31 janvier 2014
Les opérateurs déroulent les opérations d’arrêt obligatoire du réacteur suite à la perte de l’alimentation électrique de 480 V qui alimente les groupes de chauffage du pressuriseur. Le groupe électrogène B est indisponible suite à l’exécution de sa maintenance programmée.
Type : PWR - Puissance thermique : 2 700 MWTh - Première divergence : 10 1975
Available in english only.
Event Number : 49779 - Facility : MILLSTONE - 1 State : CT
Unit : [2] -RX Type : [2] CE
Event Date : 01/31/2014 - Event Time : 03:30
Emergency Class : NON EMERGENCY 10 CFR Section : 50.72(b)(2)(i) - PLANT S/D REQD BY TS
Initial PWR 100 % Current : 0 %
Event Text
TECHNICAL SPECIFICATION REQUIRED SHUTDOWN DUE TO DEGRADATION OF THE PRESSURIZER PROPORTIONAL HEATERS GROUP 1
Operators commenced a Technical Specification required shutdown due a 480 volt supply breaker trip resulting in degradation of the Pressurizer Proportional Heaters Group 1. The licensee plans on making a containment entry to investigate the cause of the breaker trip.
The B-Emergency Diesel-Generator is currently inoperable for planned maintenance. Unit 2 is currently ramping down and proceeding to a shutdown. The plant is in a normal electrical configuration. There is no indication of any primary to secondary leakage. Unit 3 is unaffected.
The licensee notified the NRC Resident Inspector.
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2014/20140203en.html