ML19289D789

LER 79-006/03X-1 on 790111:damaged Wiper Seal Found on Hydraulic Suppressor I-FW-HSS-233 & Suppressor Found Inoperable on Bypass Line.Caused by Improperly Set Poppet Valves.Suppressor Replaced W/Operable Spare

ML19289D789
Person / Time
Site:	North Anna
Issue date:	03/09/1979
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19289D784	List: ML19289D783 ML19289D787 ML19289D789 ML19289D790 ML19289D791 ML19289D792
References
LER-79-006-03X, LER-79-6-3X, NUDOCS 7903140407
Download: ML19289D789 (2)

Text

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LICENSEE EVENT REPORT UPDATE REPORT - Previous Report Date 02-05-79 CONTROL DLOCK: l 1

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[l-j@l 0 l 5 l 0 l 010 l 3 l 368l8 69l@l 0 l1 l1 l1 17 l9 l@lREPORT EVENT DATE 74 75 4 141 DATE 7l 9l@ 80 7 8 60 61 DOCKET NUMBER EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h Suonressor was 1012i lA damaged wiper seal was found on hydraulic suppressor 1-FW-HSS-233.

l functionally tested and found inonerable. Suppressor was on feedwater bynass line l

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l and the consequences were limited. At no time was the health and safety of the I

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io I s i i general public endangered.

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33 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h l

i o l The poppet valves which control the lock un rate were found to be imnronerly set.

I li l: l l The suporessor was renlaced with an ooerable spare suonressor.

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12141 l 80 7 8 9 OTHER STATUS IS O RY DISCOVERY DESCRIPTION STA S  % POWER Special Insnection l j,1 s [ EJ@ l0 l 9 l7 l@j NA l lC l@l ACTIVITY CONTENT LOCATION OF RELE ASE RELEASED OF RELEASE AMOUNT OF ACTIVITY i e [2]@ y@l N/A l l N/A 80 l

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NRc usc ontY ESCRIPTION O N/A 7903140 9 7 i i i l l l l l l l l _1 l =

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NAME Of PREPARER

UPDATE REPORT - Previous Report Date 02-05-79 Virginia Electric and Power Company North Anna Power Station

Attachment:

Page 1 of 1 Docket No. 50-338 Report No. LER 79-006/03X-1 Event Description While in Mode 1 operation on January 11, 1979, it was discovered that hydraulic suppressor 1-FW-HSS-233, which restrains the feedwater bypass line, had been subjected to a steady steam leak. This steam leak was from a valve bonnet on a nearby feedwater line. The steam flow caused damage to wiper seal on the piston shaft. The suppressor was then removed from the system and functionally tested. The suppressor failed to lockup in the comoression test.

Probable Consequences Of Occurrence The line restrained by the inoperable suppressor is a small line provided to bypass the main feedwater flow control valve. The suporessor is used for both seismic and occasional load effects. Since these effects did not occur during this period, the consequence of this event was very limited. At no time was the health and safety of the general public endangered.

Cause of Occurrence Though the wiper seal was damaged on the inoperable suppressor, this did not affect the suppressor's performance. The poppet valve assembly was removed and examined. An incorrect spring was installed, however, it was demonstrat.a that the suppressor would operate with this spring with the proper settings. The valve was then replaced, set for the procer lock-up rate and the suppressor retested. The suppressor's performance was satisfactory.

This suppressor was set by ITT-Grinnell before being shipped to VEPC0. The cause for the failure of this snubber was that the settings which were found were incorrect.

Immediate Corrective Action Immediately following the removal of ' ie damaged suppressor for functional testing, a spare suppressor that had been correctly calibrated and satisfactorily tested was installed.

Scheduled Corrective Action No further action required.

Action Taken To Prevent Recurrence No further action required.

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