ML20206G977

PNO-OSP-88-018A:on 881118,Unit 1 Reactor Tripped.Caused by Electrical Ground in Main Generator.Licensee Initiated Outage Work Including Repair of Main Generator,Reactor Coolant Pump 3 Seal Package & Steam Dumps

ML20206G977
Person / Time
Site:	Sequoyah
Issue date:	11/21/1988
From:	Richardson S NRC OFFICE OF SPECIAL PROJECTS
To:
References
PNO-OSP-88-018A, PNO-OSP-88-18A, NUDOCS 8811230050
Download: ML20206G977 (1)

Text

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November 21, 1908 PRILIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNO-0SP-88-018A This preliminary notifiution constitutes EARLY notice of events of POSSIBLE safety or ,

public interest significance. The information is as initially ree<ived without verifi-cation or evaluation, and is basically all that is known by OSP staff on this date. j FACILITY: Tennessee Valley Authority Licensee Emergency Classification:

Sequoyah Units 1 and 2 Notification of Unusual Event ,

Docket Nos. 50-327 and 50-328 Alert '

Soddy Daisy, Tennessee Site Area Emergency General Emergency

_X _Not Applicable i

SUBJECT:

SEQUOYAH UNIT 1 REACTOR TRIP UPDATE On November 18, at 10:04 a . n. (EST), Unit 1 tripped from 72*; reactor power upon receipt of a turbine trip signal. The root cause was determined to be  :

an electrical ground in the main generator. The grounded condition resulted in an  ;

overvoltage on the m:in generator neutral transferrer causing the generator output  :

breakers to open initiating a turbine trip.

The licensee completed a controlled cooldown to mode 5. The licensee has initiated outage work including repair of the main generator, repair of the RCP #3 seal l package, repair of all steam dumps, evaluate RC3 pressure vessel o-ring leakage, and repair several safety valves. Current schedule for restart is approximately '

December 17, 1988. [

This PN is current as of 11:00 a.m. (EST) on November 21, 1988. .[

t CONTA;T: S. Richardson  !

49-23286 I DISTRIBUTION 5520: Mail: ,

LTaTrnan Zech - INRC1718/ZECHPN ICIS  !

Comissioner Roberts - INRC1718/Leadop '

DCS l Comissioner Carr - INRC1718/CARRPN OIA-kNBB-8607 Comissioner Rogers - INRC1718/Leadop O!- 3E4-DLewis Comissioner Curtiss - 1NRC1718/Leadop OSP SECY - INRC1718/Leadop CA - INPC1718/0CAPN PA - INRCO?/0PADN ARM - NPCRM/Browr, Reginnal Offices AEOD - NRCAF0D/AE0DPN Region I - RI/Leadop Pqs Oper. Office - NRCAE00/AEODPN Reoion !! - RII/Leadop NRR - INRC1112/NRRPN Sequoyah Resident Inspector OE - INRC0708/0EPN Licensee: TVA LMSS - INRC0506/hM*SPN Region III - PIII/Leadop OGC - INRC1516/0GCPN Degion IV - RIV/Leadop SP - INRC0304/SLIPN 9ecien V - RV/Leadep EPO - 1NRC1718/EDOPN DEDRO - INRC1'18/E00PM GPA - INDC1718/0CAPN oES - NRCRES/RESPN 4 s g 12 p o esing I ruo-ose-es-01e roc g

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