Hatch Nuclear Power Plant was forced to shutdown for 48 hours after a contractor updated software on a computer that was on the plant’s business network.  The computer was used to monitor chemical and diagnostic data from one of the facility’s primary control systems.  The software was designed to synchronize data on both systems.  When the updated computer rebooted, it reset the data on the control system to interpret the lack of data as a drop in water resevoirs that cool the plant’s radioactive nuclear rods.  The safety system triggered a shutdown. The engineer was not aware that the control system would be synchronized as well and that a reboot would reset the control system.

Power plant shutdown for 48 hours.