ML20008E881

Forwards LER 81-010/03L-0

ML20008E881
Person / Time
Site:	McGuire
Issue date:	03/04/1981
From:	Parker W DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20008E882	List: ML20008E881 ML20008E885
References
NUDOCS 8103100441
Download: ML20008E881 (3)

Text

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Dintn POWEH COhmm POWEM UUtLDINtl 422 Sot Tu Citt acit Sinter, Citant.orte, N C 2aau w w. - o a = c a. s a. March 4, 1981

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Mr. James P. O'Reilly, Director U. S. Nuclear Regulatory Commission _

Region II

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101 Marietta Street, Suite 3100 .'

Atlanta, Georgia. 30303 Ng%.'j' y ,4[ ((,/p '&)

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Re: McGuire Nuclear Station Unit 1 y U8 /= .

Docket No. 50-369 .. br/,hg/

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Dear Mr. O'Reilly:

Please find attached Reportable Occurrence Report R0-369/81-10. This report concerns low RHR flow due to a broken air supply line. This inci-dent was considered to be of no significance with respect to the health and afety of the public.

T V ry truly yours, I

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' William O. Parker, J,r.\

\J RWO:ses Attachment ec- irector Mr. Bill Lavallee

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office of Management and Program knalysis Nuclear Safety Analysis Cetiter U. S. Nuclear Regulatory Commission P. O. Box 10412 Washington,.D. C. 20555 Palo Alto, California 94303 81031 00441 'S8 f

MCGUIRE NUCLEAR STATION INCIDENT REPORT Report Number: R0-369/81-10 Report Date: February 25, 1981 Occurrence Date: February 7, 1981 Identification of Occurrence: On February 7, 1981 at 1604 Hours, Residual Heat Removal (ND) Flow was Found to be About 1500 GPM.

Condition Prior to Occurrence: Mode 6 Initial Fuel Loading Description of Occurrence:

During routine surveillance on February 7, 1981, the control operator discovered total ND flow return at about 1500 GPM rather than the 3000 GPM required by -

Technical Specification 4.9.8.1. He then re-adjusted the flow to 3000 GPM.

Apparent Cause of Occurrence:

About 0300 hours0.00347 days <br />0.0833 hours <br />4.960317e-4 weeks <br />1.1415e-4 months <br />, on February 7, 1981, the ND system was in operation with ND Pump 1-3 running and supplying watcr to both trains through the cross-connect piping. Flow was divided about equally between trains and was controlled by valves 1-ND 14(ND Pump 1-B Discharga Flow Control) and 1-ND 29 (ND Pump 1-A Discharge Flow Control). An air line supplying the actuator on 1-ND-29 broke and allowed the valve to fail open. The operators on duty immediately isolated train A to limit ND Pump B flow and to protect the pump. 1-ND 14 was not re-

.ijusted to compensate for the loss of the train A flowpath until 1604 hours0.0186 days <br />0.446 hours <br />0.00265 weeks <br />6.10322e-4 months <br /> on sebruary 7, 1931.

Analysis of Occurrence:

At the time of the occurrence, only new fuel was installed in the reactor so overheating, due to decay heat, was not a problem. No chemical changes were being made so mixing was also unnecessary. Since the normal functions of the ND system were not needed, the safe operation of the plant and the health and safety of the public were not affected by the reduced ND flow. In subsequent fuel loading operations, either chemical mixing or residual heat removal and fuel temperatures could be af fected by low ND flow. The operating procedure for the residual heat removal system did not specifically state that 3000 GPM or greater is required during refueling, but the operators on duty were aware of the requirement. The operator 7 apparently were so involved with responding to the immediate problem of excessive flow through ND Pump 1-B and subsequent actions  ;

to investigate and correct the failed control valve (1-ND-29), that they neglected c to recheck and adjust the ND flow back-up to 3000 GPM.

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Corrective Actior.-

The low UD flow was re-adjusted to 3000 GPM immediately on discovery. 1-ND-29 was repaired and an investigation into the vibration related air line failure was conducted. The investigation resulted in a Nuclear Station Modification to '.eplace rigid air supply lines with flexible lines. The NSM and work request were written to replace instrament air lines on several valves with vibration problems similar to 1-ND-29.

This incident was reviewed by Operations. Supervisors agreed that shift person-nel would be advised to review operating parameters as soon as possible after an event (after the immediate corrective action is complete). More frequent surveil-lance of a system which has experienced mechanical problems should lessen the possibility of a recurrence of this type of incident. The Operating procedure for the ND system will be modified to include a note specifying the required flow for Mode 6 (refueling) operation.

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