23 avril 2015
L’impossibilité d’ouverture de deux soupapes de vapeur sur le circuit secondaire est à l’origine du problème. Les barres de contrôle se seraient correctement insérées et la chaleur du cœur évacuée par les générateurs de vapeur. Il n’y aurait pas eu de relâchement de radioactivité suite à la survenue de ce problème.
Type : PWR - Puissance : - 3 468 MWTh - Première divergence : 03/1978
Available in english only.
Event Number : 51004
Facility : COOK - 3 State : MI -
Unit : [2] - RX Type : [2] W-4-LP
Event Date : 04/23/2015 - Event Time : 02:10
10 CFR Section : 50.72(b)(2)(i) - PLANT S/D REQD BY TS 50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL 50.72(b)(3)(iv)(A) - VALID SPECIF SYS ACTUATION
Initial PWR : 2 % Current PWR : 0%
Event Text
MANUAL REACTOR TRIP DUE TO A SECONDARY PLANT TRANSIENT
"On April 23, 2015 DC Cook Unit 2 Reactor was manually tripped due to an uncontrolled cooldown due to two (2) failed open steam dump valves. The cause of the failure is still under investigation.
"This event is reportable under 10 CFR 50.72(b)(2)(i) Tech Spec Required Shutdown, as a four (4) hour report ; 10 CFR 50.72(b)(2)(iv)(B), Reactor Protection System (RPS) actuation, as a four (4) hour report ; and under 10 CFR 50.72(b)(3)(iv)(A), specified system actuation of the Reactor Protection System (RPS), as an eight (8) hour report.
"The electrical grid is stable and Unit 2 continues to be supplied by offsite power. All control rods fully inserted. Decay heat is being removed via steam generator Power Operated Relief Valves due to steam dump valves being manually isolated. Preliminary evaluation indicates all plant systems functioned normally following the Reactor Trip. DC Cook Unit 2 remains stable in Mode 3 while conducting the post Trip Review. No radioactive release is in progress as a result of this event.
"The DC Cook Resident NRC Inspector has been notified."
There is no indication of primary to secondary leakage and there is no impact on Unit 1.
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2015/20150424en.html#en51004