Japan creates the next environmental disaster with Fukushima cooling water

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First tests for the controversial release of the tritiated water have begun.

The time has come: In Fukushima, the first tests have begun to release the cleaned cooling water, which is still contaminated with tritium, from the damaged Fukushima Daiichi nuclear power plant. The plan is to dilute the approximately 1.25 million tons of water containing tritium and channel it about one kilometer into the sea via a tunnel.

The initiation could begin in a few weeks.

While fishermen and environmental organizations protest, operator Tepco emphasizes that the discharged tritium will hardly change the natural tritium content of the Pacific.

In March 2011, an earthquake and tsunami led to a serious nuclear accident at Japan’s Fukushima Daiichi nuclear power plant. Since then, the damaged reactors have had to be cooled, which, due to numerous leaks, produces around 150 tons of radioactive cooling water every day. More than 1.2 million tons of it are now stored in a good thousand tanks on the power plant site. The water contains varying doses of 61 radionuclides – including radioactive strontium, cesium, iodine and cobalt.

Aus den Tanks ins Meer

A few years ago, the power plant operator Tepco installed a special treatment system, the so-called “Advanced Liquid Processing System” (ALPS), to purify this water. According to the operator, this removes all radionuclides from the water apart from radioactive tritium. However, leaked documents in 2019 suggested that the ALPS system was performing less well than Tepco claimed. In addition to tritium, other radioactive nuclides should also continue to be included.

Nevertheless, in 2021 the Japanese government approved the plan to discharge the cleaned cooling water diluted into the sea from 2023 – despite protests from fishermen, environmental organizations and countries neighboring Japan. A system of pumps and tunnels was built for the discharge, which ends in the open ocean about a kilometer off the coast.

Tests for the initiation have started

Now the initiation is imminent: On June 19, the first tests of the pumping systems in Fukushima began, initially with clean water. According to Tepco, these tests will last two weeks before a series of official reviews by Japan’s Atomic Energy Agency in early July. If these tests go as planned, the discharge of the tritiated water into the Pacific could then begin.

But what does this mean for the ocean and the marine environment? How high is the radioactive contamination? According to the International Atomic Energy Agency (IAEA), the quantities of radioactive tritium released into the Pacific are harmless because they dilute very quickly and because tritium is naturally contained in small amounts in all seawater. According to IAEA tests from early 2023, the concentrations of radionuclides other than tritium in the purified water should be well below legal limits.

criticism and distrust

However, not all critics are convinced of this. “Japan’s plan to discharge the treated, contaminated cooling water into the Pacific is premature and ill-advised,” said University of Hawaii oceanographer Robert Richmond. The radiological environmental impact assessment presented by Tepco is inadequate and incomplete, the same applies to the monitoring plans. In these, for example, no precautions were taken to protect the marine environment in the event of a malfunction.

Japanese and South Korean fishermen also continue to protest against the planned discharge of the Fukushima cooling water. They see their livelihood threatened. Radiation researcher Tony Hooker from the University of Adelaide is also critical of the plan: “Even if this introduction may meet the scientific and regulatory requirements, it remains questionable whether we can continue to use the sea as a landfill when our oceans are already polluted.” , according to the researcher.

What happens to the tritium in the ocean?

The physicist Nigel Marks from Curtin University in Australia explains what the discharged amount of tritium means for the ocean in concrete terms: “The Pacific Ocean contains around 8,400 grams of pure tritium, while Japan will discharge around 0.06 grams of tritium per year in Fukushima”. In his view, extra tritium will therefore make no difference. Other researchers estimate that it will take around 30 years for a good 80 percent of the radioactivity from the introduced tritium to be lost.

In 2021, scientists used model simulations to study how the tritium introduced in Fukushima will then spread in the Pacific. According to this, most of the tritium will spread eastward across the equatorial Pacific. After three years, it could then also reach the west coast of the USA – possibly even in higher concentrations than on the coasts of Japan and China.

Quelle: Science Media Centre New Zealand, IAEA

Von Nadja Podbregar