South Korea shut down one of its nuclear reactors Friday after a crack was detected in a steam generator tube.

The nuclear reactor at the Yeonggwang plant on the country's southwestern coast was shut down around 6 a.m.

The state-run Korea Hybrid and Nuclear Power said it will investigate the cause of the crack.

Friday's incident is not the first time nuclear reactors at the Yeonggwang plant have experienced problems with its steam generator tubes.