United States Nuclear Regulatory Commission - Protecting People and the Environment

Morning Report for July 29, 2004

Headquarters Daily Report

To top of page

REGION II

PLANT SHUTDOWN REQUIRED BY TECHNICAL SPECIFICATIONS - OCONEE UNITS 1,2, AND 3

Licensee/Facility:

DUKE ENERGY CORP.
Oconee 1, Oconee 2, Oconee 3
SENECA, South Carolina
Dockets: 05000269, 05000270, 05000287
[1] B&W-L-LP, [2] B&W-L-LP, [3] B&W-L-LP
License No:
Notification:

MR Number: 2-2004-0009
Date: 07/29/2004

Call from Licensee

Discussion:

This is an update to the 10 CFR 50.72 notification dated July 28, 2004, regarding loss of the switchyard (SWYD) 125 VDC battery chargers, which resulted in the initiation of a Technical Specification (TS) 3.0.3 required shutdown of all three Oconee units. Preliminary investigation indicates that rain water intrusion caused a fault in an AC power transfer switch, causing the loss of both AC sources to the switchyard 125 VDC battery chargers. The licensee promptly initiated additional actions to prevent a loss of offsite power.

The TS 3.0.3 required Unit shutdowns were terminated at approximately 12:05 p.m. after: (1) the fault was isolated; (2) both AC battery charger sources were restored; and (3) SWYD battery cell voltages were returned to their minimum TS required limits. The licensee is currently performing a root cause investigation. Information indicates that the emergency power systems remained operable during the incident.

Regional Action: The resident inspectors responded to the site and continue to monitor the licensee's recovery actions and investigation of the event. Region II plans to conduct additional detailed inspection of the licensee's activities and corrective actions.

Accession Numbers:

Accession No Accession Date
ML042110451 07/29/2004

Contacts:

Name Office Abbrev Phone No E-Mail
CARROLL, ROBERT E R2 (404) 562-4511 REC1@nrc.gov
Page Last Reviewed/Updated Thursday, March 29, 2012