ML19289D791

LER 79-018/03L-0 on 790214:during Mode 1 Operation at 98% Power,Main Steam Trip Valve 1-TV-MS-111B Leaked Excessively & Was Isolated for Repair.Caused by Deteriorated Internal Gasket.Valve Isolated & Gasket Replaced

ML19289D791
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-79-018-03L, LER-79-18-3L, NUDOCS 7903140418
Download: ML19289D791 (2)

Text

g LICENSEE EVENT REPORT (PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION)

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DATE 80 7 8 60 61 DOCK ET NUMBER EVENT oESCRIPTION AND PROB ADLE CONSEQUENCES h '

o 2 lDuring Mode 1 operations at 98% power, main steam trip valve 1-TV-MS-lllB was found l i o i3, i to leak thrcagh excessively and was isolated for repair. This valve is located on the o 4 l main steam line leading to the steam driven steam generator auxiliary feedwater cump l o 3  ;(1-FW-P-2). Isolation of the valve made the pump inoperable. Reportable pursuant to l o o ;T.S. 6.9.1.9,b. g Io I7I I I O 8 l 80 7 8 9 C DE CODE SUBCO E COMPONE NT CODE SUBC dE SU E o 9 lH j B j@ {@ {@ l Vl Al L l V l E l X l@ Q@ lD l@ 18 19 20 7 8 9 10 11 12 13 SEQUENTIAL OCCURRENCE REPORT REVISION EVENT YE AR REPORT NO. CODE TYPE N O.

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, o gThe leak was caused by a deteriorated internal gasket. The valve was 1solated and gi,,,[the gasket was replaced. g I

i 2 I 1 3 1 4 l 7 8 9 80 ST A S  % POWER OTHER STATUS DIS O RY DISCOVERY DESCRIPTION i 5 [,E_J @ l 01 91 9l@ l NA l lAl@lOperatorObservation l A TlVITY CO TENT RELEASED OF RELE ASE AMOUNT OF ACTIVITY LOCATION OF RELEASE 7

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NAME Of PREPAREH PetONE:

Virginia Electric and Power Company North Anna Power Station, Unit No.1

Attachment:

Page 1 of 1 Docket No. 50-338 Report No. LER 79-018/03L-0 Description of Event During Mode 1 operations, at 98% power, trip valve 1-TV-MS-111B was detected as leaking through. This valve is on the steam line leading to the steam driven steam generator auxiliary feedwater pump (1-FW-P-2). A maintenance report was submitted on the valve to effect a repair which required isolating the valve and the steam supply to the pump.

Probable Consequences of Event The steam line to the feedwater pump required isolation thereby bringing into effect the action statement of T.S. 3.7.1.2. This calls for one of three auxiliary feedwater pumps to be powered by an operable steam supply within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> of shutoff or to be in Hot Shutdown within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. The other two motor driven feed pumps were operable and 1-FW-P-2 was returned to service within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. During repair of the trip valve, redundant valve 1-TV-MS-111A remained operable, making the steam supply to the steam driven pump still available. Therefore, the health and safety of the public were not endangered.

Cause The leak was caused by a deteriorated gasket within the valve.

Immediate Corrective Action The valve was isolated and the faulty gasket was replaced.

Scheduled Corrective Action No further action required.

Action Taken To Prevent Recurrence The vendor has recommended a new type gasket for this valve. An engineering study will be performed to determine if the new type should be utilized.

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