SAN ONOFRE (CBS News 8) - A massive nuclear reactor vessel head containing low-level radioactive waste left the San Onofre nuclear power plant shortly after 9pm Monday, bound for a disposal facility about 80 miles west of Salt Lake City, Utah.
Southern California Edison said shipping what is known as "Class-A" low-level radioactive waste, like in this case, is a relatively frequent occurrence for hospitals, universities and nuclear plants, but because of the considerable size of this vessel head, they felt it important to alert the public.
The 77-ton nuclear reactor vessel head, loaded onto a tractor trailer, pulled out of the San Onofre nuclear generating station Monday night, getting on to Interstate 5 north as it begins a three-day journey to a nuclear waste disposal facility in Clive, Utah.
"It's a fairly sizeable component that will be moving along major interstates," said Maureen Brown, spokesperson for Southern California Edison.
Southern California Edison says these transports have been safely completed many times, with no threat to the public.
"There is no measurable radiation exposure," Brown said. "The transport of this material is regulated and very closely monitored."
Standing roughly six feet away from this vessel head for one hour would equal the same radioactive exposure as a dental X-ray, according to Southern California Edison.
"This particular shipment would be less than 1 millirem per hour," Brown added.
To put that in perspective, that is the same amount of radiation exposure by watching television for one year.
Flying across the country round-trip exposes you to 3 to 5 millirems of radiation, while living in a home made of adobe, stone or brick in a year's time exposes you to approximately 7 millirems of radiation, according to Southern California Edison.
Over the past three years, San Onofre has safely shipped massive steam generators weighing about 350 tons to the same site in Utah.
This shipment that began Monday night will also follow all state transportation regulations, meaning here in California it can only be on the roads during the night, while in Nevada and Utah, it is only allowed to travel in the daytime.