ML19256C917
| ML19256C917 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 07/12/1979 |
| From: | Bryan S, Klinger G, Nolan F NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | |
| References | |
| PNO-79-234, NUDOCS 7910150744 | |
| Download: ML19256C917 (1) | |
Text
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PRELIMINARY NOTIFICATION July 12,1979 PRELIMINARYNOTIFICATIONOFEVENTORUNUSUALdCCURRENCE--PNO-79-234
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This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest sionificance.
The information oresented is as initially received without verification or evaluation and is basically all that is known by IE staff on this date.
Facility:
Vermont Yankee Nuclear Power Corporation Vermont Yankee (DN 50-271)
Subject:
ERRATIC BEHAVIOR OF RECIRCULATION PUMP At about 3:15 p.m. on July 11, 1979, the licensee noted erratic speed on Recirculation Pump "A".
The speed variations were causing changes in core flow with resultant changes in the reactor power level of less than 1/2 percent.
The reactor was operating at 98 percent power.
Troubleshooting revealed the problem to be variations in the Motor-Generator (M-G) Set generator output voltage caused by the M-G Set tachometer.
Plant power was reduced to 50% at 12:16 a.m. on July 12.
The "A" Recirculation Pump was secured and the defec-tive tachometer replaced.
Pump restart was at 2:05 a.m. on July 12.
Return to full power began at 3:15 a.m.
The plant was back to 95 percent power by 8:00 a.m.
This PN is issued for information only.
Further action by NRC Region I will involve followup during routine inspection.
Media interest is expected because of sensitivity to nuclear plant issues.
The State of Vermont has been informed.
The licensee plans to mention this occurrence in the daily recorded telephone status report to the news media.
A press release is not planned by the NRC.
NRC, Region I, (Philadelphia) received notification of this occurrence by telephone from assistant plant superintendent at 5:15 p.m. on July 11, 1979.
7, :.
Contact:
GKlingler, IE x28019 FNolan, IE x28019 SEBryan, IE x28019 Distribution:
Transmitted H St Cnaltmar Hendrie Commissioner Bradford S. J. Chilk, SECY Commissioner Kennedy Commissioner Ahearne C. C. Kammerer, CA Commissioner Gilinsky nACRS (For Distribution)
Transmitted:
MNBB P. Bldg 12:c 7 V. Stello, IE L. V. Gossick, ED0 H. R. Denton, NRR Region L H. L.'Ornstein, EDO R. C. DeYoung, NRR J. J. Fouchard, PA R. J. Mattson, NRR N. M. Haller, MPA D. Vassallo, NRR (MAIL)
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