The latest shutdown at Plant Vogtle occurred while its Unit 1 reactor was being put back online after an equipment issue caused it to go down Monday.

Southern Company told the Nuclear Regulatory Commission that heavy vibrations on a turbine caused the most recent outage. The affected turbine helps generate enough electricity to power more than 300,000 homes.

Company officials say they don’t know what caused the vibrations and that an investigation is underway. Carrie Phillips is a spokesperson for Southern Company.

She said, "The vibration issue is not uncommon though we certainly take it seriously. But there’s no impact to the safety of that plant or the safety of anyone and we’re looking at the issue and we’ll get the unit back."

Officials wouldn’t say when they expected the reactor to be back online. Meanwhile, Vogtle’s Unit 2 reactor is fully operational.

Tags: Southern Company, nuclear reactors, U.S. Nuclear Regulatory Commission, Nuclear Regulatory Commission, Plant Vogtle, commercial nuclear reactors, nuclear reactor shutdown