Event Notification Report for April 02, 2011
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
04/01/2011 - 04/02/2011
EVENT NUMBERS
46883
Power Reactor
Event Number: 46883
Facility: LIMERICK
Region: 1 State: PA
Unit: [] [2] []
RX Type: [1] GE-4,[2] GE-4
NRC Notified By: PAUL MARVEL
HQ OPS Officer: VINCE KLCO
Region: 1 State: PA
Unit: [] [2] []
RX Type: [1] GE-4,[2] GE-4
NRC Notified By: PAUL MARVEL
HQ OPS Officer: VINCE KLCO
Notification Date: 05/25/2011
Notification Time: 11:36 [ET]
Event Date: 04/02/2011
Event Time: 12:18 [EDT]
Last Update Date: 05/25/2011
Notification Time: 11:36 [ET]
Event Date: 04/02/2011
Event Time: 12:18 [EDT]
Last Update Date: 05/25/2011
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):
GLENN DENTEL (R1DO)
GLENN DENTEL (R1DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 2 | N | N | 0 | Refueling | 0 | Refueling |
LOSS OF RPS/UPS POWER SUPPLY
"On Saturday, April 2, 2011, Unit 2 refueling outage activities were in progress. The 2A RPS/UPS Static Inverter was out of service and bypassed with loads transferred to the primary alternate power supply. At 1218 hours, a post maintenance test was performed on the secondary alternate power supply. The inverter alternate power manual transfer switch was transferred from the 'primary alternate' to 'secondary alternate' position to support the post maintenance test. Since the transfer switch is 'break before make' the alternate power supply was interrupted momentarily. This deenergized the 2A RPS/UPS power distribution panel loads including the Division IA and IIA RPS relays and Division IA and IIA NSSSS [Nuclear Steam Supply Shutoff System] relays. Primary containment isolation valves (PCIVs) automatically closed on more than one system. The IB and IIB channels were unaffected.
"The portion of the primary containment isolation system that received an actuation signal functioned successfully. All of the affected open isolation valves automatically closed. The isolation was a partial actuation of the isolation actuation instrumentation.
"This 60-day ENS report is being made per 10CFR 50.73(a)(2)(iv)(A) and 10CFR50.73(a)(1) to report invalid automatic actuations of systems listed in paragraph (a)(2)(iv)(B). The listed system that actuated was general containment isolation signals affecting containment isolation valves in more than one system. Primary containment isolation valves (PCIVs) closed on drywell chilled water (DWCW), reactor enclosure cooling water (RECW), primary containment instrument gas (PCIG), and suppression pool cleanup."
The licensee has notified the NRC Resident Inspector.
"On Saturday, April 2, 2011, Unit 2 refueling outage activities were in progress. The 2A RPS/UPS Static Inverter was out of service and bypassed with loads transferred to the primary alternate power supply. At 1218 hours, a post maintenance test was performed on the secondary alternate power supply. The inverter alternate power manual transfer switch was transferred from the 'primary alternate' to 'secondary alternate' position to support the post maintenance test. Since the transfer switch is 'break before make' the alternate power supply was interrupted momentarily. This deenergized the 2A RPS/UPS power distribution panel loads including the Division IA and IIA RPS relays and Division IA and IIA NSSSS [Nuclear Steam Supply Shutoff System] relays. Primary containment isolation valves (PCIVs) automatically closed on more than one system. The IB and IIB channels were unaffected.
"The portion of the primary containment isolation system that received an actuation signal functioned successfully. All of the affected open isolation valves automatically closed. The isolation was a partial actuation of the isolation actuation instrumentation.
"This 60-day ENS report is being made per 10CFR 50.73(a)(2)(iv)(A) and 10CFR50.73(a)(1) to report invalid automatic actuations of systems listed in paragraph (a)(2)(iv)(B). The listed system that actuated was general containment isolation signals affecting containment isolation valves in more than one system. Primary containment isolation valves (PCIVs) closed on drywell chilled water (DWCW), reactor enclosure cooling water (RECW), primary containment instrument gas (PCIG), and suppression pool cleanup."
The licensee has notified the NRC Resident Inspector.