Georgia Power today announced the completion of cold hydro testing for Vogtle Unit 4 at the nuclear expansion project near Waynesboro, Ga. The completion of cold hydro testing is required to support the last major test remaining for Unit 4, hot functional testing, which is projected to commence by the end of the first quarter of 2023.

“The team at the Vogtle 3 & 4 site continues to make important progress as we move closer to bringing online the first new nuclear units to be built in the country in over 30 years. Completion of cold hydro testing on Unit 4 is another critical milestone along the path to get us there,” said Chris Womack, chairman, president and CEO of Georgia Power. “These units are a long-term investment for our state and essential to building the future of energy for Georgia. For the next 60 to 80 years, they will help us continue to provide clean, safe, reliable and affordable energy for our customers, serving generations of Georgians as clean, emission-free sources of energy.”

Cold hydro testing on Unit 4 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. As part of the testing, the reactor coolant system was filled with water and pressurized above-normal operating conditions, then lowered to normal design pressure while comprehensive inspections were conducted to verify the systems meet design standards.

Other recent milestones for Vogtle Unit 4 include:

- Closed vessel testing (CVT) – Completed in early November, this testing process verified that the pipes and valves in the Unit 4 reactor coolant system are installed as designed and helps ensure safety systems function properly. To carry out CVT on the plant’s passive safety systems, workers installed the reactor vessel head as well as the lower and upper reactor internals and flow restrictors which will be used during hot functional testing to mimic flow through the reactor core.

- Rotation of turbine on turning gear – Also in November, the Unit 4 Turbine was rotated on its turning gear for the first time, demonstrating the turbine was assembled with quality and that integrated oil systems function as designed. The main turbine system consists of one high-pressure turbine and four low-pressure turbines. Rotating the turbines on the turning gear ties in all the oil systems and a significant number of supporting systems in the turbine island, which is a separate structure outside of the unit’s nuclear containment building. 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.

Following the safe loading of nuclear fuel for Vogtle Unit 3 in October, teams at the site have continued to advance through various phases of start-up testing. Vogtle Unit 3 is projected to enter service in the first quarter of 2023.

The new Vogtle units are an essential part of Georgia Power’s commitment to delivering clean, safe, reliable and affordable energy to its 2.7 million customers. Once operating, the two new units, which will be clean energy sources that produce zero air pollution, are expected to power more than 500,000 homes and businesses. Southern Nuclear will operate the new unit on behalf of the co-owners: Georgia Power, Oglethorpe Power, MEAG Power and Dalton Utilities.