Grand Gulf Nuclear Station was returned to 100 percent operating capacity this morning as repairs to part of the facility wrapped up Wednesday.

A fire in part of the main turbine Tuesday  morning reduced capacity. Officials said an oil-saturated piece of insulation ignited in feedwater pump B turbine. The insulation has since been replaced, officials have said.

The fire broke out at 9:25 a.m. and was brought under control by the facility’s on-site fire brigade by 11:34 a.m. No injuries were reported.

A refueling recently had been completed, officials said, but the source of the oil could not be pinpointed. The plant is refueled once about every 18 to 24 months, spokesman Jami Cameron said this morning.

Grand Gulf, a boiling water reactor, was completed in 1985. Regulatory processes to build a second reactor are under way, with preliminary environmental reviews expected by May. Final drafts of environmental studies are expected by May 2010.

The plant site is on the Mississippi River about 24 miles southwest of Vicksburg. It is the only nuclear plant in Mississippi.