TOKYO — As radiation spewed from Japan's nuclear disaster three years ago, the top U.S. atomic energy regulator issued a 50-mile evacuation warning for any Americans in the area, a response some found extreme.
Gregory Jaczko, who stepped down as chairman of the Nuclear Regulatory Commission in 2012, still believes he was right, and says the events at the Fukushima Dai-Ichi plant show that nuclear power should be phased out in Japan and worldwide.
"The lesson has to be: This kind of accident is unacceptable to society. And that's not me saying it. That's society saying that," he said in an interview this week in Tokyo, where he is giving lectures and speaking on panels marking the third anniversary of the March 11, 2011 earthquake and tsunami that overwhelmed the Fukushima plant.
Now a lecturer at Princeton University, Jaczko, 43, has become a hit on the speaking circuit in Japan, where all 48 nuclear plants remain offline as the country debates what role nuclear power should play in its future.
The government is pushing forward with a plan to restart several reactors after safety checks, despite continuing public opposition. Nuclear regulators announced Thursday they are beginning the final approval process for the restart of two reactors at a plant on the southernmost main island of Kyushu.
Jaczko said he had always been concerned about nuclear safety. But so much unfolded at Fukushima that experts were unprepared for, that it changed his view, and that of the Japanese public, on nuclear power.
Chernobyl and Three Mile Island were major accidents, but for Jaczko, Fukushima definitively undermined industry assumptions such as multiple accidents were unlikely or hydrogen leaks would be controlled.
Three of the reactors at the Fukushima Dai-ichi plant had meltdowns, and two had hydrogen explosions. The idea that a plant wouldn't be under control three or four days after an accident was unthinkable before Fukushima, he said.
"We have defined safety measures against the things that we kind of know. An accident is going to be something that we didn't predict," he said.
During the Fukushima crisis, the Nuclear Regulatory Commission staff discussed possible evacuation zones of between 20 miles and 50 miles, and given the uncertainty, opted for 50 miles, he said. A 50-mile evacuation has never been adopted as a standard for disaster scenarios in the U.S.
Jaczko said it was luck the wind blew in a direction that sent much of the radiation out to sea.
His resignation from the NRC, three years into his five-year term as chairman, followed complaints about his management style. He says he could no longer support the licensing of reactors in the U.S. after Fukushima.
Yotaro Hatamura, an honorary professor at the University of Tokyo who took part in a government investigation of Fukushima, said the right decision on nuclear power can't be made without addressing the what-if scenarios of accidents.
"A true debate is needed, but all we're getting is: Are you for or against nuclear power?" he said, sitting with Jaczko on a recent panel at the Japan Press Center.
Follow Yuri Kageyama on Twitter at twitter.com/yurikageyama