20 juillet 2015
Alors que le réacteur était à 100 % de sa puissance, le confinement secondaire a diminué en dessous des spécifications techniques. Les deux trains de traitement de gaz radioactifs ont été mis en route et le bâtiment réacteur a été isolé. Des ouvriers qui travaillaient à l’entretien du toit sont à l’origine de création d’ouvertures. Du compte-rendu de la NRC, on note donc que des travailleurs opéraient sur un réacteur à 100 % de sa puissance et créaient des trous dans ce qui est censé être l’ultime enceinte en béton de protection des riverains et de l’environnement ! Les travailleurs ont été arrêtés dans leur tâche afin de rétablir le confinement.
Type : Fukushima 1 (BWR Mark1) - Puissance : 2 536 MWth - Première divergence : 11/1974
Available in english only.
Event Number : 51242
Facility : FITZPATRICK - State : NY
Unit : [1] - RX Type : [1] GE-4
Event Date : 07/20/2015 - Event Time : 07:40
Emergency Class : NON EMERGENCY 10 CFR Section : 50.72(b)(3)(v)(C) - POT UNCNTRL RAD REL
Initial PWR : 100 % - Current PWR : 100 %
Event Text
TEMPORARY LOSS OF DIFFERENTIAL PRESSURE IN SECONDARY CONTAINMENT
"On the morning of July 20, 2015 at 0740 EDT, with James A. FitzPatrick Nuclear Power Plant (JAF) operating at 100 percent power, the Secondary Containment differential pressure decreased below the JAF Technical Specification (TS) Surveillance Requirement (SR-3.6.4.1.1) value of greater than or equal to 0.25 inch of vacuum water gauge. Both trains of the Standby Gas Treatment System were placed in service and the Reactor Building was isolated. The decrease in Secondary Containment differential pressure was caused by Reactor Building roof maintenance creating multiple openings. Maintenance workers were immediately ordered to stop work and address the condition. Secondary Containment differential pressure was restored to within the TS SR value at 0915 EDT, and remains greater than 0.25 inch of vacuum water gauge.
"The secondary containment is a structure that surrounds the primary containment and is designed to provide secondary containment for postulated loss-of-coolant accidents inside the primary containment. To prevent exfiltration the secondary containment requires the control volume pressure at less than the external pressure. The differential pressure requirement of TS SR-3.6.4.1.1 ensures that the secondary containment boundary is sufficiently leak tight to preclude exfiltration. During this period there were no unmonitored radioactive releases ; however, this event could have prevented the fulfillment of a safety function to control the release of radioactive material and it is reported pursuant to 10 CFR 50.72(b)(3)(v)(C)."
The NRC Resident Inspector has been informed.
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2015/20150721en.html#en51242