ML20084B026

AO 3-2-7:on 730601,one of Two Motor Actuators for MOV 851A Improperly Moved to Closed Position Following Initiation of Automatic Safety Injection as Result of Spurious Signal from High Steam Line Flow Logic.Caused by Logic Malfunction

ML20084B026
Person / Time
Site:	Indian Point
Issue date:	06/11/1973
From:	Caldwell W CONSOLIDATED EDISON CO. OF NEW YORK, INC.
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084B029	List: ML20084B026 ML20084B039
References
AO-3-2-7, NUDOCS 8304060078
Download: ML20084B026 (2)

Text

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'_ .l Consohdated Edison Company of New York. Inc.

4 Irving Place. New York. N Y 10003 Tetephone (212) 400-5181 June 11, 1973 Re: Indian Point Unit No. 2 AEC Docket No.

Facility Operating 50-247 y, g Hps N License DPR-26 *,7 ,

Mr. John F. O' Leary, Director Sl b }/r' Directorate of Licensing m rt U. S. Atomic Energy Commission ef 6/g',Il g ' v/j Washington, D. C. 20545 j-fr y,. 78/y0-f . ' ?,

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Dear Mr. O' Leary:

The following report of Abnormal Occurrence No.

Mr

_ es.\i 3-2-7 is pro- T vided pursuant to the requirements of Section 6.6.1.B of the Technical DPR-26.

Specifications to Facility Operating License No.

On June 1, 1973, at 0202 hours0.00234 days <br />0.0561 hours <br />3.339947e-4 weeks <br />7.6861e-5 months <br />, automatic safety injection was initiated as a result of a spurious signal from the high steam line flow logic. By design, this signal caused a trip of the reactor whica at the time was operating at essentially acro power for physics testing. The three high head safety injection pumps started as expected; however, one of two motor actuators (for MOV 851A), which controls the flow path from pump No. 22 to supply either of the injection headers, improperly moved to a closed position.

Mr.

the U. A. Fasano of the Region I Regulatory Operat.'ons Office of on June S. 1,Atomic Energy Commission was notified by telephone 1973 of the occurrence. In addition, a telegram ,

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was sent on the same date to confirm the notification.to the Director of the Region I Of Investigation into the cause of the improper operation of MOV 851A revealed that the fault was due to a logic malfunction. Normally, MOV failed851A to start.would only be required to close if high head pump No. 23 The logic circuitry that furnishes this pro-tection includes a timer component which served to delay actu-ation of theof the particular safety injection MOV signal.until six seconds after the initiation allow sufficient time for pump No.This timing, however, did not Instead, the logic controlling the actuation 23 to start in this of MOV 851Ainstance.

sensed i

that the pump had not yet started and supplied a closing signal.

To prevent this situation from recurring, the timers in the operating logics for MOV 051A and B were reset for 15 seconds.

It is noteworthy, that on June 6, 1973, following another simi-

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8304060078 730611 # O gDRADOCK 05000247 PDR (*QV 3S30

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o Mr. John F. O' Leary June 11, 1573 Re: Indian Point Unit No. 2 AEC Docket No. 50-247 Facility Operating License DPR-26 larly spurious safety injection signal, these logic circuits operated properly (i.e., all three high head pumps started and MOV 851A and B remained in their proper, open position).

There are no significant safety implications related to this occurrence because all three high head pumps did, in fact, start and render both headers capable of supplying safety injection flow. Furthermore though MOV 851A and.B do, under certain circumstances, operate automatically in the closed direction, they can at any time be reopened manually, should it be necessary. In light of these reasons, therefore, it is considered that the safety of the facility was not compro-mised.

Our Nuclear Facilities Safety Committee has reviewed the circum-stances of this occurrence and concurs that it does not represent a significant hazards consideration.

Very truly yours

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