ML19242A835

LER 79-013/03L-0 on 790710:during Testing of RHR Subsys Logic a Relay 10A-K46A Failed to Energize.Caused by Disconnected Lead of Contact to Relay Coils Control Circuit. Wire Was Reconnected & Sys Returned to Operation

ML19242A835
Person / Time
Site:	Vermont Yankee
Issue date:	08/03/1979
From:	Conway W VERMONT YANKEE NUCLEAR POWER CORP.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19242A830	List: ML19242A829 ML19242A835
References
LER-79-013-03L, LER-79-13-3L, NUDOCS 7908060444
Download: ML19242A835 (2)

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VTVYS1 03000271 LER 79-11/3L EVENT DESCRIPTION AND PROPdBLE CONSEQUENCES During surveillance testing of the "A" RHR Subsystem Logic, Relay 10A .i46A failed to energize. The failure of this relay to energize would have prevented valve V10-27A from automatically opening upon receipt of an automatic initiating signal from its normal control logic. This con-dition is contrary to the requirements of Tech. Spec. Table 3.2.1. Al-ternate testing eas immediatel, initiated in accordance with the require -

ments of Tech. Spec. Section 6.5.A.4.

During this event, the redundant auto opening logic was tested and proved operable, providing for the auto-opening of the valve if conditions required that action. Both Core Spray Subsystems, the remaiaing LPCI, the Containment Cooling Subsystem and b?tb Diesel Generators were operable.

Fased upon the preceding equipment availability, it is concluded that there were no adverse consequences to the public health or safety as a result of this event. There were no previous reportable occurrences of this type.

CAUSE DESCRIPTION AND CORRECTIVE ACTIONS During an investigation of the inoperability of Relay 10A-K46A, 't was found that a lead came off a contact of the relay coils control cir-cuit. Immediate corrective action consisted of reconcocting the aire which employs a disconnect type lug. Additienally, all similar type con-nections in the control panel were checked to assure no similar conditions oxisted. Since this event is the first of its kind, no additional correc-tive action is envisioned.

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