ML20211P592

Ro:On 870123,start Failure Occurred During Testing of Emergency Diesel Generator 13.Caused by Personnel Failure to Reset Exciter Trip & Autostart Buttons After Setpoint Adjustment of Jacket Coolant Pressure Switch

ML20211P592
Person / Time
Site:	Fermi
Issue date:	02/20/1987
From:	Lenart R DETROIT EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NP870106, NUDOCS 8703020394
Download: ML20211P592 (4)

Text

_ _

27; %"

F erms-2 6400 N g=_.

Edison m=orthD,meHqhway - Re9. ouide 1.108 February 20, 1987 NP870106 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D. C. 20555

Reference:

Fermi 2 NRC Dochet No. 50-341 Facility Operating Licence No. NPF-43

Subject:

Emeraency Diesel Generator Start Failure Please find attached our report on one start failure of Emergency Diesel Generator (EDG) 13 which occurred on January 23, 1987. This report is submitted to you in accordance with Fermi 2 Technical Specifications 4.8.1.1.3 and 6.9.2.

If you have any questions regarding this report, please contact Mr. Lewis Bregni at (313) 586-5313.

Sincerely, l

,u Y R. S. Lenart Plant Manager ,

i cc W. G. Rogers l

J. J. Stefano USNRC Region III 00 87030203Y4 B70220 k DR ADOCK 05000341 PDR

7 U. S. Nuclear Regulatory Commission February.20, 1987 C NP870106 Page 2 ENCLOSURE 1 Emergency Diesel Generator Start Failure

1. Emeroency Diesel Generator ~ Involved:

Emergency Diesel Generator (EDG) 13

2. Identification of Failure:

Failure Date: January 23, 1987, 1319 hours0.0153 days <br />0.366 hours <br />0.00218 weeks <br />5.018795e-4 months <br /> Description of Event:

This is the second start failure of EDG 13 that occurred during what is considered an " invalid test" since the issuance of the' Fermi 2 operating license. At the time of this start f ailure there had been 109 valid test starts since the operating license was issued. The January 23, 1987 start failure is considered a failure in an " invalid test" under section C.2.e(2) of NRC Regulatory Guide 1.100 because operating error was involved in the start failure and the engine trip involved is bypassed in the emergency operating mode.

The number of start failures incurred during " valid tests" for EDG 13 since issuance of the operating license remains unchanged at zero.

3. Caure of Failure:

Occurrences that contributed to the cause of the start failure commenced on January 23, 1987. At 1050 hours0.0122 days <br />0.292 hours <br />0.00174 weeks <br />3.99525e-4 months <br />, I&C Personnel were performing a setpoint adjustment of the EDG 13 jacket coolant pressure switch (CPS) , which is a backup to the tachometer normal speed relay (810 RPM Relay) in the starting logic. This activity caused an " engine at normal speed" signal in the start logic, although the engine was not actually started. This resulted in the receipt of a jacket coolant trouble alarm, the exciter trip alarm and the EDG 13 not ready for auto atart alarm. Since the engine was not running, there existed a low jacket coolant. water pressure, which caused the jacket coolant trouble alarm. The jacket coolant trouble also caused a non-essential engine trip nignal that sealed in.

U. S. Nuclear Regulatory Commission February 20, 1987 NP870106 Page 3 l

At 1117 hours0.0129 days <br />0.31 hours <br />0.00185 weeks <br />4.250185e-4 months <br />, the I&C Technicians completed adjustment of-CPS and.c1 cared all alarms at the local panel by pushing the alarm reset button. Per system design,.the engine not ready ^ for autostart and the exciter trip alarms are'in the Control' Room (CR) but not at the local panel. Therefore, these alarms did not clear because the engine reset button was no't pushed. The engine reset button would have cleared the non-essential engine trip signals.

The Nuclear Supervising Operator (NSO) at the local EDG panel prepared to start the engine for the monthly start and load surveillance. The local panel alarms were all clear at thir Lime, but the engine was still tripped.

The not ready for auto start and the exciter trip alarms still existed in the CR.

The NSO at the local control panel then requested permission from the CR to start the engine.- The NSO was informed of the existence of the exciter trip alarm, however, he incorrectly reasoned that since he was going to place the exciter bypass switch in the bypass position, a reset was not necessary. The CRNSO also failed to notice the "EDG 13 not ready for auto start" alarm.

l The CRNSO then directed the NSO to start EDG 13. At

1319 hours0.0153 days <br />0.366 hours <br />0.00218 weeks <br />5.018795e-4 months <br />, the EDG 13 was started and tripped I approximately seven seconds later. Fuel was never admitted to the engine due to the pre-existing non-essential engine tr.ips.

[

The following errors cont-dbuted to this start failure:

l A. The Nuclear Assistant Shift Supervisor (NASS) d id not remove EDG 13 from service to perform I6C maintenance activities. Proper removal from service could have resulted in a proper return to standby service.

B. The NSO and the CRNSO failed to properly evaluate the significance of the exciter trip alarm.

The engine trip that existed during the entire sequence of events was a non-essential trip, which is bypassed if an emercency start signal is received. Hence, EDG 13 would have automatically started during an emergency, if required.

m U. S. Nuclear Regulatory Commission February 20, 1987 NP870106 Page 4-The engine tripped on the start attempt after seven seconds, per the start logic to conserve starting air.

Therefore, even after the start failure EDG 13 would have immediately started if an emergency had occurred.

Based on the above information and because the primary cause of_the start failure was operator error (not resetting the non-essential engine. trip), this is considered an " invalid test" start failure.

f.fter evaluating the cause of the start failure, the engine non-essential trip was reset, and EDG 13 was started 40 minutes after the start failure. The EDG monthly surveillance was successfully completed.

4. Corrective !!easures Taken1 The following corrective actions will be taken to prevent recurrence:

A. Provide required reading'for operations personnel regarding the event.

B. NASS will be counseled on philosophy of release of equipment for maintenance.

C. The !!aintenance Engineer will notify all maintenance personnel regarding the procedural requirement relative to operation of equipment by non-operations personnel.

5. Length of_ Time EDG Unit Unavailablet EDG 13 was available for Emergency Starts at all times during this start failure and subsequent investigation.

6. Current Surveillance Test Interval:

The current surveillance test interval remains unchanged at 31 days.

7. Ectifiqat; ion of Conformance of Tect Interval:

necause this start f ailure is considered an " invalid test" start failure as defined in Regulatory Guide 1.108 the EDG. surveillance test interval is not affected. The current surveillance test interval is in conformance with Regulatory Guide 1.108 and with Fermi 2 Technical Specification Table 4.8.1.1.2-2.