Japan Begins Release of Treated Nuclear Wastewater Into the Pacific Ocean

Twelve years after the Fukushima Daiichi nuclear disaster, the move is a polarizing step toward decommissioning the defunct power plant

rows of blue, white and grey tanks next to the coast
The tanks used for storing treated water at the Fukushima Daiichi Nuclear Power Plant in Japan are almost at capacity. STR / JIJI Press / AFP via Getty Images

In a decision steeped in controversy, Japan started releasing radioactive water from its Fukushima No. 1 nuclear power plant into the Pacific Ocean on Thursday.

The move is a critical step in decommissioning the Fukushima Daiichi nuclear power plant, which the Japanese government has been struggling to clean up since 2011, when a magnitude 9.0 earthquake triggered a tsunami that caused the catastrophic meltdown of three of the plant’s nuclear reactors.

The release began at 1:03 p.m. local time, and so far, no abnormalities have been reported.

“We see this as a very important moment in the process and understand that there are many people interested in the project, so we would like to proceed putting the greatest importance on safety,” Keisuke Matsuo, a representative for the plant’s operator, Tokyo Electric Power Company Holdings (TEPCO), said to reporters shortly after the release began, per Gabriele Ninivaggi of the Japan Times.

In the aftermath of the 2011 earthquake, workers flushed the damaged nuclear reactors with water to prevent further emergencies—but that water accumulated contaminants, report NPR’s Geoff Brumfiel and Kat Lonsdorf. Radioactive materials have seeped into groundwater at the site, and water used to cool the reactors to this day continues to pile up.

This radioactive liquid has been stored at the plant ever since, filling more than 1,000 tanks to 98 percent of their 1.37-million-ton holding capacity. Officials say the tanks need to be emptied to build the facilities needed to continue decommissioning the plant, per Mari Yamaguchi of the Associated Press (AP).

So, in 2021, the Japanese government approved the water discharge plan, and it earned a green light from the United Nations nuclear watchdog organization, the International Atomic Energy Agency (IAEA), last month. The IAEA concluded the plan would result in a “negligible” impact on people and the environment. However, fisheries and fish consumers have raised concerns.

Lots of the radioactive contaminants can be filtered out of the water, but tritium—a radioactive isotope of hydrogen that forms part of the water molecule—cannot be removed. Instead, TEPCO simply dilutes the tritium-contaminated wastewater. The utility reported on Thursday that the water being discharged into the ocean contains 63 becquerels of tritium per liter, far below the 10,000 becquerels of tritium per liter set as the maximum for drinking water by the World Health Organization, according to Reuters’ Sakura Murakami.

Edwin Lyman, director of nuclear power safety at the Union of Concerned Scientists, tells NPR the waste generated by operating nuclear reactors is most likely worse than this water. “In my view, I think that their current plan, unfortunately, is probably the least bad of a bunch of bad options,” he says to the publication.

On Tuesday, officials conducted a trial run of the release: They diluted one ton of the contaminated water with 1,200 tons of seawater in a coastal area, then sampled it two days later to make sure it was safe.

Roughly 460 tons of contaminated water were set to be released on Thursday, per the AP, discharged at a slow pace through an undersea tunnel and into an area of the ocean roughly 0.6 miles away from the coast. The IAEA will continue to monitor the process, which will last for decades.

“It’s a very political issue of disposing radiation into the sea,” Tony Hooker, director of the Center for Radiation Research, Education, Innovation at the University of Adelaide in Australia, says to the AP. “I understand people’s concerns, and that’s because we as scientists have not explained it in a very good way, and we need to do more education.”

people holding signs in a protest with words in Korean; English words read "SOS!! Pacific Ocean!"
Protesters in South Korea oppose Japan's release of the treated, radioactive water. Chung Sung-Jun / Getty Images

Despite assurances, the decision has incited backlash on the global stage. China responded to the release Thursday with a ban, effective immediately, on imports of all aquatic products from Japan. Prior, China had been conducting rigorous inspections of seafood from Japan, delaying items’ approval at customs for weeks.

In South Korea, protests and panic sales of sea salt have continued for months, while Hong Kong and Macau have issued their own bans on Japanese seafood from ten regions. China and Hong Kong made up 42 percent of the market for Japan’s seafood exports in 2022, Reuters reports.

Fisheries in Fukushima have expressed their ire as well—they never fully recovered after the nuclear disaster, with catch sizes totaling about one-fifth of what they were before the meltdown, in part due to a smaller fishing population.

On Sunday, Japan’s Prime Minister Fumio Kishida pledged to support Fukushima’s fishing population financially. And after China announced its ban, TEPCO president Tomoaki Kobayakawa said the utility would compensate Japanese business owners for damages incurred by export bans, per the AP.

Fukushima’s fishing community is experiencing “mounting anxiety,” the head of the Japan Fisheries Co-operative says in a statement, per Reuters. “All we want is to be able to continue fishing.”

TEPCO plans to release 31,200 tons of wastewater by the end of March 2024 before increasing the scale of the process. The IAEA launched a real-time website for public monitoring of the project.

Get the latest stories in your inbox every weekday.