Morning Report for December 28, 1999
Headquarters Daily Report DECEMBER 28, 1999 *************************************************************************** REPORT NEGATIVE NO INPUT ATTACHED INPUT RECEIVED RECEIVED HEADQUARTERS X REGION I X REGION II X REGION III X REGION IV X PRIORITY ATTENTION REQUIRED MORNING REPORT - REGION II DEC. 28, 1999 Licensee/Facility: Notification: Duke Power Co. MR Number: 2-99-0016 Oconee 3 Date: 12/28/99 Seneca,South Carolina Dockets: 50-287 PWR/B&W-L-LP Subject: OCONEE UNIT 3 NOTICE OF UNUSUAL EVENT UPDATE Discussion: This morning report supplements information regarding a Notice of Unusual Event (NOUE) which occurred on Oconee Unit 3 on December 27, 1999 (Event Notification 36543). The NOUE was terminated at 8:42 p.m., on December 27, 1999, following isolation of reactor coolant system letdown. Isolating letdown resulted in an increasing pressurizer level. At 9:01 p.m., pressurizer level exceeded the high level limit specified in Technical Specification (TS) 3.4.9. The licensee isolated and unisolated letdown, and entered and exited the pressurizer level TS, for several hours while controlling pressurizer level. After establishing an alternate letdown flowpath, the licensee exited the pressurizer level TS for the final time at 2:23 a.m. on December 28. Manual control of pressurizer level has been maintained satisfactorily since that time. The diversion of reactor coolant system water to the bleed holdup tank has stopped. Power level was reduced first to 50 percent power and then to 35 percent during this event. Licensee troubleshooting identified a failure in the mechanical coupling between the actuator and the letdown bypass valve (3HP-14) stem. The licensee is currently fabricating a replacement component for the valve and intends to install this component with the unit online later today. Regional Action: The residents are following this issue. Contact: Charles R. Ogle (404)562-4510 _
Page Last Reviewed/Updated Wednesday, March 24, 2021
Page Last Reviewed/Updated Wednesday, March 24, 2021