CLINTON -- There was no emergency at the Clinton Power Station Wednesday morning, but there could have been based on the number of state, county and local emergency crews in DeWitt County.

And that's just what organizers wanted: Real-life practice for those who would need to respond in case of a real disaster.

An estimated 700 people took part, both on site and in emergency response centers as far away as Warrenville and Springfield. Jerry DeYoung of Exelon's emergency preparedness team was in charge.

"We very much appreciate the excellent response we had. The drill went very well, and it's because the agencies' support that we were able to have the success today that we hoped for," said DeYoung.

The drill was a practice run for 2011, when drills will be graded by the Federal Emergency Management Agency and the Illinois Nuclear Regulatory Agency. It was the last of six practice tests over the past three years.

"The lessons learned from the pilot drills will help guide the structure of the real testing when it starts in 2011," said Bill Harris, the station's communications manager.

The drill began at 8:45 a.m. with a mock plane crash near the power station. Crews from at least 15 agencies, from the FBI to local fire volunteers, responded. Work was centered at a site that had a McLean County mobile command post and a state communication vehicle.

Among agencies taking part were FEMA; U.S. Nuclear Regulatory Commission; FBI; Illinois Emergency Management Agency; Illinois Department of Natural Resources; DeWitt County Sheriff's Department; Decatur Police Department; emergency management agencies from DeWitt, Macon, McLean and Piatt counties; Clinton Ambulance; and fire departments from Clinton, Maroa, Kenney and Farmer City.

The exercise wound down just after 1 p.m. and was followed by a debriefing.

All nuclear power stations must conduct yearly emergency tests and they are graded every other year by state and federal agencies. Clinton has a graded exercise scheduled Nov. 18.