The following story originally appeared in NEI’s Nuclear Energy Overview.
The tsunami that brought about the nuclear accident at Japan’s Fukushima Daiichi facility was not adequately accounted for in the facility’s design basis, said a co-author of a report for the American Nuclear Society.
Michael Corradini, co-chair of the ANS’ special committee on Fukushima, told the National Academy of Sciences this week that the March 11, 2011, tsunami that disabled the nuclear power plant was not entirely unforeseen, because larger tsunamis have occurred in that region of Japan in recorded history.
Corradini said the historical tsunami threat would have been incorporated into the design basis for a similarly situated U.S. facility.
In describing the accident at Fukushima Daiichi, Corradini stressed that the units withstood the earthquake but not the tsunami, though both events exceeded the site’s design basis. “The safety systems survived the earthquake and operated quite normally,” Corradini said. “Following by 45 minutes or an hour, the tsunami … took out the safety systems.”
He added that Japan’s nuclear regulator is being restructured in part because of its failure to establish the proper design basis of the Fukushima Daiichi plant.
Corradini, who chairs the University of Wisconsin’s nuclear engineering program, said the report he co-authored with former NRC Chairman Dale Klein gathers publicly available details to provide “a clean and concise explanation of the events surrounding the accident.”
He said that safety benefits can be achieved in different ways and that site-specific factors—such as the risk of large tsunamis at Fukushima—must be taken into account in the design of a nuclear power plant.