CP-202200419, (CPNPP) - Unit 1 Refueling Outage 22 (1RF22) Steam Generator 180 Day Report

(CPNPP) - Unit 1 Refueling Outage 22 (1RF22) Steam Generator 180 Day Report

ML22308A178
Person / Time
Site:	Comanche Peak
Issue date:	11/03/2022
From:	Hicks J Luminant, Vistra Operating Co. (VistraOpCo)
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
CP-202200419, TXX-22087
Download: ML22308A178 (1)

Text

CP-202200419 TXX-22087 November 3, 2022 U. S. Nuclear Regulatory Commission Ref 10CFR50.55a ATTN: Document Control Desk TS 5.6.9 Washington, DC 20555-0001

Subject:

Comanche Peak Nuclear Power Plant (CPNPP)

Docket No. 50-445 Unit 1 Refueling Outage 22 (1RF22) Steam Generator 180 Day Report

Dear Sir or Madam:

Vistra Operations Company LLC (Vistra OpCo) hereby submits the Comanche Peak Nuclear Power Plant (CPNPP) Unit 1 steam generator tube inspection report for 1RF22 as required by Technical Specification 5.6.9.

This communication contains no new commitments regarding CPNPP Unit 1.

Should you have any questions, please contact Jim Barnette at (254) 897-5866 or James.barnette@luminant.com.

Sincerely, Jack C. Hicks

Attachment:

180 Day Steam Generator Tube Inspection Report - Comanche Peak Unit 1 Cycle 22 c (email) -

Scott Morris, Region IV [Scott.Morris@nrc.gov]

Dennis Galvin, NRR [Dennis.Galvin@nrc.gov]

John Ellegood, Senior Resident Inspector, CPNPP [John.Ellegood@nrc.gov]

Neil Day, Resident Inspector, CPNPP [Neil.Day@nrc.gov]

Jack C. Hicks Manager, Regulatory Affairs Comanche Peak Nuclear Power Plant (Vistra Operations Company LLC)

P.O. Box 1002 6322 North FM 56 Glen Rose, TX 76043 T

254.897.6725 Jack C Hicks

180 Day Steam Generator Tube Inspection Report - Comanche Peak Unit 1 Cycle 22

1. DESIGN AND OPERATING PARAMETERS Steam Generator (SG) Design and Operating Parameters SG Model / Tube Material / # SGs per unit Delta 76/ Alloy 690TT / 4

1. of tubes per SG / Nominal Tube Dia. / tube thickness 5,532/ 0.750 in / 0.043 in (except tubes in Rows 1 and 2, which have a nominal thickness of 0.044 inch)

Support Plate Style / Material Trefoil Broached Hole / Stainless Steel Last Inspection Date October 2017 (1RF19)

EFPM since the last inspection 50.28 Total cumulative SG EFPY 14.039 Mode 4 initial entry May 8, 2022 Observed P/S Leak Rate since the last inspection and how it trended with time No leakage observed Nominal indicated value of Thot during Cycle 22 at full power SG1-620 Degrees F SG2-623 Degrees F SG3-619 Degrees F SG4-624 Degrees F Tube sub-populations with increased degradation susceptibility The periphery tubes, including periphery along the divider plate are more likely to be affected by foreign object intrusion and wear Deviations from SGMP guidelines since the last inspection None SG Schematic See next page Attachment to TXX-22087 Page 1 of 9

Attachment to TXX-22087 Page 2 of 9

2. SCOPE OF INSPECTIONS PERFORMED ON EACH SG The 1RF22 inspection scope was implemented as-planned, with no scope expansion required.

The inspection program, as required by the EPRI Pressurized Water Reactor (PWR) SG Examination Guidelines and the EPRI SG Integrity Assessment Guidelines, addressed the existing degradation mechanisms observed in CPNPP Unit 1 in prior inspections as well as those regarded as potential degradation mechanisms. The inspection scope included the items listed below (for all SGs unless otherwise noted):

Primary Side 1.

100% Full Length Bobbin (straight legs only in Rows 1 through 3).

2.

100% +Point Rows 1-3 U-Bends.

3.

100% +Point Hot Leg TTS +/- 3 inches.

4.

100% +Point Dents/Dings 5 volts.

5.

100% +Point probe inspection of periphery three-tube deep in the Cold Leg +/- 3 inches TTS, including periphery along divider plate.

6.

100% +Point of all legacy loose parts, with box-in.

7.

100% +Point of Special interest:

a.

Newly reported PLPs by bobbin b.

100% of PRX indications reported by bobbin c.

Deposit (DEP) signals, as selected by Data Management or Engineering d.

Bobbin I-code indications e.

Newly reported signals at Tube Support Plates (TSP) f.

Data quality 8.

Hot Leg and Cold Leg primary channel head visual inspection per NSAL 12-1.

9.

Visual of all Hot Leg and Cold Leg plugs in all SGs.

10. Scale Profiling in SG1.

Secondary Side Inspection Scope The 1RF22 inspection scope was implemented as-planned. The inspection scope included the items listed below (for all SGs unless otherwise noted):

1.

Top of Tube Sheet (TTS) Foreign Object Search and Retrieval (FOSAR) / PLP Verification.

2.

TTS Visual in-Bundle Inspection every 20 columns.

3.

Upper Tube Bundle Visual Inspection in SG 1 (TSPs J and H).

3. THE NONDESTRUCTIVE EXAMINATION TECHNIQUES UTILIZED FOR TUBES WITH INCREASED DEGRADATION SUSCEPTIBILITY The periphery tubes, including periphery along the divider plate are more likely to be affected by foreign object intrusion and wear. Inspection for this area included +Point probe inspection and TTS visual inspection via FOSAR.

Attachment to TXX-22087 Page 3 of 9

4. THE NONDESTRUCTIVE EXAMINATION TECHNIQUES UTILIZED FOR EACH DEGRADATION MECHANISM FOUND Degradation Mechanism Detection Probe Type Detection Technique ETSS Sizing Probe Type Sizing Technique ETSS TSP Wear Bobbin I96043.1, Rev. 2

+Point 96910.1, Rev. 11 FO Wear Bobbin 27091.2, Rev. 2

+Point 21998.1, Rev. 4

5. LOCATION, ORIENTATION, MEASURED SIZE, AND VOLTAGE RESPONSES There were no indications of TSP or Foreign Object (FO) Wear with depth 20% TW. There were 43 indications of TSP wear and one (1) indication of FO wear with depths 20% TW. The TSP wear 20% TW is broken down by SG as: 7 in SG1, 6 in SG2, 13 in SG3, and 17 in SG4.

The single FO wear indication was in SG 3, R40C30 at 09C-0.64-inch, with an NDE depth of 9%TW. This is a historical FO wear indication, first detected at 1RF19, which shows no change in flaw morphology. Analysis of the +Point low frequency data at 1RF19 and 1RF22 shows that no foreign object remains at this location.

6. CONDITION MONITORING ASSESSMENT AND RESULTS, MARGIN TO THE TUBE INTEGRITY PERFORMANCE CRITERIA, AND COMPARISON WITH THE MARGIN PREDICTED TO EXIST AT THE INSPECTION BY THE PREVIOUS FORWARD-LOOKING TUBE INTEGRITY ASSESSMENT The EPRI PWR SG Examination Guidelines require that the existing degradation mechanisms identified in the DA be subject to appropriate inspection programs to comply with the plant SG Technical Specifications. The existing degradation mechanism in the CPNPP Unit 1 SGs for 1RF22 is TSP wear. Note that while an indication of FOW was identified at 1RF19, and the wear scar remains in service, further observation of this mechanism is dependent upon material ingress.

Therefore, this mechanism is treated as a potential degradation mechanism. For purposes of condition monitoring, it is included in the below table. The condition monitoring results for 1RF22 are presented in the table for all detected degradation mechanisms.

CPNPP 1RF22 Condition Monitoring Summary for Limiting Flaw Mechanism 1RF22 Limiting Flaw CM Limit SG Row Col IND Loc Depth

(%TW)

Length (in)

TSP Wear 4

103 87 WAR 07C 12 0.47 48.5% TW, 1.0-inch flaw FO Wear 3

40 30 VOL 09C 9

0.19 64% TW, 0.19-inch flaw 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 Attachment to TXX-22087 Page 4 of 9

accident induced leakage performance criteria (AILPC) at steam line break differential pressure.

Therefore, for all tube wear, the SG structural and leakage performance criteria are satisfied for condition monitoring.

SG Integrity Assessment Guidelines require condition monitoring results from the current inspection be compared to the OA from the previous inspection. This comparison identifies whether the underlying assumptions, input parameters, or methodology for performing OAs are conservative or require alteration prior to performing the next OA. Failure to meet CM requirements means that the projections of the prior OA were not conservative and that necessary corrective actions are to be identified. Even when CM requirements are met, this comparative review may identify adjustments to the OA inputs or assumptions.

For wear mechanisms, a comparison of the previous OA to the 1RF22 inspection results is presented in the table below.

Comparison of Previous Wear OA Projections to 1RF22 Results Mechanism 1RF19 Projection

(% TW) 1RF22 Limiting Flaw (% TW)

Anti-Vibration Bar (AVB) Wear - new 5.0 none TSP Wear - detected at 1RF19 35.5 12 TSP Wear - undetected at 1RF16 50.4 12 FO Wear 57.0 9

Based on the inspection data and the condition monitoring assessment, no tubes exhibited degradation exceeding the condition monitoring limits set forth in the 1RF22 DA. No tubes required in situ pressure or leak testing to demonstrate structural and leakage integrity. Therefore, the SG performance criteria for structural and leakage integrity were satisfied for all degradation mechanisms for the preceding CPNPP Unit 1 SG operating interval.

7. TUBES PLUGGED OR REPAIRED DURING THE INSPECTION OUTAGE.

No tubes were required to be plugged as a result of the 1RF22 inspections.

8. THE REPAIR METHODS UTILIZED, AND THE NUMBER OF TUBES REPAIRED BY EACH REPAIR METHOD N/A Attachment to TXX-22087 Page 5 of 9

9. ANALYSIS

SUMMARY

OF THE TUBE INTEGRITY CONDITIONS PREDICTED TO EXIST AT THE NEXT SCHEDULED INSPECTION The Operational Assessment for tube wear mechanisms was performed using conservative deterministic methods and growth rates to project EOC flaw depths for all existing and potential degradation mechanisms. For detected wear, this includes burst relation, material property and NDE measurement uncertainties. For Undetected wear, this includes burst relation and material property uncertainties. It was concluded that the projected EOC depth of the largest detected and assumed undetected flaw will remain below the calculated structural limits with sufficient margin at 1RF27. The OA calculations are summarized in the table below. For volumetric flaws ligament tearing is coincident to burst. Therefore, since structural integrity against tube burst at 3PNO was demonstrated, leakage integrity is expected to be maintained to at least 1RF27 as well.

The FO wear indication has experienced no growth since its initial reporting. No foreign objects remain within the vicinity of the affected tube. Therefore, there is no mechanism to produce further flaw progression during future operations.

A total of 36 foreign objects remained in secondary side of the SGs following 1RF22. All of these objects were small parts and, demonstrated by bounding calculations through tube wear projections, will not adversely affect tube integrity until at least 1RF27. None of the 36 foreign objects known to be remaining in the SGs are associated with FO wear.

The CM and OA for the CPNPP Unit 1 SGs at the 1RF22 outage follows the requirements of the SG Integrity Assessment Guidelines and complies with requirements of NEI-97-06. It has been shown that all existing and potential degradation mechanisms will maintain structural and leakage integrity until the next planned inspection at 1RF27.

Summary of 1RF22 OA Results Mechanism 1RF27 Projection Structural Limit AVB Wear - undetected 43.5% TW 61.5% TW, 0.55-inch TSP Wear - detected 54.2% TW 57.0% TW, 1.125-inch TSP Wear - undetected 39.3% TW 57.0% TW, 1.125-inch Foreign Object Wear - existing flaw 9% TW (no change predicted) 62.5% TW, 0.5-inch Attachment to TXX-22087 Page 6 of 9

10. NUMBER AND PERCENTAGE OF TUBES PLUGGED OR REPAIRED TO DATE, AND THE EFFECTIVE PLUGGING PERCENTAGE IN EACH SG The tube plugging summary for CPNPP Unit 1 is presented below.

SG

1. Tubes 1RF22 # Plugged Total # Plugged

% Plugging 1

5,532 0

0 0.00 2

5,532 0

0 0.00 3

5,532 0

1 0.02 4

5,532 0

1 0.02 Total 22,128 0

2 0.01

11. SG SECONDARY-SIDE INSPECTION RESULTS Foreign object search and retrieval (FOSAR) inspections were performed at 1RF22. FOSAR and deposit inspections of the annulus/peripheral bundle, tubelane, and pre-defined in-bundle columns in all SGs were performed. Upper tube bundle visual inspection (TSP J and H) were performed in SG1 in pre-defined columns. TSPs J, H, and the underside and flow holes of K were viewed during the upper bundle inspection. All were found to be in acceptable condition. Deposit loading on the support plate horizontal surfaces and the broached lands varied within the bundle, with more deposits generally built-up closer to the center of the bundle and on the higher supports. Overall, deposit loading appeared to be less than that observed in 1RF19.

A total of 49 objects were found during FOSAR and 13 were retrieved. For the objects remaining in the SG secondary side following CPNPP 1RF22, a foreign object evaluation has been performed. This assessment concludes that all loose parts remaining after 1RF22 are acceptable for an operating period of greater than 8 EFPY. Therefore, continued SG operation with the foreign objects known to be present in the secondary side will not adversely affect the SG tube integrity for at least 5-cycles or until the next schedule inspection at 1RF27. A summary of the FOSAR is provided in below tables.

Attachment to TXX-22087 Page 7 of 9

CPNPP 1RF22 Foreign Objects SG No.

FO No.

Retrieval Status Foreign Object Desc.

Is Metallic Leg Beg Row End Row Beg Col End Col Length (In.)

Width (In.)

Height (In.)

SG1 1001 Will Not Retrieve SHIM TRUE Cold Leg 92 94 96 97 0.08 0.08 0.01 SG1 1002 Will Not Retrieve Sludge FALSE Cold Leg 96 98 39 40 0.125 0.125 0.125 SG1 1003 Will Not Retrieve SCALE OR FALSE Hot Leg 39 39 56 57 0.15 0.14 0.02 SG1 1004 Will Not Retrieve Wire TRUE Hot Leg 40 41 57 58 0.5 SG1 1005 Will Not Retrieve SHIM TRUE Hot Leg 44 44 58 59 0.4 0.25 0.07 SG1 1006 Will Not Retrieve Wire TRUE Hot Leg 44 44 63 64 0.375 SG1 1007 Will Not Retrieve Wire TRUE Hot Leg 43 43 63 64 0.5 SG1 1008 Will Not Retrieve Scale TRUE Hot Leg 44 44 64 65 0.5 0.1 0.1 SG2 2001 Retrieved SHIM TRUE Hot Leg 104 106 51 52 0.375 0.15 0.01 SG2 2002 Retrieved SHIM TRUE Hot Leg 105 107 58 59 0.0312 0.375 0.25 SG2 2003 Retrieved plastic FALSE Hot Leg 101 102 59 60 0.14 0.14 0.14 SG2 2004 Retrieved SHIM TRUE Hot Leg 103 105 66 67 0.6 0.25 0.01 SG2 2005 Will Not Retrieve SHIM TRUE Hot Leg 46 47 30 31 0.2 0.1 0.01 SG2 2006 Will Not Retrieve SHIM TRUE Hot Leg 47 49 51 52 0.2 0.142 0.01 SG2 2007 Will Not Retrieve SHIM TRUE Hot Leg 50 52 51 52 0.625 0.15 0.01 SG2 2008 Retrieved Machine TRUE Hot Leg 37 39 58 59 0.625 0.15 0.0312 SG2 2009 Attempted but not Scale TRUE Hot Leg 38 40 59 60 0.5 0.0312 0.0312 SG2 2010 Will Not Retrieve SHIM TRUE Hot Leg 40 41 60 61 0.2 0.15 0.01 SG2 2011 Retrieved Gasket TRUE Hot Leg 80 82 60 61 0.75 0.0312 0.0312 SG2 2012 Non-Relevant Sludge FALSE Hot Leg 94 96 60 61 0.1875 0.1875 0.1875 SG2 2013 Will Not Retrieve SHIM TRUE Hot Leg 38 40 70 71 0.75 0.28 0.15 SG2 2014 Will Not Retrieve SHIM TRUE Hot Leg 37 39 69 70 0.6 0.25 0.15 SG2 2015 Retrieved SHIMI FALSE Hot Leg 93 94 90 91 0.25 0.2 0.2 SG2 2016 Will Not Retrieve Sludge FALSE Hot Leg 25 27 90 91 0.15 0.15 0.1 SG2 2017 Will Not Retrieve SHIM TRUE Hot Leg 93 95 58 59 0.12 0.08 0.01 SG2 2018 Will Not Retrieve SHIM TRUE Hot Leg 88 90 58 59 0.14 0.12 0.01 SG2 2019 Retrieved SHIM TRUE Hot Leg 83 85 58 59 0.375 0.14 0.01 SG2 2020 Will Not Retrieve SHIM TRUE Hot Leg 71 73 58 59 0.14 0.25 0.01 SG2 2021 Will Not Retrieve SHIM TRUE Hot Leg 65 67 58 59 0.14 0.25 0.01 SG2 2022 Retrieved SHIM TRUE Hot Leg 69 71 59 60 0.25 0.3 0.01 SG2 2023 Retrieved SHIM TRUE Hot Leg 75 79 59 60 0.5 0.2 0.01 SG2 2024 Retrieved SHIM TRUE Hot Leg 85 87 59 60 0.25 0.1875 0.01 SG2 2025 Will Not Retrieve Sludge FALSE Hot Leg 69 71 76 77 0.625 0.25 0.25 SG2 2026 Will Not Retrieve FILM TRUE Hot Leg 60 60 66 67 0.375 0.16 0.005 SG3 3001 Will Not Retrieve Wire TRUE Hot Leg 45 45 61 62 0.5 SG3 3002 Will Not Retrieve Wire TRUE Hot Leg 44 44 60 61 0.5 SG3 3003 Will Not Retrieve Wire TRUE Hot Leg 43 43 62 63 0.5 SG3 3004 Will Not Retrieve SHIM TRUE Hot Leg 38 40 70 71 0.5 0.14 0.01 SG3 3005 Will Not Retrieve Machine TRUE Hot Leg 35 37 71 72 0.14 SG3 3006 Will Not Retrieve SHIM TRUE Hot Leg 37 39 71 72 0.25 0.25 0.01 SG3 3007 Will Not Retrieve METAL TRUE Hot Leg 50 52 71 72 0.43 0.28 0.14 SG3 3008 Non-Relevant Sludge FALSE Cold Leg 29 31 50 51 0.15 0.15 0.1 SG3 3009 Retrieved SHIM TRUE Cold Leg 89 91 50 51 0.45 0.25 0.01 SG3 3010 Retrieved SHIM TRUE Cold Leg 106 107 63 64 0.3 0.15 0.1 SG3 3011 Will Not Retrieve Slag TRUE Hot Leg 63 64 55 56 0.3 0.28 0.03 SG3 3012 Will Not Retrieve Graphite TRUE Hot Leg 53 53 65 65 0.1 0.0625 0.005 SG3 3013 Will Not Retrieve Sludge FALSE Hot Leg 34 35 80 81 0.2 0.2 0.04 SG4 4001 Will Not Retrieve Scale FALSE Hot Leg 36 38 56 57 0.12 0.05 0.05 SG4 4002 Non-Relevant Scale FALSE Hot Leg 46 47 76 77 0.5 0.2 0.1 Attachment to TXX-22087 Page 8 of 9

12. THE SCOPE, METHOD, AND RESULTS OF SECONDARY-SIDE CLEANING PERFORMED IN EACH SG TTS sludge lancing with post-cleanliness inspection was performed in all SGs. The deposit removal amounts at 1RF22 were 2.75 lbs., 4.25 lbs., 5.25 lbs., and 4.75 lbs. in SGs 1, 2, 3, and 4, respectively.

The deposit removal amounts after the last sludge lancing at 1RF16 (no sludge lancing was performed in 1RF19) were 3 lbs., 4 lbs., 3.5 lbs., and 3 lbs. in SGs 1, 2, 3, and 4, respectively.

13. THE RESULTS OF PRIMARY SIDE COMPONENT VISUAL INSPECTIONS PERFORMED IN EACH SG The channel heads in all four SGs were inspected per Westinghouse Nuclear Safety Advisory Letter NSAL-12-1, Revision 1. No anomalies or signs of degradation were found.

A 100% visual inspection of tube plugs has been performed from the primary side during 1RF22. No anomalous conditions, such as a degraded tube plug or surrounding boron deposits, have been reported during performance of these visual inspections.

Attachment to TXX-22087 Page 9 of 9