ML19289D517

Updated RO NP-33-77-64 on 770827:reactor Coolant Pump 1-1-2 Tripped,Removing Reactor Coolant Pump from Operation.Caused by Damaged Surge Capacitors.Capacitors on All Four Reactor Coolant Pump Motors Replaced W/Units of New Design

ML19289D517
Person / Time
Site:	Davis Besse
Issue date:	09/22/1977
From:	Beeler T, Lingenfelter J TOLEDO EDISON CO.
To:
Shared Package
ML19274D938	List: ML19274D937 ML19274D939 ML19289D517
References
NUDOCS 7903070319
Download: ML19289D517 (2)

Text

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TOLEDO EDISON COMPAIN DAVIS-BESSE UNIT ONE NUCLEAR POWER STATION SUPPLEMENTAL INFORMATION FOR LER NP-33-77-64 DATE OF EVENT: August 27, 1977 FACILITY,: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE: Reactor Coolant Pump Motor 1-1-2 was declared inoperable on August 27, 1977.

Conditions Prior to Occurrence: The plant was in Mode 2, with Power (MWT) = 125 ,

and Load (MWE) = 0.

Description of Occurrence: Reactor Coolant Pump Motor 1-1-2 tripped at 1740 hours0.0201 days <br />0.483 hours <br />0.00288 weeks <br />6.6207e-4 months <br /> on August 27, 1977, with instantaneous ground (50GS) and differential current relay (87m/A-B-C) targets indicating the fault. This placed the Station into the Action Statement of Technical Specification 3.4.1 since one of the two Reactor Coolant Pumps in the loop were not in operation.

Designati., of Apoarent Cause of Occurrence: Upon inspection of the Reactor Coolant Pump 1-1-2 motor terminal box, Station maintenance personnel discove;ed It has been determined by Westing-B&C phase surge capacitors to be damaged.

house the design of the capacitor base was insufficient for the application.

Analysis of Occurrence: There was no danger to the health and safety of the public or Station personnel. The thermal power was at a low value and the re=aining three Reactor Coolant Pumps were supplying the required coolant flow.

for Corrective Action: The high flux and the flux-delta-flux setpoints were reset three pump operation as required by the Action Statement of Technical Specification 3.4.1. Station maintenance personnel replaced C-phase surge capacitors and re-installed B-phase surge capacitors after caulking the crack in the porcelsin and opening in the seam with RTV silicone sealant.

At 0058 hours6.712963e-4 days <br />0.0161 hours <br />9.589947e-5 weeks <br />2.2069e-5 months <br /> on August 31, 1977, Reactor Coolant Pump 1-1-2 was declared operable.

of Technical Specification 3.4.1.a.

This removed the station from Action Statement On August 29, 1977, an inspection was made on the remaining reactor coolant pump mctors.

A def ective capacitor was found in A phase f or Reactor Coolant Pump 1-2-2.

As Station maintenance personnel replaced A phase surge capacitor with a new one.78-470, the capacitors on al1 ~four Reactor Coolant 2 per Facility Change Request Pump motors have been replaced with new units which incorporate a new design mount-ing base as of January 20, 1979.

Failure Data: No previous shnilar events have occurred.