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The Japanese government announced on April 13 that it would begin dumping the contaminated water into the ocean. (provided by the Tokyo Electric Power Company)

According to a new analysis, Japan will be forced to keep increasing the number of storage tanks for radioactive water at the Fukushima Daiichi Nuclear Power Plant even if it starts dumping that water into the ocean because more and more water is being contaminated.

“The amount of rainwater and groundwater that’s entering the site and being contaminated exceeds the amount of contaminated water that the authorities intend to discharge into the ocean. Building more [storage] tanks seems to be unavoidable,” the Asahi Shimbun, a Japanese newspaper, reported Monday.

The Japanese government announced on April 13 that it would begin dumping the contaminated water into the ocean. Since tritium, a radioactive isotope of hydrogen, cannot be removed by Japan’s Advanced Liquid Processing System, Japan intends to release up to 22 trillion becquerels of tritium into the ocean each year.

A becquerel (Bq) is a measure of radioactivity, representing one nuclear decay per second.

According to the Tokyo Electric Power Company (TEPCO) data, the average concentration of tritium in the contaminated water at Fukushima is 730,000 becquerels per liter (Bq/L). The yearly maximum of 22 trillion Bq of tritium would mean discharging a total of 30,000 tons of contaminated water.

The problem is that an average of 140 tons of water is being contaminated at the Fukushima plant every day, which TEPCO says amounts to around 50,000-60,000 tons over a year.

The authorities have to keep letting rainwater and groundwater flow into the coolant tank to cool the fuel rods that melted down during the accident at Fukushima in 2011. As a result, more and more water is being contaminated with radionuclides.

In effect, the amount of contaminated water that the Japanese government will have to store in tanks will increase by about 20,000-30,000 tons each year (depending on the amount of rainfall) even if it starts discharging the contaminated water into the ocean.

TEPCO aims to reduce the amount of water being contaminated each day to an average of 100 tons (about 36,000 tons a year) by 2025. But even in that case, the contaminated water requiring storage would still increase by several thousand tons each year.

“These are challenging results. We have no choice but to make [more] tanks,” a Japanese government official said in an interview with the Asahi Shimbun.

As of March 2021, Japan had set up 1,061 storage tanks capable of holding 1.37 million tons of contaminated water. The tanks currently hold 1.25 million tons of water or 91.2% of their capacity.

The Japanese government decided to release the contaminated water into the ocean over at least 30 years, beginning in two years, because the tanks will reach capacity by next fall.

By Kim So-youn, staff reporter

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