View source for PNO-V-86-049, on 860729 & 30,pressure Transmitter 459 Failed Low Resulting in Steam Flow/Feed Flow Mismatch Trip Circuits Becoming Inoperable.Caused by Failed Electric Card in Pressure Transmitter Amplifier.Amplifier Replaced

{{Adams
| number = ML20204F277
| issue date = 07/30/1986
| title = PNO-V-86-049:on 860729 & 30,pressure Transmitter 459 Failed Low Resulting in Steam Flow/Feed Flow Mismatch Trip Circuits Becoming Inoperable.Caused by Failed Electric Card in Pressure Transmitter Amplifier.Amplifier Replaced
| author name = Huey R, Narbut P
| author affiliation = NRC OFFICE OF INSPECTION &amp; ENFORCEMENT (IE REGION V)
| addressee name = 
| addressee affiliation = 
| docket = 05000206
| license number = 
| contact person = 
| document report number = PNO-V-86-049, PNO-V-86-49, NUDOCS 8608040141
| 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 OF EVENT OR UNUSUAL OCCURRENCE--PNO-V-86-49                      Date:07/30/86 Thic preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information presented is as initially received without verification or ovaluation and is basically all that is known by Region V staff on this date.
FACILITY: Sauthern California Edison Company                           Licensee Emergency Classification San Onofre Unit 1                                          XX Notification of Unusual Event DOCKET NO. 50-206                                               Alert Site Area Emergency t
General Emergency Not Applicable

==SUBJECT:==
UNUSUAL EVENT AT SAN ONOFRE UNIT 1 DUE TO PRESSURE TRANSMITTER FAILURE At 1935 PDT on 7/29/86 a temporary rapid decrease in steam flow signals caused a sharp reduction in fasdwater flow to all three steam generators.(SG's).             As a result, narrow range level in all SG'o decreased, due to reduction in feed flow, to the automatic Auxiliary Feedwater System (AFW) cctpoint of 5% and both AFW trains actuated. Af tar taking manual control of the feedwater control system, normal SG operating levels were restored. The unit power was reduced as a praceutionary measure and feedwater control was returned to automatic. Pressure transmitter (PT) 459 was the suspected cause and maintenance orders were initiated.
At 0103 PDT on 7/30/86, PT 459 failed (spiked) low again which resulted in all three steam flow / feed flow mismatch trip circuits becoming inoperable. Since an operator was stationed at tha feedwater control station, control was immediately shifted to manual. An Unusual Event was dsclared at 0203 and the licensee commenced a shutdown as required by Technical Specifications.
The problem with the pressure transmitter was determined to be a failed electronic card in the explifier.
Tha Unusual Event was terminated at 0350 PDT on 7/30/86 when the amplifier for the transmitter was replaced. The shutdown was terminated and the licensee is in the process of restoring power.
The licensee classified the event an Unusual Event based on the Emergency Safety Feature system
 ,  cctuation.
Tha licensee has prepared a statement for use in response to media inquiries. Region V PA0 expsets press interest.
This information is current as of 1030 PDT, 7/30/86.
4 CONTACT:    P. Narbut                             R. Huey FTS 463-3730                          (714) 492-2641 DISTRIBUTION H St.                   MNBB    Phillips           E/W     Willste       Air Rights //I#T Mail:
Chmirman Zech           EDO        NRR             IE        NMSS                             ADM:DMB Comm.                   PA                         OIA       RES                              DOT:Trans Only Comm. Bernthal           MPA                        AEOD Comm. Roberts            ELD Comm. Asselstine                    Regions:
SECY                                INPO //.*cf7 NSAC ///or' ACRS                                Licensee:
1 CA                                  (Reactor Licensees)               REGION V: FORM 211 PDR                                 Resident Inspectorfj[lJD               (Revised 3/14/63)
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8603040141 860730 PDR      I&E                                                                                  ()I l PNO-V-86-049 PDR
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