05000369/LER-1981-070, Forwards LER 81-070/03L-0.Detailed Event Analysis Encl

Forwards LER 81-070/03L-0.Detailed Event Analysis Encl

ML20009F720
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
ML20009F721	List: 05000369/LER-1981-070, Forwards LER 81-070/03L-0.Detailed Event Analysis Encl 05000369/LER-1981-070-03, /03L-0:on 810426,while in Mode 3,initial Fuel Loading Cold Leg Injection Accumulator C High Level Alarm Received in Control Room.Caused by Leaking Discharge Check Valves.Leaking Valve Repaired
References
NUDOCS 8107310454
Download: ML20009F720 (2)

LER-1981-070, Forwards LER 81-070/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
3691981070R00 - NRC Website

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OFFICIAL COPY DUKE POWER COSIPm Powen Dru.ntNo 422 Socin Curuen STHEET CnAR1.OTTE, N. C. 28242

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tj O W I L LI AM Q PAR K E R, J R, SC' ##CSIDENT Tgtgpuomg: Anta 704 s.t a.coveno~

May 26, 1981 373.ac e 3 y?0

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Mr. James P. O'Reilly, Director f'

f Er. g 37}f U.S. Nuclear Regulatory Commission

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Region II gk g'

101 Marietta Street, Suite 3100 l

Atlanta, Georgia 30303 JUL " 019M

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W-cowsscH g'f(

s Re: McGuire Nuclear Station Unit 1 N

Docket No. 50-369 N

Dear Mr. O'Reilly:

Please find attached Reportable Occurrence Report R0-369/81-70.

This report concerns cold leg accumulator 'C' being declared inoperable.

This incident was considered to be of no significance with respect to tha health and safety of the public.

V truly yours, c

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. LL I h - La o[ a

' William O. Parker, Jr.

V RWO:pw Attachment cc: Director Mr. Bill Lavallee Office of Management & Program Analysis Nuclear Safety Analysis Center U.S. Nuclear Regulatory Commission Post Office Box 10412 Washington, D. C.

20555 Palo Alto, CA 94303 Ms. M. J. Graham Resident Inspector - NRC McGuire Nuclear Station jh Si

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8107310454 810526 PDR ADOCK 05000369 S

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McGUIRE NUCLEAR STATION INCIDENT REPORT Report Number:

81-70 Report Date: May 26, 1981 Occurrence Date:

April 26, 1981 Facility: McGuire Unit 1, Cornelius, N. C.

Identification of Occurrence: Cold leg injection accumulator C declared in-operable due to high level.

Conditions Prior to Occurrence: Mode 3, Hot Standby Description of Oce_7rrence: At 1230 hours0.0142 days <br />0.342 hours <br />0.00203 weeks <br />4.68015e-4 months <br /> on April 26, 1981, cold leg injection accumulater C was duclared inoperable.

The accumulator C high level alarm (64.5%) wa; received in the Control Room.

This indicatad that the contained volume of water was above 8496 gallons and thus, reportable pursuant to Technical Specification 3.5.1.1.

Apparent Cause of Occurrence:

The cold leg accumulator C discharge check valves were leaking which allowed reactor coolant (NC) system water to 'ill the accumu-1 lator above its alarm setpoint.

Analvsis of Occurrence: A periodic test, Reactor Coolant Pressure Isolation Valva Leak Rate Test, performed April 25-28 found that cold leg accumulator C discharge check "alves were leaking past their, seats. At the time of the incident, NC system pressure was greater than 1000 psig and cold leg accumulator C pres. cure was approximately 425 psig.

Since the discharge check valves were leaking, the NC system filled the accumulator above its high level alarm setpoint.

Safety Analysis

The cold leg accumulators aaa passive and would only be used during an accident involving a large NC system brec 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 NC system break had occurred, cold leg accumulator C would have functioned as designed because the water level was close to its alarm setpoint.

Furthe rmore, the accident analysis indicates that the contents of only three accumulators need to be in-jected in order to limit the peak fuel clad temperature at or below the maximum allowable during an accident.

Corrective action

No corrective action was taken to reduce level since pres-surizer pressure was reduced below 1000 psig at 1426 hours0.0165 days <br />0.396 hours <br />0.00236 weeks <br />5.42593e-4 months <br /> on April 26, 1981.

Thus, Technical Specification requirement 3.5.1.1 was no longer applicable.

Work Requests were written to repair the leaking valves. After the valves are repaired, they will be retasted.