Fukushima Daiichi’s radioactive legacy

They’ve been called the Fukushima 50, as well as Japan’s “nuclear samurai.” We don’t know their names, nor their faces. Yet every minute since the twin disasters of a 9.0 magnitude earthquake and nine-metre tsunami rocked the Fukushima Daiichi nuclear power plant, they have stood as the last line of defence against a full-blown catastrophe. A lone dispatch posted by one of the workers online gave a hint of the terror they face: “Everyone at the power plant is battling on, without running away,” the worker, an employee of Tokyo Electric Power Company, wrote on her blog. “There are people working to protect all of you, even in exchange for their own lives.”

But while the world’s attention is focused on the plight of the workers and the immediate threat from the four mangled reactors at Fukushima, only now is the full scale of what’s occurred sinking in. As the fight to cool the reactors and spent fuel pools drags from days into weeks, it’s clear this crisis won’t come to a tidy end. There will be no definitive “mission accomplished” moment.

History can attest to that. After the No. 2 reactor at Pennsylvania’s Three Mile Island nuclear plant partially melted down in 1979, it took three years before officials could finally peek inside the superheated core with a tiny camera to survey the damage, and another eight years to safely remove and store its contaminated entrails. When the reactor at Chernobyl exploded in 1986 and sent a radioactive plume across much of Eastern Europe, 20 years passed before the World Health Organization was able to give a full reckoning of the human toll. To this day a 30-km exclusion zone surrounds the plant, an area in which people are legally prevented from living, though some original residents have returned.

Will officials need to establish a similar exclusion zone around Fukushima? How long will it take to clean up the site? And, most importantly, will the radiation that’s already escaped from the plant cause lasting health problems? Those are just a few of the lingering questions Japan has yet to grapple with. In other words, even when workers bring the reactors under control, the legacy of Fukushima is certain to loom for years and possibly decades to come.

The battle to tame the reactors has been one of see-sawing victories and setbacks. From the moment Mother Nature lashed out along Japan’s northeast coast on March 11, operators at the plant were on their heels. While the reactors automatically shut down when the quake hit—heading off a far greater disaster—the violent tremors knocked out the flow of electricity to the plant. Then when the tsunami washed over the plant, it destroyed the backup diesel generators. Suddenly operators had no way to power the cooling systems needed to prevent the uranium rods inside the core from overheating.

Normally cooling systems would keep the fuel rods submerged in water. But with no power to the plant, water levels quickly began to drop as water boiled off, allowing the rods to become exposed and their temperatures to soar. Some experts believe the rods have begun to break down under the immense heat and pressure, prompting fears of a partial meltdown.

An even greater threat emerged days later, though. After fuel rods are “spent,” they are transferred to deep pools located on an upper floor of the reactor buildings, where they’re kept cool. Unlike the reactors, which are contained in steel and concrete, the pools had little protection, and a series of explosions, caused by a buildup of hydrogen gas in the buildings, left the pools in a dangerous state. Some may be leaking, while surrounding heat has boiled off water. If the spent fuel rods are exposed to the air for too long—a mere matter of hours—their casings may catch fire and send radioactive smoke into the atmosphere. At one point last week U.S. Nuclear Regulatory Commission chairman Gregory Jaczko declared all the water in one of the pools at the No. 4 reactor was gone, sparking fears a deadly radioactive release was imminent.

As it turned out, helicopter pilots who later flew overhead saw water in the reactor pool. Jaczko’s warning, which he issued while testifying before Congress, was just one example of how the crisis has put the U.S. and Japan at odds. So far Japan has only evacuated residents from a 20-km radius around the plant. Meanwhile those living between 20 km and 30 km from the plant have been warned to stay indoors. But the U.S. and other countries, including Canada, have told their citizens to stay at least 80 km away from the plant.

Yet if the Japanese are angry with the blunt tone American officials have taken about the dangers posed by Fukushima, they’re also thankful for the support the U.S. has given. The U.S. military has provided clothing and equipment for fighting the radiological battle, drone aircraft to gather radiation readings and teams of nuclear experts.

The plant’s beleaguered workers have needed all the help they can get. From the start of the crisis, there was talk of “last-ditch efforts” to gain control of the reactors, yet at each turn more desperate measures have followed. After pumping sea water into the reactors to keep them cool, helicopters were then brought in to dump water on the reactors and pools. Workers have also used trucks outfitted with powerful water cannons to blast water through the skeleton frames of the reactor buildings, putting them dangerously close to the radiation. Along the way radiation spikes and ominous plumes of grey smoke have repeatedly forced workers to pull back. Like a stubborn game of radioactive whack-a-mole, as soon as operators seem to get a handle on problems at one reactor building, another crisis flares up somewhere else.

But there have also been hard-fought victories, and as of Tuesday, when Maclean’s went to print, it seemed fortune might finally favour the plant operators. Units five and six are now in cold shutdown, meaning the temperature inside the core is below 100° C. After constantly spraying water into the fuel pool at unit three, radiation levels were falling. Temperatures in all the pools had also fallen below 100 degrees.

One key to regaining control of the reactors will be to restore power to their built-in cooling systems, assuming they weren’t too damaged by the tsunami and hydrogen explosions. Crews managed to connect all six reactors to the existing power grid, some two kilometres inland. Power is flowing to units five and six, but officials said it could take several days before they’re ready to flick the switch on the cooling systems in the remaining reactors.

Already operators at the plant have defied the expectations of many who feared the worst. Edwin Lyman, a physicist at the Union of Concerned Scientists, said on a conference call that if the sea water pumping had not been effective, the reactors would have already suffered a meltdown. “It’s an amazing thing that they were able to maintain the cores in this state,” he said. “It is truly heroic.”

And yet we remain much closer to the beginning of the Fukushima saga than the end. As Andre-Claude Lacoste, head of the Paris-based Autorité de Sûreté Nucléaire, an independent nuclear safety authority, said at a press conference in Paris on March 21: “We are at the beginning of the post-accident phase. Japan will have to deal with the consequences of this accident for decades.”

How things play out in the coming weeks, months and even years depends a lot on what type of radioactive particles have been released, and how far they’ve spread, say experts. At this point, it’s still difficult to say exactly how much radiation has leaked out of Fukushima. In the immediate vicinity of the reactors, radiation levels hit extreme levels, but fall dramatically the further one moves away from the reactors. Still, health officials in Japan detected high levels of radiation in dairy products and on spinach grown near Fukushima. The government halted sales of those foods. Trace amounts of radiation have been found in Tokyo drinking water, though at levels too low to be harmful. Most recently, radiation was detected in sea water near the plant, raising concerns that it could contaminate fish, though again, the levels were low.

Not all radiation is the same, and this will also factor into how long the crisis lingers. The most common radioactive element that’s been released from Fukushima is iodine-131. The great concern with that element is that it attacks the thyroid gland, particularly in young children. Iodine-131 was responsible for a large number of the cancer cases after Chernobyl, but that was also due to the failure of officials to limit the consumption of food from around the stricken plant. Iodine-131 has a half-life of eight days—a measure of how fast it decays—and within three months it will be gone. A potentially more harmful element also released from Fukushima is caesium-137, a substance that emits gamma rays and, with a half-life of 30 years, some fear it could lead to increased cancer rates in the future. Meanwhile, the most dangerous element at Fukushima is plutonium, which was used as a fuel in reactor three, and has a half-life of 25,000 years. Fortunately no traces of it have been found outside the reactors.

Once the reactors and spent fuel pools are under control, researchers will begin detailed testing of the area around the plant. Only then will we know the extent of the radiation leak and what will be needed to clean it up. “It could be something as easy as scrubbing down the industrial site and being done with it,” says Alexander Sich, associate professor of physics at the Franciscan University in Steubenville, Ohio. “Or they may have to go out five miles and scrape off the top soil.”

As for the reactors and pools themselves, the cleanup will be long and slow, says Murray Jennex, a professor at San Diego State University in California, who did testing work at Chernobyl. The spent fuel may be kept on site for several years until it cools and can be transported to a permanent dry-storage site. It will probably be months before a robot can be sent in to examine the reactors.

What he doesn’t expect to see is any of the measures that were needed at Chernobyl, like a giant concrete sarcophagus or the infamous exclusion zone. “It’s a misnomer that Chernobyl was a no-go zone,” says Jennex. “It was a no-live zone, but people worked at the remaining reactors right up until the last one closed in 2000.” Indeed, today the area is a wildlife refuge, and has become a popular vacation spot for Ukrainians known as the “Chernobyl Riviera.” In Japan, there may be an area a few kilometers around the plant where people are not permitted to live, he says, but houses near there were already destroyed by the tsunami and the government is planning to move people further inland anyway.

Ultimately it is the workers at the plant who are truly at risk. This is how it was for the heroes at Chernobyl, too. Anatoly Grishchenko was one of several helicopter pilots who flew emergency missions to dump wet concrete over the molten reactor. He spent three months on the scene, and was feted as a “hero of the world” for his work. Four years after the reactor was sealed, Grishchenko died of acute leukemia at a specialized cancer hospital in Seattle where he’d been brought for treatment. In all, of the 50 deaths the World Health Organization directly attributed to radiation from Chernobyl, almost all were emergency workers, many of whom died within months of the accident.

There is one way Fukushima will be like both Three Mile Island and Chernobyl. Previously an overlooked and unknown blip on a map, it will forever be remembered not as a place, but a terrifying nuclear event.