10 octobre 2013
Le circuit d’injection basse pression qui interviendrait en cas d’accident avec le réacteur en fonctionnement en basse pression a été déclaré inopérant suite à une alarme indiquant un débit de circulation insuffisant. Le capteur de débit aurait eu des difficultés à répondre en temps réel à la réalité du flux et le circuit a été déclaré opérationnel 6 h 38 après déclenchement de l’alarme.
Type : BWR Mark 2 - Puissance : 3 486 MWTh - Première divergence : 01/1984
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Facility : COLUMBIA GENERATING STATION - Region : WA Unit : [2] RX Type : [2] GE-5 -
Event Date : 10/10/2013 - Event Time : 08:09
Emergency Class : NON EMERGENCY 10 CFR Section : 50.72(b)(3)(v)(D) - ACCIDENT MITIGATION
Initial PWR : 100 % - Current PWR : 100 %
Event Text
LOW PRESSURE CONTAINMENT SPRAY DECLARED INOPERABLE
"At 0809 PDT on 10/10/2013, after starting Standby Service Water (SW) pumps, Columbia Generating Station (Columbia) received a flow low alarm for the Low Pressure Containment Spray (LPCS) pump motor cooling water. The flow indicator SW-FIS-19 was reported too low to support pump function. The LPCS system was declared inoperable, and the appropriate Technical Specification action statement was entered. The cause of the low flow alarm has not been determined. This event is reportable under criterion 10 CFR 50.72(b)(3)(v)(D) ’Any Event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to (D) Mitigate the consequences of an accident.’
"Columbia is continuing to troubleshoot and repair as appropriate to restore the SW flow to the LPCS pump.
"The licensee has notified the NRC Resident Inspector."
* * * UPDATE ON 10/11/13 AT 1653 EDT FROM MATT HUMMER TO DONG PARK * * *
"Subsequent to receipt of the low flow alarm, flushing of the flow indicating switch sensing lines was conducted. It has been determined that the instrument sensing lines are partially blocked providing a flow indication that is slow to respond to actual flow conditions. The flow is currently reading normally. The LPCS pump was declared operable on 10/10/13 at 1447 PDT. The initial notification incorrectly stated ’Low Pressure Containment Spray (LPCS)’, the correct description is ’Low Pressure Core Spray (LPCS)’."
The licensee has notified the NRC Resident Inspector.
Notified R4DO (Hay).
Event Number : 49425
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2013/20131017en.html#en49425
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