The cooling tower of the single operating reactor at the Watts Bar Nuclear Plant belches steam in Spring City, Tenn.

Despite many starts and stops, TVA's work on a second reactor at Watts Bar Nuclear Plant near Spring City, Tenn., is now 80 percent complete and progressing to the point that much engineering work is in the details of transferring completed systems from construction workers to operators.

The new reactor - once scheduled to go online in 2012 before delays - now is meeting its revised schedule for completion by December 2015 with a projected total cost of $4 billion to $4.5 billion, according to Mike Skaggs, TVA senior vice president for nuclear construction.

"We have not identified any new short-term issues that compromise project completion, but we recognize there are challenges to completing this unit, with regulatory and licensing issues being our primary challenges," Skaggs said.

Skaggs made the report this morning. He makes progress reports quarterly, in accordance with a request from board members after workers had to report to the board that problems had delayed Unit 2's completion by three years and estimated completion costs had nearly doubled.

Skaggs said most of the parts remaining to be installed include cables, small valves, instruments and associated pipes and tubing that make up the operating systems for the reactor.

The transfers of the completed reactor systems require reams of paper documentation and testing, he said, and on several systems the work is being accelerated "to find and prevent potential problems early in the completion and testing" so they won't impede progress later.

Read more in Friday's Chattanooga Times Free Press.