On March 11, 2011, a magnitude 9 earthquake hit Japan, causing a massive tsunami that flooded the reactors of the Fukushima Daiichi nuclear power plant. 

The most severe nuclear accident since Chernobyl sparked a new wave of anti-nuclear sentiment and most of the country's nuclear plants were taken offline for urgent safety checks. 

Within days of the disaster, thousands of kilometers away, the German government announced a 10-year plan to phase out nuclear power, having been lobbied on the issue for decades by environmental campaigners.

New anxieties supplant radiation threat

More than 11 years on from the disaster, despite Japan sitting firmly in the so-called ring of fire — a path along the Pacific Ocean characterized by active volcanoes and frequent, earthquakes — this summer Tokyo recommitted to nuclear power.

Prime Minister Fumio Kishida said that Japan would restart up to nine nuclear reactors by winter and seven others by next summer, citing the need for secure energy supplies in the wake of the Ukraine war and help meet Japan's net-zero targets.

"Russia's invasion of Ukraine has vastly transformed the world’s energy landscape. To overcome an imminent crisis caused by a power supply crunch, we must take the utmost steps to mobilize all possible policies in the coming years and prepare for any emergency," Kishida warned in August.

Longer-term proposals announced since then include extending the lifespan of nuclear reactors beyond the current 60 years —  which some scientists say will be a lower risk if you count the years they were offline — and developing new smaller, safer, nuclear reactors.

"You get the sense that Japan's political leaders were biding their time, waiting for public acceptance to improve and the broader context to change before they recommitted to nuclear technology," David Hess, policy analyst at the World Nuclear Association, told DW.

Europe, Asia tussle over energy supplies

The context has changed. Gas supplies to Asia were already tight last winter due to the aftereffects of the COVID-19 pandemic and the global energy crisis further spiked natural gas prices to record highs as Asian and European countries battled to secure supplies of liquefied natural gas (LNG) as an alternative to Russian pipeline gas.

Behind the Japanese decision is also the country's historic reliance on nuclear due to a lack of conventional energy resources, like oil and gas.

"Japan doesn't have much coal and oil, so they've always imported a very large percentage of their energy demand — not only electricity [also transport and heating]," Jim Smith, a professor in environmental sciences at the UK's University of Portsmouth, told DW.

Before the Fukushima meltdown, about a third of Japan's power generation came from nuclear. By 2020, the figure had dropped to less than 5%. Tokyo has set a new target for nuclear to provide up to 22% of its electricity supply by 2030.

The limits of intermittent renewable energies and lack of available land to massively expand hydroelectric, solar and wind power were also cited for nuclear's planned resurgence. Even so, the government last year raised the target for renewables in electricity generation to 36-38% by 2030, a doubling from 2019.

'Global shift' to nuclear?

Hess from the World Nuclear Association told DW that Japan's decision was part of a "global shift" back toward atomic power, citing recent decisions by Poland, the Czech Republic, Britain, Sweden and France. He noted how bipartisan support is also growing for nuclear in the US.

"A whole group of newcomer countries are making progress towards building their first reactors, including Egypt, Uzbekistan and the Philippines," he said. "If anything, Japan has been slow to react. So the momentum is perhaps helping to convince them that nuclear energy is being broadly embraced globally as a long-term carbon climate and energy security solution."

Hess also thinks that more than a decade after Fukushima, and with Japan reaffirming its commitment, Germany's nuclear phaseout seems "extremely out of place." 

Germany, however, is not the only country still phasing out nuclear — despite Berlin ordering a short-term extension in the life of three remaining nuclear plants this winter due to the energy crisis. Spain and Switzerland have also announced plans to stop nuclear power generation over the next decade. Other nations like Australia, Austria, Denmark, Ireland, Italy, Malaysia, Portugal and Serbia remain opposed to nuclear power.

The European Union recently determined that nuclear could be labeled as green energy, to help unlock potentially billions of euros in funding from environmentally minded investors.

Safety increased, better risk assessment

Japan — and the nuclear industry — have learned many hard lessons from Fukushima, particularly in relation to extreme flooding events and the loss of emergency power. Although a seawall was built around the plant, it was not high enough to contain the 13-14 meter (14-15 yard) tsunami waves. Diesel backup generators in the basement, which were meant to cool the reactors in an emergency, flooded. 

"It's obvious in retrospect that the design was significantly flawed. The plants built in the 1970s weren't sufficiently designed with an earthquake zone in mind," said Smith. He said that the new generation of nuclear plants, including those by French energy giant EDF, are described as "passively safe" meaning that they "couldn't have a meltdown like the one that happened at Fukushima."

Smith also noted that the worst fears over radiation from the accident were unfounded, as victims "got lower doses than people get from natural radiation." He said it would be statistically unlikely to see increased cancers from the disaster.

Lawyers for the victims who have filed lawsuits for compensation say the incidence of diagnosed or suspected thyroid cancer is 77 per 100,000 people, significantly higher than the usual 1-2 per million. The Japanese government disputes this.

Nuclear disasters do leave huge areas of land out of bounds for hundreds if not thousands of years, and at Fukushima, more than 150,000 people had to be evacuated, nearly a fifth of them permanently. 

"That's true even of Chernobyl," Smith said. "Although the health impacts of Chernobyl were much worse than Fukushima, the social and economic impacts are worse than the direct health impact."

Edited by: Uwe Hessler