View source for PNO-V-86-012, on 860327,loss of Both Shutdown Cooling Trains Experienced Due to Loss of Pump Suction & Cavitation.Caused by Reactor Vessel Water Vortexing Causing Air to Be Pulled Into Shutdown Cooling Lines

{{Adams
| number = ML20140J542
| issue date = 03/28/1986
| title = PNO-V-86-012:on 860327,loss of Both Shutdown Cooling Trains Experienced Due to Loss of Pump Suction & Cavitation.Caused by Reactor Vessel Water Vortexing Causing Air to Be Pulled Into Shutdown Cooling Lines
| author name = Chaffee A, Narbut P
| author affiliation = NRC OFFICE OF INSPECTION &amp; ENFORCEMENT (IE REGION V)
| addressee name = 
| addressee affiliation = 
| docket = 05000361
| license number = 
| contact person = 
| document report number = PNO-V-86-012, PNO-V-86-12, NUDOCS 8604040354
| document type = PRELIMINARY NOTIFICATION OF EVENT OR OCCURRENCE (PNO,, TEXT-INSPECTION &amp; AUDIT &amp; I&amp;E CIRCULARS
| page count = 1
}}
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PRELIMINARY NOTIFICATION EVENT OR:UNOSUAL OCCURREN'CE-PNO-V-86-12                                                   Dates.03/28/86
                    .               .. .        _.            /                   .;- .i             : m,,
     ; Thia preliminary notification constitutes EARLY notic',of                                      events off OSSIBLE             safet'y or public i e                            P Tintsrsst significance. The information' presented is as initially received without. verification lcr:cysluation and is basically-all that is_known by Regio'n V staff on this:date.
                                                                   ,          ,.    ,,2      i 4.; FACILITY: Southern California Edison Company                                                          Licensee Emergency Classification San Onofre Unit s                 .           .                       Notification of Unusual Event.
                                                                 ~                             '
DOCKET NO.'50-361                                                           -
Alert Site. Area Emergency "
    ,^
General Emergency XX Not Applicable-

==SUBJECT:==
LOSS'0F SHUTDOWN' COOLING I
Tha unit has been shu'tdown for a refueling outage'since'3/15/86. -On the. evening of23/26/86.
       'chutdown cooling was'in operation with the unit in Mode 5 with the Reactor Vessel head installed
    .'                                                                                                                    At 00:50 EST 3/27/86, the l;cndeithwaterlevelat82inchesbelowtheReactorVesselflange.
unit had a loss of both trains of shutdown cooling because of loss of pump suction and pump a cavitation.:.This was apparently caused by reactor vessel water vortexing causing air.to be pulled into the shutdown cooling lines'. The LPSI pump No. 16 was manually stopped. -Pump starts?
      ;cf LPSI pump Nos. 15 & 16 were made but did not resolve the' air binding. The line was then uvantid and the reactor vessel water level was raised .2 inches. The No. 16 LPSI pump' was regterted and:is operating without further problems. The entire event was less than I hour in-
      ; duration. The bulk RCS temperature rose from 115'F to 180'F_during the event, as' reported to
:tha hsadquarters' duty officer by licensee staff. The resident inspectors have been examining tha cvent including review of data and interviews of personnel. At this time unresolved quistions exist which will be pursued.                         It appears that a possibility exists that saturation temparatures may have been reached in local areas of the core based on a Th reading of 210'F
     - during the period no ' flow was in progress.
Th2 licensee has~ determined that erroneous level readings were caused by a kink in the tygon tubs level indicator.- The kink.has been repaired. The licensee has implemented additional cdministrative controls,' including operator walkdown of the level indication system,:to prevent
     -r:currence.
:Lic3nzee management is pursuing.further definition of bulk temperatures achieved and has-dstsreined that no fuel damage cccurred due to the low heat flux values.
     'Th2 licensee plans to continue with refueling operations at this time.
Th N.information is current as of 11:00 am PST March 28, 1986.
hCONTACT: . A. Chaffee                        ,                       P. Narbut
.        s         FTS 463-3753                                      'FTS 463-3730 I DISTRIBUTION 4 H St.-                        MNBB               Phillips             E/W           Willste                Air Rights             Mail:
Chairman Palladino EDO                        NRR                   IE            NMSS                                      ADM:DMB Comm.iZech             - PA                                         OIA           RES                                       DOT:Trans Only Comm. Bernthal              MPA                                     AEOD Comm,' Roberts            ' ELD s       Comm.'Asselst'ne                              Regions:
SECY                                         'INP@.% NSAC2/ WA
    'ACRS                                             Licensee: J2.' y>/
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CA .                                          (Reactor Licensees)                              REGION V: FORM 211 PDR                                            Resident Inspector _                                        (Revised 3/14/83) 8604040354 860328                                                                                 _
PDR           I8E PNO-V-86-012                      PDR                                                                            Q   (
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