Chernobyl vs. Fukushima: Which Nuclear Meltdown Was the Bigger Disaster? via Live Science

By Mindy Weisberger, Senior Writer 

The new HBO series “Chernobyl” dramatizes the accident and horrific aftermath of a nuclear meltdown that rocked the Ukraine in 1986. Twenty-five years later, another nuclear catastrophe would unfold in Japan, after the magnitude 9.0 Tohoku earthquake and subsequent tsunami triggered a disastrous system failure at Fukushima Daiichi Nuclear Power Plant.

Both of these accidents released radiation; their impacts were far-reaching and long-lasting.

But how do the circumstances of Chernobyl and Fukushima compare to each other, and which event caused more damage? [5 Weird Things You Didn’t Know About Chernobyl]

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“As a result, more fission products were released from the single Chernobyl core,” Lyman told Live Science. “At Fukushima the cores overheated and melted but did not experience violent dispersal, so a much smaller amount of plutonium was released.”

In both accidents, radioactive iodine-131 posed the most immediate threat, but with a half-life of eight days, meaning half of the radioactive material decayed within that time, its effects soon dissipated. In both meltdowns, the long-term hazards arose primarily from strontium-90 and cesium-137, radioactive isotopes with half-lives of 30 years.
And Chernobyl released far more cesium-137 than Fukushima did, according to Lyman.

“About 25 petabecquerels (PBq) of cesium-137 was released to the environment from the three damaged Fukushima reactors, compared to an estimate of 85 PBq for Chernobyl,” he said (PBq is a unit for measuring radioactivity that shows the decay of nuclei per second).

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In the years that followed, cancers in children skyrocketed in the Ukraine, up by more than 90%, according to Time. A report issued by United Nations agencies in 2005 approximated that 4,000 people could eventually die of radiation exposure from Chernobyl. Greenpeace International estimated, in 2006, that the number of fatalities in the Ukraine, Russia and Belarus could be as high as 93,000 people, with 270,000 people in those countries developing cancers who otherwise would not have done so.

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No-go zones
Japanese authorities created a no-go zone around Fukushima that extended for 12 miles (20 kilometers); the damaged reactors were permanently closed, while cleanup efforts continued.

The extent of Fukushima’s environmental impact is still unknown, though there is already some evidence that genetic mutations are on the rise in butterflies from the Fukushima area, producing deformations in their wings, legs and eyes. [See Photos of Fukushima’s Deformed Butterflies]

Radiation from contaminated water that escaped Fukushima reached North America’s western coast in 2014, but experts said that contamination was too low to pose a threat to human health. And in 2018, researchers reported that wines produced in California after the Fukushima accident had elevated levels of radioactive cesium-137, but the California Department of Public Health declared that the wines were not dangerous to consume.

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The Fukushima nuclear power plant is still open and active (though the reactors that exploded remain closed); nonetheless, ongoing concerns about safety linger. The Tokyo Electric Power Company (TEPCO) recently announced that it would not hire foreign workers coming to Japan under newly relaxed immigration rules; TEPCO representatives cited concerns about the ability of non-native Japanese speakers to follow the plant’s highly detailed safety instructions, The Japan Times reported yesterday (May 23).

In the end, both disasters provided important lessons for the world on the inherent risks of using nuclear energy, Lyman told Live Science.

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