ML053070547
| ML053070547 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 10/26/2005 |
| From: | Price J Dominion Nuclear Connecticut |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 05-718 | |
| Download: ML053070547 (5) | |
Text
Dominion Nuclear Connecticut, Inc.
Millstone Power Station
- Dominion Rope Ferry Road Waterford, CT 06385 OGT 2 6 2005 U.S. Nuclear Regulatory Commission Serial No.05-718 Attention: Document Control Desk MPS Lic/RWM RO Washington, DC 20555 Docket No.
50-423 License No.
NPF-49 DOMINION NUCLEAR CONNECTICUT, INC.
MILLSTONE POWER STATION UNIT 3 STEAM GENERATOR TUBE PLUGGING REPORT This special report is being submitted pursuant to the requirements of Plant Technical Specifications 4.4.5.5.a and 6.9.2. Plant Technical Specification 4.4.5.5.a requires that a special report be submitted to the commission within 15 days following completion of each inservice inspection of the steam generator tubes, to document the number of tubes plugged.
The eddy current inspections conducted at the end of cycle 10 were completed on October 12, 2005. The attached tables summarize the number of tubes examined and identify tubes removed from service as a result of the examination. The scheduled inspections were performed in Steam Generators A and C. All operational tubes within the A and C steam generators, a total of 11,207, were inspected with bobbin probes.
Additionally, an augmented sample (6,794 tube locations) was inspected in the A and C steam generators utilizing rotating probes incorporating plus point coils. The plus point probe provides superior detection of both circumferential and axial cracks, and has been qualified per the PWR S/G Examination Guidelines, Appendix H, for the detection of cracking mechanisms. The rotating probe inspections were performed in areas of special interest including hot leg expansion transitions, low row u-bends, tubesheet overexpansions, and dents, as well as locations where the bobbin probe response was ambiguous.
There were no repairs required for the 'C' steam generator.
Two tube repairs were performed in 'A' Steam Generator. Eddy current testing identified flaws greater than or equal to the plugging limit in one (1) tube. The plugging limit is defined within Technical Specifications as an imperfection depth of 40 percent nominal tube wall thickness or greater. Additionally, the second tube was removed from service on a discretionary basis. The basis for the repair is:
One tube was identified with anti-vibration bar (AVB) wear, sized at 42 percent throughwall; exceeding the Technical Specification plugging limit. At the end of cycle 8, AVB wear at this location had been sized at 36 percent through wall.
One tube was identified with anti-vibration bar (AVB) wear, sized at 37 percent throughwall; discretionarily removed from service.
All tubes were removed from service by the installation of Framatome Alloy 690 Rolled Mechanical Tube Plugs on October 12, 2005.
0D
Serial No.05-718 MP3 Steam Generator Tube Plugging Report Page 2of2 The inspection results for both steam generators (i.e., A and C) resulted in a classification as C1.
The complete results of the steam generator tube inspection will be submitted within 12 months in accordance with Technical Specification 4.4.5.5.b.
If you should have any questions regarding this submittal, please contact Mr. David W.
Dodson at (860) 447-1791, extension 2346.
Very truly yours, J.
Prce Sit ce President - Millstone Attachments: 1 Commitments made in this letter: None.
cc:
U.S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406-1415 Mr. G. F. Wunder Project Manager Millstone Unit No. 3 U.S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Mail Stop 8B1A Rockville, MD 20852-2738 Mr. S. M. Schneider NRC Senior Resident Inspector Millstone Power Station
Serial No.05-718 Docket No. 50-423 Millstone Power Station, Unit No. 3 Steam Generator Tube Plugging Report MILLSTONE POWER STATION UNIT 3 DOMINION NUCLEAR CONNECTICUT, INC.
Serial No.05-718 MP3 Steam Generator Tube Plugging Report / Page 2 of 3 TABLE 1 - MILLSTONE 3 RF10 ECT
SUMMARY
SG A SG C Total Number of Tubes (SG A and C only) 5,626 5,626 11,252 Number of Tubes Inspected F/L w/Bobbin Probe 5,227 5,252 10,479 Number of Tubes Inspected w/Bobbin Probe Hot Leg and 365 363 728 Cold Leg Candy Canes Previously Plugged Tubes 34 11 45 Number of Tubes Incomplete w/Bobbin Probe due to 0
0 0
Obstruction Number of Tube Inspections w/MRPC (Total) 3,543 3,251 6,794
- Hot Leg Transitions - Original Scope (tubes) 2,813 2,813 5,626
- Hot Leg Transitions - Scope Expansion (tubes) 0 0
0
'Hot Leg OXP > 28.3V (+3 / -16) (tubes) 179 25 204
- Row 1 and 2 U-Bends - Original Scope (tubes) 122 121 243
'Row 1 and 2 U-Bends - Additional Scope (tubes) 11 1
12 sHot Leg Misc. Special Interest - Diagnostic Exams and 232 163 392 from Previous History (tubes)
- Cold Leg Transitions - Scope Expansion (tubes) 0 0
0
- Cold Leg Misc. Special Interest - Diagnostic Exams and 104 55 159 from Previous History (tubes)
- U-bend. Special Interest - Diagnostic Exams and from 0
1 1
Previous History (tubes)
'PLP / SVI Bounding Special Interest (examinations) 82 72 154 Tubes with Max AVB Wear > 40 %
1 0
1 Tubes with Max AVB Wear >20% but <40%
56 14 70 Tubes with Max AVB Wear <20%
78 11 89 Tubes with Max SVI > 40 %
0 0
0 Tubes with Max SVI >20% but <40%
5 2
7 Tubes with Max SVI <20%
7 14 21 Tubes Plugged as a result of SVI > 37 %
0 0
0 Tubes Plugged as a result of AVB Wear > 37 %
2 0
2 Tubes Plugged as a result of an Obstruction 0
0 0
Tubes Plugged on a discretionary basis 1
0 1
Total Tubes Plugged as a Result of this Inspection 2
0 2
Serial No.05-718 MP3 Steam Generator Tube Plugging Report Attachment I / Page 3 of 3 TABLE 2 - TUBES PLUGGED DURING RF10 FOR AVB WEAR (> 40%)
A S/G (ONLY)
ROW COLUMN
% THROUGHWALL 44 60 42%
TABLES 3 - DISCRETIONARY TUBES PLUGGED FOR AVB WEAR DURING RF10 A S/G (ONLY)
ROW COLUMN i % THROUGHWALL 53 33 37%
TABLE 4 - TOTAL TUBES PLUGGED TO DATE S/G A S/G B S/G C S/G D TOTAL Fabrication 1
2 2
0 5
Preservice 2
1 1
1 5
RFO1 1
0 0
1 2
RFO2 4
0 4
RFO3 0
5 5
RFO4 6
1 0
7 RFO5 1
10 11 MID CYCLE 2
2 RFO6 12 2
14 RFO7 0
51 51 RFO8 8
3 11 RFO9 0
10 10 RF10 2
0 2
TOTAL l
36 4
1 78 129