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Nuclear Event – Equipment Fire or Explosion/Automatic Reactor SCRAM: Turkey Point Nuclear Generating Station (Unit 3), Biscayne Bay, Florida

2017/03/20

North America – USA | State of Florida,  Turkey Point Nuclear Generating Station, Unit 3
Location: 25°26’03.0″N 80°19’50.0″W
Present Operational Age: ~45 years
Event: INDICATIONS OF FIRE IN SAFETY RELATED SWITCHGEAR
Emergency Class: ALERT
10 CFR Section: 50.72(a) (1) (i) – EMERGENCY DECLARED

Nuclear Event in USA on Thursday, 18 March, 2017 at 11:19 [EDT].

ALERT DECLARED FOR INDICATIONS OF FIRE IN SAFETY RELATED SWITCHGEAR

“Alert declared at 1119 EDT 3/18/17 based on EAL H.A.2 – Fire or Explosion affecting plant safety systems. Fire alarms in the Unit 3 4kV switchgear rooms resulting in a loss of the 3A 4kV bus and trip of all three Reactor Coolant Pumps. The reactor tripped and was stabilized in Mode 3. No actual fire was observed. The 3A 4kV is deenergized. The 3B Reactor Coolant Pump was restarted for forced circulation. All other safety systems functioned as required. A refueling outage was scheduled to begin on 3/20/17.”

All control rods fully inserted on the reactor trip. Decay heat is being removed using feedwater and steam generator atmospheric steam dumps. One person was injured with a minor burn and possible sprained ankle and was taken to a local hospital.

The licensee notified the NRC Resident Inspector.

Notified DHS SWO, DOE, FEMA, HHS, NICC, USDA, EPA, FDA (e-mail), NWC (e-mail), NNSA (e-mail), and NRCC SASC (e-mail).

* * * UPDATE AT 1426 EDT ON 3/18/2017 FROM DAN HAGARDY TO BETHANY CECERE * * *

“Unit 3 was determined by the Emergency Coordinator to be in a safe and stable condition, the Emergency Plan personnel at the Technical Support Center and Emergency Operations Facility were no longer required for support, the Operations Support Center was staffed for recovery efforts, and plant personnel were sufficient and capable for continuing mitigation efforts.

“Investigation of the fault on the 3A 4kV bus is ongoing.

“Based on the above conditions, the Alert was exited at 1420 hours [on 3/18/2017].”

The injured electrician was taken to an offsite hospital to treat minor burns and possible sprained ankle.

The licensee notified the NRC Resident Inspector.

Notified the R2DO (Ehrhardt), NRR EO (Miller and King), IRD MOC (Stapleton), DHS SWO, DOE, FEMA, HHS, NICC, USDA, EPA, FDA (e-mail), NWC (e-mail), NNSA (e-mail), and NRCC SASC (e-mail).

Source: NRC  Event Number:  52621


Nuclear Event in USA on Thursday, 18 March, 2017 at 11:07 [EDT].

Event: AUTOMATIC REACTOR TRIP/PLANT S/D

Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(2)(iv)(B) – RPS ACTUATION – CRITICAL
50.72(b)(2)(i) – PLANT S/D REQD BY TS
50.72(b)(3)(iv)(A) – VALID SPECIF SYS ACTUATION
50.72(b)(3)(v)(D) – ACCIDENT MITIGATION

REACTOR TRIP AND LOSS OF ABILITY FOR UNIT 4 TO SUPPLY POWER TO UNIT 3

“On 3/18/17 at 1107 [EDT], the Unit 3 reactor tripped as a result of the loss of the 3A 4kV bus. All three reactor coolant pumps (RCP) tripped and the 3B RCP was restarted for forced recirculation. The reactor is stable in Mode 3. The 3A 4kV bus remains deenergized until troubleshooting and repairs are complete. In addition, Technical Specification 3.8.1.1, Action C requires a four hour report for the concurrent inoperability of the Unit 4 startup transformer to Unit 3 via the 3A 4kV bus and the Unit 3 3A diesel generator.

“The NRC Senior Resident Inspector will be notified.”

* * * UPDATE ON 3/18/2017 AT 1854 EDT FROM JAMES SPICHER TO BETHANY CECERE * * *

“Update to previous report (EN 52623) to include additional reporting criteria.

“On 3/18/17 at 1107 [EDT] the Unit 3 reactor tripped as a result of the loss of the 3A 4kV bus. The 3A Emergency Diesel Generator (EDG) started on the loss of power signal but did not load, as designed, due to the bus fault. The 3A EDG was manually stopped at 1332. The Auxiliary Feedwater (AFW) System also initiated as expected. AFW was stopped at 1135. The actuations of the 3A EDG and AFW are reportable in accordance with 10 CFR 50.72(b)(3)(iv)(A).

“A loss of safety function affecting Units 3 and 4 occurred due to the loss of the 3A high head safety injection (HHSI) pump because it could not be powered from the faulted 3A 4kV bus with both Unit 4 HHSI pumps earlier (0624) removed from service due to planned maintenance. This caused three of the four HHSI pumps to be inoperable. The four HHSI pumps are shared by both Units 3 and 4. The safety function is achieved by two of the four HHSI pumps. Both Unit 4 HHSI pumps were restored to operable status at 1336. The loss of safety function is reportable in accordance with 10 CFR 50.72(b)(3)(v)(D).

“The Unit 3 reactor is stable in Mode 3. The 3A 4kV bus remains deenergized until troubleshooting and repairs are complete. Unit 4 remains operating at 100% power.”

The licensee will notify the NRC Resident Inspector.

Notified R2DO (Ehrhardt) and NRR EO (Miller).

Source: NRC  Event Number:  52623


Media Report

TV: Explosion hits US nuclear plant — Officials declare emergency alert — “Fire shuts down reactor” — Gov’t conducting special investigation, possible “serious safety consequences” — “Atmospheric steam dumps” required (VIDEO)

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