Event Notification Report for October 25, 2006
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
10/24/2006 - 10/25/2006
EVENT NUMBERS
42933
Power Reactor
Event Number: 42933
Facility: ROBINSON
Region: 2 State: SC
Unit: [2] [] []
RX Type: [2] W-3-LP
NRC Notified By: GARRETT SANDERS
HQ OPS Officer: MARK ABRAMOVITZ
Region: 2 State: SC
Unit: [2] [] []
RX Type: [2] W-3-LP
NRC Notified By: GARRETT SANDERS
HQ OPS Officer: MARK ABRAMOVITZ
Notification Date: 10/25/2006
Notification Time: 06:32 [ET]
Event Date: 10/25/2006
Event Time: 02:48 [EDT]
Last Update Date: 10/25/2006
Notification Time: 06:32 [ET]
Event Date: 10/25/2006
Event Time: 02:48 [EDT]
Last Update Date: 10/25/2006
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL 50.72(b)(3)(iv)(A) - VALID SPECIF SYS ACTUATION
10 CFR Section:
50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL 50.72(b)(3)(iv)(A) - VALID SPECIF SYS ACTUATION
Person (Organization):
MIKE ERNSTES (R2)
MIKE ERNSTES (R2)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 2 | M/R | Y | 100 | Power Operation | 0 | Hot Standby |
MANUAL REACTOR TRIP AFTER A 100% LOAD REJECTION
"On October 25, 2006, at approximately 0247 hours (EDT), Main Control Room operators observed indications of a 100% load rejection and manually tripped the reactor at 0248 hours (EDT). During the event, Main Control Room operators received an alarm indicating that one or both pressurizer PORVs lifted briefly. The PORV(s) reclosed as designed. The reactor is currently stable in Mode 3.
"During the event, the steam generator PORVs briefly opened and re-closed, as expected. All controls rods indicated fully inserted following the reactor trip. The normal post-trip electrical lineup is providing power to the plant and the electrical system is stable at this time. Decay heat is currently being removed by use of the normal feedwater system and the condenser steam dumps.
"The cause of this event is under investigation. Follow-up notifications will be provided if important new information is obtained or plant conditions significantly change."
The licensee reported no steam generator tube leakage i.e. no radionuclide release during the brief lifting of the steam generator PORVs.
The licensee notified the NRC Resident Inspector.
* * * UPDATE ON 10/25/2006 AT 0941 FROM G. SANDERS TO M. ABRAMOVITZ * * *
"Subsequent to the initial notification, it has been determined that the automatic initiation of the Auxiliary Feedwater (AFW) System is also reportable under 10 CFR 50.72(b)(3)(iv)(A), Specified System Actuation. The AFW System automatically actuated as expected during the event in response to the secondary plant transient."
The licensee notified the NRC Resident Inspector.
Notified the R2DO (Ernestes).
"On October 25, 2006, at approximately 0247 hours (EDT), Main Control Room operators observed indications of a 100% load rejection and manually tripped the reactor at 0248 hours (EDT). During the event, Main Control Room operators received an alarm indicating that one or both pressurizer PORVs lifted briefly. The PORV(s) reclosed as designed. The reactor is currently stable in Mode 3.
"During the event, the steam generator PORVs briefly opened and re-closed, as expected. All controls rods indicated fully inserted following the reactor trip. The normal post-trip electrical lineup is providing power to the plant and the electrical system is stable at this time. Decay heat is currently being removed by use of the normal feedwater system and the condenser steam dumps.
"The cause of this event is under investigation. Follow-up notifications will be provided if important new information is obtained or plant conditions significantly change."
The licensee reported no steam generator tube leakage i.e. no radionuclide release during the brief lifting of the steam generator PORVs.
The licensee notified the NRC Resident Inspector.
* * * UPDATE ON 10/25/2006 AT 0941 FROM G. SANDERS TO M. ABRAMOVITZ * * *
"Subsequent to the initial notification, it has been determined that the automatic initiation of the Auxiliary Feedwater (AFW) System is also reportable under 10 CFR 50.72(b)(3)(iv)(A), Specified System Actuation. The AFW System automatically actuated as expected during the event in response to the secondary plant transient."
The licensee notified the NRC Resident Inspector.
Notified the R2DO (Ernestes).