Today—Meeting Key Targets
The Watts Bar Unit 2 team continues to meet key targets for safety, quality, cost and schedule.
The project has recently completed four significant milestones:
- Pressure tested the primary side of steam generator and the reactor coolant system.
- Assembled the nuclear reactor vessel
- Conducted Open Vessel Testing, which verifies that safety-related systems inject water into the reactor vessel as designed
- Constructed of one of the first functional FLEX equipment storage buildings in the industry
Once operational, Watts Bar Unit 2 will produce the nation’s first new nuclear generation of the 21st century—low-cost, clean, carbon-free power.
October 2014—NRC Official Visits
U.S. Nuclear Regulatory Commission member Kristine Svinicki toured Watts Bar on Oct. 22. While at the site, she was briefed on the work to complete Watts Bar Unit 2, transitioning Watts Bar to dual-unit operation, and integrating the dual-unit site into TVA’s nuclear fleet.
Commissioner Svinicki’s visit is the fourth tour of Watts Bar Unit 2 by an NRC commissioner this year. The visits provide a first hand look at the completion project and how TVA is ensuring Unit 2 is being built safely, with quality and in a manner designed to ensure excellence in operation following licensing.
October 2014—Cold Hydrostatic Testing
Watts Bar Unit 2 passes a major pressure test: Primary Cold Hydrostatic Testing, or Cold Hydro. By demonstrating that the systems and components that are central to nuclear operations can safely hold pressure above the normal operating value of 2250 psi, the team completed a major testing milestone. That’s puts Watts Bar Unit 2 one step closer to becoming the nation’s first new nuclear power generation of the 21st century.
September 2014—Safety Milestone
Safety is top priority at Watts Bar Unit 2. The team has logged more than 28.8 million hours without a lost-time incident.
August 2014—Reactor Vessel Is Assembled
The Watts Bar Unit 2 team safely completed the first and largest portion of assembling the reactor vessel: placing the core barrel into the reactor vessel. Inspections were performed at every stage as the 282,000-pound barrel was lifted and then lowered into the reactor. The entire lift process took approximately 12 hours to safely set up and complete—and was executed perfectly.
This was the first of three lifts that need to be completed to assemble the Unit 2 reactor for Cold Hydro, a pressure test that requires the reactor vessel to be assembled and tests the reactor coolant system and the high-pressure portions of the residual removal system, the steam generator and the chemical and volume control system and the safety injection system.
July 2014—FLEX Buildings Mean Safety
Watts Unit Bar 2 is the the first nuclear plant in the U.S. to meet new Nuclear Regulatory Commission regulations established after the 2011 earthquake and tsunami that struck Fukushima Nuclear Plant in Japan. Watch the construction of one of the first functional FLEX buildings in the industry, complete with a 16-foot-tall tornado-proof door, designed to protect emergency equipment from missiles created in tornado situations, including flying cars.
July 2014—Open Vessel Testing
On July 1, 2014, Watts Bar Unit 2 completed Open Vessel Testing, which tests key safety and safety-support systems designed to deliver water to the reactor vessel. The time-lapse video below shows approximately 185,000 gallons of water flowing into the Watts Bar Unit 2 reactor vessel over a 23-minute period of testing.
Watts Bar team members now are reassembling the reactor in preparation for a second major testing milestone, Cold Hydro. This test verifies that welds, joints, pipes, components of the reactor coolant system and associated high-pressure systems meet quality standards.
June 2014—Cooling Tower Turned Over to Operations
Watts Bar Unit 2’s massive cooling tower was transferred from Nuclear Construction to Nuclear Operations, signaling its readiness for operations.
When a plant is operating, cooling water from the condenser is distributed through pipes and baffles inside the cooling tower and falls like rain about 60 feet, which cools the water before it is continuously recycled to condense more steam. Water in the vapor rising from the cooling tower is replenished to the condenser cooling system with water from the Tennessee River.
May 2014—Coolant System Ready for Testing
Watts Bar Unit 2 completed a significant amount of work to release the reactor coolant system to the site’s pre-operational startup engineering team after completing more than 192,000 craft hours and more than 1,200 work orders.
The system is the heart of the nuclear plant, constantly circulating highly pressurized water through the reactor, four steam generators, a pressurizer and the piping that connects them to the reactor. Inside the steam generators, the heat from the water coming from the reactor is transferred to a second separate supply of water that turns to steam that powers the turbine generator. See how Watts Bar Nuclear Plant uses steam to make power.
April 2014—Prepping for Testing
Engineers get an early jump on preparations for Open Vessel Testing, the first in a series of major milestones to lead Watts Bar Unit 2 to regulatory approval to load fuel. Open Vessel Testing ensures key safety systems and safety support systems work as designed to deliver water to the reactor vessel. Open Vessel Testing will culminate in water flowing into the reactor at about 10,000 gallons a minute.
April 2014—Operators Presented with Licenses
Eight nuclear professionals were formally presented with their Watts Bar Unit 2 operator licenses by Nuclear Regulatory Commission officials at an awards dinner in Cleveland, Tenn. The ceremony marked the licensed operators’ completion of 18 months of training and testing requirements.
January 2014—Shifting Gears
The focus of work on the Watts Bar Unit 2 is shifting from large-scale construction to completion and testing of individual plant systems.
October 2013—Meeting Challenges
Safety and quality continue to be excellent as workers move toward delivering Watts Bar Unit 2 on time and within budget.
However, some challenges are arising, too. These include:
- Completing complex work and required documentation
- Performing testing on shared Unit 1 and Unit 2 systems without impacting the safe and reliable operation of Unit 1
- Addressing regulatory and licensing issues
- Successfully transitioning the site to dual-unit operations
July 2013—Review Yields Good News
The latest quarterly review of the Watts Bar 2 Estimate to Complete found:
- Workers continued to deliver good safety performance.
- Quality performance remained high, improving to 97 percent.
- Overall, cost performance continued to be better than projected in the revised estimate to complete.
- Schedule performance met expectations.
- Challenges are anticipated as the as some systems move into testing mode, and others are completed.
- No new risks emerged that currently compromise completion of the project; regulatory and licensing issues remain the primary concerns.
April 2013—Goals Exceeded
One year after the TVA Board approved the further construction of Watts Bar Unit 2, a quarterly review showed that the project continued to meet or exceed goals for quality, schedule and safety. 18 million work hours had been logged without a lost-time incident, and the overall quality acceptance rate was at 96 percent or better. However, despite the excellence, there will be challenges as the team works to deliver a safe, reliable unit.
February 2013—Moving the Vessel Head
Lifting an assembly made of 144 tons of carbon steel and precisely crafted control rods from a reactor vessel and moving it into a specially built holding stand and then putting it back again is a complex job. But the team achieved the right results and moved the 288,000-plus pound Watts Bar Unit 2 reactor pressure vessel head from its holding stand to the top of the reactor pressure vessel safely.
December 2012—Construction Moves Forward
The Watts Bar Unit 2 project focused on efficiently performing construction activities; maintaining the overall pace of installing commodities, such as valves, piping and cable; and continuing to implement improvement initiatives.
September 2012—Safety First
Building a nuclear plant is a complex task with lots of inherent safety hazards. But workers at Watts Bar Unit 2 recognize this, and by keeping safety first, surpassed 16 million work hours without an accident.
Watts Bar Unit 2 construction workers are demonstrating their commitment to keeping themselves and others safe by:
- Wearing the right personal protective equipment for every job
- Taking 2 minutes before they start work to identify potential hazards
- Immediately reporting potential safety issues and every injury so appropriate steps can be taken to prevent future injuries
- Intervening to protect each other from unsafe acts and to reinforce safe behaviors
April 2012—Green Light for Watts Bar Unit 2
The TVA Board of Directors approved continuing the construction of Watts Bar Unit 2 with a revised estimate to complete of $4 billion to $4.5 billion. Estimates have it that the unit will be completed between September 2015 and June 2016. Once operational, Watts Bar Unit 2 will produce the first new nuclear generation in the United States—providing energy that is low-cost and carbon-free. When completed, Watts Bar Unit 2 will generate 1,150 megawatts of electricity—enough for about 650,000 homes in the Tennessee Valley.