According to an Event Report posted on the NRC website on Friday:
At 0942 on May 25, 2014, the Cook Nuclear Plant (CNP) declared both Control Room Emergency Ventilation trains inoperable … due to an inoperable Control Room Envelope when a control room boundary door was identified as not latching correctly during a security door check.
What could have gone wrong? According to the report:
The latch would not have been able to maintain the door closed during an event resulting in Control Room Pressurization.
In either a badly-written sentence or a bizarre promise that current action could have mitigated an accident occurring in the past, the report asserts:
At this time, Security established a continuous door post and would have been able to maintain the door closed.
As always, you can view Event Notification Reports at www.nrc.gov.