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Watts Bar Unit 2 project construction update

January 16, 2014

Watts Bar Nuclear Plant Unit 2's completion targets continue to be met in safety, quality, cost, and schedule where the focus has shifted from large-scale "bulk" construction to work required to complete and test individual plant systems.

This information and other details about performance at the project are included in the Sixth Quarterly Update to the Watts Bar 2 Estimate to Complete and in the video below.

During the sixth quarter, which covers August to October 2013, more than 3,300 highly skilled workers achieved more than 22.8 million work-hours without a lost-time incident, and the Quality Control Acceptance Rate remained high, with over 97 percent of work presented for inspection meeting quality control requirements.

Looking forward, Watts Bar Unit 2 is steadily approaching a major milestone — open vessel testing — this spring. This test involves pumping water through systems used when shutting down the reactor.

This ongoing progress means Watts Bar 2 remains on target for a most likely completion date of December 2015, within the estimated completion range of between September 2015 and June 2016.

image of workers at Watts Bar Unit Two

During the quarter, no new risks were identified that might compromise project completion. Several challenges still exist given the size, scope and complexity of completing a nuclear reactor. Those include:

  • Completing complex work and required documentation
  • Completing and testing shared systems without impacting Unit 1's safe and reliable operation
  • Addressing regulatory and licensing issues
  • Successfully transitioning the site into dual-unit operation

Watts Bar Unit 2 will play a vital role in TVA meeting the energy needs of Tennessee Valley families and industry with low-cost, reliable and carbon-free electricity. The Watts Bar team recognizes the importance of its work and is committed to completing the project in a safe manner, on time and within budget.

View previous Watts Bar 2 updates

TVA's confidence in the new completion schedule

TVA has high confidence in the new completion schedule and cost estimates for Unit 2.

The estimate to complete – called the ETC – was prepared in collaboration with TVA’s construction contractors and outside experts. The ETC includes a root-cause analysis of the factors that took the project off track and detailed estimates of the costs and time needed to complete the remaining work.

TVA has taken corrective actions to address the issues identified in the root cause analysis and move the project forward.

The ETC also includes detailed estimates for:

  • the amount of conduit, cable, piping and other materials still to be installed;
  • support activities, like scaffolding, insulation and painting; and
  • labor rates.

To validate these estimates, visual inspections were conducted to assess the work already completed, verify the scope of work remaining and confirm the quantity of materials needed.

To provide the highest degree of confidence in the cost and schedule forecasts, two independent assessments were made to confirm the ETC. One assessment reviewed the methodology to prepare the ETC, and the other validated the root cause analysis.

Why TVA needs more nuclear power

TVA’s vision is to be one of the nation’s leading providers of low-cost and cleaner energy by 2020. Even with increases in energy efficiency and demand response programs, TVA will need more generating capacity to achieve its vision and support economic growth and job creation in the Tennessee Valley region.

TVA’s Integrated Resource Plan calls for future generation from a balanced mix of reliable, cleaner and competitively priced sources that include more nuclear power.

TVA already is a leader in the production of safe carbon-free nuclear energy. Nuclear power provides about one-third of the electricity generated by TVA and about 70 percent of TVA’s clean generation.

Nuclear is the best technology for keeping reliability high and rates competitive. It is cleaner than coal and produces no harmful greenhouse gases. And while expensive and complicated to build, nuclear units are economical to operate.

Industry-wide, nuclear is second only to hydroelectric in low production, fuel, and operations and maintenance costs. TVA’s nuclear fuel expenses were about a half cent per kilowatt-hour in fiscal year 2011, compared with 3 cents for coal and 4 cents for natural gas and fuel oil. In 2010, TVA’s combined fuel, operations and maintenance costs for nuclear generation were less than 2 cents per kilowatt-hour.

By increasing nuclear generation, pursuing renewable energy sources and promoting energy efficiency, TVA will rely less on coal, continue steady progress in reducing air emissions, and provide reliable, economical power for the people of our region.

How Watts Bar 2 will help

TVA’s Integrated Resource Plan identified Watts Bar 2 as an essential new source of nuclear generation. Completing Unit 2 will put an existing asset to work for TVA customers and add more than 1,100 megawatts of safe, clean, reliable and economical base load generating capacity to the TVA power system.

Not only will Unit 2 help meet growing demand for electricity in the Tennessee Valley, it will help replace older, more costly and less efficient coal units that are being retired. One nuclear unit can make as much electricity as five to 10 coal units without carbon emissions. It is estimated that Watts Bar Unit 2 will help TVA avoid coal-fired emissions of 6 million to 8 million tons of carbon dioxide a year.

Bringing Watts Bar Unit 2 online will directly support TVA’s vision to be one of the nation’s leading providers of low-cost and cleaner energy by 2020 and, specifically, to:

  • lead the Southeast in increased energy efficiency, and
  • lead the nation in improving air quality and increased nuclear production.

Economic impact of Unit 2 construction

The Unit 2 construction project employs around 2,400 contractors as of April 2012. About 290 permanent positions have been added to support two-unit operation of the plant.

TVA provides financial compensation to cities and counties affected by construction of new generation. In 2012, five counties and 18 cities affected by the construction of Watts Bar Unit 2 will receive more than $2.9 million in compensation from TVA.

Vital statistics about Watts Unit 2

Plant site

  • Location:  Near Spring City in southeastern Tennessee
  • Acreage:  1,700-acre site on Chickamauga Reservoir

Cooling towers

  • Quantity: 2
  • Height:  506 feet
  • Diameter:  405 feet at ground level
  • Water flow:  410,000 gallons per minute


  • 500,000-volt transmission lines: 5
  • 161,000-volt transmission lines: 2

Plant design

  • Westinghouse pressurized water reactor that is expected to generate 1,150 megawatts (summer net capability) – enough to supply power for about 650,000 Tennessee Valley homes
  • Reactor core holds 193 fuel assemblies, each contains 264 fuel rods

Reactor vessel

  • Height:  43.8 feet
  • Weight:  About 265 tons (empty)
  • Inside diameter:  14 feet
  • Steel thickness:  About 9.4 inches
  • Operating temperature:  About 586 degrees Fahrenheit
  • Operating pressure:  About 2,235 pounds per square inch

Primary containment

  • Inside height:  197.3 feet
  • Inside diameter:  115 feet
  • Steel inner thickness:  1 inch
  • Design pressure:  15 pounds per square inch

Steam generators

  • Quantity: 4
  • Height:  67 feet 8 inches
  • Weight:  About 380 tons
  • Operating temperature:  About 600 degrees Fahrenheit
  • Operating pressure:  1,000 pounds per square inch

Main generator

  • Height:  16 feet
  • Length:  40 feet
  • Stator weight:  About 1,000 tons
  • Rotor weight:  About 200 tons
  • Ratings:  1,411 megawatts, 24,000 volts
  • Speed:  1,800 rotations per minute

Steam turbines

  • High pressure:  A single 8-stage double-flow axial turbine
  • Low pressure:  A series of three, 8-stage double-flow axial turbines
  • Maximum blade diameter:  16 feet
  • Rotor weight:  About 177 tons

Main condenser

  • Tubes:  About 27,410
  • Tube length:  About 115 feet
  • Tube diameter:  1 inch



Quarterly Updates (PDF)

Sixth Quarterly Update

Fifth Quarterly Update

Fourth Quarterly Update


White papers

Nuclear program

Watts Bar Unit 2



See videos on TVA's Nuclear program


Watts Bar Unit 2 Timeline

1973 Construction begins.

1985 Unit 2 construction suspended.

1995 Integrated Resource Plan reserves Unit 2 as an option for meeting future power demand.

1996 Unit 1 begins commercial operation.

2000 NRC extends Unit 2 construction permit to December 2010.

2006 TVA begins detailed study of possible completion of Unit 2.

2007 TVA board approves 5-year schedule to complete Unit 2.

2008 Construction begins, NRC extends construction permit to March 2013.

2009 TVA submits updated application for Unit 2 operating license.

2010 Completion schedule evaluated and updated.

2011 TVA's Integrated Resource Plan recommends a balanced portfolio with increased nuclear generation.

2011 Construction workforce reduced to manage cost and efficiency.

2012 TVA Board approves continued completion of Watts Bar 2 in accordance with a revised estimate.


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