Japan started the release of the Fukushima nuclear-contaminated water into the Pacific Ocean at 1p.m. on Thursday.

The release began more than 12 years after the meltdowns of three reactors at the Fukushima Daiichi nuclear power plant that was heavily damaged by the massive earthquake and tsunami that struck Japan's northeastern coast on March 11, 2011. Radioactive water - both seeping groundwater and water used to cool the reactors - has accumulated at the site ever since. The company in charge of running the power plant - the Tokyo Electric Power Company (TEPCO) - and the government say the mass quantities of the water have hampered the daunting task of removing the deadly toxic melted debris from the reactors.

Final preparation began Tuesday when just one ton of treated water was sent from one of the site's many storage tanks to be diluted with 1,200 tonnes of seawater, and the mixture was kept in the primary pool for two days for final sampling, said TEPCO executive Junichi Matsumoto.

A batch of 460 tonnes will be sent to the mixing pool Thursday for the actual discharge. The tritium levels from those samples were significantly safer than the legally releasable levels, Matsumoto said.

The discharge plan

The water that is being released now is in smaller portions initially and with extra checks, with the first discharge totaling 7,800 cubic meters over about 17 days starting Thursday, according to TEPCO. The water will enter an undersea tunnel and be released a few minutes later from a point one kilometer off the coast.

That water will contain about 190 becquerels of tritium per liter, below the World Health Organization drinking water limit of 10,000 becquerels per liter, according to TEPCO. A becquerel is a unit of radioactivity. 

The company aims to release 31,200 tonnes of the treated water by the end of March 2024, which would empty only 10 tanks at the site. The pace will pick up later. 

The operator built over 1,000 steel tanks on the site with a capacity of about 1.37 million cubic meters. As of August 3, 2023, over 1.34 million cubic meters of nuclear wastewater are currently stored in the tanks, which is 98 percent of the total capacity, according to TEPCO.

Under TEPCO's plan, it would take up to 30 years or even longer for wastewater to be released into the ocean.

Fukushima nuclear contaminated-water vs. normal nuclear wastewater

Nuclear-contaminated water from the Fukushima Daiichi nuclear power plant has fundamental differences from the discharge of a normally operated nuclear plant, either in terms of the original source, category of radionuclides, or disposal treatment, said Wang Wenbin, a Chinese Foreign Ministry spokesperson, in July. 

The release of coolant water (after treatment) is routine for nuclear plants all over the world. But because water at Fukushima was poured directly onto the melting reactors, instead of being circulated around them, it became loaded with a much higher-than-usual concentration of radioactive compounds, called radionuclides.

Many scientists around the world have a consensus that the Fukushima nuclear contaminated-water contains up to 64 kinds of nuclear radioactive elements, and more than 70 percent exceed the standards, according to Gao Zhiguo, president of the Chinese Society of the Law of the Sea.

Concerns raised around the globe

The Japanese government's insistence on releasing the contaminated water into the ocean has raised worries and opposition both at home and on the world stage.

Japanese fisheries groups worry the release will cause further damage to the reputation of their seafood. Fukushima Prefecture's current catch is only about one-fifth its pre-disaster level due to a decline in the fishing population and smaller catch sizes.

The head of the National Federation of Fisheries Cooperatives, Masanobu Sakamoto, said on Monday that "scientific safety and the sense of safety are different."

Also, citizens from Fukushima and other prefectures announced Wednesday that they will take the Japanese government and TEPCO to court to stop the nuclear-contaminated water discharge plan.

Plaintiffs from the prefectures of Fukushima, Miyagi and Ibaraki will formally file a lawsuit on September 8 at the Fukushima District Court, according to Japan's news agency Kyodo.

This will be the first lawsuit in Japan where citizens demand the cancellation of the plan to discharge nuclear-contaminated water from the crippled Fukushima Daiichi Nuclear Power Plant into the sea.

Lee Jae-myung, chief of South Korea's main opposition Democratic Party, on Wednesday called Japan's decision an "act of terror."

"Japan, which threatened the right to life of neighboring countries in the past with the imperialist war of aggression, is about to bring another irreversible disaster to South Korea and countries around the Pacific Ocean by discharging nuclear-contaminated wastewater," Lee said during a party meeting.

China's Hong Kong Special Administrative Region (HKSAR) said on Tuesday that it would ban certain aquatic products from Japan starting Thursday following Tokyo's announcement of nuclear-contaminated water discharge.

(With input from agencies)

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