BYRON 2020-0053, Steam Generator Tube Inspection Report for Refueling Outage 23

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Steam Generator Tube Inspection Report for Refueling Outage 23
ML20253A042
Person / Time
Site: Byron Constellation icon.png
Issue date: 09/10/2020
From: Kanavos M
Exelon Generation Co
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
BYRON 2020-0053
Download: ML20253A042 (19)
v • d • e


Text

Byron Generating Station Exelon Generation J, 4450 North German Church Rd Byron. IL 61010-9794 www.exe loncorp com September 10, 2020 LTR: BYRON 2020-0053 File: 1.10.0101 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555-0001 Byron Nuclear Power Station, Unit 1 Facility Operating License No. NPF-37 NRC Docket No. STN 50-454

Subject:

Byron Station, Unit 1 Steam Generator Tube Inspection Report for Refueling Outage 23 In accordance with Technical Specification 5.6.9, "Steam Generator (SG) Tube Inspection Report," Exelon Generation Company, LLC is reporting the results of the SG inspections that were completed during Byron Station, Unit 1 Refueling Outage 23 (81 R23).

If there are any questions regarding this submittal, please contact Ms. Zoe Cox, Regulatory Assurance Manager, at (815) 406-2800.

Respectfully,

~---

Mark Kanavos Site Vice President Byron Station

Attachment:

1) Byron Station, Unit 1 Steam Generator Tube Inspection Report Refueling Outage 23, March, 2020 cc: Regional Administrator, NRC Region Ill NRC Senior Resident Inspector - Byron Station Illinois Emergency Management Agency - Division of Nuclear Safety

September 10, 2020 LTR: BYRON 2020-0053 bee: Illinois Emergency Management Agency - Division of Nuclear Safety (with attachment)

Site Vice President - Byron Station (without attachment)

Vice President - Licensing and Regulatory Affairs (without attachment)

Director - Licensing and Regulatory Affairs (without attachment)

Manager - Licensing - Braidwood, Byron and LaSalle County Stations (without attachment)

Regulatory Assurance Manager - Byron Station (without attachment)

P.M. Creegan - Engineering Programs - Byron Station (with attachment)

Exelon Document Control Desk Licensing (with attachment)

NRC Correspondence Coordinator - Byron Station (with attachment)

Exelon Generation Company, LLC BYRON STATION UNIT 1 4450 North German Church Road Byron, Illinois 61010 COMMERCIAL OPERATION: September 16, 1985 BYRON STATION UNIT 1 STEAM GENERA TOR EDDY CURRENT INSPECTION REPORT REFUELING OUTAGE 23 March 2020 Mailing Address 4300 Winfield Road Warrenville, IL 60555 Page 1 of 17

TABLE OF CONTENTS Introduction ............................................................................................. 3 Steam Generator Inspection Scope (TS 5.6.9.a) ............................................. 3 Degradation Mechanisms Found (TS 5.6.9.b) .................................................. 5 Nondestructive Examination Techniques Utilized for Each Degradation Mechanism Found During 81 R20 (TS 5.6.9.c) ................................................ 5 Location, Orientation (if linear), and Measured Sizes of Service Induced Indications (TS 5.6.9.d) .............................................................................5 Plugging Summary (TS 5.6.9.e and TS 5.6.9.f) ............................................... 7 Results of Condition Monitoring (TS 5.6.9.g) .................................................. 8 Attachment A - Fan Bar Wear Indications ................................................... 10-16 Page 2 of 17

Introduction Byron Station Unit 1 operates with four Babcock & Wilcox Replacement Steam Generators (SGs) in a four loop pressurized water reactor system. Each SG contains 6633 thermally treated Alloy-690TT U-tubes that have a nominal diameter of 0.6875 inches and a nominal wall thickness of 0.040 inches. The tubes are supported by stainless steel lattice grid structures and fan bars. The tubes are hydraulically expanded into the full depth of the tubesheet. Main Feedwater enters the SGs above the tube bundle through a feedring and J-tubes. The replacement SGs were installed during the eighth (8 th ) refueling outage in 1998.

Technical Specification (TS) 5.5.9.d provides the requirements for SG inspection frequencies and requires periodic SG tube inspections to be performed. TS 5.5.9.d requires that 100% of the Unit 1 tubes are to be inspected at sequential periods of 144,120, 96, and thereafter 72 Effective Full Power Months (EFPM). The first sequential period shall be considered to begin after the first inservice inspection of the SGs.

The Byron Unit 1 replacement SGs are currently in their fifteen (15th ) cycle of operation and are on an 18-month fuel cycle. During Cycles 21, 22, and 23, Byron Unit 1 operated a total of 4.262 Effective Full Power Year (EFPY) since the previous SG inspection during 81 R20. The replacement SGs have operated a total of 20.8 EFPY through the end of Cycle 23, which is 93.4 EFPM into the 120 EFPM inspection period.

The B 1R23 SG inspections were performed consistent with the Electric Power Research Institute (EPRI) "PWR Steam Generator Examination Guidelines: Revision 8," applicable interim guidance and Nuclear Energy Institute (NEI) 97-06, "Steam Generator Program Guidelines" Revision 3. The field inspection activities (manway to manway) were conducted from March 11, 2020 through March 20, 2020 by the Westinghouse Electric Company LLC.

Steam Generator Inspection Scope (TS 5.6.9.a)

Byron Unit 1 Refueling Outage 23 (81 R23) was the sixth outage and second SG inspection of the 120 EFPM period. The following inspections were performed during B1R23 to ensure that 100% of the tubes were inspected during the period as required by TS 5.5.9.d.

Primary Side Scope:

  • 100% full-length bobbin coil eddy current examination of all four SGs
  • All Hot leg Dent & Dings ~2.0 volts, Plus-Point in all four SGs
  • 53% peripheral X-Probe examination from tube end to the 1st lattice grid on the Hot Leg for potential foreign objects and associated wear (peripheral locations based on crossflow velocities being the highest)
  • 47% of peripheral X-Probe examination from tube end to the 1st lattice grid on the Cold Leg for potential foreign objects and associated wear Secondary Side Scope:
  • Sludge lancing in all four SGs including "post sludge lance" Foreign Object Search and Retrieval (FOSAR)
  • Feedring Inspection (1 D SG)
  • Steam Drum Internal Inspections (1 C & 1D SG)
  • Upper Bundle Inspection (1 D SG)

Page 3 of 17

Other SG Inspections:

Visual Inspection of Installed Tube Plugs - All previously installed hot leg and cold leg tube plugs (42) were visually inspected for signs of degradation and leakage.

No degradation or anomalies were found.

SG Channel Head Bowl Visual Inspections- Each SG hot & cold leg primary channel head was visually examined in accordance with the recommendations of Westinghouse NSAL 12-01 and NRC IN 2013-20 for evidence of cracking or breaches in the cladding or divider to channel head weld and for evidence of wastage of the carbon steel channel head. No evidence of cladding or weld cracking or breaches or evidence of channel head wastage was identified.

Secondary Side Visual Inspections - Top of Tubesheet (TTS) sludge lancing was performed during 81 R23 and visual inspection of the secondary tubesheet was performed following sludge lancing activities in all four SGs. The tube annulus, tube lane, and peripheral tubes (6-8 tubes deep) were visually inspected for foreign material. Additionally, FOSAR of all SGs was performed, which included in-bundle eight columns, no tube lane, and annulus as well as for all confirmed eddy current possible loose part (PLP) calls. A total of seven (7) metallic foreign objects were found during inspections. Five (5) of these foreign objects; (2) retainer springs, (1) weld slag, (2) metal objects, were removed from the SGs. There are two foreign objects remaining. One small wire bristle which is considered benign based on having no known history of causing tube wear in the industry. The second is a small metallic object located in a low flow velocity zone, which will not cause significant tube wear, thus can remain in the SG. One tube was required to be plugged due to foreign object wear from a retaining spring remnant located in the 1BSG.

During visual inspections in the 1D SG of the lattice grids at the uppermost (9th )

support location for the hot leg and cold leg some deposit accumulation was identified on the hot leg side at the lattice grids and on the tube surfaces. The corresponding cold leg was relatively free of deposit accumulation at the lattice grids and on the tube surfaces, as evidenced by sharply defined lattice grid edges and shiny tube surfaces. No degradation was noted on either leg.

During the Feedring inspections in the 1D SG, no anomalous structural conditions or foreign objects were observed. Additionally, no erosion or component degradation was identified.

Steam drum visual inspections were performed in the 1C and 1D SGs. No evidence of foreign material, degradation or structural distortion was observed in the steam drum. The primary and secondary moisture separators were in good condition.

No repairs were required for the secondary side inspection, and it was concluded that a 4-cycle inspection interval was justified with no adverse consequences for all 4SGs.

Page 4 of 17

Degradation Mechanisms Found (TS 5.6.9.b)

The Table below provides a summary of all the degradation, by mechanism, identified during the 81 R23 inspections (all mechanisms were present during previous inspections). No evidence of any cracking was found .

summary of B1R23 Degra daf10n Ind"1cafions b,v Mec hamsm Degradation Mechanism lASG 1B SG lC SG lDSG Total Fan Bar Wear 25 104 31 59 219 Lattice Grid Wear 6 3 1 3 13 Foreign Object Wear 0 5 1 0 6 Nondestructive Examination Techniques Utilized for Each Degradation Mechanism Found During B1 R23 (TS 5.6.9.c)

Steam Generator eddy current examination techniques used (see Table 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 Byron Station Unit 1 SGs during B1R23.

EPRIA,ppen d"1x HTech. mques EPRI Degradation Location Orientation EPRI ETSS ETSS Probe Mode Rev Fan Bar Wear Vol 96004.3 (D&S) 13 Bobbin Lattice Grid Wear Vol 96004.3 (D&S) 13 Bobbin 27091.2 (D) 2 Bobbin Foreign Object @ top 1790X.1 (D) 0 X-Probe of tubesheet or lattice Wear Vol 21998.1 (S) 4 +Point grid 27901.1 (S) 1 +Point (D) = Detection (S) = Sizing Location, Orientation (if linear), and Measured Sizes of Service Induced Indications (TS 5.6.9.d)

1. Fan Bar Wear - A total of 219 indications of fan bar wear were found in the Steam Generators. The deepest indication measured 21 %TW as measured by the EPRI Appendix H qualified bobbin coil examination technique 96004.3 which is consistent with results from previous inspections. No tubes were plugged as a result of fan bar wear.

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The Table below provides a summary of Fan bar wear degradation. Refer to Attachment A for detailed locations and sizing for all Fan Bar wear indications.

B1R23 Fan Bar W ear Summarv 1ASG 1BSG 1CSG 1DSG Total Indications Indications Indications Indications

<10% TW 18 69 27 36 150 10-19% TW 7 34 4 23 68

>=20%TW 0 1 0 0 1 TOTAL 25 104 31 59 219

2. Lattice Grid Wear-Thirteen (13) indications of wear related to the lattice grid supports were reported during the B1 R23 outage (see table below). The deepest indication measured 11 %TW as measured by the EPRI Appendix H qualified bobbin coil examination technique 96004.3. All of these indications were reported in the previous outage with minimal growth. No tubes were plugged as a result of lattice grid wear. Table below provides a listing of all tubes that contain lattice grid wear.

B1R23 Latt1ce G r1"dWearn Id"1cat1on L"1stmg B1R23 New or SG Row Col Location Depth Repeat

(%TW)

SG1A 46 93 02C +1 .21 4 Repeat SG1A 62 103 07H +1 .25 7 Repeat SG1A 69 94 07H +1 .38 6 Repeat SG1A 82 103 07H -0.68 6 Repeat SG1A 84 93 07H +1.34 6 Repeat SG1A 94 57 07H +0.99 11 Repeat SG1B 11 32 05H -1 .46 7 Repeat SG1B 43 72 02H -1.61 5 Repeat SG1B 118 73 07H +1.63 11 Repeat SG1C 21 142 07H -1.31 6 Repeat SG1D 8 1 06C -1.64 4 Repeat SG 1D 51 8 08C -1.48 8 Repeat SG1D 117 78 07H +0.58 10 Repeat

3. Foreign Object Wear - As shown in the table below, a total of 5 indications of secondary side foreign object (FO) wear were identified at the hot leg top of tubesheet (TSH) during B1 R23. All of these five indications were depth sized using the +Point probe and Examination Technique Specification Sheet (ETSS) 27901 .1. One of these wear indications exceeded 40% TW and that tube was plugged. The other four (4) tubes had wear indications less than 40% TW and were left in service since the foreign object causing the wear was removed.

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B1R23 Fore1gn Ob"1Ject Wear B1R23 B1R23 B1R23

+Point Axial Circumferential SG Row Col Location Depth Extent Extent (3/4TW) (Inches) (Inches)

SG1B 1 82 TSH +0.15 30%TW 0.2" 0.41" SG1B 2 81 TSH +0.17 51%TW" 0.3" 0.49" SG1B 3 82 TSH +0.26 25%TW 0.18" 0.37" SG1B 4 81 TSH +0.20 22%TW 0.18" 0.35" SG1B 5 82 TSH +0.09 20%TW 0.15" 0.35" SG1C 16 81 03H +0.73 18%TW 0.11" 0.18"

  • Tube R2C81 was plugged ~40%TW The newly identified indication of secondary side FO wear triggered additional +Point' inspection of the surrounding tubes to make certain that the wear region was adequately bounded. In addition, +Point' inspections were performed on tubes surrounding all detected secondary side FOs to ensure that no wear had resulted from the objects.

In addition, one previous indication of foreign object wear in R16 C81 in SG 1C at a 03H lattice grid intersection was again reported (see table above). It was located between contact points with the lattice grid and is, therefore, not typical lattice grid wear. Although there was no foreign object present, this indication was assumed to have been caused by a migratory foreign object. Consistent with the sizing from the B 1R20 inspection, it had a measured depth of 18%TW using +Point' Examination Technique Specification Sheet (ETSS) 21998.1. Since the object that presumably caused the indication is no longer present and the measured depth was less than the Technical Specification limit of 40% TW, this tube was left in service.

Plugging Summary (TS 5.6.9.e and TS 5.6.9.f)

As a result of the B1 R23 SG inspections, performed in accordance with TS 5.5.9.d, the modes of tube degradation found were Fan Bar wear, Lattice Grid wear, and secondary side foreign object (FO) wear. Based on the low severity degradation found in 81 R23, one tube was required to be removed from service due to exceeding the 40% TW TS limit (see tables on next page).

Note: There are no approved tube repair methods for the Unit 1 SGs. No tube sleeving was performed.

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81 R23 Tube Plugging by Degradation Mechanism (TS 5.6.9.e)

Degradation Mechanism 1ASG 1BSG 1CSG 1DSG Total Fan Bar Wear 0 0 0 0 0 Lattice Grid Wear 0 0 0 0 0 Foreign Object Wear 0 1 0 0 1 Preventative 0 0 0 0 0 Total Pluaaed during 81 R23 0 1 0 0 1 Tube Plugging to Date Number and Percentaae oer SG) (TS 5.6.9.f) 1ASG 1BSG 1CSG 1DSG Total Total Plugged during 81 R23 0 1 0 0 1 Total Stabilized during 81 R23 0 0 0 0 0 Total Pluaaed throuah 81 R23 1 2 14 5 22 Total Percent Plugged through 0.02% 0.03% 0.21% 0.08% 0.08%

B1R23 Results of Condition Monitoring (TS 5.6.9.g)

A condition monitoring assessment was performed for each inservice degradation mechanism found during the 81 R23 SG inspection. The condition monitoring assessment was performed in accordance with TS 5.5.9.a and NEI 97-06 Rev. 3 using the EPRI Steam Generator Integrity Assessment Guidelines, Revision 4. For each identified degradation mechanism, the as-found condition was compared to the appropriate performance criteria for tube structural integrity, accident induced leakage, and operational leakage as defined in TS 5.5.9.b. For each degradation mechanism a tube structural limit was determined to ensure that SG tube integrity would be maintained over the full range of normal operating conditions, all anticipated transients in the design specifications, and design basis accidents. This includes retaining a safety factor of 3.0 against burst under normal steady state full power operation primary to secondary pressure differential and a safety factor of 1.4 against burst under the limiting design basis accident pressure differential. The structural limits for wear related degradation were performed in accordance with the EPRI Steam Generator Integrity Assessment Guidelines and the EPRI Steam Generator Degradation Specific Management Flaw Handbook, Revision 2 (Flaw Handbook).

The as-found condition of each degradation mechanism found during the 81 R23 outage was shown to meet the appropriate limiting structural integrity performance parameter with a probability of survival of 0.95 at 50% confidence, including consideration of relevant uncertainties thus satisfying the condition monitoring requirements. The NOE measured flaw depths are compared to the structural integrity condition monitoring (CM) limits, which account for tube material strength, burst relation, and NOE measurement uncertainties with a 0.95 probability at 50% confidence. Therefore, the NDE measured flaw sizes are directly compared to the CM limit. No indications met the requirements for proof or leakage testing; therefore, no In Situ Pressure tests were performed during 81 R23. In addition, no tube pulls were performed during 81 R23.

Page 8 of 17

Byron Station Unit 1 did not observe any SG primary to secondary operational leakage over the last 3 operating cycles preceding the inspection. This is based on chemistry sampling taken from the Steam Jet Air Ejector, liquid SG blowdown sample locations, and no potential sources of tube leakage were found during SG tube inspections.

The sections below provide a summary of the condition monitoring assessment for each degradation mechanism found during 81 R23.

Fan Bar Wear- The largest Fan Bar wear indication found during the 81 R23 inspection was 21%TW as measured by the EPRI Appendix H qualified technique 96004.3, Rev.

13. This is well below the Fan Bar wear structural limit and CM limit curves. No tubes were required to be plugged.

Lattice Grid Wear- The largest Lattice Grid wear indication found during the B 1R23 inspection was 11 %TW, as measured by the EPRI Appendix H qualified technique 96004.3, Rev. 13. This is well below the Lattice Grid wear structural limit and CM limit curves. No tubes were required to be plugged.

Foreign Object Wear - The largest foreign object wear indication found during the B 1R23 inspection was 51%TWwith axial length of 0.3 inches as measured by the EPRI Appendix H qualified technique 27901.1, Revision 1. This indication was below the Foreign Object wear CM limit of~ 68% TW but required the tube (R2C81) to be plugged based on exceeding the 40% TW TS plugging limit.

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ATTACHMENT A 1A SG Fan Bar Wear Indications SG ROW COL %TW Support INCH 1A 78 51 13 F05 0.73 1A 66 55 5 F05 -1.08 1A 70 55 6 F03 0.95 1A 53 58 4 FOG 0.54 1A 75 58 8 F05 -0.7 1A 86 59 4 F04 1.66 1A 73 62 5 F05 -0.73 1A 72 63 5 F05 -1.41 1A 100 63 6 F05 -1.24 1A 112 63 13 F04 0.56 1A 64 65 10 FOG 0.76 1A 80 67 6 FOG -1.21 1A 84 69 5 FOG -0.52 1A 86 69 8 FOG -0.42 1A 88 69 7 FOG -0.73 1A 96 69 11 F05 -1.2 1A 96 69 12 FOG -0.88 1A 89 70 3 F09 -0.53 1A 86 71 6 F05 -1.47 1A 86 71 6 F05 -0.61 1A 86 71 14 FOG 0.94 1A 114 71 6 F05 -1.5 1A 115 78 10 F05 1.74 1A 113 80 9 F05 -1.11 1A 60 93 4 FOG -1.77 Page 10 of 17

ATTACHMENT A 1B SG Fan Bar Wear Indications SG ROW COL %TW Support INCH 1B 79 52 4 F05 0.99 1B 102 53 8 F04 -1.37 1B 102 53 7 F04 0.85 1B 102 53 8 F05 -1.3 1B 102 53 9 F05 1.35 1B 102 53 11 FOG -0.72 1B 102 53 10 FOG 1.36 1B 42 55 4 F05 0.44 1B 109 56 7 F05 -0.51 1B 109 56 6 F07 0.77 1B 109 56 8 F08 1.81 18 64 57 16 FOG -1.14 18 75 60 10 F02 -1.68 18 60 61 11 FOG -0.57 1B 67 62 11 FOl -1.58 18 81 62 8 FOG 0.95 18 60 63 4 F05 0.48 18 66 63 5 F04 1.41 18 68 63 6 F05 -1.54 18 82 63 13 FOG 1.61 1B 86 63 13 F05 -0.89 1B 86 63 21 FOG 1.46 18 88 63 10 F08 0.59 18 106 63 13 F05 -1.15 18 106 63 7 F05 1.17 18 106 63 10 F07 1.66 18 114 63 7 F05 1.51 1B 114 63 8 FOG 0.73 18 114 63 12 F07 1.76 1B 114 63 10 F08 0.81 18 65 64 11 F05 0.65 18 77 64 14 F05 -1.34 18 77 64 8 F05 0.66 Page 11 of 17

ATTACHMENT A 1B SG Fan Bar Wear Indications SG ROW COL %TW Support INCH 18 91 64 11 FOG -0.94 18 97 64 9 F05 1.08 18 97 64 15 FOG -0.48 18 113 64 8 F04 0.85 18 113 64 6 F07 0.71 18 52 65 8 F04 -1.67 18 66 65 5 F03 -1.51 18 74 65 10 FOG 1.64 18 76 65 10 F05 0.49 18 90 65 10 F05 1.48 18 90 65 7 FOG -1.29 18 106 65 6 F05 1.76 18 106 65 7 FOG -1.27 18 110 65 12 FOG 0.9 18 112 65 10 F05 1.87 18 112 65 11 FOG -1.47 18 67 66 7 FOG 0.79 18 79 66 7 FOG -1.63 18 95 66 9 F05 -0.78 18 109 66 10 F04 -1.12 18 109 66 11 F04 1.12 18 109 66 11 F05 1.27 18 109 66 12 F08 -1.57 18 113 66 11 F03 1.16 18 113 66 11 F05 -1.25 18 91 68 9 F07 1.68 18 97 68 11 FOG -1.23 18 46 69 8 FOG 0.79 1B 88 69 10 F05 1.59 18 63 70 7 F05 1.14 18 109 70 7 F05 0.68 18 43 72 9 FOG -0.76 Page 12 of 17

ATTACHMENT A 1B SG Fan Bar Wear Indications SG ROW COL %TW Support INCH 1B 95 72 7 F05 0.97 1B 92 73 7 FOG 1.65 1B 101 74 8 F05 1.73 1B 88 75 8 FOG -0.55 1B 100 75 5 FOG 1.7 1B 51 76 6 F05 1.53 1B 97 76 9 F09 -0.43 1B 109 76 9 F05 -0.41 1B 109 76 13 FOG 1.47 1B 109 76 9 F07 -1.02 1B 109 76 7 F07 0.84 1B 109 76 4 F09 0.47 1B 94 77 7 F07 1.85 1B 104 77 5 F05 -1.73 1B 108 77 4 F07 -0.66 1B 110 77 7 F05 1.14 1B 109 78 5 F02 -1.57 1B 56 79 5 FOG -0.64 1B 114 79 5 F05 1.44 1B 103 80 6 FOG 0.38 1B 111 80 7 FOG 0.69 1B 82 81 6 F05 -1.84 1B 94 81 10 F05 1.82 1B 84 83 9 F05 -1.66 1B 35 84 4 F05 -0.63 1B 105 84 7 F05 -0.49 1B 94 85 5 FOG -1.23 1B 110 85 11 FOS 0.76 1B 65 86 8 FOG 0.7 1B 64 87 7 F05 -0.84 1B 65 88 9 FOG -0.4 1B 69 88 6 FOG -0.62 1B 59 90 6 F05 -0.72 1B 87 90 9 FOG 1.61 1B 113 90 4 F07 0.92 1B 109 92 5 F04 -1.59 1B 63 94 5 FOG 1.66 1B 85 98 3 F07 1.78 1B 102 107 8 F05 -0.7 Page 13 of 17

ATTACHMENT A 1C SG Fan Bar Wear Indications SG ROW COL %TW Support INCH lC 47 14 6 F05 0.92 lC 41 38 4 F05 -1.69 lC 45 46 4 F05 -1.77 lC 56 47 3 F04 0.74 lC 87 64 4 F05 1.36 lC 40 67 3 F05 0.79 lC 48 69 3 FOG 0.76 lC 70 71 6 F05 1.5 lC 71 72 6 F07 -0.51 lC 63 76 6 F05 1.83 lC 102 77 3 F04 -1.82 lC 109 78 4 F05 -1.03 lC 52 79 5 F05 -1.77 lC 98 79 9 F05 -1.62 lC 113 80 14 F04 1.34 lC 113 80 5 F05 0.7 lC 60 81 4 F05 1.53 lC 76 81 5 F05 -1.78 lC 76 81 9 FOG -1 lC 94 81 9 F05 -1.38 lC 97 84 10 F05 -0.68 lC 97 84 10 FOG -0.91 lC 109 84 12 F04 0.59 lC 109 84 4 F05 0.64 lC 109 84 9 FOG 1.39 lC 52 85 5 F05 0.69 lC 90 85 9 F05 -1.57 lC 48 87 4 F05 -1.79 lC 100 89 6 F05 -0.75 lC 53 92 7 F05 -0.98 lC 99 94 6 F03 0.75 Page 14 of 17

ATTACHMENT A 1DSG Fan Bar Wear Indications SG ROW COL %TW Support INCH 1D 102 55 10 F05 1.58 1D 80 57 5 FOG -0.92 1D 106 57 4 F07 -1.7 1D 112 57 5 FOB -1.79 1D 113 58 8 FOG 0.69 1D 78 59 6 F05 1.75 1D 78 59 13 FOG 1.72 1D 86 59 10 F05 1.79 1D 86 59 9 FOG 1.33 1D 98 59 8 F05 1.82 1D 100 59 10 F05 1.76 1D 107 60 7 F05 1.62 1D 107 60 14 FOG -0.48 1D 107 60 7 F07 0.84 1D 70 61 7 F07 1.92 1D 112 61 11 FOG 1.34 1D 91 62 5 FOG 0.7 1D 102 63 13 F05 1.3 1D 102 63 6 FOG -1.38 1D 106 63 9 F04 0.98 1D 106 63 9 F05 1.21 1D 77 64 8 F07 0.74 1D 113 64 4 F04 -1.6 1D 113 64 9 F05 -0.77 1D 113 64 6 FOG 1.88 1D 113 64 7 F09 -0.74 1D 72 65 11 FOG 1.45 1D 76 65 10 FOG 1.77 1D 80 65 7 FOG 1.83 1D 84 65 10 FOG 1.77 1D 106 65 12 FOG -1.31 1D 106 65 12 F07 1.78 1D 89 66 7 F06 1.27 1D 99 66 10 F05 1.41 Page 15 of 17

ATTACHMENT A 1D SG Fan Bar Wear Indications SG ROW COL %TW Support INCH 1D 105 66 11 F05 1.75 1D 82 67 11 FOG 1.39 1D 90 67 11 FOG 1.44 1D 92 67 11 FOG 1.3 1D 102 67 13 FOG 1.64 1D 106 67 6 F05 -0.8 1D 106 67 11 FOG 1.78 1D 108 67 4 F08 1.95 1D 112 67 5 F05 -1.08 1D 73 68 5 F05 -0.55 1D 103 68 13 FOG 0.87 1D 107 68 8 FOG 0.67 1D 113 68 9 FOG 1.09 1D 112 69 9 F04 0.7 1D 112 69 11 F05 -1.42 1D 112 69 14 FOG 1.18 1D 83 76 7 F05 -1.14 1D 58 79 8 FOG 0.65 1D 69 82 10 F05 -0.96 1D 67 84 9 FOG 1.41 1D 75 84 8 FOG 1.8 1D 79 84 8 F05 0.94 1D 65 90 7 FOG 1.66 1D 70 95 5 FOG -1.25 1D 63 104 3 FOG 1.35 Page 16 of 17

ATTACHMENT B Byron Unit-1 SG Support Plates 1B cB ci 9

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