The Nuclear Regulatory Commission says a nuclear power plant 25 miles west of New Orleans has declared an “unusual event″ — its lowest level of emergency — after the facility lost offsite electrical power.

The Waterford nuclear plant in Killona, La., had shut down protectively on Saturday in anticipation of Hurricane Ida. The plant has maintained safe shutdown conditions with power from emergency diesel generators, the nuclear agency said.

On Sunday night, grid operators requested that the River Bend nuclear power plant in St. Francisville, Louisiana, reduce power because of load demands. The plant is stable and operating at 35 percent power with no significant equipment issues reported, officials said.

The Grand Gulf nuclear plant in Port Gibson, Mississippi, is operating at full power with no significant weather-related issues expected from Ida. No significant flooding has been reported at any of the sites.

Ida weakened to a tropical storm as it moved to Mississippi.