From AP and Drudge Report:
There aren't any more details right now. I'll update this later as more comes out. Malkin has more.
Security officials at the nation's largest nuclear power plant detained
a contract worker with a small explosive device in the back of his
pickup truck Friday, authorities said.
The worker was stopped and detained at the entrance of the Palo Verde
Nuclear Generating Station, said U.S. Nuclear Regulatory Commission
spokesman Victor Dricks. Security officials then put the nuclear
station on lockdown, prohibiting anyone from entering or leaving the
facility.
Authorities described the device as a small capped pipe that contained suspicious residue.
[...]
The incident was considered an "unusual event"—the lowest of four
emergencies the plant can declare, said Jim Melfi, an inspector with
the U.S. Nuclear Regulatory Commission.
There aren't any more details right now. I'll update this later as more comes out. Malkin has more.