ML17348A911

LER 90-012-00:on 901221,emergency Diesel Generator Acceptance Test Stopped Due to Declining Coolant Water Level.Caused by Coolant Manifold.Defective Manifold Replaced by vendor.W/910315 Ltr

ML17348A911
Person / Time
Site:	Turkey Point
Issue date:	03/15/1991
From:	Plunkett T, Dawn Powell FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
L-91-059, L-91-59, LER-90-012-01, LER-90-12-1, NUDOCS 9103260074
Download: ML17348A911 (12)

Text

ACCELERATED D'RIBUTION DEMONS~TION SYSTEM

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',ACCESSION. NBR:9103260074 DOC.DATE:- 91/03/'15 NOTARIZED: NO .DOCKET

,FACIL:50-251 Turkey Point Plant, Unit 4, Florida Power and* Light...C 05000251

'AUTH. NAME AUTHOR AFFILIATION POWELL,D.R. Florida Power & Light Co.

. PLUNKETT,T.F.'lorida Power &,Light Co.

RECIP.NAME RECIPIENT AFFILIATION- R I

SUBJECT:

LER 90-012-00:on 901221,emergency diesel generator acceptance test. stopped due to declininq coolant water D level.Caused:by coolant manifold. Defective manifold replaced by vendor.W/910315 ltr.. S DISTRIBUTION CODE IE22T COPIES RECEIVED:LTR i ENCL ( ,STEE:

TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.

NOTES

, .RECIPIENT' COPIES RECIPIENT COPIES D ID CODE/NAME PD2-2

'LTTR ENCL ID CODE/NAME PD2-'2 PD LTTR ENCL LA 1 1 1 1 D AULUCK,R 1 1 INTERNAL: ACNW 2 2 AEOD/DOA 1 1 AEOD/DS P/TPAB 1 1 AEOD/ROAB/DS P 2 2' NRR/DET/ECMB 9H 1 1 NRR/DET/EMEB 7E 1

'8 NRR/DLPQ/LHFB11 1 1 NRR/DLPQ/LPEB10 1 1 NRR/DOEA/OEAB 1 1 NRR/DREP/PRPB11 2 2 NRR/DST/SELB 8D 1 1 NRR/DST/SICB 7E 1 1 NRR/DS D1 1 1 NRR/DST/SRXB 8E 1 1 REG RGN2 LE 0~

I'CE 01 1

1 1

1 RES/DSIR/EIB: 1 1 EXTERNAL EG&G BRYCE I J H 3 3 L ST LOBBY WARD 1 1 NRC PDR 1 1 NSIC MAYS,G 1 1 NSIC MURPHY,,G,.A 1 1 NUDOCS FULL TXT 1 1 D

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NOTE TO ALL 'lRIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE iVASTE! CONTACT THE DOCUMENT CONTROL DESK,,

ROOM Pl-37 (EXT. 20079) TO ELIMINATEYOUR'NAME FROM, DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T'NEED!

FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 31 ENCL 31

Ih P.O. Box 029100, Miami, FL, 33102-9]00 MAR 15 1991 L-91-059 10 CFR 50 73 U. S. Nuclear Regulatory Commi'ssion Attn: Document Control Desk .

Washington, D. C. 20555 Gentlemen:

Re: Turkey Point Unit 4 Docket No. 50-251 Reportable Event: 90-012-00 Date of Event: December 21, 1990 4 B Emergency Diesel Generator (DG) Water Leak Due to Manufacturing Defect Could Prevent DG From Performing Intended Safet Function The attached voluntary Licensee Event Report 251-90-012-00 is being provided for information purposes only following, the guidance provided by NUREG 1022, Supplement 1, Item 19.1.

Very truly yours, T. F. Plunkett Vice President Turkey, Point Nuclear

'TFP/DPS/ds enclosures cc: Stewart D. Ebneter, Regional Administrator, Region II, USNRC, Senior Resident Inspector, USNRC', Turkey Point Plant an FPL Grooo comoany 91032Ci0074 910325 gQci PDR ADOCI+ 0500025$

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o25 1>opO Turkey. Point 4 o 5 o o 4 B EMERGENCY DIESEL GENERATOR DG WATER LEAK DUE TO MANU U .'Ie"- OEFEC PREVENT DG FROM PERFORMIN GINTENDED SAFETY FUNCTION.

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LICEIQEE CONTACT SOh TH($ Lth lit>>

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EUSSLEMENTAL htSOhT EXSECTEO (14

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Y tt Illyee, o<<eseHe txstcyto SUEMIEEION CATE>> NO AMTIEAOTILkate ee IeSt Meeee, l.a. ~eeeoe<<y //heed Sees>><<Meee lyse<<et(Me soeel lltl This voluntary LER is being submitted following the guidance provided by NUREG 1022, Supplement 1, Item 19.1.

On December 21, 1990, at approximately 2300 EST, with both units defueled, the new 4B Emergency Diesel Generator (EDG) 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> acceptance test run was stopped due to declining coolant water level.

The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> test run was being performed as part of phase 1 FPL acceptance testing prior to turnover, scheduled for summer 1991, to the plant of two new EDGs that have been installed as part of the Emergency Power Systems Enhancement Project (EPS). A leak was located at the flange connection between the water inlet tube and the number 6 cylinder liner. When the water inlet pipe was removed, the 0-ring at this connection was found to be cut. The cause of the event was a coolant manifold which did not meet the tol'erances. This resulted in misalignment of the cooling manufacturerls,'imensional tube and damage to the 0-ring seal. Contributing to the misalignment was an assembly error by the manufacturer in that the manufacturer failed to follow the tech manual instructions 'for installation of the inlet cooling tube. The defective manifold was replaced by the vendor. The water inlet tubes and replacement 0-rings were installed by the vendor in accordance with the technical manual. The EDG 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> test was then completed satisfactorily.

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LICENSEE EVENT .REPORT'LER) TEXT CONTINUATION.'ACl Ll7Y TAHE DOCKET RUHBER 'LER HUHBER'AGE TURKEY POINT UNIT 4 91-012-00 HO.'5000251 02 OF,04 I. EVENT DESCRIPTION On. December 21, 1990., at approximately 2300'ST, with both units defueled, during a 72 .hour Emergency. Diesel Generator (EK)(EDG) acceptance test run, the test .was stopped after 27 hours3.125e-4 days <br />0.0075 hours <br />4.464286e-5 weeks <br />1.02735e-5 months <br /> due declining, coolant level in the new 4B EDG. The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> test runtowasa being performed as part of phase 1 FPL acceptance testing prior to turnover, scheduled for summer 1991, to the plant of two new EDGs that have been installed as part of the Emergency Power Systems Enhancement Proj'ect (EPS).

Investigation revealed that a leak had existed at the flange connection (EK)(CON) between the water inlet tube (EK),(TBG) and the number 6 cylinder liner (EK)(LNR). When the water inlet tube was removed, the O-.ring (EK)(SEAL) at -this connection was found to be cut.

II.. EVENT CAUSE a ~ Immediate Cause The loss of cooling water was the result of water leakage through a cut in the 0-ring seal between the water inlet tube and the number 6 cylinder liner. The cut in the 0-ring seal was caused during, installation of the water inl'et tube from the coolant manifold.

b. Root Cause

'The cause of this event was a. coolant manifold which was not manufactured in accordance with the General Motors Electromotive Division' dimensional,tolerances. These dimensional defects resulted in excessive handling of the water inlet tubes during alignment which resulted in the cut 0-r'ing.

c ~ Contributing Cause

, A possible contributing cause of the event was failure of the manufacturer, to follow Technical Manual instructions. on inlet cooling tube installation.. The Technical Manual furnished by Morrison-Knudsen Company is entitled: "Installation, Operating,,

Maintenance, and Parts Manual." Volume 1 of this manual contains sections supplied by, the diesel engine manufacturer, General Motors Electromotive 'Division, entitled '"Engine Maintenance.". Section 10 "Cooling System Piping," of volume 1 provides instructions on inlet cooling tube installation. The

0 LICENSEE EVENT REPORT (LER)',TEXT COHTXHUATZOH FACILITY NAME 'DOCKET ,NUMBER LER .NUMBER , 'AGE 'NO.

TURKEY -POINT'NIT 4 . 05000251 91-01'2-00 03 oF 04 failure to follow these installation .instructions resulted in deformation of the manifold and misal'ignment of, the fi'tted inlet water tube connection and damage to the 0-ring seal..

III. EVENT SAFETY ANALYSIS The Emergency Diesel Generators (EDGs) are necessary to ensure the capability to mitigate the. consequences of accidents. An engineeri;ng evaluation of this event by FPL engineering concluded that the loss of engine coolant,due:to the leakage described above would eventually, result i'n engine fai;lure due to engine overheating. In addition, the evaluation also. showed that even if sufficient makeup water were

.added to the system, water l'eakage i'nto the air 'box, would result in a loss of .power that could prevent the EDG from performi;ng intended safety .function., 0 it' The defect was discovered and corrected prior to the subject EDG being. turned over to the plant..

Pre-operational'ests had been developed'o locate problems similar to the leak. discussed above before the equipment being tested would be decl'ared operational and thus relied on to perform intended safety functions. Since,,this defect was discovered'nd repaired before the EDG completed final acceptance testing, the EDG. was never relied on to be available to provide. emergency power. Both units are defueled and EDGs, 4A and 4B are not required to support the, spent fuel pool or any other required, equipment. Thus- the health and safety of the publ'ic were not affected.

IV. CORRECTIVE ACTIONS

.Both manifolds and associated, hardware, includ'ing the cut O-ring, were removed and repl'aced by the~Morri.'sori-Knudsen 'Company, Inc. The water inlet tubes were installed in accordance with the Technical Manual noted above. The EDG acceptance tests were then continued.

No additional corrective actions are. deemed necessary by Florida Power '& Light to correct the discovered deficiencies.

The other new EDG on site, from the .same manufacturer, EDG 4A, was examined and found to not have the .deformed manifold, or the out of tolerance condition on the cool'ing. water manifold.

Morrison-Knudsen Company, Inc., has been notified of this event.

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LICENSEE'VENT RBPORT 'LBR) TEXT CONTINUATZON FACILITY NAHE DOCKET NUMBER . . LER NUHBER PAGE NO.

TURKEY POINT UNIT 4 05000251 91-.012-00 04 oF 04 V'DDZTZONAL ZNFORMATZON Similar LERs:

None

2. Vendor/Manufacturer:

Florida Power & Light Turkey Point EDGs 4A and 4B were assembled by Morrison-Knudsen Company, INC.

The diesel portion of the EDG was manufactured by the Electro-Motive Division of General Motors. The engine is a 20 cylinder, skid-mounted diesel. The engine model number is 20-645F4B The generator portion of the EDG was manufactured by NEI Peebles-Electric Products.

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