PNO-III-89-050A, on 890801,turbine Driven Reactor Feedwater Pump B Started to Act Erratically While Operating at 98% Power.Licensee Currently Investigating Cause of Problem.Flow Control Valve Opened & Recirculation Pump a Restarted

PNO-III-89-050A:on 890801,turbine Driven Reactor Feedwater Pump B Started to Act Erratically While Operating at 98% Power.Licensee Currently Investigating Cause of Problem.Flow Control Valve Opened & Recirculation Pump a Restarted

ML20245J436
Person / Time
Site:	LaSalle
Issue date:	08/02/1989
From:	Harrison J, Shafer W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
References
PNO-III-89-050A, PNO-III-89-50A, NUDOCS 8908180030
Download: ML20245J436 (2)

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PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL.0CCURRENCE PN0-III-89-50A Date August 2, 1989 This-preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public in'terest significance. The information is as initially received without verification or evaluation, and is basically all that is known by the Region III staff on this date.

Facility: Commonwealth Edison Co. Licensee Emergency LaSalle Unit 2 Classification:

Marseilles, IL 61341 Unusual Event L Alert @#

Docket No. 50-374 Site Area Emergency General Emergency X Not Applicable

Subject:

OPERATION OF REACTOR IN THE STABILITY MONITORING ALLOWABLE REGION At 1:52 p.m. (CDT), August 1, 1989, while the reactor was operating at 58 percent power, the licensee noted that the B Turbine Driven Reactor Feedwater Pump was acting erratically. l The operator had just changed level control and had just placed the A feedwater pump into automatic (the B pump was still in manual). About 30 seconds later, the flow from the B pump increased and did not consistently respond to operator actions. The operator returned the A pump to manual and tripped the B pump. A motor-driven feed pump was then started to assist in providing feedwater to the reactor. Reactor power was manually reduced to about 56 percent when the reactor entered the stability monitoring allowable region. The reactor operator then fnserted a pre-determined array of control rods in order to exit this region.

The reactor was not operated in the restricted region. The reactor was in this region of operation for approximately 15 minutes, and exited the region with reactor power at 43 percent.

During this event, the raactor water level varied between 18 inches below normal and 15 inches above normal (the reactor would have automatica11y scrammed if the water level had dropped to 23) inches below normal). A runback (partial closure) of the A reactor i recirculation flow contr>l valve also occurred causing a mismatch in flows between the two recirculation loops of greater than 10 percent flow.

At 2:10 p.m., the licensee entered the two-hour limiting condition for operation (LCO) to correct the mismatch or declare the A recirculation loop inoperable. At 4 p.m., the licensee tripped the A reactor recirculation pump so that the flow control valve could be opened. This terminated the two-hour clock but started the four-hour LCO for being in a

. single loop operation.

At 4:05 p.m., the flow control valve was opened, the A recirculation pump restarted, and the four-hour LCO terminated.

The licensee is currently investigating the cause of the 8 feedwater pump problem. The  !

runback of the A recirculation flow control valve may have been caused by a higher than normal level reset point in the runback logic.

' DISTR GUTION:

WHilf FLINT NORTH 1 MNB8 REGIONS FAX TO:

Dii E sn Carr LA XEUU RI TKPDW.W Comm. Roberts OGC ARM RII NSAC 4/#5 Comm. Rogers 0I OIA RIV Licensee NN 4 Comm. Curtiss EDO RV NRC Ops Ctr /M l SECY NRR NL MAIL T0: PDR (8/634-u 37 4 # 4g ti GPA/SLITP/PA hMSS RES DCS (Orig.)

ALSAP ACRS DOT (Trans. Gnly) p 'I ; i DE 8908100030 8ms02 Rev. 07/05/89 PDR I&E PNO-I I I OM i iC j i

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- PREdNIWARY- NOTIFICATION OF EVENT OR UNUSDAL' OCCURRENCE--PNO-111-89-50 Date August 92 1989

+. o;

The Senior Resident Inspector was in the control room during this event. fA Region III

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L' insp$ctor has been sent to the site to monitor the licensee's investigation'of this

. incident.- A representative from NRR also is on site.

'The State of Illinois till be notified.

RGgion III first learned of this event at 2:30 p.m. (CDT), August 1, 1989. This information is current as of 12: 15 p.m. (CDT), August 2, 1969.

t/

CONTACT: l

. Harrison . shafer FTS 388-5635 FTS 388-656 i

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