ML20086A166

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Special Rept:On 910415,two Invalid Failures of Diesel Generator 1A Occurred During Refueling Outage.Caused by Failed Cooper Industries/Enterprise Model 1A-6147 Logic Board.Logic Board Will Be Replaced
ML20086A166
Person / Time
Site: Catawba Duke Energy icon.png
Issue date: 11/07/1991
From: Tuckman M
DUKE POWER CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9111180276
Download: ML20086A166 (2)


Text

, Duke frurt Company piQNi 3m'1 Cutairba helvor Stalitm l'O But 2.56 Clacer. SC 29710 DUKEPOWER November 7,1991 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555

Subject:

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

l Invalid Failure of Diesel Generator 1A L

l Pursuant to Technical Specification 4.8.1.1.3 and 6.9.2, find attached a Special Report concerning the two Unit 1 Diesel Generator A (D/G 1 A) invalid failures that occurred on April 15, 1991.

Very truly yours,

(--

f1.).kaCO m M.S. Tuckman CRL/DG1 A117.91 -

Attachment xc: F. D. Ebneter Regional Administrator, Region 11 W. T. Orders Senior Resident Inspector R. E. Martin, ONRR l

l 911116027o 911197 gl PDR f4 LOCK 07_,000413 ff '] g7 g

PDR

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SPECIAL REPORT CATAWBA NUCLEAll STATION DIESEL GENERATOR 1A INVALID FAILURE DUE TO LOGIC BOARD FAILURE Two invalid failures of Diesel Generator (D/G) 1 A occurred on April 15, 1991 during 1EOC5 refueling outage. The starts were originally classified as invalid tests. Further evaluation resulting from a Self Initiated Team Audit (SITA) revealed that these abould have been classified as invalid failures, thus prompting the issuance of this special report.

. At the time of these failures, Unit I was in Mode 5 during refueling outage number 5 (IEOC5). Catawba Technical Specifications require that only one D/G be operable in Mode 5.

Since the IB D/G was operable, the 1 A D/G was not required during this time. ~ acrefore, there is no unavailat ility time associated with these invalid failures. D/G 1 A was on a monthly test frequency prior to the l

engine inspection being performed. There have been 0 valid failures in the last 20 valid tests and 0 valid failures in the last 100 valid test on D/G 1 A. D/G 1 A remains on a monthly operability test schedule per Technical Specification

4. 8.1.1. 2 Table 4. 8-1.

After the hispection of D/G 1 A was completed, the normal schedule of break-in runs was started to ensure the complete reliability of the engine prior to its being returned to service. During start attempt # 861, the engine tripped 60 seconds into the run. Instrumentation and Electrical (IAE) personnel were called to investigate. The IAE personnel requested that the engine be run again so that certain pressures in the pneur itic control system could be observed to determine the cause of the trip. The engine was started once more (start attempt # 862) and again the engine tripped after 60 seconds.

This time, however, it was no.ed that the pneumatic shutdown logic board was not oparating properly. The logic board was replace per Work Order # 91028'107-01.

The engine was then successfully run and the remainder of the break-in runs were completed.

The failed logic board is a Cooper Industries / Enterprise Model Number 1 A-6147.

The exact cause of this board failure could not be determined. A work request search revealed that thero was not a significant history of failures associated with this particular part. The non-emergency pneumatic control system will be replaced with an electrical system during IEOC6 and 2EOC5 outages per NSM #'s CN-11149 and CN-20528, respectively.

The shutdown logic board will be replaced as a part of this modification. Since this failure occurred, no other problems have occurred with this particular part on any of the D/G's, f