TEN years after Japan’s Fukushima nuclear disaster, life in the region is finally edging back to normal. Following a colossal campaign to remove contaminated soil and wash down buildings and roads in the area, radiation readings above ground are now stable at safe levels.

There is even a sense of a construction boom, although tens of thousands of people have yet to return after being evacuated a decade ago. “Everything is new,” said one resident. “New is good.”

The most striking new features are concrete sea walls that run northwards for 400 kilometres from the coastal city of Iwaki. At four storeys tall, they are twice the size of the ones overwhelmed on 11 March 2011 by a tsunami triggered by a magnitude-9 earthquake. The waves left nearly 20,000 people dead or missing and knocked out the Fukushima Daiichi nuclear plant’s cooling system, triggering a meltdown.

Earthquakes still hit the region, including aftershocks of the cataclysmic 2011 one. Last month, a magnitude-7.3 quake caused damage throughout Fukushima prefecture, but the nuclear power plant reported no abnormalities. Operations to cool the nuclear fuel debris in its containment vessels are still ongoing.

We now have a better idea of what leaked out of the reactors. The flooding of the power plant dispersed lots of radioactive material, including the isotopes caesium-137 and caesium-134, which take 30 and 2 years, respectively, to decay to half their initial amounts. Iodine-131 was also released, but with a half-life of just eight days, it decayed quickly and is no longer detectable in the environment.

A 2013 report by the United Nations Scientific Committee on the Effects of Atomic Radiation said that no radiation-related health effects were expected in the general public in Fukushima. A later study in 2016 looking at the city of Date in Fukushima, which was decontaminated in the years following the accident, found that the clean-up efforts had no noticeable effect on reducing radiation levels, although normal decay and weathering did.

So, was it really necessary to evacuate 154,000 people from the region? Phillip Thomas at the University of Bristol, UK, and his colleagues are unconvinced. In a 2017 study, his team developed a series of tests to examine the impact of relocations after the Fukushima crisis and the Chernobyl nuclear disaster in 1986.

The researchers created a way to calculate the life expectancy saved by moving residents away from areas affected by radiation. They compared this with the cost of relocation and how much this expenditure would affect people’s quality of life in the future. They used this to assess the measures used to mitigate the impact of nuclear accidents.

“We applied a new method, which compares the life expectancy against cost,” says Thomas. “The life expectancy lost by people in the worst-affected village [in Japan] was less than three months.”

Gareth Law at the University of Helsinki in Finland says it was worth being cautious. “I think the evacuation was appropriate: safety first. Understand what the contamination is and assess the problem. Can the levels or forms of contamination harm people? And if it’s safe, then start to allow people to move back.”

No quick fix

People are moving back, but it will still be a long time before the Fukushima Daiichi power plant is fully decommissioned and everyone can return – about 30 to 40 more years – according to the Tokyo Electric Power Company (TEPCO), which operates the plant. Around 330 square kilometres in Fukushima prefecture were designated “difficult-to-return” in 2013, and only 0.54 square kilometres have reopened to date.

“Decommissioning is the most serious issue at the present,” says Satoshi Utsunomiya at Kyushu University, Japan. “They need to remove all materials inside the damaged reactors, which is a mixture of melted nuclear fuels and structure materials emitting extremely high radiation.”

TEPCO had hoped to start that process this year, but it has been stalled by the coronavirus pandemic, which has delayed tests of a robotic arm designed to remove the collapsed fuel.

Another issue is how to reduce the volume of treated coolant water – 1.2 million tonnes tainted with tritium – because the plant is running out of storage space (see “Waste water worries“).

Outside the power plant, areas bordering a forced evacuation zone and once considered a health risk were last year given the all clear for rehabitation. Just north of the power plant, the town of Futaba is now welcoming back former residents, but it remains full of shattered housing, with broken windows revealing abandoned children’s toys, shoes, clothes and kitchen spoons.

Although a few residents have returned to tidy up, many houses lie smashed, spilling their contents onto decaying, weed-choked streets. I spotted a large pheasant gambolling over a zebra crossing, but few signs of normal town life.

Further out is a different matter. On the road south from the town to the power plant, gone are the abandoned fields and homes, shuttered businesses and vast, orderly stacks of tsunami debris along the flat, coastal plains. Where grass and weeds once grew in mud left by the tsunami, now there are new shops, businesses and homes with solar panels, along with paddy fields and landscaped roads.

The return to normality is slow, however. A decade ago, the hotels of a small town called Naraha, just outside the original 20-kilometre exclusion zone, became a home for clean-up workers at the power station. One inn owner, Minoru Yoshida, returned shortly after the disaster and has made a business of accommodating clean-up and construction workers. As one of the few willing to return, he virtually had a monopoly on supplying accommodation in the area. But working newcomers still outnumber returning residents, he says.

“We’ve seen quite a lot return to the areas opened over five years ago. But the recently reopened towns such as Futaba – they’ve had it,” says Yoshida. “Not because of radiation fears so much, but because it’s been 10 years since they left, the young have put down roots elsewhere. It’s a town for the old now.”

There are many incentives to return. Businesses that reopen this year will get roughly 4 million yen (£7,000) from the Japanese government. But population numbers in Fukushima prefecture have only returned to about 20 per cent of 2011 figures since evacuation orders were rescinded. “None here are worried about Daiichi now,” says Yoshida. “We are more concerned about the coronavirus. Besides, for many of us, the Daiichi clean-up is our bread and butter. Things are good.”

Even 10 years on, the stricken Fukushima Daiichi nuclear reactors are constantly bathed in cooling water to keep their radioactive fuel safe. That water is then processed twice to remove 60 types of radioactive materials, leaving just one radioactive element: tritium, an isotope of hydrogen that forms part of the contaminated water molecules themselves.

The Tokyo Electric Power Company, which operates the nuclear plant, is storing the contaminated water for now. There are already 1.2 million tonnes of it kept in more than 1000 massive tanks on site, but the firm is running out of space. One solution is to dump the water into the sea.

“The most realistic process would be to just release the water after dilution, but this will impact fisheries even though the total activity of tritium is within tolerance levels,” says Satoshi Utsunomiya at Kyushu University, Japan.

The International Atomic Energy Agency takes the same view. Last year, its director general Rafael Grossi told the Kyodo news agency that sea dispersal would be “in line with the current practice and best practices internationally”.

But discharge plans have been shelved again and again as neighbouring countries such as South Korea protest and locals worry about reputational damage to industries including agriculture, forest, fishery and tourism.

A panel of experts gathered by the Japanese trade ministry in February 2020 recommended releasing the water before the middle of 2022, when the plant’s storage is expected to have filled up. The Japanese government will make a further announcement on plans for the water after the delayed Tokyo 2020 summer Olympics this year, New Scientist understands.