PNO-III-15-006, Davis-Besse Shutdown Due to Secondary Side Steam Line Rupture
| ML15133A223 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 05/13/2015 |
| From: | Jamnes Cameron Reactor Projects Region 3 Branch 4 |
| To: | |
| References | |
| PNO-III-15-006 | |
| Download: ML15133A223 (2) | |
PRELIMINARY NOTIFICATION May 13, 2015 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE-PNO-III-15-006 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. Some of the information may not yet be fully verified or evaluated by the Region III staff.
Facility Davis-Besse, Unit 1 FirstEnergy Nuclear Operating Co.
Oak Harbor, OH Docket: 50-346 License: NPF-3 Licensee Emergency Classification X Notification of Unusual Event Alert Site Area Emergency General Emergency Not Applicable
SUBJECT:
SHUTDOWN OF DAVIS-BESSE DUE TO SECONDARY SIDE STEAM LINE RUPTURE On May 9, 2015, at 5:56 pm CDT, the control room operators heard the sounds of rushing air or steam in the turbine building and began an investigation. The operators observed steam on the turbine deck and began a controlled power decrease. At approximately 30 percent reactor power the operators initiated a manual reactor trip in accordance with plant procedures. All equipment operated properly.
Once the plant was shut down workers isolated the condenser and cooled the reactor using the atmospheric relief valves. This caused a steam release to the environment as expected for this type of shutdown.
During the event, steam from the rupture of the 4-inch diameter pipe caused the fire suppression system to actuate, however; there was no fire in the area. The pipe was non-safety related and carried secondary side steam. Some non-safety related breakers and motor control centers were wetted as a result of the sprinkler system being actuated. Equipment affected by the steam line failure is being evaluated prior to being returned to service.
At approximately 6:10 pm CDT the licensee declared a Notification of Unusual Event (NOUE).
The NOUE was terminated at 8:21 pm CDT. No personnel were injured.
NRC inspectors responded to the site upon notification and are continuing to monitor the licensees corrective actions.
The licensee is assessing the causes of the failure to identify the thinning pipe prior to its failure and any extent of condition. The licensee has completed the repair of the failed section of piping. The licensee restarted the unit on May 11, 2015, at 5:15 pm CDT and is currently raising power.
PRELIMINARY NOTIFICATION This preliminary notification is issued for information only.
NRC received initial notification of this occurrence by a member of the public that had called the NRC Headquarters Operations Officer. The licensee subsequently informed the NRC within the one hour required by NRC regulations. The information presented herein has been discussed with the licensee, and is current as of 2:30 p.m. CDT, on May 12, 2015.
ADAMS Accession Number: ML15133A223 Contacts:
Jamnes Cameron 630-829-9833 Jamnes.Cameron@nrc.gov