Réseau Sortir du nucléaire
BoutiqueAgendaFaire un donEN

Des accidents nucléaires partout

Image / illustration
Etats-Unis : Sequoyah : Chute du générateur principal qui a entraîné l’arrêt de la turbine qui a elle-même arrêté le réacteur

24 juillet 2015

Le système de refroidissement auxiliaire a pris le relais et l’arrêt se serait passé sans problème. L’origine du problème est en cours de recherche.

Type : PWR - Puissance : 3 455 MWth - Première divergence : 07/1980

Available in english only.

Event Number : 51259

Facility : SEQUOYAH - State : TN

Unit : [1] - RX Type : [1] W-4-LP

Event Date : 07/24/2015 - Event Time : 13:51

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

Initial PWR : 100 % - Current PWR : 0 %

Event Text


"At 1351 EDT on 7/24/2015, Sequoyah Unit 1 reactor/turbine automatically tripped.

"Following the reactor trip, all safety-related equipment operated as designed. Auxiliary Feedwater automatically initiated as expected from the Feedwater Isolation Signal.

"Unit 1 is currently being maintained in Mode 3 at NOT/NOP, approximately 548 F and 2235 psig, with auxiliary feedwater supplying the steam generators and decay heat removal via the condenser steam dumps. The immediate cause of the trip was an electrically-induced turbine trip. There was no associated work in progress related to this and all systems were normally aligned.

"There is no indication of any primary/secondary leakage. All rods fully inserted on the reactor trip and remain inserted. The electrical alignment is normal with shutdown power supplied from off-site power. The 2B-B Emergency Diesel Generator is currently in service for the performance of an unrelated surveillance. There is no operational impact to Unit 2. Unit 2 continues to operate in Mode 1 at 100%.

"There was no impact on public health and safety. Post-trip investigation is in progress and planned restart timeline has not yet been determined.

"The licensee notified the NRC Resident Inspector."