L-2025-101, NextEra Energy, Seabrook OR23 Steam Generator Tube Inspection Report
| ML25125A317 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 05/05/2025 |
| From: | Mack K NextEra Energy Seabrook |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| L-2025-101 | |
| Download: ML25125A317 (1) | |
Text
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ENERGY8 SEABROOK U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555-0001 Re:
Seabrook Station Docket No. 50-443 Renewed Facility Operating License NPF-86 Seabrook OR23 Steam Generator Tube Inspection Report May 5, 2025 L-2025-101 10 CFR 50.36 NextEra Energy hereby submits the enclosed Seabrook Station Cycle 23 Refueling Outage (OR23) Steam Generator Tube Inspection Report. In accordance with Seabrook Station Technical Specification (TS) 6.8.1.7, the report is required within 180 days after the initial entry into MODE 4 following completion of the Steam Generator tube inspection required by Seabrook Station TS 6.7.6.k.
The enclosed report addresses the requirements of TS 6.8.1.7, except for the analysis of stress corrosion cracking mechanisms aspect required by subsection "d". This analysis will be provided after addressing recommendations from an independent third-party review of the Operational Assessment.
The remaining information in sub-section "d" of TS 6.8.1. 7 will be submitted no later than 30 days from the date of this letter.
This letter contains no new regulatory commitments.
Should you have any questions regarding this submission, please contact Maribel Valdez, Fleet Licensing Manager, at 561-904-5164.
I declare under penalty of perjury that the foregoing is true and correct.
Executed on May 5, 2025.
Sincerely, Kenneth A. Mack Director, Licensing and Regulatory Compliance cc:
USNRC Regional Administrator, Region I USNRC Project Manager, Seabrook Station Nuclear Plant USNRC Senior Resident Inspector, Seabrook Station Nuclear Plant NextEra Energy Seabrook, LLC P.O. Box 300, Lafayette Road, NH 03874 to L-2025-101 Steam Generator Tube Inspection (24 Pages Follows)
Seabrook Station Docket No. 50-443 Enclosure L-2025-101 Page 1 of 24 Seabrook Station OR23 Steam Generator Tube Inspection Report Design and Operating Parameters:
Seabrook Station is a Westinghouse 4-loop PWR with Model F steam generators (SGs). The SGs are U-tube heat exchangers with tube bundles fabricated using thermally treated Alloy 600 tubing.
Each SG contains 5,626 tubes arranged in 59 rows and 122 columns. The tubes have a square pitch arrangement, and nominal tube OD is 0.688" with a 0.040" nominal wall thickness. Internal supports include 8 horizontal tube support structures made of stainless steel where the lowest is a flow distribution baffle (FOB) with drilled holes. The other 7 structures are broached-hole, quatrefoil tube support plates (TSPs). There are no inspection ports installed at the uppermost TSPs. The U-bend region is supported by 3 sets of anti-vibration bars (AVBs). Rows 1-10 of tubing in each SG were stress relieved in the U-bend region after bending. A schematic of a typical Model F SG is shown in Attachment 2 of Report in ADAMS Accession No. ML102980089.
The Steam Generator Tube Inspection Report for Seabrook Station is submitted for the inspection of the SGs during refueling outage 23 (hereafter referred to as the OR23 inspection or outage) per Technical Specification (TS) 6.8.1.7. The OR23 SG inspection was performed in accordance with TS 6.7.6.k. The Seabrook SG Program has no deviations from NEI 03-08 Mandatory or Needed (shall) requirements of the EPRI SGMP Guidelines referenced by NEI 97-06 Rev 3. At unit shutdown for the OR23 inspection, the SGs had operated for approx. 30.1 EFPY since installation. This included operation for approximately 2.78 EFPY during the 2 fuel cycles since the previous SG inspection in OR21. Nominal Thot during full-power operation is 621 deg F. Initial entry into Mode 4 following completion of the OR23 inspection was made on November 6, 2024. Acronyms used in this report are tabulated in Appendix A.
A. Scope of Inspections Performed on each SG The OR23 inspection scope was selected to meet the requirements of the Seabrook Station Technical Specifications, the SG Program Guidelines (NEI 97-06 Rev 3) and its referenced EPRI SGMP Guidelines. Unless otherwise noted, the OR23 SG base scope inspection in each SG is outlined below:
Primary side:
- 100% full-length enhanced probe exams. All active tubes inspected with array/bobbin probes.
- 100% inspection of Ding/Dent indications.
ONG/ONT.::: 5 Volts examined with the +Point' probe.
DNG/DNT < 5 Volts screened with the bobbin coil.
- 100% +Point' probe inspection of all tubes with potentially high residual stress.
At HL and CL TSP locations Within the tubesheet
- Various diagnostic/special interest exams using the +Point' probe including all I-codes from bobbin and array probe exams, and any tubes with unusually high growth.
- Visual inspection of all mechanical and welded plugs.
- Visual inspection of all channel head bowl components, and bowl scan everywhere within the channel head bowl with a remote visual camera in both the HL and CL per
Seabrook Station Docket No. 50-443 Enclosure L-2025-101 Page 2 of 24 Westinghouse NSAL 12-1 Rev 1, "Steam Generator Channel Head Degradation," October 2017.
Secondary side:
- Upper bundle flush (UBF) of tube sections in the U-bend regions and uppermost TSPs.
- Sludge lancing at the TTS and the baffle plate (FOB).
- Cleanliness inspection of the TTS (annulus, no-tube lane) and FOB after sludge lancing.
- Foreign object search and recovery (FOSAR) at the TTS including several in-bundle exams on the HL and CL.
- Visual inspection of components of the Upper Internals including the feedwater ring and supports, and moisture separator components.
B. NDE techniques utilized for tubes with increased degradation susceptibility Seabrook's tube sub-populations with increased degradation susceptibility include ones with the presence of ding/dent indications, and tubes with potentially high residual stress. There are a total of 67 high stress tubes (15 in SG-A, 26 in SG-B, 18 in SG-C and 8 in SG-D). Portions of tubing which are a few inches above the TTS, in the peripheral section of the bundle are also susceptible to wear due to foreign objects because of the relatively high velocity of the secondary-side fluid in this region. The NOE techniques utilized for tubes with increased degradation susceptibility are summarized in the Table below:
Susceptible population NOE Techniques used High stress tubes
+Point', Array probes Dings, Dents;::: 5 Volts
+Point', Array probes Peripheral tubes, Bulges/Over-expansions Array probe C. For each degradation mechanism found:
The following degradation mechanisms were identified during the OR23 inspection:
- Wear at tube support structures: AVB wear, broached TSP wear
- Wear (volumetric) indications at or above the TTS and at TSPs Caused by use of legacy sludge lance equipment Wear (VOL) indications due to interaction with FOs at the TTS, TSPs and the freespan
- Axial ODSCC at the tubesheet expansion transition (EXT) region
- Circumferential ODSCC at a DNG/DNT: a potentially new degradation mechanism reported on a tube was conservatively classified as stated and assigned an SCI reporting code.
Seabrook Station Docket No. 50-443 Enclosure L-2025-101 Page 3 of 24
- 1. The non-destructive examination (NOE) techniques utilized Table 1 a shows the list of the NOE techniques utilized for detection in OR23.
Table 1 a - NDE Techniques utilized for Detection Degradation Location Detection Detection ETSS Applicability Mechanism probe AVB 1-96041.1 R8 AVB locations AVB,TSP Bobbin 96004.3 R14 AVB, TSP locations TSP 1-96043.4 R1 tapered/flat wear Wear at tube FDB 1-96042.1 R4 drilled supports support TSP 1-11956.3 R3 (axial)
FDB wear, LPW with part structures Array 1-11956.4 R3 (circ) present AVB 1-17909.1 R1 (axial)
AVB wear detection l-17909.4R1 (circ)
AVB
+Point' 1-10908.5 RO freespan TSP 96910.1 R12 broached TSPs Bobbin 27091.2 R2 PLP wear (part not present) freespan Array 17901.1 thru 17906.1 RO morphology dependent; part 17901.3 thru 17906.3 RO not present FO wear
- freespan, 27901.1 R1, 27902.1 R2, PLP/LPW wear; morphology TSP, EXT +Point' 27903.1 R1, 27904.1 R2, dependent; part not present; LPWwear 27905.1 R2, 27906.1 R1, legacy wear from SL 27907.1 R2 equipment 21998.1 R4 Volumetric; legacy wear from Wear (VOL) freespan
+Point' sludqe lance equipment tapered wear; legacy wear 27906.3 R1 from sludqe lance equipment FDB 1-28411 R4 drilled TSP freespan 1-28412 RS straiqhts only
- freespan, Bobbin 1-28413 RS straight leg only; sludge pile; TTS,TSP TSPs (non-DNT, DNT:s;2V)
TSPs 10013.1 R1 TSP/FDB w/ DNT::; 5V freespan 24013.1 R2 includinq DNG::; 5V freespan 20403.1 RS w/o deposits
- TTS, 20400.1 RS TTS EXT, freespan freespan Axial support Array extended to ODSCC structures 20402.1 RS TSP w/ DNTs ::; 5V U-bends 10413.2 RO low rows U-bends 10411.1 RO, 10411.2 RO All rows TSP,FDB 22401.1 R4 dented supports
- supports, Support structures, freespan,
- freespan, 21409.1 R7 TTS
+Point' sludge pile, TS crevice TTS 1-28424 R4 sludqe pile, OXP/ETL
Circ.
TTS EXT Array 20400.1 RS EXT, sludge pile, TTS ODSCC region
+Point' 21410.1 R6 expansion anomalies
Seabrook Station Docket No. 50-443 Enclosure L-2025-101 Page 4 of 24 Table 1 b shows the list of the NOE techniques utilized for sizing in OR23.
Table 1 b - NDE Techniques utilized for Sizing Sizing probe Sizing ETSS Degradation Mechanism Location / Applicability Bobbin 1-96041.1 RS AVB Wear AVB contact points 96910.1 R12 TSP Wear Broached TSP locations 21998.1 R4 Foreign object wear 27901.1 R1 Wear (VOL)
Wear due to legacy sludge lance 27906.3 R1 27905.1 R2 (maintenance) equipment
+Point' Broached TSP locations (08H);
1-28432 R2 Axial ODSCC w/ and w/o DNTs 1-28431 R3 At HL TTS Expansion Transition 21410.1 R6 Circumferential ODSCC At dented broached TSP at a DNT/DNG
- 2. Location, orientation (if linear), measured size (if available), and voltage response for each indication Thirty-seven (37) new indications of AVB wear were reported in OR23; the largest new AVB wear indication was 27% TW. Bobbin probe ETSS 96041.1, used for detection of AVB wear, is site-validated for depth-sizing as well. To get more consistent sizing results from one inspection to the next, a fixed sizing curve was developed and used in OR23 to perform AVB wear (bobbin) measurements. Use of this technique reduces the potential to get large errors when different calibration standards are used between outages. To facilitate used of this method, flaws from the prior inspection (OR21) were resized to get a more realistic depth comparison between the previous and current AVB wear indication depths. Resizing resulted in a slight decrease in percentage TW depth for AVB wear sized in OR21 such that, some smaller indications fell below the reporting threshold and were not reported in OR23. The location, orientation, measured size and voltage response for OR23 AVB wear indications are listed in Appendix C-1.
Volumetric wear indications reported in OR23 are attributed to the use of legacy sludge lancing equipment, wear at broached TSPs or wear associated with foreign objects (FOs). Indications reported in row 1 that are located approximately 18" above the tubesheet or above the FOB plate are attributed to the interaction of historical sludge lancing equipment with the tubes. Prior and current volumetric indications were reclassified by the OR23 inspection vendor. Volumetric wear that was not coincident with a tube support structure was given the indication code VOL. Both the Bobbin and Array probes were used for detecting this mechanism. Based on analyst judgement, different +Point' ETSSs were used to size VOL indications based on the shape of the wear scar. Volumetric wear indications in the following areas are considered to originate from foreign objects: ones that are at the edge of TSP intersections which are not aligned axially with the land contact point, that reside slightly above or below the TSP, and ones in proximity to the TTS. Nine (9) VOL indications (App. C-3) were newly reported in OR23 (1 in SG-A, 2 in SG-B, 2 in SG-C and 4 in SG-D). The 4 indications in SG-D were associated with a PLP in the vicinity of the tubes and were plugged and stabilized in OR23. No other VOL indications were associated with PLPs. VOL indications located just outside the TSP edges but with no PLP signal are likely caused by transient FOs. The indication in SG-A is likely from legacy sludge lance equipment
Seabrook Station Docket No. 50-443 Enclosure L-2025-101 Page 5 of 24 based on its location and elevation. The reclassification of VOL reduced the population of indications previously tracked as broached TSP wear. No new broached TSP wear indications were reported, and no volumetric wear was reported at the FDBs.
For the wear degradation mechanisms found in OR23, the location, orientation, measured size and voltage response of broached TSP wear and volumetric (VOL) wear are listed in Appendix C-2 and C-3, respectively. The broached TSP and VOL indications were all sized using qualified EPRI ETSSs (Table 1 b) for the +Point' probe and are included in Appendix C-2 and C-3. The total number of wear indications (at tube support structures) that are less than 20%TW is summarized below:
Table 2a - No. of Indications <20% TW (at tube support structures)
Degradation Mechanism SG-A SG-B SG-C SG-D Reference AVBWear 260 220 165 311 App. C-1 TSP Wear (broached) 4 0
1 2
App. C-2 Volumetric (VOL) Wear*
5 2
2 1
App. C-3
- Indication counts shown are for ones within % inch off the edge of a tube support structure but are not part of the broached TSP wear population (App. C-2).
Nine (9) crack-like ODSCC indications were reported during the OR23 SG inspection; none were on "high stress tubes":
Two (2) were single axial indications (SAls) located in the sludge-pile at the HL expansion transition (EXT) region.
The remaining flaws were all located at the uppermost TSP in SG-B, and were classified as SAls except one which was recorded as a single circumferential indication (SCI). Most indications were coincident with dents at the upper or lower edge of the TSP, and all except one was in the HL.
One crack-like flaw indication in R4C119 of SG-B was detected during the full-length array exam and was influenced by an overlapping ONG signal that was traceable to OR03. Because of the interaction between the ONG and the new indication, the ECT signal was complex, making it difficult to characterize the flaw. The indication showed attributes of both volumetric wear and circumferential cracking. Diagnostic exams were performed with the +Point' as well as the Ghent probe. The most conservative approach was taken to classify the indication as a single circumferential indication (SCI) at a DNT/DNG. There is no known history of an SCI at a DNT/DNG in Alloy 600TT SG tubing; therefore, this is potentially a new degradation mechanism.
The location, orientation, measured size and voltage response of all 9 crack-like ODSCC indications are summarized in the Table 2b below:
Table 2b - Location, orientation, measured size and voltage of ODSCC Indications Location Reporting Code Measured sizes Max. Volt~
lndic. SG RoVI Col Elevation Bobbin Array +Point' lenqth max. depth (+Point')
1 A
22 61 TSH-0.19 NDO RRC SAi 0.16 in. 84.3%TW 1.48 2
B 11 3
OSH-0.51 NOD SAi SAi 0.22 in. 60.3%TW 0.38 3
B 12 120 OSH-0.33 DNT NOD SAi 0.14 in. 50.8%TW 0.27 4
08H+0.50 DNT NDO SAi 0.16 in. 58.2%TW 0.24
Seabrook Station Docket No. 50-443 lndic. SG 5
B 6
B 7
B 8
B 9
C Ro\\i\\.
17 40 53 4
28 Location Col Elevation 119 08H+0.48 104 08H+0.43 40 08H+0.35 119 08C-0.53 57 TSH-0.27 Enclosure Reporting Code Bobbin Arrav +Point' DNT NDD SAi DNT NDD SAi NDD SVI SAi DNG/DNT SCI SCI NDD SAi SAi L-2025-101 Page 6 of 24 Measured sizes Max. Volts lenqth max. depth (+Point
0.13 in. 61.3%TW 0.40 0.21 in. 57.4%TW 0.17 0.24 in. 58.2%TW 0.33 0.21 in.
97%TW 0.64 0.19 in. 93.0%TW 2.52
- Indication was sized with ETSS 21410.1 at 4.125% NOE PDA and crack angle of 23 deg or 20.9% of dent extent.
The indications at R12C120, R17C119 and R40C104 showed precursor signals in the OR21 data. A precursor signal was in the indication in R 11 C3 but only from the X-probe. Precursor signals were also present in R53C40, but RPC data was not available. No signal was detectable from the indication in R4C119.
- 3. 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 Wear Indications:
The maximum observed wear indication at tube support structures was 41 % and 20%
for AVB and broached TSP wear, respectively. For AVB wear, all indications were less than the CM structural limit using EPRI ETSS 96041.1 (for a bounding 1" axial length).
Similarly, for broached TSP wear, all indications were significantly less than the condition monitoring (CM) structural limit using EPRI ETSS 96910.1. Therefore, CM for both leakage and structural integrity was satisfied at OR23 for AVB and broached TSP wear indications. The maximum observed volumetric (VOL) wear indications, 39% TW in SG-D and 38% in SG-8, were less than the CM limits using EPRI ETSSs 27901.1 and 96041.1, respectively, when all uncertainties are considered. Therefore, the volumetric indications met the performance requirements for condition monitoring.
The OR23 inspection results also validate the projections of the previous inspection at OR21 for all wear degradation mechanisms. The margin to the tube integrity performance criteria and comparison with the margin predicted to exist at OR23 by the previous forward-looking tube integrity assessment are summarized in the Table below for the wear degradation mechanisms found.
Degradation Mechanism Max depth at CM limit OR23 %T TSP wear (broached) 20 45.0 59.0 Volumetric (VOL) wear 38/39 N/A Note1 45.9 Note2 Note 1: OR21 OA for FO wear not projected to challenge tube integrity at OR23.
Note 2: Value shown is the CM limit with the lower margin to the maximum observed VOL indication (38%).
Seabrook Station Docket No. 50-443 ODSCC Indications:
Enclosure L-2025-101 Page 7 of 24 Axial ODSCC indications at TSPs (Items 2 to 7 in Table 2b) were assessed regarding the need for in-situ testing. For each indication, the lowest predicted 95/50 burst pressure exceeded the 3xNOPD value of 3860 psid for Seabrook. All indications satisfied CM for structural integrity analytically as shown on the pop-through Chart in Figure 1 of Appendix B. Individual flaw profile plots of NOE length/depth and calculated structural equivalent length/depth, and relevant tube integrity parameters are also shown in Figure 3 of Appendix B. Thus, the structural integrity criteria (SIPC) are satisfied for axial ODSCC indications at TSPs. In the CM assessment for leakage integrity, all axial ODSCC indications at TSPs plotted below the pop-through curve and therefore met the CM criteria for accident leakage by analysis as shown in Figure 2 of Appendix B.
Axial ODSCC indications at the TS expansion transition (Items 1, 9 in Table 2b) were assessed during CM. For the indication in tube R22C61 of SG-A (Item 1 ), the lowest predicted 95/50 burst pressure (6323 psi) exceeded the 3xNOPD value of 3860 psid for Seabrook. Therefore, the indication satisfied CM analytically for structural integrity and SIPC are satisfied. For leakage integrity, the indication's +Point' voltage (1.48V) was below the voltage criterion, Vcrit of 2.4V in the SGMP In-Situ Pressure Test Guidelines.
Therefore, the maximum depth threshold for leakage testing (MDrHR-L) is satisfied, since the depth of the flaw that exceeds the calculated MDrHR-L of 79.2% is less than 0.1 inch.
Thus, the indication in tube R22C61 of SG-A met the CM structural and leakage integrity criteria in OR23. Flaw profile plots of NOE length/depth and calculated structural equivalent length/depth, and relevant tube integrity parameters are also illustrated in Figure 4 of Appendix B for the 2 axial ODSCC indications at the TS expansion transition.
The indication in tube R28C57 of SG-C (Item 9) exceeded the allowable depth limit for CM at its structural equivalent length (SEL) and therefore, did not analytically meet the structural integrity criteria. SEO was 81.1 % TW as compared to a CM limit of 77.4% TW at the SEL. For leakage integrity, the indication's +Point' voltage (2.52V) was more than the voltage criterion, Vcrit of 2.4V. Based on the results of CM screening, tube R28C57 in SG-C was selected for in-situ pressure testing (ISPT) to demonstrate CM for structural and leakage integrity. ISPT was conducted at simulated conditions for NOPD, MSL break and 3 times NOPD conditions, as required by the SGMP In-Situ Pressure Test Guidelines. A maximum leakage rate of 0.0476 gpm (68.5 gpd) occurred at MSLB conditions during the ISPT. Since the accident induced leakage performance criteria (AILPC) of 500 gpd per SG (TS 6.7.6.k), less the low-level (approx. 1 gpd) primary-to-secondary operational leakage during normal operation, was more than the maximum leakage rate during ISPT (68.5 gpd), the TS condition monitoring criteria was met at OR23 for this indication. At all simulated conditions during ISPT, the tube did not burst; therefore, the structural integrity performance criteria (SIPC) was met.
Circ ODSCC at a DNT/DNG: Since there is no qualified technique that is specific to this mechanism, EPRI ETSS 21410.1 for circumferential ODSCC was site-qualified for percent degraded area (PDA) sizing of circumferential indications and was used to evaluate the indication for structural integrity. Since the indication was at the bottom edge of the TSP, in the assessment for structural integrity, consideration was given to the influence of secondary loading per guidance in Section 3 of the SGMP Integrity Assessment Guidelines. The need to incorporate secondary loads was exempted based on the assessment.
Seabrook Station Docket No. 50-443 Enclosure L-2025-101 Page 8 of 24 A CM limit curve for structural integrity was plotted for ETSS 21410.1 using NOE percent degraded area (PDA) as the structural variable. With the NOE PDA of the flaw (4.125%)
plotted on the burst pressure line, the indication fell well below the limiting PDA value of 20.9% as shown in Figure 5 of Appendix B. The indication therefore analytically met the CM requirements for structural integrity. In addition, based on the crack angle (23 degrees) being less than 180 degrees, CM and structural integrity are met per the proof test screening in the SGMP ln-Siti Pressure Test (ISPT) Guidelines. No industry/EPRI guidance exist for accident-induced leakage screening of circumferential ODSCC at a ONT/ONG. Lacking an analytical acceptance criterion, the flaw was selected for ISPT to demonstrate that it met the leakage criteria. During ISPT, the tube did not leak or burst when tested at hold points to simulate NOPD, MSLB and 3xNOPD conditions.
demonstrating structural integrity. Therefore, CM structural integrity was satisfied for this flaw using multiple approaches.
- 4. The number of tubes plugged during the inspection outage Seventeen (17) tubes were plugged based on the OR23 inspection. Tubes plugged for each degradation mechanism are summarized below in Table 3:
Table 3 - OR23 Tubes Plugged SG Tube Deqradation Mechanism Location Notes A
R22 C61 Axial ODSCC (SAi) at TSH-0.19" In the sludge pile region.
expansion transition B
R4 C119 Circumferential OOSCC 08C-0.53" Potentially new degradation (SCI) at a ONT/ONG mechanism. ISPT used to show leakaqe integrity. Tube stabilized.
B R11 C3 Axial ODSCC (SAi) at TSP 08H-0.51" No ONT at location.
B R12 C120 Axial ODSCC (SAls) at 08H+0.50" Two SAls at TSP.
TSP 08H -0.33" DNTs at location.
B R17C119 Axial ODSCC (SAi) at TSP 08H+0.48" ONT at location.
B R40 C104 Axial ODSCC (SAi) at TSP 08H+0.43" ONT at location.
B R53 C40 Axial ODSCC (SAi) at TSP 08H+0.45" No ONT at location.
B R58 C63 Volumetric (VOL) wear 07H+1.76" New volumetric wear (38%) in the freespan. No PLP signal.
Preventively plugged to add margin to the OA.
C R28 C57 Axial ODSCC (SAi) at TSH-0.27" In the sludge pile region.
expansion transition ISPT required to meet CM criteria for structural, leakage integrity.
Tube stabilized.
D R40 C66 AVB wear AV2-0.24" 41 % TW; plugging required by Tech Specs.
D R20 C28 Volumetric (VOL) wear 03C+1.01" PLP indication coincident with wear (17%TW). Preventively pluqqed, stabilized.
D R20 C29 Volumetric (VOL) wear 03C+0.51" PLP indication coincident with wear (22% TW). Preventively plugged, stabilized.
Seabrook Station Docket No. 50-443 Enclosure L-2025-101 Page 9 of 24 SG Tube Degradation Mechanism Location Notes D
R21 C28 Volumetric (VOL) Wear 03C+0.75" 13% TW. Adjacent to tubes with PLP indication with wear.
Preventively plu\\::med, stabilized.
D R56 C57 Volumetric (VOL) Wear 01H+0.48" New volumetric wear (39%)
coincident with PLP. Preventively pluqged, stabilized.
D R56 C56 Preventive pluaoing 01H+0.05" No wear. PLP signal at location in D
R57 C56 Preventive pluaaing 01H+0.28" proximity to tube R56C57 with D
R57 C57 Preventive pluaaing 01H+0.19" PLP wear. Tubes stabilized.
No other tubes were plugged in OR23 for the remaining degradation mechanisms found.
D. 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 Wear Mechanisms:
In determining the tube integrity conditions predicted to exist at the next scheduled inspection (OR25), the forward-looking tube integrity assessment used a deterministic approach (per the SGMP Integrity Assessment Guidelines) to evaluate wear at tube support structures (AVBs, TSPs). The 2-cycle operating interval is assumed in analyses. For AVB wear, the highest growth rate (2.52% TW/EFPY) of any AVB wear identified in OR23 was applied to the deepest indication returned to service after OR23, even though the highest upper 95th growth rate (of all SGs) was 1.06%TW/EFPY. Similarly, for broached TSP wear, the highest growth rate (1.08% TW/EFPY) of any TSP wear identified in OR23 was applied to the deepest indication returned to service after OR23. Conservative growth rate projections of the AVB and TSP wear show that all structural and leakage criteria will continue to be satisfied until at least OR25. For the wear degradation mechanisms, the tube integrity conditions predicted to exist at the next scheduled SG inspection (OR25) relative to the applicable performance criteria are summarized in the Table below for each degradation mechanism. In all cases, the structural and leakage criteria are projected to be met at OR23.
Degradation Mechanism OR23 max depth Max proj'd depth EOC structural returned to svc (% TW) at OR25 (% TW) limit(%TW)
AVB wear 37 54.8 65.6 TSP wear (broached) 20 37.8 64.8 Volumetric (VOL) wear 37 Note 1 60.0 Note2 Note 1: No continuing degradation expected from legacy sludge lance equipment or from FO wear with the part no longer present.
Note 2: For FO wear at 1.5" length.
Stress Corrosion Cracking (SCC) Mechanisms: [This section to be provided in a subsequent submittal.]
Seabrook Station Docket No. 50-443 Enclosure L-2025-101 Page 10 of 24 E. The number and percentage of tubes plugged to date, and the effective plugging percentage in each SG The number and percentage of SG tubes plugged to-date, and the effective plugging percentage in each SG are summarized in Table 4.
Table 4 - Tubes plugged to-date and effective plugging percentage SG-A SG-8 SG-C Tubes Plugged 44 47 67 Percent Plugged 0.78%
0.84%
1.19%
F. The results of any SG secondary side inspections Secondary-Side Inspection (SSI) & Maintenance:
SG-D Total 73 231 1.30%
1.03%
Upper-Bundle Flush, Sludge lancing and FOSAR was performed in all four SGs. A total of approximately 166 lbs. of sludge was removed from the 4 SGs after completion of upper-bundle flush and sludge lancing in OR23. There was evidence of some hard sludge/scale during TTS in-bundle exams of the sludge pile region.
Twelve (12) foreign objects (metallic in nature) were identified during FOSAR activities at the TTS. Ten (10) of the objects appeared to be flex gasket material, and all ten were removed. The other two (2) metallic objects were legacy items and were not removed: a dumbbell-shaped object in SG-C, present since OR1, and a hollow metal fitting identified in OR19 in SG-D. The remaining objects were small pieces of tube scale and sludge rocks which are not potentially damaging to the tubes and therefore no retrieval attempts were made. A foreign object evaluation was completed for all objects found during FOSAR which were not retrieved (sludge, scale, and two (2) metallic legacy items). No tube damage was observed in any SG during FOSAR activities.
Upper Internals Inspection: Visual inspections were performed in all four SGs for looking for any erosion/corrosion, mechanical damage, foreign material, or unusual conditions. The visual inspection included the dryers, primary moisture separators, swirl vanes, feedring and J-nozzles. Pre-and post-bundle flush (UBF) visual exams of peripheral tubes, AVBs and sections of the uppermost TSPs were also completed.
Some moderate buildup of debris and tube scale was noted on some of the tubes. The broached openings of the TSPs were relatively clear and unobstructed after UBF.
During the upper internals inspection in SG-B, a band of discoloration on the wall of the steam drum, just above the feedring was observed. The discoloration was also reported during OR21, and no changes were noted between the OR21 and OR23 inspections. The discoloration appears to have been caused by a thin layer of magnetite that had spalled from the wall in this region; however, the base material appears to be intact. A minimal amount of erosion was observed inside some of the J-tubes (in all 4 SGs) at the interface with the feedring; the condition was typical as observed in prior outages. No loose parts, foreign objects, broken welds, or any other abnormal conditions were found during the USO exams.
Channelhead Components Visual Inspection:
Tube Plug Inspection: During the inspection of tube plugs in OR23, all installed plugs were confirmed to be in their correct location. In addition, all plugs were found to be
Seabrook Station Docket No. 50-443 Enclosure L-2025-101 Page 11 of 24 dry; no dripping plugs were identified. No degradation or visible signs of leakage were noted on the plugs during the visual inspection.
Other Channelhead Inspections: Visual inspection of various channelhead components were performed to identify degradation per guidance in Westinghouse NSAL 12-1 Rev 1, "Steam Generator Channel Head Degradation" and LR-ISG-2016-01, "Changes to Aging Management Guidance for Various Steam Generator Components." Areas inspected include the divider plate-to-channelhead weld, the weld at the top of the channelhead bowl drain tube, the channelhead-to-tubesheet girth weld seam region, the divider plate, and all cladded surfaces of the channel head bowl and tubesheet. The anomaly identified in the surface of the channel head cladding in the CL of SG-8 in OR20 1 was re-inspected in OR21 and OR23. There was noticeable change in this anomaly in OR23 from when it was first reported in OR20. The anomaly will be monitored in future remote visual inspections for noticeable changes. No other degradation was found during the visual inspection of channelhead components in OR23.
G. The primary to secondary leakage rate observed in each SG (if it is not practical to assign the leakage to an individual SG, the entire primary to secondary leakage should be conservatively assumed to be from one SG) during the cycle preceding the inspection which is the subject of the report Seabrook has tracked detectable normal operating leakage in SG-8 that has varied between 0.21 gpd and 1.1 gpd during the fuel cycles preceding the OR23 inspection. This low level of leakage has been detected for several cycles, fluctuating between O and 1.2 gpd. No normal operating leakage has been detected in SG-A, SG-C, or SG-D.
H. The calculated accident induced leakage rate from the portion of the tubes below 15.21 inches from the top of the tubesheet for the most limiting accident in the most limiting SG. In addition, if the calculated accident induced leakage rate from the most limiting accident is less than 2.49 times the maximum operational primary to secondary leakage rate, the report should describe how it was determined For application of H*, Seabrook committed that the component of operational leakage from the prior cycle from below the H* distance will be multiplied by a factor of 2.49 and added to the total accident leakage from any other source and compared to the allowable accident-induced leakage limit.
The assumed value for accident-induced leakage in the Seabrook UFSAR is 500 gpd
(=0.35 gpm) for the faulted SG and 940 gpd through the remaining three SGs, for a total leakage of 1440 gpd (=1.0 gpm). As stated in Section H, SG-8 experienced leakage in the range of 0.21 gpd to 1.1 gpd in the fuel cycles preceding the OR23 inspection. Since there is no observed operating leakage from the remaining SGs (SG-A, SG-C and SG-D), the predicted accident-induced leakage for each of these is zero. No leakage was detected from the SCC indications in SG-A, SG-8 or SG-C; this is supported by primary-to-secondary leak trends in SG-8 which show similar levels before and after OR23. Since there is no other degradation mechanism in SG-B that has been shown to be the source of the observed normal operating leakage, the entire observed operating leakage is assumed to come from the tubesheet expansion region. Conservatively assuming that the operating 1 Reference Section G6 of the OR20 SG Tube Inspection Report (NRC ADAMS Accession No. ML20295A551).
Seabrook Station Docket No. 50-443 Enclosure L-2025-101 Page 12 of 24 leakage in SG-B is at the upper end of the observed range (i.e. 1.1 gpd), the predicted accident-induced leakage (OosA) in SG-B is:
OosA = 2.49 x 1.1 gpd = 2.74 gpd (=0.0019 gpm)
Therefore, since the predicted accident-induced leakage from SG-B (2.74 gpd) is less than the assumed accident-induced leakage limit in the Seabrook UFSAR (500 gpd) for leakage through the faulted SG, and less than the total leakage limit for all SGs (1440 gpd), the accident-induced leakage performance criteria for Condition Monitoring are met.
I.
The results of monitoring for tube axial displacement (slippage). If slippage is discovered, the implications of the discovery and corrective action shall be provided A condition for licensing H* was to monitor for tube slippage within the tubesheet region.
Monitoring for slippage during the inspection was accomplished through the bobbin probe automated analysis process in accordance with guidance in Framatome Document: 51-9384059, "Automated Analysis". No tube slippage within the tubesheet was detected during the bobbin probe examinations.
Seabrook Station Docket No. 50-443 Enclosure L-2025-101 Page 13 of 24 APPENDIX A -Additional Information Abbreviations and Acronyms:
AILPC Accident-induced leak perf. crit.
ODSCC OD Stress Corrosion Cracking AVB Anti Vibration Bar OXP Over-expansion BLG Bulge PDA Percent degraded area CL Cold Leg Per Percent Through-Wall CM Condition Monitoring PLP Possible Loose Part DA Degradation Assessment POB Probability of Burst DBA Design Bases Accident POL Probability of Leakage DNG Ding PWSCC Primary Water SCC DNT Dent RRC Retest with rotating coil ECT Eddy Current Testing SAi Single Axial Indication EFPY Effective Full Power Years sec Stress Corrosion Cracking EOC End-Of-Cycle SCI Single Circumferential Indication EPRI Electric Power Research Institute SED Structural Equivalent Depth ETSS Exam Technique Spec Sheet SEL Structural Equivalent Length EXT Expansion Transition SG Steam Generator FDB Flow Distribution Baffle SGMP SG Management Program FO Foreign Object SIPC Structural Integrity Perf. Criteria FOSAR Foreign object search & retrieval SL Sludge lancing GPD (gpd)
Gallons per Day SSI Secondary-side inspection GPM (gpm) Gallons per Minute SVI Single Volumetric Indication HL Hot Leg TS Tubesheet ISPT In-situ pressure test TSC Tube Sheet Cold MNT Maintenance Related TSH Tube Sheet Hot MSLB Main steam line break TSP Tube Support Plate NDD No Degradation Detectable TTS Top of Tube Sheet NEI Nuclear Energy Institute TW Through Wall NOPD Normal operating pressure differential UBF Upper Bundle Flush NSAL Nuclear Safety Advisory Letter UFSAR Updated Final Safety Analysis Rpt OA Operational Assessment VOL Volumetric OD Outside Diameter
Seabrook Station Docket No. 50-443
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Enclosure APPENDIX B - Condition Monitoring Graphs for OR23 sec Indications 100 90 80 70 60 50 40 30 20 10 0
Figure 1 - CM Chart for Axial ODSCC Indications at TSPs Condition Monitoring for Axial ODSCC at Supports
+Point Probe, ETSS 1-28432
- CM Limit 1287DP L-2025-101 Page 14 of 24 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 Structural Equivalent Length (Inches)
Figure 2 - CM Leakage Chart for Axial ODSCC Indications at TSPs Condition Monitoring Screening for Accident Leakage for Axial ODSCC at Tube Support Plates 100 90 80 70
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60
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+Point Probe, ETSS 1-28432 POP THRU 0.25
- Pop Thru Limit 128432 Structural Equvalent Structural Equivalent Length (Inches) 0.50
Seabrook Station Docket No. 50-443 Enclosure L-2025-101 Page 15 of 24 APPENDIX B - Condition Monitoring Graphs for OR23 sec Indications Figure 3 - Profile Charts of Axial ODSCC Indications at TSPs 202A OR23 Soabtook SGB R11 C3 @ 08H t.l,oA Oep!h a EQ 3 % TVI, $11 0tFt.h,. 50.3%TW, To'.el L.n,Wi
- 022 WI., S:r l~,. 0. 18 h.
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- 1CSJJ* to0 Cr.ad'."ng WW:OUIJ;..lrN,v.&)
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Tl 2024 OIU3Soobtook SGB R12 C120 @ 08H t.~ Dotf°h* U!.l '.li,'TW; Ctt 0eFth*.t!l.2~ 'r\\\\:; To~ I Leoi!Cf'I
- 0.14 11'1~ C:rbngth
- O,Q~in BVIIA°tHI.R* lt>>!ip~(OO C,ad,,~WltlO!JIUQ,:IMl'IH.)
2024 OR23 StabrookSGB R12 C120 @ 08H -Flaw2
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- 55...2':,i.T\\V~ TO'.!lltt<1~*0.1e 1t-...; SYLt..ngh
- 0. 11 It'll 81.utP,a"wa~72Zl:p1t('OCC-~W,I\\M L~tl'Ct) 100 ~--------------------,-----
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I 01 2024 OR23 Seabrook SGB R17 C119 @ 01H J.ru.O,plh* 6U'J.T\\Y: 67 0.;6 *57%n V;Tctall en;6,
- Q.13 W"i_; StrlH~th ~o.OS in.
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- i 2024 OR23 Seabrook SGS R40 C104 @ 08H l,lat0*r:th*57..t%1W; Qr0f¢'1h*52..9 1W; T(l(61lffl~*0.21ifl.: SVl.*nlth*0.16 in.
ButUP\\'USJl't*il74 pst: (00Cr~Vo\\f')OU1~amttts1 t
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L._fhcMtJ 2024 OR23 Subtook 5GB R5l C40 @ 08H J.bll ~!)I
- st.:'!4n 'I; $3' D*Jth.or..c1..w.n*1: Tv.alL*nJ".h '"' O.l4 in : Str i.e"'ll'I
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Seabrook Station Docket No. 50-443 Enclosure APPENDIX B - Condition Monitoring Graphs for OR23 sec Indications L-2025-101 Page 16 of 24 Figure 4 - Profile Charts of Axial ODSCC Indications at TS Expansion Transitions 2024 OR23 Seabrook SGA R22 C61 @ TSH Max Depth= 84.3% TW; Str Depth= 69.8% TW; Total length = 0.16 in.; Sir l ength= 0.11 in.
Burst Pressure= 6323 psi; (OD Cracking Without ligaments) 100 90 80 70 3
60
"' e I-c 50 t!
~ 40
.<:; a.
2l 30 20 10 0.2 Length (Inches) 2024 OR23 Seabrook SGC R28 C57 @ TSH Max Depth= 93%TW; Sir Depth= 81.1%TW; Total l ength = 0.19 in.; Str length= 0.13 in.
Burst Pressure= 5284 psi; (OD Cracking Without Ligaments) 100 90 80 70
'ii 3
60 e
I-c 50 t!
~ 40
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2l 30 20
--\\-------------
0.1 0.2 Length (Inches)
Seabrook Station Docket No. 50-443 7000 6000 i,.. --..
-*@ODO
- a. -
~ 4000
~
~ 3000 m 2000 1000 Enclosure L-2025-101 Page 17 of 24 APPENDIX B - Condition Monitoring Graphs for OR23 SCC Indications Figure 5 - CM for Circumferential ODSCC at a DNT/DNG Condition Monitoring Circ. ODSCC
+Point Probe ETSS H-21410.1 Rev.6 I
-PDALirnit
- Flaw 3DP=3861 PDA Limit @ 3DP 20.9%
0 0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0 50.0 NOE Percent Degraded Area Seabrook OR23 SG B R4 C119 SCI PDA 100 911 "iij 80
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50 QJ
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0 30 60 90 120 150 180 210 240 270 300 330 360 Circumferential Location (Degrees)
L-2025-101 Page 18 of24 SEABROOK STATION APPENDIX C-1 OR23 SG Inspection SG-A: OR23 Bobbin Wear~ 20%TW at AVBs ROW COL VOLTS IND %TW LOCATION
==
=== ---------
19 40
- 1. 03 TWO 25 AVl +0.11 28 59 0.70 TWO 20 AV5 -0.17 0.93 TWO 24 AV2 +0.17 30 11 0.73 TWO 20 AV5 -0.23 31 12 2.03 TWO 36 AV5 +0.33 33 15 0.68 TWO 20 AV5 -0.21 34 51 0.73 TWO 20 AV3 -0.28 35 61
- 1. 28 TWO 29 AV5 -0.25
- 1. 83 TWO 34 AV4 -0.28 35 73 0.70 TWO 20 AV2 +0.14 39 79 0.68 TWO 20 AV5 -0.24 0.71 TWO 20 AV4 -0.18 40 71 0.70 TWO 20 AV2 +0.09 40 103 0.70 TWO 20 AV4 -0.14 41 50
- 1. 62 TWO 32 AV5 +0.21
- 1. 00 TWO 25 AV4 +0.20 41 53 0.86 TWO 23 AV5 -0.26 0.89 TWO 23 AV4 -0.16 41 59 0.81 TWO 22 AV2 +0.16 41 68 0.85 TWO 23 AV4 -0.07 2.18 TWO 37 AV3 +0.28 41 78 0.75 TWO 21 AV3 -0.21 42 58 0.70 TWO 20 AV3 -0.23 42 72
- 0. 96 TWO 24 AV5 -0.09
- 1. 30 TWO 29 AV4 +0.33
- 1. 52 TWO 31 AV3 -0.30 42 80 0.98 TWO 25 AV6 +0.65
- 1. 84 TWO 34 AV3 -0.25
- 1. 48 TWO 31 AV2 +0.16 44 98
- o. 72 TWO 20 AV3 +0.08 45 74
- 1. 51 TWO 31 AV3 -0.20
- 1. 85 TWO 35 AV4 +0.05 46 65 0.85 TWO 23 AV5 +0.19 46 95 0.68 TWO 20 AV6 -0.20 47 95
- 0. 72 TWO 20 AV3 +0.09 48 63 0.95 TWO 24 AV5 -0.20 0.79 TWO 22 AV4 -0.16 0.73 TWO 20 AV3 +0.09 0.85 TWO 23 AV2 +0.11 48 64 0.75 TWO 21 AV2 +0.09 49 65 0.84 TWO 22 AV4 -0.18
- 1. 78 TWO 34 AV3 +0.13 49 88
- 1. 33 TWO 29 AV5 -0.35 0.86 TWO 23 AV4 +0.12 50 85 0.74 TWO 21 AV4 +0.00 0.93 TWO 24 AV3 +0.13 50 95
- 0. 96 TWO 24 AV6 -0.21
- 1. 34 TWO 29 AV5 -0.23 51 86 0.79 TWO 22 AV2 -0.09 51 90 0.85 TWO 23 AV5 +0.12 52 88
- 1. 05 TWO 26 AV5 +0.16
- 1. 20 TWO 28 AV4 -0.17 52 89
- 1. 00 TWO 25 AV6 -0.16
- 1. 55 TWO 32 AV5 +0.20
- 0. 72 TWO 20 AV4 -0.16 Total Tubes 34 Total Records: 55
L-2025-101 Page 19 of24 SEABROOK STATION APPENDIX C-1 OR23 SG Inspection SG-B: OR23 Bobbin Wear ~ 20%TW at AVBs ROW COL VOLTS IND %TW LOCATION
==
==---
20 60 0.77 TWO 21 AV6 +0.05 0.77 TWO 21 AV6 -0.53 0.81 TWO 22 AVl +O.23 29 79 0.71 TWO 20 AV5 -0.21
- 1. 22 TWO 28 AVl -0.32 30 61 2.39 TWO 39 AV5 +0.15 0.82 TWO 22 AV2 -0.02 30 75 0.99 TWO 25 AV2 +0.20 30 81
- 1. 04 TWO 25 AV5 -0.30 0.68 TWO 20 AV2 +0.20 30 87 0.85 TWO 23 AV5 -0.25 33 109
- 1. 70 TWO 33 AV5 -0.27 35 68
- 0. 96 TWO 24 AV5 -0.05
- 0. 71 TWO 20 AV4 -0.19 0.84 TWO 22 AV3 +0.17 36 65 0.91 TWO 23 AV5 -0.28
- 1. 72 TWO 33 AV2 -0.23 37 69 0.69 TWO 20 AV2 +0.08 39 49
- 0. 72 TWO 20 AV4 -0.19 1.10 TWO 26 AV3 -0.27 0.91 TWO 23 AV2 +0.02 39 54 0.99 TWO 25 AV4 -0.19 0.88 TWO 23 AV3 -0.18 39 60 0.81 TWO 22 AV3 +0.09 41 61
- 0. 71 TWO 20 AV4 +0.00 41 75 0.88 TWO 23 AV3 +0.18 0.70 TWO 20 AV2 +0.15 43 69 0.76 TWO 21 AV5 -0.32 0.80 TWO 22 AV4 +0.21 43 75 0.98 TWO 25 AV5 +0.14
- 1. 28 TWO 29 AV4 -0.28 0.89 TWO 23 AV2 +0.12 47 71
- 1. 01 TWO 25 AV3 +0.16 0.68 TWO 20 AV2 -0.21 Total Tubes 18 Total Records: 34
L-2025-101 Page 20 of24 SEABROOK STATION APPENDIX C-1 OR23 SG Inspection SG-C: OR23 Bobbin Wear~ 20%TW at AVBs ROW COL VOLTS IND %TW LOCATION
==
35 13 1.18 TWO 27 AV5 +0.30 0.79 TWO 22 AV4 +0.16 1.17 TWO 27 AV2 -0.34 39 45
- 1. 61 TWO 32 AV5 -0.36 0.75 TWO 21 AV4 +0.00 0.88 TWO 23 AV3 +0.27 39 69
- 1. 37 TWO 30 AV5 +0.28 0.87 TWO 23 AV4 -0.27 0.76 TWO 21 AV3 +0.09 41 39 0.83 TWO 22 AV5 -0.28
- 1. 00 TWO 25 AV4 -0.11
- 1. 05 TWO 26 AV2 +0.17 41 41
- 1. 35 TWO 29 AV2 +0.22 41 43 0.85 TWO 23 AV4 -0.15 41 80 0.74 TWO 21 AV4 -0. 46
- 1. 78 TWO 34 AV3 -0.37 41 100 0.81 TWO 22 AV5 -0.17 42 23 0.75 TWO 21 AV5 -0.25
- 0. 72 TWO 20 AV4 +0.12 42 102 1. 32 TWO 29 AV4 -0.04
- 1. 46 TWO 31 AV3 +0.18 43 23 0.70 TWO 20 AV3 +0.14 43 100 1. 86 TWO 35 AV4 -0.02 43 102 1. 30 TWO 29 AV5 -0.27
- 1. 48 TWO 31 AV4 -0.22 44 100 1. 46 TWO 31 AV5 +0.05
- 1. 46 TWO 31 AV4 -0.21 46 36 0.72 TWO 20 AV5 -0.20
- 1. 40 TWO 30 AV4 +0.25 0.88 TWO 23 AV3 +0.37 46 79 0.79 TWO 22 AV4 +0.17 47 35 0.80 TWO 22 AV4 -0.15 0.78 TWO 21 AV3 -0.20 47 93
- 1. 40 TWO 30 AV5 -0.20 47 99 1.11 TWO 26 AV6 -0.28
- 1. 56 TWO 32 AV5 -0.08 49 95 0.88 TWO 23 AV5 -0.19 53 67 1.21 TWO 28 AV3 -0.29
- 1. 06 TWO 26 AV2 +0.17 Total Tubes 21 Total Records: 39
L-2025-101 SEABROOK STATION APPENDIX SG-D: OR23 Bobbin Wear ~ 20%TW at AVBs ROW COL VOLTS IND %TW LOCATION
==
===
24 6 0.81 TWD 22 AVl +o. n 0.80 TWD 22 AV6 -0.05 26 8 0.75 TWD 21 AV6 -0.74 27 8 1.12 TWD 27 AV6 +0.00 27 39 0.79 TWD 22 AV6 -0.14
- 1. 85 TWD 35 AV5 -0.27 1.19 TWD 27 AV2 +0.33 27 44 0.79 TWD 22 AV2 -0.04 28 115 0.94 TWD 24 AV6 -0. 49 29 34 0.84 TWD 22 AV2 -0.29 32 12 2.03 TWD 36 AV5 -0.20 34 69 2.24 TWD 38 AV5 -0.33 2.39 TWD 39 AV4 -0.06 0.77 TWD 21 AV3 +0.08 0.91 TWD 23 AV2 -0.16 34 73
- 1. 30 TWD 29 AV5 -0.21 2.04 TWD 36 AV4 -0.17
- 1. 28 TWD 29 AV3 +0.13 2.21 TWD 38 AV2 +0.24 34 109 0.75 TWD 21 AV5 -0.14 35 37 0.87 TWD 23 AV2 +0.17 35 69
- 1. 56 TWD 32 AV2 +0.06
- 1. 82 TWD 34 AV3 +0.19 36 82
- 0. 96 TWD 24 AV5 -0.20 0.88 TWD 23 AV4 -0.35 1.11 TWD 26 AV2 -0.22 37 16 0.82 TWD 22 AV3 +0.12 37 48 0.70 TWD 20 AV3 -0.19 37 77
- 1. 61 TWD 32 AV4 -0.23
- 1. 63 TWD 33 AV3 +0.21 39 41
- 1. 04 TWD 25 AV4 -0.21 39 44 0.71 TWD 20 AV4 -0.16 39 57 0.68 TWD 20 AV5 -0.07 0.91 TWD 23 AV2 +0.00 0.73 TWD 20 AV3 -0.03 40 66 1.19 TWD 27 AV5 -0.19 2.09 TWD 37 AV4 -0.22
- 1. 68 TWD 33 AV3 -0.27
- 1. 45 TWD 31 AV3 +0.22 41 20 0.97 TWD 24 AV5 -0.18 0.76 TWD 21 AV4 +0.22 41 56
- 1. 26 TWD 28 AV5 +0.17 0.71 TWD 20 AV4 -0.07 C-1 41 41 42 42 43 43 44 44 44 46 46 46 46 47 47 49 49 50 50 52 52 56 56 Page 21 of 24 OR23 SG Inspection ROW COL VOLTS IND %TW LOCATION
=
======
0.83 TWD 22
- 1. 63 TWD 32 59 0.99 TWD 25 66
- 1. 08 TWD 26 24 1.12 TWD 27 46 0.84 TWD 22 0.95 TWD 24 21
- 1. 07 TWD 26 0.75 TWD 21 0.88 TWD 23 51
- 1. 05 TWD 26 45 0.80 TWD 22 48
- 1. 41 TWD 30 0.70 TWD 20 0.70 TWD 20 91
- 1. 23 TWD 28
- 1. 28 TWD 29
- 1. 66 TWD 33 0.79 TWD 22 30
- 1. 68 TWD 33
- 1. 42 TWD 30 38 2.01 TWD 36 2.09 TWD 37 39
- 1. 93 TWD 35 42 0.97 TWD 24 0.91 TWD 23 49
- 0. 71 TWD 20
- 1. 65 TWD 33 53 0.89 TWD 23 52 0.84 TWD 22 0.85 TWD 23
- 1. 87 TWD 35 81 0.82 TWD 22 50 0.74 TWD 21 94
- 1. 05 TWD 26 33
- 1. 52 TWD 31 35
- 1. 20 TWD 28 0.75 TWD 21 41
- 1. 09 TWD 26
- 1. 15 TWD 27
- 1. 46 TWD 31 69 0.78 TWD 21 Total Tubes Total Records:
ROW COL VOLTS 40 66 2.69 AV3 -0.20 AV2 -0.25 AV4 +0.18 AV2 -0.19 AV4 +0.18 AV5 +0.14 AV3 -0.21 AV6 +0.16 AV5 -0.23 AV3 -0.24 AV5 +0.16 AV5 -0.20 AV3 +0.12 AV5 +0.15 AV4 -0.22 AV5 +0.14 AV4 -0.28 AV3 -0.37 AV2 +0.20 AV5 +0.21 AV4 -0.17 AV5 +0.16 AV4 -0.22 AV5 -0.22 AV5 -0.19 AV4 -0.15 AV3 -0.19 AV2 -0.19 AV5 -0.23 AV4 +0.21 AV3 +0.16 AV2 -0.20 AV4 +0.13 AV4 -0.29 AV6 -0.25 AV4 -0.05 AV5 +0.17 AV3 +0.09 AV5 -0.21 AV4 -0.29 AV2 -0.27 AV5 -0.16 46 85 IND %TW LOCATION TWD 41 AV2 -0.24 Total Tubes 1
Total Records: 1
L-2025-101 SEABROOK STATION APPENDIX C-2 OR23 SG NOTE: The "%TWu values are shown in the "UTIL 1u field.
+Point~ Wear (WAR) At Broached TSP Supports SG-A:
ROW COL VOLTS
==
4 87 0.24 5
108 0.39 18 82 0.21 22 95 0.52 Total Tubes Total Records:
SG-B:
ROW COL VOLTS
==
22 97 0.88 Total Tubes Total Records:
SG-C:
ROW COL VOLTS
==
32 24 0.90 Total Tubes Total Records:
SG-D:
ROW COL VOLTS 6
108 0.33 42 19 0.24 Total Tubes Total Records:
IND %TW WAR WAR WAR WAR 4
4 IND %TW WAR 1
1 IND %TW WAR 1
1 IND %TW WAR WAR 2
2 LOCATION 06C -0.53 06C -0.59 06C -0.61 08H -0.29 LOCATION 05H -0.53 LOCATION 04H -0.40 LOCATION 03H -0.48 03C +0.19 UTIL 1 UTIL 2
==
6 OD 96910. 1 10 OD 96910. 1 6 OD 96910.1 15 OD 96910.1 UTIL 1 UTIL 2 20 OD 96910.1 UTIL 1 UTIL 2 19 96910.1 UTIL 1 UTIL 2 9 OD 96910.1 7-96910.1 Page 22 of24
L-2025-101 SEABROOK STATION APPENDIX C-3 NOTE: The "%TW" values are shown in the "UTIL 1" field.
+Point VOL (Volumetric) Indications SG-A:
ROW COL VOLTS IND %TW LOCATION UTIL 1 UTIL 2
==
==
1 11 0.79 VOL Ole -1.68 22 OD 27906.3 1
36 0.25 VOL TSe +18.03 23-00 21998.1 1
87 0.31 VOL TSe +18.21 26 OD 21998.1 1
112 0.25 VOL OlH -2. 08 23 OD 21998.1 11 76 0.17 VOL 06e -0.72 16 OD 21998.1 12 97 0.20 VOL 05e -0. 77 18 OD 21998.1 21 26 0.19 VOL 03H-0.69 18 OD 21998.1 34 61 0.18 VOL 04H-0.40 18 OD 21998.1 35 80 0.40 VOL 03H -0.43 30 OD 21998.1 35 88 0.20 VOL 03H -1.04 20 OD 21998.1 36 93 0.17 VOL 03H -0. 75 17 OD 21998.1 49 29 0.25 VOL TSH+0.24 23 OD 21998.1 53 33 0.08 VOL TSH +0.37 7 OD 21998.1 Total Tubes 13 Total Records: 13 SG-B:
ROW COL VOLTS IND %TW LOCATION UTIL 1 UTIL 2
============ =--=====-=========-
1 11 0.41 VOL Ole
-2.05 26 OD 21998.1 1
87 0.56 VOL TSH
+17. 95 34 OD 21998.1 0.60 VOL TSe
+17.92 37 OD 21998.1 1
112 0.15 VOL OlH
-2.00 15 OD 21998.1 1
119 0.52 VOL 02H
-3.44 17 OD 27906.3 2
98 0.41 VOL 06e
-0.91 26 OD 21998.1 2
110 0.26 VOL 06e
-0.77 20 OD 21998.1 2
113 0.30 VOL 07H
+1. 09 24 OD 21998.1 5
86 0.46 VOL 04H
-0.24 15 OD 21998.1 24 101 0.15 VOL 04H
+1.15 15 OD 21998.1 43 96 0.21 VOL TSH
+0.16 20 OD 21998.1 54 87 0.18 VOL Ole
+0.61 14 OD 21998.1 58 63 0.68 VOL 07H
+1. 76 38 OD 21998.1 Total Tubes 12 Total Records: 13 Page 23 of24 OR23 SG Inspection
L-2025-101 SEABROOK STATION APPENDIX NOTE: The "%TW" values are shown in the "UTIL l" field.
+Point VOL (Volumetric) Indications SG-C:
ROW COL VOLTS IND %TW LOCATION UTIL 1 UTIL 2
=========== -====================== =--
1 87 0.48 VOL TSH +18.32 31 OD 21998.1 0.42 VOL TSC +18. 03 18 OD 27905.1 1
112 0.14 VOL Ole -1. 97 12 OD 21998.1 0.26 VOL OlH-1.84 20 OD 21998.1 3
90 0.27 VOL 07C -0. 61 22 OD 21998.1 3
113 0.37 VOL 05C -0. 82 27 OD 21998.1 4
74 0.67 VOL 04C -0.43 20 OD 27906.3 5
57 0.27 VOL 06C-0.69 24 od 21998.1 6
39 0.27 VOL 06C -0.59 24 OD 21998.1 6
40 0.48 VOL 06C -0.53 32 OD 21998.1 7
98 0.44 VOL 05C -0. 67 14 OD 27906.3 9
97 0.28 VOL 06C-0.53 9 OD 27906.3 23 6 0.47 VOL OlH -6.53 31 OD 21998.1 0.16 VOL OlH -6.19 14 OD 21998.1 28 104 0.28 VOL 05C -0. 64 22 OD 21998.1 32 35 0.06 VOL 07C+l9.60 4 OD 21998.1 39 19 0.15 VOL TSC +4. 05 14 OD 21998.1 43 26 0.23 VOL TSH +0.16 19 OD 21998.1 44 26 0.09 VOL TSH +0.11 6 OD 21998.1 Total Tubes 16 Total Records: 19 SG-D:
ROW COL VOLTS IND %TW LOCATION UTIL 1 UTIL 2 1
20 0.36 VOL 06C-0.43 27 OD 21998.1 1
87 0.38 VOL TSH +18.16 31 -OD 21998.1 5
100 0.53 VOL 06H+0.69 34 OD 21998.1 13 4 0.27 VOL OlC +0.48 22 OD 21998.1 20 28 0.39 VOL 03C+l.Ol 17 OD 27905.1 20 29 0.58 VOL 03C+0.51 22 OD 27905.1 21 28 0.23 VOL 03C+0.75 13 OD 27905.1 21 52 0.32 VOL 04H -0.48 25 OD 21998.1 36 41 0.46 VOL 04H -0.45 31 OD 21998.1 43 49 0.24 VOL 05H-0.80 20 OD 21998.1 44 100 0.32 VOL 05H-0.75 25 OD 21998.1 56 57 0.45 VOL OlH+0.48 39 OD 27901.1 Total Tubes 12 Total Records: 12 Page 24 of 24