Georgia Power wants the firms building a new nuclear plant in eastern Georgia to pay back more than $29 million in disputed construction costs.

The Southern Co. subsidiary filed a lawsuit Thursday on behalf of itself and the other owners of two nuclear reactors being built at Plant Vogtle (VOH’-gohl) near Augusta.

The dispute centers on excavation work to dig the foundation of the power plant. The utility said in the lawsuit that workers needed to dig the foundation 90 feet deeper than initially anticipated, prompting a dispute over who was responsible for paying for the extra costs.

The builders of the plant previously sued the owners seeking to recover another $29 million for the work. Georgia Power and the owners say they should get a $29 million refund.