Commercial operation of the troubled reactor 4 at the Takahama facility in Fukui Prefecture will likely be pushed back to April after the Nuclear Regulation Authority said it will be difficult to proceed until preventive steps are approved.

Kansai Electric Power Co. had initially planned to start commercial operation of the reactor in late March.

The change in schedule became necessary after the reactor shut down automatically Monday, only three days after coming back online under safety regulations strengthened following the 2011 Fukushima meltdowns.