ML20070G951
| ML20070G951 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 03/06/1991 |
| From: | Scace S NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| MP-91-211, NUDOCS 9103130123 | |
| Download: ML20070G951 (2) | |
Text
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00Ws-500D Docket No. 50-423 RE: 10CFR50.36 March 6, 1991 MP-91-211 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington. D.C. 20555 hlillstone Nuclear Power Station. Unit No 3 Steam Generator Tube Pluccinc
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Gentlemen:
This Special Report is being submitted witi.m it days pursuant to the requirements of Plant i echnical 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 team generator tubes, to document the nurnber of tubes plugged in each steam generator.
The eddy current inspections conducted at the end of Cycle 3 were completed on February 21, 1991. A total of 7i01 tubes or 31.6 percent of the total tubes were inspected. The inspections were performed in Steam Generators 13 and D. Eddy current testinc identified 9 flaws greater than or equal to the plugging limit in 5 tubes. The plugging limit is defined in the Technical Specifications as an imperfection depth of 40 percent nominal tube wall thickness. All 5 tubes exhibited degradation attnbuted to anti-vibration bar wear. These tubes are identified on Table 1 (attached) and were removed from service utilizing Babcock and Wilcox rolled plugs on February 23,1491.
The complete results of the steam generator tube inspection will be submitted within 12 months in accordance with Plant Technical Specification J.4.5.5.b.
The licensee contact for this special report is Larry Loomis who may be reached at (203) 444-5468.
Wry truly yours, NORTHEAST NUCLEAR ENERGY COMPANY l
kU/EYScace n
/ Stephe N(Q$Yg Director, Millstone Station y
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SES:LELimo
Enclosure:
Table 1 O
cc:
T. T. Martin, Region 1 Administrator l
W. J. Raymond. Senior Resident inspector. Millstone Site f
D. H. Jaffe. NRC Project Manager, Millstone Unit Nos.1 and 3 9103130123 910306 l
PDR ADOCK 05000423 1,;*
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l Table 1 hilLLSTONE 31001 EDDY CUltitENT INSPECTION SL'SISIAIE SL_D SG-.D TOTAL Number of Tubes 5626 56:6 11252(22504)2 Number of Tubes Inspected 3555 3546 7101 Tubes with Maximum Flaw
>40 Percent 0
5 5
Tub With hiaximum Flaw
<40. ercent but >20 Percent 9
52 61 Tubes Plupped as a Result of this inspection 0
5 5
LOCATION OF TUDES PLUGGED DURING RIE02 Ron Column S!L 43 42 D
43 103 D
53 86 D
53 SS D
53 90 D
TOTAL TUB.ES PLUGGED TO DATE SOA SEE SL.C SLD TOTAL
' Fabrication 1
2 2
0 5
Preservice 2
1 1
1 5
RF01 1
0 0
1 2
RF02 4
0 4
RF03 0
5 5
TOTAL 8
3 3
7 21 l
l Note: 1 Number in parentheses indicates the total number of tubes in all four steam generators.
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