ML17348A905

LER 91-001-00:on 910313,startup Transformer Deenergized Due to Const Activities Taking Place to Modify Control Room Control Board.Event Response Team Appointed to Complete investigation.W/910314 Ltr

ML17348A905
Person / Time
Site:	Turkey Point
Issue date:	03/14/1991
From:	Plunkett T, Dawn Powell FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
L-91-083, L-91-83, LER-91-001-01, LER-91-1-1, NUDOCS 9103200136
Download: ML17348A905 (10)

Text

ACCELERATED . DISTRIBUTION DEMONSTRATION SYSTEM 0

REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9103200136 DOC.DATE: 91/03/14 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. Florida= Power & Light Co.

RECIP-NAME RECIPIENT AFFILIATION

SUBJECT:

LER 91-001-00:on. 910313 startup transformer deenergized due to construction activities taking .place to modify control room: control board. Event response team has been appointed to complete investigation.W/910314 ltr.

DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR ! ENCL SIZE:

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

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 AULUCK,,R 1 1 INTERNA'L: ACNW 2 2 1. 1 AEOD/DOA'EOD/ROAB/DSP AEOD/DS P/TPAB 1 1 2 2 NRR/DET/ECMB 9H, 1 ' NRR/DET/EMEB 1 1 NRR/DLPQ/LHFB11 1 1 7E'RR/DLPQ/LPEB10 1 1 NRR/DOEA/OEAB NRR/DST/SELB 8D NRR/DST SPLB8D1 1,1 1

1 1

1 NRR/DREP/PRPBll NRR/DST/SICB 7E.

NRR/DST/SRXB 8E 2

1 1

2 1

1 1 1 RES/DSIR/EIB 1 1 1 1 EXTERNAL: EG&G BRYCE,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 NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US'TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM P 1-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR'1 ENCL'1

Ik 0

.. Box 029100, Miami, FL, 33102-9100

@PL.

MAR 14 SS1 L-91-083 10 CFR 50.73 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555 Gentlemen:

Re: Turkey Point Unit 4 Docket No. 50-251 Reportable Event: 91-001-00 Date of Event: March 13, 1991 Unit 4 Startu Transformer De-ener ized The attached Licensee Event Report 251-91-001-00 is being provided in accordance with the requirements of 10 CFR 50..73.

Upon completion of the investigation of the event, a revision to this LER will be provided. The supplemental LER wi'll be provided by April 12, 1991.

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 C'DR 9103200136 9'10316 PDR ADOCK 0 0002. 1 an FPL Group company

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0 NRC Pore SSS U.S. NUCLtAR RKOVLATORY COCMOISSIOH (942 I APPROVED OMS NO. 2)050105 LICENSEE EVENT REPORT (LER) EXPIRES: 9/2)ISS DOCKET NVMSER LTI PACILITY NAMt lll Turke Point Unit 4 0 5 0 0 0 1 OF0 3 TITLE ICI Unit 4 Startup Transformer De-ener ized EVENT DATE (SI LKR NUAISKR (9) REPORT DATE ITI OTHER PACILITIKS INVOLVED ISI 5CQVKHTIAL llcvRKrrr OAY YEAR FACILITYHAMK5 DOCKET HVMSER(SI MOHTrr DA Y YEAR YEAR rrvM ~ '5 8 HVMOCR MOHTrr 0 5 0 0 0 0 3 13 9191 THIS REPORT Ill(E 0 0 1 0 0 0 3 149 1 IS SUSMITTED PURSUANT T 0 THE REQUIREMENTS op 10 cPR $ (Cnocc ono or mono ot toc rorrow rrcl (11 0 S 0 0 0 OPERATINO MODE ( ~ I 20.502(bl 20.50S(c) ~ 0.224)(2((NI TS.2 I(~ I Ill(r((I 20.COS( ~ l(1 l(i) SO.SS( ~ ) (Il ~ 0.224)(2)lr) TS.2 I)cl POTcE R LEYEL OTHER ISOOCrtP rrr AOI (root 20.400(c) 50.20(c) (2) ~ 0.224) (2) (Tc) 0 0 I Oorow orrd ro Tcct. HRC Pone 20.COK( ~ ) SO.T24l(2)III ~ O.724) (2 I ITIIII (A) WAI 20.COS(cl Ill(trl SO.TS(c) (2)(o) ~ O.TS4) 12)(TR()IS) 20.OOS ( ~ ) (I I (r) SO.2 24) (2) I II(I KO.224) 12) (5)

LICEICSEE CONTACT POR THIS LER l12)

HAME TELEPHONE HVMSER AREA COOK D:-R:-Powell, Superintendent of Licensing 305 24 -65 59 COMPLtTK ONE LINK POR KAON COMPONtNT PAILURK OESCRISED IN THIS RtPORT I IS)

MAHVPAC. EPORTAS(.E MAHUPAC EPORTASL CAUSE SYSTEM COMPONENT CAUSE SYSTEM COMPONENT TURKR TO HPROS TV RE R TO HPRDS

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? Tn' REPORT EXPECTED 114) 'UPPLEMENTAL MOHTII OAY YEAR EXPECTED SUSMISSION OATS I'ISI YEK (It ocr, comorctc ExptcTED Susotlss(DH DATE) NO 9 1 X

ASSTRACT ILrmrt to tcOO tooccc. I.A. ooororrmctorc trhccrr orrproooocc typowrrttoo orrcct Il~ I On March 13, 1991 at 1530 the Unit 4 startup transformer locked out, which caused the 4A 4160 volt bus to de-energize. The 4B 4160 volt bus was already out of service due to modifications being performed during the current outage. Two of four available black start diesel generators (not emergency diesels) were started and made available to provide power to the 4A bus. After an investigation to determine the cause of the lockout and a determination that the lockout was not due to a bus or transformer fault, power was restored to the bus at 1635. Preliminary investigations and interviews of personnel involved, leads us to believe that the cause was construction activities taking place to modify the control room control boards. Loss of power to the 4A bus resulted in the loss of'Spent Fuel Pool Cooling. Spent fuel pool cooling was restored at 1727. The pool temperature increased by approximately 3 degrees F. to 87 degrees F. during the time the cooling system was not in operation. An Unusual Event was declared at 1550 and terminated at 1727 when the spent fuel pool cooling was restored. State and NRC notifications were made as required.

NRC Sore SSS (902 I

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Point Unit 4 UAf'ease ~SI IITI EVENT DES RIPTION o s o o o.25 91 00 1 00 02 OF On March 13, 1991 at 1530 the output. breaker from the Unit '4 startup transformer to the 4A 4160 volt bus received a lock out signal. This resulted in .the isolation of the transformer and the 4A 4160 volt bus. The 4B 4160 volt bus was already out of service due to modifications being performed during the current outage. Two of four available black start diesel generators were started and made available to provide power to the 4A bus connected to the bus.

if required but were not The emergency diesel generators have been removed-from service during the Emergency Power System project. An investigation to determine the cause of the lockout and a determination that the lockout was not due to a bus or transformer fault was conducted. The Unit 4 startup transformer was re-energized at 1630 in accordance with Off-Normal Operating Procedure 4-ONOP-004, "Loss of Offsite Power." Power was restored to the 4A 4160 volt bus at 1635 from the.-startup transformer.

Loss of power to the 4A bus resulted in the loss of Spent Fuel Pool Cooling. Spent fuel pool cooling was restored at 1727. The pool temperature increased by approximately 3 degrees F. to 87 degrees F.

during the time the cooling system was not in operation.

An Unusual Event was declared at 1550 and terminated at 1727 when the spent fuel pool cooling was restored. State and NRC notifications were made as required.

II. EVENT CAUSE Preliminary investigations and interviews of personnel involved indicate that the cause was construction activities taking place to modify the control room control board.

III. EVENT .SAFETY ANALYSIS An occurrence of this type was considered during the planning for the Emergency Power Systems outage. 'Procedures were prepared for response to such an occurrence. The systems required to operate in the event of a loss of the capability to provide power from offsite sources worked as designed. Also a capability existed to tie the Unit 3 startup transformer to the 4A 4160 volt bus available to provide if needed. A truck mounted 400 Kw diesel was temporary power to provide cooling to the Spent Fuel Pool. In addition a diesel powered fire pump and non-vital screen wash pump are available to supply spent fuel pool cooling water. Also an alternate cooling system, in place for this outage could supply spent fuel pool cooling using non-vital power.

The rise in temperature of the spent fuel pool was less than predicted by the ana'lysis done for the safety. evaluation performed for the outage. The temperature of the spent fuel pool was monitored each half hour to ensure that the heat up rate was not greater than predicted.. Thus the health and safety of plant personnel and the general public was not compromised.

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~ otWtenV HHC Arte ~ 4 Ol IITI 0 5.0 0 0 2 5 9 10 0 10 0 0 3 OF 0 3 IV. CORRECTIVE ACTIONS A. Two of four available black start diesels power (non-safety related) were started and made available to supply to the 4160 volt bus.

B. Work in and around areas that could have contributed to the transformer lockout has been stopped. Management will release these areas for,work as the investigation progresses.

C. An Event Response Team has been appointed to complete the

. investigation and provide appropriate corrective actions.

V. ADDITIONAL INFORMATION A. A supplemental Licensee Event Report will be provided of the upon root completion of the investigation and determination cause.

~ SAC SQAiy 19491

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