Japan will be without nuclear power for the second time since the Fukushima crisis in 2011.
The nation's last working nuclear reactor in western Japan will be shut down for a scheduled inspection with no restart likely because of public hostility to atomic power.
The public has remained largely opposed to atomic power since a massive tsunami swamped cooling systems at Fukushima nuclear plant.
AFP reports Japan has turned to fossil-fuel alternatives to fill the gap left by the shutdown of its atomic plants, which had supplied about one-third of the nation's electricity before the Fukushima disaster.
Kansai Electric Power will gradually take offline the No. 4 reactor at its Oi nuclear plant in Fukui prefecture in western Japan.
The work is scheduled to start on Sunday evening, with the reactor expected to stop power generation after several hours before coming to a complete stop early on Monday, according to the utility.