Waste Management

Fukushima-Daiichi / IAEA Calls For More Details On Independent Monitoring Of Water Discharge

By David Dalton
17 June 2022

Task force highlights need for ‘robust and transparent system’
IAEA Calls For More Details On Independent Monitoring Of Water Discharge
Water storage tanks at the Fukushima-Daiichi nuclear power station site. IAEA/Dean Calma.
An International Atomic Energy Agency task force established to review the discharge of treated water from the destroyed Fukushima-Daiichi nuclear power station has called for more information about Japan’s plans for independent monitoring of the project.

The task force has released a report setting out its initial observations of regulatory aspects of the proposed advanced liquid processing system, known as Alps, which will be use for the discharge of treated water.

The task force said it recognised that some aspects of independent monitoring by the regulatory body, the Nuclear Regulation Authority (NRA), are clearly present in the plans, including the monitoring of the same sample locations by different organisations, including Fukushima-Daiichi owner Tokyo Electric Power Company (Tepco), the NRA and the contracting of accredited commercial laboratories by the NRA.

“However, more information on the methodology used for independent monitoring could aid the task force’s understanding,” the report said. “In particular, the task force would welcome a more detailed description of how the results of Tepco’s monitoring will be assessed and compared against those from the organisations independent of Tepco and how any discrepancies or inconsistencies will be resolved.

“For example, the NRA may want to consider defining criteria for confirmatory analyses, taking into consideration measurement uncertainties.”

The task force highlighted that a robust and transparent system for independently verifying Tepco’s monitoring results will provide reassurance to interested parties of the independence of Japan’s comprehensive radiation monitoring plan.

The review of regulatory aspects is one component of the task force’s three-pronged review, to be carried out before, during and after the discharge of treated water. The other two components are the review of technical aspects related to safety of the proposed discharge of Alps treated water – with the first report on this topic released in April this year – and conducting independent sampling and analysis.

The report covers the findings from a task force mission to Japan held from 21 to 25 March.

Tepco Plans ‘Batch Discharges’ Over 30 Years

The current approach for water discharge is to conduct a series of controlled discharges of Alps treated water into the sea – so-called “batch discharges” – over a period of approximately 30 years. The IAEA said the details of this proposed approach are under regulatory review by the NRA and could change.

Last month the NRA granted initial approval for Tepco’s plan to release water from Fukushima-Daiichi into the sea, saying there are no safety issues.

In April 2021 Japan announced its policy to gradually discharge more than 1.25 million cubic metres of treated water into the sea, subject to approval from the NRA.

It asked for the International Atomic Energy Agency’s assistance to help ensure the project’s implementation. Japanese authorities said there was no practical alternative to releasing the water as storage space ran out. They said there was no risk to human health and that operating nuclear plants around the world release similar water every day.

In part used to cool melted nuclear fuel at Fukushima-Daiichi, which has been shut down since a March 2011 earthquake and tsunami, the water has been treated through a filtration process known as advanced liquid processing system Alps to reduce the radioactivity before being stored in tanks.

Space for the tanks is running out and the long-term management of the treated water is necessary to allow for the further decommissioning of the Fukushima-Daiichi station.

Five disposal methods for the water were being considered by the government: controlled discharge into the sea, ground injection, discharge as steam, discharge as hydrogen, and solidification for underground burial.

Japan intends to release the water with levels of tritium – the only radionuclide that cannot be removed through this treatment – well below national regulatory limits and World Health Organisation standards for drinking water.

The IAEA said in an earlier report that Japan had made significant progress as it prepares to discharge the treated water from Fukushima-Daiichi.

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