Event Notification Report for April 21, 2012
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
04/20/2012 - 04/21/2012
Power Reactor
Event Number: 47857
Facility: HARRIS
Region: 2 State: NC
Unit: [1] [] []
RX Type: [1] W-3-LP
NRC Notified By: AL BOSTIC
HQ OPS Officer: MARK ABRAMOVITZ
Region: 2 State: NC
Unit: [1] [] []
RX Type: [1] W-3-LP
NRC Notified By: AL BOSTIC
HQ OPS Officer: MARK ABRAMOVITZ
Notification Date: 04/21/2012
Notification Time: 12:45 [ET]
Event Date: 04/21/2012
Event Time: 05:15 [EDT]
Last Update Date: 04/24/2012
Notification Time: 12:45 [ET]
Event Date: 04/21/2012
Event Time: 05:15 [EDT]
Last Update Date: 04/24/2012
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(v)(C) - POT UNCNTRL RAD REL 50.72(b)(3)(v)(D) - ACCIDENT MITIGATION
10 CFR Section:
50.72(b)(3)(v)(C) - POT UNCNTRL RAD REL 50.72(b)(3)(v)(D) - ACCIDENT MITIGATION
Person (Organization):
REBECCA NEASE (R2DO)
REBECCA NEASE (R2DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | N | N | 0 | Hot Shutdown | 0 | Hot Shutdown |
MAIN STEAM ISOLATION VALVES FAIL TO SHUT
"At approximately 0515 EDT on April 21, 2012, the Harris Nuclear Plant [HNP] was in the process of a normal plant shutdown for a refueling outage. HNP was at 0% power in Mode 4. During OST-1046, MSIV Operability Test, 'B' and 'C' Main Steam Isolation Valves (MSIV), failed to close from the main control board.
"At 0648 EDT an April 21, 2012 'B' MSIV shut immediately after the instrument air supply was isolated.
"At 0938 EDT an April 21, 2012 'C' MSIV shut after the instrument air supply was isolated.
"The cause of the equipment failure is not yet known but is currently being investigated. This report is being made in accordance with 10 CFR 50.72 (b)(3)(v)(C), inability to isolate and mitigate a radioactive release, and 10 CFR 50.72 (b)(3)(v)(D), a condition which could have prevented the fulfillment of a safety function to mitigate the consequences of an accident. The plant continues to remain shutdown at 0% power. Other equipment functioned as expected including the turbine isolation valves."
The licensee notified the NRC Resident Inspector.
* * * UPDATE FROM JOHN CAVES TO HOWIE CROUCH AT 1258 EDT ON 4/24/12 * * *
"Investigation into the condition revealed the instrument air supply to the MSIVs was isolated at 0530 EDT and 'B' MSIV indicated [drifted] shut at 0607 EDT. The plant is currently in Mode 6, Refueling, and the investigation is ongoing."
The licensee notified the NRC Resident Inspector. Notified R2DO (Musser).
"At approximately 0515 EDT on April 21, 2012, the Harris Nuclear Plant [HNP] was in the process of a normal plant shutdown for a refueling outage. HNP was at 0% power in Mode 4. During OST-1046, MSIV Operability Test, 'B' and 'C' Main Steam Isolation Valves (MSIV), failed to close from the main control board.
"At 0648 EDT an April 21, 2012 'B' MSIV shut immediately after the instrument air supply was isolated.
"At 0938 EDT an April 21, 2012 'C' MSIV shut after the instrument air supply was isolated.
"The cause of the equipment failure is not yet known but is currently being investigated. This report is being made in accordance with 10 CFR 50.72 (b)(3)(v)(C), inability to isolate and mitigate a radioactive release, and 10 CFR 50.72 (b)(3)(v)(D), a condition which could have prevented the fulfillment of a safety function to mitigate the consequences of an accident. The plant continues to remain shutdown at 0% power. Other equipment functioned as expected including the turbine isolation valves."
The licensee notified the NRC Resident Inspector.
* * * UPDATE FROM JOHN CAVES TO HOWIE CROUCH AT 1258 EDT ON 4/24/12 * * *
"Investigation into the condition revealed the instrument air supply to the MSIVs was isolated at 0530 EDT and 'B' MSIV indicated [drifted] shut at 0607 EDT. The plant is currently in Mode 6, Refueling, and the investigation is ongoing."
The licensee notified the NRC Resident Inspector. Notified R2DO (Musser).
Power Reactor
Event Number: 47858
Facility: DIABLO CANYON
Region: 4 State: CA
Unit: [1] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: DAN STERMER
HQ OPS Officer: PETE SNYDER
Region: 4 State: CA
Unit: [1] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: DAN STERMER
HQ OPS Officer: PETE SNYDER
Notification Date: 04/22/2012
Notification Time: 02:50 [ET]
Event Date: 04/21/2012
Event Time: 16:15 [PDT]
Last Update Date: 04/25/2012
Notification Time: 02:50 [ET]
Event Date: 04/21/2012
Event Time: 16:15 [PDT]
Last Update Date: 04/25/2012
Emergency Class: NON EMERGENCY
10 CFR Section:
10 CFR Section:
Person (Organization):
NEIL OKEEFE (R4DO)
NEIL OKEEFE (R4DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | N | Y | 82 | Power Operation | 20 | Power Operation |
| 2 | N | Y | 100 | Power Operation | 100 | Power Operation |
APPARENT PHASE IMBALANCE BETWEEN NORMAL AND ALTERNATE POWER CIRCUITS
"On April 21, 2012, at 1615 PDT, Diablo Canyon Power Plant (DCPP) operators identified that an attempted manual transfer of the Unit 1 AC power sources from the normal offsite circuit (500 kv) to the alternate offsite circuit (230 kv) failed.
"The attempted manual transfer of the offsite power source from the normal 500 kv to the alternate 230 kv was a planned activity to shut down Unit 1 for its 17th refueling outage. The failure to manually transfer was concluded to be caused by an indicated out of phase condition between the 500 kv and 230 kv system. DCPP control transfer systems prevent paralleling and transferring the power supplies from the normal to alternate offsite circuit with an out of phase condition. The offsite AC power sources remain capable of being manually transferred from the normal to the alternate source by way of transferring to diesels as an intermediate step.
"The 230 kv system ability to perform its accident mitigation safety function following a reactor trip or safety injection was not affected by the inability to perform a direct manual transfer from the 500 kv offsite power system.
"DCPP staff are currently troubleshooting the out of phase indication and will provide an update when the cause is concluded.
"The licensee notified the NRC Resident Inspector."
* * * UPDATE FROM MIKE QUITTER TO HOWIE CROUCH AT 2013 EDT ON 4/25/12 * * *
"This is an update to EN #47858 reported on April 22, 2012, where Pacific Gas & Electric Company (PG&E) reported that an attempt to manually transfer the DCPP Unit 1 AC power sources from the normal offsite circuit (500 kV) to the alternate required offsite circuit (230 kV) failed.
"PG&E determined that the out-of-phase condition between the 500kV system and the 230 kV system resulted from the offsite power system configurations and conditions existing at the time of the attempted transfer. PG&E established alternate operating guidance to allow operators to perform bus transfers between the 500kV source and the 230 kV source in the event that an out-of-phase condition exists when bus transfer is desired.
"PG&E personnel informed the NRC Resident Inspector."
Notified R4DO (Proulx).
"On April 21, 2012, at 1615 PDT, Diablo Canyon Power Plant (DCPP) operators identified that an attempted manual transfer of the Unit 1 AC power sources from the normal offsite circuit (500 kv) to the alternate offsite circuit (230 kv) failed.
"The attempted manual transfer of the offsite power source from the normal 500 kv to the alternate 230 kv was a planned activity to shut down Unit 1 for its 17th refueling outage. The failure to manually transfer was concluded to be caused by an indicated out of phase condition between the 500 kv and 230 kv system. DCPP control transfer systems prevent paralleling and transferring the power supplies from the normal to alternate offsite circuit with an out of phase condition. The offsite AC power sources remain capable of being manually transferred from the normal to the alternate source by way of transferring to diesels as an intermediate step.
"The 230 kv system ability to perform its accident mitigation safety function following a reactor trip or safety injection was not affected by the inability to perform a direct manual transfer from the 500 kv offsite power system.
"DCPP staff are currently troubleshooting the out of phase indication and will provide an update when the cause is concluded.
"The licensee notified the NRC Resident Inspector."
* * * UPDATE FROM MIKE QUITTER TO HOWIE CROUCH AT 2013 EDT ON 4/25/12 * * *
"This is an update to EN #47858 reported on April 22, 2012, where Pacific Gas & Electric Company (PG&E) reported that an attempt to manually transfer the DCPP Unit 1 AC power sources from the normal offsite circuit (500 kV) to the alternate required offsite circuit (230 kV) failed.
"PG&E determined that the out-of-phase condition between the 500kV system and the 230 kV system resulted from the offsite power system configurations and conditions existing at the time of the attempted transfer. PG&E established alternate operating guidance to allow operators to perform bus transfers between the 500kV source and the 230 kV source in the event that an out-of-phase condition exists when bus transfer is desired.
"PG&E personnel informed the NRC Resident Inspector."
Notified R4DO (Proulx).