Crews are doing maintenance work, including periodic refueling, at a nuclear power plant in southwestern Mississippi.

Entergy spokesman Mike Bowling said Monday that refueling at Grand Gulf Nuclear Station near Port Gibson takes place every 18 to 24 months — usually during the spring or fall, when peak demand is lower.

Entergy said in a news release that control room operators removed Grand Gulf from the power grid at 9 p.m. Saturday, putting it in safe shutdown. The refueling process usually takes several weeks.

Customers continue to receive electricity in their homes and businesses even as Grand Gulf is offline, with power coming from other sources on the transmission grid, Bowling said.

Entergy holds 90% ownership in Grand Gulf Nuclear Station and Cooperative Energy holds 10%.

Grand Gulf has more than 800 employees. Entergy said hundreds of contract workers are also at the plant during refueling and maintenance, as are Entergy employees from other nuclear plants and headquarters.

The Entergy news release said that after a plant is shut down for refueling, nuclear professionals remove part of the fuel from the reactor, shuffle current fuel rods and replace the removed fuel with new fuel. Also while the plant is offline, the team completes maintenance work and other projects to improve reliability, the release said.