PNO-I-12-006, Three Mile Island Shutdown Due to Reactor Coolant System Leak
| ML12236A345 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 08/23/2012 |
| From: | Hunegs G NRC/RGN-I/DRP/PB6 |
| To: | |
| HUNEGS, GK | |
| References | |
| PNO-I-12-006 | |
| Download: ML12236A345 (2) | |
Date: August 23, 2012 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE -- PNO-I-12-006 This 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 I staff on this date.
Facility Licensee Emergency Classification Exelon Generation Company, LLC Three Mile Island Unit 1 Middletown, PA Docket: 50-289 License: DPR-50
_ Notification of Unusual Event
_ Alert
_ Site Area Emergency
_ General Emergency X Not Applicable
SUBJECT:
THREE MILE ISLAND SHUTDOWN DUE TO REACTOR COOLANT SYSTEM LEAK On August 22, 2012, at 4:58 a.m., operators at Three Mile Island Unit 1 commenced a Technical Specification-required shutdown due to an indication of reactor coolant system leakage. Exelon reached this conclusion after reviewing remote video camera inspection results from inside the secondary shield wall within the reactor building. The video showed leakage from a pressurizer heater bundle which is both bolted and welded to the pressurizer housing. The leak rate at the time of the shutdown was stable at 0.17 gallons per minute (gpm).
During the power reduction, at 8:01 a.m., an automatic reactor trip occurred from 30 percent power. The cause was a failure of a secondary plant control relay which resulted in a feedwater transient. The emergency feedwater system actuated, as expected. All control rods fully inserted and decay heat was being removed through the normal heat removal process. All plant systems functioned normally following the trip except manual operation of the turbine bypass valves was required due to failure of the automatic control function. The unit is stable. There was no impact on public health and safety. Exelon is evaluating plans to repair the leak.
The senior resident inspector has been on site reviewing ongoing licensee actions and monitored the shutdown. The NRC will continue to evaluate the event, including repair activities.
The Commonwealth of Pennsylvania was informed of the event. The NRC Region I Public Affairs Office responded to media inquiries.
The information presented herein was discussed with Exelon and was current as 11:45 a.m.,
August 23, 2012.
ADAMS Accession Number: ML12236A345 CONTACT:
Gordon Hunegs (610) 337-5046
ML12236A345 x SUNSI Review Non-Sensitive Sensitive Publicly Available Non-Publicly Available OFFICE RI/DRP RI/SLO RI/PAO RI/DRP RI/DRP RI/ORA NAME SBarber/ SB DTifft/ GKH for DScrenci/DS GHunegs/GKH DRoberts/ GTD for WDean/DCL for DATE 08/ 22 /12 08/23 /12 08/ 23 /12 08/23 /12 08/23 /12 08/ 23/12