Corium (nuclear reactor) from the pre-meltdown reactor or be due to spontaneous fission of reactor-created actinides. In the absence of adequate cooling, the materials inside of the reactor vessel overheat and deform as they undergo thermal expansion, and the reactor structure fails once the temperature reaches the melting point of its structural materials. The corium melt then accumulates at the bottom of the reactor vessel. In the case of adequate cooling of the corium melt, the melt can solidify and the spread of damage is limited to the reactor itself. However, corium may melt through the reactor vessel and flow out or be
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