ML19270F538

LER 79-006/03L-0 on 790111:damaged Wiper Seal Found on Hydraulic Suppressor 1-FW-HSS-233.Caused by Poppet Valves Which Control Lock Up Rate Being Improperly Set.Suppressor Replaced W/Operable Spare Suppressor.No Danger to Public

ML19270F538
Person / Time
Site:	North Anna
Issue date:	02/05/1979
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19270F537	List: ML19270F536 ML19270F538
References
LER-79-006-03L, LER-79-6-3L, NUDOCS 7902150400
Download: ML19270F538 (2)

Text

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[g [ A damaged wiper seal was found on hydraulic suporessor 1-FW-HSS-233. Suppressor was j O 3 i functionally tested and found inoperable. Suppressor was on feedv;ater bypass line I o 4 and the consequences were limited. At no time was the health and safety of the I o s [ general public endangered. _ l o o I o 7 I I o a l

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NAME OF PREPAHEH _

W. R. Cartwright PHONE: 703-894-5151

Virginia Electric and Power Company North Anna Power Station

Attachment:

Page 1 of 1 Docket No. 50-338 Report No. LER 79-006/03L-0 Event Description Unile in Mode 1 operation on f:ovube,' 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 compression' test.

Probable Consequences Of Occurrence The line restrained by the inoperable suppressor is a small line provided to bypass the main feedwater flow contre' valve. The suppressor is used for both seismic and occasional load effects Since those effects did not occur during this period, the consequence 01 +: event was very limited. At no time was the health and safety of the ge~ ' public endangered.

Cause Of Occurrence Though the riper 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 demonstrated that the suppressor would operate with this spring with the proper settings.

The valve was then replaced, set for the proper lock-up rate and the suppressor retested. The suppressor's performance was satisfactory. This suppressor was set by ITT-Grinnell before being shipped r VEPCO. The cause for the failure of this snubber was that the settings whic. were found were incorrect.

Immediate Corrective Action Immeciately following the removal of the damage 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 rcluired.