Event Notification Report for April 21, 2001
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
04/20/2001 - 04/21/2001
Power Reactor
Event Number: 37939
Facility: RIVER BEND
Region: 4 State: LA
Unit: [1] [] []
RX Type: [1] GE-6
NRC Notified By: JOHN CARLSON
HQ OPS Officer: JOHN MacKINNON
Region: 4 State: LA
Unit: [1] [] []
RX Type: [1] GE-6
NRC Notified By: JOHN CARLSON
HQ OPS Officer: JOHN MacKINNON
Notification Date: 04/21/2001
Notification Time: 19:17 [ET]
Event Date: 04/21/2001
Event Time: 14:54 [CDT]
Last Update Date: 04/21/2001
Notification Time: 19:17 [ET]
Event Date: 04/21/2001
Event Time: 14:54 [CDT]
Last Update Date: 04/21/2001
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL
10 CFR Section:
50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL
Person (Organization):
CHARLES MARSCHALL (R4)
CHARLES MARSCHALL (R4)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | A/R | Y | 58 | Power Operation | 0 | Hot Shutdown |
UNEXPECTED AUTOMATIC REACTOR SCRAM DURING TURBINE CONTROL VALVE TESTING
During plant start-up from forced outage 01-01, with the plant at 58% power, an automatic reactor scram occurred. The scram occurred during the main turbine control valve testing due to an apparent turbine pressure control system malfunction. Automatic reactor scram occurred at the RPV High Pressure Scram Setpoint. All other systems functioned as expected during and after the transient. The unit is currently stable in Mode 3, Hot Shutdown, with reactor pressure and level within normal bands. Investigation in progress to determine cause of malfunction. Safety Relief Valves opened and closed during the transient. All Emergency Core Cooling Systems are fully operable and the electrical grid is stable.
The NRC Resident Inspector was notified of this event by the licensee.
During plant start-up from forced outage 01-01, with the plant at 58% power, an automatic reactor scram occurred. The scram occurred during the main turbine control valve testing due to an apparent turbine pressure control system malfunction. Automatic reactor scram occurred at the RPV High Pressure Scram Setpoint. All other systems functioned as expected during and after the transient. The unit is currently stable in Mode 3, Hot Shutdown, with reactor pressure and level within normal bands. Investigation in progress to determine cause of malfunction. Safety Relief Valves opened and closed during the transient. All Emergency Core Cooling Systems are fully operable and the electrical grid is stable.
The NRC Resident Inspector was notified of this event by the licensee.
!!!!! THIS EVENT HAS BEEN RETRACTED !!!!!
!!!!! THIS EVENT HAS BEEN RETRACTED !!!!!
Power Reactor
Event Number: 37937
Facility: QUAD CITIES
Region: 3 State: IL
Unit: [] [2] []
RX Type: [1] GE-3,[2] GE-3
NRC Notified By: JOHN LECHMAIER
HQ OPS Officer: LEIGH TROCINE
Region: 3 State: IL
Unit: [] [2] []
RX Type: [1] GE-3,[2] GE-3
NRC Notified By: JOHN LECHMAIER
HQ OPS Officer: LEIGH TROCINE
Notification Date: 04/21/2001
Notification Time: 07:02 [ET]
Event Date: 04/21/2001
Event Time: 03:20 [CDT]
Last Update Date: 05/14/2001
Notification Time: 07:02 [ET]
Event Date: 04/21/2001
Event Time: 03:20 [CDT]
Last Update Date: 05/14/2001
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(v)(D) - ACCIDENT MITIGATION
10 CFR Section:
50.72(b)(3)(v)(D) - ACCIDENT MITIGATION
Person (Organization):
RONALD GARDNER (R3)
RONALD GARDNER (R3)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 2 | N | Y | 100 | Power Operation | 100 | Power Operation |
UNIT 2 HPCI INOPERABLE DUE TO FAILED TURBINE EXHAUST LINE VACUUM BREAKER CHECK VALVES
The following text is a portion of a facsimile received from the licensee:
"At 0320 [CDT] on April 21, 2001, Unit [2] HPCI was declared inoperable when two check valves failed to meet acceptance criteria during the performance of [procedure] QCOS 2300-18, HPCI STEAM EXHAUST VACUUM BREAKER LINE CHECK VALVES IST FUNCTIONAL TEST. Two of the four HPCI turbine exhaust line vacuum breaker check valves were found to have failed to close. The exhaust line containing the failed check valves was isolated at the start of the surveillance using motor-operated isolation valves contained in the exhaust line. The failed check valves remain isolated."
The licensee stated that Unit 2 is in a 14-day limiting condition for operation as a result of this issue.
The licensee notified the NRC resident inspector.
***** RETRACTION RECEIVED AT 1829 EDT ON 05/14/01 FROM TOM OSELAND TO LEIGH TROCINE *****
The following text is a portion of a facsimile received from the licensee:
"We have completed our evaluation and have determined that the HPCI [system] was always capable of performing its intended safety function."
"BACKGROUND"
"On 4/21/01 at 0116 hours [CDT], plant operators began surveillance QCOS 2300-18, 'HPCI Steam Exhaust Vacuum Breaker Line Check Valves IST Functional Test.' The surveillance test is performed to confirm that valves 2-2399-64 and 2-2399-65 open and close by applying air pressure to the check valves. During the test, these valves were found to meet the acceptance criteria in the open direction. The function of these valves is to open to provide a flow path from the suppression chamber to the HPCI turbine steam exhaust piping to prevent a vacuum. Following HPCI operation, the steam condensing in the suppression pool and exhaust line would cause the suppression pool water to be drawn up the exhaust piping."
"At 0320 hours [CDT], the station equipment operator performing the test indicated that the 2-2399-64 and 2-2399-65 valves failed to close. These valves must close during HPCI operation to prevent steam flow from the HPCI turbine steam exhaust piping to the suppression chamber. Station operators declared the HPCI system inoperable when the test revealed that these valves did not close. Subsequently, operators initiated an ENS phone call to the NRC in accordance with the Exelon reportability manual SAF 1.8, 'Event or Condition That Could Have Prevented Fulfillment of a Safety Function' (10CFR50.72(b)(3)(v))."
"Repairs were initiated, and at 1806 hours [CDT] on 4/21/01. Following repairs, the HPCI vacuum breaker valves 2- 2399-64 and 2- 2399-65 passed the IST test criteria and HPCI was declared operable."
"At approximately 1200 hours [CDT] on 4/22/01, the operators tested the 2-2399-66 and 2-2399-67 valves. They were found to meet the acceptance criteria in both the open and closed direction. These valves are a redundant set to the 2-2399-64 and 2-2399-65 valves."
"ANALYSIS"
"The 2-2399-64 valve and 2-2399-66 valve are in series on the same line. This same configuration also exists on a different line for the 2- 2399-65 and 2-2399-67 valves [...]."
"During HPCI operation, either the 2-2399-64 valve or the 2-2399-66 valve and either the 2-2399-65 valve or the 2-2399-67 valve must close to prevent HPCI exhaust steam from flowing to the suppression chamber atmosphere which would cause an increase in containment pressure and temperature. The HPCI system is designed to exhaust the steam to the suppression pool. The exhaust is discharged below the water level in the suppression pool to ensure the steam is condensed."
"The acceptable test results of the 2399-67 and 2399-66 valves would allow HPCI exhaust steam during operation to be discharged below the water level of the suppression chamber to ensure that steam was condensed and HPCI operation would not be impeded."
"Although, the failure of the 2-2399-64 and 2-2399-65 to close was identified the as-found acceptable condition (ability to close) of the 2-2399-67 and 2-2399-66 valves would have ensured the ability of the vacuum breaker line to perform as required and thus allow HPCI to meet its safety function."
"Based on the above, it has been concluded that HPCI was always capable of performing its safety function." Therefore, the licensee is retracting this event notification.
The licensee notified the NRC resident inspector. The NRC operations officer notified the R3DO (Shear).
The following text is a portion of a facsimile received from the licensee:
"At 0320 [CDT] on April 21, 2001, Unit [2] HPCI was declared inoperable when two check valves failed to meet acceptance criteria during the performance of [procedure] QCOS 2300-18, HPCI STEAM EXHAUST VACUUM BREAKER LINE CHECK VALVES IST FUNCTIONAL TEST. Two of the four HPCI turbine exhaust line vacuum breaker check valves were found to have failed to close. The exhaust line containing the failed check valves was isolated at the start of the surveillance using motor-operated isolation valves contained in the exhaust line. The failed check valves remain isolated."
The licensee stated that Unit 2 is in a 14-day limiting condition for operation as a result of this issue.
The licensee notified the NRC resident inspector.
***** RETRACTION RECEIVED AT 1829 EDT ON 05/14/01 FROM TOM OSELAND TO LEIGH TROCINE *****
The following text is a portion of a facsimile received from the licensee:
"We have completed our evaluation and have determined that the HPCI [system] was always capable of performing its intended safety function."
"BACKGROUND"
"On 4/21/01 at 0116 hours [CDT], plant operators began surveillance QCOS 2300-18, 'HPCI Steam Exhaust Vacuum Breaker Line Check Valves IST Functional Test.' The surveillance test is performed to confirm that valves 2-2399-64 and 2-2399-65 open and close by applying air pressure to the check valves. During the test, these valves were found to meet the acceptance criteria in the open direction. The function of these valves is to open to provide a flow path from the suppression chamber to the HPCI turbine steam exhaust piping to prevent a vacuum. Following HPCI operation, the steam condensing in the suppression pool and exhaust line would cause the suppression pool water to be drawn up the exhaust piping."
"At 0320 hours [CDT], the station equipment operator performing the test indicated that the 2-2399-64 and 2-2399-65 valves failed to close. These valves must close during HPCI operation to prevent steam flow from the HPCI turbine steam exhaust piping to the suppression chamber. Station operators declared the HPCI system inoperable when the test revealed that these valves did not close. Subsequently, operators initiated an ENS phone call to the NRC in accordance with the Exelon reportability manual SAF 1.8, 'Event or Condition That Could Have Prevented Fulfillment of a Safety Function' (10CFR50.72(b)(3)(v))."
"Repairs were initiated, and at 1806 hours [CDT] on 4/21/01. Following repairs, the HPCI vacuum breaker valves 2- 2399-64 and 2- 2399-65 passed the IST test criteria and HPCI was declared operable."
"At approximately 1200 hours [CDT] on 4/22/01, the operators tested the 2-2399-66 and 2-2399-67 valves. They were found to meet the acceptance criteria in both the open and closed direction. These valves are a redundant set to the 2-2399-64 and 2-2399-65 valves."
"ANALYSIS"
"The 2-2399-64 valve and 2-2399-66 valve are in series on the same line. This same configuration also exists on a different line for the 2- 2399-65 and 2-2399-67 valves [...]."
"During HPCI operation, either the 2-2399-64 valve or the 2-2399-66 valve and either the 2-2399-65 valve or the 2-2399-67 valve must close to prevent HPCI exhaust steam from flowing to the suppression chamber atmosphere which would cause an increase in containment pressure and temperature. The HPCI system is designed to exhaust the steam to the suppression pool. The exhaust is discharged below the water level in the suppression pool to ensure the steam is condensed."
"The acceptable test results of the 2399-67 and 2399-66 valves would allow HPCI exhaust steam during operation to be discharged below the water level of the suppression chamber to ensure that steam was condensed and HPCI operation would not be impeded."
"Although, the failure of the 2-2399-64 and 2-2399-65 to close was identified the as-found acceptable condition (ability to close) of the 2-2399-67 and 2-2399-66 valves would have ensured the ability of the vacuum breaker line to perform as required and thus allow HPCI to meet its safety function."
"Based on the above, it has been concluded that HPCI was always capable of performing its safety function." Therefore, the licensee is retracting this event notification.
The licensee notified the NRC resident inspector. The NRC operations officer notified the R3DO (Shear).
Power Reactor
Event Number: 37938
Facility: PILGRIM
Region: 1 State: MA
Unit: [1] [] []
RX Type: [1] GE-3
NRC Notified By: ERIC OLSON
HQ OPS Officer: LEIGH TROCINE
Region: 1 State: MA
Unit: [1] [] []
RX Type: [1] GE-3
NRC Notified By: ERIC OLSON
HQ OPS Officer: LEIGH TROCINE
Notification Date: 04/21/2001
Notification Time: 10:19 [ET]
Event Date: 04/21/2001
Event Time: 08:53 [EDT]
Last Update Date: 04/21/2001
Notification Time: 10:19 [ET]
Event Date: 04/21/2001
Event Time: 08:53 [EDT]
Last Update Date: 04/21/2001
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):
WILLIAM RULAND (R1)
WILLIAM RULAND (R1)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | N | N | 0 | Hot Shutdown | 0 | Hot Shutdown |
UNANTICIPATED AUTOMATIC MAIN STEAM ISOLATION VALVE (MSIV) CLOSURE AND REACTOR WATER CLEANUP [RWCU] SYSTEM ISOLATION DUE TO LEVEL RACK REFERENCE LEG NOTCHING
The following text is a portion of a facsimile received from the licensee:
"During cooldown of the reactor vessel with all rods fully inserted, the [MSIVs] automatically closed in response to a reactor high level concurrent with low reactor pressure (main steam line pressure <810 with reactor level at
+55.4 inches). Reactor pressure was at 100 psig when the isolation occurred. Approximately 1 hour later, another level perturbation occurred resulting in automatic isolation of the [RWCU] system and the inboard MSIV drain valve. The level perturbations are occurring in the 'A' train level rack only. It appears to be caused by non-condensable gasses coming out of solution in the 'A' level rack reference leg (notching). The 'A' train water level indication system is considered to be inoperable, and the applicable [limiting condition for operation] actions have been taken."
The licensee stated that a planned reactor scram was performed prior to this event in order to facilitate commencement of a scheduled refueling outage. Apparently, the RWCU system isolation resulted from a spurious low level signal to the actuation system when the reference leg was being back filled. This was reported to be so quick that it was not seen on any control room instruments. The RWCU system has been placed back in service and is being used for level control. The MSIVs are still closed, but the isolation signal has been reset. However, the notching phenomenon is still being experienced.
The licensee plans to change the decay heat removal path from the main steam system and place the RCIC system in test mode. As the reference leg is back filled and flushed out, the licensee plans to plan to go back to utilization of the main steam system.
The NRC resident inspector has been notified.
The following text is a portion of a facsimile received from the licensee:
"During cooldown of the reactor vessel with all rods fully inserted, the [MSIVs] automatically closed in response to a reactor high level concurrent with low reactor pressure (main steam line pressure <810 with reactor level at
+55.4 inches). Reactor pressure was at 100 psig when the isolation occurred. Approximately 1 hour later, another level perturbation occurred resulting in automatic isolation of the [RWCU] system and the inboard MSIV drain valve. The level perturbations are occurring in the 'A' train level rack only. It appears to be caused by non-condensable gasses coming out of solution in the 'A' level rack reference leg (notching). The 'A' train water level indication system is considered to be inoperable, and the applicable [limiting condition for operation] actions have been taken."
The licensee stated that a planned reactor scram was performed prior to this event in order to facilitate commencement of a scheduled refueling outage. Apparently, the RWCU system isolation resulted from a spurious low level signal to the actuation system when the reference leg was being back filled. This was reported to be so quick that it was not seen on any control room instruments. The RWCU system has been placed back in service and is being used for level control. The MSIVs are still closed, but the isolation signal has been reset. However, the notching phenomenon is still being experienced.
The licensee plans to change the decay heat removal path from the main steam system and place the RCIC system in test mode. As the reference leg is back filled and flushed out, the licensee plans to plan to go back to utilization of the main steam system.
The NRC resident inspector has been notified.