ML20086D769
| ML20086D769 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 04/13/1973 |
| From: | Riley B VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20086D773 | List: |
| References | |
| AO-73-09, AO-73-9, VYV-2607, NUDOCS 8312050099 | |
| Download: ML20086D769 (2) | |
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sevcNTY OcVEN OHOVC STRcCT IlUTI.ANo, VimFIONT 03701 VYV-2607 P.O.DOX 157 VERNON, VERMONT o5354 April 13, 1973 N'
Director t-I Directorate of Licensing O
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United States Atomic Energy Commission i
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REFERENCE:
Operating License DPR-28 d
i Docket No. 50-271 g ir Abnormal Occurrence No. A0-73-09 F
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Centlemen:
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w, As defined by Technical Specifications for the Vermont Yankee n..cio.c unwar gration, socrinn h.i.n.<i, we are vennrring rno rniinwing Abnormal Occurrence as A0-73-09.
g At approximately 1115 on April 10, 1973, while performing routine rV quarterly surveillance on the LPCI break detection logic (i.e., A>B d/p acrossrisers),amicroswitclLJ)nstalledinDPIS-129Bfailedtoactuateatfdh
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TechnicalSpecifications(.'ThemicrisiIwitchac!uatingarmwasmechanically the required setpoint of 1 (+.5 psid as spect. g t nhin 1.2.1 of J~
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-f bound and failed to drop into the cam valle) at its required setpoint.
s yf,1[2 Functionally, this switch, 2-129B, operates in conjunction with switch 2-129D and combined they actuate a relay in their respective string to 7-close loop B LPCI valves and actuate Loop A recirculation valves.
The reactor was operating at approximately 75% power at the time of this incident.
In compliance with Note 2 of Tabic 3.2.1 of the Technical Specifications the channel was promptly made operabic by replacing the defective switch with a bench tested new one, realigning the actuating arm, and rechecking trip point actuation repeatedly. Operation was satisfactory after repeated actuations and the channel was d clared operabic by 1430 on April 10, 1973.
l 8312050099 730413
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d VERMONT Y'/ /t(EE NUCLEAR PGWER CORPORATION
_l Directorate of Licensing April 13, 1973 Page 2 The Plant Operations Review Committee reviewed the reported incident and concluded that the newly installed switch, and other similar ones, be closely observed for any indication of bound actuating arms at subsequent 30 day functional surveillance tests.
Very truly yours, VERMONT YANKEE NUCLEAR POWER CORPORATION PM O.
B.W. Riley
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Plant Superintendent BMB/kbd 6
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