Nuclear power station. Night-time view across water of the Three Mile Island nuclear power plant near Harrisburg, Pennsylvania, USA. Hot water is evaporating from the cooling towers (lower frame). This cools the remaining water down so that it can be re-used. The plant's Unit 2 reactor was severely damaged in an accident on 28th March 1979. A loss of reactor cooling water resulted in the exposure of fuel rods, some of which melted, burned through the reactor chamber lining and sank to the floor of the reactor building. Although the radiation release from this partial meltdown was relatively small, public fears about safety were heightened.