New Georgia nuclear reactor begins splitting atoms in key step to operation start

Southern Co. (NYSE:SO) said Wednesday that Unit 4 at the Vogtle nuclear expansion project has reached initial criticality, a key step during the startup testing sequence showing for the first time that operators have safely started the nuclear reaction inside the second reactor.

A reactor achieves criticality when the nuclear fission reaction becomes self-sustaining, which is necessary to continue the startup of the unit in order to generate sufficient heat for the production of electricity.

Georgia Power said operators will continue conducting tests as they raise power levels in the reactor to support synchronizing the generator to the electric grid and ultimately raise power to 100%.

Plant Vogtle’s Unit 4 is expected to start commercial operation during Q2 2024, after the utility earlier this month announced a delay past an earlier deadline of March 30 because of vibrations found in a cooling system.

Vogtle Unit 3 began commercial operations last summer, joining two older reactors that have been onsite for decades.