4 janvier 2018
C’est une ligne de 345 000 volts qui est tombée alors que le réacteur était à près de 100 % de sa puissance, puissance qui a alors été réduite à 81 % puis l’arrêt d’urgence a été engagé. Toutes les barres de contrôle se sont introduites dans le coeur. Le niveau de liquide de refroidissement a baissé et il a alors été rétabli tout comme le confinement. Le signal du système de protection a lui aussi été réinitialisé. Après l’arrêt d’urgence la pompe de contrôle des barres de contrôle est tombée suite à une pression d’aspiration faible.La pompe de l’autre voie a alors été mise en service. Les autres systèmes d’arrêt ont opéré correctement. Les diesels de secours ont pris le relais de l’alimentation de secours.
Type : Fukushima 1 (BWR Mark 1) - Puissance : 2 021 MWth - Première divergence : 06 / 1972 -
Available in english only
Event Number : 53147
Facility : PILGRIM - State : MA
Unit : [1] - RX Type : [1] GE-3
Event Date : 01/04/2018 - Event Time : 14:10 [EST]
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 : 81 % Current PWR : 0 %
Event Text MANUAL REACTOR SCRAM DUE TO PARTIAL LOSS OF OFFSITE POWER DURING WINTER STORM
"On January 4, 2018, at 1410 hours EST, with the reactor at approximately 100 percent power and steady state conditions, the winter storm across the Northeast caused the loss of offsite 345 kV Line 342. Reactor power was reduced to approximately 81 percent and a procedurally required manual reactor scram was initiated. All control rods fully inserted.
"As a result of the reactor scram, indicated reactor water level decreased, as expected, to less than +12 inches resulting in automatic actuation of the Primary Containment Isolation Systems for Group II - Primary Containment Isolation and Reactor Building Isolation System, and Group VI - Reactor Water Cleanup System.
"Reactor Water Level was restored to the normal operating band. The Primary Containment Isolation Systems have been reset. The Reactor Protection System signal has been reset.
"Following the reactor scram, the non-safety related Control Rod Drive Pump "B" tripped on low suction pressure. Control Rod Drive Pump "A" was placed in service. All other systems operated as expected, in accordance with design.
"This event is reportable per the requirements of Title 10, Code of Federal Regulations (CFR) 50.72 (b)(2)(iv)(B) - "RPS Actuation" and 10 CFR 50.72 (b)(3)(iv)(A) - "Specified System Actuation."
"This event had no impact on the health and/or safety of the public.
"The NRC Resident Inspector has been notified."
The main steam isolation valves are open with decay heat being removed via steam to the main condenser.
Offsite power is still available from 345kV line 355. As a contingency, emergency diesel generators are running and powering safety busses per licensee procedure.
The licensee notified the Commonwealth of Massachusetts. The licensee will be notifying the town of Plymouth as part of their local notifications. The licensee will be issuing a press release.
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2017/20171024en.html
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