The retired sections are considered low-level nuclear waste. Each one, weighing 750,000 pounds apiece, is to be shipped to a radioactive waste-disposal site near Clive, Utah.
"It emits some radiation but very, very low levels. An example would be, you and I are standing close to it right now. If we stood here for an hour we would receive no more radiation than a typical dental X-ray," said Gil Alexander, a San Onofre Nuclear Generating Station spokesman.
The section of generator sits on a road outside the nuclear plant. Officials say to move it, a special trailer will be built around it. The vehicle will have nearly 200 tires in order to evenly distribute weight to try to prevent highway damage.
Caltrans is checking the height and weight limits of bridges to make sure they can handle the load.
Officials will not reveal the exact route for security reasons, only saying the generator will travel through San Diego, Riverside and San Bernardino counties on its way to Utah beginning this month.
"We know there's always room for human error in any situation, there's lots of concerns around moving nuclear waste, but I'm sure they've done a lot of research into this and we can only hope that everything goes smoothly," said Gary Headrick, San Clemente Green.
Officials say the first section will travel at 15 miles per hour, moving on California highways only at night. It will take about three weeks to reach Utah.
Each section will travel the 800 miles, one at a time. Officials expect all four to be moved by the end of December.