A deal has been reached with the International Atomic Energy Agency (IAEA) for a monitoring regime for the highly contentious discharge of treated waste water from Japan’s Fukushima nuclear plant.

The deal struck between the IAEA and Japan sets out the full scope for what is claimed will be a comprehensive and continuous safety review of the discharge of treated water from the Fukushima Daiichi Nuclear Power Station (FDNPS).

Both parties claimed this will now pavie the way for decades of independent monitoring, sampling and analysis at the site and at sea.

IAEA Director General Rafael Mariano Grossi and Japanese Foreign Minister Kamikawa Yoko signed the Memorandum of Cooperation on the side-lines of the United Nations General Assembly in New York, nearly four weeks after the discharge of the water treated through the Advanced Liquid Processing System (ALPS) began.

The IAEA has been reviewing the safety of Japan’s plan on how to handle the treated water since it was first announced in 2021 and today’s agreement focuses on the Agency’s long-term activities during the discharge itself.

 “[The] agreement sets the broad parameters for the IAEA’s permanent presence at the site to implement the monitoring, corroboration and assessment activities that are indispensable for transparency and for building confidence – both in Japan and abroad – that the discharge will neither harm people nor the environment,” IAEA director general Grossi said.

“We will stay and carry out our technical work until the last drop of the treated water has been safely discharged into the sea,” he said. “Through its independent and scientific work, the IAEA will be able to provide assurances to people around the world that the discharge will cause no harm.”

On 24 August Tokyo Electric Power Company (TEPCO) – Fukushima Daiichi’s operator – on 24 August started discharging the ALPS treated water stored at the site. To bring the tritium levels below operational limits, the water is also diluted before it is discharged.

The IAEA’s two year detailed safety review of Japan’s plan had previously concluded  that the approach and activities for the discharge are consistent with relevant international safety standards and would have a negligible radiological impact on people and the environment.

Earlier this month, the IAEA’s first independent sampling and analysis of seawater near FDNPS since the discharge started also confirmed that the tritium levels were below Japan’s operational limits.