Photo/Illutration Decommissioning work continues at the No. 3 reactor at Tokyo Electric Power Co.’s Fukushima No. 1 nuclear power plant in Okuma, Fukushima Prefecture, on Jan. 24. (Asahi Shimbun file photo)

Despite another delay in the start of fuel debris removal at the crippled Fukushima No. 1 nuclear power plant, the plant operator insists that it still aims to complete decommissioning by 2051, which at least one expert calls unrealistic.

Shunji Matsuoka, a professor of environmental economics and policy studies at Waseda University, said Tokyo Electric Power Co.'s timetable should be altered to reflect the reality.

“Who really believes all 880 tons of debris can be removed in the 14 years between 2037 and 2051?" he said. "Maintaining an unrealistic goal is not good when considering Fukushima's recovery.”

In the latest setback, the Nuclear Damage Compensation and Decommissioning Facilitation Corp. announced on July 29 that removal of radioactive fuel from one of the reactors at the  Fukushima No. 1 plant will not begin for at least another 12 years. 

That will delay the start of large-scale removal until after 2037.

However, at a news conference that day, Akira Ono, president of Fukushima Daiichi Decontamination & Decommissioning Engineering Co., said, “There is no situation that would require abandoning the target time frame for decommissioning.” 

The decommissioning is being carried out by TEPCO based on a mid- to long-term road map formulated with the central government in December 2011. Even before this delay, many processes, such as the removal of spent fuel, had already fallen behind schedule.

Although the road map has been revised several times, the overall goal of completing decommissioning by 2051 has remained unchanged.

In the latest update, TEPCO disclosed the scheduled start time for debris removal from the plant’s No. 3 reactor, but did not specify the duration of the work, citing “uncertainties.”

An estimated 880 tons of fuel debris remains in three reactors at the plant, but for the No. 1 and No. 2 reactors, neither the process nor the method of removal has yet been decided.

Ono said that preparatory work for No. 1 and No. 2 reactors would be studied over the next one to two years. He said that “simultaneously removing debris from all three reactors is not impossible,” and “we want to consider how to achieve that.”

The method that TEPCO proposed on July 29 is based on the guidance provided by the Nuclear Damage Compensation and Decommissioning Facilitation Corp. (NDF) in March 2024.

The NDF’s committees of experts considered three methods for removal: partial submersion, which would spray water on the debris while removing it; full submersion, which would fill the reactor with water; and the filling and solidification method, which would solidify the debris with filler material and then scrape it out.

The full submersion method is difficult to implement because of the heavily damaged No. 3 reactor building. 

Therefore, the NDF recommended that TEPCO combine the partial submersion method with the filling and solidification method, which can suppress radiation levels.

TEPCO accepted the proposal and will adopt this approach.

TEPCO said it will reduce the structural burden by downsizing the equipment to be installed atop the reactor building, and will remove the debris out from the side of the reactor.

The company said it will verify this method over the next one to two years and revise it if necessary.

(This article was written by Yusuke Ogawa and Fumi Yada.)

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