Event Notification Report for May 22, 2011
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
05/21/2011 - 05/22/2011
Power Reactor
Event Number: 46872
Facility: BROWNS FERRY
Region: 2 State: AL
Unit: [] [] [3]
RX Type: [1] GE-4,[2] GE-4,[3] GE-4
NRC Notified By: TIM TAYLOR
HQ OPS Officer: JOE O'HARA
Region: 2 State: AL
Unit: [] [] [3]
RX Type: [1] GE-4,[2] GE-4,[3] GE-4
NRC Notified By: TIM TAYLOR
HQ OPS Officer: JOE O'HARA
Notification Date: 05/22/2011
Notification Time: 22:34 [ET]
Event Date: 05/22/2011
Event Time: 17:37 [CDT]
Last Update Date: 05/22/2011
Notification Time: 22:34 [ET]
Event Date: 05/22/2011
Event Time: 17:37 [CDT]
Last Update Date: 05/22/2011
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):
SCOTT SHAEFFER (R2DO)
SCOTT SHAEFFER (R2DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 3 | N | N | 0 | Cold Shutdown | 0 | Cold Shutdown |
VALID REACTOR PROTECTION SYSTEM (RPS) ACTUATION SIGNAL - SCRAM DISCHARGE VOLUME (SDV) HIGH WATER LEVEL
"At 1737 CDT on 05/22/2011, with BFN U3 [Browns Ferry Unit 3] in Mode 4, a valid RPS actuation signal was received by both channels of the RPS due to Scram Discharge Volume (SDV) High Water Level.
"At 1735, while performing IRM range 6 to 7 correlation, Instrument Maintenance technicians were measuring high voltage on IRM 'G' while reconnecting a high voltage cable. A spike occurred on IRM's 'C' and 'D' causing a full Reactor Scram. This IRM [Intermediate Range Monitor] Scram was not a valid actuation, the safety function had already been completed, and is not reportable. At 1737, after diagnosing the cause of the IRM Scram, operators reset the Scram signal and received a valid RPS Scram signal due to SDV High Water Level. Investigation is ongoing.
"This condition is reportable under 10CFR50.72(b)(3)(iv)(A) - A valid actuation of any of the systems named in 50.72(b)(3)(iv)(B).
"This is also reportable as 60 day written report IAW 10CFR 50.73(a)(2)(iv)(A).
"This event was entered into the licensee's Corrective Action Program as SR# 373366."
There are no compensatory measures or LCO's in effect for this event, and all EDG's and offsite power lines are operable. There was no increase in plant risk as a result of this event.
The NRC Resident Inspector has been notified.
"At 1737 CDT on 05/22/2011, with BFN U3 [Browns Ferry Unit 3] in Mode 4, a valid RPS actuation signal was received by both channels of the RPS due to Scram Discharge Volume (SDV) High Water Level.
"At 1735, while performing IRM range 6 to 7 correlation, Instrument Maintenance technicians were measuring high voltage on IRM 'G' while reconnecting a high voltage cable. A spike occurred on IRM's 'C' and 'D' causing a full Reactor Scram. This IRM [Intermediate Range Monitor] Scram was not a valid actuation, the safety function had already been completed, and is not reportable. At 1737, after diagnosing the cause of the IRM Scram, operators reset the Scram signal and received a valid RPS Scram signal due to SDV High Water Level. Investigation is ongoing.
"This condition is reportable under 10CFR50.72(b)(3)(iv)(A) - A valid actuation of any of the systems named in 50.72(b)(3)(iv)(B).
"This is also reportable as 60 day written report IAW 10CFR 50.73(a)(2)(iv)(A).
"This event was entered into the licensee's Corrective Action Program as SR# 373366."
There are no compensatory measures or LCO's in effect for this event, and all EDG's and offsite power lines are operable. There was no increase in plant risk as a result of this event.
The NRC Resident Inspector has been notified.
!!!!! THIS EVENT HAS BEEN RETRACTED !!!!!
!!!!! THIS EVENT HAS BEEN RETRACTED !!!!!
Power Reactor
Event Number: 46874
Facility: FERMI
Region: 3 State: MI
Unit: [2] [] []
RX Type: [2] GE-4
NRC Notified By: JIM KONRAD
HQ OPS Officer: JOE O'HARA
Region: 3 State: MI
Unit: [2] [] []
RX Type: [2] GE-4
NRC Notified By: JIM KONRAD
HQ OPS Officer: JOE O'HARA
Notification Date: 05/23/2011
Notification Time: 17:03 [ET]
Event Date: 05/22/2011
Event Time: 14:44 [EDT]
Last Update Date: 06/07/2011
Notification Time: 17:03 [ET]
Event Date: 05/22/2011
Event Time: 14:44 [EDT]
Last Update Date: 06/07/2011
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(v)(A) - POT UNABLE TO SAFE SD
10 CFR Section:
50.72(b)(3)(v)(A) - POT UNABLE TO SAFE SD
Person (Organization):
JAMNES CAMERON (R3DO)
JAMNES CAMERON (R3DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 2 | N | Y | 100 | Power Operation | 100 | Power Operation |
SAFE SHUTDOWN OPERABILITY CONCERN ASSOCIATED WITH OFFSITE POWER CIRCUITS
"On May 22, 2011, at 1444 hours, the Fermi 2 Control Room was notified by the Central System Supervisor that the switchyard voltage for both the 345kV (Division II) and 120kV (Division I) offsite power circuits following a generator trip would not be sufficient to sustain operability of the safety-related loads. Technical Specification (TS) 3.8.1 'AC-Sources Operating,' Condition E was entered at 1444 hours. At 1535, both offsite power circuit voltages were at acceptable levels and the offsite circuits were declared operable. Technical Specification (TS) 3.8.1, Condition E was exited at 1535 hours. Abnormal Operating Procedure (AOP) 20.300 GRID was entered. The Emergency Diesel Generators (EDG) remained operable during the degraded voltage condition. The ability of the EDGs to fulfill their design function was not affected by this condition.
"The event is being reported per 50.72(b)(3)(V)(A), as any event or condition that at the time of discovery could have prevented fulfillment of the safety function of structures or systems that are needed to shutdown the reactor and maintain it in a safe shutdown condition."
The NRC Resident Inspector was notified.
* * * RETRACTION FROM JEFF GROFF TO HOWIE CROUCH AT 1458 EDT ON 6/7/2011 * * *
"This event is retracted. The original report was based on calculated unit trip voltage drop results reported to Detroit Edison by ITC Transmission Company that exceeded acceptance criteria. ITC has subsequently informed Fermi 2 that this notification was in error due to a software feature of their real time contingency analyzer that resulted in inappropriately high results. Based on the results of other similar real time contingency analyzers employed at that time, without the problematic software feature, none of the acceptance criteria were exceeded and both divisions of offsite power were capable of supporting operability of safety-related loads. Additionally, Fermi 2 has determined that even at the inappropriately high voltage drop originally reported, the Division II system could have performed its safety related functions. Therefore, there was no loss of safety function."
The licensee has notified the NRC Resident Inspector. Notified R3DO (Lara).
"On May 22, 2011, at 1444 hours, the Fermi 2 Control Room was notified by the Central System Supervisor that the switchyard voltage for both the 345kV (Division II) and 120kV (Division I) offsite power circuits following a generator trip would not be sufficient to sustain operability of the safety-related loads. Technical Specification (TS) 3.8.1 'AC-Sources Operating,' Condition E was entered at 1444 hours. At 1535, both offsite power circuit voltages were at acceptable levels and the offsite circuits were declared operable. Technical Specification (TS) 3.8.1, Condition E was exited at 1535 hours. Abnormal Operating Procedure (AOP) 20.300 GRID was entered. The Emergency Diesel Generators (EDG) remained operable during the degraded voltage condition. The ability of the EDGs to fulfill their design function was not affected by this condition.
"The event is being reported per 50.72(b)(3)(V)(A), as any event or condition that at the time of discovery could have prevented fulfillment of the safety function of structures or systems that are needed to shutdown the reactor and maintain it in a safe shutdown condition."
The NRC Resident Inspector was notified.
* * * RETRACTION FROM JEFF GROFF TO HOWIE CROUCH AT 1458 EDT ON 6/7/2011 * * *
"This event is retracted. The original report was based on calculated unit trip voltage drop results reported to Detroit Edison by ITC Transmission Company that exceeded acceptance criteria. ITC has subsequently informed Fermi 2 that this notification was in error due to a software feature of their real time contingency analyzer that resulted in inappropriately high results. Based on the results of other similar real time contingency analyzers employed at that time, without the problematic software feature, none of the acceptance criteria were exceeded and both divisions of offsite power were capable of supporting operability of safety-related loads. Additionally, Fermi 2 has determined that even at the inappropriately high voltage drop originally reported, the Division II system could have performed its safety related functions. Therefore, there was no loss of safety function."
The licensee has notified the NRC Resident Inspector. Notified R3DO (Lara).