L-PI-16-030, Transmittal of 2015 180-Day Steam Generator Tube Inspection Report

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Transmittal of 2015 180-Day Steam Generator Tube Inspection Report
ML16141B250
Person / Time
Site: Prairie Island Xcel Energy icon.png
Issue date: 05/20/2016
From: Northard S
Northern States Power Co
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
L-PI-16-030
Download: ML16141B250 (19)
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Text

Prairie Island Nuclear Generating Plant Xcel Energy@ 1717 Wakonade Drive East Welch. MN 55089 MAY 2 0 2016 L-PI-16-030 TS 5.6.7 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Prairie Island Nuclear Generating Plant Unit 2 Docket 50-306 Renewed Facility Operating License No. DPR-60 2015 Unit 2 180-Day Steam Generator Tube Inspection Report In accordance with Prairie Island Nuclear Generating Plant, Unit 2, Technical Specification 5.6.7, "Steam Generator Tube Inspection Report," Northern States Power Company, a Minnesota corporation, doing business as Xcel Energy (hereafter "NSPM")

submits the enclosed report of steam generator tube inspections performed during the 2015 refueling and maintenance outage on Unit 2.

Summary of Commitments This letter contains no new commitment and no revision to an existing commitment.

Scott Northard Acting Site Vice President - Prairie Island Nuclear Generating Plant Northern States Power Company- Minnesota Enclosure (1) cc: Administrator, Region Ill, USNRC Project Manager, Prairie Island, USNRC Resident Inspector, Prairie Island, USNRC

Enclosure 1 Prairie Island Nuclear Generating Plant- Unit 2 2015 Steam Generator Tube Inspection Report

( 17 pages follow)

ENCLOSURE 1 Prairie Island Nuclear Generating Plant- Unit 2 2015 Steam Generator Tube Inspection Report In accordance with Prairie Island Nuclear Generating Plant (PINGP), Unit 2 Technical Specification 5.6.7, Xcel Energy Nuclear Department submits this report of steam generator tube inspections performed during the 2015 refueling and maintenance outage for Unit 2 (2R29).

PINGP Unit 2 has two Areva Model 56/19 Replacement Steam Generators (RSGs) with approximately 5,600 square meters of heat transfer area utilizing tubes with 19 millimeter outside diameter. Each RSG has 4,868 thermally-treated Alloy 690 u-tubes manufactured by Sandvik which have an outside diameter of 0. 750 inch and a nominal wall thickness of 0.043 inch. The tubes are configured in a square pitch of 1.0425 inches with 55 rows and 114 columns (see Figure 1). The tube u-bends vary in radius from 2.7000 inches for a row 1 tube to 58.9950 inches for a row 55 tube. The tubes vary in length from 738.16 inches for row 1 tubes to 923.04 inches for row 55 tubes. Row 1 through row 9 tubes were subject to stress relieving following the bending process using the thermal treatment process for an additional 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> minimum soak time. The tubes were hydraulically expanded at each end for the full depth of the tubesheet with the expansion transition being between 0.079 inches and 0.236 inches below the secondary tubesheet face.

The tubesheet is low alloy steel 21.46 inches thick with alloys 82 and 182 cladding 0.375" thick for an overall thickness of 21.835 inches. The tubes are supported by eight tube support plates (TSPs) and five anti-vibration bars (AVBs) intersecting tubes between 1, 3, 5, 7 and 9 times (see Figure 2). There is one straight bar that intersects all rows at the center of each bend, two 57 degree bars that intersect rows 13 through 55 and two 14 degree bars that intersect rows 25 through 55. In addition there are 24 peripheral tubes with nine staples (one at each AVB location) that carry the entire load of the complete AVB assembly. All TSPs are constructed from Type 410 stainless steel. The TSPs have a minimum thickness of 1.18 inch and have quatrefoil-shaped holes through which the tubes pass. The AVBs are constructed from Type 405 stainless steel and are rectangular in cross section (nominally 0.5 inch by 0.3 inch).

Each RSG is equipped with a Loose Parts Trapping Systems (LPTS), which is composed of screens at the top of the downcomer and at the top of the primary (cyclone) separators.

These screens (0.14" square mesh formed from 0.031" diameter wire), prevent foreign material from entering the steam generator tube area from the main feedwater and auxiliary feedwater systems (see Figure 2).

Page I of 17

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loose Parts Tra~~iH9 Systems

---UPPERMOST TSP Figure 2 The original Westinghouse Model 51 Steam Generators (SGs) were replaced during the 2013 refueling outage after 33.56 EFPY of operation. During the 2015 refueling outage the first in-service inspection (lSI) was conducted on the RSGs after accumulating the initial 1.66 EFPY of RSG operation.

Italicized text represents technical specification excerpts. Each excerpt is followed by the appropriate information intended to address each specific NOTE: requirement and also includes additional details based on benchmarking previous submittals and Staff requests for additional information of peer Licensees. A legend of codes and field names is included at the end of the report.

5. 6 Reporting Requirements
5. 6. 7 Steam Generator Tube Inspection Report A report shall be submitted within 180 days after initial entry into MODE 4 following completion of an inspection performed in accordance with the Specification 5. 5. 8, Steam Generator (SG) Program.

Initial entry into MODE 4 occurred on November 27, 2015, dictating submittal of this report on or before May 25, 2016.

The report shall include:

a. The scope of inspections performed on each SG, Table 1 and the notes that follow, provides the scope of inspections performed during 2R29.

Page 3 of 17

TABLE 1 SCOPE LEG EXTENT TECHNIQUE SG 21 SG22 Row 7 through 55CD H/C F/L X-ProberM 100%(4184) 100%(4184)

Row 3 through 6 H AV5TEH X-ProberM 100%(456) 100%(456)

Row 1 through 2 H 08HTEH X-ProberM 100%(228) 100%(228)

Row 1 through 2 H 08CTEH Bobbin N/A 100%(228)

Row 1 through 2 c 08HTEC Bobbin 100%(228) N/A Row 1 through 2 c 08CTEC X-ProberM 100%(228) 100%(228)

Row 3 through 6 c AV5TEC X-ProberM 100%(456) 100%(456)

Special Interest<?> H/C Various MRPC 0.3%(17) 0.6%(30)

Post Plugginga> H/C N/A Visual 100%(4) 100%(14)

Upper Internals N/A N/A Visual 100% 100%

Top of Tubesheet<3.> H/C N/A Visual 100% 100%

In-bundle H/C N/A Visual -17% -17%

PLPCV FOSAR H/C N/A Visual N/A N/A Notes:

  • The X-Probe rM deployed contained both a standard bobbin coil and a 16 coil array of transmiUreceive coils.
  • The scope of inspections is provided as a percentage of the open tubes (or plugs) followed by the total number of tests parenthetically (where practical).
  • No tubes were plugged during the RSG manufacturing or prior to service .

CD The Row 7 through 55 inspections were completed from both legs (either hot or cold) over the full length (F/L) of each tube (TEHTEC or TECTEH).

<?) Special Interest MRPC testing is intended to bridge the array coil technology with the previously employed (pre-service inspection (PSI)) +Point' technology. The selection and percentage (number) of tubes was based on both the PSI results and the current inspection results.

a> Post tube plugging visual inspections were conducted by Engineering to validate the tube plug location and proper insertion.

Inspections of the upper internals included the visual inspections of all bolted closures (manways and camera ports), Feedwater Ring (including J-tubes and antistratification (helix) device), Primary (Moisture) Separators, Loose Parts Trapping screens, Downcomer Loose Parts Trapping System (LPTS) and wrapper position per NRC Generic Letter 97-06 and Prairie Island Unit 2 56/19 Replacement Steam Generator Operation and Maintenance Manual.

<3.> Tube lane and periphery of the tube bundle inspected using a camera transport system.

Random fiber-optic inspection of one out of every six columns.

cv Foreign Object Search and Retrieval of possible loose part (PLP) indications for evaluation and possible removal based on eddy current results (not necessary - no PLP's detected in either SG).

Page 4 of17

b. Degradation mechanisms found, Primary Side Inspections - AVB wear and TSP wear were the only degradation mechanisms found in both SGs during 2R29.

For AVB wear the inspection results indicate an improved performance relative to the Unit 1 experience. Only three tubes were identified that contained AVB wear indications, with the largest depth reported at 20% TW. The growth rate experienced by these indications is not abnormally large when compared to industry operating experience (OE) for first cycle AVB wear.

For TSP wear the number of indications in both SGs is increased from that of the Unit 1 experience at the first inspection. There are two facts that can account for this. The first is the amount of run time that Unit 2 had during its first cycle, which allowed for more indications to initiate and grow. Unit 1 first cycle of operation was 1.36 EFPY versus 1.66 EFPY for Unit 2. As expected, the depth distributions for the wear were also slightly higher for Unit 2 compared to that of Unit 1. In addition, a compelling argument for the increase in numbers is the sensitivity of the eddy current methods employed at the Unit 2 inspection. In 2R29, the tubes were inspected with a combination bobbin/array probe over their entire length. The X-Probe' has increased sensitivity, as well as the ability to help clarify bobbin signals. In the data provided (Tables 3 through 6), there are 59 indications that were detectable by the array coils that were not detectable using the bobbin coil. These indications inflate the total number when compared to the Unit 1 first inspection where only bobbin coil was utilized for full length inspections. Even considering this difference, the number, orientation and depth distributions are not outside either the expectations or the industry OE for other RSGs in terms of wear in the first cycle of operation.

Secondary Side Inspections- No secondary side degradation was found. A total of 12 small (all~ 0.25 sq. in.) pieces (five in SG 21 and seven in SG 22) of foreign material (FM) were discovered during the upper bundle inspection on the downcomer LPTS which were subsequently removed. The top of tubesheet and in bundle FOSAR inspections found no FM and no eddy current PLP indications were detected.

c. Nondestructive examination techniques utilized for each degradation mechanism, Table 2 and the notes that follow, provide the Electric Power Research Institute (EPRI) Examination Technique Specification Sheet (ETSS) (techniques) utilized during 2R29 for existing and potential degradation.

Page 5 of 17

TABLE 2 CLASSIFICATION CD MECHANISM LOCATION PROBE TECHNIQUEq)

Bobbin 96004.1 Rev. 13 Potential Wear TSP X-Probe' 11956.1 Rev. 2

+Point' 96910.1 Rev. 10 Bobbin M96041.1 Rev. 4 AVB and Potential Wear X-ProbeTM 11956.1 Rev. 2 Staple

+Point' 10908.3 Rev. 1 Bobbin 27091.2 Rev.1 Potential Wear PLP X-Probe' 20400.1 Rev. 5

+Point' 2790X.1 Rev. 1 Bobbin 13091.1 Rev. 0 Potential Wear Tube-to-Tube X-ProberM 13902.1 Rev. 0

+Point' 13901.1 Rev. 1 Notes:

CD Existing or Potential degradation as defined in the EPRI SGMP: Steam Generator Integrity Assessment Guidelines, Revision 3.

q) Each listed technique was site validated for both detection and sizing except for PLP wear with the X-Probe rM which utilized the above listed technique for detection while sizing would have been based on ETSS 11956.1 Rev. 2 had PLP wear been detected.

In addition, bobbin ETSS's 96010.1 Rev. 7, 24013.1 Rev. 2 and 96007.1 Rev. 12 were site validated for use on non-degradation (MBMs, DNGs, PDSs and cold laps).

M indicates the cited ETSS is an Appendix I qualified technique with system performance quantified using Model Assisted Probability of Detection (MAPOD).

@ X represents 1 through 7 where the user selects the best EPRI ETSS based on the as found wear scar shape and applies the published performance indices for that ETSS.

Page 6 of17

d. Location, orientation (if linear), and measured sizes (if available) of service induced indications, Tables 3 and 4 provide the location, orientation and measured size of each reported TSP wear indication in each steam generator respectively for the degradation found during 2R29. All the tubes in these two tables were returned to service.

Tables 5 and 6 provide the location, orientation and measured sizes of AVB and TSP wear indications in each steam generator respectively for tubes preventively plugged during 2R29. The preventive tube plugging criteria implemented during 2R29 was: 1) any AVB wear~ 8% through wall as measured by the array coils,

2) any TSP wear~ 20% through wall as measured by the array coils, 3) any TSP wear~ 18% through wall as measured by the bobbin coil and 4) any TSP wear with a FLT code (flat non-tapered wear).

Within Table 3, two tubes with a UTIL2 NCA code were detected by the bobbin coil and not confirmed by the array coil. Within Tables 3 through 6, no tubes were reported with multiple VOL calls at the same ROW/COL/LOG/PROBE which would confirm indications of double sided AVB wear or multiple wear location sites on multiple land contact points of a Quatrefoil TSP. Conversely, all VOL calls at the same ROW/COL/LOG/PROBE confirm only single sided wear sites at all AVB and TSP locations.

A legend of fields and codes with brief explanations is provided at the end of this enclosure for clarification purposes.

Page 7 of 17

TABLE 3 Steam Generator 21 TSP Wear TUBE# IND# ROW COL VOLTS INO PCT LOC ELEV PROBE UTIL1 UTIL2 1 1 2 2 0.28 VOL 13 04C -0.46 Array TPR NBC 2 2 3 2 0.27 VOL 13 04C -0.47 Array TPR NBC 3 3 5 2 0.29 VOL 13 04C -0.66 Array TPR NBC 4 4 2 5 0.28 VOL 13 04C -0.65 Array TPR NBC 5 5 5 5 0.21 VOL 12 04C -0.82 Array TPR NBC 6 6 27 11 0.15 WAR 13 02C 0.52 Bobbin CBA 6 6 27 11 0.18 VOL 11 02C 0.35 Array WAR TPR 7 7 37 16 0.15 WAR 13 02C 0.49 Bobbin CBA 7 7 37 16 0.29 VOL 13 02C 0.29 Array WAR TPR 8 8 43 23 0.2 WAR 16 02C 0.52 Bobbin CBA 8 8 43 23 0.54 VOL 17 02C 0.12 Array WAR TPR 9 9 11 39 0.16 WAR 13 03H 0.4 Bobbin CBA 9 9 11 39 0.33 VOL 14 03H 0.49 Array WAR TPR 10 10 46 39 0.22 VOL 12 04H -0.9 Array TPR NBC 11 11 51 41 0.4 VOL 15 04H -0.9 Array TPR NBC 12 12 52 45 0.21 WAR 17 02C 0.69 Bobbin CBA 12 12 52 45 0.33 VOL 14 02C 0.26 Array WAR TPR 12 13 52 45 0.33 VOL 14 04H -0.87 Array TPR NBC 13 14 48 48 0.34 VOL 14 06C -0.96 Array TPR NBC 14 15 53 49 0.11 WAR 10 04H -0.67 Bobbin CBA 14 15 53 49 0.37 VOL 15 04H -0.87 Array WAR TPR 15 16 54 49 0.49 VOL 16 06H -1.01 Array TPR NBC 16 17 53 51 0.49 VOL 16 07H -1.07 Array TPR NBC 17 18 54 52 0.2 VOL 11 03H -0.87 Array TPR NBC 17 19 54 52 0.25 VOL 12 04H -0.82 Array TPR NBC 17 20 54 52 0.37 VOL 15 07H -0.93 Array TPR NBC 18 21 52 53 0.38 VOL 15 04C -1.03 Array TPR NBC 19 22 53 53 0.3 VOL 13 03H -0.84 Array TPR NBC 19 23 53 53 0.37 VOL 15 05H -0.9 Array TPR NBC 20 24 54 53 0.1 WAR 9 06H -0.81 Bobbin CBA 20 24 54 53 0.37 VOL 15 06H -0.92 Array WAR TPR 20 25 54 53 0.32 VOL 14 07H -0.85 Array TPR NBC 21 26 53 54 0.27 VOL 13 06H -0.92 Array TPR NBC 22 27 54 54 0.11 WAR 10 05H 0.35 Bobbin CBA 22 27 54 54 0.32 VOL 14 05H 0.38 Array WAR TPR 23 28 55 54 0.31 VOL 14 06C -0.92 Array TPR NBC 23 29 55 54 0.12 WAR 10 08C -0.7 Bobbin CBA 23 29 55 54 0.44 VOL 16 08C -1.07 Array WAR TPR Page 8 of 17

TABLE 3 Steam Generator 21 TSP Wear TUBE# IND# ROW COL VOLTS INO PCT LOC ELEV PROBE UTIL1 UTIL2 24 30 47 56 0.07 WAR 6 04H -0.66 Bobbin CBA 24 30 47 56 0.3 VOL 13 04H -0.86 Array WAR TPR 25 31 53 56 0.31 VOL 14 04H -0.96 Array TPR NBC 26 32 54 56 0.32 VOL 14 04H -0.87 Array TPR NBC 26 33 54 56 0.4 VOL 15 07H -1.01 Array TPR NBC 27 34 42 58 0.22 WAR 17 05H 0.43 Bobbin CBA 27 34 42 58 0.4 VOL 15 05H 0.29 Array WAR TPR 28 35 52 58 0.09 WAR 8 05H -0.66 Bobbin CBA 28 35 52 58 0.25 VOL 12 05H -0.84 Array WAR TPR 29 36 55 59 0.1 WAR 9 04C -0.87 Bobbin CBA 29 36 55 59 0.22 VOL 12 04C -0.9 Array WAR TPR 29 37 55 59 0.26 VOL 13 08C -0.95 Array TPR NBC 30 38 53 60 0.27 VOL 13 04C -0.93 Array TPR NBC 31 39 54 60 0.12 WAR 10 06C -0.78 Bobbin CBA 31 39 54 60 0.39 VOL 15 06C -0.84 Array WAR TPR 31 39 54 60 0.12 VOL 6 06C -0.77 +Point' WAR TPR 32 40 55 60 0.11 WAR 10 02C -0.63 Bobbin CBA 32 40 55 60 0.36 VOL 14 02C -0.84 Array WAR TPR 33 41 55 61 0.11 WAR 10 04C 0.32 Bobbin CBA 33 41 55 61 0.35 VOL 14 04C 0.12 Array WAR TPR 34 42 26 62 0.14 WAR 12 04H 0.46 Bobbin NCA 35 43 54 66 0.12 WAR 10 05C 0.41 Bobbin CBA 35 43 54 66 0.24 VOL 12 05C 0.46 Array WAR TPR 36 44 49 69 0.12 WAR 10 07H -0.75 Bobbin CBA 36 44 49 69 0.34 VOL 14 07H -1.01 Array WAR TPR 37 45 35 70 0.07 WAR 6 04H -0.67 Bobbin CBA 37 45 35 70 0.28 VOL 13 04H -0.87 Array WAR TPR 38 46 53 70 0.11 WAR 10 03H -0.55 Bobbin CBA 38 46 53 70 0.33 VOL 14 03H -0.87 Array WAR TPR 39 47 50 72 0.07 WAR 7 05C -0.84 Bobbin CBA 39 47 50 72 0.4 VOL 15 05C -0.87 Array WAR TPR 40 48 48 74 0.13 WAR 11 05C 0.4 Bobbin CBA 40 48 48 74 0.31 VOL 14 05C 0.38 Array WAR TPR 41 49 48 79 0.34 VOL 14 06C -1.08 Array TPR NBC 42 50 39 88 0.13 WAR 11 03H 0.4 Bobbin CBA 42 50 39 88 0.36 VOL 14 03H 0.4 Array WAR TPR 43 51 40 90 0.09 WAR 8 05H 0.35 Bobbin CBA 43 51 40 90 0.28 VOL 13 05H 0.32 Array WAR TPR 44 52 42 91 0.27 VOL 13 04H -0.87 Array TPR NBC Page 9 of 17

TABLE 3 Steam Generator 21 TSP Wear TUBE# IND# ROW COL VOLTS INO PCT LOC ELEV PROBE UTIL1 UTIL2 45 53 1 95 0.17 WAR 14 OBH 0.29 Bobbin NCA 46 54 39 95 0.21 VOL 12 06H -0.87 Array TPR NBC 47 55 15 103 0.11 WAR 10 OBC 0.67 Bobbin CBA 47 55 15 103 0.39 VOL 15 OBC 0.64 Array WAR TPR Page 10 of 17

TABLE 4 Steam Generator 22 TSP Wear TUBE# IND# ROW COL VOLTS IND PCT LOC ELEV PROBE UTIL1 UTIL2 1 1 5 2 0.14 WAR 12 04C -0.51 Bobbin CBA 1 1 5 2 0.23 VOL 12 04C -0.84 Array WAR TPR 2 2 1 4 0.24 VOL 12 06C -0.79 Array TPR NBC 3 3 30 16 0.09 WAR 8 04H -0.71 Bobbin CBA 3 3 30 16 0.36 VOL 14 04H -0.9 Array WAR TPR 4 4 37 16 0.15 WAR 13 04H -0.76 Bobbin CBA 4 4 37 16 0.37 VOL 15 04H -0.93 Array WAR TPR 4 5 37 16 0.3 VOL 13 05C -0.85 Array TPR NBC 5 6 37 17 0.13 WAR 11 04H -0.79 Bobbin CBA 5 6 37 17 0.31 VOL 14 04H -0.9 Array WAR TPR 6 7 33 18 0.31 VOL 13 05C -0.76 Array TPR NBC 7 8 45 29 0.31 VOL 14 05C -0.91 Array TPR NBC 8 9 47 30 0.37 VOL 15 05C -0.82 Array TPR NBC 9 10 48 32 0.14 WAR 12 05H -0.76 Bobbin CBA 9 10 48 32 0.61 VOL 18 05H -0.93 Array WAR TPR 9 10 48 32 0.08 VOL 4 05H -0.85 +Point' WAR TPR 10 11 51 35 0.09 WAR 8 04H -0.73 Bobbin CBA 10 11 51 35 0.26 VOL 13 04H -0.9 Array WAR TPR 11 12 51 36 0.07 WAR 6 05H -0.82 Bobbin CBA 11 12 51 36 0.42 VOL 15 05H -0.79 Array WAR TPR 12 13 45 39 0.23 VOL 12 04H -0.88 Array TPR NBC 13 14 48 39 0.3 VOL 13 04H -0.88 Array TPR NBC 14 15 52 39 0.35 VOL 14 04H -0.96 Array TPR NBC 15 16 52 41 0.16 WAR 13 05H -0.74 Bobbin CBA 15 16 52 41 0.51 VOL 17 05H -0.88 Array WAR TPR 15 16 52 41 0.11 VOL 5 05H -0.87 +Point' WAR TPR 15 17 52 41 0.32 VOL 14 07H -0.88 Array TPR NBC 16 18 52 42 0.37 VOL 15 04H -0.9 Array TPR NBC 17 19 53 44 0.34 VOL 14 04H -0.9 Array TPR NBC 18 20 54 47 0.15 WAR 13 04H -0.75 Bobbin CBA 18 20 54 47 0.42 VOL 15 04H -0.95 Array WAR TPR 19 21 52 48 0.36 VOL 14 07H -0.9 Array TPR NBC 20 22 53 48 0.26 VOL 13 07H -0.87 Array TPR NBC 21 23 51 49 0.13 WAR 11 07H -0.72 Bobbin CBA 21 23 51 49 0.35 VOL 14 07H -0.95 Array WAR TPR 22 24 54 54 0.12 WAR 11 07H -1.01 Bobbin CBA 22 24 54 54 0.45 VOL 16 07H -0.9 Array WAR TPR 22 24 54 54 0.1 VOL 5 07H -0.82 +Point' WAR TPR 22 25 54 54 0.39 VOL 15 08H -0.98 Array TPR NBC Page 11 of 17

TABLE 4 Steam Generator 22 TSP Wear TUBE# IND# ROW COL VOLTS IND PCT LOC ELEV PROBE UTIL1 UTIL2 23 26 55 55 0.14 WAR 12 04C -0.63 Bobbin CBA 23 26 55 55 0.5 VOL 16 04C -0.83 Array WAR TPR 23 27 55 55 0.1 WAR 9 07H -0.72 Bobbin CBA 23 27 55 55 0.39 VOL 15 07H -0.89 Array WAR TPR 24 28 54 56 0.28 VOL 13 07H -0.87 Array TPR NBC 25 29 55 56 0.16 WAR 13 07H -0.81 Bobbin CBA 25 29 55 56 0.58 VOL 17 07H -0.9 Array WAR TPR 26 30 21 57 0.14 WAR 12 08H 0.69 Bobbin CBA 26 30 21 57 0.28 VOL 13 08H 0.61 Array WAR TPR 27 31 55 57 0.19 WAR 15 01H -0.61 Bobbin CBA 27 31 55 57 0.27 VOL 13 01H -0.84 Array WAR TPR 27 32 55 57 0.22 WAR 17 07H -0.75 Bobbin CBA 27 32 55 57 0.73 VOL 19 07H -0.92 Array WAR TPR 27 32 55 57 0.21 VOL 10 07H -0.87 +Point' WAR TPR 28 33 55 61 0.17 WAR 14 02C 0.42 Bobbin CBA 28 33 55 61 0.47 VOL 16 02C 0.31 Array WAR TPR 29 34 54 62 0.19 WAR 15 02C 0.39 Bobbin CBA 29 34 54 62 0.69 VOL 19 02C 0.17 Array WAR TPR 29 34 54 62 0.3 VOL 13 02C -0.2 +Point' WAR TPR 29 35 54 62 0.08 WAR 7 07C -0.65 Bobbin CBA 29 35 54 62 0.42 VOL 15 07C -0.87 Array WAR TPR 30 36 49 64 0.32 VOL 14 07H -0.91 Array TPR NBC 31 37 54 64 0.13 WAR 11 05H -0.62 Bobbin CBA 31 37 54 64 0.31 VOL 14 05H -0.85 Array WAR TPR 32 38 53 68 0.12 WAR 10 04H -0.65 Bobbin CBA 32 38 53 68 0.42 VOL 15 04H -0.9 Array WAR TPR 32 39 53 68 0.33 VOL 14 08C -0.98 Array TPR NBC 33 40 52 69 0.11 WAR 10 04H -0.64 Bobbin CBA 33 40 52 69 0.31 VOL 14 04H -0.9 Array WAR TPR 34 41 53 70 0.34 VOL 14 04C -0.9 Array TPR NBC 35 42 39 75 0.15 WAR 13 06C -0.84 Bobbin CBA 35 42 39 75 0.32 VOL 14 06C -1.04 Array WAR TPR 36 43 14 76 0.17 VOL 11 03H 0.64 Array TPR NBC 37 44 38 76 0.22 WAR 17 03C 0.42 Bobbin CBA 37 44 38 76 0.39 VOL 15 03C 0.37 Array WAR TPR 38 45 50 78 0.33 VOL 14 07H -1 Array TPR NBC 39 46 47 86 0.13 WAR 11 02C 0.45 Bobbin CBA 39 46 47 86 0.32 VOL 14 02C 0.31 Array WAR TPR 40 47 24 87 0.19 VOL 11 01C -0.89 Array TPR NBC Page 12 of 17

TABLE 4 Steam Generator 22 TSP Wear TUBE# IND# ROW COL VOLTS IND PCT LOC ELEV PROBE UTIL1 UTIL2 41 48 45 87 0.22 VOL 12 08C -1.02 Array TPR NBC 42 49 46 88 0.28 VOL 13 04H -0.82 Array TPR NBC 43 50 45 90 0.15 WAR 13 05H -0.65 Bobbin CBA 43 50 45 90 0.33 VOL 14 05H -0.93 Array WAR TPR 44 51 44 91 0.25 VOL 12 05H -0.93 Array TPR NBC 45 52 41 93 0.58 VOL 17 05H -0.93 Array TPR NBC 46 53 41 94 0.14 WAR 12 04H -0.65 Bobbin CBA 46 53 41 94 0.48 VOL 16 04H -0.87 Array WAR TPR 47 54 38 97 . 0.15 WAR 13 04H -0.65 Bobbin CBA 47 54 38 97 0.24 VOL 12 04H -0.48 Array WAR TPR 48 55 8 100 0.15 WAR 13 03H -0.7 Bobbin CBA 48 55 8 100 0.34 VOL 14 03H -0.87 Array WAR TPR 49 56 30 102 0.16 WAR 13 04H -0.65 Bobbin CBA 49 56 30 102 0.24 VOL 12 04H -0.93 Array WAR TPR 50 57 27 106 0.22 VOL 12 05C -1.07 Array TPR NBC 51 58 22 107 0.13 WAR 11 . 05H -0.74 Bobbin CBA 51 58 22 107 0.45 VOL 16 05H -0.96 Array WAR TPR 52 59 26 107 0.23 VOL 12 05C -0.93 Array TPR NBC 53 60 13 108 0.26 VOL 13 04C -0.99 Array TPR NBC 54 61 16 111 0.54 VOL 15 05H -0.93 Array TPR NBC 55 62 6 112 0.32 VOL 14 04C -0.9 Array TPR NBC 56 63 6 113 0.14 WAR 12 04H -0.48 Bobbin CBA 56 63 6 113 0.47 VOL 16 04H -0.96 Array WAR TPR Page 13 of 17

TABLE 5 Steam Generator 21 Tube Plugging TUBE# IND# ROW COL VOLTS IND PCT LOC ELEV PROBE UTIL1 UTIL2 1 1 53 45 0.24 VOL 12 AV9 -0.11 Array FLT NBC 1 1 53 45 0.09 VOL 5 AV9 -0.04 +Point' WAR TPR 2 2 45 61 0.19 AVB 6 AV7 0 Bobbin CBA 2 2 45 61 0.86 VOL 20 AV7 -0.35 Array WAR FLT 2 2 45 61 0.24 VOL 12 AV7 -0.29 +Point' WAR FLT Page 14 of 17

TABLE 6 Steam Generator 22 Tube Plugging TUBE# IND# ROW COL VOLTS IND PCT LOC ELEV PROBE UTIL1 UTIL2 1 1 39 57 0.38 VOL 15 AV7 -0.43 Arrav TPR NBC 1 1 39 57 0.13 VOL 5 AV7 -0.22 +Point' WAR FLT 2 2 54 58 0.26 WAR 19 02C 0.39 Bobbin CBA 2 2 54 58 0.58 VOL 17 02C 0.22 Array WAR TPR 2 2 54 58 0.24 VOL 10 02C -0.09 +Point' WAR TPR 3 3 54 59 0.26 WAR 19 02C 0.39 Bobbin CBA 3 3 54 59 0.73 VOL 19 02C 0.06 Arrav WAR TPR 3 3 54 59 0.32 VOL 13 02C -0.11 +Point' WAR TPR 3 4 54 59 0.12 WAR 10 03C -0.82 Bobbin CBA 3 4 54 59 0.55 VOL 17 03C -0.87 Arrav WAR TPR 3 4 54 59 0.15 VOL 7 03C -0.82 +Point' WAR TPR 4 5 55 59 0.26 WAR 19 02C 0.39 Bobbin CBA 4 5 55 59 0.56 VOL 17 02C 0.11 Array WAR TPR 4 5 55 59 0.22 VOL 10 02C -0.07 +Point' WAR TPR 4 6 55 59 0.22 WAR 17 04C 0.37 Bobbin CBA 4 6 55 59 0.79 VOL 20 04C -0.08 Array WAR TPR 4 6 55 59 0.22 VOL 10 04C -0.54 +Point' WAR TPR 5 7 54 61 0.53 WAR 31 01C -0.11 Bobbin CBA 5 7 54 61 1.48 VOL 25 01C -0.73 Arrav WAR FLT 5 7 54 61 0.4 VOL 17 01C -0.57 +Point' WAR FLT 5 8 54 61 0.21 WAR 16 02C 0.42 Bobbin CBA 5 8 54 61 0.66 VOL 18 02C 0.11 Arrav WAR TPR 6 9 54 63 0.27 WAR 20 02C 0.42 Bobbin CBA 6 9 54 63 0.77 VOL 20 02C 0.11 Arrav WAR TPR 6 9 54 63 0.24 VOL 11 02C -0.2 +Point' WAR TPR 7 10 31 104 0.23 WAR 18 05H 0.42 Bobbin CBA 7 10 31 104 0.44 VOL 16 05H 0.25 Arrav WAR TPR 7 10 31 104 0.22 VOL 10 05H 0.18 +Point' WAR TPR Page 15 of 17

e. Number of tubes plugged during the inspection outage for each degradation mechanism, Table 7 provides the number of tubes plugged during 2R29.

TABLE 7 MECHANISM SG 21 SG 22 AVBWear 2 1 TSPWear 0 6

f. The number and percentage of tubes plugged to date, and the effective plugging percentage in each steam generator, and Table 8 provides the total number and percentage of tubes plugged to date.

TABLE 8 PLUGGING SG 21 SG22 TOTAL 2 7 PERCENT 0.04% 0.14%

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

The deepest AVB wear indication reported during 2R29 was 20%TWas reported from the X-Probe TM. The condition monitoring (CM) limit for flat (uniformly deep)

AVB wear is 47.2%TW. As the deepest indication is of lesser depth than the CM limit, CM is satisfied.

The deepest TSP wear indication reported during 2R29 was 25% TWas reported from X-Probe', and is the only TSP wear indication with a flat profile. The flat wear TSP CM limit is 49.5% TW. As the deepest indication is of lesser depth than the CM limit, CM is satisfied.

The deepest TSP wear indication with a tapered profile was 20% TWas reported from X-Probe'. The tapered wear TSP CM limit is 60%TW. As the deepest indication is of lesser depth than the CM limit, CM is satisfied.

Additionally, an operation assessment (OA) was performed that provides reasonable assurance that the performance criteria will not be exceeded during the upcoming operating cycles 29 and 30 until the next planned SG inspection.

Page 16 of 17

LEGEND OF FIELDS AND CODES FIELD EXPLANATION TUBE# Distinct ROW/COL combination within each Table IND# Distinct ROW/COL/LOCATION combination within each Table ROW Row number of tube location COL Column number of tube location VOLTS Measured Voltage IND Three Digit Code - see below PCT Measured percent through wall LOC Location of landmark - see below ELEV Measurement in inches from the center of the landmark to the center of the indication PROBE Probe Coil Type -Array, Bobbin or +Point' UTIL1 Clarifying Codes - see below UTIL2 Clarifying Codes - see below FIELD CODE EXPLANATION IND AVB Anti-Vibration Bar VOL Volumetric WAR Wear LOC O?H  ? = First through Eighth tube support plate on hot leg side AV?  ? =First through Ninth anti-vibration bar O?C  ? =First through Eighth tube support plate on cold leg side UTIL1 CBA Confirmed By Array coil or FLT Flat (non-tapered) wear UTIL2 NBC No Bobbin Call NCA Not Confirmed by Array coil TPR Tapered wear WAR Wear Page 17 of 17

Prairie Island Nuclear Generating Plant Xcel Energy@ 1717 Wakonade Drive East Welch. MN 55089 MAY 2 0 2016 L-PI-16-030 TS 5.6.7 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Prairie Island Nuclear Generating Plant Unit 2 Docket 50-306 Renewed Facility Operating License No. DPR-60 2015 Unit 2 180-Day Steam Generator Tube Inspection Report In accordance with Prairie Island Nuclear Generating Plant, Unit 2, Technical Specification 5.6.7, "Steam Generator Tube Inspection Report," Northern States Power Company, a Minnesota corporation, doing business as Xcel Energy (hereafter "NSPM")

submits the enclosed report of steam generator tube inspections performed during the 2015 refueling and maintenance outage on Unit 2.

Summary of Commitments This letter contains no new commitment and no revision to an existing commitment.

Scott Northard Acting Site Vice President - Prairie Island Nuclear Generating Plant Northern States Power Company- Minnesota Enclosure (1) cc: Administrator, Region Ill, USNRC Project Manager, Prairie Island, USNRC Resident Inspector, Prairie Island, USNRC

Enclosure 1 Prairie Island Nuclear Generating Plant- Unit 2 2015 Steam Generator Tube Inspection Report

( 17 pages follow)

ENCLOSURE 1 Prairie Island Nuclear Generating Plant- Unit 2 2015 Steam Generator Tube Inspection Report In accordance with Prairie Island Nuclear Generating Plant (PINGP), Unit 2 Technical Specification 5.6.7, Xcel Energy Nuclear Department submits this report of steam generator tube inspections performed during the 2015 refueling and maintenance outage for Unit 2 (2R29).

PINGP Unit 2 has two Areva Model 56/19 Replacement Steam Generators (RSGs) with approximately 5,600 square meters of heat transfer area utilizing tubes with 19 millimeter outside diameter. Each RSG has 4,868 thermally-treated Alloy 690 u-tubes manufactured by Sandvik which have an outside diameter of 0. 750 inch and a nominal wall thickness of 0.043 inch. The tubes are configured in a square pitch of 1.0425 inches with 55 rows and 114 columns (see Figure 1). The tube u-bends vary in radius from 2.7000 inches for a row 1 tube to 58.9950 inches for a row 55 tube. The tubes vary in length from 738.16 inches for row 1 tubes to 923.04 inches for row 55 tubes. Row 1 through row 9 tubes were subject to stress relieving following the bending process using the thermal treatment process for an additional 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> minimum soak time. The tubes were hydraulically expanded at each end for the full depth of the tubesheet with the expansion transition being between 0.079 inches and 0.236 inches below the secondary tubesheet face.

The tubesheet is low alloy steel 21.46 inches thick with alloys 82 and 182 cladding 0.375" thick for an overall thickness of 21.835 inches. The tubes are supported by eight tube support plates (TSPs) and five anti-vibration bars (AVBs) intersecting tubes between 1, 3, 5, 7 and 9 times (see Figure 2). There is one straight bar that intersects all rows at the center of each bend, two 57 degree bars that intersect rows 13 through 55 and two 14 degree bars that intersect rows 25 through 55. In addition there are 24 peripheral tubes with nine staples (one at each AVB location) that carry the entire load of the complete AVB assembly. All TSPs are constructed from Type 410 stainless steel. The TSPs have a minimum thickness of 1.18 inch and have quatrefoil-shaped holes through which the tubes pass. The AVBs are constructed from Type 405 stainless steel and are rectangular in cross section (nominally 0.5 inch by 0.3 inch).

Each RSG is equipped with a Loose Parts Trapping Systems (LPTS), which is composed of screens at the top of the downcomer and at the top of the primary (cyclone) separators.

These screens (0.14" square mesh formed from 0.031" diameter wire), prevent foreign material from entering the steam generator tube area from the main feedwater and auxiliary feedwater systems (see Figure 2).

Page I of 17

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loose Parts Tra~~iH9 Systems

---UPPERMOST TSP Figure 2 The original Westinghouse Model 51 Steam Generators (SGs) were replaced during the 2013 refueling outage after 33.56 EFPY of operation. During the 2015 refueling outage the first in-service inspection (lSI) was conducted on the RSGs after accumulating the initial 1.66 EFPY of RSG operation.

Italicized text represents technical specification excerpts. Each excerpt is followed by the appropriate information intended to address each specific NOTE: requirement and also includes additional details based on benchmarking previous submittals and Staff requests for additional information of peer Licensees. A legend of codes and field names is included at the end of the report.

5. 6 Reporting Requirements
5. 6. 7 Steam Generator Tube Inspection Report A report shall be submitted within 180 days after initial entry into MODE 4 following completion of an inspection performed in accordance with the Specification 5. 5. 8, Steam Generator (SG) Program.

Initial entry into MODE 4 occurred on November 27, 2015, dictating submittal of this report on or before May 25, 2016.

The report shall include:

a. The scope of inspections performed on each SG, Table 1 and the notes that follow, provides the scope of inspections performed during 2R29.

Page 3 of 17

TABLE 1 SCOPE LEG EXTENT TECHNIQUE SG 21 SG22 Row 7 through 55CD H/C F/L X-ProberM 100%(4184) 100%(4184)

Row 3 through 6 H AV5TEH X-ProberM 100%(456) 100%(456)

Row 1 through 2 H 08HTEH X-ProberM 100%(228) 100%(228)

Row 1 through 2 H 08CTEH Bobbin N/A 100%(228)

Row 1 through 2 c 08HTEC Bobbin 100%(228) N/A Row 1 through 2 c 08CTEC X-ProberM 100%(228) 100%(228)

Row 3 through 6 c AV5TEC X-ProberM 100%(456) 100%(456)

Special Interest<?> H/C Various MRPC 0.3%(17) 0.6%(30)

Post Plugginga> H/C N/A Visual 100%(4) 100%(14)

Upper Internals N/A N/A Visual 100% 100%

Top of Tubesheet<3.> H/C N/A Visual 100% 100%

In-bundle H/C N/A Visual -17% -17%

PLPCV FOSAR H/C N/A Visual N/A N/A Notes:

  • The X-Probe rM deployed contained both a standard bobbin coil and a 16 coil array of transmiUreceive coils.
  • The scope of inspections is provided as a percentage of the open tubes (or plugs) followed by the total number of tests parenthetically (where practical).
  • No tubes were plugged during the RSG manufacturing or prior to service .

CD The Row 7 through 55 inspections were completed from both legs (either hot or cold) over the full length (F/L) of each tube (TEHTEC or TECTEH).

<?) Special Interest MRPC testing is intended to bridge the array coil technology with the previously employed (pre-service inspection (PSI)) +Point' technology. The selection and percentage (number) of tubes was based on both the PSI results and the current inspection results.

a> Post tube plugging visual inspections were conducted by Engineering to validate the tube plug location and proper insertion.

Inspections of the upper internals included the visual inspections of all bolted closures (manways and camera ports), Feedwater Ring (including J-tubes and antistratification (helix) device), Primary (Moisture) Separators, Loose Parts Trapping screens, Downcomer Loose Parts Trapping System (LPTS) and wrapper position per NRC Generic Letter 97-06 and Prairie Island Unit 2 56/19 Replacement Steam Generator Operation and Maintenance Manual.

<3.> Tube lane and periphery of the tube bundle inspected using a camera transport system.

Random fiber-optic inspection of one out of every six columns.

cv Foreign Object Search and Retrieval of possible loose part (PLP) indications for evaluation and possible removal based on eddy current results (not necessary - no PLP's detected in either SG).

Page 4 of17

b. Degradation mechanisms found, Primary Side Inspections - AVB wear and TSP wear were the only degradation mechanisms found in both SGs during 2R29.

For AVB wear the inspection results indicate an improved performance relative to the Unit 1 experience. Only three tubes were identified that contained AVB wear indications, with the largest depth reported at 20% TW. The growth rate experienced by these indications is not abnormally large when compared to industry operating experience (OE) for first cycle AVB wear.

For TSP wear the number of indications in both SGs is increased from that of the Unit 1 experience at the first inspection. There are two facts that can account for this. The first is the amount of run time that Unit 2 had during its first cycle, which allowed for more indications to initiate and grow. Unit 1 first cycle of operation was 1.36 EFPY versus 1.66 EFPY for Unit 2. As expected, the depth distributions for the wear were also slightly higher for Unit 2 compared to that of Unit 1. In addition, a compelling argument for the increase in numbers is the sensitivity of the eddy current methods employed at the Unit 2 inspection. In 2R29, the tubes were inspected with a combination bobbin/array probe over their entire length. The X-Probe' has increased sensitivity, as well as the ability to help clarify bobbin signals. In the data provided (Tables 3 through 6), there are 59 indications that were detectable by the array coils that were not detectable using the bobbin coil. These indications inflate the total number when compared to the Unit 1 first inspection where only bobbin coil was utilized for full length inspections. Even considering this difference, the number, orientation and depth distributions are not outside either the expectations or the industry OE for other RSGs in terms of wear in the first cycle of operation.

Secondary Side Inspections- No secondary side degradation was found. A total of 12 small (all~ 0.25 sq. in.) pieces (five in SG 21 and seven in SG 22) of foreign material (FM) were discovered during the upper bundle inspection on the downcomer LPTS which were subsequently removed. The top of tubesheet and in bundle FOSAR inspections found no FM and no eddy current PLP indications were detected.

c. Nondestructive examination techniques utilized for each degradation mechanism, Table 2 and the notes that follow, provide the Electric Power Research Institute (EPRI) Examination Technique Specification Sheet (ETSS) (techniques) utilized during 2R29 for existing and potential degradation.

Page 5 of 17

TABLE 2 CLASSIFICATION CD MECHANISM LOCATION PROBE TECHNIQUEq)

Bobbin 96004.1 Rev. 13 Potential Wear TSP X-Probe' 11956.1 Rev. 2

+Point' 96910.1 Rev. 10 Bobbin M96041.1 Rev. 4 AVB and Potential Wear X-ProbeTM 11956.1 Rev. 2 Staple

+Point' 10908.3 Rev. 1 Bobbin 27091.2 Rev.1 Potential Wear PLP X-Probe' 20400.1 Rev. 5

+Point' 2790X.1 Rev. 1 Bobbin 13091.1 Rev. 0 Potential Wear Tube-to-Tube X-ProberM 13902.1 Rev. 0

+Point' 13901.1 Rev. 1 Notes:

CD Existing or Potential degradation as defined in the EPRI SGMP: Steam Generator Integrity Assessment Guidelines, Revision 3.

q) Each listed technique was site validated for both detection and sizing except for PLP wear with the X-Probe rM which utilized the above listed technique for detection while sizing would have been based on ETSS 11956.1 Rev. 2 had PLP wear been detected.

In addition, bobbin ETSS's 96010.1 Rev. 7, 24013.1 Rev. 2 and 96007.1 Rev. 12 were site validated for use on non-degradation (MBMs, DNGs, PDSs and cold laps).

M indicates the cited ETSS is an Appendix I qualified technique with system performance quantified using Model Assisted Probability of Detection (MAPOD).

@ X represents 1 through 7 where the user selects the best EPRI ETSS based on the as found wear scar shape and applies the published performance indices for that ETSS.

Page 6 of17

d. Location, orientation (if linear), and measured sizes (if available) of service induced indications, Tables 3 and 4 provide the location, orientation and measured size of each reported TSP wear indication in each steam generator respectively for the degradation found during 2R29. All the tubes in these two tables were returned to service.

Tables 5 and 6 provide the location, orientation and measured sizes of AVB and TSP wear indications in each steam generator respectively for tubes preventively plugged during 2R29. The preventive tube plugging criteria implemented during 2R29 was: 1) any AVB wear~ 8% through wall as measured by the array coils,

2) any TSP wear~ 20% through wall as measured by the array coils, 3) any TSP wear~ 18% through wall as measured by the bobbin coil and 4) any TSP wear with a FLT code (flat non-tapered wear).

Within Table 3, two tubes with a UTIL2 NCA code were detected by the bobbin coil and not confirmed by the array coil. Within Tables 3 through 6, no tubes were reported with multiple VOL calls at the same ROW/COL/LOG/PROBE which would confirm indications of double sided AVB wear or multiple wear location sites on multiple land contact points of a Quatrefoil TSP. Conversely, all VOL calls at the same ROW/COL/LOG/PROBE confirm only single sided wear sites at all AVB and TSP locations.

A legend of fields and codes with brief explanations is provided at the end of this enclosure for clarification purposes.

Page 7 of 17

TABLE 3 Steam Generator 21 TSP Wear TUBE# IND# ROW COL VOLTS INO PCT LOC ELEV PROBE UTIL1 UTIL2 1 1 2 2 0.28 VOL 13 04C -0.46 Array TPR NBC 2 2 3 2 0.27 VOL 13 04C -0.47 Array TPR NBC 3 3 5 2 0.29 VOL 13 04C -0.66 Array TPR NBC 4 4 2 5 0.28 VOL 13 04C -0.65 Array TPR NBC 5 5 5 5 0.21 VOL 12 04C -0.82 Array TPR NBC 6 6 27 11 0.15 WAR 13 02C 0.52 Bobbin CBA 6 6 27 11 0.18 VOL 11 02C 0.35 Array WAR TPR 7 7 37 16 0.15 WAR 13 02C 0.49 Bobbin CBA 7 7 37 16 0.29 VOL 13 02C 0.29 Array WAR TPR 8 8 43 23 0.2 WAR 16 02C 0.52 Bobbin CBA 8 8 43 23 0.54 VOL 17 02C 0.12 Array WAR TPR 9 9 11 39 0.16 WAR 13 03H 0.4 Bobbin CBA 9 9 11 39 0.33 VOL 14 03H 0.49 Array WAR TPR 10 10 46 39 0.22 VOL 12 04H -0.9 Array TPR NBC 11 11 51 41 0.4 VOL 15 04H -0.9 Array TPR NBC 12 12 52 45 0.21 WAR 17 02C 0.69 Bobbin CBA 12 12 52 45 0.33 VOL 14 02C 0.26 Array WAR TPR 12 13 52 45 0.33 VOL 14 04H -0.87 Array TPR NBC 13 14 48 48 0.34 VOL 14 06C -0.96 Array TPR NBC 14 15 53 49 0.11 WAR 10 04H -0.67 Bobbin CBA 14 15 53 49 0.37 VOL 15 04H -0.87 Array WAR TPR 15 16 54 49 0.49 VOL 16 06H -1.01 Array TPR NBC 16 17 53 51 0.49 VOL 16 07H -1.07 Array TPR NBC 17 18 54 52 0.2 VOL 11 03H -0.87 Array TPR NBC 17 19 54 52 0.25 VOL 12 04H -0.82 Array TPR NBC 17 20 54 52 0.37 VOL 15 07H -0.93 Array TPR NBC 18 21 52 53 0.38 VOL 15 04C -1.03 Array TPR NBC 19 22 53 53 0.3 VOL 13 03H -0.84 Array TPR NBC 19 23 53 53 0.37 VOL 15 05H -0.9 Array TPR NBC 20 24 54 53 0.1 WAR 9 06H -0.81 Bobbin CBA 20 24 54 53 0.37 VOL 15 06H -0.92 Array WAR TPR 20 25 54 53 0.32 VOL 14 07H -0.85 Array TPR NBC 21 26 53 54 0.27 VOL 13 06H -0.92 Array TPR NBC 22 27 54 54 0.11 WAR 10 05H 0.35 Bobbin CBA 22 27 54 54 0.32 VOL 14 05H 0.38 Array WAR TPR 23 28 55 54 0.31 VOL 14 06C -0.92 Array TPR NBC 23 29 55 54 0.12 WAR 10 08C -0.7 Bobbin CBA 23 29 55 54 0.44 VOL 16 08C -1.07 Array WAR TPR Page 8 of 17

TABLE 3 Steam Generator 21 TSP Wear TUBE# IND# ROW COL VOLTS INO PCT LOC ELEV PROBE UTIL1 UTIL2 24 30 47 56 0.07 WAR 6 04H -0.66 Bobbin CBA 24 30 47 56 0.3 VOL 13 04H -0.86 Array WAR TPR 25 31 53 56 0.31 VOL 14 04H -0.96 Array TPR NBC 26 32 54 56 0.32 VOL 14 04H -0.87 Array TPR NBC 26 33 54 56 0.4 VOL 15 07H -1.01 Array TPR NBC 27 34 42 58 0.22 WAR 17 05H 0.43 Bobbin CBA 27 34 42 58 0.4 VOL 15 05H 0.29 Array WAR TPR 28 35 52 58 0.09 WAR 8 05H -0.66 Bobbin CBA 28 35 52 58 0.25 VOL 12 05H -0.84 Array WAR TPR 29 36 55 59 0.1 WAR 9 04C -0.87 Bobbin CBA 29 36 55 59 0.22 VOL 12 04C -0.9 Array WAR TPR 29 37 55 59 0.26 VOL 13 08C -0.95 Array TPR NBC 30 38 53 60 0.27 VOL 13 04C -0.93 Array TPR NBC 31 39 54 60 0.12 WAR 10 06C -0.78 Bobbin CBA 31 39 54 60 0.39 VOL 15 06C -0.84 Array WAR TPR 31 39 54 60 0.12 VOL 6 06C -0.77 +Point' WAR TPR 32 40 55 60 0.11 WAR 10 02C -0.63 Bobbin CBA 32 40 55 60 0.36 VOL 14 02C -0.84 Array WAR TPR 33 41 55 61 0.11 WAR 10 04C 0.32 Bobbin CBA 33 41 55 61 0.35 VOL 14 04C 0.12 Array WAR TPR 34 42 26 62 0.14 WAR 12 04H 0.46 Bobbin NCA 35 43 54 66 0.12 WAR 10 05C 0.41 Bobbin CBA 35 43 54 66 0.24 VOL 12 05C 0.46 Array WAR TPR 36 44 49 69 0.12 WAR 10 07H -0.75 Bobbin CBA 36 44 49 69 0.34 VOL 14 07H -1.01 Array WAR TPR 37 45 35 70 0.07 WAR 6 04H -0.67 Bobbin CBA 37 45 35 70 0.28 VOL 13 04H -0.87 Array WAR TPR 38 46 53 70 0.11 WAR 10 03H -0.55 Bobbin CBA 38 46 53 70 0.33 VOL 14 03H -0.87 Array WAR TPR 39 47 50 72 0.07 WAR 7 05C -0.84 Bobbin CBA 39 47 50 72 0.4 VOL 15 05C -0.87 Array WAR TPR 40 48 48 74 0.13 WAR 11 05C 0.4 Bobbin CBA 40 48 48 74 0.31 VOL 14 05C 0.38 Array WAR TPR 41 49 48 79 0.34 VOL 14 06C -1.08 Array TPR NBC 42 50 39 88 0.13 WAR 11 03H 0.4 Bobbin CBA 42 50 39 88 0.36 VOL 14 03H 0.4 Array WAR TPR 43 51 40 90 0.09 WAR 8 05H 0.35 Bobbin CBA 43 51 40 90 0.28 VOL 13 05H 0.32 Array WAR TPR 44 52 42 91 0.27 VOL 13 04H -0.87 Array TPR NBC Page 9 of 17

TABLE 3 Steam Generator 21 TSP Wear TUBE# IND# ROW COL VOLTS INO PCT LOC ELEV PROBE UTIL1 UTIL2 45 53 1 95 0.17 WAR 14 OBH 0.29 Bobbin NCA 46 54 39 95 0.21 VOL 12 06H -0.87 Array TPR NBC 47 55 15 103 0.11 WAR 10 OBC 0.67 Bobbin CBA 47 55 15 103 0.39 VOL 15 OBC 0.64 Array WAR TPR Page 10 of 17

TABLE 4 Steam Generator 22 TSP Wear TUBE# IND# ROW COL VOLTS IND PCT LOC ELEV PROBE UTIL1 UTIL2 1 1 5 2 0.14 WAR 12 04C -0.51 Bobbin CBA 1 1 5 2 0.23 VOL 12 04C -0.84 Array WAR TPR 2 2 1 4 0.24 VOL 12 06C -0.79 Array TPR NBC 3 3 30 16 0.09 WAR 8 04H -0.71 Bobbin CBA 3 3 30 16 0.36 VOL 14 04H -0.9 Array WAR TPR 4 4 37 16 0.15 WAR 13 04H -0.76 Bobbin CBA 4 4 37 16 0.37 VOL 15 04H -0.93 Array WAR TPR 4 5 37 16 0.3 VOL 13 05C -0.85 Array TPR NBC 5 6 37 17 0.13 WAR 11 04H -0.79 Bobbin CBA 5 6 37 17 0.31 VOL 14 04H -0.9 Array WAR TPR 6 7 33 18 0.31 VOL 13 05C -0.76 Array TPR NBC 7 8 45 29 0.31 VOL 14 05C -0.91 Array TPR NBC 8 9 47 30 0.37 VOL 15 05C -0.82 Array TPR NBC 9 10 48 32 0.14 WAR 12 05H -0.76 Bobbin CBA 9 10 48 32 0.61 VOL 18 05H -0.93 Array WAR TPR 9 10 48 32 0.08 VOL 4 05H -0.85 +Point' WAR TPR 10 11 51 35 0.09 WAR 8 04H -0.73 Bobbin CBA 10 11 51 35 0.26 VOL 13 04H -0.9 Array WAR TPR 11 12 51 36 0.07 WAR 6 05H -0.82 Bobbin CBA 11 12 51 36 0.42 VOL 15 05H -0.79 Array WAR TPR 12 13 45 39 0.23 VOL 12 04H -0.88 Array TPR NBC 13 14 48 39 0.3 VOL 13 04H -0.88 Array TPR NBC 14 15 52 39 0.35 VOL 14 04H -0.96 Array TPR NBC 15 16 52 41 0.16 WAR 13 05H -0.74 Bobbin CBA 15 16 52 41 0.51 VOL 17 05H -0.88 Array WAR TPR 15 16 52 41 0.11 VOL 5 05H -0.87 +Point' WAR TPR 15 17 52 41 0.32 VOL 14 07H -0.88 Array TPR NBC 16 18 52 42 0.37 VOL 15 04H -0.9 Array TPR NBC 17 19 53 44 0.34 VOL 14 04H -0.9 Array TPR NBC 18 20 54 47 0.15 WAR 13 04H -0.75 Bobbin CBA 18 20 54 47 0.42 VOL 15 04H -0.95 Array WAR TPR 19 21 52 48 0.36 VOL 14 07H -0.9 Array TPR NBC 20 22 53 48 0.26 VOL 13 07H -0.87 Array TPR NBC 21 23 51 49 0.13 WAR 11 07H -0.72 Bobbin CBA 21 23 51 49 0.35 VOL 14 07H -0.95 Array WAR TPR 22 24 54 54 0.12 WAR 11 07H -1.01 Bobbin CBA 22 24 54 54 0.45 VOL 16 07H -0.9 Array WAR TPR 22 24 54 54 0.1 VOL 5 07H -0.82 +Point' WAR TPR 22 25 54 54 0.39 VOL 15 08H -0.98 Array TPR NBC Page 11 of 17

TABLE 4 Steam Generator 22 TSP Wear TUBE# IND# ROW COL VOLTS IND PCT LOC ELEV PROBE UTIL1 UTIL2 23 26 55 55 0.14 WAR 12 04C -0.63 Bobbin CBA 23 26 55 55 0.5 VOL 16 04C -0.83 Array WAR TPR 23 27 55 55 0.1 WAR 9 07H -0.72 Bobbin CBA 23 27 55 55 0.39 VOL 15 07H -0.89 Array WAR TPR 24 28 54 56 0.28 VOL 13 07H -0.87 Array TPR NBC 25 29 55 56 0.16 WAR 13 07H -0.81 Bobbin CBA 25 29 55 56 0.58 VOL 17 07H -0.9 Array WAR TPR 26 30 21 57 0.14 WAR 12 08H 0.69 Bobbin CBA 26 30 21 57 0.28 VOL 13 08H 0.61 Array WAR TPR 27 31 55 57 0.19 WAR 15 01H -0.61 Bobbin CBA 27 31 55 57 0.27 VOL 13 01H -0.84 Array WAR TPR 27 32 55 57 0.22 WAR 17 07H -0.75 Bobbin CBA 27 32 55 57 0.73 VOL 19 07H -0.92 Array WAR TPR 27 32 55 57 0.21 VOL 10 07H -0.87 +Point' WAR TPR 28 33 55 61 0.17 WAR 14 02C 0.42 Bobbin CBA 28 33 55 61 0.47 VOL 16 02C 0.31 Array WAR TPR 29 34 54 62 0.19 WAR 15 02C 0.39 Bobbin CBA 29 34 54 62 0.69 VOL 19 02C 0.17 Array WAR TPR 29 34 54 62 0.3 VOL 13 02C -0.2 +Point' WAR TPR 29 35 54 62 0.08 WAR 7 07C -0.65 Bobbin CBA 29 35 54 62 0.42 VOL 15 07C -0.87 Array WAR TPR 30 36 49 64 0.32 VOL 14 07H -0.91 Array TPR NBC 31 37 54 64 0.13 WAR 11 05H -0.62 Bobbin CBA 31 37 54 64 0.31 VOL 14 05H -0.85 Array WAR TPR 32 38 53 68 0.12 WAR 10 04H -0.65 Bobbin CBA 32 38 53 68 0.42 VOL 15 04H -0.9 Array WAR TPR 32 39 53 68 0.33 VOL 14 08C -0.98 Array TPR NBC 33 40 52 69 0.11 WAR 10 04H -0.64 Bobbin CBA 33 40 52 69 0.31 VOL 14 04H -0.9 Array WAR TPR 34 41 53 70 0.34 VOL 14 04C -0.9 Array TPR NBC 35 42 39 75 0.15 WAR 13 06C -0.84 Bobbin CBA 35 42 39 75 0.32 VOL 14 06C -1.04 Array WAR TPR 36 43 14 76 0.17 VOL 11 03H 0.64 Array TPR NBC 37 44 38 76 0.22 WAR 17 03C 0.42 Bobbin CBA 37 44 38 76 0.39 VOL 15 03C 0.37 Array WAR TPR 38 45 50 78 0.33 VOL 14 07H -1 Array TPR NBC 39 46 47 86 0.13 WAR 11 02C 0.45 Bobbin CBA 39 46 47 86 0.32 VOL 14 02C 0.31 Array WAR TPR 40 47 24 87 0.19 VOL 11 01C -0.89 Array TPR NBC Page 12 of 17

TABLE 4 Steam Generator 22 TSP Wear TUBE# IND# ROW COL VOLTS IND PCT LOC ELEV PROBE UTIL1 UTIL2 41 48 45 87 0.22 VOL 12 08C -1.02 Array TPR NBC 42 49 46 88 0.28 VOL 13 04H -0.82 Array TPR NBC 43 50 45 90 0.15 WAR 13 05H -0.65 Bobbin CBA 43 50 45 90 0.33 VOL 14 05H -0.93 Array WAR TPR 44 51 44 91 0.25 VOL 12 05H -0.93 Array TPR NBC 45 52 41 93 0.58 VOL 17 05H -0.93 Array TPR NBC 46 53 41 94 0.14 WAR 12 04H -0.65 Bobbin CBA 46 53 41 94 0.48 VOL 16 04H -0.87 Array WAR TPR 47 54 38 97 . 0.15 WAR 13 04H -0.65 Bobbin CBA 47 54 38 97 0.24 VOL 12 04H -0.48 Array WAR TPR 48 55 8 100 0.15 WAR 13 03H -0.7 Bobbin CBA 48 55 8 100 0.34 VOL 14 03H -0.87 Array WAR TPR 49 56 30 102 0.16 WAR 13 04H -0.65 Bobbin CBA 49 56 30 102 0.24 VOL 12 04H -0.93 Array WAR TPR 50 57 27 106 0.22 VOL 12 05C -1.07 Array TPR NBC 51 58 22 107 0.13 WAR 11 . 05H -0.74 Bobbin CBA 51 58 22 107 0.45 VOL 16 05H -0.96 Array WAR TPR 52 59 26 107 0.23 VOL 12 05C -0.93 Array TPR NBC 53 60 13 108 0.26 VOL 13 04C -0.99 Array TPR NBC 54 61 16 111 0.54 VOL 15 05H -0.93 Array TPR NBC 55 62 6 112 0.32 VOL 14 04C -0.9 Array TPR NBC 56 63 6 113 0.14 WAR 12 04H -0.48 Bobbin CBA 56 63 6 113 0.47 VOL 16 04H -0.96 Array WAR TPR Page 13 of 17

TABLE 5 Steam Generator 21 Tube Plugging TUBE# IND# ROW COL VOLTS IND PCT LOC ELEV PROBE UTIL1 UTIL2 1 1 53 45 0.24 VOL 12 AV9 -0.11 Array FLT NBC 1 1 53 45 0.09 VOL 5 AV9 -0.04 +Point' WAR TPR 2 2 45 61 0.19 AVB 6 AV7 0 Bobbin CBA 2 2 45 61 0.86 VOL 20 AV7 -0.35 Array WAR FLT 2 2 45 61 0.24 VOL 12 AV7 -0.29 +Point' WAR FLT Page 14 of 17

TABLE 6 Steam Generator 22 Tube Plugging TUBE# IND# ROW COL VOLTS IND PCT LOC ELEV PROBE UTIL1 UTIL2 1 1 39 57 0.38 VOL 15 AV7 -0.43 Arrav TPR NBC 1 1 39 57 0.13 VOL 5 AV7 -0.22 +Point' WAR FLT 2 2 54 58 0.26 WAR 19 02C 0.39 Bobbin CBA 2 2 54 58 0.58 VOL 17 02C 0.22 Array WAR TPR 2 2 54 58 0.24 VOL 10 02C -0.09 +Point' WAR TPR 3 3 54 59 0.26 WAR 19 02C 0.39 Bobbin CBA 3 3 54 59 0.73 VOL 19 02C 0.06 Arrav WAR TPR 3 3 54 59 0.32 VOL 13 02C -0.11 +Point' WAR TPR 3 4 54 59 0.12 WAR 10 03C -0.82 Bobbin CBA 3 4 54 59 0.55 VOL 17 03C -0.87 Arrav WAR TPR 3 4 54 59 0.15 VOL 7 03C -0.82 +Point' WAR TPR 4 5 55 59 0.26 WAR 19 02C 0.39 Bobbin CBA 4 5 55 59 0.56 VOL 17 02C 0.11 Array WAR TPR 4 5 55 59 0.22 VOL 10 02C -0.07 +Point' WAR TPR 4 6 55 59 0.22 WAR 17 04C 0.37 Bobbin CBA 4 6 55 59 0.79 VOL 20 04C -0.08 Array WAR TPR 4 6 55 59 0.22 VOL 10 04C -0.54 +Point' WAR TPR 5 7 54 61 0.53 WAR 31 01C -0.11 Bobbin CBA 5 7 54 61 1.48 VOL 25 01C -0.73 Arrav WAR FLT 5 7 54 61 0.4 VOL 17 01C -0.57 +Point' WAR FLT 5 8 54 61 0.21 WAR 16 02C 0.42 Bobbin CBA 5 8 54 61 0.66 VOL 18 02C 0.11 Arrav WAR TPR 6 9 54 63 0.27 WAR 20 02C 0.42 Bobbin CBA 6 9 54 63 0.77 VOL 20 02C 0.11 Arrav WAR TPR 6 9 54 63 0.24 VOL 11 02C -0.2 +Point' WAR TPR 7 10 31 104 0.23 WAR 18 05H 0.42 Bobbin CBA 7 10 31 104 0.44 VOL 16 05H 0.25 Arrav WAR TPR 7 10 31 104 0.22 VOL 10 05H 0.18 +Point' WAR TPR Page 15 of 17

e. Number of tubes plugged during the inspection outage for each degradation mechanism, Table 7 provides the number of tubes plugged during 2R29.

TABLE 7 MECHANISM SG 21 SG 22 AVBWear 2 1 TSPWear 0 6

f. The number and percentage of tubes plugged to date, and the effective plugging percentage in each steam generator, and Table 8 provides the total number and percentage of tubes plugged to date.

TABLE 8 PLUGGING SG 21 SG22 TOTAL 2 7 PERCENT 0.04% 0.14%

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

The deepest AVB wear indication reported during 2R29 was 20%TWas reported from the X-Probe TM. The condition monitoring (CM) limit for flat (uniformly deep)

AVB wear is 47.2%TW. As the deepest indication is of lesser depth than the CM limit, CM is satisfied.

The deepest TSP wear indication reported during 2R29 was 25% TWas reported from X-Probe', and is the only TSP wear indication with a flat profile. The flat wear TSP CM limit is 49.5% TW. As the deepest indication is of lesser depth than the CM limit, CM is satisfied.

The deepest TSP wear indication with a tapered profile was 20% TWas reported from X-Probe'. The tapered wear TSP CM limit is 60%TW. As the deepest indication is of lesser depth than the CM limit, CM is satisfied.

Additionally, an operation assessment (OA) was performed that provides reasonable assurance that the performance criteria will not be exceeded during the upcoming operating cycles 29 and 30 until the next planned SG inspection.

Page 16 of 17

LEGEND OF FIELDS AND CODES FIELD EXPLANATION TUBE# Distinct ROW/COL combination within each Table IND# Distinct ROW/COL/LOCATION combination within each Table ROW Row number of tube location COL Column number of tube location VOLTS Measured Voltage IND Three Digit Code - see below PCT Measured percent through wall LOC Location of landmark - see below ELEV Measurement in inches from the center of the landmark to the center of the indication PROBE Probe Coil Type -Array, Bobbin or +Point' UTIL1 Clarifying Codes - see below UTIL2 Clarifying Codes - see below FIELD CODE EXPLANATION IND AVB Anti-Vibration Bar VOL Volumetric WAR Wear LOC O?H  ? = First through Eighth tube support plate on hot leg side AV?  ? =First through Ninth anti-vibration bar O?C  ? =First through Eighth tube support plate on cold leg side UTIL1 CBA Confirmed By Array coil or FLT Flat (non-tapered) wear UTIL2 NBC No Bobbin Call NCA Not Confirmed by Array coil TPR Tapered wear WAR Wear Page 17 of 17

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