Workers at Grand Gulf Nuclear Station today were repairing a damaged vacuum seal that has kept the reactor shut down since Saturday.

Entergy Nuclear spokesman Tim Crisler said a fracture caused a condenser failure.

&#8220A seal is being replaced. It’s not a complex problem, and the situation is under control,” Crisler said.

Plant managers do not set specific timetables for restarting operations after repairs or other shutdowns at boiling water reactors, Crisler said, and instead resume production as demand indicates.

Although the nuclear plant is a key component in providing electricity in Mississippi, Louisiana and Arkansas, the Entergy system has generating capacity to serve customers without it.

Completed in 1985 for $3 billion, the plant sits on 2,100 acres on U.S. 61, just north of Port Gibson, and provides about 25 percent of the state’s electricity output.

Of its work force of more than 700, about 370 full-timers live in Port Gibson and Vicksburg.

Earlier this month, the plant received praise from both industry trackers and federal regulators for safety and incident preparedness.

Grand Gulf was given high marks for output by energy and metals information provider Platts, ranking third out of 100 power-generating nuclear plants nationwide. The plant also earned the highest safety rating possible from the Nuclear Regulatory Commission in annual safety assessments.

Efforts to build a second reactor at the site are still in progress. A consortium of power companies, NuStart, received an early site permit from the NRC in April after the plant was deemed suitable for additional construction after environmental and safety studies.

A decision is expected during the next five years on whether a second reactor will be built, at a cost of about $4 billion.

If expected timelines stay true, however, it would be the first new nuclear reactor construction in the United States since the 1970s. The most time a reactor was licensed by the NRC was in 1996.