Event Notification Report for December 25, 2006
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
12/24/2006 - 12/25/2006
EVENT NUMBERS
43062
Power Reactor
Event Number: 43062
Facility: BRUNSWICK
Region: 2 State: NC
Unit: [] [2] []
RX Type: [1] GE-4,[2] GE-4
NRC Notified By: STEVE GORDY
HQ OPS Officer: JOHN KNOKE
Region: 2 State: NC
Unit: [] [2] []
RX Type: [1] GE-4,[2] GE-4
NRC Notified By: STEVE GORDY
HQ OPS Officer: JOHN KNOKE
Notification Date: 12/25/2006
Notification Time: 09:27 [ET]
Event Date: 12/25/2006
Event Time: 05:39 [EST]
Last Update Date: 12/25/2006
Notification Time: 09:27 [ET]
Event Date: 12/25/2006
Event Time: 05:39 [EST]
Last Update Date: 12/25/2006
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(2)(iv)(A) - ECCS INJECTION 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)(A) - ECCS INJECTION 50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL 50.72(b)(3)(iv)(A) - VALID SPECIF SYS ACTUATION
Person (Organization):
JOEL MUNDAY (R2)
JOEL MUNDAY (R2)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 2 | A/R | Y | 64 | Power Operation | 0 | Hot Shutdown |
REACTOR SCRAM DUE TO TRIP FROM NEUTRON MONITORING SYSTEM
"On 12/25/06 at approximately 05:39 an automatic reactor scram occurred on Brunswick Unit 2. The Reactor Protection System (RPS) actuated on Neutron Monitoring System (APRM/OPRM) trip for APRM 2 and 4. All control rods properly inserted when the scram occurred from the RPS signal. Reactor water level reached low level 1 (LL1) and low level 2 (LL2) as a result of the scram. The LL1 signal causes a Group 2 (floor and equipment drain isolation valves), Group 6 (monitoring and sampling isolation valves) and Group 8 (shutdown cooling isolation valves) isolation signal. The LL1 isolations occurred as designed. The LL2 [signal] causes a Reactor Core Isolation Cooling (RCIC) system actuation, High Pressure Coolant Injection (HPCI) system actuation, Group 3 (reactor water cleanup valves) isolation signal, a secondary containment isolation signal, a Standby Gas Treatment (SBGT) initiation signal, a Control Room Emergency Ventilation (CREV) initiation signal, Reactor Recirculation Pump trip and an Alternate Rod Insertion (ARI) actuation signal. The low level 2 condition was reached momentarily and did not affect all instruments due to calibration differences. Initial assessment concludes that the appropriate LL2 isolations and actuations occurred as designed. Further evaluation of LL2 isolation and actuations will be conducted. The RCIC system actuation resulted in injection into the reactor as designed. The HPCI system actuated but did not inject because reactor water level was recovered. The plant is in a stable condition. An investigation is in progress to determine the cause of the Neutron Monitoring System trip."
RCIC started momentarily and then was secured. Reactor water level being maintained via normal feedwater system. Decay heat being removed through the bypass valves. Normal electrical lineup for shutdown. EDGs available. Unit 1 not affected by this transient.
The licensee notified the NRC Resident Inspector.
"On 12/25/06 at approximately 05:39 an automatic reactor scram occurred on Brunswick Unit 2. The Reactor Protection System (RPS) actuated on Neutron Monitoring System (APRM/OPRM) trip for APRM 2 and 4. All control rods properly inserted when the scram occurred from the RPS signal. Reactor water level reached low level 1 (LL1) and low level 2 (LL2) as a result of the scram. The LL1 signal causes a Group 2 (floor and equipment drain isolation valves), Group 6 (monitoring and sampling isolation valves) and Group 8 (shutdown cooling isolation valves) isolation signal. The LL1 isolations occurred as designed. The LL2 [signal] causes a Reactor Core Isolation Cooling (RCIC) system actuation, High Pressure Coolant Injection (HPCI) system actuation, Group 3 (reactor water cleanup valves) isolation signal, a secondary containment isolation signal, a Standby Gas Treatment (SBGT) initiation signal, a Control Room Emergency Ventilation (CREV) initiation signal, Reactor Recirculation Pump trip and an Alternate Rod Insertion (ARI) actuation signal. The low level 2 condition was reached momentarily and did not affect all instruments due to calibration differences. Initial assessment concludes that the appropriate LL2 isolations and actuations occurred as designed. Further evaluation of LL2 isolation and actuations will be conducted. The RCIC system actuation resulted in injection into the reactor as designed. The HPCI system actuated but did not inject because reactor water level was recovered. The plant is in a stable condition. An investigation is in progress to determine the cause of the Neutron Monitoring System trip."
RCIC started momentarily and then was secured. Reactor water level being maintained via normal feedwater system. Decay heat being removed through the bypass valves. Normal electrical lineup for shutdown. EDGs available. Unit 1 not affected by this transient.
The licensee notified the NRC Resident Inspector.