The FAA issued temporary flight restrictions at this plant on June 7, 2011. Unlike Ft. Calhoun, the plant was not listed as the location site so this went unnoticed until the notification of the event was issued.
The information above can be found at: tfr.faa.gov/save_pages/detail_1_6704.html.
The plant’s location can be verified against the FAA document by clicking here. The reason for the restrictions is to prevent hovering aircraft from hitting high voltage power lines. Since Ft. Calhoun is offline, the power lines are not energized but it is possible that a helicopter pilot may want to fly into transmission lines. Using this logic, all nuclear plants should be under these same restrictions.