The process to remove melted fuel from one of the crippled reactors at the Fukushima Daiichi nuclear plant, initially planned to start in 2021, will be delayed by at least a year due to the coronavirus pandemic, the government said Thursday.

The spread of the virus has stalled the development in Britain of a robotic arm to be used for the removal of the fuel from the No. 2 reactor, the Ministry of Economy, Trade and Industry said.

Supplied photo shows the fuel rods of the No. 2 reactor at the Fukushima Daiichi nuclear power plant. (Photo courtesy of Tokyo Electric Power Company Holdings Inc.)(Kyodo)

Removal of the fuel debris is seen as the most difficult part of a decades-long process to decommission the Fukushima nuclear complex, which suffered core meltdowns following the March 2011 earthquake and tsunami in northeastern Japan.

"We will put safety first and make efforts to ensure that the delay of the process will be limited to around a year," a ministry official told reporters.

The official said the robotic arm will be transported to Japan around April next year for further development. Radioactivity levels inside the reactors are still too high to manually remove the melted fuel.

The Nos. 1 to 3 reactors at the complex are estimated to house around 880 tons of debris. Plant operator Tokyo Electric Power Company Holdings Inc. selected the No. 2 reactor for the start of fuel removal as it believes it has the best grasp of that unit's internal conditions.

The government and TEPCO have said they expect the plant's decommissioning to be completed between 2041 and 2051.

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