The licensee experienced a
reactor trip to Units 1 & 2 due to loss of all offsite power. This anomaly was believed to be from an overcurrent condition in a relay, and limited to the Catawba
switchyard. The reactor tripped due to actuation of the
reactor protection system (
RPS), and all rods for both Units fully inserted as designed. The Unit 1 Pressurizer
PORV did lift momentarily. The decay heat is being released through the secondary
PORV's, and
steam generator level is being maintained with the
auxiliary feedwater system (
AFW). Presently, Units 1 & 2 are in
EAL 4.5.U.1 (Loss of Offsite Power to Essential Busses for greater than 15 minutes). The licensee indicated there are no
steam generator tube leaks in either unit. The licensee activated the
TSC at 15:50 EDT.
The licensee notified the NRC Resident Inspector, as well as State and local government.
- * * UPDATE FROM SI BILLENGER TO HUFFMAN AT 0152 EDT ON 5/21/06 * * *
The licensee terminated from the Unusual Event at 0140 EDT on 5/21/06 based on restoration of offsite power to all essential buses. The licensee is no longer in a Tech Spec cooldown LCO and both units have secured from further cooldown and have stabilized conditions in Mode 3. Both units are still on natural circulation with AFW cooling and decay heat removal through secondary PORVs.
The licensee will notify the NRC Resident Inspector. R2DO (Widmann),
NRR (Ross-Lee),
IRD (Blount),
FEMA (Kimbrell) and
DHS(York) have been notified
