ML081560216

Steam Generator Tube Inservice Inspection Report for the 2007 Refueling Outage

ML081560216
Person / Time
Site:	Surry
Issue date:	05/21/2008
From:	Jernigan D Virginia Electric & Power Co (VEPCO)
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
080272
Download: ML081560216 (12)

Text

VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 May 21, 2008 Attention: Document Control Desk Serial No. 08-0272 U.S. Nuclear Regulatory Commission SS&L/TJN R1 Washington, D. C. 20555-0001 Docket No. 50-280 License No. DPR-32 Gentlemen:

VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNIT 1 STEAM GENERATOR TUBE INSERVICE INSPECTION REPORT FOR THE 2007 REFUELING OUTAGE Technical Specification 6.6.A.3 for Surry Power Station Units 1 and 2 requires the submittal of a Steam Generator Tube Inspection Report to the NRC within 180 days after Tavg exceeds 200°F following completion of an inspection performed in accordance with the Technical Specification 6.4.Q, Steam Generator Program.

Attached is the Surry Power Station Unit 1 report for the 2007 refueling outage.

If r~have any questions or require additional information, please contact Mr. Gary D.

i ler at 804-273-2771.

Sin erely, D.E.J ni Site Vice resident Surry Power Station Attachment Commitments made in this letter: None

,46q7

/Qw-

Serial No. 08-0272 Docket No.: 50-280 copy: US Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth Street, S.W., Suite 23T85 Atlanta, Georgia 30303-8931 NRC Senior Resident Inspector Surry Power Station Mr. S. P. Lingam NRC Project Manager - North Anna and Surry U. S. Nuclear Regulatory Commission Mail Stop OWFN 0-8 G9A One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738

Serial No. 08-0272 Docket No.: 50-280 ATTACHMENT 1 SURRY UNIT 1 180-DAY NRC REPORT REGARDING STEAM GENERATOR TUBE INSPECTION PER TECHNICAL SPECIFICATION 6.6.A.3 SURRY POWER STATION UNIT 1 VIRGINIA ELECTRIC AND POWER COMPANY

Serial No. 08-0272 Docket No.: 50-280 SURRY UNIT 1 - FALL 2007 The following satisfies the Surry Power Station Technical Specification (TS) reporting requirement section 6.6.A.3. Bold-italicized wording below represents TS 6.6.A.3 verbiage.

The required information is provided below under each reporting requirement.

A report shall be submitted within 180 days after Tavg exceeds 200°F following completion of an inspection performed in accordance with the Specification 6.4.Q, "Steam Generator(SG) Program."

During the Surry fall 2007 refueling outage, steam generator inspections in accordance with TS 6.4.Q were completed for one of the three steam generators ("B"). This was the initial inspection under the modified Technical Specifications resulting from the TSTF-449 generic specification issued to the industry. Consequently, the referenced outage is the starting point for compliance to the periodicity and tube inspection coverage requirements of TS 6.4.Q Surry Unit 1 Tavg exceeded 200°F on November 28, 2007, therefore 180 days after Tavg exceeded 200°F is May 26, 2008. Effective Full Power Months (EFPM) were 234.4.

The reportshall include:

a. The scope of inspectionsperformed on each SG The following primary side inspections were performed in steam generator "B" (SG- B)

• 100% bobbin probe exam [3048 tubes full Length; 273 tubes straight only in rows 1 through 3 hot leg (H/L) and cold leg (C/L); 188 tubes (u-bends only) rows 2 and 3]

0 669 tubes (20%) +Point probe exam of top of tubesheet H/L [+3"/-3"]

• 669 tubes (20%) +Point probe exam of top of tubesheet C/L [+3"/-3"]

• +Point probe exam of row 1 u-bends [85 tubes from 7C to 7H]

• Miscellaneous +Point probe exams: confirmation/characterization of bobbin indications (non-quantifiable indications, etc) per Dominion Analysis Guidelines; 20% sample of dent related indications; 50% sample of hot leg over expansions (OXPs); largest Cold leg OXPs; other special interest locations. From the OXP through the tube end, including the last 4 inches of the tube on the hot leg, 199 tube ends were inspected, and 11 of these tests were performed on the cold leg.

0 Tubesheet and plug video scan: video examinations of the hot and cold channel head bowls and tubesheets were performed after removal of the diaphragms. Plugs in each leg of this SG were examined visually and revealed no evidence of leakage. No cladding damage or tube end damage was observed and no foreign objects were identified.

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Serial No. 08-0272 Docket No.: 50-280 The following secondary side flushing, lancing and examinations were conducted:

" Upper Bundle Flush (SG- A, B, C)

The bulk of the deposit inventory in these steam generators is known to be located above the top of tubesheet on tubes, supports surfaces, in separators, and on other internal surfaces. In an attempt to reduce the deposit inventory, the upper bundle flush (UBF) process was applied to all three SGs during the outage.

• Flow Distribution Baffle Sludge Lancing (SG- A, B, C)

Following the application of the UBF process, the top surface of the flow distribution baffle (FDB) was cleaned using a 3000 psi, high flow rate static lance. This was the first application of the high pressure, high flow process at Surry. Lancing of the FDB washes deposit material accumulated during UBF down to the tubesheet secondary face where it can be removed by another static lancing application.

0 Top of Tubesheet (TTS) Sludge Lancing (SG- A, B, C)

Top of tubesheet water lancing was performed in all three steam generators using the high pressure, high flow process. The end of cycle (EOC) 21 quantity of sludge removed from each SG is summarized in attached Table 1.

• Top of Tubesheet Cleanliness and FOSAR Examinations (SG- A, B, C)

Post sludge lancing foreign object search and retrieval (FOSAR) examinations were performed in each SG at the top of the tubesheet in the annulus and no-tube lane.

• In-bundle Visual Examinations (SG- A, B, C)

In-bundle visual examinations were also performed in all three SG's to evaluate the effectiveness of the high pressure, high flow lancing process and to determine if the di-methylamine (DMA) soak during shut down helped reduce deposits on the tubesheet.

Although some hard deposits still remain in all three SG's, a significant reduction of the tube collars and the bridging deposits was observed, particularly in SG- A and SG- C.

• Ultrasonic Examination of Feedring (SG- A, B, C)

Selected portions of the feedring for all three steam generators were inspected using ultrasonic examination to allow for continued trending of pipe wall thickness. The data was evaluated and concluded that no condition is expected to develop prior to the next examination which could impair SG tube integrity.

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Serial No. 08-0272 Docket No.: 50-280

b. Active degradationmechanisms found No indication of corrosion degradation was observed during this inspection. Only shallow mechanical damage was reported in four tubes with volumetric degradation above the top of tubesheet on the hot side (attached Table 4), and ten tubes with anti-vibration bar (AVB) wear (attached Table 3).

.Of the four tubes identified in attached Table 4, three are adjacent to each other and their damage is attributed to historical foreign object wear (no object was immediately adjacent to these tubes during this inspection). Two of the three indications were detectable in 1998 and have not changed since that time. The third indication could not be detected with the technique used in 1998 but was likely caused by the same foreign object. The fourth indication (Row 1 Col 7) is attributed to a previous SG maintenance process such as sludge lancing or secondary side inspection. No foreign objects remain adjacent to any of the affected tubes and none of the indications exceeded the Technical Specification plugging limit.

The largest AVB wear flaw identified during this examination was only 22 % through-wall (TW).

Two shallow AVB wear indications reported during this inspection were not reported during the previous inspection. Historical data reviews confirmed that the indications were present previously, but were below the reporting criteria, hence they are not new flaws. The growth rate of AVB wear continues to decline and no newly initiated AVB wear was identified. No tubes required plugging due to AVB wear during this outage.

The secondary side inspections indicated no component degradation that would compromise tube integrity.

c. Nondestructive examination techniques utilized for each degradationmechanism Inspections focused on the degradation mechanisms listed in attached Table 2 utilizing the referenced eddy current techniques.

d. Location, orientation(if linear), and measured sizes (if available) of service induced indications As stated in the (b) response above, several wear type indications were noted. Attached Tables 3 and 4 provide the detailed information regarding these indications.

e. Number of tubes plugged during the inspection outage for each active degradation mechanism A number of tubes were found to contain permeability variation (PVN) signals. PVN signals are important because they Can interfere with degradation signals. The PVNs were re-examined with +Point probes and in some cases with magnetically biased +Point probes to suppress the signal and allow the underlying tube material to be properly examined. No degradation was identified. In one tube however, the PVN signal could not be adequately suppressed to ensure Page 3 of 9

Serial No. 08-0272 Docket No.: 50-280 a high quality inspection and the tube was preventively plugged. Attached Table 5 provides the detailed information regarding the tube which was plugged.

f. Total number and percentage of tubes plugged to date Attached Tables 6 and 7 provide the plugging attributes and the percentage of tubes plugged to date.

g. The results of condition monitoring,including the results of tube pulls and in-situ testing The Condition Monitoring evaluation was based upon fall 2007 examination results for SG- B.

All reported degradation falls below the applicable condition monitoring limit (i.e. 66.4% for bounding 0.6" long 360 degree volumetric degradation) and therefore satisfies the Technical Specification structural performance criteria. This provides reasonable assurance that none of these volumetric flaws would have leaked during a main steam line break, thereby satisfying the accident leakage performance criteria. Since this conclusion could be reached analytically using NDE inspection results with a full accounting of significant uncertainties, no in-situ pressure testing was required to demonstrate structural and leakage integrity. During the past operating cycle, no measurable primary-to-secondary leakage was observed, thereby satisfying the operational leakage performance criteria.

The results of the 2007 inspection and the condition monitoring conclusions confirm that the 2006 operational assessment was appropriately bounding. No tubes were removed from the SG for destructive examination.

h. The effective plugging percentage for all plugging in each SG There are no sleeves installed in the Surry Unit 1 steam generators therefore, the effective plugging percentage remains the same as stated in (f) above.

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Serial No. 08-0272 Docket No.: 50-280 Table 1- Sludge Removal Summary EOC 21 Steam Generator Quantity Removed (Ibs)

A 55.5 B 53.5 C 101.5 Table 2 - Inspection Method for Applicable Degradation Modes Classification Degradation Location Probe Type Mechanism Potential Tube Wear Anti-Vibration Bars Bobbin - Detection Bobbin and +PointTM _Sizing Potential Bobbin and +Pointm - Sizing Tube Wear Flow Distribution Baffle BbiBobbinn - PitM Detection-Szn Bobbin - Detection Existing Tube Wear Tube Support Plate Bobbin and +Point _ Sizing Potential Tube Wear T Straight Leg &AVB Tangents Bobbin Bobbin - Detection or +PointTM - Sizing Tube Wear (foreign Bobbin - Detection Existing objects) Freespan and TTS +PointmM- Sizing Potential Hot Leg Top-of- Bobbin and +PointTM - Detection ODSCC Tubesheet Sludge Pile onM Area +Point Sizing Hot Leg Top-of-Tubesheet Sludge Pile Relevant/Informational PWSCC Area and +PointTM - Detection and Sizing Inspection Within Tubesheet Anomaly locations Relevant/Informational ODSCC Row 1 U-bends +PointTM - Detection and Sizing Inspection PWSCC R 1 Relevant/Info rmational ODSCC Freespan and Tube TM Inspection Supports +PointT- Detection and Sizing Relevant/Informational OD Pitting Top-of-Tubesheet Bobbin and +Point - Detection Inspection +Point TM - Sizing ODSCC- outside diameter stress corrosion cracking PWSCC- primary water stress, corrosion cracking Page 5 of 9

Serial No. 08-0272 Docket No.: 50-280 Table 3- Surrv 2007 Inslection Summary - AVB Indication Comparison of 2003 and 2007 AVB Wear Depths - Surry Unit 1 - SG B Location (inch) Depth (%TW) Upper Bound Projected 2010 (ETSS 96004.1) 2007 Depth Depth (%TW)

SG Row Col AVB No. 2003 2007. 2003 2007 (%TW) (for CM) (for OA)

B 26 61 AV3 0.00 -0.02 13 11 28 39 B 32 26 AV3 - 0.00 - 10 27 38 B 34 58 AV2 0.00 0.00 22 22 39 50 B 34 58 AV3 0.00 0.00 17 17 34 45 B 34 58 AV4 0.00 - 10 - -

B 35 17 AV2 -0.03 0.07 12 10 27. 38 B 35 17 AV3 0.00 0.05 17 20 37 48 B 35 18 AV2 -0.05 - 13 - -

B 38 21 AV1 0.27 0.27 13 13 30 .41 B 38 21 AV2 0.24 12 - -

B 38 22 AV2 0.19 - 10 - -

B 38 22 AV3 - -0.12 - 9 26 37 B 39 25 AV3 0.00 10 - -

B 40 25 AV2 0.00 0.00 19 21 38 49 B 41 27 AV2 0.00 0.00 .12 11 28 39 B 41. 27 AV3 0 0 13 8 25 36 B 42 29 AV2 0 0 16 15 32 43 B 42 30 AV4 -0.22 -0.1 12 10 27 38 ETSS- examination technique specification sheets CM- condition monitoring OA- operational assessment Notes

• SG-B Number of Tubes With AVB Indications Reported in 2007: 10

• SG-B Number of New Indications Not Present Previously Based on Historical Lookups: 0

• SG-B Average Wear Rate Prior to This Outage (%TW/Cycle): 1.66 (41 points)

• SG-B Average Wear Rate Including This Outage (%TW/Cycle): 1.41 (54 points)

• 95/50 Wear Rate Based on Unit 1 Current & Historical Data: 5.77 %TW/Cycle

• Total Random Sizing Uncertainty at 95/50: 13.7 %TW

• Upper Bound 2007 Depth: [0.97] x [Field Call] +

[3.49] + [13.7]

• Fall 2010 Projected Depth: [Upper Bound 2007 Depth] + (5.77

%TW/Cycle) x 2 Cycles]

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Serial No. 08-0272 Docket No.: 50-280 Table 4 - Summary of Non-AVB Wear Volumetric Degradation Identified ETSS 21998.1 ETSS 27901.1 Foreign Axial Circ. Max Depth Max Depth Object In-Situ SG Row Col Location Length (Ln) Length (in (%TW) (%TW) Comments Present Previously Remaining? Tested? Plugged?

Visually observed mechanical damage. Mechanical 1 7 TSH+0.22" 0.90 0.34 26 na damage also visible at same location on the cold side but probe data or 2003 No No No too shallow to detect with +Point. May have been caused by a previous SG maintenance activity.

Yes, RPC 1998, no B 40 50 TSH+0.32" 0.30 0.45 30 36 change. Not visible in No No No bobbin data Damage is attributed to historical foreign object wear.

No object was found immediately adjacent to these Yes, RPC 1998, no B 40 51 TSH+0.35" 0.35 0.42 29 36 tubes during this inspection. Other objects were change. Not visible in .to No No observed and removed from the general vicinity of bobbin data these tubes. Not visible in 1998 or B 41 51 TSH+0.19" 0.35 0.34 26 28 2003 bobbin probe No No No data. (No RPC)

TSH- top of tube sheet 0

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Serial No. 08-0272 Docket No.: 50-280 Table 5 - Steam Generator Tube Plumged During EOC21 AA .Surry Unit I - EOC211REOC16 - SIG 1B PLUG LIST (Rev. 0)

AkFR E XAI Tube SIG Row Cot Hot LeO Cold Log Reason for Tube Repair oty. Stab Rev.

SURRY1B 11 88 ROLLED ROLLED PVN@ 2C+42.64 1 NO 0 Totals: 1 0 Notes (Rev. 0):

1. All tubes shall be plugged using a .875 Threaded Roll Plug Assembly. LOPE Finger - part number 1222366-004.

2. The tubes on the above list have been reviewed for skip rolls, over expansions, dents, bulges and additional indications.

No such anomalies or indication that would prohibit installation of the plugs were detected.

3. The indications in the tubes on the above list have been screened against the in situ screening criteria.

4. The indications identified on this list as requiring plugging are consistent with those specified in the Analysis Guidelines and include: AVB Wear -= 30%, OBS, MAI, MCI, MVI, PVN. SAI, SCI, (SVI and VOL -= 40% or with PLP).

5. All planned eddy current examinations for these tubes have been successfully completed and confirmed by Data Management Personnel.

Approvals:

": Vii Armentrout. Fleet SG Program Owner, Dominion

'07 Cb~onWirt, AREVANP Data Manageme Todd Mayer, Surry SG Program Owner, Dominion S

t e tory, AREVA I*P.ad Analyst 11/312007 8:24 PM Pugt I fi Page 8 of 9

Serial No. 08-0272 Docket No.: 50-280 Table 6- Plugging Attributes SURRY POWER STATION UNIT #1 PLUGGING ATTRIBUTES DATE Preservice Mar-83 Nov-84 Jun-86 Apr-88 Oct-90 Mar-92 Feb-94 Oct-95 E-FPY 0 1.3 2.3 3.4 4.7 6 7.1 8.7 10.1 S/G AVAP*B*Z::C A .B-jBC;..AB9 C A ,". A .1B1:3C. .A1jB. . C A .B. C A B .C AVB 1 4 1 Freespan 1 Tube Pulls 1 2 Foreign Object Pitting Anomalies Other 1 1 3 1 2 1

[Sub-Total Il1 110110 10 10 3 1 11 01212101010100 212 010 0o 410 0 0 1]

[TOTAL 2 1 0 4 [ 4 0 2 j 2 j 4 1 I DATE Mar-97 Oct-98 Apr-00 Oct-01 Apr-03 Nov-04 Apr-06 Oct-07 Total per SIG EFPY 11.4 12.7 14.1 15.5 16.8 18.2 19.5 S/G *JA* B C A CA A>;B*:B ",A: B C A*B; C A B C A B C'A *B C A BC AVB 1 8 2 1 4 4 10 Freespan 1 0 0 Tube Pulls 0 0 3 Foreign Object 3 6 2 6 3 2 Pitting 0 0 0 Anomalies 0 0 0 Other 4 3 3 7 4 7 1 18 15 5 Sub-Total 5 10 0 0 6 0 0 10 18 5 10 10 01 7 4 0 0 10 131 0 13 10 1 110 29 12220 TOTAL 5 6 8 5 11 0 16 1 71 I Total tubes plugged by category 18 AVB 1 Freespan 3 Tube Pulls 11 Foreign Objects 0 Pitting 0 Anomalies 38 Other EFPY- effective full power years Table 7 - Tube Plugging Summary Tubes Installed Tubes Plugged To-Date SG "A" 3,342 29 (0.9%)

SG ý"B" 3,342 22 (0.7%)

SG "C" 3,342 20 (0.6%)

Total 10,026 71 (0.7%)

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