A task force created after the accident at the nuclear plant, Fukushima Daiichi, delivered an oral progress report on Wednesday to the five-member commission. Charlie Miller, the chairman of the task force, said that studies by safety experts in the United States had analyzed the risk of losing electricity from the grid or from on-site emergency generators, but not both at the same time.
Steven P. Kraft, an executive of the Nuclear Energy Institute, the industry's trade association, speaking after the meeting said that in the past it was "not considered credible" that a single event could knock out both supplies. In view of recent events, he said, it is time to prepare for the possibility of an extended blackout.
One of the commissioners, George E. Apostolakis, pointed out that existing safety analyses also assume that electricity will be restored within four or eight hours after a power cutoff, but that blackouts on the grid often last far longer. "Why do we still assume things that are now, in retrospect, unrealistic?" he asked.