ML20072P826

Special Rept:On 901012,two Invalid Failures of Diesel Generator 1a Occurred.Caused by Kd Outlet High Temp Sensor (1KD Tt 5000) Venting

ML20072P826
Person / Time
Site:	Catawba
Issue date:	11/09/1990
From:	Tuckman M DUKE POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9011280042
Download: ML20072P826 (2)

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llake 1%urr Congany (701137340ll Nuclear l'roductiva lirtsartment l'O flar 100*

Churiotte, k:2b201 100i OUKEPOWER November 9, 1990 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555

Subject:

Catawba Nuclear Station, Unit 1 Docket No. 50-413 Special Report Gentlemen:

Pursuant to Technical Specifications 6.9.2 and 4.8.1.1.3, please find attached a Special Report concerning Unit 1 Diesel Generator 1A invalid failures on October 12, 1990, respectively.

Very truly yours,

,s  ; ,

</ b& 5 ,,ocsc,n5ar s,

M. S. Tuckman, Vice President Nuclear Operations MHH-2/lcs Attachment xc: Mr. S. D. Ebneter Regional Administrator, RII-U. S. Nuclear Regulatory Commission 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia- 30323 Mr. R. E. Martin Of fice of Nuclear Regulatory itegulation U. S. Nuclear Regulatory Commission One White Flint North, Mail Stop 9H3 Washington D.C. 20555

'Mr. W. T. Orders NRC Resident Inspector Catawba Nuclear Station I

9011280042 901109 PDR ADOCK 05000413 S PDC ll{\

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k SPECIAL REPORT GATAWBA NUCLEAR STATION D/G 1A INVALID FAILURES DUE TO A FAULTY JACKET WATER OUTLET TEMPERATURE SENSOR t Two invalid failures of Diesel Generator (D/G) 1A occurred on October 12, 1990, while Unit 1 was at 100% power. D/G 1A was on a monthly test schedule

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at the time of the invalid failures. There has been 0 valid failures in the last 20 valid tests and 1 valid failure in the last 100 valid tests on D/G 1A.

D/G 1A was declared inoperable on October 10, 1990, at 0024 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, for proplanned maintenance. Following the maintenance, on October 12, 1990, at 0043 hours4.976852e-4 days <br />0.0119 hours <br />7.109788e-5 weeks <br />1.63615e-5 months <br />, OPS initiated (Start #848) per OP/1/A6350/02 Diesel Generator Operation) to perform a functional verification on the maintenance performed. Approximately 60; seconds into the run, the D/G tripped. The operator received several non-emergency trip annunciators at the time. The Shift.then generated a high priority work request (54251 OPS) to investigate the trip.

The D/G was then restarted (Start.#849) per OPS procedure with IAE present

'to determine the cause of the trip. This process revealed that the KD outlet High' Temperature sensor (1KD TT 5000) was venting. During the engine ,

'startup with sensor ve' ting, the pneumatic non-emergency trips were not able  ;

to be pressurized above the 40 psig' trip setpoint prior to the 60 second time delay. The non-emergency trips are bypassed _during the initial 60 '

seconds to allow the. pneumatic lines time to pressurize to a normsl 60 psig.

The rensor was removed and found to be out-of calibration. The sensor had

- been recalibrated earlier per 10244 SWR, during scheduled preventative maintenance.- The sensor was found to be on the high side out of calibration, and was successfully recalibrated. Because of this earlier maintenance, a new sensor was calibrated and installed on the.D/G. .The D/G-was then started twice by Operation's. procedure and ran to ensure the-D/G would not' trip (Start:#850 & #851). Following the repair the'D/G was-

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secured, then restarted'per PT/1/A/4350/02A1(D/G'1A Operability).and ran loadedLat 5700 Kw for ove'r:1 hour _with no: problems. The D/G was then L declared operable on October'12, 1990:at 1800.

'The sensor that failed is associated with the pneumatic non-emergency side

-of the D/G circuitry. It_is not associated with the electronic emergency q L side of the run circuitry. In the event'of an emergency demand of the D/G.

,the penumatic non-emergendy side of the run. circuitry would have been-bypassed and the D/G'would have functioned as. designed.  ;

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