View source for PNO-V-87-018, on 870301,1-2 Mw/Min Shutdown Initiated to Investigate & Repair Main Generator Hydrogen Coolant Leak. Vibration,Induced by Main Generator,Caused Cracking in Welds of Stator Cooling Water Sys Which Occurred on 870217

{{Adams
| number = ML20212K967
| issue date = 03/02/1987
| title = PNO-V-87-018:on 870301,1-2 Mw/Min Shutdown Initiated to Investigate & Repair Main Generator Hydrogen Coolant Leak. Vibration,Induced by Main Generator,Caused Cracking in Welds of Stator Cooling Water Sys Which Occurred on 870217
| author name = Mendonca M, Padovan M
| author affiliation = NRC OFFICE OF INSPECTION &amp; ENFORCEMENT (IE REGION V)
| addressee name = 
| addressee affiliation = 
| docket = 05000323
| license number = 
| contact person = 
| document report number = PNO-V-87-018, PNO-V-87-18, NUDOCS 8703090476
| 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 0F EVENT.0R' UNUSUAL OCCURRENCE--PNO-V-87-18                                                                  Date 03/02/87
,.        iThis ? preliminary notification constitutes EARLY notice of' events of POSSIBLE safety or public
          ; int: rest significance. The information presented is as initially received without verification cr evaluation 'and is basically all that is 'known- by Region V staff on this date.
FACILITY: PACIFIC GAS & ELECTRIC COMPANY'          ~
                                                                                                                           -Emergency Classification DIABLO CANYON UNIT 2                                                                             Notification of Unusual Event DOCKET NO. 50-323                                    ^
Alert                                  .-
!                             ' SAN LUIS OBISPO COUNTY, CA                                                                       Site Area Emerg'ency General Emergency-TNot Applicable

==SUBJECT:==
SHUTDOWN'FOR GREATER THAN 48 HOURS-                                                                                                                                   ,
         ~'Diablo Canyon _ Unit 2 initiated a-1-2 MW/ MIN shutdown-from 100% power at 3':00 am (PST) on March 1,1987 to investigate and repair a main generator hydrogen coolant leak.
hydrogen was leaking into the ~ stator cooling water system at a constant rate of . The approximately 3.5 SCFM, and was vented to the atmosphere above the turbine building.
The licensee postulates'that vibration, induced by.the main generator, had caused cracking in welds of the stator cooling water system. This occurred earlier, on February 17, and .
     - 'the unit was shut down to about 2%' power for five days to repair a 11 inch cracked weld.on ca . stator water sparger ring in. the generator. .
The generator was taken offline at 12:33 pm on March 1, and the reactor will be maintaine'd at about 1-2% power throughout the outage. The' licensee predicts a 4 day outage at this time.-
This information -is current as of 9:00 am (PST) on March 2,1987.
The licensee has issued a pre'ss release.
         ' CONTACT:           M. Mendonca, RV                                          M. Padovan FTS 463-3720                                             805-595-2354 DISTRIBUTION
        -H St.                           MNBB             Phillips / 7f E/W                        Willste                   Air Rights h Mail:
:       ? Chairman Zech                      EDO             .NRR              IE                   NMSS                                                             ADM:DMB 1
Comm. Roberts                           PA'                                   OIA                     RES                                                       D0T:Trans Only Comm. Asselstine                 MPA                                AE0D Comm. Bernthal                   OGC Comm. Carr                                   ,   , Regions:
SECY                                                 INP0 Z o.f NSAC 2 *.o/
        -ACRS-                                                  Licensee: 2:J 7
         'CA                                                .(Reactor Licensees)                                      REGION V: FORM 211 PDR                                                 Resident Inspector _                                            (Revised 3/14/83)
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