31 mai 2015
Un arrêt turbine s’est également produit ce qui a activé l’arrêt d’urgence du réacteur. Le fonctionnement des barres de contrôle et des pompes auxiliaires se seraient déroulé normalement. Les niveaux de liquides dans les générateurs de vapeur auraient été rétablis. Suite à l’arrêt, les réchauffeurs d’alimentation en eau ne se sont pas enclenchés. Une remise à zéro de ces derniers a permis de sécuriser l’alimentation en eau par la pompe principale.
Type : PWR - Puissance : 1 677 MWth - Première divergence : 12/1973
Available in english only.
Event Number : 51107
Facility : PRAIRIE ISLAND - 3 State : MN
Unit : [1] - RX Type : [1] W-2-LP
Event Date : 05/31/2015 - Event Time : 22:20
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 RX : 100 % Current RX : 0 %
Event Text
MANUAL REACTOR TRIP DUE TO TRIP OF CONDENSATE AND MAIN FEEDWATER PUMP
"On May 31, 2015 at 2220 CDT, the Unit 1 reactor was manually tripped while operating at 100 percent power due to a lockout trip of 11 Condensate Pump followed by a lockout trip of 11 Main Feedwater Pump. Manual Reactor Trip is directed by the annunciator response procedure for the lockout alarm, C47010-0101, 11 Feedwater Pump Locked Out. This also resulted in a turbine trip. The crew entered the reactor trip emergency operating procedures and stabilized the unit in Mode 3 at normal operating pressure and temperature. All control rods fully inserted into the core following the trip. The manual trip is reportable per 10 CFR 50.72(b)(2)(iv)(B). The Auxiliary Feedwater System actuated to start the auxiliary feedwater pumps as designed on low narrow range steam generator level and provided makeup flow to the steam generators. The auxiliary feedwater actuation is reportable per 10 CFR 50.72(b)(3)(iv)(A). Steam generator levels have been returned to normal.Following the reactor trip, 15A Feedwater Heater relief lifted and failed to reseat. 12 Main Feedwater Pump was subsequently secured resulting in 15A Feedwater Heater relief valve reseating successfully . Steam generators are being supplied by 12 Motor Drive Auxiliary Feedwater Pump and decay heat is being removed by the condenser steam dump system. The cause of 11 Condensate Pump trip remains under investigation. There was no effect on Unit 2 as a result of this trip. The health and safety of the public and site personnel were not at risk at any time during this event. The NRC Senior Resident Inspector has been notified."
Unit 2 is unaffected and remains at 100 percent power.
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2015/20150601en.html#en51107
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