05000369/LER-1981-073, Forwards LER 81-073/03L-0.Detailed Event Analysis Encl

Forwards LER 81-073/03L-0.Detailed Event Analysis Encl

ML20009G171
Person / Time
Site:	McGuire
Issue date:	05/28/1981
From:	Parker W DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20009G172	List: 05000369/LER-1981-073, Forwards LER 81-073/03L-0.Detailed Event Analysis Encl 05000369/LER-1981-073-03, /03L-0:on 810428,RHR Isolation Valve 1ND1B Failed to Reopen Following Stroke Test.Cause Not Determined.Limit Switches Adjusted & Functioned Properly When Cycled
References
NUDOCS 8108030394
Download: ML20009G171 (2)

LER-1981-073, Forwards LER 81-073/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
3691981073R00 - NRC Website

text

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Dear Mr. O'Reilly:

Please find attached Reportable Occurrence Report R0-369/81-73.

This report concerns the operability of the RHR valve, INDlB. This incident was con-sidered to be of no significance with respect to the health and safety of the public.

Very truly yours, A

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f i William O. Parker, Jr.

RWO:pw Attachment I

l cc: Director Mr. Bill Lavallee l

Office of Management & Program Analysis Nuclear Safety Analysis Center U.S. Nuclear Regulatory Commission P. O. Box 10412 Washington, D. C.

20555 Palo Alto, CA 94303 l

Ms. M. J. Graham Resident Inspector - NRC McGuire Nuclear Ststion l

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8100030094 810528 PDR ADOCK 05000369 s

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s McGUIRE NUCLEAR STATION INCIDENT REPORT

, Report Number:

81-73 Report Date: May 28, 1981 Occurrence Date: April 28, 1981 Facility: McGuire Unit 1, Cornelius, N. C.

t Identification of Occurrence: Valve INDlB would not reopen at the completion of its periodic stroke test.

Condition Prior to Occurrence:

Mode 5 Description of Occurrence: On April 28, 1981 at 1810 hours0.0209 days <br />0.503 hours <br />0.00299 weeks <br />6.88705e-4 months <br />, both trains of the RHR (ND) system were removed from service for periodic tecting of valves INDlB and IND2A. At the completion of the test, IND1B would not reopen.

This placed the plant in a degraded mode of operation as stated in Technical Specification 3.4.1.4.

Apparent Cause of Occurrence:

INDlB would not reopen after its stroke test.

The cause of this incident is unknown.

Analysis of Occurrence:

Both INDlB and IND2A are located in a common line off

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the hot leg of NC loop 3.

The valves are periocically stroked to verify operability. When either valve is closed, both ND trains become inoperable. At I

the end of the periodic test, IND1B would not. reopen. An operator was immediately dispatched to manually open the valve [_and the, system was returned to an operable status at 1830 hours0.0212 days <br />0.508 hours <br />0.00303 weeks <br />6.96315e-4 months <br /> on April 28, 1981

Corrective Action

When the limit switches were adjusted, the valve was cycled and found to be working properly.

Safety Analysis

This incident did not affect the health and safety of the public.

The operators knew that both trains of 'ND would be inoperable during the stroke testing of 1ND1B and IND2A. No operations were underway which would cause a dilution of the reactor coolant boron concentration, and the core outlet tempera-l ture was always >100F sub-cooled. The fact that IND1B would not reopen, only

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slightly extended the time that both ND trains were inoperable.

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