The water will be re-treated, multiple times if necessary, and diluted more than 100 times to bring its tritium radioactivity concentration down to no more than 0.0000000015 TBq per liter, a level equivalent to a 1/40 of Japan’s national safety standards. Tepco is regularly testing the stored water ahead of the release, the company says. The Cap de la Hague nuclear processing site in France releases 11,400 terabecquerels (Tbq) of tritium every year, which is more than 13 times the total radioactivity of the tritium across every storage tank at Fukushima. What many people don’t realize is that water containing tritium is actually routinely released into the sea-sometimes in vastly greater quantities than are to be discharged from Fukushima-by nuclear facilities all around the world, including in the US, Europe, and East Asia. The authors of one 2018 study speculated that unusually high levels of tritium in the Rhône river delta in France were down to historical pollution from the watchmaking industry-tritium has been used to make glow-in-the-dark paint for watch dials. Plus, tritium-one of the isotopes that can’t be removed from the stored water-is already present all around us at low concentrations, though higher levels are associated with nuclear-related activities. “We know radiation damages DNA, probably there are subtle effects of radiation at these levels, but we don’t generally see a significant effect on the ecosystem,” he says, referring to that work. Even there, where exposure to radiation is much greater, the impact appears to be tiny. Once the discharge begins, radionuclides will undoubtedly spread out into the Pacific, but this is very unlikely to have a noticeable effect on the environment, Smith says.įor context, he points out that he has many years of experience studying the effects of radiation on living things near the destroyed nuclear power plant in Chernobyl. One study found them floating around 3,000 km away in the Arctic Ocean six years after the accident. Many of the above radioactive isotopes were released into the ocean at the time of the disaster in 2011-and some traveled.
“I’m not concerned,” he says of the plan to discharge the water. There are also some isotopes the system can’t remove at all, such as carbon-14 and tritium, a form of hydrogen with two neutrons and one proton in its nucleus (hydrogen usually contains just one proton).ĭespite this, the water is extremely safe because the concentrations of radionuclides are so low, explains Jim Smith, a professor of environmental science at the University of Portsmouth. However, it is not 100 percent effective, and many of the radionuclides it’s designed to extract, such as the isotopes caesium-137 and strontium-90, for example, can still be found in the stored water. If there is a significant bump in radiation levels in the surrounding waters, it will mean things have gone very wrong. The water release could start as early as next month. The lids of the jars close automatically, one by one, as the device is slowly pulled back up to the surface.īy doing this, and also taking sediment samples from the seabed, they hope to be able to tell in the coming months and years whether the disposal of water from Fukushima is causing a noticeable rise in radiation in this corner of the Pacific Ocean. Casacuberta Arola and her colleagues regularly drop an assembly of jars into waters near the incapacitated power plant to collect samples at different depths. “We have access to a ship that goes to the coast of Fukushima every year, sometimes once, sometimes twice,” she says. Núria Casacuberta Arola, of ETH Zürich, is among those who will be watching. The water will soon be diluted and pumped into the sea. The eggs, made of steel, are tanks brimming with radioactive fluid-contaminated water from Japan’s Fukushima nuclear plant. In satellite pictures, they look like the pale blue and gray eggs of a giant butterfly, laid in tight patterns on some dismal leaf.
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