The State Ports Authority’s Columbus Street Terminal will serve as a major staging area for a nuclear power plant expansion in the Midlands.

Westinghouse Electric Co. plans to use the downtown maritime property to handle oversize cargo it will be importing as part of the utility project, the SPA said today.

The port will be handling about 24,000 tons of equipment to be delivered to the V.C. Summer plant in Jenkinsville, where South Carolina Electric & Gas Co. and Santee Cooper are adding two reactors at a cost of $10 billion.

Shipments are scheduled to begin arriving at Columbus Street in December and continue for more than four years. An estimated 30 vessels will bring in the machinery and other equipment, with some pieces weighing up to 700 tons.

The cargo will be delivered by rail and truck to the V.C. Summer site, which is about 30 miles northwest of Columbia.

The SPA said the Westinghouse deal underscores its desire to keep the Columbus Street yard as a cargo terminal.

Two downtown Charleston neighborhood associations want the state maritime agency to develop its new cruise ship passenger building at the north end of the property instead of Union Pier.