05000280/LER-1981-037-03, /03L-0:on 810806,charging Pump Svc Water Pumps 1-SW-P-10A & B Found to Have Zero Discharge Pressure Due to Loss of Suction to Pumps.Caused by Increased Use of Svc Water by Chillers During Summer Months.Strainers Cleaned

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/03L-0:on 810806,charging Pump Svc Water Pumps 1-SW-P-10A & B Found to Have Zero Discharge Pressure Due to Loss of Suction to Pumps.Caused by Increased Use of Svc Water by Chillers During Summer Months.Strainers Cleaned
ML20010F108
Person / Time
Site: Surry Dominion icon.png
Issue date: 09/01/1981
From: Joshua Wilson
VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20010F102 List:
References
LER-81-037-03L-03, LER-81-37-3L-3, NUDOCS 8109090378
Download: ML20010F108 (3)


LER-1981-037, /03L-0:on 810806,charging Pump Svc Water Pumps 1-SW-P-10A & B Found to Have Zero Discharge Pressure Due to Loss of Suction to Pumps.Caused by Increased Use of Svc Water by Chillers During Summer Months.Strainers Cleaned
Event date:
Report date:
2801981037R03 - NRC Website

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o CAUSE DESCRIPTION AND CORRECTIVE ACTIONS I s iel l During the summer months, the increase us< of service water hv the chillers can causet t iil t a loss of suction pressure to the charging pump service water pumps.

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ATTACHMENT l' SURRY POWER STATION, UNIT ~ l DOCKET NO:-

50-280

' REPORT NO:

81-037/03L-0 EVENT DATE:

08-06-81 l-TITLE OF THE EVENT:

SERVICE WATER PUMPS, SW-P-10A,10B, LOSS OF SUCTION 1.

' DESCRIPTION OF EVENT:

With the Unit at 100% power, the charging pump service water pumps 1-SW-P-10A and 10B' were found to have zero discharge pressure.' The pumps were secured and -

the strainers ins [ucted. The "A" pump was restarted and operated satisfactorily.

Shortly thereaf ter, the "B" pump was restarted and the "A" pump returned to Automatic.

On August 10, R.e"B" charging pump service water pump again experienced a loss of suction pressure. The service water to the chiller was reduced and the pump restarted.

On August 14, while performing PT 18.8 (charging pump component cooling and service water perforn.cnce), the "B" service water pump was started and I he "A" pump secured. The "B" pump failed to provide adequate discharge pressure and the "A" pump was restarted. The suction strainer was inspected and verified clear. The service water to the chillers was then throttled and the "B" pump restarted with satisfactory discharge pressure.

On August 18,1-SW-P-10A started in auto and an operator was sent to clean the suction strainers. To provide adequate suction pressure, the service water to 1-VS-E-4C was throttled. Approximately two hours later, while adjusting the chiller service water, the 2nd pump again started on low discharge pressure.

When the chiller service water flows were readjusted, the _"B" pump was returned to auto.

I Inoperability of the charging pump service water pumps is contrary to T.S.-

3.3.A.8.b and is reportable in accordance with T.S.-6.6.2.b.(?).

2.

TR0BABLE CONSEOUENCES AN" STATUS OF REDUNDANT EOUIPMENT:

The charging pump service water pumps rupply' cooling water to the, charging pump intermediate seal oil coolers and the charging pump lubricating oil coolers. During the short periods when these pumps were inoperable, a maximum of 20 minutes, the charging pump temperature did not show any temperatuce increases.

In all cases, the pumps were restored to service within the time limits of T.S.-3.3.B.6 nnd 3.0.1; therefore, the health and safety of the public sere not affected.

3.

CAUSE

The service water piping for the charging pump service water pumps also supplies the Cont ol Room / Relay Room air conditioner chiller unite 1-VS-E-4A, B. and C.

During tis summer months the increased use of service water by the chillers can cause a Ic s of suction pressure to the charging pump service water pumps.

Recent moci.'ications (DC 80-42) attempted to resolve the NPSH problems for the service water system.

Installation and Testing, completed in early spring, indicated satisfactory performance, however, an intermittent problem is now indicsted.

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~PAGE 2 of Att'achment 1.

REPORT NO:

81-037/03L-0:

4.

- IMMEDIATE CORRECTIVE-ACTION:

The suction strainers'were checked and/or cleaned and the serive water to the

. chillers was throttled to increase the flow to the charging pump. service water

. pumps.

5.

SUBSEQUENT CORRECTIVE ACTION:

None tr. ken.

6.

ACTION TAKEN TO PREVENT RECURRANCE:

Furthet-evaluation will be conducted to determine'. if additional modifications are required to resolve the marginal NPSH Conditions.

7.

GENERIC IMPLICATIONS:

This is generic to both units. A related. occurrence is reported on LER

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81-051/0'lL-0 for Unit 2.

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