After 36 Years, Nuclear Plant in Tennessee Nears Completion

SPRING CITY, Tenn. — Tom Wallace started working at the Watts Bar nuclear plant as a young man in 1979, hoping he could eventually become a reactor operator.

Mr. Wallace, 55, is still awaiting the plant’s opening 36 years later, one of the longest building projects in the country’s history.

In the time it has taken to build it, Mr. Wallace raised two daughters and became a grandfather. Meanwhile, the nuclear industry designed a generation of entirely new plants that are now rising in Georgia and South Carolina.

If nothing else, the second reactor at the Tennessee River site has become a cautionary tale for the power industry. When it is finished, it will provide enough electricity to power about 650,000 homes in the Tennessee Valley. The cost of running a nuclear plant is relatively steady, and doing so does not produce greenhouse gases and other air pollutants. But the facilities are enormously expensive and complicated to build.

The Tennessee Valley Authority vastly overestimated the demand for electricity decades ago. In 1966, it announced plans to build 17 nuclear reactors in Tennessee, Alabama and Mississippi. By 1985, the agency canceled plans for almost half of them because of a slumping economy and spiraling construction costs.

The building of the first reactor, Watts Bar 1, proved a big mess. Regulators approved construction in 1973. A dozen years later, Tennessee Valley Authority officials requested permission to load the plant’s radioactive fuel.

The Tennessee Valley Authority deferred work on its second reactor, which sat unused and was cannibalized for parts. A contractor, Bechtel Power Corporation, estimated in 2007 that finishing it would cost $2.5 billion over five years. The estimate badly missed the mark. The latest projections show the costs will be around $4.3 billion — more expensive than a natural gas plant, but cheaper than building a nuclear plant from scratch.

However, reviving the old technology posed unique issues, and the Tennessee Valley Authority pulled out many old pieces of equipment for replacement or refurbishment.

The utility says its electrical demand is relatively flat, so starting the nuclear plant will allow it to shutter dirtier coal-fired plants. Watts Bar is also a long-term hedge in case natural gas prices rise, the utility’s president, Bill Johnson, said.

Federal safety regulators will decide in the coming weeks whether to grant it an operating license. Mr. Johnson said the plant expected to load its nuclear fuel toward summer’s end and gradually start operations.

A version of this article appears in print on , Section A, Page 13 of the New York edition with the headline: After Decades, Nuclear Plant Nears Completion. Order Reprints | Today’s Paper | Subscribe