18 octobre 2017
Une vanne qui aurait dû être fermée en temps normal puis ouverte sur ordre d’injection de sécurité n’était pas dans son état initial. Ce circuit n’étant pas doublé par un deuxième de secours, le réacteur doit entrer en phase de limitation de puissance de fonctionnement (Limiting Condition for Operation - LCO - )
Type : Fukushima 1 (BWR Mark1) - Puissance : 2 419 MWth - Première divergence : 2 / 1974 -
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Event Number : 53022
Facility : COOPER - State : NE
Unit :  - RX Type :  GE-4
Event Date : 10/18/2017 - Event Time : 02:09 [CDT]
Emergency Class : NON EMERGENCY 10 CFR Section : 50.72(b)(3)(v)(D) - ACCIDENT MITIGATION
Initial PWR : 100 % - Current PWR : 100 % -
HPCI DECLARED INOPERABLE
"Eight hour report due to HPCl [High Pressure Coolant Injection] inoperability.
"HPCl valve operability testing was performed on October 18, 2017. Following satisfactory completion of opening stroke timing, the control switch for HPCI-MOV-MO19, HPCI Injection Valve, was taken to close. The valve indicates that it moved to an intermediate position, but it has not indicated that it has fully closed. This resulted in the valve being declared inoperable. This valve is normally closed and automatically opens on a HPCI initiation signal.
"HPCl was previously declared inoperable at time 0136 [CDT] on October 18 for surveillance testing. Entry was made into Tech Spec LCO 3.5.1 Condition C - HPCI System Inoperable at that time. Required Actions for Condition C are to verify by administrative means RCIC System is operable within 1 hour and restore HPCI System to operable status within 14 days. RClC was verified operable by administrative means concurrent with declaration of HPCI inoperable.
"Troubleshooting activities for HPCI are being planned.
"HPCI is a single train safety system. This report is submitted as a condition that at time of discovery could prevent the fulfillment of the safety function of an SSC [structures, systems, and components] needed to mitigate the consequences of an accident.
"This condition has been entered into the CNS Corrective Action Program."
The licensee notified the NRC Resident Inspector.