Shikoku Electric Power Co. on Saturday restarted a reactor at its Ikata nuclear power plant after a suspension of nearly one year due to a high court order.

The restart of the No. 3 unit at the plant in the town of Ikata, Ehime Prefecture, announced by the power company overnight Friday, came after a high court accepted an appeal by the utility in a late September ruling that there are no safety risks associated with potential volcanic activity in the region.

The utility said the unit reached criticality, a controlled self-sustaining nuclear fission chain reaction, on Saturday evening as planned.