The restart of the Kashiwazaki-Kariwa nuclear power plant in Niigata Prefecture on May 9 is likely to revive public concerns about safety but relieve political concerns harbored by the government and the power industry.

Tokyo Electric Power Co. restarted the No. 7 reactor at 2 p.m. by pulling out a control rod to trigger a fission reaction. The reactor reached criticality in 90 minutes, Tepco said.

Concerns about safety have been mounting ever since a series of fires broke out at the world's biggest nuclear power station.

The government is pinning its hopes on the restart because it is eager to reduce greenhouse gas emissions in its stated battle against climate change.