05000458/LER-1985-006, :on 850916,reactor Protection Sys Actuated While in Noncoincident Trip Mode When Malfunction in Undervoltage Printed Circuit Board on Alternate Supply Breaker Tripped Electrical Protection Assembly

:on 850916,reactor Protection Sys Actuated While in Noncoincident Trip Mode When Malfunction in Undervoltage Printed Circuit Board on Alternate Supply Breaker Tripped Electrical Protection Assembly

ML20138B917
Person / Time
Site:	River Bend
Issue date:	10/15/1985
From:	Kosmala R GULF STATES UTILITIES CO.
To:
Shared Package
ML20138B899	List: 05000458/LER-1985-006, :on 850916,reactor Protection Sys Actuated While in Noncoincident Trip Mode When Malfunction in Undervoltage Printed Circuit Board on Alternate Supply Breaker Tripped Electrical Protection Assembly 05000458/LER-1985-007, :on 850919,replacement Level Transmitter for Scram Discharge Vol Did Not Meet IEEE Std 323-1974 Qualifications.Caused by Maint Personnel Not Using Controlled Documents to Specify Replacement
References
LER-85-006, LER-85-6, NUDOCS 8510220078
Download: ML20138B917 (2)

LER-1985-006, on 850916,reactor Protection Sys Actuated While in Noncoincident Trip Mode When Malfunction in Undervoltage Printed Circuit Board on Alternate Supply Breaker Tripped Electrical Protection Assembly

Event date:
Report date:
4581985006R00 - NRC Website

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At 07S7 on 9-16-85, with the unit suberitical, the Reactor Protection System (RPS) actuated while in the non-coincident trip mode for fuel loading.

RPS Channel A was in the alternate power feed mode to support Division I Emergency Core Cooling System testing during which a spurious trip on an electrical protection assembly in the RPS Channel A alternate power feed occurred.

RPS Channel A was switched to the normal supply and the trip was reset.

The cause was due to a malfunction in the undervoltage printed circuit board on the alternate supply breaker. The breaker was repaired on 9-20-85 and returned to service.

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anc w m.w on At 0757 on 9-14-85, with the unit ~suberitical, the Reactor Protection System (RPS) actuated while in the non-coincident trip mode for fuel loading. RPS Channel A was in the alternate power feed mode to support Division I Emergency Core Cooling System testing during which a spurious trip on an Electrical Protection Assembly (EPA)

C71*S003E in the RPS channel A alternate power feed occurred.

The breaker had experienced spurious trips before and Maintenance Work Request (MWR) No. 8770 (8-26-85) and MWR No. 8516 (8-27-85) were written to investigate the problem.

Investigation on 8-26-85, 8-27-85, and 8-28-85 showed no apparent problem.

On 9-19-85 the cause of the breaker spurious trip was traced to a malfunction in the undervoltage timer section of the electrical protection logic card (GE 47D523796G1 S/N 185).

Remedial corrective action was to place RPS channel A on the normal power supply and reset the RPS actuation.

Generic corrective action to correct the problem with the breaker was to replace the printed circuit board. The printed circuit board was tested and returned to service.

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