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The government and Tokyo Electric Power Co. said Monday they may be able to start removing the melted fuel inside the crippled nuclear reactors at the Fukushima Daiichi complex within the first half of fiscal 2020 by improving work efficiency, around 18 months earlier than initially planned.
The schedule was included in a draft version of a revised road map toward decommissioning the Nos. 1 to 4 reactors at the plant, but prospects are unclear because technology must be developed to perform the work.
The fuel inside the Nos. 1 to 3 units is believed to have melted through the reactor pressure vessels and been accumulating in the outer primary containers, making the task of defueling more challenging than in the case of the 1979 Three Mile Island accident in the United States.
Apparently taking into consideration the uncertainties ahead, the government and plant operator TEPCO maintained the overall timeline for completing the decommissioning process within 30 to 40 years from the point the plant achieved a stable state of cold shutdown in December 2011.
"How much time we need to take out the fuel debris hinges on the situation of the fuel. Our basic policy is to accelerate such work as much as possible, but we are not moving up the goal of spending 30-40 years," an Economy, Trade and Industry Ministry official said.
The revised road map is expected to be compiled later this month after listening to the opinions of local governments and experts, he added.
According to the draft road map, workers may be able to start removing the melted fuel from the Nos. 1 and 2 reactors within the first half of fiscal 2020 at the earliest by installing new structures for fuel removal and restoring existing fuel handling equipment.
As for the No. 3 reactor, fuel removal could start within the latter half of fiscal 2021.
But the time schedules could be delayed depending on how resistant reactor buildings are to earthquakes, or how much the buildings are contaminated with radioactive substances.
The draft showed that fuel removal could start from fiscal 2022 for the No. 1 reactor, fiscal 2024 for the No. 2 reactor, and fiscal 2023 for the No. 3 reactor at the latest.
According to the official, it will be the first time that the specific timing of fuel removal for respective reactors will be included in the decommissioning road map. The current plan has only said that defueling will start in December 2021 without specifying which reactor will be the first.
Prior to removing the melted fuel, TEPCO plans to start taking out fuel assemblies from spent fuel pools located atop the Nos. 1 to 4 reactor buildings.
The work will start from the No. 4 unit later this year. The No. 4 reactor was offline for maintenance work with fuel stored in the spent fuel pool when the huge earthquake and tsunami ravaged the plant on March 11, 2011.