05000338/LER-1980-012-03, /03L-0:on 800111,during Testing in Mode 3 to Verify Main Steam Trip Valve Closure Time,Trip Valve Failed to Close Fully within Required Five Seconds.Cause Unknown. Valve Was Retested.Closure Time within Acceptable Limits

/03L-0:on 800111,during Testing in Mode 3 to Verify Main Steam Trip Valve Closure Time,Trip Valve Failed to Close Fully within Required Five Seconds.Cause Unknown. Valve Was Retested.Closure Time within Acceptable Limits

ML19260D986
Person / Time
Site:	North Anna
Issue date:	02/08/1980
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19260D983	List: 05000338/LER-1980-012, Forwards LER 80-012/03L-0 05000338/LER-1980-012-03, /03L-0:on 800111,during Testing in Mode 3 to Verify Main Steam Trip Valve Closure Time,Trip Valve Failed to Close Fully within Required Five Seconds.Cause Unknown. Valve Was Retested.Closure Time within Acceptable Limits
References
LER-80-012-03L, LER-80-12-3L, NUDOCS 8002120707
Download: ML19260D986 (1)

LER-1980-012, /03L-0:on 800111,during Testing in Mode 3 to Verify Main Steam Trip Valve Closure Time,Trip Valve Failed to Close Fully within Required Five Seconds.Cause Unknown. Valve Was Retested.Closure Time within Acceptable Limits

Event date:
Report date:
3381980012R03 - NRC Website

text

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l During periodic testing in Mode 3 to verify main steam trip valve closure time TV-l l MS101A failed to fully close from the Train B control room pushbutton within the requiged u

a 5 second criterion.

Because the closure time of the trip valve was acceptable using l

o,4 the Train A pushbutton, the health and safety of the general public were not af fected. l g,s Reportable pursuant t o T. S. 6. 9.1. 9. b.

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40 41 42 43 44 47 CAUSE CESCRIPTION AND CORRECTIVE ACTIONS h The cause of this discrepancy is not known.

An airline check valve was disassembled j

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The check valve was then reassembled;

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Attachment:

Page 1 of I Doc ke t No. 50-313 Re po r t No. LER 30-12/03L-0 Descrittien of Event On January 11, 19 30, during periodic testing, nain steam trip valve TV-MS101A failed to close within the required isolation tice of 5 seconds from the Train B control room pushbutton.

Closure tice was measured at

5. 2 seconds.

Probable Consequences of Occurrence The consequences cF-this event evere.-limited because the closure -ice for TV-MS101A was acceptable using the pushbutton for Train A.

Also, because the Action statement of T.S.

3. 7.1.5 was strictly adhered to, the health and safety of the general public were not af fected.

There are no generic implications associated with this occurrence.

Cause of Event

It is not known why it took TV-MS101A more than 5 seconds to fully close using the Train 3 pushbutton.

Since a stop watch is presently used to neasure the valve closure time, human error in the use of the stop watch could have af fected the final test results.

Inmediate Corrective Action An airline check valve was disassembled and inspected for debris which night have accumulated and caused the valve disc to bind.

During the inspection no problem was found and the valve was reassembled.

TV-MS101A was then retested using the Train B pushbutton and the closure time was within acceptable limits (4.8 seconds).

Scheduled Corrective Action No further actions are required.

Actions Taken to Prevent Recurrence No further actions are required.

1951 335