PNO-III-99-002, on 990106,partial Loss of Offsite Power Occurred.Power Lost to Rhrs,Normal Shutdown Cooling Sys & in Svc at Time of Event.Plant Three EDGs Started Automatically & Provided Power to Safety Sys.Power Restored to Rhrs Pump

PNO-III-99-002:on 990106,partial Loss of Offsite Power Occurred.Power Lost to Rhrs,Normal Shutdown Cooling Sys & in Svc at Time of Event.Plant Three EDGs Started Automatically & Provided Power to Safety Sys.Power Restored to Rhrs Pump

ML20206P444
Person / Time
Site:	Clinton
Issue date:	01/08/1999
From:	Dupont S, Kozak T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
References
PNO-III-99-002, PNO-III-99-2, NUDOCS 9901110405
Download: ML20206P444 (1)

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?[ , 9 - January 8. 1999 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNO-III-99-002

- This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or p0blic interest significance. The information is as initially received without verification or evaluation,~ and is basically 'all that is known by Region III staff (Lisle, Illinois) on.this date. ,

Facility Licensee Emergency Classification Illinois Power Co. X Notification of Unusual Event ,

Clinton 1 Alert Clinton. Illinois Site Area Emergency Dockets: 50-461 General Emergency ,

Not Applicable-l

Subject:

PARTIAL LOSS OF 0FFSliE POWER l At 1:45 p.m. on January 6.1999.there was a loss nf the 138-kV electrical l line which supplies power to the emergency reserve auxiliary transformer  !

(ERAT). This transformer was supplying power to the plant's '

safety-related equipment.

The ERAT is the backup transformer for the reserve auxiliary transformer, '

which 3rovides-incoming power to the plant's safety-related equipment l throug1 the main switchyard. The reserve auxiliary transformer was taken out of. service on' January 6, 1999, in preparation for degraded voltage modification work. The licensee declared an Unusual Event under its emergency plan. i

' Power was lost to the residual heat removal system, which is the normal shutdown. cooling system and was in service at the time of the event.

Forced cooling water flow through the core was. maintained throughout the event since the reactor water cleanup system, an alternate means of shutdown cooling, remained in operation.

The plant's three emergency diesel generators started automatically and l provided power to the safety systems. l The balance-of-plant equipment did not lose power because it was connected to a different transformer. I Power was restored to a residual heat removal system pump at 4:00 p.m.

! The reserve auxiliary transformer was brought back to service and started supplying power to the plant safety systems at 11:06 p.m. and the Unusual Event emergency declaration was terminated, i The State of Illinois has been notified. The information in this

l. preliminary notification has been reviewed with licensee management, p

The licensee issued two press releases on the event.  ;

The licensee notified the NRC 03erations Center of this event at 3:26 p.m. (CT) on January 6, 1999. T11s information is current as of 5:00 p.m.

on January 7, 1999.

Contact:

Thomas Kozak Stevie Dupont l (630)829-9866 _

99o111o405 99010e y (630)829-9608 h L

. . .N I!U99-oo2 PDR b f .-

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