ML20065A376
| ML20065A376 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 03/29/1994 |
| From: | Pecker D ENTERGY OPERATIONS, INC. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| SR-94-001, SR-94-1, W3F1-94-0037, W3F1-94-37, NUDOCS 9403310136 | |
| Download: ML20065A376 (3) | |
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Enter V -
Entergy Operations, Inc.
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J-PO. Box 9 Operations u=m um Tol 504-4G03120 D. F. Packer G.*cd Mxugrr Pi in! Opentt em Ws no r:13 u
W3F1-94-0037 A4.05 QA March 29, 1994 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C.
20555
Subject:
Waterford 3 SES Docket No. 50-382 License No. NPF-38 Reporting of Special Report Gentlemen:
Attached is Special Report Number SR-94-001-00 for Waterford Steam Electric Station Unit 3.
This Special. Report is submitted in accordance with Technical' Specifications 4.8.1.1.3 and 6.9.2 and USNRC Regulatory Guide 1.108.
Very truly yours,
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D.F. Packer General Manager - Plant Operations DFP/TWG/tjs Attachment cc:.
J.L. M11hoan, NRC Region IV.'
1 G.L. Florreich J.T. Wheelock - INP0 Records Center R.B.;McGehee N.S. Reynolds NRC Resident Inspectors Office Administrator - LRPD-
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SPECIAL REPORT SR-94-001 REPORTABLE OCCURRENCE Emergency Diesel Generator (EDG) 'A' experienced nonvalid failures on two occasions. The first failure occurred during a nonvalid test on February 28, 1994; the second during a valid test on March 2, 1994. An additional invalid failure occurred during the troubleshooting process.
EVENT DESCRIPTION At 1318 on February 28, 1994, Emergency Diesel Generator (EDG) 'A' was started in accordance with Operating Procedure OP-903-068, " Emergency Diesel Generator and Subgroup Relay Operability Verification," to demonstrate the operability of the diesel in accordance with Technical Specification (TS) 4.8.1.1.2.
Approximately 37 minutes after reaching full load, EDG load began to oscillate between 3.8 and 4.4 MW. The EDG was subsequently unloaded, secured, and declared inoperable at 1424.
At 1605 on February 28th, operators attempted to start EDG 'A' using the mechanical governor (electronic governor disconnected) as a first step in localizing the problem. This start was unsuccessful as the EDG tripped on overspeed. A new mechanical governor was installed and tested satisfactorily.
However, with the electronic governor back.in service, the load oscillations were still present, indicating that any remaining fault was in the electronic and not the mechanical governor.
Subsequent troubleshooting identified faulty contacts in a relay associated with the electronic governor's ' droop' (test) mode of operation. After replacing the relay, EDG 'A' was started at 1237 on March 2,1994 to verify correction of the problem and demonstrate compliance with TS 4.8.1.1.2.
In the process of paralleling to the bus, the EDG tripped on reverse power.
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I At 1439 on March 2, 1994, EDG 'A' was restarted to perform the TS j
surveillance. The test was completed satisfactorily and the diesel was declared operable at 1740.
CAUSAL FACTORS Investigation to date revealed that the load oscillations were caused by j
the failure of a set of contacts on a relay associated with the electronic i
governor's ' droop' mode of operation. These contacts are utilized when-the EDG is paralleled to the bus for loading after an emergency mode start. They are not used during emergency ('isochronous') operation and thus would not have prevented the EDG from performing its safety function.
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In0estigation of the overspeed and reverse power trips will continue and corrective actions will be taken as appropriate.
CORRECTIVE MEASURES The mechanical governor and the faulty relay were replaced; the mechanical governor will be sent to an off-site facility for additional testing.
SAFETY SIGNIFICANCE An engineering evaluation of EDG governor circuitry determined that the l
faulty relay contacts would not have affected EDG operation in the emergency mode.
Similarly, neither the overspeed nor the reverse power j
trip events would have affected emergency mode operation. As a result, theso events did not compromise the health and safety of the public or plant personnel.
In accordance with USNRC Regulatory Guide 1.108, the current surveillance I
test interval for EDG ' A' is 31 days.
EDG ' A' was unavailable for 51.3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />.
SIMILAR EVENTS l
No previous similar events vere identified.
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