Company and nuclear regulatory officials said safety systems were operating properly and the public is not at risk.
The reactor, located on the Chattahoochee River near Dothan in southeast Alabama, was shut down for refueling and maintenance.
According to a report from the Nuclear Regulatory Commission, employees tried to restart the unit Sunday morning, but a circuit breaker tripped and stopped the process. A similar problem occurred during a restart attempt early Monday.
Southern Nuclear spokeswoman Regina Waller said workers are trying to figure out what was causing the problem. Regulators said the reactor was stable.
Tuesday night, the NRC will hold a public hearing in Dothan to discuss their annual review of safety performance at the Farley plant. It will begin at 7 p.m. in the Houston County Commission chambers on North Oates Street.