1er octobre 2015
Sur le réacteur n° 1, la fonction de sécurité de déclenchement de la turbine avait été neutralisée sur les deux voies comme si le réacteur était en mode 4. Or le réacteur est passé, à ce moment là, en mode 3 avec les deux voies de déclenchement hors service, ce qui est contraire aux spécifications techniques puisque la fonction d’atténuation d’un accident aurait été inopérante.
Type : PWR - Puissance : 3 587 MWth - Première divergence : 02/1985
Available in english only.
Event Number : 51436
Facility : BYRON
State : IL Unit : [1]
RX Type : [1] W-4-LP
Event Date : 10/01/2015 - Event Time : 09:06
Emergency Class : NON EMERGENCY 10 CFR Section : 50.72(b)(3)(v)(D) - ACCIDENT MITIGATION
Initial PWR : 0 % - Current PWR : 0 % -
Event Text
MODE CHANGE WITH TURBINE TRIP LEADS LIFTED
"At 0906 [CDT], it was determined that U1 [Unit 1] was in a condition that could have prevented fulfillment of the turbine trip safety function and TS [Tech Spec] 3.0.3 was entered. Leads had been lifted to disable the turbine trip function on both SSPS [Solid State Protection System] trains while U1 was in Mode 4 (which is outside the mode of applicability). However, at 0059 [CDT], U1 entered Mode 3 with these leads still lifted. In Mode 3, both trains of the turbine trip function are required to be operable per TS 3.3.2. The turbine was subsequently tripped at 0932 [EDT] and the leads were re-landed enabling the turbine trip function at 0946 [CDT], TS 3.0.3 was subsequently exited. This condition is being reported in accordance with 10 CFR 50.72 (b)(3)(v)(D) for an event or condition that could have prevented the fulfillment of a safety function to mitigate the consequences of an accident.
"The Byron NRC site Resident Inspector has been notified of this condition."
The licensee has notified the State of Illinois.
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2015/20151002en.html#en51436