ML18136A320

LER 79-033/03L-0:on 791127,during Normal Operation,Personnel Observed Reduction in Flow & Pressure in Charging Pump Svc Water Subsys.Caused by Broken Stem on 1-SW-107,w/valve Disc Partially Blocking Pump Supply.Valve Replaced

ML18136A320
Person / Time
Site:	Surry
Issue date:	12/21/1979
From:	VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML18136A319	List: ML18136A318 ML18136A320 ML18136A321
References
LER-79-033-03L-01, LER-79-33-3L-1, NUDOCS 7912270560
Download: ML18136A320 (2)

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NRC FORM 366 U. Se::LEAR REGULATORY COMMISSION (7-77)

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I While Surry Unit No. 1 was in steady state operation at 100% power, Control Room persad-

[))}]* I nel observed a reduction in flow and pressure in the charging. pump service water

((II] I subsystem. This is contrary to T.S. 3.13B.2 and TS.S 3.14.A.5 and is reportable in

~ I accordance with T .S. 6. 6. 2. b. 2. The heal th and safety of the public were not affect-

[)))) I ed since the redundant train was operable.

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ITTI.J 7 8 9 80 SYSTEM CAUSE CAUSE COMP. VALVE CODE CODE SUS CODE COMPONENT CODE SUBCODE SUBCODE

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IA broken stem on l-Sw-107 caused the valve disc to drop into the suction side flow

[IJI] !path of 1-SW-P-lOA w~ich resulted in a partial blockage of the pump supply and a CIIIJ 1 reduced outlet flow £nd pressure to the charging pump service water subsystem.

DJIJ l Corrective action was taken immediately to restore the flow path.

ITE18 7 9 so FACILITY METHOD OF A STATUS ~,c PQ\~/Eri OTHER STATUS DISCOVERY DISCOVERY DESCRIPTION \:51 D:TIJ u@ l I O I O l I l0sJ N_.<l._

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e e SURRY POWER STATION, UNIT NO. 1 DOCKET NO. 50-280 REPORT NO: 79-033/031-0 EVENT DATE: 11/27/79 TITLE OF REPORT: Failure of Service Water Valve (l-SW-107)

1. DESCRIPTION OF EVENT:

W'..riile Surry Unit No. l was in steady state operation at 100% power, a reduction in charging pump service water subsystem flow and pressure was observed by Control Room personnel.

This event constitutes a condition contrary to T.S. 3.13.B.2 and T.S. 3.14.A.5, and is reportable in accordance with T.S. 6.6.2.b.(2).

2. PROBABLE CONSEQUENCES/STATUS OF REDUNDANT SYSTEMS:

The charging pump service water subsystem provides cooling water to the charging pump mechanical seal coolers and charging pump lubricating oil coolers. A complete description of the systems is contained in FSAR sections 9.4.1.4 and 9.4.3.5.

The degradation of the affected system did not have any direct safety implications. Since the redundant train was operable, the health and safety of the public were not affected.

3. CAUSE OF THE EVENT:

The valve stem was broken due to deterioration.

4. IM.'1EDIATE CORRECTIVE ACTION:

The dropped disc was removed to restore the flow pa th.

5. SCHEDULED CORRECTIVE ACTION:

The degraded valve has been replaced.

6. ACTION TAKEN TO PREVENT RECURRENCE:

None re-quired.

7. GENERIC IMPLICATIONS:

This has been identified as a generic problem. A design change package has been generated to replace all affected valves with ball valves in the Charging Pump Service Water Subsystem. The modification has been implemented on Unit 2 and Unit 1 will be completed during the SGRP outage.