Discharge of water from Fukushima nuclear plant meets IAEA safety standards, report concludes

In a report  presented by director general Rafael Mariano Grossi to Japanese prime minister Fumio Kishida in Tokyo yesterday, July 4, 2023, the IAEA added that the discharges of the treated water would have a negligible radiological impact to people and the environment.

The Fukushima Daiichi nuclear power station was seriously damaged in 2011 by an earthquake and tsunami that devastated the site.

The new report is the outcome of nearly two years of work by an IAEA Task Force made up of specialists from the agency who were advised by nuclear safety experts from 11 countries.

“Based on its comprehensive assessment, the IAEA has concluded that the approach and activities to the discharge of ALPS [Advanced Liquid Processing System] treated water taken by Japan are consistent with relevant international safety standards,” Grossi said in a foreword of the report. “Furthermore, the IAEA notes the controlled, gradual discharges of the treated water to the sea, as currently planned and assessed by TEPCO [Tokyo Electric Power Company], would have a negligible radiological impact on people and the environment.”

According to IAEA, 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 which are stored on site in High Integrity Containers. After going through the ALPS process, the water is then stored in tanks on site with the capacity to store 1,000m³ each.

After taking the decision in April 2021 to discharge the water stored at the Fukushima Daiichi nuclear power station (FDNPS) into the sea, Japan requested the IAEA to conduct a detailed review of the safety related aspects of plan. Japan’s Nuclear Regulation Authority (NRA) approved the plan in May.

The water stored at the FDNPS has been treated through ALPS to remove almost all radioactivity, aside from tritium. Before discharging, Japan will dilute the water to bring the tritium to below regulatory standards.

The IAEA’s review addressed all key safety elements of the water discharge plan in three major components, namely assessment of protection and safety; regulatory activities and processes; and independent sampling, data corroboration, and analysis.

Over the past two years, the Task Force has conducted five review missions to Japan, published six technical reports, and met with the Japanese government and TEPCO, the FDNPS operator, and analysed hundreds of pages of technical and regulatory documentation. Task Force members have also visited the site in eastern Japan to review discharge preparations there.  

The IAEA‘s safety review will continue during the discharge phase. The Agency will also have a continuous on-site presence and provide live online monitoring on its website from the discharge facility.  

Commenting on the risk posed by discharging the water, Dr Mark Foreman, Associate Professor of Nuclear Chemistry/ Industrial Materials Recycling, Chalmers University of Technology, Sweden, said: “The projected radiation dose to members of the public from the discharge of the ALPs treated water is in the range of 0.002 to 0.030 microSv per year.  The limit for the general public for occupational radiation exposure is 1000 microSv per year.  Thus the projected dose to the general public will be very low.”

“The concentration of tritium, the remaining radionuclide in the water to be discharged, is very low and well below levels of any environmental concern,” said Prof Robin Grimes, Steele Chair of Energy Materials, Imperial College London.  “The state of the tritium is important – in this case it is a component of water molecules [tritiated water] but not bound to more complex compounds.  There is no established mechanism for tritiated water bioaccumulation, so discharge will further dilute these low levels of tritium enormously.”