Event Notification Report for April 23, 2011
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
04/22/2011 - 04/23/2011
Power Reactor
Event Number: 46977
Facility: COLUMBIA GENERATING STATION
Region: 4 State: WA
Unit: [2] [] []
RX Type: [2] GE-5
NRC Notified By: RICK GARCIA
HQ OPS Officer: STEVE SANDIN
Region: 4 State: WA
Unit: [2] [] []
RX Type: [2] GE-5
NRC Notified By: RICK GARCIA
HQ OPS Officer: STEVE SANDIN
Notification Date: 06/21/2011
Notification Time: 18:40 [ET]
Event Date: 04/23/2011
Event Time: 08:14 [PDT]
Last Update Date: 06/21/2011
Notification Time: 18:40 [ET]
Event Date: 04/23/2011
Event Time: 08:14 [PDT]
Last Update Date: 06/21/2011
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):
RICK DEESE (R4DO)
RICK DEESE (R4DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 2 | N | N | 0 | Refueling | 0 | Refueling |
INVALID PRIMARY CONTAINMENT ISOLATION SYSTEM ACTUATION DUE TO UNRECOGNIZED DESIGN CONFLICT
"This event is reportable under 10 CFR 50.73(a)(2)(iv)(A) as an automatic actuation of general containment isolation signals affecting containment isolation valves in more than one system. This 60-day telephone notification is being made in accordance with 10 CFR 50.73(a)(1) for invalid actuations reported under 10 CFR 50.73(a)(2)(iv)(A). This actuation was invalid since it was caused by maintenance activities and not by any actual plant condition warranting containment isolation.
"On April 23, 2011, at 0814 hours, during implementation of a clearance order for ongoing work, Reactor Protection System (RPS) Bus A was transferred from the normal to alternate power supply. The power transfer functions as a break before make, and the momentary loss of power caused an unexpected actuation of the Groups 3 and 4 outboard containment isolation valves. Outboard isolations occurred in the reactor building drain and ventilation systems, and reactor closed cooling systems. Control room emergency ventilation and standby gas treatment systems also started. All systems functioned as designed, excluding those components that were already removed from service. Following the event, the RPS Bus A was re-energized and the plant was restored to normal operating condition for the current configuration per plant procedures.
"The unexpected actuation was due to a latent design conflict between a new design modification and existing equipment that was not discovered until during the implementation phase of the modification. The subsequent investigation cited inadequate review and engagement in the design process by station personnel of the vendor supplied design change modification package as the cause. As part of the implementation of the modification package an interposing relay was introduced into the Nuclear Steam Supply Shutoff System (NSSSS) logic circuit. The work for this modification was performed on the two days prior to this event, April 21st and 22nd. The new design was such that the source of power for the added relay was the same power supply which supplied the alternate logic channel. The resulting condition created a scenario where loss of the RPS-A power supply would complete both halves of the NSSSS outboard trip logic. The design has been revised such that loss of RPS-A or RPS-B power supply will not result in loss of both halves of the NSSSS trip logic circuit. Planned corrective actions will enhance procedures to ensure key design parameters and performance objectives are established early in the design process.
"There were no actual safety consequences associated with this event since all affected equipment responded as designed. The NRC Resident Inspectors have been notified."
"This event is reportable under 10 CFR 50.73(a)(2)(iv)(A) as an automatic actuation of general containment isolation signals affecting containment isolation valves in more than one system. This 60-day telephone notification is being made in accordance with 10 CFR 50.73(a)(1) for invalid actuations reported under 10 CFR 50.73(a)(2)(iv)(A). This actuation was invalid since it was caused by maintenance activities and not by any actual plant condition warranting containment isolation.
"On April 23, 2011, at 0814 hours, during implementation of a clearance order for ongoing work, Reactor Protection System (RPS) Bus A was transferred from the normal to alternate power supply. The power transfer functions as a break before make, and the momentary loss of power caused an unexpected actuation of the Groups 3 and 4 outboard containment isolation valves. Outboard isolations occurred in the reactor building drain and ventilation systems, and reactor closed cooling systems. Control room emergency ventilation and standby gas treatment systems also started. All systems functioned as designed, excluding those components that were already removed from service. Following the event, the RPS Bus A was re-energized and the plant was restored to normal operating condition for the current configuration per plant procedures.
"The unexpected actuation was due to a latent design conflict between a new design modification and existing equipment that was not discovered until during the implementation phase of the modification. The subsequent investigation cited inadequate review and engagement in the design process by station personnel of the vendor supplied design change modification package as the cause. As part of the implementation of the modification package an interposing relay was introduced into the Nuclear Steam Supply Shutoff System (NSSSS) logic circuit. The work for this modification was performed on the two days prior to this event, April 21st and 22nd. The new design was such that the source of power for the added relay was the same power supply which supplied the alternate logic channel. The resulting condition created a scenario where loss of the RPS-A power supply would complete both halves of the NSSSS outboard trip logic. The design has been revised such that loss of RPS-A or RPS-B power supply will not result in loss of both halves of the NSSSS trip logic circuit. Planned corrective actions will enhance procedures to ensure key design parameters and performance objectives are established early in the design process.
"There were no actual safety consequences associated with this event since all affected equipment responded as designed. The NRC Resident Inspectors have been notified."
Power Reactor
Event Number: 46780
Facility: CATAWBA
Region: 2 State: SC
Unit: [1] [] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: DONALD WISNEIWSKI
HQ OPS Officer: MARK ABRAMOVITZ
Region: 2 State: SC
Unit: [1] [] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: DONALD WISNEIWSKI
HQ OPS Officer: MARK ABRAMOVITZ
Notification Date: 04/23/2011
Notification Time: 12:37 [ET]
Event Date: 04/23/2011
Event Time: 09:21 [EDT]
Last Update Date: 04/23/2011
Notification Time: 12:37 [ET]
Event Date: 04/23/2011
Event Time: 09:21 [EDT]
Last Update Date: 04/23/2011
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(iv)(A) - VALID SPECIF SYS ACTUATION
10 CFR Section:
50.72(b)(3)(iv)(A) - VALID SPECIF SYS ACTUATION
Person (Organization):
JONATHAN BARTLEY (R2DO)
JONATHAN BARTLEY (R2DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | N | N | 0 | Hot Shutdown | 0 | Hot Shutdown |
VALID AUXILIARY FEEDWATER PUMP START WHILE COOLING DOWN REACTOR
"At 0921 [EDT] on 4/23/11, CNS Unit-1 received an auxiliary feedwater pump auto start due to low-low level in the 1B steam generator. The 1A auxiliary feedwater pump started and restored steam generator level to the normal operating band."
A cooldown was in progress at the time of the event and the tagout isolated feedwater flow to the 1B steam generator.
The licensee notified the NRC Resident Inspector. The states of North and South Carolina, and York, Gaston, and Mecklenburg Counties will be notified.
"At 0921 [EDT] on 4/23/11, CNS Unit-1 received an auxiliary feedwater pump auto start due to low-low level in the 1B steam generator. The 1A auxiliary feedwater pump started and restored steam generator level to the normal operating band."
A cooldown was in progress at the time of the event and the tagout isolated feedwater flow to the 1B steam generator.
The licensee notified the NRC Resident Inspector. The states of North and South Carolina, and York, Gaston, and Mecklenburg Counties will be notified.
Fuel Cycle Facility
Event Number: 46781
Facility: HONEYWELL INTERNATIONAL, INC.
Region: 2 State: IL
Unit: [] [] []
RX Type: URANIUM HEXAFLUORIDE PRODUCTION
NRC Notified By: BOB STOKES
HQ OPS Officer: MARK ABRAMOVITZ
Region: 2 State: IL
Unit: [] [] []
RX Type: URANIUM HEXAFLUORIDE PRODUCTION
NRC Notified By: BOB STOKES
HQ OPS Officer: MARK ABRAMOVITZ
Notification Date: 04/23/2011
Notification Time: 22:08 [ET]
Event Date: 04/23/2011
Event Time: 17:00 [CDT]
Last Update Date: 04/23/2011
Notification Time: 22:08 [ET]
Event Date: 04/23/2011
Event Time: 17:00 [CDT]
Last Update Date: 04/23/2011
Emergency Class: NON EMERGENCY
10 CFR Section:
40.60(b)(2) - SAFETY EQUIPMENT FAILURE
10 CFR Section:
40.60(b)(2) - SAFETY EQUIPMENT FAILURE
Person (Organization):
JONATHAN BARTLEY (R2DO)
EARL EASTON (NMSS)
JONATHAN BARTLEY (R2DO)
EARL EASTON (NMSS)
LOSS OF POWER SHUTS DOWN AIR MONITORING VACUUM PUMPS
"The air monitoring vacuum pumps were disabled for approximately 3 hours. A severe weather windstorm blew down an electrical power pole inside the plant property at 1700 CDT. Because of the electrical issue, it took approximately 3 hours to reestablish cooling water to the vacuum pumps. These pumps provide vacuum for the stack monitoring and personnel area monitoring systems in the Feed Materials Building. The pumps were restored to service at approximately 2000 CDT."
There was no damage, no release, and no exposure from this event.
The licensee notified the Fuel Facility Inspector (Hartland) in Region-2.
"The air monitoring vacuum pumps were disabled for approximately 3 hours. A severe weather windstorm blew down an electrical power pole inside the plant property at 1700 CDT. Because of the electrical issue, it took approximately 3 hours to reestablish cooling water to the vacuum pumps. These pumps provide vacuum for the stack monitoring and personnel area monitoring systems in the Feed Materials Building. The pumps were restored to service at approximately 2000 CDT."
There was no damage, no release, and no exposure from this event.
The licensee notified the Fuel Facility Inspector (Hartland) in Region-2.