ML13316C262
| ML13316C262 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 11/12/2013 |
| From: | Division Reactor Projects II |
| To: | |
| References | |
| PNO-II-13-008 | |
| Download: ML13316C262 (1) | |
Text
November 12, 2013 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE - PNO-II-13-008 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 II staff (Atlanta, GA).
Facility:
Licensee Emergency Classification:
Plant Oconee Notification of Unusual Event Unit 1 Alert Location Seneca, SC Site Area Emergency Docket No (s): 50-269 General Emergency X
Not Applicable
SUBJECT:
OCONEE UNIT 1 SHUTDOWN DUE TO REACTOR COOLANT SYSTEM (RCS)
PRESSURE BOUNDARY LEAKAGE On November 9, 2013, the licensee observed indications of an RCS leak when the containment process radiation monitor (RIA-47) alarmed. Over the next 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, the unidentified leak slowly increased from 0.007 gallons per minute (gpm) to 0.126 gpm. Soon after the rate increased above 0.007 gpm, the licensee implemented their procedures for identifying and isolating such a leak.
The licensee entered containment on November 10 and discovered water on the Reactor Building floor. The licensee used a robot to enter the area below the steam generators and found water under the 1B steam generator and reactor coolant pumps. The licensee identified the source as a steam leak where high pressure injection (HPI) injects into the RCS cold leg.
This was determined to be RCS pressure boundary leakage. The licensee shut down the unit as required by technical specifications. Currently, Unit 1 is in MODE 5 with reactor coolant system temperature approximately 150 degrees F. The licensee estimates repairs will exceed 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
The resident inspectors continue to monitor the licensees actions and the NRC regional office is considering additional inspection activities. The State of South Carolina was contacted by email and during a subsequent phone call requested no further follow-up. A press release by Region II is not planned for this event.
This preliminary notification is issued for information only.
Region II received initial notification of this occurrence through the resident inspector who had been informed via telephone by the licensee on Sunday, November 10 at 9:00 am. The information presented herein has been discussed with the licensee and is current as of 10:00 a.m., November 12, 2013.
ADAMS Accession Number: ML13316C262 CONTACT:
Gerald McCoy 404-997-4551 Gerald.McCoy@nrc.gov