The Federal Emergency Management Agency will see how well state and local officials respond to an emergency at the nuclear facility in southeastern Virginia.
They got some real-life experience last April, when tornadoes knocked out power to two of the plant's reactors, which then automatically shut down.
Officials with Virginia Dominion Power, which owns the plant, said no one was injured and the reactors were not damaged.
FEMA will present preliminary findings of this week's drill on July 22. The evaluation also will be sent to the Nuclear Regulatory Commission for use in licensing decisions