The government and Tokyo Electric Power Company Holdings Inc. decided Tuesday to further delay the removal of spent nuclear fuel left near two of the three reactors that suffered meltdowns at the Fukushima No. 1 nuclear plant.
In the road map for decommissioning the plant, revised for the fourth time since it was first crafted in 2011, highly radioactive spent fuel will be extracted from the cooling pools of reactors 1 and 2 starting in fiscal 2023 instead of fiscal 2020.
The decision marks the third delay for the removal plan, with the last adjustment coming in June 2015. The government said new technical issues and the need to take safety precautions led to the latest change.
The cleanup process is set to be completed in around 30 to 40 years.
Spent fuel removal at the plant’s reactor 3 will go ahead in fiscal 2018 as planned, having already been pushed back earlier this year.
In the decommissioning process, the removal of fuel rod assemblies from the spent fuel pools in reactor buildings is one of the key steps before extracting melted fuel debris. Reactors 1, 2 and 3 suffered core meltdowns following the March 2011 earthquake and tsunami disaster.
The removal of melted fuel debris has also been delayed, with an extraction plan set to be decided in fiscal 2019, pushed back from the first half of fiscal 2018.
Despite the delay in finalizing specific methods, the road map maintains a 2021 start for debris extraction, the most challenging part of the decommissioning process.
A method currently considered feasible by the government involves removing debris from the sides of the reactors after partially filling them with water.
The road map newly sets the goal of cutting the amount of underground water at the plant to address contaminated water buildup. Underground water — which gets mixed with accumulated radioactive water generated in the process of cooling the damaged reactors — is to be cut to around 150 tons per day in 2020 from the current 200 tons.
The road map does not mention a specific schedule for the disposal of processed water that still contains radioactive tritium.
The plan was first crafted in December 2011 in the wake of the meltdowns, the world’s worst nuclear crisis since the 1986 Chernobyl disaster.
Attempts have been made to confirm the situation inside the damaged reactors using specialized robots. A survey in July this year captured for the first time images of what is likely to be melted nuclear fuel at the bottom of reactor 3.
Isamu Kaneda, deputy mayor of the Fukushima Prefecture town of Futaba, expressed regret over the delay.
“The town’s rebuilding depends on the development of decommissioning. It’s unfortunate,” Kaneda said. “But at the same time, the decommissioning process is an unprecedented project. It needs to be conducted carefully, so we can’t just ask them to speed it up.”