ML20066J494

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Special Rept:On 910116,while Closing D/G Breaker When Synchronizing Energized Bus,Invalid Failure of D/G 2A Occurred.Caused by Operator Hesitation.New Operators Will Perform Paralleling & Loading as Part of Training
ML20066J494
Person / Time
Site: Catawba Duke Energy icon.png
Issue date: 02/15/1991
From: Tuckman M
DUKE POWER CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9102260247
Download: ML20066J494 (2)


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DUKE POWER February 15, 1991 U. S. Nuclear Regulatory Commission i

AlTN: Document Control Desk Washington, D.C.

20555

Subject:

Catawba Nuclear Station, Unit 2 Docket No. 50-414 Special Report Invalid Failure Diesel Generator 2A Pursuant to Technical Specification 4.8.1.1.3 and 6.9,2, find attached.a Special Report concerning Unit 2A Diesel Generator Invalid Failure on January 16, 1991, Very truly yours, W

M. S. Tuckman CRt./21/lcs Attachment xt:

Mr.-S. D. Ebneter Regional Administrator, Region 11 U. S. Nuclear Regulatory Commission 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 Mr. R. E. Martin Office of Nuclear Reactor Regulations 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 l

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SPECIAL REPORT CATAWBA NUCLEAR STATION DIESEL GENERATOR 2A INVALID FAILURE DURING OPERABILITY TESTING OF ENGINE An invalid failure (Start fi641) of Diesel Generator (D/G) 2A occurred on January 16, 1991. The failure occurred while closing the D/G breaker

-when synchronizing to the energized bus during the monthly operability

_ performance test, PT/2/A/4350/02A. There have been zero valid failures in tho' past 20 valid starts and two valid failures in the past 100 valid starts for D/G 2A.

The test surveillance interval-is once per thirty-one days for both Diesel Generators, which is-in compliance with Technical Specification 4.8.1.1.2 Table 4.8-1.

The' operator performing this test was doing so as part of training to increase awareness of the potential for reverse power relay actuations.

Af ter ' discussions with the operator involved, it was concluded that this incident was caused when theioperator hesitated once the breator was closed, instead of immediately increasing load-on the D/G., This

. hesitation allowed the reverse power condition that existed when the breaker was closed to last long enough for the relay to time out,and trip the breaker open. This start attempt was classifled as an invalid failure, per Regulatory Guide 1.108, since the trip was due to operator error. Special reports were submitted in 1990 for similar situations on l

both Diesel-Generators.

In;an effort to reduce the potential;for-this type of invalid' failure, new operators will be requtred to perform the paralleling and loading operation as part of their training requirements.

1 The'D/G was available 'uring this period since the reverse power relay j

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trip and associated synchronizing circuitry are bypassed during an emergency start.

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