Event Notification Report for May 19, 2001
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
05/18/2001 - 05/19/2001
Power Reactor
Event Number: 38012
Facility: BRAIDWOOD
Region: 3 State: IL
Unit: [] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: SHEAR
HQ OPS Officer: JOHN MacKINNON
Region: 3 State: IL
Unit: [] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: SHEAR
HQ OPS Officer: JOHN MacKINNON
Notification Date: 05/19/2001
Notification Time: 07:46 [ET]
Event Date: 05/19/2001
Event Time: 04:06 [CDT]
Last Update Date: 05/19/2001
Notification Time: 07:46 [ET]
Event Date: 05/19/2001
Event Time: 04:06 [CDT]
Last Update Date: 05/19/2001
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):
GARY SHEAR (R3)
JOHN ZWOLINSKI (NRR)
NADER MAMISH (IRO)
GARY SHEAR (R3)
JOHN ZWOLINSKI (NRR)
NADER MAMISH (IRO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 2 | A/R | Y | 100 | Power Operation | 0 | Hot Standby |
UNIT 2 ON NATURAL CIRCULATION AFTER A AUTOMATIC REACTOR TRIP.
Unit 2 reactor coolant pump low flow reactor trip occurred due to a loss of a non-vital 6.9kV bus. The cause of the trip was human error while manipulating electrical plant equipment for planned work. The trip caused a loss of all non-ESF power to Unit 2. All safety systems actuated as required (all rods fully inserted into the core). The plant is currently in Mode 3 (Hot Standby) on natural circulation. No radioactive releases occurred.
The licensee took their system Auxiliary Transformer out of service for planned work. The Auxiliary Transformer is the normal offsite power supply to Unit 2 ESF (vital) buses. Unit 2 was cross tied to Unit 1 offsite power supply to supply power to the Unit 2 vital buses while Unit 2 Auxiliary Transformer was out of service. While preparing to restore the auxiliary transformer to service personnel were sent to the 6.9kV non-ESF switchgear room to pull the potential transformer fuses. Instead they pulled the bus potential transformer fuses which resulted in a loss of the bus which in turn tripped the reactor coolant pumps. The bus potential transformer fuses are located in a drawer just above the potential transformer fuses drawer. Once the drawer is opened the fuses come out of their holder.
After the reactor trip the diesel driven and the motor driven auxiliary feedwater pumps started. The diesel driven auxiliary feedwater pump was secured and now the motor driven auxiliary feedwater pump is supplying water to maintain proper steam generator water levels. The steam generator atmospheric valves are being used to maintain the plant in Hot Standby, no primary to secondary leakage. Both emergency diesel generators were manually started and they are supplying electrical power to the vital buses and power to two non-vital buses. The Unit 2 cross tie to Unit 1 offsite power supply was de-energized after Unit 2 emergency diesel generators were brought into service. If the emergency diesel generators are loss it will take less than 5 minutes to return Unit 1 offsite power back to Unit 2 ESF (vital) buses. All emergency core cooling systems are fully operable and pressurizer water level is within its proper range. Offsite power should be restored in about 4 hours.
Unit 1 is at 100% power.
The NRC Resident Inspector was notified of this event by the licensee.
* * * UPDATE ON 05/19/01 AT 1127 ET BY CAROL ROCHA TAKEN BY MACKINNON * * *
The purpose of this update is to notify the NRC within 8 hours of a valid actuation of the Unit 2 Auxiliary Feedwater System. Both trains of Auxiliary Feedwater actuated, as expected, on a Low-2 Steam Generator Level Signal.
Division 11 4 kV offsite power was restored to the vital buses via 242-1 (at 0901CT) and 242-2 (at 0906CT). 6.9kV non -vital power was restored at 0727 CT and 0726CT. The emergency diesel generators "2A" & "2B" were secured at 0907CT and 0929CT respectively. A Reactor Coolant Pump was started and forced flow was restored to the reactor coolant system. R3DO (Shear) & NRR EO (Zwolinski) notified.
The NRC Resident Inspector was notified of this update by the licensee.
Unit 2 reactor coolant pump low flow reactor trip occurred due to a loss of a non-vital 6.9kV bus. The cause of the trip was human error while manipulating electrical plant equipment for planned work. The trip caused a loss of all non-ESF power to Unit 2. All safety systems actuated as required (all rods fully inserted into the core). The plant is currently in Mode 3 (Hot Standby) on natural circulation. No radioactive releases occurred.
The licensee took their system Auxiliary Transformer out of service for planned work. The Auxiliary Transformer is the normal offsite power supply to Unit 2 ESF (vital) buses. Unit 2 was cross tied to Unit 1 offsite power supply to supply power to the Unit 2 vital buses while Unit 2 Auxiliary Transformer was out of service. While preparing to restore the auxiliary transformer to service personnel were sent to the 6.9kV non-ESF switchgear room to pull the potential transformer fuses. Instead they pulled the bus potential transformer fuses which resulted in a loss of the bus which in turn tripped the reactor coolant pumps. The bus potential transformer fuses are located in a drawer just above the potential transformer fuses drawer. Once the drawer is opened the fuses come out of their holder.
After the reactor trip the diesel driven and the motor driven auxiliary feedwater pumps started. The diesel driven auxiliary feedwater pump was secured and now the motor driven auxiliary feedwater pump is supplying water to maintain proper steam generator water levels. The steam generator atmospheric valves are being used to maintain the plant in Hot Standby, no primary to secondary leakage. Both emergency diesel generators were manually started and they are supplying electrical power to the vital buses and power to two non-vital buses. The Unit 2 cross tie to Unit 1 offsite power supply was de-energized after Unit 2 emergency diesel generators were brought into service. If the emergency diesel generators are loss it will take less than 5 minutes to return Unit 1 offsite power back to Unit 2 ESF (vital) buses. All emergency core cooling systems are fully operable and pressurizer water level is within its proper range. Offsite power should be restored in about 4 hours.
Unit 1 is at 100% power.
The NRC Resident Inspector was notified of this event by the licensee.
* * * UPDATE ON 05/19/01 AT 1127 ET BY CAROL ROCHA TAKEN BY MACKINNON * * *
The purpose of this update is to notify the NRC within 8 hours of a valid actuation of the Unit 2 Auxiliary Feedwater System. Both trains of Auxiliary Feedwater actuated, as expected, on a Low-2 Steam Generator Level Signal.
Division 11 4 kV offsite power was restored to the vital buses via 242-1 (at 0901CT) and 242-2 (at 0906CT). 6.9kV non -vital power was restored at 0727 CT and 0726CT. The emergency diesel generators "2A" & "2B" were secured at 0907CT and 0929CT respectively. A Reactor Coolant Pump was started and forced flow was restored to the reactor coolant system. R3DO (Shear) & NRR EO (Zwolinski) notified.
The NRC Resident Inspector was notified of this update by the licensee.
Power Reactor
Event Number: 38013
Facility: PALO VERDE
Region: 4 State: AZ
Unit: [] [] [3]
RX Type: [1] CE,[2] CE,[3] CE
NRC Notified By: STROUD
HQ OPS Officer: JOHN MacKINNON
Region: 4 State: AZ
Unit: [] [] [3]
RX Type: [1] CE,[2] CE,[3] CE
NRC Notified By: STROUD
HQ OPS Officer: JOHN MacKINNON
Notification Date: 05/19/2001
Notification Time: 09:52 [ET]
Event Date: 05/19/2001
Event Time: 03:06 [MST]
Last Update Date: 05/19/2001
Notification Time: 09:52 [ET]
Event Date: 05/19/2001
Event Time: 03:06 [MST]
Last Update Date: 05/19/2001
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL
10 CFR Section:
50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL
Person (Organization):
BLAIR SPITZBERG (R4)
BLAIR SPITZBERG (R4)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 3 | A/R | Y | 19 | Power Operation | 0 | Hot Standby |
On May 19, 2001, at approximately 0306 MST Palo Verde Unit 3 experienced a reactor trip (reactor protection system actuation) from 19% rated thermal power due axial shape index trips on all four channels of the core protection calculators.(CPCs). All control element assemblies inserted and plant equipment response was normal and as expected.
Prior to the plant trip, Unit 3 had reduced power to 19% and had stabilized as part of pre-planned activities to perform maintenance on the main turbine, which had been taken offline at 0252 MST. The unit was at normal temperature and pressure prior to the trip.
After the plant rip, control room staff entered the emergency operating procedures and diagnosed the event as an uncomplicated reactor trip with no emergency classifications being required. The primary plant was stabilized in Mode 3 in forced circulation with both steam generators used for heat removal.
Unit 3 is stable at normal operating temperature and pressure in Mode 3. Other than the reactor protection system actuation no other engineered safety feature actuations occurred and none were required. The event did not result in any challenges to the fission product barrier or result in any releases of radioactive materials. There were no adverse safety consequences or implications as a result of this event. The event did not adversely affect the safe operation of the plant or health and safety of the public.
The NRC Resident Inspector was notified of this event by the licensee.
Prior to the plant trip, Unit 3 had reduced power to 19% and had stabilized as part of pre-planned activities to perform maintenance on the main turbine, which had been taken offline at 0252 MST. The unit was at normal temperature and pressure prior to the trip.
After the plant rip, control room staff entered the emergency operating procedures and diagnosed the event as an uncomplicated reactor trip with no emergency classifications being required. The primary plant was stabilized in Mode 3 in forced circulation with both steam generators used for heat removal.
Unit 3 is stable at normal operating temperature and pressure in Mode 3. Other than the reactor protection system actuation no other engineered safety feature actuations occurred and none were required. The event did not result in any challenges to the fission product barrier or result in any releases of radioactive materials. There were no adverse safety consequences or implications as a result of this event. The event did not adversely affect the safe operation of the plant or health and safety of the public.
The NRC Resident Inspector was notified of this event by the licensee.