25 mai 2014
Pendant la mise à l’arrêt du réacteur pour réparer une fuite sur une vanne à l’intérieur de l’enceinte de confinement (alors que le réacteur était à 19 % de sa puissance nominale), une perte de vide au condenseur est survenue.
Type : PWR - Puissance : 2 300 MWTh - Première divergence : 06/1973
Available in english only.
La cause de cette perte est en cours de recherche.
L’arrêt s’est effectué normalement par les systèmes de protection du réacteur activés suite à un cœur critique sans activation des systèmes de sécurité.
L’évacuation s’effectue par les décharges de vapeur à l’atmosphère et il n’y a pas connaissance de fuite primaire / secondaire.
Event Number : 50140
Facility : TURKEY POINT - Region : 2 State : FL - Unit : [4], type W-3-LP
Event Date : 05/25/2014 - Event Time : 05:36
Emergency Class : NON EMERGENCY 10 CFR Section : 50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL
Initial PWR : 19 % - Current PWR : 0 %
Event Text
AUTOMATIC REACTOR TRIP DUE TO TURBINE TRIP ON LOSS OF CONDENSER VACUUM
"This is an non-emergency event notification to the NRC Operations Center in accordance with 10 CFR 50.72(b)(2)(iv)(B) for a valid actuation of the reactor protection system (RPS) (four hour notification).
"On 05/25/2014 at 0536 EDT, as part of a planned maintenance outage to repair a leaking check valve inside the containment building, Unit 4 power level had been lowered to 19% reactor power for the planned opening of the reactor trip breakers. Unit 4 experienced a loss of condenser vacuum. An automatic turbine trip signal was generated which initiated a reactor trip signal. The reactor tripped as required on the automatic trip signal. Unit 4 is currently in Mode 3 and stable. The loss of vacuum is under investigation at this time. All other plant systems are working as designed."
The reactor trip was uncomplicated with no other safety system actuations. Decay heat is being removed via steam dumps to atmosphere. There is no known primary to secondary leakage. The grid is stable and Unit 4 is in its normal shutdown electrical lineup. Unit 3 was not affected and continues to operate at 100% power.
The licensee has notified the NRC Resident Inspector.
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2014/20140527en.html#en50140