| U.S. Nuclear Regulatory Commission
Operations Center Event Reports For
03/15/2007 - 03/16/2007 ** EVENT NUMBERS ** |
 | !!!!! THIS EVENT HAS BEEN RETRACTED. THIS EVENT HAS BEEN RETRACTED !!!!! | | Power Reactor | Event Number: 43157 | Facility: FT CALHOUN
Region: 4 State: NE
Unit: [1] [ ] [ ]
RX Type: [1] CE
NRC Notified By: ERICK MATZKE
HQ OPS Officer: STEVE SANDIN | Notification Date: 02/08/2007
Notification Time: 18:40 [ET]
Event Date: 02/08/2007
Event Time: 13:42 [CST]
Last Update Date: 03/15/2007 | Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(v)(B) - POT RHR INOP
| Person (Organization):
REBECCA NEASE (R4)
|
| Unit | SCRAM Code | RX CRIT | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode | | 1 | N | Y | 100 | Power Operation | 100 | Power Operation | Event Text RAW WATER PUMPS DECLARED INOPERABLE DUE TO A POTENTIAL FAILURE OF THE PUMP BREAKER LINKAGES
"On February 8, 2007 at 10:22 CST, Raw Water Pump AC-10C was declared inoperable when the pump breaker experienced a plunger linkage failure during a scheduled pump start for a scheduled rotation. Due to a similar failure of Raw Water Pump AC-10B two weeks earlier, a condition report was initiated for engineering to review the potential for a common failure mode. Engineering reviewed the number of cycles of the breakers for AC-10A and AC-10D both have greater than 1600 cycles. The breaker for AC-10B had over 1200 cycles at the time of its failure and AC-10C was over 1700 cycles. Based on the similar numbers of cycles, engineering has determined that continued operation of AC-10A and AC-10D without breaker failure could not he assured. All other safeguards associated breakers have been verified to have less than 1000 cycles and are not considered to be susceptible to breaker failure at this time. After discussion with engineering, Raw Water Pumps AC-10A and AC-10D were declared inoperable on February 8, 2007 at 13:42 CST based on the number of breaker cycles for these two components in relation to the two breakers that failed.
"With three Raw Water Pumps inoperable, Fort Calhoun Station entered Technical Specification 2.0.1 which requires the plant be placed in hot shutdown within six (6) hours. The potential for a common mode failure of the linkage in the 4160 VAC circuit breakers (ABB Combustion Engineering Model No. 5VKBR-250) could have prevented operation of the Raw Water Pumps to fulfill the required design function to remove residual heat during a design basis accident.
"At 15:22 CST, repairs were completed on Raw Water Pump AC-10C breaker and the pump was declared operable. At 15:34 CST, Technical Specification 2.0.1 was exited and Technical Specification 2.4(1)c, 7-day LCO was entered for the inoperability of Raw Water Pumps AC-10A and AC-10D. The repair of the breakers for AC-10A and AC-10D are scheduled for February 9, 2007."
The licensee informed the NRC Resident Inspector.
* * * UPDATE AT 1632 EST ON 2/12/07 FROM ERICK MATZKE TO S. SANDIN * * *
"This communication is meant to supplement the notification of February 8, 2007. The common mode failure of the linkage in the 4160V circuit breaker (ABB Combustion Engineering model number 5VKBR-250) could have prevented the operation of the raw water pumps as required by design. This could have resulted in the inability of the raw water system to remove residual heat during design basis accidents as required."
The licensee informed the NRC Resident Inspector. Notified R4DO (Smith).
* * * RETRACTION FROM MATZKE TO HUFFMAN AT 1447 EDT ON 3/15/07 * * *
"On February 3, 2007, (Event Number 43157) Fort Calhoun Station reported a condition that, at the time, was believed [to be] a possible common mode failure of the 4160V feeder breakers for the Raw Water (RW) System [redacted]. The circuit breakers for two of the four RW pump feeder breakers had failed. Investigation had determined that the failure mechanism was the same for the two failures. On February 8, it was not known if the other two RW pump breakers could fail by this same mechanism.
"The component that failed in the circuit breaker was an offset rod that transmitted operation of the circuit breaker to a set of auxiliary switches associated with the circuit breakers.
"The offset rods of the A and D RW pumps have subsequently been tested. Non destructive testing determined that the rods had no cracks. Destructive testing determined that the rods would not have failed for several hundred operations of the circuit breakers. As a result, the system was capable of performing its design safety function. Therefore, this event is not reportable under 10 CFR 50.72(b)(3)(B) as previously reported and EN 43157 is being retracted.
"While no verbal report criteria is applicable to this condition it is reportable as an LER under 10 CFR 50.73(a)(2)(vii)."
The licensee notified the NRC Resident Inspector. R4DO ( Shannon) notified. |
| Power Reactor | Event Number: 43239 | Facility: SUSQUEHANNA
Region: 1 State: PA
Unit: [ ] [2] [ ]
RX Type: [1] GE-4,[2] GE-4
NRC Notified By: RICH KLINEFELTER
HQ OPS Officer: BILL HUFFMAN | Notification Date: 03/14/2007
Notification Time: 22:06 [ET]
Event Date: 03/14/2007
Event Time: 23:00 [EDT]
Last Update Date: 03/15/2007 | Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(xiii) - LOSS COMM/ASMT/RESPONSE
| Person (Organization):
CHRIS HOTT (R1)
|
| Unit | SCRAM Code | RX CRIT | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode | | 2 | N | N | 0 | Refueling | 0 | Refueling | Event Text OUTAGE OF SPDS AND ERDS
"At 2300 hours, on 03/14/2007, the Unit 2 SPDS and ERDS system will be removed from service to support restoration activities from a planned maintenance outage on the power supply. The duration of work is expected to be approximately 20 hours. (Scheduled for completion at 1900 hours on 03/15/2007). During this time, Control Room indications and alternate methods will be available.
"Since the Unit 2 SPDS computer system will be unavailable for greater than 8 hours, this is considered a Loss of Emergency Assessment Capability and reportable under 10CFR50.72(b)(3)(xiii)."
The licensee notified the NRC Resident Inspector.
* * * UPDATE FROM HUFFORD TO HUFFMAN AT 2336 EDT ON 3/15/07 * * *
The SPDS and ERDS systems were returned to service at approximately 2230 EDT on 3/15/07. The licensee notified the NRC Resident Inspector. The R1DO (Hott) has been notified. |
| Power Reactor | Event Number: 43242 | Facility: HATCH
Region: 2 State: GA
Unit: [ ] [2] [ ]
RX Type: [1] GE-4,[2] GE-4
NRC Notified By: AL DEES
HQ OPS Officer: BILL HUFFMAN | Notification Date: 03/15/2007
Notification Time: 17:27 [ET]
Event Date: 03/15/2007
Event Time: 15:32 [EDT]
Last Update Date: 03/15/2007 | Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(v)(D) - ACCIDENT MITIGATION
| Person (Organization):
JAMES MOORMAN (R2)
|
| Unit | SCRAM Code | RX CRIT | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode | | 2 | N | Y | 1 | Startup | 1 | Startup | Event Text HPCI DECLARED INOPERABLE DURING STARTUP TESTING
"While performing the HPCI Pump Operability Test (34SV-E41-005-2), HPCI failed to start. Upon starting the HPCI Turbine, the turbine control valve failed to open. It was observed that alarm 'Oil Filler Differential Pressure High' was received (setpoint 11 psid). Local indication indicated that the differential pressure was 12 psid. Operators locally at the turbine did not observe any movement of the turbine shaft. The HPCI system was returned to standby and an investigation by Engineering and I & C has been initiated. [The licensee] suspects a problem with the EGR (Electronic Governor Module)."
The licensee will remain at the current power level and mode until the HPCI is repaired.
The licensee notified the NRC Resident Inspector. | |