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Numerous tanks currently store contaminated water at the Fukushima nuclear power plant. (Yonhap News)

What effects will Korea face when Japan releases contaminated water from the Fukushima nuclear power plant into the ocean?

The ocean release’s impact on Korea is drawing renewed attention after Japan’s Nuclear Regulation Authority (NRA) approved the Tokyo Electric Power Company (TEPCO) plan on Friday, which raises the likelihood that the plan will be put into motion next spring.

On Friday, the NRA granted official approval to an implementation plan submitted by TEPCO last December for the design and operation of facilities for the ocean release of contaminated water.

According to reports in the Japanese press, the NRA carried out a process of gathering resident opinions after the implementation plan’s authorization in May. On July 22, it concluded its approval procedures, having determined that the plan presented “no safety issues.”

As of July 14, some 1,060 storage tanks on the Fukushima Daiichi nuclear power plant site that had been put in place through late 2020 were storing a total of 1,307,811 cubic meters of contaminated water containing various radioactive substances.

The contents include cooling water introduced to cool off nuclear fuel that was continuing to generate heat due to the fusion in the wake of the 2011 disaster, along with rainwater and groundwater that had entered the plant. The water has been treated with an advanced liquid processing system (ALPS) for radionuclide removal.

While the rate of increase in contaminated water has been slowing, an average of 130 cubic meters per day was still produced last year. At this rate, it is only a matter of time before the storage tanks’ capacity of 1.37 million cubic meters is reached.

TEPCO’s plan is to have the water ruled “treated” when it has purified to the point where it does not exceed discharge thresholds for 62 forms of radioactive material (not including tritium), and to commence dumping it into the ocean in spring 2023.

The problem with this approach has to do with the tritium, which cannot be removed through the ALPS process.

As for the unremoved tritium, TEPCO plans to release the water after using seawater to dilute its concentration down to below one-fortieth of the threshold for discharge. This approach does not actually change the amount of tritium in the seawater.

The total radioactivity of tritium within the contaminated water is estimated at around 860 trillion becquerels.

That’s over quadruple the amount of tritium released annually by all of Korea’s nuclear power plants combined. Tritium, which became a source of controversy in Korea last year due to a leak at the Wolsong nuclear power plant, reportedly causes internal radiation exposure when it enters the human body through contaminated seafood and is converted into organically bound tritium.

The South Korean government has not provided answers as to what sort of impact the radioactive substances in the contaminated water that Japan releases will have on its neighbors to the west.

After a meeting of relevant government agencies on Friday, the administration said that the Korea Atomic Energy Research Institute and Korea Institute of Ocean Science and Technology were at work “improving [analytical] models to boost simulation accuracy,” adding that Seoul planned to “use bilateral communication and discussion channels with Japan to continue urging it to provide sufficient information for a safety examination and adopt a responsible reaction for the safe processing of contaminated water from the nuclear power plant.”

This response amounts to an admission not only that the South Korean government is not receiving the necessary information from Japan to analyze the impact of an ocean release scenario, but also that it does not have a perfected simulation model for the spreading of radioactive material in the ocean that it could use to analyze the information that is provided.

Commenting on the delay in analyzing the impact of the release of water from Fukushima, a Ministry of Oceans and Fisheries official said, “Currently, we are capable of performing simulation analyses, but we haven’t been doing so because of problems with poor model accuracy.”

“When we do announce analysis results to the international community, we want to do so after we’ve boosted the model’s accuracy to a level where a response is logically possible,” the official explained.

A Ministry of Science and ICT official said, “The improvements to the model are taking place according to the original schedule.”

“Once they are completed as planned, we may have the first analysis results within the year,” they predicted.

By Kim Jeong-su, senior staff writer

Please direct questions or comments to [english@hani.co.kr]