Two reactors will go offline for routine checks on Sept. 15, the first time the nation will be without electricity generated by nuclear power in more than a year, government sources said.

It will be the second time that all of the nation's 50 commercial reactors are offline at the same time since the 2011 Fukushima No. 1 plant disaster started, sparking public fears about the safety of nuclear power.

The two reactors currently online are units 3 and 4 at Kansai Electric Power Co.'s Oi plant in Fukui Prefecture. The utility has reported to the Nuclear Regulation Authority that the checks for reactor 3 unit will start Sept. 2, and plans to report that checks for unit 4 unit will commence Sept. 15.