ML17222A733

Special Rept:On 890117 & 0203,emergency Diesel Generators 2A & 2B Failed.Diesel Trip Caused by Engine Design.Oil Splash Guards Will Be Installed on All Plant Diesels & Step Added to ESF Test Procedure

ML17222A733
Person / Time
Site:	Saint Lucie
Issue date:	03/20/1989
From:	Conway W FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
L-89-109, NUDOCS 8903310072
Download: ML17222A733 (4)

Text

R EGULATORY FORMATION DISTRIBUTION S "TEM (RIDS)

ACCESSION NBR:8903310072 DOC.DATE: 89/03/20 NOTARIZED: NO DOCKET FM~ IL:50-389 St. Lucie Plant, Unit 2, Florida Power & Light Co. 05000389 AUTH. NAME .

AUTHOR AFFILIATION CONWAYgW.F. Florida Power & Light Co.

RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Special rept:on 890117 & 0203,emergency diesel generators 2A & 2B failed. R DISTRIBUTION CODE: IE22D COPIES RECEIVED:LTR J ENCL

+ SIZE: 3 TITLE: 50.73 Licensee Event Report (LER), Incident Rpt, etc.

f NOTES:

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-2 LA 1 1 PD2-2 PD 1 1 NORRISiJ 1 1 INTERNAL: ACRS MICHELSON 1 1 'ACRS MOELLER ACRS WYLIE 1 1 AEOD/DOA AEOD/DSP/TPAB 1 1 AEOD/ROAB/DSP DEDRO 1 1 IRM/DCTS/DAB NRR/DEST/ADE 8H 1 1 NRR/DEST/ADS 7E NRR/DEST/CEB 8H 1 1 NRR/DEST/ESB 8D NRR/DEST/ICSB 7 1 1 NRR/DEST/MEB 9H NRR/DEST/MTB 9H 1 1 NRR/DEST/PSB 8D NRR/DEST/RSB 8E 1 1 NRR/DEST/SGB 8D NRR/DLPQ/HFB 10 NRR/DOEA/EAB 11 NRR DRLS SIB 9A 1,

1 1

1 1

1 NRR/DLPQ/QAB NRR/DREP/RPB NUDOCS-ABSTRACT 10 10 G IL 02 1 1 RES/DSIR/EIB RES DSR/PRAB 1 1 RGN2 FILE 01 EXTERNAL 'G&G WILLIAMS S E 4 4 FORD BLDG HOYiA H ST LOBBY WARD 1 1 LPDR NRC PDR 1 1 NSIC MAYS,G NSIC MURPHYgG A ~ 1 1 A

D D

NCTE IO ALL "RIDS" RECIPIENTS:

S PIZASE HELP US R) REHJCB WLSHr! CGÃI'ACT 'IHE IXXXMEÃI'XWZROLDESK BQCN Pl-37 (EXT. 20079) KO ELBKKIXB KX3R NAME EBCH DISTORTION I'M P3R DOCtIMENZS YOU DOH~T NEZDt TOTAL NUMBER OF COPIES REQUIRED: LTTR 44 ENCL 43

P.O. Bo~, l000, Juno Beach, FL 33408-0420

/BARGED 2 0 1989 L-89-109 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555 Gentlemen:

Re: St. Lucie Unit 2 Docket No. 50-389 Date of Event: January 17, 1989 and February 3, 1989 S ecial Re ort on Diesel Generator Failures The attached Special Report is being transmitted pursuant to the requirements of Technical Specification 4.8.1.1;3 to provide notification of 2A and 2B Emergency Diesel Generator failures.

Very truly yours, W. . Con Sensor Vi President Nuclear WFC/JRH/cm Attachment cc: Stewart D. Ebneter, Regional Administrator, Region Senior Resident Inspector, USNRC, St. Lucie Plant II, USNRC SS'0331 pp72 890320 PDR ADQCK 05000389 8 PNU JRHSRDGF an FPL Gyoup company,

SPECIAL REPORT DIESEL GENERATOR FAILURES 2B DIESEL GENERATOR FAILURE:

In accordance with NRC Regulatory Guide 1.108, Section C.2.e, this event is considered a non-valid diesel generator failure since it was caused by a "malfunction of equipment that is not operative in the emergency operating mode". As per Unit 2 Technical Specification 4.8.1.1.3, the event is being submitted as a Special Report.

At 0600 on January 17, 1989, the 2B diesel was taken out of service for routine maintenance. In order to repack the soakback oil pumps, the soakback oil system and standby immersion oil heaters were taken out of service. At midnight on'anuary 17, the soakback oil system was placed back in service. In accordance with the engine manual, the engine oil was verified to be above 85'F after about one hour of soakback syst: em operation. The engine was fast started from the control room for a post-maintenance surveillance run at 0158 on January 17, but tripped almost immediately on high crankcase pressure on the 2B2 (12 CYL) engine. Following the trip, the crankcase pressure trip device on 2B2 diesel was found tripped and was successfully reset. The lube oil was then heated and the engine was fast started again. Another post-maintenance surveillance run was performed with satisfactory results. The 2B diesel was then returned to standby service.

The cause of the diesel trip was in the engine design. Under

'certain conditions (i.e., fast starts and/or lower lube oil temperatures), the lube oil relief valve will relieve lube oil in close proximity to the crankcase pressure detector, causing a crankcase overpressure trip. The high crankcase pressure trip is not operative when the diesel generator is in the emergency operating mode, therefore, this is considered a non-valid failure.

Planned corrective action is to install oil splash guards on all St. Lucie plant diesels, as was already done on the 2A diesel.

Also, since the Technical Specification as revised by Amendment No.

39 now allow idle starts, procedure changes are being prepared in order to perform idle diesel engine starts when the soakback oil system has been out of service for extended periods.

JRHSRDGF

2A DIESEL GENERATOR FAILURE:

In accordance with NRC Regulatory Guide 1.108, Section C.2.e, this event is considered a non-valid diesel generator failure, since the failure was not attributable to the defined diesel generator unit design. As per Unit 2 Technical Specification 4.8.1.1.3, this event is being submitted as a Special Report.

At 1707 on February 3, 1989, a loss of off-site power was simulated in conjunction with the testing of engineered safety features on Unit 2. This condition requires the diesel generators to auto start and energize their respective safety-related loads.

With the loss of off-site power, the 2A and 2B diesels started and sequenced loads as designed. However, the strip chart recorder which was being used locally in the diesel generator building to monitor the diesel generator's voltage and frequency was discovered by Electrical Maintenance personnel to be indicating 0 volts and 0 hertz frequency. It was discovered that two test leads D/G voltmeter to the chart recorder transduqer from the devices were disconnected. While re-landing these leads, a spark was observed.

The voltage regulatory/speed control potential transformer circuit were shorted, and a fuse was blown. The 2A diesel generator voltage control went high and the governor control went to about 58HZ. The event was terminated by manually tripping the 2A diesel generator'locally, using the overspeed trip lever.

The two leads that had been disconnected from the chart recorder were required, by procedure, to be connected prior to the start of the test. The disconnected leads were not discovered until after the diesel start, primarily because the proper personnel were not on station in the diesel generator building when the test began.

Since personnel error was determined to be the cause of the event, this is considered a non-valid failure. Once the diesel generator was tripped, an inspection of the 2A diesel and "A" train equipment was performed to verify operability. A surveillance run was performed on the diesel generator with satisfactory results. The 2A diesel was then returned to standby service.

The major cause of the event was that all necessary personnel were not stationed prior to the test. Planned corrective action is to add a step in the engineered safety features test procedure that verifies all test personnel are stationed prior to the test.

JRHSRDGF