Alert

Due to a lapse in appropriations, the NRC has ceased normal operations. However, excepted and exempted activities necessary to maintain critical health and safety functions—as well as essential progress on designated critical activities, including those specified in Executive Order 14300—will continue, consistent with the OMB-Approved NRC Lapse Plan.

Event Notification Report for July 11, 2013

U.S. Nuclear Regulatory Commission
Operations Center

Event Reports For
07/10/2013 - 07/11/2013

** EVENT NUMBERS **

49039

49183

49184

!!!!! THIS EVENT HAS BEEN RETRACTED. THIS EVENT HAS BEEN RETRACTED !!!!!
Power Reactor	Event Number: 49039
Facility: MILLSTONE Region: 1 State: CT Unit: [ ] [ ] [3] RX Type: [1] GE-3,[2] CE,[3] W-4-LP NRC Notified By: MICHAEL WEISE HQ OPS Officer: MARK ABRAMOVITZ	Notification Date: 05/16/2013 Notification Time: 10:20 [ET] Event Date: 05/16/2013 Event Time: 02:56 [EDT] Last Update Date: 07/10/2013
Emergency Class: NON EMERGENCY 10 CFR Section: 50.72(b)(3)(iv)(A) - VALID SPECIF SYS ACTUATION	Person (Organization): DAN SCHROEDER (R1DO)

Unit	SCRAM Code	RX CRIT	Initial PWR	Initial RX Mode	Current PWR	Current RX Mode
3	N	N	0	Hot Standby	0	Hot Standby

Event Text

MANUAL REACTOR TRIP DURING CONTROL ROD TESTING

"On May 16, 2013, at 0256 EDT, while in Mode 3 (subcritical), operators manually opened the reactor trip breakers as directed by procedure. During rod drop testing, demand position and digital rod position indication did not agree within procedural limits. As directed by procedure, operators opened the reactor trip breakers. The cause of the discrepancy is under investigation. The plant responded as expected and all rods inserted as required. The plant remains stable in Mode 3.

"This condition is reportable pursuant to 10 CFR 50.72(b)(3)(iv).

"The NRC Senior Resident Inspector has been notified."

* * * RETRACTION FROM TODD STRINGFELLOW TO DANIEL MILLS ON 7/10/2013 AT 1418 EDT * * *

"The purpose of this call is to retract the report made on May 16, 2013, Event Number 49039. Operators manually opened the reactor trip breakers in MODE 3 during hot control rod drop testing as directed by procedure. The condition has been determined to be an invalid actuation of the RPS since boron concentration, and not control rods, were being relied upon for safety function during rod testing. The details of the engineering review will be provided to the NRC Senior Resident Inspector."

Notified R1DO (Cook).

Power Reactor	Event Number: 49183
Facility: MILLSTONE Region: 1 State: CT Unit: [ ] [ ] [3] RX Type: [1] GE-3,[2] CE,[3] W-4-LP NRC Notified By: TODD STRINGFELLOW HQ OPS Officer: DANIEL MILLS	Notification Date: 07/10/2013 Notification Time: 12:46 [ET] Event Date: 07/10/2013 Event Time: 05:13 [EDT] Last Update Date: 07/10/2013
Emergency Class: NON EMERGENCY 10 CFR Section: 50.72(b)(3)(xiii) - LOSS COMM/ASMT/RESPONSE	Person (Organization): WILLIAM COOK (R1DO)

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

Event Text

LOSS OF ASSESSMENT CAPABILITY DUE TO FAILURE OF A & B MAIN STEAM LINE RADIATION MONITORS

"A and B Main Steam Line Radiation Monitors 3MSS-RE75 and 76 have failed and were declared inoperable at 0513 hours July 10, 2013. Repairs have been completed and A and B Main Steam Line Radiation Monitors 3MSS-RE75 and 3MSS-RE76 were returned to service at 0900 hours July 10, 2013. The unit is in Mode 1.

"This event is reportable pursuant to 10 CFR 50.72(b)(3)(xiii) as is any event that results in a major loss of emergency assessment capability, off-site response capability, or off-site communications capability.

"The licensee informed the State of Connecticut, Waterford dispatch, and the NRC Resident Inspector."

Power Reactor	Event Number: 49184
Facility: DIABLO CANYON Region: 4 State: CA Unit: [ ] [2] [ ] RX Type: [1] W-4-LP,[2] W-4-LP NRC Notified By: MICHAEL QUITTER HQ OPS Officer: DANIEL MILLS	Notification Date: 07/10/2013 Notification Time: 16:13 [ET] Event Date: 07/10/2013 Event Time: 09:50 [PDT] Last Update Date: 07/10/2013
Emergency Class: NON EMERGENCY 10 CFR Section: 50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL 50.72(b)(2)(xi) - OFFSITE NOTIFICATION 50.72(b)(3)(iv)(A) - VALID SPECIF SYS ACTUATION	Person (Organization): DAVID PROULX (R4DO)

Unit	SCRAM Code	RX CRIT	Initial PWR	Initial RX Mode	Current PWR	Current RX Mode
2	A/R	Y	100	Power Operation	0	Hot Standby

Event Text

UNIT 2 AUTOMATIC REACTOR TRIP

"On July 10, 2013, at 0950 PDT, the Diablo Canyon Power Plant Unit 2 500kV line differential relay actuated. This action tripped the turbine and opened the generator output breakers to isolate the generator. With the turbine tripped and Unit 2 operating above the P-9 50% power permissive, a reactor trip was initiated from the reactor protection system.

"All plant equipment responded as designed. All three Unit 2 Auxiliary Feedwater pumps started, the Containment Fan Cooling units started and ran in slow speed, and the standby Auxiliary Saltwater train started, all as expected.

"Unit 2 is stable at normal operating temperature and pressure. All power transferred to the plant startup source without incident. Condenser vacuum was maintained.

"The preliminary cause of the differential relay actuation was a flashover of Phase A 500 kV to ground across the Phase A lightning arrestor during maintenance activities to wash the 500 kV insulators.

"NRC Resident Inspector has been informed of this event.

"A press release is planned for local media."

Decay heat is being removed by steam dumps to the condenser. No relief valves lifted during the transient. The steam generators are being supplied by the auxiliary feedwater pumps. There were no injuries to personnel. Unit 1 was not affected.

Page Last Reviewed/Updated Thursday, March 25, 2021