25 mars 2014
Suite à une baisse du débit de vapeur, alors que le réacteur était à 85 % de sa puissance nominale (Pn), l’équipe de conduite a engagé une procédure d’arrêt normal du réacteur. Quand la puissance a atteint 46 % de la Pn, la pression était de 0,8 bar et l’arrêt d’urgence du réacteur a du être enclenché manuellement. Le cœur étant critique, les systèmes de protection du réacteur se sont enclenchés.
Type : BWR Mark 3 - Puissance : 3 473 MWth - Première divergence : 02/1987
Available in english only.
Event Number : 49958 - Facility : CLINTON - State : IL
Unit : [1] - RX Type : [1] GE-6 -
Event Date : 03/25/2014 - Event Time : 19:42
Emergency Class : NON EMERGENCY 10 CFR Section : 50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL
Initial PWR : 46 % Current PWR 0 %
Event Text
MANUAL REACTOR SCRAM DUE TO LOSS OF CONDENSER VACUUM
"The plant was stable at 85 percent power when off-gas flow started lowering. The operating crew entered the loss of vacuum off-normal procedure and commenced an emergency power reduction to attempt to slow/halt the loss of vacuum while attempting various prescribed actions in the off-normal procedure. When vacuum reached 24 in. Hg, a rapid plant shutdown was performed as prescribed in the off-normal procedure. Power was at 46 percent when a rapid plant shutdown was commenced with the mode switch placed in shutdown at 1942 CDT. All control rods fully inserted on the scram, no emergency core cooling system injected or was required, no safety/relief valve(s) lifted and all systems responded as expected on the scram. The plant will remain in mode 3 with normal makeup from the feedwater system and pressure control on the turbine bypass valves with the main condenser available as a heat sink. All vital and non-vital electrical busses are powered from reserve off-site sources and no emergency diesel generators started on the scram. The cause of the loss of vacuum is under investigation."
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2014/20140326en.html