Japan’s Fukushima water release plan fuels fear despite IAEA backing

After years of debate, and despite a green light from the International Atomic Energy Agency (IAEA), the plan continues to stoke fears among the local population and in nearby countries.

Twelve years after the triple catastrophe – earthquake, tsunami, reactor meltdown – that struck the Fukushima Daiichi nuclear power station in 2011, Japan is preparing to release part of the treated wastewater from the stricken plant into the Pacific Ocean this month. A recent article from the daily Japanese newspaper Asahi Shimbun revealed the upcoming release without specifying a date.

The release of contaminated water by the Tokyo Electric Power Co. (TEPCO) has been on the cards since 2018 but it was repeatedly postponed until it finally received endorsement from the International Atomic Energy Agency in early July. After a two-year review, five review missions to Japan, six technical reports and five missions on the ground, the international nuclear watchdog said the discharges of the treated water were consistent with the agency’s safety standards, with "negligible radiological impact to people and the environment".

The green light, which cleared the path for the completion of the project, was greeted with scepticism by some members of the scientific community and with animosity by many local fishermen who fear that consumers will shun their products.

Storage capacities reaching their limit

On March 11, 2011, the three reactor cores of the Fukushima Daiichi nuclear power plant experienced a meltdown, leaving northeast Japan devastated and adding a nuclear emergency to the devastation caused by the earthquake and tsunami. Since then, massive quantities of water have been used to cool down the nuclear reactors’ fuel rods every day, while hundreds of thousands of litres of rainwater or groundwater have entered the site.

Japanese authorities initially decided to store the contaminated water in huge tanks, but are now running out of space. Some 1,000 tanks were built to contain what is now 1.3 million tonnes of wastewater. Japanese authorities have warned that storage capacities are nearing their limit and will reach saturation by 2024. The power plant is also located in a region with a high earthquake risk – meaning that a new tremor could cause the tanks to leak.

Filtering the contaminated water

To avoid such an accident, the Japanese government has decided to gradually discharge millions of tonnes of water into the Pacific Ocean over the next 30 years. The process is simple: the water is set to be released one kilometre away from the coast of Fukushima Prefecture via underwater tunnel.

Releasing treated wastewater into the ocean is a routine practice for nuclear plants all over the world. Water is usually made to circulate around a nuclear reactor to absorb heat, making it possible to trigger turbines and produce electricity. In the process, the water becomes loaded with radioactive compounds, but it is then treated before being released into the sea or rivers.

"In Fukushima, however, the situation is very different since it is a damaged plant," said Jean-Christophe Gariel, deputy director in charge of health and the environment at France's Institute for Radiological Protection and Nuclear Safety (IRSN).

"This time, part of the stored water was poured directly onto the reactors in order to cool them," Gariel added. "Unlike the water from our [French] nuclear plants, [theirs] became loaded with many radioactive compounds, known as radionuclides."

Before discharging the water into the sea, the challenge is therefore to remove most of the radioactive materials. To do this, Fukushima's operator, Tepco, uses a powerful filtration system called ALPS (Advanced Liquid Processing System). "This makes it possible to eliminate a large part of these radioactive substances, which are only present as traces," said Gariel.

"On the other hand, as in our own power plants, one component remains: tritium, which cannot be eliminated," he added. This substance is routinely produced by nuclear reactors and released by power plants around the world. While it is considered relatively harmless, it is often blamed for increasing the risk of cancer. "To limit the risks even further, the water will be diluted in a large quantity of seawater to lower the concentration of tritium as much as possible," Gariel explained.

"The plant can only be dismantled once they have got rid of these contaminated waters, according to the latest statements by the Minister of Economy and Industry, Yasutoshi Nishimura."

To carry out the project, the government must also deal with persistent opposition from the local population, especially that of the fishermen's unions. "For [the fishermen's unions], who represent an important part of the country's economy, the question is not so much whether their concerns are justified or not," said Asanuma-Brice. "After the accident, they suffered from a negative image for years, both in the region and internationally. They had just started recovering and regaining a dynamic economic activity. With the project to release the contaminated water, they fear their image will be damaged again and their products shunned by consumers."

Over the years, several alternative solutions have been examined with varying degrees of attention by the authorities. "One of them seems to have gained approval from the local population – that of building new reservoirs or even installing them underground and continuing to store contaminated water until it loses radioactivity in the coming years," said Asanuma-Brice. The idea was rapidly dismissed by the government, which deemed it too expensive.

In addition to the local opposition, the Japanese government will also have to deal with mistrust from other Pacific countries, particularly from China. Following the green light granted by the IAEA in early July, Beijing announced a forthcoming ban on the import of food products from certain Japanese prefectures, including Fukushima, for "security reasons".