13 mai 2015
Alors que le réacteur était en arrêt froid pour rechargement de combustible, l’arrêt d’urgence s’est enclenché intempestivement. Les systèmes de protection du réacteur se sont enclenchés alors que le cœur n’était pas critique. L’opérateur affirme avoir déclaré "l’incident" par simple courtoisie pour l’Autorité de sûreté nucléaire américaine. Nous n’en saurons pas plus sur les effets concrets qu’à eu cette activation sur le réacteur dans une configuration non prévue.
Type : Fukushima I - Puissance : 2 028 MWth - Première divergence : 06/1972
Available in english only.
Event Number : 51174
Facility : PILGRIM - State : MA
Unit : [1] - RX Type : [1] GE-3
Event Date : 05/13/2015 : Event Time :
Emergency Class : NON EMERGENCY 10 CFR Section : INFORMATION ONLY
Initial PWR : 0 % - Current PWR : 0 % -
Event Text
VOLUNTARY REPORT - INFORMATION ONLY
"On May 13, 2015, with the unit shut down and the mode switch in Refuel, during the performance of plant procedure 3.M.2-12.4, ’Backfilling Reference Lines for Racks C2205, C2275, and C2251’ a full reactor scram occurred. The scram occurred at Step [26](b) of Attachment #1 of the procedure. The plant had been shut down for refueling for a couple of weeks or more and was in ’cold’ condition. This event was evaluated for potential reportability under both 10 CFR 50.72 and 50.73 and found to be not reportable as either a prompt report or LER. The following ’System Actuation’ sections were most applicable.
"10CFR50.72(b)(2)(iv)(B) Any event or condition that results in actuation of the reactor protection system (RPS) when the reactor is critical - Plant Response : Pilgrim was not critical at the time of the event.
"10CFR50.72(b)(3(iv)(A) Any event or condition that results in valid actuation of any of the systems listed in paragraph (b)(3)(iv)(B) - Plant Response : Pilgrim was in the process of refilling reference legs as part of restoration from the refueling outage. This was not a valid RPS signal.
"10CFR50.73(a)(2)(iv)(A) Any event or condition that resulted in manual or automatic actuation of any of the systems listed in paragraph (a)(2)(iv)(B) of this section, except when : (2) The actuation was invalid and ; (i) Occurred while the system was properly removed from service - Plant Response : This was an invalid actuation that occurred when the system was already properly removed from service. All requirements of plant procedures for removing equipment from service had been met. That included required clearance documentation, equipment and control board tagging and properly positioned valves and power supply breakers.
"Although this event is not reportable, we are making a courtesy notification to the NRC Operations Center."
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2015/20150624en.html#en51174
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