PNO-V-88-047, on 880707,cavitation of Shutdown Cooling Pump Occurred During Draindown of Reactor Vessel.Caused by Blockage of Ref Level Sensing Port in Pressurizer by Installation of Temporary Camera Mounting Bracket

PNO-V-88-047:on 880707,cavitation of Shutdown Cooling Pump Occurred During Draindown of Reactor Vessel.Caused by Blockage of Ref Level Sensing Port in Pressurizer by Installation of Temporary Camera Mounting Bracket

ML13316A449
Person / Time
Site:	San Onofre
Issue date:	07/08/1988
From:	Johnson P, Tatum J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
To:
References
PNO-V-88-047, PNO-V-88-47, NUDOCS 8807190172
Download: ML13316A449 (2)

ACCELERATED DIST BUTION DEMONSTR&ON SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:8807190172 DOC.DATE: 88/07/08 NOTARIZED: NO DOCKET #

FACIL:50-362 San Onofre Nuclear Station, Unit 3, Southern Californ 05000362 AUTH.NAME AUTHOR AFFILIATION JOHNSON,P.

Region 5, Ofc of the Director TATUM,J.

Region 5, Ofc of the Director RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

.PNO-V-88-047:on 880707,cavitation of shutdown cooling pump.

R DISTRIBUTION CODE: IE34D COPIES RECEIVED:LTR __

ENCL _

SIZE:

TITLE: Preliminary Notification-Occurrence/Non-Routine Event/Safeguards Even NOTES:

RECIPIENT COPIES RECIPIENT COPIES S

ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL INTERNAL: AEOD/DSP/TPAB 1

NRC OP CNTR 1

NRR/DOEA/EAB 11 1

NRR/DRIS/SGB 9A 1

NRR/DRIS/SIB 9A 1

NRR/PMAS/ILRB12 1

NUDOCS-ABSTRACT 1

OE LIEBERMAN,J 1

02 1

RES BROOKS,B 1

RES DEPY 1

RES FILE 1

RES/DE 1

RES/DE/EIB 1

RES/DRA 1

RES/DRAA 1

RES/DRPS 1

RES/PMPDAS 1

S RGN5 FILE 01 1

EXTERNAL: DOE BARBER EV34 1

LPDR 1

NRC PDR 1

NSIC 1

R I

D S

D D

s O

TOTAL NUMBER OF COPIES REQUIRED: LTTR. -RT ENCL 23

PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-V-88-47 Date 7/8/88 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information presented is as initially received without verification or evaluation and is basically all that is known by Region V staff on this date.

FACILITY:

SOUTHERN CALIFORNIA EDISON Emergency Classification SONGS UNIT 3 Notification of Unusual Event DOCKET NO. 50-362 Alert SAN CLEMENTE, CA Site Area Emergency General Emergency XX Not Applicable

SUBJECT:

CAVITATION OF A SHUTDOWN COOLING PUMP The Region V office was notified by the resident inspectors on July 7, 1988, that cavitation of the operating low pressure safety injection pump (used for shutdown cooling) occurred at 6:55 a.m. on July 7, during draindown of the reactor vessel.

Southern California Edison was in the process of draining the reactor vessel to mid-loop in order to facilitate replacement of the reactor coolant pump seals.

The draindown was terminated when the control room operators noticed fluctuations in indication for the shutdown cooling flow and pump running current. At this time, the installed level indications were indicating level to be at the top of the hot leg.

The operators realized that these fluctuations were indicative of pump cavitation and commenced filling the reactor vessel.

The vessel level indication system was also walked down and verified to be correctly aligned. A repeat of the experience occurred at 12:43 p.m., at the same indicated water level.

Draining was terminated and water was added again. After this occurrence, the licensee vented the level indicators to containment and determined actual level to be two inches below mid-loop.

The licensee subsequently determined that a reference level sensing port in the pressurizer had been blocked by the installation of a temporary camera mounting bracket by maintenance personnel performing work activities in the pressurizer. This caused the reactor vessel level indication to be inoperative during the draindown.

The licensee did not notify the NRC of the problems encountered until the resident inspectors reviewed the control room logs and identified the cavitation problems.

No apparent damage to the pumps occurred. The licensee initiated an investigation to determine the root cause of the pump cavitation problem. The resident inspectors and Region V are following the licensee's actions.

This information is current as of 1:00 p.m. PDT

ONTACT: P. Johnson (FTS) 463-3745 J. Tatum (714) 492-2641

)ISTRIBUTION BY 5520:

.FAX TO:

)ate 7/8/88 Time_2:30PM PDT Date Time 2hairman Zech EDO RI INPO omm. Roberts AEOD RII NSAC omm. Carr PAO RIJI LICENSEE omm. Rogers SLITP RIV RESIDENT INSPECTOR

ECY NRR HQS. OPERATIONS OFFICER A

NMSS

'DR ARM MAIL TO:,

)GC 01 CRS OIA DOT iginly Applicable State)

PA RES 80719172 RV FORM 211 PEIR I&ERevised:.

8/19/87