05000339/LER-1980-099-03, /03L-0:on 801210,overspeed Trip of Steam Driven Auxiliary Feedwater Pump Occurred During post-maint Testing. Probably Caused by Governor Malfunction Due to Air Entrapment.Air Purged from Governor Oil

/03L-0:on 801210,overspeed Trip of Steam Driven Auxiliary Feedwater Pump Occurred During post-maint Testing. Probably Caused by Governor Malfunction Due to Air Entrapment.Air Purged from Governor Oil

ML19351F575
Person / Time
Site:	North Anna
Issue date:	01/06/1981
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19351F562	List: 05000339/LER-1980-099, Forwards LER 80-099/03L-0 05000339/LER-1980-099-03, /03L-0:on 801210,overspeed Trip of Steam Driven Auxiliary Feedwater Pump Occurred During post-maint Testing. Probably Caused by Governor Malfunction Due to Air Entrapment.Air Purged from Governor Oil
References
LER-80-099-03L-01, LER-80-99-3L-1, NUDOCS 8101130528
Download: ML19351F575 (2)

LER-1980-099, /03L-0:on 801210,overspeed Trip of Steam Driven Auxiliary Feedwater Pump Occurred During post-maint Testing. Probably Caused by Governor Malfunction Due to Air Entrapment.Air Purged from Governor Oil

Event date:
Report date:
3391980099R03 - NRC Website

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U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT C0hTROL BLOCK / / / / / / / (1)

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CE DOCKET NUMBER EVENT DATE REPORT DATE EVEh7 DESCRIPTION AND PROBABLE CONSEQUENCES (10)

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On December 10, 1980, with Unit 2 in hot standby, an overspeed trip of the

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steam driven auxiliary feedwater pump occurred during post maintenance testing./

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This event is reportable pursuant to T.S. 6.9.1.9.b.

Two redundant motor

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driven auxiliary feedwater pumps were available. The Action Statement of the /

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LCO (T.S. 3.7.1.2) was met.

The public health and safety were not affected.

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SYSTEM

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ACTION FUTURE EFFECT SHUTDOWN ATTACHMEhT NPRD-4 PRIME COMP. COMPONEh7 TAKEN ACTION ON PLAh7 METHOD HOURS SUBMITTED FORM SUB. SUPPLIER MAhTFACTURER

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CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (27)

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The suspected cause of the overspeed trip is a governe r malfunction caused by /

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air entrapment in the governor oil. ' Air was purged from the governor oil and /

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the pump was successfully retested four times.

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FACILITY METHOD OF STATUS

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Routine Test

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NAME OF PREPARER W. R. CARTWRIGHT PHONE (703) 894-5151 011s0 W s1

Virginia Electric and Power Company North Anna Power Station, Unit 2 Attachment: Page 1 of 1 Bocket No. 50-339 Report No. LER 80-099/03L-0

Description of Event

On December 10, 1980, with Unit 2 in Hot Standby, an overspeed trip of the steam driven auxiliary feedwater pump occurred during post mainte-nance testing. This event is reportable pursuant to T.S. 6.9.1.9.b.

Probable Consequences of Occurrence Two motor driven auxiliary feedwater pumps were operable when the event occurred. The steam driven pump was returned to a operable status within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />. The action statement for the LCO (T.S. 3.7.1.2) was met.

The public health and safety were not affected.

Cause of Event

When the steam driven auxiliary steam driven pump was started, the governor began hunting. Overshoot of the governor caused the pump to trip on overspeed. Governor hunting can be caused by air entrapment in the governor oil. During an investigation of the event a one gallon container of governor oil was found in the auxiliary feedwater pump house and a light coat of new oil around the governor oil fill cap was noted indicating that a recent oil addition had been made to the governor.

Since evidence indicated a recent oil addition to the governor had been made, the suspected cause of pump overspeed trip is governor malfunction caused by air entrapment in the governor oil.

Immediate Corrective Action

Suspecting that air entrapment in the governor oil was causing the l

problem, the Unit 2 Shift Supervisor reduced the governor setpoint and

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ran the pump until the governor stopped hunting and stabilized. Steady l

governor control indicated that the governor oil had been purged of air.

l The governor setpoint was returned to its specified value and the pump l

was successfully restarted three times. The pump was then tested satis-l factorily in accordance with a periodic test which included T.S. and IWP l

requirements prior to being declared operable. The testing frequency of the pump was doubled and the puap successfully passed tests on December 13, and 20, 1980.

Scheduled Corrective Action Maintenance procedures have been changed to include steps for adding oil and properly purging air from the governor.

Actions Taken to Prevent Recurrence The scheduled corrective actions described above should prevent recurrence.

l Generic Implications This event had no generic implications.

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