Japan has secured final approval from the International Atomic Energy Agency (IAEA) for discharging treated water from the Fukushima Daiichi plant into the Pacific. The measure is central to the plant’s decommissioning but has sparked controversy and questions around safety and transparency.
Why will dirty water spill into the ocean?
The Government of Japan approved the plan in April 2021, formulated alongside the energy company Tokyo Electric Power Company (TEPCO). The facility has accumulated millions of tons of water that became contaminated with radioactive substances after the 2011 earthquake and tsunami that damaged the Fukushima Daiichi site.
The decision to release water into the ocean was driven by storage constraints at nuclear facilities. Alternatives were discarded due to technical complexity or higher costs, leading authorities to choose discharge as the most feasible option at the time.
The plan, developed with the IAEA, envisions progressively releasing more than 1.32 million tons of treated liquid into the Pacific after processing and dilution in seawater to remove most of the highly radioactive substances still present.
Radioactive water?
Radioactive water is produced at the site when cooling water contacts damaged reactors. It passes through a treatment system called ALPS (Advanced Liquid Processing System), which removes 62 types of radioactive elements, with tritium and carbon-14 remaining beyond current removal capabilities, according to Japanese officials.
This cleaning process is repeated as needed within the facility’s piping and processing network until measurements show that the radioactive concentrations meet Japan’s limits and international standards.
Officials say the remaining residues after purification and dilution do not exceed 1,500 becquerels per liter before entering the sea—about one-seventh of the World Health Organization’s guideline for drinking water.
Is dumping safe?
Both the Japanese government and the IAEA argue that the discharge complies with international safety regulations. They note that the water near the discharge site will be monitored to detect any anomalies related to radiological protection and the safety of the nuclear industry.
According to calculations by Japanese authorities and the IAEA, the radioactivity levels in nearby waters will be essentially indistinguishable from typical environmental radiation, leading to the assessment that the radiological impact on people and ecosystems is minimal.
Nevertheless, some voices from the international scientific community, including members of the United States National Association of Marine Laboratories, have urged caution and called for additional data to fully justify the safety of the release.
There are also concerns about potential effects on local fishing communities, Fukushima’s regional economy, and neighboring countries in the Pacific region, including South Korea and China.
Discharge of tritium-contaminated water is standard practice in the nuclear industry in many cases, sometimes at higher concentrations than those anticipated at Fukushima.
When will it happen?
The government has indicated that the discharge could begin this summer from an unspecified date. After the final IAEA report is released, the management team will review its conclusions before deciding whether to proceed with the draining of the liquid.
The vast and continually growing stock of polluted water, together with regulatory limits, means the process could extend over decades and align with the broader dismantling horizon for the plant, estimated between 2040 and 2050.
…