WAYNESBORO, Ga. -- Contractors will raise the first above-ground structure Friday at the site of the nation's two newest nuclear reactors in 30 years.

The erection of a single, concrete support for one of Plant Vogtle's reactor cooling towers is a significant milestone in the $14 billion project because work for the last two years has been on the foundations of the various buildings, according to Mark Rauckhorst, vice president of construction for Southern Nuclear, the operators of the plant.

The structures that will house the reactor and its containment building required excavating 90 feet into the earth before concrete, steel and more dirt could be put back and then built upon. The volume of dirt moved could have built the Great Pyramid of Giza in Egypt six times.

The sites for those structures still have 40-foot openings that will form kind of a basement for the reactor buildings.

With Friday's placement of the strut for the first cooling tower, the scene around the 3,150-acre construction site -- one of the largest building projects in the South -- will begin to change.

"Everything's kind of below the surface," Rauckhorst said. "Well, today, the first X brace on the Unit 3 tower is going to get stood up. That will be the first piece that is actually above ground."

The underground work, including the pipes for steam and cooling water, represents roughly 40 percent of the whole project that is slated to last until the reactors begin generating electricity in 2016 and 2017.

"What's going to happen in 2013 is we're going to go vertical," he said. "We're coming out of the ground. ... Now the landscape of this whole project is going to change dramatically in the next 12 months. People will now see, wow, this thing is coming together."

Asked if there would be a "topping out" ceremony like is common when the highest girder is installed on a skyscraper, the executive grinned and said he didn't know. The workers themselves or Shaw, the construction company, may organize one out of their pride.

Other major milestones for the project include later this year when the first reactor vessel arrives on site from Japan. Company officials won't provide details about how and when for security reasons, but they said it has already passed through the Panama Canal. That will be the will be the first center for a reactor core in the United States since the electricity industry stopped building nuclear plants in the wake of the Three Mile Island incident.

Another major milestone will be the 54-hour continuous pouring of concrete for each containment buildings. An on-site concrete plant and a dedicated fleet of trucks will supply the material that must be poured at one time so that it fuses together into one seamless, watertight piece.