The International Atomic Energy Agency on Tuesday provided reassurance on the safety of Japan's plan to release treated radioactive water from the disaster-hit Fukushima nuclear plant into the sea, a significant step forward for Tokyo as it pushes ahead with the move despite concerns from China and other neighboring countries.

In a report submitted by IAEA chief Rafael Grossi to Prime Minister Fumio Kishida in Tokyo, the U.N. nuclear watchdog concluded that Japan's water discharge plan is "consistent" with international safety standards and would have "a negligible radiological impact on people and the environment."

International Atomic Energy Agency Director General Rafael Grossi (L) and Japanese Prime Minister Fumio Kishida are pictured at the premier's office in Tokyo on July 4, 2023. Grossi submitted the agency's safety review on releasing treated radioactive water from the crippled Fukushima nuclear power plant into the Pacific Ocean. (Kyodo)

During their meeting, the IAEA director general called its two-year review "dedicated, scientific" and "impartial," telling Kishida that the results "have all the elements" necessary for Japan to "move on to the next phase."

Kishida said Japan will respond "sincerely" to the review and will continue to explain its plan to affected residents and the international community "with a high level of transparency."

"We will not allow a discharge that would be harmful to human health and the environment," the Japanese prime minister said.

The Japanese government plans to study the IAEA's assessment before making a definitive decision regarding the timing of starting the water release, which is aimed at "around the summer."

Grossi emphasized in the IAEA report that its document is neither a recommendation nor an endorsement of the water release, and the Japanese government has the final say on the issue while committing to continuing the safety review during what could become a 30-year discharge phase.

The government has been seeking support over the release of the treated water into the Pacific Ocean after announcing its basic policy to do so in 2021, but local fishermen have been worried about the potential for reputational damage while China has demanded a halt to the release.

The government has said that the disposal of treated water is necessary to decommission the crippled reactors of the Fukushima Daiichi nuclear power plant, devastated by a powerful earthquake and ensuing tsunami in March 2011.

Japanese Prime Minister Fumio Kishida (R) and International Atomic Energy Agency Director General Rafael Grossi hold talks at the premier's office in Tokyo on July 4, 2023. (Kyodo) ==Kyodo

Massive amounts of contaminated water have been generated in the process of cooling melted reactor fuel. The water has been kept in over 1,000 tanks installed at the site after going through the advanced liquid processing system that removes most radionuclides except tritium, but the containers are nearing capacity.

The water will be diluted with seawater to one-40th of the concentration permitted under Japanese safety standards before being released via an underwater tunnel 1 kilometer off the power plant.

Tritium is known to be less harmful to the human body than other radioactive materials, such as cesium and strontium, as it emits very weak radiation and does not accumulate or concentrate inside the body.

Nuclear power plants worldwide routinely release treated water containing low-level concentrations of tritium and other radionuclides into the environment as part of normal operations, according to the U.N. agency.

The IAEA agreed to conduct the review of Japan's water release policy in 2021 and has since addressed all key elements of the plan, including safety, regulatory activities and independent sampling of the water.

It has also said a review conducted by the country's regulation authority on the plan was appropriate.

Grossi reiterated in a press conference Tuesday that the IAEA will ensure the water discharge will be conducted safely, with the agency planning to establish an on-site presence to provide live online monitoring.

"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," he said, referring to the plant operator Tokyo Electric Power Company Holdings Inc.

In an earlier assessment, the IAEA said neither it nor third-party laboratories "detected any additional radionuclides at significant levels" from the treated water, adding that TEPCO's sample collection procedures and analytical methods were appropriate and fit for the purpose.

TEPCO said Tuesday it will use the IAEA's input to ensure the safety of the water release, and its related activities will continue to be under the agency's review in light of international safety standards.

The utility completed construction work of discharge facilities at the end of June, and the Nuclear Regulation Authority is expected to announce the results of its final inspection of the facilities before the discharge begins.

During his four-day stay in Japan that began Tuesday, Grossi will visit the Fukushima Daiichi plant and inaugurate an IAEA office at the site, according to the agency.

He will then travel to South Korea from Friday to Sunday, where he is expected to brief the government about the report.

The South Korean government has taken a cautious stance on Japan's plan to release the water amid public concerns about how the discharged water could affect people's health and the ocean environment.

But Seoul's stance may have softened recently as South Korea and Japan are seeing a thaw in their bilateral ties that had increasingly soured over wartime compensation and other issues.

The Chinese Foreign Ministry, meanwhile, was critical of the IAEA safety review, saying it "should not be the 'shield' or 'green light' for Japan's discharge of nuclear-contaminated water into the ocean," adding that the report "failed to fully reflect views from experts that participated in the review."

Gist of IAEA's safety review report on Fukushima water release plan

The following is the gist of the International Atomic Energy Agency's report released Tuesday on its safety review of Japan's plan to discharge treated radioactive water from the crippled Fukushima Daiichi nuclear power plant into the sea.

-- Water discharge plan is consistent with international safety standards.

-- Water discharge would have a negligible radiological impact on people and environment.

-- Water discharge is a national decision by the Japanese government and the IAEA report is neither a recommendation nor an endorsement of the policy.

-- IAEA will continue its safety review during the discharge phase, including by establishing an on-site presence, as part of efforts to provide transparency to the international community.

International Atomic Energy Agency Director General Rafael Grossi (L) holds talks with Japanese Foreign Minister Yoshimasa Hayashi at the Iikura Guest House in Tokyo on July 4, 2023. (Kyodo) ==Kyodo
Photo taken from the town of Futaba, Fukushima Prefecture, shows the crippled Fukushima Daiichi nuclear power plant on July 4, 2023. (Kyodo)

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