An International Atomic Energy Agency (IAEA) safety review has concluded that Japan’s plans to release treated water stored at the Fukushima Daiichi nuclear power station (FDNPS) into the sea are consistent with IAEA safety standards. In a report formally presented by Director General Rafael Mariano Grossi to Japanese Prime Minister Fumio Kishida during his recent visit to Tokyo the IAEA also said discharges of the treated water would have a negligible radiological impact on people or the environment.
The report is the result of investigations over almost two years by an IAEA Task Force comprising top specialists from within the Agency advised by internationally recognised nuclear safety experts. The Task Force is chaired by a senior IAEA official and includes experts from the IAEA Secretariat alongside internationally recognised independent experts with extensive experience from a wide range of technical specialties from Argentina, Australia, Canada, China, France, the Marshall Islands, South Korea, Russia, the UK, the USA and Viet Nam. They reviewed Japan’s plans against IAEA Safety Standards which serve as a global reference for protecting people and the environment and contribute to a harmonised high level of safety worldwide.
NRA approved the plan to release treated water stored at the Fukushima Daiichi NPP in July 2022. The water, used to cool the melted reactor cores in the aftermath of the 2011 nuclear disaster, is stored in around 1,000 huge tanks at the plant containing more than 1.3m tonnes. Total storage capacity has been reached and NRA has deemed it safe to release the water following treatment although it will still contain traces of tritium.
The contaminated cooling water and groundwater is treated by the Advanced Liquid Processing System (ALPS), which removes most of the radioactive contamination, with the exception of tritium. The government therefore plans to dilute the treated water so that tritium levels fall below national regulations before releasing it. Japan initially announced plans to discharge treated water into the sea over a period of about 30 years in April 2021, asking the IAEA to review these plans. Japan’s Nuclear Regulation Authority (NRA) undertook a final safety inspection a day after plant operator Tokyo Electric Power Company Holdings (Tepco) installed the last equipment needed for the release – the outlet of the undersea tunnel constructed to release the water 1 kilometre offshore.
“Based on its comprehensive assessment, the IAEA has concluded that the approach and activities to the discharge of ALPS 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, would have a negligible radiological impact on people and the environment.”
IAEA confirmed that the water stored at the FDNPS has been treated through the ALPS facility 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: 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 many times with the Japanese government and Tepco. It has also analysed hundreds of pages of technical and regulatory documentation. Task Force members have several times visited the site to review discharge preparations there.
Director General Grossi said the report issued today “represent a significant milestone in the IAEA’s review” but that “our task is only just beginning”. He added: “The IAEA will continue to provide transparency to the international community making it possible for all stakeholders to rely on verified fact and science to inform their understanding of this matter throughout the process,” he said.
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. “This will ensure the relevant international safety standards continue to be applied throughout the decades-long process laid out by the government of Japan and Tepco,” Grossi said.
IAEA says it recognises that the release plan raises societal, political and environmental concerns. In May, the Agency published a report detailing the results of the first interlaboratory comparison conducted for the determination of radionuclides in samples of ALPS treated water. IAEA says these findings “provide confidence in Tepco’s capability for undertaking accurate and precise measurements related to the discharge of ALPS treated water”. It adds: “Tepco has demonstrated that it has a sustainable and robust analytical system in place to support the ongoing technical needs at FDNPS during the discharge of ALPS treated water.”
After presenting the 140-page report to Prime Minister Kishida, Grossi visited the site and held two press conferences. He plans to visit China, South Korea and the Pacific islands to address their concerns about the planned water release. “There are questions and it is my responsibility to answer questions,” he said, adding:” We will always be available.”
Grossi emphasised: “Our work here is not yet over… Assessing a plan is not enough. My experts will come back to Fukushima repeatedly, and for as long as the process takes, to take samples at different locations and to confirm that the water remains safe. A clean ocean matters to us all.”
Image: Tanks of contaminated water at the Fukushima Daiichi site (courtesy of IAEA)