Event Notification Report for September 23, 2005
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
09/22/2005 - 09/23/2005
Power Reactor
Event Number: 42010
Facility: COOPER
Region: 4 State: NE
Unit: [1] [] []
RX Type: [1] GE-4
NRC Notified By: STEVE WHEELER
HQ OPS Officer: STEVE SANDIN
Region: 4 State: NE
Unit: [1] [] []
RX Type: [1] GE-4
NRC Notified By: STEVE WHEELER
HQ OPS Officer: STEVE SANDIN
Notification Date: 09/23/2005
Notification Time: 04:38 [ET]
Event Date: 09/23/2005
Event Time: 00:40 [CDT]
Last Update Date: 09/23/2005
Notification Time: 04:38 [ET]
Event Date: 09/23/2005
Event Time: 00:40 [CDT]
Last Update Date: 09/23/2005
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL 50.72(b)(3)(iv)(A) - VALID SPECIF SYS ACTUATION
10 CFR Section:
50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL 50.72(b)(3)(iv)(A) - VALID SPECIF SYS ACTUATION
Person (Organization):
MICHAEL SHANNON (R4)
MICHAEL SHANNON (R4)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | M/R | Y | 75 | Power Operation | 0 | Hot Shutdown |
MANUAL REACTOR SCRAM DUE TO DEGRADING MAIN CONDENSER VACUUM
"At 0040 hours Central Daylight Time, Cooper Nuclear Station was manually scrammed due to degrading main condenser vacuum. Subsequent to the scram, reactor vessel level lowered to minus 20 inches wide range which corresponds to approximately 140 inches above the top of fuel. A Primary Containment Isolation System (PCIS) group 2 isolation occurred as expected due to the level transient. All automatic actions occurred as expected.
"This report includes both a 4 hour and an 8 hour report. The 4 hour report is being made pursuant to 10CFR50.72(b)(2)(iv)(b), Actuation of RPS when the reactor is critical. The 8 hour report is being made pursuant to 10CFR50.72(b)(3)(iv)(a), Actuation of PCIS group 2 due to expected RPV low level following the scram.
"The NRC Resident Inspector has been informed of the event."
All control rods fully inserted following the scram. All safety-related equipment including Emergency Diesel Generators are operable. Offsite power is stable and available. RPV water level is currently being maintained at approximately 35 inches with feedwater supplied by the condensate pumps. The cause of the degrading main condenser vacuum is unknown and under investigation. The RWCU Heat Exchanger is in service to remove decay heat.
"At 0040 hours Central Daylight Time, Cooper Nuclear Station was manually scrammed due to degrading main condenser vacuum. Subsequent to the scram, reactor vessel level lowered to minus 20 inches wide range which corresponds to approximately 140 inches above the top of fuel. A Primary Containment Isolation System (PCIS) group 2 isolation occurred as expected due to the level transient. All automatic actions occurred as expected.
"This report includes both a 4 hour and an 8 hour report. The 4 hour report is being made pursuant to 10CFR50.72(b)(2)(iv)(b), Actuation of RPS when the reactor is critical. The 8 hour report is being made pursuant to 10CFR50.72(b)(3)(iv)(a), Actuation of PCIS group 2 due to expected RPV low level following the scram.
"The NRC Resident Inspector has been informed of the event."
All control rods fully inserted following the scram. All safety-related equipment including Emergency Diesel Generators are operable. Offsite power is stable and available. RPV water level is currently being maintained at approximately 35 inches with feedwater supplied by the condensate pumps. The cause of the degrading main condenser vacuum is unknown and under investigation. The RWCU Heat Exchanger is in service to remove decay heat.
General Information or Other
Event Number: 42021
Rep Org: WYLE LABORATORIES
Licensee: BUSSMANN
Region: 1
City: HUNTSVILLE State: AL
County:
License #:
Agreement: Y
Docket:
NRC Notified By: BRUCE BATEMAN
HQ OPS Officer: BILL GOTT
Licensee: BUSSMANN
Region: 1
City: HUNTSVILLE State: AL
County:
License #:
Agreement: Y
Docket:
NRC Notified By: BRUCE BATEMAN
HQ OPS Officer: BILL GOTT
Notification Date: 09/27/2005
Notification Time: 17:39 [ET]
Event Date: 09/23/2005
Event Time: 00:00 [CDT]
Last Update Date: 01/25/2006
Notification Time: 17:39 [ET]
Event Date: 09/23/2005
Event Time: 00:00 [CDT]
Last Update Date: 01/25/2006
Emergency Class: NON EMERGENCY
10 CFR Section:
21.21 - UNSPECIFIED PARAGRAPH
10 CFR Section:
21.21 - UNSPECIFIED PARAGRAPH
Person (Organization):
CHRISTOPHER CAHILL (R1)
CHARLIE PAYNE (R2)
DAVID HILLS (R3)
BLAIR SPITZBERG (R4)
TABATABAI (faxed) (NRR)
CHRISTOPHER CAHILL (R1)
CHARLIE PAYNE (R2)
DAVID HILLS (R3)
BLAIR SPITZBERG (R4)
TABATABAI (faxed) (NRR)
MATERIAL DEFECT REPORT
The licensee provided the following information via facsimile:
"Pursuant to 10 CFR Part 21, this letter notifies the NRC of the existence of a possible defect in Bussmann KWN-R fuses.
"The defect is a poor solder connection of the fuse link assembly to the rejection ferrule. The defect applies potentially to all KWN-R fuses.
"An evaluation was performed and determined that this defect can create a substantial safety hazard or contribute to circumstances that would exceed safety limits as defined in the technical specifications of a license issued pursuant to 10CFR50. Safety-related circuits that include fuses with this defect may not be able to perform their safety-related function as required during a design basis event. Therefore, this potential defect is reportable per 10 CFR Part 21.
"DESCRIPTION OF ANOMALY:
The customer reports that the fuse lost electrical continuity while in service. The customer cut the fuse open and found the fuse element intact and a lack of electrical continuity across the soldered connection of the element to the rejection ferrule of the fuse. According to the customer, the fuse had been in service since 3/31/05 carrying 2 - 3 amperes, and there were no overcurrent events which caused the fuse to open.
"DISPOSITION - COMMENTS - RECOMMENDATIONS:
The customer returned the fuse to Wyle for failure analysis. Wyle forwarded the fuse to the manufacturer for evaluation. The manufacturer found a poor solder connection on the rejection cap. Apparently the cap did not get hot enough to reflow solder during the manufacturing process. The manufacturer stated the issue could be isolated to this particular fuse due to placing it in an incorrect bin, but the issue may extend to other fuses due to a process problem. Based on the evaluation, a potential defect exists in other KWN-R fuses.
"As a screening test to ensure a good soldered connection, the manufacturer recommends performing a Current Carrying Capacity Test for 30 minutes at 110% of rated current after warm up at 100% of rated current.
"This anomaly impacts qualification of KWN-R fuses. Only KWN-R fuses that pass the 110% Current Carrying Capacity Test are qualified."
* * *UPDATE PROVIDED BY BATEMAN TO ROTTON AT 0942 EST ON 01/25/06 * * *
The manufacturer provided the following information via fax:
"This letter provides an update to the referenced letter that Wyle submitted to the NRC on the above subject [on 09/27/05]
"The KWN-R fuses affected are limited to [less than or equal to] 30 amps. KTN-R fuses [less than or equal to] 30 amps are added to the referenced Part 21 notification since these fuses are manufactured using the same process as the KWN-R fuses.
"Thus far, poor solder joints have been found in 3, 6, and 10 amp KWN-R fuses. In addition to the date codes previously mentioned (L05, M37, M17), poor solder joints have also been found in date codes L11, L19, M07, M20, M40.
"Poor solder joints have also been found in 3, 4, 5, and 15 amp KTN-R fuses of the 1987-1991, vintage (no date code on fuses).
"When performing the 110% Current-Carrying Capacity Test, the fuses should be warmed up at 100% until their temperature and the voltage drop across them are stable before applying 110% current to avoid blowing the fuses.
"A mechanical drop test has been added to the KWN-R and KTN-R manufacturing process. This drop test should be added to the screening process. The drop test consists of:
1. Measure and record the fuse resistance.
2. Drop the fuse though a 3 foot pipe onto a laminated workbench onto the non-rejection end of the fuse.
3. Measure the fuse resistance after the drop.
4. Acceptance Criteria: Fuse resistance should be the same resistance after the drop (+/- 10%) and within the manufacturer's specified range."
Notified R1DO (Perry), R2DO (Payne), R3DO (Lipa), R4DO (Spitzberg), and NRR (Tabatabai)
The licensee provided the following information via facsimile:
"Pursuant to 10 CFR Part 21, this letter notifies the NRC of the existence of a possible defect in Bussmann KWN-R fuses.
"The defect is a poor solder connection of the fuse link assembly to the rejection ferrule. The defect applies potentially to all KWN-R fuses.
"An evaluation was performed and determined that this defect can create a substantial safety hazard or contribute to circumstances that would exceed safety limits as defined in the technical specifications of a license issued pursuant to 10CFR50. Safety-related circuits that include fuses with this defect may not be able to perform their safety-related function as required during a design basis event. Therefore, this potential defect is reportable per 10 CFR Part 21.
"DESCRIPTION OF ANOMALY:
The customer reports that the fuse lost electrical continuity while in service. The customer cut the fuse open and found the fuse element intact and a lack of electrical continuity across the soldered connection of the element to the rejection ferrule of the fuse. According to the customer, the fuse had been in service since 3/31/05 carrying 2 - 3 amperes, and there were no overcurrent events which caused the fuse to open.
"DISPOSITION - COMMENTS - RECOMMENDATIONS:
The customer returned the fuse to Wyle for failure analysis. Wyle forwarded the fuse to the manufacturer for evaluation. The manufacturer found a poor solder connection on the rejection cap. Apparently the cap did not get hot enough to reflow solder during the manufacturing process. The manufacturer stated the issue could be isolated to this particular fuse due to placing it in an incorrect bin, but the issue may extend to other fuses due to a process problem. Based on the evaluation, a potential defect exists in other KWN-R fuses.
"As a screening test to ensure a good soldered connection, the manufacturer recommends performing a Current Carrying Capacity Test for 30 minutes at 110% of rated current after warm up at 100% of rated current.
"This anomaly impacts qualification of KWN-R fuses. Only KWN-R fuses that pass the 110% Current Carrying Capacity Test are qualified."
* * *UPDATE PROVIDED BY BATEMAN TO ROTTON AT 0942 EST ON 01/25/06 * * *
The manufacturer provided the following information via fax:
"This letter provides an update to the referenced letter that Wyle submitted to the NRC on the above subject [on 09/27/05]
"The KWN-R fuses affected are limited to [less than or equal to] 30 amps. KTN-R fuses [less than or equal to] 30 amps are added to the referenced Part 21 notification since these fuses are manufactured using the same process as the KWN-R fuses.
"Thus far, poor solder joints have been found in 3, 6, and 10 amp KWN-R fuses. In addition to the date codes previously mentioned (L05, M37, M17), poor solder joints have also been found in date codes L11, L19, M07, M20, M40.
"Poor solder joints have also been found in 3, 4, 5, and 15 amp KTN-R fuses of the 1987-1991, vintage (no date code on fuses).
"When performing the 110% Current-Carrying Capacity Test, the fuses should be warmed up at 100% until their temperature and the voltage drop across them are stable before applying 110% current to avoid blowing the fuses.
"A mechanical drop test has been added to the KWN-R and KTN-R manufacturing process. This drop test should be added to the screening process. The drop test consists of:
1. Measure and record the fuse resistance.
2. Drop the fuse though a 3 foot pipe onto a laminated workbench onto the non-rejection end of the fuse.
3. Measure the fuse resistance after the drop.
4. Acceptance Criteria: Fuse resistance should be the same resistance after the drop (+/- 10%) and within the manufacturer's specified range."
Notified R1DO (Perry), R2DO (Payne), R3DO (Lipa), R4DO (Spitzberg), and NRR (Tabatabai)