Event Notification Report for July 18, 2006
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
07/17/2006 - 07/18/2006
!!!!! THIS EVENT HAS BEEN RETRACTED !!!!!
!!!!! THIS EVENT HAS BEEN RETRACTED !!!!!
Power Reactor
Event Number: 42714
Facility: SUMMER
Region: 2 State: SC
Unit: [1] [] []
RX Type: [1] W-3-LP
NRC Notified By: ARNIE CRIBB
HQ OPS Officer: PETE SNYDER
Region: 2 State: SC
Unit: [1] [] []
RX Type: [1] W-3-LP
NRC Notified By: ARNIE CRIBB
HQ OPS Officer: PETE SNYDER
Notification Date: 07/18/2006
Notification Time: 22:30 [ET]
Event Date: 07/18/2006
Event Time: 17:15 [EDT]
Last Update Date: 08/10/2006
Notification Time: 22:30 [ET]
Event Date: 07/18/2006
Event Time: 17:15 [EDT]
Last Update Date: 08/10/2006
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(v)(B) - POT RHR INOP
10 CFR Section:
50.72(b)(3)(v)(B) - POT RHR INOP
Person (Organization):
MIKE ERNSTES (R2)
MIKE ERNSTES (R2)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | N | Y | 100 | Power Operation | 100 | Power Operation |
POTENTIAL FLOODING COMMON MODE FAILURE OF SERVICE WATER PUMPS
"At 1715, it was determined that current plant configuration does not match the assumptions of the Service Water Pump House flooding design calculation. The calculation assumes that a leak developing in the discharge valve bay would cause the water level to rise to the level of the system piping and then stabilize due to leakage out of the valve bay through the area where the piping penetrated the wall. This level is below any electrical equipment and therefore would have no adverse impact on the system. The area around the piping where it was assumed the water would escape was found to be sealed with a fire barrier material. Since the water could not escape, it would continue to rise until it impacted the pump discharge valve (motor operated valve). This would potentially render the Service Water train inoperable.
"A second issue with the design calculation was discovered in that it assumed the pump discharge bays for the other two pumps were physically isolated from each other. This is not the case. The discharge piping for the three pumps are cross-connected via a line which penetrates all three bays. The area between the cross connect piping and the bay walls is not sealed. Any leakage in one bay will be communicated to all three bays. This results in the potential for a leak in any of the bays to possibly impact the operability of both trains of Service Water."
The licensee has put compensatory measures in place to maintain equipment operability. The licensee has determined that by putting either of the two following compensatory measures in place equipment operability will be maintained:
1. They will provide a continuous watch of the areas to detect water leakage that may cause a flooding concern and close service water pump discharge valves within 15 minutes and secure the affected service water pump, or
2. They will remove the fire seals causing the potential flooding concern in rooms 25-01, 25-02 and 25-03 of the service water pump house.
The licensee notified the NRC Resident Inspector.
*** UPDATE F. LUCAS TO J. KNOKE AT 17:40 EDT ON 08/10/06 ***
The following retraction was submitted by licensee:
"EN #42714 was submitted by South Carolina Electric & Gas Company based on the potential loss of both trains of V.C. Summer Nuclear Station Service Water due to leakage/flooding in the pump discharge valve bays (pits). South Carolina Electric & Gas company retracts EN #42714 based on the following discussion.
"Engineering has performed a more rigorous evaluation of the subject scenario utilizing existing calculations and analyses. Any flood or spray event in the Service Water Pump House operating floor or any one discharge valve pit will eventually propagate to all three pits through the open areas around the pipe penetrations. The pits will fill up to the pipe level and would conceivably continue to fill to the operating floor level. The discharge motor operated valve and the control panel above the floor of each valve pit in this scenario would be submerged and would become disabled. The control panels would be shorted to ground, and would fail the discharge motor operated valves in the as-is open position which would not affect the service water supply of either train.
"Since the motor operated valves fail as-is, this subject scenario would not result in the loss of both trains of service water."
The licensee will notify the NRC Resident Inspector. Contacted R2DO (K. Landis)
"At 1715, it was determined that current plant configuration does not match the assumptions of the Service Water Pump House flooding design calculation. The calculation assumes that a leak developing in the discharge valve bay would cause the water level to rise to the level of the system piping and then stabilize due to leakage out of the valve bay through the area where the piping penetrated the wall. This level is below any electrical equipment and therefore would have no adverse impact on the system. The area around the piping where it was assumed the water would escape was found to be sealed with a fire barrier material. Since the water could not escape, it would continue to rise until it impacted the pump discharge valve (motor operated valve). This would potentially render the Service Water train inoperable.
"A second issue with the design calculation was discovered in that it assumed the pump discharge bays for the other two pumps were physically isolated from each other. This is not the case. The discharge piping for the three pumps are cross-connected via a line which penetrates all three bays. The area between the cross connect piping and the bay walls is not sealed. Any leakage in one bay will be communicated to all three bays. This results in the potential for a leak in any of the bays to possibly impact the operability of both trains of Service Water."
The licensee has put compensatory measures in place to maintain equipment operability. The licensee has determined that by putting either of the two following compensatory measures in place equipment operability will be maintained:
1. They will provide a continuous watch of the areas to detect water leakage that may cause a flooding concern and close service water pump discharge valves within 15 minutes and secure the affected service water pump, or
2. They will remove the fire seals causing the potential flooding concern in rooms 25-01, 25-02 and 25-03 of the service water pump house.
The licensee notified the NRC Resident Inspector.
*** UPDATE F. LUCAS TO J. KNOKE AT 17:40 EDT ON 08/10/06 ***
The following retraction was submitted by licensee:
"EN #42714 was submitted by South Carolina Electric & Gas Company based on the potential loss of both trains of V.C. Summer Nuclear Station Service Water due to leakage/flooding in the pump discharge valve bays (pits). South Carolina Electric & Gas company retracts EN #42714 based on the following discussion.
"Engineering has performed a more rigorous evaluation of the subject scenario utilizing existing calculations and analyses. Any flood or spray event in the Service Water Pump House operating floor or any one discharge valve pit will eventually propagate to all three pits through the open areas around the pipe penetrations. The pits will fill up to the pipe level and would conceivably continue to fill to the operating floor level. The discharge motor operated valve and the control panel above the floor of each valve pit in this scenario would be submerged and would become disabled. The control panels would be shorted to ground, and would fail the discharge motor operated valves in the as-is open position which would not affect the service water supply of either train.
"Since the motor operated valves fail as-is, this subject scenario would not result in the loss of both trains of service water."
The licensee will notify the NRC Resident Inspector. Contacted R2DO (K. Landis)
Power Reactor
Event Number: 42715
Facility: LIMERICK
Region: 1 State: PA
Unit: [1] [2] []
RX Type: [1] GE-4,[2] GE-4
NRC Notified By: DAN SEMETER
HQ OPS Officer: STEVE SANDIN
Region: 1 State: PA
Unit: [1] [2] []
RX Type: [1] GE-4,[2] GE-4
NRC Notified By: DAN SEMETER
HQ OPS Officer: STEVE SANDIN
Notification Date: 07/19/2006
Notification Time: 01:07 [ET]
Event Date: 07/18/2006
Event Time: 22:00 [EDT]
Last Update Date: 07/21/2006
Notification Time: 01:07 [ET]
Event Date: 07/18/2006
Event Time: 22:00 [EDT]
Last Update Date: 07/21/2006
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(xiii) - LOSS COMM/ASMT/RESPONSE
10 CFR Section:
50.72(b)(3)(xiii) - LOSS COMM/ASMT/RESPONSE
Person (Organization):
JOHN KINNEMAN (R1)
JOHN KINNEMAN (R1)
| 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 |
LOSS OF EMERGENCY SIREN CAPABILITY DUE TO ADVERSE WEATHER
"48 of 165 offsite sirens are not functioning due to loss of power/equipment problems because of recent storm. Efforts are in progress to restore power to the affected sirens."
The affected sirens are located in Chester County. Compensatory measures are in effect to alert the public should the need arise.
The licensee informed the NRC Resident Inspector.
*** UPDATE FROM C. PEAKS TO J. KNOKE AT 08:40 EDT ON 07/21/06 ***
The licensee reported that only 22 of 165 sirens are now inoperable. This is less than the reportable (25%) amount of 41 sirens.
The licensee notified the NRC Resident Inspector. Notified R1DO (Kinneman).
"48 of 165 offsite sirens are not functioning due to loss of power/equipment problems because of recent storm. Efforts are in progress to restore power to the affected sirens."
The affected sirens are located in Chester County. Compensatory measures are in effect to alert the public should the need arise.
The licensee informed the NRC Resident Inspector.
*** UPDATE FROM C. PEAKS TO J. KNOKE AT 08:40 EDT ON 07/21/06 ***
The licensee reported that only 22 of 165 sirens are now inoperable. This is less than the reportable (25%) amount of 41 sirens.
The licensee notified the NRC Resident Inspector. Notified R1DO (Kinneman).
Power Reactor
Event Number: 42837
Facility: BROWNS FERRY
Region: 2 State: AL
Unit: [] [2] []
RX Type: [1] GE-4,[2] GE-4,[3] GE-4
NRC Notified By: DON SMITH
HQ OPS Officer: MIKE RIPLEY
Region: 2 State: AL
Unit: [] [2] []
RX Type: [1] GE-4,[2] GE-4,[3] GE-4
NRC Notified By: DON SMITH
HQ OPS Officer: MIKE RIPLEY
Notification Date: 09/12/2006
Notification Time: 11:47 [ET]
Event Date: 07/18/2006
Event Time: 04:47 [CDT]
Last Update Date: 09/12/2006
Notification Time: 11:47 [ET]
Event Date: 07/18/2006
Event Time: 04:47 [CDT]
Last Update Date: 09/12/2006
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):
BINOY DESAI (R2)
BINOY DESAI (R2)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 2 | N | Y | 100 | Power Operation | 100 | Power Operation |
INVALID PRIMARY CONTAINMENT ISOLATION SYSTEM ACTUATION DUE TO LOSS OF POWER TO ONE REACTOR PROTECTION SYSTEM BUS
"This 60-day telephone notification is being made under reporting requirements specified by 10 CFR 50.73(a)(2)(iv)(A) and 10 CFR 50.73(a)(1) to describe an invalid actuation of general containment isolation signals affecting more than one system.
"On July 18, 2006, at 0447 hours CDT, with Unit 2 operating at 100% thermal power, the electrical power to reactor protection system (RPS) bus 2A was interrupted during the performance of surveillance testing on RPS circuit protectors 2A1 and 2A2. The RPS buses 2A and 2B are normally powered from motor-generator (MG) sets 2A and 2B, respectively. During testing or maintenance intervals affecting either the MG set or the normal supply circuit protectors, the affected RPS bus is powered from a transformer supply through alternate power circuit protectors 2C1 and 2C2. Power to RPS bus 2A, which was being powered through the alternate power circuit protectors via a temporary transformer, was interrupted when circuit protector 2C1 actuated on a sensed undervoltage condition. The Primary Containment Isolation System (PCIS) logic circuits powered from RPS bus 2A were de energized, and PCIS logic Groups 2, 3, 6, and 8 were actuated. None of the plant conditions which require PCIS Groups 2, 3, 6, or 8 actuation (e.g., low reactor water level, high drywell pressure, abnormal area radiation levels, high area temperature, etc.) existed, therefore these actuations are considered invalid.
"The following actuations/isolations occurred:
"Group 2: Isolation of the Pressure Suppression Chamber head tank pumps; and Drywell Floor and Equipment Drains Isolation
"Group 3: Isolation of the reactor water clean-up system
"Group 6: Initiation of the Standby Gas Treatment System; Initiation of Control Room Emergency Ventilation; and Isolation of the reactor zone and refuel zone normal ventilation systems.
"Group 8: This logic isolates the Traversing Incore Probes (TIP) if they are inserted. The TIPs were not inserted at the time of this event.
"All equipment responded in accordance with the plant design. Upon loss of power from the alternate source, the surveillance testing was suspended, and RPS Bus 2A was re energized from RPS MG set 2A. The affected logic was reset, and equipment was realigned as appropriate.
"There were no safety consequences or impacts on the health and safety of the public. The event was entered into TVA's corrective action program for evaluation and resolution.
"The NRC senior resident inspector has been notified of this report. Reference corrective action document PER 106999."
"This 60-day telephone notification is being made under reporting requirements specified by 10 CFR 50.73(a)(2)(iv)(A) and 10 CFR 50.73(a)(1) to describe an invalid actuation of general containment isolation signals affecting more than one system.
"On July 18, 2006, at 0447 hours CDT, with Unit 2 operating at 100% thermal power, the electrical power to reactor protection system (RPS) bus 2A was interrupted during the performance of surveillance testing on RPS circuit protectors 2A1 and 2A2. The RPS buses 2A and 2B are normally powered from motor-generator (MG) sets 2A and 2B, respectively. During testing or maintenance intervals affecting either the MG set or the normal supply circuit protectors, the affected RPS bus is powered from a transformer supply through alternate power circuit protectors 2C1 and 2C2. Power to RPS bus 2A, which was being powered through the alternate power circuit protectors via a temporary transformer, was interrupted when circuit protector 2C1 actuated on a sensed undervoltage condition. The Primary Containment Isolation System (PCIS) logic circuits powered from RPS bus 2A were de energized, and PCIS logic Groups 2, 3, 6, and 8 were actuated. None of the plant conditions which require PCIS Groups 2, 3, 6, or 8 actuation (e.g., low reactor water level, high drywell pressure, abnormal area radiation levels, high area temperature, etc.) existed, therefore these actuations are considered invalid.
"The following actuations/isolations occurred:
"Group 2: Isolation of the Pressure Suppression Chamber head tank pumps; and Drywell Floor and Equipment Drains Isolation
"Group 3: Isolation of the reactor water clean-up system
"Group 6: Initiation of the Standby Gas Treatment System; Initiation of Control Room Emergency Ventilation; and Isolation of the reactor zone and refuel zone normal ventilation systems.
"Group 8: This logic isolates the Traversing Incore Probes (TIP) if they are inserted. The TIPs were not inserted at the time of this event.
"All equipment responded in accordance with the plant design. Upon loss of power from the alternate source, the surveillance testing was suspended, and RPS Bus 2A was re energized from RPS MG set 2A. The affected logic was reset, and equipment was realigned as appropriate.
"There were no safety consequences or impacts on the health and safety of the public. The event was entered into TVA's corrective action program for evaluation and resolution.
"The NRC senior resident inspector has been notified of this report. Reference corrective action document PER 106999."