05000339/LER-1980-092-03, /03L-0:on 801103,train B of Safety Injection Sys Failed to Reset Following Functional Test.Caused by Binding in Latching Mechanisms Resulting in Failure of Relays to Reset.Relays Cleaned & Tested Satisfactorily

/03L-0:on 801103,train B of Safety Injection Sys Failed to Reset Following Functional Test.Caused by Binding in Latching Mechanisms Resulting in Failure of Relays to Reset.Relays Cleaned & Tested Satisfactorily

ML19345B841
Person / Time
Site:	North Anna
Issue date:	11/24/1980
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19345B835	List: 05000339/LER-1980-092, Forwards LER 80-092/03L-0 05000339/LER-1980-092-03, /03L-0:on 801103,train B of Safety Injection Sys Failed to Reset Following Functional Test.Caused by Binding in Latching Mechanisms Resulting in Failure of Relays to Reset.Relays Cleaned & Tested Satisfactorily
References
LER-80-092-03L, LER-80-92-3L, NUDOCS 8012020602
Download: ML19345B841 (2)

LER-1980-092, /03L-0:on 801103,train B of Safety Injection Sys Failed to Reset Following Functional Test.Caused by Binding in Latching Mechanisms Resulting in Failure of Relays to Reset.Relays Cleaned & Tested Satisfactorily

Event date:
Report date:
3391980092R03 - NRC Website

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4 U.S. NUCLEAR REGULATORY COBE!ISSION LICUSEE EVENT REPORT

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(PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION)

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LICENSEE CODE LICENSE NUMBER LICENSE TYPE CAT

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

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On November 2,1980, while in Mode 5, the Train B of the Safety Injection sys- /

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tem failed to reset following a functional test.

Since the unit was in Mode 5 /

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and the equipment operable if required, the health and safety of the public

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were not affected. This item is reportable pursuant to T. S. 6.9.1.9.d.

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SYSTEM

CAUSE

CAUSE COMP.

VALVE CODE CODE SUBCODE COMPONENT CODE SUBCODE SUBCODE

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SEQUENTIAL OCCURRENCE REPORT REVISION LER/R0 EVENT YEAR REPORT NO.

CODE TYPE NO.

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ACTION FUTURE EFFECT SHUTDOWN ATTACHMENT NPRD-4 PRIME COMP. COMPONENT TAKEN ACTION ON PLANT METHOD H0l'IS SUBMITTED FORM SUB. SUPPLIER MANUFACTURER

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CAUSE DESCRIPTION AND CORRECTIVE ACTIONS (27)

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The failure of several relays to reset prevented the manual stopping of operat-/

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ing equipment from the control board. The relays did not reset because of

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binding in the latching mechanisms. The relays were cleaned and tested

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satisfactorily.

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FACILITY METHOD OF STATUS

% POWER OTHER STATUS DISCOVERY DISCOVERY DESCRIPTION (32)

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ACTIVITY CONTENT RELEASED OF RELEASE AMOUNT OF ACTIVITY (35)

LOCATION OF RELEASE (36)

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PERSONNEL EXPOSURES NUMBER' TYPE DESCRIPTION (39)

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PERSONNEL INJURIES NUMBER DESCRIPTION (41)

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LOSS OF OR DAMAGE TO FACILITY (43)

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PUBLICITY l

ISSUED DESCRIPTION (45)

NRC USE ONLY

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VA

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NAME OF PREPARER W. R. CARTWRIGHT PHONE (703) 894-5151 l8012 0 2'O dro A

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Virginia Electric'and Power Company North Anna Power Station, Unit 2 Attachment: Page 1 of 1 Docker No. 50-339 Report No. LER 80-092/03L-0

Description of Event

On November 2,1980, while perfonsing periodic test (1-PT-57.4 '-

Safety Injection System Functional Test), train B of the safety injection system failed to reset. The relays that failed to reset were K603, K604 and K611. These relays' prevented 2-SI-P-1B, and 2-FW-P-3B and several valves from being de-energized or returned to their normal position from the control board when the safety injection signal was reset.

Probable-Consequences of Occurrence The consequences of.this event were limited since all equipment required for safety injection operated satisfactorily. To recover from the test, the pumps were secured by manual control at'their breakers and valves were manually repositioned. Since the unit'was in Mode 5 when this test was conducted,'the health and safety of the public were not affected.

Cause of Event

The latching mechanism mounted on the relay energized to latch the relay into position but would not unlatch due to binding in'the mechanism.

This prevented the relays from being reset. The latching mecnanism is a ARLA type 4993D05G06 and-is mounted on the relay type AR440A. Both are manufactured by Westinghouse.

Immediate Corrective Action

The immediate_ corrective was to remove, clean and functionally test the latching mechanism.

Scheduled Corrective Action.

The manufacturer's representative has been contacted for an investi-gation into this event.

Actions Taken to Prevent Reccurrence Further actions to prevent recurrence will be taken when a satisfac-tory modification or design change is developed.

Generic Implications The failure of the latching mechanism to reset has occurred several' times. Therefore, these repetitive failures have_ implied a generic problem with this ' type of latching mechanism.