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Georgia Power completes Condenser Vacuum Testing on Vogtle Unit 3

December 4, 2020

Georgia Power today announced the completion of the pre-operational condenser vacuum test of the Vogtle Unit 3 turbine system. The milestone marks another step for the Vogtle 3 & 4 nuclear expansion project towards operations and providing customers with a clean, carbon-free energy source for the next 60 to 80 years.

The test was conducted with the main turbine on turning gear and by operating supporting systems to establish the condenser vacuum, which is necessary to demonstrate the steam supply and water-cooling systems operate together and are ready to support hot functional testing and initial fuel load in the reactor.

The condenser is part of the plant's turbine system, separate from the nuclear reactor, that liquifies steam to be reused after its passes through the high- and low-pressure turbines to power a generator and produce electricity. The condenser vacuum test required multiple systems, including circulating water, condensate, auxiliary steam and condenser air removal, to be operated in an integrated manner after having been successfully tested individually.

In preparation for this milestone, the turbine was previously tested and rotated on its turning gear to verify it was assembled with quality and as designed. The main turbine system consists of one high-pressure turbine and three low-pressure turbines.

Once operational, the turbine will rotate at 1,800 revolutions per minute, propelled by steam produced by the unit's two steam generators using heat transferred from the nuclear reactor. The turbine blades turn the generator rotor to produce electricity. 

2020 Milestones Achieved

  • Unit 4 Shield Building Roof Placement - The two-million-pound roof of the Unit 4 shield building has been set into place. With this placement, there is now one last major crane lift remaining for Unit 4, the CB-20 module, which is part of the AP1000 reactor's advanced passive safety system.
  • Unit 3 Nuclear Fuel Receipt –With the receipt of the first nuclear fuel assemblies in December, the site is preparing for the last major test remaining for Unit 3, hot functional testing, ahead of initial fuel load.
  • Completion of Unit 3 Cold Hydro Testing – Confirmed the reactor's coolant system functions as designed and verified the welds, joints, pipes and other components of the coolant system and associated high-pressure systems do not leak when under pressure.
  • Emergency Preparedness Drill – Vogtle 3 & 4 completed a required emergency preparedness exercise for a simulated emergency event for Vogtle Unit 3. Teams participated in the simulation and demonstrated their ability to effectively and efficiently respond and protect the health and safety of the public.
  • Vogtle 3 & 4 Operators Receive Licenses – The Nuclear Regulatory Commission (NRC) issued the first operator licenses to 62 Reactor and Senior Reactor Operators for Vogtle 3 & 4. To receive a nuclear operator license from the NRC, license holders must demonstrate they possess the required knowledge, skills and abilities to safely and effectively operate the plant.
  • Completion of Closed Vessel Testing – The completion of this milestone prepared Unit 3 for cold hydro testing. Closed vessel testing verified the pipes and valves in the Unit 3 reactor coolant system were installed as designed and helped ensure safety systems function properly.
  • Completion of the Structural Integrity Test and Integrated Leak Rate Test – Both tests were completed in succession for Unit 3 and demonstrated the containment vessel meets construction quality and design requirements.
  • Placement of the final module for Unit 3 – The water tank that sits atop the containment vessel and shield building roof, known as module CB-20, is a major part of the AP1000 reactor's advanced safety system and will hold approximately 750,000 gallons of water ready to flow down in the unlikely event of an emergency to help cool the reactor.
  • Placement of the Unit 3 integrated head package (IHP) atop the reactor vessel – Standing 48 feet tall, weighing 475,000 pounds and containing more than three miles of electrical cables, the IHP will eventually be used by highly-trained nuclear operators to monitor and control the nuclear reaction that will occur inside the Unit 3 reactor vessel.
  • Completion of Open Vessel Testing for Unit 3 – This successfully demonstrated how water flows from the key safety systems into the reactor vessel ensuring the paths are not blocked or constricted, and confirmed the pumps, motors, valves, pipes and other components of the systems function as designed.
  • Placement of the polar crane and containment vessel top for Unit 4 – This signified that all major lifts inside the containment vessels for both units are complete.

With more than 7,000 workers on site, and more than 800 permanent jobs available once the units begin operating, Vogtle 3 & 4 is currently the largest jobs-producing construction project in the state of Georgia.

Photos Highlight Progress
Follow the progress being made at the site of the nation's first new nuclear units in more than 30 years through the Plant Vogtle 3 & 4 Online Photo Gallery and Georgia Power's YouTube channel.

About Georgia Power
Georgia Power is the largest electric subsidiary of Southern Company (NYSE: SO), America's premier energy company. Value, Reliability, Customer Service and Stewardship are the cornerstones of the company's promise to 2.6 million customers in all but four of Georgia's 159 counties. Committed to delivering clean, safe, reliable and affordable energy at rates below the national average, Georgia Power maintains a diverse, innovative generation mix that includes nuclear, coal and natural gas, as well as renewables such as solar, hydroelectric and wind. Georgia Power focuses on delivering world-class service to its customers every day and the company is recognized by J.D. Power as an industry leader in customer satisfaction. For more information, visit and connect with the company on Facebook (, Twitter ( and Instagram (

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