Japan has started the process of switching off its last working nuclear reactor for a scheduled inspection with no restart date in sight due to public hostility towards atomic power.
The move Sunday leaves the world's third largest economy without atomic energy for the second time since the Fukushima crisis erupted in March 2011.
Prime Minister Shinzo Abe has openly supported the use of nuclear energy, but the public has remained largely opposed to it for fears of possible serious accidents following the world's worst atomic disaster since Chernobyl in 1986.
Kansai Electric Power will gradually take offline the No. 4 reactor at its Oi nuclear plant in Fukui prefecture in western Japan.
The work began Sunday evening, with the reactor expected to stop power generation after several hours before coming to a complete stop Monday, according to the utility.
Japan was previously without any nuclear energy in May 2012, when all of the country's 50 commercial reactors had stopped for scheduled checkups, with utilities unable to restart them due to public opposition.
Last year, government officials and utilities voiced concerns that Japan could experience major blackouts without nuclear power, particularly in the western region that relied heavily on nuclear energy.
Their fears proved to be unfounded--thanks in large part to effective energy conservation programs--but the government gave approval for Kansai Electric to restart No. 3 and No. 4 reactors at the Oi plant, arguing that nuclear energy was necessary to meet increased electricity demand during the winter. (Japanese demand for electricity tends to peak in late summer, with a near-comparable spike in early winter.)
The reactors were restarted in July 2012 and resumed full commercial operation the following month, while other Japanese reactors have remained idled all along.
Japan has turned to pricey fossil-fuel alternatives to fill the gap left by the shutdown of atomic plants, which had supplied about one-third of the resource-poor nation's electricity before the Fukushima disaster.
Utilities have raised power fees to cover increased fuel costs for thermal plants while reactors remain offline.
Radiation spread over homes and farmland in a large area of northern Japan when a massive earthquake and ensuing tsunami disabled cooling systems at Fukushima Daiichi on March 11, 2011.
Last month, Japanese officials announced that the contamination was worse than previously thought.
An estimated 80,000 gallons of contaminated water has been leaking into the Pacific Ocean every day, Yushi Yoneyama, an official with the Minister of Economy, Trade and Industry said on Aug. 7.
Nearly 500,000 people were evacuated from areas around Fukushima in the days following the start of the crisis, and tens of thousands are still not permitted to return. Some areas expected to be uninhabitable for many decades.
Al Jazeera and wire services