The Fight Over Fukushima’s Dirty Water


The numbers were climbing on a radiation dosimeter as the minibus carried me deeper into the complex. Biohazard suits are no longer required in most parts of Japan’s Fukushima Daiichi power plant, but still, I’d been given a helmet, eyewear, an N95 mask, gloves, two pairs of socks, and rubber boots. At the site of the world’s worst nuclear disaster since Chernobyl, you can never be too safe.

The road to the plant passes abandoned houses, convenience stores, and gas stations where forests of weeds sprout in the asphalt cracks. Inside, ironic signs, posted after the disaster, warning of tsunami risk. In March 2011, a 9.0-magnitude earthquake struck off Japan’s Pacific coast and flooded the plant, knocking out its emergency diesel generators and initiating the failure of cooling systems that led to a deadly triple-reactor meltdown.

Now, looking down from a high platform, I could see a crumpled roof where a hydrogen explosion had ripped through the Unit 1 reactor the day after the tsunami hit. The eerie stillness of the place was punctuated by the rattle of heavy machinery and the cries of gulls down by the water, where an immense metal containment tank has been mangled like a dog’s chew toy. Great waves dashing against the distant breakwater shook the metal decks by the shore. Gazing out across this scene, I felt like I was standing at the vestibule of hell.

A dozen years after the roughly 50-foot waves crashed over Fukushima Daiichi, water remains its biggest problem. The nuclear fuel left over from the meltdown has a tendency to overheat, so it must be continuously cooled with water. That water becomes radioactive in the process, and so does any groundwater and rain that happens to enter the reactor buildings; all of it must be kept away from people and the environment to prevent contamination. To that end, about 1,000 dirty-water storage vats of various sizes blanket the complex. In all, they currently store 343 million gallons, and another 26,000 gallons are added to the total every day. But the power plant, its operator claims, is running out of room.

On August 24, that operator—the Tokyo Electric Power Company, or TEPCO—began letting the water go. The radioactive wastewater is first being run through a system of chemical filters in an effort to strip it of dangerous constituents, and then flushed into the ocean and potentially local fisheries. Although this plan has official backing from the Japanese government and the International Atomic Energy Agency, many in the region—including local fishermen and their potential customers—are frightened by its implications.

“The IAEA has said this will have a negligible impact on people and the environment,” Junichi Matsumoto, a TEPCO official in charge of water treatment, told reporters during a briefing at Daiichi during my visit in July. Only water that meets certain purity standards would be released into the ocean, he explained. The rest would be run through the filters and pumps again as needed. But no matter how many chances it gets, TEPCO’s Advanced Liquid Processing System cannot cleanse the water of tritium, a radioactive form of hydrogen that is produced by nuclear-power plants even during normal operations, or of carbon-14. These lingering contaminants are a source of continuing anxiety.

Last month, China, the biggest importer of Japanese seafood, imposed a blanket ban on fisheries’ products from Japan, and Japanese news media have reported domestic seafood chains receiving numerous harassing phone calls originating in China. The issue has exacerbated tensions between the two countries. (The Japanese public broadcaster NHK responded by reporting that each of 13 nuclear-power plants in China released more tritium in 2021 than Daiichi will release in one year.) In South Korea, the government tried to allay fears after thousands of people protested in Seoul over the water release.

Opposition within Japan has coalesced around potential harms to local fishermen. In Fukushima, where the season for trawl fishing has just begun, workers are worried that seafood consumers in Japan and overseas will view their products as tainted and boycott them. “We have to appeal to people that they’re safe and secure, and do our best as we go forward despite falling prices and harmful rumors,” one elderly fisherman told Fukushima Broadcasting as he brought in his catch.

Government officials are doing what they can to protect that brand. Representatives from Japan’s environmental agency and Fukushima prefecture announced last week that separate tests showed no detectable levels of tritium in local seawater after the water release began. But even if its presence were observed, many experts say the environmental risks of the release are negligible. According to the IAEA, tritium is a radiation hazard to humans only if ingested in large quantities. Jukka Lehto, a professor emeritus of radiochemistry at the University of Helsinki, co-authored a detailed study of TEPCO’s purification system that found it works efficiently to remove certain radionuclides. (Lehto’s earlier research played a role in the development of the system.) Tritium is “not completely harmless,” he told me, but the threat is “very minor.” The release of purified wastewater into the sea will not, practically speaking, “cause any radiological problem to any living organism.” As for carbon-14, the Japanese government says its concentration in even the untreated wastewater is, at most, just one-tenth the country’s regulatory standards.  

[From 1976: Richard Rhodes on the benefits, costs, and risks of nuclear energy]

Opponents point to other potential problems. Greenpeace Japan says the biological impacts of releasing different radionuclides into the water, including strontium-90 and iodine-129, have been ignored. (When asked about these radionuclides, a spokesperson for the utility told me that the dirty water is “treated with cesium/strontium-filtering equipment to remove most of the contamination” and then subsequently processed to remove “most of the remaining nuclides except for tritium.”) Last December, the Virginia-based National Association of Marine Laboratories put out a position paper arguing that neither TEPCO nor the Japanese government has provided “adequate and accurate scientific data” to demonstrate the project’s safety, and alleged that there are “flaws in sampling protocols, statistical design, sample analyses, and assumptions.” (TEPCO did not respond to a request for comment on these claims.)

If, as these groups worry, the water from Fukushima does end up contaminating the ocean, scientific proof could be hard to find. In 2019, for example, scientists reported the results of a study that had begun eight years earlier, to monitor water near San Diego for iodine-129 released by the Fukushima meltdown. None was found, in spite of expectations based on ocean currents. When the scientists checked elsewhere on the West Coast, they found high levels of iodine-129 in the Columbia River in Washington—but Fukushima was not to blame. The source of that contamination was the nearby site where plutonium had been produced for the nuclear bomb that the U.S. dropped on Nagasaki.

Concerns about the safety of the water release persist in part because of TEPCO’s history of wavering transparency. In 2016, for instance, a commission tasked with investigating the utility’s actions during the 2011 disaster found that its leader at the time told staff not to use the term core meltdown. Even now, the company has put out analyses of the contents of only three-fifths of the dirty-water storage tanks on-site, Ken Buesseler, the director of the Center for Marine and Environmental Radioactivity at the Woods Hole Oceanographic Institution, told me earlier this summer. Japan’s environmental ministry maintains that 62 radionuclides other than tritium can be sufficiently removed from the wastewater using TEPCO’s filtration system, but Buesseler believes that not enough is known about the levels of those contaminants in all of the tanks to make this claim. Instead of flushing the water now, he said, it should first be completely analyzed, and then alternatives to dumping, such as longer on-site storage or using the water to make concrete for tsunami barriers, should be considered.

It looks like that radioactive ship has sailed, however. The release that began in August is expected to continue for as long as the plant decommissioning lasts, which means that contaminated water will continue to flow out to the Pacific Ocean at least until the 2050s. In this case, the argument over relative risks—and whether Fukushima’s dirty water will ever be made clean enough for dumping to proceed—has already been decided. But parallel, and unresolved, debates attend to nuclear power on the whole. Leaving aside the wisdom of building nuclear reactors in an archipelago prone to earthquakes and tsunami, plants such as Daiichi provide cleaner energy than fossil-fuel facilities, and proponents say they’re vital to the process of decarbonizing the economy.

Some 60 nuclear reactors are under construction around the world and will join the hundreds of others that now deliver about 10 percent of global electricity, according to the World Nuclear Association. Meltdowns like the one that happened in Fukushima in 2011, or at Chernobyl in 1986, are very rare. The WNA says that these are the only major accidents to have occurred in 18,500 cumulative reactor-years of commercial operations, and that reactor design is always improving. But the possibility of disaster, remote as it may be in any given year, is ever-present. For instance, the Zaporizhzhia Nuclear Power Station, Europe’s largest, has been threatened by military strikes and loss of electricity during the war in Ukraine, increasing the chances of meltdown. It took just 25 years for an accident at the scale of Chernobyl’s to be repeated.

[Read: Reckoning with the legacy of the nuclear reactor, 75 years later]

“We are faced with a difficult choice, either to continue using nuclear power while accepting that a major accident is likely to occur somewhere every 20 or 30 years, or to forgo its possible role in helping slow climate change that will make large swaths of the globe uninhabitable in coming decades,” says Azby Brown, the lead researcher at Safecast, a nonprofit environmental-monitoring group that began tracking radiation from Fukushima in 2011.

The Fukushima water release underscores the fact that the risks associated with nuclear energy are never zero and that dealing with nuclear waste is a dangerous, long-term undertaking where mistakes can be extremely costly. TEPCO and the Japanese government made a difficult, unpopular decision to flush the water. In the next few decades, they will have to show that it was the right thing to do.

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