Japan will start releasing treated radioactive water from the crippled Fukushima nuclear power plant into the sea on Thursday, weather conditions permitting, Prime Minister Fumio Kishida said, despite concerns among local fishermen and persistent opposition from China.

The controversial decision was made at a ministerial meeting on Tuesday, as a significant amount of the water has accumulated at the site amid ongoing cleanup efforts following the 2011 nuclear accident triggered by a devastating earthquake and ensuing tsunami.

During the gathering at the prime minister's office, Kishida vowed to make the utmost effort to dispose of the treated water and decommission the wrecked plant in a safe manner, saying, "The government will take full responsibility, even if it takes decades."

Fishing boats moored at Ukedo fishing port in Namie, Fukushima Prefecture, are pictured on Aug. 22, 2023, with the crippled Fukushima Daiichi nuclear power plant seen in the background. (Kyodo)

Japan's national fisheries federation has maintained its opposition, reflecting concerns among fishermen who feel the plan is going ahead without their consent or sufficient explanation on whether the government can truly safeguard the reputation of their seafood products.

In the wake of Kishida's announcement, Tomoaki Kobayakawa, president of plant operator Tokyo Electric Power Company Holdings Inc., told reporters that he has instructed employees to "swiftly" begin preparations for the water discharge.

In what could be a process taking around 30 years, TEPCO plans to start the release "carefully and from a small amount," an official in charge of the processed water said later in the day.

It plans to confirm that the radiation level of the water is below the country's safety standard by taking a sample from the first batch of the liquid -- 7,800 tons -- that will be released into the Pacific Ocean from the Fukushima Daiichi nuclear complex. The results are expected to be released by Thursday.

In April 2021, Kishida's predecessor, Yoshihide Suga, gave his approval for the water release "in around two years." The current government said in January that it would carry out the plan sometime from "spring to around summer."

The International Atomic Energy Agency concluded in July that Japan's plan aligns with global safety standards and would have a "negligible radiological impact on people and the environment," prompting the government to proceed with the water discharge.

While several European countries have lifted restrictions on Japanese food imports, China has introduced blanket radiation testing on seafood products from its neighbor in an apparent bid to convince Tokyo to halt its plan, a source of diplomatic tension.

Following the announcement of the starting date of the discharge, China's Foreign Ministry spokesman Wang Wenbin said Beijing has "made serious demarches" to Tokyo over the issue and suggested it could implement additional measures to restrict Japanese seafood imports.

Hong Kong authorities on the same day announced that they will restrict seafood imports from 10 Japanese prefectures including Fukushima and Tokyo from Thursday.

For years, Beijing has expressed strong objections to the envisioned water discharge, refusing to use the pseudo-scientific term "treated" to downplay the risks of the "nuclear-contaminated water."

Natsuo Yamaguchi, who heads the junior ruling coalition partner of Kishida's Liberal Democratic Party, voiced willingness to explain the water discharge plan to the Chinese government when he visits the country next week.

In South Korea, the government has said it respects the outcome of the IAEA's review based on its own analysis of Japan's plan, The country's opposition parties, however, remain concerned about the negative effects of the water disposal.

Seoul regards there is no problem in the discharge plan but said Tuesday it will not endorse or support it in consideration of persisting concerns among the public, stressing it will continue to monitor whether the discharge will be carried out in accordance with the plan.

At home, local fishermen have been worried that the reputation of their seafood products could face further harm, arguing they have already endured years of arduous efforts to regain consumer trust after the initial nuclear crisis.

Considering such fears from the fishing community, the government has decided to discharge the treated water before the start of the trawl fishing season off Fukushima in September, sources close to the matter said.

Photo taken from a Kyodo News helicopter shows the Fukushima Daiichi nuclear power plant in Fukushima Prefecture on Aug. 22, 2023. (Kyodo) ==Kyodo

Photo taken from a Kyodo News helicopter on Aug. 22, 2023, shows tanks at the crippled Fukushima Daiichi nuclear power plant storing treated radioactive water from the plant in northeastern Japan. (Kyodo) ==Kyodo

In the last-minute effort to seek consent to the government's plan, Kishida spoke with the head of Japan's national fisheries federation on Monday at the premier's office a day after inspecting the Fukushima plant himself.

But the National Federation of Fisheries Cooperative Associations, under its head Masanobu Sakamoto, has not budged, saying that scientifically proven safety does not necessarily mean that the public will feel assured of the safety of seafood products.

At Monday's meeting, Kishida said he will keep trying to communicate with local fishermen to win their group's backing for his administration's efforts to ensure the safety of the water and for its measures to respond to potential reputational damage.

The government has set up two separate funds worth 30 billion yen ($206 million) and 50 billion yen, respectively, aimed at responding to any harmful rumors and supporting local fishermen in sustaining their businesses.

Since the nuclear disaster, the water has been kept in more than 1,000 tanks installed at the site after treated by an advanced liquid processing system, which is capable of removing most radionuclides except tritium.

The tanks, now containing about 1.34 million tons, are nearing their capacity and are expected to reach their limit as early as 2024 unless the operator initiates the release of the treated water.

The government and TEPCO have insisted that further increasing the number of tanks is difficult, and that releasing the accumulating water into the ocean is indispensable to carry on with the decommissioning work that requires storage and other facilities to be built on the site.

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

About 17 days will be spent to release the first batch of the wastewater, according to TEPCO.

In the current fiscal year through next March, a total of 31,200 tons are slated for discharge, equivalent to the storage capacity of 30 tanks. It will contain 5 trillion becquerels of tritium, about one-fourth of the annual maximum limit allowed.

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

But critics say it remains uncertain whether the radioactive material is definitely safe for humans and the environment, citing a lack of long-term data.

Photo taken in June 2023 shows a crane barge anchored near where treated radioactive water will be released in waters off the crippled Fukushima Daiichi nuclear power plant. (Kyodo) 

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