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Members of Greenpeace Korea protest Japan’s plan to release radioactively contaminated water into the ocean in front of the Japanese Embassy in Seoul in July 2020. (provided by Greenpeace)

The Japanese government’s decision to dump contaminated water from the Fukushima Daiichi Nuclear Power Plant into the ocean has critics contending that the ocean release approach could not be the best option.

When it comes to treating contaminated water, even the experts have trouble finding a clear alternative — but that does not mean there are no choices available. Some of the approaches that have been mentioned include storing the water until levels of radioactive material have sufficiently dropped or converting it for storage in solid form.

The Japanese government Tuesday decided to proceed with the ocean release plan, in which around 1.25 million tons of contaminated water currently being stored in tanks at the Fukushima Daiichi site are to be discharged into the ocean over 30 years.

It plans to remove radioactive material through an advanced liquid processing system (ALPS) before the release, with water used to dilute tritium concentrations to below the legally established threshold, it explained.

Environment groups and experts contended that the real best option would be long-term storage of the contaminated water. Due to the presence of radioactive materials like tritium that ALPS cannot filter out, they argue that the priority should be on minimizing toxicity by keeping the water stored through several half-lives, or the period needed for radiation levels to drop by half.

“Diluting the contaminated water with additional water only lowers the concentration of radioactive materials, not the intensity of radioactivity,” explained Lee Jeong-yoon, president of the Nuclear Power Safety and the Future.

“The half-life of tritium is 12 years. We need to go through several of these half-lives to reduce the intensity,” he said.

“We should release it after first storing it in water tanks for 50 to 120 years.”

Han Byeong-seop, director of the Institute for Nuclear Safety, said, “Once 100 years or so have passed, then we may be able to talk about the radiation having dropped to satisfactory levels. If that’s not possible, then a rational alternative would be to store it for at least 30 years before releasing it.”

In a report titled “The reality of the Fukushima radioactive water crisis” published in October 2020, Greenpeace Germany said it had “concluded that the only acceptable solution is continued long-term storage and processing of the contaminated water,” which would “[allow] the threat from radioactive tritium to diminish naturally.”

But from the Japanese government’s standpoint, long-term storage through additional water tanks not only raises cost issues but also stands to contribute to perceptions at home and overseas that it is “giving up” on the Fukushima region.

Another option would be to convert the water to solid form. Under this approach, low-level radioactive water that has been partially purified through ALPS would be mixed with cement and sand for pouring into concrete tanks.

This approach could be used to prevent the release of radioactive material into the sea. But because the solidification process increases the volume, it would also require significantly more land area.

“The Japanese government most likely did not see this as a viable choice because of the increased storage volume and the much greater costs compared with the ocean release approach or long-term storage in liquid form,” said Han Byeong-seop.

If reversing the ocean release decision is not an option, then it becomes important to pressure Japan into being transparent about disclosing information so that the extent of the risks can be accurately judged.

“Rather than simply heightening the sense of alarm too much, the administration and the Nuclear Safety and Security Commission (NSSC) should be taking action to calm the public’s fears,” said Park Jong-woon, a professor of nuclear systems engineering at Dongguk University.

“A rational approach would be to transparently disclose quantified numbers showing what level of risk is associated with the discharge of contaminated water from Fukushima,” he added.

The NSSC sent a letter Wednesday to the Japanese Nuclear Regulation Authority to demand monitoring of the disposal of contaminated water from Fukushima and prompt and transparent sharing of the findings.

By Kim Min-je, staff reporter

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