3 mai 2015
C’est à 22 % de la puissance du réacteur que la montée rapide du niveau d’eau dans un générateur de vapeur a entrainé cette série d’évènements. La vanne de régulation d’alimentation en eau de ce générateur de vapeur s’est ouverte à 80 % provoquant sa suralimentation. L’équipe de commande a alors lancé l’arrêt manuel du réacteur. L’alimentation en eau auxiliaire s’est alors enclenché automatiquement en réponse à l’isolation de l’eau de refroidissement.
Type : PWR - Puisssance : 3585 MWth - Première divergence : 05 / 1985 -
Available in english only
Event Number : 51036
Facility : WOLF CREEK - State : KS -
Unit : [1] - RX Type : [1] W-4-LP
Event Date : 05/03/2015 - Event Time : 10:22
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 PWR : 22 % - Current PWR : 0 % -
Event Text
FEEDWATER ISOLATION, TURBINE TRIP AND MANUAL REACTOR TRIP DURING POWER ASCENSION
"On 5/3/2015 during power ascension following Refueling Outage 20, Steam Generator ’C’ water level increased rapidly, causing a Feedwater isolation on high Steam Generator water level and an associated Turbine trip. The reactor was subsequently manually tripped.
"At the start of the event, reactor power was approximately 22%. Plant staff was in the process of transferring from Main Feedwater Bypass Feed Regulating Valve control, used for low power control, to Main Feedwater Regulating Valve control as part of power ascension. When the Main Feedwater Regulating Valve for ’C’ Steam Generator (AEFCV-530) was opened, it went to about 80% open, causing an overfeed of the ’C’ Steam Generator. High Steam Generator water level in ’C’ Steam Generator initiated an automatic Feedwater Isolation Signal, automatic Turbine Trip and automatic trip of the operating main feed pump. The operating crew initiated a manual reactor trip.
"The Auxiliary Feedwater System automatically initiated as part of the plant response to the feedwater system transient.
"The plant is presently stable in Mode 3. All equipment functioned normally, except the ’C’ Main Feedwater Regulating Valve (AEFCV0530) which did not function to properly control Steam Generator level. This valve did function as designed to close on the Feedwater Isolation Signal.
"NRC Resident Inspector has been contacted."
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2015/20150504en.html#en51036