05000261/LER-1981-017-03, /03L-0:on 810619,auxiliary Feedwater Pump a Tripped on Low Discharge Pressure.Caused by Improper Throttle Setting of Discharge Valve.Valve Repositioned

/03L-0:on 810619,auxiliary Feedwater Pump a Tripped on Low Discharge Pressure.Caused by Improper Throttle Setting of Discharge Valve.Valve Repositioned

ML20009E556
Person / Time
Site:	Robinson
Issue date:	07/16/1981
From:	Cox H CAROLINA POWER & LIGHT CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20009E539	List: 05000261/LER-1981-017, Forwards LER 81-017/03L-0 05000261/LER-1981-017-03, /03L-0:on 810619,auxiliary Feedwater Pump a Tripped on Low Discharge Pressure.Caused by Improper Throttle Setting of Discharge Valve.Valve Repositioned
References
LER-81-017-03L, LER-81-17-3L, NUDOCS 8107280300
Download: ML20009E556 (3)

LER-1981-017, /03L-0:on 810619,auxiliary Feedwater Pump a Tripped on Low Discharge Pressure.Caused by Improper Throttle Setting of Discharge Valve.Valve Repositioned

Event date:
Report date:
2611981017R03 - NRC Website

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LICENSEE EVENT REPORT CONTROL BLOCx: l l

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8 60 61 DOCKET NUMB ER 68 69 EVENT DATE 74 75 REPORT D ATE 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h Io l2l l0n June 19,1981, at 1717 hours0.0199 days <br />0.477 hours <br />0.00284 weeks <br />6.533185e-4 months <br />, with the ucit at 0% power following a reactor trip, l

[ rm l"A" Auxiliary Feedwater (AW) Pump tripped cn low discharge pressure resulting from l

Io lel l improper throttle setting of the discharge valve.

The valve was repositioned, and the l lo isl l pump restarted.

"B" AW pump was supplying the necessary feedwater so there was no l

I O ls l Ithreat to the public health and safety.

Since the Stea:'t Driven AW pump was out-of-l lol7j l service, this event resulted in a degraded mode of operation permitted by Technical l

l o is l l Specification 3.4.3 which is reportable pursuant to 6..".2.b.2.

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- AW pump trip was caused bv low discharce cressure resultinc from Moroner throttlel l i t i l tsetting of the discharge valve.

The valve was repositioned to the proper discharge 1

I i i 2 I l pressure setting, and the pump was restarted satisfactorily.

The operating procedures,1

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l i l 31 lwhich did not provide sufficient information, have been revised to clarify proper valvel ii i A i l position setting. No further action is considered necessary.

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NAME OF PREPARER

Item 10 on June 19, 1981, at 1717 hours0.0199 days <br />0.477 hours <br />0.00284 weeks <br />6.533185e-4 months <br />, with the unit at 0% power following a reactor trip, "A" Auxiliary Feedwater (AW) Pump tripped on low discharge pressure resulting from improper throttle setting of the discharge valve.

The valve was repositioned, and the pump restarted.

"B" AW pump was supplying the necessary feedwater so there was no threat to the public health and safety.

Since the Steam Driven AW pump was out-of-service, this event resulted in a degraded mode of operation permitted by Technical Specification 3.4.3 which is reportable pursuant to 6.9.2.b.2.

Item 27 The AW pump trip was caused by low discharge pressure resulting from improper thattle setting of the discharge valve.

The valve was repositioned to the proper discharge pressure setting, and the pump was restarted satisfactorily.

The operating procedures, which did not provide sufficient information, have been revised to clarify proper valve position setting.

No further action is considered necessary.

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SUPPLEMENTAL INFORMATION FOR LICENSEE EVENT REPORT 81-17 1.

Cause Description and Analysis on June 19, 1981, at 1711 hours0.0198 days <br />0.475 hours <br />0.00283 weeks <br />6.510355e-4 months <br />, with the unit at 0% power following a reactor trip, "A" and "B" Auxiliary Feedwater (AFW) pumps started auto-matically as required. At 1717 hours0.0199 days <br />0.477 hours <br />0.00284 weeks <br />6.533185e-4 months <br /> "A" AFW pump trisped due to low discharge pressure. Further investigation revealed '.nat the low pres-sure was caused by an improper throttle setting on the discharge valve (AFW-45) which allowed pump cavitation to occur.

"A" AFW pump had been out of service for maintenance on the discharge check valve and motor operated valve on June 18, 1981, while the plant was at 93% power.

Following this maintenance effort, the pump was tested, using the re-circulation line as a flow path, and returned to service.

However, since the operating procedures did not specify the valve settings to be used when the unit is at power (93%), AFW-45 was repositioned using the discharge valve position on "b" AFW pump as a guide. Apparently there were sufficient differences between the two pumps and their dis-charge valves that this approach was inadequate. After tripping on June 19, 1981, "A" AFW pump was restarted at 1928 hours0.0223 days <br />0.536 hours <br />0.00319 weeks <br />7.33604e-4 months <br /> and AFW-45 was repositioned using direct pressure indication while feeding the steam generators.

During this event, "B" AFW pump was operating and supplying 100% of the necessary feedwater.

For this reason, there was no threat to the public health and safety.

Since the Steam Driven AFW pump was out of service for maintenance at this time, the failure of "A" AFW pump resulted in a degraded mode of operation permitted by Technical Specification 3.4.3, which is reportable pursuant to 6.9.2.b.2.

2.

Corrective Action

The immediate corrective action was to restart the pump and adjust the discharge valve using the pump discharge pressure to establish the proper setting.

To insure operability, Periodic Test 22.lA was per-formed satisfactorily, and "A" AFW pump was declared in service June 19, 1981, at 1947 hours0.0225 days <br />0.541 hours <br />0.00322 weeks <br />7.408335e-4 months <br />.

3.

Corrective Action To Prevent Recurrence The procedures, General Procedure-2, Operating Procedure-14, and Operating Work Permits AFW-1 aad AFW-2 have been revised and an operating curve for the AFW pumps was added to the Curve Book (POM Volume 15). The revisions and addition of an operating curve clarify the method by which the discharge valves are positioned under all operating conditions, thereby insuring operability of the AFW pumps.

Although these actions are considered entirely adequate to prevent recurrence, this event will be reviewed as part of an on-going general review of the AFW system. Any additional corrective actions related to this event which results from *he review will be reported in a revision to this LER.

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