May 14, 2019

Dominion Energy South Carolina, Inc. Mailing Address: PO Box 88 Jenkinsville, SC 29065 DominionEnergySC.com

Document Control Desk U.S. Nuclear Regulatory Commission Washington , DC 20555

DOMINION ENERGY SOUTH CAROLINA, INC. VIRGIL C. SUMMER NUCLEAR STATION (VCSNS) UNIT 1

Serial No. 19-200 VCS UC/BAB/Rev 0 Docket No. 50-395 License No. NPF-12

SPECIAL REPORT (SPR) 2019-002 - STEAM GENERATOR TUBE INSPECTION REPORT

South Carolina Electric & Gas Company (SCE&G) hereby submits the Steam Generator Tube Inspection Report pursuant to the requirements of Technical Specifications 6.9.1 .12. This report summarizes the examination conducted during the 2018 Fall Refueling (RF-24) and the state of the three steam generators installed at V. C. Summer Nuclear Station (VCSNS), Unit 1.

On April 29, 2019 SCE&G, which is authorized under Facility Operating License NPF-12 to operate and possess Virgil C. Summer Nuclear Station Unit 1, changed its name to Dominion Energy South Carolina, Inc. SCE&G will be requesting a license amendment to reflect this name change, in the near future.

Should you have any questions, please call Michael Moore at (803)345-4752.

Sincerly, ~

Georg . Lippard Site Vice President V.C. Summer Nuclear Station

Commitments contained in this letter: None

Enclosure: RF-24 Steam Generator Tube Inspection Report

cc: G. J. Lindamood - Santee Cooper C. Haney - NRC Region II S. A. Williams - NRC Project Mgr. NRC Resident Inspector

Serial No. 19-200 Enclosure: Page 1 of 9

Steam Generator Tube Inspection Report VC Summer Nuclear Station

Jenkinsville SC 29065

RF-24 Fall 2018

1.0 Background

Commissioned in January 1984, VC Summer originally had three Westinghouse Model D3 steam generators. The original steam generators (SGs) were replaced with Westinghouse Delta- 75 steam generators in the fall of 1994.

Each of the replacement steam generators contains 6307 thermally tTeated alloy 690 tubes with an outside diameter of 0.6875 inches and a nominal wall thickness of 0.040 inches. Stress relief was performed during fabrication on the U-bends of the first 17 rows of tubing. The straight sections of the tubing are suppo1ted by nine tube support plates made of 1.125" thick, SA-240, Type 405 stainless steel. The tube support plates (TSP) have trefoil, broached holes which reduce d1yout and the collection of impurities at the tube-to­support plate intersections. The u-bend sections of the tubing are suppmied by four sets of anti-vibration bars (A VB) made of SA-240, Type 405 stainless steel. A flow distribution baffle (FDB) plate is located between the tubesheet and the lowest support plate. The flow distribution baffle increases the secondary side flow velocity near the tubesheet, thus reducing the accumulation of sludge at the top of the tubeshcet.

The D-75 steam generators contain a sludge collector above each primary separator which is designed to reduce the accumulation of sludge at the tubesheet. The tube-to-tubesheet joints are formed by a full depth hydraulic expansion and a weld to the primary cladding on the tubesheet.

2.0 Scope of Inspections Performed on Each SG

The RF-24 inspection program, as required by the EPRI PWR SG Examination Guidelines Revision 8, addressed the existing and potential degradation mechanisms for VC Summer. The defined scope included the following:

Bobbin Coil Examinations (all 3 SGs) • 100% full length tube-end to tube-end • Deposit mapping • Top ofTubesheet sludge height reporting • Monitoring for tube-to-tube wear

Array Probe Examinations (all 3 SGs unless otherwise noted) • l 00% Hot Leg Top of the Tubesheet (TIS) • Tubesheet periphery and no-tube lane 2-tubes deep on the Cold Leg Top of the Tubesheet.

o In SG A, 420 additional tubes in the high flow region, on the Cold Leg Top of the Tubesheet, were also inspected.

• All 2009 sludge (SLG) indications plus 50% of the remaining adjacent tubes making up the sludge region.

• Legacy foreign objects/possible loose parts (PLP) • RF-24 foreign objects • Special interest not performed by +PointTM

Serial No. 19-200 Enclosure: Page 2 of 9

+Poinfl'M Probe Examinations (all 3 SGs unless otherwise noted) • RF-24 Dents/Dings > 5 Volts • RF-21 bulge (BLG) indications • 20% Row I and 20% Row 2 U-bends (SG C Only) • All Array I-Codes • All Bobbin I-Codes not captured by Array • All permeability variations (PVN) • All foreign object wear • All anti-vibration bar (A VB) wear with a corresponding dent • All new dent (ONT) or ding (ONG) or bulge (BLG) • Support wear sizing and/or profiling

Primary Side Visual Inspections (all 3 SGs) • Tube plugs • SG channel head bowl cladding and internal surfaces as recommended by Nuclear Safety Advisory

Letter (NSAL) 12-1 Revision 1.

Secondary Side Activities (all 3 SGs unless otherwise noted) • Sludge lancing • Sludge collector cleaning • Top ofTubesheet Inspections/Foreign Object Search and Retrieval (FOSAR) • Top of 9th Tube Support Plate (TSP) inspections • Steam Drum Inspections

3.0 Degradation Mechanisms Found

Existing degradation mechanisms are those mechanical or corrosive processes previously and/or currently observed in a Steam Generator. The existing degradation mechanisms within the VC Summer replacement steam generators are outlined below.

3.1 Anti-Vibration Bar (A VB) Wear Wear related to tube interaction with A VB supports results from flow-induced vibration in the upper bundle. This mechanical process is related to the tightness of the upper bundle assembly as expressed in the distribution of tube-to-A VB gaps. Indications of AVB wear in the replacement steam generators were first reported during RF-12. During RF-24, a total of four (4) AVB wear indications were detected in three (3) tubes across all SGs combined. Three (3) AVB wear indications were reported in SG A, zero (0) indications reported in SG B, and one (I) indication reported in SOC. All reported AVD wear was repeat wear, meaning no new AVB wear was reported. The maximum AVB wear depth was 11%TW. None of the AVB wear indications exceeded the Condition Monitoring (CM) limit. Table 3-1 summarizes the RF-24 inspection results for A VB wear.

Table 3-1: RF-24 AVH Wear

SG Total Repeat New Repeat New Tubes / fudications Tubes I fudicalions Tubes / fudications Max%TW Ma.."'C%TW

A 2/3 2 / 3 0 / 0 11 NIA

B 0/0 010 0 / 0 NIA NIA

C l / l 111 0 / 0 6 NIA

All 3 / 4 3 14 0 / 0 11 NIA

Serial No. 19-200 Enclosure: Page 3 of 9

3.2 Tube Support Plate (TSP) Wear Flow-induced vibration that causes tube wear at TSPs and FDBs is governed primarily by secondary side thermal hydraulic characteristics and the geometry (sizes of the tube-to-support gaps, TSP spacing, etc.). Tube wear at TSPs was first reported in the replacement steam generators during RF-15. During RF-24, a total of one-hundred-fourteen (114) TSP wear indications were detected in eighty-nine (89) tubes across all SGs combined. There were thirty-four (34) TSP weru· indications reported in SG A, fifty-seven (57) indications rep01ted in SG B, and twenty-three (23) indications repo1ted in SG C. Of these, there were seventy-three (73) repeat indications (in 52 repeat tubes) and fo1ty-one (41) new TSP indications (in 37 new tubes). The maximum depth of repeat TSP wear was 35%TW. The maximum depth of new TSP wear was 19%TW. None of the TSP wear indications exceeded the Condition Monitoring (CM) limit. Table 3-2 summarizes the RF-24 inspection results for TSP wear.

Table 3-2: RF-24 TSP Wear

SG Total Reneat Nen• Repeat New Tubes / fudications Tubes I Indications Tubes / fudications Ma.'f{%TW Max %T\\T

A 27 / 34 11 116 l6 / 18 35 19

B 42/ 57 26 141 l6 / 16 21 16

C 10 / 23 15 11'6 5/7 22 10

All &9 I 114 52 173 37 / 41 35 19

3.3 Flow Distribution Baffle (FDB) Wear Flow-induced vibration that causes tube wear at TSPs and FDBs is governed primarily by secondary side thermal hydraulic characteristics and the geometry (sizes of the tube-to-support gaps, TSP spacing, etc.). Tube wear at the FDB was first reported in the replacement steam generators during RF-18. During RF-24, a total of three (3) FDB wear indications were detected in three (3) tubes. All FDB weru· indications were reported in SG C, meaning there were zero (0) FDB wear indications reported in SG A and zero (0) FDB wear indications reported in SG B. All the FDB indications were repeat indications (no new FDB wear detected at RF-24) with two of the repeat indications being previously repo1ted (at RF-21) as foreign object wear at the FDB. The maximum depth ofFDB wear reported during RF-24 was 22%TW. None of the FDB wear indications exceeded the Condition Monitoring (CM) limit. Table 3-3 summarizes the RF-24 inspection results for FDB wear.

Table 3-3: RF-24 FDB Wear

SG Total Repeat New Repeat New

Tubes / fudications Tubes I Indications Tubes / fuclications Ma.'f{%TW Mu %TW

A 0/ 0 0 10 0 / 0 NIA NIA

B 0 / 0 0 10 0 / 0 NIA NIA

C 3/ 3 3 13 0 / 0 12 NIA

All 3 / 3 3 13 0 / 0 22 NIA

3.4 Foreign Object Wear Foreign objects may enter the SGs through the feedwater stream and may cause tube wear. Foreign object wear was detected during RF-24 inspections. During RF-24, foreign object wear was detected in SG A and SG B. There were two (2) foreign object wear indications reported in SG A (tubes R25-C72 of 45%TW and RI 1 O-C77 of 7%TW), two (2) indications reported in SG B (tubes R91-C88 of 43%TW and R92-C87 of 30%TW), and zero (0) indications reported in SG C. The maximum depth of foreign object wear was

Serial No. 19-200 Enclosure: Page 4 of 9

45%TW. None of the Foreig11 Object wear indications exceeded the Condition Monitoring (CM) limit. Table 3-4 summarizes the RF-24 inspection results for foreign object wear.

Table 3-4: RF-24 Foreign Object Wear

SG Total Reneat New Ren eat New

Tubes / Indications Tubes I hldications Tubes / Indications Max%T\V Max%T\V

A 2/2 0 / 0 2 /2 NIA 45

B 2 /2 0 1' 0 2 12 NIA 43

C 0 / 0 0 / 0 0 / 0 NIA NIA

All 4 / 4 0 /0 0 / 0 NIA 45

4.0 NDE Techniques for each Degradation Mechanism

Examination Technique Specification Sheets (ETSS) identified in the RF-24 Degradation Assessment for each degradation mechanism are identified in Table 4-1.

a e - : u e T bl 4 1 SGT b D eera a 10n ec amsms an d f M h dA SSOCia ec ec rn1ques . t I NDE T I .

Probe EPRI ETSS Demonstrated Applicability-

Extended Applicability Detection/Sizing Damage Mechanism

Bobbin 96041.1 (R5)

AVB Wear None Bobbin Detection MAPOD-J Bobbin Sizing

Bobbin 96042. l (R.4)

Drilled TSP Wear None Bobbin Detection MAPOD-I Bobbin Sizing

Bobbin 96004.1 (Rl3) Support Wear (AVB, TSP, None

Bobbin Detection FOB) Bobbin Sizing

Bobbin 27091.2 (R2) Freespan Foreign Object Wear Detection of foreign object

Bobbin Detection wear with part present and

(Pait Not Present) detection of foreign objects

+Point™ Sizing

FDB wear (drilled

+PointTM 96910.1 (RI I) suppmts)

+Point™ Detection Broached TSP wear

Sizing of foreign object +Point™ Sizing

wear when part is present -~

+PointTM l 0908.4 (RI) AVB wear Sizing of foreign object +PointTM Detection

wear when part is present +PointTM Sizing Detection of foreign

27901.1 (Rl) objects based on material and proximity of foreign

27902.1 (R2) Foreign Object Wear at object to the tube, per 27903.l (Rl) Freespan, TSP, and Expansion EPRl reports 1020631 and

+Point™ Detection +Poi.ntTM 27904.1 (R2) Transition. 1018561 ai1d SGMP-IL-27905 . l (R2) Morphology Dependent 16-01.

+Point™ Si.zing

27906.1 (R 1) (Part Not Present) 27907.1 (R2) Sizing of foreign object

wear (when part is present) per EPRI Repo1t 1020631.

11956.3 (R2) Drilled FOB Wear Array Detection

Array Broached TSP Wear Bobbin and/or 11956.4 (R2) +Poinfl'M Sizing

17901.1 RO (Axial) J 7901.3 RO (Circ.) 17902.1 RO (Axial) 17902.3 RO (Circ.) 17903.1 RO (Axial)

Freespan Volumetric Wear Array 17903.3 RO (Circ.)

Morphology Dependent (Part 17904.1 RO (Axial)

Not Present) 17904.3 RO (Circ.) 17905.1 RO (Axial) 17905.3 RO (Circ.) 17906.1 RO (Axial) 17906.3 RO (Circ.)

Serial No. 19-200 Enclosure: Page 5 of 9

Volumetric degradation at ITS, support structures,

and freespan with or without pait present.

Detection of foreign objects based on material and prox imity of foreign

object to the tube, per EPRI reports I 020631 and 1018561 and SGMP-IL-

16-01. Volumetric degradation at ITS, suppo1t structures,

and freespan with or without part present.

Detection of foreign Array Detection objects based on material +Point™ Sizing and proximity of foreign

object to the tube, per EPRI reports 1020631 and

1018561 and SGMP-IL-16-0 I.

5.0 Location, Orientation (if linear), and Measured Sizes (if available) of Service Induced Indications

Tables 5-1, 5-2, 5-3, and 5-4 provide the location and measured sizes of service induced indications relative to each degradation mechanism. The majority of the indications were from tube support plate wear.

Table 5-1: A VB Wear SG Row Col Volts Deg %TW Location Leg A 19 140 0.18 81 11 AV7 +0.25 HOT A 26 139 0.17 91 10 AV7 +0.79 HOT A 26 139 0.13 137 8 AV2-0.79 HOT C 26 3 0.15 115 6 AV2-0.56 COLD

Table 5-2: TSP Wear SG Row Col Volts Deg %TW Location Leg A 1 10 0.48 113 25 05C -0.09 COLD A 1 10 0.24 89 16 04C -0.12 COLD A 1 10 0.27 108 18 06C -0.69 COLD A 1 16 0.1 66 11 osc -0 .67 COLD A 1 58 0.1 112 10 03C -0.67 COLD A 1 60 0.28 105 20 03C +0.46 COLD A 1 60 0.11 137 10 03C -0 .55 COLD A 1 66 0.17 100 16 03C +0.40 COLD A 1 78 0.17 105 16 06C -0.07 COLD A 1 82 0.12 121 13 03C -0.58 COLD

A I 88 0.22 A 2 I 0.21 A 2 5 0.12 A 2 59 0.15 A 2 77 0.62 A 2 77 0.13 A 2 77 0.97 A 2 77 0.24 A 2 79 0.17 A 2 87 0.16 A 3 66 0.17 A 3 108 0.17 A 4 81 0.1 A 4 99 0.12 A 4 103 0.11 A 4 103 0.08 A 6 1 0.12 A 6 93 0.15 A 8 131 0.1 A 17 2 0.18 A 67 24 0.15 A 77 122 0.15 A 91 28 0.14 A 115 62 0.15 B 1 2 0.18 B l 2 0.19 B 1 2 0.15 B 1 2 0.08 B l 14 0.22 B 1 28 0.12 B I 28 0.18 B I 140 0.14 B l 140 0.12 B 2 17 0.11 B 2 31 0.15 B 2 31 0.21

B 2 61 0.15 B 2 111 0.16 B 2 113 0.22 B 2 113 0.21 B 3 46 0.19 B 3 46 0.31 B 3 54 0.15 B 3 76 0.09 B 3 80 0.15 B 3 84 0.21 B 3 88 0.18 B 3 90 0.11 B 3 112 0.14

112 19 121 19 101 13 88 15 112 31 33 12 114 35 90 16 95 16 73 15 105 16 132 16 103 11 62 13 51 12 18 9 43 12 122 15 66 11 95 15 72 13 105 13 80 11 101 12 66 15 150 15 81 13 158 7 103 14 114 10 145 14 67 12 154 10 44 9 117 13 108 16 77 12 103 14 115 17 91 16 109 15 100 21 123 13 76 9 113 14 102 17 107 16 83 11 133 13

Serial No. 19-200 Enclosure: Page 6 of 9

07C -0.07 COLD 07C -0.67 COLD 05C -0 .60 COLD 07C -0.30 COLD 08H -0.50 HOT 08H +0.40 HOT 07C -0.07 COLD 08C -0.09 COLD 07C -0 .14 COLD 07C +0.05 COLD 08C-0.21 COLD 05C + 0.37 COLD 07C +0.42 COLD 05C +0.42 COLD 05C +0.38 COLD 05C -0.61 COLD 04C-0.58 COLD 05C +0.23 COLD 06C +0.44 COLD 05C +0.46 HOT 07C +0.48 HOT 07C +0.44 HOT 07C -0.65 COLD 09H +0.47 COLD 06C +0.39 COLD 06C -0.65 COLD 05C +0.35 COLD 05C -0.62 COLD 07H-0.57 HOT 07H +0.44 HOT 07H-0.64 HOT 06C +0.39 COLD 06C-0.69 COLD 07H +0.41 HOT 06C +0.42 COLD 05C + 0.39 COLD 04C-0.60 COLD 07C + 0.42 COLD 07C +0.48 COLD 06C + 0.39 COLD 08C -0.42 COLD 07C -0.48 COLD 06C +0.48 COLD 07C -0.58 COLD 06C +0.37 COLD 07C +0.41 COLD 07C -0.51 COLD 07C +0.41 COLD 07C +0.46 COLD

B 4 117 0.08 B 5 84 0.15 B 5 88 0.11 B 5 88 0.26 B 5 88 0.16 B 5 88 0.12 B 5 88 0.14 B 5 90 0.18 B 5 90 0.18 B 5 116 0.2 B 6 75 0.16 B 6 125 0.09 B 10 121 0.09 B 10 121 0.09 B 20 139 0.14 B 34 9 0.14 B 39 120 0.1 B 45 12 0.1 B 54 121 0.18 B 56 11 0.13 B 64 13 0.15 B 69 126 0.12 B 94 45 0.07 B 95 110 0.09 B 99 44 0.1 B 99 106 0.14 B 108 47 0.13 B 108 47 0.1 B 108 63 0.1 B 110 89 0.09 B 114 75 0.1 B 115 74 0.19 C 1 4 0.14 C 1 8 0.23 C 1 16 0.15 C 1 16 0.14 C 1 82 0.13 C 1 94 0.3 C 1 112 0.22 C 1 112 0.27 C 2 137 0.14 C 5 52 0.25 C 6 25 0.15 C 6 25 0.16 C 6 107 0.07 C 7 54 0.23 C 25 36 0.22 C 30 137 0.14 C 48 15 0.13

82 8 159 12 104 10 80 19 80 13

131 11 89 12 97 14 104 14 111 15 50 13 105 9 81 8 54 8 88 11 76 11 128 8 112 10 98 13 71 12 133 14 122 11 159 6 127 9 149 8 76 11 123 10 140 8 328 10 50 9 99 8 109 14 89 9 88 13 67 8 53 8 92 8 126 16 120 11 89 14 -52 8 96 12 67 8 49 8 54 4 131 12 108 12 135 8 51 8

Serial No. 19-200 Enclosure: Page 7 of 9

07C +0.46 COLD 07C +0.45 HOT 05C -0.43 HOT 07C -0.43 HOT 07C +0.55 HOT 08C -0.43 HOT 08C +0.50 HOT 07C +0.48 HOT 08C +0 .50 HOT 07C +0.57 HOT 07C -0.45 HOT 05C +0.49 COLD 08C -0.50 HOT 08C +0.57 HOT 031-I-0.62 HOT 06C +0.46 HOT 08C +0.50 HOT 031-I-0.44 COLD 07C -0.53 HOT 03H-0.53 COLD 07C +0.21 COLD 07C +0.30 COLD 09C +0.45 HOT 08C-0.72 COLD 09C +0.46 HOT 07C -0.58 HOT 07H +0.32 HOT 07H-0.74 HOT 08C +0.35 COLD 08C -0.67 COLD 04H +0.41 HOT 06H +0.34 HOT 06C +0.39 COLD 07C +0.39 COLD 06C -0 .58 COLD 06C +0.44 COLD 08H +0.48 HOT 06H +0.48 HOT 06C +0.44 COLD 06C -0.60 COLD 08C +0.38 COLD 06C -0.48 COLD 07C +0.44 COLD 07C -0.57 COLD 05C -0.55 COLD 06C-0.62 COLD 07C +0.46 COLD 08C +0.32 COLD 08C +0.34 COLD

C 52 19 0.11 119 C 83 116 0.23 140 C 104 55 0.57 148 C 104 67 0.2 60 C 110 73 0.37 125 C 114 83 0.16 117

Table 5-3: FDB Wear SG Row Col Volts Deg C 32 89 0.32 147 C 34 91 0.18 148 C 35 92 0.54 114

a e - : T bl 5 4 F ore 1gn Ob' tW 1.1ec SG Row Col Volts Deg A 25 72 0.32 87 A 110 77 0.21 252 B 91 88 0.34 68 B 92 87 0.14 77

6.0 Tubes Plugged during the Inspection Outage

6 12 22 10 17 9

%TW 15 10 22

ear %TW

45 7

43 30

Serial No. 19-200 Enclosure: Page 8 of 9

08C +0.46 COLD 07C -0.69 COLD 08C +0.35 COLD 08C -0.57 COLD 08C +0.28 COLD 09H +0.44 COLD

Location Leg BPH +0.48 COLD BPH +0.46 COLD BPH +0.46 COLD

Location Leg TSH +0.53 HOT BPH +0.32 HOT TSH +0.16 HOT TSH +0.16 HOT

During RF-24, ten (10) tubes total were removed from service, by plugging. Three (3) tubes were plugged due to foreign object wear. The remaining seven (7) tubes were plugged due to possible loose parts (PLPs). Table 6-1 identifies RF-24 tube plugging.

T bl 6 1 RF 24 T b Pl a e - : - u e U{!Q]ng

Tube Degradation Steam Generator

A B C Foreign Object Wear 2 1 0 Possible Loose Part 5 0 2

RF-24 Tubes 7 1 2

Plue:ged

7.0 Number and Percentage of Tubes Plugged to Date

A total of eighteen (18) tubes have been plugged in all three of the VC Summer Steam Generators as shown in Table 7-1. Each steam generator has a total of 6307 tubes.

a e - : T bl 7 1 VC S ummer e a - um ero u es D It 75 N b f T b Pl U1!1!e d Outage Steam Generator

A B C PSI (1994) 0 1 2

RF-12 (Fall 2000) 3 0 2 RF-24 (Fall 2018) 7 1 2

Total Tubes Pluge:ed 10 2 6 Total Percentage 0.159% 0.032% 0.095%

Serial No. 19-200 Enclosure: Page 9 of 9

8.0 Results of Condition Monitoring, including the results of Tube Pulls and In-Situ Testing

All degradation identified during RF-24 inspection satisfied condition monitoring requirements for SG tube structural and leakage integrity. Therefore, tube pulls and in-situ pressure testing were not necessary.

9.0 References

9.1 YC Summer I RF24 Steam Generator Degradation Assessment (Post-Outage Revision) 9.2 VC Summer I RJ-'24 Condition Monitoring and Operational Assessment 9.3 YC Summer I RF24 Steam Generator Eddy Current Final Report