A team of experts says U.S. nuclear safety rules do not sufficiently take into account the risk that a single event could knock out power from the nation’s grid and emergency generators. A task force with the U.S. Nuclear Regulatory Commission said safety equipment installed at a number of American nuclear power facilities is not maintained or inspected as diligently as the original components. According to the experts, the United States has analyzed the risk of losing power from the grid or from on-site emergency generators, but not both at the same time. The task force was formed in the wake of Japan’s Fukushima Daiichi nuclear plant disaster, in which both sources of power were simultaneously disabled.