05000369/LER-1981-061, Forwards LER 81-061/03L-0.Detailed Event Analysis Encl

Forwards LER 81-061/03L-0.Detailed Event Analysis Encl

ML20009G190
Person / Time
Site:	McGuire
Issue date:	05/19/1981
From:	Parker W DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20009G191	List: 05000369/LER-1981-061, Forwards LER 81-061/03L-0.Detailed Event Analysis Encl 05000369/LER-1981-061-03, /03L-0:on 810420,primary Containment Integrity Lost.Outer Door of Lower Personnel Air Lock Open & Inner Door Closed But Not Sealed.Outer Door Open Due to Faulty Limit Switch & Inner Door Due to Too Quick Closing
References
NUDOCS 8108030408
Download: ML20009G190 (2)

LER-1981-061, Forwards LER 81-061/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
3691981061R00 - NRC Website

text

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OFFIC!AL COPY DUKE Powen COMPANY yP,'JRC j;gg; Powen Dust.ngwo 4c2 Soutit Citt:acu SrazzT, Caunt.orTz, N. C. 28242 b

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May 19, 1981 272-4c e s J

Mr. James P. O'Reilly, Director y\\p[" ~ ~g/

U.S. Nuclear Regulatory Commission Region II

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.s 101 Mariecta Street, Suite 3100 V '. s.

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Re: McGuire Nuclear Station Unit 1

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Docket No. 50-369 y,,, m,,, umron y ceu. mss o<

Dear Mr. O'Reilly:

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7>369/81'g This report

- r Please tind attached Reportabla Occurrence Report 4

concerns the lower personnel air lock not sealing proper y.

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

Very truly yours, William O. Parker, Jr.

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

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

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8108030408 810519 PDR ADOCK 05000369 S

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McGUIRE NUCLEAR STATION INCIDENT REPORT Report Number:

81-61 Report Date: May 8, 1981 Occurrence Date: April 20, 1981 Facility: McGuire Unit 1, Cornelius, N. C.

Identification of Occurrence: The lower personnel air lock was not sealed closed.

Condition Prior to Occurrence: Mode 3, Hot Standby Description of Occurrence: Primary containment integrity was lost.

The outer door of the lower personnel air lock was open, and the inner door was closed but no-sealed.

This represented a degraded mode of operation, and was re-portable pursuant to Technical Specification 3.6.1.1.

"pparent Cause of Occurrence:

The outer door of the lower personnel ait lock was found wide open, and the hydraulic motor for the door was running.

This apparently resulted from a faulty limit switch.

The inner door had apparently closed too quickly causing it to bounce back open.

While it was open but after tripping the limit switch, the locking pins extended and the seals inflated.

Analysis of Occurrence:

On April 20, 1981 at 0745 hours0.00862 days <br />0.207 hours <br />0.00123 weeks <br />2.834725e-4 months <br />, it was discovered that the lower personnel air lock waa not sealed.

The outer door was wide open with the hydraulic motor still running.

The inner door was partly closed.

The locking pins were extended but not in their receiving holes. The seals were inflated; however, only one seal was actually sealing agairst the door frame.

The Control Room was notified of the situation and the doors were declared in-operable.

The inner door was cycled several times, and it operated properly.

At 0845 hours0.00978 days <br />0.235 hours <br />0.0014 weeks <br />3.215225e-4 months <br /> the doors were returned to an operable status. Since the outer door was open, and there was no assurance that the inner door was actually sealing, it has to be assumed chat containment integrity was lost.

Corrective Action

The doors were cycled several times and they operated pro-perly. Discussions with the manufacturer are being conducted to investigate redesigning the door's hydraulic system.

Safety Analysis

Since there was only new fuel in the core, no radiation existed in the containment.

Therefore, the open personnel air lock did not endanger the health er safety of the public.

If this incident h5d occurred while the plant was operating, immediate shutdown would have been required.