On April 16, 2011, an EF3-rated tornado touched down in the switchyard of the Surry nuclear power station in Virginia, damaged equipment and severed off-site electric pow-er. The station shut down automatically and back-up diesel generators started immediate-ly to provide electricity to maintain both units in a stable condition. The National Weather Service reported that the tornado had a “nearly continuous damage path ranging from around 200 yards to as much as a half mile wide.” Over 200 homes were damaged and numerous trees were downed or sheared. 

Three waves of storms in the Southeast on April 26 and 27 generated an un-precedented 226 tornadoes in a 24-hour period. These tornadoes killed ap-proximately 330 people, obliterated entire towns and devastated the Tennessee Valley Authority (TVA) transmission system in this region. TVA’s Browns Ferry reactors in Alabama suffered a loss of off-site power when the storm damaged the station’s transmission lines. The layers of protection for nuclear units en-sure that even though the station had diverse off-site power feeds, the next

layer of defense, the emergency diesel generators, were available when the unlikely combination of storms occurred. Due to the extensive damage to the transmission system (337 damaged structures, 96 lines out of service) off-site power was not restored for five days. All three reactors shut down safely and were maintained in safe shutdown condition during this period.