'Never Again' Is a Hard Promise to Keep

Two hundred feet up in the foothills that surround Aneyoshi, a tiny coastal village in Japan, warnings are engraved into the rocks. Most of the messages come from 19th-century survivors of large tsunamis that terrorized people along the coast. "High dwellings are the peace and harmony of our descendants," one inscription declares. "Remember the calamity of the great tsunamis. Do not build any homes below this point."

But more recent residents of coastal Japan did build below that point. Homes at first, but eventually nuclear facilities, which were built where they could be cooled by nearby ocean waters. On March 11, 2011, a massive undersea earthquake occurred east of Oshika Peninsula. The quake, which lasted six minutes and remains the fourth-most powerful ever recorded in the world, triggered tsunami waves that reached up to 130 feet above sea level. The rushing water ultimately led to a meltdown at the Fukushima Daiichi nuclear facility, where a loss of power shut off the cooling system, resulting in hydrogen-gas accumulation. As surprised workers tried to cool the facility manually—using water from fire trucks—a gas buildup led to the expulsion of radioactive material into the atmosphere and groundwater. Part of Fukushima prefecture is still uninhabitable.

After the nuclear disasters at Three Mile Island in 1979 and Chernobyl in 1986, investigators blamed a combination of mechanical failure and operator error. The conventional narrative of Fukushima Daiichi's demise has been somewhat more forgiving of the people running the plant that day. The earthquake and tsunami could not be blamed on them. The most fundamental error, news stories intimated, was putting a nuclear reactor in a location so obviously vulnerable to natural disaster. Previous generations had literally carved warnings in stone: Never again. Because TEPCO, the plant's operator, had ignored them and built in a risky spot, tragedy was all but inevitable.

This made a tidy story, except for one thing: The Onagawa nuclear-power plant also sits below the rock warnings, but it withstood the earthquake and tsunami. Onagawa was about 30 miles closer to the epicenter of the earthquake than the Daiichi facility was. It experienced the strongest ground shaking of any of the nuclear facilities in the area—or indeed of any nuclear facility in recorded history. Operated by the Tohoku Electric Power Company, the Onagawa reactor did not melt down. It suffered no serious damage. The differing fates of Fukushima Daiichi and Onagawa cannot be explained by the movement of the Earth, because neither plant heeded the century-old warnings....