ML20212A499

PNO-ADSP-90-013:on 900509,reactor Trip on Low SG Level. Initial Reactor Power Was 48%.Transient Was Initiated by Loss of Speed Control on Both Main Feedwater Pumps

ML20212A499
Person / Time
Site:	Comanche Peak
Issue date:	05/11/1990
From:	Johnson W, Joel Wiebe NRC
To:
References
PNO-ADSP-90-013, PNO-ADSP-90-13, NUDOCS 9710230332
Download: ML20212A499 (1)

Text

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hd.utt (2 Y May 11, 1990 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PH0-ADSP-90-13 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information is as initially received without verification or evaluation, and is basically all that is known by the ADSP staff on this date.

FACILITY: TU Electric Licensee Emergency Classification:

• Comanche Peak Unit 1 Notification of Unusual Event Docket No. 50sS 5 Alert Glen Rose, Tex 61 Site Area Emergency General Emergency X Not Applicable

SUBJECT:

REACTOR TRIP INITIATED BY LOSS OF SPEED CONTROL ON BOTH MAIN FEEDWATER PUMPS At3:05p.m.,(CDT)onMay9,1990,thereactortrippedonlowsteamgenerator level. Initial reactor power was 48%. The transient was initiated by loss of speed control on both main feedwater pumps. >

MFW pump speed decreased causing a reduction in MFW flow. Main feedwater isolation valves closed when flow decreased below the interlock setpoint. The main turbint was manually tripped and auxiliary feedwater pumps (motor driven) were started by the operators. A reactor trip on low steam generator level occurred while the operator was executing a manual reactor trip. The turbine driven AFW pump started on low steam generator level. y#

All systems responded per design and the plant was stabilized in Mode 3.

loss of MFP speed control was caused by an error in a calibration procedureThe l %

which was being performed on a pressure input to MFP speed control circuitry.

Three site NRC personnel were in the control room within five minutes of the trip. They witnessed the plant stabilization and observed the licensee's effort to determine the cause of the trip.

After conclusively-determining the cause of the trip, and after performing the pressure transmitter calibration, the licensee commenced a reactor startup.

Criticality was achieved at 1:34 p.m. (CDT) on May 10, 1990.

This PN is being issued because of media interest. Localmediahadorihna119 not expressed any interest. However, on May 10, interest was expressed Neither the NRC or the licensee plan to issue a news release. BothwillrerponEtop inquiries. - ,

vi The State of Texas will be informed. 2

-a Theinformationpresentedhereinhasbeendiscussedwiththelicenseea$is currentasof4:00p.m.(CDT)onMay 10, 1990.

CONTACT: J. Wiebe 817)897-1500 W. Johnson. 817)897-1500 i, C/R Distribution: Chm, Cmrs '

. GPA, GC. CA, PDR, Historian, go2g32900511 SECY, Records.

PNO-ADSP-90-13 PDR J