Event Notification Report for November 24, 2011
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
11/23/2011 - 11/24/2011
EVENT NUMBERS
47476
!!!!! THIS EVENT HAS BEEN RETRACTED !!!!!
!!!!! THIS EVENT HAS BEEN RETRACTED !!!!!
Power Reactor
Event Number: 47476
Facility: KEWAUNEE
Region: 3 State: WI
Unit: [1] [] []
RX Type: [1] W-2-LP
NRC Notified By: MIKE TERRY
HQ OPS Officer: JOHN KNOKE
Region: 3 State: WI
Unit: [1] [] []
RX Type: [1] W-2-LP
NRC Notified By: MIKE TERRY
HQ OPS Officer: JOHN KNOKE
Notification Date: 11/24/2011
Notification Time: 11:17 [ET]
Event Date: 11/24/2011
Event Time: 03:15 [CST]
Last Update Date: 01/18/2012
Notification Time: 11:17 [ET]
Event Date: 11/24/2011
Event Time: 03:15 [CST]
Last Update Date: 01/18/2012
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(ii)(B) - UNANALYZED CONDITION
10 CFR Section:
50.72(b)(3)(ii)(B) - UNANALYZED CONDITION
Person (Organization):
JULIO LARA (R3DO)
JULIO LARA (R3DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | N | Y | 100 | Power Operation | 100 | Power Operation |
EMERGENCY 4160 VOLT AC BUSSES DECLARED INOPERABLE
"On Thursday, November 24, 2011, at 0315 CST, with the reactor at 100% steady state thermal power, Kewaunee Power Station declared both emergency 4160 Volt AC busses inoperable due to voltages being high outside of the procedurally directed voltage band. As a result, in accordance with Technical Specification 3.8.9, Distribution Sources - Operating, Kewaunee entered Technical Specification LCO 3.0.3 to, within 1 hour, initiate shutdown of the unit. At 0410 [CST], per management direction, the load tap changers for the supply transformers were adjusted to reduce the emergency bus voltages to within their procedural operating band. At this time, both emergency busses were declared Operable and LCO 3.0.3 was exited. Minimum required accident voltages were met at all times.
"The NRC Resident Inspector has been notified."
* * * RETRACTED AT 1515 EST ON 01/18/12 FROM RICHARD REPSHAS TO S. SANDIN * * *
"On November 24, 2011, EN # 47476 provided notification that both emergency 4160 Volt AC busses were inoperable based on voltages being high outside of a procedurally directed voltage band.
"Subsequent investigation and analysis determined that unnecessary conservatisms were used in the development of the voltage values used in procedure, OSP-MISC-002, Electrical Power System Weekly Surveillance Test. Review of the actual voltages present during the event determined that the voltages did not exceed the required values to support bus operability.
"Therefore, the busses remained operable and this condition did not meet the reportability criteria identified in 10 CFR 50.72. As a result, the notification made on 11/24/2011 is hereby retracted."
The licensee informed the NRC Resident Inspector.
"On Thursday, November 24, 2011, at 0315 CST, with the reactor at 100% steady state thermal power, Kewaunee Power Station declared both emergency 4160 Volt AC busses inoperable due to voltages being high outside of the procedurally directed voltage band. As a result, in accordance with Technical Specification 3.8.9, Distribution Sources - Operating, Kewaunee entered Technical Specification LCO 3.0.3 to, within 1 hour, initiate shutdown of the unit. At 0410 [CST], per management direction, the load tap changers for the supply transformers were adjusted to reduce the emergency bus voltages to within their procedural operating band. At this time, both emergency busses were declared Operable and LCO 3.0.3 was exited. Minimum required accident voltages were met at all times.
"The NRC Resident Inspector has been notified."
* * * RETRACTED AT 1515 EST ON 01/18/12 FROM RICHARD REPSHAS TO S. SANDIN * * *
"On November 24, 2011, EN # 47476 provided notification that both emergency 4160 Volt AC busses were inoperable based on voltages being high outside of a procedurally directed voltage band.
"Subsequent investigation and analysis determined that unnecessary conservatisms were used in the development of the voltage values used in procedure, OSP-MISC-002, Electrical Power System Weekly Surveillance Test. Review of the actual voltages present during the event determined that the voltages did not exceed the required values to support bus operability.
"Therefore, the busses remained operable and this condition did not meet the reportability criteria identified in 10 CFR 50.72. As a result, the notification made on 11/24/2011 is hereby retracted."
The licensee informed the NRC Resident Inspector.