Japan plans to release more than 1 million metric tons of treated radioactive water from the Fukushima nuclear plant into the Pacific Ocean by the end of August. After years of debate, and despite a green light from the International Atomic Energy Agency (IAEA), the plan continues to arouse fear in the local population and in neighboring 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 Japanese daily newspaper Asahi Shimbun revealed an upcoming release without a specific date.
The release of contaminated water by Tokyo Electric Power Co. (TEPCO) has been on the cards since 2018 but it was repeatedly postponed until it finally received an endorsement from the International Atomic Energy Agency in early July. After two years of review, five review missions to Japan, six technical reports and five ground missions, the international nuclear watchdog said the discharges of treated water were in line with the agency’s safety standards, with “negligible radiological effects on people and the environment”. The green light, which clears the way for the completion of the project, was greeted with skepticism by some members of the scientific community and with the anger of many local fishermen who fear that consumers will avoid their products.
Storage capacities have reached their limits
On March 11, 2011, three reactor cores at the Fukushima Daiichi nuclear power plant experienced a meltdown, leaving northeastern Japan in ruins and adding to a nuclear emergency caused by the earthquake and tsunami. . Since then, a lot of water has been used to cool the fuel in the nuclear reactors every day, while hundreds of thousands of liters of rainwater or ground water have entered the site.
Japanese authorities initially decided to store the contaminated water in large tanks, but have now run out of space. About 1,000 tanks were built to contain the current 1.3 million tons of waste water. The Japanese authorities have warned that storage capacities are close to their limit and will reach saturation in 2024. The power plant is also located in a region with a high earthquake risk – meaning that a new earthquake could causing the tanks to leak.
Read moreFukushima fallout: A decade after Japan’s nuclear disaster
Filter contaminated water
To avoid such an accident, the Japanese government decided to gradually release millions of tons of water into the Pacific Ocean over the next 30 years. The process is simple: the water is set to be released one kilometer away from the coast of Fukushima Prefecture through an underwater tunnel.
Releasing treated wastewater into the ocean is standard practice at nuclear plants around the world. Water is usually made to surround a nuclear reactor to absorb heat, which makes it possible to trigger the turbines and generate electricity. In the process, the water is filled with radioactive compounds, but it is treated before being released into the sea or rivers.
“In Fukushima, however, the situation is very different because it is a damaged plant,” said Jean-Christophe Gariel, deputy director in charge of health and environment at France’s Institute for Radiological Protection and Nuclear Safety (IRSN).
“This time, part of the stored water is poured directly into the reactors to cool them down,” Gariel added. “Not like the water from ours [French] nuclear plants, [theirs] filled with many radioactive compounds, known as radionuclides.”
Before releasing the water into the sea, the challenge is to remove most of the radioactive materials. To do this, the operator of Fukushima, Tepco, uses a powerful filter system called ALPS (Advanced Liquid Processing System). “This makes it possible to eliminate a large part of these radioactive substances, which exist only as traces,” said Gariel.
“On the other hand, like our own power plants, one component remains: tritium, which cannot be eliminated,” he added. This substance is constantly 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 further limit the risks, the water is diluted with a lot of seawater to lower the tritium concentration as much as possible,” explained Gariel.
During the most recent test of the water tanks in March, the Japan Atomic Energy Agency detected 40 radionuclides. After treatment, the concentration of water is lower than the accepted standards for 39 – all of them, except tritium. The level of the latter reached 140,000 becquerels per liter (Bq/L) – while the regulatory concentration limit for discharge into the sea is set at 60,000 Bq/L in Japan. After the final dilution step, however, the tritium level was reduced to 1,500 Bq/L.
“Simply put, while the water from the Fukushima reservoirs is more contaminated than the water that comes from [French] power stations, after treatment and smelting, it’s the same everywhere,” says Jean-Christophe Gariel.
‘It’s like diluting whiskey with Coke‘
However these standards and figures must be changed and carefully, with set thresholds that vary from one country to another. For example, France sets its tritium limit at 100 Bq/L, while the WHO sets it at 10,000 Bq/L.
When it comes to diluting tritium, some environmentalists argue that it’s like “diluting whiskey with coke”: the presence of coke doesn’t mean there’s less alcohol. Similarly, the amount of tritium in the ocean remains the same; it is only distributed in more water.
Within the scientific community, the safety validity of Japan’s planned water release is widely debated. The Woods Hole Oceanographic Institution (WHOI), based in the United States, has often expressed concerns about the project’s impact on the environment. The Institute expressed its opposition once again to the Japanese project in December 2022, lamenting the failure to measure concentration rates in all plant reservoirs.
However for Jim Smith, professor of environmental science at the University of Portsmouth in the United Kingdom, releasing waste into the sea “is the best option”. The professor, who studies the consequences of radioactive pollutants, argued in an article published in The Conversation that “on the large scale of the environmental problems we face, the release of dirty water from Fukushima is small.”
An eminently political subject
“This topic is very political. It shows the desire of the Japanese government to make the Fukushima region an example of resilience after a nuclear accident,” said Cécile Asanuma-Brice, a researcher at CNRS in France and co-director of the MITATE Lab, which studies the consequences of the Fukushima disaster.
“This is the background of the Japanese government’s reconstruction policy, which includes dismantling the plant and reopening the area to housing,” Asanuma-Brice explained. “The plant can only be dismantled once they have removed the contaminated water, according to the latest statement by the Minister of Economy and Industry, Yasutoshi Nishimura.”
In order to realize the project, the government also had to face continued opposition from the local population, especially from the fishermen’s unions. “Because [the fishermen’s unions], which represents 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 a negative image within the years, regionally and internationally. They have recently begun to recover and restore a dynamic economic activity. With the project to release the contaminated water, they fear that their image will be damaged again and their products will be avoided by consumers.”
Over the years, many alternative solutions have been explored with varying degrees of attention by the authorities. “One of them seems to have obtained permission from the local population – to build new reservoirs or even to install them underground and continue to store the contaminated water until the radioactivity disappears in the future years,” said Asanuma-Brice. The idea was quickly dismissed by the government, which was deemed too expensive.
Apart from domestic opposition, the Japanese government also has to deal with mistrust in other Pacific countries, especially from China. Following the green light given by the IAEA in early July, Beijing announced an upcoming ban on the import of food products from some Japanese prefectures, including Fukushima, for “security reasons “.
This article was translated from original in French.