Second new Vogtle nuclear reactor begins splitting atoms

Milestone comes less than two weeks after Georgia Power announced the unit’s completion would be delayed again
A view of the cooling tower for unit 4 at Plant Vogtle, in Burke County near Waynesboro, on Monday, July 31, 2023. (Arvin Temkar /

Credit: Arvin Temkar/AJC

Credit: Arvin Temkar/AJC

A view of the cooling tower for unit 4 at Plant Vogtle, in Burke County near Waynesboro, on Monday, July 31, 2023. (Arvin Temkar /

Georgia Power has begun splitting atoms to produce heat inside the second of its two new nuclear reactors at Plant Vogtle, a key milestone toward completion of the long-delayed project.

The step known as “initial criticality” means a self-sustaining fission reaction has started inside the reactor core of the unit, known as Unit 4. That reaction releases heat to produce steam that turns the unit’s turbines and eventually, will allow it to generate electricity.

Georgia Power said in a statement that operators will continue conducting tests as they raise power levels in the reactor before syncing the generator to the electric grid and beginning to send electrons out to homes and businesses across the state.

The news comes less than two weeks after the company announced a new delay at Unit 4, after vibrating pipes in one of the unit’s critical cooling systems were recently detected during start-up testing. The issue has been fixed, but Unit 4 is not expected to enter service until sometime between April and June. Previously, Georgia Power had said the unit would be finished by the end of March.

The new Vogtle units are the first new commercial reactors built from scratch in the U.S. in more than three decades. Unit 3 has been in service since last July and once Unit 4 is complete, the two reactors combined will produce enough carbon-free electricity to power 1 million homes.

But the project has faced years of delays and rising costs, most of which are being passed on to Georgia Power’s ratepayers.

Unit 3 entered service more than seven years behind schedule, and Unit 4 is likely to reach the finish line more than seven years later than expected, too. The total cost of the expansion has surpassed $35 billion, more than $20 billion more than what was forecast at the project’s outset.

Before Vogtle’s first new unit produced any electricity, the average residential customer had already paid about $1,000 over the last decade-plus in their monthly bills to cover financing costs.

Late last year, state regulators voted to approve a deal that passed $7.56 billion of Vogtle’s construction costs onto the company’s ratepayers. The result for the average residential customer using 1,000 kilowatt-hours of electricity a month is a cumulative increase of $14.38 in their monthly bills. A portion of that increase — about $5.42 — kicked in last year after Unit 3 entered service. The rest will take effect when Unit 4 comes online.

Georgia Power’s parent, Southern Company, is expected to share more information about the timeline for Unit 4′s completion during its earnings call on Thursday.

Georgia Power holds the largest ownership stake in the Vogtle expansion with 45.7%, followed by Oglethorpe Power (30%), the Municipal Electric Authority of Georgia (22.7%) and Dalton Utilities (1.6%).

A note of disclosure

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