Tokyo: The last working reactor in Japan is to be switched off on Saturday, leaving the country without nuclear power just over a year after the world's worst atomic accident in a quarter of a century.

As technicians ready to close down the Number 3 unit at Tomari in Hokkaido, the debate over whether Japan needs nuclear power has been reignited, amid increasingly shrill warnings of summer power blackouts.

Hokkaido Electric Power, which runs the plant, said they would at 5 pm (13:30 IST) begin inserting control rods that would halt the chain reaction and bring the reactor to "cold shutdown" some time on Monday.

The shuttering will mark the first time since the 1970s that resource-poor and energy-hungry Japan has been without nuclear power, a technology that had provided a third of its electricity until meltdowns at Fukushima.

The tsunami-sparked disaster forced tens of thousands of people from their homes in an area around the plant -- some of whom may never be allowed to return. It did not directly claim any lives, but has devastated the local economy, leaving swathes of land unfarmable as radiation spewed from the ruins.

With the four reactors at Fukushima crippled by the natural disaster public suspicion of nuclear power grew, so much so that no reactor shut for routine safety checks has since been allowed to restart.

When the fission reaction stops in the middle of Friday night, Japan's entire stable of 50 reactors will be offline, despite increasingly urgent calls from the power industry and bodies like the OECD, who fear dire consequences for the world's third largest economy.

Last month, Kansai Electric Power, which supplies mid-western Japan, including the commercial hubs of Osaka, Kyoto and Kobe, said a hot summer could see supply fall nearly 20 percent short of demand.

Kyushu Electric Power, covering an area further west, as well as Hokkaido Electric Power also said they will struggle as air conditioning gets cranked up in Japan's sweltering summer.

Kansai Electric last month booked a USD 3 billion annual loss, turning around a USD 1.5 billion profit the year earlier on the increased cost of using previously mothballed thermal fuel plants.

(Agencies)

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