection adequately supports the CM and final OA evaluations required by NEI 97-06, the licensee documented the inspection scope together with the qualification of the applied nondestructive examination (NDE) techniques (References 3 and 9). This process provides assurance that the NDE techniques are appropriate for detection and measurement and to support development of degradation growth rates, repair criteria, and integrity limits for the degradation mechanisms assessed.

Based on the results obtained from the Watts Bar U2R3 inspections, a CM assessment was performed on a defect-specific basis, by demonstrating compliance with integrity criteria through comparison of reported flaws with calculated structural pressure and leakage integrity limits. The flaw indication sizing by NDE was compared to the defect-specific condition monitoring criteria specified in the DA which are repeated in . All indications detected in this inspection were below the integrity limits, and therefore, met the condition monitoring requirements provided, with the exception of degradation mechanisms addressed by GL 95-05. Refer to Reference 22 and Reference 29 for the results and evaluations performed in accordance with GL 95-05. A final OA has been performed considering the indications detected during U2R3 and degradation-specific growth rates. The OA concludes that steam generator tube structural and leakage integrity will be maintained until the end of the upcoming one cycle inspection interval of 1.38 EFPY.

The industry has developed guidelines for SG assessment and TVA has developed a long-term strategic plan to meet or exceed the industry guidelines. The Watts Bar U2R3 SG inspections have been led by the following industry guidelines and SG integrity programs:

  • 2-SI-68-907 Watts Bar Nuclear Plant Unit 2 Surveillance Instruction for Steam Generator Tubing In-service Inspection and Augmented Inspections (Reference 8)

Revision 1 to this document provides the methods and results of the final OA to demonstrate satisfaction of the SG performance criteria for structural and leakage integrity through to the end of Cycle 4.

This Operational Assessment document was prepared in accordance with the Westinghouse Quality Management System (QMS).

SG-CDMP-20-23-NP March 2021 Revision 2 Page 9 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 2.0 Watts Bar U2R3 Primary Side Inspection Program 2.1 Base Scope Inspection Plan The inspection program, as required by the EPRI Pressurized Water Reactor (PWR) SG Examination Guidelines (Reference 1) and the EPRI SG Integrity Assessment Guidelines (Reference 5), addressed the existing and potential degradation mechanisms for the Watts Bar Unit 2 SGs.

The Watts Bar U2R3 SG inspection plan met or exceeded the requirements of the Reference 1 EPRI Examination Guidelines and was aligned with the Reference 8 TVA Watts Bar SG Surveillance Instructions.

The Watts Bar U2R3 eddy current inspection scope as implemented during the outage is shown in . The defined scope implemented during U2R3 included the following:

  • 100% bobbin inspection of all open tubes in all four SGs full length and tube Rows 1 through 4 to the top support from both the hot leg (HL) and the cold leg (CL) sides.
  • 100% +POINT' probe inspection of tube Rows 1 through 4 from the top support on the HL side to the top support on the CL side.
  • +POINT probe Special Interest inspections of tube locations with non-resolved bobbin and/or Array probe signals.
  • 100% +POINT probe inspection of the hot leg top of tubesheet (TTS) region from HTS+2/-2 inches in all SGs.
  • 50% Combination bobbin and Array probe inspection from C06 to CTS-2 inches in a checkerboard pattern. This inspection included all cold leg peripheral tubes two tubes deep, all tubes not inspected by the U2R3 cold leg combination bobbin and Array probe program and all possible loose part (PLP) indications detected as part of the combination bobbin and Array probe scope in the U2R3 inspections.
  • 100% +POINT or Array probe inspection of all DNTs 2 volts.
  • 100% +POINT or Array probe inspection of all DNGs 5 volts in the HL straight lengths, U-bends and the top TSP on the CL side.
  • Scope expanded to 100% +POINT or Array probe inspection of all DNGs 2 volts in SG-2.
  • Scope expanded to 100% +POINT probe inspection of all DNGs 5 volts in SG-4. DNGs <5 volts were inspected with the 100% full length base bobbin program. Note: The bobbin coil probe is qualified for axial ODSCC at DNGs.
  • 25% +POINT or Array probe inspection of all DNGs 2.
  • Scope expanded to 100% +POINT or Array probe inspection of all DNGs 2 volts in SG-2.
  • Scope expanded to 100% +POINT probe inspection of all DNGs 5 volts in SG-4. DNGs <5 volts were inspected with the 100% full length base bobbin program. Note: The bobbin coil probe is qualified for axial ODSCC at DNGs.
  • 100% +POINT probe inspection of any DNT or DNG signal located within 1.0 inch or less of an MBM.
  • 100% +POINT probe inspection of TSP mix residual signals that could cause a 1.0 Volt bobbin signal to be missed or misread as required by NRC Generic Letter 95-05.

SG-CDMP-20-23-NP March 2021 Revision 2 Page 10 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3

  • +POINT or Array probe inspection of tubes surrounding known locations of foreign objects according to the inspection recommendations provided in Table 9-2 of Reference 3.
  • +POINT or Array probe inspection of all tubes within a two-tube pitch of the region surrounding any foreign object wear or PLP locations.
  • +POINT probe inspection of SG-3 tube Row 47 Column 48 at H01 and all tubes within one tube of this location at the same elevation.
  • +POINT probe inspection of bobbin proximity (PRO or PRX) signals >1.25 volts with corresponding adjacent PRO or PRX signals.
  • 100% visual inspection of all installed tube plugs from the primary side on both the HL and CL side.
  • Visual inspection in all SGs of channel head primary side HL and CL in accordance with Reference 25 inclusive of the entire divider plate to channel head weld and all visible clad surfaces. A follow-up inspection of the channel head clad anomaly in the hot leg of SG-1 was performed to confirm that the Reference 11 assessment remains applicable.

2.2 Inspection Expansion The base inspection program for freespan dings 2 volts detected a circumferential ODSCC indication at a freespan ding in SG-2. The inspection program for freespan dings was increased to 100% of the freespan dings 2 volts in the hot leg, U-bend, and cold leg portions of the tubing in SG-2. In this expansion program an additional indication of circumferential ODSCC and an axial ODSCC indication in freespan dings were detected in SG-2. No additional expansion was required for the detection of the axial flaw since 100% of the dings 2 volts were inspected with the +POINT or array probes.

The 25% base inspection program for freespan dings 5 volts detected axial ODSCC indication at a freespan ding in SG-4. The inspection program for freespan dings was increased to 100% of the freespan dings 5 volts in the hot leg, U-bend, and cold leg portions of the tubing in SG-4. No additional expansion was required for dings <5 volts since the bobbin coil technique is qualified for axial flaw detection in dings <5 volts and a 100% full-length bobbin coil inspection was performed as a planned base program.

Additional localized expansions were performed with the +POINT and Array probes as appropriate for indications of potential loose parts (PLPs) and metallic objects found during post sludge lance tubesheet visual inspection in order to examine the affected or potentially affected tubes.

2.3 Inspection Results 2.3.1 Eddy Current Inspection Results Table 2-1 presents a filtered summary of the tube NDE indication results based on data relevant to evaluating tube integrity. The files listed below the table were generated by the Westinghouse ST MAX' eddy current results data management system and used to create the table.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 Table 2-1. Watts Bar U2R3 SG Eddy Current Inspection - Final Indication Summary Indications Condition SG-1 SG-2 SG-3 SG-4 ADI Absolute Drift Indication 0 0 0 0 BLG Bulge 6 1 1 3 DDI Distorted Dent Indication 2 0 0 1 DDS Distorted Dent Signal 15 9 4 7 DFI Differential Freespan Indication 0 0 0 0 DFS Differential Freespan Signal 67 62 107 79 DNG Ding in the Freespan 1816 2041 833 510 DNT Dent at a Support 19 2 0 6 Distorted Support Indication DSE 1 1 4 2 Excluded from GL 95-05 DSI Distorted Support Indication 200 313 390 325 DSS Distorted Support Signal 12 4 0 2 Distorted Support Indication DSV 0 1 10 1 Greater Than Upper Repair Limit DTI Distorted Tubesheet Indication 0 0 0 0 DTS Distorted Tubesheet Signal 0 3 1 1 GEO Geometry Variation 6 1 1 0 IDC Inside Diameter Chatter 1 3 1 1 MAI Multiple Axial Indications 3 8 82 2 MBM Manufacturing Burnish Mark 39 60 89 103 MCI Multiple Circ Indications 0 0 9 0 MRS Mix Residual Signal1 1 2 1 0 PCT Percent Indication 10 13 52 31 PLP Possible Loose Part 73 18 22 24 PRX Proximity Signal 20 108 12 50 PSP Partial Support Plate Indication 0 0 1 0 PVN Permeability Variation 26 11 23 23 SAI Single Axial Indication 21 49 84 75 SCI Single Circ Indication 6 4 37 18 SPB Support Plate Block Indication 8 0 0 0 TBP To Be Plugged 9 22 122 36 VOL Volumetric Indication 14 2 8 15 WAR Wear from Array 5 5 59 10 Note 1: The MRS signals are generated based on an automated data analysis sort performed separately from the production analysis process. The MRS locations are then loaded into the database manually. The counts of the MRS signals listed are only those which were inspected this outage with enhanced techniques.

SG-1: SG1_ENGINEERING_DATA_11-08-20_0220.XLSX SG-2: SG2_ENGINEERING_DATA_11-08-20_0220.XLSX SG-3: SG3_ENGINEERING_DATA_11-08-20_0220.XLSX SG-4: SG4_ENGINEERING_DATA_11-08-20_0220.XLSX 2.3.2 Degradation Mechanism Summary During U2R3, eight degradation mechanisms were reported, in addition to three categories of axial ODSCC at TSP intersections. Table 2-2 provides a listing of the degradation mechanisms and the number indications reported in each SG.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 Table 2-2. Watts Bar U2R3 Degradation Mechanism Summary Mechanism SG-1 SG-2 SG-3 SG-4 Total AVB Wear 10 13 3 28 54 TSP Wear 0 0 49 3 52 Foreign Object Wear 0 0 0 0 0 Volumetric Indication (PSI) 13 2 7 14 36 Axial ODSCC - TSPs (95-05) 200 313 390 325 1228 Axial ODSCC - TSPs (95-05) >URL 0 1 10 1 12 Axial ODSCC Excluded from 95-05 0 0 3 0 3 Circ ODSCC - HTS 6 1 44 18 69 Axial ODSCC - HTS 0 0 3 1 4 Axial PWSCC - HTS 0 1 0 0 1 Circ ODSCC -- Freespan Ding 0 2 0 0 2 Axial ODSCC - Freespan Ding 0 1 0 1 2 2.4 Tube Plugging and Stabilization A total of 189 tubes were plugged during the Watts Bar U2R3 SG in-service inspection. All tubes with circumferential indications were stabilized through the degraded region prior to tube plugging. Tables A3-1 through A3-4 provides the listing of tubes plugged, stabilizer location and type, and reason for plugging.

Following U2R3 tube plugging, Watts Bar has a total of 283 (1.51%) tubes plugged in all SGs.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 3.0 Condition Monitoring Condition Monitoring is the assessment performed on observed indications of tube degradation to confirm that the SG Integrity Performance Criteria embodied in the CM limits have not been violated. It is essentially a backward-looking evaluation for assessing the condition of the tubes over the prior operating cycle. The CM limits, derived from the structural limits in accordance with the EPRI SG Integrity Assessment Guidelines (Reference 5) and the SG Degradation Specific Management Flaw Handbook (Reference 4), are provided in the outage DA (Reference 3) and provided in Attachment 2 of this document.

Discussion of the indications in relation to the CM requirements is provided in the following subsections.

3.1 Existing Degradation Mechanisms The EPRI PWR SG Examination Guidelines (Reference 1) require that the existing degradation mechanisms identified in the DA be subject to appropriate inspection programs to comply with the plant Technical Specifications. This section addresses the existing SG degradation mechanisms for Watts Bar U2R3 and the indications identified.

3.1.1 Volumetric Indications due to Tube Fabrication and Installation (Pre-Service)

Indications of volumetric tube wall loss (VOLs) were reported during the pre-service inspection (PSI) of the Watts Bar Unit 2 SGs. Table 3-1 provides the flaw character of VOLs detected during PSI or traced to being present at PSI through historical data review. The locations of the VOLs are spatially scattered throughout the tube bundle as shown in Figure 3-1 with no apparent pattern that would indicate a localized cause. It should be noted that VOL indications located on the hot leg, cold leg, and U-bend are shown on the same tubesheet map.

Although most of the VOL indications observed during the PSI were less than 30% through-wall (TW),

several tubes exceeded the 40% TW threshold with the largest indication measuring 57% TW. All tubes with a detected VOL sized at greater than or equal to 38% TW were plugged following the PSI. Based on lead analyst sizing, all the indications are relatively consistent dimensionally with an axial extent of about 0.25 inch and circumferential extent of about 0.5 inch.

All previously identified VOL indications corresponding to this degradation mechanism were detected during the U2R3 inspection with no change in signal character. No additional or new VOL indications were reported this inspection.

These indications are categorized as existing degradation, as discussed in the Reference 3, The indications were created during tube manufacture or installation and therefore do not represent a service induced active degradation mechanism for which an Operational Assessment is required to be performed. However, these indications will be monitored every inspection for changes in signal character which would indicate active in-service degradation is occurring. No active in-service degradation is occurring for this mechanism.

Based on the inspection data and prior condition monitoring results for this mechanism in comparison to the limits identified in Attachment 2, structural integrity requirements have been met at the U2R3 inspection.

The largest VOL indication remaining in service is 32%TW (Table 3-1) and is bound by the 58%TW CM limit for a 0.5 inch flaw, thereby satisfying the structural integrity performance criteria. Regarding volumetric indications, satisfaction of structural integrity implies satisfaction of leakage integrity at accident conditions since steam line break (SLB) accident condition pressure differential is much smaller than 3PNO for pressure-only loading of volumetric flaws. Therefore, CM has been satisfied for degradation associated pre-service volumetric indications at the Watts Bar U2R3 inspection.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 Table 3-1. Watts Bar Unit 2 VOL Indications from Pre-Service Inspection SG Row Col Volts Deg Ind Per Chn Locn Inch1 PType 1 6 74 0.24 134 VOL 30 3 HTS -0.19 ZRSNM 1 3 99 0.15 107 VOL 17 2 C14 0.08 NPUM4 1 10 38 0.21 122 VOL 23 4 C12 -2.5 NPSNM 1 10 55 0.11 101 VOL 11 4 C13 32.84 NPSNM 1 14 18 0.13 84 VOL 14 2 AV1 3.8 ZPUN4 1 14 98 0.16 112 VOL 18 2 C14 1.69 ZPUN4 1 28 83 0.6 96 VOL 46 4 C14 0.49 NPSNM 1 30 73 0.07 46 VOL 5 4 C13 28.64 NPSNM 1 31 80 0.22 95 VOL 24 2 C14 1.84 ZPUN4 1 32 65 0.08 108 VOL 8 4 C01 2.4 NPSNM 1 32 96 0.28 99 VOL 27 3 C14 0.52 ZRSNM 1 34 77 0.08 107 VOL 6 2 C14 1.52 ZPUN4 1 34 87 0.47 102 VOL 41 4 C14 0.2 NPSNM 1 35 48 0.16 58 VOL 18 2 H08 25.26 ZPUN4 1 38 72 0.44 99 VOL 39 2 AV4 29.55 ZPUN4 1 39 72 0.15 91 VOL 17 4 C14 -2.74 NPSNM 1 41 73 0.3 92 VOL 30 4 C14 0.58 NPSNM 2 5 103 0.13 106 VOL 14 4 H01 0.62 NPSNM 2 5 110 1.61 91 SVI 46 P4 H01 0.44 ZRSNM 2 21 16 0.1 74 VOL 11 4 H03 33.19 NPSNM 2 25 28 0.78 11 VOL 48 4 C10 13.37 NPSNM 2 27 31 2.1 13 VOL 57 4 C01 12.32 NPSNM 3 19 37 0.13 206 VOL 14 4 C13 2.74 NPSNM 3 21 41 0.18 80 VOL 20 4 C01 3.88 NPSNM 3 22 43 0.13 82 VOL 15 4 C01 1.46 NPSNM 3 32 46 0.33 110 VOL 32 4 H01 4.89 NPSNM 3 38 42 0.19 118 VOL 21 4 H01 1.75 NPSNM 3 38 42 0.1 95 VOL 11 4 H01 1.12 NPSNM 3 38 58 0.19 51 VOL 21 4 H06 40.09 NPSNM 3 40 42 0.42 95 VOL 38 4 H01 1.97 NPSNM 4 1 87 0.14 68 VOL 21 4 H01 2.96 NPSNM 4 3 106 0.1 240 VOL 10 4 C11 12.01 NPSNM 4 8 84 0.13 240 VOL 20 4 H04 21.84 NPSNM 4 9 44 0.07 69 VOL 10 4 H07 30.94 NPSNM 4 20 46 0.07 57 VOL 10 4 H07 22.43 NPSNM 4 21 31 0.11 257 VOL 18 4 H06 9.99 NPSNM 4 21 31 0.09 258 VOL 14 4 H06 2.03 NPSNM 4 21 31 0.05 0 VOL 7 4 H06 17.06 NPSNM 4 23 77 0.12 101 VOL 13 4 C09 7.31 NPSNM 4 27 46 0.13 42 VOL 20 4 H04 22.89 NPSNM 4 28 95 0.1 71 VOL 16 4 H04 25.6 NPSNM 4 29 100 0.3 55 VOL 30 4 C13 36.1 NPSNM 4 30 14 0.18 230 VOL 20 4 C10 9.02 NPSNM 4 30 35 0.21 46 VOL 23 4 C10 8.8 NPSNM 4 38 84 0.1 44 VOL 15 4 H04 3.39 NPSNM Note: Shaded cells with bold text indicate the tube has been plugged.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 Watts Bar Unit 2 Model D3 Pre-Service Volumetric Indications Tubesheet Map

- Base Tubes

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0 10 20 30 40 so 60 70 80 90 100 uo COLUMN Figure 3-1. Watts Bar Unit 2 VOL Indications Traceable to Pre-Service Inspection 3.1.2 Mechanical Wear at Anti-Vibration Bars Wear at the anti-vibration bars (AVBs) was first detected during the Watts Bar U2R1 SG inspections and is categorized as an existing degradation mechanism. This mechanism occurs due to tube interaction with the AVB support structures in the tube U-bends resulting from flow-induced vibration (FIV) in the upper tube bundle. The mechanical wear process is related to the tightness of the upper bundle assembly as expressed in the distribution of tube to AVB support structure gaps. In general, at plants with similar support structures, AVB wear indications do not represent a challenge to structural or leakage integrity standards between inspections. Indications of AVB wear require plugging should observed indication depths exceed the SG Technical Specification plugging criterion of 40% TW.

Table 3-2 provides a summary of the AVB wear indications reported in each SG during the Watts Bar U2R3 inspection. There were 54 indications in 50 tubes reported. The maximum depth sizes ranged from 7 to 21% TW as measured from the bobbin coil sizing Appendix I Technique 96041.1. Nineteen (19) of these indications were newly reported during U2R3. The table displays the eddy current signal parameters for the U2R3 bobbin inspection and the corresponding depth of each indication. A graphical display of the distribution of the AVB wear indications is provided in Figure 3-2. These results compare favorably to the projected worst-case projected flaw of 30% TW determined in the Operational Assessment performed following the prior inspection (Reference 14). Table 3-3 provides a comparison of AVB wear parameters for U2R1 through U2R3.

The bobbin probe sizing of the largest AVB wear indication observed during U2R3 was measured at 21% TW which occurred in two tubes: SG-1 R36C91 at AV3 and SG-4 in tube R42C36 at AV3. The CM limit for AVB wear degradation is 66% TW for a 0.6 inch length flaw. All AVB wear reported during U2R3 are well below this limit, with the largest depths being 21% TW. Based on the inspection data for this mechanism in comparison to the limits identified in Attachment 2, structural integrity requirements have SG-CDMP-20-23-NP March 2021 Revision 2 Page 16 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 been met at the U2R3 inspection. Therefore, all AVB wear indications satisfied the CM structural integrity performance criterion. No tubes were plugged for this mechanism.

For volumetric wear flaws with pressure-only loading condition, tube burst and ligament tearing (i.e., pop-through) are coincident, therefore, satisfaction of the tube burst criteria at 3PNO also satisfies the AILPC at steam line break differential pressure. Additionally, satisfaction of the structural integrity criterion implies satisfaction of the leakage integrity criterion at accident conditions since steam line break accident condition pressure differential is much smaller than 3PNO for pressure-only loading of volumetric flaws. Therefore, CM has been satisfied for TSP wear degradation at the Watts Bar U2R3 inspection.

Table 3-2. Watts Bar U2R3 AVB Wear Indications Summary SG-1 SG-2 SG-3 SG-4 Limiting/Total No. Indications 10 13 3 28 54

<20% TW 9 13 3 27 52 20-29% TW 1 0 0 1 2 30% TW 0 0 0 0 0 Number of Tubes 10 13 3 24 50 Max % TW 21 18 16 15 21 12.6 Average % TW 13.0 12.8 11.7 12.4 (ave of all SGs)

Number of New Ind. 5 5 2 7 19 Growth/EFPY Maximum 2.94 0.74 -2.21 2.94 2.94 0.15 Average 1.18 -0.64 -2.21 0.32 (ave of all SGs) 95th Percentile N/A1 N/A1 N/A1 2.94 2.94 th Note 1: Insufficient number of data points to calculate a 95 percentile using the Benards approximation method.

Table 3-3. Watts Bar U2R3 AVB Wear Summary U2R3 U2R2 U2R1 No. Indications 54 35 17

<20% TW 52 34 17 20-29% TW 2 1 0 30-39% TW 0 0 0

>=40% TW 0 0 0 No. Tubes 50 16 17 Maximum % TW 21 20 20 Average % TW 12.6 13.0 11.9 Number of New Ind. 19 18 17 Growth/EFPY Max. 2.94 3.98 20.00 Average 0.15 1.78 15.84 th 95 Percentile 2.94 3.98 20.00 SG-CDMP-20-23-NP March 2021 Revision 2 Page 17 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Watts Bar Unit 2 Model D3 AVB Wear Indications Tubesheet Map

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10 20 30 40 50 60 70 80 90 100 COLUMN Figure 3-2. Watts Bar U2R3 AVB Wear Indications Map 3.1.3 Mechanical Wear at Tube Support Plates Wear at TSPs was first detected during the Watts Bar U2R1 SG inspections and is categorized as an existing degradation mechanism. Flow-induced vibration that causes tube support wear is governed primarily by secondary side thermal hydraulic characteristics and the size tolerances of the tube-to-support structure gaps.

This suggests that wear rates are subject to specific conditions and will vary between plants and even between SGs at a specific plant. In general, at plants with similar support structures, TSP wear indications do not represent a challenge to structural or leakage integrity standards between inspections. Indications of TSP wear may require plugging should observed indication depths exceed the SG Technical Specification plugging criterion of 40% TW.

Table 3-4 shows the depth of indications detected during Watts Bar U2R3 with historical results. There were 52 indications in 34 tubes reported during U2R3. This represents an increasing trend of TSP wear as 5 indications were reported at U2R1, 19 at U2R2 and 52 at U2R3. The maximum depths of the flaws reported during U2R3 ranged from 3% TW to 27% TW as measured from the bobbin sizing Appendix I Technique 96042.1. Forty-nine (49) of the 52 indications were in SG-3, 3 were in SG-4 and none in SG-1 and SG-2. Thirty-three (33) of these indications are newly reported during U2R3. The table displays the eddy current signal parameters for the U2R3 bobbin inspection and the corresponding degradation level. A graphical display of the distribution of the TSP wear indications is provided in Figure 3-3. The location and elevation of the TSP wear indications appear to be predominantly aligned with the feedwater nozzle inlet between the C05 and C06 tube supports. These results compare favorably to the projected worst-case projected flaw of 47% TW determined in the Operational Assessment performed following the prior inspection (Reference 14).

The bobbin probe sizing of the largest TSP wear indication observed during U2R3 was measured at 27% TW in SG-3 tube Row 48 Column 65 at C05. The CM limit for TSP wear degradation is 64% TW for of the full 0.75 inch width of the TSP. All TSP wear reported during U2R3 are well below this limit, with the largest depths being 27% TW. Based on the inspection data for this mechanism in comparison to the limits identified in Attachment 2, structural integrity requirements have been met at the U2R3 inspection.

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      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Therefore, all TSP wear indications satisfied the CM structural integrity performance criterion. No tubes were plugged for this mechanism.

Based on the inspection data for this mechanism in comparison to the limits identified in Attachment 2, structural integrity requirements have been met at the U2R3 inspection.

Regarding TSP wear indications, satisfaction of structural integrity implies satisfaction of leakage integrity at accident conditions since steam line break accident condition pressure differential is much smaller than 3PNO for pressure-only loading of volumetric flaws. Therefore, CM has been satisfied for degradation associated with TSP wear indications at the Watts Bar U2R3 inspection.

Table 3-4. Watts Bar U2R3 TSP Wear Indications - All SGs U2R1 U2R2 U2R3 Count SG Row Col Locn Inch1 Ind

%TW %TW %TW 1 3 45 63 C06 -0.24 PCT - - 4 2 3 46 56 C05 -0.26 PCT - 5 5 3 3 46 56 C06 -0.21 PCT - 7 9 4 3 46 57 C06 0 PCT - - 6 5 3 46 58 C06 -0.24 PCT - - 7 6 3 46 59 C05 -0.24 PCT - - 6 7 3 46 60 C06 -0.24 PCT - - 4 8 3 46 61 C05 0 PCT - 12 13 9 3 46 61 C06 -0.03 PCT - - 4 10 3 46 65 C06 -0.21 PCT - - 8 11 3 47 56 C06 -0.21 PCT - 6 8 12 3 47 57 C06 -0.19 PCT - 6 6 13 3 47 58 C05 0.36 PCT - - 3 14 3 47 59 C02 0 PCT - 7 7 15 3 47 59 C05 0.12 PCT - 12 11 16 3 47 59 C06 -0.23 PCT - - 3 17 3 47 60 C03 0.3 PCT - - 4 18 3 47 60 C06 -0.19 PCT 14 21 26 19 3 47 62 C06 -0.21 PCT - - 7 20 3 47 63 C05 0 PCT - - 17 21 3 47 63 C06 -0.19 PCT - - 5 22 3 47 64 C05 -0.02 PCT - - 5 23 3 47 64 C06 0 PCT - 10 10 24 3 47 65 C05 0 PCT - - 9 25 3 48 51 C06 0.44 PCT - - 5 26 3 48 53 C05 -0.26 PCT - - 5 27 3 48 55 C05 -0.09 PCT - - 4 28 3 48 55 C06 -0.2 PCT - - 3 29 3 48 56 C05 0 PCT - - 5 30 3 48 56 C06 0 PCT - - 6 31 3 48 58 C03 0.14 PCT - - 5 32 3 48 58 C05 -0.02 PCT - - 6 33 3 48 60 C05 0.33 PCT - - 7 34 3 48 60 C06 -0.19 PCT 11 21 26 35 3 48 61 C02 0 PCT - 6 10 36 3 48 61 C05 -0.26 PCT - 11 16 37 3 48 61 C06 -0.14 PCT - - 7 SG-CDMP-20-23-NP March 2021 Revision 2 Page 19 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 U2R1 U2R2 U2R3 Count SG Row Col Locn Inch1 Ind

%TW %TW %TW 38 3 48 63 C05 -0.26 PCT - - 4 39 3 48 63 C06 -0.21 PCT - - 4 40 3 48 64 C05 0 PCT - 18 20 41 3 48 64 C06 0 PCT - 9 8 42 3 48 65 C05 -0.02 PCT - 22 27 43 3 48 66 C05 -0.2 PCT - - 3 44 3 48 66 C06 -0.19 PCT 5 16 22 45 3 49 59 C05 -0.23 PCT - - 7 46 3 49 59 C06 -0.14 PCT - - 8 47 3 49 60 C02 0 PCT - - 5 48 3 49 60 C06 -0.24 PCT 10 19 21 49 3 49 61 C06 -0.21 PCT 7 13 16 50 4 48 46 C06 -0.18 PCT - - 8 51 4 48 77 C05 0.15 PCT - - 7 52 4 49 74 C06 0.12 PCT - 5 5 Watts Bar Unit 2 Model 03 TSP Wear Indications Tubesheet Map Base Tubes X SG4 50 ~ - - - ~ - - - ~ - - - ~ - - - ~ - - - ~ - - - ~ - - - ~ - - - - - - - - - - - - - - - - ~

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000000000 000000000 000000000 0 000000000 000000000 0 000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 0 15 0000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 00 0000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 00 00000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000 00000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000 10 00000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000 00000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000 00000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000 rooooooooo 000000000 000000000

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000000000 000000000 000000000 0000 000000000 0000 000000000 0000 0 0 0 10 20 30 40 so 60 70 80 90 100 110 COLUMN Figure 3-3. Watts Bar U2R3 TSP Wear Indications Map 3.1.4 Axial ODSCC at the Tube Support Plates (95-05 Applicable)

Axially oriented ODSCC at tube support plate intersections is a prevalent degradation mechanism in SGs with Alloy 600MA (mill annealed) tubing. Axial ODSCC at the hot leg tube support plates was first detected at Watts Bar Unit 2 with the bobbin probe during the U2R2 inspection. There were eight axial ODSCC indications confirmed with the +POINT probe at hot leg TSPs out of 193 distorted support plate indications reported during Watts Bar U2R2. At the time of U2R2, the NRC Generic Letter 95-05 (Reference 15) alternate repair criteria for axial ODSCC at TSP intersections was not in effect.

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      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 In June of 2019, the NRC approved the application of GL 95-05 for Watts Bar Unit 2 and it was implemented during the U2R3 inspection (Reference 21). The approved request permits degraded tubes with axial ODSCC indications confined to within the thickness of the TSPs with bobbin voltages 1.0 volt to remain in service. Further, the approved criteria permit tubes to remain in service that have indications confined to within the thickness of the tube support plates with bobbin voltages 1.0 volt, but less than or equal to the upper voltage repair limits, if a rotating pancake coil (RPC) or acceptable alternative inspection does not detect degradation. The upper repair limits for TSP and flow distribution baffle (FDB) locations are provided in Table 3-5. Condition monitoring is performed using the methodology described in GL 95-05 (Reference 15) using probabilistic techniques for calculating the accident induced leak rate and conditional probability of tube burst for the distribution of DSI indications reported during the inspection. The acceptance criteria for accident induced leakage is 3 gpm and for the conditional probability of burst is 1x10-2 for the faulted SG.

During U2R3 inspection, a significant increase in distorted support plate indications (DSIs) and DSVs occurred over Cycle 3. A total of 1240 DSIs were reported from all SGs in U2R3. Three DSI/DSVs were located at FDB intersections. The maximum bobbin coil voltage was 9.35 volts. A total of 187 DSIs were in excess of 1.0 volts and of these 112 DSIs were confirmed by the +POINT probe as having axial ODSCC within a TSP intersection.

Reference 22 provides an evaluation of axial ODSCC at support intersection in accordance with GL 95-05.

The calculated accident induced leakage rate in the limiting SG (SG-3) for the as-found DSI distribution is 1.85 gpm, which satisfies the 3 gpm leakage acceptance criteria for the faulted SG. The calculated conditional probability of burst in the limiting SG for the as-found DSI distribution is 3.005 x10-2, which does not satisfy the 1x10-2 acceptance criteria for burst probability for SG-3 per GL 95-05 (Reference 15). Therefore, GL 95-05 criteria for axial ODSCC at TSP and FDB intersections have not been satisfied. This condition has been entered into the plant Corrective Action Program and appropriate regulatory notifications have been made. Reference 22 provides additional details.

Table 3-5. Axial ODSCC at TSP and FDB Summary U2R2 U2R3 EFPY 1.995 3.354 Total Number of DSI's and DSVs 193 1240 SG-1 45 200 SG-2 71 314 SG-3 43 400 SG-4 34 326 Maximum Voltage 2.88 9.35 SG-1 1.46 1.66 SG-2 2.88 3.82 SG-3 2.08 9.35 SG-4 1.34 6.06 GL 95-05 SLB Leak Rate and Conditional Probability of Burst Bounding SLB Leak Rate (gpm) n/a 1.85 Bounding Conditional Burst Probability n/a 3.005x10-2 Upper Voltage Repair Limit at TSPs (volts) n/a 2.85 Upper Voltage Repair Limit at FDBs (volts) n/a 1.82 SLB Leak Rate Limit (gpm) n/a 3.0 Conditional Probability of Burst Limit n/a 1x10-2 SG-CDMP-20-23-NP March 2021 Revision 2 Page 21 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 3.1.S Axial ODSCC at Tube Support Plates (GL 95-05 Not Applicable)

Implementation of GL 95-05 voltage-based alternate repair criteria for axial ODSCC degradation at TSP intersections excludes certain tubes and locations from application of the criteria. Confirmed axial ODSCC indications are required to be evaluated through standard tube integrity methodologies as specified in Reference 5. Excluded tubes and locations are identified in Reference 23.

During U2R3, three indications of axial ODSCC at TSP intersections were confirmed with the +POINT probe within GL 95-05 excluded tubes and locations.

Table 3-6 provides a listing of the flaw dimensions of each observed flaw as measured by the +POINT probe using the ETSS I28431 voltage amplitude sizing technique. Line-by-line depth profiling was performed for each flaw to obtain the structural effective depth (SED) and structural effective length (SEL) sizes using the methods described in Reference 4. Calculations of SED and SEL were performed with the Westinghouse Single Flaw Model (SFM) WeakLink feature (Reference 10). Burst pressure and ligament tearing pressure calculations are also performed using the SFM computer code using the Reference 4 methodologies.

The CM limit for a 0.5 inch axial ODSCC flaw is 65% TW for SED using ETSS I28431. Table 3-6 shows that the largest flaw parameters measured were 0.39 inch for total length and 58.2% TW for maximum depth in different tubes. The ligament tearing pressure for a flaw at the CM limit flaw dimensions is 3389 psi, thus satisfying the minimum pressure requirement for leakage integrity (2560 psi). Therefore, all tubes satisfied the CM size criteria for structural and leakage integrity. The limiting flaw for burst and ligament tearing pressure is Tube R47C87 in SG-3. This tube contains an axial flaw with a maximum depth of 51.7% TW with a total length of 0.39 inch. The associated SED and SEL parameters for this flaw are 46.9%TW and 0.32 inch axial length. Using the principles of SED and SEL, the burst and ligament tearing pressures for this flaw is 5787 psi and 6087 psi, respectively, with ETSS I28431 maximum depth and total length measurement uncertainties applied at 95/50. This satisfies the 3840 psi minimum burst pressure requirement associated with 3PNOP and the minimum SLB pressure requirement of 2560 psi for leakage integrity.

A conservative alternate approached was applied that used the largest maximum depth and the largest total length dimensions from Table 3-6 describe a bounding flaw. This assumed flaw would have a maximum depth of 58.2% TW and a total length of 0.39 inch. A flaw of this character has a burst pressure of 4455 psi and a ligament tearing pressure of 4303 psi, with NDE measurement uncertainties applied at 95/50. These results satisfy the minimum burst and leakage pressure requirements for CM (3840 psi for burst and 2560 psi for ligament tearing).

Table 3-6. Watts Bar U2R3 Axial ODSCC at TSP Locations Excluded from GL 95-05 Max. Total SEL, Voltage SED, SG Row Col Deg Ind(1) Locn Inch1 Depth(1) Length,(1) inch (Vpp)(1) %TW

% TW inch 3 21 37 0.32 80 SAI H01 0.13 58.2 0.26 46.9 0.2 3 27 47 0.21 103 MAI H01 0.11 48.6 0.24 42.5 0.17 3 47 87 0.21 95 SAI H04 -0.01 51.7 0.39 46.9 0.32 (1) Sizing from Depth Profiling using ETSS I28431.

3.1.6 Circumferential ODSCC at the Hot Leg Top of Tubesheet The experience with outside diameter stress corrosion cracking (ODSCC) of Alloy 600MA tubing at the tubesheet expansion is extensive. This degradation mechanism was first detected at Watts Bar Unit 2 during the U2R2 hot leg top of tubesheet inspections. During U2R2, five tubes with circumferential ODSCC indications were reported at the top of the tubesheet hot leg expansion transition reported by the +POINT probe. Four of the five indications were single circumferential indications (SCI) and one of the indications is a multiple circumferential indication (MCI).

SG-CDMP-20-23-NP March 2021 Revision 2 Page 22 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 A large increase in the number of circumferential indications at the top of the tubesheet expansion transition was observed during the U2R3 inspection. A total of 69 tubes in all SGs contained circumferential ODSCC at the expansion transition. The largest number of tubes affected were found in SG-3, where 44 tubes were reported with circumferential indications.

Table A4-1 in Attachment A provides a listing of the all indications reported with their associated depths and extents. PDA values were initially determined for all circumferential indications using the quick screening methodology described in Reference 19. The quick screening method provides a tool that permits a PDA assessment of all circumferential ODSCC without time consuming profile evaluations. The quick screen methodology [

]a.c.e. Using the quick screen PDA results, and other flaw size parameters, such as voltage, depth, and length, flaws were selected for more detailed line-by-line depth profiling. A total of 18 tubes containing circumferential degradation were depth profiled. The tubes profiled are listed in Table A4-1.

The flaw sizing parameters listed in Table A4-1 were obtained through data analysis resolution process and line-by-line depth profiling using the technique described in the circumferential cracking segment sizing method (Reference 18). Table 3-7 provides the tube identification for flaws with the largest specific flaw size parameter. [

]a.c.e.

The largest 300 kHz +POINT probe peak-to-peak voltage (Vpp) was 0.62 Vpp as measured through resolution analyst sizing and was located in tube SG-3 R22C66. This was the only flaw that exceeded the Reference 6 initial in situ pressure testing screening value (0.5 Vpp) for proof testing. This flaw was depth profiled and resulted in a PDA of 26.6, which is well below the CM limit of 48.8. Therefore, per Reference 6, no in situ proof testing was required for this tube. The 0.62 Vpp flaw indication was less than the Reference 6 voltage screening criteria for leak testing (1.0 Vpp) and no in situ leak testing is required for this tube per Reference 6. This tube satisfied condition monitoring for structural (burst) and leakage integrity per Reference 6. All other circumferential flaws were less than 0.5 Vpp criterion for proof testing and are inherently less than the 1.0 Vpp criterion for leak test; demonstrating through the Reference 6 criteria that all tubes satisfy structural and leakage integrity for condition monitoring.

Condition monitoring is also demonstrated through flaw sizing. The largest PDA observed during U2R3 for circumferential ODSCC at expansion transitions was 35.4 PDA located in tube SG-1 R30C77 as measured through line-by-line depth profiling. This flaw is less than the CM limit of 48.8 PDA (Attachment 2) and therefore satisfies the structural integrity performance criterion. A flaw of this size results in a burst pressure of 5688 psi, with NDE measurement uncertainties applied at 95/50; which is well above the minimum burst pressure requirement of 3840 psi associated with 3PNOP. Monte Carlo calculations of the burst pressure was performed with the Westinghouse Single Flaw Model software (Reference 10) using the methodologies described in Reference 4.

Based on the pulled tube and in situ pressure test data provided in Reference 6, a lower bound threshold for expected leakage at steam line break (SLB) conditions for circumferential ODSCC in hardroll expansions is approximately 1.99 volts. This data served as the basis for the conservative 1.0 volt in situ pressure test screening criteria for leak testing at SLB conditions. The largest voltage observed during U2R3 was 0.62 volt and was well below the voltage thresholds where leakage has been observed, thereby demonstrating satisfaction of the accident induced leakage performance criterion (AILPC) for condition monitoring.

The largest circumferential flaw observed at the expansion transition region was measured at 35.4 PDA.

This is bounded by the prior OA projection where a 50.2 PDA flaw was predicted, thereby confirming a conservative OA method was used.

SG-CDMP-20-23-NP March 2021 Revision 2 Page 23 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Condition Monitoring requirements have been satisfied at the U2R3 inspection for degradation associated with circumferential ODSCC at the hot leg tubesheet expansion transitions. All the tubes with indications of circumferential ODSCC were stabilized through the region of the flaw and plugged.

Table 3-7. Watts Bar U2R3 Circumferential ODSCC at HTS Bounding Size Parameters

+POINT Maximum Arc 300kHz Depth, Length, Bounding SG Row Col Ind Locn Vpp %TW Deg. PDA Parameter 3 22 66 SCI HTS 0.62 52 212 26.61 Voltage 1 44 30 SCI HTS 0.19 96 81 19.91 Depth 3 23 56 MCI HTS 0.27 75 319 28.29 Arc Length 1 30 77 SCI HTS 0.27 86 172 35.42 PDA Note: Sizing parameters derived from line-by-line depth profiling.

Watts Bar U2R3 Circumferential ODSCC at HTS Tubesheet Map I Base Tubes

  • SG-1 A SG-2 SG-3
  • SG-4I so 000000000 oc,ooooocio 000000000 o oo o oooei , 000,-.
  • .:.ooc..oo ao h 101l O U ClOOOO 000000000 OOOOOOOCIO-* ooooooovo C,0 0 000,000 OOOOvC*

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o'llr, oooo 000000000 000000000 0000000001 OOOOOOCIOO 000000000 OOOCIOOOOO 00~

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  • 000000000 000000000 000000000 10(100 000000000 0000000 0 000000000 000000000~ C*OOOOOOOO ooooooc,o 000000000 1 00000 40 00 oooooei o o 0000 00000 oooc,00000, 0000000('10 000000 000 000000000 000,:,oc,ooo 0¢00000 000 000000 0 00 ,000000000 0 00000000 00000000
  • ocooooooo 000000000 0000000001 00000000 DOQO OQODOOOOO 000000000 OQQDOOOOO OOOOOQOOO 000000000 OOOOOQQOO ,000000000 00QOD0000 00,:,00 0000000 00 0000 00000 000000000* 000000000 000000000 0000¢0000 oc-0000000 000000000, 35 - -- - - - -

0000000 000000000 000000000 000000000 000000000~ 000000000 *:000000000 000000000, 000000000 00 00000,:,00 000000000 0000 00000 OOOC*OOOOO* 00000,00,:.,0 C.,00000000 0000¢000:.,0 000000000 000000000, ~00

,nonoooo1 aoouooooo 0 0000000 00¢000000 oooooo cio 00000 000 OOQOOOQOO 00 000000 000000000 000 1 000000000 000000000 000000000 oooocoooo 000000000 000000000 000000000 000000000* OOOOC*OOOO oooc 30

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  • 001,)00000 000000000 000000000 000000000 000000000 00()000000 000000000 000000000 00000 0 000000000
  • 000000000 000000000 OOOQQOOOO 000000000~ 000000000 000000000 000000000 OQOOOOOOO OOOC-00 00 QOCIOOOO-:,(l OOOOOOOtJO OQOOtJOOOO OOQ000000 OtJOCIOOOClQ 00000000tl CIOOOOQQOCI 000000000 ,000000000 0000000

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00 ,000000,,00 000000000 000000000 0000 ~ 000 oooooooc.,oi 000000000 00000000 000000000 000000000* *¢00000 25 000 000000000 COOOQOOOO 0000,.::,00 000000000 000000000~ 000000000 000000000 00 000001 ooooc,ooo~t ~ooooooo CIC o,:,ao -000000000 000D0000D 0 0000000 ooooaoooa OOOCI0 :000, 000000000 ooooaoooa ooao oooo 000000000 OOOOOOOOCI QOOO 000000000 000000000 000000000 oooc:,00000 oooooo ft('i o o * ::iooo* ~oo 000000000 000 00000 0~000000~; ~00000000 00000 000000000 000000000 000000000 000000000 0000 0 -.:i o~ 000000 _, 0 ooo eo oooo 0000 0 00001 000000000 000000000 ,

20 00000 000000,:ioo 0000000 00 000000000 -000000000 OOOOOO IIO O 0000000. , 00000 ~ 0 0000 0 0000 ooooooooo l oooooooo,o )

~06000 000000000 000000000 oaooooaoo aoooaoooo 000000000 , 00000~ 00 000000000 ,:i.oaaooooo 1000000000 OOOOOOOOCI 0 0000-00 000000000 000000000 000000000 000 00000 000000000 oeooooeo o 000000000 000000000, 000000000 *0000,00000 0 000000 000000000 000000000 000000000 -:,00,:.,00000 0000~ 0(10 C.,00000 0 0 oooooo e,,ei 000000000 0¢0000000, *000000000 0 15 --

0000000 000000000 cooooooo0 ,000000000 000000000 000-:1 0 00~ 000000000 000000000 000000000, oooc,oo.:i

  • oc,000000 00 0000000 00000000(:l 000000000 oaooooaoo aoooaoooa oooaooooo , oaoooaooo aoooaoooa 0000000 0 000000000 ,000000000 00 0001)0000 000000000 OC)0000000 000000000 000000000 000000000 000000 00 000000000 000000000 ,000000000 0000 0000 1 000

,00000000 000000-:ioo 000000000 *OQOOOOOOO 000000000 oooooeooo~ 000000000 000000000 000000000 OOOOC:-0000 00000000,0 000 10 00000000 000000,:,00 0000000 00 000000000 oooi:,00000 0000000¢0 00000000 0 t .-.;,00000000 000000000 000000" 0 ,,0000000,:i oi:,o OQOOOOOO 000000000 000000000 OCI0000000 000000000 1 0000000'00 0000000001 000000000 000000000 OQOOQQOOO ?00000000 OC*O Q0000000 000000000 0000000QO 000000000 000000000 OOOQOOLJOO 000000000 OOOIJ00000 *OOOOQOOOO 0(10000000

  • OOOOOOOIJO QOU OOt.'000000 000000?00 00000000 000000000 ?00000000* 0000000~0 OOOOOQOOO 00000000,Q oeoeooooo 000000000 000000000 *¢0:,0Q 5

00000000"' 000000000 OOOOOllOC.O ,oooovoooo 000000000 000000 ~ 0 i.1000 000 OOOOOOOG>O 0000000,;:,o 000000000 cooocoooc OC)tt,;)

000000000 000000000 OIJIOOOOOOO 0000000-0C* C/00000000 000000000 000000000 )00000000 000000000 00000000: l :000000000 C,t,0*.)

000000000 000000,:,00 OOOOOf)OOO OOC'IOOOOOl'"J OOOOOC-000 00000/'"JOOOi OOt.'000000 C'IOOOOOOOO 000000000 OOOOOOt.'00, *OOOOOOOOC/ l'.'l('(F) 000000000 OOOOOQOOO OOOQQOOOO 000000000 OOOOQOOOO 000000000 ~00000000 000000000 OOQOOOOOO OOOOOQOOO '000000000 <.J OO*)

0 0 0 10 20 30 40 so 60 70 80 90 100 110 COLUMN Figure 3-4. Watts Bar U2R3 Circumferential ODSCC at Top of Tubesheet Expansions Tubesheet Map SG-CDMP-20-23-NP March 2021 Revision 2 Page 24 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 3.1.7 Axial ODSCC at Expansion Transition and Sludge Pile During the U2R3 SG inspection, three indications of axial ODSCC at expansions transitions and one indication within the sludge pile were reported. This is the first occurrence of this degradation mechanism at Watts Bar Unit 2. Axial ODSCC at expansion transition and sludge pile region has been re-categorized as an existing degradation mechanism.

Tube R23C56 in SG-3 contained an axial ODSCC indication 0.5 inch above the hot leg tubesheet within the sludge pile region. This tube also contained a circumferential ODSCC indication at the bottom of the hot leg roll transition. Per Reference 6, flaws separated by [ ]a.c.e are not interacting and can be treated separately for tube integrity evaluations. The axial separation distance of the lower edge of the axial crack to the upper edge of the circumferential crack was measured to be [ ]a.c.e by the Ghent probe, which is considered to provide the most accurate measurement technique since it is a transmit-receive probe that minimizes the effects of the hardroll geometry. The +POINT probe and the pancake coil (as referenced by Reference 6) both measured a separation distance of [ ]a.c.e. All three separation distances satisfy the criterion for the axial and circumferential flaws to be evaluated separately for tube integrity assessments.

Furthermore, the axial flaw is located entirely above the tubesheet in the unexpanded freespan portion of the tube, while the circumferential flaw is located inside the tubesheet at the bottom edge of the hardroll.

Table 3-8 provides a listing of the flaw dimensions of each observed flaw as measured by the +POINT probe using the ETSS I28431 voltage amplitude sizing technique. Line-by-line depth profiling was performed for each flaw to obtain the structural effective depth (SED) and structural effective length (SEL) sizes using the methods described in Reference 4. Calculations of SED and SEL were performed with the Westinghouse Single Flaw Model (SFM) WeakLink feature (Reference 10). Burst pressure and ligament tearing pressure calculations are also performed using the SFM computer code using the Reference 4 methodologies.

The CM limit for a 0.5 inch axial ODSCC flaw is 65% TW. Table 3-8 shows that the largest flaw was measured at a total length of 0.45 inch and a maximum depth 60% TW in different tubes. The ligament tearing pressure for a flaw at the CM limit flaw dimensions is 3389 psi, thus satisfying the minimum pressure requirement for leakage integrity (2560 psi). Therefore, all tubes satisfied the CM size criteria for structural and leakage integrity. The limiting flaw for burst and ligament tearing pressure is Tube R23C56 in SG-3.

This tube contains an axial flaw with a maximum depth of 47.6% TW with a total length of 0.45 inch. The associated SED and SEL parameters for this flaw are 43.3%TW and 0.30 inch axial length. Using the principles of SED and SEL, the burst and ligament tearing pressures for this flaw is 6131 psi and 6474 psi, respectively, with NDE measurement uncertainties applied at 95/50. This satisfies the 3840 psi minimum burst pressure requirement associated with 3PNOP and the minimum SLB pressure requirement of 2560 psi for leakage integrity.

As a defense in-depth assessment, the largest maximum depth and the largest total length dimensions from Table 3-8 are assumed to be combined to describe a bounding flaw. This assumed flaw would have a maximum depth of 60% TW and a total length of 0.45 inch. A flaw of this character has a burst pressure of 4158 psi and a ligament tearing pressure of 3814 psi, with ETSS I28431 maximum depth and total length uncertainties applied at 95/50. These results satisfy the minimum burst and leakage pressure requirements for CM (3840 psi for burst and 2560 psi for ligament tearing).

Condition Monitoring requirements have been satisfied at the U2R3 inspection for degradation associated with axial ODSCC at the hot leg tubesheet expansion transitions and sludge pile. All the tubes with indications of axial ODSCC were plugged.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 Table 3-8. Watts Bar U2R3 Axial ODSCC at Expansion Transition/Sludge Pile Max. Total SEL, Voltage SED, SG Row Col Deg Ind Locn Inch1 Depth(1) Length,(1) inch (Vpp) %TW

% TW inch 3 23 56 0.19 95 SAI HTS 0.5 47.6 0.45 43.3 0.30 3 23 66 0.23 83 SAI HTS 0.2 52.8 0.23 45.7 0.18 3 24 65 0.17 78 SAI HTS 0.6 48.1 0.20 39.9 0.17 4 22 69 0.38 41 SAI HTS -0.11 60.0 0.10 46.7 0.09 (1) Sizing from Depth Profiling using ETSS I28431.

3.1.8 Axial PWSCC at Expansion Transition During the U2R3 SG inspection, a single indication of axial PWSCC at the hot leg tubesheet expansion transition was reported. This is the first occurrence of this degradation mechanism at Watts bar Unit 2.

Axial PWSCC at expansion transitions has been re-categorized as an existing degradation mechanism.

Tube R17C100 in SG-2 contained an axial PWSCC indication at the hot leg tubesheet expansion transition.

The flaw was measured with +POINT probe sizing technique ETSS 20511.1 phase-based sizing technique.

Line-by-line depth profiling was performed for each flaw to obtain the SED and SEL sizes using the methods described in Reference 4. Calculations of SED and SEL were performed with the Westinghouse SFM WeakLink feature (Reference 10). Table 3-9 provides the measured flaw size and the SED/SEL dimensions from depth profiling. The maximum depth of the flaw was 68% TW. Burst pressure and ligament tearing pressure calculations are also performed using the SFM computer code using the Reference 4 methodologies.

The flaw was measured at a maximum depth of 68% TW with a total length of 0.11 inch. The burst and ligament tearing pressures for this flaw is 5661 psi and 7072 psi, respectively, with NDE measurement uncertainties applied at 95/50. This satisfies the 3840 psi minimum burst pressure requirement associated with 3PNOP and the minimum SLB pressure requirement of 2560 psi for leakage integrity.

Condition Monitoring requirements have been satisfied at the U2R3 inspection for degradation associated with axial PWSCC at the hot leg tubesheet expansion transitions. All the tubes with indications of axial PWSCC were and plugged.

Table 3-9. Watts Bar U2R3 Axial PWSCC at Expansion Transition Max. Total SEL, Voltage SED, SG Row Col Deg Ind Locn Inch1 Depth(1) Length,(1) inch (Vpp) %TW

% TW inch 2 17 100 0.43 23 SAI HTS 0.04 68 0.11 54.73 0.082 (1) Sizing from Depth Profiling using ETSS 20511.1.

3.1.9 Circumferential ODSCC at Freespan Dings During the U2R3 SG inspection, two indications of circumferential ODSCC at freespan ding locations were reported. This is the first occurrence of this degradation mechanism at Watts Bar Unit 2. Circumferential ODSCC at freespan ding locations has been re-categorized as an existing degradation mechanism.

The larger of the two circumferential flaws was contained in SG-2 Tube R17C109 at C14-2.02 inches and was coincident with a 26 volt ding as measured from the bobbin coil. The flaw was confirmed by a magnetically biased Ghent probe. The ding was measured with a circumferential extent of 168 degrees. The flaw was measured at 0.55 Vpp and a circumferential extent of 57 degrees (Table 3-10). [

]a.c.e SG-CDMP-20-23-NP March 2021 Revision 2 Page 26 of 90

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WESTINGHOUSE NON-PROPRIETARY CLASS 3

[

]a.c.e, which translates to a depth of 66% TW from the probe calibration curve. This correlates well with the voltage-based depth sizing of ETSS I28432 used for axial flaws, which yields a 66.5% TW depth for a 0.55-volt flaw. The PDA of this flaw conservatively applied the maximum depth over the full extent of the flaw length (10.5 PDA). A flaw with a depth of 66% TW with a circumferential extent of 57 degrees has a burst pressure of 7239 psi and a ligament tearing pressure of 4035, with NDE measurement uncertainties applied at 95/50. This satisfies the 3840 psi minimum burst pressure requirement associated with 3PNOP and the minimum SLB pressure requirement of 2560 psi for leakage integrity. Additionally, the flaw size of 10.5 PDA is below the CM limit of 48.8 PDA (Attachment 2).

An additional assessment was applied to the circumferential ODSCC flaw at Tube R17C109 in SG-2, that assumed the flaw length extends to the constraints of the 168 degree ding circumferential extent. Applying the uniform 66% TW depth over the full 163 degree circumferential ding extent results in a simple PDA of 30.8 PDA. A flaw of this character has a burst pressure of 5982 psi and a ligament tearing pressure of 3179, with NDE measurement uncertainties applied at 95/50. This satisfies the 3840 psi minimum burst pressure requirement associated with 3PNOP and the minimum SLB pressure requirement of 2560 psi for leakage integrity. Additionally, the critical crack length for which a 100% TW flaw satisfies structural integrity is 175 degrees (Attachment 2), which bounds the size of this ding.

Since the 0.55 volt flaw voltage in Tube R17C109 in SG-2 exceeded the initial in situ pressure test screening value of 0.5 volt for proof testing, additional screening was required based on flaw sizes following the guidance of Reference 6. The flaw size of 10.5 PDA and length of 57 degrees length were well below the 48.8 PDA and 175 degree length screening criteria for proof testing. The 0.55 volt flaw is also less than the 1.0 volt threshold for leak testing. Therefore, structural and leakage CM requirements had been satisfied per Reference 6 with no in situ pressure testing being required.

The second circumferential ODSCC indication observed during U2R3 was in SG-2 Tube R7C58 at H02-1.95 inches and was coincident with a 27 volt ding. The ding was measured at a circumferential extent of 101 degrees. The flaw was not confirmed with a magnetically biased Ghent probe; indicating that a flaw is not present. The Ghent probe is a transmit-receive probe that reduces the effects of geometric anomalies, such as dings, more so than the motorized rotating pancake coil (MRPC) surface riding probes. However, the +POINT probe showed changes in signal character over time when compared to the pre-service inspection results. Therefore, a flaw is assumed based on the +POINT probe. The flaw was measured at 0.06 volt with a circumferential extent of 25 degrees. It is evident that the small extent of the flaw is influenced by the near horizontal ding signal. Therefore, the flaw extent is assumed traverse the full extent of the ding, 101 degrees. [

]a.c.e, the phase-based flaw depth was determined to be 67% TW. Assuming a uniform flaw depth of 67% TW over the full 101 degrees of the ding circumferential extent produces a PDA of 18.8. This is significantly less than the CM PDA limit of 48.8 PDA. Therefore, the structural integrity for CM has been satisfied. The associated burst and ligament tearing pressures of this flaw are 6866 psi and 3145 psi, respectively, with NDE measurement uncertainties applied at 95/50. This satisfies the 3840 psi minimum burst pressure requirement associated with 3PNOP and the minimum SLB pressure requirement of 2560 psi for leakage integrity. Additionally, the critical crack length for which a 100% TW flaw satisfies structural integrity is 175 degrees (Attachment 2), which bounds the size of this ding.

Condition Monitoring requirements have been satisfied at the U2R3 inspection for degradation associated with circumferential ODSCC at freespan dings. All the tubes with indications of circumferential ODSCC were and stabilized through the region of the flaw and plugged.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 Table 3-10. Watts Bar U2R3 Circumferential ODSCC at Freespan Dings Flaw Ding Bobbin Flaw Max.

Circ Circ Ding SG Row Col Voltage Ind Locn Inch1 Depth(1)

Extent, Extent, Vpp (Vpp)  % TW Deg Deg 2 17 109 0.55 SCI C14 -2.02 66(1) 57 168 26 2 7 58 0.06 SCI H02 -1.95 67(1) 25 101 27 Note 1: Flaw depth obtained from vector subtraction 3.1.10 Axial ODSCC at Freespan Dings During the U2R3 SG inspection, two indications of axial ODSCC at freespan ding locations were reported.

This is the first occurrence of this degradation mechanism at Watts Bar Unit 2. Axial ODSCC at freespan ding locations has been re-categorized as an existing degradation mechanism.

Tube R9C86 in SG-2 contained an axial ODSCC indication coincident with a freespan ding at H02+1.27 inch. The ding was measured at 13 volts by the bobbin probe and the full length of the ding was 0.96 inch. The flaw was measured with +POINT sizing technique ETSS I28432. Table 3-11 provides the NDE sizing characteristics for this flaw. The flaw was measured at maximum depth 65% TW with an axial total length of 0.29 inch. A flaw of this character has a burst pressure of 4143 psi and a ligament tearing pressure of 3800 psi, with ETSS maximum depth and total length uncertainties applied at 95/50. These results are conservative as the concept of structural equivalent depth and length were not applied.

Satisfaction of the minimum burst and leakage pressure requirements for CM (3840 psi for burst and 2560 psi for ligament tearing) was demonstrated.

Tube R49C84 in SG-4 contained an axial ODSCC indication coincident with a freespan ding at AV2+1.32 inch. The ding was measured at 16 volts by the bobbin probe and the full length of the ding was 0.79 inch. The flaw was measured with +POINT sizing technique ETSS I28432. Table 3-11 provides the NDE sizing characteristics for this flaw. The flaw was measured at maximum depth 70% TW with an axial total length of 0.19 inch. A flaw of this character has a burst pressure of 4354 psi and a ligament tearing pressure of 3957 psi, with NDE measurement uncertainties applied at 95/50. These results are conservative as the concept of structural equivalent depth and length were not applied. Satisfaction of the minimum burst and leakage pressure requirements for CM (3840 psi for burst and 2560 psi for ligament tearing) was demonstrated.

The CM limit for a 0.5 inch axial length flaw is 61% TW for structural equivalent depth or [ ]a.c.e TW a.c.e for maximum depth using the recommended factor of [ ] to convert SED to maximum depth per Reference 5. Both flaws listed in Table 3-11 were bounded by the CM limit depth and length requirements.

Therefore, condition monitoring for structural integrity is satisfied. The ligament tearing pressure for a 0.5 inch axial length flaw at the CM limit is 3358 psi, thereby satisfying the minimum pressure for leakage integrity, 2560 psi.

Both axial freespan ding ODSCC flaws identified in Table 3-11 exceeded the Reference 6 initial in situ pressure test screening criteria of 0.5 volts, thereby requiring additional screening based on flaw dimensions.

The next sequential screening criteria is comparison of the measured flaw lengths to the critical crack length as defined by the axial length where a 100% TW flaw satisfies the minimum burst pressure requirement associated with 3PNOP. The critical crack length is 0.45 inch. Both flaws listed in Table 3-11 are less than the critical crack length and in situ pressure testing to demonstrate structural integrity is not required. The voltages of both flaws are less than the 1.0 volt threshold for leak testing, thereby satisfying leakage integrity requirements without in situ pressure testing.

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      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Condition Monitoring requirements have been satisfied at the U2R3 inspection for degradation associated with axial ODSCC at freespan dings. All the tubes with indications of axial ODSCC were plugged.

Table 3-11. Watts Bar U2R3 Axial ODSCC at Freespan Dings Total Ding Bobbin Max.

Voltage Length, (1)

Axial Ding SG Row Col Ind Locn Inch1 Depth(1)

(Vpp) inch Extent, Vpp

% TW inch 2 9 86 0.50 SAI H02 1.27 65 0.29 0.96 13 4 49 84 0.64 SAI AV2 1.32 70 0.19 0.79 16 (1) Sizing from Depth Profiling using ETSS I28432 3.2 Potential Degradation Mechanisms The EPRI Pressurized Water Reactor (PWR) SG Examination Guidelines (Reference 1) require that the potential degradation mechanisms identified in the DA be subject to appropriate inspection programs to comply with the plant Technical Specifications. This section addresses the potential degradation mechanisms listed in the Reference 3 degradation assessment for Watts Bar U2R3.

3.2.1 Mechanical Wear Due to Foreign Objects Given both the recent and historical industry operating experiences, Watts Bar site-specific observations as well as regulatory attention given to foreign objects, this degradation mechanism is classified as potential for the Watts Bar U2R3 inspection. The top of tubesheet secondary side FOSAR performed along with a 100%

bobbin full length, 100% +POINT probe hot leg tubesheet and 50% X-PROBE' cold leg checkerboard pattern inspection was used to address the potential nature of this degradation mechanism. The tube locations surrounding known loose parts and foreign objects remaining in the secondary side of the SGs were also inspected during Watts Bar U2R3 in accordance with Reference 3. Although a significant number of foreign objects have been observed in the Watts Bar Unit 2 SGs during the pre-service, no tube degradation associated with the presence of these objects has been identified during the U2R3 inspections. Since plant start-up, very few metallic objects have been identified within the secondary side of the SGs. All but two have been removed from the SGs. None of the objects found have resulted in wear to the tubes.

During the Watts Bar U2R3 eddy current inspections, a total of 137 PLP indications were reported over the four SGs from all eddy current probe types. These indications and associated eddy current parameters are listed and mapped in Attachment 5 (Table A5-1 and Figure A5-1). It is notable that this PLP indication count is artificially inflated due to a number of indications called by the bobbin and Array probe being resolved as NDF based on follow-up examination with the +POINT probe. There was no tube wall degradation detected by eddy current testing coincident with any of the PLP indications during Watts Bar U2R3. Visual inspections were performed from the SG secondary side, where practicable, and identified a variety of metallic foreign objects, sludge and scale at the top of the tubesheet. Foreign object retrievals were performed on all metallic foreign objects detected at the top of the tubesheet and all metallic foreign objects were removed from all four SGs. During the entirety of the FOSAR inspections, there were no visible signs that any of the objects had caused actual tube wear due to interaction with adjacent tubes. The tube wear potential of the objects and material known to remain resident on the SG secondary side is evaluated as part of the OA.

3.2.2 Outer Diameter Pitting of the Tube Material Pitting is a corrosion-induced degradation mechanism that is heavily influenced by the secondary side chemistry conditions. In the absence of copper materials in the heat exchangers of the secondary systems and assuming adequate dissolved oxygen control, there is little likelihood that pitting will be observed.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 However, recent industry operating experience at one domestic site has caused pitting degradation to come under consideration for plants with Alloy 690TT (thermally treated) tubing which is considered to have greatly improved corrosion resistance to Alloy 600MA. This, in combination with the uncertainty surrounding the extended pre-service layup conditions of the Watts Bar Unit 2 SGs, leads to the consideration of pitting as a potential mechanism for U2R3. There were no indications of outside diameter (OD) pitting of the tube material during the Watts Bar U2R3 inspection.

3.2.3 Tube-to-Tube Contact Wear Tube-to-tube wear can occur due to the interaction that occurs when two or more tubes come in contact with each other. This form of tube degradation would occur in the tube bundle straight sections generally near the mid-span between two subsequent tube support structures. However, it can also occur in the U-bend region where unanticipated secondary side fluid flow characteristics create the conditions that would lead to tube reciprocating motions and interaction.

Low level indications of tube proximity (PRX) were detected during the U2R3 inspections. The listing and a mapping of these indications is shown in Attachment 6 (Table A6-1 and Figure A6-1). As tube-to-tube proximity alone is not a degradation mechanism, it is a condition which could potentially lead to tube interaction with one another. As such, each PRX indication was reviewed through the eddy current data analysis process for an associated volumetric wear indication. Further, +POINT probe testing of any proximity indication was performed where the amplitude was 1.25 volts or greater in accordance with Reference 3. The eddy current results database was also reviewed for adjacent signals which may be indicative of tube-to-tube wear such that they are flagged for further diagnostic testing. No indications of tube-to-tube contact wear were detected through eddy current data analysis or review of the results database during the Watts Bar U2R3 inspections.

3.2.4 Axial and Circumferential PWSCC in the U-bends Recirculating SGs with Alloy 600MA tubes have experienced SCC in the U-bend regions as discussed in NRC Information Notice 97-26 (Reference 16). The bend region is characterized as a location of high residual stresses because of tube deformation from the bending process. In the Watts Bar Unit 2 SGs, the Row 1 and 2 U-bends received a supplemental thermal treatment after the SGs had already been installed.

This supplemental thermal treatment reduces the residual stresses due to forming of the bend. PWSCC related to residual stresses as found after bending Alloy 600MA tubes, though historically limited to Rows 1 and 2, has been observed beyond Row 10 as far as Row 13 in the Comanche Peak Unit 1, Diablo Canyon Unit 2, and Beaver Valley Unit 2 Alloy 600MA tubes. However, no indications of SCC in the U-bend freespan region not associated with a ding location were detected during the Watts Bar U2R3 inspection.

3.2.5 PWSCC at Tube Dents and Dings Freespan localized tube geometric disturbances known as dings have occurred as a result of contact during SG manufacture and tube assembly processes, such as tube insertion through the TSPs and AVB installation.

Dents, however, occur at tube supports and have historically been associated with corrosion of carbon steel TSPs with drilled TSP holes such that inward deformation of the tube occurs. The Watts Bar Unit 2 Model D3 SGs have drilled hole carbon steel TSPs and are, therefore, susceptible to corrosion-induced denting in service. SCC of Alloy 600 tubing has been related to distribution of residual stresses associated with tube deformation and both dent and ding-related SCC has been observed in Alloy 600MA and even more recently in Alloy 600TT tubing. Therefore, axial PWSCC and ODSCC at tube dents and dings were designated as potential degradation mechanisms for Watts Bar U2R3. No indications of PWSCC were detected at dents and dings during the U2R3 inspections.

An Examination Technique Specification sheet (ETSS) technique extension was initially performed during Watts Bar U2R1 in order to support detection of axial and circumferential ODSCC and PWSCC at tube dents and dings with the Array probe for that inspection. Prior to U2R2, the technique extension was revised with SG-CDMP-20-23-NP March 2021 Revision 2 Page 30 of 90

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 additional data that supported justification for U2R2 and subsequent inspections. This extension was performed using the Westinghouse Data Union Software (DUS) and was necessary in order to fully support use of the Array probe for inspection of dents and dings during the base scope inspection. The technique extension process and results has been documented in Reference 13. The conclusions were that both axial and circumferential ODSCC and PWSCC is detectable in dents and dings [ ]a.c.e which supported the inspection scope for dents and dings applied during Watts Bar U2R3.

3.2.6 SCC at Tube Bulges and Overexpansions Tubesheet profilometry was initially performed at Watts Bar Unit 2 in 1986 to identify tube expansion abnormalities. What was primarily identified were portions of the tube that remained unexpanded within the tubesheet often called skip rolls. Also, some tube overexpansions were identified in the profile data as OXPs which was defined as the tubesheet expansion transition being located greater than 0.236 inch above the tubesheet. This is a different definition than used for the more recent model SGs with hydraulic expansions where OXP is used to describe an overexpansion within the tubesheet. Similar differences are present in the use of the term BLG in reference to the Watts Bar Unit 2 SGs. During the Watts Bar Unit 2 pre-service inspection (PSI) performed in 2010, the OXP and BLG codes were used to report a condition above the top of the tubesheet. No SCC was detected at tube bulges and overexpansions during the Watts Bar U2R3 inspections.

3.2.7 Axial ODSCC in the Tube Freespan Cracking of the tube freespan is a degradation mechanism which has susceptibility to occur in SGs with Alloy 600MA. The Watts Bar Unit 1 original SGs first experienced freespan SCC after five cycles of operation. No indications of axial ODSCC in the freespan without a corresponding stress riser (i.e., ding) were detected during Watts Bar U2R3. Refer to Section 3.1.9 for a discussion of axial ODSCC at freespan ding locations.

3.2.8 SCC at Dents and Dings Coincident with a Manufacturing Burnish Mark Cracking coincident with the combination of a dent or ding and a manufacturing burnish mark was identified as a potential degradation mechanism for the Watts Bar Unit 1 original SGs. However, such an indication was never actually detected in the Unit 1 SGs. A 100% sample of locations with both an MBM and a DNT or DNG signal within one inch of each other were inspected with the +POINT probe regardless of the voltage amplitude. No indications of SCC at dents and dings coincident with an MBM were detected during Watts Bar U2R3.

3.3 Resolution for Classification of Indications Indications reported with flaw-like characteristics in the Watts Bar Unit 2 SGs may include those initially reported as distortions of preexisting signals or I-codes. The character of I-code signals is further evaluated by data history review, lead analyst review, or by follow-up examination with alternate nondestructive examination (NDE) techniques. Those indications with a three-letter code ending with an I are compared to historical data and a corresponding S code is created if they have not changed within normal technique variations or to an indication of degradation if they confirm as such. The majority of distorted freespan, tube support and tubesheet bobbin signals from the U2R3 inspection have been cleared by either review of the corresponding +POINT and Array probe data or by data history review. Those indications that were confirmed as degradation with follow up NDE testing were categorized with an analyst for the specific degradation mechanism.

An additional area of consideration relative to the Watts Bar U2R3 inspection was indications of material permeability variations (PVN). PVN indications are not flaw signals or indications of degradation, but rather noise interferences that could compromise detection of flaw signals if present. Inspections with magnetically biased +POINT probe and Ghent coils have typically been used to disposition PVN indications.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 3.4 SG Channel Head Primary Side Bowl and Tube Plug Visual Inspections Visual inspections have been performed of the SG channel head bowl in all SGs during Watts Bar U2R1 through U2R3 outages. These inspections are performed based on industry operating experience and guideline requirements discussed in the Reference 3 Degradation Assessment. Visual inspections of the SG hot leg and cold leg divider plate, inclusive of the entire divider plate-to-channel head weld and all visible clad surfaces, were performed in accordance with Westinghouse Nuclear Safety Advisory Letter (NSAL)

NSAL-12-1 (Reference 12). The inspections were performed using the SG manway channel head bowl cameras. During the U2R1 inspections, a visually apparent indication of missing clad and exposed base metal was noted during inspection of the hot leg side of SG-1. This location was re-inspected during U2R2 and U2R3 to evaluate if continued degradation is occurring. Figure 3-5 shows comparative images of the location from the U2R1, U2R2, and U2R3 inspections.

Figure 3-5. Watts Bar SG-1 Hot Leg Channel Head Cladding Indication The indication in the SG-1 hot leg is located near the manway entry point into the channel head. A collection of information and a detailed assessment of the condition were performed by TVA during U2R1. The as-found condition was evaluated using a combination of high-resolution cameras, dimensional measurements and manual evaluation of the fixity of the clad material. The SG hot leg channel head indication was determined to be acceptable for continued operation following U2R1 as documented in Reference 11. This assessment was determined to remain applicable based on the follow-up visual inspections performed during Watts Bar U2R3. Satisfactory inspection results were observed in all remaining SG channel heads with no further indications of cladding surface degradation.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 All previously installed tube plugs were also inspected from the primary side in all four of the Watts Bar Unit 2 SGs. The inspection results were satisfactory and showed no indication of tube plug leakage or failure. Inspection of the channel head bowl cladding and all installed tube plugs is planned to be performed again during future outages.

3.5 Noise Monitoring Summary Noise measurements were collected throughout the Watts Bar U2R3 bobbin coil and +POINT probe inspections of all four SGs. The automated eddy current data analysis software Real Time Automated Analysis (RTAA') was used to perform bobbin coil noise measurements as recommended in Appendix N of Reference 1 and manual tubesheet noise measurements were recorded for 50 selected tubes per SG. The noise measurements were collected within the regions of interest (ROI) where existing and potential degradation could occur as defined in Reference 3 for the Watts Bar Unit 2 SGs. There are two primary purposes for which the noise was monitored.

The first purpose of noise monitoring is the implementation of exceedance thresholds, which were defined in Reference 3, upon which further evaluation or inspection with alternate probes was performed when necessary. Locations where the noise measurements exceeded the amplitude thresholds set forth in Reference 3 were reviewed by the eddy current data analysis team for the need to perform further analysis or NDE testing. It was determined by the analysis team that none of the identified noise exceedance locations were areas that would potentially mask significant degradation and no further testing was required.

The second purpose of noise monitoring is to support the development of site-specific probability of detection (POD) relations for use in the Operational Assessment. Noise measurements for each ROI were plotted using cumulative distribution function (CDF) on voltage and are to be included in the field service report. The summarized 95th percentile noise levels for each ROI are shown Table 3-12. An example comparison of the noise progression from U2R1 through U2R3 at TSP intersections in SG-3 is provided in Figure 3-6. The noise distributions at this region of interest (ROI) are nearly identical for U2R3 and U2R2, thus indicating no substantial noise progression and therefore no impact on developed noise-based POD curves.

Additional measurements were taken of the +POINT probe noise occurring at the top of the hot leg tubesheet. The measurements were taken from the +POINT 300 kHz frequency in the same 50 tube locations as done in U2R3 in each SG for a total of 200 measurements. Figure 3-7 indicates an increase in the U2R3 noise distribution for the 360 degree noise window as compared to U2R2. Therefore, it is recommended to develop noise-based POD distributions using the most recent noise distributions from U2R3 for the final OA evaluations. While there is an increase in the noise distribution in U2R3, the level of noise is still low as compared to other similar units.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 Table 3-12. Watts Bar U2R3 SG 95th Percentile Bobbin Noise Measurements 95th Percentile Vvm Noise ROI SG-1 SG-2 SG-3 SG-4 FCL - Freespan Cold Leg 0.08 0.09 0.07 0.07 FHL - Freespan Hot Leg 0.08 0.09 0.07 0.07 FUB - Freespan U-Bend 0.08 0.09 0.06 0.07 FWB - Full Support or Baffle 1.07 1.14 1.27 1.38 SCC - Support Center Cold 0.24 0.28 0.29 0.31 SCH - Support Center Hot 0.72 0.73 0.79 0.78 SEC - Support Edge Cold 0.40 0.42 0.37 0.46 SEH - Support Edge Hot 0.67 0.69 0.74 0.82 TCC - Tubesheet Crevice Cold 1.28 1.16 1.38 1.85 TCH - Tubesheet Crevice Hot 1.40 1.13 1.40 1.93 TTC - Top of Tubesheet Cold 2.33 3.29 2.01 1.72 TTH - Top of Tubesheet Hot 2.04 1.89 2.35 1.81 VSC - AVB Center 0.27 0.23 0.21 0.19 VSE - AVB Edge 0.20 0.17 0.13 0.13 Watts Bar Unit 2 Bobbin Coil Noise Trending SG-3 Hot Leg TSP Center Noise Monitoring

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Figure 3-6. Watts Bar SG-3 Hot Leg TSP (Center) Bobbin Noise Comparison - U2R1 Through U2R3 SG-CDMP-20-23-NP March 2021 Revision 2 Page 34 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 All SGs TTS Bottom of Expansion

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0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20 0.22 0.24 0.26 0.28 0.30 Vvm Figure 3-7. Watts Bar U2R3 +POINT Hot Leg TTS Expansion Transition Noise Distribution, All SGs 3.6 Secondary Side Activities 3.6.1 Top of Tubesheet Cleaning A top of tubesheet deposit cleaning process was performed in all four SGs during Watts Bar U2R3. There are two main purposes of the cleaning process. The first is to remove hardened deposits that preferentially form at the top of the tubesheet and the second is remove and filter out any loose parts or foreign objects that have migrated to the SG secondary side during operation. The mass of deposit material and debris removed by the top of tubesheet cleaning process is summarized in Table 3-13. There were no issues or interferences from internal SG components incurred during installation of the SG sludge lance tooling.

Table 3-13. Watts Bar U2R3 SG Tubesheet Deposit Removal U2R1 U2R2 U2R3 SG ID (lbs) (lbs) (lbs)

SG-1 24.5 16.5 lbs 13.0 SG-2 22.5 14.5 lbs 10.0 SG-3 27.5 19.0 lbs 10.2 SG-4 35.0 26.5 lbs 22.0 All SGs 109.5 76.5 lbs 55.2 The contents of the sludge lance system in-line grit tank screen were inspected following completion of cleaning of each SG. These confirmed that the process was successful at removing foreign objects and material from the SG secondary side in addition to the hardened sludge deposits. Other contents included a small number of machine curls, small wires, a small spherical bead, and a rectangular metal strip measuring about 1 inch in length. The foreign object evaluations performed prior to service (Reference 17) addressed objects of this nature and size being located at the top of the tubesheet with the conclusion that they would not cause wear in excess of the tube plugging limit over the course of one operating cycle.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 3.6.2 Top of Tubesheet FOSAR A secondary side tubesheet FOSAR has been performed in all four SGs during Watts Bar U2R3 following the top of tubesheet cleaning. The FOSAR inspections included visual examination of tube bundle periphery tubes from both the annulus and tubelane on both the hot and cold legs and through the no tube lane inclusive of the blowdown pipe connections with the tubesheet. A limited top of tubesheet in-bundle visual inspection was also performed for the purpose of assessing the level of hardened deposit buildup in the kidney region.

Table 3-14 summarizes the results from the FOSAR inspections.

Table 3-14. Watts Bar U2R3 SG FOSAR Summary SG Identified Retrieved Remaining 1 6 0 6 2 3 2 1 3 2 2 0 4 8 2 6 All SGs 19 6 13 During Watts Bar U2R3, a total of 6 foreign objects were removed from the top of the tubesheet. The foreign objects retrieved consist of wire bristles, sludge rocks, and hardened scale. Of the 13 objects remaining in the SG secondary side, only 2 of them are believed to be metallic. All objects were assessed and were found not to have a detrimental impact on tube integrity over the next projected cycle. There were no indications of significant ongoing breakdown of existing foreign material exclusion processes at Watts Bar Unit 2. There also was no visible degradation of the SG feedwater blowdown pipe connections in all SGs observed during the FOSAR.

3.6.3 Upper Steam Drum Inspections Visual inspections of the steam drum upper internal components were not performed during U2R3.

A SG steam drum upper internals inspection was performed during Watts Bar U2R2 in SG-2 and SG-3.

Steam drum upper internal inspections were performed for SG-1 and SG-2 during U2R1. The scope of the inspection was focused on evaluating the condition of the modifications made prior to initial operation. The components visually inspected and photographed included the primary moisture separators, secondary moisture separators, drains, gutters, steam vents, piping, deck plate skirts and ladders. These components were inspected for structural integrity, degradation, excessive deposits, flow-assisted corrosion, blockage and overall sound condition. There were no structurally significant anomalies observed during inspection of the upper internals and, therefore, no potential effects on SG tube integrity. It was noted that, in general, a relatively even coat of surface magnetite was identifiable throughout the inspections indicating there are no signs of ongoing material erosion.

3.7 Condition Monitoring Conclusions Based on the Watts Bar U2R3 SG inspection data, all tubes with observed degradation mechanisms satisfied the condition monitoring criteria for structural and leakage integrity, with the exception of degradation evaluated under the purview of NRC GL 95-05 voltage-based alternate repair criteria for axial ODSCC at TSP intersection. This mechanism is evaluated separately and addressed under Reference 22. In situ pressure testing was not required to demonstrate structural and leakage integrity. There was no reported primary-to-secondary leakage prior to the end of the Watts Bar Unit 2 SG inspection interval. No indications of degradation addressed by this report were found to be in excess of the CM limits. The SG performance criteria for operating leakage and structural integrity were satisfied for the preceding Watts Bar Unit 2 SG inspection interval.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 4.0 Operational Assessment Reference 5 requires an Operational Assessment for the next inspection interval to be completed within 90 days from plant restart (Mode 4) when all degradation mechanisms found during the current inspection pass condition monitoring performance criteria. All degradation mechanisms not addressed by GL 95-05 satisfied CM as provided in Section 3. Refer to Reference 22 and Reference 29 for evaluation of degradation addressed by GL 95-05. The OA is a forward-looking evaluation that determines the projected tube integrity performance criteria for the period of SG operation until the next inspection. An operational assessment will be performed to provide justification that the SG structural and leakage integrity is maintained until the end of Cycle 4 operations. The Cycle 4 operating duration is estimated to be 503.9 EFPD (1.38 EFPY), which includes plant coast down.

NOTE: This OA performs an evaluation for degradation mechanisms not covered under the NRC GL 95-05 voltage-based alternate repair criteria for axial ODSCC at TSP intersection. The GL 95-05 evaluation is documented in Reference 22 and Reference 29.

Watts Bar Unit 2 is planning to implement a 1.4% Measurement Uncertainty Recapture (MUR) power uprate for Cycle 4 following U2R3 (Reference 27). Operation at uprated power condition can affect flaw growth rates for tube wear at support structures, such wear at AVB and TSP supports. The SG thermal-hydraulic and tube vibration at the uprated power conditions were evaluated in Reference 28. Reference 28 concluded that the relative stability ratio (RSR) in the U-bend region at the 1.4% uprated conditions is [

]a.c.e. The RSR value is proportional to the dynamic pressure which is the product of the fluid density and the square of fluid velocity (V2). For tube wear mechanisms the amount of tube wear is [ ]a.c.e. A wear growth correction factor is determined [

]a.c.e. Therefore, a conservative correction factor of [ ]a.c.e will be applied to the growth rates obtained prior to the MUR uprating for the Cycle 4 OA. A specific evaluation was not performed for support wear locations within the straight leg portion of the tubing. Westinghouse experience with power uprate evaluations at other plants [

]a.c.e. Therefore, the same [ ]a.c.e correction factor will be applied to TSP wear growth for the Cycle 4 OA.

To mitigate the growth and initiation of axial ODSCC at TSP intersections evaluated through the requirements of GL 95-05, TVA plant management implemented a reactor coolant system hot leg temperature (Thot) reduction program for operations from plant start-up to the mid-cycle outage planned to begin on 09/15/2021. The method of Thot reduction is accomplished through plant operations at 90% reactor power. The reduction in temperature also reduces the growth and initiation of SCC mechanisms evaluated through conventional OA methods (i.e., SCC at tubesheet expansion transitions, ding locations, etc.). Further discussions on the temperature reductions are discussed in Section 4.3.

4.1 Mechanical Wear at AVBs An Operational Assessment was performed for the AVB wear mechanism based on indications left in service and flaw growth rate. This OA used the simplified worst-case degraded tube method described in Reference 5. The worst-case beginning-of-cycle (BOC) flaw size was determined, and a conservative growth rate was applied to project the end-of-cycle (EOC) condition. The EOC flaw size is compared to the AVB wear CM limit identified in Attachment 2 (66%TW) for compliance to the structural and leakage integrity requirements. Use of the CM limit for OA evaluation allows the BOC flaw depths to be in terms of the NDE detected flaw size since the CM limit includes measurement uncertainty at 95/50.

The largest AVB wear indication observed during U2R3 was 21% TW as measured by the Appendix I bobbin sizing technique ETSS 96041.1. Table 3-3 and Figure 4-1 shows that the 95th percentile flaw growth SG-CDMP-20-23-NP March 2021 Revision 2 Page 37 of 90

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 rate over Cycle 2 (3.98 %TW/EFPY) bounds the growth over Cycle 3 (2.94%TW/EFPY). Operating experience has shown that the growth rate significantly reduces following the first cycle of SG operation.

Therefore, the Cycle 1 AVB wear growth was not used. While the actual plant experience provides a 95th percentile growth of 3.98%TW/EFPY. Applying the [ ]a.c.e MUR growth rate factor to this growth rate, a.c.e the growth rate is expected to be [ ] in Cycle 4. A conservative growth rate of 5.0%

TW/EFPY was used. The Cycle 4 duration was conservatively assumed to be 1.5 EFPY. Therefore, the largest AVB wear flaw is projected to be 29% TW (21% TW + 1.5 EFPY5.0 %TW/EFPY). This flaw is significantly bounded by the 66% TW CM limit, thus satisfying the structural integrity performance criterion.

For volumetric wear flaws with pressure-only loading condition, tube burst and ligament tearing (i.e., pop-through) are coincident, therefore, satisfaction of the tube burst criteria at 3PNO also satisfies the AILPC at steam line break differential pressure. Additionally, satisfaction of structural integrity criterion implies satisfaction of leakage integrity criterion at accident conditions since steam line break accident condition pressure differential is much smaller than 3PNO for pressure-only loading of volumetric flaws. Therefore, OA has been satisfied for AVB wear degradation through to the end of Cycle 4.

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%TW Growth/EFPY Figure 4-1. Watts Bar Unit 2 AVB Wear Growth Rate Distributions 4.2 Mechanical Wear at Tube Support Plates An Operational Assessment was performed for the TSP wear mechanism based on indications left in service and a conservative flaw growth rate. This OA used the simplified worst-case degraded tube method described in Reference 5. The worst-case BOC flaw size was determined, and a conservative growth rate was applied to project the EOC condition. The EOC flaw size is compared to the TSP wear CM limit identified in Attachment 2 (64% TW) for compliance to the structural and leakage integrity requirements.

Use of the CM limit for OA evaluation allows the BOC flaw depths to be in terms of the NDE detected flaw size since the CM limit includes measurement uncertainty at 95/50.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 The largest TSP wear indication observed during U2R3 was 27% TW as measured by the Appendix I bobbin sizing technique ETSS 96042.1. Figure 4-2 shows that the 95th percentile flaw growth rate over Cycle 2 (9.0 %TW/EFPY) bounds the growth over Cycle 3 (4.5%TW/EFPY). The growth rate distribution was augmented with results of reanalysis of historical data and conservatively assumed growth from zero when flaws were not detected in the prior inspection. Operating experience has shown that the growth rate typically reduces following the first cycle of SG operation; for Watts Bar Unit 2, the reduction occurred following the second cycle. Therefore, the 9.0% TW/EFPY Cycle 2 TSP wear growth rate was used for plant conditions prior to the MUR uprate. Applying the [ ]a.c.e MUR growth rate factor to this growth rate, the a.c.e growth rate is expected to be [ ] in Cycle 4 following MUR uprate. A growth rate of 10%TW/EFPY will conservatively be used in this assessment. The Cycle 4 duration was conservatively assumed to be 1.5 EFPY. Therefore, the largest TSP wear flaw is projected to be 42% TW (27% TW + 1.5 EFPY10 %TW/EFPY). This flaw is significantly bounded by the 64% TW CM limit, thus satisfying the structural integrity performance criterion.

For volumetric wear flaws with pressure-only loading condition, tube burst and ligament tearing (i.e., pop-through) are coincident, therefore, satisfaction of the tube burst criteria at 3PNO also satisfies the AILPC at steam line break differential pressure. Additionally, satisfaction of structural integrity criterion implies satisfaction of leakage integrity criterion at accident conditions since steam line break accident condition pressure differential is much smaller than 3PNO for pressure-only loading of volumetric flaws. Therefore, OA has been satisfied for TSP wear degradation through to the end of Cycle 4.

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%TW Growth/EFPY Figure 4-2. Watts Bar Unit 2 TSP Wear Growth Rate Distributions 4.3 Stress Corrosion Cracking Watts Bar Unit 2 has identified six stress corrosion cracking (SCC) degradation mechanisms during SG inspections through U2R3. These include axial and circumferential ODSCC at the hot leg tubesheet expansion transition region, axial PWSCC at the hot leg tubesheet expansion transitions, axial ODSCC at TSP intersections, and axial and circumferential ODSCC at freespan dings. These degradation mechanisms SG-CDMP-20-23-NP March 2021 Revision 2 Page 39 of 90

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 require OA to be evaluated for the SG structural and leakage performance criteria over the next inspection interval. The OA for axial ODSCC at TSP intersections is addressed in Reference 29, except for specific TSP intersections excluded from the application of GL 95-05. Three axial ODSCC indications were identified at excluded TSP intersections and therefore require OA through conventional methods described in Reference 5.

Operational assessment of SCC degradation mechanisms will be performed using fully probabilistic methods through application of the Westinghouse Full Bundle Model (FBM) software package (Reference 25). The basic methodology for the fully probabilistic analysis is the same for each degradation mechanism, however, the specific inputs for each mechanism may be different. The basic fully probabilistic analysis method includes:

Determination of the beginning-of-cycle flaw size distribution for undetected flaws. This is typically performed with probability of detection distributions, simulations, and assumptions to develop the postulated flaw size distributions for maximum flaw depth, length and percent degraded area (PDA). The BOC PDA distribution is applicable to circumferential degradation.

Determination of the number of undetected flaws at the BOC. This is determined through trending of flaw initiation and projection or by conservative assumption.

Flaw growth rate distributions for maximum depth, length, and PDA (for circumferential degradation). Flaw growth rate distributions are determined by site-specific analysis of flaws experienced or by using the default growth rate distributions provided in Reference 5.

Determination of the maximum depth-to-structural equivalent depth (SED) correlation. This parameter is applicable to axial flaws and is used to convert a flaw maximum depth to SED as the burst equations of Reference 4 use SED as calculational input. [

]a.c.e.

Total length-to-structural equivalent length (SEL) correlation. This parameter is applicable to axial flaws and is used to convert a flaw total length to SEL as the burst equations of Reference 4 use SEL as a calculational input. [

]a.c.e.

An inspection interval of 1.38 EFPY was applied for evaluations covering full-cycle operation to U2R4. An inspection interval of 0.83 EFPY was applied to evaluations covering operation to the planned mid-cycle outage beginning 09/15/2021.

The remainder of critical inputs to the fully probabilistic model, including tube geometry, material properties, normal operating, accident pressures, and leakage limits are taken from the Reference 3 Degradation Assessment.

The fully probabilistic model combines the BOC flaw sized distributions with the growth distributions to determine the probability of burst (POB), probability of accident induced leakage (POL), burst pressure and accident leak rate at the end of the inspection interval. The results are compared to the following SG performance criteria:

POB, 5%

POL, 5%

Burst Pressure, 3840 psi. This is associated with 3PNOP as specified in Reference 3.

Accident Induced Leak Rate, 1.0 gpm (Reference 3)

To mitigate the growth and initiation of axial ODSCC at TSP intersections evaluated through the requirements of GL 95-05, TVA plant management implemented a reactor coolant system hot leg temperature (Thot) reduction program for operations from plant start-up to the mid-cycle outage planned to begin on 09/15/2021. The method of Thot reduction is accomplished through plant operations at 90% reactor power. Plant operating parameters trending showed that the average Thot in the hottest loop (Loop 4) during Cycle 3 was 617o F. Trending of Cycle 4 data to-date shows the same limiting loop average Thot to be 612oF.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 The SCC cracking mechanisms observed during U2R3 initiated and propagated at 617oF Thot operating conditions. Therefore, SCC growth rate adjustments can be applied using the Arrhenius temperature correction factor (Reference 5) to the operating period of reduced temperature operations from the start of Cycle 4 through to the mid-cycle outage. The associated operating duration is 303 calendar days (0.83 years).

It is assumed that the plant will return to full power operations from the mid-cycle outage to the end of Cycle 4 which is estimated to be 0.55 EFPY. For full operating cycle OA intervals, the SCC growth rates

[

]a.c.e.

4.3.1 Circumferential ODSCC at Tubesheet Expansion Transitions A fully probabilistic full bundle analysis was performed using the Westinghouse Full Bundle Model (FBM) software package (Reference 25). The analysis assessed the SG performance criteria for probability of burst (POB), probability of leakage (POL), burst pressure and accident induced leakage performance criteria for circumferential ODSCC flaws over one full cycle of operation with a duration of 1.38 EFPY and for operation through to the planned mid-cycle outage beginning 09/15/2021.

The fully probabilistic analysis begins with development of flaw detection POD distributions and distributions of undetected flaws. For circumferential ODSCC at the hot leg top of tubesheet, the +POINT probe detection and sizing technique applied during inspections was ETSS 21410.1. A site-specific POD function for maximum flaw depth was developed using the EPRI Model Assisted POD (MAPOD) code (Reference 24). The MAPOD model [

]a.c.e noise window was used in this assessment. The [ ]a.c.e Ahat function from the ETSS 21410.1 data set was also used in this assessment. Figure 4-3 provides the Watts Bar Unit 2 specific log-logistic POD curve for circumferential ODSCC at tubesheet expansion transitions for maximum depth.

The log-logistic POD function produces a 95th percentile maximum depth 95th percentile value of

[ ]a.c.e and [ ]a.c.e at the 50th percentile.

The fully probabilistic analysis uses flaw size distributions for assumed flaws that may not have been detected during the U2R3 inspection. The flaw size parameters for the undetected flaw population include maximum depth, length, and PDA. The undetected flaw distributions describe the BOC flaw sizes to which the flaw growth is applied. The undetected flaw size distributions for each parameter were derived by the following methods:

The undetected maximum depth distribution was developed from the site-specific POD distribution (described above) [ ]a.c.e.

The undetected flaw total length distribution was derived from re-analysis of the U2R2 inspection results for the tubes with circumferential ODSCC flaws observed during U2R3. The resultant length distribution is the N-1 distribution and is taken as the undetected flaw length distribution described with a 95th percentile value of [ ]a.c.e and a 50th percentile value of

[ ]a.c.e of circumferential extent. Figure 4-4 provides the assumed undetected flaw length distribution.

The undetected flaw PDA distribution was derived through [

]a.c.e. The undetected flaw PDA distribution is described th with a 95 percentile of [ ] a.c.e and a 50th percentile of [ ]a.c.e. Figure 4-5 provides the simulation results for the assumed undetected flaw PDA distribution.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 Flaw growth rate distributions for each flaw size parameter, maximum depth, length and PDA, are applied to the BOC flaw distributions. Historical data re-analysis of all circumferential flaws reported during Watts Bar U2R3 was performed to obtain site-specific growth rate distributions for maximum depth, length, and PDA.

There are 53 growth data points from this re-analysis. Analysis of the historical Watts Bar Unit 2 eddy current data was performed to develop site-specific growth rates for circumferential ODSCC at tubesheet expansion transitions. It is noted that a small but conservative adjustment was made to the PDA growth rate distribution as a result of benchmarking the model to the U2R3 inspection results. Figures 4-6, 4-7, and 4-8 show the site-specific growth rates for maximum depth, circumferential length, and PDA, respectively. A prorated growth rate based on [

]a.c.e is used for full-cycle OA durations. The OA for the duration to the mid-cycle outage will conservatively assume full power and temperature conditions.

The number of undetected flaws assumed in the assessment was derived from Weibull failure analysis using the number of circumferential ODSCC expansion transition flaws observed during inspections and from historical data review of U2R3 flaws to U2R2. During U2R3, a total of 69 tubes contained circumferential indications from all SGs with 44 indications in SG-3. Therefore, SG-3 is the most limiting SG for flaw initiation and is used for a Weibull failure projection. Historical eddy current data review performed on the flaws observed in the current U2R3 inspection [

]a.c.e. The Weibull analysis projection using these parameters resulted in 57 incremental tubes at the end of Cycle 4 (U2R4) assuming a full operating cycle length of 1.38 EFPY. Alternate flaw projection methods that were performed using log-logistic and log-normal projections each projected 46 incremental tubes in SG-3 at the end of Cycle 4. Full power and temperature conditions were assumed throughout Cycle 4 for flaw initiation projections.

Therefore, 60 tubes were assumed for the number of flaws to evaluate in the OA. Sensitivity simulations were performed for 70 flaws.

The inputs and assumptions to the fully probabilistic model were benchmarked to the Watts Bar U2R3 results for SG-3. The model conservatively bounded the burst pressure of the most limiting circumferential flaw at U2R3 in SG-3 where 69 flawed tubes were reported in all SGs.

The POB and POL results for the 60 and 70 undetected flaw assumption are provided in Table 4-1. Six cases were evaluated for varying assumptions as provided in the table, including assumptions for cycle duration, temperature and number of undetected flaws. All results were within the 5% performance criteria for burst and accident induced leakage probabilities. Additionally, the accident induced leakage satisfies the accident induced leakage limit of 1.0 gpm for both cases. The lower 5th percentile burst pressure also satisfies the minimum burst pressure requirement of 3840 psi for all cases. Therefore, circumferential ODSCC at the hot leg expansion transition meets the OA performance criteria for structural and leakage integrity for one full cycle of operation.

Table 4-1. Circumferential ODSCC at HTS FBM Simulation Results Summary Prob. of Prob. of Burst Leak Rate Number of Cycle Burst Leakage Pressure at at Lower Undetected Temperature Duration (POB) (POL) Lower 5% 5%

Flaws Assumption (EFPY) (%) (%) (psi) (gpm) 60 Prorated 1.38 0.052 3.876 5785 0.776 o

60 617 F 0.83 0.003 0.364 5945 0 60 617o F 1.38 0.068 4.038 5751 0.800 70 Prorated 1.38 0.067 4.519 5754 0.909 70 617o F 1.38 0.094 4.882 5728 0.978 70 617o F 0.83 0.003 0.409 5907 0 Acceptance A600MA 5% 5% 3840 psi 0.35 gpm Criterion SG-CDMP-20-23-NP March 2021 Revision 2 Page 42 of 90

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 a,c,e Figure 4-3. Watts Bar Unit 2 Maximum Depth POD Distribution for Circumferential ODSCC at HTS a,c,e Figure 4-4. Watts Bar Unit 2 Circumferential ODSCC Undetected Flaw Length Distribution SG-CDMP-20-23-NP March 2021 Revision 2 Page 43 of 90

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 a,c,e Figure 4-5. Watts Bar Unit 2 Simulated Circumferential ODSCC PDA Distribution a,c,e Figure 4-6. Watts Bar Unit 2 Circumferential ODSCC Maximum Depth Growth Distribution, 617oF SG-CDMP-20-23-NP March 2021 Revision 2 Page 44 of 90

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 a,c,e Figure 4-7. Watts Bar Unit 2 Circumferential ODSCC Length Growth Distribution, 617oF a,c,e Figure 4-8. Watts Bar Unit 2 Circumferential ODSCC PDA Growth Distribution, 617oF SG-CDMP-20-23-NP March 2021 Revision 2 Page 45 of 90

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 4.3.2 Axial ODSCC at Tubesheet Expansion Transitions A fully probabilistic full bundle analysis was performed using the Westinghouse FBM software package (Reference 25). The analysis assessed the SG performance criteria for POB and POL, burst pressure and accident induced leakage performance criteria for axial ODSCC flaws located at expansion transition and sludge pile regions over one full cycle of operation with a duration of 1.38 EFPY and for operation through to the planned mid-cycle outage beginning 09/15/2021 (0.83 EFPY).

A POD distribution for axial ODSCC flaws located at the top of the tubesheet and sludge pile was developed as input to the full probability analysis model. For axial ODSCC at these locations, the +POINT probe detection and sizing technique applied during inspections was ETSS I28424. A site-specific POD function for maximum flaw depth was developed using the EPRI MAPOD computer code (Reference 24). The MAPOD model [

]a,c,e to generate a site-specific noise-based POD curve for maximum flaw depth. The U2R3

[ ]a,c,e noise window applicable to axial degradation was used for the development of the POD curve. Figure 4-9 provides the results of the Watts Bar U2 specific MAPOD simulation for axial ODSCC at tubesheet expansion transitions for maximum depth. The POD function produces a 95th percentile maximum depth 95th percentile value of [ ]a,c,e and [ ]a,c,e at the th 50 percentile.

The fully probabilistic analysis uses flaw size distributions for assumed flaws that may not have been detected during the U2R3 inspection. The flaw size parameters for the undetected flaw population include maximum depth and length. The undetected flaw distributions describe the BOC flaw sizes to which the flaw growth is applied. The undetected flaw size distributions for each parameter were derived by the following methods:

The undetected maximum depth distribution was developed from the site-specific POD distribution (described above) [ ]a,c,e.

The undetected flaw total length distribution was derived from evaluation of the detected axial flaws located at the tubesheet expansion transition and sludge pile regions reported in U2R3. The largest observed axial extent of an axial flaw was 0.45 inch and was located within the sludge pile in the freespan. [ ]a,c,e was conservatively applied to describe the undetected length character of undetected flaws.

Flaw growth rate distributions are applied to the BOC flaw distributions for maximum depth and total length.

Re-analysis of historical data for axial flaws observed from all locations showed no precursor signals at the prior inspection. Consequently, a site-specific growth rate cannot be determined. In lieu of using site-specific growth distributions in this assessment, the Reference 5 typical default growth rate distributions were used for maximum depth and total length. A prorated growth rate based on [

]a,c,e is used for full-cycle OA durations. The OA for the duration to the mid-cycle outage will conservatively assume full power and temperature conditions.

The maximum to average depth shape factor is used by the FBM code to convert simulated maximum depths to an average depth basis so that the burst pressure can be calculated. Reference 5 defines this data and is described by [

]a,c,e. Since the average depth cannot exceed the maximum depth, a lower truncation of [ ] and an upper truncation of [

a,c,e

]a,c,e are used. This upper truncation is conservative since the axial ODSCC pulled tube database includes shape factors greater than [ ]a,c,e.

The structural to total length shape factor converts the simulated total flaw length to a structural equivalent average length basis so that the burst pressure can be calculated. A review of the axial ODSCC database SG-CDMP-20-23-NP March 2021 Revision 2 Page 46 of 90

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 shows [

]a,c,e (Reference 25). Based on benchmarking the model to the U2R3 results, the length shape factor was adjusted [ ]a,c,e was applied to conservatively bound the benchmarking results.

The number of undetected flaws assumed in the assessment was 6 in a single SG. This number of undetected flaws is judged to bound the number of undetected flaws in the limiting SG at U2R3 (SG-3) and new flaw initiations that may occur over one operating cycle. This assumption is more than the number of axial flaws at expansion transitions reported in all SGs during U2R3 (4 flaws) and doubles the number of flaws found in a single SG (3 flaws). Sensitivity simulations were performed for 10 flaws.

The inputs and assumptions to the fully probabilistic model were benchmarked to the Watts Bar U2R3 results for all axial flaws observed (4 flaws). The model conservatively bounded the burst pressure of the most limiting axial flaw at U2R3 at the expansion transitions and sludge pile locations.

The POB and POL results for the 6 and 10 undetected flaw assumptions are provided in Table 4-2. Five cases were evaluated for varying assumptions as provided in the table, including assumptions for cycle duration, temperature and number of undetected flaws. These results are all within the 5% performance criteria for burst and accident induced leakage probabilities. Additionally, the accident induced leakage satisfies the accident induced leakage limit of 1.0 gpm for all cases. The lower 5th percentile burst pressure also satisfies the minimum burst pressure requirement of 3840 psi for all cases. Therefore, axial ODSCC at the hot leg expansion transition and sludge pile regions meet the OA performance criteria for structural and leakage integrity for one full cycle of operation.

Table 4-2. Axial ODSCC at HTS FBM Simulation Results Summary Prob. of Prob. of Burst Leak Rate Number of Cycle Burst Leakage Pressure at at Lower Undetected Temperature Duration (POB) (POL) Lower 5% 5%

Flaws Assumption (EFPY) (%) (%) (psi) (gpm) 6 Prorated 1.38 0.096 0.071 5962 0 6 617o F 1.38 0.144 0.074 5873 0 6 617o F 0.83 0.030 0.013 6382 0 10 617o F 1.38 0.202 0.128 5541 0 10 617o F 0.83 0.054 0.015 6086 0 Acceptance A600MA 5% 5% 3840 psi 0.35 gpm Criterion SG-CDMP-20-23-NP March 2021 Revision 2 Page 47 of 90

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 a,c,e Figure 4-9. Watts Bar Unit 2 Maximum Depth POD Distribution for Axial ODSCC at HTS 4.3.3 Axial PWSCC at Expansion Transitions A full probabilistic full bundle analysis was performed using the Westinghouse FBM software package (Reference 25). The analysis assessed the SG performance criteria for POB and POL, burst pressure and accident induced leakage performance criteria for axial PWSCC flaws located at the expansion transition region over one full cycle of operation with a duration of 1.38 EFPY and for operation through to the planned mid-cycle outage beginning 09/15/2021.

A POD distribution for axial PWSCC flaws located at the top of the tubesheet was developed as input to the full probability analysis model. For axial PWSCC at this location, the +POINT probe detection and sizing technique applied during inspections was ETSS 20511.1. A site-specific POD function for maximum flaw depth was developed using the EPRI MAPOD computer code (Reference 24). The MAPOD model

[

]a,c,e to generate a site-specific noise-based POD curve for maximum flaw depth. The U2R3 noise distribution for the [ ]a,c,e noise window applicable to axial degradation was used for the development of the POD curve. Figure 4-10 provides the results of the Watts Bar Unit 2 specific MAPOD simulations for axial PWSCC at tubesheet expansion transitions for maximum depth. As shown in the figure, the [

]a,c,e. The [ ]a,c,e POD distribution produces a 95th percentile th a,c,e maximum depth 95 percentile value of [ ] and [ ]a,c,e at the 50th percentile.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 The fully probabilistic analysis uses flaw size distributions for assumed flaws that may not have been detected during the U2R3 inspection. The flaw size parameters for the undetected flaw population include maximum depth and length. The undetected flaw distributions describe the BOC flaw sizes to which the flaw growth is applied. The undetected flaw size distributions for each parameter were derived by the following methods:

The undetected maximum depth distribution was developed from the site-specific POD distribution (described above) [ ]a,c,e.

The undetected flaw total length distribution was derived from evaluation of the detected axial flaws from all observed locations and mechanisms reported in U2R3, as only a single axial PWSCC flaw was reported during U2R3. The largest observed axial extent of an axial flaw was 0.45 inch and was located within the sludge pile in the freespan. The axial PWSCC flaw reported during U2R3 was 0.11 inch in length. [ ]a,c,e was conservatively applied to describe the undetected length character of undetected flaws.

Flaw growth rate distributions are applied to the BOC flaw distributions for maximum depth and total length.

Only a single indication of axial PWSCC had been reported through U2R3. Consequently, a site-specific growth rate cannot be determined. In lieu of using site-specific growth distributions in this assessment, the Reference 5 recommended typical default growth rate distributions were used for maximum depth and total length. The growth rate distributions [ ]a,c,e to address benchmarking to the U2R3 indication. A prorated growth rate [

]a,c,e is used for full-cycle OA durations. The OA for the duration to the mid-cycle outage will conservatively assume full power and temperature conditions.

The maximum to average depth shape factor is used by the FBM code to convert simulated maximum depths to an average depth basis so that the burst pressure can be calculated. Reference 5 defines this data and is described by [

]a,c,e. Since the average depth cannot exceed the maximum depth, a lower truncation of [ ] and an upper truncation of [

a,c,e

]a,c,e are used. This upper truncation is conservative since the axial ODSCC pulled tube database includes shape factors greater than [ ]a,c,e. The shape factor derived for ODSCC is applicable to PWSCC.

The structural to total length shape factor converts the simulated total flaw length to a structural equivalent average length basis so that the burst pressure can be calculated. A review of the axial ODSCC database shows that the length shape factor [

]a,c,e. Based on benchmarking the model to the U2R3 results, the length shape factor was adjusted [

]a,c,e to conservatively bound the benchmarking results.

With a single axial PWSCC flaw being reported at Watts Bar Unit 2, a failure projection based on observed flaws cannot be performed. Therefore, the number of undetected flaws used in the assessment was assumed to be 2 in a single SG. This number of undetected flaws is judged to bound the number of undetected flaws at U2R3 and new flaw initiations that may occur over one operating cycle. This assumption doubles the number of axial PWSCC flaws at expansion transitions reported in all SGs during U2R3 (1 flaw). Sensitivity simulations were performed for 5 flaws.

The inputs and assumptions to the fully probabilistic model were benchmarked to the Watts Bar U2R3 results for all axial flaws observed (4 flaws). The model conservatively bounded the burst pressure of the most limiting axial PWSCC flaw at U2R3 at the expansion transition.

The POB and POL results for the 2 and 5 undetected flaw assumptions are provided in Table 4-3. Five cases were evaluated for varying assumptions as provided in the table, including assumptions for cycle duration, temperature and number of undetected flaws. These results are all within the 5% performance criteria for burst and accident induced leakage probabilities. Additionally, the accident induced leakage satisfies the SG-CDMP-20-23-NP March 2021 Revision 2 Page 49 of 90

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 accident induced leakage limit of 1.0 gpm for all cases. The lower 5th percentile burst pressure also satisfies the minimum burst pressure requirement of 3840 psi for all cases. Therefore, axial PWSCC at the hot leg expansion transition region meets the OA performance criteria for structural and leakage integrity for one full cycle of operation.

Table 4-3. Axial PWSCC at HTS FBM Simulation Results Summary Prob. of Prob. of Burst Number of Cycle Burst Leakage Pressure at Leak Rate Undetected Temperature Duration (POB) (POL) Lower 5% at Lower Flaws Assumption (EFPY) (%) (%) (psi) 5% (gpm) 2 Prorated 1.38 0.070 0.013 6395 0 2 617o F 1.38 0.106 0.021 6304 0 2 617o F 0.83 0.022 0.001 6855 0 5 617o F 1.38 0.246 0.049 5630 0 5 617o F 0.83 0.044 0.005 6223 0 Acceptance A600MA 5% 5% 3840 psi 0.35 gpm Criterion a,c,e Figure 4-10. Watts Bar Unit 2 Maximum Depth POD Distribution for Axial PWSCC at HTS 4.3.4 Axial ODSCC at TSP Intersections Excluded from GL 95-05 A full probability full bundle analysis was performed using the Westinghouse FBM software package (Reference 25). The analysis assessed the SG performance criteria for POB and POL, burst pressure and accident induced leakage performance criteria for axial ODSCC flaws at TSP intersections that are excluded from the GL 95-05 requirements, flaws over one full cycle of operation with a duration of 1.38 EFPY, and for operation through to the planned mid-cycle outage beginning 09/15/2021.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 The EPRI ETSS I28411 POD distribution for axial ODSCC flaws located at drilled hole TSP intersections was used as input to the full probability analysis model. This technique and POD are applicable for detection with the bobbin coil probe. In accordance with GL 95-05 and the pre-outage degradation assessment, all DSIs with mix residuals that could cause a bobbin signal to be missed or misread are required to be inspected with the +POINT probe. A 1-volt (Vpp) flaw from the bobbin coil has a flaw depth of [

]a,c,e using the I28411 data set correlations for 0.043 inch wall tubing. ETSS I28424 is the +POINT probe detection technique for axial ODSCC at drilled hole TSP intersections; this technique has a 95th percentile POD of [ ]a,c,e (Section 4.3.2). Therefore, the I28411 bobbin coil POD curve was truncated to a flaw depth of [ ]a,c,e to account for the additional inspection with the +POINT probe when determining the undetected flaw maximum depth.

The fully probabilistic analysis uses flaw size distributions for assumed flaws that may not have been detected during the U2R3 inspection. The flaw size parameters for the undetected flaw population include maximum depth and length. The undetected flaw distributions describe the BOC flaw sizes to which the flaw growth is applied. The undetected flaw size distributions for each parameter were derived by the following methods:

The undetected maximum depth distribution was developed from the site-specific POD distribution (described above) [

]a,c,e.

The undetected flaw total length distribution was derived from evaluation of the detected axial flaws at GL 95-05 excluded axial flaws reported in U2R3. The largest observed axial extent of an axial flaw within an excluded TSP intersection was 0.39 inch. [

]a,c,e was conservatively applied to describe the undetected length character of undetected flaws.

Flaw growth rate distributions are applied to the BOC flaw distributions for maximum depth and total length.

As all but three axial ODSCC flaws at TSP intersections were evaluated under the voltage-based GL 95-05 criteria, depth-based growth rates were not determined. Consequently, in lieu of using site-specific growth distributions in this assessment, the Reference 5 recommended conservative upper bound default growth distribution was used for maximum depth and total length. A prorated growth rate based on [

]a,c,e is used for full-cycle OA durations. The OA for the duration to the mid-cycle outage will conservatively assume full power and temperature conditions.

The maximum to average depth shape factor is used by the FBM code to convert simulated maximum depths to an average depth basis so that the burst pressure can be calculated. Reference 5 defines this data and is described by [

]a,c,e. Since the average depth cannot exceed the maximum depth, a lower truncation of [ ] and an upper truncation of [

a,c,e

]a,c,e are used. This upper truncation is conservative since the axial ODSCC pulled tube database includes shape factors greater than [ ]a,c,e.

The structural to total length shape factor converts the simulated total flaw length to a structural equivalent average length basis so that the burst pressure can be calculated. A review of the axial ODSCC database shows that the length shape factor [

]a,c,e (Reference 25). Therefore, [ ]a,c,e was applied.

The number of undetected flaws located at TSP intersections excluded from the requirements of GL 95-05 were determined through Weibull failure analysis of all DSIs reported at Watts Bar Unit 2 through U2R3 and projected to U2R4. [

]a,c,e SG-CDMP-20-23-NP March 2021 Revision 2 Page 51 of 90

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WESTINGHOUSE NON-PROPRIETARY CLASS 3

[

]a,c,e. This method estimated that 6 axial ODSCC flaws at excluded TSP intersections would be expected at U2R4. It was conservatively assumed that all flaws were located in one SG. Sensitivity simulations were performed for 10 flaws.

The inputs and assumptions to the fully probabilistic model were benchmarked to the Watts Bar U2R3 results for all axial flaws observed (3 flaws). The model conservatively bounded the burst pressure of the most limiting axial flaw at U2R3 at TSP intersections excluded from GL 95-05.

The POB and POL results for the 6 and 10 undetected flaw assumptions are provided in Table 4-4. Five cases were evaluated for varying assumptions as provided in the table, including assumptions for cycle duration, temperature, and number of undetected flaws. These results are all within the 5% performance criteria for burst and accident induced leakage probabilities. Additionally, the accident induced leakage satisfies the accident induced leakage limit of 1.0 gpm for all cases. The lower 5th percentile burst pressure also satisfies the minimum burst pressure requirement of 3840 psi for all cases. Therefore, axial ODSCC at the hot leg expansion transition and sludge pile regions meet the OA performance criteria for structural and leakage integrity for one full cycle of operation.

Table 4-4. Axial ODSCC at TSP Location Excluded from GL 95-05 FBM Simulation Results Summary Prob. of Prob. of Burst Leak Rate Number of Cycle Burst Leakage Pressure at at Lower Undetected Temperature Duration (POB) (POL) Lower 5% 5%

Flaws Assumption (EFPY) (%) (%) (psi) (gpm) 6 Prorated 1.38 0.091 0.053 5901 0 o

6 617 F 1.38 0.128 0.079 5822 0 6 617o F 0.83 0.015 0.007 6354 0 10 617o F 1.38 0.185 0.116 5517 0 o

10 617 F 0.83 0.027 0.009 6091 0 Acceptance A600MA 5% 5% 3840 psi 0.35 gpm Criterion 4.3.5 Circumferential ODSCC at Freespan Dings A fully probabilistic full bundle analysis was performed using the Westinghouse Full Bundle Model (FBM) software package (Reference 25). The analysis assessed the SG performance criteria for probability of burst (POB), probability of leakage (POL), burst pressure and accident induced leakage performance criteria for circumferential ODSCC flaws in freespan dings. The initial U2R3 inspection sample for this mechanism was 100% +POINT probe of the hot leg dings greater than and equal to 5 volts and 25% and all dings greater than and equal to 2 volts. The inspection scope was increased to 100% of the dings greater than and equal to 2 volts in SG-2 due to detecting two circumferential flaws. Scope expansion in the other SGs was not required for this mechanism. To address ding locations not inspected in U2R3, a two-cycle (2.739 EFPY)

OA is performed for postulated flaws that could have initiated at the beginning of Cycle 3. A separate OA was performed to address the OA duration over Cycle 3 through to the planned mid-cycle outage beginning 09/15/2021 (2.189 EFPY).

The fully probabilistic analysis begins with development of flaw detection of a POD distribution and distributions of undetected flaws. For circumferential ODSCC at freespan dings, the +POINT probe detection and sizing technique applied during inspections was ETSS 21410.1. This is the same technique that is used for detection of circumferential ODSCC at expansion transitions. The +POINT probe is a surface riding probe that reduces the effects of tube geometry deformation such as expansions or dings.

Therefore, the POD developed in Section 4.3.1 will be applied to circumferential ODSCC at freespan dings.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 Figure 4-3 provides the maximum depth POD for circumferential ODSCC at expansion transitions which is also applicable at freespan ding locations. The [ ]a,c,e POD function produces a 95th percentile th a,c,e maximum depth 95 percentile value of [ ] and [ ]a,c,e at the 50th percentile.

The fully probabilistic analysis uses flaw size distributions for assumed flaws that may not have been detected during the U2R3 inspection. The flaw size parameters for the undetected flaw population include maximum depth, length, and PDA. The undetected flaw distributions describe the BOC flaw sizes to which the flaw growth is applied. The undetected flaw size distributions for each parameter were derived by the following methods:

The undetected maximum depth distribution was developed from the site-specific POD distribution (described above) [ ]a,c,e.

The undetected flaw total length distribution was derived from a conservative assumption from the review of the circumferential ODSCC flaws observed during U2R3. The length of the two observed Unit 2 circumferential flaws at freespan dings were 24.6 degrees and 56.9 degrees. A [

]a,c,e provides a conservative assumption.

The undetected flaw PDA distribution was derived [

]a,c,e. This distribution provides a conservative assumption for circumferential flaws at ding locations as length of flaws at ding locations are blunted to the extent of the ding deformation. The resultant undetected flaw PDA distribution is described with a 95th percentile of [ ]a,c,e and a 50th percentile of [ ]a,c,e. Figure 4-5 provides the simulation results for the assumed undetected flaw PDA distribution.

Flaw growth rate distributions are applied to the BOC flaw distributions for maximum depth and total length.

Only two indications of circumferential ODSCC at ding locations had been reported through U2R3.

Consequently, a site-specific growth rate cannot be determined. In lieu of using site-specific growth distributions in this assessment, the Reference 6 recommended typical default growth distribution was used for maximum depth, total length, and PDA. A prorated growth rate based on [

]a,c,e is used for full-cycle OA durations. [

]a,c,e. The OA for the duration to the mid-cycle outage will conservatively assume full power and temperature conditions.

With two circumferential ODSCC flaws at freespan ding locations being reported at Watts Bar Unit 2, a failure projection based on observed flaws cannot be performed. Therefore, the number of undetected flaws used in the assessment was assumed to be 3 in a single SG. This number of undetected flaws is judged to bound the number of undetected flaws at U2R3 and new flaw initiations that may occur. This assumption is consistent with the fractional change from the Weibull failure analysis for circumferential ODSCC discussed in Section 4.3.1. Sensitivity simulations were performed for 6 flaws.

The inputs and assumptions to the fully probabilistic model were benchmarked to the Watts Bar U2R3 results for SG-3 (2 flaws). The model conservatively bounded the burst pressure of the most limiting circumferential flaw at U2R3 in SG-2 where 2 flawed tubes were reported.

The POB and POL results for the 3 and 6 undetected flaw assumptions are provided in Table 4-5. Five cases were evaluated for varying assumptions as provided in the table, including assumptions for cycle duration, temperature, and number of undetected flaws. These results are both within the 5% performance criteria for burst and accident induced leakage probabilities. Additionally, the accident induced leakage satisfies the accident induced leakage limit of 1.0 gpm for both cases. The lower 5th percentile burst pressure also satisfies the minimum burst pressure requirement of 3840 psi for both cases. Therefore, circumferential ODSCC at freespan ding locations meets the OA performance criteria for structural and leakage integrity for one full cycle of operation.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 Table 4-5. Circumferential ODSCC at Freespan Dings FBM Simulation Results Summary Prob. of Prob. of Burst Leak Rate Number of Cycle Burst Leakage Pressure at at Lower Undetected Temperature Duration (POB) (POL) Lower 5% 5%

Flaws Assumption (EFPY) (%) (%) (psi) (gpm) 3 Prorated 2.739 0.515 0.227 5991 0 o

3 617 F 2.739 0.580 0.267 5932 0 3 617o F 2.189 0.185 0.067 6303 0 6 617o F 2.739 1.208 0.549 5541 0.009 6 617o F 2.189 0.352 0.123 5971 0 Acceptance A600MA 5% 5% 3840 psi 0.35 gpm Criterion 4.3.6 Axial ODSCC at Freespan Dings A fully probabilistic full bundle analysis was performed using the Westinghouse FBM software package (Reference 25). The analysis assessed the SG performance criteria for POB and POL, burst pressure and accident induced leakage performance criteria for axial ODSCC flaws freespan dings. The initial U2R3 inspection sample for this mechanism was 100% +POINT probe of the hot leg dings greater than and equal to 5 volts and 25%, all dings greater than and equal to 2 volts and a 100% full-length inspection of all tubes.

The +POINT probe inspection scope was increased to 100% of the dings greater than and equal to 5 volts in SG-2 and SG-4 due to detecting two axial flaws. Scope expansion in the other two SGs was not required for this mechanism. To address dings not inspected in U2R3, a two-cycle (2.739 EFPY) OA is performed for postulated flaws that could have initiated at the beginning of Cycle 3. A separate OA was performed to address the OA duration over Cycle 3 through to the planned mid-cycle outage beginning 09/15/2021 (2.189 EFPY).

A POD distribution for axial ODSCC flaws located at freespan ding locations was developed as input to the full probabilistic analysis model. The inspection program for axial ODSCC at freespan dings included

+POINT probe and array probe inspection of dings 5-volts and bobbin probe inspection of dings <5-volts.

This degradation mechanism is applicable to dings of all voltage sizes. Therefore, the more limiting POD distribution of the probe types will be used for the OA evaluation.

The +POINT probe inspection of dings 5-volts used the ETSS 22401.1 inspection technique. This technique is an Appendix H technique and does not contain the necessary performance parameters for development of a POD distribution. This technique has the same set-up and normalization parameters as technique ETSS I28424 that was applied to detection of axial ODSCC at the tubesheet expansion transition (Reference 3). Both techniques are surface riding probes used for inspection of tube geometry deformations such as expansion transitions and dings. Therefore, the detection capabilities are expected to be similar.

This is demonstrated by review of the ETSS 22401.1 data set and the developed POD curve for ETSS I28424 (Figure 4-9). The data set for ETSS 22401.1 demonstrated that all flaws of [ ]a,c,e were a,c,e detected as compared to [ ] from ETSS I28424 shown in Figure 4-9.

The POD curve for ETSS I28424 is more conservative than the ETSS 22401.1 data set. Likewise, Reference 13 provided extension of the array probe to detection of axial ODSCC at dent and ding locations for [ ]a,c,e flaws. The result is also bounded by the ETSS I28424 POD curve shown in Figure 4-9 and Figure 4-11. The ETSS I28424 POD is applied to detection of axial ODSCC at freespan ding locations with dings 5-volts. This POD distribution produces a 95th percentile maximum depth 95th percentile value of [ ]a,c,e and [ ]a,c,e at the 50th percentile.

The bobbin coil inspection technique ETSS 10013.1 was applied to the detection of axial ODSCC at freespan dings that are less than 5-volts (Reference 3). A noise-based POD curve was developed using the MAPOD methodology (Reference 24) using the U2R3 hot leg freespan bobbin coil noise distribution and the ETSS 10013.1 data set. The resultant POD distribution is shown in Figure 4-11. The bobbin coil POD distribution SG-CDMP-20-23-NP March 2021 Revision 2 Page 54 of 90

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 produces a 95th percentile POD of [ ]a,c,e and a 50th percentile of [ ]a,c,e. Therefore, the more conservative ETSS I28424 +POINT probe POD distribution will be used in the OA for axial ODSCC at freespan dings.

The fully probabilistic analysis uses flaw size distributions for assumed flaws that may not have been detected during the U2R3 inspection. The flaw size parameters for the undetected flaw population include maximum depth and length. The undetected flaw distributions describe the BOC flaw sizes to which the flaw growth is applied. The undetected flaw size distributions for each parameter were derived by the following methods:

The undetected maximum depth distribution was developed from the site-specific POD distribution (described above) [ ]a,c,e.

The undetected flaw total length distribution was derived from evaluation of the detected axial flaws located at freespan dings reported in U2R3. The largest observed axial extent of an axial flaw was 0.29 inch. Cracking at ding locations are confined to the extent of the ding as the stress state that propagates the cracking diminishes as the crack nears the edge of the ding. [

]a,c,e was conservatively applied to describe the undetected length character of undetected flaws.

Flaw growth rate distributions are applied to the BOC flaw distributions for maximum depth and total length.

Only two indications of axial ODSCC at dings had been reported through U2R3. Consequently, a site-specific growth rate cannot be determined. In lieu of using site-specific growth distributions in this assessment, the Reference 5 recommended typical default growth distribution was used for maximum depth and total length. Based on benchmarking of this OA model to U2R3 observed flaws, the default typical growth rates for depth and length were increased by 10%. A prorated growth rate based on [

]a,c,e is used for full-cycle OA durations. The OA for the duration to the mid-cycle outage will conservatively assume full power and temperature conditions.

The maximum to average depth shape factor is used by the FBM code to convert simulated maximum depths to an average depth basis so that the burst pressure can be calculated. Reference 5 defines this data and is described [

]a,c,e. Since the average depth cannot exceed the maximum depth, a lower truncation of [ ] and an upper truncation of [

a,c,e

]a,c,e are used. This upper truncation is conservative since the axial ODSCC pulled tube database includes shape factors greater than [ ]a,c,e.

The structural to total length shape factor converts the simulated total flaw length to a structural equivalent average length basis so that the burst pressure can be calculated. A review of the axial ODSCC database shows that the length shape factor is [

]a,c,e (Reference 25). The shape of the flaw within the extent of the ding blunts the flaw length and tends to reduce the length shape factor. Therefore, the length shape factor was adjusted to [

]a,c,e and was applied to conservatively bound the benchmarking results.

With two axial ODSCC flaws being reported at Watts Bar Unit 2, a failure projection based on observed flaws cannot be performed. Therefore, the number of undetected flaws used in the assessment was assumed to be 3 in a single SG. This number of undetected flaws is judged to bound the number of undetected flaws at U2R3 and new flaw initiations that may occur over one operating cycle. This assumption consistent with the fractional change from the Weibull failure analysis for circumferential ODSCC discussed in Section 4.3.1. Sensitivity simulations were performed for 6 flaws.

The inputs and assumptions to the fully probabilistic model were benchmarked to the Watts Bar U2R3 results for all axial flaws observed (2 flaws). The model conservatively bounded the burst pressure of the most limiting axial ODSCC flaw at freespan ding locations during U2R3.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 The POB and POL results for the 3 and 6 undetected flaw assumptions are provided in Table 4-6. Five cases were evaluated for varying assumptions as provided in the table, including assumptions for cycle duration, temperature, and number of undetected flaws. These results are all within the 5% performance criteria for burst and accident induced leakage probabilities. Additionally, the accident induced leakage satisfies the accident induced leakage limit of 1.0 gpm for all cases. The lower 5th percentile burst pressure also satisfies the minimum burst pressure requirement of 3840 psi for all cases. Therefore, axial ODSCC at freespan ding locations meet the OA performance criteria for structural and leakage integrity for one full cycle of operation.

Table 4-6. Axial ODSCC at Freespan Dings FBM Simulation Results Summary Prob. of Prob. of Burst Leak Rate Number of Cycle Burst Leakage Pressure at at Lower Non-Detected Temperature Duration (POB) (POL) Lower 5% 5%

Flaws Assumption (EFPY) (%) (%) (psi) (gpm) 3 Prorated 2.739 1.192 0.689 4764 0 3 617o F 2.739 1.360 0.806 4687 0 3 617o F 2.189 0.565 0.289 5191 0 6 617o F 2.739 2.621 1.615 4230 0.052 6 617o F 2.189 1.115 0.585 4706 0 Acceptance A600MA 5% 5% 3840 psi 0.35 gpm Criterion a,c,e Figure 4-11. Watts Bar Unit 2 POD Distribution for Axial ODSCC at Freespan Dings <5v SG-CDMP-20-23-NP March 2021 Revision 2 Page 56 of 90

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 4.4 Cumulative Effect of Probabilistic Analyses The results described in Section 4.3 demonstrate that the tubing performance criteria is satisfied for POB and POL when evaluated separately for each existing ODSCC and PWSCC degradation mechanism when using fully probabilistic OA methods. Fully probabilistic methods were performed for the following existing degradation mechanisms:

Axial and circumferential ODSCC at expansion transitions Axial PWSCC at expansion transitions Axial ODSCC at TSP intersections excluded from GL 95-05 Circumferential ODSCC at Freespan Dings Axial ODSCC at Freespan Dings Revision 4 of the EPRI SG Integrity Assessment Guidelines (IAGL) provides guidance regarding the combination of probabilities. Section 8.3.3 of Reference 5 states that the POB and POL for each sub-mechanism are to be combined when the same mechanism is partitioned. There were no mechanisms that were partitioned in this OA. Additionally, for POL assessments, the total cumulative leakage is to be determined for all mechanisms combined. In this situation, the POL for each mechanism is combined to establish the total (cumulative) leakage probability for comparison to the accident induced leakage performance criteria (AILPC) requirement (i.e., <5%). The product of the individual survival probabilities will be required to satisfy the structural integrity and leakage integrity performance criteria as described above. The survival probability (POS) is defined as unity minus the probability of failure (1-PF) for each degradation mechanism.

Combination of POL for ODSCC/PWSCC Degradation Mechanisms Table 4-7 provides a summary of the POL values for each degradation mechanism that was evaluated through probabilistic methods. The POL values shown in the table represent the base case for the expected projected condition. The combined POL for the full cycle and mid-cycle operating durations are 4.885% and 1.452%, respectively. Both satisfy the <5% POL performance criteria and therefore satisfy the accident induced leakage performance criteria. Additionally, there is the combined predicted accident induced leakage at the lower 5th percent probability for the full cycle duration is 0.776 gpm and no leakage for operation to the mid-cycle outage. These results satisfy the site 1.0 gpm accident induced leakage limit, thereby satisfying the leakage integrity performance criteria.

The OA results from this assessment provides reasonable assurance that the SG performance criteria will be satisfied for operation from U2R3 through to the end of Cycle 4.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 Table 4-7. Combination of Probability of Leakage Results Full Cycle(1) Mid-Cycle(1)

Prob. of Leak Prob. of Leak Number Leakage Rate Leakage Rate Mechanism of Flaws (%) (gpm) (%) (gpm)

Circ. ODSCC at HTS 60 3.876 0.776 0.364 0 Axial ODSCC at HTS 6 0.071 0 0.013 0 Axial PWSCC at HTS 2 0.013 0 0.001 0 Axial ODSCC at TSP 6 0.053 0 0.007 0 Circ. ODSCC at FS Dings(2) 3 0.227 0 0.267 0 Axial ODSCC at FS Dings(2) 3 0.689 0 0.806 0 Combined POS (decimal) 0.9511 0.776 0.985 0 Combined POL (%) 4.885% 1.452%

POL Criteria <5% <5%

Combined POL Conclusion Acceptable Acceptable (1) Temperature Prorated growth rates were used for the Full Cycle OA category and a temperature of 617oF was used for the growth rates for the Mid-Cycle OA category.

(2) Due to inspection sampling strategy for freespan (FS) dings, a two-cycle OA duration was used for the Full Cycle and Mid-Cycle OA categories for both circumferential and axial ODSCC at freespan (FS) dings.

4.5 SG Secondary Side Foreign Objects During Watts Bar U2R3, there were a number of signals corresponding to PLPs located both at the top of the tubesheet and in the upper tube bundle. There was no tube degradation detected by eddy current coincident with the PLP indications. The PLP locations at the top of the tubesheet were visually inspected from the secondary side and, in the majority of cases, no foreign object was observed. Retrieval attempts were made when a foreign object was identified at the top of the tubesheet during investigation of a PLP on the secondary side.

In many cases during U2R3, visual inspection of PLP indications was not possible due to their location at the top of the TSPs within the tube upper bundle. Three considerations were made in order to address instances of PLPs in the tube upper bundle including eddy current data history review, previous foreign object visual inspection results, and the secondary side fluid flow fields during operation. The results of these considerations are shown in Attachment 5 for each of the PLP indications detected. As can be seen in Table A5-1, many of the PLP indications detected during Watts Bar U2R3 were trackable to the pre-service inspection and had corresponding visual inspections performed at that time. For indications that were truly new, the secondary side fluid velocities in the region were considered to be located a low flow region of the secondary side with a low propensity for foreign object wear to occur. Figure A5-1 provides a tubesheet map showing the tubes affected by PLPs. As a confirmation of this conclusion, a scoping level foreign object wear assessment was performed in Reference 7 and a machine turning typical of those found in the Watts Bar Unit 2 SGs would need to be greater than [

]a,c,e in order to cause wear exceeding the tube plugging limit over the course of 1.5 EFPY. None of the PLP indications combined with data review of adjacent tubes suggested that an object this size is present in the SG secondary side. As a result, no degradation in excess of the tube integrity limits is anticipated as a result of the PLP indications in the upcoming 1.5 EFPY estimated operating interval.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 The only objects known to be remaining in the SG secondary side at the top of tubesheet following Watts Bar U2R3 FOSAR are a small wire bristle lodged in hard scale in SG-1 and a metal object located between tubes in SG-4. This object was traced to being present in U2R1. These are the only two metallic objects known to be residing within the SG secondary side tubesheet region of all SGs. Additionally, seven pieces of small non-metallic sludge rocks were found in U2R3 and are incapable of causing tube wear due to their material characteristics.

A foreign object evaluation was performed and documented in Reference 26 that concludes that the objects remaining on the secondary side of the SGs are acceptable for at least one full operating cycle.

Therefore, it is projected that there will be no challenge to the Watts Bar Unit 2 SG structural and leakage integrity performance criteria relative to this degradation mechanism before the Watts Bar U2R4 refueling outage.

4.6 Operational Assessment Conclusions An Operational Assessment was performed that provided justification that the SG structural and leakage integrity is maintained through to U2R4 is expected to be acceptable through evaluation of all degradation mechanisms and bounds the Cycle 4 operating period through to the planned mid-cycle outage planned for 09/15/2021.

The OA for existing tube wear mechanisms at AVB and TSP supports demonstrated that structural and leakage integrity will be maintained through to the end of Cycle 4.

The OA for the existing stress corrosion crack mechanisms observed during U2R3 demonstrated that structural and leakage integrity will be maintain through to the end of Cycle 4. The degradation mechanisms evaluated in the OA included axial and circumferential ODSCC at the expansion transition region, axial PWSCC at the expansion transition region, axial and circumferential ODSCC at freespan dings, and axial ODSCC at TSP intersections that are excluded from application of the 95-05 alternate repair criteria.

Reference 22 and Reference 29 provide the OA for degradation addressed by GL 95-05.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 5.0 References

1. Steam Generator Management Program: Pressurized Water Reactor Steam Generator Examination Guidelines: Revision 8, EPRI, Palo Alto, CA: 2016. 3002007572.
2. Steam Generator Program Guidelines, NEI 97-06, Revision 3, January 2011.
3. TVA Work Order 121620833, Revision 0, Watts Bar U2R3 Steam Generator Degradation Assessment, October 2020. (Attached in EDMS).
4. Steam Generator Degradation Specific Management: Steam Generator Degradation Specific Management Flaw Handbook, Revision 2. EPRI, Palo Alto, CA: 2015. 3002005426.
5. Steam Generator Management Program: Steam Generator Integrity Assessment Guidelines, Revision 4. EPRI, Palo Alto, CA: 2016. 3002007571.
6. Steam Generator Management Program: Steam Generator In Situ Pressure Test Guidelines, Revision 5, EPRI, Palo Alto, CA: 2016. 3002007856.
7. Westinghouse Letter LTR-SGMP-17-97, Revision 0, Evaluation of Foreign Objects in the Secondary Side of the Watts Bar Unit 2 Steam Generators - Fall 2017 U2R1 Outage, November 2017.
8. Watts Bar Nuclear Plant Document 2-SI-68-907, Latest Revision, Steam Generator Tubing Inservice Inspection and Augmented Inspections.
9. Tennessee Valley Authority Document EDMS L18 20 1026 806, Revision 0, Watts Bar Nuclear Power Plant Unit 2 Use of Appendix H and I Qualified Techniques WBN-U2R3 Examination, April 2019. (Attached in EDMS)
10. Westinghouse Letter LTR-CDMP-19-38, Revision 0, Software Release Letter for Single Flaw Model Version 2.4, September 2019.
11. TVA Watts Bar Unit 2 Steam Generator Channel Head Cladding Indication Assessment, November 27, 2017. (Attached in EDMS)
12. Westinghouse Nuclear Safety Advisory Letter NSAL-12-1, Revision 1, Steam Generator Channel Head Degradation, October 2017.
13. Westinghouse Letter LTR-SGMP-17-95, Revision 1, Justification of X-PROBE Technique Extensions for Watts Bar Unit 2, April 2019.
14. Westinghouse Document SG-CDMP-19-10, Revision 0, Watts Bar U2R2 Steam Generator Condition Monitoring and Operational Assessment, May 2019.
15. U.S. Nuclear Regulatory Commission Generic Letter GL 95-05, Voltage Based Repair Criteria for Westinghouse Steam Generator Tubes Affected by Outside Diameter Stress Corrosion Cracking, August 1995.
16. U.S. Nuclear Regulatory Commission Information Notice 97-26, Degradation in Small-Radius U-Bend Regions of Steam Generator Tubes, May 1997.
17. Westinghouse Letter LTR-SGMP-12-9, Revision 5, Evaluation of Foreign Objects Identified in the Watts Bar Unit 2 Steam Generators, March 2014.

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WESTINGHOUSE NON-PROPRIETARY CLASS 3

18. Westinghouse Document SG-01-03-002, Revision 0, Circumferential ODSCC Depth Profiling Method for Hardroll Expansion Joints, Profiling Analysis Guidelines. March 2001.
19. Westinghouse Calculation Note CN-SGDA-02-93, Revision 0, Percent Degraded Area (PDA)

Sizing Uncertainties for Circumferential ODSCC in Hardroll Expansions, May 2002.

20. Westinghouse Document WCAP-13084, Revision 0, Tubesheet Region Tube Alternate Plugging (F*) Criterion for the Tennessee Valley Authority Watts Bar Units 1 and 2 Nuclear Power Plant Steam Generators, October 1991.
21. U.S. Nuclear Regulatory Commission, Watts Bar Nuclear Plant, Unit 2 - Issuance of Amendment Regarding Application to Revise Technical Specifications for Use of Voltage-Based Alternate Repair Criteria in Accordance with Generic Letter 95-05, June 3, 2019. (ADAMS Accession No. ML19063B721).
22. Westinghouse Letter LTR-CDMP-20-40, Revision 1, Watts Bar Unit 2 Refueling Outage 3 Steam Generator Alternate Repair Criteria Generic Letter 95-05 Return to Power Report, November 2020.
23. Westinghouse Document SG-00-01-001, Revision 0, Watts Bar Unit 1 Technical Justification for License Amendment for Implementing NRC Generic Letter GL 95-05 Voltage Based Repair Criteria Steam Generator Tube ODSCC, January 2000.
24. EPRI Computer Software 3002010334, Steam Generator Management Program: Model Assisted Probability of Detection Using R (MAPOD-R) Version 2.1, 2017.
25. Westinghouse Letter LTR-CDMP-20-33, Revision 0, Software Release Letter for Full Bundle Model, Version 2.3 on the Windows 10 System State, October 2020.
26. Westinghouse Letter LTR-CECO-20-100, Revision 0, Evaluation of Foreign Objects in the Secondary Side of the Watts Bar Unit 2 Steam Generators - Fall 2020 U2R3 Outage, November 2020.
27. Tennessee Valley Authority Document CNL-19-082, License Amendment Request for Measurement Uncertainty Recapture Power Uprate (WBN-TS-19-06), October 2019. (Attached in EDMS).
28. Westinghouse Calculation Note CN-SGDA-00-29, Revision 0, Watts Bar 1.4% Uprate Thermal-Hydraulic and U-bend Vibration Evaluations, May 2000.
29. Westinghouse Report SG-CDMP-21-1, Revision 0, Condition Monitoring and Operational Assessment: GL 95-05 Alternate Repair Criterion End of Cycle 3 90 Day Report Watts Bar 2, February 2021.

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      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Attachment 1 - Watts Bar U2R3 As-Implemented SG Inspection Scope um WATTSBAR2 S/G EC INSPECTION STATUS Base Scope Exam Prog rams Exams U2R3 Exams Outst anding Analyzed  % 'I, Westql'lluse Tub.s Acquired Sl11c* Lal SIG Exam n!l!e Programmed Acgulred Retests & Coml!l&te Acqu ired Coml!l&te Bllwl 1 610 CL Full Leoglh Bobbin Exams@ 50 IPS 4198 4198 0 4198 100.00*,1, 100.00% 0 1 .610 CL Low Row Bobbin Exams@ 24 IPS 451 451 0 451 100.00% 100.00% 0 1 610 HL Low Row Bobbin Exams@ 24 IPS 451 451 0 451 100.00% 100.00% 0 1 ,580 UB RPC R I-R4 U-8end EJ<Bms @0 4 IPS/900 RPM 461 461 D 461 100.00',1, 100.00% 0 1 .610 HL RPC Tubesheel Exams@ 0.7 IPS / *1500 RPf,,I 4649 4649 0 4649 100.00% 100.00% 0 1 .610 CL Arrav SlraiQhl Section Exams@ 40 IPS 2701 2701 0 2701 100.00% 100.00% 0 1 Total Tests SG 1 Base Scope Programs 12911 12911 0 12911 100.00% 100.00% 0 2 610 CL FUii Length Bobbin Exams@50 IPS 4190 4190 0 4190 100.00% 100.00% 0 2 610 CL Low Row Bobbin Exams@ 24 IPS 450 450 0 450 100.00',1, 100.00% 0 2 610 HL Low Row Bobbin Exams@ 24 IPS 450 450 0 450 100.00% 100.00'I. 0 2 .580 UB RPC Rt-R4 U-8end Exams@0.4 IPS/900 RPM 450 450 0 450 100.00% 100.00% 0 2 .610 HL RPC T<besheel Exams@ 0 7 IPS 1 1500 RPM 4640 4640 0 4640 100.00% 100.00% 0 2 .610 CL Array S1ra19hl Section Exams@ 40 IPS 2676 2676 0 2676 100.00% 100.00% 0 2 Tot al Tests SO 2 Base Scope Programs 12856 12856 0 12856 100.00% 100.00% 0 3 610 CL FUii Length Bobbin Exams@ 50 IPS 4206 4206 0 4206 100.00',1, 100.00% 0 3 610 CL Low Row Bobbin Exams@ 24 IPS 454 454 0 454 100.00% 100.00% 0 3 610 HL Low Row Bobbin Exams@ 24 IPS 454 454 0 454 100.00% 100.00% 0 3 580 UB RPC R1 -R4 LI.Send Exams@0 4 IPS/900 RPM 454 454 0 454 100.00% 100.00% 0 3 .610 HL RPC Ttilesheel Exams@ 0 7 IPS I 1500 RPM 4660 4660 0 4660 100.00'/4 100.00% 0 3 .610 CL Array SlraIghl Section Exams@ 40 IPS 2686 2686 0 2686 100.00% 100.00% 52 3 Total Tests SG 3 Base Scope Programs 12914 12914 0 12914 100.00% 100.00% 52 4 610 CL Full Length Bobbtn Exams@ 50 IPS 4199 4199 0 4199 100.00% 100.00% 0 4 .610 CL Low Row Bobbin Exams@ 24 IPS 454 454 0 454 100.00'/4 100.00% 0 4 610 HL Low Row Bobbtn Exams@ 24 IPS 454 454 0 454 100.00*,1, 100.00% 0 4 .580 UB RPC Rl *R4 U-8end Exams@0.4 IPS/900 RPIII 454 454 0 454 100.00% 100.00% 0 4 .610 HL RPC TubeSr.eet Exams@ 0.7 IPS / 1500 RPf,,1 4653 4653 0 4653 100.00'/4 100.00% 0 4 .610 CL Array Slm19hl Section Exems@ 40 IPS 2649 2649 0 2649 100.00'/4 100.00% 10 4 Total Tests SG 4 Base Scope Program s 12863 12863 0 12863 100.00% 100.00% 10 ALL Combined Tot al All Tests Base Scope Programs 515<< 51544 0 515<< 100.00% 100.00%

Diagnostic Exams for B obbln /A rralt'. Indications !Seeclal Interest Additional Scol!*l Tubu A.cq1,dr*d Exams Exams Outstanding Analyzed  % 3/4 s rnuL.ais1 SIG Exam Type Programmed Acqu i red Retests & Comelete Acquired Comelete Bllwl 1 .500 HL/CL Gl/G4 Ghent Probe SI 4 4 0 4 100.00*,1, 100.00% 0 1 .610 HLICL 3C-RPC Straight Secbon SI 905 905 0 905 100.00% 100.00% 12 1 610 H L/CL Array SI 199 199 0 199 100.00% 100.00% 0 1 580 HL/CL UB-RPC SI 23 23 0 23 100.00% 100.00% 5 1 Total Tests SG 1 Special Interest Programs 1131 1131 0 1131 100.00" 100.00% 17 2 590 H L/CL GlIG4 Ghent Probe SI 5 5 0 5 100.00% 100.00% 0 2 610 H CL 3C-RPC StroIghl Section SI 930 930 0 930 100.00*,1, 100.00% 6 2 .610 HL/CL Arrey SI 210 210 0 210 100.00% 100.00% 0 2 .560 H l.JCL UB-RPC SI 10 10 0 10 100.00% 100.00% 0 2 I 00", ONT/ONG SI Expansion 582 582 0 582 100.00% 100.00% 123 2 Total Tests SO 2 Special Interest Programs 1737 1737 0 1737 100.00" 100.00% 129 3 590 H CL Gl/G4 Ghent Probe SI 3 3 0 3 100.00% 100.00% 0 3 610 H L/CL 3C-RPC Stra,ghl Secbon SI 649 649 0 649 100.00% 100.00'1'. 9 3 .610 HL/CL Array SI 80 80 0 80 100.00% 100.00% 0 3 580 HL/CL UB-RPC SI 9 9 0 9 100.00% 100.00% 0 3 Total Tests SG 3 Special Interest Programs 741 741 0 741 100.00" 100.00% 9 4 .590 HL/CL G3IG4 Ghent Probe SI 1 1 0 1 100.00*,1, 100.00% 0 4 610 HLiCL 3C-RPC 1roIght aotlonSI 353 363 0 353 100.00% 100.00% 16 4 610 HUCL Array SI 87 87 0 87 100.00*,1, 100.00% 0 4 580 HLICL UB-RPC SI 7 7 0 7 100.00% 100.00% 0 4 Total Tests SG 4 Special Interest Programs 448 448 0 448 100.00% 100.00% 16 ALL Comb ined Total All Special Interest Programs 4057 4057 0 4057 100,00% 100.00% 16 SG-CDMP-20-23-NP March 2021 Revision 2 Page 62 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Inspect ion Summary Exams Exams Outstanding Analyzed 3/4 3/4 SIG Combined Total All Tests and All Programs Programmed Acqu ired Retests & Comelete Acqu ired Comelete 1 Tota l Tests : Base and Diagnostic Tests 14042 14042 0 14042 100.00% 100.00%

2 Tota l Tests ; Base and Diagnostic Tests 14593 14593 0 14593 100.00% 100.00%

3 Tota l Tes ts: Base and Diagnostic Tests 13655 13655 0 13655 100.00% 100.00%

4 Tota l Tests; Base and Diagnostic Tests 13311 13311 0 13311 100.00% 100.00%

Combined Total All Tests and All Programs 55601 55601 0 5560 1 100.00% 100.00%

NOTE: Exams evaluated are counted when through the resolution process.

Additional Information Confl rmed Tubes to be Pluaaed Tota l Repair Candidate (:>40%: Array/RPC I-Codes) 8 22 120 36 186 Preventative I Customer Dec ision Tube to Plug 1 0 2 0 3 Tota l New Plugged Tubes 9 22 122 36 189 Tota l Prior Pluaaed Tubes 25 34 14 21 94 Total Committed Plugged Tubes 34 56 136 57 283

,.., , ** _ ... 1- ..... - .... : ....... C't ... , , . .. Hot Leg Cold leg SIG 1 Closed Out Closed Out SIG2 Closed Out Closed Out SIG3 Closed Out Closed Out S/G4 Closed Out Closed Out lnspec1lon Notes:

Lost ~ 9 hrs due to loss of vacuums and platform decon Lost~ 10.5 hrs due to cavity overflow SG-CDMP-20-23-NP March 2021 Revision 2 Page 63 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Attachment 2 - Watts Bar U2R3 SG Tube Structural and Condition Monitoring Limits Table A2-1. Watts Bar U2R3 SG Tube Structural and Condition Monitoring Limits Degradation Mechanism Plugging Structural Limit Condition Monitoring Limit Existing Volumetric Indications due to 58% TW Tube Fabrication and 40% TW 78% TW for 0.5 inch Installation Reference 3 Figure 8-1 66% TW Wear at 76% TW 40% TW for 0.6 inch AVBs for 0.6 inch Reference 3 Figure 8-2 64% TW Wear at 74% TW 40% TW for 0.75 inch Tube Support Plates for 0.75 inch Reference 3 Figure 8-3 Axial/Circumferential Ax 0.45 inch Ax Reference 3 Figure 8-5 Plug on Detection ODSCC at the TTS Circ 295° Circ 175° (2) / 48.8 PDA(2)

Axial ODSCC Plug on Detection 0.45 inch Reference 3 Figure 8-5 at Tube Support Plates Axial PWSCC at the TTS Plug on Detection Ax 0.45 inch Ax Reference 3 Figure 8-5 Ax 0.45 inch Ax Figure 8-5 ODSCC at Tube Dents and Dings Plug on Detection Circ 295° Circ 175° (2) / 48.8 PDA(2)

Potential 58% TW Wear due to 78% TW 40% TW for 0.5 inch Foreign Objects for 0.5 inch Reference 3 Figure 8-1 61% TW 69% TW Tube-to-Tube Contact Wear 40% TW for 2.0 inch for 2.0 inch Reference 3 Figure 8-4 58% TW 78% TW OD Pitting of the Tube Material Plug on Detection for 0.5 inch for 0.5 inch Reference 3 Figure 8-1 Circumferential PWSCC at TTS Plug on Detection Circ 281° Circ 274° Axial ODSCC Plug on Detection Ax 0.45 inch Ax Reference 3 Figure 8-5 at the TTS Axial and Circumferential Ax 0.45 inch Ax Reference 3 Figure 8-5 PWSCC in the Plug on Detection Circ 295° Circ 175° Low Row U-bends SCC at Tube Bulges and Ax 0.45 inch Ax Reference 3 Figure 8-5 Plug on Detection Overexpansions Circ 295° Circ 175° (2)

Axial ODSCC in the Freespan Plug on Detection 0.45 inch Reference 3 Figure 8-5 ODSCC at Dents and Dings Ax 0.45 inch Ax Reference 3 Figure 8-5 Plug on Detection Coincident with MBM Circ 295° Circ 175° / 48.8 PDA(2)

Note 1: The structural limits, Condition Monitoring limits and applicable ETSSs for each degradation mechanism are further discussed in the Reference 3 Degradation Assessment.

Note 2: CM limits determined from reanalysis of the EPRI TR-107197 dataset for hardroll expansions. Refer to Table A2-2 for mean regression and standard error.

SG-CDMP-20-23-NP March 2021 Revision 2 Page 64 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Table A2-2. Updated NDE Sizing Technique Regression and Standard Error Technique NDE Sizing Qualification Probe Structural Sizing Technique a,c,e Technique Mechanism Type Parameter Regression Standard Error Circumferential Maximum Depth TR-107197 ODSCC at Hardroll +POINT Length Expansions PDA LTR-CDME-07-163 Axial ODSCC +POINT Total Length SG-CDMP-20-23-NP March 2021 Revision 2 Page 65 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Attachment 3 - Watts Bar U2R3 Tube Plug and Stabilization Listing Table A3-1: Watts Bar U2R3 Tube Plug and Stabilization List for SG-1 Count SGID Row Col Ind Locn Inch1 Stabilizer(1) Reason 1 1 44 26 SAI H02 0.03 - 95-05,DSI>1v Confirmed 2 1 44 30 SCI HTS -0.02 Hot Leg Circ ODSCC at HTS 3 1 41 39 SCI HTS -0.17 Hot Leg Circ ODSCC at HTS 3 1 41 39 MAI H03 -0.01 - 95-05,DSI>1v Confirmed 4 1 4 57 SCI HTS -0.05 Hot Leg Circ ODSCC at HTS 5 1 39 63 TBP - Prevent - ID Chatter 6 1 4 65 SCI HTS -0.03 Hot Leg Circ ODSCC at HTS 7 1 3 70 SCI HTS -0.04 Hot Leg Circ ODSCC at HTS 8 1 30 77 SCI HTS -0.16 Hot Leg Circ ODSCC at HTS 9 1 7 107 SAI H02 0.15 - 95-05,DSI>1v Confirmed Note 1: 86-inch stabilizer installed SG-CDMP-20-23-NP March 2021 Revision 2 Page 66 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Table A3-2: Watts Bar U2R3 Tube Plug and Stabilization List for SG-2 Count SGID Row Col Ind Locn Inch1 Stabilizer(1) Comment 1 2 17 13 MAI H02 0.11 - 95-05, DSI>1 Confirmed 2 2 2 28 SAI H03 0 - 95-05, DSI>1 Confirmed 3 2 4 31 SAI H02 0 - 95-05, DSI>1 Confirmed 4 2 7 44 SAI H02 -0.01 - 95-05, DSI>1 Confirmed 5 2 2 49 SAI H03 0.01 - 95-05, DSI>1 Confirmed 6 2 44 52 MAI H03 0.02 - 95-05, DSI>1 Confirmed 7 2 40 53 DSV H03 0.07 - 95-05 DSI>URL 8 2 7 58 SCI H02 -1.95 Hot Leg Circ Freespan Ding 9 2 19 62 SAI H02 0.27 - 95-05, DSI>1 Confirmed 10 2 42 62 SAI H03 0 - 95-05, DSI>1 Confirmed 11 2 45 65 SCI HTS -0.06 Hot Leg Circ ODSCC HTS 12 2 44 66 SAI H02 0.07 - 95-05, DSI>1 Confirmed 13 2 27 67 SAI H04 0 - 95-05, DSI>1 Confirmed 14 2 31 73 SAI H02 0.11 - 95-05, DSI>1 Confirmed 15 2 30 78 SAI H02 0 - 95-05, DSI>1 Confirmed 16 2 9 86 SAI H02 1.27 - Axial ODSCC Freespan Ding 17 2 22 94 SAI H02 -0.01 - 95-05, DSI>1 Confirmed 18 2 17 100 SAI HTS 0.04 - Axial PWSCC HTS 19 2 20 102 SAI H03 0.03 - 95-05, DSI>1 Confirmed 20 2 29 103 MAI H03 -0.04 - 95-05, DSI>1 Confirmed 21 2 26 104 SAI H03 0.02 - 95-05, DSI>1 Confirmed 22 2 17 109 SCI C14 -1.99 Cold Leg(2) Circ Freespan Ding Note 1: 86-inch stabilizer installed Note 2: 305-inch stabilizer installed SG-CDMP-20-23-NP March 2021 Revision 2 Page 67 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Table A3-3: Watts Bar U2R3 Tube Plug and Stabilization List for SG-3 Count SGID Row Col Ind Locn Inch1 Stabilizer(1) Reason 1 3 2 112 SAI H03 0.02 - 95-05 DSI>1 Confirmed 2 3 3 92 SAI H02 0.08 - 95-05 DSI>1 Confirmed 109 DSV H03 0.05 - 95-05 DSI >URL 3 3 4 109 SAI H02 0 - 95-05 DSI>1 Confirmed 4 3 5 25 SAI H02 0.04 - 95-05 DSI>1 Confirmed 5 3 5 51 MAI H04 -0.08 - 95-05 DSI>1 Confirmed 6 3 5 96 SCI HTS -0.12 Hot Leg Circ ODSCC HTS 7 3 5 106 SAI H03 -0.03 - 95-05 DSI>1 Confirmed 8 3 5 107 MAI H02 0.08 - 95-05 DSI>1 Confirmed 9 3 6 21 SCI HTS -0.02 Hot Leg Circ ODSCC HTS 10 3 6 91 SAI H02 -0.04 - 95-05 DSI>1 Confirmed 11 3 7 60 MAI H03 0.12 - 95-05 DSI>1 Confirmed 12 3 7 62 DSV H02 -0.09 - 95-05 DSI>URL 13 3 7 107 SAI H03 -0.08 - 95-05 DSI>1 Confirmed 14 3 7 112 SAI H02 0 - 95-05 DSI>1 Confirmed 15 3 8 46 SAI H02 0.08 - 95-05 DSI>1 Confirmed 16 3 8 53 MAI H03 0.05 - 95-05 DSI>1 Confirmed 17 3 8 55 SAI H02 -0.05 - 95-05 DSI>1 Confirmed 18 3 8 92 SAI H02 0.04 - 95-05 DSI>1 Confirmed 19 3 9 9 DSV H02 0.12 - 95-05 DSI>URL 20 3 9 70 SCI HTS -0.03 Hot Leg Circ ODSCC HTS 21 3 9 73 SAI H03 0.03 - 95-05 DSI>1 Confirmed SCI HTS -0.11 Hot Leg Circ ODSCC HTS 22 3 9 98 MAI H02 -0.06 - 95-05 DSI>1 Confirmed 23 3 10 78 SCI HTS -0.15 Hot Leg Circ ODSCC HTS 24 3 11 109 MAI H02 0.03 - 95-05 DSI>1 Confirmed 25 3 12 67 MCI HTS -0.08 Hot Leg Circ ODSCC HTS 26 3 12 104 MAI H02 0.06 - 95-05 DSI>1 Confirmed 27 3 12 105 SCI HTS -0.11 Hot Leg Circ ODSCC HTS 28 3 12 111 DSV H02 0.07 - 95-05 DSI>URL 29 3 13 43 SAI H02 -0.09 - 95-05 DSI>1 Confirmed 30 3 13 71 MAI H03 0.1 - 95-05 DSI>1 Confirmed 31 3 13 88 SCI HTS -0.09 Hot Leg Circ ODSCC HTS 32 3 13 110 MAI H02 0.09 - 95-05 DSI>1 Confirmed 33 3 13 112 SAI H02 -0.03 - 95-05 DSI>1 Confirmed 34 3 14 7 DSV H02 -0.02 - 95-05 DSI>URL 35 3 14 55 SCI HTS -0.15 Hot Leg Circ ODSCC HTS 36 3 14 57 SCI HTS -0.17 Hot Leg Circ ODSCC HTS SG-CDMP-20-23-NP March 2021 Revision 2 Page 68 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Table A3-3: Watts Bar U2R3 Tube Plug and Stabilization List for SG-3 37 3 14 91 MCI HTS -0.05 Hot Leg Circ ODSCC HTS 38 3 14 92 MAI H02 -0.02 - 95-05 DSI>1 Confirmed 39 3 14 98 SCI HTS -0.08 Hot Leg Circ ODSCC HTS 40 3 14 99 SCI HTS -0.1 Hot Leg Circ ODSCC HTS 41 3 14 101 SCI HTS -0.05 Hot Leg Circ ODSCC HTS 42 3 14 108 MAI H02 -0.03 - 95-05 DSI>1 Confirmed 43 3 14 110 MAI H02 0.01 - 95-05 DSI>1 Confirmed 44 3 14 111 MAI H03 0.03 - 95-05 DSI>1 Confirmed 45 3 15 82 SCI HTS -0.04 Hot Leg Circ ODSCC HTS 46 3 16 49 SAI H02 -0.14 - 95-05 DSI>1 Confirmed 47 3 16 71 SCI HTS -0.15 Hot Leg Circ ODSCC HTS 48 3 16 111 MAI H02 -0.1 - 95-05 DSI>1 Confirmed 49 3 17 5 MAI H02 0.03 - 95-05 DSI>1 Confirmed 50 3 17 24 MAI H02 -0.05 - 95-05 DSI>1 Confirmed 51 3 17 37 SAI H03 0 - 95-05 DSI>1 Confirmed 52 3 17 41 MAI H02 0 - 95-05 DSI>1 Confirmed 53 3 17 44 SCI HTS -0.04 Hot Leg Circ ODSCC HTS 54 3 17 46 DSV H02 -0.12 - 95-05 DSI>URL 55 3 17 47 DSV H02 0 - 95-05 DSI>URL 56 3 17 54 DSV H01 0.09 - 95-05 DSI>URL 57 3 18 92 MAI H02 0.07 - 95-05 DSI>1 Confirmed 58 3 18 94 MAI H02 0.09 - 95-05 DSI>1 Confirmed 59 3 18 101 SAI H02 0.03 - 95-05 DSI>1 Confirmed 60 3 18 108 DSV H02 0 - 95-05 DSI>URL 61 3 18 109 MAI H02 0.03 - 95-05 DSI>1 Confirmed 62 3 18 110 MAI H03 0.13 - 95-05 DSI>1 Confirmed 63 3 19 10 MAI H02 0 - 95-05 DSI>1 Confirmed 64 3 19 57 SCI HTS -0.09 Hot Leg Circ ODSCC HTS 65 3 19 89 MAI H02 0.12 - 95-05 DSI>1 Confirmed 66 3 20 78 SAI H02 0.04 - 95-05 DSI>1 Confirmed 67 3 21 9 SAI H02 0.14 - 95-05 DSI>1 Confirmed 68 3 21 37 SAI H01 0.13 - 95-05 Excluded Tube 69 3 21 38 MAI H02 -0.03 - 95-05 DSI>1 Confirmed 70 3 21 56 SCI HTS -0.04 Hot Leg Circ ODSCC HTS 71 3 21 106 MAI H02 0 - 95-05 DSI>1 Confirmed 72 3 22 62 SCI HTS -0.05 Hot Leg Circ ODSCC HTS 73 3 22 66 SCI HTS -0.1 Hot Leg Circ ODSCC HTS 74 3 22 74 MAI H03 0.11 - 95-05 DSI>1 Confirmed 75 3 22 77 MAI H02 0.03 - 95-05 DSI>1 Confirmed 76 3 22 84 SCI HTS -0.11 Hot Leg Circ ODSCC HTS SAI HTS 0.5 - Axial ODSCC HTS 77 3 23 56 MCI HTS -0.02 Hot Leg Circ ODSCC HTS SG-CDMP-20-23-NP March 2021 Revision 2 Page 69 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Table A3-3: Watts Bar U2R3 Tube Plug and Stabilization List for SG-3 78 3 23 66 SAI HTS 0.2 - Axial ODSCC HTS 79 3 23 85 SCI HTS -0.04 Hot Leg Circ ODSCC HTS 80 3 23 93 SAI H02 0.09 - 95-05 DSI>1v Confirmed 81 3 24 65 SAI HTS 0.6 - Axial ODSCC HTS 82 3 25 60 SCI HTS -0.23 Hot Leg Circ ODSCC HTS 83 3 25 94 SAI H03 0.21 - 95-05 DSI>1v Confirmed 84 3 25 96 SAI H03 0.12 - 95-05 DSI>1v Confirmed 85 3 26 45 SCI HTS -0.1 Hot Leg Circ ODSCC HTS 86 3 26 71 SCI HTS -0.09 Hot Leg Circ ODSCC HTS 87 3 27 47 MAI H01 0.11 - 95-05 Excluded Tube 88 3 27 48 MAI H02 -0.03 - 95-05 DSI>1v Confirmed 89 3 28 27 MAI H03 -0.01 - 95-05 DSI>1v Confirmed 90 3 29 21 SCI HTS -0.1 Hot Leg Circ ODSCC HTS 91 3 32 57 SCI HTS -0.05 Hot Leg Circ ODSCC HTS 92 3 33 81 MAI H02 -0.01 - 95-05 DSI>1v Confirmed 93 3 35 18 SAI H02 -0.05 - 95-05 DSI>1v Confirmed 94 3 35 25 MAI H02 0 - 95-05 DSI>1v Confirmed 95 3 37 65 MAI H02 -0.01 - 95-05 DSI>1v Confirmed 96 3 38 56 MAI H02 0.19 - 95-05 DSI>1v Confirmed 59 MCI HTS -0.04 Hot Leg Circ ODSCC HTS 97 3 38 59 MAI H02 0.2 - 95-05 DSI>1 Confirmed 98 3 39 28 SCI HTS -0.05 Hot Leg Circ ODSCC HTS 99 3 40 64 MCI HTS -0.05 Hot Leg Circ ODSCC HTS 100 3 41 71 SCI HTS -0.1 Hot Leg Circ ODSCC HTS 101 3 43 25 SCI HTS -0.08 Hot Leg Circ ODSCC HTS 102 3 44 26 SCI HTS -0.05 Hot Leg Circ ODSCC HTS 103 3 45 28 SCI HTS -0.08 Hot Leg Circ ODSCC HTS 104 3 45 38 SCI HTS -0.03 Hot Leg Circ ODSCC HTS 105 3 45 47 SAI H02 -0.05 - 95-05 DSI>1v Confirmed 106 3 45 50 MAI H02 0.09 - 95-05 DSI>1v Confirmed 107 3 45 54 MAI H02 0.16 - 95-05 DSI>1v Confirmed 108 3 46 54 MAI H02 0.18 - 95-05 DSI>1v Confirmed 109 3 46 74 MCI HTS -0.14 Hot Leg Circ ODSCC HTS 110 3 46 79 MAI H03 0.09 - 95-05 DSI>1v Confirmed 111 3 46 83 SCI HTS -0.05 Hot Leg Circ ODSCC HTS 112 3 46 87 SAI H02 -0.04 - 95-05 DSI>1v Confirmed 113 3 47 73 SCI HTS -0.07 Hot Leg Circ ODSCC HTS MAI H04 -0.01 - 95-05 Excluded Tube 114 3 47 87 SAI H02 0 - 95-05 DSI>1v Confirmed 115 3 48 52 SAI H02 0.05 - 95-05 DSI>1v Confirmed 116 3 48 57 DSV H02 0.09 - 95-05 DSI>URL 117 3 49 31 SCI HTS -0.04 Hot Leg Circ ODSCC HTS SG-CDMP-20-23-NP March 2021 Revision 2 Page 70 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Table A3-3: Watts Bar U2R3 Tube Plug and Stabilization List for SG-3 118 3 49 38 MCI HTS -0.05 Hot Leg Circ ODSCC HTS 119 3 49 79 SCI HTS -0.04 Hot Leg Circ ODSCC HTS 120 3 12 100 SCI HTS -0.07 Hot Leg Circ ODSCC HTS 121 3 29 57 SAI H02 0.04 - 95-05 DSI>1v Confirmed 122 3 25 28 SAI H01 -0.09 - Prevent - DSI <1v at FDB Note 1: 86-inch stabilizer installed SG-CDMP-20-23-NP March 2021 Revision 2 Page 71 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Table A3-4: Watts Bar U2R3 Tube Plug and Stabilization List for SG-4 Count SGID Row Col Ind Locn Inch1 Stabilizer(1) Reason 1 4 17 6 SAI H02 0.08 - 95-05, DSI>1 Confirmed 2 4 4 21 SAI H02 0.02 - 95-05, DSI>1 Confirmed 3 4 6 29 SAI H04 0 - 95-05, DSI>1 Confirmed 4 4 6 31 SAI H04 0.05 - 95-05, DSI>1 Confirmed 5 4 7 34 SAI H04 0.04 - 95-05, DSI>1 Confirmed 6 4 6 36 DSV H02 0 - 95-05 DSI>URL 7 4 19 40 SAI H02 0.14 - 95-05, DSI>1 Confirmed 8 4 6 41 SAI H02,H03,H04 0 - 95-05, DSI>1 Confirmed 9 4 11 43 SAI H02 0.14 - 95-05, DSI>1 Confirmed 10 4 7 46 SAI H04 0.13 - 95-05, DSI>1 Confirmed 11 4 6 50 SAI H02 0 - 95-05, DSI>1 Confirmed 12 4 16 55 SCI HTS -0.13 Hot Leg Circ ODSCC HTS 13 4 11 56 SCI HTS -0.1 Hot Leg Circ ODSCC HTS 14 4 21 57 SCI HTS -0.01 Hot Leg Circ ODSCC HTS 15 4 22 57 SCI HTS -0.07 Hot Leg circ ODSCC HTS 16 4 8 59 SAI H02, H04 0.11 - 95-05, DSI>1 Confirmed 17 4 5 62 SAI H03 0 - 95-05, DSI>1 Confirmed 18 4 18 66 SCI HTS -0.21 Hot Leg Circ ODSCC HTS 19 4 17 67 SCI HTS -0.03 Hot Leg Circ ODSCC HTS 20 4 21 67 SCI HTS -0.03 Hot Leg circ ODSCC HTS 21 4 12 68 SAI H03 -0.14 - 95-05, DSI>1 Confirmed 22 4 19 68 SCI HTS -0.1 Hot Leg Circ ODSCC HTS 23 4 20 68 SCI HTS -0.01 Hot Leg Circ ODSCC HTS 24 4 22 69 MAI HTS -0.11 - axial ODSCC at HTS 25 4 21 74 SCI HTS -0.19 Hot Leg circ ODSCC HTS 26 4 5 76 SCI HTS 0.07 Hot Leg circ ODSCC HTS 27 4 16 76 SAI H02 0.25 - 95-05, DSI>1 Confirmed 28 4 19 77 SCI HTS -0.1 Hot Leg circ ODSCC HTS 29 4 16 79 SCI HTS -0.03 Hot Leg circ ODSCC HTS 30 4 6 82 SCI HTS 0.04 Hot Leg circ ODSCC HTS 31 4 10 82 SCI HTS -0.15 Hot Leg circ ODSCC HTS 32 4 6 84 SCI HTS 0 Hot Leg circ ODSCC HTS SAI AV2 1.32 - Axial Ding Crack 33 4 49 84 SAI H02 -0.04 - 95-05, DSI>1 Confirmed 34 4 15 104 SCI HTS -0.06 Hot Leg circ ODSCC HTS 35 4 15 105 SCI HTS -0.06 Hot Leg circ ODSCC HTS 36 4 11 112 SAI H02 0.01 - 95-05, DSI>1 Confirmed Note 1: 86-inch stabilizer installed SG-CDMP-20-23-NP March 2021 Revision 2 Page 72 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Attachment 4 - Watts Bar U2R3 Circumferential ODSCC at HTS Sizing Summary Table A4-1. Watts Bar U2R3 Circumferential ODSCC at HTS Sizing Summary Indication Summary Resolution Sizing Depth Profiling Sizing

+POINT Maximum Segment Quick Maximum Segment Depth Tube 300kHz Depth, Arc, Screen Depth Depth, Arc, Profile Count SG Row Col Ind Locn Inch1 Vpp %TW Deg. PDA Profiled? %TW Deg. PDA 1 1 3 70 SCI HTS -0.04 0.09 79 55.4 7.2 Y 79 65 13.81 2 1 4 57 SCI HTS -0.05 0.09 44 32.3 2.3 - - -

3 1 4 65 SCI HTS -0.03 0.1 61 115.4 11.5 Y 44 114 9.54 4 1 30 77 SCI HTS -0.16 0.27 90 163.1 24.1 Y 86 172 35.42 5 1 41 39 SCI HTS -0.17 0.15 15 56.9 1.9 6 1 44 30 SCI HTS -0.02 0.19 90 67.7 10.0 Y 96 81 19.91 7 2 45 65 SCI HTS -0.06 0.11 50 84.6 6.9 - - -

8 3 5 96 SCI HTS -0.12 0.18 NQI 66.2 2.2 - - -

9 3 6 21 SCI HTS -0.02 0.28 9 116.9 3.8 - - -

10 3 9 70 SCI HTS -0.03 0.22 63 61.5 6.3 - - -

11 3 9 98 SCI HTS -0.11 0.19 45 86.2 6.4 - - -

12 3 10 78 SCI HTS -0.15 0.2 NQI 81.5 2.7 - - -

13 3 12 67 MCI HTS -0.08 0.17 53 83.1 7.2 - - -

14 3 12 100 SCI HTS -0.07 0.33 30 166.2 8.2 - - -

15 3 12 105 SCI HTS -0.11 0.16 36 90.8 5.4 - - -

16 3 13 88 SCI HTS -0.09 0.16 26 52.3 2.2 - - -

17 3 14 55 SCI HTS -0.15 0.25 NQI 109.2 3.6 - - -

18 3 14 57 SCI HTS -0.17 0.13 53 49.2 4.3 - - -

19 3 14 91 MCI HTS -0.05 0.21 31 123.1 6.3 - - -

20 3 14 98 SCI HTS -0.08 0.18 67 66.2 7.3 - - -

21 3 14 99 SCI HTS -0.1 0.29 73 87.7 10.5 Y 45 101 8.91 22 3 14 101 SCI HTS -0.05 0.29 48 116.9 9.2 - - -

23 3 15 82 SCI HTS -0.04 0.17 31 116 5.9 - - - -

SG-CDMP-20-23-NP March 2021 Revision 2 Page 73 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Table A4-1. Watts Bar U2R3 Circumferential ODSCC at HTS Sizing Summary Indication Summary Resolution Sizing Depth Profiling Sizing

+POINT Maximum Segment Quick Maximum Segment Depth Tube 300kHz Depth, Arc, Screen Depth Depth, Arc, Profile Count SG Row Col Ind Locn Inch1 Vpp %TW Deg. PDA Profiled? %TW Deg. PDA 24 3 16 71 SCI HTS -0.15 0.14 12 43.1 1.4 - - - -

25 3 17 44 SCI HTS -0.04 0.41 0 198.5 6.5 Y 20 194 11.3 26 3 19 57 SCI HTS -0.09 0.19 35 160 9.2 - - - -

27 3 21 56 SCI HTS -0.04 0.29 45 113.8 8.4 - - - -

28 3 22 62 SCI HTS -0.05 0.31 35 184.6 10.6 Y - - -

29 3 22 66 SCI HTS -0.1 0.62 39 186.2 11.9 Y 52 212 26.61 30 3 22 84 SCI HTS -0.11 0.11 22 72.3 2.6 - - - -

31 3 23 56 MCI HTS -0.06 0.27 27 197 8.7 Y 75 319 28.29 32 3 23 85 SCI HTS -0.04 0.14 68 166.2 18.5 Y 86 177 29.66 33 3 25 60 SCI HTS -0.23 0.32 36 135.4 8.0 - - - -

34 3 26 45 SCI HTS -0.1 0.28 18 95.4 3.1 - - - -

35 3 26 71 SCI HTS -0.09 0.2 21 90.8 3.1 - - - -

36 3 29 21 SCI HTS -0.1 0.19 NQI 118.5 3.9 - - - -

37 3 32 57 SCI HTS -0.05 0.15 70 83.1 9.5 - - - -

38 3 38 59 MCI HTS -0.04 0.15 78 144.6 18.5 Y 48 161 21.79 39 3 39 28 SCI HTS -0.05 0.11 14 80 2.6 - - - -

40 3 40 64 MCI HTS -0.05 0.27 33 150.8 8.2 - - - -

41 3 41 71 SCI HTS -0.1 0.15 39 60 3.8 - - - -

42 3 43 25 SCI HTS -0.08 0.26 52 67.7 5.8 - - - -

SCI HTS -0.05 0.16 51 73.8 6.2 Y 51.0 89 8.41 43 3 44 26A SCI HTS -0.05 0.26 52 100 8.5 Y 76 110 16.9 44 3 45 28 SCI HTS -0.08 0.22 55 76.9 6.9 - - - -

45 3 45 38 SCI HTS -0.03 0.13 34 143.1 8.0 - - - -

46 3 46 74 MCI HTS -0.14 0.18 50 84.6 6.9 - - - -

47 3 46 83 SCI HTS -0.05 0.17 16 55.4 1.8 - - - -

SG-CDMP-20-23-NP March 2021 Revision 2 Page 74 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Table A4-1. Watts Bar U2R3 Circumferential ODSCC at HTS Sizing Summary Indication Summary Resolution Sizing Depth Profiling Sizing

+POINT Maximum Segment Quick Maximum Segment Depth Tube 300kHz Depth, Arc, Screen Depth Depth, Arc, Profile Count SG Row Col Ind Locn Inch1 Vpp %TW Deg. PDA Profiled? %TW Deg. PDA 48 3 47 73 SCI HTS -0.07 0.18 28 100 4.6 - - - -

49 3 49 31 SCI HTS -0.04 0.26 NQI 146.2 4.8 - - - -

50 3 49 79 SCI HTS -0.04 0.17 NQI 61.5 2.0 - - - -

38A MCI HTS -0.05 0.21 44 116.9 8.4 Y 40.0 114 8.23 51 3 49 38B MCI HTS -0.06 0.18 81 60 8.0 Y 84 63 11.32 52 4 5 76 SCI HTS 0.07 0.17 21 163.1 5.6 - - - -

53 4 6 82 SCI HTS 0.04 0.24 21 166.2 5.7 - - - -

54 4 6 84 SCI HTS 0 0.2 32 232.3 12.2 Y 60 251 20.41 55 4 10 82 SCI HTS -0.15 0.19 35 58.5 3.4 - - - -

56 4 11 56 SCI HTS -0.1 0.17 27 95.4 4.7 - - - -

57 4 15 104 SCI HTS -0.06 0.24 26 144.6 6.2 - - - -

58 4 15 105 SCI HTS -0.06 0.2 11 107.7 3.5 - - - -

59 4 16 55 SCI HTS -0.13 0.25 21 110.8 3.8 - - - -

60 4 16 79 SCI HTS -0.03 0.26 42 95.4 6.6 - - - -

61 4 17 67 SCI HTS -0.71 0.21 39 133.8 8.6 - - - -

62 4 18 66 SCI HTS -0.21 0.27 50 190.8 15.6 Y 62 192 13.51 63 4 19 68 SCI HTS -0.1 0.24 58 67.7 6.4 - - - -

64 4 19 77 SCI HTS -0.1 0.24 24 56.9 2.2 - - - -

65 4 20 68 SCI HTS -0.01 0.3 26 196.9 8.4 Y 64 190 20.15 66 4 21 57 SCI HTS -0.01 0.36 43 180 12.7 Y 65 204 27.38 67 4 21 67 SCI HTS -0.03 0.21 28 136.9 6.3 - - - -

68 4 21 74 SCI HTS -0.19 0.18 39 67.7 4.3 - - - -

69 4 22 57 SCI HTS -0.34 0.41 28 116.9 5.4 Y 39 147 11.71 SG-CDMP-20-23-NP March 2021 Revision 2 Page 75 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Attachment 5 - Watts Bar U2R3 Possible Loose Part (PLP) Indications Table A5-1: Watts Bar U2R3 Possible Loose Part Indications (PLPs)

Visually Visually PSI U2R1 U2R2 U2R3 Inspected in Inspected Fluid Gap SG Row Col Volts Deg Ind Locn Inch1 PLP PLP PLP PLP 2019? in 2020? Velocity Resolution Comments 1 4 26 3.65 69 PLP H08 11.83 N Y Y Y No No [ ]a,c,e Leave in Service Low Flow Region 1 5 1 6.45 72 PLP H02 3.05 N N N Y No No [ ]a,c,e Leave in Service 1 5 2 4.82 73 PLP H02 3.4 N N N Y No No [ ]a,c,e Leave in Service 1 5 28 22.2 94 PLP HTS 0.2 N N Y N Yes No [ ] a,c,e Leave in Service Nothing Found 2018 1 5 42 15.52 47 PLP HTS 0.02 N Y Y N Yes No [ ] a,c,e Leave in Service Nothing Found 2017 No Object Observed Pre-1 6 1 11.33 71 PLP H01 0 Y Y Y N No No [ ]a,c,e Leave in Service Service No Object Observed Pre-1 6 1 9.35 73 PLP H01 7.02 Y Y Y N No No [ ]a,c,e Leave in Service Service No Object Observed Pre-1 6 1 0.11 147 PLP H02 15.05 Y Y Y N No No [ ]a,c,e Leave in Service Service No Object Observed Pre-1 6 1 2.86 72 PLP H02 15.14 Y Y N N No No [ ]a,c,e Leave in Service Service No Object Observed Pre-1 7 2 0.44 149 PLP H02 1.31 N N Y Y No No [ ]a,c,e Leave in Service Service 1 7 3 9.67 87 PLP H02 1.09 N N N Y No No [ ]a,c,e Leave in Service No Object Observed Pre-1 8 2 3.81 59 PLP H01 8.33 Y N NDF N No No [ ]a,c,e Leave in Service Service 1 8 3 23.93 80 PLP H02 0.7 N N Y Y No No [ ]a,c,e Leave in Service Low Flow Region 1 8 4 11.08 86 PLP H02 0.59 N Y Y Y No No [ ]a,c,e Leave in Service Low Flow Region Changed to NDD based on 1 8 41 3.99 86 PLP HTS 0.43 N N Y N No No [ ]a,c,e Leave in Service LAR 1 8 90 24.7 81 PLP C02 0.47 N N N Y No No [ ]a,c,e Leave in Service 1 8 90 22.87 120 PLP C02 0.6 N N N Y No No [ ]a,c,e Leave in Service 1 9 42 0.69 53 PLP H01 0.93 Y Y NDF N No No [ ]a,c,e Leave in Service Nothing Found 2017 1 9 43 21.76 85 PLP H01 0.71 N Y Y Y No No [ ]a,c,e Leave in Service Nothing Found 2017 1 10 42 28.3 86 PLP H01 2.09 Y Y Y Y No No [ ]a,c,e Leave in Service Nothing Found 2017 1 10 42 1.17 70 PLP H01 2.14 Y Y Y Y No No [ ]a,c,e Leave in Service Nothing Found 2017 1 10 43 27.36 88 PLP H01 0.53 N Y Y Y No No [ ]a,c,e Leave in Service Nothing Found 2017 1 10 43 22.45 85 PLP H01 2.14 N Y Y Y No No [ ]a,c,e Leave in Service Nothing Found 2017 1 10 58 12.88 82 PLP C01 0.87 N N N Y No No [ ]a,c,e Leave in Service No Object Observed Pre-1 11 2 0.24 151 PLP H01 11.36 Y Y Y N No No [ ]a,c,e Leave in Service Service SG-CDMP-20-23-NP March 2021 Revision 2 Page 76 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Table A5-1: Watts Bar U2R3 Possible Loose Part Indications (PLPs)

Visually Visually PSI U2R1 U2R2 U2R3 Inspected in Inspected Fluid Gap SG Row Col Volts Deg Ind Locn Inch1 PLP PLP PLP PLP 2019? in 2020? Velocity Resolution Comments No Object Observed Pre-1 11 2 7.31 64 PLP H01 11.43 Y Y N N No No [ ]a,c,e Leave in Service Service 1 12 53 11.67 74 PLP C02 0.93 N N Y N No No [ ] a,c,e Leave in Service Low Flow Region 1 12 53 17.02 74 PLP C02 0.4 N N Y Y No No [ ] a,c,e Leave in Service Low Flow Region No Object Observed Pre-1 15 81 1.47 52 PLP C01 3.01 Y Y Y Y No No [ ]a,c,e Leave in Service Service 1 15 81 13.12 79 PLP C01 3.21 N N N Y No No [ ] a,c,e Leave in Service Changed to NDD based on 1 18 36 11.07 72 PLP HTS 0.08 N N Y N No No [ ]a,c,e Leave in Service LAR 1 22 6 24.91 94 PLP C06 0.64 N N Y Y No No [ ]a,c,e Leave in Service Low Flow Region 1 24 9 2.4 119 PLP C04 0.91 N N N Y No No [ ] a,c,e Leave in Service 1 24 54 2.99 47 PLP HTS 1.07 N N N Y No Yes [ ] a,c,e Leave in Service 1 25 7 6.93 102 PLP C06 0.7 N N Y N No No [ ] a,c,e Leave in Service Low Flow Region 1 25 7 26.08 93 PLP C06 0.72 N N Y Y No No [ ] a,c,e Leave in Service Low Flow Region 1 25 101 14.58 85 PLP HTS 0.34 N Y NDF N No No [ ]a,c,e Leave in Service Object 1009 in 2017 1 26 15 26.33 91 PLP C01 0.52 N N Y Y No No [ ] a,c,e Leave in Service Low Flow Region 1 26 16 27.21 91 PLP C01 0.56 N N Y Y No No [ ] a,c,e Leave in Service Low Flow Region 1 26 16 15.84 92 PLP C01 1.6 N Y N N No No [ ] a,c,e Leave in Service Low Flow Region 1 26 16 19.31 80 PLP C01 2.04 N Y N N No No [ ] a,c,e Leave in Service Low Flow Region 1 26 16 1.07 62 PLP C01 2.05 N Y N N No No [ ] a,c,e Leave in Service Low Flow Region 1 26 18 17.43 91 PLP C06 0.29 N N N Y No No [ ] a,c,e Leave in Service No Object Observed Pre-1 26 83 26.71 96 PLP H01 0.59 N N Y Y No No [ ]a,c,e Leave in Service Service No Object Observed Pre-1 26 84 29.91 94 PLP H01 0.51 N N Y Y No No [ ]a,c,e Leave in Service Service 1 27 15 31.6 94 PLP C01 0.55 N N Y Y No No [ ] a,c,e Leave in Service Low Flow Region 1 27 16 30.37 90 PLP C01 0.56 N N Y Y No No [ ] a,c,e Leave in Service Low Flow Region 1 27 16 0.54 56 PLP C01 2.03 N Y N N No No [ ] a,c,e Leave in Service Low Flow Region 1 27 16 7.8 84 PLP C01 2.17 N Y N N No No [ ] a,c,e Leave in Service Low Flow Region 1 27 30 31 82 PLP C09 0.54 N N N Y No No [ ] a,c,e Leave in Service 1 27 84 27.65 95 PLP H01 0.78 N Y Y Y No No [ ] a,c,e Leave in Service Low Flow Region 1 27 85 28.87 92 PLP H01 0.76 N N Y Y No No [ ] a,c,e Leave in Service Low Flow Region SG-CDMP-20-23-NP March 2021 Revision 2 Page 77 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Table A5-1: Watts Bar U2R3 Possible Loose Part Indications (PLPs)

Visually Visually PSI U2R1 U2R2 U2R3 Inspected in Inspected Fluid Gap SG Row Col Volts Deg Ind Locn Inch1 PLP PLP PLP PLP 2019? in 2020? Velocity Resolution Comments 1 28 30 6.99 89 PLP C09 0.73 N N N Y No No [ ]a,c,e Leave in Service 1 29 30 25.82 89 PLP C09 0.73 N N N Y No No [ ]a,c,e Leave in Service 1 31 70 11.22 68 PLP HTS 0.16 N N N Y No Yes [ ]a,c,e Leave in Service 1 32 31 8.43 79 PLP HTS 0.16 N N N Y No Yes [ ]a,c,e Leave in Service 1 33 13 8.69 79 PLP HTS 0.06 Y Y Y Y Yes Yes [ ]a,c,e Leave in Service Nothing Found 2017 1 33 31 10.41 76 PLP HTS 0.6 N N Y Y Yes Yes [ ]a,c,e Leave in Service Nothing Found 2018 1 33 32 17.66 74 PLP HTS 0.83 N N Y Y Yes Yes [ ]a,c,e Leave in Service Nothing Found 2018 1 34 28 7.24 259 PLP HTS 0.08 N N Y N Yes No [ ]a,c,e Leave in Service Nothing Found 2018 1 34 31 8.58 74 PLP HTS 1.97 N N N Y No Yes [ ]a,c,e Leave in Service 1 34 32 13.05 69 PLP HTS 1.74 N N N Y No Yes [ ]a,c,e Leave in Service 1 35 14 26.05 86 PLP C09 0.55 N N N Y No No [ ]a,c,e Leave in Service 1 35 15 27.14 88 PLP C09 0.53 N N N Y No No [ ]a,c,e Leave in Service 1 35 15 24.47 93 PLP C09 0.58 N N Y Y No No [ ]a,c,e Leave in Service Low Flow Region 1 35 15 21.19 91 PLP C09 0.59 N N Y N No No [ ]a,c,e Leave in Service Low Flow Region 1 35 28 16.74 80 PLP HTS 0.22 N N Y N Yes No [ ]a,c,e Leave in Service Nothing Found 2018 1 35 29 9.47 68 PLP HTS 0.38 N N N Y No Yes [ ]a,c,e Leave in Service 1 36 15 28.5 85 PLP C09 0.55 N N N Y No No [ ]a,c,e Leave in Service 1 36 27 25.41 84 PLP H01 1.37 N Y Y Y No No [ ]a,c,e Leave in Service Low Flow Region 1 36 27 0.66 65 PLP H01 2.27 N N N Y No No [ ]a,c,e Leave in Service 1 36 27 25.66 85 PLP H01 2.49 N Y Y Y No No [ ]a,c,e Leave in Service Low Flow Region 1 36 28 17.7 83 PLP HTS 0.2 N N Y N Yes No [ ]a,c,e Leave in Service Nothing Found 2018 1 37 27 34.18 84 PLP H01 1.34 N Y Y Y No No [ ]a,c,e Leave in Service Low Flow Region 1 37 27 1.21 69 PLP H01 1.58 N N N Y No No [ ]a,c,e Leave in Service 1 37 27 27.52 83 PLP H01 2.43 N Y Y Y No No [ ]a,c,e Leave in Service Low Flow Region 1 37 27 0.6 64 PLP H01 2.89 N N N Y No No [ ]a,c,e Leave in Service 1 37 53 7.02 68 PLP C02 0.61 N N N Y No No [ ]a,c,e Leave in Service 1 39 44 11.38 256 PLP HTS 0.12 N N Y N Yes No [ ]a,c,e Leave in Service Nothing Found 2018 SG-CDMP-20-23-NP March 2021 Revision 2 Page 78 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Table A5-1: Watts Bar U2R3 Possible Loose Part Indications (PLPs)

Visually Visually PSI U2R1 U2R2 U2R3 Inspected in Inspected Fluid Gap SG Row Col Volts Deg Ind Locn Inch1 PLP PLP PLP PLP 2019? in 2020? Velocity Resolution Comments 1 39 45 12.49 77 PLP HTS 0.08 N N Y N Yes No [ ] a,c,e Leave in Service Nothing Found 2018 1 47 37 7.36 81 PLP C02 0.63 N N N Y No No [ ] a,c,e Leave in Service 1 48 64 12.7 68 PLP C02 0.47 N N Y Y No No [ ]a,c,e Leave in Service Low Flow Region 1 48 64 12.01 129 PLP C02 0.62 N N N Y No No [ ]a,c,e Leave in Service 1 49 47 16.01 76 PLP C03 0.7 N N N Y No No [ ]a,c,e Leave in Service 2 3 71 0.52 63 PLP C02 2.72 N NDF N No No [ ]a,c,e Leave in Service Low Flow Region Object 2008 Weld Slag in 2 7 2 12.57 87 PLP HTS 0.39 Y Y NDF N No No [ ]a,c,e Plug, Stabilize 2017 Object 2008 touching tube based on visual inspection 2 7 3 HTS N N NDF N No No [ ] a,c,e Plug, Stabilize 2 7 113 27.34 91 PLP C08 0.59 N Y Y Y No No [ ] a,c,e Leave in Service Low Flow Region Object 2008 Weld Slag in 2 8 2 19.97 91 PLP HTS 0.32 N Y NDF N No No [ ]a,c,e Plug, Stabilize 2017 Object 2008 Weld Slag in 2 8 3 27.91 87 PLP HTS 0.03 N Y NDF N No No [ ]a,c,e Plug, Stabilize 2017 2 8 113 24.01 83 PLP C08 0.7 N Y Y Y No No [ ]a,c,e Leave in Service Low Flow Region 2 8 113 7.55 113 PLP C08 0.85 N Y N N No No [ ]a,c,e Leave in Service Low Flow Region 2 11 5 0.52 66 PLP C02 -1.2 N N Y Y No No [ ] a,c,e Leave in Service Low Flow Region 2 11 5 9.14 108 PLP C02 -1.07 N N Y Y No No [ ] a,c,e Leave in Service Low Flow Region 2 11 9 5.83 122 PLP C06 -1.27 N N Y N No No [ ] a,c,e Leave in Service Low Flow Region 2 13 20 16.38 78 PLP C02 0.36 N Y Y Y No No [ ] a,c,e Leave in Service Low Flow Region 2 13 20 15.93 115 PLP C02 0.53 N Y N Y No No [ ] a,c,e Leave in Service Low Flow Region Low Flow Region, Deposit-2 23 56 3.5 104 PLP CTS 0.3 N Y NDF N No No [ ]a,c,e Leave in Service Like Low Flow Region, Deposit-2 23 56 12.98 73 PLP CTS 0.43 N Y NDF N No No [ ]a,c,e Leave in Service Like 2 29 19 8.36 84 PLP C01 0.65 N N Y N No No [ ]a,c,e Leave in Service Low Flow Region 2 32 103 14.53 114 PLP C05 0.1 N N Y N No No [ ]a,c,e Leave in Service Low Flow Region 2 37 50 5 121 PLP C03 -0.06 N N N Y No No [ ]a,c,e Leave in Service Object 2015 in 2017 Hard 2 42 33 13.72 83 PLP HTS 0.27 N Y NDF N No No [ ]a,c,e Leave in Service Sludge Object 2015 in 2017 Hard 2 42 34 19.67 85 PLP HTS 0.31 N Y NDF N No No [ ]a,c,e Leave in Service Sludge SG-CDMP-20-23-NP March 2021 Revision 2 Page 79 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Table A5-1: Watts Bar U2R3 Possible Loose Part Indications (PLPs)

Visually Visually PSI U2R1 U2R2 U2R3 Inspected in Inspected Fluid Gap SG Row Col Volts Deg Ind Locn Inch1 PLP PLP PLP PLP 2019? in 2020? Velocity Resolution Comments 2 46 27 12.61 77 PLP H02 0.6 N N Y Y No No [ ] a,c,e Leave in Service Low Flow Region 2 46 27 10.62 73 PLP H02 2 N N Y Y No No [ ] a,c,e Leave in Service Low Flow Region 2 46 27 9.42 69 PLP H02 2.18 N N N Y No No [ ]a,c,e Leave in Service 2 46 28 16.35 73 PLP H02 0.87 N N N Y No No [ ]a,c,e Leave in Service 2 46 28 16.6 76 PLP H02 1.01 N Y Y Y No No [ ]a,c,e Leave in Service Low Flow Region 2 46 28 1.1 65 PLP H02 2.24 N Y Y Y No No [ ]a,c,e Leave in Service Low Flow Region 2 46 28 17.1 78 PLP H02 2.34 N Y Y Y No No [ ]a,c,e Leave in Service Low Flow Region Object 2009 in 2017 Sludge 2 46 58 9.49 76 PLP HTS 0.37 N Y NDF N No No [ ]a,c,e Leave in Service Rock 2 47 28 0.57 66 PLP H02 2.29 N Y Y Y No No [ ]a,c,e Leave in Service Low Flow Region 2 47 28 12.56 77 PLP H02 2.32 N Y Y N No No [ ]a,c,e Leave in Service Low Flow Region No Object Observed Pre-2 47 87 18.81 80 PLP HTS -0.04 Y Y Y Y Yes Yes [ ]a,c,e Leave in Service Service 3 4 42 13.4 74 PLP C02 0.45 N N N Y No No [ ] a,c,e Leave in Service 3 4 56 14.22 67 PLP C04 0.49 N N N Y No No [ ]a,c,e Leave in Service 3 6 45 12.16 70 PLP C02 0.41 N N Y Y No No [ ]a,c,e Leave in Service Low Flow Region 3 7 44 1.81 75 PLP C02 0.48 N N Y Y No No [ ]a,c,e Leave in Service Low Flow Region No Object Observed Pre-I 3

1 -3 8

- - - - - --+--

4 6.46 4- - - -12.14

+----+-

74 85---+-

PLP PLP C01 C02 _

- - - + -_

0.58 0.68---+----+--_----+----------_______ ____ ________.

Y N

Y N

Y N

Y Y

No No No No

[

[

]a,c,e

] a,c,e Leave in Service Leave in Service Service No Object Observed Pre-3 9 2 0.32 75 PLP H01 11.49 Y Y Y Y No No [ ]a,c,e Leave in Service Service I 3 12 41 1.5 66 PLP C02 1 - - - - - - - - - - + - - - - - - + - - - - + - - - - + - - - - + -_ _

3 19 83 13.65 70 PLP HTS 0.4 0.1

---+----+--_----+----------_______ ------------<

N N

N N

Y Y

Y Y

No No No Yes

[

[

]a,c,e

]a,c,e Leave in Service Leave in Service Low Flow Region Present and unchanged in history 3 34 19 1.6 98 PLP CTS 2.84 N N Y N No No [ ] a,c,e Leave in Service Low Flow Region 3 35 96 12.56 68 PLP C01 1.68 N N N Y No No [ ] a,c,e Leave in Service 3 35 96 4.8 98 PLP C01 1.8 N N N Y No No [ ] a,c,e Leave in Service 3 35 97 2.95 67 PLP C01 1.38 N N N Y No No [ ] a,c,e Leave in Service 3 35 97 0.17 58 PLP C01 1.54 N N N Y No No [ ] a,c,e Leave in Service 3 35 97 11.79 68 PLP C01 1.69 N N N Y No No [ ] a,c,e Leave in Service 3 49 66 17.26 79 PLP C06 -1.04 N N N Y No No [ ] a,c,e Leave in Service SG-CDMP-20-23-NP March 2021 Revision 2 Page 80 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Table A5-1: Watts Bar U2R3 Possible Loose Part Indications (PLPs)

Visually Visually PSI U2R1 U2R2 U2R3 Inspected in Inspected Fluid Gap SG Row Col Volts Deg Ind Locn Inch1 PLP PLP PLP PLP 2019? in 2020? Velocity Resolution Comments 4 1 28 19.28 80 PLP HTS 0.11 N Y NDF N No No [ ] a,c,e Leave in Service Nothing Found 2017 4 1 29 11.39 81 PLP HTS 0.19 N Y NDF N No No [ ] a,c,e Leave in Service Nothing Found 2017 4 2 34 16.62 89 PLP HTS 0.14 N Y NDF N No No [ ]a,c,e Leave in Service Nothing Found 2017 4 2 36 18.11 80 PLP HTS 0.05 N Y NDF N No No [ ]a,c,e Leave in Service Nothing Found 2017 4 3 113 18.26 82 PLP C02 0.35 N N N Y No No [ ]a,c,e Leave in Service 4 5 95 23.5 72 PLP HTS 0.33 N N N Y No Yes [ ]a,c,e Leave in Service 4 6 35 3.11 235 PLP C09 1.63 N Y NDF N No No [ ]a,c,e Leave in Service NDF +Point 2017 4 6 50 12.06 116 PLP C04 1.08 N N Y N No No [ ] a,c,e Leave in Service Low Flow Region 4 7 2 18.47 76 PLP HTS 0.42 N Y NDF N No No [ ] a,c,e Leave in Service Nothing Found 2017 4 7 29 15.63 69 PLP HTS 0.41 N N Y N Yes No [ ] a,c,e Leave in Service Nothing Found 2018 4 7 35 4.11 68 PLP C09 1.22 N Y NDF N No No [ ] a,c,e Leave in Service NDF +POINT 2017 4 8 61 8.69 116 PLP C04 1.06 N N Y N No No [ ] a,c,e Leave in Service Low Flow Region 4 9 40 10.34 67 PLP HTS 0.17 N N N Y No Yes [ ] a,c,e Leave in Service 4 12 90 3.11 67 PLP C01 1.13 N N Y N No No [ ] a,c,e Leave in Service Low Flow Region 4 12 91 4.6 78 PLP C01 1.16 N N N Y No No [ ] a,c,e Leave in Service 4 16 31 14.07 80 PLP C02 0.48 N N N Y No No [ ] a,c,e Leave in Service 4 16 31 1.28 77 PLP C02 0.69 N N N Y No No [ ] a,c,e Leave in Service 4 17 35 26.8 69 PLP HTS -0.12 N N Y Y Yes Yes [ ] a,c,e Leave in Service Nothing Found 2018 4 17 35 23.93 71 PLP HTS 0.16 N N N N Yes No [ ]a,c,e Leave in Service 4 20 54 1.96 300 PLP C06 -1.12 N N Y N No No [ ]a,c,e Leave in Service Low Flow Region 4 22 34 4.54 111 PLP CTS 0.68 N N Y N Yes No [ ]a,c,e Leave in Service Nothing Found 2018 4 23 45 15.68 93 PLP C05 0.88 N N Y N No No [ ]a,c,e Leave in Service Low Flow Region 4 24 42 12.64 70 PLP C01 0.63 N N Y N No No [ ] a,c,e Leave in Service Low Flow Region 4 24 42 16.5 80 PLP C02 0.75 N N Y N No No [ ] a,c,e Leave in Service Low Flow Region 4 24 46 15.59 74 PLP C02 0.84 N N Y N No No [ ] a,c,e Leave in Service Low Flow Region 4 25 7 25.07 81 PLP HTS 0.15 Y Y Y Y Yes Yes [ ] a,c,e Leave in Service Nothing Found 2018 4 27 88 8.76 69 PLP HTS 0.33 N N N Y No Yes [ ] a,c,e Leave in Service SG-CDMP-20-23-NP March 2021 Revision 2 Page 81 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Table A5-1: Watts Bar U2R3 Possible Loose Part Indications (PLPs)

Visually Visually PSI U2R1 U2R2 U2R3 Inspected in Inspected Fluid Gap SG Row Col Volts Deg Ind Locn Inch1 PLP PLP PLP PLP 2019? in 2020? Velocity Resolution Comments 4 29 49 11.28 73 PLP C02 0.87 N N Y N No No [ ] a,c,e Leave in Service Low Flow Region 4 31 37 18.4 83 PLP HTS 0.6 N N Y N Yes No [ ] a,c,e Leave in Service Object 4008 in 2018 4 31 38 18.55 82 PLP HTS 0.69 N N Y N Yes No [ ]a,c,e Leave in Service Object 4008 in 2018 4 35 18 23.07 107 PLP C01 0.06 N N N Y No No [ ]a,c,e Leave in Service Object 4005 in 2017 Sludge 4 35 20 9.34 83 PLP HTS 0.31 N Y Y Y Yes Yes [ ]a,c,e Leave in Service Rock 4 35 39 12.27 86 PLP C01 0.63 N N Y N No No [ ]a,c,e Leave in Service Low Flow Region 4 36 17 19.31 93 PLP C03 0.66 N N N Y No No [ ] a,c,e Leave in Service Object 4005 in 2017 Sludge 4 36 20 11.51 88 PLP HTS 0.46 N Y Y Y Yes Yes [ ]a,c,e Leave in Service Rock 4 36 58 14.23 73 PLP HTS 0.65 N N N Y No Yes [ ]a,c,e Leave in Service 4 37 23 0.46 61 PLP CTS 2.61 N Y Y Y Yes Yes [ ] a,c,e Leave in Service Nothing Found 2018 4 37 23 1.62 90 PLP CTS 2.76 N N N Y No Yes [ ] a,c,e Leave in Service Nothing Found 2018 4 37 49 15.8 82 PLP HTS 0 N Y NDF N No No [ ] a,c,e Leave in Service Sludge in 2017 4 38 23 13.79 71 PLP CTS 2.57 N N Y Y Yes Yes [ ]a,c,e Leave in Service Nothing Found 2018 4 38 23 9.01 91 PLP CTS 2.73 N N N Y No Yes [ ]a,c,e Leave in Service Nothing Found 2018 4 38 61 1.41 93 PLP CTS 0.18 N N N Y No Yes [ ]a,c,e Leave in Service 4 40 49 1.43 80 PLP C05 0.58 N N N Y No No [ ]a,c,e Leave in Service 4 42 63 7.08 68 PLP HTS 0.46 N N N Y No Yes [ ]a,c,e Leave in Service 4 42 66 0.44 66 PLP H01 18.03 Y Y NDF N No No [ ] a,c,e Leave in Service NDF +POINT 2017 4 44 23 2.61 149 PLP C05 0.92 N Y NDF N No No [ ] a,c,e Leave in Service NDF +POINT 2017 4 44 42 11.65 77 PLP C01 0.73 N N Y N No No [ ] a,c,e Leave in Service Low Flow Region 4 44 56 14.61 70 PLP HTS 0.19 N Y NDF N No No [ ] a,c,e Leave in Service Sludge in 2017 4 44 70 14.28 83 PLP HTS 0.21 N N N Y No Yes [ ] a,c,e Leave in Service 4 45 25 10.34 66 PLP HTS 0.05 Y Y NDF N No No [ ] a,c,e Leave in Service Nothing Found 2017 4 46 36 2.93 269 PLP C05 7.81 N N Y N No No [ ] a,c,e Leave in Service NDF +POINT 2018 4 46 42 7.27 69 PLP HTS 0.57 Y Y NDF N No No [ ] a,c,e Leave in Service Nothing Found 2017 4 47 37 13.38 84 PLP C02 0.73 N N Y N No No [ ] a,c,e Leave in Service Low Flow Region 4 47 41 17.28 92 PLP C02 0.7 N N Y N No No [ ] a,c,e Leave in Service Low Flow Region SG-CDMP-20-23-NP March 2021 Revision 2 Page 82 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Table A5-1: Watts Bar U2R3 Possible Loose Part Indications (PLPs)

Visually Visually PSI U2R1 U2R2 U2R3 Inspected in Inspected Fluid Gap SG Row Col Volts Deg Ind Locn Inch1 PLP PLP PLP PLP 2019? in 2020? Velocity Resolution Comments 4 48 37 9.97 78 PLP C05 0.94 N N Y N No No [ ] a,c,e Leave in Service NDF +POINT 2018 4 48 66 14.14 80 PLP HTS 0.31 N Y NDF N No No [ ] a,c,e Leave in Service Sludge in 2017 4 48 68 2.3 95 PLP C02 0.03 N N N Y No No [ ]a,c,e Leave in Service 4 49 67 16.88 83 PLP HTS 1.08 N Y NDF N No No [ ]a,c,e Leave in Service Sludge in 2017 SG-CDMP-20-23-NP March 2021 Revision 2 Page 83 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Watts Bar Unit 2 Model D3 U2R3 PLP Indications Tubesheet Map o Base Tubes

  • SG 1 4 SG 2 SG3 :t: SG4 so 0000000001 000000 00 000000000, 00000 000 000000000 POOOO 0 000000000, 000000000( 0000000001 000000 J( O 000000000 t,OOO0OO ao 000000 01 000000000( 000000000 000000000 000000000 pooooooa ou o 000000000< 0000 000 0000000004 00000000 000000000 ,000000000 45

-:,000000 000000000, 000000000 000000000, 000000000 000000000 POOOOuOooo, ,oo 000000001 000000000* 000000000 000000000* 000000000 000000000 1000000000, 1c)Ov oouoooooo 000000000 000000000 000000000 00)1(000000 000000000 pOOOOOOCJOO i,t,oo 000000000 oooooooooc 000000000 000000000 000000000 000000000 000000000 oooou 40 - -- - .

00 000000000 000000000< 000000000 000000000 000000000 000000000 bOOOOOOOOO 0000000 000 00)1(000000 000000000 000000000 000000000 *11(0 0000000 000000000 POOOOOOOOO 00000000 0000 00)1(000 ~ 0 000000000 000000000 ~00 000000 000000000 000000000 pooooooooo 000000000 0 11 00 ~000000 .-:i o 000000000 000000000 0000000 ::s:o 000000000 000000000 000000000 000000000 35 0000000 POOOOOOOOO ~ 000000, 000000000 0000000001 000000000 000000000 P000000000 000000000, 00 0000000 000000000 . . , ,000000, 000000000 000000000 000000000 000000000 P000000000 000000000 000 00000000 000000000 00000000 000000000 000000000 000000000 000000000 000000000 000000000 000 000000000 000000000 000000000! 000000000 000000000 000000000 000000000 000000000 000000000 0000 30 - --- - ---- --- -- -- - - - - --- -- -- - - - --

000000000 1000000000 ~ 000000001 000,,00000, 000000000, 000000000 000000000 0000000000 ,000000000, 00000 0 000000000 !000000000 ~ 00000000, 000000000, 000000000, 000000000 000000000 POOOOOOOOO 000000000* 000000 00 0000 000 000000000 K> 00000000 000000000< 000000000 000000000 ,000000000 000 00 11 0 *000000000 0000000 00 O~OO!f>O O 000000000 0000000001 oo~ooo~~o, 000000000 000000000 000000000 bOO OOOOO 000000000 0000000 Do* 000000000 1000oocooo 00000001 000000000( 000 00000, 000000000 000000000 000 00000 0000000001 00000000 0000 000000000 !000000000 0000000001 000000000, 000000000, 000000000 000000000 POOOOOOOOO 000000000, 000000000 OOO 000000000 000000000 000000000, 000000000( 000000000 000000000 000000000 000000000 000000000 000000000 00000 000000000 1000000000 oooc,00000, 000000000( 000000000, 000000000 000000000 b000000000 0000000001 000000000, 20 Oi)OOO OOCIOC,0000 b000000000* 000,:,00000, 0,:,0000000, oc,0000000 OOCI000000 00000000,:, 1ov o00000 000000000, OOOOOt>OOO<

000000 000000000 000000000< 0000000(.)0C 000000000< 000000000 000000000 000000000 000000000 000000000 000000000t0 000000 OOOOt,0000 00C.,IJ0Q000< 0000 11(0000< OC,0000000< 1 oooaoooo 000000000 (.,OOOUOOOll OOOOOOOc!O OOOOO<JOOO 000000000,0 000000 000000000 000000000

  • 00000000 000000000( 000000000 000000000 000000000, 000000000 000000000 000000000<0 15 -

0000000 000000000 r, 000000000 000000000, 000000000 000000000 000000000 000000000 000000000 000000000 000000000* 00 0000000 OOOOOOOOOJ~000000000 oooooooooc 000000000 000000000 000000000 000000000 000000000 000000000 000000000 00 00000000 000000000 000000000 000000000 00000000 00 ~ 00000 000000000 000000000 000000000 )1(00000000, 000000000 C*OO oo':~ oooo 000000000 000000000 ~ooooo~~~c 000000000 000000000 000000000 000000000 000000000 000000000 ~0~~000~0( 000 10 -. - - - - - " - - - ., -- - - --

0000000 000000000 000000000 000000000: ~00 000000 000000000, 000000000 000000000 P000000000 *000000000 000000000 000 O OOOOO 000000000 000000000 oooooooooc 000000000 000000000 000000000 000000000 000000000, 000000000 000000000 OO il

. . 000000 1000000000 ooeiaooooo oooooooooc ooo i.o oooo ()00000000 000000000 IC*OOOOOOOCt pooooooooo 000000000 000000000 ooa 000000000 0000(*0000 1000000000 000000000 0(*00 00001 00000000*) OOC*OOO*)OO 00000000(* bOOOOOOOOO 00000*)0001 000000000 0000 5

000000000 000000000 00000 oa 000000000 o ,.,000000 00000 000 000000000 0000:)0000 ooooooaoo 000000000 000000000 0000 000000000 OOOO<>OOCJO OOOOOCJuOOt 000000000, 000000000 000000000 000000000 *000000000 1000000000 ,000000000, 000000000 00 11 oo*JOOOOOO ooooooeio, ,000000000 0000000001 000cooooo 000000000, 000000000 0000')0000 ,000000000 000000000, 0')0000000 0000 000.,00000 oc,00.00000 1000000000, 000000000, 000000000 000000000 000000000 000000000 1000000000 000000000, 000000000 0000 0 0 0 10 20 30 40 50 60 70 80 90 100 110 COLUMN Figure A5-1. Watts Bar U2R3 Tube Possible Loose Part Indications in All SGs Note: All PLP indications are shown regardless of whether they are located in the hot leg, cold leg, tube upper bundle, etc.

SG-CDMP-20-23-NP March 2021 Revision 2 Page 84 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Attachment 6 - Watts Bar U2R3 Tube Proximity Indications Table A6-1: Watts Bar U2R3 Tube Proximity Indications (PRX), All SGs SG Row Col Volts Deg Ind Locn Inch1 Inch2 1 11 104 2.35 126 PRX H08 18.33 25.9 1 25 16 1.02 107 PRX AV3 7.02 2.54 1 26 16 1.01 104 PRX AV3 4.62 6.59 1 26 16 0.41 307 PRX H08 20.97 12 1 27 16 0.55 109 PRX H08 16.6 7.81 1 33 83 0.76 0 PRX AV3 20.14 5.84 1 38 82 2.28 88 PRX AV3 10.57 22.15 1 39 82 0.65 0 PRX AV4 9.16 27.88 1 42 86 0.68 113 PRX AV3 9.98 26.11 1 43 86 0.58 0 PRX AV4 31.8 3.77 1 44 27 0.61 110 PRX AV4 1.93 29.53 1 44 82 0.61 123 PRX AV3 16.46 30.17 1 44 89 0.65 0 PRX AV3 16.46 28.85 1 45 27 0.96 99 PRX AV4 1.82 27.56 1 45 82 0.7 0 PRX AV2 22.44 24.52 1 46 82 0.46 0 PRX AV2 21.64 27.54 1 46 82 0.55 0 PRX AV4 3.97 27.55 1 46 82 0.8 0 PRX C13 23.25 40.42 1 47 80 0.7 135 PRX AV3 1.6 31.3 1 48 80 0.9 270 PRX AV3 6.89 12.64 2 13 95 0.5 174 PRX C13 11.55 38.07 2 30 59 1.35 296 PRX AV3 10.55 22.8 2 31 59 0.92 274 PRX AV3 10.32 40.91 2 33 52 1.16 283 PRX AV3 4 46 2 34 92 1.03 103 PRX H08 27.03 5.39 2 35 82 0.52 0 PRX AV2 13.85 20.65 2 35 84 0.51 0 PRX AV3 14.88 23 2 36 84 1.05 0 PRX AV3 6.28 18.85 2 36 84 0.57 0 PRX H08 12 19.35 2 36 91 0.76 90 PRX AV3 2.29 6.31 2 36 91 0.91 115 PRX H08 4.25 4.72 2 36 92 0.7 100 PRX H08 5.32 19.1 2 36 93 0.65 100 PRX H08 12.66 19.21 2 37 63 0.65 88 PRX AV3 5.58 19.25 2 37 77 1 128 PRX H08 6.49 28.49 2 37 82 0.66 0 PRX H08 5.5 9.05 2 37 87 0.72 312 PRX H08 24.32 20.9 2 37 88 1.06 108 PRX H08 8.44 9.03 2 37 91 0.71 95 PRX H08 9.76 28.21 SG-CDMP-20-23-NP March 2021 Revision 2 Page 85 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Table A6-1: Watts Bar U2R3 Tube Proximity Indications (PRX), All SGs SG Row Col Volts Deg Ind Locn Inch1 Inch2 2 37 92 0.54 115 PRX H08 1.73 1.15 2 37 93 0.46 86 PRX H08 9.45 18.5 2 37 98 0.67 114 PRX H08 9.89 12.74 2 38 98 1.07 115 PRX AV2 14.22 5.75 2 39 64 0.68 125 PRX H08 5.04 46.96 2 39 66 0.65 0 PRX AV3 6.23 15.35 2 39 74 0.56 0 PRX H08 21.96 2.1 2 39 75 0.81 123 PRX AV1 2.06 11.34 2 39 84 0.56 0 PRX H08 22 21.55 2 39 90 0.88 113 PRX H08 6.22 15.01 2 40 56 0.31 137 PRX AV2 10.62 -

2 40 56 0.4 104 PRX H08 26.33 -

2 40 64 0.87 125 PRX H08 4.95 36.12 2 40 66 0.84 0 PRX AV3 6.65 16.32 2 40 70 0.55 0 PRX H08 20.36 17.56 2 40 75 0.58 127 PRX H08 17.72 23.96 2 40 81 0.85 108 PRX AV3 8.77 26.34 2 40 83 1.16 113 PRX AV3 14.56 25.85 2 40 90 0.94 106 PRX AV1 11.63 10.2 2 40 90 0.58 99 PRX AV3 4.84 15.39 2 40 94 0.78 94 PRX AV2 20.49 10.85 2 40 95 0.94 98 PRX AV3 1.02 25.91 2 41 66 1.05 0 PRX AV1 22.05 14.88 2 41 69 0.88 127 PRX AV2 7.26 14.41 2 41 71 1 117 PRX AV3 10.43 23.55 2 41 73 0.58 123 PRX AV3 7.39 16.63 2 41 81 1.13 110 PRX AV4 0.72 27.27 2 41 82 0.37 0 PRX H08 21.9 17 2 41 86 0.85 0 PRX AV1 15.88 21.65 2 41 87 0.52 307 PRX AV1 16.09 31.95 2 41 90 1.1 102 PRX AV3 18.05 13.37 2 41 92 1.02 92 PRX AV2 7.75 15.28 2 41 95 1.07 98 PRX AV2 17.78 16.03 2 42 64 0.43 125 PRX AV1 2.27 24.27 2 42 66 0.7 0 PRX AV2 5.8 18.25 2 42 70 0.86 0 PRX AV1 7.1 24.05 2 42 91 0.65 106 PRX H08 11.34 13.54 2 42 92 1.07 79 PRX H08 11.35 17.52 2 43 77 0.71 92 PRX AV2 5.84 16.46 2 43 86 0.46 0 PRX H08 7.34 23.55 2 43 87 0.68 131 PRX AV1 28.01 68.07 SG-CDMP-20-23-NP March 2021 Revision 2 Page 86 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Table A6-1: Watts Bar U2R3 Tube Proximity Indications (PRX), All SGs SG Row Col Volts Deg Ind Locn Inch1 Inch2 2 43 88 0.72 123 PRX H08 11.68 18.44 2 43 91 0.73 120 PRX H08 15.64 7.7 2 44 88 0.76 111 PRX AV3 4.37 14.1 2 45 63 1.19 126 PRX H08 23.89 81.59 2 45 65 1.32 121 PRX H08 10.33 13.62 2 45 66 0.86 0 PRX H08 17.5 18.85 2 45 68 0.53 0 PRX AV1 18.84 17.34 2 45 68 0.82 0 PRX AV4 2.85 26.32 2 45 72 0.54 0 PRX H08 17.89 24.85 2 45 74 0.49 0 PRX H08 28.12 17.55 2 45 78 0.7 0 PRX AV1 19.47 14.34 2 45 80 0.4 0 PRX AV2 8.49 14.35 2 45 82 0.41 0 PRX AV3 2.5 3.32 2 45 83 0.82 123 PRX AV3 1.97 26.72 2 45 84 0.38 0 PRX H08 16.6 27.55 2 45 85 0.53 317 PRX AV3 9.36 -

2 45 86 0.68 0 PRX H08 12.05 3.35 2 45 87 0.64 121 PRX AV3 24.28 20.48 2 45 87 0.57 115 PRX H08 17.38 3.8 2 45 88 0.73 107 PRX AV3 7.98 10.84 2 46 56 0.71 121 PRX H08 19.72 2 46 73 0.47 88 PRX AV2 2.54 21.15 2 46 81 0.51 112 PRX AV3 12.09 26.91 2 46 83 1.16 119 PRX AV3 3.81 27.74 2 46 85 0.68 115 PRX AV2 21.69 -

2 46 87 0.62 134 PRX AV1 12.97 70.1 2 47 63 0.78 105 PRX H08 4.24 28.76 2 47 67 0.89 288 PRX AV1 12.22 17.3 2 47 71 0.61 103 PRX AV4 4.43 17.3 2 47 72 0.61 0 PRX AV1 15.5 26.55 2 47 74 0.32 0 PRX AV2 23.79 6.34 2 47 75 0.6 104 PRX AV2 -0.31 40 2 47 76 0.64 0 PRX AV3 16.54 17.88 2 47 77 1.03 116 PRX AV1 27.39 24.07 2 47 78 0.7 0 PRX AV3 24.65 46.87 2 47 80 0.73 0 PRX AV3 18.23 25.35 2 47 81 1.1 117 PRX AV3 2.12 29.51 2 47 83 1.23 121 PRX AV4 1.95 31.53 2 47 86 0.57 0 PRX AV3 22.09 29.65 2 48 62 0.81 315 PRX H08 1.01 59.48 2 48 63 0.49 83 PRX H08 11.52 16.77 SG-CDMP-20-23-NP March 2021 Revision 2 Page 87 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Table A6-1: Watts Bar U2R3 Tube Proximity Indications (PRX), All SGs SG Row Col Volts Deg Ind Locn Inch1 Inch2 2 48 64 0.79 137 PRX H08 20.65 64.08 2 48 66 0.7 0 PRX AV1 18.95 -

2 48 68 0.49 0 PRX AV1 5.05 22.66 2 48 72 0.52 0 PRX AV1 17.09 -

2 48 75 0.36 0 PRX AV1 -1.05 -

2 48 77 0.36 0 PRX AV1 16.46 19 2 48 81 0.3 0 PRX AV1 12.85 22.55 3 41 94 0.8 110 PRX AV3 1.4 22.69 3 42 94 0.63 91 PRX AV3 2.4 22.51 3 44 86 0.49 102 PRX H08 7.01 25.28 3 45 82 0.34 78 PRX H08 5.09 14.49 3 45 84 0.7 114 PRX AV1 20.86 -1.61 3 45 86 0.84 60 PRX H08 18.25 31.57 3 45 87 1.14 96 PRX H08 10.89 21.2 3 46 82 0.23 130 PRX H08 3.92 31 3 46 84 1.58 278 PRX AV1 11.34 65.14 3 46 86 0.64 62 PRX H08 6.33 29.96 3 47 84 0.84 99 PRX AV1 13.75 16.93 3 47 86 1.37 289 PRX AV2 9.12 13.62 4 34 97 0.68 87 PRX AV3 12.43 20.46 4 35 97 0.71 95 PRX AV3 14.97 20.55 4 36 97 0.67 87 PRX AV3 0.57 5.59 4 37 97 0.76 90 PRX AV3 0.43 13.66 4 37 98 0.69 88 PRX H08 13.21 4.3 4 38 75 0.26 118 PRX H08 24.65 16.1 4 38 77 0.63 107 PRX H08 10.48 18.61 4 38 81 1.12 154 PRX H08 2.43 7.47 4 38 98 0.95 89 PRX H08 20.53 -1.61 4 39 75 0.8 53 PRX AV1 8.75 -

4 39 77 0.57 106 PRX H08 3.34 20.6 4 39 81 0.38 115 PRX H08 11.61 16.5 4 39 93 0.45 91 PRX H08 5.04 24.43 4 40 73 1.59 87 PRX H08 11.81 -0.6 4 40 95 0.74 281 PRX H08 23.69 2.46 4 41 73 0.83 55 PRX H08 7.87 21.2 4 41 76 0.5 101 PRX AV3 8.48 16.15 4 41 77 0.15 115 PRX AV3 3.92 -

4 41 81 0.46 101 PRX AV3 6.58 18.33 4 41 85 0.7 67 PRX AV3 10.75 28.79 4 41 93 0.32 108 PRX AV2 18.37 79.47 4 41 95 0.66 76 PRX H08 16.15 21.67 SG-CDMP-20-23-NP March 2021 Revision 2 Page 88 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Table A6-1: Watts Bar U2R3 Tube Proximity Indications (PRX), All SGs SG Row Col Volts Deg Ind Locn Inch1 Inch2 4 42 76 1.01 82 PRX AV3 12.98 19.01 4 42 77 0.06 111 PRX AV4 -1.27 -

4 42 81 0.66 91 PRX AV3 20.71 17.48 4 42 82 0.84 102 PRX AV3 18.03 24.47 4 42 85 0.76 84 PRX AV3 8.97 22.86 4 42 93 0.82 93 PRX AV3 1.56 17.48 4 45 77 0.22 102 PRX H08 8.66 -

4 46 73 2.02 279 PRX AV1 25.76 -1.98 4 46 77 0.47 98 PRX AV1 -1.27 -

4 46 87 0.56 86 PRX AV1 15.82 11.69 4 47 60 0.38 0 PRX AV3 5.23 24.08 4 47 73 1.28 95 PRX AV2 1.36 28.17 4 47 77 0.27 95 PRX AV3 17.1 -

4 47 80 0.36 107 PRX AV2 21.22 19.94 4 47 81 0.4 99 PRX AV2 15.15 25.65 4 47 82 1.92 85 PRX AV2 20.56 25.03 4 47 83 0.33 112 PRX AV2 26.08 21.64 4 47 84 0.79 92 PRX AV2 18.74 27.09 4 47 85 1.03 93 PRX AV2 23.4 21 4 47 86 0.65 90 PRX AV3 2.45 27.54 4 47 87 0.61 88 PRX AV2 2.92 -1.13 4 48 77 1.23 79 PRX AV4 1.06 -

4 48 80 0.47 109 PRX AV3 27.81 21.95 4 48 81 0.31 108 PRX AV3 15.1 19.42 4 48 82 0.37 116 PRX AV3 16.59 16.11 4 48 84 0.73 84 PRX AV2 21.24 19.35 4 48 85 0.55 271 PRX AV2 21.82 30.46 4 48 86 1.2 82 PRX AV2 10.34 17.8 SG-CDMP-20-23-NP March 2021 Revision 2 Page 89 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 Watts Bar Unit 2 Model 03 U2R3 PRX Indications Tubesheet Map o Base Tubes A SG2

  • SG3 XSG4 50 000000000~000000000! 000000000 000000000 000000000 0000 o 000000000,000000000, 000000000 ou.t.oAoa o oa ooa o* ooi _..o._.

oo 00~000000, 000000000, 000000000, ooAoooa oo ~au iAll*~*~*Lat*lLttLot.-:IQlllll(P oo~o ::o:?oooo~::<~oo~ ~o~ oooooa ~oo ooooooo~ ~oa oo~~ o~ d ~oo 45 0000.-0 0 000000000,000000000 000000000 00 0 00000 0 0 0 0 0 0000 0 , a.o oo oa oo 00000000 000000000(000000000 000000000 000000000 ooooooa oo ooooouao a oo 000000000 000000000( 000000000, 000000000 oooa 0a o00 00000)0(00 JIOIC 00 )1( oooiuu pooooooooo 000000000(000000000 000000000 oooooa ooa * ~! oo,aoo u oo)l(lloo ao~

40 oo 00~000000 oooaooooo<;,0~00000.;, ~00000 000 oooi:oAo_;o ooollo*oo{ iiOioooc~ aoc*oooo 000 000000000 000000000<000000000 000000000 000000000 OOOO)l(OWOO W OOOOOOO 0000000.

0000 000000000 000000000,000000000, 000000000 ooa oooooo ooooooa oo, oa oooou o aaao0oq o 00000 000000000 000000000( 000000000, 000000000 000000000 000000000 oooa oooooiaaa ooo~oo 35 - - -

0000000 000000000 000000000<000000000, 000000000 000000000 000000000 oOOOooooo~oa oooox ooi oo 00000000 000000000 000000000(000000000 0 &0000000 000000000 000000000 00 000000 000000000 000 00000000 000000000 000000000(000000000 000000000 000000000 000000000 000000000 000000000 000 000000000 000000000 000000000,000000000, 00000000 &* 000000000 000000000 000000000 000000000, 0000 30 000000000 000000000 000000000,000000000 00000000 0 000000000 000000000, 000000000 000000000 00000 0 000000000 000000000 000000000<000000000 000000000 000000000 000000000 000000000 000000000, 000000 00 OOOOO OOO 000000000 000000000(000000000 000000000 000000000 000000000 000000000 000000000 0000000

~ 25

~o ~000 ~ 000 ~000000000 oo~~oooooc~~oo0000~1 ~~~ooo~oo 000000000 ~~000000~ .~~oo~~~~o 000 000000000 000000000 0000000(000000000 000000000 000000000 000000000 00

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00000 000000000 00000000 a:: 0000 000000000 000000000 000000000,000000000 000000000 000000000 000000000 000000000 000000000 ooooooouo 0000 000000000 000000000 OOOOOOOOOtOOOOOOOOO 000000000 000000000 000000000 000000000 000000000 000000000 00000 000000000 oocoooooo 000000000(000000000 000000000 000000000 000000000 000000000 000000000 000000000 20 00000 000000000 000000000 000000000<000000000 000000000 000000000 000000000 000000000* 000000000 000000000 ooQOoo~o~ooooooo 00~000000 0000000~0< 0000000001000000000, oo~ooooco 00000~000 oooooocoo~oooooooooi ooaoooooo, o 000000 000000000 000000000 000000000< 000000000 000000000* 000000000 000000000 000000000 000000000, 000000000 0 000000 000000000 oooooocoo ooooooooocooooooooo 000000000 oooocoooo 000000000 ~oocooooo 000000000 000000000 a 15 0000000 000000000 000000000 000000000(000000000 000000000 000000000 000000000 000000000 000000000 000000000 00 0000000 000000000 000000000 000000000,000000000 000000000 000000000 000000000 000000000 ooooa oooo 000000000 oo 00000000 0~0000000 000000000 0000000~0( OOOOOCOOOI 000000000 000000000 00000~~00 000000000~0000000001 000000000 OOC 10 00000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000000000, 000 00000 000 00000000 000000000 000000000 000000000<000000000< 000000000 000000000 000000000, 000000000 1000000000 000000000 000 00000000 000000000 000000000 000000000( 000000000 000000000 000000000 000000000 000000000 000000000 000000000 000 00000000 000000000 000000000 000000000< 000000000 000000000 000000000 000000000< 000000000 000000000 000000000 000 000000000 000000000 000000000 000000000( 000000000 000000000 000000000 000000000( 000000000 000000000 000000000 0000 5

000000000~000000000 000000000 000000000(0000000001000000000 000000000 000000000( 000000000 ~000000000 000000000 0000 000000000 000000000 000000000 000000000< 000000000, 000000000 000000000 000000000, 000000000 1000000000 000000000 0000 000000000 000000000 000000000 000000000< 000000000, 000000000 000000000 000000000< 000000000 1000000000 000000000 0000 000000000 000000000 000000000 000000000<000000000< 000000000 000000000 000000000< 0000000001000000000 000000000 0000 0 0 0 10 20 30 40 so 60 70 80 90 100 110 COLUMN Figure A6-1. Watts Bar U2R3 Tube Proximity Indications in All SGs SG-CDMP-20-23-NP March 2021 Revision 2 Page 90 of 90

      • This record was final approved on 3/12/2021 4:51:17 PM. (This statement was added by the PRIME system upon its validation)

Enclosure 3 Westinghouse Electric Company LLC Application for Withholding Proprietary Information from Public Disclosure (Affidavit CAW-21-5162)

CNL-21-040

Westinghouse Non-Proprietary Class 3 CAW-21-5162 Page 1 of 3 COMMONWEALTH OF PENNSYLVANIA:

COUNTY OF BUTLER:

(1) I, Zachary S. Harper, have been specifically delegated and authorized to apply for withholding and execute this Affidavit on behalf of Westinghouse Electric Company LLC (Westinghouse).

(2) I am requesting the proprietary portions of SG-CDMP-20-23-P, Revision 2, Watts Bar U2R3 Steam Generator Condition Monitoring and Final Operational Assessment, be withheld from public disclosure under 10 CFR 2.390.

(3) I have personal knowledge of the criteria and procedures utilized by Westinghouse in designating information as a trade secret, privileged, or as confidential commercial or financial information.

(4) Pursuant to 10 CFR 2.390, the following is furnished for consideration by the Commission in determining whether the information sought to be withheld from public disclosure should be withheld.

(i) The information sought to be withheld from public disclosure is owned and has been held in confidence by Westinghouse and is not customarily disclosed to the public.

(ii) The information sought to be withheld is being transmitted to the Commission in confidence and, to Westinghouses knowledge, is not available in public sources.

(iii) Westinghouse notes that a showing of substantial harm is no longer an applicable criterion for analyzing whether a document should be withheld from public disclosure. Nevertheless, public disclosure of this proprietary information is likely to cause substantial harm to the competitive position of Westinghouse because it would enhance the ability of competitors to provide similar technical evaluation justifications and licensing defense services for commercial power reactors without

Westinghouse Non-Proprietary Class 3 CAW-21-5162 Page 2 of 3 commensurate expenses. Also, public disclosure of the information would enable others to use the information to meet NRC requirements for licensing documentation without purchasing the right to use the information.

(5) Westinghouse has policies in place to identify proprietary information. Under that system, information is held in confidence if it falls in one or more of several types, the release of which might result in the loss of an existing or potential competitive advantage, as follows:

(a) The information reveals the distinguishing aspects of a process (or component, structure, tool, method, etc.) where prevention of its use by any of Westinghouse's competitors without license from Westinghouse constitutes a competitive economic advantage over other companies.

(b) It consists of supporting data, including test data, relative to a process (or component, structure, tool, method, etc.), the application of which data secures a competitive economic advantage (e.g., by optimization or improved marketability).

(c) Its use by a competitor would reduce his expenditure of resources or improve his competitive position in the design, manufacture, shipment, installation, assurance of quality, or licensing a similar product.

(d) It reveals cost or price information, production capacities, budget levels, or commercial strategies of Westinghouse, its customers or suppliers.

(e) It reveals aspects of past, present, or future Westinghouse or customer funded development plans and programs of potential commercial value to Westinghouse.

(f) It contains patentable ideas, for which patent protection may be desirable.

Westinghouse Non-Proprietary Class 3 CAW-21-5162 Page 3 of 3

( 6) The attached documents are bracketed and marked to indicate the bases for withholding. The justification for withholding is indicated in both versions by means oflower-case letters (a) through (f) located as a superscript immediately following the brackets enclosing each item of information being identified as proprietary or in the margin opposite such information. These lower-case letters refer to the types of information Westinghouse customarily holds in confidence identified in Sections (5)(a) through (f) of this Affidavit.

I declare that the averments of fact set forth in this Affidavit are true and correct to the best of my knowledge, information, and belief.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on: tl/4,g/,R,aJZ {

~gcr Licensing Engineering

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