Georgia Power today announced that Vogtle Unit 3 has safely reached initial criticality. Initial criticality is a key step during the startup testing sequence and demonstrates that -- for the first time -- operators have safely started the nuclear reaction inside the reactor. This means atoms are being split and nuclear heat is being made, which will be used to produce steam.A reactor achieves criticality when the nuclear fission reaction becomes self-sustaining. Achieving initial criticality is necessary to continue the startup of the Unit in order to generate sufficient heat for the production of electricity.

"We remain focused on safely bringing this unit online, fully addressing any issues and getting it right at every level. Reaching initial criticality is one of the final steps in the startup process and has required tremendous diligence and attention to detail from our teams," said Chris Womack, chairman, president and CEO of Georgia Power. "When you consider the history of safe and reliable operations at Vogtle Units 1 and 2 for decades now, it puts today's milestone in perspective that Plant Vogtle will be a four-unit site making it the largest of its kind in the U.S. This is a truly exciting time as we prepare to bring online a new nuclear unit that will serve our state with clean and emission-free energy for the next 60 to 80 years." 

Vogtle Unit 3 continues with startup testing which demonstrates the integrated operation of the primary coolant system and steam supply system at design temperature and pressure with fuel inside the reactor. Now that the Unit 3 reactor has reached criticality, operators will continue to raise power to support synchronizing the generator to the electric grid and begin producing electricity. Then, operators will continue increasing power through multiple steps, ultimately raising power to 100 percent. These tests are designed to ensure all systems are operating together and to validate operating procedures prior to declaration of Commercial Operation. The in-service date for Unit 3 is projected during May or June 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 units on behalf of the co-owners: Georgia Power, Oglethorpe Power, MEAG Power and Dalton Utilities.