ML20086D775

AO 73-09:on 730410,microswitch Installed in DPIS-129B Failed to Actuate at Required Setpoint.Defective Switch Replaced, Actuating Arm Realigned & Trip Point Actuation Rechecked Repeatedly

ML20086D775
Person / Time
Site:	Vermont Yankee
Issue date:	04/10/1973
From:	Riley B VERMONT YANKEE NUCLEAR POWER CORP.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20086D773	List: ML20086D769 ML20086D775
References
AO-73-09, AO-73-9, NUDOCS 8312050102
Download: ML20086D775 (2)

Text

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VERhiONT YANKEm NUCLEAR POWER CORPORATION SEVENTY SCVCN OMOVC STRrCT RUTLAND, VERMONT 05701 VYV-2603 ",(('$x,,7 i

VERNON VERMONT 05334 April 10, 1973 United States Atomic Energy Commission Directorate of Regulatory Operations, Region I 970 Broad Street Newark, New Jersey 07102 REFERE!!CE: Operating License DPR-28 Docket No. 50-271 i Abnormal Occurrence No. AO-73-09 l Contlenent An defined by Technical Specifications for the Vemont Yankee Nuclear Power Station, Section 6.7.A.c we are reporting the followinR Abnormal Occurrence as AO-73-09 and confirming our telephone conversation with your office.

At approximately 1115 on April 10, 1973, while perfoming. routine quarterly surveillance on the LPC1 break detection logic (i.e. ASB d/p across riocro), a nicroswitch installed in DPIS-129B failed to actuate at the required setpoint of 1-(+.5) psid as specified in Table 3.2.1 of Technical Specifications. The microswitch actuating am was nechanically bound and failed to drop into the cam valley at its required setpoint.

Functionally, this owitch, 2-129B operates in conjunction with switch 2-129D and combined they actuate a relay in their respective string to clase Loop B LPCI valves and actuate Lnop A recirculation valves. The reactor was operating at approximately 757. power at the time of this incident, j In compliance with Note 2 of Table 3.2.1 of the Technicat Specifications the channel was promptly made operable by replacing the defective switch with a bench tested new one, realigning the actuating om, and rechecking trip point actuation repeatedly. Operation was patisfactory after repeated actuations and the channel was declared operable by 1430 on April 10, 1973.

Very truly yours, VERHONT YANKEE NUCLEAR POWER 00RPORATION 8312050103 730413 gDRADOCK0S000 Bradford U Riley ,

N Plant Superintendent B101/rph

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, ,,, . u r ... . n . . u .. .. e,i- t ,e m t o v4 4.. .aa a.o im nau m sus Licensee: Vemont Yankee Nuclear Power Corp.

J. G. Kcppler, R0 (2) east Docket No.: 50-271  ;

Abnormal Occurrence: A0-73-09 t o o. . . . . . ...y imnau umaan t, -RO:HQ (5) .

DR Centr: 1 Files (1) nas The attached report from the subject licensee is Regulatoi,r Standards ;3)

Dir. of licensin:: (131 foruarded in accordance uith no Manual chanter 1000.

T o ca..n. . . . ,iu im nau a no The action taken by the licensee is considered )

J DATE appropriate. Followup will be perfomed during i the next insocction as oporonrinte. Conim of r nor.i o . n. .no a.o atuaan the report have been forvarded to the PDR, Local p/, q , @p #

PDR, NSIC, DTIE and State representatives. The D. L. Caphton, RO:1 licensee vill 'subrait a 10 day written report to Tmu ouh/11/7.3 Licensing use ovena wt ron aooivic t atunnu e,, , ,,y o m.,j g

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