The steam generator is one of four replaced at San Onofre Nuclear Generating Station as part of a $6.7 million project that includes funding to haul away the old technology.
"In the original design they were targeted for 30 year useful life," said Pete Dietric, a senior vice president at Southern California Edison. "Back in the 1990s San Onofre Southern California identified right around the 2011 would be the end of useful life for the steam generator."
The nearly 400-foot-long trailer sits on 192 wheels that will evenly distribute the generator's weight and protect the roadways on its 832-mile journey.
Project managers also carefully mapped out a route along interstates 5 and 15 through San Diego, Riverside and San Bernardino counties.
"Some of the bridges in California cannot handle the total weight of this, so we have to find a route that allows to pass over the bridges that can handle this amount of weight," senior project manager Craig Harbets said.
The California Highway Patrol will escort the massive trailer. At a top speed of 15 miles per hour, it will take three weeks to get it to its final destination.
This will be the first of four shipments that will be headed to Utah, but for security reasons they are not saying when the mammoth-size load will be hitting the road.