ML20086C644

Special Rept:On 950523,Unit 1 Train a Fuel Handling Ventilation Filter Heaters Declared Inoperable.Evaluation Done to Determine Fault

ML20086C644
Person / Time
Site:	Catawba
Issue date:	06/29/1995
From:	Rehn D DUKE POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9507070213
Download: ML20086C644 (2)

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Catawba kclear Generation Department lice President l 4800 CoscordRoad (803)8314205 Omce York, SC29745 (803)8313426 Fax DUKEPOWER I

i June 29,19952 U. S. Nuclear Regulatory Commission i

! ATTN: Document Control Desk l Washington,DC 20555

Subject:

Catawba Nuclear Station, Unit 1 Docket No. 50-413 Fuel Handling Ventilation Filter Heaters Inoperable Greater Than 7 Days Special Report Pursuant to Catawba Nuclear Station Technical Specification 3.9.11 Action b., find attached a Special Report concerning the inoperability of the Unit 1 Train A Fuel Handling Ventilation filter heaters. The heaters were declared inoperable on May 23,1995.

Sincerely, D. L. Rehn Attachment KEN /SRHTR629.95 xc: S. D. Ebneter, Regional Administrator, Region II R. E. Martin, Oh%R Senior Resident Inspector R. J. Fredenberger, SRI 1

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SPECIAL REPORT CATAWBA NUCLEAR STATION  !

UNIT 1 TRAIN A FUEL HANDLING VENTIL ATION l FILTER HEATERINOPERABLE FOR MORE'l ' N 7 DAYS i i

Catawba Technical Specification 3/4.9.11 requires at least one train of the Fuel Handling Ventilation Exhaust System to be operable with irradiated fuel in the storage pool. With the heaters inoperable, restoration must be made within 7 days, otherwise, a special report must be  ;

submitted. i i

While troubleshooting the cause of a low temperature on the Fuel Handling Area Ventilation .

l (VF) Filter Train l Al, Instrument and Electrical (IAE) personnel discovered evidence (soot and -f traces of melted copper) of electrical arcing in the breaker compartment IEMXI-F05D, which supplies this load. There were indications of an existing high impedance ground fault. The source of the ground appeared to be an alignment wheel screw in the bottom of the compaitment penetrating an internal cable, located between the vertical bus and the line side of the breaker. l Subsequent investigations revealed the screw head was partially incinerated and embedded in the l cable insa lation. The conductor had separated into two parts, approximately one inch apart. l l

A phase to ground fault on breaker 1EMXI-F04C (VF Htr 1 Al Brkr) line side cable resulted in a power loss to the system VF filter unit heater (FPFU-1 Al). This heater was declared inoperable l' on 05/23/95, and entered into Technical Specification Action Item Logbook under #Cl 01649.

O An evaluation was done to determme if the fault and subsequent degraded condition of the cable l created past operability concerns in regards to the ability of the 600 VAC Essential Auxiliary Power System (EPE) to perform its function under design basis events. This evaluation determined the EPE System was operable while the ground fault existed. [

Repairs to motor control center compartment breaker IELXC-4C were completed on 06/22/95, under work order 95042590-01. Subsequent voltage data indicated that no additional faults existed. No present operability concerns exist for this equipment. The VF heater breaker l Al is currently scheduled for performance testing by the Operations Test Group on 07/11/95. Testing l is expected to be completed by 07/31/95 and the system would then be restored to operable status. j

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