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CNA Explains: Why is Japan releasing Fukushima wastewater into the Pacific and how safe is it?

SINGAPORE: More than a decade after the devastating 2011 Tohoku earthquake and tsunami, Japan is set to release over a million tonnes of treated wastewater from its destroyed Fukushima Daiichi nuclear power plant into the Pacific Ocean.

The process will start on Aug 24, the Japanese government announced on Tuesday (Aug 22), and is expected to take decades to complete.

This comes more than a month after the plan was approved by the International Atomic Energy Agency (IAEA) on Jul 4.

CNA takes a look at how the wastewater will be treated and how safe it will be.

WHY IS JAPAN RELEASING NUCLEAR WASTEWATER INTO THE OCEAN?

Three reactors at the Fukushima Daiichi plant melted as a result of the 9.1-magnitude earthquake that struck in March 2011.

Nearly US$150 billion has been spent to clean up the worst atomic accident since the 1986 Chernobyl disaster.

However, the plant still produces 100 cubic metres of wastewater daily. A mixture of groundwater and seawater is used to keep the reactors cool, before being filtered and stored in tanks.

There are 1,000 tanks on site but space is running out, and they will reach their capacity of 1.3 million cubic metres in early 2024. 

Japan announced in April 2021 that it planned to gradually release the treated wastewater that has been accumulating at the plant since the disaster.

According to various media outlets, Japanese officials noted that the wastewater must be removed to avoid accidental leaks in the event of another earthquake as well as to create space for the decommissioning of the plant. 

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Plant operator Tokyo Electric Power Company (TEPCO) is also unable to continue clearing space for additional tanks, Bloomberg reported, adding that the utility company already felled 500 sq m of trees to make room for the tanks. 

In a 2020 report, TEPCO said it would discharge the water into the ocean over the course of 30 to 40 years.

HOW HAS THE WASTEWATER BEEN TREATED?

According to the IAEA, the tainted water has been recycled through the Advanced Liquid Processing System (ALPS), a pumping and filtration system which uses “a series of chemical reactions to remove 62 radionuclides from contaminated water”.

While most of the radioactive elements have been filtered out, it still contains tritium, an isotope that is difficult to separate from water due to it being chemically similar to hydrogen.

Tritium may “present a radiation hazard if inhaled or ingested but is only harmful to humans in very large doses”, according to IAEA. 

A TEPCO spokesperson told National Geographic that the wastewater will be repeatedly purified, sampled, and retested to confirm that the concentrations of radioactive substances fall below regulatory standards before being released. 

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IS THE TREATED WATER SAFE?

Over the past two years, IAEA’s task force has conducted five review missions and published six reports on the safety aspects of Japan’s plan to release the wastewater.

In the UN agency’s final review on Tuesday, it noted that Japan’s plan is “consistent with relevant international safety standards”.

It added that the “controlled, gradual discharges of the treated water to the sea … would have a negligible radiological impact on people and the environment”.

Even though tritium has a radioactive half-life of 12.32 years, the wastewater has a short biological half-life of seven days to 14 days in the human body, according to the IAEA.

“The biological half-life of a chemical (for example, a drug) in a living organism is the time it takes for half of that chemical to be depleted or eliminated from the body,” it added.

Experts said what Japan plans to do is consistent with that in other nuclear sites around the world.

“The controlled discharge of wastewater with small amounts of radioactive tritium happens regularly at nuclear sites all over the world,” Professor Jim Smith, an environmental scientist at the University of Portsmouth, told Science Media Centre.

IAEA expert Professor Mikhail Balonov shared the same sentiments, adding that nuclear facilities in other countries release more tritium in their wastewater each year, in comparison to the level of tritium in the wastewater that Japan intends to release. 

Online media collective The Conversation reported that about 8.4kg of tritium is already present in the Pacific Ocean, which is small in comparison to the total amount in Fukushima’s wastewater at 3g.

Prof Smith said: “Claims have been made about significant risks to the Pacific Ocean ecosystem from the planned Fukushima release. But these are not founded on scientific evidence. Tritiated water can damage DNA if ingested, but it is very weakly radiotoxic and does not biomagnify in the food chain so risks are extremely low.”

However, Associate Professor Kumpei Hayashi at Fukushima University told The Associated Press that the level of tritium is “still worrisome when it comes to the ageing problems that will emerge in 20 years or 30 years”. 

The American Association for the Advancement of Science also reported that more dangerous isotopes with longer radioactive lifespans – ruthenium, cobalt, strontium, and plutonium – can slip through the ALPS process at times. TEPCO noted that the isotopes are present in 71 per cent of the tanks on site.

“These radioactive isotopes behave differently than tritium in the ocean and are more readily incorporated into marine biota or seafloor sediments,” marine chemist Ken Buesseler told the association.

WHO IS MONITORING SAFETY STANDARDS?

The IAEA on Tuesday said that it will continue its safety review during the discharge of wastewater, while maintaining an on-site presence and providing “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,” said IAEA chief Rafael Grossi during a visit to Japan.

The agency’s task force, comprising 11 experts from the likes of Australia, Canada, France and the United Kingdom, will also “serve as the primary source for the technical and regulatory expertise needed to complete the IAEA’s review”.

Grossi 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.”

IAEA also said it would carry on with regular reporting to keep the public and other countries informed of the latest developments.

HOW IS THE WORLD REACTING?

Japan’s plan to gradually release the treated wastewater – enough to fill 500 Olympic-sized swimming pools – has been met with protests from fishing communities in Fukushima, who are worried that customers will shun their catches, despite strict testing protocols for food from the region.

Although TEPCO has been engaging with the communities and other stakeholders, fishing unions in Fukushima have urged the Japanese government for years not to release the water, arguing it would undo work to restore the damaged reputation of their fisheries.

A petition from the regions around the plant has garnered more than 250,000 signatures since the proposal was first made.

After Japan announced a date from which it will release the water, Hong Kong said it will curb some Japan food imports.

“The Japanese government has decided on its own to discharge nuclear wastewater into the sea,” Hong Kong leader John Lee said in a Facebook post.

“I express my strong objections,” he added, calling the move “irresponsible” as it disregarded food safety and environmental risks.

Hong Kong is the second-largest receiver of Japanese food imports, after mainland China, according to Japan’s ministry of agriculture.

The announcement followed a similar one by China’s General Administration of Customs, which had threatened a blanket ban on all foodstuffs from the areas.

The 10 prefectures named were Tokyo, Fukushima, Chiba, Tochigi, Ibaraki, Gunma, Miyagi, Niigata, Nagano and Saitama.

Through its embassy in Japan, Beijing said in July that the IAEA report cannot be a “pass” for the water release and called for the plan’s suspension.

Chinese Foreign Ministry spokesman Wang Wenbin also warned that the proposed release carries risks for neighbouring countries and Pacific Island nations, with Bloomberg quoting him as saying that the ocean is “not Japan’s private sewer”.

Some South Koreans were reported to be panic-buying salt due to contamination fears once the treated wastewater is released.

The rush to stock up on salt contributed to a nearly 27 per cent rise in the price of the commodity – compared with two months ago – in South Korea in June, though officials said the weather and lower production were also to blame.

The Pacific Islands Forum, consisting of 18 nations including Fiji and Australia, have also urged Japan to “consider alternatives and called for additional discussions on the risks”.

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