Japan’s plans to release treated water stored at the Fukushima Daiichi nuclear power station into the sea are deemed consistent with International Atomic Energy Agency (IAEA) safety standards. The agency has determined that the two options under consideration for disposing of this water — discharge into the sea and via vapor release — are both technically feasible. These methods are routinely used by operating nuclear power plants worldwide under specific regulatory authorizations based on safety and environmental impact assessments.

The Fukushima Daiichi nuclear power station was seriously damaged in 2011 by an earthquake and tsunami that devastated the site. Water stored at the plant has been treated through an advanced liquid processing system (ALPS) to remove almost all radioactivity aside from tritium. Before discharging, operators will dilute the water to bring the tritium to below regulatory standards.

The ALPS system is a pumping and filtration system that uses a series of chemical reactions to remove 62 radionuclides from contaminated water that had accumulated at the plant. The radioactive material removed from the water is captured in filters that are stored on site in high integrity containers.

The IAEA safety review will continue during the discharge phase and the agency will maintain a continuous on-site presence and provide live online monitoring on its website from the discharge facility.