Japan to release treated Fukushima wastewater into sea, IAEA monitoring safety aspects


The Japanese government said last week it will release more than a million tonnes of wastewater into the Pacific Ocean from the Fukushima nuclear power plant (NPP) that was crippled by a tsunami in 2011.  

Under the plan, the wastewater, which contains hard-to-remove radioactive tritium because of being used to cool down melted nuclear fuel at the damaged plant, will be discharged through an underwater tunnel into the Pacific Ocean after being treated. 

The schedule of the plan was confirmed during a meeting of Japan’s cabinet ministers at the Prime Minister’s office. 

“We expect the timing of the release would be sometime during this spring or summer,” chief cabinet secretary Hirokazu Matsuno told mediapersons following the cabinet meeting, adding that the government will wait for a comprehensive report from the International Atomic Energy Agency (IAEA) before the release. 

The operator of the Fukushima NPP, Tokyo Electric Power Company (TEPCO), has said that after treatment the levels of most radioactive particles meet the national standards. Japan says that the release of the wastewater is safe as it is processed to remove almost all radioactive elements and will be greatly diluted. 

The contaminated water produced daily and being stored in tanks at the plant is expected to soon reach capacity, and the lengthy process of dumping the radioactive water into the ocean is projected to take several decades. 

According to the IAEA, tritium is very difficult to remove from water and is only harmful to humans in large doses. 

The IAEA says the Japanese plan is safe and that the release is similar to the disposal of wastewater at other plants around the world. Some of Japan’s neighbouring countries have, however, voiced concern.  

“Releasing into the ocean is done elsewhere. It’s not something new. There is no scandal here”, IAEA Director General Rafael Mariano Grossi said in 2021. 

The IAEA said last month that its Task Force established to review the safety of Japan’s plans to discharge the Advanced Liquid Processing System (ALPS)-treated water stored at the Fukushima NPP into the sea has released its third report on December 29, 2022.  

The new report sets out how the IAEA is conducting its own independent checks of key data related to the monitoring of the safety of the treated water before, during and after its discharge. 

“This corroboration work is one of the three components in the Task Force’s review of Japan’s plans to ensure they are in line with IAEA Safety Standards. The review also comprises assessments of the technical plans and of regulatory activities and processes related to the water discharge”, an IAEA release said.  

The new report summarizes the main elements of the IAEA’s corroboration activities and explains the methodologies to be used. It also provides an update on the progress made to date in this work, and what future activities can be anticipated. 

Fukushima NPP operator Tokyo Electric Power Company is required to determine the characteristics and activity of the ALPS treated water to be discharged into the sea. This characterization is used as a basis to establish and implement effective monitoring programmes to ensure that any public exposure due to the discharges is adequately considered, IAEA said.  

The report released on December 29, 2022 focuses on how the IAEA will conduct its own independent checks of the radiological contents of the water stored in the tanks and how it will analyse environmental samples (for example, seawater and fish) from the surrounding environment. 

This corroboration of data will be conducted using interlaboratory comparisons involving both IAEA laboratories as well as independent third-party laboratories from France, South Korea, Switzerland, and the United States – all of which are members of the network of Analytical Laboratories for the Measurement of Environmental Radioactivity (ALMERA). 

Additionally, the report covers how the IAEA will independently review Japanese capabilities for measuring the radiation exposure of workers at the nuclear power plant. 

“This independent work will build confidence in the accuracy of data provided by TEPCO and the Japanese authorities and will give another layer of assurance that they are adhering to relevant IAEA Safety Standards,” IAEA’s Department of Nuclear Safety Director and Chair of the Task Force, Gustavo Caruso, said in a statement.  

The report includes details on the first collections of treated water samples from the tanks, as well as environmental samples, taken in 2022.  

The initial results of the IAEA’s corroboration activities will be made available in 2023 before the planned discharges of the ALPS treated water begin, the statement said. 

Subsequent results will be included in future reports that will provide the details of the technical evaluation as well as information for the public on how to read and interpret the data, it added.