French power group Alstom said today it has been awarded a contract by Exelon Corporation (NYSE: EXC), to supply and install steam turbine retrofit equipment at three of Exelon’s nuclear power plants in the U.S.

The increased power output per unit is expected to be 80 MW per facility, said Alstom.

The three facilities, Quad Cities, Dresden and Peach Bottom are to receive the retrofitted steam turbine equipment from Alstom for an estimated $420 million.

Exelon runs approximately 20 percent of the U.S. nuclear industry’s power capacity.

Alstom, based in Levallois-Perret, France, said it has already begun work to replace three low pressure steam turbine sections at the Quad Cities facility in Cordova, Illinois.

According to Alstom, the newer technology in the turbines are expected to result in increased efficiency, greater reliability and increased capacity for the remaining life of the plants.

The Quad Cities nuclear facility is a 765-acre site along the Mississippi River with two Units, which began commercial operation in 1972 and 1973.

Exelon said Unit 1 is currently capable of producing 866 MW, and Unit 2 is capable of 871 MW, which combined, has the potential to power more than 1 million average homes.

Chicago-based Exelon, one of the largest electric utilities in the U.S., operates the largest nuclear fleet in the nation and the third largest in the world with ten stations (seventeen reactors).

Alstom, the top global supplier of nuclear turbine systems, said the equipment for the first project is being manufactured in Belfort, France and Morelia, Mexico, with components for subsequent projects expected to be manufactured in a new $200 million facility in Chattanooga, TN.

Earlier this year Alstom signed agreements TransAlta (NYSE: TAC) signed and Drax Group (LON: DRX) to build a carbon capture and storage plant a biomass plant, respectively (see TransAlta, Alstom to develop CCS project in Alberta and Drax hires Alstom to build biomass plant).