Event Notification Report for November 20, 2011
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
11/19/2011 - 11/20/2011
Power Reactor
Event Number: 47461
Facility: MILLSTONE
Region: 1 State: CT
Unit: [] [] [3]
RX Type: [1] GE-3,[2] CE,[3] W-4-LP
NRC Notified By: JOHN MAGYARIK
HQ OPS Officer: BILL HUFFMAN
Region: 1 State: CT
Unit: [] [] [3]
RX Type: [1] GE-3,[2] CE,[3] W-4-LP
NRC Notified By: JOHN MAGYARIK
HQ OPS Officer: BILL HUFFMAN
Notification Date: 11/20/2011
Notification Time: 20:37 [ET]
Event Date: 11/20/2011
Event Time: 17:58 [EST]
Last Update Date: 11/20/2011
Notification Time: 20:37 [ET]
Event Date: 11/20/2011
Event Time: 17:58 [EST]
Last Update Date: 11/20/2011
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):
JOHN CARUSO (R1DO)
JOHN CARUSO (R1DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 3 | M/R | Y | 2 | Startup | 0 | Hot Standby |
MANUAL REACTOR TRIP DUE TO LOSS OF CONDENSER VACUUM DURING STARTUP
Millstone Unit 3 was manually tripped at low power during startup following the loss of condenser vacuum. The loss of vacuum was caused by the loss of the auxiliary steam boiler. The auxiliary steam boiler supplies gland seal steam to the turbine at low power and without the gland seal steam, the licensee could not maintain a condenser vacuum.
All rods fully inserted and there were no complications during the trip. All systems functioned as required and the unit is stable in Mode 3. There was no impact on Unit 2.
The licensee has notified state and local authorities and the NRC Resident Inspector.
Millstone Unit 3 was manually tripped at low power during startup following the loss of condenser vacuum. The loss of vacuum was caused by the loss of the auxiliary steam boiler. The auxiliary steam boiler supplies gland seal steam to the turbine at low power and without the gland seal steam, the licensee could not maintain a condenser vacuum.
All rods fully inserted and there were no complications during the trip. All systems functioned as required and the unit is stable in Mode 3. There was no impact on Unit 2.
The licensee has notified state and local authorities and the NRC Resident Inspector.
Power Reactor
Event Number: 47491
Facility: SOUTH TEXAS
Region: 4 State: TX
Unit: [] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: ROBERT BRINKLEY
HQ OPS Officer: BILL HUFFMAN
Region: 4 State: TX
Unit: [] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: ROBERT BRINKLEY
HQ OPS Officer: BILL HUFFMAN
Notification Date: 11/30/2011
Notification Time: 16:13 [ET]
Event Date: 11/20/2011
Event Time: 05:46 [CST]
Last Update Date: 11/30/2011
Notification Time: 16:13 [ET]
Event Date: 11/20/2011
Event Time: 05:46 [CST]
Last Update Date: 11/30/2011
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):
THOMAS FARNHOLTZ (R4DO)
THOMAS FARNHOLTZ (R4DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 2 | N | N | 0 | Hot Shutdown | 0 | Hot Standby |
TURBINE TRIP PROTECTION DISABLED WHILE IN MODE 3
"On November 20, 2011 at 0546 hours [CST], STP Unit 2 transitioned modes from Mode 4 to Mode 3. Prior to the mode change, all Solid State Protection System (SSPS) generated turbine trip signals were defeated by a maintenance work activity that installed a jumper in both channels (Train R and S) of non-class relays to the turbine trip circuit. The SSPS signals to the non-class relays that were defeated by the jumpers included the turbine trip from reactor trip breakers open (P4), turbine trip from a reactor trip signal (P-16), and the turbine trip from Steam Generator HI- HI (P-14). T.S. 3.3.2 Items 5a (P4) and 5b (P-14) are required in Modes 1, 2, and 3. The jumpers were removed around 0930 on November 20, 2011 with U2 still in Mode 3.
"Both the UFSAR and TS bases identify that the turbine trip mitigates the consequences of an accident. The TS bases states that an ESFAS initiated turbine trip mitigates the consequences of a steam line break or loss of coolant accident. The accident analysis for SGTR also assumes a turbine trip on a reactor trip to isolate the steam path.
"Although Unit 2 was in Mode 3, with the reactor trip breakers open, and turbine throttle valves closed while the jumpers were installed, this condition is conservatively considered to be a safety system functional failure. If not corrected, this condition could have prevented the fulfillment of the accident mitigating and control of the release of radiation safety functions. A review of the performance of this activity in previous outages was conducted. It was identified that during 2RE14 in April of 2010, a work package for this activity was not closed until after Mode 3. The 60 day LER will address if the jumpers were installed in Mode 3 in April, 2010.
"This was determined to be reportable within 8 hours as required by 10 CFR 50.72(b)(3)(v) parts (C) and (D)."
The licensee did not determine the reportability of this event until 1415 CST on 11/30/11. The licensee has notified the NRC Resident Inspector.
"On November 20, 2011 at 0546 hours [CST], STP Unit 2 transitioned modes from Mode 4 to Mode 3. Prior to the mode change, all Solid State Protection System (SSPS) generated turbine trip signals were defeated by a maintenance work activity that installed a jumper in both channels (Train R and S) of non-class relays to the turbine trip circuit. The SSPS signals to the non-class relays that were defeated by the jumpers included the turbine trip from reactor trip breakers open (P4), turbine trip from a reactor trip signal (P-16), and the turbine trip from Steam Generator HI- HI (P-14). T.S. 3.3.2 Items 5a (P4) and 5b (P-14) are required in Modes 1, 2, and 3. The jumpers were removed around 0930 on November 20, 2011 with U2 still in Mode 3.
"Both the UFSAR and TS bases identify that the turbine trip mitigates the consequences of an accident. The TS bases states that an ESFAS initiated turbine trip mitigates the consequences of a steam line break or loss of coolant accident. The accident analysis for SGTR also assumes a turbine trip on a reactor trip to isolate the steam path.
"Although Unit 2 was in Mode 3, with the reactor trip breakers open, and turbine throttle valves closed while the jumpers were installed, this condition is conservatively considered to be a safety system functional failure. If not corrected, this condition could have prevented the fulfillment of the accident mitigating and control of the release of radiation safety functions. A review of the performance of this activity in previous outages was conducted. It was identified that during 2RE14 in April of 2010, a work package for this activity was not closed until after Mode 3. The 60 day LER will address if the jumpers were installed in Mode 3 in April, 2010.
"This was determined to be reportable within 8 hours as required by 10 CFR 50.72(b)(3)(v) parts (C) and (D)."
The licensee did not determine the reportability of this event until 1415 CST on 11/30/11. The licensee has notified the NRC Resident Inspector.