28 mars 2019
La fuite supérieure à 2,3 m3/h a été constatée avec le réacteur à pleine puissance durant plus d’un quart d’heure. Conformément aux procédures, l’arrêt du réacteur a alors été engagé : 17 minutes après la découverte de la fuite, le réacteur est à 57 % de sa puissance. L’opérateur a également reçu une alarme pour une augmentation de la pression dans le sécheur.
70 minutes après le début du problème, le réacteur est encore à 37 % de puissance nominale, la pression dans le sécheur a été divisée par deux et l’arrêt est toujours en cours. 3 minutes plus tard l’ARRÊT d’URGENCE est enclenché.
Actualisation du 29 mars : 12 h 12 min après le début du problème, la fuite a été réduite à moins de 2,3 m3/h.
D’après ces données, on peut estimer que la perte de fluide primaire aurait été supérieure à 27 m3 ! Malgré cela, il n’y aurait pas eu d’élévation du niveau de radiations...
Type : Fukushima 1 (BWR Mark 1) - Puissance 2 923 MWth - Première divergence : n°2 : 03 / 1975- n°1 : 10 / 1976 -
Available in english only
Event Number : 53961
Facility : BRUNSWICK - State : NC
Unit : [1] - RX Type : [1] GE-4,
Event Date : 03/28/2019 - Event Time : 14:50 [EDT]
Emergency Class : UNUSUAL EVENT 10 CFR Section : 50.72(a) (1) (i) - EMERGENCY DECLARED
Initial PWR : 100 % Current PWR : 0 %
Event Text
UNUSUAL EVENT DECLARED DUE TO RCS UNIDENTIFIED LEAKAGE
At 1450 EDT on March 28, 2019, the licensee observed that the Unit 1 unidentified Reactor Coolant System (RCS) leakage was greater than 10 gallons per minute (gpm) for greater than or equal to 15 minutes. The licensee declared an Unusual Event in accordance with their EAL SU 5.1. The licensee initiated a unit shutdown in accordance with their procedures and the unit was approximately 58 percent reactor power at 1507 EDT, with unit shutdown in progress. The licensee also received an alarm due to increasing Drywell Pressure at 1.7 pounds drywell pressure.
At 1600 EDT the licensee called with an update. Unit 1 was still in an Unusual Event with the unit at 37 percent power with the shutdown continuing. Drywell Pressure had decreased to 0.8 pounds. At 1603 the licensee scrammed Unit 1.
Notified DHS SWO, FEMA Operations Center, DHS NICC, FEMA NWC (email), DHS Nuclear SSA (email), and FEMA NRCC SASC (email).
* * * UPDATE ON 3/28/2019 AT 1808 EDT FROM MARK TURKAL TO THOMAS KENDZIA * * *
"At 1437 EDT on March 28, 2019, with Unit 1 in Mode 1 at approximately 100 percent power, a Technical Specification-required shutdown was initiated due to indication of a leak in the drywell. Technical Specification Action 3.4.4.A, Unidentified Reactor Coolant System (RCS) leakage increase not within limit, requires RCS leakage to be reduced to within limits within 8 hours.
"It is expected that the leakage would not have been reduced to within limits within the required Technical Specification completion time ; therefore, this event is being reported in accordance with 10 CFR 50.72(b)(2)(i).
"There was no impact on the health and safety of the public or plant personnel.
"The NRC Resident Inspector has been notified."
* * * UPDATE ON 03/29/19 AT 0302 EDT FROM TOM FIENO TO BETHANY CECERE * * *
At 0259 EDT on March 29, 2019, the Unusual Event was terminated because RCS leakage was reduced to less than 10 gallons per minute. The most recent leakage rate measured at 0225 EDT was 3.9 gpm. The source of the leak will be identified when plant conditions allow containment entry. No elevated radiation levels were observed during this event. Drywell pressure is currently 0.0 psig. Unit 1 is in Mode 4.
The licensee notified the NRC Resident Inspector.
Notified R2DO (Bonser), NRR EO (Miller), IRD MOC (Grant), DHS SWO, FEMA Operations Center, DHS NICC, FEMA NWC (email), DHS Nuclear SSA (email), and FEMA NRCC SASC (email).
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2019/20190329en.html
La boutique
Informez vous