ML25309A014

Summary of Second Conference Call Regarding Steam Generator Tube Inspections

ML25309A014
Person / Time
Site:	Palisades
Issue date:	11/06/2025
From:	Justin Poole Plant Licensing Branch III
To:	Holtec Palisades
References
EPID L-2024-NFO-0008
Download: ML25309A014 (1)

Text

November 6, 2025 Site Vice President Holtec Palisades, LLC Palisades Nuclear Plant 27780 Blue Star Memorial Highway Covert, MI 49043-9530

SUBJECT:

PALISADES NUCLEAR PLANT -

SUMMARY

OF SECOND CONFERENCE CALL REGARDING STEAM GENERATOR TUBE INSPECTIONS (EPID L-2024-NFO-0008)

Dear Sir or Madam:

On September 3, 2024, the U.S. Nuclear Regulatory Commission staff and representatives from Holtec Decommissioning International, LLC (Holtec) participated in a conference call to discuss the steam generator (SG) tube inspection activities at the Palisades Nuclear Plant. At the time of the call, the SG inspections were not substantially complete, and Holtec indicated that due to logistical issues, inspection activities would not be complete for many months. A summary of the conference call is in the Agencywide Documents Access and Management System (ADAMS) under Accession No. ML24267A296. On August 14, 2025, the NRC staff held a second conference call with Holtec, when the SG inspections and in-situ pressure testing were essentially complete. At the time of the call, the plant was in decommissioning status; however, the owner was performing these inspections as part of an effort to resume full power operations.

On August 25, 2025, the plant transitioned to an operational status.

A summary of the August 14, 2025, conference call is provided as an enclosure to this letter.

If you have any questions, please contact me at 301-415-2048 or via e-mail at Justin.Poole@nrc.gov.

Sincerely,

/RA/

Justin C. Poole, Project Manager Plant Licensing Branch III Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-255

Enclosure:

Summary of Conference Call cc: Listserv

Enclosure

SUMMARY

OF SECOND CONFERENCE CALL HOLTEC PALISADES, LLC PALISADES ENERGY, LLC PALISADES NUCLEAR PLANT DOCKET NO. 50-255 STEAM GENERATOR TUBE INSPECTIONS On September 3, 2024, the U.S. Nuclear Regulatory Commission (NRC) staff and representatives from Holtec Decommissioning International, LLC (Holtec, the licensee)1 participated in a conference call to discuss the steam generator (SG) tube inspection activities at Palisades Nuclear Plant (Palisades, PNP). At the time of the call, the SG inspections were not substantially complete, and the licensee indicated that due to logistical issues, inspection activities would not be complete for many months. A summary of the conference call is in the Agencywide Documents Access and Management System under Accession No. ML24267A296.

On August 14, 2025, the NRC staff held a second conference call with the licensee, when the SG inspections and in-situ pressure testing were essentially complete. At the time of the call, the plant was in decommissioning status; however, the owner was performing these inspections as part of an effort to resume full power operations. On August 25, 2025, the plant transitioned to an operational status. The licensee provided the following information in response to an NRC request for a conference call to discuss the final SG inspection results.

Palisades has 2 Combustion Engineering Model 2530 replacement SGs. Each SG has 8,219 mill-annealed, Alloy 600 tubes. The tubes have an outside diameter of 0.75 inches, and a wall thickness of 0.042 inches. Stainless steel, eggcrate, lattice-type tube supports; diagonal straps; and vertical straps support the tubes at various locations. The tubes were expanded through the full depth of the tubesheet during fabrication.

Updated responses to questions 1 through 12 from the September 2024 call are provided below.

1. Discuss any trends in the amount of primary-to-secondary leakage observed during the recently completed cycle.

No change from ML24267A296 response

2. Discuss whether any secondary side pressure tests were performed during the outage [i.e.,

during the current shutdown period] and the associated results.

No change from ML24267A296 response 1 On July 24, 2025, the NRC issued an order approving and conforming amendment reflecting the transfer of operating authority from Holtec Decommissioning International, LLC to Palisades Energy, LLC (Package, ML25167A245). Holtec Palisades, LLC, remains the licensed owner of PNP.

3. Discuss any exceptions taken to the industry guidelines.

No change from ML24267A296 response

4. For each SG, provide a description of the inspections performed including the areas examined and the probes used (e.g., dents/dings, sleeves, expansion-transition, U-bends with a rotating probe), the scope of the inspection (e.g., 100 percent of dents/dings greater than 5 volts and a 20 percent sample between 2 and 5 volts), and the expansion criteria.

Updated from ML24267A296 response.

There were three groups of tubes inspected at 1D28: tubes in service at 1D28, tubes out of service at 1D28, and tubes that required sleeving at 1D28.

1. Tubes in service at 1D28

a. Bobbin Probe

i. Full length eddy current testing (ECT) bobbin coil examination of all in-service tubes (except row 1, 2, and 3 U-bends) in both SGs.

b. ECT +PointTM coil examinations (both SGS):

i. 100 percent of rows 1, 2, and 3 U-bends ii. 100 percent of hot leg from TTS + 4 to a minimum of 13.5 below the bottom of the expansion transition.

iii. 100 percent of free span dings >5V between the hot-leg tubesheet (TSH) and cold-leg tubesheet (TSC).

iv. 100 percent of >2V dents at eggcrate, diagonal bar, and vertical strap intersections between TSH and TSC.

v. 50 percent of historical percent through-wall (TW) calls at diagonal bars and vertical straps. The original scope was 25 percent of historical calls which was expanded upon confirmation of crack like indications at vertical straps. Since historical percent TW calls have only been inspected once every 4 inspections, separated into 4 populations of 25 percent, the expansion was to the next 25 percent population (i.e., indications that were last inspected 3 outages ago).

There were no crack like indications identified in the expanded scope therefore no further expansion was needed.

vi. 100 percent of historical trackable (TRA) indications vii. The outer three peripheral tubes at the cold leg from the top of the tubesheet (TTS)+4 to the TTS-2 for detection of possible loose parts or wear signals. The periphery region is defined to be the outer three tubes exposed to the annulus, all tubes in rows 1 through 4, and the inner three tubes around the stay cylinder region.

c. Special interest examinations (+Point' coil):

i. All current outage bobbin I-code signals ii. All eggcrate bobbin percent TWs called during the current outage iii. All wear scars 40 percent TW by bobbin iv. All new percent TWs indications regardless of location

v. The hot leg square bend region of tubes surrounding SG B tube R99-C140 vi. All bobbin foreign object and foreign object wear indications vii. Bounding of foreign object signals (new in 1D28 and RPC [rotating pancake coil]-confirmed possible loose parts (PLPs) from 1R27) and foreign object wear at all elevations. These bounding exams continued until a one tube deep perimeter has been examined in which no PLP or foreign object wear indication is identified.

viii. Bounding of locations in tubes recently plugged that had PLP indication or foreign object wear near the TTS.

ix. All tube regions unable to be examined effectively with bobbin probe due to data quality concerns.

d. Special interest examinations (Ghent probe)

i. Sample of locations in SG A (60 tubes) to confirm +Point' single axial indications (SAIs) and single circumferential indications (SCIs).

This was not a planned scope and was done to address the large number of crack like indications identified at 1D28

2. Tubes De-plugged for inspection at 1D28

a. All de-plugged tubes were inspected with the same scope as the in-service tubes at 1D28 (except for the cold leg de-plugged tubes that had CE Rolled plugs removed - these were all inspected at TSC with +Point because they had never before been inspected with ECT).

Of the 732 tubes that were sleeved in 1D28, 4 were subsequently plugged during 1D28. These tubes were plugged either due to the installed position of the sleeve or an issue with the sleeve expansion results.

3. Tubes that were sleeving candidates at 1D28

a. Bobbin Probe

i. All installed sleeves for position verification.

b. +Point' coil

i. All sleeves for baseline data.

The scopes/results discussed address 100 percent of the population of interest except for items 1.b.v and 1.d where the following scope expansions were performed in 1D28:

Expansion of the +Point' inspections for the historical percent TW indications at vertical straps and diagonal bars from 25 percent to 50 percent to address the crack like indications identified in the initial 25 percent population (Item 1.b.v above). There were no crack like indications identified in the expanded scope therefore no further expansion was needed.

Expansion of using the Ghent probe in SG A as additional confirmation of crack like indications identified in 1D28 (item 1.d above).

5. For each area examined (e.g., tube supports, dent/dings, sleeves, etc.), provide the following:

a. A summary of the number of indications identified to date for each degradation mode (e.g., number of circumferential primary water stress corrosion cracking indications (PWSCC) at the expansion transition). Provide the number of tubes with each degradation mechanism in addition to the number of indications.

Updated from ML24267A296 response Degradation Mechanisms - Number of Indications / Tubes SG Location Type Indications Tubes A

TSH Axial ODSCC 17 16 A

TSH Axial PWSCC 52 51 A

TSH Circ PWSCC 29 10 A

TSH Circ ODSCC 73 60 A

TSH Volumetric 24 21 A

TEC to TEH Wear > 40 5

5 A

Tube Supports Axial ODSCC 900 608 A

Dent at Tube Supports Axial PWSCC 1

1 A

Freespan Axial ODSCC 2

2 B

TSH Axial ODSCC 10 9

B TSH Axial PWSCC 10 10 B

TSH Circ PWSCC 1

1 B

TSH Circ ODSCC 18 15 B

TSH Volumetric 7

6 B

TEH to TEC Wear > 40 3

3 B

Tube Supports Axial ODSCC 313 220 B

Freespan Axial ODSCC 1

1 Total 1466 1039 TEH - Tube end hot leg TEC - Tube end cold leg There were three indications of axial outside diameter stress corrosion cracking (ODSCC) in the freespan region identified in 1D28, two in SG A and one in SG B.

None of these indications were associated with a ding or dent.

b. For the most significant indications in each area, provide an estimate of the severity of the indication (e.g., voltage, depth, and length of the indication), including whether tube integrity (structural and accident induced leakage integrity) was maintained during the previous operating cycle. In addition, discuss any analyses performed specifically for the most significant indications to demonstrate tube integrity.

Updated from ML24267A296 response Most Significant Indications in Each Area Item SG Location Type Indication Location Voltage (V)

Depth

(%TW)

Length (in.)

Structural Integrity Leakage Integrity Structural Integrity Analysis Leakage Integrity Analysis 1

A TSH Axial ODSCC 32-115-TSH+0.57 4.29 91(1) 0.45 Maintained Maintained In Situ Pressure Test In Situ Pressure Test 2

A TSH Axial PWSCC 107-80-TSH-0.16 2.65 78 0.19 Maintained Maintained Condition Monitoring Condition Monitoring 3

A TSH Circ PWSCC 36-23-TSH-11.04 5.47 90 0.6 Maintained Maintained Condition Monitoring Analytical Analysis (3) 4 A

TSH Circ ODSCC 109-102TSH-0.06 4.45 90 1.03 Maintained Maintained In Situ Pressure Test In Situ Pressure Test 5

A TSH Volumetric 126-105-TSH+0.29 0.61 46 0.27 Maintained Maintained Condition Monitoring Condition Monitoring 6

A TEC to TEH Wear 40 54 DBH+0.09 2.88 41 (2)

Maintained Maintained Condition Monitoring Condition Monitoring 7

A Tube Supports Axial ODSCC 15-122-01H+0.8 2.26 85(1) 0.77 Maintained Maintained In Situ Pressure Test In Situ Pressure Test 8

A Dent at Tube Supports Axial PWSCC 22 VS4+0.93 0.71 78 0.27 Maintained Maintained Condition Monitoring Condition Monitoring 9

A Freespan Axial ODSCC 94-139-07C+1.59 0.45 51.3(1) 0.36 Maintained Maintained Condition Monitoring Condition Monitoring 10 B

TSH Axial ODSCC 30 TSH+0.75 2.22 80.1(1) 0.6 Maintained Maintained In Situ Pressure Test In Situ Pressure Test 11 B

TSH Axial PWSCC 42-103-TSH-1.7 2.47 76 0.37 Maintained Maintained Condition Monitoring Condition Monitoring 12 B

TSH Circ PWSCC 54-25TSH-11.82 0.89 67 0.22 Maintained Maintained Condition Monitoring Condition Monitoring 13 B

TSH Circ ODSCC 45-52-TSH-0.03 1.69 81 0.37 Maintained Maintained Condition Monitoring Condition Monitoring 14 B

TSH Volumetric 127 TSH+0.19 0.68 49 0.21 Maintained Maintained Condition Monitoring Condition Monitoring Most Significant Indications in Each Area Item SG Location Type Indication Location Voltage (V)

Depth

(%TW)

Length (in.)

Structural Integrity Leakage Integrity Structural Integrity Analysis Leakage Integrity Analysis 15 B

TEH to TEC Wear 40 48-9-VS4+0.26 3.2 44 (2)

Maintained Maintained Condition Monitoring Condition Monitoring 16 B

Tube Supports Axial ODSCC 24-115-01H+0.53 1.17 71.3(1) 0.93 Maintained Maintained In Situ Pressure Test In Situ Pressure Test 17 B

Freespan Axial ODSCC 62 VS5+3.55 0.46 51.7(1) 0.25 Maintained Maintained Condition Monitoring Condition Monitoring Notes:

1. Depth Calculated with Eddy Current Technique Specification Sheet (ETSS) Voltage Correlation with 11% offset factored in per exemption noted in question 3 above.

2. Bobbin probe results provided, not qualified for length sizing

3. Flaw is exempted from in situ per Electric Power Research Institute (EPRI) In Situ Pressure Test Guidelines Section D.2.2.

Leakage is addressed analytically.

DBH - Diagonal Bar Hot Leg VS - Vertical Strap

c. Discuss whether any location exhibited a degradation mode that had not previously been observed at this location at this unit (e.g., observed circumferential primary water stress corrosion cracking at the expansion transition for the first time at this unit).

No change from ML24267A296 response.

6. Describe repair/plugging plans. Identify the largest volumetric/wear depth from the tubes that were de-plugged and returned to service.

Updated from ML24267A296 response.

Repair Plans (Includes de-plugged tubes that required sleeves) The acceptance criteria for tubes that were unplugged in 1D28 for planned return to service was not modified from the standard technical specification plugging criteria.

Plugging Plans SG A: 730 total tubes plugged at end of 1D28.

666 tubes plugged prior to 1D28 139 tubes returned-to-service (RTS) from de-plugging activities (23 tubes RTS w/sleeves).

o Max volumetric/support wear of 36 percent TW (1 indication) in tubes returned-to-service.

203 tubes plugged (67 tubes w/ stabilizers) from 1D28 inspection results.

SG B: 437 total tubes plugged at end of 1D28.

493 tubes plugged prior to 1D28 136 tubes returned-to-service (RTS) from de-plugging activities (19 tubes RTS w/sleeves).

o Max volumetric/support wear of 36 percent TW (1 indication) in tubes returned-to-service.

80 tubes plugged (26 tubes w/ stabilizers) from 1D28 inspection results.

Sleeving Plans The sleeving strategy implemented at 1D28 uses "corrective" sleeves (CSV) and "preventative" sleeves (PSV). A CSV is installed at a location where a repairable flaw (i.e., volumetric indications 40 percent TW or crack-like indications) is identified with ECT at the support location. A PSV is a sleeve installed at support locations above a CSV through the fifth support (05H). See below tables for summary of sleeves installed in tubes that will remain in-service after 1D28.

SG A Sleeving Summary Tubes w/ Sleeves Sleeve Type 01H 02H 03H 04H 05H Total De-Plugged Tubes 23 Corrective 19 10 10 8

4 51 Preventative 0

12 13 15 9

49 1D28 Tubes 509 Corrective 249 180 65 87 30 611 Preventative 0

217 370 407 394 1388 Total 268 419 458 517 437 2099 SG B Sleeving Summary Tubes w/ Sleeves Sleeve Type 01H 02H 03H 04H 05H Total De-Plugged Tubes 19 Corrective 15 8

4 4

4 35 Preventative 0

11 15 15 15 56 1D28 Tubes 181 Corrective 110 57 17 19 6

209 Preventative 0

98 148 161 165 572 Total 125 174 184 199 190 872

7. Describe in-situ pressure test and tube pull plans and results (as applicable and if available).

Updated from ML24267A296 response.

SG A, 18 Indications in 17 tubes were tested. All indications passed with no tube failures or leakage.

SG A Indications In Situ Pressure Tested in 1D28 S/G Row Col Location A

32 115 SAI @ TSH+0.57 SCI @ TSH+0.42 A

31 58 SAI @ 05H+0.72 A

82 37 SAI @ 02H+0.88 A

15 122 SAI @ 01H+0.8 A

68 89 SAI @ 01H -0.77 A

70 91 SAI @ 01H -0.51 A

95 88 SAI @ 01H -0.53 A

21 124 SCI @ TSH -0.03 A

30 55 SCI @ TSH -0.14 A

92 119 SCI @ TSH -0.24 A

100 103 SCI @ TSH+0 A

103 98 SCI @ TSH+0.03 A

104 97 SCI @ TSH -0.06 A

107 100 SCI @ TSH -0.03 A

107 102 SCI @ TSH+0.09 A

109 102 SCI @ TSH -0.06 A

110 101 SCI @ TSH -0.09 SG B, 5 indications in 5 tubes were tested. All indications passed with no tube failures or leakage.

SG B Indications In Situ Pressure Tested in 1D28 S/G Row Col Location B

3 58 OBS @ DBC -9.94 B

30 51 SAI @ TSH+0.75 B

1 44 SAI @ DBH+0.64 B

24 115 SAI @ 01H+0.53 B

75 92 SAI @ 01H+0.19 OBS - Obstruction DBC - Diagonal Bar Cold Leg For the flaw in SG B R1-C44, please identify whether any wear or dent is present at the location and provide the structural depth and length for the flaw.

See table below. Note that this flaw had an axial length of 1.89" initially reported in the flaw report in September 2024 (12-9383369-000). The previously reported 1.89" erroneously included some of the structure width as part of the axial length measurement. It was later confirmed that the total length of 0.64" from the profiling is accurate and is the value that has been used.

Profile Information on SG B R1-C44 SAI @ DBH S/G Row Col Location Max Depth

(%TW)

Total Length (in)

Structural Equivalent Depth (%TW)

Structural Equivalent Length (in)

B 1

44 SAI @ DBH+0.64 67 0.64 61.6 0.59 Notes:

1. Depth and Lengths are from the depth profiling per ETSS I28432.

2. There are no wear or dent signals associated with this indication or location.

8. Discuss the following regarding loose parts:

a. The inspections performed to detect loose parts.

b. A description of any loose parts detected and their location within the SG (including the source or nature of the loose part, if known).

c. If the loose parts were removed from the SG.

d. Indications of tube damage associated with the loose parts.

Updated from ML24267A296 response.

The hot leg top of tube sheet (TTS) region was inspected with +Point up to a nominal 4 inches, but not less than 3.5 inches and not less than the height of the sludge pile, above TTS. A similar inspection was performed for the cold leg TTS region 3 tubes deep along the periphery and tube lane and 3 inches above the TTS. Foreign object search and retrieval (FOSAR) was performed for the periphery, tube lane annulus, and stay cavity areas. This is similar to the last outage.

The following tables summarize the loose parts identified during the 1D28 inspections and tubes with degradation associated with loose parts. All objects remaining in the SG have either been evaluated to remain in the SG or have had affected tubes plugged.

SG A Loose Part Table FOTS ID Location Description Remaining in SG 106 TSC +0.00 Metallic Like Object. Same as #495 Yes 108 TSH +0.00 Wire No 111 TSH +0.00 Flex/Flat Metal. See #540/#543 Yes 112 TSH +0.00 Metallic (maybe flex)

Yes 153 TSH +0.39 Flat Metal Object Yes 190 TSH +0.00 Metal Object No 331 TSH +1.19 Flat Metallic Object Yes 467 TSH +0.00 Flat Yes 468 TSH +0.00 Small Wire No 469 TSH +0.00 Small Reflective Object Yes 471 TSH +0.00 Small Diameter Wire No 472 TSH +0.00 Bristles No 473 TSH +1.00 Small Diameter Wire No 475 TSH +0.00 Metallic Piece No 477 TSC +0.00 Bristle Yes 478 TSC +0.00 Bristle No 480 TSC +0.00 Metallic Flake No 481 TSC +0.00 Flex Gasket No 487 TSC +0.00 Flex No 488 TSH +0.00 Bristle Yes 491 TSH +0.00 Metal Object Yes 495 TSC +0.00 Small diameter wire No 517 TSH +1.03 Metallic Object Yes 540 TSH +0.00 Wire No 543 TSH +0.00 Metallic Object. See #111 / #540 Yes 547 TSH +0.13 Object Yes SG B Loose Part Table FOTS ID Location Description Remaining in the SG 48 TSC+0.00 Metal Object Yes 49 TSH +0.00 Metallic object Yes 51 TSH +0.00 Metal Object Yes 79 TSC+0.00 Metal Object Yes 130 TSH +0.20 Object Yes 133 TSH+0.00 Rock Yes 223 TSH+0.25 Flat Object Yes 225 TSH+0.50 Flex Yes 226 TSC+0.00 Flex Yes 227 TSC+0.00 Bristle Yes 229 NTL Wire/ Flex Fixed to TTS at NTL Yes 231 TSH+1.00 Wire Yes 232 TSH+0.00 Small Diameter Wire No 234 TSC+0.00 Bristle Bundle No 249 TSH +0.25 Wire No 265 TSC+0.00 Wire No NTL - No Tube Lane Tube with Degradation Associated with Loose Parts (SVI/VOL Indications)

SG Row Col Elev Offset Ind Maximum Depth

(%TW)

A 114 125 TSH 0.12 SVI 28 A

117 58 VS7 4.76 SVI 38 A

134 93 TSH 0.08 SVI 40 A

126 105 TSH 0.29 SVI 46 A

52 59 TSH 0.21 VOL 25 A

133 64 TSH 0.08 VOL 36 A

33 138 02H

-6.48 VOL 25 A

104 127 TSH 0.56 VOL 15 A

104 121 TSH 0.53 VOL 14 A

35 138 02H

-3.2 VOL 31 A

96 33 TSH 0.24 VOL 31 A

131 64 TSH 0.24 VOL 33 A

118 125 TSH 0.16 VOL 16 A

132 93 TSH 0.03 VOL 35 A

92 29 TSH 0.24 VOL 20 A

33 138 02H

-10.35 VOL 26 B

127 62 TSH 0.19 SVI 49 B

129 62 TSH 0

SVI 34 B

55 82 TSH 4.91 VOL 16 B

137 92 TSH 10.45 VOL 25 B

115 74 06H

-0.75 VOL 22 B

137 92 TSH 12 VOL 24 SVI - Single Volumetric Indication VOL - Volumetric

9. Discuss the scope and results of any secondary side inspection and maintenance activities (e.g., in-bundle visual inspections, feedring inspections, sludge lancing, assessing deposit loading, etc).

Updated from ML24267A296 response.

Sludge lancing was performed in both Steam Generators. The Steam Generators were lanced for an extended period of time (greater than 80 hrs each).

Post-lancing In-bundle visual inspections were performed on the TTS area. Tubesheet inspections identified sludge deposits in localized regions.

The following areas were inspected in both Steam Drums:

1. Dryer deck surface

2. Moisture separator can deck and hatch

3. Selected steam separator cans

4. Dryer deck area

5. Steam deflector

6. Steam outlet nozzle

7. Feedring

8. U-bend top of bundle area In SG A the following items were reported: Foreign material, loose separator can, loose dryer hardware, and excessive sludge loading.

In SG B the following items were reported: loose dryer hardware, foreign material, and excessive sludge loading.

Deposit mapping and deposit loading for both steam generators was also performed based on eddy current data from 1D28.

10. Discuss any unexpected or unusual results. Review the number of indications for 1R27 and 1D28 since 1R27 seemed off.

Updated from ML24267A296 response.

For both SGs, the quantity of crack like indications far exceeded estimates based on previous operating history as shown in Question 5 above. For comparison, in 1R27 the total number of crack like indications (any location) for both SGs was 56 and in 1D28 there were 1427.

11. Provide the schedule for steam generator-related activities during the remainder of the current outage [i.e., activities during the remainder of the current shutdown period].

Updated from ML24267A296 response.

SG Primary Activities Remaining Remove Nozzle Dams 8/28 (To be determined (TBD) based on Primary Coolant System drain down)

Install Primary Manways 8/29 SG Secondary Activities Remaining Install Secondary Manways 8/14 (TBD based on secondary drain down)

SG 3 inch Handhole Installation Start SG A 8/18 (TBD based on Sec Side drain down)

Final PT and surface finish inspection SG A 8/27 (TBD based on Sec Side drain down)

Start SG B 8/28 (TBD based on Sec Side drain down)

PT and surface finish inspection SG B 9/6 (TBD based on Sec Side drain down)

SG Chemical Cleaning Inject in SG A 9/15 Cleaning complete in SG A 9/22 Inject in SG B 9/23 Cleaning complete in SG B 10/1 SG Sludge Lancing Starts after 1st SG is cleaned, lasts 10 days Provide the number of 3 inch handholes being added Two handholes in each SG.

12. Discuss any actions taken or plans for obtaining water samples or deposit samples (e.g.,

sludge pile, tube scale, etc.) to evaluate potential detrimental chemistry conditions or contaminants (e.g., chlorides, sulfates, Pb) during the plant shutdown.

Updated from ML24267A296 response.

Deposit samples were taken from both SGs at the 1D28 inspections and characterized for chemical constituents and physical morphology.

ML25309A014 NRC-001 OFFICE NRR/DORL/LPL3/PM NRR/DORL/LPL3/LA NRR/DNRL/NCSG/BC NAME JPoole SLent SBloom DATE 10/24/2025 11/05/2025 09/08/2025 OFFICE NRR/DORL/LPL3/BC (A)

NRR/DORL/LPL3/PM NAME IBerrios JPoole DATE 11/05/2025 11/06/2025