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Etats-Unis : Brunswick : démarrage automatique des 4 groupes diesels de secours du site




25 mars 2019


Le réacteur n°1 était à 100 % de sa puissance et le réacteur n°2 à 0 %. A 4h du matin, l’unité 2 était en cours d’alignement sur le bus d’alimentation d’urgence via le transformateur auxiliaire conformément aux procédures.
Une panne s’est produite lors de la manœuvre de commutation entre le 230 kV et les transformateur.Cette panne a engagé le démarrage de tous les groupes diesels d’urgence.

Type : Fukushima 1 (BWR Mark 1) - Puissance 2 923 MWth - Première divergence : n°2 : 03 / 1975- n°1 : 10 / 1976 -

Available in english only


Event Number : 53955

Facility : BRUNSWICK - Unit : [1] [2] - RX Type : [1] GE-4,[2] GE-4

Event Date : 03/25/2019 -Event Time : 04:02 [EDT]

Emergency Class : NON EMERGENCY
10 CFR Section :
50.72(b)(3)(iv)(A) - VALID SPECIF SYS ACTUATION

Initial PWR Current PWR
1 100 % - 100 %
2 0 % - 0 %

Event Text

AUTOMATIC START OF FOUR EMERGENCY DIESEL GENERATORS

"At 0402 Eastern Daylight Time (EDT) on March 25, 2019, an actuation of the four Emergency Diesel Generators (EDGs) occurred.
At the time of the event, Unit 1 was in Mode 1 at approximately 100% power and Unit 2 was in Mode 4 at 0% power. Unit 2 was in the process of aligning the electrical distribution system to power the emergency buses via the Unit Auxiliary Transformer (UAT) in accordance with plant procedures.
It was determined that a fault occurred on the power path between the 230 KV switchyard and the UAT. This caused a main generator differential lockout relay to actuate ; thereby starting the EDGs. All emergency buses remained energized from offsite power via the Startup Auxiliary Transformer and, therefore, the EDGs did not tie to their respective buses.
The EDGs responded per design to this event. This event is being reported in accordance with 10 CFR 50.72(b)(3)(iv)(A) as an event that results in valid actuation of the EDGs. Due to the shared configuration of the Brunswick electrical system, both Unit 1 and Unit 2 are affected.

"The Unit 2 main generator lockout was reset and the EDGs have been restored to standby condition. Troubleshooting activities to determine the cause of the fault are in progress.

"There was no impact on the health and safety of the public or plant personnel.

"The NRC Resident Inspector has been notified."

https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2019/20190326en.html