Construction of unit 2 at the Watts Bar nuclear power plant will continue after the board of Tennessee Valley Authority (TVA) accepted a revised cost estimate. The expected completion date of the project has now slipped to 2015.

he construction of Watts Bar 2 started in 1973, but was stopped in 1985 when it was about 55% completed. TVA decided in 2007 to resume the job, expecting it to cost $2.5 billion and to be completed under Bechtel’s management by 2012. However, by August 2011 TVA had taken back control of the work and set a new completion target of 2013. By February 2012, some 81% of the overall project had been done, with instrumentation and electrical work slightly ahead of schedule and mechanical work slightly behind.

A revised estimate for the project was announced earlier this month following a seven-month, top-to-bottom analysis and a change of management at the construction site. This included additional funding of $1.5 billion to $2.0 billion, bringing the total cost to complete the reactor between $4.0 billion and $4.5 billion with a likely estimate of $4.2 billion. In addition, the schedule has now been pushed back to late 2015.

The TVA board has now approved continuing with construction of Watts Bar 2 in accordance with this revised cost estimate and schedule.

TVA president and CEO Tom Kilgore told the board, “TVA expects Watts Bar 2 to be among the best operating and most economical nuclear generating facilities of the 21st century.” He added, “The safe and continuing completion of Watts Bar 2 will help us deliver a balanced mix of energy sources and increase our supply of emission-free electricity”.

In addition, the board approved a ten-year, $298 million contract for the construction of a dry cask storage facility for used fuel at Watts Bar, as well as additional dry storage capacity at its Sequoyah and Browns Ferry nuclear power plants.

TVA is also planning to complete the partially-built Bellefonte 1 reactor in Alabama although it has said construction at Bellefonte would not begin unit Watts Bar 2 reaches the fuel loading stage. The change in schedule for completing Watts Bar 2 will therefore put back the start of work on Bellefonte 1. Last month TVA announced that it was reducing the number of contractors working on the Bellefonte project as it resets its priorities.