View source for PNO-IV-97-038, on 970629,Unit 2 Entered Mode 3 & Mode 4 in Preparation for Draining to Midloop.Two Charging Lines to RCS Did Not Have Balanced Flow.Same Valve Was Found to Be Partially Stuck Closed in Units 2 & 3.Plant Shutdowned

{{Adams
| number = ML20141E793
| issue date = 06/30/1997
| title = PNO-IV-97-038:on 970629,Unit 2 Entered Mode 3 & Mode 4 in Preparation for Draining to Midloop.Two Charging Lines to RCS Did Not Have Balanced Flow.Same Valve Was Found to Be Partially Stuck Closed in Units 2 & 3.Plant Shutdowned
| author name = Kirsch D, Sloan J
| author affiliation = NRC OFFICE OF INSPECTION &amp; ENFORCEMENT (IE REGION IV)
| addressee name = 
| addressee affiliation = 
| docket = 05000361, 05000362
| license number = 
| contact person = 
| document report number = PNO-IV-97-038, PNO-IV-97-38, NUDOCS 9707010161
| document type = PRELIMINARY NOTIFICATION OF EVENT OR OCCURRENCE (PNO,, TEXT-INSPECTION &amp; AUDIT &amp; I&amp;E CIRCULARS
| page count = 1
}}
{{#Wiki_filter:= _ ~          -          _ - .        .     .   .-    -._ ____
ff June 30,1997
   ,   PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNO-IV-97-038 This preliminary notification constitutes EARLY notice of events of POSSIBLE l
safety or public interest significance. The information is as initially                               I received without verification or evaluation, and is basically all that is                            i known by Region IV staff in Arlington, Texas on this date.                                            I Facility                           Licensee Emeroency Classification Southern California Edison & San Diego Gas        Notification of Unusual Event
       & Electric Co.                                              Alert San Onofre 2 3                                              Site Area Emergency San Clemente, California                                    General Emergency Dockets: 50-361,50-362                                      X Not Applicable

==Subject:==
UNIT 2 FORCED SHUTDOWN REQUIRED BY TECHNICAL SPECIFICATIONS On June 29,1997, at 3:48 p.m. (PDT) Unit 2 entered Mode 3 and at 11:17 p.m. (PDT) entered Mode 4 in preparation for draining to midloop. Unit 2 had been at full power, and initiated the shutdown in accordance with Technical Specifications. Licensee personnel had determined that the two charging lines to the reactor coolant system did not have balanced flow. Valve 2MUO21, a charging system injection check valve to cold leg loop 1 A, was found to be partially stuck closed, forcing most of the charging flow through the other injection path to cold leg loop 2A. This was contrary to the assumptions associated with Charging flow for the small break loss of coolant accident analysis.
The licensee plans to enter midloop operations on Unit 2 when decay heat permits, to either repair or replace valve 2MUO21. Plant restart has not yet been scheduled.
Unit 3, which was shutdown for the Cycle 9 refueling outage, also had the same cold leg 1 A injection check valve partially stuck closed. On June 28,1997, Unit 3 was placed in midloop, and on June 29,1997, Unit 3 valve 3MUO21 was cut out. The licensee is                       '
considering replacing valve 3MUO21 with a valve of a different design.
The licensee is evaluating the other applications for this valve in the plant to determine            l whether any additional corrective actions are required for the valves in other locations.             1
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The state of Californir. has been informed.                                                           !
Region IV received notification of this occurrence by telephone from the SRI on June 29, 1997. Region IV has informed OEDO, NRR and PAO.
This information has been discussed with the licensee and is current as of 8:30 a.m. (PDT) on June 30,1997.

==Contact:==
Dennis Kirsch           Jim Sloan (510)975-0290          (714)492-2641 9707010.
PDa      1
                   ,161 970630
                                                                                                 \d ok PNO-IV-97-030          PDR U A U U .' l}}

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