ML20057E864
| ML20057E864 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 09/04/1993 |
| From: | Scace S NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| MP-93-710, NUDOCS 9310130271 | |
| Download: ML20057E864 (2) | |
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NORTHEAST UTILITIES
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(2031665-5000 September 4, 1993 DockeI5bdO423 RE: 10CFR50.36 U.S. Nuclear Regulatory Commission Attn: Document Control Desk i
Washington, D.C.
20555 Millstone Nuclear Power Station Unit No. 3 Steam Generator Tube Plugging Gentleman:
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 in each generator.
The eddy current inspections, conducted at the end of cycle 4,'were completed on August 21,1993. A total of 8110 tubes or 35.6 percent of the total tubes in all generators were inspected. The inspections were performed in Steam Generators A and C. Eddy Current testing identified flaws greater than or equal to the plugging limit in 7 tubes. The plugging limit is defined in Technical Specifications as an imperfection depth of 40 percent nominal tube wall thickness. All 7 tubes exhibited degradation attributed to Anti-vibration Bar (AVB) wear. These tubes are identified on Table 2 and were removed from service utilizing Westinghouse Alloy 690 tapered mechanical plugs on August 21. 1994.
Table 1 provides a brief synopsis of the results of the steam generator tube inspection.
The complete results will be submitted within 12 months in accordance with Plant Technical Specification 4.4.5.5.b.
.l The licensee contact for this special report is Larry Loomis who may be reached at (203) 444-546S Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY 080f7 aw
/Steph E. Scace Vice President - Millstone Station SES:LEL:dlr 9310130271 930904 9
Attachment PDR ADOCK 05000423
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cc:
T. T. Martin. Region I Administrator g
P. D. Swetland. Senior Resident inspector, Millstone Unit Nos.1, 2, and 3 d
V. L. Rooney, NRC Project Manager, Millstone Unit 3
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MA / M 273 73p
9/4/93MP-93-710 9
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ATTACIDIENT A 4
Table 1 - MILLSTONE 31993 ECT
SUMMARY
l DESCRIPTION S/G A S/G C TOTAL
- t Number of lubes 5626 5626 22504 l
Number of Tubes inspected 4350 3660 8110
. Tubes with mnimum flaw > 40%
6 1
7 Tubes with Flaws > 209 but < 40%
40 14 54
.j Tubes Plugged as a Result of this Inspection 6
1 7
Table 2 - LOCATION OF TURES PLUGGED DURING RF04 ROW COLUN1N S!G ROW COLUNIN S/G 40 63 A
53 90 A
42 79 A
54 52 A
45 98 A
50 59 A
50 92 C
i i
Table 3 - TOTAL TUBES PLUGGED TO DATE 4
S/G A S/ G 11 S/G C S/G D TOTAL Fabrication 1
2 2
0 5
2 Preservice 2
1 1
1 5
RF01 1
0 0
1 2
RF02 4
0 4
RF03 0
5 5
1 0
7 RF04 6
TOTAL l
14 3
l 4
l 7
l 28
- All four Steam Generators