ML20099B982

Special Rept:On 920624,Train B Filter Unit Declared Inoperable for Surveillance Testing & Temp Switch Would Not Calibr During Surveillance.Caused by Calibr Drift Problems. Switches Will Be Removed During Station Mods in 1993

ML20099B982
Person / Time
Site:	Catawba
Issue date:	07/24/1992
From:	Tuckman M DUKE POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9208030207
Download: ML20099B982 (2)

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, thM Con:ord Roa1 (8n118313 t'5 Difue kvk. SC:9745 (Mt0LU)J(26 In DUKEPOWER July 24,1992 U. S. Nuclear Regulatory Commission ATrN: Document Control Desk Washington, DC 20555 j

Subject:

Catawba Nuclear Statha, Unit 2 Docket No. 50-414 Fuel Handling Ventilation Filter Heaters Inopeable Greater Than 7 Days Special Report Pursuant to Catawba Nuclear Station Technical Specification 3.9.11 Action b., find attached a i

Specal Report concerning the inopembility of the Unit 2 Train B Fuel Handling Ventilation filter heaters. The heaters were declared inoperable on June 24,1992.

y Very tmly yours, bb. c .

M. S. Tuckmaa Attachment MHH/SRHTR xc: S. D. Ebneter Regional Administrator, Region II W. T. Orders Senior Resident Inspector R. E. Martin, ONRR "0010;i tI w w .w v 9208030207 920724 7 PDR ADOCK 05000414 S PDR y%8-

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,. SPECIAL REPORT CATAWBA NUCLEAR STATION UNIT 2 TRAIN B FUEL HANDLING VENTILATION FILTER IIEATER INOPERABLE FOR MORE TIIAN 7 DAYS Catawba Technical Specificaiion 3/4.9.11 requires at least one train of the Fuel Handling Ventilation Exhaust System to be opemble with irmdiated fuel in the storage pool. With the heaters inoperable, restoration must be made within 7 days, othenvise, a special report must be submitted.

On June 24,1992, Train B Filter Unit associated with Reactor. Unit 2 was declared inoperable

.or survehiance testing of the associated heater control instrumentation. Temperature switch 2VFTS5990_. which opemtes to de-energize Fuel Pool Filter Unit 2B2 heaters on a high temperature, would not calibrate during the surveillance. Qualified temperature switches can ao longer be purchased for use at the station, and the warehouse stock has tren depleted. The switch was supplied I;y Industrial Engineering and Equipment Company (INDEECO) as part of the heater assembly. Duke Power purchased the assembly as pan of the Glter train package from Mine Safety Appliances Company (MSA). The temperature switch, alcng with the heaters.

are classified as Nuclear Safety Related/QA Condition 1 componec.

g Calibration drift problems were previously identified with these tempemture switches in early 1990. Due to this problem, the setpoints were raised to a value that would not cause the heaters to become inoperable. This was a temporary measure until a final resolution could be implemented. Station Problem Report No. CNPR 4900 was initiated to completely remove the switches from the heater controls. Nuclear Station Modifications (NSM) are planned to be imple:nented in 1993 to remove these switches from the affected ventilation systems.

Due to the failure of 2VFTS5990, Station Problem Report No. CNPR-6341 wac initiated on June 29, 1992 to allow removal of this switch from the heater controls before the NSM is planned to be implemented. Due to the presert outage work, an exempt change will be initiated in October-November 1992 to remove the switch. This will ensure the appropriate actions are taken before movement of Unit 2 fuel takes place during the Unit 2 refueling outage in early_

1993. Satisfactory completion will thus render the Unit 2 Fuel Pool Wntilation System Train B heaters to operable status.