ML20151U677

PNO-77-085:on 770516,TPS Unit 3 Reactor Tripped When RPS Received Signal That 3C Pump Had Tripped.Low Grid Voltage Caused Fossil Units to Trip.Slp Unit 1 Also Affected by Voltage Loss.Power Restored to Sys Grid from Fossil Units

ML20151U677
Person / Time
Site:	Saint Lucie, Turkey Point
Issue date:	05/16/1977
From:	Blackwood E, Sniezek J, Thornburg H NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
To:
References
PNO-77-085, PNO-77-85, NUDOCS 9809110119
Download: ML20151U677 (1)

Text

6 m ;. a n- ----mm.,-~_.. _ PRELIM

_ _INARY N..OTIFICATION

,__ N% 4  ;

1 , 16, 1977 "

PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-77-85 k7CMt" ~

This preliminary notification constitutes EARLY notice of an event of POSSIBLE safety or public interest significance. The information presented 1a as initially received without verification or evaluati_on and is basically 621 that is known by IE staff on this date.

Facility: Florida Power and Light Company Turkey Point Unit No. 3, 4 and St. Lucie Unit No. 1 (Florida)

Subject:

FP&L SYSTEM BLACK 0UT -

~

Turkey Point Unit No. 3 reactor tripped from 100% of rated power at 10:09 a.m. on 5/16/77 when the reactor protection system received a spurious signal that the 3C Reactor Coolant System Pump had tripped.

At 10:24 a.m. low voltage,on the grid .

caused Turkey Point fossil Units 1 and 2 to trip and a loss of off site power occurred. The diesels started and cooldown of the reactor was in progress using emergency equipment. The loss of voltage also caused a voltage oscillation at St. Lucie Unit No. I which was manually tripped to prevent equipment damage. Diesel generators were reported to be operating normally at St. Lucie and Turkey Point. Turkey Point Unit No. 4 had been shutdown for refueling prior to the blackout.

The blackout is reported to include most of the FP&L system. Turkey Point Unit No. 3 trip was caused by a reactor protection relay coil f ailing open and inputting a reactor trip signal.

i ,

There have been no other equipment or system failures at the St. Lucie .

%Eb or Turkey Point facilities reported. No release of radioactivity was

. experienced.

. I Power has been restored to the System grid from Turkey Point fossil Units 1 and 2. Turkey Point Unit No. 3 and St. Lucie Unit No. I are preparing to resume operation.

Media interest has occurred. NRC does not plan to issue a press release.

s-Region II received notification of this occurrence by telephone at 12:30 p.m. on 5/16/77. Region II inspectors are enroute to both the St. Lucie _,

and Turkey Point sites.

Contact:

EBlackwood, IE x27451 JSniezek, IE x27451 HThornburg, IE x27265 Distribution: Transmitted H St bb N3Y Chairman Rowden C. C. Kammerer, CA G. F. Murphy, JCAE Commissioner Kennedy S. J. Chilk, SECY H. H. Whiteside, SCNR

, Commissioner Gilinsky q g 3, H. R. Myers, HCEE, Transmitted: MNBB N P Bldg [.* 2. Y SS Bldg f/ L 5 L. V. Gossick, EDO E. G. Case, NRR C. V. Smith, NMSS S. H. Hanauer, EDO J. A. Harris, PA 6

, /

W. G. Mcdonald, MIPC Luge (MAIL) E. Volgenau, IE l I

R. G. Ryan, OSP T. J. McTiernan, OIA Region ((((j>/hh l H. K. Shapar ELD J! T 7 I PRELIMINARY NOTIFICATION l 9809110119 770516 PDR I&E - 1 PNO-77-005 PDR ,

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