Nuclear safety and security called a nuclear meltdown. After shutting down, for some time the reactor still needs external energy to power its cooling systems. Normally this energy is provided by the power grid to which that plant is connected, or by emergency diesel generators. Failure to provide power for the cooling systems, as happened in Fukushima I, can cause serious accidents. Nuclear safety rules in the United States "do not adequately weigh the risk of a single event that would knock out electricity from the grid and from emergency generators, as a quake and tsunami recently did in Japan", Nuclear Regulatory Commission officials
Anti-nuclear movement in the United States do better to contemplate a radical redesign, or if that was not possible, to abandon such technology entirely. Nuclear power plants are a complex energy system. and opponents of nuclear power have criticized the sophistication and complexity of the technology. Helen Caldicott has said: "... in essence, a nuclear reactor is just a very sophisticated and dangerous way to boil water – analogous to cutting a pound of butter with a chain saw." These critics of nuclear power advocate the use of energy conservation, efficient energy use, and appropriate renewable energy technologies to create our energy future. Amory Lovins, from