View source for PNO-II-93-007, on 930204,plant Commenced Power Reduction Due to Identified Steam Leakage on 1B1 MSR High Pressure Operating Vent Line.Resident Inspectors Have Been Following Licensee Actions.State of Tn Not Required to Be Informed

{{Adams
| number = ML20203G168
| issue date = 02/04/1993
| title = PNO-II-93-007:on 930204,plant Commenced Power Reduction Due to Identified Steam Leakage on 1B1 MSR High Pressure Operating Vent Line.Resident Inspectors Have Been Following Licensee Actions.State of Tn Not Required to Be Informed
| author name = Kellogg P
| author affiliation = NRC OFFICE OF INSPECTION &amp; ENFORCEMENT (IE REGION II)
| addressee name = 
| addressee affiliation = 
| docket = 05000327
| license number = 
| contact person = 
| document report number = PNO-II-93-007, PNO-II-93-7, NUDOCS 9712180067
| document type = PRELIMINARY NOTIFICATION OF EVENT OR OCCURRENCE (PNO,, TEXT-INSPECTION &amp; AUDIT &amp; I&amp;E CIRCULARS
| page count = 2
}}
{{#Wiki_filter:_                                                       _
a,                      j)MMI h lY February                 4,          1993
  ;    8RELIMIMARY. NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PHO-II-93-007 1his preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information is as initially received without verification or evaluation, and is basically all that is known by the Region II staff on this date.
IsollitY                                        kicensee Emercency classification Tennessee Valley Authority                          Notification of Unusual Event Sequoyah 1                                          Alert Soddy-Daisy, Tennessee                              Site Area Emergency Dockets: 50-327                                     General Emergency X Not Applicable

==Subject:==
POWER REDUCTION / FORCED OUTAGE GREATER THAT 72 HOURS DUE TO LEAK ON 1B1 MSR HIGH PRESSURE OPERATING VENT LINE.
On Febitary 4, 1993 at approximately 2:00 pm, Sequoyah, Unit 1 commenced a power reduction due to identified steam leakage on the 1B1 MSR high pressure operating vent line. The leak was not isolable from the high pressure turbine extraction steam line and efforts to effect a repair at full power were not attempted due to the steam hazard. The leak was identified at a piping location whicd"had been temporarily repaired
      ,turing past operation and was not isolable from main turbine extraction iteam. The licensee believes that the leak was caused by erosion of the [.',
piping at a location where they have seen similar piping failures on                                                r other components during past operating cycles. Licensee management                                                '$P,~; t, decided to place Unit 1 in MODE 3, break condenser vacuum, and make a permanent repair at this time. Steam leakage in the turbine building had not effected any safety systems.
As of 4:00 pm on February 4, 1993, Unit 1 was at approximately 90 percent power with unit shutdown continuing and preparations being made to establish conditions to commence work. The forced outage is expected to take approximately 3 days.
Unit 2 operated at approximately full power throughout the event and was not affected.
Regional action: Resident inspectors have been following licensee's actions. A region based inspector is on site reviewine the licensee's
       . erosion / corrosion program and will monitor selected licensee activities during the forced outage.
The licensee will make notification to local media with regard to Unit i shutdown and outage related work.
The State of Tennessee was not required to be informed, nor were they informed by the licensee of the forced outage.
C/R DISTRIBUTION:
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      ,,,'?S                                          ;gr- SECY, RECORDS 9712180067 930204                                                 -
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This'information'is,currentLas'of 4:00 pa on February 4,:1993.--                                                                                                                       -
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                          .y'iContactt: - P. J'.'KELf40G           - .
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