ML20212E944
| ML20212E944 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 02/27/1987 |
| From: | Lenart R DETROIT EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NP870112, NUDOCS 8703040584 | |
| Download: ML20212E944 (4) | |
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1r g,n, Reg. Guide 1.108 February 27, 1987 NP870ll2 U. S. Nuclear Regulatory Commission Attention:
Document Control Desk washington, D. C.
20555 l
Reference:
Fermi 2 NRC Docket No. 50-341 i
Facility Operating License No. NPF-43
Subject:
Emeroency Diesel Generator Start Failure Please find attached our report on one start failure of Emergency Diesel Generator (EDG) 14 which occurred on January 30, 1987.
This report is submitted to you in accordance with Fermi 2 Technical Specifications 4.8.1.1.3 and 6.9.2.
l If you have any questions regarding this report, please contact Mr. Lewis Eregni at (313) Sn6-5313.
Sincerely, L Rs L, R. S. Lenart Plant Manager l
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W. G. Rogers J. J. Stefano USNRC Region III go l o
8703040584 B70227 PDR ADOCK 05000341 3
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U.-S. Nuclear Regulatory Commission-February 27; 1987
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NP870ll2-
.Page 2 t-ENCLOSURE l'
. Emergency Diesel Generator Start Failure-L 1..
Emeroencv Diesel Generator Involvedt Emergency-Diesel Generator-(EDG) 14 2.
Identification of Failure r Failure-Date:
January 30, 1987, 0900-hours j
. Description-of. Events.
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This is the first start failure of EDG 14-that occurred during a valid test following the: issuance of the Fermi 2' operating? license. : There have been four. start H
failures.during invalid tests since the operating license was' issued.
At the~ time of this~ start failure there have been 29 valid tests starts since the operating license was issued.
The January 30, 1987.
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start failure is considered a failure in valid test
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under - section c.2.e (6) of NRC Regulatory' Guide 1.108 i
because the engine start was-terminated intentionally
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because of an abnormal condition that may haveLresulted in diesel generator failure.. This abnormal condition was the f ailure of the EDG service water pump to automatically start; requiring operator intervention.
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Cause of Failurer on January 30, 1987, EDG 14 was being started to-perform a " slow" start surveillance test which is required on a monthly basis.
During a " slow" start, the engine is started and the speed is gradually increased to 940 rpm j
before loading.
While the engine was accelerating during this test, a chattering noise was heard from the relay cabinet located in the local engine control room.
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At the same time, the operator at-the local control panel noticed that the EDG service water pump and the selected fuel oil transfer pump had not automatically i
started as expected.
The operator manually started the pumps from the local control panel.
When the engine had 1
accelerated to 940 rpm, the tachometer on the local
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engine gauge panel read approximately 300 rpm and the reading waivered.
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LU.fS." Nuclear Regulatory Commission
' February"27, 1987'
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Page:3
- After contacting the Nuclear Shift Supervisor, the' operatorjstopped'the engine. 'During the test, the Lexciter7 remained in bypass and the engine was not loaded.
Included -inc the starting logic for the engine is a Laigna1' generator which is driven by.one of the engine
- camshafts.
The signal generator provides a speed dependant signal tolthe tachometer relay. 'The tachometer relay contains a 250 rpm (low speed)' relay
. and a 810' rpm.(normal 1 speed) -relay and provides a signal tofthe local tachometer.
The 250 rpm relay-performs numerous. functions including starting both the EDG service water pump and the selected fuel oil transfer pump.
Based on these f acts,.the investigation of this incident concentrated on the tachometer relay and the signal generator.
The tachometer. relay was checked for calibration with a
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simulated input-signal.
It determined that the tachometer relay output to the tachometer was approximately 144-low but both the 250 rpm and 810 rpm relays were within tolerance.
The signal generator was checked for proper: operation and was found to be r
functioning correctly.
The entire start string was then t1
. functionally checked by using a simulation of the engine
- accelerating.
The local tachometer read correctly and all the relays functioned with no chattering.
A *no credit" troubleshooting _ start attempt initially failed
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because the signal generator drive was not engaged in J
the camshaf t. ~ The camshaf t had been disengaged during the start string check.
After the signal generator was reinstalled correctly, the EDG 14 was started and successfully completed a one hour no credit troubleshooting run.
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Corrective MeagalIAA fAktDi The output relay was adjusted back into tolerance.
All of the relays that were suspected of chattering were visually inspected and the terminations were verified to be tight.
After various checks had been performed, the EDG 14 was started and successfully completed the surveillance test.
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- U. S. Nuclear Regulatory. Commission February 27, 1987 NP870ll2 Page 4 No root cause for the relay chattering that occurred during the January 30, 1987 start was found during the investigation.
Maintenance and operational records and NPRDS records of other plants for the-EDGs were reviewed to determine if-there has'been'any history of tachometer relay problems.
No adverse trend existed.
New tachometer relays have been ordered and received.
One of these new relays will be calibrated and. installed in EDG 14.
The existing EDG 14 tachometer relay will then be disassembled to attempt to determine root cause and if any additional corrective action is required.-
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Lenath of Time ElX3 Unit Unavailable:
EDG 14 was out of service 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> to investigate the relay chattering.
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Current Surveillance Test In ter.valJ The current surveillance test interval is once per 31 days.
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yetification of Conformance of Test-Intervair Because the number of valid test start failures of EDG 14 is equal to 1 in the last 20,-the required test frequency as stated in. Fermi 2 Technical Specification Table 4.8.1.1.2-1 is at least once per 31 days.
Therefore the current surveillance tent interval is in conformance with Fermi 2 Technical Specification Table 4.8.1.1.2-2.
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