ML23291A081

2023 Steam Generator Tube Inspection Report

ML23291A081
Person / Time
Site:	Ginna
Issue date:	10/18/2023
From:	Blankenship J Constellation Energy Generation
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
Download: ML23291A081 (1)

Text

Constellation October 18, 2023 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001

Subject:

R.E. Ginna Nuclear Power Plant Renewed Facility Operating License No. DPR-18 NRC Docket No. 50-244 2023 Steam Generator Tube Inspection Report James D. Blankenship Site Vice President R E. Ginna Nuclear Power Plant 1503 Lake Rd Ontario. NY 14519 315-791-5205 Office tames blankensh1p 1a constellation corn www.conslellat1on.corn Constellation Energy Generation (CEG) completed an examination of the tubing in the RE. Ginna Nuclear Power Plant (Ginna) steam generators during the Refueling Outage following the end of Cycle

43. Ginna Technical Specification 5.6. 7 requires, "A report shall be submitted within 180 days after the initial entry into MODE 4 following completion of an inspection performed in accordance with the Specification 5.5.8, Steam Generator (SG) Program." Attachment 1 contains the II R. E. Ginna Nuclear Power Plant Steam Generator Tube Inspection Report End of Cycle 43, Refueling Outage G1 R44, April

2023, 11 which documents the results of the examinations.

There are no regulatory commitments contained in this letter.

If you have any questions, please contact Justin Knowles at (315) 791-3393.

Respectfully, James D. Blankenship : R. E. Ginna Nuclear Power Plant Steam Generator Tube Inspection Report End of Cycle 43, Refueling Outage G1 R44, April 2023 cc:

NRC Regional Administrator, Region 1 NRC Project Manager, Ginna NRC Resident Inspector, Ginna

ATTACHMENT 1 R. E. Ginna Nuclear Power Plant Steam Generator Tube Inspection Report End of Cycle 43, Refueling Outage G1R44 April 2023

R. E. Ginna Nuclear Power Plant Steam Generator Tube Inspection Report End of Cycle 43, Refueling Outage G1R44 April 2023

~ Constellation

Steam Generator Tube Inspection Report Ginna EOC 43 Refueling Outage Page 2 of 17 R. E. Ginna Nuclear Power Plant Steam Generator Tube Inspection Report Introduction R. E. Ginna Nuclear Power Plant Technical Specification (TS) 5.6.7, Steam Generator Tube Inspection Report, states A report shall be submitted within 180 days after the initial entry into MODE 4 following completion of an inspection performed in accordance with the Specification 5.5.8, Steam Generator (SG) Program." This enclosure provides the 180-day report for the inspection performed during the Ginna Cycle 43 April 2023 refueling outage (G1R44), which was the most recent inspection of the Ginna replacement steam generators. This report follows the template provided in Appendix G to the Electric Power Research Institute (EPRI) Steam Generator Management Program: Steam Generator Integrity Assessment Guidelines, Revision 5 (Reference 1), which provides additional information beyond the Ginna TS 5.6.7 reporting requirements.

1. Design and operating parameters The original SGs at the R.E. Ginna Nuclear Power Plant (Ginna) were replaced in 1996 with two (2) recirculating design steam generators (SG) designed and fabricated by Babcock and Wilcox (BWI) of Cambridge, Ontario, Canada. The SGs have operated for four (4) fuel cycles since the previous inspection at End of Cycle 39 (G1R40). Table 1 provides the Ginna SG design and operating parameter information.

Steam Generator Tube Inspection Report Ginna EOC 43 Refueling Outage Page 3 of 17 Table 1: Ginna Steam Generator Design and Operating Parameters SG Model / Tube Material /

Number of SGs per Unit Babcock & Wilcox (Canada) Replacements / Alloy 690TT / 2 Number of tubes per SG /

Nominal Tube Diameter / Tube Thickness 4765 / 0.750 in. / 0.043 in Support Plate Style / Material Lattice Tube Support Grids and Fan Bars / 410 stainless steel Last Inspection Date April 2023 Effective full power months (EFPM) Since Last Inspection 66.96 EFPM [5.58 effective full power years (EFPY)]

(from G1R40 to G1R44)

Total Cumulative SG EFPY 25.0 EFPY (as of G1R44)

Mode 4 Initial Entry 4/27/2023 from G1R44 Observed Primary-to-Secondary Leak Rate No observed leakage Nominal Thot at Full Power Operation 607°F Degradation Mechanism Sub-Population Tubes located on the periphery of the tube bundle are in the highest cross-flow region and were considered in the G1R44 Degradation Assessment to be more susceptible to foreign object wear.

SG program guideline deviations since last Inspection None SG Schematic See Figure 1

Steam Generator Tube Inspection Report Ginna EOC 43 Refueling Outage Page 4 of 17 Figure 1: Tube Support Arrangement for Ginna B&W Replacement SGs Notes:

TEC - Tube End Cold Leg TEH - Tube End Hot Leg TSC - Top-of-Tubesheet Cold Leg TSH - Top-of-Tubesheet Hot Leg 01C - 08C - Lattice Grid Tube Supports on Cold Leg side 01H - 08H - Lattice Grid Tube Supports on Hot Leg side F01 - F10 - U-Bend Fan Bar Tube Supports F09 IFlO P:&r:El8l osc - - -

TEC F06 IFOS F02 FOl 08H 06H TEH

Steam Generator Tube Inspection Report Ginna EOC 43 Refueling Outage Page 5 of 17

2. The scope of the inspections performed on each SG (TS 5.6.7.a) and if applicable, a discussion of the reason for scope expansion Primary Side Eddy Current Scope The following inspections were performed during G1R44 to ensure that 100% of the tubes were inspected during the period as required by TS 5.5.8.d.2 Bobbin Probe Eddy Current Testing (ECT) Examinations:

o 100% of the in-service tubes will be inspected full length, tube-end hot (TEH) to tube-end cold (TEC), using the bobbin probe.

Array Probe ECT Examinations:

o 50% peripheral array (X-Probe) examination on the Hot and Cold Legs from the first support to the tube end for potential foreign objects and associated wear (peripheral locations are where crossflow velocities are the highest)

Special Interest Examinations o 100% of the hot leg tubesheet G1R40 dent/dings 2V (Array and +Point')

o 20% random sample of the cold leg tubesheet G1R40 dent/dings 2V (Array and

+PointTM)

There was no scope expansion required or performed during the G1R44 eddy current inspections.

Primary Side Visual Inspection Scope The primary side channel head (hot and cold leg) of both steam generators was visually inspected using a remote operated camera in accordance with Ginna inspection procedures. The channel head general area and cladding was inspected for the following: through holes or breaches that would expose carbon steel base material under the cladding, rust colored discoloration or stains visible on cladding surface, and channel head cladding degradation such as cracks or significant deformation.

The tubesheet, tube ends, and tube plugs were inspected for the following: cracking, degradation, water leakage, boron deposits, and tube sheet or tube end deformation. No degradation was observed in any of these areas in either steam generator.

The divider plate was visually inspected from both hot and cold legs using a remote camera specifically looking for the following: cracks on the divider plate surface, surface deformation, foreign material that may mask any degradation, and any other degradation. Special attention was made when inspecting the weld deposit seat bar, divider plate weld, divider plate corner windows, and the divider plate weld heat affected zone. No degradation was observed in any of these areas in either steam generator.

Secondary Side Inspection Scope Secondary side inspections were performed with a variety of remote tooling. For each steam generator, a visual inspection (top of tubesheet) was performed after sludge lancing including:

100% of the annulus to a minimum of 6 tubes deep 100% of the no-tube lane to a minimum of 6 tubes deep Blowdown and drain holes Shroud supports

Steam Generator Tube Inspection Report Ginna EOC 43 Refueling Outage Page 6 of 17 Inspection of tube support structures (1st support only)

In-bundle inspection of previously-identified foreign objects at the top of tubesheet In-bundle inspection of ECT-detected Possible Loose Part (PLP) at the top of tubesheet A steam drum and upper internals inspection was performed on both steam generators. The steam drum and upper internals inspection included:

Upper Internals Visual Inspection o Primary moisture separators o Secondary moisture separators o Steam outlet venturi o Secondary deck seal skirt o General area structures, hatches, and welds Laser profilometry of all secondary moisture separator base plates and sidewalls

3. The nondestructive examination techniques utilized for tubes with increased degradation susceptibility (TS 5.6.7.b)

Tubes located on the periphery of the tube bundle are in the highest cross-flow region and were considered in the Degradation Assessment to be more susceptible to foreign object wear, especially near the tubesheet where most foreign objects are located. As a compensatory measure, tubes in this region were tested with an array (X-probe) which has increased sensitivity for detection of foreign objects and foreign object wear close to the tubesheet. This scope encompassed 50% of the hot and cold leg tubes from the tube end to the 1st tube support (01C/01H).

4. For each degradation mechanism found: The nondestructive examination technique utilized for each degradation mechanism found (TS 5.6.7.c.1)

Steam Generator eddy current examination techniques used (see Table 2 below) were qualified in accordance with Appendix H or Appendix I of the EPRI PWR SG Examination Guidelines Revision 8. Each examination technique was evaluated to be applicable to the tubing and the degradation mechanisms found in the Ginna SGs during G1R44.

Steam Generator Tube Inspection Report Ginna EOC 43 Refueling Outage Page 7 of 17 Table 2: Non-Destructive Examination (NDE) Techniques for Each Existing Degradation Mechanism Found During G1R44 Location Degradation Mechanism Orientation Probe EPRI ETSS1 EPRI ETSS1 Rev Fan Bar (U-bend)

Wear Vol Bobbin Array Array I-96041.1 I-17909.1 I-17909.4 7

1 1

Lattice Grid (Horz.

Support)

Wear Vol Bobbin Array

+Point 96004.1 I-11956.3 96910.1 14 3

12 Foreign Object at top of tubesheet or lattice grid Wear Vol Bobbin Array Array

+Point 27091.2 17901.1 17901.3 27901.1 2

0 0

1

1.

ETSS - Examination Technique Specification Sheet

5. For each degradation mechanism found: the location, orientation (if linear), measured size (if available), and voltage response for each indication. For tube wear at support structures less than 20 percent through-wall, only the total number of indications needs to be reported (TS 5.6.7.c.2)

Volumetric wear at support structures was the primary degradation mechanism detected during the G1R44 inspection. The wear indications detected were located at horizontal lattice grid tube support structures. Table 3 provides the number of indications reported during the G1R44 inspection.

Table 3: Number of Indications Detected for Each Degradation Mechanism in G1R44 Degradation Mechanism SGA SGB Total Indications Indications Lattice Grid Support Wear 7

15 22 Foreign Object Wear 2

5 7

Table 4 provides a listing of all the lattice grid wear indications 20%TW or greater reported during the G1R44 inspection including the measured depths from the array probe. Only two indications in SG A were sized at 20% TW or greater.

Steam Generator Tube Inspection Report Ginna EOC 43 Refueling Outage Page 8 of 17 Table 4: G1R44 Lattice Grid Wear Indications >20%TW SG Row Col Location Array Depth

(%TW)

Axial Extent (Inches)

Voltage (Bobbin)

A 30 50 04H-0.36 22 0.26 0.25 A

41 87 08H+1.13 20 0.31 0.17 B

No indications in SG B >20%TW Table 5 provides a listing of all the foreign object wear indications reported during the G1R44 inspection including the measured voltages, depths, and measured dimensions from the plus-point probe. Indications of tube wear at support structures are provided regardless of percent through-wall depth.

Table 5: G1R44 Foreign Object Wear Indications SG Row Col Location Array Voltage Array Depth

(%TW)

Axial Extent (Inches)

Circumferential Extent (Inches)

A 53 85 03H-2.07 0.12 19 0.28 0.29 A

91 51 05H+0.35 0.39 35 0.28 0.29 B

2 78 02H-1.84 0.59 25 0.20 0.44 B

3 75 02H-1.55 0.56 24 0.30 0.37 B

3 75 02H-1.45 0.47 22 0.25 0.29 B

31 83 03C-1.85 4.10 551 0.26 0.44 B

31 83 03C-1.00 0.45 221 0.42 0.22

1. Tube plugged in G1R44.

6. For each degradation mechanism found: A description of the condition monitoring assessment and results, including the 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 (TS 5.6.7.c.3). Discuss any degradation that was not bounded by the prior operational assessment in terms of projected maximum flaw dimensions, minimum burst strength, and/or accident induced leak rate. Provide details of any in situ pressure test.

A condition monitoring (CM) assessment was performed as required by the Ginna SG program.

The tube degradation detected during the G1R44 inspection was due to lattice grid wear and foreign object wear at lattice grid supports. The deepest indication for each mechanism met condition monitoring analytically as shown in Figures 2, 3a and 3b. The margin to the structural and condition monitoring limit curve for each detected wear indication can be determined from Figures 2, 3a and 3b. The CM limit curves include uncertainties for material properties and NDE depth sizing. The deepest flaws have a depth less than the conservatively-determined CM limit for all degradation mechanisms; therefore, the structural integrity performance criterion was met

Steam Generator Tube Inspection Report Ginna EOC 43 Refueling Outage Page 9 of 17 for the operating interval prior to G1R44. A summary of the CM results from G1R44 as compared to the Operational Assessment (OA) predictions from the most recent prior inspections (G1R38 and G1R40) is provided in Table 6.

Figure 2: Condition Monitoring Results for Lattice Grid Wear 100 00 80 70 t 60

.I! a.

m Q

E 50 E

,,'II

ll ~o Iii.I C z: 30 20 10 0

\\.

0.0 C

fl OS Array, ETSS 1-11956..3

-,_ *lm'ill C

Fl ll!l 1.0 1 5 2.0 25

Steam Generator Tube Inspection Report Ginna EOC 43 Refueling Outage Page 10 of 17 Figure 3a: Condition Monitoring Results for Foreign Object Wear, ETSS 17901.3 (SG B)

Figure 3b: Condition Monitoring Results for Foreign Object Wear, ETSS 17901.1 (Both SGs)

~

I-

~

.s::. a.

Q) 0 E

E

!E w

0 z

.s::. a.

Q) 0 E

E

!E w

0 100 90 80 70 60 50 40 30 20 10 0

100 90 80 70 60 50 40 Z

30 20 10 0.0 Array, ETSS H-17901.3

~

~~8~1~:~,:--

Plugged at G1R44 0.5 1.0 1.5 Axial Extent (inches)

Array, ETSS H-17901.1 a--- sGBR31-C8322%1W Plugged at G1R44 -

• Limit Flaws -------------------

2.0

• Limit Flaws 2.5 0 -+--------~--------~-------~~-------~-------~

0.0 0.5 1.0 1.5 2.0 2.5 Axial Extent (inches)

Steam Generator Tube Inspection Report Ginna EOC 43 Refueling Outage Page 11 of 17 Table 6: Comparison of Prior OA Projections to As-Found Results Parameter G1R44 Projection1 G1R44 As-Found1 Inspection Interval 5.71 EFPY (from G1R40) 5.58 EFPY Fan Bar Wear Maximum Depth 33.02 %TW (from G1R38)2 None Lattice Grid Wear Maximum Depth 32.74 %TW (from G1R40) 33.44 %TW (from G1R38)2 22 %TW Tube-to-Tube Wear 37.87 %TW (from G1R38)2 None Foreign Object Wear Maximum Depth

< 57.1 %TW 55 % TW

1.

NDE Depths are reported for both projected and as found results

2.

G1R38 projections are to bound approximately 25% of the tube population that was not inspected in G1R40 and was last inspected in G1R38.

Volumetric wear indications will leak and burst at essentially the same pressure; therefore, accident-induced leakage integrity is also demonstrated. Operational leakage integrity was demonstrated by the absence of any detectable primary-to-secondary leakage during the operating interval prior to G1R44. Because tube integrity was demonstrated analytically, in-situ pressure testing was not required nor performed during G1R44. There were no tube pulls planned or performed during G1R44.

7. For each degradation mechanism found: The number of tubes plugged during the inspection outage (TS 5.6.7.c.4). Also, provide the tube location and reason for plugging.

Table 7 provides the number of tubes plugged for each degradation mechanism detected during G1R44. Table 8 provides the location and reason for tubes plugged during G1R44.

Table 7: Number of Tubes Plugged for Each Degradation Mechanism in G1R44 (TS 5.6.7.c.4)

Degradation Mechanism 1A SG 1B SG Total Fan Bar Wear 0

0 0

Lattice Grid Wear 0

0 0

Foreign Object Wear 0

1 1

Preventative 0

3 3

Total Plugged during G1R44 0

4 4

Steam Generator Tube Inspection Report Ginna EOC 43 Refueling Outage Page 12 of 17 Table 8: Tubes Plugged for Each Degradation Mechanism in G1R44 SG Row Col Stabilizer Reason for Repair Yes / No Leg B

5 75 Yes Hot Preventative plug for PLP1 @ 02H-1.09 B

6 74 Yes Hot Preventative plug for PLP1 @ 02H-1.22 B

31 83 Yes Cold Plugged for 55%TW FO2 wear @ 03C-1.85 B

33 83 Yes Cold Preventative plug for PLP1 @ 03C-1.24

1.

PLP - Possible Loose Part

2.

FO - Foreign Object

8. An analysis summary of the tube integrity conditions predicted to exist at the next scheduled inspection (the forward-looking tube integrity assessment) relative to the applicable performance criteria, including the analysis methodology, inputs, and results (TS 5.6.7.d). Include the effective full power months of operation permitted for the current operational assessment.

Summary Based on application of conservative lattice grid wear growth rates, the condition of the Ginna SG tubes has been analyzed with respect to continued operability of the SGs without exceeding the SG tube integrity performance criteria at the next scheduled SG eddy current inspection no later than G1R49.

Based on foreign object susceptibility the condition of the Ginna SG tubes has been analyzed with respect to continued operability of the SGs without exceeding the SG tube integrity performance criteria at the next scheduled SG sludge lancing, FOSAR, and steam drum moisture separator inspection no later than G1R47.

Lattice Grid Wear Operational Assessment (OA)

Due to the smaller number of indications, a deterministic approach is appropriate for performing the operational assessment. A total of 22 lattice grid wear indications were detected in 20 tubes with the deepest indication measuring 22%TW, with all but 4 newly reported at G1R44. Historical data from G1R40 and G1R38 was reviewed for these 18 new indications with 5 having a precursor bobbin signal present during the last inspection at G1R40, including the deepest wear. This was the first inspection where Array was used to confirm and size all LGW indications, and +Point' was used only on the repeat indications to determine growth rates. It is noted that where both probes were used to depth size, the Array probe consistently oversized the flaws by an average of 7%TW Beginning of cycle (BOC) Non-Destructive Examination (NDE) Depth (BOCNDE) = 22 %TW (the largest returned to service lattice grid wear indication identified during G1R44)

Cycle Length = 7.3 EFPY o Bounds the 7.25 EFPY identified through G1R49.

Growth Rate = 1.0 %TW/EFPY o Bounds the maximum lattice grid wear growth rate of 0.18 %TW/EFPY and is comparable to the upper 95th growth rate from similar BWXT RSGs

Steam Generator Tube Inspection Report Ginna EOC 43 Refueling Outage Page 13 of 17 Length = 2.5 o Bounds the maximum lattice grid length of 2.04 sized during G1R44.

Normal Operating Pressure Differential (NOPD) = 1461 psid o Bounding NOPD from the Degradation Assessment (DA) o The BOC NDE depth (BOCNDE) is first adjusted upward to equal the upper 95th percentile structural depth (BOCSD) using ETSS 11956.3 parameters:

= ( 1.03) 1.22 + (1.645 2.42) = 25.4 %

Then the growth rate is applied over a 5-cycle operating length of 7.3 EFPY to determine the end-of-cycle structural depth (EOCSD):

= +

= 25.4 %+ 1.0 %

7.3 = 32.7 %

For an assumed bounding length of 2.5 the allowable structural depth at 3 times a NOPD of 1461 psid is 51.6%TW. Since the projected depth of 32.7%TW is less than the structural depth, there is reasonable assurance that the Accident Induced Leakage Performance Criteria (AILPC) will be satisfied through G1R49.

Tube Wear from Existing, Remaining, and New Foreign Objects OA In G1R44, one tube was plugged for FO Wear of 55%TW at a support structure with a ECT PLP still present.

The eddy current examinations included tubesheet array probe inspections of all tubes in the high-flow regions at the periphery and no-tube lane on both the hot and cold sides in both steam generators.

With these extensive inspections and subsequent object removal, there is reasonable confidence that no object capable of causing significant tube degradation remains in the tube bundle adjacent to in-service tubes. Despite the extensive inspections and removal of multiple objects, the OA still considers the potential for tube degradation from parts remaining in the bundle or potentially entering the bundle during the next operational period. For the purposes of the OA, the discussion of foreign objects and associated wear will be segregated into the following categories:

Foreign objects known to be remaining in the steam generators:

All metallic or potential metallic objects that could cause wear were either removed from SGA and SGB or had the affected tubes in contact with such objects plugged and stabilized during G1R44. The disposition of all objects found is shown in Table 11.

Foreign objects that may enter the steam generators:

The material removed from the sludge lancing strainer during G1R44 illustrates the types of FOs with potential to enter the SGs during the next operating interval. Some of the objects found in the lancing strainer exhibit a surface texture similar to that of the degraded regions of the moisture separators. Assuming these are objects coming from the moisture separators and that they continue to enter the lower elevations of the SG until the separator degradation can be remediated, wear evaluations were performed on those as well as gasket type material, using dimensions from the objects found in the lancing strainer.

Steam Generator Tube Inspection Report Ginna EOC 43 Refueling Outage Page 14 of 17 For the gasket pieces, limiting dimensions were used based on the lengths observed in the strainer basket and typical gasket widths and thicknesses.

For the separator pieces due to the variability in shapes and dimensions, two potential object types were evaluated assuming a bounding length of 1.0 and an average thickness of 0.012 based on measurements from the pieces identified in the lancing strainer.

For assumed bounding FO conditions and a wear length of 1.0, the allowable structural depth at 3 times a NOPD of 1461 psid is 54.2%TW. The results of the evaluations show that with the right set of dimensions, certain parts expected to enter the SG caught in the highest flow region have the potential to cause enough wear after 4 or more cycles that they could challenge the structural limit. For this reason, sludge lancing, top of tubesheet FOSAR, and steam drum moisture separator inspections will be performed no later than G1R47. The next eddy current inspection will be performed no later than G1R49.

Table 9: Comparison of OA Projections at Next SG Inspection to Structural Limits Degradation Mechanism (wear)

Maximum depth (%) Predicted at Next Inspection Structural limit depth (%)

Lattice Grid support 32.7 51.6 Existing FO Wear No Growth (FO removed) 54.2 Remaining FOs All FOs identified capable of wear were removed or adjacent tubes plugged New FOs

<54.2 for 3-cycles (4.29 EFPY)

9. The number and percentage of tubes plugged to date, and the effective plugging percentage in each SG (TS 5.6.7.e).

Table 10 shows the number of tubes plugged before and after the G1R44 outage and the percentage of tubes currently plugged (total and effective). No sleeves have been installed in the Ginna replacement SGs.

Table 10: Tube Plugging to Date (Number and Percentage per SG) (TS 5.6.7.e)

SG A SG B Total Plugged prior to G1R44 1

5 6

Plugged during G1R44 0

4 4

Stabilized during G1R44 0

4 4

Total Plugged through G1R44 1

9 10 Total/Effective Percent Plugged through G1R44 0.02%

0.19%

0.1%

Steam Generator Tube Inspection Report Ginna EOC 43 Refueling Outage Page 15 of 17

10. The results of any SG secondary-side inspection (TS 5.6.7.f). The number, type, and location (if available) of loose parts that could damage tubes removed or left in service in each SG.

Secondary Side Scope:

For each steam generator, a visual inspection (top of tubesheet) was performed after sludge lancing including:

100% of the annulus to a minimum of 6 tubes deep 100% of the no-tube lane to a minimum of 6 tubes deep Blowdown and drain holes Shroud supports Inspection of tube support structures (1st support only)

In-bundle inspection of previously identified foreign objects as directed by Engineering In-bundle inspection of ECT-detected PLPs as directed by Engineering A steam drum and upper internals inspection was performed on both steam generators. The steam drum and upper internals inspection included:

Upper Internals Visual Inspection o Primary moisture separators o Secondary moisture separators o Steam outlet venturi o Secondary deck seal skirt o General area structures, hatches, and welds Laser profilometry of all secondary moisture separator base plates and sidewalls Secondary Side Visual Inspections of Tubesheet and FOSAR Secondary side tubesheet visual inspections were performed following sludge lancing activities in both SGs. High flow regions of the annulus, no tube lane and periphery (a minimum of 6 tubes deep) were visually inspected for foreign material. Additionally, eight columns for the full depth of the tube bundle interior (kidney region) were evaluated for sludge lancing effectiveness and sludge accumulation.

Water lancing was performed in both SGs followed by secondary side visual inspections of the periphery, no-tube lane, and inner bundle passes. The TTS sludge heights were measured from bobbin ECT results. Sludge accumulation was primarily on the hot leg between rows 10 and 50 and columns30-110.

Foreign object search and retrieval (FOSAR) was performed on a variety of foreign objects identified from visual inspections as well as ECT PLP and FO Wear indications as summarized in Table 11. All metallic or potential metallic objects that could cause wear were either removed from SGA and SGB or had the affected tubes in contact with such objects plugged and stabilized during G1R44.

Steam Generator Tube Inspection Report Ginna EOC 43 Refueling Outage Page 16 of 17 Table 11: Foreign Object Summary SG Row Col Location Ref ID G1R44 Disposition Material Status A

80 78 76 79 77 75 42 42 42 41 41 41 TSH 22 Object identified with visual inspections and was removed. All affected and bounding tubes are NDD1 with ECT.

No further actions required in G1R44.

Flex Gasket Removed A

79 77 75 80 78 76 95 95 95 94 94 94 TSH 25 Object identified with visual inspections and was removed. All affected and bounding tubes are NDD1 with ECT.

No further actions required in G1R44.

Flex Gasket Removed A

4 5

36 37 TSC 27 Object was removed and confirmed as fibrous which is not harmful to tube integrity.

ECT was NDD1 with Bobbin and Array.

No further actions required at G1R44.

Fibrous Object Removed A

69 68 67 67 66 67 TSH 28 FO is a small wire bristle and due to the small size (diameter and length), it does not pose a threat to tube integrity and was not able to be removed. ECT was NDD1 on affected and bounding tubes.

No further actions required at G1R44.

Wire Bristle Remains in place B

53 54 11 12 TSC +12-14 12 Object was confirmed as machine curl elevated ~12-14 off of the tubesheet and was removed from the SG. ECT was NDD1 on affected and bounding tubes.

No further actions required at G1R44.

Machine Curl Removed B

41 40 79 78 TSH 14 Object identified with visual inspections and was removed. All affected and bounding tubes are NDD1 with ECT.

No further actions required in G1R44.

Flex Gasket Removed B

31 33 83 83 03C-1.85 17 Bobbin PLP and DSI2 confirmed as PLP and WAR3 with Array. Two FO Wear flaws, 55%TW (ETSS, 17901.3) and 22%TW (ETSS, 17901.1). 31-83 and 33-83 plugged and stabilized. Bounding tubes do not need plugging as PLPs are contained within support.

PLP Affected tubes plugged and stabilized

1.

NDD - No Degradation Detected

2.

DSI - Distorted Support Indication

3.

WAR - Wear Indication Steam drum visual inspections Visual examinations were performed in both SGs to address the material condition of the subcomponents in this region. The primary and secondary separators were of particular interest due to susceptibility to flow accelerated corrosion (FAC) and measured degradation of the secondary baseplates using laser profilometry from G1R40. The G1R44 examinations confirmed that the

Steam Generator Tube Inspection Report Ginna EOC 43 Refueling Outage Page 17 of 17 separator FAC is continuing, and it appears that portions of the secondary sidewall and primary separators have degraded enough such that through-wall holes have been identified.

In addition to the visual examinations, laser profilometry was performed in all secondary baseplates in each SG to measure the percentage through-plate thickness (%TP) remaining for calculating degradation growth from G1R40, and on all secondary sidewall locations to get a baseline thickness measurement for future trending.

Prior to the 2023 (G1R44) SG inspection, outage contingency plans were in place to repair the secondary moisture separator baseplates with welded patch plates. Material and schedule allowed for a total of 40 baseplate repairs. The priority for repairs at G1R44 was made through a combination of linear and probabilistic projections.

11. The scope, method, and results of secondary-side cleaning performed in each SG Prior to the secondary side FOSAR inspections, sludge, scale, foreign objects, and other deposit accumulations at the top of the tubesheet were removed as part of the top of tubesheet water lancing process. The weight of deposits removed from each SG by this cleaning process is provided in Table 12. Ginna had operated 4 cycles since the last time sludge lancing was performed during G1R40. A total of 56 lbs. of sludge was removed from both the SGs along with a variety of foreign objects such as flexitallic gaskets, wire, machining remnants as well as what is potentially small fragments of degraded moisture separators.

Table 12: G1R44 SG Deposit Removal Weights SG Weight A

33 lbs.

B 23 lbs.

Total 56 lbs.

12. The results of primary side component visual inspections performed in each SG.

Visual Inspection of Installed Tube Plugs and Tube-to-Tubesheet Welds All previously installed tube plugs (6) were visually inspected for signs of degradation and leakage.

The tube-to-tubesheet welds were visually inspected during eddy current. No degradation or anomalies were found.

SG Channel Head Bowl Visual Inspections Each SG hot and cold leg primary channel head was visually examined for evidence of breaches in the cladding or cracking in the divider-to-channel head weld and for evidence of wastage of the carbon steel channel head. No evidence of cladding breaches, wastage, or corrosion in the channel head was identified. Also, no cracking in the divider-plate-to-channel-head weld was identified.

References

1. Steam Generator Management Program: EPRI Steam Generator Integrity Assessment Guidelines, Revision 5, EPRI, Palo Alto, CA, December 2021 (EPRI Doc. No. 3002020909)