Semantic search

A worker failed to physically challenge the latch on the inboard reactor enclosure airlock door when traversing from the refuel floor into the reactor enclosure. The next worker to use the airlock opened the outboard door causing the inboard door to open due to differential pressure across the door. The outboard door was closed in less than 10 seconds. This event resulted in a brief inoperability of reactor enclosure secondary containment integrity.

The event was caused by a degraded airlock door self-closing feature on the inboard airlock door. A contributing cause was a worker failure to verify that the inboard airlock door was latched fully closed. The worker failed to properly use the self-check fundamental. The airlock doors were immediately closed to restore reactor enclosure secondary containment integrity and the degraded door self-closing feature was repaired. The worker was coached regarding use of the self-check fundamental. The lessons learned were communicated to the site.