Sun, Oct 06, 2019 - Page 5 News List

Fukushima facing million-tonne headache


Storage tanks for contaminated water stand at the Fukushima Dai-ichi nuclear power plant in Japan on Jan. 31 last year.

Photo: AFP

On the grounds of the ravaged Fukushima Dai-ichi nuclear power plant sits a million-tonne headache for the plant’s operators and the Japanese government: tank after tank of water contaminated with radioactive elements.

What to do with the enormous amount of water, which grows by about 150 tonnes a day, is a thorny question, with controversy surrounding a long-standing proposal to discharge it into the sea, after extensive decontamination.

The water comes from several different sources: Some is used for cooling at the plant, which suffered a meltdown after it was hit by a tsunami triggered by a massive earthquake in March 2011.

Groundwater that seeps into the plant daily, along with rainwater, add to the problem.

Tokyo Electric Power Co (Tepco) has been battling with the problem for years, taking various measures to limit the amount of groundwater entering the site.

A thousand towering tanks have now replaced many of the cherry trees that once dotted the plant’s ground. Each can hold 1,200 tonnes and most of them are full.

“We will build more on the site until the end of 2020 and we think all the tanks will be full by around the summer of 2022,” said Tepco general manager Junichi Matsumoto, who heads the unit in charge of dismantling the site.

There is an extensive pumping and filtration system, which each day brings up tonnes of newly contaminated water and filters out as many of the radioactive elements as possible.

The hangar where the decontamination system runs is designated “Zone Y” — a danger zone requiring special protections.

All those entering must wear elaborate protection: a full-body suit, three layers of socks, three layers of gloves, a double cap topped by a helmet, a vest with a pocket carrying a dosimeter, a full-face respirator mask and special shoes.

Most of the outfit has to be burned after use.

“The machinery filters contain radionuclides, so you have to be very protected here, just like with the buildings where the reactors are,” Tepco risk communicator Katsutoshi Oyama said.

Tepco has been filtering newly contaminated water for years, but much of it needs to go through the process again, because early versions of the filtration process did not fully remove some dangerous radioactive elements, including strontium 90.

The process has become more effective, removing or reducing about 60 radionuclides to levels accepted by the International Atomic Energy Agency (IAEA) for water being discharged.

However, there is one that remains, which cannot be removed with current technology: tritium.

Tritium is naturally present in the environment and has also been discharged in its artificial form into the environment by the nuclear industry around the world.

There is little evidence that it causes harm to humans except in very high concentrations, and the IAEA has said that properly filtered Fukushima water could be diluted with seawater and then safely released into the ocean without causing environmental problems.

However, those assurances are of little comfort to many in the region, particularly Fukushima’s fishing industry which, like local farming, has suffered from the outside perception that food from the region is unsafe.

Kyoichi Kamiyama, director of the radioactivity research department at the regional government’s Fisheries and Marine Science Research Center, said that local fishers are still struggling eight years after the disaster.

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