NL-10-1871, Unit 2 - Fourteenth Maintenance/Refueling Outage - Steam Generator Tube Inspection Report

Unit 2 - Fourteenth Maintenance/Refueling Outage - Steam Generator Tube Inspection Report

ML102710369
Person / Time
Site:	Vogtle
Issue date:	09/28/2010
From:	Ajuni M Southern Nuclear Operating Co
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
NL-10-1871
Download: ML102710369 (8)

Text

Mark J. Ajluni, P.E. Southern Nuclear Nuclear Licensing Director Operating Company, Inc.

40 Inverness Center Parkway Post Office Box 1295 Birmingham, Alabama 35201 Tel 205992.7673 Fax 205.992.7885 September 28,2010 SOUTHERN'\

COMPANY Docket Nos.: 50-425 NL-10-1871 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Vogtle Electric Generating Plant - Unit 2 Fourteenth Maintenance/Refueling Outage Steam Generator Tube Inspection Report Ladies and Gentlemen:

In accordance with the requirements of Vogtle Electric Generating Plant Technical Specification 5.6.10, Southern Nuclear Operating Company submits this report of the steam generator tube inspections performed during the Unit 1 Fourteenth maintenance/refueling outage (2R14). Entry into Mode 4 occurred on April 2, 2010.

This letter contains no NRC commitments. If you have any questions, please contact Jack Stringfellow at (205) 992-7037.

Respectfully submitted, M. J. Ajluni Nuclear Licensing Director .

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MJAfTAH/lac

Enclosure:

VEGP 2R 14 Steam Generator Tube Inspection Report

u. S. Nuclear Regulatory Commission Log: NL-10-1871 Page 2 cc: Southern Nuclear Operating Company Mr. J. T. Gasser, Executive Vice President Mr. T. E. Tynan, Vice President - Vogtle Ms. P. M. Marino, Vice President - Engineering RType: CVC7000 U. S. Nuclear Regulatory Commission Mr. L. A. Reyes, Regional Administrator Mr. R. E. Martin, NRR Project Manager - Vogtle Mr. M. Cain, Senior Resident Inspector - Vogtle Mr. P.G. Boyle, NRR Project Manager

Vogtle Electric Generating Plant - Unit 2 Fourteenth Maintenance/Refueling Outage Steam Generator Tube Inspection Report Enclosure 2R14 Steam Generator Tube Inspection Report

2R14 STEAM GENERATOR TUBE INSPECTION REPORT Introduction The 2R14 outage was conducted after cumulative service equivalent to - 18.5 EFPY (effective full power years); the Cycle 14 power generation was -1.33 EFPY. Analyses based on conservative assumptions used in the Condition Monitoring and Operational Assessments demonstrated that there were no tubes that exceeded the Reg. Guide 1.121 and NEI-97-06 Revision 2 criteria for tube integrity during Cycle 14. The eddy current inspections were performed by the Steam Generator Maintenance Services Group of the Westinghouse Nuclear Services Division. Secondary data analysis was performed by NDE Technology under direct contract with Southern Nuclear. Two tubes (R40C58 and R52C73) in SG2 were plugged due to anti-vibration bar (AVB) wear that exceeded the Technical Specifications (TS) plugging criteria.

No tubes required In-Situ pressure testing. The H* Alternate Repair Criteria was approved for Cycle 15 operation; therefore, tube end +Point inspections below top of tubesheet (TIS) -13.1" were omitted for 2R14 and the TIS inspection samples ranged from TIS +3" to TIS -13.1".

2R14 Scope The scope for 2R14 consisted of the inspections listed below. The inspection program, in accordance with Revision 7 of the EPRI PWR SG Examination Guidelines, addressed the known degradation mechanisms observed in Vogtle Unit 2 in prior inspections, as well as those regarded as potential degradation mechanisms.

• 100% Bobbin examination of tubes in SGs 2 and 3, except for Rows 1 and 2, which are inspected from tube end to TSP#7 from both HL and CL.

• 50% +Point examination of small radius U-bends (Row 1 and Row 2) in SGs 2 and 3, including all Row 1 and Row 2 tubes that were not +Point inspected in the U-bend during 2R12.

• +Point examination of Special Interest, HL and CL, of bobbin possible flaw locations including U-bends.

• Tubes indicating Seabrook-type U-bend offset behavior, with DSls (TSP indications) that are not confirmed, will nonetheless be preventively plugged.

• 50% +Point examination of expanded tubesheet section BLGs and OXPs in the region TSH +3 inches to the H* depth of TSH -13.1 inches. The sampled extents in SG2 and SG3 for this inspection program include all BLG and OXP locations in this elevation range which were not tested during the 2R12 outage. These tubes are included in the 50% H* length +Point program.

BLG = differential mix diameter discontinuity signal within the tubesheet of 18 volts or greater as measured by bobbin coil probe; OXP =a tube diameter deviation within the tubesheet of 1.5 mils or greater as measured by bobbin coil profile analysis.

• 50% +Point examination at HL tubes from TSH +3" down to the licensed H* depth at TSH -13.1 inches.

• +Point examination of 100% of dents and dings 2:2 volts in HL straight lengths of SG2 and SG3, with the total number of inspected dents and dings to comprise no less than 25% of the total dents and dings 2:2 volts in Vogtle Unit 2 SGs, and with any makeup which is required to meet the 25% quantity being selected from U-bends.

• Visual inspection of tube plugs in SGs 2 and 3.

• Slippage monitoring in accordance with regulatory requirements for the licensing of H*.

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Vogtle Electric Generating Plant - Unit 2 2R14 Steam Generator Tube Inspection Report Degradation Mechanisms Found and NDE Techniques Utilized Wear at AVBs is the only continuing degradation mechanism in the Vogtle 2 SGs. The bobbin probe, which is qualified for detection and sizing of AVB wear by ETSS 96004.1 Revision 12, was used to evaluate this degradation.

Service Induced Indication Descriptions Volumetric The following Volumetric Indication was seen during 2R14:

V ogteI 2V o Iumetnc. Ind"Icatlon f or 2R14 SG Row Col Volts %TWD Locn 3 1 112 0.28 21 TSC+18.2" 1

TSC - Tubesheet region on CL Side.

The indication in SG3 R1C112 was determined to be a historical indication that originated from interaction with sludge lance equipment prior to 2004 (2R10). No PLP indication was associated with this location.

Ava Wear AVB wear continued to be identified in Vogtle 2R14 in SG2 and SG3. Tube locations where AVB wear was identified are provided in the tables below for each SG:

Vog tl e 2R14 SG2 AVB Wid" ear n Ica f Ions Row Col Location' 2R14 %TWD Row Col Location' 2R14%TWD 29 10 AV5 10 52 73 AV2 13 34 12 AV3 6 52 73 AV3 33 36 14 AV4 8 52 73 AV4 46 38 15 AV2 10 52 73 AV5 29 38 15 AV3 13 52 73 AV6 32 36 16 AV6 10 38 74 AV2 12 42 19 AV2 12 38 74 AV3 14 42 19 AV3 14 38 74 AV4 13 42 19 AV4 14 38 74 AV5 8 42 19 AV5 14 38 74 AV6 7 43 20 AV1 8 42 74 AV2 27 43 20 AV2 13 42 74 AV3 24 49 32 AV4 12 42 74 AV4 9 38 39 AV2 9 42 74 AV5 7 38 39 AV3 14 42 74 AV6 10 38 39 AV4 13 49 74 AV3 19 38 39 AV5 20 51 74 AV3 18 56 41 AV3 13 51 74 AV4 10 39 43 AV2 21 51 74 AV5 8 39 43 AV3 19 51 74 AV6 7 39 43 AV4 14 57 79 AV3 9 39 43 AV5 14 57 79 AV4 12 39 43 AV6 10 38 81 AV2 11 56 43 AV6 13 38 81 AV5 12 39 44 AV3 16 38 81 AV6 15 39 44 AV5 10 56 82 AV5 11 Page 2 of 5

Vogtle Electric Generating Plant - Unit 2 2R14 Steam Generator Tube Inspection Report 1 AV# - Location of AVB intersection with the tube (up to 6)

Vogtle 2R14: SG2 AVe Wear Indications (continued)

Row Col Location' 2R14% TWO Row Col Location 2R14% TWO 39 44 AV6 9 55 84 AV1 10 38 45 AV1 11 55 84 AV4 11 40 48 AV4 20 54 86 AV4 10 40 48 AV5 11 51 87 AV2 29 45 49 AV3 13 51 87 AV3 29 57 49 AV6 12 51 87 AV4 23 42 50 AV2 16 51 87 AV5 31 42 50 AV3 11 39 88 AV4 11 42 50 AV4 13 42 88 AV2 10 39 52 AV4 16 53 88 AV4 12 40 52 AV3 23 53 88 AV5 19 52 52 AV3 10 50 89 AV3 11 53 52 AV3 11 50 89 AV4 14 56 52 AV3 12 50 89 AV5 10 40 54 AV3 15 50 89 AV6 13 48 56 AV3 12 51 89 AV3 12 59 56 AV4 15 51 89 AV4 33 40 58 AV1 14 51 89 AV5 28 40 58 AV2 29 51 89 AV6 17 40 58 AV3 35 51 90 AV4 15 40 58 AV4 19 51 90 AV5 14 40 58 AV5 45 53 90 AV4 11 40 58 AV6 13 53 90 AV6 10 40 63 AV3 12 49 91 AV2 22 43 64 AV1 18 49 91 AV3 12 49 66 AV2 19 50 91 AV4 8 49 66 AV3 17 51 91 AV3 10 50 70 AV4 16 51 91 AV4 14 58 70 AV2 13 51 91 AV5 19 51 71 AV6 9 51 91 AV6 17 44 72 AV5 15 52 91 AV4 14 51 72 AV2 9 38 100 AV3 13 51 72 AV3 9 36 106 AV3 9 51 72 AV4 8 36 106 AV4 13 51 72 AV5 9 36 106 AV5 10 57 72 AV1 13 36 106 AV6 13 57 72 AV3 11 39 107 AV2 11 40 73 AV5 14 28 115 AV1 12 40 73 AV6 12 28 115 AV6 18 43 73 AV4 21 12 121 AV6 8 1 AV# - Location of AVB intersection with the tube (up to 6)

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Vogtle Electric Generating Plant - Unit 2 2R14 Steam Generator Tube Inspection Report VOg tl e 2R14 SG3 AVB Wid" ear n Icatlons Row Col Location 2R14% TWD Row Col Location 2R14% TWD 32 12 AV2 13 57 62 AV4 13 32 12 AV5 19 35 64 AV4 5 34 13 AV5 18 42 64 AV1 6 41 19 AV4 13 42 64 AV2 18 42 20 AV3 13 42 64 AV3 12 42 20 AV4 13 42 64 AV4 27 44 23 AV3 12 42 64 AV5 16 50 29 AV4 11 44 64 AV4 6 48 37 AV3 15 44 68 AV3 6 51 38 AV5 9 39 72 AV2 18 54 38 AV5 16 39 72 AV3 21 57 48 AV4 16 39 72 AV4 21 57 48 AV5 15 41 77 AV3 12 57 48 AV6 15 41 77 AV4 27 57 49 AV4 11 41 77 AV5 25 58 49 AV1 14 57 78 AV2 11 58 49 AV5 12 56 82 AV2 26 58 49 AV6 11 56 82 AV3 37 42 53 AV4 7 56 82 AV4 22 43 62 AV4 9 52 83 AV2 17 45 62 AV4 10 52 83 AV3 28 46 62 AV4 12 52 83 AV4 23 53 62 AV3 12 52 83 AV5 22 53 62 AV5 6 30 112 AV5 13 54 62 AV2 7 12 121 AV1 10 AV# - Location of AVB mtersectlon with the tube (up to 6)

Tube Plugging The following table contains all SG tubes plugged in Vogtle 2R14 and the related degradation mechanism.

2R14 Pluaaed Tubes (2)

SG Row Col Degradation Mechanism 2 40 58 AVB Wear> 40%TW 2 52 73 AVB Wear> 40%TW Total plugging in the SGs after 2R14 is as follows:

SG 1 - 6 tubes for a total of 0.11 % tubes plugged SG 2 -14 tubes for a total of 0.25% tubes plugged SG 3 - 4 tubes for a total of 0.07% tubes plugged SG 4 - 21 tubes for a total of 0.37% tubes plugged Page 4 of 5

Vogtle Electric Generating Plant - Unit 2 2R14 Steam Generator Tube Inspection Report Secondary Side Inspections Sludge lancing and FOSAR was performed in all four steam generators. 35 total Ibm of sludge was removed. An upper bundle in-bundle (UBIB) inspection was performed in SG2 with no abnormal observations.

Condition Monitoring Conclusions Upon completion of the scheduled +Point programs for the tubesheet H* region, the top of the tubesheet, the BLG/OXP population, DNG/DNT locations, and small radius U-bends, no indications were found to exceed the NEI 97-06 performance criteria specified in the Degradation Assessment. This is inclusive of +Point testing of I-code indications.

The volumetric indication seen in 2R14 was determined, by history review, to be from interaction with sludge lancing equipment.

None of the AVB wear indications in either SG2 or SG3 exceed the NEI 97-06 performance criteria given in the 2R14 Degradation Assessment. Two tubes were plugged due to AVB wear indications that exceeded the Technical Specifications plugging criteria.

No secondary side tube damage attributable to foreign objects was identified from the FOSAR and visual inspections.

Given the absence of operating leakage during Cycle 14, it is concluded that there was no leakage from plugs. This is consistent with the video inspection of the tube plugs which produced no exceptions to expected conditions.

Slippage Monitoring was performed in accordance with regulatory commitments for licensing of the H* Alternate Repair Criteria. Analysis for tube slippage associated with Slippage Analysis Signal (SVR) was completed for all tubes in SG2 and SG3. No SVR signals were observed.

No In-Situ tests or tube pulls were required to demonstrate tube integrity.

Evaluation of the indications found in the 2R14 inspections confirms that the tube integrity structural and leakage performance criteria condition monitoring requirements as specified in NEI-97-06 Revision 2 are satisfied.

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