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Event Notification Report for April 29, 2014

U.S. Nuclear Regulatory Commission
Operations Center

Event Reports For
04/28/2014 - 04/29/2014

** EVENT NUMBERS **


50062 50063

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Power Reactor Event Number: 50062
Facility: MCGUIRE
Region: 2 State: NC
Unit: [1] [2] [ ]
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: SCOTT SLIETER
HQ OPS Officer: DONALD NORWOOD
Notification Date: 04/27/2014
Notification Time: 17:44 [ET]
Event Date: 04/27/2014
Event Time: 16:00 [EDT]
Last Update Date: 04/28/2014
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(xiii) - LOSS COMM/ASMT/RESPONSE
Person (Organization):
MICHAEL F. KING (R2DO)

Unit SCRAM Code RX CRIT Initial PWR Initial RX Mode Current PWR Current RX Mode
1 N Y 100 Power Operation 100 Power Operation
2 N Y 100 Power Operation 100 Power Operation

Event Text

TECHNICAL SUPPORT CENTER OUT-OF-SERVICE

"The Technical Support Center (TSC) cooling system is not operating properly. The temperature of the TSC is currently 80 degrees F. The TSC is still capable of being pressurized."

If needed, facilities in the Admin building are available for use as the back-up TSC.

The licensee will notify the NRC Resident Inspector.

* * * UPDATE AT 1133 EDT ON 04/28/14 FROM SHAUGHN RICE TO S. SANDIN * * *

"TSC Ventilation (VH) System is out-of-service. TSC is not capable of being pressurized, filtered or cooled. This is planned maintenance for work to repair leak reported on 04/27/14."

The licensee informed the NRC Resident Inspector. Notified R2DO (King).

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Power Reactor Event Number: 50063
Facility: ARKANSAS NUCLEAR
Region: 4 State: AR
Unit: [ ] [2] [ ]
RX Type: [1] B&W-L-LP,[2] CE
NRC Notified By: MARK REID
HQ OPS Officer: DONG HWA PARK
Notification Date: 04/27/2014
Notification Time: 23:57 [ET]
Event Date: 04/27/2014
Event Time: 20:12 [CDT]
Last Update Date: 04/28/2014
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
Person (Organization):
RAY AZUA (R4DO)

Unit SCRAM Code RX CRIT Initial PWR Initial RX Mode Current PWR Current RX Mode
2 A/R Y 51 Power Operation 0 Hot Standby

Event Text

AUTOMATIC REACTOR TRIP DUE TO AN AUXILIARY TRIP ON CORE PROTECTION CALCULATOR

"At approximately 1932 [CDT] on 4/27/2014, the System Operations Center (SOC - Dispatcher) informed Unit 2 of a system wide grid emergency and ordered both Unit 1 and Unit 2 to come off line as soon as possible.

"At approximately 2012 [CDT], Unit 2 automatically tripped from 51% power due to an Auxiliary Trip on CPCs (Core Protection Calculator) due to Axial Shape Index (ASI) trip. All Control Element Assemblies inserted into the core. Both vital and non-vital 4160V and 6900V buses remain powered from Startup #3 Transformer. All Systems responded as designed.

"At 1932 [CDT], Unit 1 commenced a Rapid Plant Shutdown at a rate 5-7% per min with the intention to take the turbine offline and leave the reactor critical at 10-12% power on the Turbine Bypass Valves. When the Unit 2 reactor tripped, Unit 1 stopped the power reduction and stabilized the plant at approximately 19% Reactor Power and 125 Generated Megawatts. With SOC concurrence, Unit 1 stabilized power and was told to limit site output to <200 MWe.

At 1932 CDT, Unit 1 began a down power from 100% power and Unit 2 began a down power from 95% power. On Unit 2, decay heat is being removed by the main condenser using the turbine bypass valves. Unit 2 is stable in Mode 3 with stable offsite power. The system wide grid emergency is believed to be caused by tornados in the region.

The licensee has notified the NRC Resident Inspector and the State.

Page Last Reviewed/Updated Wednesday, May 14, 2014
Wednesday, May 14, 2014