Event Notification Report for March 24, 2011
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
03/23/2011 - 03/24/2011
Power Reactor
Event Number: 46694
Facility: BRAIDWOOD
Region: 3 State: IL
Unit: [] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: SCOTT BUTLER
HQ OPS Officer: JOHN SHOEMAKER
Region: 3 State: IL
Unit: [] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: SCOTT BUTLER
HQ OPS Officer: JOHN SHOEMAKER
Notification Date: 03/24/2011
Notification Time: 11:39 [ET]
Event Date: 03/24/2011
Event Time: 10:18 [CDT]
Last Update Date: 03/24/2011
Notification Time: 11:39 [ET]
Event Date: 03/24/2011
Event Time: 10:18 [CDT]
Last Update Date: 03/24/2011
Emergency Class: UNUSUAL EVENT
10 CFR Section:
50.72(a) (1) (i) - EMERGENCY DECLARED
10 CFR Section:
50.72(a) (1) (i) - EMERGENCY DECLARED
Person (Organization):
JAMNES CAMERON (R3DO)
WILLIAM GOTT (IRD)
ERIC LEEDS (NRR)
CYNTHIA PEDERSON (R3)
JOHN KNOX (DHS)
JAMNES CAMERON (R3DO)
WILLIAM GOTT (IRD)
ERIC LEEDS (NRR)
CYNTHIA PEDERSON (R3)
JOHN KNOX (DHS)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 2 | N | Y | 100 | Power Operation | 100 | Power Operation |
UNEXPECTED LOSS OF ANNUCIATORS DURING PLANNED MAINTENANCE
"During a planned maintenance activity on the Unit 2 main control room alarm cabinets, it was identified that all Unit 2 safety system annunciators were lost. This was identified at 1006 [CDT]. Main Control Board indicators remained functional. At 1018 [CDT], the Shift Manager declared an Unusual Event under Emergency Action Level MU6. This was due to an unplanned loss of most (approximately 75%) safety system annunciators for > 15 minutes. The planned maintenance activity was not expected to affect the amount of annunciators that were lost.
"At 1030 [CST], the [planned maintenance] clearance order was cleared and power was restored to the Unit 2 annunciators."
There was not transient on other plant equipment and the plant remained stable before and after this event. The cause for the unexpected loss of annunciators is not clearly understood and is still under investigation.
The licensee notified the NRC Resident Inspector.
* * * UPDATE FROM SCOTT BUTLER TO JOHN SHOEMAKER AT 1216 EDT ON 03/24/11 * * *
The Unusual Event was terminated at 1047 CDT on 03/24/11. All annunciators have been restored and an investigation will be conducted to determine the cause.
Notified R3DO (Cameron)
"During a planned maintenance activity on the Unit 2 main control room alarm cabinets, it was identified that all Unit 2 safety system annunciators were lost. This was identified at 1006 [CDT]. Main Control Board indicators remained functional. At 1018 [CDT], the Shift Manager declared an Unusual Event under Emergency Action Level MU6. This was due to an unplanned loss of most (approximately 75%) safety system annunciators for > 15 minutes. The planned maintenance activity was not expected to affect the amount of annunciators that were lost.
"At 1030 [CST], the [planned maintenance] clearance order was cleared and power was restored to the Unit 2 annunciators."
There was not transient on other plant equipment and the plant remained stable before and after this event. The cause for the unexpected loss of annunciators is not clearly understood and is still under investigation.
The licensee notified the NRC Resident Inspector.
* * * UPDATE FROM SCOTT BUTLER TO JOHN SHOEMAKER AT 1216 EDT ON 03/24/11 * * *
The Unusual Event was terminated at 1047 CDT on 03/24/11. All annunciators have been restored and an investigation will be conducted to determine the cause.
Notified R3DO (Cameron)
Power Reactor
Event Number: 46697
Facility: NORTH ANNA
Region: 2 State: VA
Unit: [1] [2] []
RX Type: [1] W-3-LP,[2] W-3-LP
NRC Notified By: DON TAYLOR
HQ OPS Officer: CHARLES TEAL
Region: 2 State: VA
Unit: [1] [2] []
RX Type: [1] W-3-LP,[2] W-3-LP
NRC Notified By: DON TAYLOR
HQ OPS Officer: CHARLES TEAL
Notification Date: 03/25/2011
Notification Time: 11:14 [ET]
Event Date: 03/24/2011
Event Time: 14:00 [EDT]
Last Update Date: 03/25/2011
Notification Time: 11:14 [ET]
Event Date: 03/24/2011
Event Time: 14:00 [EDT]
Last Update Date: 03/25/2011
Emergency Class: NON EMERGENCY
10 CFR Section:
10 CFR Section:
Person (Organization):
DANIEL RICH (R2DO)
MARISSA BAILEY (NMSS)
DANIEL RICH (R2DO)
MARISSA BAILEY (NMSS)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | N | Y | 100 | Power Operation | 100 | Power Operation |
| 2 | N | Y | 100 | Power Operation | 100 | Power Operation |
NON-COMPLIANCE WITH NUHOMS TECHNICAL SPECIFICATION
"This 24-hour report is being issued in accordance with the requirements of NRC Certificate of Compliance 1030, Amendment 0, for the NUHOMS Storage System, Technical Specification (TS) 2.2, Functional Operating Limit Violations.
"During a review of historical North Anna NUHOMS dry storage canister (DSC) loading certification documents, a discrepancy was identified. The NUHOMS Certificate of Compliance 1030 Amendment 0 Technical Specifications include a Figure 2, "Heat Load Zones" which specifies the maximum decay heat load for each of the 32 assembly locations in a DSC. The figure includes limits for two zone '1b' locations and two zone '1a' locations in the four center locations of the DSC. The zone '1b' decay heat limit of 0.8 kw is specified for the two 'upper compartments' and zone '1a' decay heat limit of 1.05 kw is specified for the two 'lower compartments' on the figure. Contrary to this, the loading certifications for 7 of 10 DSCs already loaded at NAPS (North Anna Power Station) were not developed to maintain this orientation when loaded in the horizontal storage module (HSM). As a result, the DSC zone '1b' heat load limits were exceeded in some cases for these 7 DSCs.
"The heat load limit for all other zones in the DSCs are symmetric, and those assemblies were verified to the correct limit and are unaffected by this error. In addition the total heat load limit for the sum of the center assemblies was met for all DSCs. The maximum heat load of any zone '1b' assembly at the time of loading was 0.859 kw, which is slightly higher than the 0.8 kw limit. The lower heat load of assemblies in the other compartments offset the slightly higher heat load effects, and it is expected that the thermal analysis acceptance criteria would still have been met at the time of loading.
"The decay heat of the assemblies has continued to decrease since their initial loading and it was confirmed that 12 of the 13 assemblies that initially exceeded the 0.8 kw limit currently meet the zone '1b' heat load limits. The current decay heat of the remaining assembly is slightly above the 0.8 kw limit. Based on the offsetting margins identified above all of the affected DSCs are currently in a safe condition as loaded in the HSMs."
The NRC Resident Inspector has been informed.
"This 24-hour report is being issued in accordance with the requirements of NRC Certificate of Compliance 1030, Amendment 0, for the NUHOMS Storage System, Technical Specification (TS) 2.2, Functional Operating Limit Violations.
"During a review of historical North Anna NUHOMS dry storage canister (DSC) loading certification documents, a discrepancy was identified. The NUHOMS Certificate of Compliance 1030 Amendment 0 Technical Specifications include a Figure 2, "Heat Load Zones" which specifies the maximum decay heat load for each of the 32 assembly locations in a DSC. The figure includes limits for two zone '1b' locations and two zone '1a' locations in the four center locations of the DSC. The zone '1b' decay heat limit of 0.8 kw is specified for the two 'upper compartments' and zone '1a' decay heat limit of 1.05 kw is specified for the two 'lower compartments' on the figure. Contrary to this, the loading certifications for 7 of 10 DSCs already loaded at NAPS (North Anna Power Station) were not developed to maintain this orientation when loaded in the horizontal storage module (HSM). As a result, the DSC zone '1b' heat load limits were exceeded in some cases for these 7 DSCs.
"The heat load limit for all other zones in the DSCs are symmetric, and those assemblies were verified to the correct limit and are unaffected by this error. In addition the total heat load limit for the sum of the center assemblies was met for all DSCs. The maximum heat load of any zone '1b' assembly at the time of loading was 0.859 kw, which is slightly higher than the 0.8 kw limit. The lower heat load of assemblies in the other compartments offset the slightly higher heat load effects, and it is expected that the thermal analysis acceptance criteria would still have been met at the time of loading.
"The decay heat of the assemblies has continued to decrease since their initial loading and it was confirmed that 12 of the 13 assemblies that initially exceeded the 0.8 kw limit currently meet the zone '1b' heat load limits. The current decay heat of the remaining assembly is slightly above the 0.8 kw limit. Based on the offsetting margins identified above all of the affected DSCs are currently in a safe condition as loaded in the HSMs."
The NRC Resident Inspector has been informed.