View source for PNO-V-86-083, on 861119,facility Tripped on Steam Generator 1 Low Level.Caused by Failure of narrow-range Level Instruments & Steam Generator Level Oscillations.Plant Currently in Mode 3 Preparing for Restart by 861121

{{Adams
| number = ML20214K171
| issue date = 11/20/1986
| title = PNO-V-86-083:on 861119,facility Tripped on Steam Generator 1 Low Level.Caused by Failure of narrow-range Level Instruments & Steam Generator Level Oscillations.Plant Currently in Mode 3 Preparing for Restart by 861121
| author name = Richards S, Zimmerman R
| author affiliation = NRC OFFICE OF INSPECTION &amp; ENFORCEMENT (IE REGION V)
| addressee name = 
| addressee affiliation = 
| docket = 05000528
| license number = 
| contact person = 
| document report number = PNO-V-86-083, PNO-V-86-83, NUDOCS 8612020200
| document type = PRELIMINARY NOTIFICATION OF EVENT OR OCCURRENCE (PNO,, TEXT-INSPECTION &amp; AUDIT &amp; I&amp;E CIRCULARS
| page count = 1
}}
{{#Wiki_filter:r. E     ' <
4 4
k
[-      f M                      L PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-V 83 Date: 11/20/86 Thio preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public intcrest significance.- The information presented is as initially received without verification er cvaluation and is basically all that is known by Regica V staff on this date.
FACILITY: Arizona Nuclear Power Project                           Emergency Classification Palo Verde Unit 1                                       Notification of Unusual Event DOCKET NO. 50-528                                       Alert Site Area Emergency General Emergency
_X_Not Applicable

==SUBJECT:==
REACTOR TRIP AT PALO VERDE UNIT 1 At cpproximately 11:15 AM MST, November 19, 1986, Palo Verde Unit I tripped on steam g:n:rator #1 low level. Prior to the trip, both narrow range level instruments for steam gansrator il failed low, simultaneously. This resulted in a feed flow / steam flow mismatch in ctorm generator fl.      In response to this, the operator took manual control and reduced flow to cteam generator #1 using a feedwater control valve. This resulted in steam g:nnrator level oscillations which caused a low level in steam generator #1 and a high leval in steam generator #2. (The high level in steam generator #2 was due to additional flow being directed to steam generator #2 when the feedwater flow for steam generator #1 was reduced). The low level in steam generator #1 tripped the reactor and resulted in an cuxiliary feedwater actuation signal. The high level in steam generator #2 caused a main sesam isolation. All systers performed as required.
Th2 plant is currently in Mode 3 making preparations for restart. The two narrow range secsm generator level instruments apparently failed due to a blown fuse in the power centrol logic for the subject instruments. The instruments are not safety related,
:     howsver, they provide a control and indication function. The licensee is attempting to datormine why the fuse blew. Plant restart is not expected until late on Nsv;mber 20 or early on November 21.
This information is current as of 12:00 NOON, PDT, on November 20, 1986.
1 CONTACT:     R. Zimmerman, Sr. Resident Inspector        S. Richards l                  (602) 386-5760                              (415) 943-3853                  '
l DISTRIBUTION l
H St.                  MNBB      Phillips 5
                                               ? CE/W       Willete      Air Rights IO/ Mail:
Chairman Zech            EDO       NRR          IE       NMSS                        ADM:DMB Comm. Roberts           PA                      OIA      RES                         DOT:Trans Only C:mm. Asselstine        MPA                     AEOD Comm. Bernthal          ELD r    Comm. Carr              Regions:                    _
SECY                               INP0flo3 NSAC 6 /0 y ACRS                               Licensee: /2.*J C CA                                 (Reactor Licensees)          REGION V: FORM 211 PDR                                Resident Inspector                 (Revised 3/14/63)
Operations Center, Hqs. [ k 0612O20200 861120 PDR      ILE PNO-V-86-083          PDR}}

{{PNO-Nav|region=V}}