The Environment Ministry demonstrates an experiment on recycling contaminated soil, shown in black in the center, in Minami-Soma, Fukushima Prefecture, on May 17.
MINAMI-SOMA, Fukushima Prefecture–In an apparent attempt to quell fears, the Environment Ministry on May 17 showed how it will recycle radioactive soil in construction projects to reduce the growing piles of widely abhorred contaminated debris.
In the demonstration to media representatives here, the ministry measured radioactivity levels of bags of soil collected in decontamination work around the stricken Fukushima No. 1 nuclear power plant, and sorted the earth from other garbage.
Using soil with readings up to 3,000 becquerels of radioactive cesium per kilogram, the ministry plans to create a 5-meter-tall mound measuring 20 meters by 80 meters. Such mounds could be used, for example, as foundations for seawalls and roads in Fukushima Prefecture and elsewhere.
Testing of the methods started on April 24.
After confirming the safety, the ministry wants to promote the use of the recycled soil.
Radioactive debris from the cleanup around the nuclear plant will be stored at interim facilities to be built in Futaba and Okuma, the two towns that host the nuclear plant. The government seeks to move the contaminated debris outside the prefecture for final disposal by 2045.
The government had a difficult time finding municipalities willing to take in the radioactive soil on an interim basis. And safety concerns have already been raised about the ministry’s plan to recycle the radioactive soil.
The cleanup has already collected about 16 million cubic meters of contaminated soil.
Japan’s Environment Ministry is studying the possibility of using some screened soil cleared from Fukushima Prefecture after the 2011 nuclear power plant accident in public works projects.
The Japanese government says, within the next 30 years, it plans to dispose of some 22 million cubic meters of soil and other waste that will be removed from the prefecture as part of the decontamination effort.
To make the job easier, the Ministry hopes to use soil with acceptable levels of radioactive material to build roads, embankments and parks.
The ministry began testing the feasibility of such projects last month at a temporary storage site in Minami Soma, Fukushima Prefecture. The process was shown to the media on Wednesday.
The experiment involves sifting the soil to remove rocks, leaves and branches, then entering it into a machine that measures the level of radioactive substances. The soil is then piled into mounds.
Ministry officials will monitor radiation levels in the air and groundwater around the mounds.
They plan to draw up guidelines for local governments and construction workers by April next year.
The ministry says it aims to use soil with up to 6,000 becquerels per kilogram of radioactive substances in roads and embankments, and up to 4,000 becquerels in parks.
But residents in Minami Soma have requested that for the experiment, the Ministry only use soil with up to 3,000 becquerels per kilogram.
As a result, the officials are unable to test whether soil with higher levels of contamination is safe for recycling.
The project also raises questions about the long-term monitoring of public works built with contaminated soil, and how the Ministry will win the support of people who live nearby.
Workers move big black plastic bags containing radiated soil. Fukushima prefecture, near Fukushima Daiichi nuclear power plant.
Soil from the Fukushima prefecture may be used as landfill for the creation of “green areas” in Japan, a government panel has proposed, facing potential public backlash over fears of exposure to residual radiation from the decontaminated earth.
The advisory panel of the Environment Ministry on Monday proposed reusing soil that was contaminated during the Fukushima nuclear meltdown of 2011 as part of future landfills designated for public use, Kyodo news reported.
In its proposal, the environmental panel avoided openly using the word “park” and instead said “green space,” apparently to avoid a premature public outcry, Mainichi Shimbun reported.
Following an inquiry from the news outlet, the Ministry of the Environment clarified that “parks are included in the green space.”
In addition to decontaminating and recycling the tainted earth for new parks, the ministry also stressed the need to create a new organization that will be tasked with gaining public trust about the prospects of such modes of recycling.
To calm immediate public concerns, the panel said the decontaminated soil will be used away from residential areas and will be covered with a separate level of vegetation to meet government guidelines approved last year.
In June last year, the Ministry of the Environment decided to reuse contaminated soil with radioactive cesium concentration between 5,000 to 8,000 becquerels per kilogram for public works such as nationwide roads and tidal banks.
Under these guidelines, which can now be extended to be used for the parks, the tainted soil shall be covered with clean earth, concrete or other materials.
Such a landfill, the government said at the time, will not cause harm to nearby residents as they will suffer exposure less than 0.01 mSv a year after the construction is completed.
The Fukushima Daiichi nuclear power plant suffered a blackout and subsequent failure of its cooling systems in March 2011, when it was hit by an earthquake and a killer tsunami that knocked out the facility, spewing radiation and forcing 160,000 people to flee their homes. Three of the plant’s six reactors were hit by meltdowns, making the Fukushima nuclear disaster the worst since the Chernobyl catastrophe in 1986.
Gov’t proposes reusing Fukushima’s decontaminated soil on green land
The Environment Ministry on Monday proposed reusing decontaminated soil from disaster-hit Fukushima Prefecture as landfill for parks and green areas.
At a meeting of an advisory panel, the ministry also called for launching a new organization to map out plans on how to gain public understanding about the reuse of decontaminated soil, ministry officials said.
The proposals come at a time when Fukushima Prefecture faces a shortage of soil due to the decontamination work following the 2011 nuclear meltdown.
The government-backed Riken research institute is set to launch experiments on converting radioactive substances contained in high-level nuclear waste generated at atomic power stations into precious metals starting fiscal 2018, it has been learned.
The method, which is dubbed “modern alchemy,” is said to be theoretically viable but hasn’t been put into practical use. If realized, the formula is expected to contribute to trimming nuclear waste and even making effective use of it.
The experiment will be part of the Cabinet Office’s program to promote innovative research and development, called “Impulsing Paradigm Change through Disruptive Technologies (ImPACT)” program. In the initial stage of the demonstration experiment, palladium-107, a radioactive material contained in nuclear waste and whose half-life is 6.5 million years, will be turned into nontoxic palladium-106, which is commonly used in dental therapy, jewelry goods and exhaust gas purification catalysts.
Using an accelerator at the Riken Nishina Center for Accelerator-Based Science in Wako, Saitama Prefecture, the scientists will attempt to convert palladium-107 into palladium-106 by irradiating the former with deuteron beams, in what is called the “nuclear transformation” process. The experiment is set to be the world’s first of its kind on nuclear transformation of palladium, according to Riken officials.
The researchers will compile the outcome of the experiment as early as the fall of 2018 after confirming the ratio of palladium successfully transformed and other results.
As nuclear waste is highly radioactive, the government is currently looking into methods to isolate such waste deep into the ground after sealing it in specially designed containers. If the nuclear transformation process proves viable, it could contribute to reducing nuclear waste and making efficient use of it.
It remains to be seen whether nuclear transformation will prove successful just as in theory and if the process can be turned into practical use at a low cost. In the past, a nuclear transformation experiment was carried out on minor actinides, or “heavy” nuclear waste, at the Joyo experimental fast reactor in Oarai, Ibaraki Prefecture, but the upcoming experiment will be the country’s first using fission products, or “light” nuclear waste.
ImPACT program manager Reiko Fujita said, “We are still at the basic research stage and are far from putting it into practical use. We will, however, move a step forward if we manage to obtain data through our experiment.”
Bags containing contaminated soil and other materials produced through decontamination work are seen at a provisional storage site in Tomioka, Fukushima Prefecture.
The Nuclear Regulation Authority (NRA) has raised questions about the Environment Ministry’s proposal to reuse radioactive soil resulting from decontamination work around the crippled Fukushima No. 1 Nuclear Power Plant due to the insufficiency of information on how such material would be managed, it has been learned.
As the ministry has not provided a sufficient amount of information, the nuclear watchdog has not allowed the ministry to seek advice from its Radiation Council — a necessary step in determining standards for radiation exposure associated with the reuse of contaminated materials.
The Ministry of the Environment discussed the reuse of contaminated soil in closed-door meetings with radiation experts between January and May last year. The standard for the reuse of such materials as metal produced in the process of decommissioning nuclear reactors is set at 100 becquerels of radioactive cesium per kilogram. Materials with a contamination level topping 8,000 becquerels are handled as “designated waste” requiring special treatment. In examining the reuse of contaminated soil, the ministry in June decided on a policy of reusing soil containing up to 8,000 becquerels of radioactive cesium per kilogram as a base for roads with concrete coverings.
According to sources close to the matter, the ministry sounded the NRA out on consulting with the Radiation Council over the upper limit of 8,000 becquerels and other issues. An official from the NRA requested the ministry to provide a detailed explanation on how such soil would be handled, including the prospect of when the ministry would end its management of the reused soil, and how it would prevent illegal dumping. The official then told the ministry that the rule of 100-becquerel-per-kilogram rule would need to be guaranteed if contaminated soil were reused without ministry oversight.
The official is also said to have expressed concerns over the ministry plan, questioning the possibility of contaminated soil being used in somebody’s yard in a regular neighborhood. Since the ministry failed to respond with a detailed explanation, the NRA did not allow the ministry to consult with the Radiation Council.
Government bodies are required to consult with the council under law when establishing standards for prevention of radiation hazards. It was the Radiation Council that set up the 8,000-becquerel rule for designated waste.
An official from the NRA’s Radiation Protection and Safeguards Division told the Mainichi Shimbun, “We told the ministry that unless it provides a detailed explanation on how contaminated soil would be used and on how it will manage such material, we cannot judge if its plan would be safe.”