For a final point of comparison, Smith calculates that cosmic rays interacting with Earth’s atmosphere over the Pacific Ocean annually cause the natural deposition of 2,000 times more tritium than will be introduced by the gradual release of Fukushima.
Tatsujiro Suzuki of Nagasaki University remembers watching the disaster in 2011 with horror. “We all thought something like this would never happen in Japan,” he says. He then worked for the government. He remembers the confusion over what happened to the reactors in the days after the tsunami. Everyone was gripped by fear.
“Once you’ve had an accident like that, you don’t want to see another one,” he says. The long shadow cast by the disaster means that the stakes for the drainage plan – at least in terms of public trust – couldn’t be higher.
Suzuki argues that it’s not entirely fair to compare Fukushima’s water to fluids discharged from other nuclear facilities elsewhere in the world because of the challenge of cleaning up the many different radionuclides here. “This is an unprecedented event, we haven’t done this before,” he says, adding that he thinks the procedure is “probably safe” but that there is still room for human error or an accident, such as another tsunami, that could cause an uncontrolled release of the water into the sea.
Tepco and the International Atomic Energy Agency have considered such possibilities and still assess the risk to humans and marine life as extremely low. Sameh Melhem, now with the World Nuclear Association, formerly worked for the Atomic Energy Agency and was involved in some of the research to evaluate the release plan. “I think it’s very safe for the operators themselves and also for the public,” he says, adding, “The radionuclide concentrations coming out of this release are negligible.”
Last November, Casacuberta Arola and her colleagues collected seawater samples off the coast of Fukushima, and they recently began analyzing them. The scientists measure the levels of various radionuclides that may be present. For tritium, that means removing all the helium from the sample and waiting to see how much new helium comes out of the water as a product of radioactivity. This makes it possible to extrapolate how much tritium should be present, explains Casacuberta Arola. She and her team have records of these types of radionuclide measurements from the sea off Fukushima going back years.
“We already know that the values we see now near Fukushima are close to the background values,” she says. If that changes, they should find out pretty quickly. As do the International Atomic Energy Agency and other observers, who separately plan to sample water and wildlife in the area in the coming years to keep an eye out.
Smith says that despite overwhelming evidence that the water discharge will be perfectly safe and heavily monitored at every turn, it’s not surprising that some people are skeptical of the plan. They are entitled to it, he adds, given the plant’s checkered history.
At the same time, the threat posed by the release – even in the worst-case scenario where everything goes wrong – is minimal compared to some of the region’s other environmental risks, such as the effects of the climate crisis in the Pacificsays Smith.
Casacuberta Arola agrees. Negative coverage of the layoff plan has been used to “brainwash” people, she argues, and to fuel fears about the nuclear power industry. “For me,” she adds, “it’s very over the top.”