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
Cooling pond of up to 50 years in the area. The Columbia station in Pardeeville, Wisconsin is a coal fired power plant with a capacity of 1000 MW. A duel cooling system is used for heat rejection that consists of a cooling pond and two cooling towers. The pond and towers are connected in a parallel arrangement to help dissipate thermal energy at expedited rates. In 1994 North Korea's Yongbyon reactor was under U.S scrutiny and thus its nuclear fuel rods were taken out of the reactor and placed in the Yongbyon's cooling pond. They have since been removed. Cooling pond A