The nuclear disaster that has gripped Japan since March was not unforseen because engineers there ignored key safety and seismic and tsunami data, a member of the Nuclear Regulatory Commission said.

NRC Commissioner George Apostolakis, a Democrat, today cited reports that found Japanese engineers did not appropriately use historical tsunami data when building a sea wall to protect the Fukushima Daiichi plant. On March 11, a magnitude-9 earthquake and tsunami struck the Fukushima reactor complex on the country's northeastern coast, triggering explosions, radioactive leaks and multiple evacuations. Experts believe a 46-foot tidal wave topped the existing wall and knocked out power needed to protect the wrecked plant during an emergency (ClimateWire, March 25).

Engineers miscalculated the strength of the earthquake, Apostolakis said. Further, they didn't consider that 10 earthquakes magnitude 8.4 or smaller that occurred around the world during the past decade were followed by tsunamis, two of which had a height greater than 10 meters, he said. Tokyo Electric Power Co., which operates the Fukushima plant, has since said it will build a sea wall to stop a 33-foot tsunami (Greenwire, May 2).

"This focus on the unthinkable is really misplaced; it was not unthinkable at all," Apostolakis said at a Bipartisan Policy Center event today on the Fukushima accident. "If anyone was doing the calculation of tsunamis in the United States and ignored that evidence, the NRC would complain ... you can't do that."

Risk assessments show the likelihood of such a catastrophe was "completely unacceptable in the reactor safety arena" and that the NRC would have taken different measures to protect the plant from such an event.

"This is the kind of secret that everybody knows but nobody wants to say anything public, let alone the management of the accident, which was also pretty bad," he said.

The United States assembled a task force to pull lessons from the Japanese disaster, and the panel's experts released a dozen safety recommendations last month. The expert group is recommending that NRC strengthen its regulatory oversight, require plant operators to re-evaluate and upgrade earthquake and flood risks, secure backup power and instrumentation to monitor and cool spent fuel pools, and handle lengthy losses of electric power to the plants.

The task force found that a catastrophic event like what happened in Japan is unlikely in the United States, and that the country's nuclear power plants are operating safely. That news is "comforting," Apostolakis said, and gives the NRC time to deliberately work through safety recommendations.

He also rebuffed criticism that he and other commissioners want to suppress or slow the implementation of such safety proposals by first seeking input from NRC senior management. "A lot of people immediately think that if you say that, 'Ah, you want senior management to suppress some of the recommendations of the near-term task force; you're a bad person,'" he said.

Senate Democrats scolded NRC commissioners yesterday for voting to obtain more input from NRC staff before prioritizing and moving forward with the recommendations (Greenwire, Aug. 2). NRC Chairman Gregory Jaczko -- the only member of the commission who has not yet voted -- wants the agency to decide within 90 days how to move forward.

Senate Environment and Public Works Chairwoman Barbara Boxer (D-Calif.) was critical of NRC members for requesting more analysis before proceeding and said the five-member panel would be asked to testify every three months until the issue is addressed. Apostolakis said Boxer was defending Jaczko's 90-day proposal, and that his approach -- and incorporating input from senior staff -- could also be completed within three months.

"It's a matter of structuring the process a little different," he said.