
An AFP report said that the contract worker had been arrested and interviewed by police but released. Authorities felt the man did not know the device was in his truck.
In a statement, APS Executive Vice President and chief nuclear officer Randy Edington said, "Our entire staff - and in particular our security officers - responded appropriately and professionally to this event."
The security alert was ended at 3pm the same day, from which time APS said it would resuming normal activities at the plant. Palo Verde is home to three operating pressurized water reactors and supplies about 3800 MWe. Power generation at the plant was not disturbed.
The Federal Bureau of Investigation (FBI) is handling the matter with APS's cooperation.
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