Event Notification Report for November 14, 2010
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
11/13/2010 - 11/14/2010
Power Reactor
Event Number: 46418
Facility: WATTS BAR
Region: 2 State: TN
Unit: [1] [] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: SHAWN HAFEN
HQ OPS Officer: HOWIE CROUCH
Region: 2 State: TN
Unit: [1] [] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: SHAWN HAFEN
HQ OPS Officer: HOWIE CROUCH
Notification Date: 11/14/2010
Notification Time: 09:05 [ET]
Event Date: 11/14/2010
Event Time: 06:52 [EST]
Last Update Date: 11/14/2010
Notification Time: 09:05 [ET]
Event Date: 11/14/2010
Event Time: 06:52 [EST]
Last Update Date: 11/14/2010
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):
ALAN BLAMEY (R2DO)
ALAN BLAMEY (R2DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | M/R | Y | 100 | Power Operation | 0 | Hot Standby |
MANUAL REACTOR TRIP DUE TO LOSS OF COOLING TO THE 'A' PHASE MAIN BANK TRANSFORMER
"At 0617 [hrs. EST], Watts Bar experienced a failure of the cooling system to the 'A' phase Main Bank Transformer. Due to rising oil temperatures on the 'A' phase Main Bank Transformer, the reactor was manually tripped at 0652 hrs. All systems responded as designed with no issues."
All rods inserted during the trip. There were no primary or secondary relief valves that lifted during the transient. The grid is stable and the plant is in a normal shutdown electrical line-up. The reactor is at normal pressure and temperature with decay heat being removed via the steam dumps to condenser with auxiliary feedwater providing steam generator make-up. The cause of the loss of cooling to the 'A' phase Main Bank Transformer was the failure of a control power transformer that supplies the Main Bank Transformer cooling system components.
The licensee has notified the NRC Resident Inspector.
"At 0617 [hrs. EST], Watts Bar experienced a failure of the cooling system to the 'A' phase Main Bank Transformer. Due to rising oil temperatures on the 'A' phase Main Bank Transformer, the reactor was manually tripped at 0652 hrs. All systems responded as designed with no issues."
All rods inserted during the trip. There were no primary or secondary relief valves that lifted during the transient. The grid is stable and the plant is in a normal shutdown electrical line-up. The reactor is at normal pressure and temperature with decay heat being removed via the steam dumps to condenser with auxiliary feedwater providing steam generator make-up. The cause of the loss of cooling to the 'A' phase Main Bank Transformer was the failure of a control power transformer that supplies the Main Bank Transformer cooling system components.
The licensee has notified the NRC Resident Inspector.
Power Reactor
Event Number: 46504
Facility: SEQUOYAH
Region: 2 State: TN
Unit: [1] [] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: DENNIS DIMOPOULOS
HQ OPS Officer: JOHN KNOKE
Region: 2 State: TN
Unit: [1] [] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: DENNIS DIMOPOULOS
HQ OPS Officer: JOHN KNOKE
Notification Date: 12/22/2010
Notification Time: 21:33 [ET]
Event Date: 11/14/2010
Event Time: 05:09 [EST]
Last Update Date: 12/22/2010
Notification Time: 21:33 [ET]
Event Date: 11/14/2010
Event Time: 05:09 [EST]
Last Update Date: 12/22/2010
Emergency Class: NON EMERGENCY
10 CFR Section:
50.73(a)(1) - INVALID SPECIF SYSTEM ACTUATION
10 CFR Section:
50.73(a)(1) - INVALID SPECIF SYSTEM ACTUATION
Person (Organization):
DAVID AYRES (R2DO)
DAVID AYRES (R2DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | N | N | 0 | Hot Standby | 0 | Hot Standby |
INVALID ACTUATION OF TURBINE DRIVEN AUXILIARY FEEDWATER PUMP
"This report is a 60-day telephone notification in lieu of written LER being made under 10CFR50.73(a)(2)(iv)(A) and 10CFR50.73(a)(1). The event was an invalid actuation of the Unit 1 turbine driven auxiliary feedwater (TDAFW) pump.
"At 0509 EST on 11/14/2010, during testing of the 1B main feedwater pump (MFP), the TDAFW pump started and the motor driven auxiliary feedwater (MDAFW) valves received a signal to go to automatic control. An investigation determined that during previous testing of the 1A MFP, the 1A MFP trip relay (RTT-1) remained stuck in the trip condition. The stuck relay on the 1A MFP and the trip test on 1B MFP made up the logic for a TDAFW and MDAFW start from both MFPs tripped signal. The 1A MFP trip relay was replaced.
"The Unit 1A and B train MDAFW and TDAFW system received the actuation signal. The 1A and 1B MDAFW pumps were already in service at the time for Mode 3 operation. Actual plant conditions did not exist that required an automatic start of the auxiliary feedwater system. Therefore, this actuation was invalid. A complete train actuation occurred and the auxiliary feedwater system functioned successfully."
The licensee has notified the NRC Resident Inspector.
"This report is a 60-day telephone notification in lieu of written LER being made under 10CFR50.73(a)(2)(iv)(A) and 10CFR50.73(a)(1). The event was an invalid actuation of the Unit 1 turbine driven auxiliary feedwater (TDAFW) pump.
"At 0509 EST on 11/14/2010, during testing of the 1B main feedwater pump (MFP), the TDAFW pump started and the motor driven auxiliary feedwater (MDAFW) valves received a signal to go to automatic control. An investigation determined that during previous testing of the 1A MFP, the 1A MFP trip relay (RTT-1) remained stuck in the trip condition. The stuck relay on the 1A MFP and the trip test on 1B MFP made up the logic for a TDAFW and MDAFW start from both MFPs tripped signal. The 1A MFP trip relay was replaced.
"The Unit 1A and B train MDAFW and TDAFW system received the actuation signal. The 1A and 1B MDAFW pumps were already in service at the time for Mode 3 operation. Actual plant conditions did not exist that required an automatic start of the auxiliary feedwater system. Therefore, this actuation was invalid. A complete train actuation occurred and the auxiliary feedwater system functioned successfully."
The licensee has notified the NRC Resident Inspector.