ML17252A241
| ML17252A241 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 10/21/1976 |
| From: | Stephenson B Commonwealth Edison Co |
| To: | James Keppler NRC/RGN-III |
| References | |
| BBS Ltr. #76-748 | |
| Download: ML17252A241 (3) | |
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. DrescP.ln Nuclear Power Station R.R. #1 Morris, Illinois 60450 Telephone 815/942-2920 e
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BBS Ltr. #76-748 oc*tober 21, 1976 Mr. Jame 1s G ~ Keppler, Regional Di rec tor Di~ectorate of Regulatory Operat{ons - Region III u.. S. Nuclear* Regulatory. Commis*sion 799 Roosevelt Road
- Glen Ellyn, Illinois 60137 Enclosed please find Reportable Occurrence report.number 50-249/1976-18..
This report is being submitted to your office in accordance *with the Dresd.en:
Nuclear Power Station Technical Specifications, Section 6.6.B.
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'B. '-B. Stephenson Station Superintendent Dresden*Nuclear Power Statiort BBS:jo
- Enclosure*
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Director of Inspection & Enforcement Director of Man~gement Information & Program Control Fi.le/NRC Mail Seaton 0ac.k;;1 Gierk
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EVENT DESCRIPTION (Continued) 3-220-58A and -62A yielded leak rates of 20,0 and 5220 SCFR respectively, Since the leakage through valve.3-220-58A was reduced to a value below.Tech Spec limits, no further action was necessary.
Valve -62A was disassembled and repaired, Redundant valves were available and operable during unit operation, This is a repetitive occurrence.
(50-249/1976-18)
CAUSE DESCRIPTION (Co?tinued) these clearances sufficiently to permit a satisfactory disc-to-seat seal, Disassembly of valve 3-220-62A revealed that, in addition to having dirt in the seating area, the valve also had worn disc assembly pins which resulted in an impre-cise disc-to-seat alignment.
The valve was cleaned, and the disc assembly and seal ring were replaced.
Following reassembly, valve -62A was retested, and a leak rate of 1.84 SCFH was obtained.
Because of the high incidence of initial LLRT *failures on the feedwater check valves, the station is currently reevaluating the method of testing these valves.
The significant improvement in LLRT results which are obtained after the valves. have been back-seated with water indicates that the present testing method qoes,not allow an adequate determination of how these valves will perform tinder accident
..,, G.OJl~.i.. tions.
Valves. 3-:220-58A and -62A are 18-inch, tilting disc check valves man-
....,,~4'£a;tttlfecf~by.'.Cr1rie** c~irfp~ny.