Georgia Power announced the completion of the pre-operational condenser vacuum test of the unit 3 turbine system and the unit 4 shield building roof placement. 

The unit 4 shield building roof measures 135 feet in diameter, 37 feet tall and weighs 2 million pounds.  The shield building provides an additional layer of safety around the containment vessel and nuclear reactor to protect the structure from any potential impacts, and is a feature of the AP1000 reactor design for the Vogtle units, Georgia Power said.  With this placement, there is now only one last major crane lift remaining for unit 4.

The pre-operational condenser vacuum test at Vogtle unit 3 showed that the steam supply and water-cooling systems can operate together and are ready to support hot functional testing and initial fuel load in the reactor. The 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. Before the test could be performed, the turbine was previously tested and rotated on its turning gear. 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.

Unit 3 is expected to be in service by November 2021 and unit 4 by November 2022.