05000369/LER-1981-069, Forwards LER 81-069/03L-0.Detailed Event Analysis Encl

Forwards LER 81-069/03L-0.Detailed Event Analysis Encl

ML20009F613
Person / Time
Site:	McGuire
Issue date:	05/26/1981
From:	Parker W DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20009F615	List: 05000369/LER-1981-069, Forwards LER 81-069/03L-0.Detailed Event Analysis Encl 05000369/LER-1981-069-03, /03L-0:on 810426,while in Mode 3 Initial Fuel Loading,Cold Leg Accumulator D Low Level Alarm Received in Control Room.Caused by Leaking Safety Injection Test Header. Level Restored.Leaking Valve Will Be Replaced & Tested
References
NUDOCS 8107310355
Download: ML20009F613 (2)

LER-1981-069, Forwards LER 81-069/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
3691981069R00 - NRC Website

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May 26, 1981 37 3-*c a s Mr. James P. O'Reilly, Director U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303 Re: McGuire Nuclear Station Unit 1 Docket No. 50-369

Dear Mr. O'Reilly:

Please find attached Reportable Occurrence Report R0-369/81-69.

This report concerns cold leg accumulator 'D' being declared inoperable. This incident was considered to be of no significance with respect to the health and safety of the public.

V t uly yours,

/

U h-G. /~dh. 14q[.

William O. Parker, Jr.

RWO:pw Attachment cc:

Director Mr. Bill Lavallee Office of Management and Program Analysis Nuclear Safety Analysis Center U.S. Nuclear Regulatory Commission P. O. Box 10412 Washington, D. C.

20555 Palo Alto, CA 94303 Ms. M. J. Graham Resident Inspector - NRC McGuire Nuclear Station 8107310355 810526 gDRADOCK 05000369 PDR

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I McGUIRE UUCLEAR STATION INCIDENT REPORT Report Number:

81-69 Report Date:

May 26, 1981

. Occurrence Date:

April 26, 1981 Facility:

McGuire Unit 1, Cornelius, N. C.

Identification of Occurrence: Cold Icg injection accumulator D was declared in-operable due to low water level.

Condition Prior to Occurrence: Mode 3, Hot Standby Description of Occurrence;: At 0630 hours0.00729 days <br />0.175 hours <br />0.00104 weeks <br />2.39715e-4 months <br /> on April 26, 1981, a cold leg accumulator D low level alarm was received in the Control Room.

The level was below the mini-mum required by Technical Specification 3.5.1.1 (8261 gal.) and was thus reportable.

Apparent Cause of_0ccurrence:

The safety injection (NI) test header was app'arently leaking which allowed the accumulator to leak down just below its minimum setpoint.

Analysis of Occurrence: A periodic test, Reactor Coolant Pressure Isolation Valve Leak Rate Test, was performed April 25-28.

This periodic test checked the leakage thru the cold leg accumulators' (A-D) discharge isolation check valves using the NI test header and the NI pumps.

During the performance of the test, the NI pumps were cycled on and off several times and varicus electric valves were cycled oper and closed.

It was during the performance of this test that the leak occurred.

Ona of the discharge isolation check valves on accumulator D was also found to be leaking by its seat and this could have contributed to the leak thrd~the test header.

The level was restored within its normal operating limits at 0645 hours0.00747 days <br />0.179 hours <br />0.00107 weeks <br />2.454225e-4 months <br />, 15 minutes after the low level alarm was received.

Safety Analysis

The four cold leg accumulators are passive and would only be used during a loss-of-coolant accident.

Since there was only new fuel in the core, safe plant operation and the health and safety of the public were not affected.

If the reactor had been at power and a large reactor coolant break had occurred, accumulate.

D would have functioned as designed since its level was just below the minimum re-quired by Technical Specifications.

Also, the level was restored to within its normal limits only 15 minutes af ter the low level alarm was received.

Furthermore, the accident analysis indicates that the contents of only three cold leg accumulators need to be injected in order to limit the peak futi clad temperature at or below the maximum allowable c,uring an accident.

Corrective Action

The accumulator level was restored to within specification at 0645 hours0.00747 days <br />0.179 hours <br />0.00107 weeks <br />2.454225e-4 months <br /> on April 26, 1981.

A work request was written to repair the cold leg accumulator discharge isolation check valve.

The valve will be leak tested after it ic repaired.