With the government declaring Dec. 16 that Step 2 of the road map for bringing the Fukushima No. 1 nuclear power plant under control has been completed, that starts the long and difficult next stage, which could take decades.
With the government declaring Dec. 16 that Step 2 of the road map for bringing the Fukushima No. 1 nuclear power plant under control has been completed, that starts the long and difficult next stage, which could take decades.
Now begins the difficult processes of decontaminating radiation spewed from the plant and decommissioning the reactors.
The work until now demonstrates that officials will have to be prepared for any possibility.
For example, in November, water that had been decontaminated at the plant was found leaking from hoses. Officials of Tokyo Electric Power Co., the operator of the Fukushima plant, said on Dec. 7 that the leaks were caused by weeds that had poked holes into the plastic hoses.
About 4 kilometers of hoses have been placed on the ground in the Fukushima No. 1 nuclear plant to decontaminate water used to cool the reactor cores.
No plans have yet been drawn up to replace that temporary cooling and recycling system with a more permanent one that could withstand prolonged use.
There has also been no work done on processing the radioactive materials that remain after the cooling water has been decontaminated.
Workers at the Fukushima plant have also had to deal with unexpected localized increases in radiation levels as well as the accumulation of high concentrations of hydrogen gas in piping in the plant.
Decontamination of areas around the plant will also be important because reducing radiation levels is a major precondition for allowing evacuees to return to their homes.
Decontamination can only begin as soon as March because Environment Ministry officials said they need to obtain the approval of residents before workers could remove topsoil and cut tree branches in the yards of their homes.
No decision has yet to be made on where to temporarily store the contaminated topsoil that will be removed.
Even after decontamination work begins, other work to restore social services and roads will also have to be completed before residents could realistically expect to return home.
A problem on an even longer span is the decommissioning of the reactors at the Fukushima plant.
The central government and TEPCO are expected to release a road map for decommissioning on Dec. 21.
Sources said the road map would be made up of three stages. In the first stage that would begin next year and last for about three years, spent nuclear fuel would be removed from the storage pools in the reactors. In the second stage, extending from four years down the road to about a decade later, work would be done to repair the containment vessels to allow for the removal of nuclear fuel from the reactor cores.
The main task for the final stage that would commence after about 11 years would be the removal of the melted fuel.
The final stage will involve coming up with an entirely new way of removing the fuel because much of it has likely leaked outside the pressure vessel, an unprecedented situation.
Because TEPCO officials have no idea what the situation within the reactor is actually like, the methods and equipment to be used for removing the fuel will have to take into consideration the extent to which the fuel has melted and leaked out of the pressure vessel.
For that reason, the road map to be compiled for decommissioning is more like a set of objectives than a plan for dealing with the situation at the Fukushima nuclear plant.