Fukushima japan
This aerial view shows the tanks containing treated radioactive wastewater at the Fukushima Daiichi nuclear power plant in Fukushima, northern Japan, on Aug. 22, 2023. Image Credit: AP

Japan began releasing wastewater from the crippled Fukushima nuclear plant into the Pacific Ocean on Thursday, a first step in decommissioning the dangerous site 12 years after one of the world’s worst nuclear accidents.

The discharge of water prompted a furious China to ban all seafood imports from its neighbour.

The water was distilled after being contaminated from contact with fuel rods at the reactor, destroyed in a 2011 earthquake and tsunami.

Tanks on the site hold about 1.3 million tonnes of the water - enough to fill 500 Olympic-sized swimming pools.

Japan has repeatedly insisted the wastewater will be harmless, with its position backed by UN atomic watchdog the International Atomic Energy Agency.

But China has warned it will contaminate the ocean, and immediately responded Thursday by blasting Japan as “extremely selfish”.

China then banned all Japanese seafood imports “to comprehensively prevent the food safety risks of radioactive contamination”.

What is Japan’s water release plan?

The utility responsible for the plant, Tokyo Electric Power (Tepco), has been filtering the contaminated water to remove isotopes, leaving only tritium, a radioactive isotope of hydrogen that is hard to separate. Tepco will dilute the water until tritium levels fall below regulatory limits before pumping it into the sea from the site on the coast north of Tokyo.

Water containing tritium is routinely released from nuclear plants around the world, and regulatory authorities support dealing with the Fukushima water in this way.

Tritium is considered to be relatively harmless because its radiation is not energetic enough to penetrate human skin. When ingested at levels above those in the released water it can raise cancer risks, a Scientific American article said in 2014.

The water disposal will take decades to complete alongside the planned decommissioning of the plant.

Is the water safe?

Japan and scientific organisations say the water is safe, but environmental activists argue that all possible impacts have not been studied. Japan says it needs to start releasing the water as storage tanks are full.

The International Atomic Energy Agency (IAEA), the UN nuclear watchdog, gave the plan a green light in July, saying it met international standards and the impact on people and the environment would be “negligible”.

Fukushima japan water nuclear
This aerial picture shows TEPCO's crippled Fukushima Daiichi Nuclear Power Plant in Okuma, Fukushima prefecture on August 24, 2023. Image Credit: AFP

Greenpeace said on Tuesday that the radiological risks have not been fully assessed, and the biological impacts of tritium, carbon-14, strontium-90 and iodine-129 - to be released with the water - “have been ignored”.

The filtering process will remove strontium-90 and iodine-129, and the concentration of carbon-14 in the contaminated water is far lower than its regulatory standard for discharge, according to Tepco and the government.

Japan said tritium levels in the water will be below those considered safe for drinking under World Health Organization standards.

The government said in a document it would take “appropriate measures, including immediate suspension of the discharge” if unusually high concentrations of radioactive materials were detected.

The South Korean government has concluded from its own study that the water release meets international standards and said it respected the IAEA assessment.

What was the Fukushima disaster?

On March 11, 2011, a magnitude 9.0 quake hit off the coast of northeast Japan, triggering a tsunami that devastated towns and villages and sparked the world’s worst nuclear accident since Chernobyl.

The tsunami swamped backup power and cooling systems at the Fukushima plant, eventually causing meltdowns at three of six reactors. More than 160,000 people were eventually evacuated from the area.

A commission appointed by parliament later concluded that Fukushima was a “profoundly man-made disaster” that could have been prevented, and mitigated by a more effective response.

What has the reaction been like?

Tepco has been engaging with fishing communities and other concerned groups and is promoting agriculture, fishery and forest products to reduce any reputational harm to produce from the area.

fukushima korea
Police officers stand guard outside of a building which houses Japanese Embassy, in Seoul, South Korea, Thursday, Aug. 24, 2023. Image Credit: AP

Fishing unions in Fukushima have urged the government for years not to release the water, arguing it would undo work to restore the damaged reputation of their fisheries.

Masanobu Sakamoto, the head of the National Federation of Fisheries Cooperative Associations, said on Monday the group understood the release could be scientifically safe but still feared reputational damage.

South Korean Prime Minister Han Duck-soo said Thursday that there was “no need to be excessively concerned” about the plan.

Han also criticised what he called a “politically driven” campaign and “fake news” to fan fears.

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A vendor retrieves a lobster at a wholesale fish market in Beijing on August 24, 2023. China on August 24 banned all Japanese seafood imports over what it said was the "selfish" release of wastewater from the crippled Fukushima nuclear plant. Image Credit: AFP

How has China reacted?

China is the biggest importer of Japanese seafood and has been the most vocal, calling Japan’s plan irresponsible, unpopular and unilateral.

Shortly after the 2011 tsunami and earthquake damaged the Fukushima plant, China banned imports of food and agricultural products from five Japanese prefectures. China later widened its ban to 10 of Japan’s 47 prefectures.

The latest import restrictions were imposed in July after the IAEA approved Japan’s plans to discharge the treated water.

- With inputs from Reuters, AFP