ML13284A065

End of Cycle 15 Steam Generator Tube Inspection Report

ML13284A065
Person / Time
Site:	Millstone
Issue date:	10/02/2013
From:	Scace S Dominion, Dominion Nuclear Connecticut
To:	Document Control Desk, Office of Nuclear Reactor Regulation
Shared Package
ml13284a065	List: ML13284A065
References
Download: ML13284A065 (18)

Text

Dominion Nuclear Connecticut, Inc.i __Di Millstone Power Station Rope Ferry Road Waterford, CT 06385 OCT 0 2 2013 U.S. Nuclear Regulatory Commission Serial No.13-500 Attention: Document Control Desk NSS&L/MLC RO Washington, DC 20555 Docket No. 50-423 License No. NPF-49 DOMINION NUCLEAR CONNECTICUT, INC.

MILLSTONE POWER STATION UNIT 3 END OF CYCLE 15 STEAM GENERATOR TUBE INSPECTION REPORT In accordance with the Millstone Power Station Unit 3 Technical Specification (TS)

Section 6.9.1.7, Dominion Nuclear Connecticut, Inc. hereby submits the End of Cycle 15 (EOC15) Steam Generator (SG) Tube Inspection report. The report is submitted within 180 days after initial entry into MODE 4 following completion of the spring 2013 SG inspections performed in accordance with TS 6.8.4.g, "Steam Generator (SG) Program."

Initial entry into Mode 4 occurred on May 15, 2013.

Enclosure 1 contains the EOC15 SG Tube Inspection report. Enclosure 2 contains a list of acronyms.

The report includes the following:

a. The scope of inspections performed on each SG,

b. Degradation mechanisms found,

c. Nondestructive examination techniques utilized for each degradation mechanism,

d. Location, orientation (if linear), and measured sizes (if available) of service induced indications,

e. Number of tubes plugged during the inspection outage for each degradation mechanism,

f. The number and percentage of tubes plugged to date and the effective plugging percentage in each steam generator,

g. The results of condition monitoring, including the results of tube pulls and in-situ testing,

h. 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,

i. The calculated accident induced leakage rate from the portion of the tubes below 15.2 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; and

Serial No.13-500 Docket No. 50-423 Page 2 of 2

j. The results of monitoring for tube axial displacement (slippage). If slippage is discovered, the implications of the discovery and corrective action shall be provided.

If you have any questions or require additional information, please contact Mr. William D.

Bartron at (860) 444-4301.

Sincerely, S. . S~cac President- Millstone

Enclosures:

1) Millstone Power Station Unit 3, End of Cycle 15 Steam Generator Tube Inspection Report

2) Acronyms Commitments made in this letter: None cc: U.S. Nuclear Regulatory Commission Region I 2100 Renaissance Blvd, Suite 100 King of Prussia, PA 19406-2713 J. S. Kim NRC Project Manager U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 08-C2A 11555 Rockville Pike Rockville, MD 20852-2738 NRC Senior Resident Inspector Millstone Power Station

Serial No.13-500 Docket No. 50-423 ENCLOSURE I MILLSTONE POWER STATION UNIT 3 END OF CYCLE 15 STEAM GENERATOR TUBE INSPECTION REPORT MILLSTONE POWER STATION UNIT 3 DOMINION NUCLEAR CONNECTICUT, INC.

Serial No.13-500 Docket No. 50-423 Enclosure 1, Page 1 of 13 End of Cycle 15 Steam Generator Tube Inspection Report In accordance with Millstone Power Station Unit 3 (MPS3) Technical Specification (TS) Section 6.9.1.7, Dominion Nuclear Connecticut, Inc. (DNC) hereby submits the End of Cycle 15 (EOC15) Steam Generator (SG) Tube Inspection report. The report is submitted within 180 days after initial entry into MODE 4 following completion of the spring 2013 (i.e., 3R15) SG inspections performed in accordance with TS 6.8.4.g, "Steam Generator (SG) Program." Initial entry into Mode 4 occurred on May 15, 2013; therefore, this report is required to be submitted by November 11,2013.

This enclosure provides specific responses to TS 6.9.1.7 report requirements for the SG inspections performed during 3R1 5. Enclosure 2 contains a list of acronyms.

Introduction MPS3 is a four loop Westinghouse pressurized water reactor with Westinghouse Model F SGs.

Each SG contains 5626 U-bend thermally treated Inconel 600 tubes. The tubing is nominally 0.688 inches outside diameter with a 0.040 inch nominal wall thickness. During SG fabrication, the tubes were hydraulically expanded over the full depth of the 21.23 inch thick tubesheet. The tubesheet was drilled on a square pitch with 0.98 inch spacing. There are 59 rows and 122 columns in each SG. The radius of the row 1 U-bends is 2.20 inches. The U-bends in rows 1 through 10 were stress relieved after being formed. Secondary side tube support structures include a flow distribution baffle, seven plate supports with broached holes on the vertical section of the tubes, and six anti-vibration bars (AVBs) on the U-bend section of the tubes. See Figure 1, "Millstone Power Station Unit 3 Steam Generator Arrangement," for illustration of SG component locations.

The SGs have accrued 20.7 effective full power years (EFPYs) of operation as of the EOC15 (April 2013). MPS3, which is a 1296 megawatt electric unit, operates with a hot leg temperature of 620 degrees Fahrenheit.

EOC15 SG Tube Inspection Report This section provides responses to each of the requirements specified by MPS3 TS 6.9.1.7.

Bolded text represents TS verbiage. The required information is provided immediately following the restatement of each reporting requirement.

A report shall be submitted within 180 days after the initial entry into MODE 4 following completion of an inspection performed in accordance with TS 6.8.4.g, Steam Generator (SG) Program. The report shall include:

a. The scope of inspections performed on each SG, One hundred percent of the operational tubes within SG B and SG D, a total of 11,146 tubes or approximately 50 percent of the total population of tubes, were inspected full length. The majority of the tubing length was examined with bobbin probes. The U-bends of row 1 and row 2 tubes (483 in-service tubes) were examined by a Motorized Rotating Probe Coil (MRPC) technique in addition to the bobbin probe examination of the straight legs of the tubes. An additional augmented sample of 617 tube locations was examined with a MRPC probe. The

Serial No.13-500 Docket No. 50-423 Enclosure 1, Page 2 of 13 augmented sample inspections were performed in areas of special interest including hot leg expansion transitions, tube overexpansion locations within the hot leg tubesheet, and dents, as well as locations where the bobbin probe response was ambiguous. The sample included bounding examinations for Possible Loose Part (PLP) indications and new volumetric flaw (fabrication or foreign object wear) detections. An augmented sample of 12,610 tube locations was inspected with an array coil probe. The array probe sample included 100% of the hot-leg Top-of-Tubesheet (TTS) locations (11,146 tubes), and approximately 13% of the cold-leg TTS locations (1,464 tubes). The extent of the TTS examinations was from the first support structure detected above the secondary face of the tubesheet to 15.2 inches below the secondary face of the tubesheet.

Secondary side activities were performed in SG B, SG C, and SG D during 3R15 and included the following:

" High pressure sludge lancing and Upper Bundle Flush (UBF).

" Post-sludge lancing visual examination of TTS annulus and no-tube lane to: assess as-left material condition and cleanliness and identify and remove any retrievable foreign objects.

" Visual investigation of accessible locations having eddy current testing (ECT) indications potentially related to foreign objects, and, if present, removal of those retrievable foreign objects.

" Secondary side upper internal examinations within SG C only as follows:

Steam drum visual inspections to evaluate the material condition and cleanliness of key components such as moisture separators, drain systems, and interior surfaces.

Drop down examinations (through the primary separators) of the upper tube bundle and AVB supports.

Visual inspections of feed ring internal interface for flow assisted corrosion.

Visual inspections of upper Tube Support Plate (TSP) to assess material conditions and cleanliness.

b. Degradation mechanisms found, The existing degradation mechanisms found during 3R15 included AVB wear, TSP wear, volumetric indications from fabrication and volumetric degradation from foreign object wear. A summary of the ECT results from 3R1 5 are provided in Table 1.

c. Nondestructive examination techniques utilized for each degradation mechanism, Table 2 identifies the examination techniques used for each identified degradation mechanism.

d. Location, orientation (if linear), and measured sizes (if available) of service induced indications, Tables 3 through 8 identify AVB wear and non-AVB wear volumetric indications reported during 3R15.

Serial No.13-500 Docket No. 50-423 Enclosure 1, Page 3 of 13

e. Number of tubes plugged during the inspection outage for each degradation mechanism, The number of tubes plugged by degradation mechanisms is summarized below. During 3R15, 10 tubes were removed from service; five from SG B and five from SG D.

Two tubes (one in each SG) with indications indicative of TSP wear sized at greater than or equal to 40% through wall (TW), were plugged.

Seven tubes (four tubes in SG B and three tubes in SG D), were plugged discretionarily due to signals indicative of TSP wear sized less than 40% TW but greater than 15% TW. All tubes reported to have TSP wear 15% or greater were removed from service by plugging.

One tube in SG D, (row 1, column 50), was discretionarily removed from service due to a reported restriction in the U-bend. Historically, the U-bend portion of this tube has taken several attempts to acquire acceptable rotating coil data. Although examination of this tube was ultimately successful, and the examination revealed no evidence of degradation, this tube was preventatively plugged in order to improve the efficiency of future examinations in this SG.

Number of Tubes Plugged by Degradation Mechanism During 3R15 DEGRADATION SG A SG B SG C SG D TSP Wear >_40%TW 0 1 0 1 TSP Wear < 40%TW 0 4 0 3 (discretionary)

Restricted Tube 0 0 0 1

f. The number and percentage of tubes plugged to date and the effective plugging percentage in each steam generator, The total number of tubes plugged to date and the effective plugging percentage in each SG is summarized below.

Number and Percentage of Tubes Plugged To Date SG A SG B SG C SG D Prior to 3R15 49 20 22 86 During 3R15 0 5 0 5 Total After 3R1 5 49 25 22 91 Percentage 0.871 0.444 0.391 1.617 Overall Percentage 0.831 Since no sleeving has been performed in the MPS3 SGs, the effective plugging percentage is the same as the actual plugging percentage.

Serial No.13-500 Docket No. 50-423 Enclosure 1, Page 4 of 13

g. The results of condition monitoring, including the results of tube pulls and in-situ

testing, No tubes were pulled and no in-situ pressure tests were performed. The condition monitoring assessment concluded that the structural integrity, operational leakage and accident induced leakage performance criteria were not exceeded during the operating interval preceding 3R1 5.

h. 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, No primary to secondary SG leakage was reported during Cycle 15.

i. The calculated accident induced leakage rate from the portion of the tubes below 15.2 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; and For the purposes of condition monitoring assessment, and in accordance with the permanent alternate repair criteria (License Amendment 255, ADAMS Accession No. ML12299A498), the accident leakage attributed to degradation within the tubesheet below the H* dimension must be estimated by applying a factor of 2.49 to the operational leakage. There was no recordable operational leakage during Cycle 15; hence, the leakage from this degradation during a limiting accident would have been zero (i.e., 2.49 x 0).

j. The results of monitoring for tube axial displacement (slippage). If slippage is discovered, the implications of the discovery and corrective action shall be provided.

The tube slippage monitoring was performed on SG B and SG D using the bobbin coil data during 3R15. There was no detection of slippage identified during 3R15.

Serial No.13-500 Docket No. 50-423 Enclosure 1, Page 5 of 13 Table 1 ECT Summary for 3R15 SG A SG B SG C SG D Total Number of Tubes Inservice at Start of 3R1 5 5,577 5,606 5,604 5,540 22,327 Number of Tubes Inspected F/L w/Bobbin Probe N/A 4,999 N/A 4,936 9,935 Number of Tubes Inspected w/Bobbin Probe Hot Leg N/A 363 N/A 365 728 Straights and Cold Leg Candy Canes (Rows 3 through 5)

Number of Tubes Inspected w/Bobbin Probe Hot and Cold N/A 244 N/A 239 483 Leg Straights and MRPC U-Bends (Rows 1 and 2)

Previously Plugged Tubes 49 20 22 86 177 Number of Tubes Incomplete w/Bobbin Probe due to N/A 0 N/A 0 0 Obstruction Number of Examinations w/MRPC (Total)T N/A 548 N/A 552 1,100

• Row 1 and 2 U-Bends N/A 244 N/A 239 483 9Hot Leg Misc. Special Interest - Diagnostic Exams and N/A 155 N/A 178 333 from Previous History

• Cold Leg Misc. Special Interest - Diagnostic Exams N/A 26 N/A 22 48 and from Previous History

• U-bend. Special Interest - Diagnostic Exams and from N/A 17 N/A 22 39 Previous History oOther Extent-Based Exams (e.g. bounding, 10% HL N/A 106 N/A 91 197 OXP)

Number of Examinations w/Array (Total) N/A 6,338 N/A 6,272 12,610

• Hot Leg Tubesheet (01 H/02H to TSH - 15.2")* N/A 5,606 N/A 5,540 11,146 oCold Leg Tubesheet (01C/02C to TSC - -15.2")* N/A 732 N/A 732 1,464

• Foreign Object Wear Bounding N/A 0 N/A 0 0 Hot Leg OXP/OVR Array Exam Sample Size** N/A 100% N/A 100% N/A Cold Leg OXP/OVR Array Exam Sample Size** N/A 20% N/A 20% N/A Tubes w/ Max AVB Wear > 37% N/A 0 N/A 0 0 Tubes w/ Max AVB Wear > 20% but < 37% N/A 15 N/A 21 36 Tubes w/ Max AVB Wear < 20% N/A 35 N/A 67 102 Tubes w/ Max TSP Wear > 40% N/A 1 N/A 1 2 Tubes w/ Max TSP Wear > 20% but < 40% N/A 3 N/A 4 7 Tubes w/ Max TSP Wear < 20% N/A 7 N/A 2 9 Tubes w/ Max Non-Structure Vol. Deg. > 40% N/A 0 N/A 0 0 Tubes w/ Max Non-Structure Vol. Deg. > 20% but < 40% N/A 3 N/A 5 8 Tubes w/ Max Non-Structure Vol. Deg. < 20% N/A 1 N/A 1 2 Total Tubes Plugged as a Result of this Inspection: N/A 5 N/A 5 10 e Due to TSP Wear > 40% N/A 1 N/A 1 2 9 Due to TSP Wear < 40% (discretionary) N/A 4 N/A 3 7 o Due to AVB Wear N/A 0 N/A 0 0 e Due to Non-Support Volumetric Degradation N/A 0 N/A 0 0 e Due to a U-bend restriction (discretionary) N/A 0 N/A 1 1 4 Values provided in the total and the sub-bullets correspond to the number of examinations performed.

• Within the cutout region, the upper extent of the array probe exam was the second support (i.e., 02H or 02C).

• • Percent sample is based on the number of OXP/OVRs located within the upper 15.2 inches of tubesheet expansion.

Serial No.13-500 Docket No. 50-423 Enclosure 1, Page 6 of 13 Table 2 Degradation Mechanisms and Inspection Techniques Degradation Classification Mechanism Location Probe Type Existing Tube Wear Anti-Vibration Bars Bobbin - Detection and Sizing Existing Tube Wear Tube Support Plate Bobbin

+PointTM- Detection

- Sizing M

T Tube Wear Bobbin, Array and +Point Existing (foreign objects) Freespan and TTS Detection

+PointTM- Sizing Existing IGA/SCC Tube Ends N/A*

Existing FAC Feed Ring and J Tube to Feed Ring Visual Inspection Interface Existing Tube Wear Flow Distribution Baffle Bobbin - Detection

+Point TM - Sizing ODSCC Hot Leg Top-of-Tubesheet Array - Detection Potential PWSCC and Sludge Region +PointTM - Detection and Sizing ODSCC Bulges, Dents, Manufacturing Array - Detection Potential PWSCC Anomalies, and Above-Tubesheet +PointTM- Detection and Sizing Overexpansions (OVR)

Potential PWSCC Tubesheet Array - Detection Overexpansions (OXP) +PointTM- Detection and Sizing Potential ODSCC Row 1 and 2 U-bends +PointTM - Detection and Sizing PWSCCRo1an2U-ed-Potential FAC Moisture Separators Visual Inspection Potential Plug Installation Plugs Visual Inspection Problems Potential Tube Slippage Within Tubesheet Bobbin Detection

• Inspection for this mechanism was not necessary under the permanent alternate repair criteria implemented during 3R15.

Serial No.13-500 Docket No. 50-423 Enclosure 1, Page 7 of 13 Table 3 3R15 Steam Generator B Volumetric Degradation Summary (excludes AVB Wear)

Axial Circ. Maximum Plugged Row Col Location Length Length Depth Cause Existed in History or New (YesPNo)

(in) (in) (%TW) (YesNo) 1 37 03C+0.33" 0.30 0.42 11 TSP Wear Signal first present in 3R1 1 No 2 93 05C-0.64" 0.30 0.33 33 TSP Wear New Yes 15 99 03H-0.62" 0.32 0.45 14 TSP Wear New No 22 80 08C-0.99" 0.33 0.37 47 TSP Wear New Yes 27 92 05H-0.71" 0.32 0.31 18 TSP Wear Signal first present in 3R13 Yes 27 93 05H-0.63" 0.32 0.34 30 TSP Wear New Yes 05H-0.64" 0.24 0.32 11 TSP Wear New 29 65 08C-0.91" 0.30 0.35 12 TSP Wear New No 30 52 05H-0.60" 0.32 0.41 13 TSP Wear Signal first present in 3R1 3 No 31 67 08C-0.98" 0.33 0.42 24 TSP Wear New Yes 32 30 06H-0.91" 0.29 0.41 12 TSP Wear New No 33 49 01H-0.02" 0.21 0.34 5 TSP Wear New No 1 119 TSC+3.87" 0.27 0.37 23 Foreign Object Signal first present in 3R13. No No Wear loose part currently present.

1 120 TSC+3.83" 0.30 0.33 20 Foreign Object Signal first present in 3R13. No No Wear loose part currently present.

1 121 TSC+6.54" 0.65 0.39 8 Foreign Object Signal first present in 3R13. No No I_ III _ IWear loose part currently present.

44 98 02H+15.99" 0.29 0.34 30 Fabrication Fabrication No

Serial No.13-500 Docket No. 50-423 Enclosure 1, Page 8 of 13 Table 4 3R15 Steam Generator D Volumetric Degradation Summary (excludes AVB wear)

Axial Circ. Maximum Row Col Location Length Length Depth. Cause Existed in History or New Plugged (in) (in) (%TW) (Yes/No) 24 89 06C-0.74" 0.30 0.33 7 TSP Wear New No 26 98 08C-0.94" 0.33 0.42 27 TSP Wear New Yes 27 39 08C-0.90" 0.27 0.31 13 TSP Wear Signal first present in 3R9 No 35 73 04H-0.48" 0.30 0.37 21 TSP Wear Signal first present in 3R13 No 41 56 06H-0.83" 0.33 0.39 24 TSP Wear New Yes 44 85 08C-0.90" 0.36 0.39 23 TSP Wear New Yes 44 89 08C-0.62" 0.33 0.39 45 TSP Wear New Yes 46 99 01H+0.51" 0.33 0.37 25 Foreign Object Wear loosefirst Signal partpresent in 3R1 currently 1. No present. No 52 42 01H+0.57" 0.39 0.41 25 Foreign Object Signal first present in 3R13. No No

__________Wear loose part currently present.

52 91 01H+2.47" 0.33 0.41 32 Foreign Object Signal first present inpresent.

3R9. No No Wear loose part currently 58 50 01C+0.42" 0.22 0.27 16 Foreign Object Signal first present in 3R13. No No Wear loose part currently present.

58 51 01C+0.55" 0.33 0.44 26 Foreign Object Signal first present in 3R13. No No Wear loose part currently present.

04C-1.50" 0.21 0.37 22 Fabrication Fabrication No 38 20 04C-2.14" 0.51 0.37 23 Fabrication Fabrication No 04C-2.86" 0.27 0.33 21 Fabrication Fabrication No

Serial No.13-500 Docket No. 50-423 Enclosure 1, Page 9 of 13 Table 5 3R15 Steam Generator B AVB Wear Listings, Repeat Indications Row Col AVB %TW Row Col AVB %TW 30 12 2 12 41 50 4 23 30 12 5 15 41 69 4 22 32 108 4 16 41 69 5 34 33 12 2 15 41 77 3 16 33 12 5 16 41 77 4 16 33 39 3 9 41 77 5 23 33 109 2 17 42 19 1 10 33 109 3 19 42 21 2 17 34 18 3 8 42 21 3 13 34 18 4 10 42 21 4 23 34 109 2 10 42 21 5 28 34 109 3 24 42 21 6 15 34 109 5 16 42 33 2 14 34 109 6 11 42 96 2 25 34 110 3 13 42 96 3 14 35 103 6 10 42 96 4 15 35 106 3 9 42 96 5 14 35 106 4 16 42 98 2 31 35 106 6 10 42 98 3 28 36 22 6 11 42 98 5 7 36 39 2 11 43 86 4 15 36 39 3 14 43 100 3 25 36 39 5 19 43 100 4 29 36 39 6 15 43 100 6 12 36 67 6 10 45 22 6 11 37 100 4 11 46 99 4 11 37 103 2 11 48 25 6 8 37 104 3 13 49 27 5 12 37 104 4 11 50 72 3 13 38 104 3 16 50 88 2 19 38 104 4 26 50 88 3 22 38 104 5 12 50 88 4 17 39 30 2 13 50 88 5 13 39 30 4 12 50 88 6 10 39 30 5 13 51 91 4 16 39 96 3 13 51 91 5 21 40 23 2 14 54 35 4 10 40 23 3 11 54 35 5 14 40 23 4 15 54 35 6 10 40 23 5 16 54 36 5 33 40 24 3 16 54 36 6 17 40 24 4 20 54 45 2 10 40 24 5 13 56 41 3 11 41 34 2 15 56 42 6 12 41 34 3 16 56 81 1 9 41 34 4 33 57 70 2 11 41 34 5 31 58 75 5 22 41 34 6 13 59 65 2 13 41 50 3 14

Serial No.13-500 Docket No. 50-423 Enclosure 1, Page 10 of 13 Table 6 3R15 Steam Generator B AVB Wear Listings, New Indications Row Col AVB %TW 33 109 6 10 41 69 3 11 49 27 1 12 49 27 2 10 50 29 2 18 50 29 6 12 51 91 6 14 54 35 2 13 56 71 2 10

Serial No.13-500 Docket No. 50-423 Enclosure 1, Page 11 of 13 Table 7 3R15 Steam- Generator D AVB Wear Listings, Repeat Indications Row Col. AVB %TW Row Col A"B %TW Row Col A"B <%TW`

9 121 6 11 40 101 3 13 47 98 5 12 24 117 2 20 40 102 3 13 48 25 6 13 25 115 2 9 40 102 4 27 48 96 5 19 26 8 6 16 40 102 5 19 49 62 1 20 27 115 2 18 40 103 1 13 49 62 2 22 27 115 5 15 40 103 2 25 49 62 3 29 28 8 1 14 40 103 3 29 49 62 4 18 28 8 6 17 40 103 4 35 49 66 1 14 28 114 2 29 40 103 5 33 49 66 2 31 28 114 5 11 40 103 6 19 49 66 3 16 29 113 2 17 41 26 2 17 49 67 2 24 29 113 5 15 41 26 5 33 49 67 3 22 30 113 2 14 41 26 6 34 49 69 2 10 30 114 1 12 41 30 2 10 49 70 2 12 30 114 6 23 41 30 3 14 49 95 2 19 33 109 5 20 41 30 4 23 49 95 3 18 34 109 2 12 41 30 5 18 49 95 4 17 35 99 2 14 41 31 2 13 50 80 2 10 35 102 5 17 41 39 2 19 50 80 3 13 35 103 5 19 41 39 3 22 50 83 2 20 35 108 3 17 41 39 4 25 51 89 6 15 35 108 4 14 41 39 5 27 52 33 5 11 35 109 4 17 41 39 6 11 52 67 4 17 36 97 2 12 41 78 2 9 52 67 5 12 37 93 2 13 41 78 3 20 52 69 2 13 37 93 3 17 41 78 4 18 52 87 5 16 37 101 2 18 41 78 5 14 52 88 1 12 37 101 3 16 41 87 3 8 52 88 2 14 37 101 4 14 41 90 1 12 52 88 4 20 37 103 2 13 41 90 3 12 53 35 4 14 37 103 5 14 42 103 2 15 53 35 5 19 37 106 1 14 43 20 6 11 53 35 6 16 37 106 3 21 43 25 5 14 53 70 2 14 37 106 4 34 43 33 3 11 54 49 2 17 37 106 5 26 43 95 4 11 54 49 3 25 37 106 6 15 43 95 5 16 54 49 4 11 38 21 5 13 43 100 4 20 55 40 6 20 38 98 2 13 43 100 5 10 55 75 6 18 38 98 4 16 43 100 6 13 55 84 5 25 40 99 2 15 43 102 5 12 56 43 1 12 40 99 4 29 43 102 6 13 58 59 11 11 40 99 5 33 44 21 1 12 40 100 4 15 45 41 3 19 40 100 5 14 45 96 2 12 40 100 6 15 45 96 3 13

Serial No.13-500 Docket No. 50-423 Enclosure 1, Page 12 of 13 Table 8 3R15 Steam Generator D AVB Wear Listings, New Indications Row Col AVB %TW 23 10 6 12 26 115 2 16 31 99 2 10 31 99 5 10 31 99 6 10 32 112 5 12 33 86 3 11 33 86 4 10 33 109 2 12 35 99 5 15 35 107 4 10 35 109 5 12 36 82 3 11 37 103 3 11 38 21 6 13 40 32 2 14 40 99 3 11 40 101 4 11 40 101 5 12 40 101 6 12 40 102 6 12 41 29 4 12 41 29 6 12 45 22 6 11 45 47 6 15 47 24 1 12 47 96 5 13 49 86 3 12 50 28 6 12 50 83 3 11 52 87 6 10 53 33 6 12 54 87 1 11 55 84 6 10

Serlel No.13-500 Docket No. 50-423 Enclosure 1, Page 13 of 13 Figure 1 STEAM GENERATOR ARRANGEMENT

[REDACTED]

Serial No.13-500 Docket No. 50-423 ENCLOSURE 2 Acronyms MILLSTONE POWER STATION UNIT 3 DOMINION NUCLEAR CONNECTICUT, INC.

Serial No.13-500 Docket No. 50-423 Enclosure 2, Page 1 of 1 Acronyms AVB Anti-Vibration Bar OVR Above Tubesheet Over Expansion BLG Bulge OXP Over Expansion C Column PID Positive Identification CL Cold Leg PLG Tube is plugged DDH Ding or Dent Signal - Reviewed in PLP Possible Loose Part History PTE Partial Tubesheet Expansion DDI Distorted Dent or Ding Indication PWR Pressurized Water Reactor DDS Ding or Dent Signal - Non- PWSCC Primary Water Stress Corrosion Confirming w/RPC Cracking DNG Ding R Row DNT Dent Indication RAD Retest Analyst Discretion ECT Eddy Current Test RBD Retest - Bad Data EFPY Effective Full Power Years RIC Retest - Incomplete EPRI Electric Power Research Institute RRT Retest - Restricted Tube ETSS Examination Technique S/N Signal-to-Noise Ratio Specification Sheet SAI Single Axial Indication F/L Full Length SCC Stress Corrosion Cracking FAC Flow Accelerated Corrosion SCI Single Circumferential Indication FDB Flow Distribution Baffle SG Steam Generator FO Foreign Object SLG Sludge FOTS Foreign Object Tracking System SSI Secondary Side Inspection HL Hot Leg SVI Single Volumetric Indication IGA Intergranular Attack TEC Tube End Cold-leg INF Indication Not Found TEH Tube End Hot-leg INR Indication Not Reportable TFH Tangential Flaw-Like Signal -

LPI Loose Part Indication Reviewed in History LPR Loose Part Removed TFS Tangential Flaw-Like Signal - Non-LPS Loose Part Signal Confirming w/RPC MRPC Motorized Rotating Pancake Coil TSC Top of Tubesheet Cold-leg NDD No Detectable Degradation TSH Top of Tubesheet Hot-leg NDE Nondestructive Examination TTS Top of Tubesheet NDF No Degradation Found TWD Through-Wall Depth NEI Nuclear Energy Institute %TW Percent Through-Wall NQH Non-quantifiable Indication - VOL Volumetric Indication Reviewed in History NQI Non-quantifiable Indication OA Operational Assessment ODSCC Outer Diameter Stress Corrosion Cracking