The Yomiuri ShimbunSteadily progressing with the decommissioning of the reactors at Tokyo Electric Power Company Holdings, Inc.’s Fukushima No. 1 nuclear power plant will accelerate Fukushima Prefecture’s recovery. TEPCO must make safety the top priority when doing this work.
According to a schedule drawn up by the government and TEPCO, fuel from reactor No. 3’s spent nuclear fuel pool is slated to be removed in fiscal 2018. Equipment necessary for this work is already in place.
The large volume of nuclear fuel should not be kept inside the heavily damaged reactor. It is vital to reduce the risks posed by this fuel.
The schedule stipulates that the method for removing molten nuclear fuel from Nos. 1, 2 and 3 reactors — which suffered meltdowns — will be decided in fiscal 2019. To accomplish this, it also will be necessary to more precisely gauge the extent of the damage to the nuclear reactors and the levels of radioactive contamination.
In January, a camera sent in from the side of reactor No. 2 captured images of sediment that appears to be melted fuel at the bottom of the reactor. Moving forward, it is essential to retrieve some of this fuel to confirm its exact condition.
Nearly seven years have passed since the nuclear accident, and the environment at the nuclear plant has improved considerably. Decontamination work within the plant’s grounds has made good progress, and a facility for treating the huge amount of waste generated during work at the site has entered full-scale operation.
There also is an increasing degree of stability in the management of contaminated water at the site, which has long been viewed as a problem. Groundwater that enters the reactor buildings becomes contaminated. To reduce the volume of water flowing into the buildings, groundwater has been pumped up from wells nearby and the water level has been lowered.
Prevent harmful rumors
In addition, the “frozen soil wall” — constructed at a cost of ¥34.5 billion from government coffers — has had some effect in preventing water from seeping into the buildings. The underground wall freezes soil in a perimeter around the building and prevents groundwater from flowing through. The volume of contaminated water generated has declined from about 500 tons per day to about 150 tons.
The frozen soil wall was expected to be a trump card for reducing the volume of contaminated water. While it cannot be counted on to be quite so effective, the government’s Committee on Countermeasures for Contaminated Water Treatment, a panel of experts, on Wednesday positively assessed the overall effort, saying, “A groundwater management system has been constructed.” It is vital to have multiple measures in place to prevent water contamination.
Yet challenges still abound. The committee pointed to the difficulties in dealing with heavy rain at the nuclear plant. Rainfall causes the volume of contaminated water to surge. Efforts to prevent rain from entering through damaged sections of the buildings and through drains must be sped up.
Contaminated water at the plant is treated and all radioactive materials, except tritium, are removed. What to do with this treated water also is a knotty problem. At other nuclear power facilities, treated water is released into the sea in accordance with discharge standards. About 850,000 tons of such water is being stored in tanks on the Fukushima nuclear plant grounds.
At some point, there will be no more room for new tanks. Nuclear Regulation Authority Chairman Toyoshi Fuketa has repeatedly said, “There is no option but to dilute the water and release it into the sea.” The government and TEPCO should not put off making a decision.
They will also need to take steps to thoroughly prevent harmful rumors from spreading, such as by ensuring that the safety of this process is widely known.