Japan's 8th reactor is back online. Kansai Electric Power Company on Wednesday restarted a reactor at the Ohi plant in Fukui Prefecture, central Japan.
At the plant, workers pulled out the control rods that suppress atomic fission of the No.4 reactor.
The facility is expected to reach criticality early Thursday, begin power generation and transmission on Friday and go into commercial operation in early June.
The reactor had complied with new government regulations put in place following the 2011 Fukushima Daiichi nuclear accident.
Two months earlier, the utility reactivated the No.3 reactor at the plant. Two more reactors are running at its Takahama plant about 13 kilometers west of Ohi.
Although they all passed the government's new regulations, attention is now focused on the threat of multiple accidents at these plants in the event of an earthquake and tsunami.
This summer, the government plans to hold its first drill based on a scenario that accidents have occurred simultaneously at the Ohi and Takahama plants.
In 2014, the Fukui District Court ruled against putting the No.3 and No.4 reactors at Ohi back online. It said estimated tremors of possible quakes at the plant are too optimistic. The ruling was appealed to a higher court, which has yet to decide the issue.