Fukushima disaster: New information about worst-case scenarios.

Much of What You’ve Heard About the Fukushima Nuclear Accident Is Wrong

Much of What You’ve Heard About the Fukushima Nuclear Accident Is Wrong

The state of the universe.
Sept. 26 2013 11:23 AM

Fukushima’s Worst-Case Scenarios

Much of what you’ve heard about the nuclear accident is wrong.

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Kondo concluded that the areas that might require evacuation did not extend close to Tokyo. If the worst happened, people living within a radius of about 30 miles from the plant "should be advised to evacuate before Day 14, when the emission would be expected to be full-blown," and some spots outside of that radius might also merit evacuation, he wrote in a 15-page report to top government ministers.

So if Kondo's scenario didn't envision the need to evacuate Tokyo, what exactly did it say regarding the capital? This is where media reports grossly misrepresented the findings; to understand why, a little background is in order about how the response to a nuclear event is supposed to work.

Girl aboard a bus evacuating from Yamagata
A girl looks out from a bus window as people rush to get out of Yamagata, Japan, on March 15, 2011.

Photo by Mike Clarke/AFP/Getty Images

Kondo’s exercise involved a longer time frame than the U.S. one did. The Americans were focused mainly on what specialists call the "early phase" of a nuclear accident—when an atmospheric plume containing radioactive particles causes exposure mainly from inhalation, in which case authorities are supposed to keep people sheltered in their homes (possibly giving them potassium iodide pills) or evacuate them depending on the type and concentration of particles in the plume. Kondo also included calculations about the “intermediate phase” and "late phase," when people are exposed over long periods to particles deposited on their skin, clothing, and on the ground; dispersed in the food and water they consume; and recirculated in the air they breathe. The time frame for the late phase is measured in decades—up to 50 years—because the cumulative lifetime dose matters. The chances of getting cancer are estimated to increase by 0.5 percent for a person exposed to a lifetime total of 100 millisieverts, and the risk increases further with higher doses. If an area is likely to come unacceptably close to those sorts of dose levels over a number of years, authorities have a reasonable amount of time to try a variety of protective actions, including controlling food and water sources, decontaminating land and buildings, etc. Those steps would ideally reduce exposures to acceptable levels, though if not, the relocation of inhabitants would be in order.


To determine what sort of later-phase response might be necessary if the worst happened at Fukushima, Kondo used land contamination levels based on the restrictions that were imposed after the Chernobyl disaster. He concluded that “compulsory relocation” might be required for some areas 105 miles from the plant and “acceptance of voluntary relocation” for some areas 155 miles away.

Anti-nuclear protest on 1st annicersary of earthquake and tsunami
Anti-nuclear protesters in Tokyo demonstrate against the Japanese government's nuclear policyon March 11, 2012, one year after an earthquake and tsunami prompted a nuclear accident at the Fukushima Dai-ichi nuclear power plant.

Photo by AFP/Getty Images

As bad as such an outcome might have been, the press made it sound exponentially worse when Kondo's projections became public in early 2012. Since Tokyo is less than 155 miles from the plant, the capital definitely would have been affected, many news stories claimed—even though that would have depended on the direction and strength of the winds, which might well have blown out to sea or somewhere else in the middle of Japan. And journalists (both foreign and Japanese) used the term “evacuation” in this context, as if Kondo had meant to say that a rushed mass exodus would have been warranted from any area affected by late-phase exposure concerns.

The Asahi Shimbun, a leading daily, said that under Kondo’s scenario the Japanese government “would have requested the evacuation of everyone within a [155 mile] radius” and “would have ordered mandatory evacuations of everyone within a [105 mile] radius.” Accompanying the Asahi’s article was a map showing a huge swath of Japan's main island of Honshu, including Tokyo, from which people would have been sent packing. Likewise, the Wall Street Journal reported that the scenario would have resulted in “the evacuation of people as far as 155 miles from the plant, including all of the Tokyo metropolitan area.” 

Asked why he didn't object to the wild exaggeration of his scenario in such articles, Kondo told me: "When I gave the report to Mr. [Goshi] Hosono [who had been appointed nuclear disaster minister], the job was completed. I was not in a position to comment on the news, even if anything was misinterpreted. My duty was to be understood by Mr. Hosono."

Then again, one scenario even worse than Kondo’s was circulating at the highest levels of the Japanese government early in the crisis.

* * *

"A devil's chain reaction" is the term used by Yukio Edano, the former chief government spokesman, to describe a scenario he and other petrified members of the government contemplated during the disaster.

Fukushima Daiichi nuclear power plant's No.4 reactor
The crippled Fukushima Dai-ichi nuclear power plant's No.4 reactor building is seen through bus windows in Fukushima, Japan, on Nov. 12, 2011.

Pool photo by David Guttenfelder/Reuters

The chain would start with TEPCO's withdrawal of all its personnel from Fukushima Dai-ichi. Once high radiation levels from that nuclear plant reached other nuclear plants in the region, crews would leave those plants unmanned as well, leading inevitably to more meltdowns and spent fuel fires. "We would lose Fukushima Dai-ni, then we would lose Tokai," Edano was quoted as saying in the report released last year by the Independent Investigation Commission, a private panel of distinguished citizens established to probe the accident. “If that happened, it was only logical to conclude that we would lose Tokyo itself."

This scenario had no scientific basis, as Edano has admitted; it was essentially a politician’s phantasmic mental exercise. None of that stopped the media from trumpeting his words.

On the top of the front page of its Feb. 27, 2012, edition, the New York Times quoted him prominently in its story about the commission’s report. "Japanese leaders ... secretly considered the possibility of evacuating Tokyo, even as they tried to play down the risks in public, an independent investigation into the accident disclosed," said the Times, citing Edano's "chain reaction." Similar articles appeared in major news outlets all over the world.

Contrast that with what happened a couple of weeks later, when an article in the scholarly magazine Foreign Affairs revealed the basic facts about the U.S. government’s worst-case scenario. Titled "Inside the White House During Fukushima," the article was written by Jeffrey Bader, who had chaired a number of the interagency meetings in his capacity as the National Security Council's senior director for East Asian affairs. Suggesting that the anxieties about a Tokyo evacuation had been vastly overblown, the article succinctly summarized the U.S. government’s findings: “There was no plausible scenario in which Tokyo, Yokosuka, or Yokota could be subject to dangerous levels of airborne radiation.”

Japan's Fukushima Dai-ichi nuclear plant
A construction worker walks near water tanks at the Fukushima Dai-ichi nuclear plant in Okuma, Japan, on June 12, 2013.

Photo by Toshifumi Kitamura/AFP/Getty Images

No plausible scenario—rather different an assessment than that suggested by the “devil’s chain reaction” and rather more credible given the scientific reasoning that underpinned it. Yet Bader's revelations got no coverage except for a report by the Kyodo wire service that was carried in some local Japanese papers. To my knowledge, the only journalist who has bothered to research the U.S. scenario in any depth is Yoichi Funabashi, the former editor of the Asahi Shimbun—and ironically, the chairman of the Independent Investigative Commission. Funabashi’s book Countdown to Meltdown, newly published in Japan, contains an account of the scenario, though it is not based on internal U.S. documents.

Nobody can say for sure how events would have unfolded if the worst had happened at Fukushima. Even the most sophisticated computer models are fallible.

But the public deserves to know what the best available science shows. Whatever conclusions people draw about the implications of the accident, the following should be borne in mind: The claim that an evacuation of Tokyo could have been necessary is based on flimsy, easily rebuttable evidence. Furthermore, the falsity of that claim is indicative of the distortions in much of the Fukushima news coverage. That coverage has given rise to baseless fears about Fukushima that have heavily influenced public opinion. It is time to dispel those fears.

A Japanese-language version of this article was previously published in Newsweek Japan.