ML17348A411

LER 90-013-00:on 900615,reactor Trip Occurred When Operator Raised Power Above 10% W/Turbine in Tripped Condition.Caused by Personnel Error.Event Reviewed W/Operations Personnel & Operator Training in Selfchecking initiated.W/900713 Ltr

ML17348A411
Person / Time
Site:	Turkey Point
Issue date:	07/13/1990
From:	Harris K, Dawn Powell FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
L-90-254, LER-90-013, LER-90-13, NUDOCS 9007230140
Download: ML17348A411 (8)

Text

ACCELERATED SYSTEM DISTRIBUTION DEMONSTRATION REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9007230140 DOC.DATE: 90/07/13 NOTARIZED: NO DOCKET FACIL:50-250 Turkey Point Plant, Unit 3, Florida Power and Light C 05000250 AUTH. NAME. AUTHOR AFFILIATION POWELL,D.R. Florida Power & Light Co.

HARRIS,K.N. Florida Power & Light Co.

RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 90-013-00:on 900615,reactor trip due to operator-error.

W/9 ltr.

DISTRIBUTION CODE: IE22T COPIES RECEIVED LTR ENCL SIZE:

TITLE: 50.73/50.9 Licensee Event Report (LER), ncident 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 EDISON,G 1 1 INTERNAL: ACNW 2 2 AEOD/DOA 1 1 AEOD/DSP/TPAB 1 1 AEOD/ROAB/DSP 2 2 NRR/DET/ECMB 9H 1 1 NRR/DET/EMEB9H3 1 1 NRR/DLPQ/LHFB11 1 1 NRR/DLPQ/LPEB10 1 1 NRR/DOEA/OEAB11 1 1 NRR/DREP/PRPB11 2 2 NRR/DST/SELB SD 1 1 NRR/DST/SICB 7E 1 1

/Z - BSDl 1 1 NRR/DST/SRXB SE 1 1 REG FF~ 02 1 1 RES/DSIR/EIB 1 1 GN2 FILE 01 ,1 1 EXTERNAL EG & G BRYCE g J ~ H 3 3 L ST LOBBY WARD 1 1 LPDR 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 IVASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOil 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 32 ENCL 32

P.O. ~14000, Juno Beach, FL 33408-0420 JUL 3 3 1990 L-90-254 10 CFR 50.73 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555 Gentlemen:

I Re: Turkey Point Unit 3 Docket No. 50-250 Reportable Event: 90-13 Date of Event: June 15, 1990 Reactor Tri Due To Operator Error The attached Licensee Fvent Report is being submitted pursuant to the requirements of 10 CFR 50.73 to provide notification of the subject event.

Very truly yours, I

K. N.~ Harris Vice President Turkey Point Plant Nuclear KNH/DPS/dps attachment cc: Stewart D. Ebneter, Regional Administrator, Region II, USNRC Senior Resident Inspector, USNRC, Turkey Point Plant QOO72;.'O<4O 5'OOi13 F DR @DOCS: O.'OO2,'.~O I

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~~ m >n o s o io io I 2!5,:0 9i0 0 1 3 0 0 0) 2o~0 l4 I. EVENT DESCRIPTION On June 15, 1990, at 1012 EDT, with Units 3,and 4 -in Mode 1 (Power Operation) at 100 percent power, Unit 3 experienced a high conductivity alarm (steam generator/main condenser) . The alarm was determined to be caused by a condenser tube leak. A power reduction was initiated in order to repair the leaking condenser tube. At 1137 EDT, with the unit at 25 percent power, due to the high-chloride contamination of the steam gene ators, a decision was made to take the unit to Mode 2 (Start-up) . When the reactor (AA) (RCT) was below 10 percent power, the turbine (TA) (TRB) was manually tripped.

On June 15, 1990, at 1203 EDT, with Unit 3 in Mode 1 (Power Operation) at 10 percent power and Unit 4 in Mode 1 at 100 percent power, Unit 3 experienced a reactor trip when the Operator raised power above 10 percent with the turbine in a tripped condition.

Reactor power above 10 percent automatically resets the P-10 reactor trip permissive (reactor power greater than 10 percent) which in conjunction with a turbine trip provides.a reactor trip.

The unit was stabilized in Mode 3 (Hot Standby) in accordance with approved plant procedures. On June 15, 1990, at 1253 EDT, the NRC was notified of this event in accordance with 10 CFR 50.72 (b) (2) (ii) .

ZI. EVENT CAUSE This event was caused by cognitive personnel error in that a licensed operator while attempting to correct a low reactor coolant system (RCS) (AB) temperature by pulling rods (AA) (ROD), failed to consider plant parameters with respect to reactor trip set points.

Inadequate command control by the Control Room Supervison .

contributed to the error.

The low RCS temperature arose from a combination of boration and rod insertion to reduce reactor power and a slightly higher than normal rate of feedwater addition to the steam generators. The combination of these conditions caused the RCS average temperature to drop below 543 degrees Fahrenheit. Low RCS average temperature is a concern because an average RCS temperature of 543 degrees.

Fahrenheit or less makes up one of the inputs to the "High Steam Flow / Low T average Safety Injection" and in addition low RCS average temperature causes reactor coolant shrinkage which can cause low pressurizer level.

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N Turkey Point Unit 3 o 5 o)ohio l2! 5i0 0 0 TEXT I/ meme a ~'Q 9(0 1 3 0 OI3o~ 0<4 NIOC IIN1N lib Also contributing to this event was a lack of adequate communications between the different operators involved in this event; in that the turbine was tripped prior to verifying that the reactor and steam generators were in a stable condition below 10 percent eactor power.

III. EVENT SAFETY ANALYSIS A reactor trip due to a turbine trip at power greater than 10 percent (P-10,permissive logic) is a previously analyzed event. As a result of these analyses, plant procedures are developed to provide operator guidance in responding to these transient conditions and to assure that the plant is stabilized in a safe condition in accordance with the plant Technical Specifications..

The unit was stabilized in Mode 3 in accordance with these approved plant procedures. All safety related equipment operated per design.

IV. CORRECTIVE ACTIONS A. Immediate Corrective Actions:

The unit was stabilized in Mode 3 in accordance with approved plant procedures. All safety related equipment operated per design.

Corrective Actions to Prevent Recurrence:

This event will be reviewed with all applicable Operations personnel to increase awareness of the potential for undesirable results due to a failure to mentally review the consequences of actions being performed. In addition', the necessity of adequate communications between the different operators and the Plant Supervisor Nuclear is being stressed during this review since inadequate communications was determined to have 'been a significant contributing cause of this event.

This review is scheduled to be completed by August 31, 1990.

2. Operator training in self-checking was initiated as a result of an Event Response Team (ERT) recommendation following a May 26, 1990, manual reactor trip due to "Operator Error." This training is scheduled to be completed by August 1, 1990. Operators are being trained to take time to evaluate the consequences of their actions before operating equipment or control devices.

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3. In addition, a new night order was issued to the Control Room Supervisors, covering significant operating evolutions such as unit startups, shutdowns, turbine valve tests, etc. This night order requires the Control Room Supervisor to establish himself as the command/control focus of the evolution and assure that evolution briefings are completed, that communications are accurate and adequate, and that evolutions are .smooth and controlled.

V. ADDITIONAL INFORMATION A. Similar Events LER 251-90-04-00 reported a May 26, 1990, manual reactor trip due to "Operator Error."

B. Equipment Failures None