Expert on vulnerability of Japan’s nuclear plants to volcanoes: ‘They’re not safe’

A panel of experts in Japan contradicts regulators’ claim that nuclear power plant is safe in case of possible volcanic eruption.

After the 2011 Fukushima nuclear power plant disaster following a 9.0 magnitude earthquake, Japanese regulators enacted tougher safety requirements. Last month, they announced the Sendai nuclear power plant in southern Japan had passed those tough requirements and predicted there would be no major volcanic eruption in the area over the next 30 years, when the reactors reach the end of their lifespan.

But now, a well-known volcanologist is disputing the regulators’ conclusions, saying an eruption by one of several volcanos could hit the nuclear reactor and cause a nationwide disaster, according to a report by the Associated Press (AP).

University of Tokyo professor emeritus Toshitsugu Fujii , who heads a government panel on volcanic eruption prediction, says it is impossible to predict an eruption more than days or hours ahead of time.


An eruption of the still active Mount Sakurajima—part of the larger Aira Cauldron—that took place 90,000 years ago near the Sendai power plant in Kagoshima prefecture spewed pyroclastic flow as far as 90 miles (145 kilometers) away, according to several studies. A similar eruption today could easily reach the Sendai nuclear plant, which is located only 25 miles (40 kilometers) away, Fujii says.

A heavy rain of ash from a volcanic eruption would make reaching or leaving the power plant impossible and also could affect other parts of the country, including Tokyo and other nuclear operations in western Japan, according to Fujii. Heavy ash would render vehicles, except for tanks, inoperable, cause electrical blackouts, and potentially cut off electricity to the reactor’s cooling system.

Regulators have put together a panel of volcano experts to examine the impact of volcanic eruptions and ways to mitigate them—not before deeming the Sendai reactor safe, however.

Fujii says the panel’s experts do not agree with the regulators about the safety of the Sendai power plant. And while catastrophic eruptions occur on average every 10,000 years or so, it is unwise to categorically rule out that possibility, he warns.

“Scientifically, they’re not safe,” Fujii said about the Sendai reactors in the AP report. “If they still need to be restarted despite uncertainties and risks that remain, it’s for political reasons, not because they’re safe, and you should be honest about that.”

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