NL-11-1904, Unit 1 Sixteenth Maintenance/Refueling Outage Steam Generator Tube Inspection Report
| ML112650199 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 09/21/2011 |
| From: | Ajluni M Southern Nuclear Operating Co |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| NL-11-1904 | |
| Download: ML112650199 (11) | |
Text
Mark J. Ajluni, P.E.
Southern Nuclear Nuclear Licensing Director Operating Company, Inc.
40 Inverness Center Parkway Post Off ice Box 1295 Alabama 35201 Tel 205.992.7673 Fax 205.992.7885 September 21, 2011 SOUTHERN'\\'
COMPANY Docket Nos.: 50-424 NL-11-1904 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Vogtle Electric Generating Plant - Unit 1 Sixteenth 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 sixteenth maintenance/refueling outage (1R16). Entry into Mode 4 occurred on March 29,2011.
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 MJAlRMJ/lac
Enclosure:
1R16 Steam Generator Tube Inspection Report cc:
Southern Nuclear Operating Company Mr. S. E. Kuczynski, Chairman, President & CEO 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. V. M. McCree, Regional Administrator Mr. P. G. Boyle, NRR Project Manager - Vogtle Mr. L. M. Cain, Senior Resident Inspector - Vogtle
Vogtle Electric Generating Plant - Unit 1 Sixteenth Maintenance/Refueling Outage Steam Generator Tube Inspection Report Enclosure 1R16 Steam Generator Tube Inspection Report
Enclosure Vogtle Electric Generating Plant - Unit 1 1 R16 Steam Generator Tube Inspection Report Introduction The 1R16 outage was conducted after cumulative service equivalent to -21.2 EFPY (effective full power years); the Cycle 16 power generation was -1.4 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 or NEI-97-06 Revision 2 criteria for tube integrity during Cycle 16.
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. One tube (R26 C110) in Steam Generator 1 (SG1) was plugged due to loose part wear that exceeded the Technical Specifications (TS) plugging criteria. One tube (R8 C57) was plugged in SG4 due to an outer diameter (00) axial crack signal below the bottom of the tube expansion transition. Criteria for in-situ testing were not met for either tube.
The H* Alternate Repair Criteria was approved by the NRC for implementation during 1 R 16 (ML110660264). Therefore, tube end +Point inspections below top of tubesheet (TTS) -15.2 inches were omitted, and the TIS inspections ranged from TTS +3 inches to TTS -15.2 inches.
1R16 Scope The scope for 1 R16 involved the scheduled inspections listed below. The inspection program, required by Revision 7 of the EPRI PWR SG Examination Guidelines, addressed the known degradation mechanisms observed in Vogtle Unit 1 in prior inspections, as well as those regarded as potential degradation mechanisms.
- 100% Bobbin examination of tubes in SGs 1 and 4, except for Rows 1 and 2, which are inspected from tube end to tube support plate (TSP) #7 from both hot leg (HL) and cold leg (CL).
- 100% +Point examination of Row 1 and Row 2 U-bends from the top TSP on the HL to the top TSP on the CL in all SGs.
- +Point examination of Special Interest, HL and CL, of bobbin possible flaw locations including U-bends.
- 100% +Point examination at HL tubes in all SGs from the top of tubesheet (TTS) to the licensed Temporary Alternative Repair Criteria (TARC) depth for H* (tubesheet region on HL side (TSH) +3/-15.2 inches). This inspection captured 100% of the TTS and BLGI OXP populations, as defined below, along with the required periodic sample specified in the regulatory approval of TARC.
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.
- 25% +Point examination of SG1 and SG4 CL tubes TIS +3 inches to -3 inches. This inspection was aimed at early warning awareness of TTS degradation mechanisms and was analogous to a similar inspection that was performed in SG2 and SG3 during 1 R 15.
- +Point examination of 25% of dents and dings 2! 2 volts in HL straight lengths and U bends of all SGs.
- Visual inspection of tube plugs in all 4 SGs.
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Enclosure Vogtle Electric Generating Plant - Unit 1 1 R16 Steam Generator Tube Inspection Report Damage Mechanisms Found and NDE Techniques Utilized All of the damage mechanisms found during 1 R 16 inspections were identified in previous inspections and in the 1 R16 SG Degradation Assessment.
Mechanical Wear due to a foreign object was found in all SGs. +Point and bobbin techniques were used to evaluate the wear.
Mechanical Wear at anti-vibration bars (AVBs) were found in SGs 1 & 4. Bobbin technique was used to evaluate the wear.
- A single axial outer diameter stress corrosion cracking (ODSCC) indication was found in SG4. +Point probe techniques were used to analyze the indication.
Service Induced Indication Descriptions Foreign Object Wear The foreign object wear (PCT) identified in SG1 R26 C110 is a new indication located at the TSP 2H-0.23 inch. The tube was plugged based on the 40% through wall (% TW)
Technical Specification plugging limit. The +Point % TW depth did not exceed the threshold for proof testing and the bobbin voltage did not exceed the threshold for leak testing; therefore, in-situ testing was not required to demonstrate tube integrity. The loose part could not be verified visually; however, a boundary, 2 tubes deep, was inspected around R26 C110 using +Point testing. There was no evidence of wear on the boundary tubes and no possible loose part (PLP) indications.
PCT indications near the TTS in SG1 Rows 39 and 41 from Columns 100 to 103 were reported in previous outages. The indications exhibited almost zero growth in 1 R16 and remain in service.
The legacy indication at R30 C111 was examined using +Point techniques and remained unchanged.
One volumetric indication was found just above TTS on the CL. +Point testing determined there is a 27% TW wear indication. Bobbin data from 1 R14 and 1 R16 was analyzed. It was concluded the bobbin probe signal was obscured in the expansion transition, and the flaw may have existed at the 1 R14 inspection.
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Enclosure Vogtle Electric Generating Plant - Unit 1 1R16 Steam Generator Tube Inspection Report Tab e 1: Vogtle 1 PLP/PCT for 1 R16 SG Row Col Volts Ind
%TW0 7
Locn 1
14 112 0.38 PLp5 TSH!
1 15 112 0.27 PLP TSH i
1 25 8
0.15 PLP TSH I
1 25 9
0.15 PLP TSH 1
26 110 i
0.66 Pcr 42 2H2 1
36 87 0.47 PLP TSH 1
36 88 0.51 PLP TSH 1
39 100 0.13 PCT 14 TSH 1
41 97 0.32 PCT 27 TSC3 i
1 41 100 0.17 PCT 17 TSH 1
41 I
100 0.46 PCT 34 TSH 1
41 101 0.29 PCT I
25 TSH I
1 41 102 0.22 PCT 21 TSH 1
41 103 0.25 PCT 23 TSH 2
18 8
0.09 PLP TSH I
2 19 8
0.08 PLP TSH I
2 35 106 I 0.15 PLP TSH 2
36 106 0.13 PLP TSH 3
23 97 0.31 PLP TSH 3
30 111 1.74 PCT I
29 BPH 4
4 30 18 0.25 PLP TSH I
4 30 18 0.08 PLP TSH i
4 31 18 0.4 PLP TSH 4
31 18 0.48 PLP TSH 4
i 38 104 0.13 PCT 12 BPH TSH - Tubesheet region on HL Side.
2 2H Tube Support Plate 2 on HL side 3 TSC - Tubesheet region on CL side 4 BPH - Flow distribution baffle plate (FOB) on HL side 5 PLP - Possible Loose Part 6 PCT Foreign Object Wear 7%TWO - Percent Through-wall Depth AVBWear AVB wear continued to be identified in Vogtle -IR16 in SG1 and SG4. AVB wear identified is provided in the following tables.
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Enclosure Vogtle Electric Generating Plant - Unit 1 1 R16 Steam Generator Tube Inspection Report Ogl e SG1 AVB Wid" ear Ica Ions Table 2 V tl 1R16 "
n f
Row Col Location1 1R16 % TW Row Col Location1 1R16% TW 23 40 AV6 11 42 43 AV5 14 23 116 AV6 10 42 43 AV3 12 24 116 AV6 13 42 43 AV2 11 26 116 AV6 19 43 21 AV5 27 26 116 AV1 12 43 21 AV4 22 27 100 AV5 11 43 21 AV6 12 27 115 AV6 15 43 21 AV2 10 27 115 AV1 14 43 81 AV4 13 281 115 AV6 32 43 81 AV5 8
28 115 AV1 17 43 82 AV3 14 32 1liA I
AV6 14 43 83 AV4 20 34 107 AV3 16 43 83 AV2 15 34 107 AV1 12 43 83 I
AV5 12 35 16 AV4 13 43 83 AV1 11 35 18 AV6 11 43 83 AV3 9
35 34 AV4 11 43 85 AV2 10 35 34 AV3 10 43 91 AV2 30 35 104 AV3 14 43 91 AV3 18 35 104 AV4 13 43 91 AV4 14 36 105 AV3 11 44 21 AV5 15 37 77 AV3 11 44 80 AV4 11
~-
I 102 AV5 21 44 80 AV5 10 38 16 AV4 32 44 80 AV3 9
c---.........
38 16 AV2 16 44 102 AV2 13 38 16 AV3 15 45 30 AV3 14 38 16 AV5 11 45 90 AV2 14 38 108 I AV1 12 45 90 AV3 10 38 108 AV6 12 46 41 AV1 10 48 AV3 21 47 99 AV2 13 39 48 AV4 21 48 97 AV1 14 39 48 AV5 14 49 88 AV4 9
39 48 AV2 12 50 29 2
11 39 87 AV4 11 50 29 AV1 10 39 90 AV3 11 52 33 AV2 17 39 90 AV2 10 52 33 AV3 17 39 104 AV4 12 52 39 AV3 27 40 20 AV4 10 52 39 AV4 27 AV2 21 40 34 AV4 16 52 39 I
40 34 AV3 10 52 39 AV5 12 1 AV# - Location of AVB intersection with the tube (there are up to 6)
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Enclosure Vogtle Electric Generating Plant - Unit 1 1 R16 Steam Generator Tube Inspection Report Table 2: Vo tie 1R16: SG1 AVB Wear Indications (continued Row Col Location1 1R16 %TW Row Col Locat 40 34 AV6 9
52 44 40 34 AV2 8
52 91 40 47 AV4 34 53 39 40 47 AV3 32 53 43 AV2 10 40 47 AV6 12 53 43 AV5 9
40 47 AV5 10 53 87 AV3 10 40 62 AV3 13 53 90 AV6 16 40 62 AV5 10 54 36 AV2 11 40 75 AV3 54 37 AV1 12 40 54 37 AV6 12 40 54 45 AV2 10 40 15 54 53 AV2 10 41 18 AV6 14 54 83 AV1 11 41 18 AV4 11 54 83 AV6 11 41 18 AV5 10 57 45 AV3 41 23 AV4 10 57 45 AV2 41 34 AV4 10 57 45 AV6 41 44 AV3 34 57 45 AV5 41 44 AV2 19 57 78 41 51 AV4 12 58 75 41 80 AV3 58 76 42 34 AV4 59 62 42 37 AV6 1
42 43 AV4 1
1 AV# - Location of AVB intersection with the tube (there are up to 6)
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Enclosure Vogtle Electric Generating Plant - Unit 1 1 R16 Steam Generator Tube Inspection Report Table 3: Vog tl 1R16 SG4AVBWear Ind" f
e Ica Ions Row Col Location' 1R16 Row Col Location 1
1R16
%TW
%TW 27 8
AV6 14 40 84 AV5 10 27 9
AV5 17 40 86 AV4 12 27 43 AV5 9
40 87 AV4 17 27 51 AV2 10 40 87 AV5 21 28 40 AV5 40 88 AV3 15 28 65 AV5 10 40 88 AV4 22
~9 28 82 AV5 12 40 88 AV5 17 30 9
AV2 8
40 88 AV6 15 30 9
AV5 34 40 90 AV3 10 30 20 AV2 9
40 90 AV4 16 30 40 AV5 15 40 90 AV5 10 30 40 AV6 10 40 92 AV3 12 30 113 AV5 10 40 92 AV5 15 30 114 AV5 26 40 93 AV2 12 32 106 AV3 12 40 93 I
AV5 12 32 110 AV3 12 40 95 AV2 12 32 111 AV1 9
40 95 AV3 12 32 111 AV3 13 40 95 AV4 25 32 111 AV4 9
40 95 AV5 12 33 12 AV2 11 40 100 AV2 14 33 12 AV3 10 40 100 AV3 10 33 12 AV4 10 40 100 AV4 13 33 12 AV6 100 AV5 12 33 34 40 100 AV6 13 33 34 40 105 AV2 8
33 34 10 40 105 AV4 17 33 91 7
40 105 AV5 18 33 108 AV3 13 40 106 AV3 14 33 110 AV3 22 40 106 AV4 20 33 110 AV5 11 40 106 AV5 23 33 110 AV6 8
41 23 AV2 7
33 111 AV3 17 41 97 AV5 13 33 111 AV4 19 41 105 AV3 9
33 111 AV6 18 42 20 AV6 11 34 15 AV5 10 42 100 AV2 20 36 13 AV1 10 42 100 AV3 16 36 13 AV2 9
42 100 AV4 20 36 14 AV1 10 42 100 AV6 12 36 39 AV3 19 42 101 AV3 16 36 79 AV4 16 42 101 AV4 21 36 104 AV2 15 42 101 AV5 23 36 104 AV3 I
9 42 104 AV3 17 36 104 104 AV4 14 AV5~2 36 105 AV2 3
46 AV6 19 36 105 AV5 3
66 AV2 13 36 106 AV5 8
43 66 AV3 12 36 106 AV6 11 43 92 AV3 15 36 107 AV3 10 43 93 AV4 11 I AV# - Location of AVB intersection with the tube (there are up to 6)
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Enclosure Vogtle Electric Generating Plant - Unit 1 1 R16 Steam Generator Tube Inspection Report Table 3 VOg1tle 1R16 SG4AVBWear Ind"Icatlons (continued)
Row Col Location 1R16 Row Col Location' 1R16
%TW
%TW 36 109 AV3 11 43 101 AV4 18 37 80 AV4 10 43 101 AV5 29 38 19 AV5 10 44 91 AV5 13 38 35 AV2 10 44 96 AV2 10 38 52 AV3 7
44 96 AV3 30 38 52 AV4 10 44 96 AV4 27 38 55 AV4 10 44 96 AV6 16 38 74 AV2 8
44 97 AV2 20 38 76 AV3 12 44 97 AV4 22 38 76 AV4 13 44 97 AV5 26 38 76 AV6 9
44 99 AV6 9
38 86 AV4 16 45 22 AV5 9
38 96 AV2 14 45 101 AV1 10 38 96 AV4 10 45 101 AV5 10 38 96 AV5 11 45 101 AV5 7
38 103 AV4 11 48 97 AV6 10 38 104 AV3 10 49 54 AV2 17 38 104 AV4 14 49 54 AV3 32 38 104 AV5 13 49 54 AV4 29 38 108 AV4 14 49 54 AV5 22 39 51 AV4 10 49 95 AV3 10 39 51 AV5 10 50 63 AV2 16 39 51 AV6 12 50 63 AV3 22 39 56 AV2 11 50 63 AV4 18 39 56 AV3 17 50 76 AV3 13 39 56 AV4 14 50 76 AV4 13 39 58 AV2 11 50 76 AV5 27 39 58 AV4 18 53 89 AV4 15 39 58 AV6 11 53 90 AV1 10 39 75 AV5 15 53 90 AV5 12 39 107 AV3 10 53 90 AV6 12 40 24 AV5 15 54 36 AV5 13 40 25 AV3 10 54 38 AV1 10 40 29 AV2 11 54 38 AV5 11 40 39 AV3 13 54 38 AV6 10 40 56 AV3 15 55 40 AV6 12 40 62 AV2 26 55 82 AV5 12 40 62 AV3 33 56 41 AV5 11 40 62 AV4 26 56 81 AV6 11 40 62 AV5 13 57 55 AV6 10 40 78 AV2 18 58 48 AV5 10 40 78 AV3 17 58 65 AV1 11 40 82 AV2 13 58 73 AV6 13 40 82 AV3 23 59 57 AV5 14 40 82 AV4 33 59 59 AV2 13 40 82 AV5 18 40 84 AV2 14 AV# - Location of AVB mtersectlon with the tube (there are up to 6)
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Enclosure Vogtle Electric Generating Plant - Unit 1 1R16 Steam Generator Tube Inspection Report ODSCC A single axial ODSCC indication was found in SG4 R8 C57. It is located below the bottom of the expansion transition at TSH-O.19. It is entirely within the tubesheet. Criteria for in situ proof testing and leak testing were not met; therefore, in-situ testing was not required to be performed to demonstrate tube integrity. The tube was plugged based on detection of axial ODSCC.
Axial Length inches) 0.13 Slippage Monitoring Bobbin data from SG1 and SG4 was screened for tubesheet indications of greater than 50 volts with a phase angle between 25 and 50 degrees, indicative of a severed tube. No tube severance indications were found. There was no leakage present during Cycle 16. Therefore, the performance criteria for Cycle 16 with respect to the H* Temporary Alternate Repair Criteria (TARC) have been satisfied.
Number of Tubes Plugged Table 5 presents a summary list of all SG tubes plugged in 1 R16 and the related degradation mechanism.
Table 5: 1R16 Plugged Tubes (2)
~
Row Col Ind Degradation Mechanism 1
26 110 PCT Foreign Object Wear 4
8 57 SAl ODSCC Total plugging in the SGs after 1R16 is as follows:
SG 1 - 28 tubes for a total of 0.50% tubes plugged SG 2 - 19 tubes for a total of 0.34% tubes plugged SG 3 - 33 tubes for a total of 0.59% tubes plugged SG 4 - 68 tubes for a total of 1.21 % tubes plugged Condition Monitoring Conclusions No indications, including +Point testing of I-code indications and 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, were found to exceed the condition monitoring limits specified in the Degradation Assessment. No tubes required in-situ pressure testing to demonstrate tube integrity.
None of the AVB wear indications in either SG1 or SG4 exceed the Condition Monitoring limits as given in the 1 R16 Degradation Assessment.
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Enclosure Vogtle Electric Generating Plant - Unit 1 1R16 Steam Generator Tube Inspection Report As stated above, one tube in SG1 was identified by eddy current testing to have an indication associated with foreign object wear. No additional secondary side tube damage attributable to loose parts/foreign objects was identified from the foreign object search and retrieval (FOSAR) and visual inspections.
Given the absence of operating leakage during Cycle 16, it is concluded that there was no leakage from plugs. This is consistent with the video inspection of the tube plugs in all 4 SGs which produced no exceptions to expected conditions.
Evaluation of the indications found in the 'I R 16 inspections confirms that the tube integrity structural and leakage performance criteria condition monitoring requirements specified in Reg.
Guide 1.121 and NEI-97 -06 Revision 2 are satisfied.
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