By Brian Krebs
washingtonpost.com Staff Writer
June 5, 2008
A nuclear power plant in Georgia was recently forced into an emergency
shutdown for 48 hours after a software update was installed on a single
The incident occurred on March 7 at Unit 2 of the Hatch nuclear power
plant near Baxley, Georgia. The trouble started after an engineer from
Southern Company, which manages the technology operations for the plant,
installed a software update on a computer operating on the plant's
The computer in question was used to monitor chemical and diagnostic
data from one of the facility's primary control systems, and the
software update was designed to synchronize data on both systems.
According to a report filed with the Nuclear Regulatory Commission, when
the updated computer rebooted, it reset the data on the control system,
causing safety systems to errantly interpret the lack of data as a drop
in water reservoirs that cool the plant's radioactive nuclear fuel rods.
As a result, automated safety systems at the plant triggered a shutdown.
Southern Company spokeswoman Carrie Phillips said the nuclear plant's
emergency systems performed as designed, and that at no time did the
malfunction endanger the security or safety of the nuclear facility.
Phillips explained that company technicians were aware that there was
full two-way communication between certain computers on the plant's
corporate and control networks. But she said the engineer who installed
the update was not aware that that the software was designed to
synchronize data between machines on both networks, or that a reboot in
the business system computer would force a similar reset in the control
"We were investigating cyber vulnerabilities and discovered that the
systems were communicating, we just had not implemented corrective
action prior to the automatic [shutdown]," Phillips said. She said plant
engineers have since physically removed all network connections between
the affected servers.
Computer security experts say the Hatch plant incident is the latest
reminder of problems that can occur when corporate computer systems at
the nation's most critical networks are connected to sensitive control
systems that were never designed with security in mind.
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