Butterfly Wings and Nuclear Disasters, Part 2: The Missed Warnings

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On Monday, my colleague Jeffrey Kluger wrote an insightful post, “Butterfly Wings and Nuclear Disasters,” about how—with all respect to the Greek dramatists— there really is no such thing as a single “tragic flaw”; rather, tragedy results most often in the real world from the accumulation of small but significant mishaps. While that holds true for the sequence of events at Fukushima Daiichi power plant–earthquake cuts power, tsunami takes out back-up generators, batteries fail, and suddenly workers face a potential meltdown–it is also true that such a major disaster is almost always preceded by a series of warnings and alarm bells that, for whatever reason, were overlooked. In the case of Fukushima, multiple past warnings have already come to light:

• London’s Daily Telegraph today quoted from U.S. diplomatic cables made public by Wikileaks that showed that Japan was warned more than two years ago by the International Atomic Energy Agency that its nuclear power plants were not capable of withstanding powerful earthquakes. (The Fukushima plant was only designed to withstand a magnitude 7.0 quake; Friday’s earthquake was a magnitude 9.0 shock). A confidential diplomatic report following the G8’s Nuclear Safety and Security Group in Tokyo in 2008 reported how at the meeting, attended by Japan, an IAEA official “explained that safety guides for seismic safety have only been revised three times in the last 35 years and that the IAEA is now re-examining them. Also, the presenter noted recent earthquakes in some cases have exceeded the design basis for some nuclear plants, and that this is a serious problem….”

Writing in the Bulletin of the Atomic Scientists this week, Frank Von Hippel,  a former assistant director for national security in the White House Office of Science and Technology, writes about how the nuclear reactor safety community has long warned that over-pressurization in the case of overheating of reactor fuel would force plant operators to vent gas to prevent an explosion, and that this gas would be radioactive—this “venting” was precisely the action taken by Tokyo Electric Power which led to the initial evacuation order of the surrounding area. Hippel notes that in 1977, a group of nuclear engineers from the University of California suggested that robust filtration system be installed in reactors to remove any radioactivity from vented gas. Sweden picked up the idea, adding a filtered vent system to its reactors, as did France. Japan did not. In the wake of Three Mile Island in 1982, Hippel published an article calling for filtered vents to become mandatory. The article was ignored.

As I reported yesterday, there has long been concern over the safety of “spent fuel” at reactor sites. Because of a lack of approved long-term storage, nuclear power companies are densely packing spent fuel assemblies into cooling pools at reactor sites. Should cooling fail in these pools, the spent fuel can ignite and lead to a fire; as I write this, conditions at the spent fuel ponds at Fukushima seems to be deteriorating. A 2003 article in the  journal “Science and Global Security” titled “Reducing the Hazards from  Stored Spent Power-Reactor Fuel in the United States” warned that the ignition of spent fuel could lead to radioactive land contamination “significantly worse than Chernobyl.” That article, and others warning about the dangers of spent fuel, went unheeded.

• As the New York Times has pointed out, concerns were raised as far back as 1972 about the strength of a the primary containment vessel surrounding the “Mark 1” reactor design used at Fukushima. The concern was that the containment vessel, which is cheaper to build than other designs, would burst if the reactor fuel overheated.  According to the NYT, “In 1972, Stephen H. Hanauer, then a safety official with the Atomic Energy Commission, recommended that the Mark 1 system be discontinued because it presented unacceptable safety risks. Among the concerns cited was the smaller containment design, which was more susceptible to explosion and rupture from a buildup in hydrogen — a situation that may have unfolded at the Fukushima Daiichi plant. Later that same year, Joseph Hendrie, who would later become chairman of the Nuclear Regulatory Commission, a successor agency to the atomic commission, said the idea of a ban on such systems was attractive.” But a ban was never implemented.

No doubt further missed warnings will emerge in the aftermath of Fukushima, as will problems and mistakes that no one could have foreseen. Safety experts will learn much from what went wrong at Fukushima; but part of that education should come from trawling through the past and making sure no further safety warnings have been missed.