Photo/Illutration Water storage tanks fill the premises of TEPCO’s Fukushima No. 1 nuclear power plant on Jan. 19. (Shigetaka Kodama)

Crucial work to remove melted fuel debris from the crippled Fukushima nuclear power plant has been postponed for the third time, again due to a robotic arm that needs more work. 

The government and the plant operator, Tokyo Electric Power Co., said on Jan. 25 that they called off the plan to start a test removal from the plant’s No. 2 reactor by the end of fiscal 2023 in March, citing insufficient precision of a robotic arm to remove the debris.

They now aim to begin the work with an alternate device by October.

A test to remove a few grams of debris from the No. 2 reactor was initially scheduled for 2021, but it was pushed back twice due to delays in the development of the remote-controlled arm.

TEPCO said the arm’s movement still lacks sufficient precision. The utility aims to begin the work using a “fishing rod-style device” by October.

After that, it said it will also attempt removal using the robotic arm.

Companies including Mitsubishi Heavy Industries Ltd. have been involved in the development of a remotely controlled arm, with a total of 7.8 billion yen ($52.8 million) in public funding allocated, including related projects.

“We do not intend to waste the public funds,” Akira Ono, head of TEPCO’s Fukushima No.1 Decommissioning Promotion Company, said at a news conference on the day. “It would be irresponsible if an incident occurs by hastily deploying the robotic arm.”

Even if TEPCO can start the removal by October, that will be about three years behind the original schedule.

However, the utility said that the delay will not affect the overall timeline for decommissioning of the plant, which is set to be completed by 2051.

TEPCO also presented its plan to release treated radioactive water from the plant in fiscal 2024.

Under the plan, roughly 54,600 tons of the treated wastewater, equivalent to about 54 storage tanks, will be discharged into the ocean in seven batches.

The treated water will be diluted with seawater before the release to reduce the concentration of tritium, which cannot be removed via the treatment process.

The estimated total tritium release is around 14 trillion becquerels, falling below the annual limit of 22 trillion becquerels set by TEPCO.

Since August last year, a total of 23,400 tons of treated wastewater from the plant has been discharged into the sea in three releases.

Analyses of seawater and fish in surrounding areas conducted by TEPCO, the government and other institutions have not detected abnormal radiation levels.

There have also been no reported issues with the discharge equipment.

The government and TEPCO have explained that after the treated water is released, empty storage tanks will be removed to construct the necessary facilities for decommissioning the plant.

They said that work to begin dismantling the empty tanks will begin in fiscal 2024.

(This article was written by Keitaro Fukuchi and Ryo Sasaki.)

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